CN105487343A - Plane-grating-measurement-based dynamic-magnetic-steel magnetic levitation dual-stage vector arc switching method and device - Google Patents

Abstract

The method and device for measuring moving magnet steel maglev double workpiece table vector arc transfer based on plane grating belongs to the technology of semiconductor manufacturing equipment. The workpiece table drive device, two workpiece tables work between the measurement position and the exposure position, the plane grating is used to measure the position of the workpiece table, and the passive compensation structure composed of a plane leaf spring and an electromagnetic damper is used to compensate the movement of the balance mass. The workpiece table is driven by a magnetic levitation planar motor. During the exchange process of the double workpiece table, the planar motor is used to drive the two workpiece tables to realize the single-beat arc rapid exchange; Problems such as many links, long stabilization time, and large cable disturbances can reduce the number of steps of changing channels, shorten the time of changing channels, and improve the productivity of the lithography machine.

Description

Method and device for moving magnetic steel maglev double workpiece table vector arc table change based on plane grating measurement

technical field

The invention belongs to the technical field of semiconductor manufacturing equipment, and mainly relates to a method and a device for a moving magnet steel maglev double workpiece table vector arc return conversion table based on plane grating measurement.

Background technique

Lithography machine is one of the important ultra-precision equipment in the manufacture of very large scale integrated circuits. As the key subsystem of the lithography machine, the workpiece table largely determines the resolution, overlay accuracy and productivity of the lithography machine.

Productivity is one of the main goals of lithography machine development. Under the condition of satisfying the resolution and overlay accuracy, improving the operating efficiency of the workpiece table and thus improving the productivity of the lithography machine is the development direction of the workpiece table technology. The most direct way to improve the operating efficiency of the workpiece table is to increase the motion acceleration and speed of the workpiece table, but in order to ensure the original accuracy, the speed and acceleration cannot be increased without limit. The initial workpiece table only had one silicon wafer carrier, and the lithography machine could only process one silicon wafer at a time. All processes were processed serially, and the production efficiency was low. For this reason, someone has proposed a double worktable technology, which is also the mainstream technical means to improve the production efficiency of lithography machines. The double worktable technology has two work stations for exposure and pretreatment and two workbenches on the workbench. The exposure and measurement adjustment can be processed in parallel, which greatly shortens the time and improves the production efficiency. The current representative product is the lithography machine based on the Twinscan technology, that is, the double-workpiece technology of ASML company in the Netherlands.

Improving the operating efficiency of the double workpiece table is one of the development goals of the current lithography machine workpiece table technology. The double workpiece table technology involves the problem of switching the workpiece table between two stations, and the efficiency of table switching directly affects the operating efficiency of the workpiece table of the lithography machine, that is, the productivity of the lithography machine. How to reduce the interference of channel switching to other systems while shortening the channel switching time as much as possible has always been the focus of research. In the traditional double-table switching process, the workpiece table is linearly driven in the exposure and pretreatment processes. In the dual-stage patents US2001/0004105A1 and W098/40791, each workpiece table has two interchangeable and coordinated units to achieve double-stage The exchange of the workpiece table improves the productivity without increasing the movement speed of the workpiece table. However, due to the coupling connection between the workpiece table and the guide rail, the workpiece table and the drive unit will be separated temporarily during the table change process, which will affect the workpiece table. The positioning accuracy has a great influence. At the same time, the motion unit and guide rail are longer, and the motion mass is larger, which has adverse effects on the improvement of motion speed and acceleration. Chinese patent CN101609265 proposes a planar motor-driven multiple exchange system for wafer stages. The stator of the planar motor is arranged on the top of the base stage, and the mover is arranged at the bottom of the wafer stage. Compared with the linear motor drive, there is no separation between the workpiece stage and the drive unit. Separation; Chinese patent CN101694560 proposes a dual-table exchange system driven by an air-supported permanent magnet planar motor. The workpiece table is driven by a planar motor and supported by air flotation, which avoids the separation of the drive unit and the workpiece table during the aforementioned table-changing process The problem is that the running resistance of the workpiece table is reduced, the driving current of the planar motor is reduced, and the problem of heat dissipation is reduced.

