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Author Kim, Jung Mo ♦ Jung, Jae Pil ♦ Zhou, Y. rman ♦ Kim, Jong Young
Source SpringerLink
Content type Text
Publisher Springer US
File Format PDF
Copyright Year ©2007
Language English
Subject Domain (in DDC) Natural sciences & mathematics ♦ Chemistry & allied sciences
Subject Keyword Ultrasonic bonding ♦ lead free solder ♦ Sn-3.5wt.%Ag ♦ joint reliability ♦ intermetallic compound ♦ Solid State Physics and Spectroscopy ♦ Electronics and Microelectronics, Instrumentation ♦ Characterization and Evaluation of Materials ♦ Optical and Electronic Materials
Abstract Ultrasonic bonding of Si-dice to type FR-4 printed circuit boards (PCB) with Sn-3.5wt.%Ag solder at ambient temperature was investigated. The under-bump metallization (UBM) on the Si-dice comprised Cu/Ni/Al from top to bottom with thicknesses of 0.4 μm, 0.4 μm, and 0.3 μm, respectively. The pads on the PCBs consisted of Au/Ni/Cu with thicknesses of 0.05/5/18 μm, sequentially from top to bottom. Solder was supplied as Sn-3.5wt.%Ag foil rolled to 100 μm thickness, and inserted in the joints. The ultrasonic bonding time was varied from 0.5 s to 3.0 s, and the ultrasonic power was 1400 W. The experimental results showed that reliable joints could be produced between the Si-dice and the PCBs with Sn-3.5wt.%Ag solder. The joint breaking force of “Si-die/solder/FR-4” increased with bonding times up to 2.5 s with a maximum value of 65 N. A bonding time of 3.0 s proved to be excessive, and resulted in cracks along the intermetallic compound between the UBM and solder, which caused a decrease in the bond strength. The intermetallic compound produced by ultrasonic bonding between the UBM and solder was confirmed to be (Cu, Ni)$_{6}$Sn$_{5}$.
ISSN 03615235
Age Range 18 to 22 years ♦ above 22 year
Educational Use Research
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2007-11-17
Publisher Place Boston
e-ISSN 1543186X
Journal Journal of Electronic Materials
Volume Number 37
Issue Number 3
Page Count 7
Starting Page 324
Ending Page 330


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Source: SpringerLink