# US 10,312,073 B2 · Selective removal of carbon-containing and nitrogen-containing silicon residues

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- Number: US 10,312,073 B2
- Document ID: US10312073B2
- Status: Granted
- Kind: B2
- Application number: 15/870,603
- Filed: 2018-01-12
- Published: 2018-11-01
- Granted: 2019-06-04
- Earliest claimed: 2017-04-28
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Yao-Wen Hsu; Jian-Jou Lian; Neng-Jye Yang; Kuan-Lin Chen
- Web page: https://patentgrep.com/patent/US10312073B2

## CPC

- H10P 70/27: {during, before or after processing of conductive materials, e.g. polysilicon or amorphous silicon layers}
- C11D 3/044: {Hydroxides or bases}
- C11D 7/505: {Mixtures of (hydro)fluorocarbons}
- H10P 50/242: {of Group IV materials}
- H10P 70/234: {the processing being the formation of vias or contact holes}
- H10P 76/4085: {characterised by the processes involved to create the masks}
- C23F 1/10: Etching compositions (C23F1/44 takes precedence)
- C23F 1/16: Acidic compositions (C23F1/42 takes precedence)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- C11D: DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C23F: NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE (working metal by laser beams B23K26/00; desurfacing by applying flames B23K7/00; working of metal by electro-erosion B23H; producing decorative effects by removing surface material, e.g. by engraving, by etching, B44C1/22; electrolytic etching or polishing C25F); INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25

## Abstract

A semi-aqueous wet clean system and method for removing carbon-containing silicon material (e.g., plasma residue) or nitrogen-containing silicon material (e.g., plasma residue) includes a hydroxyl-terminated organic compound, a diol, and a fluoride ion donor material. The system is configured to protect silicon oxide and amorphous silicon during a post-dry-etch wet clean. The wet clean system is configured to selectively remove carbon-containing or nitrogen-containing plasma residue. pH of the wet clean system can be modified to tune selectivity for removal of carbon-containing or nitrogen-containing plasma residues. As a result, positive TEOS recession of less than about 3 nanometers may be achieved. Additionally, the wet clean system can be adapted for reclamation and subsequent reuse.

## Claims

### Claim 1

A system for use in semiconductor device manufacture, the system comprising:
an at least partly aqueous system configured to remove at least one of carbon-containing silicon residue or nitrogen-containing silicon residue, the at least partly aqueous system comprising:
water in a range of about 54.5% (wt/wt) to about 92.8% (wt/wt);
1-(2-hydroxyethyl)-2-pyrrolidone in a range of about % (wt/wt) to about 30% (wt/wt);
a mixture of ammonium fluoride and ammonium bifluoride in a range of about 0.2% (wt/wt) to about 92.8% (wt/wt); and
diethylene glycol in about 2% (wt/wt) to about 15% (wt/wt).

### Claim 2 (depends on 1)

The system of claim 1, wherein the at least partly aqueous system comprises the mixture of ammonium fluoride and ammonium bifluoride in a range of about 0.2% (wt/wt) to about 0.5% (wt/wt) of the at least partly aqueous system.

### Claim 3 (depends on 1)

The system of claim 1, wherein the at least partially aqueous system further comprises a pH between about 4.5 and about 5.5.

### Claim 4 (depends on 1)

The system of claim 1, wherein the at least partially aqueous system further comprises a buffer.

### Claim 5 (depends on 4)

The system of claim 4, the buffer being monoethanolamine (MEA).

### Claim 6 (depends on 5)

The system of claim 5, wherein the pH is about 5.3.

### Claim 7

A method for use in semiconductor device manufacture, the method comprising:
etching a semiconductor device layer, wherein the etching produces at least one of a carbon-containing silicon residue or a nitrogen-containing silicon residue; and
after etching the semiconductor device layer, cleaning the semiconductor device layer to at least partially remove at least one of the carbon-containing silicon residue or the nitrogen-containing silicon residue with a cleaning system comprising:
water in a range of about 54.5% (wt/wt) to about 92.8% (wt/wt);
a hydroxyl-terminated organic material comprising 1-(2-hydroxyethyl)-2-pyrrolidone in a range of about 5% (wt/wt) to about 30% (wt/wt);
a diol comprising diethylene glycol in a range of about 2% (wt/wt) to about 15% (wt/wt); and
a fluoride ion donor material comprising a combination of ammonium fluoride and ammonium bifluoride in a range of about 0.2% (Wt/Wt) to about 92.8% (wt/wt).

### Claim 8 (depends on 7)

The method of claim 7, wherein the etching is performed with a plasma comprising at least CxHyFz.

### Claim 9 (depends on 7)

The method of claim 7, wherein the semiconductor device layer comprises amorphous silicon.

### Claim 10 (depends on 7)

The method of claim 7, wherein the cleaning the semiconductor device layer further comprises a cleaning time of between about 60 seconds and about 600 seconds at a temperature of between about 30° C. and about 70° C.

### Claim 11 (depends on 7)

The method of claim 7, wherein the etching is performed with a plasma comprising N2.

### Claim 12 (depends on 11)

The method of claim 11, wherein the cleaning comprises at least partial removal of the at least one of the carbon-containing silicon residue or the nitrogen-containing silicon residue from a silicon-containing structure.

### Claim 13 (depends on 12)

The method of claim 12, wherein the cleaning is selective for at least partial removal of the at least one of the carbon-containing silicon residue or the nitrogen-containing silicon residue relative to material forming the silicon-containing structure.

### Claim 14 (depends on 13)

The method of claim 13, wherein the cleaning is selective for at least partial removal of the at least one of the carbon-containing silicon residue or the nitrogen-containing silicon residue relative to at least one of amorphous silicon or silicon oxide.

### Claim 15

A method for use in semiconductor device manufacture, the method comprising:
dry etching a semiconductor structure with a plasma, the semiconductor structure comprising at least one of amorphous silicon or silicon oxide; the plasma comprising at least one of CO2, CxHyFz, or N2, wherein the dry etching produces at least one of a carbon-containing silicon material or a nitrogen-containing silicon material; and
after dry etching the semiconductor structure, reducing a concentration of at least one of the carbon-containing silicon material or the nitrogen-containing silicon material with an at least partially aqueous system consisting of:
about 5% (wt/wt) to about 30% (wt/wt) 1-(2-hydroxyethyl)-2-pyrrolidone;
about 2% (wt/wt) to about 15% (wt/wt) diethylene glycol;
about 0.2% (wt/wt) to about 92.8% (wt/wt) a combination of ammonium fluoride and ammonium bifluoride; and
about 54.5% (wt/wt) to about 92.8% (wt/wt) water.

### Claim 16 (depends on 15)

The method of claim 15, wherein the reducing the concentration of at least one of the carbon-containing silicon material or the nitrogen-containing silicon material reduces the amount of carbon by a factor of at least about 3.

### Claim 17 (depends on 15)

The method of claim 15, wherein the semiconductor structure comprises a hard mask layer.

### Claim 18 (depends on 17)

The method of claim 17, wherein the hard mask layer is formed to have a thickness from about 100 Angstroms to about 1000 Angstroms.

### Claim 19 (depends on 15)

The method of claim 15, wherein the dry etching the semiconductor structure comprises forming mandrels, such that the carbon-containing silicon material or the nitrogen-containing silicon material is produced on or in surface portions of the mandrels.

### Claim 20 (depends on 19)

The method of claim 19, wherein the at least partially aqueous system comprises a water ratio of about 60%.