JP2001085316A - Aligner, manufacture of device, and stage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an original plate stage and a substrate stage to be improved in synchronous control accuracy, by a method wherein when the substrate stage and the original plate stage are synchronously moved, an original plate stage measuring equipment and a substrate stage measuring equipment are arranged, so as to enable the original plate stage and the substrate stage to be driven to approach to or part from an original plate stage measuring equipment and a substrate stage measuring equipment, respectively. SOLUTION: A reticle stage laser interferometer 3 measures the displacement of a reticle stage 2 in a direction of Y, and the reticle state 2 is controlled in a direction of Y based on the measured value. A wafer stage laser interferometer 7 measures the displacement of a wafer stage 6 in a direction of Y, and the wafer stage 6 is controlled in a direction of Y based on the measured value. The laser interferomters 3 and 7 are arranged on opposite sides interposing the optical axis of a projection lens 4 between them to measure the displacements of the reticle stage 2 and the wafer stage 6 based on a length change in optical paths 14 and 15. The stages 2 and 6 are driven so as to approach to or part from the laser interferometers 3 and 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection exposure apparatus, and more particularly to an exposure apparatus for manufacturing an element by synchronously moving a stage on which a mask substrate for manufacturing an element is mounted and a stage on which a substrate such as a semiconductor wafer is mounted. Further, the present invention relates to a device manufacturing method using such an exposure apparatus. The present invention also relates to a stage device used for such an exposure apparatus, a machine tool, and the like.

[0002]

2. Description of the Related Art In a photolithography process for manufacturing a semiconductor device,
2. Description of the Related Art A semiconductor exposure apparatus that transfers a fine circuit pattern of a reticle onto a wafer coated with a photosensitive agent has been used.

In recent years, there has been an increasing demand for a larger field of an exposure area with an increase in the size of a semiconductor element, and a step-and-scan type exposure apparatus has been proposed as an exposure apparatus that meets this demand.

FIG. 5 is a schematic block diagram of a conventional step-and-scan type projection exposure apparatus.

A reticle 101 having a circuit pattern is
It is held on a reticle stage 102. The reticle stage 102 is capable of scanning and moving in the Y direction, and is also capable of minute movement in the X direction. The wafer 105 coated with the resist is held on a wafer stage 106. The wafer stage 106 is movable in the X and Y directions.

The reticle 101 is illuminated on a predetermined area by slit-shaped or arc-shaped illumination light IL having uniform illuminance. The pattern of the reticle 101 is such that the X direction (longitudinal direction) of the slit is the reduction magnification of the projection lens, and the Y direction (short direction) is the reticle stage 102 and the wafer stage 10.
6 is synchronized at the speed of the reduction ratio of the projection lens 104, and the wafer 105 for semiconductor device fabrication is synchronized.
Is projected.

Laser interferometer 103 for reticle stage
Measures the displacement of the reticle stage 102 in the Y direction, and the reticle stage 102 is controlled based on the measured value. Similarly, a wafer stage laser interferometer 10
Numeral 7 measures the displacement of the wafer stage 106 in the Y direction, and the wafer stage is controlled based on the measured value.

[0008] Laser interferometer 103 and laser interferometer 107
Are arranged in the same direction with respect to the optical axis of the projection lens 104. The laser interferometer 103 and the laser interferometer 1
07, projection lens 104 and reticle stage surface plate 1
08 is configured in the main body structure 110. Therefore, the reticle stage 102 and the wafer stage 106
Is calculated by the laser interferometer 103 and the laser interferometer 107.
The position is measured and controlled based on the main body structure 110.

Laser interferometer 103 and laser interferometer 10
7 measures the displacement of the reticle stage 102 and the wafer stage 106 by the displacement of the optical path lengths 114 and 115, respectively.

Here, the conventional laser interferometer 1 shown in FIG.
03 and the laser interferometer 107 are arranged on the same side with respect to the optical axis of the projection lens.

When performing scanning exposure, the reticle stage 10
2 and the wafer stage 106 are driven in directions opposite to each other with respect to the optical axis due to the symmetry of the projection optical system. Therefore, when reticle stage 102 is driven so as to move away from laser interferometer 103, wafer stage 106 is driven so as to approach laser interferometer 107. Conversely, when reticle stage 102 is driven closer to laser interferometer 103, wafer stage 106 is driven away from laser interferometer 107. That is, when the optical path length 114 increases, the optical path length 115 decreases, and when the optical path length 114 decreases, the optical path length 115 increases.

[0012]

The measurement of the displacement by the laser interferometer can be obtained by calculating how many wavelengths of the optical path have been displaced in units of the wavelength of the reference laser. At this time, if the temperature or atmospheric pressure in the optical path changes locally for some reason, a difference occurs between the reference laser and the wavelength of the laser in the optical path, causing an error between the calculated value and the actual displacement. Would. This measurement error increases as the optical path becomes longer.

