KR20070055722A - Wafer stage cleaning apparatus of exposure equipment for manufacturing semiconductor - Google Patents

Abstract

Disclosed is a wafer stage cleaning apparatus of an exposure facility for semiconductor manufacturing. The wafer stage cleaning apparatus of the exposure apparatus for semiconductor manufacturing of this invention is a cleaning housing provided so that relative movement with respect to a wafer stage is possible on the wafer stage with a wafer chuck; Air having at least one air sprayer formed in the cleaning housing for injecting air onto the wafer stage, a compressor for providing air injected through the air sprayer, and an air sprayer for connecting the air sprayer and the compressor Injection unit; And a plurality of particle suction holes provided in adjacent areas of the air spraying holes of the cleaning housing to suck particles suspended from the wafer stage by air, a vacuum pump for providing a vacuum to the particle suction holes, and a particle suction hole and a vacuum pump. Characterized in that it comprises a particle suction having a particle suction pipe connecting the. According to the present invention, there is no need for human direct access, and the particles of the wafer stage can be removed automatically or semi-automatically without polishing the wafer chuck, so that the surface of the wafer chuck, chemical or mechanical (Mechanical) It can prevent contamination of exposure equipment and change of state of exposure equipment due to poor polishing work.

 Semiconductor, Exposure Equipment, Particles, Cleaning Housing, Air Jet, Particle Suction

Description

Wafer Stage Cleaning Apparatus for Exposure Equipment for Semiconductor Manufacturing

1 is a partial perspective view of an exposure apparatus in which a wafer stage cleaning apparatus according to an embodiment of the present invention is installed.

FIG. 2 is a bottom view of an ultra lens block portion of the exposure apparatus of FIG. 1. FIG.

3 is a partial perspective view of the wafer stage cleaning apparatus of FIG. 1.

4 is a schematic cross-sectional view for describing a process of cleaning a wafer chuck on the wafer stage cleaning apparatus of FIG. 1.

* Explanation of symbols for main parts of the drawings

    1: wafer stage cleaning device P: particle

    3: ultralens block 5: ultralens

    7: wafer stage 10: cleaning housing

   11 wing 21 air sprayer

   23: air injector 25: compressor

   30: particle suction part 31: particle suction hole

   33: particle suction pipe 35: vacuum pump

   37 filter

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer stage cleaning apparatus for exposure equipment for semiconductor manufacturing, and more particularly, to the particle of the wafer stage automatically or semi-automatically without the need for direct human access and without polishing the wafer chuck. It relates to a wafer stage cleaning apparatus of an exposure apparatus for manufacturing a semiconductor that can be removed.

In general, a semiconductor device manufacturing process is a process of manufacturing an electronic circuit that performs a predetermined function on a wafer by forming a semiconductor layer, an insulating layer, and a conductive layer having different properties on a semiconductor wafer in combination with a stacking order and a pattern shape. It can be said. In particular, a semiconductor memory device, a semiconductor logic device, etc. are repeatedly implemented on a semiconductor wafer a plurality of chips having the same function and shape using a photo mask designed for a certain purpose, especially in the case of a semiconductor memory device A plurality of unit cells having a form are repeatedly formed in a matrix form.

In this semiconductor manufacturing process, a photo-lithography process is performed to primarily implement a pattern laid out on a mask on a wafer. To this end, a photoresist called photoresist is applied on the wafer, and light energy having a specific wavelength is exposed on the photoresist-coated wafer through a mask on which a pattern is formed. As a result, a photochemical reaction occurs due to light energy, and a pattern is formed on the photoresist by using a chemical reaction due to a difference in solubility in the exposed and non-exposed regions during the subsequent development process. The photoresist pattern thus formed serves as a mask in a subsequent etching or ion implantation process and is finally stripped by an O ₂ plasma or the like.

In such a lithography process, a semiconductor manufacturing equipment called a spinner is used, which applies a photoresist to a wafer and a photoresist exposed by a stepper to develop a pattern of the photoresist. A developing process for forming a film is performed. In other words, the spinner facility is a device capable of performing a spin coating and developing process on a semiconductor wafer by a spin method, and is generally configured as an in-line system together with an exposure facility such as a stepper. do. The spinner facility performs the main processes such as baking and developing from the photosensitive agent application through automatic transfer of wafers by a robot.

On the other hand, semiconductor exposure equipment such as steppers are particularly sensitive to particles, so that large defects may occur even by fine particles. These particles are used when the particles around the wafer stage are blown by the air conditioning wind of the exposure equipment to contaminate the upper surface of the wafer chuck. Particles attached to the handling arm loading the contaminated upper surface of the wafer stage may be contaminated by various causes such as when the particles are transferred to the wafer chuck.

