WO2011072597A1

WO2011072597A1 - Dual silicon wafer stage exchange method and system for lithographic apparatus

Info

Publication number: WO2011072597A1
Application number: PCT/CN2010/079759
Authority: WO
Inventors: 朱煜; 张鸣; 徐登峰; 汪劲松; 董立立; 杨开明; 尹文生; 胡金春; 许岩; 马竞; 田丽; 李玉洁; 王婧
Original assignee: 清华大学
Priority date: 2009-12-15
Filing date: 2010-12-14
Publication date: 2011-06-23
Also published as: CN101718959B; CN101718959A

Abstract

A dual silicon wafer stage exchange system for a lithographic apparatus includes a base stage (5), two silicon wafer stages (3,8), two X-direction linear guide rails (2,6), two Y-direction linear guide rails (4, 9), two silicon wafer stage auxiliary drive units (11,12), and four single-freedom auxiliary drive units (1,7,15,16). The system further comprises two main drive units (10, 13). Under the driving of the main drive units, the Y-direction linear guide rails can realize the movement along the X direction and the rotary motion in the plane of the base stage; the two Y-direction linear guide rails rotate until they do not interfere with each other when move along the X direction, and then the two Y-direction linear guide rails move towards each other along the X direction together with the silicon wafer stages; when the two Y-direction linear guide rails change to move in the opposite directions, the two Y-direction linear guide rails rotate in the opposite directions, thereby achieving the position exchange of the two wafer stages. A dual silicon wafer stage exchange method for the lithographic apparatus is also disclosed. The system not only avoids the defects of consistency of size of silicon wafer stages and extremely high precision requirements of processing and assembling parts, but also shortens exchange time, simplifies system structure, and improves the efficiency, spatial utilization rate and precision of the system.

Description

[Invention name established by ISA according to Rule 37.2] Method and system for exchanging dual silicon wafer table of lithography machine

The invention relates to an efficient lithography machine dual silicon wafer exchange system, which is applied to a semiconductor lithography machine and belongs to the technical field of semiconductor manufacturing equipment.

In the production process of integrated circuit chips, the exposure design (lithography) of the chip design pattern on the photoresist on the surface of the silicon wafer is one of the most important processes. The device used in this process is called a photolithography machine. machine). The resolution and exposure efficiency of the lithography machine greatly affect the feature line width (resolution) and productivity of the integrated circuit chip. The motion precision and working efficiency of the silicon ultra-precision motion positioning system (hereinafter referred to as the silicon wafer system), which is the key system of the lithography machine, largely determine the resolution and exposure efficiency of the lithography machine.

The basic principle of the step-and-scan projection lithography machine is shown in Figure 1. The deep ultraviolet light from the light source 26 passes through a reticle 27 and a lens system 28 to image a portion of the pattern on the reticle on a particular chip of the silicon wafer 29. The reticle and the silicon wafer are reversely moved at a certain speed ratio, and finally all the patterns on the reticle are imaged on the chip of the silicon wafer.

The basic function of the wafer stage motion positioning system is to carry the silicon wafer during the exposure process and move at a set speed and direction to achieve accurate transfer of the mask pattern to various areas of the wafer. Since the line width of the chip is very small (the minimum line width has reached 45 nm at present), in order to ensure the engraving precision and resolution of the lithography, the wafer stage must have a very high motion positioning accuracy; in addition, the movement of the wafer stage Speed greatly affects the productivity of lithography, so it is necessary to continuously increase the speed of the wafer stage to increase productivity.

Traditional wafer stage, such as patent EP 0729073 and patent US As described in 5996437, there is only one wafer motion positioning unit in the lithography machine, that is, a silicon wafer stage. Preparations such as leveling and focusing are done on top of it. These tasks take a long time, especially alignment, due to the requirement for extremely high-speed low-speed scanning (typical alignment scan speed is 1). Mm/s), so it takes a long time. It is very difficult to reduce the working time. In order to improve the production efficiency of the lithography machine, it is necessary to continuously increase the moving speed of the stepping and exposure scanning of the wafer stage. The increase of speed will inevitably lead to the deterioration of the dynamic performance of the system. Therefore, a large number of technical measures are needed to ensure and improve the motion accuracy of the wafer stage, and the cost to maintain the existing precision or achieve higher precision will be greatly improved. .