In the conventional arrangement of the laser interferometers as described above, the increase and decrease of the optical path length of each laser interferometer are reversed. Therefore, when the reticle stage moves away from the reticle stage laser interferometer and the error of the laser interferometer increases, the error decreases on the wafer stage side, and the error of the reticle stage approaches the reticle stage laser interferometer. When it became smaller, the error was larger on the wafer stage side.

As a result, the accuracy of the synchronization control of both stages is deteriorated, and the contrast and overlay accuracy are reduced.

An object of the present invention is to improve such a problem and improve the accuracy of synchronous control of both stages, thereby improving the contrast and overlay accuracy.

[0016]

In order to achieve the above object, an exposure apparatus according to the present invention comprises: a projection optical system for projecting a pattern on an original onto a substrate at a predetermined magnification; Possible original plate stage, original plate stage measuring device for measuring the position of the original plate stage, substrate stage capable of holding and moving the substrate, and substrate stage measuring device for measuring the position of the substrate stage The original stage measurement device and the substrate stage measurement device, when moving the original plate stage and the substrate stage in synchronization, the measurement distance of the original plate stage measurement device and the measurement distance of the substrate stage measurement device, respectively It is characterized in that they are arranged so as to approach each other or away from each other.

Further, another exposure apparatus of the present invention for achieving the above object is a projection optical system which projects a pattern on an original onto a substrate at a predetermined magnification, and which is movable while holding the original. An original plate stage, an original plate stage measuring device for measuring the position of the original plate stage, a substrate stage capable of holding and moving the substrate, and a substrate stage measuring device for measuring the position of the substrate stage The original plate stage measuring device and the substrate stage measuring device are arranged on opposite sides of the optical axis of the projection optical system.

It is preferable that the exposure apparatus exposes a pattern on the original plate onto the substrate while scanning and moving the original plate and the substrate relative to the projection optical system.

Preferably, the measuring device is a laser interferometer, an ultrasonic sensor or a linear encoder.

Further, a stage apparatus according to the present invention for achieving the above object has a first stage movable in a predetermined direction and a first stage for measuring a position of the first stage in the predetermined direction. A stage measuring device, a second stage movable in a direction parallel to the predetermined direction, and a second stage for measuring a position of the second stage in a direction parallel to the predetermined direction.
The first stage measuring device and the second stage measuring device are provided with the first stage and the second stage measuring device.
When the stage is moved synchronously, the measurement distance of the first stage measurement device and the measurement distance of the second stage measurement device are arranged so as to approach each other or away from each other. I do.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS <Embodiment of Exposure Apparatus> FIG. 1 is a schematic structural view of a step-and-scan type projection exposure apparatus according to the present invention.

A reticle 1 having a circuit pattern is held on a reticle stage 2. The reticle stage 2 can scan and move on the reticle stage base 8 in the Y direction, and can also move slightly in the X direction. The wafer 5 coated with the resist is held on a wafer stage 6. The wafer stage 6 has a wafer stage table 9
Above, it is movable in the X and Y directions.

The reticle 1 is illuminated on a predetermined area by slit-shaped or arc-shaped illumination light IL having uniform illuminance. In the pattern of the reticle 1, the X direction (longitudinal direction) of the slit is the reduction magnification of the projection lens, and the Y direction (short direction).
By synchronizing the reticle stage 2 and the wafer stage 6 at the speed of the reduction magnification ratio of the projection lens 4, the reticle stage 2 and the wafer stage 6 are inverted and image-formed on the wafer 5 for producing semiconductor devices.

The reticle stage laser interferometer 3 measures the displacement of the reticle stage 2 in the Y direction, and the reticle stage 2 is controlled based on the measured value. Similarly, the wafer stage laser interferometer 7 measures the displacement of the wafer stage 6 in the Y direction, and the wafer stage is controlled based on the measured value.

Laser interferometer 3 and laser interferometer 7 of the present invention
Are arranged on the opposite side of the optical axis of the projection lens 4. The laser interferometer 3, the laser interferometer 7, the projection lens 4, and the reticle stage base 8 are
Is configured. For this reason, the positions of the reticle stage 2 and the wafer stage 6 are measured by the laser interferometer 3 and the laser interferometer 7 with reference to the main body structure 10 and controlled.

The laser interferometer 3 and the laser interferometer 7 measure the displacement of the reticle stage 2 and the wafer stage 6 based on the displacement of the optical path lengths 14 and 15, respectively. The measurement of the displacement by the laser interferometer can be obtained by calculating how many wavelengths the optical path has displaced in units of the wavelength of the reference laser. At this time, if the temperature or atmospheric pressure in the optical path changes locally for some reason, a difference occurs between the reference laser and the wavelength of the laser in the optical path, causing an error between the calculated value and the actual displacement. Would. This measurement error increases as the optical path becomes longer.

