一引言功率晶体管大致被分为使用金属管壳的金属封装和使用硅酮或环氧树脂的塑料封装两种形式。不言而喻,促进从金属封装向塑料封装过渡的主要因素是:塑料封装可以降低功率晶体管的成本,使其小型化,并减轻重量;而阻碍这个过渡的主要因素则是除可靠性不够外,在绝缘和散热上也有困难。但是,近年来已经研制出性能优良的树脂,从某些方面看,塑料封装已经可以同金属封装相媲美。不久的将来塑料封装会变得和金属封装一样可靠,而且有可能超过它。 I. INTRODUCTION Power transistors are roughly classified into metal packages using metal packages and plastic packages using either silicone or epoxy. It goes without saying that the main factors driving the transition from metal packages to plastic packages are that plastic packages reduce the cost of power transistors, miniaturize them, and reduce weight; the main impediment to this transition is the lack of reliability There are also difficulties in insulation and heat dissipation. However, in recent years, resins having excellent properties have been developed. In some aspects, plastic packages are already comparable to metal packages. In the near future, plastic packages will become as reliable as metal packages and potentially exceed it.