WO2004027856A1

WO2004027856A1 - Method for supporting substrate, substrate supporting apparatus and exposure apparatus

Info

Publication number: WO2004027856A1
Application number: PCT/JP2003/008795
Authority: WO
Inventors: Hidekazu Kikuchi
Original assignee: Sendai Nikon Corporation; Nikon Corporation
Priority date: 2002-09-19
Filing date: 2003-07-10
Publication date: 2004-04-01
Also published as: JP2004111685A; AU2003298996A1; AU2003298996A8

Abstract

A substrate supporting apparatus has a supporting member (10), which supports a substrate from below at three or more points (supporting points). The supporting member comprises a pillar (11) extending in the direction of height, a crossbar (13), which horizontally extends from the end of the pillar, and a rubber ring (15) fitted on the crossbar. By vertically arranging the rubber ring (15), the outer surface of the rubber ring is of a convex shape, thereby coming into contact with the substrate at a single point, the uppermost point of the rubber ring. Consequently, no space is formed between the substrate and the rubber ring and thus, no suction-cup phenomenon occurs. Therefore, neither vibration nor positional deviation occurs when the substrate is dismounted.

Description

Description Substrate holding method, substrate holding apparatus, and exposure apparatus

The present invention relates to a method and an apparatus for holding a substrate such as a wafer and a reticle in a vacuum treatment apparatus, a semiconductor manufacturing apparatus, an exposure apparatus, and the like. Background art

As a method of holding a substrate such as a wafer reticle in a semiconductor manufacturing apparatus, a vacuum suction method using a flat table is most widely used. However, when holding a substrate in a vacuum environment, this vacuum suction method cannot be used, and a method of mechanically clamping the substrate from above or from the side has been adopted. However, this method causes problems such as generation of wear powder due to mechanical contact and friction, and damage to the substrate.

Therefore, conventionally, a method has been adopted in which a substrate is placed on an elastic member provided above a plurality of columns.

FIG. 6 is a side view of a conventional substrate holding device.

As shown in the figure, the conventional substrate holding device has a plurality of support members 200 and 200 '. The support members 200 and 200 'are composed of columns 201 and 201' and a disc-shaped rubber pad 203 provided on the top of the columns. The rubber pad 203 is made of fluororubber having a high friction coefficient of 0.2 to 0.3, and has a size (diameter) of several mm. There is a method using ceramics, aluminum, or resin instead of fluororubber, but such a material is not effective because its coefficient of friction is as small as 0.1 or less.

In the support member 200 shown in FIG. 6 (A), the column 201 is fixed to the port 205. Porto 205 is screwed from above base 3 and secured by nuts 205. By rotating Porto 205, The length of the port 205 extending upward from the base 3 changes, and the height of the column 201 can be adjusted.

The support column 201 of the support member 200 ′ shown in FIG. 6B is fixed to the pin 209, and the pin 209 is fitted into the base 3. The height of the column 201 'is fixed, but the height of the column 201' can be adjusted by inserting a shim between the base 3 and the column 201 '.

Such support members 200 are provided at a plurality of locations along the outer edge of the substrate on the holder base 3. The outer edge of the substrate W is placed on the rubber pad 203 of the support member 200. Since the rubber pad 203 has a high friction coefficient as described above, the substrate W is unlikely to be displaced even when disturbance vibration occurs. It is also effective in the vacuum.

In such a substrate holding apparatus, when high precision is required for the position of the substrate, it is necessary to reduce the amount of positional deviation that occurs when the substrate is transferred. The rubber pad 203 is attached to the upper end surface of the column 201 by bonding, and the bonding may cause the upper surface of the pad 203 to be concavely curved. When the substrate W is placed on the upper surface of the curved rubber pad 203, a space S is formed between the substrate W and the upper surface of the pad 203. Then, a sucker phenomenon occurs, and the substrate W may be adsorbed on the upper surface of the pad. In the case of the air, such adsorption force is generated because there is air around.

