Electronic elements and devices with trench under bond pad feature

Abstract

Electronic elements having an active device region and bonding pad (BP) region on a common substrate desirably include a dielectric region underlying the BP to reduce the parasitic impedance of the BP and its interconnection as the electronic elements are scaled to higher power and/or operating frequency. Mechanical stress created by plain (e.g., oxide only) dielectric regions can adversely affect performance, manufacturing yield, pad-to-device proximity and occupied area. This can be avoided by providing a composite dielectric region having electrically isolated inclusions of a thermal expansion coefficient (TEC) less than that of the dielectric material in which they are embedded and/or closer to the substrate TEC. For silicon substrates, poly or amorphous silicon is suitable for the inclusions and silicon oxide for the dielectric material. The inclusions preferably have a blade-like shape separated by and enclosed within the dielectric material.