JP2002373855A - Aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a time required for purging with inert gas in a space (optical path space), such as a space between a projection optical system and a substrate, through which an exposure light passes. SOLUTION: A same plane plate 7 is almost the same as or a little bit lower than a wafer W in height, and is attached for forming a convex step 8 on the surface of a wafer stage WST on the external periphery of the wafer W on the wafer stage WST, thereby suppressing a rapid decrease in a gap formed between an opening of a shielding member 11 and the surface of the wafer stage at the time of arranging the wafer stage WST in a purge space and a rapid decrease in an opening area of the opening 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus used for manufacturing, for example, a semiconductor device, an imaging device, a liquid crystal display device, a thin film magnetic head, and other microdevices. The present invention relates to an exposure apparatus that suppresses a decrease in the intensity of exposure light and the generation of ozone in an exposure apparatus that performs exposure.

[0002]

2. Description of the Related Art In a photolithography process for manufacturing a semiconductor device or the like, an exposure apparatus for exposing a pattern image of a photo reticle (including a reticle) onto a photosensitive substrate via a projection optical system is used. In recent years, semiconductor integrated circuits have been developed in the direction of miniaturization, and in photolithography processes, the wavelength of photolithography light sources has been reduced.

However, vacuum ultraviolet rays, especially 250 n
m, for example, a KrF excimer laser (wavelength: 248 nm), an ArF excimer laser (wavelength: 19 nm).
3 nm), F ₂ laser (wavelength 157 nm), or YA
When using light such as a harmonic such as a G laser as exposure light, there has been a problem that the intensity of the light is reduced due to absorption by oxygen and the like.

Therefore, conventionally, in an exposure apparatus having a light source such as an F ₂ excimer laser, only the optical path portion is shielded, and a gas containing no oxygen such as nitrogen is replaced with a gas containing no oxygen to transmit light. The decline in the rate was avoided.

[0005]

However, shielding of only the optical path portion is performed by moving parts such as a wafer stage and a reticle stage as in an exposure apparatus of a so-called step-and-repeat (repeated batch exposure for each step) system. However, it is difficult for an apparatus existing in the optical path, and it is inevitable that exposure light is partially exposed to air.

Further, as shown in FIG. 11, the projection optical system 1
Also in an exposure apparatus capable of performing exposure in a required inert gas atmosphere formed by supplying an inert gas to a space between 0 and the wafer W, an inert gas is supplied from around the exposure region, When the shielding member 11 for separating from the surrounding atmosphere is attached to the periphery, it takes about several seconds for the oxygen concentration in the enclosed space to decrease after the wafer W actually enters the exposure region, This has led to a decrease in throughput.

[0007] A similar problem exists when an inert gas is supplied to the periphery of the reticle. In the reticle, it takes several seconds to reduce the oxygen concentration in the space surrounded by the shielding member. , Resulting in a decrease in throughput.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an exposure apparatus that performs exposure using short-wavelength light. It is to provide a device.

[0009]

In order to solve the above-mentioned problems and achieve the object, an exposure apparatus of the present invention is an exposure apparatus for transferring a projected image of a mask pattern onto a substrate by exposure light. A shielding member is provided so as to surround the periphery of the optical member arranged in the optical path of the exposure light, and an inert gas is supplied to a space around the optical member defined by the shielding member, and the exposure light in the shielding member is An opening is provided in a portion passing therethrough, and at least one of the substrate and the mask is held so as to be able to be inserted or retracted to a position in the optical path of the exposure light and opposed to the opening, and a peripheral portion of the substrate and the mask Was held so that the height was substantially the same as the height of the member.

[0010]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. [First Embodiment] FIG. 1 shows an exposure apparatus according to a first embodiment of the present invention, showing a projection optical system, a periphery of a wafer, and a controller therefor. FIG. FIG. 2B is a diagram showing the projection optical system and the periphery of the wafer, and FIG.
FIG. 2A is a view of the state of the purge seen from above the purge space, and FIG. 2C is a view corresponding to FIG. 2B and showing a modified example thereof.

