イオンエッチングによる微細パターン形成

抄録

Ion-beam etched pattern profiles for several kinds of substrate materials have been investigated, using a Kaufman type ion source at an accelerating voltage of 500 V and a current density of 0.5 mA/cm². A photoresist stripe pattern with a 2.5 μm width is used as an etching mask. SEM observation of etched substrate surfaces reveals that the substrate pattern profile can be characterized by pattern edge angle, pattern width difference between substrate and mask, and wall height of redeposition. These values depend not only on resist thickness or etching time but also on the substrate materials. The dependence of pattern profiles on substrate materials results from the change in the resist etching rate at pattern edge due to the redeposition effect of substrate materials. The effect can be interpreted by analyzing a simple model. The analysis leads to the determination of the optimum resist thickness for high resolution pattern fabrications.