NL1042221B1 - Arc vector rotation wafer stage switching method and device based on plane grating measurement for dynamic magnetic maglev dual-wafer stage - Google Patents

Abstract

Disclosed in this application is an arc vector rotation wafer stage switching device based on plane grating measurement for dynamic magnetic maglev dual-wafer, which comprises two wafer stages operated between a measurement position and an exposure position, a plane grating in the measurement position and plane a grating in the exposure position are installed on the planes of the first wafer stage and second wafer stage, respectively. The device optimizes the existing multi-beat linear switcher of the dual-wafer as a single-beat quick switch with less starting and stopping times and less stabilizing links. Meanwhile, the arc trajectory planning is adopted to shorten the trajectory of the stage switching, the impact of the rotation is reduced and the setting time is shortened and finally can realize high efficiency and high precision of a lithography system.

Description

TITLE: ARC VECTOR ROTATION WAFER INTERNSHIP SWITCHING METHOD AND DEVICE BASED ON PLANE GRATING MEASUREMENT FOR DYNAMIC MAGNETIC MAGLEV DUAL-WAFER INTERNSHIP

FIELD OF THE INVENTION

The present invention belongs to semiconductor manufacturing equipment technical field, mainly related to an arc vector rotation wafer stage switching method and device based on plane grating measurement for the dynamic magnetic maglev dual-wafer stage.

BACKGROUND OF THE INVENTION

Lithography machine is one of important ultra-precision equipment in cosmic scale integrated circuit manufacturing. Wafer stage, the key subsystem of the lithography machine, to a large extent establishes the resolution, precision and productivity of the lithography machine.

Productivity is the main goal of the lithography development, with requirements of resolution and accuracy, improve the stage operating efficiency to improve the lithography machine productivity is the development direction of the stage technology. The most direct way to improve the operating efficiency of the stage is to improve the acceleration and velocity of the stage, however, unlimited increase the acceleration and velocity will reduce the original precision. The initial wafer was designed with only one silicon wafer fixed device, the lithography machine can only manufacture one silicon wafer under a serial process, the productivity is low, so a dual-wafer stage is proposed, which is the most effective method to improve the productivity of the lithography machine. The dual-wafer stage is equipped with two exposure, pre-treatment stations and two wafers. Exposure and measurement adjustments can be processed in parallel, which greatly reduces the time and improves production efficiency. The current representative products are dual-wafer technology lithography machine based on Twin-scan technology of the ASML company in the Netherlands.

Currently, improving the operating efficiency of the dual-wafer stage is one of the technical development goals of the lithography machine. Dual-wafer technology involves the problem that two wafer stages switch between the two stations, this switching efficiency directly affects the wafer stage work efficiency and lithography productivity. How to reduce the wafer stage switching time and minimize the interference of the other systems has the focus of this study. In the conventional dual-wafer stage switching process, the wafer stages in the exposure and pre-treatment processes as a linear drive, in the dual-wafer stage patent US2001 / 0004105A1 and W098 / 40791, each wafer stage has two exchangeable units to achieve the dual-wafer stage switching process, improving the productivity without increasing the operating speed of the stage, but due to the coupling connection between the work station and the rail station, the wafer stage will briefly separate from the driving unit in the process of switching , which will make greater influence on the positioning accuracy of the wafer stage. At the same time, the movement unit and the guide rail are longer, the movement quality is bigger, it will generate the adverse effect on the speed and acceleration enhancement movement. China Patent No. CN101609265 proposes a planar motor-driven silicon wafer multi-table switching system, in which a stator motor or a planar motor is arranged on the top of a base and a mover is arranged on the bottom of the silicon wafer table, and the wafer stage and the driving unit are not separated relative to the linear motor drive. In Chinese patent no. CN101694560, a dual-wafer stage switching system driven by airfoil support permanent magnet planar motor is proposed, and the wafer stage is driven by a planar motor and supported by air float, so as to avoid the above problem that the driving units and the wafer stages are separated during the switching process, meanwhile, reduce the wafer stage running resistance, reduce the plane motor drive current, reduce the heat problem.

