Keng Yuen, J. A., Chong, S. C., Daniel, I. C. (2023, December 5). Development of Chip to Wafer Assembly with CuSnAg Microbump on Solder on Pad Interposer using Thermocompression and Solder Reflow. 2023 IEEE 25th Electronics Packaging Technology Conference (EPTC). https://doi.org/10.1109/eptc59621.2023.10457893
Abstract:
Chip to wafer (C2W) bonding to form interconnect is not
new to the industry. However, if the bottom wafer has thick (i,e 2 1Oum) Cu RDL layers, the CTE
difference between Cu RDL and silicon material of the bottom wafer creates tremendous warpage
during any heating or solder reflow process. Post flip chip bonding, this warpage causes cold
joints and lead to device electrical failure. We had demonstrated good solder joint
connection using thermocompression process with 5Oum top chip to 775um bottom wafer. The bottom
wafer has 3 layers of Cu RDL (each layer is 4um in thickness) and tin silver solder on pads. A
detail comparison using thermo- compression and solder
reflow process to perform C2W will be explored.
License type:
Publisher Copyright
Funding Info:
This research / project is supported by the A*STAR - Centre of Excellence in Advanced Packaging 3.0
Grant Reference no. : I2101E0008