The above-mentioned patent adopts a straight-line table-changing scheme when changing tables, and the back-turning table-changing scheme has unique advantages over the straight-line table-changing scheme, so a double-workpiece table technology using a back-turning table appears. Chinese patent CN101071275 adopts the method of rotating the whole abutment to realize the transposition of the double workpiece table, which simplifies the system structure, and at the same time, the movement of the two workpiece tables has no overlapping area, avoiding the potential safety hazard of collision. However, there are problems such as large moment of inertia, difficulty in precise positioning of high-power rotary motors, and high heat generation that cause system temperature rise by rotating the entire base to achieve workpiece table transposition. At the same time, the radius of rotation is large, which significantly increases the main structure of the lithography machine. Chinese patent CN102495528 adopts a rotary transfer table in the center of the abutment to complete the exchange of double workpiece tables. The table change is divided into three beats, which improves the efficiency of the table change. However, the structure of the rotary transfer table is complicated and the rotary positioning accuracy is low.

The position measurement accuracy of the workpiece table directly affects the positioning accuracy of the workpiece table of the lithography machine, which in turn affects the minimum line width of the lithography machine. The workpiece table moves at a high speed, and the measurement scheme must meet the high-speed measurement and precision requirements. In US patents US6498350B2 and US20100279232A1, multiple laser interferometers are used to measure the position of a workpiece table. The laser interferometer has high measurement accuracy, The working distance is long, but the measurement optical path is too long, it is very sensitive to errors caused by humidity and air turbulence, and the cost is high.

Contents of the invention

Aiming at the deficiencies of the above-mentioned prior art, the present invention proposes a method and device for moving magnetic steel maglev double workpiece table vector arc return conversion table based on plane grating measurement, so as to achieve single-beat rapid arc change of workpiece table and reduce The purpose of changing the stage, shortening the stage changing time, and effectively improving the productivity of the lithography machine.

The purpose of the present invention is achieved in the following way: a method for measuring moving magnet steel magnetic levitation double workpiece table vector arc transfer method based on plane grating, the method includes the following steps: in the initial working state, the first workpiece table at the measurement position is in pre-alignment state, the second workpiece stage at the exposure position is in the exposure state; the first step, after the pre-alignment of the first workpiece stage at the measurement position, it is driven by the moving magnet to move to the predetermined position A of the measurement position and change the stage, charging and waiting, and the second workpiece stage at the exposure position After the exposure, the workpiece table is driven by the moving magnetic steel to move to the predetermined position C of the exposure position; in the second step, the first workpiece table and the second workpiece table move counterclockwise along the circular arc track through the vector control of the plane motor. During the movement, the two The phase of each workpiece table does not change, and the moving position is measured by the plane grating. When the first workpiece table is driven by the moving magnet to move to the predetermined position of the exposure position C, and the second workpiece table is driven by the moving magnet to move to the predetermined position of the measurement position. At D, the stage change is completed, the first workpiece stage performs silicon wafer photolithography exposure at the exposure position, and the second workpiece stage performs silicon wafer loading and silicon wafer pre-alignment operations at the measurement position; the third step is to measure the second workpiece After the pre-alignment of the stage is completed, it is driven by the moving magnetic steel to move to the predetermined position A' of the measurement position and the stage is charged and waits. Step 1, the second workpiece table and the first workpiece table move clockwise along the circular arc track through the plane motor vector control, when the second workpiece table is driven by the moving magnetic steel to move to the predetermined position C of the exposure position, the first workpiece table is driven by the moving magnetic steel When the drive moves to the predetermined position D of the measurement position, the stage change is completed, the second workpiece stage at the exposure position enters the exposure state, and the first workpiece stage at the measurement position performs loading and unloading and pre-alignment operations. At this time, the system returns to the initial working state and is completed. A working cycle including two channel-changing operations is completed by wireless communication in the process of measurement, exposure and channel-changing.

