A research group led by Prof. CHEN Chilai from Hefei Institutes of Physical Science (HFIPS), Chinese Academy of Sciences (CAS), developed Through Glass Via (TGV) process for 3D advanced packaging, which realized low transmission loss and high vacuum wafer-level packaging of high-frequency chips and MEMS sensors.
3D packaging technology has been one of the main driving forces for developing integrated circuits. As an emerging vertical interconnection technology applied in wafer-level vacuum packaging, TGV, which has excellent electrical, thermal, and mechanical properties, realizes interconnection with the shortest distance and the minimum spacing between chips.
"We have overcome technical problems such as the manufacture of high-uniformity glass micropore arrays, glass dense reflow, and high-density filling of glass micropores and metals," said Dr. LI Shan, who conducted the research.
In this research, the team proposed a new TGV wafer manufacturing scheme. The newly-developed TGV wafers boasted high uniformity, high density and high aspect ratio, which enabled the ultra-low leakage rate and ultra-low signal loss. After testing they found that some parameters are even better than international standards.
"They can be applied to 5G/6G high-frequency chips such as ring resonators, waveguide slot antennas, and millimeter-wave antennas, as well as new 3D packaging requirements for MEMS gyroscopes and accelerometers." said Dr. LI Shan, "and we can make different size according to requirements."
Related technologies have been supported by projects from the National Natural Science Foundation of China, the Ministry of Science and Technology, the Chinese Academy of Sciences, and Anhui Province.
Figure 1: Conductive metal-based TGV wafers. (customized size as 4, 6, 8 inches) (Image by LI Shan)
Figure 2: Conductive silicon-based TGV wafers. (customized size as 4, 6 inches) (Image by LI Shan)