JPH0511436A - Mask correcting method and device and mask used for this method - Google Patents

Abstract

PURPOSE:To easily correct the defects on a phase shifter with high accuracy by adjusting the refractive index at the desired point on the phase shift mask. CONSTITUTION:The defect 5 on the phase shifter 4 of the mask provided with light shielding patterns 3 and the phase shifters 4 on a transparent conductive layer 2 formed on a transparent substrate 1 as an example of the phase shift mask is irradiated with a focused ion beam 6 to form an ion implanted layer 7 and to change the density of the defect part, i.e., refractive index, by which the phase difference of the transmitted light generated by the defect is made zero.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mask repairing method for a projection optical system mask, a mask repairing apparatus and mask used therefor, and more particularly to a phase shift mask provided with a phase shifter having a predetermined pattern on a transparent substrate. The present invention relates to a mask correction method, a mask correction device and a mask used for the same.

[0002]

2. Description of the Related Art With the increasing integration of semiconductors, a phase shift mask has been put into practical use in order to expose a finer pattern at a low cost. An example of this phase shift mask is shown in FIG. In the figure, 1 is a transparent substrate, 2 is a transparent conductive layer on the transparent substrate 1, a light-shielding pattern 3 for forming a circuit pattern is provided on the transparent conductive layer 2, and a phase shifter 4 is planned to form a circuit pattern. They are provided alternately on the area. Then, as shown in FIG. 14A, since the light transmitted through the phase shifter 4 is out of phase with the light transmitted through the adjacent pattern by π, high-resolution exposure is possible due to light interference at the pattern boundary. It is supposed to become.

However, if there is a defect 5 on the phase shifter 4 as shown in FIG. 14 (b), the phase amplitude of the light transmitted through the defective portion is largely deviated, and the defect is directly transferred onto the element. . Therefore, repairing this defect is one of the important issues in the practical application of the phase shift mask. For example, Nikkei Micro Devices 19
On December 66, 1990, p. 66, "Phase shift in which elemental technologies for practical use such as inspection, modification, negative resist, etc. have begun to appear" discloses practical use and inspection / correction technology of a phase shift mask.

[0004]

If the defect on the phase shifter 4 shown in FIG. 14 (b) is simply removed by machining or the like, the phase amplitude of the transmitted light is further deviated, and the defect is corrected. I won't. An example of a correction method for solving this problem is shown in the above report article, and this correction method will be briefly described with reference to FIG. As shown in FIG. 15A, the structure of the phase shift mask is a two-layer shifter structure in which the patterned phase shifter 4 is further placed on the sub-phase shifter 8 having a phase difference π deposited on the entire surface of the mask. There is. When there is a defect 5 on the phase shifter 4, both the phase shifter 4 and the sub-phase shifter 8 including the defective portion are removed as shown in FIG. Point 9
Since the total phase of 2 is shifted back by 2π, the defect has been repaired.

Here, the thickness d of the phase shifter 4 having the phase difference π is expressed by the equation (1) in FIG. For example, substituting the wavelength of i-line λ = 365 nm and the refractive index of SiO ₂ n≈1.5 results in d≈365 nm. Therefore, the phase difference of 1
When the correction is performed with an accuracy of 0% or less, the above-described correction processing depth accuracy needs to be as high as ± several tens of nm or less, but such high-precision local processing is not easy. Further, in the conventional correction method of FIG. 15, if the sub-phase shifter 8 has a defect, the correction becomes difficult.

On the other hand, a method of filling the defective portion of the phase shifter with local film formation has been proposed, but the accuracy required for the film formation thickness is ± several tens of nm, which is the same as during processing, and again,
Such highly accurate local film formation is not easy.

Further, in JP-A-60-170938, the substrate portion corresponding to the pattern defect portion is irradiated with an ion beam to form a minute ion implantation area or a minute ion milling area on the substrate portion. Has been disclosed in which the defect of the light-shielding pattern of the mask is corrected by causing a change in the optical scattering characteristics of the mask. However, this is not a correction method for the phase shifter that is a transparent pattern, but it makes the defect part have a light-shielding property by minute scattering, and it cannot be practically applied to the defect of the phase shifter of a size that usually occurs. Moreover, it is not possible to perform accurate correction according to the shape of the phase shifter defect (shape of the depression).

