Composition for post chemical-mechanical-polishing cleaning

Abstract

Described is a post chemical-mechanical-polishing (post-CMP) cleaning composition comprising or consisting of: (A) one or more water-soluble nonionic copolymers of the general formula (I) and mixtures thereof, formula (I) wherein R.sub.1 and R.sub.3 are independently from each other hydrogen, methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-Butyl, or sec-butyl, R.sub.2 is methyl and x and y are an integer, 1 (B)poly(acrylic acid) (PAA) or acrylic acid-maleic acid copolymer with a mass average molar mass (Mw) of up to 10,000 g/mol, and (C) water, wherein the pH of the composition is in the range of from 7.0 to 10.5. ##STR00001##

Claims

1. A post chemical-mechanical-polishing cleaning composition, comprising: (A) a water-soluble nonionic copolymer which is a block copolymer of formula (I), an alternating copolymer of formula (II), or a random copolymer with units represented in formulas: ##STR00008## wherein R.sub.1 and R.sub.3 are independently hydrogen, methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, or sec-butyl, and x and y are each independently an integer, a ratio of x to y being in a range of from 0.11 to 9, (B) poly(acrylic acid) or acrylic acid-maleic acid copolymer with a mass average molar mass of up to 10,000 g/mol, and (C) water, wherein a pH of the composition is in a range of from 7.0 to 10.5.

2. The composition of claim 1, wherein the pH is in a range of from 8.0 to 9.0.

3. The composition of claim 1, wherein the copolymer comprises a block copolymer having a mass average molar mass in a range of from 500 to 15,000 g/mol, wherein R.sub.1 and R.sub.3 are independently hydrogen or methyl, R.sub.2 is methyl, and wherein the ratio of x to y is in a range of from 0.25 to 4.

4. The composition of claim 1, wherein the poly(acrylic acid) or acrylic acid-maleic acid copolymer (B) is acrylic acid-maleic acid copolymer with a mass average molar mass of up to 10,000 g/mol.

5. The post chemical mechanical polishing cleaning composition of claim 1, further comprising (D) a corrosion inhibitor.

6. The composition of claim 5, wherein the corrosion inhibitor (D) is at least one selected from the group consisting of acetylcysteine, an N-acyl-sarcosine, an alkylsulfonic acid, an alkyl-aryl sulfonic acid, isophthalic acid, an alkyl phosphate, polyaspartic acid, imidazole, an imidazole derivative, polyethylenimine with a mass average molar mass in a range of from 200 to 2,000 g/mol, a triazole derivative, and an ethylene diamine derivative.

7. The composition of claim 1, further comprising (E) a base.

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

9. The composition of claim 1, which is suitable for a) removing residues and contaminants from a substrate, and/or b) cleaning of semiconductor devices.

10. The composition of claim 1, which is a ready-to-use post chemical-mechanical-polishing cleaning composition, comprising: (A) a total amount of the water-soluble nonionic copolymer 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 poly(acrylic acid) (PAA) or acrylic acid-maleic acid copolymer in a range of from 0.001 to 0.15 wt.-%, based on the total weight of the composition.

11. The composition of claim 1, which is a post chemical-mechanical-polishing (post-CMP) cleaning composition concentrate, comprising: (A) a total amount of the water-soluble nonionic copolymer 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 poly(acrylic acid) (PAA) or acrylic acid-maleic acid copolymer in a range of from 0.1 to 7.5 wt.-%, based on the total weight of the composition.

12. A cobalt post chemical-mechanical-polishing cleaner, comprising: the composition of claim 1.

13. A process for the manufacture of a semiconductor device from a semiconductor substrate, the process comprising: removing residues and contaminants from a surface of the semiconductor substrate by contacting it at least once with the composition of claim 1.

14. The process of claim 13, further comprising: chemical-mechanical-polishing the semiconductor substrate.

15. A method, comprising: cleaning a substrate comprising cobalt with the composition of claim 1.

16. A method, comprising: removing residues and contaminants from a surface of a semiconductor substrate comprising cobalt or a cobalt alloy with the composition of claim 1.