The exposure apparatus shown is, for example, an F ₂ (not shown).
A light source that emits short-wavelength laser light such as an excimer laser is provided, and illumination light is emitted from the light source. The illumination light uniformly illuminates the reticle via an appropriate illumination optical member, and the light transmitted through the reticle passes through a variety of optical members constituting the projection optical system 10 to the wafer W mounted on the wafer stage WST. Reach the surface and image the pattern on the reticle.

The wafer W is mounted on a wafer stage WST that can move in a three-dimensional direction (XYZ directions) and is moved in a stepping manner.
A reticle pattern is sequentially projected and exposed thereon. Also,
Even when applied to a scanning exposure apparatus, the configuration is almost the same.

At the time of exposure, an inert gas, for example, nitrogen gas, whose temperature has been externally adjusted, faces the wafer W at the front end (lower end) of the projection optical system 10 from the air supply passage Vi1 via the air supply valve Vi. Is supplied between the optical member provided and the wafer W (hereinafter, purge space).

Then, the inert gas supplied to the purge space is exhausted to the outside from the exhaust valve Vo via the exhaust passage Vo1.

Further, a shielding member 11 for defining the purge space and shielding the purge space from the outside atmosphere is provided so as to surround the optical member at the tip of the projection optical system 10. The shielding member 11 is hermetically attached to the projection optical system 10 and has an opening 12 with the wafer W side opened.
A part of the member is formed of the transparent member 13 so that the alignment light passes therethrough.

Further, the amount of exhaust from the exhaust valve Vo is set to be smaller than the gas supply amount because the pressure in the purge space needs to be positive. Therefore, a part of the supplied nitrogen gas is collected in the exhaust passage Vo1 and exhausted to the outside of the purge space via the exhaust valve Vo.

The inert gas leaked out of the purge space through the space between the optical member provided at the distal end of the lens barrel of the projection optical system 10 and the wafer W together with the surrounding atmosphere supplied from the air supply port 1. Air is exhausted from the exhaust port 2.

Each of the valves Vi and Vo is controlled by an environment controller 3
The wafer stage WST is controlled by the stage controller 4
Is controlled by The controllers 3 and 4 are controlled by a main controller 5 together with various controllers (not shown) so as to be synchronized with wafer exchange, alignment, and exposure timing, and a display 6 displays the control state and the like. Is done.

At the time of wafer replacement, the oxygen concentration in the purge space becomes considerably high due to the influence of the surrounding atmosphere. However, the wafer stage W on which the wafer W is mounted in the oxygen excess state
When ST is disposed in the purge space, it takes several seconds until the oxygen concentration in the purge space decreases, which causes a decrease in throughput.

Therefore, in the present embodiment, the height (thickness) substantially equal to or slightly lower than the wafer W around the outer edge of the wafer W on the wafer stage WST, and the convex step 8 is formed on the surface of the wafer stage WST. Is formed between the opening 12 of the shielding member 11 and the wafer stage surface (wafer surface) when the wafer stage WST (wafer W) is disposed in the purge space. The gap and the opening area of the opening 12 are prevented from sharply decreasing.

As shown in FIGS. 2A and 2B, a step is formed so as to surround the wafer W, so that the opening area can be prevented from sharply decreasing. The replacement time can be reduced.

It is not necessary to provide the step of the same surface plate 7 on the entire outer edge of the wafer W. If the loading position of the wafer stage WST is set in advance, as shown in FIG. It may be formed only in the path for inputting WST. In this case, the number of processing portions of the same plate can be reduced.

When the step 8 of the same surface plate 7 is a single step, it depends on the distance from the opening 12 of the shielding member 11 surrounding the purge space to the wafer W. While the effect of shortening the replacement time is not so much obtained, when the step 8 is disposed in the purge space and the opening area is minimized, the pressure in the purge space rapidly increases. With this pressure change, the surrounding atmosphere is slightly rolled up in the purge space, and the oxygen concentration in the purge space increases. In addition, the exhaust efficiency becomes worse with a decrease in the opening area, and the replacement time with the inert gas in the purge space becomes longer. Therefore, as shown in FIG. 3, a plurality of steps 8 are formed so as to gradually decrease toward the outer edge of the same surface plate 7, and the pressure in the purge space is gradually increased to suppress rapid deterioration in exhaust efficiency. Thus, the amount of the surrounding atmosphere involved is reduced, and the time for replacement with the inert gas in the purge space is reduced.

