Study of Glue Creeping Behavior On Die Surface for Thin Die Using Roughen Pre-plated Leadframe

Many Dual Row Quad Flat No Lead (DRQFN) Radio Frequency (RF) semiconductor packages today require thin die to achieve better RF performance. This has posed a challenge for die attach glue creeping onto die surface which can cause wirebond-ability issue. The situation is even more challenging when Anti-Epoxy Bleed Out (Anti-EBO) is being applied on roughen pre-plated (RT-PPF) lead frame, where the epoxy bleed out to the lead frame side is being mitigated but has worsened the glue creeping onto die surface. Although this problem can be minimized by selecting non-roughen lead frame surface, but it will create high risk for package delamination, causing the product to be unable to meet the stringent package reliability requirement. In this paper, a comprehensive study was conducted including glue material behavior prior to oven curing, the staging time window control between die attach and oven cure process, and snap cure prior to oven cure. The result of the study showed that snap cure is able to partially cure the glue and freeze the resin bleed-out, which allowed longer staging time for more production flexibility, hence enabling higher manufacturability and process robustness for DRQFN with thin die on Anti-EBO lead frame.