Challenges & Solutions of Cu Wire Bonding on DFN Package with Low Modulus LeadFrame Tape

The Dual Flat Non-leaded (DFN) package is being widely used in the semiconductor industry. In order to achieve good output responses, such as (1) good wire bondability, (2) no mold flash , and (3) no tape residue after tape removal, requires a good Lead Frame (LF) Tape which could provide a good support during Wire Bonding (WB).As known Copper (Cu) wire has become the mainstream choice in WB due to its low price and yet can achieve excellent electrical performance. However, Cu wire is harder and stiffer than Au wire. Cu wire bonding, especially in stitch bonding, has greater challenges in process optimization, as it has a narrower process parameter window compared with Au Wire. Thus, this paper is going to share the challenges and solution in getting the optimum WB parameter using the Low Modulus LF Tape. Also discussed about interaction between different LF tapes and WB performance, and monitor for other defect such as tape residue. Optimum WB process parameter was studied to ensure good stitch bond with high pull strength, good Cu remain using Low Modulus LF Tape.