Method of forming a through substrate via in a compound semiconductor
AssigneeNorthrop Grumann Systems Corporation
InventorsHarlan C. Cramer, Dale E. Dawson
Life of this patent
Estimating the term…
Abstract
A method is provided for forming a through substrate via in a compound semiconductor having a transistor on a front side of the substrate. The method comprises forming a protective stop pad over a contact area on the front side of the substrate, forming a contact pad overlying the protective stop pad, such that the contact pad is in contact with a terminal of the transistor and plasma etching a backside of the substrate to form a contact coupling via to the protective stop pad. The method further comprises performing a chemical wet etch to remove the protective stop pad and depositing a conductive contact layer in the contact coupling via to provide a conductive contact to the contact pad.
Claims24
A method for forming a through substrate via in a compound semiconductor having a transistor on a front side of the substrate, the method comprising:
- forming a protective stop pad over a contact area on the front side of the substrate, wherein the protective stop pad is spaced apart from the transistor;
- forming a contact pad overlying the protective stop pad, the contact pad being in contact with a terminal of the transistor;
- plasma etching a backside of the substrate to form a contact coupling via to the protective stop pad;
- performing a chemical wet etch to remove the protective stop pad;
- and
- depositing a conductive contact layer in the contact coupling via to provide a conductive contact to the contact pad.
The method of claim of 1, wherein the substrate is formed from one of Gallium Arsenide (GaAs) and Indium Phosphide (InP).
A method for forming a through substrate via in a Gallium Arsenide (GaAs) substrate having a high electron mobility transistor (HEMT) on a front side of the substrate, the method comprising:
- depositing a dielectric layer over a contact area on the front side of the substrate;
- chemically wet etching the dielectric layer to form a protective stop pad;
- forming a contact pad overlying the protective stop pad, the contact pad being in contact with a terminal of the HEMT;
- plasma etching a backside of the substrate to form a contact coupling via to the protective stop pad;
- performing a chemical wet etch to remove the protective stop pad;
- and
- depositing a conductive contact layer in the contact coupling via to provide a conductive contact to the contact pad.
A method for forming a through substrate via in a Gallium Arsenide (GaAs) substrate having an Indium Arsenide (InAs) high electron mobility transistor (HEMT) on a front side of the substrate, the method comprising:
- depositing a silicon nitride (Si3N4), (SiN) layer over a contact area on the front side of the substrate;
- chemically wet etching the silicon nitride layer to form a protective stop pad;
- forming a contact pad overlying the protective stop pad, the contact pad being in contact with a terminal of the HEMT;
- plasma etching a backside of the substrate at an etch rate of about 1 to about 10 microns/minute to form a contact coupling via to the protective stop pad;
- performing a chemical wet etch to remove the protective stop pad;
- and
- depositing a conductive contact layer in the contact coupling via to provide a conductive contact to the contact pad.
A method for forming a through substrate via in a compound semiconductor having a transistor on a front side of the substrate, the method comprising:
- forming a protective stop pad over a contact area on the front side of the substrate;
- forming a contact pad overlying the protective stop pad, the contact pad being in contact with a terminal of the transistor;
- plasma etching a backside of the substrate to form a contact coupling via to the protective stop pad, wherein the protective stop pad insulates the transistor from voltage effects during the plasma etching;
- performing a chemical wet etch to remove the protective stop pad;
- and
- depositing a conductive contact layer in the contact coupling via to provide a conductive contact to the contact pad.
Dependencies are inferred from the claim text.