Addressing Tape Delamination on Complex QFN through Tape Supplier Collaboration

Very thin Fine Pitch Dual Flat Package No Leads (VFDFPN) is an IC used smartphones or displays. STMicroelectronics (ST) manufactures this device in Calamba on an existing Quad Flat No lead (QFN) line. VFDFPN12 leads is one of its sub-packages introduced having a thicker wire diameter of 33um against normal wire of 20um requiring higher bond force. Also the bonding layout requires several leads with triple stitch bonding resulting to higher pressure applied on lead causing the tape to delaminate from the lead. After mold this results to moldflash and tape residue specific to the affected leads. This technical paper will cover all engineering efforts collectively done starting with the most effective containment to the best cost effective solution available. Understanding the phenomenon of tape delamination with respect to wirebond process and material was clearly defined. With the collaboration of our leadframe tape supplier, we co-develop a tape which can withstand underlying factors and end up with a product with no moldflash and tape residue