JP2001196290A - Electrostatic chuck, stage, board processor, and charged particle beam exposer, and device manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic chuck which can exchange a wafer quickly and can enhance the throughput, a charged particle beam exposer, and others. SOLUTION: A gas introduction valve 19 in an air supply system and a gas exhaust valve 35 in an exhaust system are annexed to a stage 7. At exposure, the gas exhaust valve 35 is closed and the interior of the gas exhaust valve 37 is made vacuum in advance with a exhaust pump 41. Then, when the exposure is finished, the gas exhaust valve 35 is opened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a function of adsorbing and fixing a substrate to be processed (hereinafter sometimes abbreviated as a wafer) such as a Si wafer and releasing heat from the wafer to a chuck via a heat transfer gas. The present invention relates to an electrostatic chuck, a charged particle beam exposure apparatus having such an electrostatic chuck, and the like. In particular, the present invention relates to an electrostatic chuck, a charged particle beam exposure apparatus, and the like that can quickly exchange wafers by rapidly exhausting a heat transfer gas and increase throughput.

[0002]

2. Description of the Related Art An electrostatic chuck is used for fixing a wafer in a vacuum chamber evacuated and evacuated (such as in a charged particle beam exposure apparatus). By the way, in an exposure step of forming a pattern on a wafer, an energy beam is irradiated on a processing surface of the wafer, the temperature of the wafer rises, and the wafer thermally expands. In order to suppress thermal expansion of the wafer, a plurality of grooves are dug in the suction surface of the chuck, and a measure is taken to fill the grooves with a heat transfer gas such as He gas. By releasing heat from the wafer to the chuck via the gas, thermal expansion of the wafer can be suppressed.

The parameters for determining the amount of heat transferred to the chuck by the gas include the thermal conductivity of the gas, the gas pressure,
There is a gap length and the like. For example, when the gas pressure is so low that the mean free path of the gas molecule is sufficiently longer than the gap length, the thermal conductivity of the gas increases almost in proportion to the gas pressure. However, when the mean free path is shorter than the gap length, the thermal conductivity becomes less dependent on gas pressure. On the other hand, since this processing apparatus is in a reduced-pressure atmosphere, if the gas pressure in the gap between the chuck and the wafer increases, the attraction force of the wafer to the chuck decreases, and in the worst case, the wafer comes off. For this reason, the pressure of the sealing gas must be sufficiently smaller than the suction force of the wafer. From the gas pressure estimated here, the mean free path of the molecule is obtained. Therefore, it is preferable that the length of the gap between the Si wafer and the chuck is designed to be the same as the mean free path obtained here.

However, when this measure is taken, especially when dirt or dust adheres to the back surface of the wafer or when the flatness or flatness of the wafer itself is not good, the heat transfer gas is evacuated from the gap between the wafer and the chuck. Leaks indoors. As a result, if the capacity of the evacuation means is not sufficient, the required degree of vacuum in the vacuum chamber cannot be maintained.

[0005]

When the wafer is exposed and the wafer is removed from the chuck, it is necessary to prevent the heat transfer gas from leaking into the vacuum chamber as much as possible. Therefore,
Before replacing the wafer, the gas in the groove of the chuck is exhausted for a sufficient time. However, this gas has penetrated into a very narrow gap and takes a long time to exhaust. This is very undesirable when considering the throughput of the exposure apparatus.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been made in consideration of the above circumstances, and has been made in consideration of the above circumstances. It is an object to provide a charged particle beam exposure apparatus and the like.

[0007]

In order to solve the above-mentioned problems, an electrostatic chuck according to the present invention is a chuck for adsorbing and fixing a substrate to be processed by electrostatic force; an introduction hole for introducing gas to a substrate adsorption surface. An exhaust hole for discharging the gas;
Further, a valve provided on the chuck for opening and closing the introduction hole and / or the exhaust hole is provided.

[0008] The stage of the present invention is a stage for mounting and moving a chuck for adsorbing and fixing a substrate to be processed by electrostatic force; a gas introduction hole for introducing a gas into the chuck, and an exhaust hole for discharging the gas. Further, a valve attached to the chuck or the stage for opening and closing the introduction hole and / or the exhaust hole is provided.

