JPS5950522A - Projection and exposure device - Google Patents

Abstract

PURPOSE:To detect the existence of a foreign matter by a method wherein paralllel light irradiates the surface of a reticle and irregularly reflected light is detected. CONSTITUTION:The pattern of the reticle 1 forming the prescribed pattern is projected to be exposed on a wafer 2. The wafer 2 is put on an X-Y table 7, and the reticle pattern is exposed in a checkered pattern. A foreign matter detecting optical system 14 takes out the light of a light source a half-mirror 15 provided on a shutter 13, and the reticle 1 is irradiated from the parallel direction with the surface thereof. A sensor 22 detects irregularly ly reflected light from the place generating the foreign matter or a crack, and enables detection of the existence of foreign matter, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a projection exposure apparatus suitable for use as a semiconductor device manufacturing apparatus.

IJ Sogerahuie, which is one of the main components of semiconductor device manufacturing, is an exposure device that projects patterns on reticles and masks. At this time, if there is foreign matter attached to the surface of the mask, it will be imaged onto the wafer and exposed, so-called. Hattern defects occur. In particular, when a reticle or mask pattern is exposed on a wafer in a step-and-repeat manner, defects in foreign object images may occur in each element, which is fatal.

For this reason, it is necessary to detect the sound of foreign objects attached to the reticle or mask and remove them, but conventional detection devices cannot fully satisfy this problem.

In recent years, the most advanced method is to irradiate the six outer surfaces of the reticule with a laser beam just before setting the reticle or mask (hereinafter referred to as reticle) in the projection exposure device. A reticle IJ i+++' (r) is used to detect AA''0IJk by scanning the reticle IJ i+++' (r) with its reflected light metal element, and by detecting changes in the amount of reflected light.

However, in this device, after detecting a foreign object, the exposure device
/There is a major problem in that it is not possible to detect all foreign substances that newly adhere when setting the particle or continuing exposure. Another problem with this song is that the device mechanism, such as the laser scanning device and the photoelectric element that follows it, is extremely complex and expensive.Also, detection noise due to the reticle pattern easily enters, while the crank on the reticle surface is completely detected. It is difficult to distinguish between harmless foreign objects on the back side of the reticle and foreign objects on the front side.

Therefore, an object of the present invention is to be able to accurately detect harmful foreign matter adhering to a reticle in an actual exposure state and cracks in the reticle, and to reduce the overall noise and noise of the detection unit while reducing the overall cost. An object of the present invention is to provide a projection exposure system Kk that can be manufactured.

In order to achieve such objects, the present invention provides a method for detecting foreign objects in which a portion of the light source light for projection exposure is guided to the side of the reticle and irradiated approximately parallel to the surface of the reticle, and imaging of the reticle pattern is provided. It can be temporarily installed at a certain position and the diffused reflection of the light r
The light that shines on the surface of the screen is a friend of mine.

The present invention will now be explained with reference to the illustrated embodiments.

Figure 1 is an overall configuration diagram of the projection exposure system (q) of the present invention.
1 is a reticle formed on the surface (F surface) of a predetermined pattern 72, and 2 & Y is a wafer to be exposed by projection of this 1/ticle pattern. This ueno-2 is placed on an XY table 7 consisting of an exposed to light.

The MtJ reteleticle projection optical system 8 is equipped with a reflector 9 in the form of a mirror surface and a 10-year-old fCC copper steel lamp as a light source. A reduction imaging lens 12 is provided so that a notch image of the reticle 1 can be formed on the lateral surface of the wafer 2.

J3 is a shutter that opens and moves during exposure.

On the other hand, 14 is a different* detection optical system, and the shutter 13
A part of the light from the light source is taken out to the side by a top mirror 15 provided directly above the light source. In addition, this optical system 14
are two relay lenses 16, ]7 and a reflecting mirror 18, respectively.
．． 19 and the half mirror 15i/trowel take out the light sound to a side position of the reticle 1, and then irradiate the reticle 1 from a direction substantially parallel to its red face.

A reflecting mirror 20 is provided upright on the other side of the reticle 1 to reflect the sound of the parallel irradiated light so that the irradiation field is parallel to the surface of the reticle 1 again. 21 is a reflection mirror 190 angle changing mechanism.

On the other hand, an optical sensor 22 consisting of a 7-section optical element is attached to a position near Ueno 2 on the XY table 7.

By moving the XY table 7, the reticle can be moved to the imaging position of the turn image.
2 holds its photodetecting surface at the same level as the surface of the wafer 20.

The X and Y table driving mechanisms 3.4, the reflecting mirror angle changing mechanism 21. Optical sensor 22 Total control section 23
The signals are input to the control unit 23, and the control unit 23 outputs them to the calculation unit 24 and outputs them to the 0RT.
25 or printer 26 to indicate the state of the foreign object 'kP.

According to the projection exposure apparatus having the above configuration, detection of foreign matter on the reticle and exposure are carried out as follows.

First, 10 upper and lower mercury lamps set on the reticle It are set at the illustrated positions are turned on, and the shutter 13 is fully opened. At this time, a standard plate is placed on the XY table 7 instead of the wafer, and the entire reduction imaging lens 12 is adjusted so that the reticle pattern image is focused on this red surface. After completing this preparation process, the shutter 13' is closed and the foreign object inspection sound is started.

