J161022 中性粒子ビームエッチング装置によるプラズマダメージ回復効果の8インチ面内分布

抄録

When the plasma process conduct to manufacture a semiconductor device, that is caused the electrical/mechanical degradation on the surface, called "plasma damage", especially as a device dimension shrinks. Charged ions and vacuum ultra violet (VUV) rays in a plasma source yield the damage. Neutral Beam Etching (NBE), in which neutralized species with kinetic energy bombardment on a surface and promotes vertical but damage-free etching, is a very attractive technique for MEMS fabrication. To evaluate the effect of surface damage on mechanical properties quantitatively, we focused on Q-factor of micro-cantilever. This value of a cantilever is affected by several energy-loss mechanisms, such as support loss, thermo-elastic damping loss, and surface loss. Theoretically, when a cantilever is thin Q factor is the most sensitive to surface loss. Here, δEds is a surface condition parameter, which is related to the amplitude of surface loss. Therefore, we compare the surface condition using δEds. From a production viewpoint, it is important to examine the uniformity of damage-removal characteristics in an 8-inch NBE equipment. The surface property of a cantilever as a function of etched depth was measured. The etching rate is a nominal value measured at 9 point. After the etching by 100 nm, δEds value almost converged to 0.5, indicating uniform etching and damage-removal characteristics by NBE over an 8-inch wafer.