Slit structure as a countermeasure for the thermal deformation of a metal mask

A metal mask used for the pattern formation of sputtered films is sometimes deformed during film deposition, because its temperature increases during deposition. In this study, a slit structure as a countermeasure for the deformation is proposed. The mask investigated is made of 0.3-mm-thick stainless steel and is composed of a frame with many beams running inside the frame. The slits in the structure absorb the thermal expansion of the beams, which results in the relaxation of thermal stress in the beams. The relaxation of the stress is analyzed using the finite element method as well as the theory of beam bending. It was experimentally confirmed that a mask furnished with well-designed slits was not deformed.