JP2001035772A - Aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve exposure accuracy by reducing the influences of vibration of an illumination optical system during exposure on a light exposure main part. SOLUTION: An illumination optical system IOP is separated into a first optical system part IOP1, including a blade which is movable during light exposure operation and a second optical system part IOP2 which does not include a movable part above the movable blade movable during the light exposing operation, the second optical system part IOP2 is installed on a main body column 14, forming a light exposure main body, and the first optical system part is installed separated from the light exposure main body. Thus even if the movable blade moves by a large extent during the light exposure, this involves generation of vibration in the first system part IOP1 and residual vibration remains during the light exposure and the vibration will have no adverse effect on the second optical system part and the light exposure main body provided therewith. Accordingly the influences of the vibration of the illumination optical system on the light exposure main body during the light exposure can be reduced, thus resulting in improved exposure accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an exposure apparatus, and more particularly, to an exposure apparatus used in a lithography process for manufacturing a semiconductor device, a liquid crystal display device, and the like.

[0002]

2. Description of the Related Art In recent years, in a lithography process for manufacturing a semiconductor device or the like, a rectangular or arc-shaped illumination region on a mask or a reticle (hereinafter, collectively referred to as a “reticle”) on which a pattern is formed is illuminated with illumination light. A so-called slit scan method in which a reticle and a substrate such as a wafer are synchronously moved in a one-dimensional direction and the pattern is sequentially transferred onto the substrate.
A scanning exposure apparatus such as a step-and-scan method is used.

In such an apparatus, a movable member movable during an exposure operation in an illumination optical system for illuminating a reticle R with illumination light from a light source, for example, a portion outside a pattern area on a reticle during exposure is not unnecessarily exposed. Thus, a movable blade (also referred to as a movable blind) for limiting an illumination area on the reticle is provided, and the movable blind is driven in synchronization with the reticle during exposure (Japanese Patent Laid-Open No. 4-196513). And the corresponding US Pat. No. 5,473,410).

[0004]

In the process of manufacturing a semiconductor device, it is required to transfer a pattern formed on a reticle onto a wafer while accurately superposing the pattern on the wafer.

However, as described above, in the scanning type exposure apparatus, since the movable member which is movable during the exposure operation is provided in the illumination optical system, the vibration of the illumination optical system caused by the movement of the movable member causes the vibration. This has had an adverse effect on the exposure main body holding the illumination optical system. That is, the exposure main body includes a reticle stage for holding the reticle R, a projection optical system for projecting the pattern of the reticle R onto the wafer, and a wafer stage for holding the wafer. Since a main body column holding the illumination optical system, a laser interferometer mounted on the main body column and measuring the positions of both stages, etc. are included, the vibration of the illumination optical system during the above-described exposure operation, particularly the residual vibration during the exposure, The vibration affected the synchronization accuracy between the reticle stage and the wafer stage, the relative positional relationship between the projection optical system and both stages, and the interferometer measurement values, resulting in the deterioration of the exposure accuracy of the scanning exposure apparatus. .

[0006] If vibrations occur in the illumination optical system during exposure, the vibrations adversely affect the exposure accuracy, as is the case with a static exposure type exposure apparatus such as a step-and-repeat system.

The present invention has been made under such circumstances, and an object of the present invention is to reduce the influence of vibration of an illumination optical system during exposure on an exposure main body, thereby improving exposure accuracy. It is an object of the present invention to provide an exposure apparatus capable of performing the above-described steps.

[0008]

According to a first aspect of the present invention, there is provided an illumination optical system (IOP) for illuminating a mask (R) on which a predetermined pattern is formed with an energy beam, and the illumination optical system (IOP) emitted from the mask. An exposure body (14, RST, PL, WS) including at least a substrate stage (WST) holding a substrate (W) exposed by an energy beam
T) and the illumination optical system,
A first movable portion (BL) movable during an exposure operation;
A partial optical system (IOP1);
The second excluding the movable part that moves more than the movable amount of the movable part
The exposure apparatus is separated into a partial optical system (IOP2), the second partial optical system is installed on the exposure main body, and the first partial optical system is installed separately from the exposure main body.

According to this, the illumination optical system includes a first partial optical system including a first movable portion movable during an exposure operation, and a movable optical system movable by an amount equal to or more than the movable amount of the first movable portion during an exposure operation. The second partial optical system is separated from the exposure main body, and the second partial optical system is installed on the exposure main body. The first partial optical system is installed separately from the exposure main body. Even if the first movable part largely moves, vibrations are generated in the first illumination optical system, and even if residual vibrations of the vibrations remain during the exposure, the vibrations are generated by the second partial optical system and the vibration of the second partial optical system. The adverse effect is hardly exerted on the exposed main body. Therefore, according to the present invention, the influence of the vibration of the illumination optical system during exposure on the exposure main body can be reduced, and as a result, the exposure accuracy can be improved.

In this case, the second partial optical system (IOP2) is an optical member which is stationary during the exposure operation, that is, a non-movable optical member or a non-exposed optical member. The second partial optical system may include less than the first movable portion during the exposure operation. A second movable part that moves by an amount may be included. Even in the latter case, the vibration of the second partial optical system and the vibration of the exposure main body during exposure are
The residual vibration of the first partial optical system is transmitted to the second partial optical system and the exposure main body as it is, and thus is clearly reduced as compared with the vibration of the conventional exposure apparatus.

In the exposure apparatus according to each of the first to third aspects of the present invention, as in the fourth aspect of the present invention, the first partial optical system (IOP1) and the second partial optical system (IOP)
OP2) may include illumination system housings (26A, 26B) that isolate the interior from outside air and make the interior airtight. In such a case, since the first partial optical system and the second partial optical system are each provided with an illumination system housing that separates the interior from the outside air and makes the interior airtight, each of the illumination system housings has low absorption. By purging a gas such as a nitrogen (N ₂ ) gas or a helium (He) gas having a concentration of oxygen equal to or less than a predetermined value, preferably 1 ppm or less, absorption in the first partial optical system and the second partial optical system is performed. Absorption of an energy beam by a reactive gas (oxygen, water vapor, hydrocarbon gas, or the like) can be suppressed. As the energy beam, for example, an energy beam having a wavelength of 300 nm or less (KrF excimer laser light having a wavelength of 248 nm, wavelength 193n)
high-precision exposure (transfer of a mask pattern onto a substrate) using an ArF excimer laser beam of m.

In this case, the space between the first illumination system housing (26A) constituting the first partial optical system and the second illumination system housing (26B) constituting the second partial optical system is separated from the outside air. It is preferable to further include a connection part (94) for separating the first illumination system housing and the second illumination system housing in an airtight state, and connecting the first illumination system housing and the second illumination system housing in a state in which transmission of vibration therebetween is restricted. In such a case, the connection section separates the space between the first illumination system housing forming the first partial optical system and the second illumination system housing forming the second partial optical system from the outside air and makes the space airtight. Since the low-absorbing gas is purged into the space between the first and second illumination system housings, the absorption of the energy beam by the absorptive gas can be suppressed even in that portion. . At the connection,
Since the first illumination system housing and the second illumination system housing are connected in a state where the transmission of vibration therebetween is restricted, the first illumination system housing and the second illumination system housing are connected to each other.
Even if the vibration of the illumination system housing during the exposure operation is transmitted to the second illumination system housing and the exposure main body, the influence on the exposure accuracy is small. Therefore, as an energy beam,
For example, an energy beam belonging to a vacuum ultraviolet region having a wavelength of 200 nm or less (an F ₂ laser beam having a wavelength of 157 nm, a wavelength of 146
A more accurate exposure can be performed using a Kr ₂ laser having a wavelength of nm or an Ar ₂ laser having a wavelength of 126 nm.

[0013] In this case, as in the invention according to claim 6, the connecting portion can be formed of a bellows-shaped member that can be extended and contracted.

In the exposure apparatus according to the first aspect of the present invention, as in the seventh aspect of the present invention, the first partial optical system (IOP1) includes an optical integrator and a portion near an exit surface of the optical integrator. And at least one of an iris diaphragm and an illumination system aperture diaphragm plate (28G) having at least one aperture diaphragm disposed in the first movable part, wherein the first movable part is provided with one of the apertures on the illumination system aperture diaphragm plate. The optical apparatus may further include a switching device for positioning one of the stop and the iris stop on the exit surface of the optical integrator.

Further, in the exposure apparatus according to the first aspect, as in the invention according to the eighth aspect, the first movable section is movable to limit an irradiation area of the energy beam on the mask during exposure. It may be a blade.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG. FIG. 1 schematically shows an overall configuration of an exposure apparatus 10 according to one embodiment, which includes an illumination optical device according to the present invention as an illumination optical system.

The exposure apparatus 10 synchronously moves a reticle R as a mask and a wafer W as a substrate in a one-dimensional direction (here, the Y-axis direction, which is the horizontal direction in FIG. 1). This is a step-and-scan type scanning exposure apparatus that transfers a circuit pattern formed on the reticle R to each shot area on the wafer W via the projection optical system PL, that is, a so-called scanning stepper.

The exposure apparatus 10 includes a light source 12 and the light source 12.
An illumination optical system IOP as an illumination optical device for illuminating the reticle R with illumination light from the reticle R, a reticle stage RST as a mask stage for holding the reticle R, and illumination light (pulse ultraviolet light) emitted from the reticle R are applied to the wafer W. And a wafer stage WST as a substrate stage for holding a wafer W. Further, the exposure apparatus 10 includes a part of the illumination optical system IOP,
The apparatus includes a main body column 14 for holding the reticle stage RST, the projection optical system PL, the wafer stage WST, and the like, an anti-vibration unit for suppressing or eliminating vibration of the main body column 14, and a control system for these.