A substrate processing apparatus according to the present invention comprises: a vacuum chamber evacuated and evacuated; a movable stage disposed in the chamber; and a chuck mounted on the stage for attracting and fixing a substrate to be processed by electrostatic force. A gas supply system that introduces a heat transfer gas into a gap between the chuck and the substrate to be processed; and an exhaust system that discharges a heat transfer gas from the gap. And / or an exhaust valve of the exhaust system is attached to the chuck or the stage.

A charged particle beam exposure apparatus according to the present invention is a charged particle beam exposure apparatus comprising: an optical system for forming an image of a charged particle beam on a sensitive substrate; and a sensitive substrate chamber for placing the sensitive substrate in a vacuum atmosphere. A movable stage disposed in the sensitive substrate chamber; a chuck mounted on the stage, for adsorbing and fixing the sensitive substrate by electrostatic force; and a heat transfer gas in a gap between the chuck and the sensitive substrate. And an exhaust system for discharging heat transfer gas from the gap, wherein the gas introduction valve of the air supply system and / or the exhaust valve of the exhaust system are attached to the chuck or the stage. It is characterized by having been done.

According to the device manufacturing method of the present invention, in the lithography step, when the heat-sensitive gas is attracted to the chuck by electrostatic force while the heat-transfer gas is supplied to the gap between the chuck and the sensitive substrate, the supply of the heat-transfer gas is performed. A system gas introduction valve and / or an exhaust valve of the gas exhaust system are attached to the chuck or a stage on which the chuck is mounted, and after supplying the heat transfer gas, the exhaust valve is used at the time of the substrate processing. It is characterized in that, at the same time as closing, the downstream side of the exhaust valve of the exhaust system piping is evacuated to vacuum.

In the present invention, the gas valve is attached to a chuck or a stage. Here, “attached” means “directly or closely attached”
That is. Since the gas valve is arranged near the chuck in this way, when supplying heat transfer gas to the gap between the chuck and the substrate, when performing substrate processing such as exposure, close the exhaust valve of the exhaust system and close the exhaust pipe. The downstream side can be evacuated. When exhausting the heat transfer gas after completion of the substrate processing step, when the exhaust valve is opened, the heat transfer gas filled between the substrate and the chuck becomes a buffer in the space of the exhaust pipe already evacuated. The gas in the gap between the chuck and the wafer can be quickly exhausted. Further, the absolute amount of gas to be exhausted is also limited to the amount existing in a portion on the chuck side from the valve. Therefore, the heat transfer gas can be quickly exhausted at the time of substrate exchange, and the substrate exchange can be performed in a short time, thereby increasing the throughput.

In the present invention, it is preferable that an exhaust pump is also connected to the air supply system on the upstream side of the gas introduction valve. When the heat transfer gas is exhausted, the exhaust pump can also be operated to exhaust the gas from the gas introduction system. Alternatively, as in the case of the exhaust system, at the time of substrate processing after the supply of the heat transfer gas, the gas introduction valve may be closed and the upstream side of the gas introduction valve of the gas introduction pipe may be evacuated. By doing so, when the gas introduction valve is opened, the heat transfer gas filled in the gap between the chuck and the wafer can be quickly exhausted.

In the present invention, it is preferable to have a sensor for monitoring the pressure on the upstream side of the gas introduction valve of the air supply system. The heat transfer gas is supplied while measuring the pressure with this sensor, and when it is confirmed that the desired pressure has been reached, the introduction / exhaust valve is closed and processing such as wafer exposure is performed. At the time of exhaust, the upstream side of the gas introduction valve of the air supply system is evacuated, and when the pressure becomes equal to or lower than a predetermined value, the gas introduction valve is opened and air can be exhausted from the air supply system.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an outline of an exposure apparatus according to a first embodiment of the present invention. In the drawings, the chamber 1, the chuck 9, the wafer 11, and the like are shown as schematic cross-sectional views, and the supply system and exhaust system for the heat transfer gas in the lower part of the figure are shown as piping diagrams.

The charged particle beam exposure apparatus includes a wafer chamber (vacuum chamber) 1 and an optical lens barrel 15. The stage 7 and the chuck 9 are housed in the wafer chamber 1. The charged particle beam source (electron gun 1
4) is disposed.
The charged particle beam bundle CPB emitted from the charged particle beam source 14 is converged and deflected through the optical system 13 and forms an image on the surface (upper surface) of the wafer (sensitive substrate) 11 to be processed.

