2.7 The Under Bump Metal and Underfill.pdf

Semiconductor Process

1. 2D Packaging & Assembly
Packaging Process ​
2.7 Under Bump Metal and
Underfill

2. 2D Packaging & Assembly
Under Bump Metallisation
•Protection of Al Pad on Die
•Provide platform for solder
wetting
•Adhesion layer to Al bond pad
•Cu, Al, Ti
•Diffusion layer
•Ni, Cu
•Wetting layer
•Sn, Ag
•Layers deposited
•Electroplating or sputtering
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3. 2D Packaging & Assembly
Capillary Underfill Process
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