CN201364460Y - Double wafer stage exchanging device of photo-etching machine - Google Patents

Abstract

The invention discloses a dual-table exchanging device for silicon wafers of a lithography machine, which comprises a base table, two pretreatment stations and one exposure station. The base platform is provided with a silicon wafer stage running on a pretreatment station and a silicon wafer stage running on an exposure station. A linear motor stator and two single-degree-of-freedom drive units moving in the X direction are respectively arranged on the long sides of the abutment to form a linear motor. A guide rail in the Y direction passes through the wafer stage, and the guide rails in the Y direction are connected to the abutment respectively. The single-degree-of-freedom drive units moving in the X direction on both sides are connected to jointly drive the silicon wafer stage to move in the X-Y plane; the utility model avoids the extremely high precision of guide rail docking caused by only the silicon wafer stage participating in the exchange, and Defects such as the need to add docking auxiliary devices greatly simplify the system structure. Second, the system’s dual-unit exchange is realized by four identical single-degree-of-freedom drive units, which greatly reduces the complexity of the system.

Description

A dual-stage exchanging device for a silicon wafer stage of a lithography machine

technical field

The utility model relates to a dual-table exchanging device for silicon chip tables of a lithography machine. The device is applied to a semiconductor lithography machine and belongs to the technical field of semiconductor manufacturing equipment.

Background technique

In the production process of integrated circuit chips, the exposure transfer (photolithography) of the design pattern of the chip on the photoresist on the surface of the silicon wafer is one of the most important processes. The equipment used in this process is called a photolithography machine (exposure machine). The resolution and exposure efficiency of the lithography machine greatly affect the characteristic line width (resolution) and productivity of the integrated circuit chip. As the key system of the lithography machine, the motion accuracy and work efficiency of the silicon wafer ultra-precision motion positioning system (hereinafter referred to as the wafer stage) 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 45 passes through the reticle 47 and the lens system 49 to image a part of the pattern on the reticle on a chip of the silicon wafer 50 . The reticle and the silicon wafer move synchronously in reverse at a certain speed ratio, and finally image all the patterns on the reticle on a specific chip (Chip) of the silicon wafer.

The basic function of the movement positioning system of the silicon wafer stage is to carry the silicon wafer and move according to the set speed and direction during the exposure process, so as to realize the precise transfer of the mask pattern to each area on the silicon wafer. Since the line width of the chip is very small (currently the minimum line width has reached 45nm), in order to ensure the overlay accuracy and resolution of lithography, the silicon wafer stage is required to have extremely high motion positioning accuracy; since the movement speed of the silicon wafer stage is within It greatly affects the productivity of lithography, and from the perspective of improving productivity, it also requires the movement speed of the silicon wafer table to be continuously improved.

In the traditional wafer stage, as described in patent EP 0729073 and patent US 5996437, there is only one wafer motion positioning unit in the lithography machine, that is, a wafer stage. The preparatory work such as leveling and focusing must be done on it. These tasks take a long time, especially for alignment. Due to the requirement of extremely high-precision low-speed scanning (typical alignment scanning speed is 1mm/s), so It takes a long time. It is very difficult to reduce their working hours. In this way, in order to improve the production efficiency of the lithography machine, it is necessary to continuously increase the moving speed of the stepping of the silicon wafer stage and the exposure scanning. The increase in speed will inevitably lead to the deterioration of the dynamic performance of the system, and a large number of technical measures need to be taken to ensure and improve the motion accuracy of the silicon wafer stage, and the price to be paid to maintain the existing accuracy or achieve higher accuracy will be greatly increased.

The structure described in patent W098/40791 (publication date: 1998.9.17; country: the Netherlands) adopts a double wafer stage structure, and transfers exposure preparations such as loading and unloading, pre-alignment, and alignment to the second wafer stage on, and move independently with the exposure wafer stage at the same time. On the premise of not increasing the movement speed of the wafer stage, a large amount of preparation work for the exposure wafer stage is shared by the second wafer stage, thus greatly shortening the working time of each wafer on the exposure wafer stage and greatly improving production efficiency. However, the main disadvantage of this system is the non-centroid driving problem of the wafer stage system.

The applicant's invention patent "a dual-stage exchange system for lithography machine silicon wafers" (publication number: CN101101454) disclosed in 2007 discloses a dual-stage exchange system for lithography machines, which has a simple structure and space utilization. The advantages of high efficiency improve the exposure efficiency of the lithography machine. However, there are still some problems in this double wafer stage system. First, the air bearing needs to exchange the guide surface when the wafer stage is exchanged, resulting in extremely high precision requirements for the size consistency of the wafer stage, and the processing and assembly of parts. The accuracy is required to be above the micron level; the second is that it is difficult to install sensors for detecting mutual positions between the guide rails involved in the exchange, and collisions may occur between the upper linear guide rails; the third is the non-centroid drive of the silicon wafer stage system.