As shown in FIG. 4, the step 18 shown in FIG.
By making the inclined surface 28 smoothly outwardly inclined, the pressure change can be made gentler, the increase in the oxygen concentration in the purge space can be suppressed, and the replacement time can be shortened. [Second Embodiment] FIG. 5A shows an exposure apparatus according to a second embodiment of the present invention, showing a projection optical system and the periphery of a wafer, and FIG. FIG. 5 (c) and FIG. 5 (d) are views of the state of purging as viewed from above the purge space.
FIG. 7 is a diagram corresponding to FIG. 5B and showing a modification thereof.

In the first embodiment, an example is described in which the same surface plate 7 having the convex step 8 formed so as to surround the outer edge of the wafer W is mounted on the wafer stage WST. A plurality of through holes 38 are formed in the same surface plate 17 to gradually change the area.

As shown in FIG. 5, a small flange portion 17a having substantially the same height (thickness) as the wafer W or a plate thickness slightly lower than the wafer W is extended on the side of the face plate 17, and the flange portion 17a is provided. A through hole 38 that penetrates the same face plate 17 in the thickness direction is formed in 17a so that the purge space can communicate with the surrounding atmosphere. The through holes 38 are formed so as to increase toward the outside of the face plate 17 and decrease toward the center. The diameter of the through hole 38 is set to 1 m so that the surrounding atmosphere does not easily flow.
m or less is preferable.

According to this configuration, when the same plate 17 is disposed in the purge space, the pressure in the purge space is gradually increased to suppress a rapid decrease in the exhaust efficiency, thereby reducing the amount of the surrounding atmosphere involved. The time required for replacement with an inert gas in the purge space is reduced.

However, if the number of through holes is too small, a desired pumping speed cannot be obtained. Therefore, it is necessary to increase the diameter of the holes as the number of holes decreases. The diameter of the hole needs to be suppressed to several mm at the maximum. In FIG. 5A, the diameter of the hole is formed uniformly. However, the same effect can be obtained by reducing the number of holes as the wafer W approaches the wafer W without reducing the number as in FIG. 5B. .

As shown in FIG. 5C, similarly to the first embodiment, if the introduction path of the wafer W is determined in advance, a hole is not formed in the entire outer edge of the same surface plate 17 but is partially formed. By forming, it is possible to obtain the same effect as in the first embodiment.

In the second embodiment, the method of shortening the replacement time by providing a circular hole in the same surface plate 17 has been described. However, the present invention is not limited to the circular hole, and may be an ellipse, a square, or a polygon. It is possible to obtain the effect. In addition, the holes are regularly arranged such that the diameters of the holes are fixed or are reduced toward the wafer W. However, the positions of the holes are not regular,
Further, even when the sizes are partially different, the opening area under the purge space is gradually changed when the wafer stage WST on which the wafer W is mounted is positioned under the purge space. This makes it possible to suppress a rapid change in the pressure inside the purge space while shortening the replacement time, so that the time for replacement with the inert gas in the purge space can be shortened. Further, as a method for gently changing the opening area, a plurality of grooves 48 may be provided on the outer edge of the wafer W on the same surface plate 27 along the moving direction of the stage as shown in FIG.

FIG. 6A is a view showing the projection optical system and the periphery of the wafer, and FIG. 6B is a view showing the state of the purge shown in FIG. (C) is FIG.
It is a figure corresponding to (b) and showing the modification.