Comparing with the linear wafer stage switching strategy mentioned in the above patent, the rotating wafer stage switching strategy has a unique advantage, then the dual-wafer stage with rotating switching technology is designed. China Patent No. CN101071275 adopts the method of turning the entire base to realize the transposition of the dual-wafer stage, simplifying the structure of the system, and the two wafer stages are not overlapped with each other, avoid the hidden danger of collision . However, there is a large inertia when turns the whole pedestal to achieve the wafer stage transposition, which raises several problems, such as high-power rotary motor precision positioning difficulties and large heat cause the system temperature rise, meanwhile, the big radius of rotation make the lithography main structure increasing. China Patent No. CN102495528, the invention adopts a rotary transfer table in the center of the base station to complete the switching process or the dual-wafer stages, which are divided into three steps, but the rotary positioning accuracy is low.

The position accuracy of the wafer stage directly affects the position accuracy of the wafer stage of the lithography machine, thus affect the minimum line width of the lithography machine. As the speed of the wafer stage is high, measurement program must meet the high-speed measurement and accuracy requirements.

In the US patent US6498350B2 and US20100279232A1, the invention adopts a number of laser interferometer to achieve a wafer position measurement, the use of laser interferometer measurement of high precision, long working distance, but the measuring light path is too long, the error caused by the humidity and air turbulence is very sensitive and costly.

SUMMARY OF THE INVENTION

In order to solve the shortcomings of the existing technology, the invention provides an arc vector rotation wafer stage switching method and device based on plane grating measurement for the dynamic magnetic maglev dual-wafer stage, which can realize the single-beat fast arc changing or the wafer stage, reduce the wafer switching time, increase the lithography machine production efficiency.

Object of the present invention is implemented as follows: an arc vector rotation wafer stage switching method and device based on plane grating measurement for dynamic magnetic maglev dual-wafer stage, the method comprises the following steps: initial working status, the first wafer stage is in the pre-alignment state in the measurement position, the second wafer stage is in the exposure state in the exposure position; The first step, after pre-alignment completed in the measurement position, the first wafer stage is driven by moving magnet to the preset position A or the measurement position, charge and wait. After exposure completed in the exposure position, the second wafer stage driven by moving magnet to the preset position C or the exposure position. The second step, the first wafer stage and the second wafer stage move counterclockwise along the circular arc path through the vector control of the planar motor. During the movement, the phases of the two wafers are not changed and the movement position is measured by the plane grating. When the first wafer stage is moved to the preset position C in the exposure position and the second wafer stage is moved to the preset position D in the measurement position, the switching wafer stage process is completed. The silicon wafer in the first wafer are lithographed and exposed in the exposure position and the new silicon wafer replace the finished one and be pre-aligned in the second wafer stage in the measurement position. The third step, after pre-alignment completed in the measure position, the second wafer stage is driven by moving magnet to the preset position A or the measurement position, charge and wait. After exposure completed in the exposure position, the first wafer stage driven by moving magnet to the preset position C or the exposure position. The fourth step, the second wafer stage and the first wafer stage move clockwise along the circular arc path through the vector control of the planar motor. When the second wafer stage is moved to the preset position C in the exposure position and the first wafer stage is moved to the preset position D in the measurement position, the wafer stage switching process is completed, the silicon wafer in the second wafer is lithographed and exposed in the exposure position and the new silicon wafer replace the finished one and be prealigned on the first wafer stage in the measurement position. At this time, the system back to the initial working state, including completion of a two switching table operation or a work cycle, the measurement, exposure and table switching process are all completed with wireless communication.

