Patent ID: 8729591

Claim:
A sub-mount for an optoelectronic device comprising: a silicon substrate having a front-side surface and a back-side surface, the substrate having a recess defined in its front-side, wherein the front-side surface and the back-side surface extend between side edges of the silicon substrate; electrical contact pads disposed on a bottom surface of the recess, and a die attach pad on which to mount the optoelectronic device, wherein the die attach pad is disposed on the bottom surface of the recess; and feedthrough metallization in via structures, each of the via structures extending through the substrate from the bottom surface of the recess to the back-side surface of the substrate, wherein the feedthrough metallization in the via structures electrically couples the contact pads disposed within the recess to respective contact pads on the back-side surface of the substrate; wherein one via structure from the via structures has a sidewall extending through the silicon substrate from the bottom surface of the recess to the back-side surface of the silicon substrate, wherein the sidewall includes a first portion covered with the feedthrough metallization and a second portion that is without the feedthrough metallization, wherein the feedthrough metallization covering the first portion of the sidewall extends distally toward the back-side surface and includes a distal most end surface that is spaced from the back-side surface toward the front-side surface, wherein the distal most end surface of the feedthrough metallization covering the first portion of the sidewall is positioned within the one via structure, wherein the sidewall of the one via structure extends continuously to one of the side edges of the silicon substrate such that the one via structure is exposed at said side edge of the silicon substrate.