JP2002367898A - Stage apparatus, exposure apparatus, exposure method, and device manufacturing method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To prevent disturbance of an air supply line from entering an air cylinder for self-weight compensation. SOLUTION: A Z stage 1 holding a wafer or the like is supported by its own weight by air cylinders 3a to 3c, and performs vertical movement such as focusing by linear motors 4a to 4c. During exposure, the electromagnetic valves 6a to 6c are temporarily closed to cut off the air supply line in order to avoid a disturbance due to a pressure change of a pressure source of the air supply line or a characteristic change of the air regulators 5a to 5c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stage device, an exposure apparatus, an exposure method, and a device manufacturing method used for a semiconductor manufacturing apparatus or the like.

[0002]

2. Description of the Related Art In an XY stage or the like of a semiconductor exposure apparatus, the Z direction is adjusted in the vertical direction for focus adjustment and in order to avoid contact with a transfer system hand when loading / unloading a wafer from / to a stage. Has a movable mechanism. A linear motor is used for controlling the vertical drive.

However, if the drive in the Z direction is to be performed only by a linear motor, a linear motor having an extremely large thrust is necessary to support the weight of the stage. In addition to this, a complicated control mechanism for performing very delicate control such as focusing must be provided, which leads to an increase in power consumption and an increase in apparatus cost.

Therefore, in the conventional stage device, by providing a mechanism for compensating its own weight in the Z direction, it is possible to use a small linear motor having a thrust for driving only a displacement from a default position. In addition, this method enables fine position control in the Z direction.

[0005] Generally, an air cylinder is used to compensate for its own weight, and the pressure to the air cylinder is adjusted and controlled by a regulator to maintain a default position.

[0006]

However, according to the above prior art, air is always supplied to the air cylinder for compensating its own weight in the Z direction, and the air cylinder expands and contracts when driven in the Z direction. Since the internal volume changes due to the operation, an air regulator is provided at the front stage of the air cylinder to compensate for this change and maintain a constant pressure. Is kept constant.

However, the pressure supplied to the air cylinder may change repeatedly in a very small range due to a characteristic change of the regulator or a large change in the pressure of the air supply source. This pressure change becomes a disturbance that adversely affects the control characteristics in the Z direction, and causes the stage accuracy to deteriorate.

In addition, since the air regulator performs feedback control by itself and functions so as to keep the pressure on the output side constant, in the mechanism using the air cylinder as described above, even if the air cylinder is damaged, , There is no way to detect it.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned unsolved problems of the prior art, and the stage performance is changed by a pressure change of a supply source of air or the like for self-weight compensation or a characteristic change of an air regulator or the like. It is an object of the present invention to provide a highly accurate and highly reliable stage apparatus, exposure apparatus, exposure method, and device manufacturing method that do not deteriorate.

[0010]

In order to achieve the above object, a stage apparatus according to the present invention comprises a holding plate having a holding surface, a fluid pressure cylinder for supporting the holding plate and generating a fluid pressure for self-weight compensation. A driving unit for driving the holding plate in the vertical direction, a fluid pressure supply system for supplying a working fluid to the fluid pressure cylinder, and the fluid pressure supply system temporarily keeping the fluid pressure of the fluid pressure cylinder. It is characterized by having a shut-off means for shutting off the power.

The shut-off means may have a solenoid valve or a pneumatic valve.

The solenoid valve or the pneumatic valve of the shut-off means is preferably of a self-holding type.

Preferably, the driving means has an electromagnetic actuator.

An exposure apparatus according to the present invention is characterized by having the above stage apparatus and exposure means for exposing a substrate held by the stage apparatus.

The exposure method according to the present invention is characterized in that, in the exposure apparatus described above, the substrate is exposed, and the fluid pressure supply system and the fluid pressure cylinder are temporarily disconnected.

[0016]

The holding plate is compensated for its own weight by a fluid pressure cylinder, and is vertically moved for focusing by an electromagnetic actuator such as a linear motor. During exposure of a substrate such as a wafer, the fluid pressure of the fluid pressure cylinder is controlled in order to prevent disturbances such as pressure changes in the supply source of air, which is a working fluid, and fluctuations in the characteristics of the air regulator etc. While maintaining the above condition, the fluid pressure supply system is temporarily disconnected from the fluid pressure supply system by a shutoff means such as an electromagnetic valve or a pneumatic valve.

By using such a stage device for a wafer stage or the like of an exposure apparatus, transfer deviation or the like due to disturbance can be effectively avoided, and transfer accuracy can be greatly improved.

Another advantage is that trouble such as breakage of the fluid pressure cylinder can be easily detected by driving the electromagnetic actuator and measuring the drive current (operating amount) with the fluid pressure supply system disconnected.