A vector arc-changing device based on planar grating measurement of moving magnetic steel maglev double workpiece table, the device includes a support frame, a balance weight block, a first workpiece table, a second workpiece table, and a wireless charging transmitter. The balance weight The block is located above the support frame, the stator of the macro-moving planar motor is installed on the plane on the balance mass block, the first workpiece table and the second workpiece table are arranged above the stator of the macro-moving planar motor, and the first workpiece table and the second workpiece table It runs between the measurement position and the exposure position, and the measurement position plane grating and the exposure position plane grating are respectively installed on the upper plane of the first work table and the second work table; The compensation mechanism is connected with the balance mass. The planar leaf spring is composed of 1 pair of X-direction leaf springs, 1 pair of Y-direction leaf springs, 1 Z-direction leaf spring and 1 Rz flexible hinge. The electromagnetic damper is composed of The back plate, the lower back plate of the damper, the Y-direction permanent magnet array and the X-direction permanent magnet array, the copper plate and the stainless steel column are assembled. The permanent magnet array is installed between the upper and lower back plates of the damper, and a strong magnetic field is formed between the air gap. A copper plate is installed in the strong magnetic field of the air gap, and the copper plate is fixed on the support frame. The upper back plate of the damper is connected to the balance The mass block is fixed, and it can produce X, Y translation and Rz rotation relative to the upper and lower backplane copper plates; the first work table and the second work table are six-degree-of-freedom maglev micro-motion stages, and the six-degree-of-freedom maglev micro-motion The table is composed of Chuck, suction cup, micro motor, anti-collision frame, macro planar motor mover, planar grating reading head, leveling and focusing sensor, wireless charging receiver, wireless communication transceiver. The movable planar motor mover and the gravity compensator mover are integrated together. The suction cup is installed on the Chuck. Four planar grating reading heads and four leveling and focusing sensors are installed on the four corners of the Chuck. The Chuck is fixed on the micro On the moving motor, an anti-collision frame is installed around the micro-motor, and the mover of the macro-moving planar motor is installed under the anti-collision frame. It consists of a coil array arranged in a herringbone shape.

The present invention has the following innovations and outstanding advantages:

1) Propose the arc vector channel changing method, and design the arc vector channel changing device. The vector table change strategy is used to optimize the existing multi-beat linear table change of the double workpiece table into a single-beat fast table change, with fewer starts and stops and fewer stable links; at the same time, the arc trajectory planning is used to shorten the table change path, and the rotary impact is small , The stabilization time is short, and the real-time measurement system monitors the exchange process to ensure the macro/micro positioning accuracy during the channel change process, directly traceable to the laser wavelength, and finally realizes the high efficiency and high precision of the channel change. This is one of the innovation points and outstanding advantages of the present invention;

2) A work table exchange method without cable interference of wireless power supply and wireless communication is proposed, and a double work table device for wireless power supply and wireless communication is designed. Based on the maglev magnetic drive, the device adopts wireless power supply and wireless signal transmission methods to realize the wireless transmission and control of the power supply and communication signals of the two micro-tables, making the overall structure compact, and more importantly, eliminating the need for cables and signal lines The impact of cable disturbance on the positioning accuracy of the double worktable realizes wireless power supply, wireless communication data transmission and no cable constraints. This is the second of innovation and outstanding advantages of the present invention;

3) A driving method based on moving magnet steel maglev planar motor is proposed, and a corresponding vector planar motor device is designed. It adopts compound current drive to realize high-efficiency vector control, realizes the synthesis and decomposition of six-degree-of-freedom vector force, and has the characteristics of large motion range, high thrust density, good dynamic characteristics, high winding utilization rate, uniform temperature distribution, and small thermal deformation. It adopts moving magnetic steel drive, wireless communication data transmission, no cable binding, simple structure, high positioning accuracy, which is the third innovation point and outstanding advantage of the present invention;

4) A measurement method based on planar grating is proposed, and a corresponding planar grating measurement device is designed. Compared with the planar grating measurement system, the laser interferometer system meets the measurement requirements of the lithography system in terms of measurement speed. At the same time, due to its low measurement noise, the measurement accuracy is higher than that of the laser interferometer, especially avoiding the plane reflection on the chuck table. The manufacturing difficulty and high cost, quality, and risk of excessive inertia of the right-angle reflector of the mirror are the fourth innovation point and outstanding advantage of the present invention;

5) Propose a passive compensation method and an impulse balance method, and design a passive compensation mechanism and a balance mass mechanism based on a planar leaf spring and an electromagnetic damper in parallel. This mechanism can realize the X-direction, Y-direction, Z-direction and Rz motion compensation of the balance mass. Compared with the active compensation structure, it reduces the complexity of the mechanism and reduces the difficulty of control and implementation. This is the innovation and highlight of the present invention. The fifth advantage.