The present invention has been made in view of the above points,
The object of the present invention is to provide a mask repairing method and a device for carrying out the mask repairing method, which can repair defects on the phase shifter of the phase shifter mask with high accuracy and convenience.

[0009]

The defect on the phase shifter becomes a problem because the phase amplitude of the light transmitted through the defective portion is deviated. Therefore, in order to correct the defect, the phase difference generated in the defective part with respect to the normal part may be set to zero. The above-mentioned purpose of performing this phase difference correction more simply is not to physically change the optical path length of the defective portion by processing or film formation, but to locally change the refractive index of the defective portion to transmit the transmitted light. This is achieved by correcting the phase difference.

That is, in addition to the above-mentioned prior application, an example in which impurities are implanted by ion beam irradiation to change the refractive index in the optical path of the optical fiber at the central portion and the outer peripheral portion, or flat SiO by irradiation of excimer laser light is used. An example of observing the lens effect by causing thermal distortion of Gaussian distribution on ₂ has been reported. Therefore, in the present invention, focusing on these changes in the refractive index caused by the irradiation of the ion beam or the laser beam, the defect portion of the phase shifter is irradiated with the energy beam to change the refractive index to correct the defect.

[0011]

When the transparent material is irradiated with the ion beam, the density of the material is changed and the refractive index is changed due to the effect of implanting impurities. The condition for irradiating the defective part of the phase shifter with a focused ion beam to correct the phase difference is considered. Assuming that the depth of the dent in the defective portion is d ₀ , the refractive index of the original material is n, the thickness of the ion beam implanted layer is d _i , and the refractive index of the ion beam implanted layer is n _i , the defect in the normal portion is The condition for making the phase difference of the part zero by the ion beam irradiation is represented by the equation (2) in FIG. Therefore, by controlling d _i by the acceleration energy of the focused ion beam and n _i by the current density, the defect can be repaired by satisfying the expression (2).

When a transparent material is irradiated with laser light of sufficient power, the density of the material changes due to thermal strain, and the refractive index changes. The conditions for irradiating the defective portion of the phase shifter with laser light to correct the phase difference can be considered in the same manner as in the case of using the focused ion beam. Let d _{0 be} the depth of the dent in the defect, n be the refractive index of the original material, d _{e be} the thickness of the thermal strained layer due to laser irradiation, and n _e be the thermal strained layer's refractive index. The condition of is expressed by equation (3) in FIG. Therefore, when using a pulsed laser beam, by the pulse width and laser power controlling the d _e and n _e, it can correct defects by satisfied likewise (3).

[0013]

Embodiments of the present invention will be described below with reference to the drawings. <First Embodiment> As a first embodiment of the present invention, a method of collectively irradiating a defect of a phase shifter with a focused ion beam to correct the defect will be described with reference to FIG. In the figure, 1 is a transparent substrate, 2 is a transparent conductive layer, 3 is a light-shielding pattern, 4 is a phase shifter, and 5 is a defect of the phase shifter. As shown in FIG. 1A, when the phase shifter 4 has a defect 5, the phase amplitude of the light transmitted through the defect portion largely shifts, as described above. Therefore, in this embodiment, the focused ion beam 6 is shaped into the shape of the defect 5 and the defective portion is collectively irradiated. At this time, most of the defects have a dish-like shape in which the depth d _{0 of the} recess increases toward the center.

Here, if the above equation (2) for the condition of phase difference correction by ion beam irradiation is modified, (4) in FIG.
The formula is obtained. Now, the acceleration energy is almost constant within the beam diameter of the focused ion beam 6, and therefore the depth d _i of the ion implantation layer 7 is also constant. On the other hand, the current density within the beam diameter has a Gaussian distribution, and the refractive index n _i of the ion implantation layer 7 depending on the impurity concentration increases toward the center of the beam. This acts in the direction of canceling the defect shape in which the depth d ₀ increases toward the center, and the correction condition of the equation (4) can be almost satisfied within the entire defect (within the beam diameter). From the above, by only irradiating the defect 5 with the focused ion beam 6 at once, the phase difference of the defect can be corrected as shown in FIG.

