Application of Simulation to Enhance Complex Clipbond Package Mold Tools

In the era of electrification and automatization, semiconductor chipmakers constantly evolve to produce a performance-edge-over package in several respects: Higher operating temperature and voltage. To enable such requirements, automotive electronic designers must consider delamination robust packaging solution to support the die technology. In this paper, 2 case studies at molding process are used to prove fast and high accuracy method to achieve first time right mold tool design that worked in equilibrium with process, material and leadframe design. The aim of this paper is to prove the use of simulation method to support tool designing during initial risk assessment input, considering that resolving moldability problems is a time intensive process. This paper outlines a systematic approach using simulation to predict risk and improves design for new mold tools. The first case study is on Clip Flat Power package (CFP) with 2 sided package body that has been encountering incomplete fill on die types smaller than 1mm2 size. By using short shot analysis data that indicates unbalanced mold flow between top and bottom package, the mechanism of flow has generated idea to investigate the ideal opening, depth, location of gate with respect to package construction. With the computer aided simulation, proof of concept (PoC) is executed. The 3 factors were varied and filling percentage is used as output response to gauge performance of various legs. The study showed location of the gate is a key factor to achieve balanced flow, hence the ideal position of the gate is predicted. The actual tool able to eliminate incomplete fill on packages with die smaller than 1mm2 size. The study also proved that 2 sided package body with clip interconnects need to achieve minimal difference between top & bottom mold flow to prevent incomplete fill phenomena. The second case study is on small outline CFP with open heatsink where molded units in strip form can trigger delamination at time 0 due to poor precision degating process. Poor punching mechanism can lead to package delamination. Simulation model of molded strip is subjected to various factors; 1) Precision degate tool (PDT) to package body distance, 2) Precision degate tool design. The study shows angular punch tool is most effective factor among all others and able to reduce delamination. Further study is to explore construction of predictive model that can estimate risk of heatsink flash on open heatsink CFPs using high fluidity EMC. The objective is to promote application of simulation on tool, design for manufacturability and enable faster time to market.