Composition for post chemical-mechanical-polishing cleaning

Abstract

A post chemical-mechanical-polishing (post-CMP) cleaning composition including: (A) polyethylene glycol (PEG) with a mass average molar mass (Mw) in the range of from 400 to 8,000 g/mol, (B) an anionic polymer selected from poly(acrylic acid) (PAA), acrylic acid-maleic acid copolymers, polyaspartic acid (PASA), polyglutamic acid (PGA), polyvinylphosphonic acid, polyvinylsulfonic acid, poly(styrenesulfonic acid), polycarboxylate ethers (PCE), PEG-phosphorous acids, and copolymers of the polymers thereof, and (C) water, where the pH of the composition is from 7.0 to 10.5.

Claims

1. A method of cleaning a substrate post chemical mechanical polishing, comprising cleaning a substrate after the substrate has been polished with a chemical mechanical polishing composition comprising an abrasive with a cleaning composition to remove residues and contaminants from the surface of the semiconductor substrate remaining after the polishing, wherein the cleaning composition comprises: (A) polyethylene glycol (PEG) with a mass average molar mass (Mw) in the range of from 400 to 8,000 g/mol, (B) an anionic polymer selected from the group consisting of poly(acrylic acid) (PAA), acrylic acid-maleic acid copolymers, polyaspartic acid (PASA), poly-glutamic acid (PGA), polyvinylphosphonic acid, polyvinylsulfonic acid, poly(styrenesulfonic acid), polycarboxylate ethers (PCE), PEG-phosphorous acids, and copolymers of said polymers, and (C) water, wherein the pH of the composition is in the range of from 7.0 to 10.5.

2. The method according to claim 1, wherein the pH of the composition is in the range of from 7.5 to 10.

3. The method according to claim 1, wherein i) said anionic polymer (B) is poly(acrylic acid) (PAA) or an acrylic acid-maleic acid copolymer, with a mass average molar mass (Mw) of up to 10,000 g/mol, and/or ii) said polyethylene glycol (PEG) has a mass average molar mass (Mw) in the range of from 600 to 4,000 g/mol.

4. The method according to claim 1, wherein the cleaning composition further comprises (D) a corrosion inhibitor, wherein the total amount of said corrosion inhibitor is in the range of from 0.001 wt.-% to 3 wt.-%, based on the total weight of the composition.

5. The method according to claim 4, wherein the corrosion inhibitor (D) is at least one selected from the group consisting of acetylcysteine, N-acyl-sarcosines, alkylsulfonic acids, alkyl-aryl sulfonic acids, isophthalic acid, alkyl phosphates, polyaspartic acid, imidazole and its derivatives, polyethylenimine with a mass average molar mass (Mw) in the range of from 200 to 2,000 g/mol, derivatives of triazoles, and derivatives of ethylene diamine.

6. The method according to claim 1, wherein the cleaning composition further comprises (E) a defoamer, wherein a total amount of said defoamer is in the range of from 0.01 wt.-% to 0.5 wt. %, based on the total weight of the cleaning composition and/or wherein the defoamer (E) is at least one selected from the group consisting of N-octyl pyrrolidone, monoglycerides of fatty acids, diglycerides of fatty acids, tri-n-butyl phosphate, tri-iso-butyl phosphate, methanol and primary, secondary or tertiary alcohols having 2 to 12 carbon atoms.

7. The method according to claim 1, wherein the cleaning composition further comprises (F) a base.

8. The method according to claim 1, wherein all constituents of the cleaning composition are in the liquid phase.

9. The method according to claim 1, wherein the composition is a ready-to-use post chemical-mechanical-polishing cleaning composition, comprising: (A) a total amount of the polyethylene glycol (PEG) in a range of from 0.001 to 0.15 wt.-%, based on the total weight of the composition, and (B) a total amount of the one or more anionic polymers in a range of from 0.001 to 0.15 wt.-%, based on the total weight of the composition.

10. The method according to claim 1, wherein the composition is a post chemical-mechanical-polishing cleaning composition concentrate, comprising: (A) a total amount of the polyethylene glycol (PEG) in a range of from 0.1 to 7.5 wt.-based on the total weight of the composition, and (B) a total amount of the one or more anionic polymers in a range of from 0.1 to 7.5 wt.-%, based on the total weight of the composition.

11. The method according to claim 1, wherein the composition is employed as cobalt post chemical-mechanical-polishing cleaner and/or for cleaning a substrate comprising cobalt, and/or for removing residues and contaminants from the surface of a semiconductor substrate comprising cobalt or a cobalt alloy.

12. The process according to claim 1, wherein the process is for the manufacture of a semiconductor device from a semiconductor substrate comprising removing residues and contaminants from the surface of the semiconductor substrate by contacting the surface at least once with the composition, wherein the surface is a cobalt or a cobalt alloy-comprising surface.

13. The process according to claim 12, further comprising chemical-mechanical-polishing, wherein the removing of residues and contaminants is performed after the chemical-mechanical-polishing.

Description

EXAMPLES AND COMPARATIVE EXAMPLES

(1) The invention is hereinafter further illustrated by means of examples and comparison examples.