[0019]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a stage device (wafer stage) of an exposure apparatus according to an embodiment, which comprises a Z stage 1 which is a holding plate having a holding surface 1a for holding a wafer as a substrate, and a drawing. An XY stage 2 having a large stroke moving mechanism, a first to third air cylinders 3a to 3c, which are fluid pressure cylinders for automatic compensation, disposed between the XY stage 2 and the Z stage 1, and driven. And linear motors 4a to 4c as first to third electromagnetic actuators,
4c is composed of a stator fixed on the XY stage 2 and a mover fixed to the lower surface of the Z stage 1 so as to face these.

Each of the linear motors 4a to 4c controls the position of the Z stage 1 in the vertical direction by Lorentz force acting between the stator and the mover. Is positioned on the wafer. At this time, the weight of the Z stage 1 is 3
The fluid pressures of the individual air cylinders 3a to 3c cancel each other.

The XY stage 2 moves a wafer for printing a circuit pattern on the Z stage 1 in the X and Y directions. An air supply line, which is a fluid pressure supply system for supplying air as a working fluid to the air cylinders 3a to 3c for compensating the weight of the Z stage 1, has an air regulator for adjusting the air cylinder pressure (fluid pressure). 5a ~
5c, solenoid valves 6a to 6c serving as shut-off means for temporarily separating the air supply line and the air cylinder, a manifold 7 for branching a pressure source of air, and a position sensor (not shown) for measuring position data in the Z direction. And a pressure sensor 8a to 8c for measuring a fluid pressure, a current detection unit 9 for detecting a drive current as an operation amount of each of the linear motors 4a to 4c, and a controller 10.

In a normal state, the solenoid valves 6a to 6c are open, and air is supplied to each of the air cylinders 3a to 3c.

As described above, air is supplied to each of the air cylinders 3a to 3c for compensating the weight in the Z direction, and each linear motor 4
a to 4c are driven to perform fine adjustment of the position of the wafer on the Z stage 1 in the Z direction, that is, focusing, and then irradiate exposure light through a projection lens system or the like to print a circuit pattern. However, during exposure, when a pressure change of a pressure source of an air supply line for supplying air to the air cylinders 3a to 3c or a disturbance due to a characteristic change of the air regulators 5a to 5c propagates to each of the air cylinders 3a to 3c. As shown in FIG. 2A, the vibration becomes minute vibration in the Z direction, deteriorating the focus position control characteristic of the Z stage 1, and lowering the transfer accuracy of the exposure apparatus.

Therefore, Z by the linear motors 4a to 4c
After the focusing of the stage 1 is completed, the solenoid valves 6a to 6c are temporarily closed as shown in FIG. 2B, so that the pressure sources of the air supply lines and the air regulators 5a to 5c during exposure. Disturbance caused by each air cylinder 3a ~
3c. After the exposure, each solenoid valve 6a
6c and return to the state shown in FIG. 2A to prepare for the next step such as loading and unloading a wafer.

FIG. 3 shows the solenoid valves 6a-6 of each air supply line.
It is a flowchart which shows the control process of c. As shown in FIG. 3A, a wafer is loaded onto the holding surface 1a of the Z stage 1 in step 101, and XY is
Step movement by driving the stage 2 and focusing by the linear motors 4a to 4c are performed. At this time, the solenoid valves 6a to 6c of each air supply line for performing the self-weight compensation of the Z stage 1 are in an open state. Next, in step 103, each of the solenoid valves 6a to 6c is closed to disconnect the air cylinders 3a to 3c from the air supply line. In step 104, each shot (exposure area) of the wafer is exposed. It is determined whether or not the exposure of all shots has been completed.
6c is opened to reconnect each of the air cylinders 3a to 3c with the air supply line. If there is an unexposed shot, the step moves to the next shot in step 106.

Alternatively, as shown in FIG. 3B, exposure is performed in step 104, and the electromagnetic valves 6a to 6c are opened in step 115 to start supplying air to the air cylinders 3a to 3c. It is also possible to confirm that the exposure of all shots has been completed in step 116, and if there is an unexposed shot, step 117 moves to the next shot and returns to step 103.

A pneumatic valve may be used instead of the solenoid valves 6a to 6c. Further, the pneumatic valves and the solenoid valves 6a to 6c are self-holding type, and even if they are closed, the air regulators 5a to 6c are closed.
No change occurs in the holding force of 5c.

Thus, while performing the same function as an air regulator as in the prior art, the influence of air pressure turbulence is not exerted on the stage performance during exposure, and the reliability of the stage control can be greatly improved.

The control of the solenoid valve in the flow of FIG.
The exposure and the driving of the XY stage 2 are performed in synchronization with the controller 10 of the exposure apparatus. For this reason, it is possible to control so as not to cause a decrease in throughput or the like by avoiding a timing that adversely affects the driving of the stage.

The solenoid valves 6a to 6c are connected to the air cylinder 3
Since each of a to 3c is individually prepared and can be individually controlled, the cause when there is a disturbance can be specified as follows.