As a method of shaping the focused ion beam 6 into the shape of the defect 5, there are a method of focusing and projecting an image of the variable slit aperture, and a method of electrically shaping the image by the voltage applied to the deflector stigma electrode.

<Second Embodiment> As a second embodiment of the present invention, FIG. 2 shows a method for correcting defects by scanning a focused ion beam 6 which is narrowed down and irradiating the defects 5 of the phase shifter 4 with reference to FIG. Explain. As shown in FIG. 2A, when the defect 5 on the phase shifter 4 is large and the distribution of the depth d ₀ of the defect 5 is asymmetric, the correction by the first embodiment is difficult. Therefore, in this embodiment, the focused ion beam 6 narrowed down sufficiently to the size of the defect 5 is scanned and irradiated on the defect 5. At this time, the in-plane distribution of the defect depth d ₀ , the depth d _i of the ion-implanted layer 7 at the time of repair, and the in-plane distribution of the refractive index n _i are respectively d ₀ (x, y), d _i (x, y), Assuming that _ni (x, y), the correction condition is (5) in FIG.
It is represented by a formula.

Here, if the acceleration energy is made constant in order to keep the beam diameter constant, then d _i (x, y) = d _i becomes constant. Further, n _i is the impurity concentration, that is, the irradiation ion amount D
Since n _i = f (D), the condition required for the in-plane distribution D (x, y) of the irradiation ion amount D is expressed by the formula (6) of FIG. 13 from the formula (5). Be done. here,
The relation n _i = f (D) (monotonic increase) between n _i and D is previously obtained by an experiment using a standard sample. When the defect is repaired, the defect depth distribution d ₀ is determined by the optical interference method or the like.
(X, y) is measured, the irradiation ion dose distribution D (x, y) required for correction is calculated using the equation (6), and the calculated D (x, y
Irradiate the focused ion beam 6 according to y). As a result, the phase difference of the defective portion can be corrected as shown in FIG.

Here, as a method for setting the above D (x, y), the fact that the focused ion beam amount D is proportional to the staying time, that is, inversely proportional to the scanning speed v, is used to obtain D.
The scanning speed v at each point in the defect may be set so as to be inversely proportional to (x, y). When the change in beam diameter can be ignored, the beam current value at each point may be set so as to be proportional to D (x, y). As a method for setting the beam current value, there is a method using a variable aperture or a zoom lens.

Next, an apparatus configuration for carrying out this embodiment will be described with reference to FIG. In the figure, 10 is an ion source, 11 is an extraction electrode, 12 is a converging lens, 13 is a blanking electrode, 14 is a blanking aperture, 15 is a converging lens, 16 is a deflector stigma electrode, 17 is a laser oscillator, and 18 is an optical path. Extended separator, 19 is a parabolic mirror, 20 is a phase shift mask, 21 is a stage, 22 is an imaging lens, 23 is an interference light intensity detector, 24 is an ion beam chamber, 25 is an ion beam power source, and 26 is An ion beam deflection controller, 27 is a system controller that controls the entire system.

In the above structure, the ion beam 6 extracted from the ion source 10 is focused by the focusing lenses 12 and 15 at the front and rear stages, and the phase shift mask 20 is obtained.
Irradiate on. At this time, the voltage applied to the blanking electrode 13 turns the beam on and off, and the voltage applied to the deflector stigma electrode 16 shapes the beam shape and sets the scanning speed. Further, the acceleration energy setting, the focused beam diameter setting, and the beam current value setting when the focusing lens in the front or rear or the rear stage is a zoom lens are all set by the voltage applied from the ion beam power source 25 to each electrode.

On the other hand, the laser light oscillated from the laser oscillator 17 is separated into two by the optical path expansion separator 18, and this is imaged on the phase shift mask 20 by the parabolic mirror 19. Then, the two lights transmitted through the phase shift mask 20 are imaged again by the imaging lens 22, and the interference light intensity is detected by the detector 23. Thereby, the refractive index of a desired portion on the phase shift mask 20 can be indirectly measured. Further, by irradiating the defect portion and the normal portion on the mask with two separated laser beams and causing the transmitted light to interfere with each other, the phase difference correction of the defect according to the present invention can be monitored. Moreover, by interfering irradiated with laser light separated into two portion irradiated and non-irradiated portion of the ion beam the transmitted light, it can be measured n _i and D relationship n _i = f (D).