The light source 12 has a wavelength of 19 here.
An ArF excimer laser light source that outputs pulsed ultraviolet light narrowed so as to avoid an oxygen absorption band between 2 and 194 nm is used, and the main body of the light source 12 is a floor in a clean room of a semiconductor manufacturing plant. It is installed on the surface FD. The light source 12 is provided with a light source control device (not shown).
0 (not shown in FIG. 1; see FIG. 7); control of oscillation center wavelength and spectral half width of pulsed ultraviolet light to be emitted; trigger control of pulse oscillation; control of gas in laser chamber And so on.

[0020] Incidentally, as the light source 12 may be used F ₂ laser light source for outputting a pulsed ultraviolet light of KrF excimer laser light source or a wavelength 157nm for outputting a pulse ultraviolet light having a wavelength of 248 nm. Further, the light source 12 is provided in another room (service room) having a lower degree of cleanness than the clean room,
Alternatively, it may be installed in a utility space provided under the floor of a clean room.

The light source 12 is not shown in FIG. 1 for convenience of drawing, but is actually connected to one end (incident end) of the beam matching unit BMU via a light-blocking bellows and a pipe. The other end (exit end) of the beam matching unit BMU is connected to a later-described first partial illumination optical system IOP1 of the illumination optical system IOP via a pipe 16 having a relay optical system built therein.

As shown in FIG. 2, the beam matching unit BMU is provided with a relay optical system 18, a plurality of movable reflecting mirrors 20A and 20B, and the like. The optical path of the narrow band pulsed ultraviolet light (ArF excimer laser light) incident from the light source 12 using 20A, 20B or the like is positionally matched with the first partial illumination optical system IOP1 described below. .

The illumination optical system IOP is composed of two parts, a first partial illumination optical system IOP1 as a first partial optical system and a second partial illumination optical system IOP2 as a second partial optical system. As will be described later, the first partial illumination optical system IOP1 is provided with a separation frame 22 (not shown in FIG. 1) installed on a base plate BP called a frame caster, which is a reference of an apparatus horizontally mounted on the floor FD. , See FIG. 2), and the rest is retained.
In addition, as shown in FIG. 1, the second partial illumination optical system IOP2 is supported from below by a second support column 52 which constitutes the main body column 14, which will be described later.

Here, the illumination optical system I will be described with reference to FIG.
Each component of the OP will be described.

As shown in FIG. 2, the first partial illumination optical system IOP1 includes a mirror M1, a variable dimmer 28A,
A beam shaping optical system 28B, a mirror M2, a first fly-eye lens system 28C as an optical integrator,
A focusing optical system 28D, a vibrating mirror 28E, a second fly-eye lens system 28F as an optical intaglator,
An illumination system aperture stop plate 28G, a beam splitter 28H, a first relay lens system 28I, and a movable reticle blind 28J (not shown in FIG. 2, see FIG. 1) as a movable field stop constituting a reticle blind mechanism are provided. ing.

The second partial illumination optical system IOP2 includes an illumination system housing 26B as a second illumination system housing.
And a fixed reticle blind 28K and a lens 28 housed in a predetermined positional relationship within the illumination system housing 26B.
L, mirror M3, second relay lens system 28M, mirror M
4. It has a main condenser lens 28N and the like.

The components of the illumination optical system IOP will be described in more detail.

The variable dimmer 28A adjusts the average energy of each pulse of the pulsed ultraviolet light. Here, a plurality of ND filters having different dimming rates are provided at a predetermined angular interval on a rotatable disk. (Turret) is used, and the dimming rate can be changed stepwise by adjusting the rotation angle of the disk. The rotating plate constituting the variable dimmer 28A includes a driving mechanism 29 including a motor controlled by an illumination control device 30 (not shown in FIG. 1 and see FIG. 7) which will be described later under the control of the main control device 50. (Not shown in FIG. 1; see FIG. 7). It should be noted that a variable dimmer may be used that continuously varies the dimming rate by adjusting the degree of overlap between two optical filters whose transmittance continuously changes.

The beam shaping optical system 28B is provided with a double fly-eye lens system described later provided with a cross-sectional shape of the pulsed ultraviolet light adjusted to a predetermined peak intensity by the variable dimmer 28A behind the optical path of the pulsed ultraviolet light. Is shaped so as to be similar to the entire shape of the incident end of the first fly-eye lens system 28C constituting the incident end of the first fly-eye lens system 28C, and is efficiently incident on the first fly-eye lens system 28C. It is constituted by a two-unit zoom optical system including a beam expander and the like.

The double fly-eye lens system is for uniformizing the intensity distribution of the illumination light, and the first fly-eye lens system is sequentially arranged on the optical path of the pulsed ultraviolet light behind the beam shaping optical system 28B. 28C and condenser lens system 28D
And a second fly-eye lens system 28F.

As the first fly-eye lens system 28C,
Here, a turret in which a fly-eye lens is mounted on a rotatable disk is used.
Therefore, by rotating the disk, the fly-eye lens can be accurately positioned on the optical path of the pulsed ultraviolet light.

The condenser lens system 28D collects light from a surface light source (a large number of point light sources) formed at the exit end of the first fly-eye lens system 28C, as will be described later. This is for moving the lens to the second fly-eye lens system 28F, which has three convex or positive lenses, and continuously changes the entire focal length while keeping the imaging position on the same plane. A three-group zoom optical system of a mechanical correction type employing a zoom cam mechanism is used. The driving principle of the movable lens constituting the condenser lens system 28D will be described later in detail.

Between the condenser lens system 28D and the second fly-eye lens system 28F, a vibrating mirror 28E for smoothing interference fringes and weak speckles generated on the irradiated surface (reticle surface or wafer surface). Is arranged. The vibration (deflection angle) of the vibration mirror 28E is controlled by an illumination control device 30 under the control of the main control device 50 via a drive system (not shown). A configuration in which the same double fly-eye lens system and vibrating mirror as in the present embodiment are combined is disclosed in detail in, for example, Japanese Patent Application Laid-Open No. 1-259533 (and corresponding US Pat. No. 5,307,207). ing.

In the vicinity of the exit surface of the second fly-eye lens system 28F, an illumination system aperture stop plate 28 made of a disc-shaped member is provided.
G is arranged. The illumination system aperture stop plate 28G has an aperture stop made of, for example, a normal circular aperture, an aperture stop made of a small circular aperture for reducing the σ value which is a coherence factor, and an annular stop for annular illumination at substantially equal angular intervals. A ring-shaped aperture stop, a modified aperture stop formed by eccentrically arranging four apertures, and the like for the modified light source method are arranged. The illumination system aperture stop plate 28G is rotationally driven by a motor 32 (not shown in FIG. 2; see FIG. 7) controlled by the illumination control device 30, and one of the aperture stops is moved to the second fly-eye lens system 28F. Is positioned on the exit surface. That is, in the present embodiment, a switching device is configured in which any of the aperture stops on the illumination system aperture stop plate 28G is positioned on the exit surface of the optical integrator by the motor 32.

A beam splitter 28H having a large transmittance and a small reflectance is arranged on the optical path of the pulsed ultraviolet light behind the illumination system aperture stop plate 28G.
First relay lens system 28I, movable reticle blind 2
8J (not shown in FIG. 2; see FIG. 1) are sequentially arranged.

The movable reticle blind 28J includes, for example, two L-shaped movable blades as a first movable portion,
And an actuator for driving the movable blade. The positions of the two movable blades in the direction corresponding to the scanning direction of the reticle R and the direction corresponding to the non-scanning direction orthogonal to the scanning direction are variable. The movable reticle blind 28J is used to prevent unnecessary portions from being exposed,
At the start and end of the scanning exposure, the movable blade is used to further limit the illumination area on the reticle R defined by the fixed reticle blind 28K as described later. The movable reticle blind 28J is controlled by the main controller 50.

Further, the light source 1 of the beam splitter 28H
On the reflected light path from the second side, an integrator sensor 34 composed of a photoelectric conversion element is arranged.
On the reflected light path from the reticle R side of 8H, a reflected light monitor 38 composed of a photoelectric conversion element similar to the integrator sensor 34 is arranged.

The fixed reticle blind 28K is arranged on a surface slightly defocused from a conjugate plane with respect to the pattern surface of the reticle R near the incident end of the illumination system housing 26B, and has a predetermined shape that defines an illumination area on the reticle R. An opening is formed. The opening of the fixed reticle blind 28K has a slit shape linearly extending in the X-axis direction orthogonal to the moving direction (Y-axis direction) of the reticle R during scanning exposure at the center of the circular visual field of the projection optical system PL. It is assumed to be formed in a rectangular shape.

The reason why the arrangement surface of the fixed reticle blind 28K is slightly defocused from the conjugate plane with respect to the pattern surface of the reticle R is mainly that of a scanning type exposure apparatus, particularly an apparatus using pulsed light as exposure illumination light. The illuminance distribution of the pulse light in the direction on the reticle (wafer) on the reticle (wafer) is trapezoidal (that is, the shape has slopes at both ends), and the distribution of the integrated exposure amount in each shot area on the wafer during scanning exposure Is to be substantially uniform.