In the same figure, in order to gradually change the pressure in the purge space, the width of the groove 48 is made narrower nearer to the wafer W, and is made shallower closer to the wafer W. The effect can be obtained. FIG.
As shown in FIG. 6C, even if the groove is not provided on the entire outer edge of the wafer W as shown in FIG. 6B, as in the first and second embodiments, if the introduction path of the wafer W is predetermined, as shown in FIG. A similar effect can be obtained by partially providing the groove 48 in the groove. [Third Embodiment] In the third embodiment, the first and second
The replacement time is further reduced by adding the following configurations (i) and (ii) in addition to the configuration of the embodiment.

(I) First, as shown in FIG.
The outlets of the nozzles Vi1 and Vi2 for injecting the inert gas from the air supply passage into the purge space are arranged so as to face each other toward the purge space. The height up to the wafer W is increased. This is for improving the exhaust efficiency of the purge space from the downstream side, which is not easily affected by the flow of the surrounding atmosphere.

(Ii) Secondly, the nozzles Vi1 and Vi2 are arranged to face each other, and the amount of gas supplied from the nozzle Vi2 located upstream along the flow of the surrounding atmosphere is made larger than that of the nozzle Vi1 located downstream. Each flow control valve Vi is set, and the inert gas is supplied only to the upper part P of the purge space from the nozzle Vi1 existing downstream of the surrounding atmosphere. Further, since the gas supplied into the purge space tends to flow in the same direction as the flow of the surrounding atmosphere, the upstream nozzle Vi
2 is set to be larger than the supply amount of the nozzle Vi1. Further, when the gas is supplied from one direction on the upstream side, the replacement time of the downstream side P in the upper part of the purge space tends to be delayed, but the replacement time of the upper part of the purge space can be reduced by supplying the gas from the nozzle Vi1. .

Further, in this purge system, as shown in FIG. 7B, even if contamination occurs from the surface of the wafer W, a downward flow can be generated on the downstream side in the purge space. It is possible to suppress the rise.

As described above, the replacement time can be further reduced by using the same surface plate having an inclined surface and the above-mentioned configurations (i) and (ii) together.

In the present embodiment, the same surface plate having an inclined surface is used. However, the same effect can be obtained by using the same surface plate having another shape described in the first and second embodiments. [Fourth Embodiment] The configuration of the first to third embodiments is
As shown in FIG. 8, the present invention may be applied to reticle stage RST.

FIG. 8 shows an exposure apparatus according to a fourth embodiment of the present invention, showing a projection optical system, the periphery of a wafer, and its controller.

In the figure, shielding members 52 and 53 are also provided on the reticle stage RST side, and openings 57 and 58 are provided in portions through which illumination light passes, and nitrogen gas whose temperature has been adjusted from each opening 57 and 58 is supplied to the reticle. Spray towards R.

The shielding member 52 is attached so as to cover the optical member 56 for illuminating the illumination light of the illumination optical system 51, and has a closed structure except for the opening near the reticle R so that the supplied nitrogen gas does not leak. Similarly, the shielding member 53 is used for the projection optical system 6.
Is mounted on the projection optical system 10 so as to cover the optical member 16 to which the exposure light is incident, and has a closed structure except for the opening near the reticle R so that the supplied nitrogen gas does not leak.

The nitrogen gas is regulated by the valve Vir, and supplied into the respective purge spaces from the air supply passages Vir1 and Vir2, and the supplied nitrogen gas is recovered from the exhaust passages Vor1 and Vor2 via the valve Vor.

A flat plate around the outer edge of the reticle R on the reticle stage RST, which is substantially the same height (thickness) or slightly lower than the reticle R, and forms a convex step 68 on the reticle stage RST surface. 67 and the gap formed between the opening 57 of the shielding member 52 and the wafer stage surface (wafer surface) and the opening area of the opening 12 when the reticle stage RST (Rectil R) is arranged in the purge space. Suppress sharp decline.

The reticle stage RST is controlled by the stage controller 4 of FIG. 1 so as to synchronize with the wafer stage WST, and each valve is controlled by the environment controller 3.
The controllers 3 and 4 are controlled by the main controller 5 in synchronization with various operations.

