Thermally induced IC package cracking

Three methods which have demonstrated improved resistance to plastic package cracking are discussed. One is the elimination of the die paddle through the use of tape automated bonding (TAB)-type tape. The second method is the use of lead frame surface treatments prior to encapsulation to eliminate the moisture concentration at the back-side of the die paddle. The third method is the simple elimination of package moisture by baking the components just before the mass reflow operations. Each of these methods has separate advantages and disadvantages which are detailed and examined in terms of the overall manufacturability of the components. The problems encountered when trying to sidestep the thermal cracking problem by the use of sockets is discussed. Ceramic packages also suffer thermally induced cracks, including pin grid array packages which only experience the relatively mild thermal exposure of standard wave soldering. The parameters involved in this phenomenon are detailed