Process Controls For Advanced Thermocompression Bonding
Author: Tom Strothmann Company: Kulicke & Soffa Industries, Inc. Date Published: 10/18/2016
IWLPC (Wafer-Level Packaging)
Abstract: Thermocompression bonding is a unique process in semiconductor manufacturing since it essentially bridges the manufacturing space between front end semiconductor processes and back end of line packaging. The amount of potential data generated from a TCB process is enormous and the opportunities for process monitoring and control are significant. In a conventional mass reflow process temperature and oxygen levels can be tracked and periodic monitors can be run through the oven to verify profiles, but process data for individual die is not available. In a local reflow TCB process there is full material tracking back to the source wafer with die alignment, temperature, force, time to melt, stack layer position, and placement position logged for each die processed. Excursions in the process can be detected quickly and with the proper process controls, measures can be implemented to contain potential risk. In high reliability applications data logging and traceability is available for each die bonded, but this data is also generated for all standard commercial applications. Thermocompression bonding is perceived as a back end assembly process but the level of process control can be similar to that used in front end semiconductor manufacturing. This paper will review methods available for process control in advanced TCB processes suitable for single die, 2.5D and 3D packages.
Thermocompression Bonding, TCB, Process Control, APC.