NiAl合金のクラック生成に及ぼすB添加の効果

抄録

Sputtered Al/Ni multilayer film shows self-propagating explosive reaction, which enables us to use the film as a local heat source for instantaneous reactive bonding for semiconductor devices. However, cracks are introduced into reactively alloyed NiAl layer due to its volume shrinkage after the reaction, which decreases the mechanical reliability of the bonded element. In this study, we investigate the B addition effect on Al/Ni multilayers to reduce cracks for reliable die bonding. The cantilever bending test and tensile fracture toughness test are conducted to examine the Young’s modulus, yield strength, tensile strength, and fracture toughness of the reactively NiAl with and without B. The B-NiAl film’s fracture toughness value is 2.82 MPa·m1/2, which is 1.39 times higher than the value for the NiAl without B. Transmission electron microscopy suggests that B segregation at the triple point of crystal grains suppresses the intergranular fracture, which has contributed to improve its toughness.