Mathematical analysis of soft baking in photolithography

Jyh-Ping Hsu, Sung-Hwa Lin, Wen-Chang Chen, Shiojenn Tseng
2001 Journal of Applied Physics  
The soft baking step of a photolithography process is analyzed theoretically, taking the effect of the temperature dependence of the diffusivity of solvent into account. A coordinates-transform technique is chosen to solve the moving boundary problem under consideration. The temporal variation of the thickness of a film is predicted, and the result obtained justified by fitting experimental data reported in the literature for both poly͑methylmethacrylate͒ film and Shipley UVIII photoresist. We
more » ... II photoresist. We show that, depending upon the types of photoresist film and the operating conditions, the transport of solvent may be controlled by the diffusion of solvent in a film or the convective transport of solvent from the gas-film interface to the bulk gas phase.
doi:10.1063/1.1335823 fatcat:lowqkgpdobbslnkxi4t4vpdxwu