Utility model content

Aiming at the deficiencies and defects of the prior art, the purpose of this utility model is to provide a double-swap exchange system for photolithography machines to overcome the non-centroid drive, complex structure and extremely demanding The disadvantages of high rail butt joint accuracy make it have the advantages of simple structure, high space utilization and no need for docking auxiliary devices, thereby improving the exposure efficiency of the lithography machine.

The technical scheme of the utility model is as follows:

A dual-stage exchanging device for silicon wafer stages of a lithography machine, the device includes a base stage (1), two pretreatment stations (2), (4), and an exposure station (3);

The base platform (1) is provided with a silicon wafer stage (16) operating at the pretreatment station (2) and a silicon wafer stage (17) operating at the exposure station (3);

A linear motor magnetic steel stator (9) and (10) are respectively arranged in the X direction on the long side edges on both sides of the abutment (1), and the first single-degree-of-freedom drive unit (5) moved by the X direction, the second The single-degree-of-freedom drive unit (6) shares the linear motor stator magnet (9), the third single-degree-of-freedom drive unit (7) moving in the X direction, and the fourth single-degree-of-freedom drive unit (8) share the linear motor stator Magnetic steel (10);

The guide rails (18) in the Y direction of the long side edges on both sides pass through the silicon wafer stage (16) and drive the silicon wafer stage (16) to move along the Y direction, and the guide rails (18) in the Y direction are respectively connected with the first one moving in the X direction. A single-degree-of-freedom driving unit (5) is connected with a third single-degree-of-freedom driving unit (7) to jointly drive the silicon wafer stage (16) to move in the X-Y plane;

The guide rails (19) in the Y direction of the long side edges on both sides pass through the silicon wafer stage (17) and drive the silicon wafer stage (17) to move along the Y direction, and the guide rails (19) in the Y direction are respectively connected with the first one moving in the X direction. The second single-degree-of-freedom driving unit (6) is connected with the fourth single-degree-of-freedom driving unit (8) to jointly drive the silicon wafer stage (17) to move in the X-Y plane;

The dual-frequency laser interferometers (11) and (15) for measuring the displacement in the X direction are respectively arranged around the base station (1), and the dual-frequency laser interferometers (12), (13) and (15) for measuring the displacement in the Y direction 14).

The technical feature of the utility model is that: linear gratings are installed on the upper linear guide rail and the lower linear guide rail, which are used for position feedback of the two-degree-of-freedom drive unit.

Another technical feature of the utility model is: the system also includes a linear grating for detecting the motion position of the linear motor and a dual-frequency laser interferometer for the feedback of the motion position of the silicon wafer stage.

Compared with the prior art, the utility model has the following outstanding advantages: one is that the system has two pretreatment stations, including the wafer table, two connected single-degree-of-freedom drive units and the Y-direction guide rail The exchange of the overall structure avoids the extremely high precision of guide rail docking caused by only exchanging the silicon wafer table, and the need to increase the docking auxiliary device and other defects, which greatly simplifies the system structure. The second is that the system uses four The exact same single-degree-of-freedom drive unit is realized, and the complexity of the system is greatly reduced.

Description of drawings

FIG. 1 is a structural diagram of a double-swapping system for silicon wafer tables of a lithography machine provided by the present invention.

Fig. 2a is the switching process 1 of the double-swapping system for silicon wafer tables of a lithography machine provided by the present invention.

Fig. 2b is the switching process 2 of the double-swapping system for the silicon wafer stage of the lithography machine provided by the present invention.

In the picture:

1: Abutment

2: Pretreatment station

3: Exposure station

4: Pretreatment station

5: Single degree of freedom drive unit

6: Single degree of freedom drive unit

7: Single degree of freedom drive unit

8: Single degree of freedom drive unit

9: Linear motor stator magnet

10: Linear motor stator magnet

11: Dual frequency laser interferometer

12: Dual frequency laser interferometer

13: Dual frequency laser interferometer

14: Dual frequency laser interferometer

15: Dual frequency laser interferometer

16: Wafer table

17: Wafer table

18: Y direction guide rail

19: Y direction guide rail

Detailed ways

FIG. 1 shows a schematic diagram of the structure of a double-swap exchange system for a lithography machine. The system includes a base 1 , two pretreatment stations 2 and 4 , and an exposure station 3 . As shown in FIG. 1 , the wafer stage 16 operates at the pretreatment station 2 , and the wafer stage 17 operates at the exposure station 3 . A linear motor magnetic steel stator 9 and 10 are respectively arranged on the long side edges on both sides, that is, the X direction, and the single-degree-of-freedom drive units 5 and 6 that move in the X direction share the linear motor stator 9. Similarly, the single-degree-of-freedom drive units that move in the X direction Degree drive units 7 and 8 share the linear motor stator 10; the guide rail 18 in the Y direction passes through the wafer stage 16 and drives the wafer stage 16 to move in the Y direction, and the guide rail 18 in the Y direction is driven by a single degree of freedom that moves in the X direction respectively. Units 5 and 7 are connected to jointly drive the wafer stage 16 to move in the X-Y plane. Similarly, the guide rail 19 in the Y direction passes through the wafer stage 17 and drives the wafer stage 17 to move in the Y direction, and the guide rails 19 in the Y direction are respectively connected to The single-degree-of-freedom drive units 6 and 8 that move in the X direction are connected to jointly drive the wafer stage 17 to move in the X-Y plane; dual-frequency laser interferometers 11 and 15 that measure the displacement in the X direction are arranged around the base, and measure the displacement in the Y direction. Displaced dual frequency laser interferometers 12, 13 and 14.

