Tsinghua University

Shanghai Micro Electronics Equipment Co., Ltd.

Beijing U-precision Tech Co., Ltd.

Dengfeng Xu

Yu Zhu

Ming Lei Zhang

Jinchun Hu

Wensheng Yin

Kaiming Yang

Haihua Mu

Rong Cheng

Zhao Liu

Guanghong Duan

Li Tian

Chuxiong Hu

Leijie Wang

Jinsong Wang

Longmin Chen

Jingsong Wang

Hao Liu

Feng Liu

Guang Cheng Li

Anlin Chen

Jing Wang

Li Ni Zhang

Xin Li

Yi Shan Jiang

Jin Zhang

Ming Zhang

Weinan Ye

Dongdong Yu

Fan Zhi

Yanpo Zhao

Huichao Qin

Rujin Han

Chang Tian

Yujing Song

Yaying Chen

Kai Liao

Yuting Sun

Guofeng Ji

A high-resolution phase detection method and system based on a plane grating laser interferometer. The method uses a dual-frequency interferometer to measure the displacement, and the measurement signal processing comprises an integral part and a decimal portion, a phase equation set of a displacement measurement signal is constructed according to a measurement optical path principle of a heterodyne plane grating laser interferometer; a non-linear equation set for which the unknowns are instantaneous phase, interval phase and signal amplitude is established; and the equation sets above are solved by using the least squares method, so as to realize phase discrimination, thereby realizing precise displacement measurement. The method can solve the problems in the traditional time measurement-based phase detection technology, such as low measurement accuracy, and failing to satisfy small measuring range measurement. The measurement method can be applied to systems such as precision manufacturing equipment and lithography machine.

High-resolution phase detection method and system based on plane grating laser interferometer

A magnetic levitation reaction sphere includes a spherical-housing-shaped rotor and three groups of stators. Each group includes two stators using the sphere center of the rotor as a symcenter. Axes of the three groups are mutually orthogonal. Each stator comprises a stator core and a coil array. An air gap is reserved between an inner surface of each stator core and the outer surface of the rotor. Through grooves are radially formed in the stator cores. The coil arrays are disc-type motor stator windings. Two effective sides of each coil in each coil array are respectively placed in two through grooves of the corresponding stator core. The magnetic levitation reaction sphere has low cost; levitation and rotation driving are integrated; the magnetic levitation reaction sphere has a simple and compact structure, a small size and a low mass, and relates to inherent stable levitation; and the levitation control is simple.

Magnetic levitation reaction sphere

A six-degree-of-freedom displacement measurement method for an exposure region on a wafer stage, the wafer stage comprises a coil array and a movable platform. A planar grating is fixed below a permanent magnet array of the movable platform. A reading head is fixed in a gap of the coil array. A measurement region is formed on the planar grating by an incident measurement light beam of the reading head. The reading head measures the six-degree-of-freedom displacement of the measurement region, so that the six-degree-of-freedom displacement of the exposure region is obtained through calculation. In the method, the six-degree-of-freedom displacement of the exposure region at any time is measured; the measurement complexity is reduced and the measurement precision is improved, and especially, the six-degree-of-freedom displacement of the exposure region can be precisely measured at any time even if the movable platform has high flexibility.

Six-degree-of-freedom displacement measurement method for exposure region on silicon wafer stage

A three-DOF (Degree of Freedom) heterodyne grating interferometer displacement measurement system comprises a dual-frequency laser, a grating interferometer, a measurement grating, receivers and an electronic signal processing component; the grating interferometer comprises a polarizing beam splitter, a reference grating and dioptric elements; the measurement system realizes displacement measurement on the basis of grating diffraction, the optical Doppler Effect and the optical beat frequency principle. Three linear displacements can be output by the system when the grating interferometer and the measurement grating perform a three-DOF linear relative motion. The measurement system can reach sub-nanometer and higher resolution and precision, and can simultaneously measure three linear displacements. The measurement system has the advantages of being environmentally insensitive, high in measurement precision, small in size, light in weight, and is capable of improving the overall performances of an ultra-precision stage of a lithography machine as a position measurement system for this stage.