The second relay lens system 28M housed in the illumination system housing 26B includes a first relay lens system 2M.
8I together with the relay optical system.
A mirror M4 that reflects the pulsed ultraviolet light that has passed through the second relay lens system 28M toward the reticle R is disposed on the optical path of the pulsed ultraviolet light behind the relay lens system 28M,
A main condenser lens system 28N is arranged on the optical path of the pulsed ultraviolet light behind the mirror M4. Each relay lens system 28 housed in the illumination system housing 26B.
At least one of the lens M, the lens 28L, and the mirror M4 is configured such that its optical axis is movable with respect to the optical axis of another lens or mirror during the non-exposure operation.

In the above configuration, the entrance surface of the first fly-eye lens system 28C, the entrance surface of the second fly-eye lens system 28F, the blade arrangement surface of the movable reticle blind 28J, and the pattern surface of the reticle R are optically A light source surface formed on the exit surface side of the first fly-eye lens system 28C, a light source surface formed on the exit surface side of the second fly-eye lens system 28F, and a Fourier transform surface of the projection optical system PL are set to be conjugate to each other. The (exit pupil plane) is set to be optically conjugate to each other, forming a Koehler illumination system.

Next, the operation of the illumination optical system IOP configured as described above, that is, the first partial illumination optical system IOP1 and the second partial illumination optical system IOP2 will be briefly described.
When the pulsed ultraviolet light from the light source 12 is horizontally incident on the first partial illumination optical system IOP1 via the beam matching unit BMU and the relay optical system, the pulsed ultraviolet light becomes
The optical path is bent vertically upward by the mirror M1, enters the variable attenuator 28A, and is adjusted to a predetermined peak intensity by one of the ND filters of the variable attenuator 28A. Incident. Then, the cross-sectional shape of the pulsed ultraviolet light is shaped by the beam shaping optical system 28B so as to efficiently enter the rear first fly-eye lens system 28C. Next, the pulsed ultraviolet light is transmitted to the first fly-eye lens system 2 via the mirror M2.
When the light enters 8C, a surface light source, that is, a secondary light source composed of a large number of light source images (point light sources) is formed on the exit end side of the first fly-eye lens system 28C. The pulsed ultraviolet light diverging from each of these multiple point light sources is collected by a condenser lens system 28D,
Then, the light enters the second fly-eye lens system 28F via a vibrating mirror 28E that reduces speckle due to the coherence of the light source. Thereby, the second fly-eye lens system 28F
A tertiary light source in which a large number of light source images are uniformly distributed in an area of a predetermined shape is formed at the exit end of the light source. The pulsed ultraviolet light emitted from this tertiary light source passes through one of the aperture stops on the illumination system aperture stop plate 28G, and then reaches a beam splitter 28H having a large transmittance and a small reflectance.

Most of the pulsed ultraviolet light (eg, about 97%) is transmitted through the beam splitter 28H, and the remaining part (eg, about 3%) is reflected. After passing through the first relay lens system 28I and the opening of the blade of the movable reticle blind 28J, the pulsed ultraviolet light as the exposure light transmitted through the beam splitter 28H passes through the opening of the fixed reticle blind 28K with a uniform intensity distribution. Light up.

The pulsed ultraviolet light that has passed through the opening of the fixed reticle blind 28K reaches the mirror M3 via the lens 28L, where the optical path is bent horizontally. Next, this pulsed ultraviolet light is transmitted to the second relay lens system 2.
After passing through 8M, the optical path is bent vertically downward by the mirror M4, and then passes through the main condenser lens system 28N.
A predetermined illumination area (slit or rectangular illumination area extending linearly in the X-axis direction) on reticle R held on reticle stage RST is illuminated with a uniform illuminance distribution.
Here, the rectangular slit-shaped illumination light applied to the reticle R is set to be elongated in the X-axis direction (non-scanning direction) at the center of the circular projection field of the projection optical system PL in FIG. The width of the light in the Y-axis direction (scanning direction) is set substantially constant.

On the other hand, the pulsed ultraviolet light reflected by the beam splitter 28H enters the integrator sensor 34, where it is photoelectrically converted. Then, the photoelectric conversion signal of the integrator sensor 34 is supplied to the main controller 50 via a peak hold circuit and an A / D converter (not shown). As the integrator sensor 34, for example, a PIN-type photodiode or the like having sensitivity in a vacuum ultraviolet region and having a high response frequency for detecting pulse light emission of the light source 12 can be used. The correlation coefficient between the output of the integrator sensor 34 and the illuminance (exposure amount) of the pulsed ultraviolet light on the surface of the wafer W is obtained in advance and stored in a memory in the main controller 50.

The light reflected from the pattern surface of the reticle R passes through the main condenser lens system 28N, the mirror M4, and the second
The reflected light is reflected by the beam splitter 28H through the relay lens system 28M, the mirror M3, the lens 28L, the opening of the fixed reticle blind 28K, the opening of the blade of the movable reticle blind 28J, and the first relay lens system 28I in order. And then photoelectrically converted there. The photoelectric conversion signal of the reflected light monitor 38 is supplied to the main controller 50 via a peak hold circuit (not shown) and an A / D converter. The reflected light monitor 38 is used, for example, when measuring the transmittance of the reticle R.

The housing for holding each optical member constituting the illumination optical system IOP, the joint structure between these housings, and the like will be described later in further detail.

Returning to FIG. 1, the main body column 14 includes a plurality of (four in this case) provided on the base plate BP.
Support members 40A to 40D (however, the support 40
C and 40D are not shown) and these support members 40A to 40D.
Vibration isolation units 42A fixed to the upper part of 40D, respectively
1 to 42D (however, in FIG. 1, the anti-vibration units 42C and 42D on the back side of the paper surface are not shown, see FIG. 7). A hanging column 46 suspended downward from the lower surface of the
First and second support columns 4 provided on a barrel base 44
8, 52.

The anti-vibration units 42A to 42D are connected in series (or in parallel) on the upper portions of the support members 40A to 40D, respectively.
And a voice coil motor which is provided with an adjustable internal pressure. By these vibration isolation units 42A to 42D, micro vibrations transmitted from the floor FD to the lens barrel base 44 via the base plate BP and the support members 40A to 40D are insulated at the micro G level.

The lens barrel base 44 is made of a casting or the like, and has a circular opening in a plan view at the center thereof. Inside the projection optical system PL, the optical axis direction is the Z-axis direction. Has been inserted. A flange FLG integrated with the lens barrel is provided on the outer periphery of the lens barrel of the projection optical system PL. As a material of the flange FLG, a material having low thermal expansion, for example, Invar (nickel 36)
%, Manganese 0.25%, and a low-expansion alloy composed of iron containing trace amounts of carbon and other elements). A so-called kinematic support mount that supports at three points via points, surfaces and V-grooves is configured. When such a kinematic support structure is adopted, the projection optical system PL
Is easy to assemble with the lens barrel base 44, and the stress caused by vibration, temperature change, posture change, and the like of the lens barrel base 44 and the projection optical system PL after assembly can be reduced most effectively. .

The hanging column 46 includes a wafer base plate 54 and four hanging members 56 for hanging the wafer base plate 54 in a substantially horizontal manner.

The first support column 48 is mounted on the upper surface of the lens barrel base 44 so as to surround the projection optical system PL.
It includes a leg 58 (a leg on the far side of the drawing is not shown) and a reticle base platen 60 supported substantially horizontally by the four legs 58.

Similarly, the second support column 52 has four support columns 62 (the support columns on the back side of the paper are illustrated) that are planted on the upper surface of the lens barrel base 44 so as to surround the first support column 48. (Omitted) and a top plate 64 supported substantially horizontally by these four columns 62. The above-described second partial optical system IOP2 is supported by the top plate 64 of the second support column 52.

Although not shown in FIG. 1, the lens barrel base 44 constituting the main body column 14 is actually provided with three vibration sensors (for measuring the vibration of the main body column 14 in the Z direction). For example, three vibration sensors (for example, an accelerometer) and an accelerometer that measures the vibration in the XY plane directions (for example, two of these vibration sensors measure the vibration of the main body column 14 in the Y direction, and the remaining vibration sensors). Is the X of the body column 14
To measure the vibration in the direction). In the following, these six vibration sensors are collectively referred to as a vibration sensor group 66 for convenience. The measurement value of the vibration sensor group 66 is supplied to the main controller 50 (see FIG. 7). Therefore, main controller 50 controls main body column 1 based on the measurement value of vibration sensor group 66.
It is possible to obtain the vibration in the direction of 4 6 degrees of freedom. In the main controller 50, for example, the reticle stage RS
T, during the movement of the wafer stage WST, etc., in order to eliminate the vibration in the six degrees of freedom direction of the main body column 14 obtained based on the measurement values of the vibration sensor group 66,
The 2D speed control is performed by, for example, feedback control or feedback control and feedforward control, so that vibration of the main body column 14 can be effectively suppressed.

The reticle stage RST is arranged on a reticle base platen 60 that forms the first support column 48 that forms the main body column 14. The reticle stage RST includes, for example, a reticle stage drive system 68 (FIG. 1) including a magnetic levitation type two-dimensional linear actuator.
In FIG. 7, the reticle R is linearly driven on the reticle base surface plate 42 with a large stroke in the Y-axis direction, and the reticle R is rotated in the X-axis direction and the θz direction (the rotation direction around the Z-axis). Also has a configuration capable of minute driving.