In this way, if the substrate is picked up by a transport robot or the like while the substrate is being attracted to the pad with a certain force, the attracting force is lost when the substrate is separated from the pad, and the reaction force generates vibration on the substrate. May cause misalignment. The amount of the positional deviation varies from several to several hundreds. If the amount of displacement is large, problems such as the inability to read the mark on the stage during the bri-alignment occur. In an exposure apparatus that requires high accuracy, it is required that the positional deviation amount during substrate handling be several tens of meters / m or less, and that the deviation amount error be stable. Disclosure of the invention

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a substrate holding device and a method for reducing the positional deviation generated during pickup and stabilizing the amount of deviation.

In order to solve the above problems, a substrate holding method according to the present invention is a method for holding a substrate such as a wafer or a reticle, wherein three or more points (support points) of the substrate are soft or non-conductive from below. It is supported by a support member having an upwardly convex support portion made of an adhesive material.

The substrate holding apparatus of the present invention is an apparatus for holding a substrate such as a wafer or a reticle, and supports at least three points (supporting points) of the substrate from below. A support member having a convex support portion is provided.

By supporting the substrate with the upwardly convex, soft, non-adhesive support portion, a space for generating a suction force is not formed between the substrate and the support portion, and the sucking phenomenon can be prevented. Therefore, no vibration or displacement occurs when the substrate is removed. Therefore, it is suitable for application to a field in which a displacement of several tens of meters is a problem, such as a brialignment in an exposure apparatus.

In the present invention, if the support portion of the support member is a rubber ring or a rubber block, the friction member has a high friction coefficient, so that it is unlikely to be displaced by disturbance vibration. Also, it can be used in air and vacuum.

In the present invention, the horizontal state of the substrate can be adjusted if the support member has a height adjustment mechanism for the support portion.

Another substrate supporting device of the present invention is a device for holding a substrate such as a wafer or a reticle, and has a supporting member for supporting three or more points (supporting points) of the substrate from below, and The member is constituted by a column extending in the height direction, a horizontal bar extending laterally from a tip of the column, and a rubber ring fitted into the horizontal bar.

By arranging the rubber ring in the vertical direction, the outer peripheral surface of the rubber ring State. As described above, since the substrate is in contact at the uppermost point of the rubber ring, no space is formed between the substrate and the rubber ring, and the sucker phenomenon does not occur. If the contact portion of the rubber ring is worn, the ring can be rotated around a horizontal bar to make contact with the substrate on a new outer peripheral surface. In addition, rubber rings are readily available, so if the rubber ring becomes worn or deteriorated and needs to be replaced, it can be easily replaced.

An exposure apparatus according to the present invention is an exposure apparatus that selectively irradiates a sensitive substrate with an energy beam to form a pattern, and includes the substrate holding device according to any one of the above.

Since the wafer / reticle can be held without displacement, the bri-alignment / transport operation can be performed with high precision. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram showing a structure of a support member of a substrate holding device according to an embodiment of the present invention, wherein FIG. 1 (A) is a side view and FIG. 1 (B) is a front view.

FIG. 2 is a plan view showing the overall structure of the substrate holding device.

FIG. 3 is a plan view showing a substrate loader provided with the substrate holding device of FIG. FIG. 4 is a side view showing a structure of a substrate holding device according to another embodiment of the present invention.

FIG. 5 is a diagram schematically illustrating a configuration of an exposure apparatus according to an embodiment of the present invention.

FIG. 6 is a side view of a conventional substrate holding device. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, description will be made with reference to the drawings.

FIG. 1 is a diagram showing a structure of a support member of a substrate holding device according to an embodiment of the present invention, where FIG. 1 (A) is a side view and FIG. 1 (B) is a front view.