As a method of irradiating the mask with the laser light, a method of converging and irradiating the mask obliquely by using an ordinary imaging lens, or a reflecting objective in which an optical path is bent by a reflecting mirror provided on the optical axis of the ion beam is used. A method of collecting and irradiating from directly above with a lens or the like may be used.

<Third Embodiment> As a third embodiment of the present invention, a method of correcting defects by combining machining with a focused ion beam and implantation will be described with reference to FIG. When the defect 5 on the phase shifter 4 is large and the unevenness is severe, it is not easy to set the irradiation ion amount distribution D (x, y) in the second embodiment with high accuracy. Therefore, as shown in FIG. 4A, first, the focused ion beam 6 is irradiated to the defective portion while the etching gas 29 is supplied from the nozzle 28 to etch the phase shifter of the defective portion with respect to the lower layer with high selectivity. . For example, the material of the phase shifter 4 is SiO.
_{2. When} the material of the transparent conductive layer 2 is In ₂ O ₃ , XeF ₂ may be used as an etching gas. And then, in FIG.
4B, the transparent conductive layer 2 is irradiated with a focused ion beam to form an ion-implanted layer 7 as shown in FIG. 4C to correct the phase difference. At this time, the corrected portion is already flattened, and the irradiation ion amount D becomes a uniform condition in the plane, so that the setting is easy. In the present embodiment that adopts such a method, it is necessary to change the energy of the focused ion beam from low acceleration to high acceleration during processing and during implantation, but focusing is performed so as to suppress the accompanying change in beam diameter. Control the system. The above-described etching process may be performed up to the transparent conductive layer 2 and then the transparent substrate 1 may be implanted to correct the defect. In addition, in the processing shown in FIG. 4A, the convex portion is processed first and the bottom surface of the processed portion tends to be flattened. Therefore, the processing is performed when the bottom surface of the defect 5 becomes sufficiently gentle. Then, the defect may be corrected by using the method according to the second embodiment.

FIG. 5 is a diagram showing an apparatus configuration for carrying out this embodiment. The apparatus shown in the figure is similar to the apparatus shown in FIG. 3 except that a gas cylinder 30, a valve 31, and a gas supply system are provided.
A flow rate control device 32 and a nozzle 28 are added.
As a result, the etching gas can be supplied at the same time as the irradiation of the focused ion beam 6 to locally etch the defective portion. Note that other configurations and functions are the same as those of the device shown in FIG.

<Fourth Embodiment> As a fourth embodiment of the present invention, a method of collectively irradiating a large area of a mask with a shower type ion beam to correct a film thickness defect such as a phase shifter will be described with reference to FIG. Explain. As shown in FIG. 6A, when the film thickness of the phase shifter 4 is uniformly insufficient,
The phase amplitude of the transmitted light also deviates uniformly from the normal state (dotted line in FIG. 6A). For example, the normal state π
If the film thickness becomes π / 4 due to insufficient film thickness with respect to / 2, it will not completely cancel out with the transmitted light (phase −π / 2) of the adjacent pattern at the boundary, which may cause deterioration in resolution and defective pattern width. Become. Therefore, the shower-type ion beam 33 is collectively radiated to form the ion-implanted layer 7 on the entire wide area including the defective film thickness portion as shown in FIG. 8B. In the ion-implanted layer 7, the refractive index increases, and FIG.
As indicated by the white arrow in (a), the transmitted light of the phase shifter 4 has the effect of increasing the amplitude, and the transmitted light of the adjacent pattern has the effect of decreasing the amplitude (the phase deviates from -π / 2).

