Formation of deep trench airgaps and related applications
AssigneeInteruniversitair Microelektronica Centrum vzw (IMEC)
InventorEddy Kunnen
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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.
Claims20
A method for forming an airgap in a substrate, the method comprising the steps of:
- patterning a hole having sidewalls in the substrate;
- forming a partially filled-in portion of the hole, wherein the partially filled-in portion comprises a sacrificial material, whereby a portion of the sidewalls is exposed and a portion of the sidewalls is covered by the sacrificial material;
- depositing spacers on the exposed portion of the sidewalls, whereby an opening to the hole is narrowed;
- removing the sacrificial material through the narrowed opening;
- and
- sealing the opening by depositing a layer above the spacers, whereby an airgap is formed.
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;
- and
- a first field area and a second field area, wherein the airgap is situated between the first field area and the second field area.
Dependencies are inferred from the claim text.