FIG. 2 is a plan view showing the entire structure of the substrate holding device. As shown in FIG. 2, the substrate holding device 1 has three support members 10 arranged on the holder base 3 at the same central angle (120 °). As shown in FIG. 1, the support member 10 is composed of a column 11, small screws (horizontal bar) 13, and a rubber ring (support portion) 15. The support 11 includes a head 11 a and a port 11. The port 11 b is inserted into a screw hole 5 formed in the holder base 3 and fixed with a nut 17. A small screw 13 is screwed into the head 11a from the side. A groove 13 b having a concave cross section is formed along the outer peripheral surface of the head portion 13 a of the small screw 13. A rubber ring 15 is fitted in the concave groove 13b. The rubber ring 15 is made of a soft, non-adhesive fluoro rubber. Alternatively, it may be made of nitrile rubber or silicone rubber. As can be seen from FIG. 1, the uppermost part of the outer peripheral surface of the rubber ring 15 is in an upwardly convex state, and the uppermost part is located higher than the small screw 13.

As shown in FIG. 2, the support member 10 is disposed along a substantially outer edge of the substrate W at a center angle Θ (120 °) equal to that on the holder base 3. The rubber ring 15 side of the member is located outside.

The substrate W is placed on the rubber ring 15 of each support member 10. Since the rubber ring 15 is arranged in the vertical direction, the outer peripheral surface is convex upward, so that the lower surface of the substrate W and the uppermost portion of the outer convex surface are almost in contact with each other. Since the coefficient of friction between the rubber ring 15 and the silicon or glass substrate is as high as 0.1 to 0.3, even if the rubber ring 15 and the substrate W make contact at points, the displacement of the substrate W It does not easily occur and is kept stable. Also, since the two are almost in contact at a point, no space is formed between them, and the sucker phenomenon that occurs when the contact surface becomes concave does not occur. Therefore, no force other than its own weight acts on the substrate W, and when the substrate W is picked up, no displacement occurs due to the reaction force to the attraction force. In addition, the displacement error can be stabilized within a narrow range (about several meters).

In addition, the height of the support can be adjusted by rotating the support 11.

If the contact area of the rubber ring 15 is worn or damaged, Turn the ring around the machine screw 13 so that the new face of 15 is at the top. If the rubber ring 15 has deteriorated, it can be easily replaced by removing the ring from the small screw 13. Since the rubber ring 15 is easily available, maintenance is easy.

Further, instead of the rubber ring 15, a rubber block having an upwardly convex surface may be attached to the upper end surface of the column.

FIG. 3 is a plan view showing a substrate loader provided with the substrate holding device of FIG. The substrate loader (vacuum port pot) 30 is disposed in the vacuum port pot chamber 31. The chamber 31 is provided with a turbo pump 33 to evacuate the chamber. The vacuum robot chamber 31 has a hexagonal planar shape, and each side faces various substrate transport destinations. One of the side surfaces communicates with the wafer chamber 121 of the exposure apparatus 100 via a gate valve 35. A stage 13 1 is provided in the wafer chamber 12 1.

The board opening 30 is connected to the base 37 so as to articulate to the base 37 and to the first arm 39 and the first arm 39 fixed to be movable in the Z direction. And a second arm 41, and an end effector 43 connected to the second arm 41 so as to rotate. The end effector 43 rotates in the XY plane and moves in the Z direction.

Another side of the vacuum port pot chamber 31 communicates with a bri-alignment chamber 45. A briar alignment holder 47 is provided in the bri-alignment chamber 45. On the bri-alignment holder 47, the substrate holding device 1 shown in FIG. 1 is provided. The other two sides of the vacuum robot chamber 31 communicate with mouth lock chambers 53, 55 via gate valves 49, 51, respectively. Load lock holders 57, 59 are installed in each of the load lock chambers 53, 55. Gate valves 61, 63 are provided at the entrances of the respective drop chambers 53, 55. The substrate holding device 1 is also provided on the mouth lock holders 57 and 59 in each load box. The remaining two sides of the vacuum robot chamber 31 are sealed with a sealing plate 65.

Atmospheric loaders (atmospheric robots) 67 are installed outside the load lock chambers 53, 55. The atmospheric loader 67 has a base 71 fixed on a base 69, a first arm 73 fixed to the base 71 and movable movably in the Z direction, and a first arm 73 fixed to the first arm 73. The second arm 75 is connected to the second arm 75 and the end effector 77 is connected to the second arm 75 so as to articulate. The end effector 7 can rotate in the XY plane and move in the Z direction.

