非晶質薄膜を介した銅と封止樹脂の接合

抄録

With the increase in the power density of power modules for hybrid vehicles, the resin-molded components have recently been required to operate at high temperatures, which could cause the delamination of the resin layer from the copper (Cu) substrate because of their different thermal expansion behavior. Generally, nickel–phosphorus (Ni-P) plating is applied to the Cu substrate and primer pretreatment is performed prior to resin molding to enhance the adhesion strength between the resin and Cu substrate. However, the use of a primer has several disadvantages such as increasing the cost and complexity of the manufacturing process. To decrease the number of process steps, we changed the film plated on the Cu substrate from Ni-P to a carbon–hydrogen–silicon (C-H-Si) amorphous material prepared using a plasma-enhanced chemical vapor deposition (CVD) method. A resin–Cu bonded specimen was then prepared by forming epoxy-based resin on the C-H-Si-coated Cu substrate. The adhesion properties of the specimen were evaluated by conducting a shear bonding test. The test results indicated that the specimen maintained a high interface strength of 30 MPa even after heating at 473 K for 1000 h. Such a high bonding strength seems to be derived from both physical and chemical factors. One is an anchor effect originating from the nanosized morphology on the film surface. The other was the good chemical affinity between the resin and film. The film contained CHX groups, which would have good wettability for the CHX groups in the resin, and hydroxyl groups, which would form hydrogen bonds with hydroxyl groups in the resin.