US 8,940,631 B1 · Methods of forming coaxial feedthroughs for 3D integrated circuits

Abstract

Methods of forming coaxial feedthroughs for 3d integrated circuits that provide excellent isolation of signal paths from the substrate and from adjacent feedthroughs. One method is to form a recess in a substrate and deposit alternate layers of insulation and conductive layers and then thin the substrate to make the layers available from both sides of the substrate, with the first metal layer forming the coaxial conductor and the second metal layer forming the central conductor. Alternatively the coaxial feedthroughs may be formed using a modified pillar process to form the coaxial conductor at the same time as the center conductor is formed so that the coaxial feedthrough is formed without requiring extra steps. Both processes are low temperature processes.

Claims13

Dependent claims

A method of making coaxial feedthroughs in a substrate comprising:

a) forming a depression in the substrate;
b) depositing a first insulative layer;
c) depositing a first conductive layer;
d) depositing a second insulative layer;
e) depositing a second conductive layer;
f) thinning the substrate to expose the first insulative layer;
g) depositing a third insulative layer;
h) forming an opening through the third and first insulative layers, the first conductive layer and the second insulative layer to expose an area of the second conductive layer;
i) depositing a fourth insulative layer;
j) removing portions of the fourth insulative layer to expose an area of the second conductive layer;
k) depositing and patterning a third conductive layer to define a first electrical connection to the first conductive layer and a second electrical connection to the second conductive layer.

8 more elements

Dependencies are inferred from the claim text.

Methods of forming coaxial feedthroughs for 3D integrated circuits

Life of this patent

Methods of forming coaxial feedthroughs for 3D integrated circuits

Life of this patent

Abstract

Claims13