Etching solution having silicon oxide corrosion inhibitor and method of using the same

Patent metadata

Field	Value
Publication number	US-11180697-B2
Application number	US-201916681246-A
Country	US
Kind code	B2
Filing date	Nov 12, 2019
Priority date	Nov 19, 2018
Publication date	Nov 23, 2021
Grant date	Nov 23, 2021

Abstract

Described herein is an etching solution suitable for the selective removal of polysilicon over silicon oxide from a microelectronic device, which comprises: water; at least one of a quaternary ammonium hydroxide compound; optionally at least one alkanolamine compound; a water-miscible solvent; at least one nitrogen containing compound selected from the group consisting of a C4-12 alkylamine, a polyalkylenimine, a polyamine, a nitrogen-containing heterocyclic compound, a nitrogen-containing aromatic compound, or a nitrogen-containing heterocyclic and aromatic compound; and optionally, a surfactant.

First claim

The invention claimed is:

1. An etching solution suitable for the selective removal of polysilicon over silicon oxide from a microelectronic device, which comprises:
water;
about 1 wt % of neat tetramethyl ammonium hydroxide (TMAH);
about 15 wt % to about 20 wt % of monoethanolamine (MEA);
about 50 wt % to about 59.5 wt % of ethylene glycol (EG);
about 0.5 wt % of 8-hydroxyquinoline (8-HQ); and
optionally, a surfactant.

2. The etching solution of claim 1 , wherein the at least one water-miscible organic solvent comprises about 55 wt % of ethylene glycol (EG).

3. The etching solution of claim 1 comprising:
water;
about 1 wt % neat of tetramethyl ammonium hydroxide (TMAH);
about 20 wt % of monoethanolamine (MEA);
from about 50 to about 55 wt % of ethylene glycol (EG); and
about 0.5 wt % of 8-hydroxyquinoline (8-HQ).

4. A method for selectively enhancing the etch rate of polysilicon relative to silicon oxide in a composite semiconductor device comprising polysilicon and silicon oxide, the method comprising the steps of:
contacting the composite semiconductor device comprising polysilicon and silicon oxide with the etching solution of claim 1 ; and
rinsing the composite semiconductor device after the polysilicon is at least partially removed, wherein the selectivity of the etch for silicon over silicon oxide is greater than 1,000.

5. The method of claim 4 further comprising the step of drying the semiconductor device.

6. The method of claim 4 wherein the selectivity of the etch for silicon over silicon oxide is greater than 15,000.

7. The method of claim 4 wherein the selectivity of the etch for silicon nitride over silicon oxide is greater than 20,000.

8. The method of claim 4 wherein the contacting step is performed at a temperature of from about 25° C. to about 100° C.

Assignees

• Versum Mat Us Llc

Inventors

• Liu Wen Dar
• Lee Yi-Chia
• Chang Chung-Yi

Classifications

• H10P50/667

  by liquid etching only · CPC title

• H10P50/642

  Chemical etching · CPC title

• H10D64/017

  using dummy gates in processes wherein at least parts of the final gates are self-aligned to the dummy gates, i.e. replacement gate processes · CPC title

• C09K13/00 Primary

  Etching, surface-brightening or pickling compositions (for glass C03C15/00, {C03C25/66; for mortars, concrete, artificial or natural stone or ceramics C04B41/5338}; for metallic material C23F, C23G1/00, C25F1/00; {for semi-conductors H10P52/40}) · CPC title

• C30B33/10 Primary

  in solutions or melts · CPC title