The structure described in the patent W098/40791 (publication date: 1998.9.17; country: the Netherlands) adopts a dual silicon wafer stage structure, and the exposure preparation work of upper and lower sheets, pre-alignment, alignment, etc. is transferred to the second wafer stage. Up and independently moving simultaneously with the exposed wafer stage. Under the premise of not increasing the moving speed of the silicon wafer stage, a large amount of preparation work for the exposed silicon wafer stage is shared by the second silicon wafer stage, thereby greatly shortening the working time of each silicon wafer on the exposed silicon wafer stage, and greatly improving Production efficiency. However, the main drawback of this system is the non-centroidal drive problem of the wafer stage system.

The invention patent filed by the applicant in 2007 "a lithography machine wafer table double exchange system" (publication number: CN101101454 A dual-switching system of a lithography machine is disclosed, which has the advantages of simple structure, high space utilization, and the exposure efficiency of the lithography machine. However, the double-wafer stage system also has some problems. First, the air-floating bearing needs to exchange the guiding surface when the wafer stage is exchanged, which leads to extremely high precision requirements for the dimensional consistency of the wafer stage, and the processing and assembly of the parts. Accuracy is required to be above the micron level; secondly, it is difficult to install sensors for detecting mutual position between the guide rails involved in the exchange, and collision may occur between the linear guide rails; third, the wafer stage system is not driven by the centroid; fourth is the double silicon stage The switching efficiency and space utilization of the switching system are not high enough.

technical problem

The invention aims at the shortcomings and defects of the prior art silicon wafer stage technology, and proposes a new high efficiency with the advantages of simple structure, high exchange efficiency, high space utilization and no collision between linear guide rails during exchange. The lithography machine's dual silicon wafer exchange system can overcome the shortcomings of the existing dual silicon wafer exchange system, such as non-centroid drive, high space utilization, and high processing and assembly precision requirements, making it simple in structure and space utilization. The rate is high and there is no advantage that the linear guides collide with each other during the exchange, thereby further improving the exchange efficiency and exposure efficiency of the lithography machine.

Technical solution

The technical solution of the present invention is as follows:

The invention provides a method for exchanging a dual wafer stage of a lithography machine, characterized in that the exchange method is carried out as follows: a) when the two wafer stages exchange positions, firstly, the first main driving unit drives the first Y direction guide And the first wafer stage rotates clockwise in the plane of the base, and the second main driving unit drives the second Y-direction guide and the second wafer stage to rotate clockwise in the plane of the base, and The first wafer stage auxiliary driving unit drives the first wafer stage to move along the first Y-direction rail toward the first main driving unit, and the second wafer stage auxiliary driving unit drives the second wafer stage to face along the second Y-direction rail. The second main driving unit moves in the direction; b) when the two Y-direction guides rotate to move in the X direction without mutual interference, the first main driving unit drives the first Y-direction guide rail and the first silicon wafer stage to move in the negative X direction. At the same time, the second main driving unit drives the second Y-direction guide rail and the second silicon wafer stage to move in the positive X direction, and the first single-degree-of-freedom auxiliary driving unit moves in the X negative direction, and the third single-degree-of-freedom auxiliary driving unit moves along the X direction. Directional movement c) When the two Y-direction guides are changed from the opposite direction to the reverse movement, the two Y-direction guides drive the wafer stage to rotate in the opposite direction, and the first wafer stage auxiliary drive unit drives the first wafer stage along the first Y The direction guide rail moves away from the direction of the first main driving unit, and the second wafer stage auxiliary driving unit drives the second wafer stage to move along the second Y direction guide rail away from the second main driving unit; meanwhile, the second single degree of freedom auxiliary driving unit Moving to and corresponding to the corresponding position of the second Y-direction rail, and driving the second wafer stage to the exposure station together with the second main driving unit and the second auxiliary driving unit, and the fourth single-degree-of-freedom auxiliary driving unit is moved And corresponding to the first Y-direction rail and docking with the first main driving unit and the first auxiliary driving unit to drive the first wafer stage to the pre-processing station, thus completing the first wafer stage Exchange with the position of the second wafer stage and proceed to the next cycle.