A part of the reticle stage RST includes
A movable mirror 72 that reflects a length measurement beam from a reticle laser interferometer 70, which is a position detection device for measuring the position and the movement amount, is attached. The reticle laser interferometer 70 is fixed to the reticle base surface plate 60, and the position (θz) of the reticle stage RST in the XY plane with respect to the fixed mirror Mr fixed to the upper end side surface of the projection optical system PL.
(Including rotation) with a resolution of, for example, about 0.5 to 1 nm.

Reticle stage RST (that is, reticle R) measured by reticle laser interferometer 70 described above.
Is sent to the main controller 50 (see FIG. 7). Main controller 50 basically controls reticle stage drive system 68 such that the position information (or speed information) output from reticle laser interferometer 70 matches the command value (target position, target speed).

As the projection optical system PL, here,
Both the object plane (reticle R) side and the image plane (wafer W) side are telecentric and have a circular projection visual field, and are only composed of a refractive optical element (lens element) using quartz or fluorite as an optical glass material. , 1/5, or 1/6 reduction refractive optical systems are used. For this reason, when the reticle R is irradiated with pulsed ultraviolet light, an image forming light beam from a portion of the circuit pattern area on the reticle R illuminated by the pulsed ultraviolet light enters the projection optical system PL, and the circuit pattern Is formed at the center of the circular field on the image plane side of the projection optical system PL in the form of a slit or a rectangle (polygon) at each pulse irradiation of the pulsed ultraviolet light. This allows
The projected partial inverted image of the circuit pattern is formed by the projection optical system P
The reduced transfer is performed to the resist layer on the surface of one of the plurality of shot regions on the wafer W arranged on the image plane L.

The wafer stage WST is arranged on a wafer base surface plate 54 constituting the above-mentioned hanging column 46, and includes, for example, a wafer stage driving system 74 (FIG. 1 (Not shown, see FIG. 7) so as to be freely driven in the XY plane.

A wafer W is fixed on the upper surface of wafer stage WST via a wafer holder 76 by vacuum suction or the like. The XY position and the amount of rotation (the amount of yawing, the amount of rolling, and the amount of pitching) of wafer stage WST are fixed to a part of wafer stage WST with reference to reference mirror Mw fixed to the lower end of the barrel of projection optical system PL. The measurement is performed in real time at a predetermined resolution, for example, a resolution of about 0.5 to 1 nm by a wafer laser interferometer 80 that measures a change in the position of the mirror 78. The measurement value of the wafer laser interferometer 80 is supplied to the main controller 50 (see FIG. 7).

In the exposure apparatus 10 of the present embodiment, the main body column 14 described above, the reticle stage RST supported by the main body column 14, the wafer stage WST, and the projection optical system P
The exposure main body is constituted by L and the like.

Next, the first, which constitutes the illumination optical system IOP,
A housing for holding the optical members of the second partial illumination optical systems IOP1 and IOP2 and a joint structure thereof will be described in detail with reference to FIGS.

FIG. 3 is a sectional view showing the entirety of the second partial illumination optical system IOP2 and a part of the first partial illumination optical system IOP1. As apparent from FIG. 3, the illumination optical system IOP includes at least one optical member (an optical element such as a lens or a mirror, or an aperture or a blade of a reticle blind) and a housing that holds the optical member. And a plurality of optical units.

[0064] When this further detail, the second partial illumination optical system IOP2, as shown in FIG. 3, an optical unit 84 ₁ having a housing 82A which holds the main condenser lens 28N and this mirror M4 and optical having an optical unit 84 _2, an optical unit 84 ₃ having a second housing 82C which holds the relay lens system 28M and this, a housing 82D for holding the mirror M3 and the same having a casing 82B for holding the Unit 84 ₄ and lens 28
An optical unit 84 ₅ with L and the housing 82E that holds it, and the optical unit 84 ₆ having a fixed reticle blind 28K and the housing 82F for holding this is configured by sequentially joined.

[0065] The second optical unit constituting the partial illumination optical system IOP2 84 ₁ -84 _6, the optical elements such as the respective optical member held in the housing non-movable lenses or mirrors or immovable fixed, This is a second optical unit that is a reticle blind (field stop). If the mutual positional relationship between these lenses and mirrors is set to a predetermined positional relationship, subsequent adjustments and the like are not required, and the positional relationship can be set with sufficient accuracy. The housings that make up the unit are second
O-rings 86 ₁ , 86 ₂ , 86 ₃ , 8 as joining members for
6 _4, 86 ₅ and the relative movement is limited through are joined.

In the present embodiment, the O-rings 86 _{1 to} 86 ₅ have the hollow cross-sectional shape shown in FIG.
A material made of fluorine rubber which has been subjected to secondary vulcanization at a temperature of about 240 ° C. for about 24 hours is used. Where O
The reason why the rings 86 _{1 to} 86 ₅ are formed in a hollow shape is that, by increasing the crushing allowance, the rings 86 _{1 to} 86 ₅ are easily crushed as shown in FIG. This is because the workability is improved. Therefore, the shape is not limited to a hollow shape, and may be any shape that allows a large crushing allowance.
An O-ring 186 having a cross-sectional shape as shown in FIG. In this case, as shown in FIG.
It can be easily crushed. Also, the use of the secondary vulcanized fluororubber is based on the fact that fluororubber, which is originally a chemical-clean material, is replaced with a more chemical-clean material that removes impurities during secondary vulcanization and reduces degassing. It is because it becomes. In addition, as the O-rings 86 _{1 to} 86 ₅ , at least the surface may be a chemical O-ring, for example, a resinous O-ring whose surface is coated with a fluorine-based resin.

Cases 82A, 82B, 82C, 82D, 8
The inner surfaces of 2E and 82F are subjected to a chemical clean treatment by, for example, coating a fluorine-based resin or forming a metal film (a ceramic film, a stainless steel film, or the like) by plasma spraying. Alternatively, a chemically clean material such as stainless steel or Teflon may be used as the material of the housings 82A to 82F themselves. Note that all the O-rings and housings described below are formed in the same manner as described above.

Cases 82A, 82B, 82C, 82D, 8
The illumination system housing 26B is configured by sequentially joining the 2E and 82F as described above. Cover glasses 88A and 88B for blocking external air from contacting the main condenser lens 28N and the lens 28L are attached to the housings 82A and 82E located at both ends (emission end and entrance end) of the illumination system housing 26B, respectively. Have been.

The first partial illumination optical system IOP1 comprises an optical unit 84 ₇ having two L-shaped movable blades BL as a first movable part and a housing 82G for holding the same,
Optical unit 84 ₈ having relay lens system 28I and housing 82H holding the same, optical unit 84 including beam splitter 28H and housing 82I holding the same
_9. Illumination system aperture stop plate 28G and housing 8 holding it
The optical unit 84 ₁₀ having 2J and many other optical units are sequentially joined.

[0070] the housing 8 constituting the optical unit 84 ₇
In 2G, the movable blade BL having a large movable amount is held as an optical member.
It is configured to be driven by an actuator 90 arranged outside the housing 82G. In this case, the movable reticle blind 28J described above is constituted by the two movable blades BL and the actuator 90.
Here, as the actuator 90, for example, a linear motor having a mover supported by an air bearing in a non-contact manner with respect to a guide surface is used. When such an actuator is used, both the degree of cleanliness and the degree of chemical cleanliness can be improved as compared with the case where the movable blade is driven by a rotary motor via a ball screw mechanism. That is, since it is a non-contact drive,
As compared with a contact driven linear guide or the like, dust generation can be reduced, and since a ball screw and a motor bearing are not required, degassing from these can be eliminated, and the degree of chemical cleanliness can be improved.

Further, a sensor 92 for detecting a driving amount of the blade BL by the actuator 90 is provided outside the housing 82G. The output of the sensor 92 is supplied to the main controller 50 (see FIG. 7), and the main controller 50 controls the actuator 90 based on the output of the sensor 92 at the time of scanning exposure so that the blade BL is connected to the reticle R. Synchronous movement prevents unnecessary portions from being exposed.

Here, a method of connecting the housing 82F and the housing 82G, that is, a method of connecting the second partial illumination optical system IOP2 and the first partial illumination optical system IOP1 will be described.

In this case, when the housing 82F and the housing 82G are firmly joined, vibration generated in the housing 82G during the exposure operation due to the driving of the movable blade BL causes the vibration of the housing 82F,
That is, it is undesirably transmitted to the second partial illumination optical system IOP2 side held by the main body column 14 as it is. For this reason, in this embodiment, between the housing | casing 82F and the housing | casing 82G via the elastic bellows-like member 94 as a connection part which can make the inside airtight with respect to external air, They are connected in a state where transmission of vibration between them is restricted.

Here, as the bellows-like member 94, a member made of fluororubber which has been subjected to secondary vulcanization under the same conditions as the above-mentioned O-ring is used.

Similarly to the above, the housing 82G and the housing 82H holding the first relay lens system 28I
As in the case of _{No. 4} , it is joined via an elastic bellows-like member 961 made of fluoro rubber which has been subjected to secondary vulcanization. At least an inner surface thereof chemically cleaned processed as bellows-shaped member 94, 96 _1, for example, it may be used as coated with fluorine-based resin. Further, a metal such as stainless steel may be used as the material of the bellows-like member.

