Wetting interactions between the Ni-Cu-P deposit and In-Sn solders

The interactions during wetting between an electroless Ni-Cu-P deposit and molten InSn solders were investigated with the aid of scanning electron microscope (SEM), X-ray diffractometer (XRD), and Auger electron spectroscope (AES). The intermetallics In/sub 3/Ni/sub 2/ and In/sub 27/Ni/sub 10/ were formed at the interlayer for the Ni-Cu-P with 51In-49Sn and 80In-20Sn systems, in the temperature range of 250-300/spl deg/C. In addition to these two intermetallic compounds Ni/sub 3/Sn/sub 4/ was also formed with the 20In-80Sn system. The Ni/sub 3/Sn/sub 4/ dissipates gradually with increasing temperature. A two-stage wetting mechanism was disclosed for the wetting of Ni-Cu-P deposit with the InSn solders in the temperature range of 250-325/spl deg/C.