In the case where particles are present on the upper surface of the wafer chuck in the semiconductor exposure process, the wafer mounted on the wafer chuck may have a slight height difference due to the particles. Defocus occurs due to the height difference, and pattern defects are locally generated on the wafer. Since such pattern defects are a major cause of yield reduction in the process, it is almost essential to clean the wafer stage to remove all particles on the wafer chuck when particles are present on the wafer stage.

Therefore, in order to remove the particles on the wafer stage, visually check whether there is any particle on the upper surface of the wafer chuck, or check the pattern formed on the wafer to confirm the existence of particles. The wafer chuck is washed through. In other words, when there are particles on the wafer stage, a person directly approaches the wafer stage inside the exposure apparatus and removes them by chemical or mechanical polishing. In the case of mechanical polishing, the wafer chuck is a method of dropping particles out of the upper surface of the wafer chuck by directly rubbing a cleaning tool, such as a smooth oil stone, onto the wafer chuck surface by hand while directly contacting the wafer chuck. Was washed.

However, in order to remove the particles on the wafer stage as described above, by visually checking the pattern formed on the wafer to check the existence of the particles, if there are particles on the upper surface of the wafer chuck, a person manually cleans the wafer chuck by hand. It is difficult to check the occurrence of particles from time to time, and there is a problem that requires excessive time due to the preliminary work for the person to directly access the wafer stage, as well as chemical or mechanical polishing ( The surface damage of the wafer chuck or the chemical or mechanical polishing work due to the polishing operation may cause contamination of the exposure equipment and change of state of the exposure equipment.

Accordingly, an object of the present invention is to solve such problems in the prior art, and it is not necessary for a human to approach directly, and it is possible to remove particles of the wafer stage automatically or semi-automatically without polishing the wafer chuck. To provide a wafer stage cleaning apparatus for exposure equipment for semiconductor manufacturing which can prevent contamination of the exposure equipment and change of state of the exposure equipment due to surface damage of the wafer chuck or poor chemical or mechanical polishing operations. .

In addition, another object of the present invention is to provide a wafer stage cleaning apparatus of an exposure apparatus for manufacturing a semiconductor which can automatically detect a position where particles exist and clean the wafer stage automatically.

The object is, according to the present invention, a cleaning housing provided to be movable relative to the wafer stage above the wafer stage having a wafer chuck; At least one air injection hole formed in the cleaning housing for injecting air onto the wafer stage, a compressor providing air injected through the air injection hole, and air connecting the air injection hole and the compressor An air injection unit having an injection pipe; And a plurality of particle suction holes provided in adjacent areas of the air injection hole of the cleaning housing to suck particles suspended from the wafer stage by the air, and a vacuum pump for providing a vacuum to the particle suction holes. And a particle suction part having a particle suction pipe connecting the particle suction hole and the vacuum pump.

Here, it is advantageous for the cleaning housing to have a wing portion extending in the radial direction at the end to suck floating particles.

In addition, the wing portion may have a structure in which the thickness becomes thinner toward the radially outer side.

In addition, the cleaning housing is preferably provided in the region adjacent to the ultra-lens block is provided on the wafer stage, the ultra-lens block through which the light to the wafer stage passes.

On the other hand, the wafer stage cleaning apparatus further comprises a control unit for controlling the movement of the wafer stage, the control unit, the wafer stage so that the air injection hole is located above the coordinate point on the wafer stage where the focusing failure has occurred You can move it.

The air injection holes may be disposed in the center of the cleaning housing, and the particle suction holes may be disposed in a circumferential direction on the outside of the air injection holes.

The particle suction pipe may be provided with a filter for removing the particles.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a partial perspective view of an exposure apparatus provided with a wafer stage cleaning apparatus according to an embodiment of the present invention, FIG. 2 is a bottom view of an ultralens block portion of the exposure apparatus of FIG. 1, and FIG. 3 is a wafer of FIG. 1. 4 is a partial perspective view of the stage cleaner, and FIG. 4 is a schematic cross-sectional view for explaining a process of cleaning the wafer chuck on the wafer stage cleaner of FIG. As shown in these figures, the wafer stage cleaning apparatus 1 according to an embodiment of the present invention, the ultra-lens (5) is provided on the wafer stage 7, the light passing toward the wafer stage (7) passes through Is installed in the adjacent area of the ultra-lens block (3) is installed.