The invention provides a lithography machine dual silicon wafer exchange system, which comprises a first wafer stage running at an exposure station, a second wafer stage running at a pretreatment station, a base station, a first X Direction linear guide, second X direction linear guide, first single degree of freedom auxiliary drive unit, second single degree of freedom auxiliary drive unit, third single degree of freedom auxiliary drive unit, fourth single degree of freedom auxiliary drive unit, first Y a direction guide rail, a second Y-direction guide rail, a first wafer stage auxiliary driving unit, and a second wafer stage auxiliary driving unit, the first Y-direction rail passes through the first wafer stage, and the second Y-direction rail passes through the second silicon a stage; the system further comprising: a first main driving unit disposed on the first X-direction linear guide; and a second main driving unit disposed on the second X-direction linear guide; the first main The driving unit and the second main driving unit have a degree of freedom of movement in the X direction and a degree of freedom of rotation perpendicular to the plane of the base; the first main driving unit is coupled to one end of the first Y-direction rail, the first Y direction The other end of the rail and the third single The second auxiliary driving unit is connected to one end of the second Y-direction guide rail, and the other end of the guide rail is coupled to the first single-degree-of-freedom auxiliary driving unit or the first The two-degree-of-freedom auxiliary driving unit is docked; the Y-direction guide rail and the single-degree-of-freedom auxiliary driving unit adopt a separate structure, and are disconnected when the two wafer table positions are exchanged.

A lithography machine dual silicon wafer exchange system according to the present invention is characterized in that: the first main driving unit and the second main driving unit are driven by a main driving unit linear motor mover, a torque motor and a vacuum preload The air bearing is composed of a stepping motor, or the linear motor is replaced by a stepping motor, and the vacuum preloaded air bearing is replaced by a permanent magnet preloaded air floating shaft. A ball guide or an air bearing is mounted between the top of the first main drive unit and the first X-direction guide rail, and between the top of the second main drive unit and the second X-direction guide rail as a guide support; The bottom surface of the first main driving unit and the second main driving unit in contact with the base is equipped with a permanent magnet preloaded air bearing.

A lithography machine dual silicon wafer exchange system according to the present invention is characterized in that: the first main driving unit, the second main driving unit, the first single degree of freedom auxiliary driving unit, and the second single The linearity motor of the degree of freedom auxiliary drive unit, the third single degree of freedom auxiliary drive unit, the fourth single degree of freedom auxiliary drive unit, the first wafer stage auxiliary drive unit, and the second wafer stage auxiliary drive unit are respectively mounted for position Feedback linear grating.

The first single degree of freedom auxiliary driving unit, the second single degree of freedom auxiliary driving unit, the third single degree of freedom auxiliary driving unit and the fourth single degree of freedom auxiliary driving unit of the present invention are all equipped with linear motor movers at the bottom. The side contacting the abutment is equipped with a vacuum preloaded air bearing, and the bottom surface in contact with the abutment is equipped with a permanent magnet preloaded air bearing.

A lithography machine dual silicon wafer exchange system according to the present invention further comprises a dual frequency laser interferometer for moving position feedback of the silicon wafer stage.

Beneficial effect

Compared with the prior art, the invention has the following outstanding advantages: one is that the silicon wafer stage of the system is driven by the centroid; the other is that the four auxiliary driving units are single degrees of freedom, which simplifies the control system structure and reduces the system zero. The installation accuracy requirements of the components; third, the exchange surface does not use air bearing exchange, reducing the dimensional consistency requirements; Fourth, further shorten the system's dual silicon wafer exchange time, improve system efficiency and space utilization.

DRAWINGS

Figure 1 is a schematic diagram of the working principle of the lithography machine.

2 is a state diagram of a wafer stage dual stage exchange system of a lithography machine of the present invention and before exchange.

Figure 3 shows the structure of the drive unit on both sides of the wafer stage.

Figure 4 shows the structure of the wafer stage and the Y-direction guide.

Figure 5 shows the connection between the wafer stage, the Y-direction guide and the single-degree-of-freedom auxiliary drive unit.

Figure 6 shows the structure of a two degree of freedom main drive unit.

Figure 7 shows the structure of a single degree of freedom auxiliary drive unit.

Figure 8 shows the exchange process for two wafer stages.

