Chinese Academy of Sciences

The Institute of Optics and Electronics

Song Hu

Lixin Zhao

Jian Wang

Xianchang Zhu

Yudong Zhang

Yun Dai

Jinlong Li

Xuejun Rao

Wei Yan

Jinhua Feng

Feng Xu

Lanlan Li

Zhuang Sheng

Xiaochun Dong

Yanli Li

Hongtao Gao

The present disclosure relates to a method for detecting focal plane based on a grating Talbot effect, the function of which is to detect position of a silicon wafer in a photolithography machine in real time so as to implement an adjustment of leveling and foal plane of the silicon wafer in a high resolution. The detection system utilizes a phase change of 'self-image' generated by a grating Talbot effect caused by defocusing of the silicon wafer, so as to accomplish the detecting for focal plane of the silicon wafer in the photolithography machine in a high resolution: if the silicon wafer is at a focal plane, the imaged wavefront by the grating is a planar wavefront; and when the silicon wafer is defocused, the imaged wavefront is a spherical wavefront. Such a detection system has a simple structure, a higher anti-interference capability and a perfect adaption of the process.

Method for detecting focal plane based on grating talbot effect

The present disclosure provides a high accuracy measurement system for focusing and leveling. The system determines an off-focus distance in the perpendicular direction within the exposure field and an inclination in the horizontal direction by measuring heights of four detection points on a substrate by using a four-channel detection method, thereby achieving focusing and leveling of the substrate. The detection of the substrate heights is implemented by a focusing method based on dual-channel light intensity modulation. Two superposed grating fringes are formed with phase difference of &#x3c0;/2. The shift can be resolved by the phase variation of corresponding fringes. According to the method, the off-focus distance can be derived. The present disclosure effectively eliminates the error due to the intensity changes caused by the fluctuations of the source or the reflectance of the substrate surface. The apparatus for focusing and leveling is easy to be implemented and has an accuracy of nanoscale.

High accuracy measurement system for focusing and leveling

The present disclosure relates to a method for detecting focus plane based on Hartmann wavefront detection principle, the function of which is to detect the position of a silicon wafer in a photolithograph machine in real time so as to accomplish adjustment of the leveling and focus of the silicon wafer. By utilizing microlens array to detect the wavefront carrying information about the position of the silicon wafer based on the Hartmann wavefront detection principle, the spherical wavefront is divided by the respective subunits of the microlens array and is imaged on the respective focus planes of the subunits. If the silicon wafer is located on the focal plane, the incident wavefront for the microlens array is a planar wavefront so that the diffraction light spots are on the focus of the respective subunits of the microlens array; and if the silicon wafer is defocused, the incident wavefront for the microlens array is a spherical wavefront so that the diffraction light spots are shifted on the focus plane of the microlens array. Based on Hartmann wavefront detection principle, the detection of the spherical wavefront may be implemented by the microlens array shifting the imaged light spots for the plane wavefront and the spherical wavefront, so as to accomplish the defocusing measurement for the silicon wafer. The system for detecting focus plane has a simple configuration, a higher accuracy and efficiency, so it is applied to measurement for detecting the focus plane in various types of photolithography machines in a high accuracy and in real time.

Method for detecting focus plane based on Hartmann wavefront detection principle

Disclosed is a focus detection apparatus for a projection lithography system. The apparatus includes: a laser; a focus optical unit configured to focusing the emitted laser beam; a force detection unit configured to reflect the focused laser beam at the backside; a position detection unit configured to detect variations in position of a light spot formed by the reflected laser beam, and output a strength signal indicating the strength of the interaction force between the force detection unit and the object; a differential amplifier configured to output a Z-direction differential signal based on the strength signal and a reference signal; a Z-direction feedback control unit configured to perform feedback control; and a scan signal generator configured to output a signal for controlling the movement of the stage in the XY plane. The focus detection apparatus has high precision, efficiency and process applicability.

Focus detection apparatus for projection lithography system

A customizing equipment for individualized contact lenses comprises an uniform illumination system, a gray image generation system, a projection optical system, a stage system and an alignment system, among which the uniform illumination system generates uniform parallel illuminative light, which generates gray images through the gray image generator controlled by a computer after going through the gray image generation system according to detection results of aberration of human eyes, and images on the image plane of given radius of curvature with photoresist on the samples' surface, which is fixed on the stage system and adjusted to the correct position through the alignment system, after the gray images are zoomed and the curvature of the image field is corrected through the projection optical system, so that the photoresist on the samples' surface will be exposed according to the gray levels of the gray images, after which the exposed samples are developed and etched to obtain the device with continuous embossment microstructure on the sphere. After the checking and post-processing, this device will result in the individualized contact lenses, which can be worn. This current invention can realizes fast customization of individualized contact lenses.

Customizing equipment for individualized contact lenses

Growing community of inventors

Sichuan, China

Song Hu