Three-DOF heterodyne grating interferometer displacement measurement system

A dual-frequency grating interferometer displacement measurement system, comprises a dual-frequency laser, an interferometer, a measurement grating and an electronic signal processing component. The measurement system realizes displacement measurement based on grating diffraction, optical Doppler effect and optical beat frequency theory. Dual-frequency laser light is emitted from the dual-frequency laser and split into reference light and measurement light via a polarization spectroscope. The measurement light is incident to the measurement grating to generate positive and negative first-order diffraction. The diffraction light and the reference light form a beat frequency signal containing displacement information about two directions at a photo-detection unit, and linear displacement output is realized after signal processing. The measurement system can realize sub-nanometer and even higher resolution and accuracy, and is able to measure long horizontal displacement and vertical displacement at the same time.

Dual-frequency grating interferometer displacement measurement system

A displacement measurement system of heterodyne grating interferometer, comprises a reading head, a measurement grating and an electronic signal processing component. Laser light emitted from the laser tube is collimated, passes through the first polarization spectroscope, and then emits two light beams with an orthogonal polarization direction and an orthogonal propagation direction; the two light beams pass through two acousto-optic modulators and respectively generate two first-order diffraction light beams with different frequencies, which are later divided into reference light and measurement light; two parallel reference light beams form a beat frequency electric signal with positive and negative first-order diffraction measurement light respectively after passing through a measurement signal photo-electric conversion unit; the beat frequency signals are transmitted to the electronic signal processing component for signal processing, thus the output of linear displacement in two directions is realized.

Heterodyne grating interferometer displacement measurement system

An optical grating phase modulator for a laser interference photoetching system is composed of a substrate, an optical grating, an electric motor and an optical grating positioner. The optical grating, the electric motor and the optical grating positioner are all mounted on the substrate. The optical grating is circular or rectangular, and adopt transmission or reflection type optical grating. A light beam is incident on the optical grating and generates diffraction, and when the electric motor drives the optical grating to continuously move relative to the incident light beam, diffracted light will generate a frequency shift, thereby realizing the phase modulation of the light beam. The optical grating phase modulator has the advantages of high phase modulation speed, high regulation precision and wide regulation range, thereby improving the whole performance of an interference photoetching system.

Optical grating phase modulator for laser interference photoetching system

A planar motor rotor displacement measuring device and its measuring method are provided. The motor is a moving-coil type planar motor. The device comprises probes, two sets of sine sensors, two sets of cosine sensors, a signal lead wire and a signal processing circuit. The method is arranging two sets of magnetic flux density sensors within a magnetic field pitch &#x3c4; along two vertical movement directions in the rotor located in the sine magnetic field area. Sampled signals of the four sets of sensors are respectively processed with a frequency multiplication operation, four subdivision signals are obtained, the zero-crossing points of the four subdivision signals are detected, and then two sets of orthogonal pulse signals are generated. The pulse number of the orthogonal pulse signals is counted, and phase difference of the two sets of orthogonal pulse signals is respectively detected.

Planar motor rotor displacement measuring device and its measuring method

A negative stiffness system for gravity compensation of a micropositioner of wafer table in lithography machine, characterized in that, the negative stiffness system includes at least three sets of quasi-zero stiffness units, each of the sets of quasi-zero stiffness units comprises a pair of negative stiffness springs and a positive stiffness spring, the positive stiffness spring is vertically positioned, the pair of negative stiffness springs are obliquely and symmetrically positioned at two sides of the positive stiffness spring, upper ends of the negative stiffness springs and the positive stiffness spring are connected together and fixed to the bottom surface of a rotor of the micropositioner, and lower ends of the negative stiffness springs and the positive stiffness spring are connected to a base, respectively. The system reduces the stiffness in vertical direction and prevents the influence of permanent magnet on its surroundings, while improving the bearing capacity.

Negative stiffness system for gravity compensation of micropositioner

Disclosed is a dual wafer stage switching system for a lithography machine. The system comprises a base stage (), a wafer stage () running at a pre-processing workstation, and a wafer stage () running at an exposure workstation. A rotating motor () is mounted under the base stage () for rotating the two wafer stages after the wafer stages have completed pre-processing and exposure operations in order to complete position switch of the wafer stages, wherein the base stage () is kept stationary during the switch. The present invention avoids rotation of a large inertia base stage and has low requirement for motor power, while eliminating a guide rail docking device and an auxiliary device and greatly simplifying system configuration. The system is easy and convenient to operate and easy to control.