In the figure: 1 - first single degree of freedom auxiliary drive unit; 2 - first X direction guide; 3 - first wafer stage; 4 - first Y direction guide; 5 - base; 6 - second X direction guide ; 7 - second single degree of freedom auxiliary drive unit; 8 - second wafer stage; 9 - second Y direction guide; 10 - first main drive unit; 11 - first wafer stage auxiliary drive unit; Two-silicon wafer auxiliary driving unit; 13-second main driving unit; 14-torque motor; 15-third single-degree-of-freedom auxiliary driving unit; 16-fourth single-degree-of-freedom auxiliary driving unit; 17-single-degree-of-freedom driving unit Linear motor mover; 18—main drive unit linear motor mover; 19-vacuum preloaded air bearing; 20—permanent magnet preloaded air bearing; 21—Y direction guide linear motor stator magnet; 22—silicon wafer stage Bottom air bearing; 23-Y direction guide air bearing; 24 - closed preloaded air bearing; 25a - Y direction rail butt side; 25b - single degree of freedom auxiliary drive unit butt side; 26 - light source; Stencil; 28-lens system; 29-silicon wafer.

Embodiments of the invention

The structure, principle and working process of the present invention will be further described below with reference to the accompanying drawings.

2 is a schematic structural view of a dual silicon wafer exchange system of a lithography machine according to the present invention, the system includes a first wafer stage 3 running at an exposure station, and a second wafer stage 8 running at a pretreatment station, a first X-direction linear guide 2, a second X-direction linear guide 6, a first single-degree-of-freedom auxiliary drive unit 1, a second single-degree-of-freedom auxiliary drive unit 7, a third single-degree-of-freedom auxiliary drive unit 15, and a fourth single free The auxiliary driving unit 16, the first Y-direction guide rail 4, the second Y-direction guide rail 9, the first wafer stage auxiliary driving unit 11, the second wafer stage auxiliary driving unit 12, the first main driving unit 10, and the second main The driving unit 13 and the base 5, the long side of the base is the X direction, and the short side is the Y direction; the first main driving unit 10 and the second main driving unit 13 have the freedom of movement in the X direction and are perpendicular to Rotational freedom of the abutment plane, the first main drive unit is coupled to one end of the first Y-direction guide rail, the other end of the first Y-direction guide rail and the third single-degree-of-freedom auxiliary drive unit or the fourth single-degree-of-freedom auxiliary drive unit Docking, the second main drive unit and the second Y-direction guide 9 One end of the second Y-direction rail rail is connected to the first single-degree-of-freedom auxiliary driving unit 1 or the second single-degree-of-freedom auxiliary driving unit 7; the Y-direction rail is driven by the main driving unit or Under the common driving of the single-degree-of-freedom auxiliary driving unit, the movement of the wafer stage in the X direction can be realized, and the Y-direction guide rail and the single-degree-of-freedom auxiliary driving unit adopt a separate structure, and are disconnected when the two wafer stage positions are exchanged.

The first main driving unit 10, the third single degree of freedom auxiliary driving unit 15 and the fourth single degree of freedom auxiliary driving unit 16 share the first Y direction linear guide 4; the second main driving unit 13, the first single degree of freedom auxiliary driving unit 1 and the second single-degree-of-freedom auxiliary driving unit 7 share the second Y-direction linear guide 9; the first Y-direction guide 4 passes through the first wafer stage 3, one end of the first Y-direction guide 9 and the first main driving unit 10 Coupling, the other end is coupled with the third single-degree-of-freedom auxiliary driving unit 15 , and the first driving unit 10 and the third single-degree-of-freedom auxiliary driving unit 15 are driven together to realize the movement of the first wafer stage in the X direction; The first Y-direction guide rail 4 can realize a rotary motion perpendicular to the plane of the base plate under the driving of the first main drive unit 10; the second Y-direction guide rail 9 passes through the second wafer stage 8, and one end of the second Y-direction guide rail The second main driving unit 13 is coupled, and the other end is connected to the first single-degree-of-freedom auxiliary driving unit 1. When the second main driving unit 13 and the first single-degree-of-freedom auxiliary driving unit 1 are driven together, the second silicon wafer stage can be realized. Move in the X direction.