A chamber exhaust device 5 including a vacuum pump is connected to the lower right of the chamber 1 in the drawing. In the same device 5, the inside of the chamber 1 is evacuated and evacuated. A chamber vacuum gauge 3 is attached to the upper right of the figure. The inside of the chamber 1 has a predetermined degree of vacuum (for example, 1.3
× 10 ⁻³ Pa (10 ⁻⁵ Torr)).

A stage 7 arranged in the chamber 1 has a chuck 9 mounted thereon and moves in the chamber 1. Chuck 9 placed on the upper surface of stage 7
A groove (gap) 27 dug down toward the lower side of the paper is formed on the suction surface (upper surface) of. The gap 27 between the wafer 11 and the chuck 9 is filled with He gas as a heat transfer gas. By releasing heat from the wafer 11 to the chuck 9 via this gas, thermal expansion of the wafer 11 can be suppressed. An electrode (not shown) is embedded in the chuck 9, and when a voltage is applied to this electrode, an electrostatic force is generated between the chuck 9 and the wafer 11, and the attracted surface (lower surface) of the wafer 11 Is attracted to the upper surface of the chuck 9.

Next, the heat transfer gas supply system will be described. A gas introduction hole 17 is provided at the center of the chuck 9. The gas introduction hole 17 penetrates through the chuck 9 and the stage 7 and reaches the lower surface of the stage 7. A gas introduction valve 19 is provided on the exit side of the stage 7 of the gas introduction hole 17.
Is attached. This gas introduction valve 19 is directly attached to the structure of the stage 7. Gas introduction valve 19
The gas introduction pipe 21 is connected to the end (below the figure). The gas inlet pipe 21 has a gas inlet pipe gauge (sensor).
23 are attached.

A three-way valve 25 is provided upstream of the gas introduction pipe 21.
The gas flow controller 31 is connected via the.
A gas supply source (gas cylinder) 32 is connected upstream of the gas flow controller 31. He gas is stored in the cylinder 32. Heat transfer gas chuck 9
When supplying the gas, the gas flow controller 31 is controlled so that the pressure of the gas introduction pipe gauge 23 becomes a desired value. The target value of the pressure in the gap 27 between the chuck 9 and the wafer 11 is, for example, 1.3 kPa (10 Torr). This target value is determined in consideration of the balance between the electrostatic force between the chuck 9 and the wafer 11.

Another port of the three-way valve 25 has an exhaust pump 2
9 is connected. At the time of gas exhaust, the three-way valve 25 is switched to the exhaust pump 29 side (the gas flow controller 3).
The first side is closed), and the gas can be exhausted also from the gas introduction pipe 21.

Next, the heat transfer gas exhaust system will be described. Gas exhaust holes 33 are provided at the left and right corners of the chuck 9. After the gas exhaust holes 33 merge into one in the chuck 9, they penetrate the stage 7 and reach the lower surface of the stage 7. A gas exhaust valve 35 is attached downstream of the gas exhaust hole 33. This gas exhaust valve 35
Are directly attached to the structure of the stage 7. A gas exhaust pipe 37 is connected to the end of the gas exhaust valve 35 (below the figure). The gas exhaust pipe 37 has a gas exhaust pipe gauge 3
9 is attached. Further, an exhaust pump 41 is connected to a downstream end of the exhaust pipe 37.

Next, the operation of the gas supply system and the exhaust system in the electrostatic chuck 9 of the present embodiment will be described. First, when there is no wafer 11 on the chuck 9, both the gas introduction valve 19 and the gas exhaust valve 35 are closed. Wafer 1 to be processed
When 1 is placed on the chuck 9, an electric current is supplied to an electrode (not shown), and the wafer 11 is sucked. Next, the gas is filled into the gap 27 from the gas cylinder 32 through the gas flow controller 31, the three-way valve 25, the gas introduction pipe 21, the gas introduction valve 19, and the gas introduction hole 17. At this time, gas introduction pipe gauge 2
In step 3, the gas flow rate of the gas flow rate controller 31 is controlled while monitoring the gas pressure in the gap 27. The exhaust pump 29 is shut off by the three-way valve 25. After the start of the exposure, the gas leakage is continuously supplied from the gas introduction pipe 21 to the gap 27. The exhaust valve 35 is always closed during exposure. The exhaust pump 41 is always operated. At this time, the inside of the gas exhaust pipe 37 is 1.3 × 10 ⁻¹ Pa (10 ⁻³ Torr).
r) Apply a vacuum of at least about

