Interfacial reactions of Ag alloy wires with wire bonded pads for IC and LED packages

• Main Authors: Che-Cheng Chang, 張哲誠
• Other Authors: 莊東漢
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/ex7s83

博士 === 國立臺灣大學 === 材料科學與工程學研究所 === 101 === Abstract Electronic packaging industry wire bonding technology in the first stage of diameter 20μm level package, in the past most of the major is to use as an Au wire bonding material. With Au Price from less than $ 300 per ounce in 2001, growing to 2011 reached one ounce more than 1800 U.S. dollars,the future will be more improved manufacturing costs.In addition to raw material cost factor, Au wire and Al pad prone to excessive intermetallic compound (IMC) cause joint reliability decreases.In this study, the price is only one third of the Au wire Ag alloy wire, diameter 20μm level and Al pad on a variety of reliability testing (HTS TCT PCT). The present study found that because of the hardness of Ag alloy wire with Au wire similar, so there is no like Pd-coated Cu wire will damage Al pad causing the problem of poor bonding strength, Ag alloy wire and Al pad bonding interface is very complete. And make more use of the thermal aging test temperature 100 ℃ to 200 ℃; aging time 0hr to 1000hr for bond strength test and interfacial reactions observed. Use dage 4000 made the first solder ball shear test and then observed through an electron microscope can obviously find Ag alloy wire and Al pad bonding interface is very close, so the test results are broken inside the wire; while the Pd-coated Cu wire the Al pad intermetallic compound produced (IMC) is thin, the bonding strength is not high. Via the 200 ℃ 1000hr thermal aging tests can be found, Au wire bonding strength with the Al pad thickness because of excessive intermetallic compound (IMC) cause embrittlement and produce large amounts of the contact holes caused by the contact strength decreases; while Ag alloy wire and Al pad is because the generated intermetallic compound (IMC) growth is moderate, even at 200 ℃ 1000hr the timeliness, the bonding strength is still high. Using the Ag alloy wire in addition to reducing costs, by the experimental study Ag alloy wire after the heat aging and the Al pad is much stronger than the bonding strength test of Au wire bonding strength with the Al pad, since Ag alloy wire and Al pad has a special medium the interfacial reaction mechanism.