The other configuration is the same as that of the first embodiment, and the description is omitted.

The above-described embodiment is an example of a means for realizing the present invention, and the present invention can be applied to a modification or a modification of the above-described embodiment without departing from the gist thereof. .

The exposure apparatus according to the present embodiment includes a shielding member 11 of the projection optical system 10 and a shielding member 5 of the illumination optical system 51.
2 and 53 may be provided with at least one. In this case, the same plane plate of the wafer W and the same plane plate of the reticle R are provided for the projection optical system or the illumination optical system provided with the shielding member. Can be [Manufacturing Process] Next, a manufacturing process of a semiconductor device using the above exposure apparatus will be described.

FIG. 9 shows the flow of the whole semiconductor device manufacturing process. In step 1 (circuit design), the circuit of the semiconductor device is designed. In step 2 (mask fabrication), a mask is fabricated based on the designed circuit pattern. On the other hand, in step 3 (wafer manufacturing), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is referred to as a preprocess, and an actual circuit is formed on the wafer by lithography using the above-described mask and wafer. The next step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer produced in step 4, and assembly such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). Process. Step 6 (inspection)
Then, inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, the semiconductor device is completed and shipped.
7) Yes.

FIG. 10 shows a detailed flow of the wafer process. Step 11 (oxidation) oxidizes the wafer's surface. Step 12 (CVD) forms an insulating film on the wafer surface. Step 13 (electrode formation) forms electrodes on the wafer by vapor deposition. Step 14 (ion implantation) implants ions into the wafer. In step 15 (resist processing), a photosensitive agent is applied to the wafer. Step 16
In (exposure), the circuit pattern is transferred to the wafer by the above-described exposure apparatus. Step 17 (development) develops the exposed wafer. Step 18 (etching) removes portions other than the developed resist image. Step 19 (resist stripping) removes unnecessary resist after etching. By repeating these steps, multiple circuit patterns are formed on the wafer.

[0049]

As described above, according to the present invention,
In an exposure apparatus that performs exposure using short-wavelength light, the time required for replacement with an inert gas in the purge space can be reduced, and the throughput can be increased.

[Brief description of the drawings]

FIG. 1 is a view showing an exposure apparatus according to a first embodiment of the present invention, showing a projection optical system, a periphery of a wafer, and a controller thereof.

2A is a diagram showing the projection optical system of FIG. 1 and the periphery of the wafer, FIG. 2B is a diagram showing the state of purging in FIG. It is a figure corresponding to (b) and showing the modification.

FIG. 3 is a modification of the first embodiment, and is a diagram showing the projection optical system of FIG. 1 and a periphery of a wafer.

FIG. 4 is a modification of the first embodiment, and is a diagram showing the projection optical system of FIG. 1 and the periphery of a wafer.

FIG. 5A is an exposure apparatus according to a second embodiment of the present invention, showing a projection optical system and a periphery of a wafer;
(B) is a view of the state of the purge in (a) as viewed from above the purge space, and (c) and (d) correspond to (b) and show a modification thereof.

6A is a diagram showing the projection optical system and the periphery of the wafer, FIG. 6B is a diagram showing the state of the purge in FIG. 6A viewed from above the purge space, and FIG. FIG. 14 is a diagram corresponding to FIG.

FIGS. 7A and 7B show an exposure apparatus according to a third embodiment of the present invention, showing a projection optical system and a periphery of a wafer.

FIG. 8 is a view showing an exposure apparatus according to a fourth embodiment of the present invention, showing a projection optical system, a periphery of a wafer, and a controller therefor.

FIG. 9 is a flowchart showing an overall semiconductor device manufacturing process.

FIG. 10 is a flowchart showing details of the wafer process of FIG. 6;

FIG. 11 is a view of a conventional exposure apparatus, showing the vicinity of a wafer from a projection optical system.

