Tsinghua University

Beijing U-precision Tech Co., Ltd.

Weinan Ye

Yu Zhu

Ming Lei Zhang

Rong Cheng

Jinchun Hu

Leijie Wang

Li Ni Zhang

Xin Li

Jin Zhang

Li Tian

Kaiming Yang

Wensheng Yin

Zhao Liu

Haihua Mu

Huichao Qin

Fuzhong Yang

Yanpo Zhao

Fan Zhi

Dengfeng Xu

Ming Zhang

Zhaokui Cheng

Yizhou Xia

Ziwen Guo

Disclosed is a heterodyne grating interferometry system based on secondary diffraction, including a single-frequency laser, an input optical fiber, an acousto-optic modulator, a reading head, and a measurement grating, an output optical fiber, a photoelectric conversion unit and an electronic signal processing unit, wherein the single-frequency laser emits a single-frequency laser, which enters the acousto-optic modulator through the input optical fiber, and is divided into a reference light and measurement light to be input to the reading head, wherein the reading head and the measurement grating convert the reference light and measurement light into a reference interference optical signal and a measurement interference optical signal and send them to the photoelectric conversion unit through the output optical fiber and wherein the photoelectric conversion unit converts the measurement interference optical signal and the reference interference optical signal into a measurement interference electrical signal and a reference interference electrical signal.

Heterodyne grating interferometry system based on secondary diffraction

A five-degree-of-freedom heterodyne grating interferometry system comprises: a single-frequency laser for emitting single-frequency laser light, the single-frequency laser light can be split into a reference light beam and a measurement light beam; an interferometer lens set and a measurement grating for converting the reference light and the measurement light into a reference interference signal and a measurement interference signal; and multiple optical fiber bundles respectively receiving the measurement interference signal and the reference interference signal, wherein each optical fiber bundle has multiple multi-mode optical fibers respectively receiving interference signals at different positions on the same plane. The system is not over-sensitive to the environment, is small and light, and is easy to arrange. Six-degree-of-freedom ultra-precision measurement can be achieved by arranging multiple five-degree-of-freedom interferometry systems and using redundant information, thereby meeting the needs of a lithography machine worktable for six-degree-of-freedom position and orientation measurement.

Five-degree-of-freedom heterodyne grating interferometry system

A five-degree-of-freedom heterodyne grating interferometry system, comprising a single frequency laser device () and an acousto-optic modulator (); the single frequency laser device () emits a single frequency laser, and the single frequency laser is coupled by optical fiber and, after being split, enters the acousto-optic modulator () to obtain two linearly polarized lights of different frequencies, one being a reference light, and one being a measurement light; an interferometer lens group () and a measurement grating (), used for forming the reference light and the measurement light into a measurement interference signal and a compensation interference signal; and multiple optical fiber bundles (), respectively receiving the measurement interference signal and the compensation interference signal, each optical fiber bundle () having multiple multimode optical fibers respectively receiving signals at different positions on the same plane. The present measurement system has the advantages of high measurement precision, a large measurement range, not being sensitive to temperature drift, and small overall size, and can be used as a photoetching machine ultra-precision workpiece table position measurement system.

A two-degree-of-freedom heterodyne grating interferometry measurement system, comprising: a single-frequency laser device for emitting a single-frequency laser, and the single-frequency laser can be split into a beam of reference light and a beam of measurement light; an interferometer mirror group and a measurement grating for forming a reference interference signal and a measurement interference signal from the reference light and the measurement light; and a receiving optical fiber for receiving the reference interference signal and the measurement interference signal, wherein a core diameter of the receiving optical fiber is smaller than a width of an interference fringe of the reference interference signal and the measurement interference signal, so that the receiving optical fiber receives a part of the reference interference signal and the measurement interference signal. The measurement system has advantages of insensitivity to grating rotation angle error, small volume, light weight, and a facilitating arrangement.

Two-degree-of-freedom heterodyne grating interferometry measurement system

A coarse motion and fine motion integrated reticle stage driven by a planar motor comprises a movable platform () of the reticle stage, a balance mass (), a drive motor, a mask plate (), a base (), a vibration isolation system (), and a measuring system, wherein, the vibration isolation system is located between the balance mass and the base, and the mask plate is mounted on the movable platform. The drive motor of the movable platform is a moving-iron type planar motor (). The reticle stage can lower the design complexity of the drive motor of the movable platform. Compared with a linear motor, the planar motor can provide push forces in more directions, the number of motors is reduced, the structure of the movable platform is more compact, the inherent frequency and the control bandwidth of the movable platform are improved, and thus control precision is improved.

Coarse motion and fine motion integrated reticle stage driven by planar motor

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 magnetically suspended coarse motion and fine motion integrated reticle stage driven by a planar motor comprises a movable platform (), a balance mass (), a drive motor, a mask plate (), a base (), a vibration isolation system (), and a measuring system, wherein, the vibration isolation system is located between the balance mass and the base, and the mask plate is mounted on the movable platform. The drive motor of the movable platform is a moving-iron type planar motor (). The reticle stage can lower the design complexity of the drive motor of the movable platform. Compared with a linear motor, the planar motor can provide push forces in more directions, the number of motors is reduced, the structure of the movable platform is more compact, the inherent frequency and the control bandwidth of the movable platform are improved, and thus control precision is improved.

Magnetically suspended coarse motion and fine motion integrated reticle stage driven by planar motor

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Beijing, China

Weinan Ye