3 and 4 show the structure and connection mode of the wafer stage, the X-direction guide rail, the Y-direction guide rail, the air bearing, the single-degree-of-freedom auxiliary drive unit, the main drive unit, and the first single-degree-of-freedom auxiliary drive unit 1, The bottoms of the two single-degree-of-freedom auxiliary driving unit 7, the third single-degree-of-freedom auxiliary driving unit 15, and the fourth single-degree-of-freedom auxiliary driving unit 16 are all equipped with a linear motor mover, and the bottom surface in contact with the base is equipped with a permanent magnet pre-prepared a carrier air bearing or a vacuum preload air bearing, the stator is mounted on the base 5, and the third single degree of freedom auxiliary driving unit or the fourth single degree of freedom auxiliary driving unit is docked with the first Y direction rail 4, and A main driving unit 10 cooperates to jointly drive the first silicon wafer table to move in the X direction; the coupling manner of the X direction guide rail and the main driving unit can be realized by using a ball guide or an air bearing guide, a magnetic force or a vacuum preload; The connection mode of the guide rail and the main drive unit is realized by means of screw fixing, and the other end is connected with a single-degree-of-freedom auxiliary driving unit, and electromagnetic or vacuum adsorption is adopted to achieve precise docking; Y-direction The rail is driven by a torque motor, a linear motor or a stepper motor to achieve rotational motion and movement in the X direction.

Figure 4 shows the coupling structure of the wafer stage and the Y-direction guide. The bottom of the first wafer stage 3 is provided with a vacuum preloaded air bearing, the upper surface of the base is a guiding surface, the first Y direction rail 4 penetrates from the inside of the first wafer stage 3, and the first Y direction rail 4 is mounted with Y. The directional guide linear motor stator magnet, the coil is mounted as a linear motor mover on the wafer stage; the two inner vertical faces of the first wafer stage 3 are also equipped with a closed preload air bearing to constrain the first wafer stage 3 Move along the guide rail in the Y direction.

Figure 5 shows the coupling between the first Y-direction rail 4 and the single-degree-of-freedom auxiliary drive unit 15. The third single-degree-of-freedom auxiliary driving unit 15 is docked with the first Y-direction guide rail 4, and the joint surface can be accurately docked and detached by electromagnetic or vacuum adsorption to achieve position exchange of the wafer stage.

Figure 6 shows the structure of the first main drive unit. The first main driving unit 10 is equipped with a linear motor mover 18 and a torque motor 14, which has two degrees of freedom of translation and rotation, and is driven by a torque motor, a linear motor or a stepping motor, and can realize translation in the X direction. And rotating around the first main driving unit; the bottoms of the first main driving unit 10 and the second main driving unit 13 are respectively equipped with linear motor movers 18, and the bottom surface is equipped with a permanent magnet preloaded air bearing 20; A ball guide or an air bearing is used as a guide support between the Y-direction guide rail and the Y-direction guide rail.

Figure 7 shows the structure of a single degree of freedom auxiliary drive unit. The single-degree-of-freedom auxiliary drive unit and the main drive unit drive the wafer stage to move in the X direction. The single-degree-of-freedom auxiliary drive unit is equipped with a linear motor mover 17 at the bottom, and a vacuum preloaded air bearing 19 is mounted on the side. Both are equipped with permanent magnet preloaded air bearing.

The system of the present invention also includes a dual frequency laser interferometer for feedback of the position of the wafer stage. In addition, the first main driving unit 10, the second main driving unit 13, the first single degree of freedom auxiliary driving unit 1, the second single degree of freedom auxiliary driving unit 17, and the third single degree of freedom auxiliary driving unit 15, A linear grating for position feedback is mounted on each of the linear motors of the fourth single-degree-of-freedom auxiliary driving unit 16, the first wafer stage auxiliary driving unit 11, and the second wafer stage auxiliary driving unit 12.

Figure 8 shows the exchange process of the dual silicon wafer exchange system of the lithography machine of the present invention, which is carried out as follows:

a) The first wafer stage 3 and the second wafer stage 8 are in a position state before the exchange, and the third single-degree-of-freedom auxiliary driving unit 15 is docked with the first Y-direction guide 4 and is driven together with the first main drive unit 10. The first wafer stage 3 is in the exposure station; the first single degree of freedom auxiliary driving unit 1 is docked with the second Y direction rail 9 and drives the second wafer stage 8 together with the second main driving unit 13 in the pretreatment station. After the two wafer stages have completed the pre-processing and exposure processes, the system enters the dual-sink state.

