Multilayer Uniform Photoresist Coating on Silicon Wafers via Spin-Coupled Inkjet Printing

A spin-coupled inkjet coating process is proposed for multilayer photoresist film on silicon wafers. An interlacing coating mode is introduced in order to tackle the film defects at the splicing area of multiple printheads. The deposition model with droplet flow is employed to reveal the mechanism of multilayer photoresist film formation. Besides, the effects of printhead movement velocity and wafer rotational speed on photoresist film formation are quantitatively explored through the in-house inkjet coating prototype. Results show that the optimal photoresist film evenness index can achieve 4.51% with a thickness of $1.562~\mu $ m at the rotational speed of 12 r/min. With superior film uniformity and higher coating efficiency with multiple printheads, spin-coupled inkjet coating offers a viable process for multilayer uniform film formation on large-size silicon wafers.