Low alkaline solution to deposit electroless Ni-Zn-P film on Al pad
The amorphous electroless NiP film is used as underbump metallization (UBM) structure of chip pad or surface finish of IC substrate (or printed circuit board) to join with different solders on microelectronics package due to low cost process, low IMC growth rate, and good solder wetting behavior. However, Au film usually induced some problems on Au/NiP films, including Au corrosion, black pad issue on Ni-P pad, Au delamination and Au embrittlement when the process step of Au film was out of control. There is another ternary electroless nickel alloys Ni-Zn-P film, which is considered as a barrier film on a galvanic Zn or Ni-Zn sacrificial layer in a multi-component corrosion protective coating on steel. Specific properties of electroless Ni-Zn-P film were reported, especially in electrochemical corrosion tests. However, little study is stressed on the formation Ni-Zn P film under low alkaline. In this study, four kinds of ternary Ni-Zn-P films (Ni-5Zn-13P, Ni-4Zn-7P, Ni-8Zn-8P, and Ni 7Zn-10P) were deposited on sputtered Al film in alkaline electroless solution at a pH value of 8.5 controlled by NH4OH addition. The electroless Ni-8Zn-8P film consisted of typical nodule surface and was free from crack. The interfacial morphology and wetting angle of the Sn-3Ag-0.5Cu/Ni-8Zn 8P joint showed the good wetting behavior. The (Ni,Cu)3Sn4 intermetallic compound can attach well onto the Ni-8Zn-8P film after reflow. The line profile of Zn element showed that the Zn only distributed within the Ni-8Zn-8P film, indicating that Zn cant migrate to form (Ni,Cu,Zn)3Sn4 IMC, in which no Zn was traced. This study demonstrates that the ternary Ni Zn-P film might be a potential alternative for under-bump metallization (UBM) application.
Ni-Zn-P electroless UBM
Fong-Cheng Tai Hsiu-Min Lin Jenq-Gong Duh Liang-liang Li
Department of Materials Science and Engineering, Tsing Hua University, Hsinchu, Taiwan, China Department of Materials Science and Engineering, Key Lab of Advanced Materials, Tsinghua University,
国际会议
西安
英文
429-432
2010-08-16（万方平台首次上网日期，不代表论文的发表时间）