The first relay lens system 28I includes a housing 82H.
The first lens 102 and the non-movable second lens 104 that can be finely driven in the XY shift and tilt directions by an actuator 98 and a moving mechanism (not shown) mounted outside the camera.
And In this case, the optical arrangement of the first relay lens system 28I may be deviated from an expected position by vibration transmitted to the housing 82H via the housing 82G by driving the movable blade BL. Such displacement can be adjusted by finely driving one lens 102 in the XY shift and tilt directions.

Further, a sensor 106 for detecting a driving amount of the lens 102 by the actuator 98 is provided outside the housing 82H. The output of this sensor 106 is
The main controller 50 (see FIG. 7)
At 0, the above-described correction is performed by controlling the actuator 98 based on the output of the sensor 106.

[0078] the housing 8 constituting the optical unit 84 ₉
In 2I, a beam splitter 28H is obliquely arranged at an angle of approximately 45 ° with respect to the optical path of the pulsed ultraviolet light, and the positional relationship between this beam splitter 28H and the fixed lens 104 of the first relay lens system 28I is once determined. after setting the positional relationship, since then it is not necessary to adjust the positional relationship, are joined via an O-ring 86 ₆ the housing 82H and the housing 82I. In this case, the housing 82I is attached to the integrator sensor 3 via the attachment members 107 and 108.
4. The reflected light monitor 38 is mounted from the outside, and the wiring of the optical sensors is arranged outside the housing 82I so that the wiring does not reduce the chemical cleanliness in the housing. Integrator sensor 34, reflected light monitor 3
8 shows a state where only the light receiving surface faces the inside of the housing 82I.

The housing 82J constituting the optical unit 84 ₁₀
, An illumination system aperture stop plate 28G having a rotation shaft 112 is rotatably mounted via a bearing 110, and this illumination system aperture stop plate 28G is used as an actuator provided outside the housing 82J as an actuator. The motor 32 is driven to rotate. A magnetic fluid seal is used between the bearing 110 and the rotating shaft 112. For this reason, a magnetic fluid functioning as a kind of lubricating oil enters into the gap between the rotating shaft 112 and the bearing portion 110, thereby improving the airtightness of the bearing portion 110 and improving the rotating shaft 112.
And smooth rotation can be realized at the same time. As the magnetic fluid in this case, for example, a fluorine-based base oil is used. Since the fluorine-based base oil is a chemical clean substance, it is possible to suppress a decrease in the degree of chemical clean.

The motor 32 is provided outside the housing 82J.
Also provided is a sensor 114 for detecting the amount of rotation of the illumination system aperture stop plate 28G. The output of the sensor 114 is supplied to the main control device 50 (see FIG. 7), and the main control device 50 controls the motor 32 based on the output of the sensor 114 when the illumination condition is switched.

[0081] Further, the housing 82J is secondary vulcanization via the bellows-shaped member 96 _{and second} universal decorated with fluorine rubber or stainless steel expansion is joined to the housing 82I described above.

The housings of the first partial illumination optical system IOP1, especially the housings connected by the bellows-like members, are not supported by the bellows-like members alone. There is a need to keep.

Therefore, as shown in FIG. 3, a flange is provided on the outer peripheral portion of each housing, and the flange of each housing is supported by the illumination system accommodating member 22 a mounted on the separation gantry 22. Form a support member. Then, a circular opening in a plan view is formed in the center of the support member, and the respective housings 82G to 82J are inserted into the openings from above with the optical axis direction thereof being the Z direction, whereby the positions of the respective housings are changed. It can be stably held.

The flange provided on each housing is integrated with the housing, and the materials of the housing and the flange are as follows.
A material having low thermal expansion, for example, the above-described invar is used.

Further, a metal material such as ceramic or stainless steel may be sprayed onto the contact portion between the flange of each housing and the support member of the illumination system housing member 22a in order to accurately hold each housing. desirable.

Further, between the flange of the housing and the support member, the housing is held at three points with respect to the support member via points, surfaces, and V-grooves in the same manner as in the method of supporting the projection optical system PL. A so-called kinematic support mount for supporting may be applied.

As a modification, each of the housings may be directly held on concrete in a semiconductor factory building called a pedestal.

Next, the configuration of the condenser lens system 28D composed of a three-unit zoom optical system and its countermeasures against chemical clean will be described with reference to FIG. In practice, the condenser lens system 28D is a three-group zoom optical system having three lenses. However, in order to avoid complicating the drawing and to make the description easy to understand, in FIG. Only one is shown.

As shown in FIG. 6, the condenser lens system 28D has a bottomed cylindrical portion 122a having an open end and a cylindrical shape extending from the inner bottom surface of the bottomed cylindrical portion 122a to the other end. A pair of support housings 122 having an extended portion 122b
A, 122B, a plurality (three in this case) of vacuum spline shafts 124A, 124B, 124C for coaxially connecting the support housings 122A, 122B, and these vacuum spline shafts 124A, 124B, 1
Cylindrical lens barrel 1 slidably mounted on 24C
26, a magnetic material formed with vacuum bearings 128A and 128B protruding from one side and the other side of the outer peripheral portion of the lens barrel 126, and cam grooves 130a and 130b respectively engaged with the vacuum bearings 128A and 128B. And the like.

The cylindrical cam 130 has bearings (ball bearings) 132A, 1A near its one end in the longitudinal direction and near the other end.
32B, these bearings 132A, 13
It is rotatably supported by the supporting housings 122A and 122B via the respective 2B. Further, the cam grooves 130a,
130b is a diagonal groove formed in the same direction along the peripheral surface of the cylindrical cam 130. A cover 13 that covers the cam grooves 130a and 130B is provided on the outer peripheral portion of the cylindrical cam 130.
4 is mounted via an O-ring.

The vacuum spline shaft 124A,
124B and 124C are provided at approximately 120 ° intervals,
These spline shafts 124A, 124B, 12
In correspondence with 4C, the lens barrel 126 is provided with a linear motion guide member 136 for vacuum containing a ball.

Therefore, the rotation of the cylindrical cam 130 causes the cam grooves 130a and 130b to form the vacuum bearing 128.
A and 128B are respectively guided, and as a result, a lens barrel 126 provided with vacuum bearings 128A and 128B.
Are spline shafts 124A, 124B, 124C
Is reciprocated along.

In the actual condenser lens system, the lens barrels holding the three lenses are individually arranged along nine vacuum spline shafts installed between the supporting housings at approximately 40 ° intervals. It has a moving structure. For this reason, each of the cylindrical cams guides each lens barrel via two vacuum bearings provided for each of the three lens barrels.
And a total of six cam grooves. In addition, the cylindrical cam 130 can be actually driven manually or electrically via a gear mechanism (not shown).

The magnetic fluid holding mechanisms 138 are provided on the inner peripheral surfaces of the support housings 122A and 122B, respectively, corresponding to one end and the other end in the longitudinal direction of the cylindrical cam 130, respectively.
A and 138B are provided respectively. One magnetic fluid holding mechanism 138A includes a ring-shaped permanent magnet 140,
Two ring-shaped yokes 14 fixed to one side and the other side in the longitudinal direction of the spline shaft of the permanent magnet 140
2 and 144, and when the cylindrical cam 130 is not attached to the inner peripheral portion of the magnetic fluid holding mechanism 138A, the yokes 142 and 144 on the inner peripheral surface side of the permanent magnet 140 are provided.
The magnetic fluid F is held by the magnetic force and the surface tension in the gap between them. Then, the magnetic fluid holding mechanism 138
In the state of FIG. 5 in which the cylindrical cam 130 is mounted on the inner peripheral side of A, the permanent magnet 140 → the yoke 142 → the cylindrical cam 130
A magnetic circuit is formed along the path from the yoke 144 to the permanent magnet 140, and the magnetic fluid F enters the gap between the inner peripheral surfaces of the yokes 142 and 144 and the outer peripheral surface of the cylindrical cam to seal the gap. In this case, the cylindrical cam 1
The magnetoresistance of 30 is small. As the magnetic fluid F in this case, for example, a fluorine-based base oil is used. Since the fluorine-based base oil is a chemical clean substance, it is possible to suppress a decrease in the degree of chemical clean. The other magnetic fluid holding mechanism 138B is similarly constructed, and has an inner peripheral surface of the yoke and the cylindrical cam 130.
Is sealed with a magnetic fluid F. The support housings 122A and 122B, the lens barrel 126, the cylindrical cam 130, the cover 134, and the like are made of a chemically clean material, for example, stainless steel.

The beam shaping optical system 28B composed of the two-unit zoom optical system is also configured in the same manner as the above-described condenser lens system 28D, and the movable element is driven in the same manner.

The remaining optical members constituting the first partial illumination optical system IOP1, that is, the second fly-eye lens system 28
F, vibrating mirror 28E, first fly-eye lens system 28
The mirror C, the mirror M2, the beam shaping optical system 28B, the variable dimmer 28A, and the mirror M1 are each held in a casing that has been subjected to the chemical clean processing as described above, and constitute an optical unit. The optical member having a large movable amount, such as the vibrating mirror 28E, the first fly-eye lens system 28C, and the variable dimmer 28A, and the housing for holding the optical member are the first member.
And the remaining fixed optical element or the optical element having a small amount of movement constitutes the second optical unit, and constitutes the housing and the second optical unit constituting the first optical unit. The housing is an elastic bellows-like member 9
6 are joined in a state where relative displacement is allowed through
The housings that constitute the optical unit are fixed (joined) via an O-ring 86 with relative displacement suppressed.
As described above, in the present embodiment, the housings that need to allow relative displacement and the housings that do not need to allow relative displacement are connected to each other via the joining member (O-ring or bellows-like member) suitable for each case. Body-to-body bonding is performed, thus improving the airtightness of the internal space of the housing and the space between adjacent housings.

