Holographic Double-Sided Photolithography Based on Improved Gerchberg-Saxton Algorithm

Given the problems of cumbersome steps and low effectiveness of the present double- sided microdevice processing technique, a holographic double- sided photolithography based on the enhanced Gerchberg- Saxton (GS) algorithm is proposed, which employs a single light source to achieve a double-sided pattern produced by single exposure on the upper and lower surfaces of the glass substrate. This approach realizes double-sided pattern reproduction in the target space by determining the combined holograms corresponding to various axial position patterns and loading them onto a spatial light modulator (LCOS- SLM) to regulate the incident light field. The holographic reconstruction of patterns A and B at distances of 2 mm and 4. 06 mm from the focal plane, respectively, is calculated and simulated using the modified GS method. The experimental device was set up to achieve the simultaneous exposure of the upper and lower surfaces of the 3-mm thick transparent quartz glass substrate, and the problems of speckle, stray light, and crosstalk in the process of light field generation were examined and solutions were proposed, and finally 60- mu m linewidth double-layer pattern exposure was realized, which confirm the feasibility of the proposed method for double-sided lithography. A single hologram and a single light source are used in the technique described in this research to create numerous layers of arbitrary images in the target volume during a single exposure, considerably simplifying the processes involved in producing double-sided pictures.