Formation of deep trench airgaps and related applications
First Claim
1. A bipolar complementary metal oxide semiconductor device, the device comprising:
- a substrate having a trench therein, the trench having walls and a bottom;
an airgap enclosed in the trench in the substrate, the airgap having a top, a bottom, and sides, wherein the top of the airgap is enclosed by a portion of spacers and a portion of a layer above the spacers, the portion of the spacers and the portion of the layer above the spacers sealing the opening of the trench;
an oxide separating layer atop the walls and the bottom of the trench;
an extra oxide liner atop the oxide separating layer, wherein the spacers are situated atop the extra oxide liner; and
a first field area and a second field area formed inside said substrate, wherein the airgap is situated between the first field area and the second field area.
1 Assignment
0 Petitions
Accused Products
Abstract
A method for forming deep trench or via airgaps in a semiconductor substrate is disclosed comprising the steps of patterning a hole in the substrate, partly fill said hole with a sacrificial material (e.g. poly-Si), depositing spacers on the sidewalls of the unfilled part of the hole (e.g. TEOS) to narrow the opening, removing through said narrowed opening the remaining part of the sacrificial material (e.g. by isotropic etching) and finally sealing the opening of the airgap by depositing a conformal layer (TEOS) above the spacers. The method of forming an airgap is demonstrated successfully for use as deep trench isolation structures in BiCMOS devices.
65 Citations
18 Claims
-
1. A bipolar complementary metal oxide semiconductor device, the device comprising:
-
a substrate having a trench therein, the trench having walls and a bottom; an airgap enclosed in the trench in the substrate, the airgap having a top, a bottom, and sides, wherein the top of the airgap is enclosed by a portion of spacers and a portion of a layer above the spacers, the portion of the spacers and the portion of the layer above the spacers sealing the opening of the trench; an oxide separating layer atop the walls and the bottom of the trench; an extra oxide liner atop the oxide separating layer, wherein the spacers are situated atop the extra oxide liner; and a first field area and a second field area formed inside said substrate, wherein the airgap is situated between the first field area and the second field area. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A bipolar complementary metal oxide semiconductor device, the device comprising:
-
a substrate having a trench therein, the trench having walls and a bottom, wherein an oxide separating layer is situated atop the walls and the bottom of the trench, and an extra oxide liner is situated atop the oxide separating layer; an airgap enclosed in the trench in the substrate, the airgap having a top, a bottom, and sides, wherein the top of the airgap is enclosed by spacers and a planarized sealing layer, wherein the spacers are situated atop the extra oxide liner; a planarized first field area and a planarized second field area formed inside said substrate, wherein the airgap is situated between the planarized first field area and the planarized second field area. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
-
Specification