b) First, the first Y-direction guide rail 4 is disengaged from the third single-degree-of-freedom auxiliary drive unit 15, and the first main drive unit 10 drives the first Y-direction guide rail 4 and drives the first wafer stage 3 to be compliant in the plane of the base station. Rotational movement in the hour hand direction while the second Y-direction guide 9 is disengaged from the first single-degree-of-freedom auxiliary drive unit 1, and the second main drive unit 13 drives the second Y-direction guide 9 and the second wafer stage 8 to be made in the plane of the base. Rotating motion in a clockwise direction, and the first wafer stage auxiliary driving unit 11 drives the first wafer stage 3 to move along the first Y-direction rail 4 toward the first main driving unit 10, and the second wafer stage auxiliary driving unit 12 drives The second wafer stage 8 moves along the second Y-direction guide rail 9 toward the second main driving unit 13, as shown in FIG. 7(a);

c) Next, when the two Y-direction guide rails rotate to move in the X direction without mutual interference, the first main drive unit 10 drives the first Y-direction guide rail 4 and the first wafer stage 3 to move in the negative X direction, and at the same time The main driving unit 13 drives the second Y-direction guide 9 and the second wafer stage 8 to move in the positive X direction, and the first single-degree-of-freedom auxiliary driving unit 1 moves in the X negative direction, and the third single-degree-of-freedom auxiliary driving unit 15 X moves in the positive direction and moves to the edge to stop, as shown in Figure 7(b);

d) Then, when the two Y-direction guides are changed from the opposite direction to the reverse movement, the two Y-direction guides drive the respective wafer stages to rotate in the counterclockwise direction, and the first auxiliary drive unit 11 drives the first wafer stage 3 Moving along the first Y-direction guide rail 4 away from the first main drive unit 10, the second auxiliary drive unit 12 drives the second wafer stage 8 to move along the second Y-direction guide rail 9 away from the second main drive unit 13, as shown in FIG. (c);

e) Finally, when the two Y-direction guide rails are perpendicular to the X direction, the second single-degree-of-freedom auxiliary drive unit 7 moves to the corresponding position of the second Y-direction guide rail 9 and abuts it, and the second main drive unit 13 and the The two wafer stage auxiliary driving unit 12 drives the second silicon wafer stage 8 to the exposure station, and the fourth single degree of freedom auxiliary driving unit 16 moves to the corresponding position of the first Y direction rail 4 and interfaces with the same. A main driving unit 10 and the first silicon wafer auxiliary driving unit 11 jointly drive the first silicon wafer stage 3 to the pre-processing station, as shown in FIG. 7(d), and thus the first silicon wafer stage 3 and the second silicon The stage 8 completes the position exchange and starts the next cycle.

Claims

1. A lithography machine dual silicon wafer exchange method, characterized in that the method is carried out as follows:

a) When the two wafer stages are exchanged, first, the first main driving unit (10) drives the first Y-direction rail (4) and the first wafer stage (3) to make a clockwise direction in the plane of the base (5). Rotating motion while the second main driving unit (13) drives the second Y-direction rail (9) and the second wafer stage (8) to also perform clockwise rotational movement in the plane of the base (5), and the first silicon The stage auxiliary driving unit (11) drives the first wafer stage (3) to move along the first Y-direction rail (4) toward the first main driving unit (10), and the second wafer stage auxiliary driving unit (12) drives The second wafer stage (8) moves along the second Y-direction rail (9) toward the second main driving unit (13);

b) when the two Y-direction guide rails rotate to move in the X direction without mutual interference, the first main drive unit (10) drives the first Y-direction guide rail (4) and the first wafer stage (3) to move in the X negative direction. At the same time, the second main driving unit (13) drives the second Y-direction guide rail (9) and the second silicon wafer stage (8) to move in the positive X direction, and the first single-degree-of-freedom auxiliary driving unit (1) is along the X negative direction. Movement, the third single degree of freedom auxiliary drive unit (15) moves in the positive X direction;

c) When the two Y-direction guides are changed from the opposite direction to the reverse movement, the two Y-direction guides drive the wafer stage to rotate in the opposite direction, and the first wafer stage auxiliary drive unit (11) drives the first wafer stage ( 3) moving along the first Y-direction guide rail (4) away from the first main drive unit (10), and the second wafer stage auxiliary drive unit (12) driving the second wafer stage (8) along the second Y-direction guide rail ( 9) moving away from the second main drive unit (13); at the same time, the second single-degree-of-freedom auxiliary drive unit (7) moves to and corresponds to the corresponding position of the second Y-direction guide rail (9), and the second main The driving unit (13) and the second auxiliary driving unit (12) jointly drive the second wafer stage (8) to the exposure station, and the fourth single degree of freedom auxiliary driving unit (16) moves to the first Y direction rail (4) Corresponding position and docking with the first main drive unit (10) and the first auxiliary drive unit (11) to drive the first wafer stage (3) to the pre-processing station, thus completing the The position of a silicon wafer stage (3) and the second silicon wafer stage (8) are exchanged, and the next step is entered. Ring.