Description of drawings

Fig. 1 is a schematic diagram of a single-beat optimized planning arc fast channel change process.

Fig. 2 is a schematic diagram of the overall structure of the vector arc-changing device based on the planar grating measurement of the moving magnet steel maglev double workpiece table.

Figure 3 is a cross-sectional view of the dual work table system.

Fig. 4 is a schematic diagram of the assembly structure of the motion compensation mechanism and the balance mass.

Fig. 5 is a schematic diagram of the planar leaf spring structure.

Fig. 6 is a schematic diagram of the electromagnetic damping structure.

Fig. 7 is a schematic diagram of the magnetic steel arrangement of the electromagnetic damper.

Fig. 8 is a schematic structural diagram of a six-degree-of-freedom maglev micro-motion stage.

Fig. 9 is a schematic diagram of the integration mechanism of the micro-motion planar motor mover and the gravity compensator.

Fig. 10 is a schematic diagram of the arrangement of the magnetic rigid array of the macro-moving planar motor mover.

Fig. 11 is a schematic diagram of the arrangement of the stator coil array of the macro-motion planar motor.

Part number in the picture: 1-supporting frame; 2-balance mass system; 3-macro planar motor stator; 4a-first workpiece table; 4b-second workpiece table; 5a-measuring plane grating; 5b-exposure plane Grating; 11-measurement position; 12-exposure position; 13-parallel leaf spring; 14-electromagnetic damper; 21-back plate of damper; 22-copper plate; 23-stainless steel column; 24b-X-direction permanent magnet array; 25-damper lower back plate; 26-X-direction leaf spring; 27-Y-direction leaf spring; 28-Z-direction leaf spring; 29-Rz flexible hinge; 401-Chuck; 402-suction cup ;403-micro motor;404-anti-collision frame;405-macro planar motor mover;406-plane grating reading head;407-leveling and focusing sensor;408-micro planar motor mover;409-gravity compensation 411-magnetic steel array; 412-coil array; 413-wireless charging receiver; 414-wireless communication transceiver.

detailed description

The embodiment of the present invention will be further described in detail below in conjunction with the accompanying drawings: a method for changing the vector arc of a moving coil maglev double workpiece table based on a plane grating measurement, the method includes the following steps: In the initial working state, the first workpiece table at the measurement position is in In the pre-alignment state, the second workpiece stage at the exposure position is in the exposure state; in the first step, after the pre-alignment of the first workpiece stage at the measurement position is completed, it is driven by the moving magnet to move to the predetermined position A of the measurement position and change the stage, charging and waiting, exposure After the exposure of the second workpiece table is completed, it is driven by the moving magnet to move to the predetermined position C of the exposure position; in the second step, the first workpiece table and the second workpiece table move counterclockwise along the arc track through the vector control of the plane motor. In the process, the phase of the two workpiece tables does not change, and the moving position is measured by the plane grating. When the first workpiece table is driven by the moving magnet to move to the predetermined position of the exposure position C, the second workpiece is driven by the moving magnet to move to the measurement position. When it is at the predetermined position D, the stage change is completed, the first workpiece stage performs silicon wafer photolithography exposure at the exposure position, and the second workpiece stage performs silicon wafer loading and silicon wafer pre-alignment operations at the measurement position; the third step, the measurement position After the pre-alignment of the second workpiece table is completed, it is driven by the moving magnetic steel to move to the predetermined position A' of the measuring position and the station is changed, and it is charged and waited. Position C; in the fourth step, the second workpiece table and the first workpiece table move clockwise along the circular arc track through the vector control of the plane motor, when the second workpiece table is driven by the moving magnet and moves to the predetermined position C of the exposure position, the first workpiece When the stage is driven by the moving magnet and moves to the predetermined position D of the measuring position, the changeover is completed, the second workpiece stage at the exposure position enters the exposure state, and the first workpiece stage at the measuring position performs loading and unloading and pre-alignment operations, and the system returns to the initial state at this time In the working state, a working cycle including two channel-changing operations is completed, and wireless communication is used in the process of measurement, exposure and channel-changing.