On the frame 69, a cassette section 79 and a bri-alignment section 81 are provided.

The operation of the substrate loader 30 will be described.

First, the atmospheric loader 67 takes out the wafer from the cassette section 79 on the gantry 69 and transfers it to the bri-alignment section 81. A briar alignment will be conducted at the same department. Thereafter, the gate valve 63 at the entrance of the load lock chamber 55 is opened, and the wafer is transferred to the door lock holder 59 in the chamber by the atmospheric loader 67. Then, the gate valve 63 at the inlet is closed, and the first lock chamber 55 is evacuated.

Thereafter, the gate valve 51 on the vacuum robot chamber side of the mouth lock chamber 55 is opened, the wafer is taken out from the mouth lock chamber 55 by the vacuum loader 30, and the brialignment chamber of the blind alignment chamber 45 is opened. Conveyed to da47. Then, higher precision briar alignment is performed in the same chamber 45. In the EB exposure system, the mechanism is not installed in the stage chamber but is installed on the vacuum loader side in order to prevent the influence of the magnetic field generated from the bri-alignment mechanism. Due to such a configuration, high-precision positioning is required when a wafer that has been subjected to high-precision brialignment is transferred to a stage in the exposure apparatus main body.

Therefore, the substrate holding device shown in FIGS. Device 1 is provided. For this reason, when the wafer is picked up from the pre-alignment holder 47 by the vacuum port header 30, the misalignment hardly occurs, and the wafer is transferred from the bri-alignment holder 47 to the holder on the wafer stage 13 1 with high precision. be able to. Further, at the time of the bri-alignment, it is possible to prevent the substrate from being displaced due to vibration generated by driving the stage in the exposure apparatus main body or vibration transmitted from the floor.

FIG. 4 is a side view showing a structure of a substrate holding device according to another embodiment of the present invention.

The support member 20 of the substrate holding device of this example includes a support 21, small screws 23, and rubber rings 25. The support 21 is erected on the holder base 3 by screws 27 screwed from holes 5 on the lower surface of the holder base 3. A small screw 23 is screwed into the upper part of the column 21. A groove having a concave cross section is formed along the outer peripheral surface of the head portion of the small screw 23. A rubber ring 25 is fitted in the concave groove.

In the support member 20 of the substrate holding device, since the height of the column 21 is constant, the height of the substrate holding surface can be constant. In addition, the position of the uppermost portion of the outer peripheral surface of the rubber ring 25 becomes constant, and it is effective to apply to a reticle having a limited contact portion. In other words, when the support 11 is rotated when adjusting the height of the support member 10 in FIG. 1, the rubber ring 15 also rotates around the support 11 so that the ring 15 and the substrate W The contact position changes. On the other hand, when adjusting the height of the support member 21 of this embodiment, a shim may be inserted between the column 21 and the holder base 3 so that the circumferential position of the rubber ring 25 is the initial position. does not change.

FIG. 5 is a diagram for schematically explaining the configuration of the exposure apparatus according to the embodiment of the present invention.

An optical lens barrel 101 is disposed above the electron beam exposure apparatus 100. A vacuum pump (not shown) is installed in the optical column 101, and the inside of the optical column 101 is evacuated.

An electron gun 103 is arranged at the top of the optical barrel 101, and is directed downward. Emits an electron beam. Below the electron gun 103, an illumination optical system 104 including a condenser lens 104a, an electron beam deflector 104b, and the like are arranged in this order. A reticle R is disposed below the lens barrel 104.

The electron beam emitted from the electron gun 103 is converged by the condenser lens 104a. Subsequently, the light is sequentially scanned (scanned) in the horizontal direction in the figure by the deflector 104b, and illumination of each small area (subfield) of the reticle R within the field of view of the optical system is performed. Although the condenser lens 104a has one stage in the figure, the actual illumination optical system is provided with several stages of lenses, a beam shaping aperture, a blanking aperture, and the like.