When the housing holding the non-movable lens is joined to the housing of the adjacent optical unit, the following may be performed. In other words, when subsequent adjustments are unnecessary and the desired positional relationship can be set with sufficiently high precision, the casings are fixed to each other via an O-ring as a joining member in a state where relative displacement is almost completely limited, If later adjustment is required, or if it is difficult to set the desired positional relationship with sufficient accuracy, the housings are joined via a bellows-like member.

In the present embodiment, the illumination system of the first partial illumination optical system IOP1 as a first illumination system housing as a whole is provided by the housing and the bellows-like members constituting the optical units connected sequentially as described above. Housing 26A
(See FIG. 3).

In the exposure apparatus 10 of the present embodiment, the inside of the first illumination system housing 26A and the second illumination system housing 26B constituting the first partial illumination optical system IOP1 and the second partial illumination optical system IOP2, ie, As described above, a clean absorbent having a low absorptive gas, for example, air (oxygen) content of less than 1 ppm is provided in the inner space of the housing and the space between adjacent housings constituting each optical unit having improved airtightness. Dry nitrogen gas (or helium gas) has been purged.

Also, the concentration of a low-absorbing gas, for example, air (oxygen), is 1 in the lens barrel of the projection optical system PL.
A clean dry nitrogen gas (or helium gas) of less than ppm is purged.

FIG. 7 schematically shows a configuration of a control system of the above-described exposure apparatus 10. This control system is mainly configured by a main controller 50 composed of a workstation (or a microcomputer). Main controller 5
Numeral 0 performs various kinds of control described so far, and controls the entire apparatus as a whole.

Next, the exposure operation in the exposure apparatus 10 configured as described above will be described.

As a premise, various exposure conditions for scanning and exposing a shot area on the wafer W with an appropriate exposure amount (target exposure amount) are set in advance. Preparation work such as reticle alignment and baseline measurement using a reticle microscope (not shown) and an off-axis alignment sensor (not shown) is performed, and then fine alignment (EGA (enhanced) of the wafer W using the alignment sensor is performed. (Global alignment) is completed, and the arrangement coordinates of a plurality of shot areas on the wafer W are obtained.

When the preparatory operation for exposure of wafer W is completed, main controller 50 controls wafer stage drive system 74 while monitoring the measurement value of wafer laser interferometer 80 based on the alignment result. Then, wafer stage WST is moved to a scanning start position for exposure of the first shot of wafer W.

Main controller 50 connects reticle stage RST to wafer stage WST via reticle stage drive system 68 and wafer stage drive system 74.
When the scanning in the direction is started and the stages RST and WST reach their respective target scanning speeds, the pattern area of the reticle R starts to be illuminated by the pulsed ultraviolet light, and the scanning exposure is started.

Prior to the start of the scanning exposure, the light source 12
Is started, but the main controller 50 controls the movable blind 28J constituting the reticle blind device.
Movement of each movable blade BL of the reticle stage RST
Is synchronized with the movement of the reticle R, so that the irradiation of the pulse ultraviolet light to the outside of the pattern area on the reticle R is shielded in the same manner as in a normal scanning stepper.

The main controller 50 moves the reticle stage RST in the Y-axis direction especially at the time of the scanning exposure.
And a reticle stage such that the moving speed Vw of wafer stage WST in the Y-axis direction is maintained at a speed ratio corresponding to the projection magnification (1/4, 1/5 or 1/6) of projection optical system PL. Reticle stage RST and wafer stage WS via drive system 68 and wafer stage drive system 74
T is controlled synchronously.

Then, different areas of the pattern area of the reticle R are sequentially illuminated with the pulsed ultraviolet light, and the illumination of the entire pattern area is completed, whereby the scanning exposure of the first shot on the wafer W is completed. Thereby, the pattern of the reticle R is reduced and transferred to the first shot via the projection optical system PL.

When the scanning exposure of the first shot is completed in this way, main controller 50 moves wafer stage WST stepwise in the X and Y axes via wafer stage drive system 74, and exposes the second shot. Is moved to the scanning start position. At the time of this stepping, main controller 50 performs real-time positional displacement of wafer stage WST in the X, Y, and θz directions based on the measurement value of wafer laser interferometer 80 that detects the position of wafer stage WST (the position of wafer W). To measure. Based on the measurement result, main controller 50 controls wafer stage drive system 74 to control the position of wafer stage WST so that the XY position displacement of wafer stage WST is in a predetermined state.

Main controller 50 controls reticle stage drive system 68 based on the displacement information of wafer stage WST in the θz direction, and controls reticle stage RST so as to compensate for the rotational displacement error on wafer W side. Control rotation.

Then, main controller 50 performs the same scanning exposure on the second shot as described above.

In this way, the scanning exposure of the shot on the wafer W and the stepping operation for the next shot exposure are repeatedly performed, and the pattern of the reticle R is sequentially transferred to all the exposure target shots on the wafer W. .

During the stepping operation between shots or during the scanning exposure operation, vibration occurs in the main body column 14 due to the reaction force caused by the movement of each stage.
The main controller detects the vibration of the main body column 14 in the directions of six degrees of freedom based on the output of the vibration sensor group 66, and controls the vibration isolating units 42A to 42D based on the detection result. Is quickly attenuated, and the occurrence of a pattern transfer position shift, an image blur, and the like due to the vibration of the projection optical system PL can be effectively prevented.

As described above in detail, according to the exposure apparatus of the present embodiment, the illumination optical system IOP includes the first partial illumination optical system IOP1 including the movable blade BL (and the vibrating mirror 28E) movable during the exposure operation. And a second partial illumination optical system IOP2 that includes only an optical member that is not movable during the exposure operation. The second partial illumination optical system IOP2 is installed on a main body column 14 that constitutes an exposure main body. The partial illumination optical system IOP2 is installed on a separation gantry 22 separated from the main body column 14. For this reason, the movable blade BL and the like move greatly during the exposure operation, and the first partial illumination optical system IOP1 vibrates accordingly. Even if the residual vibration of this vibration remains during the exposure, the vibration remains at the second level. The partial illumination optical system IOP2 and the exposure main body in which it is installed are hardly adversely affected. Therefore, in the exposure apparatus 10 of the present embodiment, the influence of the vibration of the illumination optical system during exposure on the exposure main body can be reduced, and as a result, the exposure accuracy can be improved.

The first illumination system housing 26A constituting the first partial illumination optical system IOP1 and the second illumination system housing 26B constituting the second partial illumination optical system IOP2 are
The space between the two is connected by an elastic bellows-like member 94 which isolates the space from the outside air and makes it airtight, and the inside is purged with the nitrogen gas (or helium gas). Absorption of pulsed ultraviolet light (energy beam) by gas can be suppressed. Further, in the bellows-like member 94, since the first illumination system housing 26A and the second illumination system housing 26B are connected in a state where the transmission of vibration between them is restricted, the vibration of the first illumination system housing during the exposure operation is restricted. Is transmitted to the second illumination system housing 26B and the exposure main body, the influence on the exposure accuracy is small.

[0116] In the present embodiment, a housing 82G and the housing 82H constituting the first partial illumination optical system IOP1 connected via a bellows-like member 96 _1, housing 82I and the housing 82J
Are connected by a bellows-shaped member 96 ₂ , but each housing constituting the first partial illumination optical system IOP1 is connected to the second partial illumination optical system IO2.
As in the case of P2, they may be connected by an O-ring. That is, in the present embodiment, the first partial illumination optical system IOP1,
It suffices that the connection portion with the second partial illumination optical system IOP2 is connected by the bellows-like member 94.

Further, according to the exposure apparatus 10 of the present embodiment, the illumination optical system IOP is composed of a plurality of optical units having a casing subjected to the chemical clean processing, and a space between the casings which requires the relative displacement is required. Are joined (connected) via an elastic bellows-like member 96 formed of a chemical-clean material, and between the housings that do not require relative displacement allowance, via an O-ring 86 formed of a chemical-clean material. Are joined (fixed). Therefore, the function of each optical unit can be sufficiently exhibited, and the airtightness of the internal space of the housing and the space between adjacent housings can be improved. ) Is purged with a clean nitrogen gas having a concentration of less than 1 ppm, so that the internal chemical cleanliness can be improved, and the adhesion and deposition of cloudy substances on the surface of the optical element such as the internal lens can be suppressed. Absorption of pulsed ultraviolet light (energy beam) by the absorbing gas (oxygen, water vapor, hydrocarbon gas, etc.) in the illumination optical system IOP1 and the second partial illumination optical system IOP2 can be suppressed, thereby irradiating the reticle R and the wafer W. The decrease in the intensity of the ultraviolet pulse light to be performed can be suppressed over a long period of time.

In this embodiment, the movable blade B
L, vibrating mirror 28E, illumination system aperture stop plate 28G, first
Since the actuators for driving the movable members such as the fly-eye lens system 28C are arranged outside the illumination system housing 26A of the first partial illumination optical system IOP (that is, each housing), those actuators are arranged inside the illumination system housing. It is not a source of pollution. Therefore, the degree of chemical cleanness inside can be improved as much as the actuator does not become a contamination source. Also, like the actuator, the sensor does not become a source of contamination inside the illumination system housing. Therefore, the presence of the sensor does not reduce the degree of chemical cleanness in the illumination system housing, and the high accuracy of the actuator based on the sensor output. Control becomes possible, and the position of movable optical members such as the movable blade, the vibrating mirror, the illumination system aperture stop plate, and the first fly-eye lens system can be controlled with high precision.