When exchanging the wafer 11 after the exposure is completed, the following is performed. First, the gas introduction valve 19 is closed, the gas flow controller 31 side of the three-way valve 25 is closed, and the exhaust pump 29 side is opened. Then, the exhaust pump 29 is operated. On the exhaust side, gas exhaust valve 3
When the opening 5 is opened, the He gas filled in the gap 27 between the wafer 11 and the chuck 9 is quickly exhausted by the action of the vacuum buffer in the gas exhaust pipe 37. Further, the fact that the pressure of the gas introduction pipe 21 has sufficiently decreased is indicated by the gas introduction pipe gauge 2.
When the confirmation is made in step 3, the gas introduction valve 19 is also opened.

Next, a second embodiment of the present invention will be described. In the first embodiment of the present invention, during the exposure, the gas introduction valve 1 is used.
9 is left open, and the gas leakage is always replenished from the gas introduction pipe 21. However, if gas leakage from the gap 27 does not pose a problem during wafer exposure, it is not necessary to open the gas introduction valve 19.

Therefore, in the case of the present embodiment, when the pressure in the gap 27 reaches a desired pressure, the gas introduction valve 19 is closed. Next, the three-way valve 25 is switched to the exhaust pump 29 side, and the inside of the gas introduction pipe 21 is 1.3 as in the gas exhaust pipe 37.
A vacuum of about × 10 ⁻¹ Pa (10 ⁻³ Torr) or more is drawn. Then, simultaneously with the completion of the exposure, both the gas exhaust valve 35 and the gas introduction valve 19 are opened. Then, the He gas filled in the gap 27 is rapidly exhausted by the action of the vacuum buffers in both the gas exhaust pipe 37 and the gas introduction pipe 21.

Next, an embodiment of a device manufacturing method using the above charged particle beam exposure apparatus will be described. FIG. 2 shows a flow of manufacturing micro devices (semiconductor chips such as ICs and LSIs, liquid crystal panels, CCDs, thin-film magnetic heads, micro machines, etc.).

In step 1 (circuit design), a circuit of a semiconductor device is designed. Step 2 (mask fabrication) forms a mask on which the designed circuit pattern is formed. At this time, beam blur due to the proximity effect or the space charge effect may be corrected by locally resizing the pattern. Step 3 (wafer manufacturing)
Then, a wafer is manufactured using a material such as silicon.

In step 4 (oxidation), the surface of the wafer is oxidized. Step 5 (CVD) forms an insulating film on the wafer surface. Step 6 (electrode formation) forms electrodes on the wafer by vapor deposition. Step 7 (ion implantation) implants ions into the wafer. In step 8 (resist processing), a photosensitive agent is applied to the wafer. In step 9 (electron beam exposure), the circuit pattern of the mask is printed and exposed on the wafer by the electron beam transfer device using the mask created in step 2. that time,
The above-described apparatus-method is used to exhaust the heat transfer gas filled in the gap between the wafer and the chuck. In step 10 (light exposure), the circuit pattern of the mask is printed and exposed on the wafer by an optical stepper using the light exposure mask similarly formed in step 2. Before or after this, proximity effect correction exposure for equalizing the backscattered electrons of the electron beam may be performed.

In step 11 (development), the exposed wafer is developed. In step 12 (etching), portions other than the resist image are selectively removed. Step 13
In (resist removal), the unnecessary resist after etching is removed. By repeating steps 4 to 13, multiple circuit patterns are formed on the wafer.

Step 14 (assembly) is referred to as a post-process, and is a process of forming a semiconductor chip using the wafer produced by the above process, and includes an assembly process (dicing and bonding) and a packaging process (chip encapsulation). And the like. In step 15 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 14 are performed. Through these steps, a semiconductor device is completed and shipped (step 16).

[0032]

As is apparent from the above description, according to the present invention, the heat transfer gas filled in the gap between the chuck and the substrate (wafer) can be quickly exhausted, and the wafer can be quickly replaced. As a result, the throughput can be improved.

