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Author Kim, Joong Do
Source SpringerLink
Content type Text
Publisher Springer-Verlag
File Format PDF
Copyright Year ©2006
Language English
Subject Domain (in DDC) Natural sciences & mathematics ♦ Chemistry & allied sciences
Subject Keyword Wafer bumping ♦ electroless nickel/gold bump ♦ flip-chip-type CMOS image-sensor package ♦ Optical and Electronic Materials ♦ Characterization and Evaluation of Materials ♦ Electronics and Microelectronics, Instrumentation ♦ Solid State Physics and Spectroscopy
Abstract Wafer bumping technology using electroless nickel bump with a thin gold layer was studied for the flip-chip-type CMOS image-sensor (CIS) package for mobile-phone camera modules. The precise control of process parameters in the electroless nickel solution was undertaken by synthetic consideration of the effects of solution temperature, pH, stabilizer concentration, and aluminum pad size on the electroless nickel/gold bump formation. The flip-chip bonding process fitting the electroless nickel/gold bump is conducted by optimization of bonding temperature, pressure, and time. Reliability tests are performed to ensure the robustness of the image-sensor module. The impurity particle density is estimated to be one per 300,000 pixels by 3D laser analysis on the image-sensor surface. The phenomenon of the drop in chip yield during the wet process is attributed to the organic particles produced during the wafer backside coating. From all the experimental results, we first suggest that electroless nickel/gold can be applied to flip-chip-type CIS package for the mobilephone camera module without any significant impurity contamination of the image-sensor surface.
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 2006-01-01
Publisher Place New York
e-ISSN 1543186X
Journal Journal of Electronic Materials
Volume Number 35
Issue Number 2
Page Count 6
Starting Page 273
Ending Page 278


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Source: SpringerLink