When the scanning exposure is performed by the exposure apparatus of the present invention, the laser interferometer 3 and the laser interferometer 7 are arranged on opposite sides of the optical axis of the projection lens 4, so that the two stages are respectively subjected to laser interference. It is driven to approach a total of 3, 7 or to drive away. That is, both stages are driven synchronously so that the optical path length 15 becomes smaller when the optical path length 14 becomes smaller, and the optical path length 15 becomes larger when the optical path length 14 becomes larger.

As a result, the difference between the optical path length 14 on the reticle stage 2 side and the optical path length 15 on the wafer side is reduced, and the difference in the measurement error of the laser interferometer between the two stages is reduced, thereby improving the synchronization accuracy. it can.

In this embodiment, the laser interferometer is used as the length measuring device. However, the present invention is not limited to this.
For example, an ultrasonic sensor or a linear encoder can be used.

Further, in the present embodiment, the main body structure 10 holding the projection lens 4 and the wafer stage base 9 are vibrationally independent by the damper 12, but the invention is not limited to this. As described above, the main body structure and the wafer stage base may be formed substantially integrally.

<Device Manufacturing Method> Next, an embodiment of a method of manufacturing a semiconductor device using the above-described exposure apparatus will be described.

FIG. 3 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. Step 2 is a process for making a mask on the basis of the circuit pattern design.
In step 3 (wafer manufacture), a wafer 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,
This is a process of forming a semiconductor chip using the wafer produced in step 14, and includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). In step 6 (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 S7).

FIG. 4 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. 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 print and expose the circuit pattern of the mask onto the wafer. Step 17 (development) develops the exposed wafer. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), unnecessary resist after etching is removed. 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.

[0034]

According to the exposure apparatus of the first or second aspect of the present invention, the difference between the measurement lengths when measuring the two stages is reduced, so that the synchronization accuracy can be improved.

Further, according to the exposure apparatus of the third aspect of the present invention, the scanning movement of the stage at the time of scanning exposure can be performed with high precision.

[Brief description of the drawings]

FIG. 1 is a schematic view of an exposure apparatus of the present invention.

FIG. 2 is a schematic view of another exposure apparatus of the present invention.

FIG. 3 is a flow chart of manufacturing a semiconductor device.

FIG. 4 is a wafer process flow diagram.

FIG. 5 is a schematic view of a conventional exposure apparatus.

[Explanation of symbols]

 Reference Signs List 1 reticle 2 reticle stage 3 reticle stage laser interferometer 4 projection lens 5 wafer 6 wafer stage 7 wafer stage laser interferometer 8 reticle stage base 9 wafer stage base 10 body structure

Claims (6)

[Claims] 1. An exposure apparatus for exposing a pattern on an original onto a substrate, comprising: a projection optical system for projecting the pattern on the original onto the substrate at a predetermined magnification; and an original stage movable while holding the original. An original plate stage measuring device for measuring the position of the original plate stage, a substrate stage capable of holding and moving the substrate, and a substrate stage measuring device for measuring the position of the substrate stage; The stage measurement device and the substrate stage measurement device, when moving the original plate stage and the substrate stage in synchronization, the measurement distance of the original plate stage measurement device and the measurement distance of the substrate stage measurement device, respectively, or, An exposure apparatus, wherein the exposure apparatuses are arranged to be away from each other. 2. An exposure apparatus for exposing a pattern on an original onto a substrate, comprising: a projection optical system for projecting the pattern on the original onto the substrate at a predetermined magnification; and an original stage movable while holding the original. An original plate stage measuring device for measuring the position of the original plate stage, a substrate stage capable of holding and moving the substrate, and a substrate stage measuring device for measuring the position of the substrate stage; An exposure apparatus, wherein a stage measuring device and the substrate stage measuring device are arranged on opposite sides of an optical axis of the projection optical system. 3. The exposure apparatus according to claim 1, wherein a pattern on the original plate is exposed on the substrate while the original plate and the substrate are moved relative to the projection optical system by scanning. 4. The exposure apparatus according to claim 1, wherein the measuring device is a laser interferometer, an ultrasonic sensor, or a linear encoder. 5. A step of applying a photosensitive agent to a substrate, a step of scanning and exposing a pattern on an original plate onto the substrate using the exposure apparatus according to claim 1, and a step of developing the exposed substrate. A device manufacturing method comprising: 6. A first stage movable in a predetermined direction, a first stage measuring device for measuring a position of the first stage in the predetermined direction, and moving in a direction parallel to the predetermined direction. A possible second stage, and a second stage measuring device for measuring a position of the second stage in a direction parallel to the predetermined direction, wherein the first stage measuring device and the second stage measuring device The stage measuring instrument
When the first stage and the second stage are moved in synchronization with each other, the measurement distance of the first stage measurement device and the measurement distance of the second stage measurement device become closer or farther away, respectively. A stage device, wherein the stage device is arranged in a stage.