It’s an arc vector rotation wafer stage switching device based on plane grating measurement for dynamic magnetic maglev dual-wafer, the device comprising a support frame, a balance weight block, the first wafer stage, the second wafer and a wireless charging transmitter. The balance weight block is positioned above the support frame, the macro stationary flat motor stator mounted on the flat surface of the balance weight block, the first wafer stage and the second wafer stage are released above the plane macro motion motor stator. The above two wafer stages are operated between the measurement position and exposure position, plane grating in the measurement position and plane grating in the exposure position are installed on the planes of the first wafer stage and second wafer stage, respectively. The support frame is connected with the balance weight block by the motion compensating mechanism composed of the planar leaf spring and the electromagnetic damper in parallel, the planar leaf spring is composed of a pair or X direction leaf spring, a pair Y direction lead spring, a Z direction leaf spring and a Rz flexible hinge. The electromagnetic damper is composed of the upper back plate of the damper, the lower back plate of the damper, the Y-shaped permanent magnet array, the X-shaped permanent magnet array, the copper plate and the stainless-steel column, the upper back plate of the damper and the lower plate of the damper are connected by a stainless steel column. AY, X direction permanent magnet array is installed between the upper and lower dampers of the damper, and the strong magnetic field is formed in the air gap, the copper plate is installed in the strong magnetic field or the air gap, the copper plate is fixed on the support frame, the back plate of the damper is fixed with the balance weight block, and the X, Y and Rz rotations can be produced with respect to the upper and lower back copper plates; The first wafer stage and the second wafer stage are six-DOF magnetic floating micro-stage, which is composed of chuck, sucker, fretting motor, anti-collision frame, macro moving motor and wireless communication transceiver. The fretting motor is composed of a micro-planar motor mover and a gravity compensator mover. The sucker is mounted on a Chuck, which is equipped with four planar grating reading heads and four leveling sensors on four corners. Chuck is fixed to the fretting engine, and a bumper frame is mounted around the fretting engine. The macro dynamic planar electric motor is arranged below the crashing frame. The moving motor or the macro moving planar motor is made up of the staggered arrangement of the magnetic steel arrays. The stator of the macro moving planar motor is arranged in herringbone arrangement or the coil array.

The invention has the following innovation points and outstanding advantages: 1) Propose an arc vector rotation wafer stage switching method and design the corresponding device. The invention adopts the vector wafer stage switching strategy to optimize the existing multi-beat linear switcher or the dual-wafer as a single-beat quick switch with less starting and stopping times and less stabilizing links. Meanwhile, the arc trajectory planning is adopted to short and the trajectory of the stage switching, the impact of the rotation is small and the setting time is short. At the same time, real-time measurement system monitoring or exchange process can ensure macro / micro positioning precision and direct trace to laser wavelength, and finally realize high efficiency and high precision of both sides. This is the first innovation and outstanding advantages of the present invention. 2) Propose a wireless power and wireless wafer stage switching method without cable interference and design the corresponding device. The device is based on the floating magnetic drive, wireless power and wireless signal transmission, to realize the two micro-stage power and communication signals, wireless transmission and control, which make the overall construction compact.

More importantly, it eliminates the cable and signal cable disturbance on the positioning accuracy or dual-wafer stage, which achieves the wireless power supply, wireless communication data transmission and cable-free bondage. This is the second innovation and outstanding advantages of the present invention 3) Propose a magnetic floating plane motor driving method based on the moving magnet and design the corresponding vector plane motor device. The composite current drives have the advantages of high power density, good dynamic performance, high winding utilization rate, uniform temperature distribution, small thermal deformation, etc. It can realize high-efficiency vector control and realize the synthesis and decomposition of six-degree- of-freedom vector force. Meanwhile, this invention adopts dynamic steel driving, wireless communication data transmission, no cable binding, simple structure and high positioning accuracy, which are the third innovation and outstanding advantages of the invention. 4) Propose a measurement method based on planar grating and design the corresponding planar grating measuring device. Compared with the flat grating measuring system, the laser interferometer system can measure the measuring demand or the lithography system at the measuring speed. At the same time because of its small measurement noise, measurement accuracy is higher than the laser interferometer, in particular, it avoids the risk of chuck table plane mirror right angle mirror manufacturing difficulty and high cost with low quality, excessive inertia, which is the fourth innovation and outstanding advantages of the invention. 5) Propose a passive compensation method and an impulse balance method, design a passive compensation mechanism and a balanced mass mechanism based on parallel planar spring and electromagnetic damper. The mechanism can realize the balance mass block motion compensation in X direction, Y direction, Z direction and Rz direction. Compared with the active compensation structure, the complexity of the mechanism is reduced, and the difficulty of control and implementation is reduced, which is the fifth innovation and outstanding advantages of the invention.