2. A lithography double silicon wafer exchange system using the method of claim 1 The system comprises a first wafer stage (3) running at an exposure station, a second wafer stage (8) running at a pretreatment station, a base (5), and a first X-direction linear guide (2) a second X-direction linear guide (6), a first single-degree-of-freedom auxiliary drive unit (1), a second single-degree-of-freedom auxiliary drive unit (7), a third single-degree-of-freedom auxiliary drive unit (15), and a fourth single Degree of freedom auxiliary drive unit (16), first Y-direction guide rail (4), second Y-direction guide rail (9), first wafer stage auxiliary drive unit (11) and second wafer stage auxiliary drive unit (12) a first Y-direction guide rail (4) passing through the first wafer stage (3), and a second Y-direction guide rail (9) passing through the second wafer stage (8); characterized in that: the system further comprises a first main driving unit (10) on the first X-direction linear guide (2) and a second main driving unit (13) disposed on the second X-direction linear guide (6); the first main driving unit (10) and the second main drive unit (13) have a degree of freedom of movement in the X direction and a degree of freedom of rotation perpendicular to the plane of the base The first main driving unit (10) is coupled to one end of the first Y-direction rail (4), the other end of the first Y-direction rail (4) and the third single-degree-of-freedom auxiliary driving unit (15) or the The four-degree-of-freedom auxiliary driving unit (16) is docked; the second main driving unit (13) is coupled to one end of the second Y-direction rail (9), and the other end of the rail and the first single-degree-of-freedom auxiliary driving unit (1) or the second single-degree-of-freedom auxiliary driving unit (7) is docked; the Y-direction guide rail and the single-degree-of-freedom auxiliary driving unit adopt a separate structure, and are disconnected when the two wafer table positions are exchanged.

3. A lithography double wafer stage exchange system according to claim 2, wherein said first main driving unit (10) and said second main driving unit (13) are linearly driven by a main driving unit Sub (18), torque motor (14) and vacuum preloaded air bearing (20), or replaced by a stepper motor, the permanent magnet preloaded air floating shaft replaces the vacuum preload Air bearing.

4. A lithography double wafer stage exchange system according to claim 2, wherein: between the top of the first main driving unit (10) and the first X-direction rail (2), the second A ball guide or an air bearing is mounted as a guide support between the top of the main drive unit (13) and the second X-direction guide rail (6); the first main drive unit (10) and the second main drive unit ( 13) The bottom surface in contact with the abutment (5) is equipped with a permanent magnet preloaded air bearing.

5. A lithography dual silicon wafer exchange system according to claim 2, wherein said first main driving unit (10), said second main driving unit (13), and said first single degree of freedom Auxiliary drive unit (1), second single degree of freedom auxiliary drive unit (7), third single degree of freedom auxiliary drive unit (15), fourth single degree of freedom auxiliary drive unit (16), first wafer stage auxiliary drive A linear grating for position feedback is mounted on the linear motor of the unit (11) and the second wafer stage auxiliary drive unit (12), respectively.

6. According to the claims 2. The lithography double wafer stage exchange system of 2, 3, 4 or 5, characterized in that: the first single degree of freedom auxiliary driving unit (1) and the second single degree of freedom auxiliary driving unit ( 7), the third single-degree-of-freedom auxiliary driving unit (15) and the fourth single-degree-of-freedom auxiliary driving unit (16) are equipped with a linear motor mover (17) at the bottom, and the side contacting the base (5) is mounted There is a vacuum preloaded air bearing (19), and the bottom surface in contact with the base (5) is equipped with a permanent magnet preloaded air bearing (20).

7. A lithography dual silicon wafer exchange system according to claim 6, wherein said lithography double wafer stage change system further comprises a dual frequency laser for feeding position feedback of the silicon wafer stage. Interferometer.