A vector arc transfer device based on planar grating measurement of moving magnetic steel maglev double workpiece table, the device includes a support frame 1, a balance mass 2, a first workpiece table 4a, a second workpiece table 4b, and a wireless charging transmitter 30 , the balance mass 2 is located above the support frame 1, the macro-motion planar motor stator 3 is installed on the plane on the balance mass 2, and the first work table 4a and the second work table 4b are arranged on the macro-motion planar motor stator (3 ), the first workpiece table 4a and the second workpiece table 4b are arranged above the stator 3 of the macro-motion planar motor, and the first workpiece table 4a and the second workpiece table 4b run between the measurement position 11 and the exposure position 12 , on the first workpiece table 4a and the second workpiece table 4b, respectively install the measuring plane grating 5a and the exposure plane grating 5b on the plane; the supporting frame 1 passes through a motion compensation mechanism composed of a flat leaf spring 13 and an electromagnetic damper 14 in parallel Connected with the balance mass 2, the planar leaf spring 13 is composed of a pair of X-direction leaf springs 26, a pair of Y-direction leaf springs 27, a Z-direction leaf spring 28 and a Rz flexible hinge 29. The electromagnetic damper 14 is composed of damper upper back plate 21, damper lower back plate 25, Y-direction permanent magnet array 24a and X-direction permanent magnet array 24b, red copper plate 22 and stainless steel column 23, wherein the damper upper back plate 21 and damper The lower backplane 25 is connected by stainless steel columns 23, and the permanent magnet arrays 24a and 24b in the Y and X directions are installed between the upper and lower backplanes 21 and 25 of the damper, and form a strong magnetic field between the air gap and a strong magnetic field in the air gap. The red copper plate 22 is installed in the center, the red copper plate 22 is fixed on the support frame 1, the upper back plate 21 of the damper is fixed with the balance mass block 2, and the red copper plate 22 can produce X, Y direction translation and Rz rotates; the first workpiece table 4a and the second workpiece table 4b are six-degree-of-freedom maglev micro-motion tables, and the six-degree-of-freedom maglev micro-motion tables are composed of Chuck401, suction cup 402, micro-motor 403, anti-collision frame 404, macro motion Planar motor mover 405, planar grating reading head 406, leveling and focusing sensor 407, wireless charging receiver 413, and wireless communication transceiver 414. The mover 409 is integrated together, the suction cup 402 is installed on the Chuck401, four planar grating reading heads 406 and four leveling and focusing sensors 407 are installed on the four corners of the Chuck401, and the Chuck401 is fixed on the micro motor 403, An anti-collision frame 404 is installed around the micro-motor 403, and the macro-motion planar motor mover 405 is installed under the anti-collision frame 404. The motor stator 3 is composed of coil arrays 412 arranged in a herringbone shape.

The working process of the present invention is as follows: after the first workpiece table 4a is pre-aligned at the measurement position 11, it is driven by the plane motor to move to the stage change position A, and waits for the second workpiece table 4b to complete the exposure at the exposure position 12, and the second workpiece table 4b After the exposure is completed, it is driven by the planar motor to move to the station-changing position B, and then the first workpiece table 4a and the second worktable 4b move counterclockwise along the circular arc track through the vector control of the planar motor to complete the station-changing operation; after the station-changing is completed, the first The workpiece table 4a moves to the exposure position 12 to perform exposure at the exposure position 12, and the second workpiece table 4b moves to the measurement position 11 to perform loading and pre-alignment operations at the measurement position 11; the second workpiece that is pre-aligned to the silicon wafer is completed first The table 4b moves to the measuring position change position A', waits for the first workpiece table 4a to complete the exposure and then moves to the table change position B', then, the second work table 4b and the first work table 4a are controlled along the circular arc by the plane motor vector control The track moves clockwise to complete the second stage change; after the stage change is completed, the first workpiece stage 4a moves to the measurement position 11, and the second workpiece stage 4b moves to the exposure position 12, thus completing a complete working cycle.