LETTER DESCRIPTION OF THE DRAWINGS FIG.1 (a) - (i) are schematic diagrams or quick arc wafer switching in single-beat optimization. FIG.2 is a schematic diagram of the overall structure of the vector arc switcher based on the planar grating measurement for the dynamic magnetic maglev dualwafer stage. FIG.3 is a sectional view of the dual-wafer stage system. FIG.4 is a diagram of motion compensation mechanism and balance weight block assembly structure. FIG.5 is a structural diagram of the planar spring. FIG.6 is a structural diagram of the electromagnetic damping. FIG.7 is a schematic diagram of the electromagnetic damping magnet arrangement. FIG.8 is a schematic diagram of the six-DOF maglev stage. FIG.9 is a schematic diagram of the integrated mechanism of the motion and gravity compensator of the micro-planar motor. FIG.10 is a schematic diagram of a magnetic rigid array arrangement of the moving motion of a planar motor. FIG.11 is a schematic diagram or stator coil array arrangement or planar motor.

The part number in the figures: 1 - support frame; 2 - balancing weight system; 3 - macro moving planar motor stator; 4a - first wafer stage; 4b - second wafer stage; 5a - plane grating in the measurement position; 5b - plane grating in the exposure position; 11 - measurement position; 12 - exposure position; 13 - parallel leaf spring; 14 - electromagnetic damper; 21 - damper upper plate; 22 - copper plate; 23 - stainless steel column; 24a - Y direction permanent magnet array; 24b - X direction permanent magnet array; 25 - damper lower plate; 26 - X direction leaf spring; 27 - Y direction leaf spring; 28 - Z direction leaf spring; 29 - Rz flexible hinge; 401 Chuck; 402 sucker; 403 - fretting engine; 404 - bumper frame; 405 - macro moving motor mover; 406 - plane grating reading head; 408 - micro plane electric motor; 409 - gravity compensator mover; 411 - magnet steel array; 412 - coil array; 413 - wireless charging receiver; 414 - wireless communication transceiver.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Combined with the following appended drawing, the invention implementation plan for further details, the method comprises the following steps: initial working status, the first wafer stage is in the pre-alignment state in the measurement position, the second wafer stage is in the exposure state in the exposure position; The first step, after pre-alignment completed in the measure position, the first wafer stage is driven by moving magnet to the preset position A or the measurement position, charge and wait. After exposure completed in the exposure position, the second wafer stage driven by moving magnet to the preset position C or the exposure position. The second step, the first wafer stage and the second wafer stage move counterclockwise along the circular arc path through the vector control of the planar motor. During the movement, the phases of the two wafers are not changed and the movement position is measured by the plane grating. When the first wafer stage is moved to the preset position C in the exposure position and the second wafer stage is moved to the preset position D in the measurement position, the switching wafer stage process is completed, the silicon wafer in the first wafer is lithographed and exposed in the exposure position and the new silicon wafer replace the finished one and be pre-aligned on the second wafer stage in the measurement position. The third step, after pre-alignment completed in the measure position, the second wafer stage is driven by moving magnet to the preset position A or the measurement position, charge and wait. After exposure completed in the exposure position, the first wafer stage driven by moving magnet to the preset position C or the exposure position. The fourth step, the second wafer stage and the first wafer stage move clockwise along the circular arc path through the vector control of the planar motor. When the second wafer stage is moved to the preset position C in the exposure position and the first wafer stage is moved to the preset position D in the measurement position, the switching wafer stage process is completed, the silicon wafer in the second wafer is lithographed and exposed in the exposure position and the new silicon wafer replace the finished one and be pre-aligned on the first wafer stage in the measurement position. At this time the system back to the initial working state, including completion of a two switching table operation or a work cycle, the measurement, exposure and table switching process are all completed with wireless communication.

