PBGA(Plastic Ball Grid Array) is composed of some materials such as PCB(Printed Circuit Board), epoxy molding compound, die attach and so on. Reliability of PBGA package is weak compared with plastic packages. The weak points of reliability are the lower resistance to popcorn cracking, which is induced by moisture absorption in PCB, and the pressure cooker test corrosion, which is the basic problem due to the material characteristics of PCB. Introducing the PCB banking and the plasma treatment cleared the popcorn cracking phenomenon. The PCB banking and plasma treatment reduced the epoxy void by eliminating the source of moisture vaporization during the epoxy curing and enhanced the adhesion between PCB and epoxy. Also, plasma treatment enhanced the wettability of epoxy on PCB. The problem of corrosion is cleared using multi-functional epoxy. This type of EMC(Epoxy Molding Compound) is recommended in package using PCB as a substrate.