Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 ? 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.

Abstract: 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.

Abstract: 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 20 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.

Abstract: 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.

Abstract: 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 ? 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.