Therefore, the interference light intensity of the transmitted light of the phase shifter 4 part and the transmitted light of the part without the phase shifter 4 is monitored, and the irradiation of the ion beam 33 is stopped and corrected at the time point when the transmitted lights completely cancel each other out. To complete. In the above example, the phase of the transmitted light of the phase shifter 4 is π / 4 to 3π / 8.
And the point at which the phase of the transmitted light of the adjacent pattern changes from −π / 2 to −3π / 8 is the completion point of the correction. At this time, adjacent transmitted lights completely cancel each other at the boundary, so that a desired high-resolution pattern transfer can be performed.

When the film thickness of the phase shifter 4 varies gently in the mask, for example, the plasma distribution in the bucket type ion source is controlled by a magnet,
The current density distribution of the ion beam to be irradiated can be set so as to cancel the above film thickness variation, and the entire mask surface can be collectively corrected. Further, the present embodiment can be applied in exactly the same manner even when the film thickness of the transparent substrate 1 or the transparent conductive layer 2 is defective.

<Fifth Embodiment> As a fifth embodiment of the present invention, a method of collectively irradiating the defects of the phase shifter with focused laser light will be described with reference to FIG. The present embodiment is a modification method using a focused laser beam instead of the focused ion beam in the first embodiment. As shown in FIG. 7A, the focused laser beam 34 is shaped into the shape of the defect 5 and the defective portion is collectively irradiated. When the equation (3) of FIG. 13 which is the condition for the phase difference correction by laser light irradiation is modified, the equation (7) of FIG. 13 is obtained. The thermal diffusion time is substantially constant within the diameter of the focused laser beam, and the depth d _e of the thermal strain layer 35 is also substantially constant. On the other hand, the power density within the beam diameter has a Gaussian distribution, and the refractive index n _{e of} the thermal strain layer 35 depends on the magnitude of thermal strain.
Becomes larger toward the center of the beam. Therefore, similarly to the first embodiment, it is possible to irradiate the defect 5 with the focused laser beam 34 all at once.
It is possible to correct the phase difference of the defective portion as shown in FIG.

As a method of shaping the focused laser beam 34 into the shape of the defect 5, there are a method of converging and projecting an image of a variable slit and a method of using a cylindrical lens.

<Sixth Embodiment> As a sixth embodiment of the present invention, a method of scanning and irradiating a defect of a phase shifter with laser light which is narrowed down and correcting the defect will be described with reference to FIG.
The present embodiment is a correction method using a focused laser beam instead of the focused ion beam in the second embodiment. As shown in FIG. 8A, the defect 5 is scanned and irradiated with a laser beam 34 that is sufficiently narrowed to the size of the defect 5. At this time, the defect depth d ₀ , the depth d _e of the thermal strain layer 35 at the time of repair,
Assuming that the in-plane distribution of the refractive index n _e is d ₀ (x, y), d _e (x, y), and n _e (x, y), the correction conditions are shown in FIG. 8)
It is represented by a formula.

Assuming that the laser pulse width is constant, d
_e (x, y) = a d _e constant. Since n _e depends on the magnitude of thermal strain, that is, the laser power P, n _e = g
If (P) is set, the in-plane distribution P (x,
The condition required for y) is expressed by equation (9) in FIG. 13 from equation (8). Note that the relationship between n _e and P n _e = g
(P) (monotonic increase) is previously obtained by an experiment using a standard sample. Then, when correcting the defect, the defect depth distribution d ₀ (x, y) is measured by an optical interference method or the like,
Laser power distribution P required for correction using equation (9)
(X, y) is obtained, and laser light is irradiated according to the obtained P (x, y), whereby the phase difference of the defective portion can be corrected as shown in (b) of FIG. Where P
(X, y) can be set using a variable transmittance filter provided in the middle of the laser optical system.

