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Project Portfolio.pdf


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3
Wafer Adhesion Strength Innovation
Summer Intern Project 2/2
Purpose: Evaluate and characterize adhesion strength of singulated chips with
silicon nitride and tantalum backing off of a silicon wafer
Problem:
 Removal of die from the wafer results
in 3-5% failure due to chip cracking
 Die removal machine had no
capability to measure removal force,
was very difficult to access for tooling
and was in an active manufacturing
line
 Silicon nitride wafers cause print
head failures due to particulate
matter so tantalum backed wafers
are preferred
 The adhesion characteristics for
silicon nitride vs tantalum needed to
be understood to mitigate chip
cracking when the switch is made
Solution: Pixel Density Analysis
• Allows for dies adhesion to be
measured while still attached
• Example shows 67% no
adhesion (light blue) 21%
adhesion (dark blue) and 12%
for the nozzle slots
• Roughly 76% adhesive removed
and 24% of adhesion remains
for the given sample
• No force values for die release
but a comparison based on
adhesion percent removed was
made
• Automated
pixel
density
analysis with a script

Wafer with defective chips leftover for testing