The wafer stage cleaning apparatus 1 includes particles P which remain in the wafer chuck through the cleaning housing 10 coupled to the ultra lens block 3 and the air spray holes 21 formed in the cleaning housing 10. , particles, the wafer stage by the air injection unit 20 for injecting air toward the air and the air injected from the air injection unit 20 through the particle suction hole 31 formed in the cleaning housing 10 The particle suction part 30 which sucks in the particle P suspended from (7), and the control part (not shown) which controls the movement of the wafer stage 7 are provided. Here, the wafer stage 7 includes a wafer chuck for adsorption and fixation of the wafer, a reflection image sensor (RIS) plate and a reticle in which various marks are positioned at the edges to evaluate the performance of the lens. Various measuring devices, such as first and second fiducial plates used for the alignment of the (reticle), are provided.

The cleaning housing 10 is provided to be movable relative to the wafer stage 7 above the wafer stage 7. In the present embodiment, the cleaning housing 10 is installed in an area adjacent to the ultra lens block 3 in which the ultra lens 5 is installed so as not to affect the exposure process, and the end of the cleaning housing 10 is disposed at the wafer stage ( In 7) it is installed to be placed at a certain distance. And the wing portion 11 extending in the radial direction is provided at the end of the cleaning housing 10, this wing portion 11 is formed in a structure that becomes thinner toward the outer radial direction. Because the wing 11 is guided so that the particles floating by the injection of compressed air can flow into the particle suction hole 31 to be described later without spreading around, the wing 11 is advantageous in sucking the particles. Provide structure.

The air injection unit 20 for injecting air for removing particles on the wafer chuck is formed in the cleaning housing 10, and the air injection hole 21 for injecting air onto the wafer stage 7 and the air powder. And a compressor 25 for providing air injected through the hole 21, and an air injection pipe 23 for connecting the air injection hole 21 and the compressor 25 to each other. In this embodiment, the compressor 25 is used in the exposure equipment to maintain the environment of the wafer stage, but may be provided separately, and the air spraying hole 21 is formed at the center of the cleaning housing 10. . In such a configuration, compressed air is injected into the air spray hole 21 to the wafer stage 7 to separate particles adhering to the wafer chuck from the wafer chuck.

The particle suction part 30 includes a plurality of particle suction holes 31 provided in an adjacent region of the air injection hole 21 of the cleaning housing 10 to suck particles suspended from the wafer stage 7 by air, It is provided with a vacuum pump 35 for providing a vacuum to the particle suction hole 31, and a particle suction pipe 33 for connecting the particle suction hole 31 and the vacuum pump 35. In the present embodiment, the vacuum pump 35 is used in the exposure equipment to maintain the environment of the wafer stage, but may be provided separately, the particle suction hole 31 is circumferential to the outside of the air injection hole 21 Thus, a plurality of cleaning housings 10 are formed. The particle suction pipe 33 is provided with a filter 37 for removing particles.

On the other hand, the controller (not shown) controls the operation of the air injection unit 20 and the particle suction unit 30, including the movement of the wafer stage 7. In particular, the controller may move the wafer stage 7 such that the air injection hole 21 is positioned above the coordinate point on the wafer stage 7 on which the focusing failure has occurred. Therefore, if focusing failure occurs due to contamination, that is, particles on the wafer chuck, the controller stores the X and Y coordinates on the wafer stage 7 on which the focusing failure has occurred, and removes the particles causing the focusing defect. (7) will be moved. As a result, the wafer stage 7 is moved during cleaning, and the air injection holes 21 formed in the cleaning housing 10 are placed on the upper part of the position where the particles are present.

 With this configuration, the operation of the wafer stage cleaning apparatus according to an embodiment of the present invention will be described.

The wafer stage 7 includes an X stage and a Y stage which are movable in the X-axis and Y-axis directions, and each stage is capable of linear movement by respective drive motors. This is designed to implement a precise exposure process by adjusting the focus alongside the wafer chuck and the ultralens 5. In the wafer stage cleaning apparatus 1 according to an embodiment of the present invention, the X stage and the Y stage serve to transfer the wafer chuck for the cleaning operation. Therefore, it is possible to prevent the loss of cost and the complexity of the structure by not adding a new transfer device, and also to prevent secondary particle contamination which may be caused by the movement of the new transfer device.

As a result, when a focus failure occurs due to a particle on the wafer chuck, the control unit senses X and Y coordinates on the wafer stage 7 on which the focus failure has occurred, and the air injection hole of the cleaning housing 10 at that point. The wafer stage 7 is positioned so that the 21 is placed.

