tsv: via lining & filling [email protected]
TRANSCRIPT
TSV degree of difficulty
www.yole.fr, 2010
Basic via structure
Benfield
Process flow
Benfield
Profile & filling options
Profile & step coverage
Dielectric requirements
IEEE 2009 3D system integration conference
Resistance
Thickness (um)
Radius (um)
Resistivity (uOhmcm)
Calculated resistance (mOhm)
Poly-Si 100 10 1000 (BCl3) 3200
W 100 3 5.4 191
Cu (full) 100 W_bot =30W=60
2.65 2.1
Cu (hollow)
100 W_bot =30W=60
2.65 3.8
Why is thinning needed?• Step coverage of sputter?
– Maximum aspect ratio ~ 5– Tapering makes sure the seed is continuous– W_bottom=20um, t=650um wafer -> w = 134um -> pitch ~ 200um
• Pitch < 100– > wafer has to be thinned down
Silicon vias
Silex
Silicon vias
Silex
Epoxy-lining
Filling with sacrificial support
Packaging with TSV cap wafer
Wire bonding via metal
Via electrical results
Nickel wire magnetic assembly
Fischer, Roxhed:
Ni wire process flow
Fischer, Roxhed:
Solder filling
Copper ball filling
TSV filled by CNTs
CNT growth