Further, since the magnetic fluid seal is used for the bearing portions of all the rotating members having the rotating shaft provided in the illumination system housing 26A, the magnetic fluid seal is provided in the gap between the rotating shaft and the bearing portion. And the improvement of the airtightness of the bearing portion and the smooth rotation of the rotating shaft can be realized at the same time. In addition, since the magnetic fluid seal uses a fluorine-based base oil that is a chemically clean substance, it is possible to suppress a decrease in the degree of chemical cleanliness.

In the exposure apparatus of this embodiment, the degree of chemical cleanliness inside the illumination optical system IOP can be improved by the various measures as described above, whereby the pulse ultraviolet light having a wavelength of about 193 nm is exposed. Even when used as an energy beam (exposure light), it is possible to effectively suppress a decrease in transmittance or the like of an optical element in the illumination optical system IOP, and to suppress a decrease in the amount of exposure light irradiated on the wafer surface. In addition, high-precision (high-resolution) exposure using the short-wavelength energy beam and improvement in throughput by shortening the exposure time can be simultaneously realized.

In the above embodiment, the light source is A
rF excimer laser light source, KrF excimer laser light source,
Alternatively, an F ₂ laser light source is used, but the present invention is not limited to this.
A vacuum ultraviolet light source such as a Kr ₂ laser light source of m or an Ar ₂ laser light source of a wavelength of 126 nm may be used. In such cases,
Further improvement of resolution by pulsed ultraviolet light of shorter wavelength,
As a result, exposure with higher precision can be performed.

Further, in the above embodiment, the case where the second partial illumination optical system IOP2 includes only optical elements such as non-movable lenses and mirrors is described, but the present invention is not limited to this. The system may include a movable optical member that is stationary during the exposure operation but is movable during non-exposure. As an example of a movable optical member movable at the time of non-exposure, at least one of each of the relay lens systems 28M, the lens 28L, and the mirror M4 housed in the illumination system housing 26B has its optical axis set to another during the non-exposure operation. This includes the case where it is configured to be drivable with respect to the optical axis of a lens or a mirror. Alternatively, the second partial illumination optical system IOP2 may include a movable part (second movable part) that moves by a smaller amount than the movable blade BL or the like during the exposure operation. Each relay lens system 28M, lens 28L, mirror M described above
4 includes a case where at least one of the movable blades 4 can be driven by a smaller amount than the movable blade BL or the like during the exposure operation.
Even in such a case, the second partial illumination optical system I during the exposure is used.
The vibration of OP2 and the vibration of the exposure main body are clearly reduced as compared with the case where the residual vibration of the first partial illumination optical system IOP1 is transmitted as it is to the second partial illumination optical system IOP2 and the exposure main body.

In the above embodiment, the illumination system aperture stop plate 28G is used as an aperture stop near the exit surface of the second fly-eye lens system 28F as an optical integrator.
Has been described, but an iris diaphragm having a continuously variable numerical aperture may be provided instead. Alternatively, the illumination system aperture stop plate 28G and the iris stop are arranged in the vicinity of the exit surface of the optical integrator, and at least one of the aperture stop and the iris stop on the illumination system aperture stop plate 28G is projected by the optical integrator. A switching device positioned on the surface may be further provided.

In the above embodiment, the first and second illumination system housings 26A and 26B constituting the first and second partial illumination optical systems IOP1 and IOP2 are replaced with a housing for holding one or more optical members. Are sequentially joined via a joining member, and the inside thereof is made airtight with respect to the outside air, and the inside thereof has a clean nitrogen gas (N ₂ ) or helium gas having a concentration of air (oxygen) less than 1 ppm. It is assumed that (He) is filled. However, the present invention is not limited to this, and the first illumination system housing and the second illumination system housing may be integrally molded housings, and the optical members may be provided therein. The arrangement may be the same as in the embodiment, and the nitrogen gas or the like may be purged in each housing. Alternatively, the first and second illumination system housings 26
A and 26B may be covered with another case, and the inside thereof may be filled with clean dry nitrogen gas (N ₂ ) or helium gas (He). That is, the inside of the illumination optical system may be purged in a double structure. When the inside of the illumination optical system is purged in a double structure as described above, different kinds of gases may be used inside and outside the inner housing. For example,
Dry nitrogen gas or helium gas may be used in the inner housing, and dry air (dry air) may be used in the case outside the housing.

Further, in the above embodiment, the case where wafer stage WST is mounted on wafer base surface plate 54 suspended and supported from lens barrel surface plate 44 has been described, but the present invention is not limited to this. However, the present invention can be suitably applied to a scanning type exposure apparatus of a type in which a wafer base is provided separately from a main body column supporting a reticle stage (and a projection optical system PL). However, in this case, since it is necessary to always grasp the relative positional relationship between the main body column and the wafer base platen, for example, a position sensor that measures the positional relationship between the base plate on which the main body column is mounted and the main body column is used. In addition, it is necessary to provide a position sensor for measuring the positional relationship between the base plate and the wafer base platen.

Further, in the above embodiment, the case where the first partial illumination optical system IOP1 (separation gantry 22) is installed on the base rate BP has been described. 22) may be installed on a stand different from the base rate BP, for example, on a concrete block called a pedestal provided in a building of a semiconductor factory.

In the above embodiment, a fly-eye lens is used as an optical integrator (homogenizer). However, a rod integrator may be used instead. In an illumination optical system using a rod integrator, the rod integrator is arranged such that its exit surface is substantially conjugate with the pattern surface of the reticle R. Therefore, for example, the movable blind described above is close to the exit surface of the rod integrator. A movable blade BL of 28J is arranged. Therefore, this illumination optical system is divided into two parts by the rod integrator, and the movable blind is provided in the first portion where the rod integrator is arranged, and the fixed blind is fixed to the main body column, as in the above embodiment. Provided in the second part. In addition,
An illumination optical system using a rod integrator is disclosed in, for example, US Pat. No. 5,675,401. Also,
A fly-eye lens and a rod integrator may be combined, or two rod integrators may be arranged in series to form a double optical integrator.

Further, as in the above embodiment, the lens barrel surface plate 44
Is made of a casting or the like, the lens barrel base 4 is required to hold the lens barrel of the projection optical system PL with high accuracy by the lens barrel base 44.
It is desirable to spray a metal material such as ceramics or stainless steel on a portion of the surface of No. 4 where the flange FLG of the projection optical system PL contacts.

In the above embodiment, the main controller 50
Control the various devices shown on the right side of FIG. 7, but the present invention is not limited to this. Controllers for individually controlling these devices may be provided, or any combination of these may be provided by a plurality of controllers. Alternatively, the control may be performed.

Further, in the above embodiment, the vibration isolating unit 4
Although the case where the active vibration isolator is used as 2A to 42D has been described, it is needless to say that the present invention is not limited to this. That is, these may be passive vibration isolators.

Further, for example, similarly to the above-described embodiment, even in an exposure apparatus using ultraviolet light, a reflection system including only a reflection optical element as a projection optical system or a catadioptric system having a reflection optical element and a refractive optical element is used. A system (catadioptric system) may be employed. Here, as a catadioptric projection optical system, for example, Japanese Patent Application Laid-Open No. Hei 8-171504 (and US Pat. No. 5,668,672 corresponding thereto)
) And a catadioptric system having a beam splitter and a concave mirror as a reflective optical element, or a catadioptric system disclosed in Japanese Patent Application Laid-Open No. 10-20195 (and corresponding US Pat. No. 5,835,275). Kaihei 8-334695
Publication (and corresponding US Pat. No. 5,689,3)
No. 77) and Japanese Patent Application Laid-Open No. 10-3039 (and corresponding US Patent Application No. 873,605 (filing date: June 12, 1997)). Without using a catadioptric system having a concave mirror or the like.

In addition, a plurality of refractive optical elements and two mirrors (a primary mirror which is a concave mirror and a refractive element) disclosed in JP-A-10-104513 (and US Pat. No. 5,488,229). Or a sub-mirror which is a back mirror in which a reflection surface is formed on the side opposite to the incident surface of the plane-parallel plate) and an intermediate image of a reticle pattern formed by the plurality of refractive optical elements. A catadioptric system that re-images on the wafer by the primary mirror and the secondary mirror may be used. In this catadioptric system, a primary mirror and a secondary mirror are arranged following a plurality of refractive optical elements, and illumination light is reflected through a part of the primary mirror in the order of a secondary mirror and a primary mirror. Part to reach the wafer.

The catadioptric projection optical system has, for example, a circular image field, is telecentric on both the object side and the image side, and has a projection magnification of 1/4 or 1/5. A double reduction system may be used. Further, in the case of a scanning exposure apparatus having this catadioptric projection optical system, the irradiation area of the illumination light is substantially centered on its optical axis within the field of view of the projection optical system, and is substantially in the scanning direction of the reticle or wafer. It may be of a type defined in a rectangular slit shape extending along the orthogonal direction. According to a scanning exposure apparatus provided with such a catadioptric projection optical system, for example, a high accuracy 100 Nml / S pattern about fine patterns using a F ₂ laser beam having a wavelength of 157nm as exposure illumination light on the wafer Can be transferred to

As the vacuum ultraviolet light, ArF excimer laser light, F ₂ laser light, or the like is used. In the infrared region oscillated from a DFB semiconductor laser or a fiber laser,
Alternatively, a single-wavelength laser beam in the visible region may be amplified by, for example, a fiber amplifier doped with erbium (or both erbium and yttrium), and a harmonic converted into ultraviolet light using a nonlinear optical crystal may be used. .