17. The composition of claim 1, comprising no quaternary ammonium cation.

18. The composition of claim 1, having a sodium cation concentration of less than 500 ppm.

19. The composition of claim 1, wherein the nonionic water soluble copolymer (A) has a mass average molar mass (Mw) in a range of from 2000 to 10000 g/mol.

20. The composition of claim 1, comprising the acrylic acid-maleic acid copolymer, wherein the nonionic water soluble copolymer (A) is a block copolymer with a central propyleneoxide block flanked by two polyethyleneglycol blocks.

Description

EXAMPLES AND COMPARATIVE EXAMPLES

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

Examples

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 M at 25 C. and a total organic carbon (TOC) amount of less than 10 ppb were provided. The water was stirred and 500 g block copolymer with a central propyleneoxide block (R.sub.2 of general formula (I) is methyl) flanked by two polyethylene glycol blocks (R.sub.1 and R.sub.3 of general formula I are hydrogen) with a ratio of x to y of 0.66 (x=40, y=60) and a mass average molar mass (Mw) of 2,900 g/mol (Pluronic PE 6400) were added and the solution was stirred for at least 20 minutes until (A) was dissolved. Subsequently, 2,000 g of an aqueous solution (25 wt.-%) of an acrylic acid-maleic acid copolymer (Planapur 12 SEG) and 150 g benzotriazol (BTA) were added to the solution and the solution was stirred for further 10 minutes. The pH value of the solution was adjusted to a desired value of 8.0 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. The concentrate was diluted by 50 with balance water to result in the compositions summarized in table 1.

Examples 2

(3) The post-CMP cleaning composition concentrate of the example 2 is prepared analogously to example 1 by mixing their ingredients. The Table 1 summarizes the compositions after dilution by 50 of the concentrate.

(4) TABLE-US-00001 TABLE 1 The compositions of the post-CMP cleaning composition (Balance: Water) etching Example constituent constituent constituent constituent rate AFM No. (A) (B) (D) (E) pH [/min] measurement 1 PE 6400 Sokalan CP BTA KOH 8.0 2.92W, Good Mw 2900; 12 S; 0.015 wt.-% 1.0Co 0.05 wt.-% 0.025 wt.-% 2 PE 6800 Sokalan CP BTA KOH 8.0 2.75W, good Mw 8000; 12 S; 0.015 wt.-% 0.01Co 0.05 wt.-% 0.025 wt.-%

(5) PE 6800 is a block copolymer with a central propyleneoxide block (R.sub.2 of general formula (I) is methyl) flanked by two polyethylene glycol blocks (R.sub.1 and R.sub.3 of general formula I are hydrogen) with a ratio of x to y of 0.25 (x=80, y=20) and a mass average molar mass (Mw) of 8000 g/mol

Comparative Examples 1 to 4

(6) The compositions of comparative examples 1 to 4 were prepared analogously to example 1 by mixing their ingredients. The Table 2 summarizes their compositions after dilution of the concentrate by 50 with balance water.

(7) TABLE-US-00002 TABLE 2 The compositions of comparative examples 1 to 4 (Balance: Water) etching Comparative rate Example [/min] No. constituent 1 constituent 2 constituent 3 constituent 4 pH Co AFM measurement 1 KOH 8.5 6.7 bad 2 PEG M.sub.w KOH 8.5 2.9 bad 1500; 0.05 wt.-% 3 Sokalan KOH 8.5 7.5 bad CP 12 S; 0.05 wt.-% 4 Sokalan CaCl.sub.2 KOH 8.5 15 bad CP 12 S; 0.1 wt.-% 0.05 wt.-%

(8) Atomic Force Microscopy (AFM) Measurements:

(9) 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 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).

(10) The results are shown in table 1 and 2.

(11) The Etching Rates of the Compositions:

(12) The etching rates of the compositions of the examples 1 to 2 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 and tungsten 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.