Patent ID: 7452568

Claim:
A process for filling via openings on a substrate comprising: providing a substrate having via openings defined on a via-surface; providing at least a layer of a fluid particulate suspension on said via-surface; centrifuging said substrate: wherein said centrifugation is performed with a swinging-bucket rotor; wherein said fluid particulate suspension comprises: a suspension fluid; and a plurality of particles; wherein said suspension fluid is a reactive fluid comprising a curable liquid resin and a dispersing agent; wherein said curable liquid resin comprises polynorbornenes; wherein said dispersing agent comprises naphthalene sulfonic acid condensates; wherein said plurality of particles is selected from cores coated with metals; wherein a first portion of said cores is coated with a first solder-forming metal; a second portion of said cores is coated with a solder-forming metal complementary to said first metal; and wherein said cores comprise a ceramic having a negative volumetric coefficient of thermal expansion; wherein said ceramic is beta-eucryptite; and wherein said substrate is electrically biased relative to said fluid particulate suspension; brushing said via-surface during centrifugation; vibrating said substrate during centrifugation; creating a vacuum in a centrifuge chamber; spraying a fluid particulate suspension against said via-surface; curing said reactive fluid thereby forming a substantially solid mass in said via; providing a brush means; wiping excess particles from said via-surface using said brush means; wherein said brush means comprises doctor blades; providing a filler-mask having through-via defined herein, said filler-mask having a via-surface disposed to contact said fluid suspension and a substrate-contact surface disposed to contact said substrate via-surface; and aligning said mask on said substrate via-surface; wherein the openings of said through-via are wider at said mask via-surface than at said substrate-contact surface and said through-via has multiple substrate-contact surface openings.