Dual wafer stage switching system for a lithography machine

A two-dimensional locating method of a motion platform based on a magnetic steel array involves the following steps: placing more than four linear Hall sensors at any different positions within one or more polar distances of the magnetic steel array on the surface of the motion platform in a motion system; determining a magnetic flux density distribution model according to the magnetic steel array; determining the mounting positions of the above-mentioned linear Hall sensors, which are converted into phases with respect to the mass center of the motion platform; recording the magnetic flux density measured values of the linear Hall sensors as the motion proceeds; solving the phases of the mass center of the motion platform in a plane, with the measured values being served as observed quantities and the magnetic flux density distribution model being served as a computation model; and determining the position of the mass center of the motion platform with respect to an initial phase according to the phase, so as to realize the planar location of the motion platform. The present invention provides a simple, fast and robust method for computing mass center positions for a motion system containing a magnetic steel array.

Two-dimensional locating method of motion platform based on magnetic steel array

A method for measuring the displacement of a planar motor rotor. The measuring method comprises: four magnetic induction intensity sensors are distributed on the planar motor rotor; sampled signals of the four distributed sensors are processed to obtain signals B, B, Band Band magnetic field reference values B, B, Band B; and X-direction displacement and Y-direction displacement can be measured respectively according to inequalities (I) and (II) by judgments, wherein &#x394;and &#x394;are X-direction displacement resolution and Y-direction displacement resolution respectively, and BM is the magnetic induction intensity amplitude of the magnetic field of said planar motor. The method provided by the invention is simple in calculation, can avoid calculation of a transcendental function and solve the quadrant judgment problem, is favorable to real-time high-speed operation and has a high engineering value. 

Method for measuring displacement of planar motor rotor

A single degree of freedom vibration isolating device of a linear motor and a motion control method thereof. The vibration isolating device comprises a balance block, an anti-drifting driving unit, and a control unit. An upper surface of the balance block is connected to a stator of the linear motor, and a lower surface of the balance block is connected to a base. The anti-drifting driving unit is connected to the balance block for controlling the position of the balance block. Provided two motion control methods: inputting a second grating ruler signal to the control unit as feedback to perform variable stiffness and nonlinear control on the balance block; inputting a first and a second grating ruler signal to the control unit as feedback to obtain resultant centroid displacement signals of the rotor and the balance block to perform nonlinear anti-drifting control on the balance block.

Single degree of freedom vibration isolating device of linear motor and motion control method thereof

A method for measuring displacement of a large-range moving platform, comprising: arranging multiple beams of first measuring light parallel to one another and generated by an optical path distribution device and a position sensitive detector array in a certain manner, to ensure that at least one beam of first measuring light is detected by the position sensitive detector array when a moving platform is at any position of a moving area; a detection head array capable of determining whether a light beam is shaded being used for auxiliary measurement of a position of the moving platform; and determining a position of the moving platform that corresponds to the first measuring light measured by the position sensitive detector array, to calculate displacement of the moving platform. The method effectively enlarges a measurement range of the position sensitive detector array, and implements measurement of long range displacement of the moving platform.

Method for measuring displacement of large-range moving platform

A dual wafer stage exchanging system for a lithographic device is disclosed, said system comprises two wafer stages running between an exposure workstation and a pre-processing workstation, and said two stages are set on a base and suspended above the upper surface of the base by air bearings. Each wafer stages is passed through by a Y-direction guide rail respectively, wherein one end of said guide rail is connected with a main driving unit and another end of said guide rail is detachably coupled with one of the two X-direction auxiliary driving units with single degree of freedom, and said two wafer stages are capable of moving in Y-direction along the guide rails and moving in X-direction under the drive of the auxiliary driving units with single degree of freedom. The position exchange of said two wafer stages can be enabled by the detachment and connection of the Y-direction guide rails and the auxiliary units with single degree of freedom.

Growing community of inventors

Beijing, China

Dengfeng Xu