When the shutter 13 is closed, the light from the lamp 10 is reflected laterally by the half mirror 1-5, and the relay lens 16
．． Reticle l 9 by 17 and reflective mirror 18.19
111 You will be guided in the direction. If the angle of the final reflecting mirror 19 is adjusted appropriately by the full angle changing mechanism 21, the reflected light is irradiated approximately parallel to the surface of the reticle 1 (it may have a slight angle).

Further, a part of the light is reflected by a reflection mirror 20 provided on the opposite side, which is a yc plane or a curved surface, and is then irradiated onto the reticle surface and the side surface of the glass substrate of the reticle.

While holding the anvil in this state, as shown in Figure 2,
The seven Y-tables are moved together and the processor 22 is moved sequentially to various positions within the corresponding position. Then, foreign matter X1. Since light is diffusely reflected at the location where X2 and crank X3 occur, the photon sensor 22 is at the position [Pt x
At P8, it detects the diffusely reflected light and sound of foreign objects X1, X2 and crank X3, thereby making it possible to detect foreign objects and cranks.In this case, the reticle glass surface side where foreign object X2 is located is detected. Of the foreign objects in the pattern 1a, the foreign objects above the pattern 1a are harmless and do not need to be detected.In addition, if a shank 27i like a false rib is provided so that the light is irradiated only on the front surface of the reticle, the back surface It is also possible to not detect all foreign matter on the side (on the reticle glass surface side).Furthermore, it is also possible to selectively detect foreign matter on the front side as well.In the figure, la is a pattern.

Therefore, by sending the position signals of each of the XY tables, the driving position detection 3.4, and the signal of the optical sensor 22 to the γ control unit 23, the 0RT 25 and printer 26 can accurately identify the location of foreign objects on the reticle. can be detected.

After detecting a foreign object, remove any foreign objects on the reticle surface, set two wafers on the XY table 7, and set them at the exposure position. Xr can be done.

Here, the detection of the foreign matter may be performed every time the wafer 2 is exposed.

Therefore, with the projection exposure apparatus described above, foreign matter detection can be performed with the reticle 1 set at the projection exposure position, and exposure m and vc detection can be performed for each one shot seven times, so that exposure +*F]i■ It is possible to detect foreign substances that have been deposited on the skin, and the tip of the eye can be rubbed thoroughly. In addition, this device
Projection optical system 8 vc +) which is conventionally provided in l.
Since the detection optical system 14 consisting of the lens 16, 17 and the reflecting mirror 18, 19 and the optical sensor 22 can be installed, the overall configuration can be simplified and the cost can be reduced. Furthermore, by adjusting the light emitted from the reticle, it is possible to detect foreign objects on the front and back surfaces of the reticle, and it is also possible to detect cranks in the trenches.

Incidentally, as shown in FIG. 3, the support plate 28 of the reticle 1?
The support plate 28
It is also possible to introduce a reflective mirror 199r into the support plate 28 (c).
The light is then refracted on the inner surface of the V-trowel and is irradiated onto the L/Dicle surface at a minute angle. In this case, the angle bw changing mechanism 21 of the reflecting mirror 19 can be omitted. Above book f+lI&
Although we have described the above using a lens fine-image optical system, it can also be performed in the same way with a mirror reflective projection optical system using a scanning system or a step-and-repeat fog light system.

'f7j%t-'Chicle 1 (The light that hits υ from one side is the light multiplied by polarized light r=k You may do all you can to receive the light.

As described above, according to the projection exposure apparatus of the present invention, since light is irradiated onto the surface of the reticle approximately parallel to the surface of the reticle, foreign matter can be detected even when the reticle is set in the projection exposure apparatus rC and immediately before exposure. This makes it possible to accurately detect foreign objects and perform a suitable projection exposure. In addition, since it is only necessary to add a foreign object detection optical system and an optical sensor, the structure is simple and can be manufactured at low cost. Furthermore, by controlling the light irradiation, it is possible to identify harmless foreign substances and harmful foreign substances, and it is also effective in that it is possible to detect crumbs on the surface of the glass substrate of the reticle.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the projection exposure apparatus of the present invention, FIG. 2 is a partially enlarged view for explaining the operation, and FIG. 3 is a diagram similar to FIG. 2 of another embodiment. 1... Reticle, 2... Ueno, 7... XY table, G... Projection exposure optical system, 10... Mercury lamp,
12... Reduction imaging lens, 13... Shutter, 14
...Foreign object detection optical system, 22... Optical sensor, 23...
- Control unit, 27... shutter, 28... support plate. Figure 1 Figure 2 Figure 2 Figure 3

Claims (1)

[Claims] 1. A projection optical system that projects and exposes an image drawn on a glass substrate onto a wafer surface, and an exposure illumination optical system that guides a portion of the illumination light source light to the side of the glass substrate. a second illumination optical system that irradiates at least approximately parallel to the image plane of the glass substrate; and a second illumination optical system that can be installed at the image formation position of the glass substrate and detects all the diffusely reflected light from the glass substrate by the irradiation light of the second illumination optical system. A projection exposure apparatus that is equipped with a light sensor and a full-featured optical sensor. 2. The optical sensor is not a photoelectric element, and the wafer is placed on it.
(The projection exposure apparatus according to claim 1, which is attached to a part of an xy table. 3. The second illumination optical system irradiates light at a minute angle with respect to the surface of the glass substrate. The projection exposure apparatus according to item 2 of the scope of the first mound or V technique.