Claims (2)

1. one kind is floated double-workpiece-table vector circular arc channel switching method based on the dynamic magnet steel magnetic of plane grating measurement, it is characterized in that the method comprises the following steps: original operating state, measure position first work stage and be in prealignment state, exposure position second workpiece platform is in exposure status, the first step, to measure after position first work stage prealignment by dynamic magnet steel actuation movement to measuring zapping precalculated position, position A and charging and waiting for, after the second workpiece platform exposure of exposure position by dynamic magnet steel actuation movement to exposing precalculated position, position C, second step, first work stage and second workpiece platform pass through planar motor vector controlled along arc track counterclockwise movement, in motion process, the phase place of two work stage does not change, movement position is measured by plane grating, when the first work stage is by moving magnet steel actuation movement to exposure precalculated position, position C, second workpiece platform by when moving magnet steel actuation movement to measurement precalculated position, position D, zapping terminates, first work stage carries out silicon chip photolithographic exposure in exposure position, and second workpiece platform carries out silicon chip upper slice and wafer pre-alignment operation in measurement position, 3rd step, to measure after position second workpiece platform prealignment by dynamic magnet steel actuation movement to measuring zapping precalculated position, position A' and charging and waiting for, after the work stage exposure of exposure position first by dynamic magnet steel actuation movement to exposing precalculated position, position C, 4th step, second workpiece platform and the first work stage pass through planar motor vector controlled along arc track clockwise movement, when second workpiece platform is by moving magnet steel actuation movement to exposure precalculated position, position C, first work stage is by when moving magnet steel actuation movement to measurement precalculated position, position D, zapping terminates, exposure position second workpiece platform enters exposure status, measure position first work stage and carry out fluctuating plate and prealignment operation, now system gets back to original operating state, complete the work period comprising twice zapping operation, in measurement, wireless communication mode is adopted to complete in exposure and zapping process.

2. one kind is floated double-workpiece-table vector circular arc programme changer based on the dynamic magnet steel magnetic of plane grating measurement, it is characterized in that this device comprises support frame (1), balance mass block (2), first work stage (4a), second workpiece platform (4b), wireless charging transmitter (30), described balance mass block (2) is positioned at support frame (1) top, grand dynamic planar motor stator (3) is arranged in the plane on balance mass block (2), first work stage (4a) and second workpiece platform (4b) are configured in grand dynamic planar motor stator (3) top, described first work stage (4a) and second workpiece platform (4b) run on to be measured between position (11) and exposure position (12), first work stage (4a) and the upper plane of second workpiece platform (4b) install and measure bit plane grating (5a) and exposure bit plane grating (5b) respectively, support frame (1) is connected with balance mass block (2) by the motion compensation mechanism formed that walked abreast by planar chip spring (13) and electromagnetic damper (14), described planar chip spring (13) by 1 couple of X to sheet spring (26), 1 pair of Y-direction sheet spring (27), 1 Z-direction sheet spring (28) and 1 Rz flexible hinge (29) composition, electromagnetic damper (14) is by backboard on damper (21), backboard (25) under damper, Y-direction permanent magnet array (24a) and X are to permanent magnet array (24b), copper plate (22) and stainless steel column (23) assembling are formed, and wherein on damper, backboard (21) is connected by stainless steel column (23) with backboard under damper (25), Y, X is to permanent magnet array (24a, 24b) be installed on damper, lower backboard (21, 25) between, and form high-intensity magnetic field between air gap, install copper plate (22) in air gap high-intensity magnetic field, copper plate (22) is fixed on support frame (1), and on damper, backboard (21) is fixed, relative to upper with balance mass block (2), lower backboard (21, 25) copper plate (22) can produce X, Y-direction translation and Rz rotate, first work stage (4a) and second workpiece platform (4b) are six-freedom-degree magnetic suspension jiggle station, described six-freedom-degree magnetic suspension jiggle station is by Chuck(401), sucker (402), fine motion motor (403), crashproof frame (404), grand dynamic planar motor rotor (405), plane grating read head (406), leveling and focusing sensor (407), wireless charging receiver (413), wireless communication transceiver (414) forms, described fine motion motor (403) is integrated by fine motion planar motor rotor (408) and gravity compensator mover (409) and forms, described sucker (402) is arranged on Chuck(401) on, Chuck(401) four angles are provided with four plane grating read heads (406) and four leveling and focusing sensors (407), Chuck(401) be fixed on fine motion motor (403), in fine motion motor (403) surrounding, crashproof frame (404) is installed, described grand dynamic planar motor rotor (405) is arranged on crashproof frame (404) below, grand dynamic planar motor rotor (405) is formed by magnetic steel array (411) is staggered, grand dynamic planar motor stator (3) becomes herringbone arrangement to form by coil array (412).