关键词: 基板封装, 芯片断裂, 注塑压力, 有限元分析, 阻焊层

Abstract: In the molding process of laminate substrate-based package assembly, the die has risk of crack. The package model is built by finite element method, apply mold pressure loads and constraints, and calculate the stress of die under mold pressure. It is found that the main reason of the die stress is that the area with bottom solder mask openings will sag under mold pressure. Thicker substrate, thicker die, thinner solder mask thickness and smaller mold pressure can reduce die stress obviously. In addition, the relative position between chip and openings of back solder mask is also one of the main factors. Relative to the back solder mask openings, overhang ratio of die should not be excessive, and it’s better to choose the short side of die to hang out, avoid long side to hang out, and the overall hanging of die can also help reduce the stress of die.

Key words: laminatesubstrate-basedpackage, diecrack, moldpressure, finiteelementanalysis, soldermask