Ultra-high selectivity TSV etching hardmask process development and integration for 3D-SIC

Through Silicon Via (TSV) technology is an attractive solution for image sensor, MEMS devices, 3D stacking and others. TSV formation is one of the key processes for three dimensional stacked integrated circuit (3D-SIC). Fabrication of high aspect ratio TSV by using different hard masks such as photoresist, SiO
₂
and SAP100 has been discussed in this paper. Selectivity of hard masks was also presented. 2 μm diameter TSV with aspect ratio higher than 10 are etched on 200 mm wafer using deep reactive ion etching (DRIE) process. SAP100 hard mask (500Å to 700Å) was evaluated. Ultra high selectivity which is >;10,000 with respect to Si has been achieved.