Then, the compressed air is injected into the air injection hole 21 toward the wafer stage 7, whereby the compressed air impacts the particles attached to the upper surface of the wafer chuck. The particles on the wafer chuck then separate from the wafer chuck and float above the wafer stage 7. At this time, the wing portion 11 serves as a barrier wall so that the particles floating by the injection of compressed air can flow into the particle suction hole 31 without being spread by the wing portion (11). On the other hand, by directly impacting the particles with the compressed air through the air injection hole 21 as described above it is possible to reduce the damage of the wafer chuck due to the direct friction between the conventional wafer chuck and the wafer stage cleaning device (1) and also close to the wafer chuck upper surface Particles that are difficult to separate or fine particles can be easily separated.

Next, the particles impacted by the compressed air are separated from the upper surface of the wafer chuck to float above the wafer stage 7 and are easily absorbed. Then, when the vacuum pump 35 is operated to provide vacuum to the plurality of particle suction holes 31 by the vacuum pump 35, the suspended particles are sucked into the particle suction holes 31.

Particles sucked into the particle suction hole 31 are moved along the particle suction pipe 33 and filtered by the filter 37 installed in the particle suction pipe 33.

This cleaning process can be repeated continuously and can be performed any number of times as needed.

As described above, the cleaning housing 10 is installed in the ultra lens block 3 around the ultra lens 5, and the air injection hole 21 for injecting air toward the particles remaining on the wafer chuck is cleaned. The cleaning housing 10 is further provided with a particle suction hole 31 provided in the housing 10 and sucking the particles suspended from the wafer stage 7 by the air injected from the air injection hole 21. When the focusing failure occurs in the ultra-lens 5, by providing a control unit for moving the wafer stage 7 so that the air injection hole 21 is positioned above the coordinate point on the wafer stage 7 in which the focusing failure occurs, This position can be detected automatically and the wafer stage 7 can be cleaned automatically instead of manually.

In the above-described embodiment, a single air spraying hole 21 is disposed in the center of the cleaning housing 10 and a plurality of particle suction holes 31 are disposed around the air spraying hole 21. A plurality of air injection holes 21 may be installed in the center of the cleaning housing 10, and a plurality of particle suction holes 31 may be disposed in the center of the cleaning housing 10 and outside the particle suction holes 31. A plurality of air injection holes 21 may be arranged.

As described above, the present invention is not limited to the described embodiments, and various modifications and changes can be made without departing from the spirit and scope of the present invention, which will be apparent to those skilled in the art. Therefore, such modifications or variations will have to be belong to the claims of the present invention.

As described above, according to the present invention, there is no need for a person to directly access, and the particles of the wafer stage can be removed automatically or semi-automatically without polishing the wafer chuck, so that the surface of the wafer chuck is damaged or chemically. Alternatively, the contamination of the exposure equipment and the change of state of the exposure equipment can be prevented due to a poor mechanical polishing operation.

The apparatus may further include a control unit that installs a cleaning housing around the ultra lens block around the ultra lens and moves the wafer stage such that the air injection hole is positioned above the coordinate point on the wafer stage where the focusing defect occurs when the focusing defect occurs in the ultra lens. As a result, the wafer stage may be automatically cleaned by automatically detecting a position where particles are present.

Claims (7)

A cleaning housing provided on the wafer stage having a wafer chuck so as to be movable relative to the wafer stage; At least one air injection hole formed in the cleaning housing for injecting air onto the wafer stage, a compressor providing air injected through the air injection hole, and air connecting the air injection hole and the compressor An air injection unit having an injection pipe; And A plurality of particle suction holes provided in an adjacent region of the air injection hole of the cleaning housing to suck particles suspended from the wafer stage by the air, a vacuum pump for providing a vacuum to the particle suction holes, and And a particle suction part having a particle suction pipe connecting the particle suction hole and the vacuum pump. The method of claim 1, The cleaning housing is provided with a wafer stage cleaning apparatus, characterized in that the blade portion extending in the radial direction at the end. The method of claim 2, Wafer stage cleaning apparatus, characterized in that the blade portion is thinner toward the radially outer side. The method of claim 1, The cleaning housing is provided on the wafer stage, the wafer stage cleaning apparatus, characterized in that installed in the adjacent region of the ultra-lens block is provided with an ultra-lens through which the light to the wafer stage passes. The method of claim 4, wherein Further comprising a control unit for controlling the movement of the wafer stage, And the control unit moves the wafer stage such that the air injection hole is positioned above a coordinate point on the wafer stage where focusing failure has occurred. The method of claim 1, The air injection hole is disposed in the center of the cleaning housing, the particle suction hole is a plurality of wafer stage cleaning apparatus, characterized in that disposed in the circumferential direction on the outside of the air injection hole. The method of claim 1, And a filter for removing the particles in the particle suction pipe.

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