It's an arc vector rotation table switching device based on plane grating measurement for dynamic magnetic maglev dual-wafer, the device comprises a support frame 1, a balance weight block 2, the first wafer stage 4a, the second wafer 4b and wireless charging transmitter 30 The balance weight block 2 is positioned above the support frame 1, the macro stationary flat motor stator 3 mounted on the flat surface of the balance weight block 2, the first wafer stage 4a and the second wafer stage 4b are released above the plane macro. motion motor stator 3. The first wafer stage 4a and second wafer stage 4b are operated between the measurement position 11 and exposure position 12, the measurement position plane grating and the exposure position plane grating are installed on the planes of the first wafer stage 4a and second wafer stage 4b, respectively. The support frame 1 is connected to the balance weight block 2 by the motion compensating mechanism composed of the planar leaf spring 13 and the electromagnetic damper 14 in parallel, the planar leaf spring is composed of a pair or X direction leaf spring 26, a pair Y direction lead spring 27, a Z direction leaf spring 28 and an Rz flexible hinge 29. The electromagnetic damper 14 is composed of the upper back plate of the damper 21, the lower back plate of the damper 25, the Y-shaped permanent magnet array 24a, the X-shaped permanent magnet array 24b, the copper plate 22 and the stainless steel column 23, the upper back plate of the damper 21 and the lower plate of the damper 25 are connected by a stainless steel column 23. AY, X direction permanent magnet array 24a, 24b is installed between the upper and lower dampers of the damper 21.25, and the strong magnetic field is formed in the air gap, the copper plate 22 is installed in the strong magnetic field of the air gap , the copper plate 22 is fixed on the support frame 1, the back plate of the damper 21 is fixed with the balance weight block 2, and the X, Y and Rz rotations can be produced with respect to the upper and lower back plates 21.25, copper plate 22; The first wafer stage 4a and the second wafer stage 4b are six-DOF magnetic floating micro-stage, which is composed of Chuck 401, sucker 402, fretting motor 403, anti-collision frame 404, macro moving motor 405, plane grating reading head 406, leveling and focusing sensor 407, wireless charging receiver 413 and wireless communication transceiver 414. The fretting motor 403 is composed of a micro-planar motor mover 408 and a gravity compensator mover 409. The sucker 402 is mounted on a Chuck 401, which is equipped with four planar grating reading heads 406 and four leveling sensors on four corners 407. Chuck 401 is fixed to the fretting motor 403 and a bumper frame 404 is mounted around the fretting motor 403. The macro dynamic planar electric motor 405 is arranged below the crashing frame 403. The moving motor of the macro moving planar motor 405 is made up of the staggered arrangement of the magnetic steel arrays 411. The stator of the macro moving planar motor 3 is arranged in a he rringbone arrangement or the coil array 412.

Present invention workflow is as follows: After pre-alignment completed in the measure position 11, the first wafer stage 4a is driven by moving magnet to the table switching position A and wait the exposure of the second wafer 4b in the exposure position 12. After exposure completed in the exposure position, the second wafer stage 4b driven by moving magnet to the table switching position B, the first wafer stage 4a and the second wafer stage 4b are moved counterclockwise along the circular arc path by the planar motor vector control to complete the table switching operation. After the table switching completed, the first wafer stage 4a is moved to the exposure position 12 to be exposed, and the second wafer stage 4b is moved to the measuring position 11 to change and pre-align the silicon wafer. After the wafer pre-alignment completed, the second wafer stage 4b is moved to the table switching position A "in the measurement position, and waiting the first wafer stage 4a is moved to the table switching position B" after the completion of the exposure. Then, the second wafer stage 4b and the first wafer stage 4a are moved clockwise along the arc path by the planar motor vector control to complete the second table switching process. After the table switching completed, the first wafer stage 4a moves toward exposure position 11 and the second wafer stage 4b moves toward exposure position 12, thus complete an integrated work cycle.

Claims (2)

