Pressure resistance of photoresist and substrate in contact lithography

The tight contact of the mask and the substrate is essential in contact lithography for reducing unnecessary diffraction and improving the resolution. This enables contact lithography to reach sub-micrometer resolution and thus shows a great prospect of fabricating arrayed sub-micrometer structure. However, the direct contact of the mask and the substrate and the pressure between the mask and the substrate may lead to the deformation of the photoresist film or the substrate, and affect the micro-structure on the photoresist layer. Therefore, it is necessary to verify whether the change of the pattern size of micro-structure caused by the deformation of the photoresist film and substrate is within the allowable error range. <br/> <br/> This paper takes the silicon wafer spin-coated with S1805 photoresist as the research object, and conducts static pressure experiments and interference exposure experiments. Within a pressure of 300 kPa, there is little variation in the thickness of the photoresist film, and it has no significant effect on the pattern size on the photoresist layer. The result shows that when fabricating arrayed sub-micrometer structures, the change of the pattern size of micro-structure is within the allowable error range. Therefore, this paper demonstrates the theoretical feasibility of contact lithography with the pressure in the fabrication of arrayed sub-micrometer structures.