# US 9,752,057 B2 · CMP method for suppression of titanium nitride and titanium/titanium nitride removal

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- Number: US 9,752,057 B2
- Document ID: US9752057B2
- Status: Granted
- Kind: B2
- Application number: 14/616,250
- Filed: 2015-02-06
- Published: 2015-08-06
- Granted: 2017-09-05
- Earliest claimed: 2014-02-05
- Assignees: Cabot Microelectronics Corporation
- Applicants: Cabot Microelectronics Corporation
- Inventors: Hui-Fang Hou; William Ward; Ming-Chih Yeh; Chih-Pin Tsai
- Web page: https://patentgrep.com/patent/US9752057B2

## CPC

- C09G 1/02: containing abrasives or grinding agents {(abrasives as such C09K3/14; polishing of semi-conductors H10P52/40)}
- C09K 3/1463: {Aqueous liquid suspensions}
- C23F 3/06: with acidic solutions
- H10P 52/403: {of conductive or resistive materials}
- H10P 95/062: {involving a dielectric removal step}
- H10P 95/08: {Planarisation of organic insulating materials}
- C09G: POLISHING COMPOSITIONS (French polish C09F11/00); SKI WAXES
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- 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
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A chemical mechanical polishing (CMP) method for removal of a metal layer deposited over a titanium nitride (TiN) or titanium/titanium nitride (Ti/TiN) barrier layer is described herein. The method comprises abrading the metal layer with an acidic CMP composition to expose the underlying TiN or Ti/TiN layer, wherein the TiN or Ti/N layer is polished at a low rate due to the presence of a surfactant inhibitor. The acidic CMP composition comprises a particulate abrasive (e.g., silica, alumina) suspended in a liquid carrier containing a surfactant selected from the group consisting of an anionic surfactant, a nonionic surfactant, cation surfactants, and a combination thereof.

## Claims

### Claim 1

A chemical mechanical polishing (CMP) method of polishing a substrate comprising a metal deposited over a titanium nitride (TiN) or titanium/titanium nitride (Ti/TiN) barrier layer; the method comprising contacting the substrate with an acidic CMP composition comprising a particulate abrasive suspended in a liquid carrier, wherein the particulate abrasive comprises alumina, and has a mean particle size of about 10 to about 150 nm, the liquid carrier comprising a surfactant, wherein the surfactant comprises a mixture of (C10-C14) alkylbenzene and ethoxylated (C6-C12) alcohols, wherein the surfactant suppresses a rate at which the TiN and Ti/TiN is polished, and wherein pH of the composition is in the range of about 2 to about 5.

### Claim 2 (depends on 1)

The method of claim 1 wherein the particulate abrasive is present in the CMP composition at a concentration of about 0.001 to about 10 percent by weight (wt %).

### Claim 3 (depends on 1)

The method of claim 1 wherein the surfactant is present in the CMP composition at a concentration in the range of about 10 to about 50,000 parts-per-million (ppm).

### Claim 4 (depends on 1)

The method of claim 1 wherein the CMP composition further comprises an oxidizing agent.

### Claim 5 (depends on 4)

The method of claim 4 wherein the oxidizing agent comprises hydrogen peroxide.

### Claim 6 (depends on 5)

The method of claim 5 wherein the hydrogen peroxide is present in the CMP composition at a concentration in the range of about 0.01 to about 5 wt %.

### Claim 7 (depends on 1)

The method of claim 1 wherein the abrading is accomplished in conjunction with a polishing pad in a CMP polishing apparatus.

### Claim 8 (depends on 1)

The method of claim 1 wherein the CMP composition comprises about 0.001 to about 10 wt % of the abrasive, about 10 to about 50,000 ppm of the sulfonate surfactant, and further comprising about 0.01 to about 5 wt % of hydrogen peroxide.