Claims (20)

[Claims] 1. An exposure apparatus for transferring a projection image of a mask pattern onto a substrate by exposure light, wherein a shielding member is provided so as to surround a periphery of an optical member disposed on an optical path of the exposure light, and the shielding member is provided by the shielding member. An inert gas is supplied to a space around the defined optical member, and an opening is provided in a portion of the shielding member through which the exposure light passes, and a position in the optical path of the exposure light that faces the opening. An exposure apparatus for holding at least one of the substrate and the mask so that the substrate and the mask can be inserted and retracted, and holding the substrate and the mask such that the height of a peripheral portion thereof is substantially the same as the height of the member. 2. The image forming apparatus according to claim 1, further comprising a projection optical system that forms an optical path of the exposure light on which the mask pattern is projected, wherein the shielding member supplies an inert gas to a portion where the exposure light is emitted from the projection optical system to the substrate. The exposure apparatus according to claim 1, wherein a space is formed. 3. A projection optical system for forming an optical path of exposure light on which the mask pattern is projected, wherein the shielding member forms a space for supplying an inert gas to a portion where the exposure light enters the projection optical system. 3. The method according to claim 1, wherein
3. The exposure apparatus according to claim 1. 4. An illumination optical system which is provided in front of the projection optical system and forms an optical path of illumination light for illuminating a mask pattern and generating a projection image, wherein the shielding member is held by the illumination optical system. The exposure apparatus according to claim 2, wherein a space for supplying an inert gas is formed in a portion of the illumination light emitted to the mask. 5. The shielding member has a supply unit that supplies an inert gas to the space and a discharge unit that discharges the inert gas supplied from the supply unit. The exposure apparatus according to claim 1. 6. The substrate according to claim 1, wherein the substrate or the mask is held by a holding member having a convex step formed around the substrate or the mask. Exposure equipment. 7. An exposure apparatus according to claim 6, wherein said step is at least one step. 8. The method according to claim 1, wherein an outer portion of the step is formed in a plurality of steps such that a portion closer to the substrate or the mask becomes shallower in a direction in which the substrate or the mask is inserted and retracted. Item 8. An exposure apparatus according to Item 7. 9. The method according to claim 8, wherein an outer portion of the step is formed as a smooth inclined surface such that a portion closer to the substrate or the mask is shallower at least along a direction in which the substrate or the mask is inserted and retracted. The exposure apparatus according to claim 7, 10. The exposure apparatus according to claim 7, wherein the step is formed only in a path for loading and retreating the substrate or the mask. 11. A flange portion having a height substantially equal to that of the substrate or the mask and extending therefrom is provided at an outer portion of the step, and at least one through hole is formed in the flange portion. 8. The method according to claim 7, wherein
3. The exposure apparatus according to claim 1. 12. The exposure apparatus according to claim 11, wherein the opening communicates with the outside of the space through the through hole. 13. The exposure apparatus according to claim 11, wherein the number of the through holes is smaller as being closer to the substrate or the mask. 14. The apparatus according to claim 1, wherein the size of the through hole is smaller as it is closer to the substrate or the mask.
An exposure apparatus according to any one of claims 1 to 13. 15. The exposure apparatus according to claim 11, wherein the through-hole is formed only at least in a path for loading or retreating the substrate or the mask. 16. A smooth groove is formed in an outer portion of the step so as to be shallower in a portion closer to the substrate or the mask along a direction in which the substrate or the mask is inserted and retracted. An exposure apparatus according to claim 7. 17. The discharge amount from the discharge unit is set to be equal to or less than the supply amount from the supply unit so that the gas pressure in the space becomes positive pressure outside the space. The exposure apparatus according to any one of claims 1 to 16. 18. The exposure apparatus according to claim 1, further comprising an exhaust unit for exhausting an inert gas leaking from the space together with a surrounding atmosphere outside the space. apparatus. 19. The exposure apparatus according to claim 1, wherein the supplied inert gas is a temperature-controlled nitrogen gas or a helium gas. 20. A step of installing a manufacturing apparatus group for various processes including the exposure apparatus according to claim 1 in a semiconductor manufacturing factory, and performing a plurality of processes using the manufacturing apparatus group. A method of manufacturing a semiconductor device.