When vibration in the Z direction is generated, the solenoid valves 6a to 6c are opened and closed individually or in plural combinations in order, and the vibration and behavior in the Z direction at that time are not shown by position sensors or pressure sensors 8a to 8c. To detect. This allows
If noise vibration is generated from a specific axis, it can be detected and specified, and it is easy to find a countermeasure. Further, it is also possible to select and open / close only a necessary solenoid valve according to the situation.

Further, the position of the Z stage 1 in the Z direction is controlled by the linear motors 4a to 4c, and the current supplied to each of them is individually measured by the current detector 9. Therefore,
If any of the air cylinders 3a to 3c is damaged or air leaks along the way, the solenoid valve 6a
By monitoring the current value obtained from the current detection unit 9 in a state where .about.6c is closed, an air leak state can be detected.

More specifically, when the solenoid valve is normally closed, the solenoid valves 6a to 6c are connected to the air cylinders 3a to 3c.
The linear motor servo current for maintaining the steady state does not change significantly. Therefore, the servo current when the solenoid valve is closed and the stage is kept in a steady state is measured, and if there is a change in the current, it can be determined that there is air leakage. In addition, the linear motors 4a to
By monitoring each servo current of 4c individually,
It is easy to specify which of the linear motors 4a to 4c has a problem, and it is possible to contribute to an early solution of the trouble.

According to the present embodiment, in the stage control of the exposure apparatus, disturbance due to air modulation can be prevented, and the accuracy and characteristics of the stage control can be improved. Another advantage is that it is easy to specify the cause when a disturbance occurs and the cause when a failure occurs.

Next, an embodiment of the device manufacturing method will be described. FIG. 4 shows a manufacturing flow of a semiconductor device (a semiconductor chip such as an IC or an LSI, or a liquid crystal panel or a CCD). In step 1 (circuit design), the circuit of the semiconductor device is designed. In step 2 (mask fabrication), a mask (reticle) as an original on which the designed circuit pattern is formed is fabricated. In step 3 (wafer manufacturing), a wafer as a substrate is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the prepared mask and wafer. 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 includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). . Step 6
In (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 5 shows a detailed flow of the above 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. In step 14 (ion implantation), ions are implanted into the wafer. Step 15
In (resist processing), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses the above-described exposure apparatus to expose a circuit pattern on the mask onto the wafer by printing. Step 17 (development) develops the exposed wafer. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist removal), unnecessary resist after etching is removed by the above-described substrate processing method. By repeating these steps, multiple circuit patterns are formed on the wafer. By using the manufacturing method of this embodiment, it is possible to manufacture a highly integrated semiconductor device, which has been conventionally difficult to manufacture.

[0038]

Since the present invention is configured as described above, the following effects can be obtained.

The disturbance caused by the pressure source of the air cylinder and the air regulator for self-weight compensation can be cut off, and the stability and reliability of the stage position control during exposure can be greatly improved.

By using such a stage device,
The transfer accuracy of the exposure apparatus can be improved, and higher definition and lower cost of semiconductor devices can be promoted.

[Brief description of the drawings]

FIG. 1 is a diagram showing a stage device according to one embodiment.

FIG. 2 is a diagram illustrating a state in which an electromagnetic valve is opened and a state in which it is closed.

FIG. 3 is a flowchart showing a timing for opening and closing a solenoid valve.

FIG. 4 is a flowchart showing a semiconductor manufacturing process.

FIG. 5 is a flowchart showing a wafer process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Z stage 2 XY stage 3a-3c Air cylinder 4a-4c Linear motor 5a-5c Air regulator 6a-6c Solenoid valve 7 Manifold 8a-8c Pressure sensor 9 Current detector 10 Controller

Claims (8)

[Claims] 1. A holding plate having a holding surface, a fluid pressure cylinder that supports the holding plate and generates a fluid pressure for self-weight compensation, a driving unit that drives the holding plate in a vertical direction, and the fluid pressure cylinder. A fluid pressure supply system for supplying a working fluid to the
A stage apparatus having a shutoff means for temporarily shutting off the fluid pressure supply system while maintaining the fluid pressure of the fluid pressure cylinder. 2. The stage device according to claim 1, wherein the shut-off means includes a solenoid valve or a pneumatic valve. 3. The stage device according to claim 2, wherein the solenoid valve or the pneumatic valve of the shutoff means is a self-holding type. 4. The stage device according to claim 1, wherein the driving means has an electromagnetic actuator. 5. An exposure apparatus comprising: the stage device according to claim 1; and exposure means for exposing a substrate held by the stage device. 6. The exposure method according to claim 5, wherein a part between the fluid pressure supply system and the fluid pressure cylinder is temporarily disconnected during exposure of the substrate. 7. The exposure apparatus according to claim 5, wherein an operation amount of the drive unit is measured by temporarily operating the fluid pressure supply system and the fluid pressure cylinder in a state where the fluid pressure supply system and the fluid pressure cylinder are disconnected. Exposure method characterized by detecting the following. 8. A device manufacturing method comprising a step of manufacturing a device by the exposure method according to claim 6.