IP Library Granted Patent US 10,113,113
Granted Patent B2
US 10,113,113 · App. 15/590,593 · Granted Oct 30, 2018

Removing polysilicon

Inventors: Jerome A. Imonigie (Boise, ID); Prashant Raghu (Boise, ID)
Assignee: Micron Technology, Inc.
C09K13/08C09K13/00C09K13/04C09K13/06H01L21/28273H01L21/30604H01L21/31111H01L21/32134H01L27/11556
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Quick Facts
Patent No.
US 10,113,113
App. No.
15/590,593
Granted
Oct 30, 2018
Kind
B2
Abstract

Methods include exposing polysilicon to an aqueous composition comprising nitric acid, poly-carboxylic acid and ammonium fluoride, and removing a portion of the polysilicon selective to an oxide using the aqueous composition.

Claims (17)

1. A method, comprising:

forming a first instance of oxide;

forming an instance of polysilicon over the instance of oxide;

forming a second instance of oxide over the instance of polysilicon;

forming an opening through the second instance of oxide, the instance of polysilicon and the first instance of oxide;

exposing the second instance of oxide, the instance of polysilicon and the first instance of oxide to an aqueous composition; and

using the aqueous composition, recessing the instance of polysilicon relative to the first instance of oxide and the second instance of oxide within the opening;

wherein the aqueous composition comprises nitric acid, poly-carboxylic acid and ammonium fluoride.

2. The method of claim 1 , further comprising using the aqueous composition comprising a water content of less than or equal to 39 wt %.

3. The method of claim 2 , further comprising using the aqueous composition comprising a water content of less than or equal to 35 wt %.

4. The method of claim 1 , further comprising using the aqueous composition comprising 65-70 wt % nitric acid, 0.06-0.6 wt % ammonium fluoride, and poly-carboxylic acid at 0.4 wt % or less.

5. The method of claim 4 , further comprising using the aqueous composition, wherein the poly-carboxylic acid is oxalic acid.

6. The method of claim 4 , further comprising using the aqueous composition further comprising hydrofluoric acid.

7. The method of claim 6 , further comprising using the aqueous composition comprising hydrofluoric acid at 0.08 wt % or less.

8. The method of claim 7 , further comprising using the aqueous composition, wherein the poly-carboxylic acid is oxalic acid.

9. The method of claim 1 , wherein forming the instance of polysilicon comprises forming an instance of boron-doped polysilicon.

10. The method of claim 9 , wherein forming the second instance of oxide comprises forming an instance of a silicon oxide or a silicon oxynitride.

Assignments (6)
RELEASE OF SECURITY INTEREST Recorded Nov 12, 2019
From: JPMORGAN CHASE BANK, N.A., AS COLLATERAL AGENT
To: MICRON TECHNOLOGY, INC.; MICRON SEMICONDUCTOR PRODUCTS, INC.
Reel/Frame 051028/0001 →
RELEASE OF SECURITY INTEREST Recorded Oct 10, 2019
From: MORGAN STANLEY SENIOR FUNDING, INC., AS COLLATERAL AGENT
To: MICRON TECHNOLOGY, INC.
Reel/Frame 050700/0535 →
RELEASE OF SECURITY INTEREST Recorded Jul 20, 2018
From: U.S. BANK NATIONAL ASSOCIATION, AS AGENT
To: MICRON TECHNOLOGY, INC.
Reel/Frame 046597/0393 →
SECURITY INTEREST Recorded Jul 13, 2018
From: MICRON TECHNOLOGY, INC.; MICRON SEMICONDUCTOR PRODUCTS, INC.
To: JPMORGAN CHASE BANK, N.A., AS COLLATERAL AGENT
Reel/Frame 047540/0001 →
SUPPLEMENT NO. 5 TO PATENT SECURITY AGREEMENT Recorded Aug 8, 2017
From: MICRON TECHNOLOGY, INC.
To: MORGAN STANLEY SENIOR FUNDING, INC.
Reel/Frame 043482/0776 →
SUPPLEMENT NO. 5 TO PATENT SECURITY AGREEMENT Recorded Aug 8, 2017
From: MICRON TECHNOLOGY, INC.
To: U.S. BANK NATIONAL ASSOCIATION
Reel/Frame 043483/0686 →
Continuity (3)
Continuation 14672870 · Mar 30, 2015
Division 13624272 · Sep 21, 2012
Related Publication 20170243758A1 · Aug 24, 2017