FCS Parylene-AF4 Conformal Coating as a Buffer Layer in TGV

Intel patent announced that a stress buffer layer is between the conductive layer and the TGV sidewall

Why Parylene-AF4 can be used as a buffer layer for TGV ?

(1) Low Elastic modulus (4~5Gpa) polymer film: Relieve stress at the glass/metal interfaces (<10Gpa).

(2) High aspect ratio (50:1) conformal coating: Uniform coating on TGV through-hole structure.

(3) Molecular-level thin film process: Filling in notches, cracks, and/or crevices on the surface of the glass core.

(4) High temperature resistant(350°C)polymer property: Passed TGV metallization annealing (300°C) & thermal cycling reliability.

 

 

SEM cross-section observation that the step coverage of Paryleme-AF4 film in the TGV deep hole

(1) 8” TGV glass wafer, φ50mm/Depth 450mm/Pitch200µm(hole to hole), aspect ratio AR=1:9

(2) Parylene-AF4 conformal coating is used as a buffer layer in TGV deep holes, uniform film thickness (800nm~900nm) on TGV through-hole structure.