Method for improving femtosecond laser processing accuracy

Abstract

The invention discloses a method for improving the femtosecond laser processing accuracy. The method includes the steps that a measuring platform and a micro-nano structure processing platform are integrated, a sample distance detecting device and the rotation matrix method are combined, the position data of four to-be-processed areas is obtained through the detecting device and substituted into a rotation matrix, then calculation is carried out to obtain the corrected micro-nano structure position data, the data is substituted into a processing system, and the laser spot center is accurately positioned on a sample. The method has the advantages that switching between different platforms is not required, the surface height data is measured to be directly input to a computer, the errors caused by slopes of a to-be-processed sample, a substrate and the surface of a three-dimensional movable platform are eliminated with the rotation matrix method, the position of the processed sample is accurately positioned, the to-be-processed sample is accurately arranged at the center of a laser spot, the accuracy of laser micro-nano processing is further improved, the accuracy of femtosecond laser processing can reach about 300 nm accordingly, and it is guaranteed that the actual obtained structure and the preset structure are same.

Description

technical field [0001] The invention relates to a method for femtosecond laser processing, in particular to a method for improving the precision of femtosecond laser processing. Background technique [0002] with CO 2 Laser, Nd:YAG laser and KrF 2 Compared with ultraviolet excimer laser, femtosecond laser direct writing micro-nano structure has small thermal effect, high precision and true three-dimensional processing capability. It is an ideal tool for the preparation of micro-nano optical devices and can be widely used in optofluidic chips, photonic crystals, Microcavity lasers and high-density optical storage and other fields. Femtosecond lasers can inject energy into highly spatially selective regions of a material within a time shorter than the thermal diffusion of the lattice. After focusing, the laser power density can be as high as 10 15 W / cm 2 , even if the material itself does not have intrinsic absorption at this wavelength, due to nonlinear processes such as...

AI Technical Summary

Problems solved by technology

In the actual processing process, the longitudinal length of the focused spot is only about 1 μm. In order to obtain the preset micro-nano structure, the longitudinal height error of the entire area to be processed must be less than 1 μm. When the length of the processing area is greater than 50 μm, the height difference caused by the inclination of the three-dimensional mobile platform, film and substrate is often greater than 1 μm, which will lead to a large difference between the actual processing result and the preset situation

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