Examples 1 to 8

Example 1

(2) For the preparation of 20,000 g of a post-CMP cleaning composition concentrate, 14,000 g of pure water with an electrical resistivity of above 18 MO at 25 C. and a total organic carbon (TOC) amount of less than 10 ppb were provided. The water was stirred and 500 g polyethylene glycol (PEG) with a mass average molar mass (Mw) of 1,500 g/mol (Pluriol 1500) were added and the solution was stirred for at least 20 minutes until the polyethylene glycol (PEG) was dissolved. Subsequently, 2,000 g of an aqueous solution (25 wt. %) of an acrylic acid-maleic acid copolymer (Planapur 12 SEG) were added to the solution and the solution was stirred for further 20 minutes. The pH value of the solution was adjusted to a desired value of 7.5 by adding of an aqueous potassium hydroxide solution (48 wt.-%). The resulting solution was filled up with pure water to an overall weight of 20,000 g.

Examples 2 to 8

(3) The post-CMP cleaning composition concentrates of the examples 2 to 8 were prepared analogously to example 1 by mixing their ingredients. The Table 1 summarizes their compositions.

(4) TABLE-US-00001 TABLE 1 The compositions of the post-CMP cleaning composition concentrate (Balance: Water) etching rate Example [/min] AFM No. constituent (A) constituent (B) constituent (D) constituent (F) pH Co measurement 1 PEG M.sub.w1500; Sokalan CP KOH 7.5 9.5 good 2.5 wt.-% 12 S; 2.5 wt.-% 2 PEG M.sub.w1500; Sokalan CP Sarkosyl KOH 9.0 7.3 good 2.5 wt.-% 12 S; 2.5 wt.-% O; 0.1 wt.-% 3 PEG M.sub.w1500; Sokalan CP Sarkosyl KOH 7.5 1.6 good 2.5 wt.-% 12 S;; 2.5 wt.-% O; 0.75 wt.-% polyaspartic acid; 0.75 wt.-% 4 PEG M.sub.w1500; Sokalan CP Sarkosyl KOH 7.5 3.7 good 2.5 wt.-% 12 S;; 2.5 wt.-% O; 0.75 wt.-% Imidazol; 2.5 wt.-% 5 PEG M.sub.w1500; Sokalan CP Imidazol; KOH 7.5 0.0 good 2.5 wt.-% 12 S;; 2.5 wt.-% 2.5 wt.-%; Sarkosyl O: 0.75 wt.-%; Quadrol L: 0.75 wt.-% 6 PEG M.sub.w1500; polyaspartic KOH 7.5 3.1 good 2.5 wt.-% acid; 2.5 wt.-%

Comparative Examples 1 to 4

(5) The compositions of comparative examples 1 to 4 were prepared in analogy to example 1 by mixing their ingredients. The Table 2 summarizes their compositions.

(6) TABLE-US-00002 TABLE 2 The compositions of comparative examples 1 to 4 (Balance: Water) Comparative etching rate Example [/min] AFM No. constituent 1 constituent 2 constituent 3 constituent 4 pH Co measurement 1 KOH 8.5 6.7 bad 2 PEG M.sub.w1500; KOH 8.5 2.9 bad 2.5 wt.-% 3 Sokalan CP KOH 8.5 7.5 bad 12S;; 2.5 wt.-% 4 Sokalan CP CaCl.sub.2 KOH 8.5 15 bad 12S;; 2.5 wt.-% 5 wt.-%
Atomic Force Microscopy (AFM) Measurements:

(7) For determining cleaning efficiency with Atomic force microscopy (AFM), a 2.52.5 cm Co (deposited on silicon by a chemical vapor deposition process) wafer coupon which was polished with a BTA and colloidal silica containing barrier CMP Slurry was rinsed with ultra-pure water for 10 s, subsequently dipped for 30 s in a beaker with above mentioned cleaning solutions and stirred with a magnetic stirrer for 30 s (300 rpm). After a final rinsing step for 10 s with ultra-pure water, the coupon was dried with nitrogen flow and submitted to an AFM tool (Bruker ICON, Germany) using tapping mode and a 55 m area with appropriate resolution. The results of the AFM measurement were evaluated and the results were classified in the categories good (few particles), medium (some particles), and bad (many particles). The results are shown in table 1 and 2.

(8) The Etching Rates of the Compositions:

(9) The etching rates of the compositions of the examples 1 to 8 and comparative examples 1 to 4 were measured. All coupons were measured before regarding the thickness of the Co layer by using a 4-point probe device as mentioned below. The above mentioned cobalt coupons were pretreated with a 3% citric acid solution for 5 min to remove native oxide. After rinsing with ultra-pure water, the coupon was immersed in above described PCC solutions for 5 minutes using an agitation by a magnetic stirrer (300 rpm). After removing from the etching bath, the coupons were rinsed with deionized water and the thickness was measured with a 4 point probe device supplied by Napson Corporation, Japan (RG2000). The etching rates (in Angstroms per minute) were calculated. The results are shown in table 1 and 2.