Exposure beam phase measurement method in laser interference lithography and lithography system

Abstract

The invention belongs to the technical field of optical instruments and meters, and discloses an exposure beam phase measurement method in laser interference lithography. The method comprises the steps: separating measuring light from an exposure light beam of laser interference lithography and inputting the measuring light into a laser phase measuring interferometer to carry out phase measurementon the exposure light beam of laser interference lithography; and introducing a reference light beam homologous with the laser interference lithography exposure light beam, inputting the reference light beam into the laser phase measuring interferometer, processing the reference light beam by the laser phase measuring interferometer to form an interference measurement light signal, and performingresolving to obtain the phase of the laser interference lithography exposure light beam. The invention discloses a laser interference lithography system. The system comprises the laser phase measurement interferometer, a controller and a phase modulator; the system adopts the exposure light beam phase measurement method in laser interference lithography, and the laser phase measurement interferometer is used for measuring whether the phase of the exposure light beam drifts or not; the controller controls the phase modulator to carry out phase modulation, the locking of exposure fringe phase drift is completed, and the manufacturing of a high-precision variable-period grating is achieved.

Description

technical field [0001] The invention belongs to the technical field of optical instruments and meters, and in particular relates to a method for measuring the phase of an exposure beam in laser interference lithography and a lithography system. Background technique [0002] Grating devices are key devices in major engineering systems such as large astronomical telescopes, inertial confinement fusion laser ignition systems, and photolithography systems. In recent years, the requirements for size, grid line density, and accuracy have been continuously improved. Limited to one-dimensional gratings, it also includes two-dimensional gratings, curved gratings, variable period gratings, etc. The grating manufacturing is moving towards the order of meter-scale size, nano-scale precision, and sub-million-level grating line density. Diversified high-precision dense grating lines The manufacture of large-scale gratings has become a hot issue that needs to be solved urgently in the fiel...

AI Technical Summary

Problems solved by technology

The measurement signal of the dual-channel homodyne phase measurement interferometer is a DC signal, which has poor anti-interference ability and is difficult to achieve high-precision measurement. It is also difficult to solve the phase, subdivide and judge the direction.

[0007] U.S. Patent No. 6,882,477B1 discloses a scanning laser interference lithography system. The lithography system uses two collimated small-sized beams to interfere to form an interference pattern and expose a substrate for step-and-scan movement to realize large-area grating production. , the collimated small-size beam interference effectively eliminates the phase nonlinear error of the interference pattern; at the same time, in order to prevent the phase drift of the system interference pattern relative to the moving substrate platform from causing errors, the lithography system lists a method based on A pattern locking device based on the principle of heterodyne measurement. This device generates the frequency difference of heterodyne phase measurement by arranging three acousto-optic modulators in the interference optical path, and uses a beam sampler to sample the interference beam to the heterodyne phase meter for pattern phase detection. The phase is fed back to the controller to control the modulation phase of the acousto-optic modulator to achieve pattern locking; this device has the advantages of high-speed, high-precision pattern phase locking, etc., but when manufacturing variable-period gratings, the offset of the exposure beam will cause the measurement beam spot Separate, non-measurable and real-time fringe-locked to variable-period interferometric exposure systems

[0008] In summary, the phase measurement of the exposure beam in the existing technical solutions has certain limitations, and it is difficult to realize real-time measurement for fringe control of the variable-period interference exposure system

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