For example, the oscillation wavelength of a single-wavelength laser is set to 1.
When the wavelength is in the range of 51 to 1.59 μm, the generated wavelength is 18
An eighth harmonic having a wavelength in the range of 9 to 199 nm or a tenth harmonic having a generation wavelength in the range of 151 to 159 nm is output. Especially the oscillation wavelength is 1.544 to 1.553 μm
m, an 8th harmonic having a generation wavelength in the range of 193 to 194 nm, that is, ultraviolet light having substantially the same wavelength as the ArF excimer laser light is obtained, and the oscillation wavelength is set to 1.57.
When it is within the range of 1.58 μm, the generated wavelength is 157 to
The 10th harmonic within the range of 158 nm, that is, ultraviolet light having substantially the same wavelength as the F ₂ laser light is obtained.

The oscillation wavelength is set to 1.03 to 1.12 μm
, A 7th harmonic whose output wavelength is in the range of 147 to 160 nm is output.
When the wavelength is in the range of 099 to 1.106 μm, a 7th harmonic having a generated wavelength in the range of 157 to 158 μm, that is, ultraviolet light having substantially the same wavelength as the F ₂ laser light is obtained. In this case, as the single-wavelength oscillation laser, for example, an ytterbium-doped fiber laser can be used.

In addition to a micro device such as a semiconductor element, a glass substrate or a mask for manufacturing a reticle or a mask used in an optical exposure apparatus, an EUV exposure apparatus, an X-ray exposure apparatus, an electron beam exposure apparatus, or the like. The present invention is also applicable to an exposure apparatus that transfers a circuit pattern onto a silicon wafer or the like. Here, a transmissive reticle is generally used in an exposure apparatus using DUV (far ultraviolet) light or VUV (vacuum ultraviolet) light, and quartz glass is used as a reticle substrate.
Quartz glass, fluorite, magnesium fluoride, quartz, or the like doped with fluorine is used. In a proximity type X-ray exposure apparatus or an electron beam exposure apparatus, a transmission mask (stencil mask, membrane mask) is used.
And a silicon wafer or the like is used as a mask substrate.

Of course, not only an exposure apparatus used for manufacturing a semiconductor element, but also an exposure apparatus used for manufacturing a display including a liquid crystal display element for transferring a device pattern onto a glass plate, and manufacturing a thin film magnetic head The present invention can also be applied to an exposure apparatus used to transfer a device pattern onto a ceramic wafer, an exposure apparatus used to manufacture an imaging device (such as a CCD), and the like.

In the above embodiment, the case where the present invention is applied to a scanning stepper has been described. However, while the mask and the substrate are kept still, the pattern of the mask is transferred onto the substrate, and the substrate is sequentially stepped. The present invention is also suitably applied to a step-and-repeat type reduction projection exposure apparatus that moves, or a proximity exposure apparatus that transfers a mask pattern to a substrate by bringing a mask and a substrate into close contact without using a projection optical system. You can do it.

When a linear motor (see US Pat. No. 5,623,853 or US Pat. No. 5,528,118) is used for a wafer stage or a reticle stage, air levitation using air bearing is used. Not only the type,
A magnetic levitation type using Lorentz force or reactance force may be used.

The stage may be a tie that moves along a guide, or may be a guideless type without a guide.

Further, the second partial illumination optical system IOP2 comprising a plurality of lenses, the projection optical system PL and the like are mounted on the main body column 14, and the first partial illumination optical system IOP1 is mounted on the separation stand 22, In addition to making adjustments, the reticle stage and wafer stage composed of a large number of mechanical parts are mounted on the main body column, and wiring and piping are connected. The device can be manufactured. It is desirable that the manufacture of the exposure apparatus be performed in a clean room in which the temperature, cleanliness, and the like are controlled.

In the beam matching unit, the lens barrel of the projection optical system PL, and the illumination optical system unit, a tool for inserting a tool for adjusting the position between each unit and the position of an internal optical element is provided. A through hole may be provided. If there is a through-hole, there is a possibility that contaminated air may enter from that part. Therefore, when manufacturing an exposure apparatus, the presence or absence of a through hole for each unit or lens barrel was investigated,
If a through-hole is found, close the through-hole with a material that has low outgassing.

Each unit is composed of a unit main body having a U-shaped cross section for accommodating an optical member, and a panel portion closing an opening of the unit main body. Therefore, a packing similar to the O-ring shown in FIGS. 4 and 5 may be provided between the unit body and the panel portion.

In the semiconductor device, a step of designing the function and performance of the device, a step of manufacturing a reticle based on the design step, a step of manufacturing a wafer from a silicon material, and a step of manufacturing a reticle by the exposure apparatus of the above-described embodiment. Transferring the pattern to the wafer,
It is manufactured through a device assembly step (including a dicing step, a bonding step, and a package step), an inspection step, and the like.

[0146]

As described above, according to the present invention,
There is an unprecedented excellent effect that the influence of the vibration of the illumination optical system during exposure on the exposure main body portion can be reduced and the exposure accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is a view schematically showing an overall configuration of an exposure apparatus according to an embodiment.

FIG. 2 is a diagram showing a specific configuration of the illumination optical system of FIG. 1;

FIG. 3 is a cross-sectional view of the entire second partial illumination optical system IOP2 and a part of the first partial illumination optical system IOP1 constituting the illumination optical system of FIG. FIG.

FIG. 4A is a diagram illustrating an example of O used in the illumination optical system of FIG. 3;
FIG. 4B is a diagram illustrating a cross-sectional shape of the ring, and FIG. 4B is a diagram illustrating a state in which the O-ring in FIG.

5A is a diagram showing a cross-sectional shape of a modified example of the O-ring, and FIG. 5B is a diagram showing a state in which the O-ring in FIG. 5A is crushed.

FIG. 6 is a diagram for explaining a configuration of a condenser lens system 28D of FIG. 2 and a chemical clean measure thereof,
It is sectional drawing which shows the condenser lens system 28D in a simplified manner.

FIG. 7 is a block diagram showing a configuration of a control system of the apparatus shown in FIG.

[Explanation of symbols]

10 Exposure apparatus, 14 Body column (part of exposure main body), 26A First illumination system housing, 26B Second illumination system housing, 28F Second fly-eye lens system (optical integrator), 28G Illumination System aperture stop plate, 32: motor (switching device), 94: bellows-like member (connection part), R: reticle (mask), IOP: illumination optical system, W: wafer (substrate), WST: wafer stage (substrate stage) , Reticle stage (mask stage, part of exposure main body), P
L: projection optical system (part of the exposure main body), BL: movable blade (first movable portion), IOP1: first partial illumination optical system (first partial optical system), IOP2: second partial illumination optical system (Second partial optical system).

Continued on the front page (72) Inventor Hiromitsu Yoshimoto 3-2-3 Marunouchi, Chiyoda-ku, Tokyo F-term in Nikon Corporation (reference) 5F046 AA22 AA23 BA05 CA03 CA04 CA05 CB05 CB08 CB13 CB20 CB23 CB25 DA01 DA02 DA27 DB01 DC02

Claims (8)

[Claims] An illumination optical system for illuminating a mask on which a predetermined pattern is formed with an energy beam, and an exposure main body including at least a substrate stage for holding a substrate exposed by the energy beam emitted from the mask. An exposure apparatus comprising: a first partial optical system including a first movable unit movable during an exposure operation, wherein the illumination optical system is movable by an amount equal to or more than a movable amount of the first movable unit during the exposure operation; And a second partial optical system that does not include a movable part to be installed, the second partial optical system is installed on the exposure main body, and the first partial optical system is installed separately from the exposure main body. Exposure apparatus characterized by the above-mentioned. 2. The exposure apparatus according to claim 1, wherein the second partial optical system includes only an optical member that is stationary during the exposure operation. 3. The apparatus according to claim 1, wherein the second partial optical system includes a second movable section that is movable by a smaller amount than the first movable section during the exposure operation. Exposure apparatus according to the above. 4. The illumination system according to claim 1, wherein the first partial optical system and the second partial optical system each include an illumination system housing that separates the interior from the outside air and makes the interior airtight. The exposure apparatus according to claim 1. 5. A space between a first illumination system housing constituting the first partial optical system and a second illumination system housing constituting the second partial optical system is separated from the outside air to be airtight. , The first illumination system housing and the second
The exposure apparatus according to claim 4, further comprising a connection unit that connects the illumination system housing to the illumination system housing in a state where transmission of vibration between the illumination system housing and the illumination system housing is restricted. 6. The exposure apparatus according to claim 5, wherein the connection portion is formed of a bellows-shaped member that can be extended and contracted. 7. The first partial optical system includes an optical integrator, at least one of an illumination system aperture stop plate having at least one aperture stop arranged near an exit surface of the optical integrator, and at least one of an iris stop. The first movable unit further includes a switching device that positions one of the aperture stop and the iris stop of the illumination system aperture stop plate on the exit surface of the optical integrator. Item 1. The exposure apparatus according to Item 1. 8. The exposure apparatus according to claim 1, wherein the first movable section is a movable blade that limits an irradiation area of the energy beam on the mask during exposure.