US 5,883,012 A · Method of etching a trench into a semiconductor substrate

Abstract

Trench structures (12,32,35,46) are formed in single crystal silicon substrates (10,30) that have either a (110) or (112) orientation. A selective wet etch solution is used that removes only the exposed portions of the single crystal silicon substrates (10,30) that are in the (110) or (112) crystal planes. The trench structures (12,32,35,46) are defined by the {111} crystal planes in the single crystal silicon substrate (10,30) that are exposed during the selective wet etch process. Trench structures (32,35) can be formed on both sides of a single crystal silicon substrate (30) to form an opening (34). Opening (34) can be used as an alignment mark to align front side processing to backside and vice versa. Trench structures can also be use to form a microstructure (41,61) for a sensor (40,60).

Claims22

Dependent claims

A method for etching a semiconductor substrate, the method comprising the steps of:

providing a semiconductor substrate having a top surface and a bottom surface, wherein the top surface is of a (110) crystal plane orientation;
disposing a masking layer overlying the top surface of the semiconductor substrate;
removing a portion of the masking layer to provide an exposed portion of the top surface, the exposed portion of the top surface having a width;
and
etching the exposed portion of the top surface of the semiconductor substrate along a <110>
direction thereby forming a trench, the trench extending from the top surface and comprising two parallel planes along a <111>
direction.

4 more elements

A method for forming a semiconductor device, the method comprising the steps of:

providing a single crystal silicon substrate having a top surface and a bottom surface, wherein the single crystal silicon substrate is of a (110) crystal plane orientation;
forming a masking layer on the top surface and the bottom surface of the single crystal silicon substrate;
patterning the masking layer to provide an exposed portion of the top surface and an exposed portion of the bottom surface of the single crystal silicon substrate;
etching the single crystal silicon substrate from the top surface and the bottom surface along a <110>
direction such that (111) crystal planes of the single crystal silicon substrate are exposed so that a trench is formed on both the top surface and the bottom surface of the single crystal silicon substrate, the trench on the top surface and the trench on the bottom surface comprising parallel planes along a <111>
direction;
bonding a substrate to the single crystal silicon substrate;
and
etching the single crystal silicon substrate from the top surface along the <110>
direction such that (111) crystal planes of the single crystal silicon substrate are exposed so that the trench from the top surface intersects the trench on the bottom surface to provide a microstructure.

7 more elements

Dependencies are inferred from the claim text.

Method of etching a trench into a semiconductor substrate

Life of this patent

Method of etching a trench into a semiconductor substrate

Life of this patent

Abstract

Claims22