The bottom of the wafer stage is equipped with a vacuum preloaded air bearing, the upper surface of the base 1 is a guiding surface, the Y direction guide rail runs through the wafer stage, the Y direction guide rail is installed with a linear motor stator magnetic steel, and the coil is used as a linear motor mover Installed on the wafer stage, closed preloaded air bearings are installed on the two inner vertical surfaces of the wafer stage to constrain the relative movement of the guide rail in the Y direction and the wafer stage along the Y direction.

The bottoms of the single-degree-of-freedom drive units 5, 6, 7 and 8 are equipped with linear motor coil movers and vacuum preloaded air bearings, and the linear motor magnetic steel stators 9 and 10 are respectively installed on both sides of the long side of the base 1. The single-degree-of-freedom drive units 5 and 7 are connected to the Y-direction guide rail 18 to drive the wafer stage 16 to move along the X-Y plane. The single-degree-of-freedom drive units 6 and 8 are connected with the Y-direction guide rail 19 to drive the wafer stage 17 to move along the X-Y plane.

FIG. 2 shows the exchange process of the silicon wafer stage double exchange system of the lithography machine provided by the present invention. In the solution of the present invention, a pretreatment station is respectively provided on both sides of the base 1, which facilitates the exchange. As shown in Figure 2(a), after the wafer stage 17 running in the exposure station 3 completes the exposure work, the wafer stage 17 is jointly driven along the X direction movement to the right pretreatment station 4, and at the same time, the wafer stage 16 waiting at the left pretreatment station 2 moves in the X direction under the cooperation of the single-degree-of-freedom drive units 6 and 8 and the Y-direction guide rail Go to middle exposure station 3 and start exposure work.

As shown in Figure 2(b), when the wafer stage 16 finishes the exposure work, it moves back to the left pretreatment station 2 along the X direction for pretreatment such as loading and unloading. The wafer stage 17 of 4 moves to the left along the X direction to the exposure station 3, and enters the next cycle.

Claims (3)

1. photo-etching machine silicon chip platform double-platform switch, this device contains base station (1), two pre-service stations (2), (4), exposure station (3);

The described silicon chip platform (16) that runs on pre-service station (2), the silicon chip platform (17) that runs on exposure station (3) of on base station (1), being provided with;

It is described that edge, long limit directions X is respectively arranged with straight line magnetic steel of motor stator (9) and (10) in base station (1) both sides, the first single-degree-of-freedom driver element (5) by the directions X motion, the second shared linear motor stator electric magnet steel of single-degree-of-freedom driver element (6) (9), described the 3rd single-degree-of-freedom driver element (7) by the directions X motion, the 4th shared linear motor stator electric magnet steel of single-degree-of-freedom driver element (8) (10);

The guide rail (18) of edge, long limit, described both sides Y direction passes silicon chip platform (16) and drives silicon chip platform (16) and moves along the Y direction, and the guide rail of Y direction (18) connects with the first single-degree-of-freedom driver element (5) and the 3rd single-degree-of-freedom driver element (7) that directions X moves respectively, drives silicon chip platform (16) jointly and moves at X-Y plane;

The guide rail (19) of edge, long limit, described both sides Y direction passes silicon chip platform (17) and drives silicon chip platform (17) and moves along the Y direction, and the guide rail of Y direction (19) connects with the second single-degree-of-freedom driver element (6) and the 4th single-degree-of-freedom driver element (8) that directions X moves respectively, drives silicon chip platform (17) jointly and moves at X-Y plane;

Describedly be furnished with two-frequency laser interferometer (11) and (15) of the displacement of measured X direction on every side respectively, in two-frequency laser interferometer (12), (13) and (14) of measuring the displacement of Y direction at base station (1).

2. according to the described a kind of photo-etching machine silicon chip platform double-platform switch of claim 1, it is characterized in that: described bottom at single-degree-of-freedom driver element (5), single-degree-of-freedom driver element (6), single-degree-of-freedom driver element (7) and single-degree-of-freedom driver element (8) is equipped with linear motor coil mover and vacuum preload air-bearing respectively, and described linear electric motors magnet steel stator (9) and (10) are installed in both sides, the long limit of base station (1) respectively.

3. according to the described a kind of photo-etching machine silicon slice bench double-bench switching system of claim 1, it is characterized in that: this system also comprises the two-frequency laser interferometer that is used for silicon chip platform movement position feedback.

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