습식공정으로 thermal via용 SI 관통 via를 형성하기 위해 TMAH 용액의 농도와 온도에 따른 Si 기판의 이방성 습식식각 거동을 분석하였다. TMAH 용액의 온도를 $80^{circ}C$로 유지한 경우, 5 wt%, 10 wt% 및 25 wt% 농도의 TMAH 용액은 각기 $0.76{mu}m/min$, $0.75{mu}m/min$ 및 $0.30{mu}m/min$의 Si 식각속도를 나타내었다. 10 wt% TMAH 용액의 온도를 $20^{circ}C$와 $50^{circ}C$로 유지시에는 각기 $0.07{mu}m/min$와 $0.23{mu}m/min$으로 식각속도가 저하하였다. Si 기판의 양면에 동일한 형태의 식각 패턴을 형성하여 $80^{circ}C$의 10 wt% TMAH 용액에 장입하고 5시간 식각하여 깊이 $500{mu}m$의 관통 via hole을 형성하였다.
In order to fabricate through-Si-vias for thermal vias by using wet etching process, anisotropic etching behavior of Si substrate was investigated as functions of concentration and temperature of TMAH solution in this study. The etching rate of 5 wt%, 10 wt%, and 25 wt% TMAH solutions, of which temperature was maintained at $80^{circ}C$, was $0.76{mu}m/min$, $0.75{mu}m/min$, and $0.30{mu}m/min$, respectively. With changing the temperature of 10 wt% TMAH solution to $20^{circ}C$ and $50^{circ}C$, the etching rate was reduced to $0.067{mu}m/min$ and $0.233{mu}m/min$, respectively. Through-Si-vias of $500{mu}m$-depth could be fabricated by etching a Si substrate for 5 hours in 10 wt% TMAH solution at $80^{circ}C$ after forming same via-pattern on each side of the Si substrate.