Reticle R is supported by holder 110 of reticle stage 111. The reticle stage 1 1 1 is mounted on a surface plate 1 16.

The reticle stage 111 is connected to a drive device 112 shown on the left side of the figure. Actually, the driving device (linear motor) 112 is incorporated in the stage 111. The drive device 112 is connected to the control device 115 via a driver 114. Further, a laser interferometer 113 is set on the side of the reticle stage 111 (to the right in the figure). The laser interferometer 113 is also connected to the control device 115. Accurate positional information of the reticle stage 111 measured by the laser interferometer 113 is input to the controller 115. A command is sent from the control unit 115 to the driver 114 so that the position of the reticle stage 111 is set as the target position, and the drive unit 112 is driven. As a result, the position of the reticle stage 111 can be accurately feedback-controlled in real time.

A wafer chamber (vacuum chamber) 121 is disposed below the platen 116. A vacuum pump (not shown) is connected to the side (right side in the figure) of the wafer chamber 122, and the inside of the wafer chamber 121 is evacuated. A projection optical system 124 including a capacitor lens (projection lens) 124 a and a deflector 124 b is arranged in the wafer chamber 122 (actually in the optical barrel in the chamber). ing. The lower part of the wafer champer 1 2 1 (Substrate) W is arranged.

The electron beam passing through reticle R is converged by condenser lens 124a. The electron beam passing through the condenser lens 124a is deflected by the deflector 124b to form an image of the reticle R at a predetermined position on the wafer W. In the figure, the condenser lens 124a has one stage, but in practice, the projection optical system is provided with a plurality of stages of lenses and a lens coil for aberration correction.

After the completion of the bri-alignment, the wafer W is transferred onto the stage 13 1 by the vacuum loader 30 in the vacuum port pot chamber 31, and is supported on the holder 1 30 on the wafer stage 13 1. It is supported on 10 (see Fig. 1). The wafer stage 13 1 is mounted on the platen 13.

The driving device 13 2 shown on the left side of the figure is connected to the wafer stage 13 1. Note that the driving device 13 2 is actually incorporated in the stage 13 1. The drive unit 132 is connected to the control unit 115 via a driver 134. A laser interferometer 13 3 is installed on the side of the wafer stage 13 1 (to the right in the figure). The laser interferometer 133 is also connected to the controller 115. The accurate position information of the wafer stage 13 1 measured by the laser interferometer 13 3 is input to the controller 1 15. In order to target the position of the wafer stage 131, a command is sent from the control device 115 to the driver 134, and the drive device 132 is driven. As a result, the position of the wafer stage 13 1 can be feedback-controlled accurately in real time. The invention's effect

As is clear from the above description, according to the present invention, since the substrate is held on the support member at almost points, no displacement occurs during the pickup, and the displacement can be stabilized. This makes it possible to provide an exposure apparatus that can stably hold a substrate with high accuracy.

Claims

The scope of the claims

1. A method for holding a substrate such as a wafer or a reticle,

A substrate holding method, wherein three or more points (support points) of the substrate are supported from below by a support member having an upwardly convex support portion made of a soft or non-adhesive material.

2. A device for holding a substrate such as a wafer or a reticle,

A substrate holding device, comprising: a support member having an upwardly convex support portion made of a soft and non-adhesive material, which supports three or more points (support points) of the substrate from below.

3. The substrate holding device according to claim 2, wherein the support portion of the support member is a rubber ring or a rubber block.

4. The substrate holding device according to claim 2, wherein the support member includes a height adjustment mechanism of the support portion.

5. An apparatus for holding a substrate such as a wafer or a reticle,

A support member for supporting three or more points (support points) of the substrate from below; the support member includes a column extending in a height direction; a horizontal bar extending laterally from a tip of the column; A substrate holding device comprising a rubber ring fitted to the horizontal bar.

6. An exposure apparatus for selectively irradiating an energy beam onto a sensitive substrate to form a pattern,

A substrate holding device according to any one of claims 2 to 5,