Chinese semiconductor industry

In response to the ultra-precision and high-speed displacement measurement requirements put forward in high-end equipment such as microelectronic lithography machines, Harbin Institute of Technology has deeply explored the traditional common optical path heterodyne laser interferometry method and a new generation of non-common optical path heterodyne laser interferometry methods. It has made continuous breakthroughs in many key technologies such as high-precision laser frequency stabilization, precise suppression of optical nonlinear errors, high-speed and high-resolution interference signal processing, and has developed a series of ultra-precision high-speed laser interferometers with the highest relative accuracy of laser vacuum wavelength. 9.6×10 -10 , the displacement resolution is 0.077 nm, the minimum optical nonlinearity error is 13 pm, and the maximum measurement speed is 5.37 m/s. At present, this series of instruments has been successfully used in the field of integrated development and performance testing of lithography machine prototypes with multiple process nodes from 350 nm to 28 nm in my country, providing key technical support and important measurement methods for the development of high-end equipment such as lithography machines in my country.

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In the development of domestic lithography machines, the multi-axis high-speed ultra-precision laser interferometer is one of the core units embedded in the lithography machine and determines its lithography accuracy. However, on the one hand, European and American countries clearly stipulated that this type of interferometer products are strictly embargoed to my country in the Wassenaar Agreement; Development and production of domestic lithography machines. To this end, our research group has developed a series of ultra-precision high-speed laser interferometry systems, which have been successfully applied in the field of integrated development and performance testing of lithography machine prototypes with multiple process nodes from 350 nm to 28 nm in my country. Typical applications such asFigure 18As shown in the figure, all its key indicators meet the research and development needs of domestic advanced lithography machines, break the embargo blockade imposed by foreign related products on my country, and play an important role in the development of domestic lithography machines. In the applied lithography machine, the number of measurement axes of the interferometer can reach more than 22 axes, the maximum measurement speed can reach 5.37 m/s, and the laser vacuum wavelength/frequency accuracy can reach up to 9.6 × 10 -10 ( k = 3 ), the displacement resolution can reach 0.077 nm, and the minimum optical nonlinearity error is 13 pm. With the ultra-stable constant temperature air bath (3~5 mK@10 min) and vibration isolation environment, the linear displacement and angular displacement can be measured and decoupled synchronously for the multi-dimensional motion of the double workpiece stage in the lithography machine to meet the requirements of the mask. The increasingly complex relative position/attitude measurement requirements between the workpiece table, the silicon wafer workpiece table and the projection objective lens, thereby ensuring the overall overlay accuracy of the lithography machine.​

-Testing in some precision measuring instrument​