Patent ID: 8071461
Filing Date: 2011-12-06
Classification: H01L

Abstract:
1. A method for forming an electronic element incorporating an integrated passive device (IPD) and an active device, comprising: providing a substrate of a first material having a first thermal expansion coefficient (TEC) and having a first surface, wherein the substrate has therein a first portion adapted to receive the active device and a second portion adapted to receive the IPD; forming a mask on the second portion, the mask having spaced-apart openings of a first width; etching spaced-apart trenches of substantially the first width to a first depth in the substrate, leaving columns of substantially undisturbed substrate material between the trenches and other portions of the substrate material beneath the trenches; forming dielectric having a second TEC in the trenches so that a substantially centrally located void is present in the dielectric extending from the first surface into the trenches but not in contact with the other portions of the substrate material beneath the trenches; filling the trenches with solid inclusions that are electrically floating with respect to the substrate and having a third TEC less than the second TEC; forming additional dielectric over the inclusions; and forming the IPD above the dielectric, the additional dielectric, and the inclusions, so that the IPD is electrically isolated from the inclusions.