Year: 2009
Type: article
Abstract: Crank-shaped and Y-shaped through-hole interconnections (THIs) filled with Au-Sn solder are demonstrated in this study. They are expected to realize more high-density Wafer Level Package (WLP) of electrical devices including MEMS (Micro Electro-Mechanical Systems) and MOEMS (Micro Optical Electro-Mechanical Systems) fields, compared with conventional WLP using THIs consist of strait through-holes. In this paper, formation techniques of Crank-shaped and Y-shaped THIs are reported. In order to make Crank-shaped and Y-shaped through-holes in a substrate, both femtosecond laser irradiation and wet chemical etching are used. Crank-shaped through-holes, having 80 μm opening and laterally 600 μm sifted, are successfully formed in silica, PYREX and sapphire substrates. Y-shaped through-holes, 80 μm opening and 400 μm in deep, are also achieved. Gold(Au)-Tin(Sn) solder was filled into the holes by Molten Metal Suction Method (MMSM). Airtightness of the THIs was examined by Helium leakage test and estimated leakage rate was smaller than 1.0×10-9 Pa·m3/sec, which is enough to be used in the WLP applications.
Authors: Satoshi Yamamoto, Osamu Nukaga, Hiroyuki Wakioka, Tatsuo Suemasu, Hirokazu Hashimoto
Institution: Fujikura (Japan)
Language: English
Topic: 3D IC and TSV technologies
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W355241073