# US 8,784,572 B2 · Method for cleaning platinum residues on a semiconductor substrate

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- Number: US 8,784,572 B2
- Document ID: US8784572B2
- Status: Granted
- Kind: B2
- Application number: 13/276,973
- Filed: 2011-10-19
- Published: 2013-04-25
- Granted: 2014-07-22
- Earliest claimed: 2011-10-19
- Assignees: Intermolecular, Inc.
- Applicants: Anh Duong; Sean Barstow; Olov Karlsson; Bei Li; James Mavrinac
- Inventors: Anh Duong; Sean Barstow; Olov Karlsson; Bei Li; James Mavrinac
- Web page: https://patentgrep.com/patent/US8784572B2

## CPC

- H10P 70/15: {by wet cleaning only (H10P70/52 takes precedence)}
- H10D 30/0212: {using self-aligned silicidation}
- H10P 70/27: {during, before or after processing of conductive materials, e.g. polysilicon or amorphous silicon layers}
- H10D 64/0112: {using conductive layers comprising silicides}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

A method for cleaning platinum residues from a surface of a substrate is provided. The method initiates with exposing the surface to a first solution containing a mixture of nitric acid and hydrochloric acid. Then, the surface is exposed to a second solution containing hydrochloric acid.

## Claims

### Claim 1

A method for cleaning platinum residues from a surface of a semiconductor substrate, comprising:
exposing the surface of the semiconductor substrate to a first solution containing a mixture of nitric acid and hydrochloric acid;
saturating a second solution with chlorine gas prior to applying the second solution to the surface of the semiconductor substrate; and
after exposing the surface of the semiconductor substrate to the first solution, exposing the surface of the semiconductor substrate to the second solution containing hydrochloric acid wherein the first solution and the second solution are different.

### Claim 2 (depends on 1)

The method for cleaning platinum residues from a surface of a semiconductor substrate as recited in claim 1,
wherein the molar ratio of nitric acid to hydrochloric acid in the first solution is approximately 1:3 to 1:12; and wherein the second solution has a concentration of hydrochloric acid of approximately 10% to 20% by volume.

### Claim 3 (depends on 1)

The method for cleaning platinum residues from a surface of a semiconductor substrate as recited in claim 1,
wherein the exposure to the first solution is performed at approximately 20 to 30 degrees Celsius for approximately 3 to 7 minutes.

### Claim 4 (depends on 1)

The method for cleaning platinum residues from a surface of a semiconductor substrate as recited in claim 1,
wherein the exposure to the second solution is performed at approximately 40 to 80 degrees Celsius for approximately 1 to 5 minutes.

### Claim 5 (depends on 1)

The method for cleaning platinum residues from a surface of a semiconductor substrate as recited in claim 1,
wherein the exposure to the second solution is performed at approximately 60 to 80 degrees Celsius for approximately 1 to 3 minutes.

### Claim 6 (depends on 1)

The method for cleaning platinum residues from a surface of a semiconductor substrate as recited in claim 1, further comprising,
after the exposure to the first solution, rinsing the surface of the substrate with de-ionized water before exposing the surface to the second solution.

### Claim 7 (depends on 6)

The method for cleaning platinum residues from a surface of a semiconductor substrate as recited in claim 6,
wherein the rinsing of the surface is performed at approximately 20 to 30 degrees Celsius for approximately 1 to 3 minutes.

### Claim 8

A method for cleaning platinum residues from a surface of a semiconductor substrate, comprising:
exposing the surface the semiconductor substrate of to a first solution containing a mixture of nitric acid and hydrochloric acid at a molar ratio of approximately 1:3 to 1:12;
rinsing the surface of the semiconductor substrate with deionized water;
saturating a second solution with chlorine gas prior to applying the second solution to the surface of the semiconductor substrate; and
exposing the surface of the semiconductor substrate to a second solution containing hydrochloric acid at a concentration of approximately 10% to 20% by volume wherein the first solution and the second solution are different.

### Claim 9 (depends on 8)

The method for cleaning platinum residues from a surface of a semiconductor substrate as recited in claim 8, further comprising:
after rinsing the surface of the substrate, drying the surface with an inert gas prior to exposing the surface to the second solution.

### Claim 10 (depends on 9)

The method for cleaning platinum residues from a surface of a semiconductor substrate as recited in claim 9, wherein the inert gas is nitrogen.

### Claim 11 (depends on 8)

The method for cleaning platinum residues from a surface of a semiconductor substrate as recited in claim 8,
wherein the exposure to the first solution is performed at approximately 20 to 30 degrees Celsius for approximately 3 to 7 minutes; and
wherein the exposure to the second solution is performed at approximately 60 to 80 degrees Celsius for approximately 1 to 3 minutes.