1. Arc vector rotation "wafer stage" interchange method and device based on plane grating measurement for dynamic magnetic maglev "dual-wafer stage", in an initial operating state, the first "wafer stage" in the pre-alignment state is in the measuring position, the second "wafer stage" is in the exposure state in the exposure position, the method comprising the following steps: after pre-alignment is completed in the measuring position, driving the first "wafer stage" by moving magnet to the preset position A of the measuring position, loading and wait; after exposure has been completed in the exposure position, the second "wafer stage" is driven by moving magnet to the preset position C of the exposure position; moving the first "wafer stage" and the second "wafer stage" counterclockwise along the circular arc path by the vector control of the planar motor; during the movement, the phases of the two wafers are not changed and the movement position is measured by the flat grating; when the first "wafer stage" is moved to the preset position C in the exposure position and the second "wafer stage" is moved to the preset position D in the measurement position, the "wafer stage" swap process is complete; the silicon wafer "in the first" wafer stage "is lithographed and exposed in the exposure position and the new silicon wafer replaces the finished one and is pre-aligned with the second" wafer stage "in the measurement position; after pre-alignment is completed in the measurement position, driving the second "wafer stage" by moving magnet to the preset position A of the measuring position, loading and waiting; after exposure has been completed in the exposure position, the first "wafer stage" driven by moving magnet to the preset position C of the exposure position; and moving the second "wafer stage" and the first "wafer stage" clockwise along the circular arc path through the vector control of the planar motor; when the second "wafer stage" is moved to the preset position C in the exposure position and the first "wafer stage" is moved to the preset position D in the measurement position, the "wafer stage" change process is completed; the silicon "wafer" in the second "wafer stage" is lithographed and exposed in the exposure position and the new silicon "wafer" replaces the finished one and is aligned with the first "wafer stage" in the measuring position; at this time, the system is back in the initial operating state, including completion of a two swap table operation of a work cycle, the measurement, exposure, and table swap process are all completed with wireless communication. 2. Arc vector rotation table changer based on flat grating measurement for dynamic magnetic maglev dual "wafer stage", the device comprising a support frame (1), a balance weight block (2), a first "wafer stage" (4a), a second "wafer stage" (4b ) and a wireless charging transmitter (30); the balance weight block (2) is positioned above the support frame (1), a macro-stationary flat motor stator (3) is mounted on the flat surface of the balance weight block (2), the first "wafer stage" (4a) and the second " wafer stage "(4b) are arranged above the flat macro-motion motor stator (3); the first "wafer stage" (4a) and the second "wafer stage" (4b) are operated between a measuring position (11) and an exposure position (12), a measuring position surface grating and an exposure position surface grating are respectively installed on the surfaces of the first "wafer" stage "(4a) and second" wafer stage "(4b); the support frame (1) is connected to the balance weight block (2) by a motion compensating mechanism which is composed of a planar leaf spring (13) and an electromagnetic damper (14) in parallel arrangement, the planar leaf spring is composed of a pair of X- directional leaf springs (26), a pair of Y-directional leaf springs (27), a Z-directional leaf spring (28) and an Rz flexible hinge (29); the electromagnetic damper (14) is composed of an upper rear plate of the damper (21), a lower rear plate of the damper (25), a Y-shaped permanent magnet array (24a), an X-shaped permanent magnet array ( 24b), a copper plate (22) and a stainless steel column (23), the top rear plate of the damper (21) and the bottom plate of the damper (25) being connected by a stainless steel column (23); a Y, X-direction permanent magnet array (24a), (24b) is installed between the upper and lower dampers of the damper (21), (25), and the strong magnetic field is formed in the air gap, the copper plate (22) is installed in the strong magnetic field of an air gap, the copper plate (22) is fixed on the support frame (1), the rear plate of the damper (21) is fixed with the balance weight block (2), and the X, Y and Rz rotations can be produced relative to the upper and lower rear plates (21), (25), the copper plate (22); the first "wafer stage" (4a) and the second "wafer stage" (4b) are a six-DOF magnetic floating "micro-stage", which is composed of a "chuck" (401), a piston (402), a "fretting motor" (403), an anti-collision frame (404), a macro-moving motor (405), a flat rail reading head (406), a leveling and focusing sensor (407), a wireless loading receiver (413) and a wireless communication transceiver (414); the "fretting motor" (403) is composed of a micro-planar motor mover (408) and a gravity compensator mover (409); the piston (402) is mounted on a "chuck" (401), which is equipped with four planar grating readers (406) and four leveling sensors at four corners (407); the "chuck" (401) is fixed to the "fretting" engine "(403) and a bumper frame (404) is mounted around the" fretting engine "(403); the macro-dynamic planar electric motor (405) is arranged under the collision frame (403); the moving motor of the macro-moving planar motor (405) consists of the staggered arrangement of the magnetic steel arrays (411); and the stator of the macro-moving planar motor (3) is arranged in a herringbone arrangement of the coil array (412).