An apparatus configuration for carrying out this embodiment is shown in FIG.
Shown in. In the figure, 36 is a correction laser oscillator, 3
7 is a shutter, 38 is a variable transmittance filter, 39 is XY
A scanner, 40 is a converging lens, and 41 is a system controller that controls the overall control. The same components as those in the above-described configuration of FIG. 3 are designated by the same reference numerals. The laser light 34 output from the correction laser oscillator 36 passes through the transmittance variable filter 38 to set the laser power,
The phase shift mask 20 is converged by the focusing lens 40.
It is focused and illuminated on top. At this time, the XY scanner 39 (polygon mirror, galvanometer mirror, etc.) provided on the way is used to move the laser beam 3 to a desired position on the phase shift mask 20.
It is possible to irradiate 4 or to scan on the mask arbitrarily. The monitor laser light oscillated from the laser oscillator 17 is imaged on the phase shift mask 20,
Further, the system for detecting the transmitted interference light by the detector 23 is the parabolic mirror 19 in the device of FIG.
Other configurations and functions only was changed to 0 is quite similar, using this system, and monitoring the phase difference correction of defects according to the present invention, determining the relationship between n _e and P n _e = g (P) It can be performed.

<Seventh Embodiment> As a seventh embodiment of the present invention, a method of correcting defects by combining etching with focused laser light and heat irradiation will be described with reference to FIG. The present embodiment is a correction method using a focused laser beam instead of the focused ion beam in the third embodiment. (A) of FIG.
First, as shown in FIG.
The focused laser beam 34 is irradiated while supplying the laser light to etch the phase shifter in the defect portion with respect to the lower layer with good selectivity. Next, the transparent conductive layer 2 is irradiated with the focused laser beam 34 to form the thermal strain layer 35, and the phase difference is corrected. In the present embodiment, it is necessary to change the power of the focused laser light from low output to high output during etching and formation of the thermal strain layer.

An apparatus configuration for carrying out the present embodiment is shown in FIG.
Shown in 1. In the apparatus shown in the figure, a gas cylinder 30, a valve 31, a flow rate control device 32, and a nozzle 28 are added to the apparatus shown in FIG. 9 as a gas supply system, and the phase shift mask 20 is further housed in a chamber 24. The configuration is such that the etching gas is exhausted by an exhaust system (not shown). Thereby, the etching gas is supplied to the surface of the phase shift mask 20 at the same time as the irradiation of the focused laser beam 34,
The defective portion can be locally etched. Other configurations and functions are similar to those of the device shown in FIG.

<Eighth Embodiment> As an eighth embodiment of the present invention, a method of collectively irradiating a wide region of a mask with a wide laser beam or heating light of a lamp or the like to correct a film thickness defect such as a phase shifter. Will be described with reference to FIG. The present embodiment is a correction method using laser light or heating light instead of the ion beam in the fourth embodiment.

That is, in the fourth embodiment, the shower type ion beam is irradiated to form a uniform ion-implanted layer to increase the refractive index. 12), the uniform thermal strain layer 3 as shown in FIG.
5 is formed to increase the refractive index. The principle of correcting the film thickness defect by uniformly increasing the refractive index is the same as in the fourth embodiment.

Although laser light or heating light was used as the heating beam for forming the thermal strained layer in the fifth to eighth embodiments, the same operation can be performed using an electron beam. .

[0038]

As described above, according to the present invention, the refractive index at a desired position on the phase shift mask can be adjusted easily and accurately, so that the defect on the phase shifter can be corrected with high accuracy and easily. It is possible and its value is great in the field of semiconductor manufacturing using a phase shift mask.

[Brief description of drawings]

FIG. 1 is an explanatory diagram schematically showing a correction method according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram schematically showing a correction method according to a second embodiment of the present invention.

FIG. 3 is an explanatory view showing in simplified form an example of a correction device for carrying out the correction method of the second embodiment of the present invention.

FIG. 4 is an explanatory diagram schematically showing a correction method according to a third embodiment of the present invention.

FIG. 5 is an explanatory view showing a simplified example of a correction device for carrying out the correction method of the third embodiment of the present invention.

FIG. 6 is an explanatory diagram schematically showing a correction method according to a fourth embodiment of the present invention.

FIG. 7 is an explanatory diagram schematically showing a correction method according to a fifth embodiment of the present invention.

FIG. 8 is an explanatory diagram schematically showing a correction method according to a sixth embodiment of the present invention.

FIG. 9 is an explanatory view showing a simplified example of a correction device for carrying out the correction method of the sixth embodiment of the present invention.

FIG. 10 is an explanatory diagram schematically showing a correction method according to the seventh embodiment of the present invention.

