Highly dilutable polishing concentrates and slurries
The present disclosure provides a concentrate for use in chemical mechanical polishing slurries, and a method of diluting that concentrate to a point of use slurry. The concentrate comprises abrasive, complexing agent, and corrosion inhibitor, and the concentrate is diluted with water and oxidizer. These components are present in amounts such that the concentrate can be diluted at very high dilution ratios, without affecting the polishing performance.
1. A method of preparing a chemical mechanical polishing slurry, comprising:
adding water and oxidizer to a concentrate, wherein said concentrate comprises:
about 0.5 wt % to about 10 wt %, based on the total weight of the concentrate, of an abrasive;
about 1 wt % to about 20 wt %, based on the total weight of the concentrate, of a complexing agent; and
a corrosion inhibitor,
wherein said water and said oxidizer are added to said concentrate in an amount governed by the formula:
0.8≦[oxidizer]/ f≦ 2.0,
wherein ƒ=A+B*[complexing agent] C ,
wherein A is between 0.35 and 0.8, B is between 0.3 and 0.5, and C is about 1, and
[oxidizer] and [complexing agent] are the amounts of the oxidizer and complexing agent in the chemical mechanical polishing slurry, respectively, to form the chemical mechanical polishing slurry.
2. The method of claim 1 , wherein 0.8≦[oxidizer]/f≦1.3.
3. The method of claim 1 , wherein said oxidizer is present in an amount of about 0.1 wt % to about 5 wt %, based on the total amount of the chemical mechanical polishing slurry.
4. The method of claim 3 , wherein said oxidizer is present in an amount of about 0.4 wt % to about 2 wt %, based on the total amount of the chemical mechanical polishing slurry.
5. The method of claim 1 , wherein said corrosion inhibitor is present in an amount of 0.001 wt % to about 1 wt %, based on the total weight of the concentrate.
6. The method of claim 1 , wherein said corrosion inhibitor is present in an amount of 0.001 wt % to about 0.2 wt %, based on the total weight of the concentrate.
7. The method of claim 1 , wherein B is between 0.33 and 0.46.
8. The concentrate of claim 1 , wherein said abrasive is selected from the group consisting of alumina, fumed silica, colloidal silica, coated particles, titania, ceria, zirconia, and any combinations thereof.
9. The concentrate of claim 1 , wherein said complexing agent is selected from the group consisting of organic acids and their salts, amino acetic acids, amino acids, glycine, alanine, carboxylic acids, polyamines, ammonia based compounds, quaternary ammonium compounds, inorganic acids, compounds with both carboxylic and amino functions, ethylenediaminetetraacetic acid, diethylene triamine pentaacetic acid, and any mixtures thereof.
10. The concentrate of claim 1 , wherein corrosion inhibitor is selected from the group consisting of benzotriazole and its derivatives, tolyl triazole and its derivatives, and azoles.
11. The method of claim 1 , wherein said concentrate is diluted with said water so that said abrasive, said complexing agent, and said corrosion inhibitor are present in amounts in said chemical mechanical polishing slurry that are at least five times less than in said concentrate.
12. The method of claim 1 , wherein said concentrate is diluted with said water so that said abrasive, said complexing agent, and said corrosion inhibitor are present in amounts in said chemical mechanical polishing slurry that are at least ten times less than in said concentrate.
13. The method of claim 1 , wherein said concentrate is diluted with said water so that said abrasive, said complexing agent, and said corrosion inhibitor are present in amounts in said chemical mechanical polishing slurry that are at least twenty times less than in said concentrate.
14. A method of removing a copper layer from a substrate, comprising the step of contacting the copper layer with the chemical mechanical polishing slurry of claim 1 , wherein the chemical mechanical polishing slurry removes said copper layer at a rate that is at least 75% of a peak removal rate of the chemical mechanical polishing slurry.