[Brief description of the drawings]

FIG. 1 is a view showing an outline of an exposure apparatus according to a first embodiment of the present invention.

FIG. 2 shows a flow of manufacturing a micro device (a semiconductor chip such as an IC or an LSI, a liquid crystal panel, a CCD, a thin film magnetic head, a micromachine, or the like).

[Explanation of symbols]

Reference Signs List 1 chamber 3 chamber vacuum gauge 5 chamber exhaust device 7 stage 9 chuck 11 wafer 14 charged particle beam source 13 charged particle beam optical system 15 optical column 17 gas inlet hole 19 gas inlet valve 21 gas inlet tube 23 gas inlet tube gauge 25 three-way Valve 27 Gap (groove) between wafer and chuck 29 Exhaust pump 31 Gas flow controller 32 Gas cylinder 33 Gas exhaust hole 35 Gas exhaust valve 37 Gas exhaust pipe 39 Gas exhaust pipe gauge 41 Exhaust pump

Claims (9)

[Claims] 1. A chuck for adsorbing and fixing a substrate to be processed by electrostatic force; an introduction hole for introducing a gas to a substrate adsorption surface, an exhaust hole for exhausting the gas, and the introduction hole and / or exhaust gas. An electrostatic chuck comprising a valve attached to said chuck for opening and closing a hole. 2. A stage for mounting and moving a chuck for attracting and fixing a substrate to be processed by electrostatic force; a gas introduction hole for introducing a gas into the chuck; an exhaust hole for discharging the gas; A stage provided with a valve attached to said chuck or stage for opening and closing an introduction hole and / or an exhaust hole. 3. A vacuum chamber evacuated and evacuated, a movable stage disposed in the chamber, a chuck mounted on the stage, for attracting and fixing a substrate to be processed by electrostatic force, A substrate processing apparatus comprising: an air supply system for introducing a heat transfer gas into a gap with a processing substrate; and an exhaust system for discharging the heat transfer gas from the gap; Alternatively, an exhaust valve of the exhaust system is attached to the chuck or the stage. 4. A charged particle beam exposure apparatus comprising: an optical system for forming an image of a charged particle beam on a sensitive substrate; and a sensitive substrate chamber for placing the sensitive substrate in a vacuum atmosphere; A movable stage arranged on the stage, a chuck mounted on the stage, for adsorbing and fixing the sensitive substrate by electrostatic force, and an air supply system for introducing a heat transfer gas into a gap between the chuck and the sensitive substrate. An exhaust system for discharging heat transfer gas from the gap, wherein the gas introduction valve of the air supply system and / or the exhaust valve of the exhaust system are attached to the chuck or the stage. Charged particle beam exposure equipment. 5. The substrate processing apparatus according to claim 3, wherein, after supplying the heat transfer gas, the exhaust valve is closed during the substrate processing, and the downstream side of the exhaust valve of the exhaust system piping is evacuated to a vacuum. Or a charged particle beam exposure apparatus according to claim 4. 6. The substrate processing apparatus or the charged particle beam exposure apparatus according to claim 5, further comprising a sensor for monitoring a pressure upstream of the gas supply valve of the air supply system. 7. An exhaust pump is also connected to an air supply system on the upstream side of the gas introduction valve. After supplying the heat transfer gas, the gas introduction valve is closed during the substrate processing and the gas introduction pipe is closed. 5. The substrate processing apparatus according to claim 3, wherein the upstream side of the gas introduction valve is evacuated to vacuum. 8. The substrate processing apparatus or charged particle beam exposure apparatus according to claim 5, further comprising a sensor for monitoring a pressure upstream of the gas supply valve of the air supply system. 9. A gas supply valve for supplying a heat transfer gas for supplying a heat transfer gas to the chuck by electrostatic force while supplying a heat transfer gas to a gap between the chuck and the sensitive substrate in a lithography process. And / or an exhaust valve of an exhaust system for the gas is attached to the chuck or a stage on which the chuck is mounted, and after supplying the heat transfer gas, the exhaust valve is closed during the substrate processing and the exhaust system piping is provided. A method for manufacturing a device, comprising: drawing a vacuum downstream of an exhaust valve of the device.