FIG. 11 is an explanatory view showing a simplified example of a correction device for carrying out the correction method of the seventh embodiment of the present invention.

FIG. 12 is an explanatory diagram schematically showing a correction method according to an eighth embodiment of the present invention.

FIG. 13 is an explanatory diagram showing a list of mathematical expressions used in the description of the present invention.

FIG. 14 is an explanatory diagram schematically showing the appearance of defects in the phase shift mask.

FIG. 15 is an explanatory diagram schematically showing a conventional correction method.

[Explanation of symbols]

1 transparent substrate 2 Transparent conductive layer 3 light-shielding pattern 4 phase shifter 5 defects 6 Focused ion beam 7 Ion implantation layer 8 sub phase shifter 9 Modifications due to removal 10 Ion source 12,15 Focusing lens 13 Blanking electrode 16 deflector stigma electrode 17 Laser oscillator 18 Optical path expansion separator 19 Parabolic mirror 20 Phase shift mask 21 stages 22 Imaging lens 23 Interfering light intensity detector 25 Ion beam power supply 26 Ion beam deflection control device 27,41 system controller 28 nozzles 32 Flow control device 33 Shower type ion beam 34 Focused laser light 35 heat strain layer 36 Correction laser oscillator 38 Variable Transmittance Filter 39 XY scanner 40 Focusing lens 42 Wide laser light (heating light)

Claims (11)

[Claims] 1. A correction method for a projection optical system mask including a phase shifter having a predetermined pattern formed on a transparent substrate, wherein a refractive index of a defect region of the phase shifter is changed. How to modify the mask. 2. A method for repairing a mask for a projection optical system, comprising a phase shifter having a predetermined pattern provided on a transparent substrate, wherein a defective portion of the phase shifter is removed by etching and then the removed region is removed. A method for repairing a mask, characterized in that the refractive index of a transparent conductive layer region or a transparent substrate region on the transparent substrate corresponding to the above is changed. 3. A correction method for a mask for a projection optical system, comprising a phase shifter having a predetermined pattern provided on a transparent substrate, wherein a defect portion of the phase shifter is formed to a film thickness at which the defect portion becomes substantially flat. After etching, the mask correction method is characterized in that the refractive index of the phase shifter in the defect region which is substantially flattened is changed. 4. A correction method for a mask for a projection optical system including a phase shifter having a predetermined pattern provided on a transparent substrate, wherein the refractive index of the phase shifter and the transparent conductive layer on the transparent substrate are simultaneously changed. A method for correcting a mask characterized by the above. 5. The mask correction method according to claim 1, wherein the change of the refractive index is performed by irradiating a desired region with an ion beam and implanting ions. 6. The method according to any one of claims 1 to 4, wherein the refractive index is changed by irradiating a desired region with a thermal energy beam such as a laser beam or an electron beam to cause thermal distortion. How to fix the mask. 7. An energy beam source for generating an energy beam such as an ion beam, a laser beam, an electron beam, a focusing optical system, a stage, an exposure light irradiation system, an exposure light detection system, and drive control thereof. A mask repairing apparatus for a mask for a projection optical system, comprising a controller and a phase shifter having a predetermined pattern provided on a transparent substrate, wherein a desired region of the mask on the stage is irradiated with an energy beam. In addition, the mask correction device is characterized in that the refractive index of the desired region of the mask with respect to the exposure light is measured. 8. The mask repairing apparatus according to claim 7, further comprising means for shaping and irradiating a desired area of the mask on the stage with the shape of the energy beam. 9. A means for irradiating a desired region of the mask on the stage with a beam of energy as defined in claim 7, and means for irradiating the energy beam by scanning, and a scanning speed or a beam intensity within the scanning region. A mask correction device, characterized in that it is provided with a setting means. 10. The mask correction apparatus according to claim 7, further comprising means for collectively irradiating the energy beam onto a relatively wide area of the mask on the stage. 11. A mask for a projection optical system, comprising a phase shifter having a predetermined pattern for giving a phase difference to a predetermined transmitted exposure light on a transparent substrate, wherein the phase shifter or the transparent conductive layer of the transparent substrate or A mask, wherein the refractive index of at least a part of the transparent substrate is changed.