| In the 21 st century,China ’s manufacturing industry has developed rapidly,from the original low-end to high-quality,high-precision manufacturing.In order to achieve a breakthrough in China ’s manufacturing industry,the establishment of a high-precision measurement system is a key link.In the precision measurement system,the grating displacement sensor is widely used.As the measurement accuracy tends to be high precision and large range,higher requirements are placed on the manufacturing accuracy of the grating.The ruling error is an important factor affecting the manufacturing accuracy of the grating ruler.Reducing the ruling error can effectively improve the grating manufacturing accuracy.China still has certain disadvantages in manufacturing high-precision gratings.In recent years,with the development of semiconductors,the performance of lithography technology has also been improved,and components with smaller and smaller feature sizes can be fabricated.Lithography technology is a kind of processing technology that can accurately transfer the pattern information of the prefabricated mask to the surface of the pre-coated silicon wafer through the exposure system.It can be used in the processing of micro-optical components with high efficiency,low cost and simple processing technology.Therefore,this paper intends to fabricate gratings by lithography.As the core component of lithography,projection lens directly affects the quality of image transmission.In-depth study of the imaging theory,found that distortion is an important parameter affecting the ruling error.Subsequently,by selecting reasonable optical structure,initial structure and parameters,the distortion is effectively corrected and the overall aberration meets the lithography requirements.At the same time,in order to pursue a large exposure area,the field of view of the lithography objective is required.Through the optimization analysis in the optical software,a lithography projection lens with a small number of lenses,low tolerance requirements and small scribing error is finally obtained.Then,the influence of the tilt and eccentricity error of the lithography lens on the ruling error is studied,and the accuracy is designed.Finally,the simulation analysis is carried out in the non-sequence to verify the rationality of the projection lens structure and error distribution.It is feasible to manufacture high-precision gratings by lithography technology.The theory and method of this lens design can provide reference for the subsequent improvement of grating manufacturing accuracy. |
