Method for Chemical-Mechanical Planarization of Copper
Method for polishing copper by chemical-mechanical planarization. The method of the present invention includes dissolving MoO 3 in an oxidizing agent and deionized water to form a first slurry; filtering the first slurry; adding supplemental ceramic/metal oxide nano-particles to the first slurry after filtering, forming an aqueous slurry; introducing the aqueous slurry between the copper and a polishing pad; and, polishing the copper by moving the polishing pad and the copper relative to one another.
1 . A method for planarizing copper, comprising:
dissolving MoO 3 in an oxidizing agent and deionized water to form a first slurry;
filtering the first slurry;
adding supplemental ceramic/metal oxide nano-particles to the first slurry after filtering, forming an aqueous slurry;
introducing the aqueous slurry between the copper and a polishing pad; and
polishing the copper by moving the polishing pad and the copper relative to one another.
2 . The method of claim 1 , wherein the dissolving comprises dissolving about 0.1% to up to 1% by weight of MoO 3 to form the first slurry.
3 . The method of claim 1 , wherein the dissolving comprises dissolving about 0.1% to about 5% by weight of MoO 3 to form the first slurry.
4 . The method of claim 1 , further comprising applying a pressure between the copper and the polishing pad, the pressure being in a range of between about 4 to about 6.3 psi.
5 . The method of claim 1 , wherein the dissolving comprises dissolving MoO 3 in the oxidizing agent selected from the group consisting of hydrogen peroxide, ferric nitrate, potassium iodate, nitric acid, potassium permanganate, potassium persulfate, ammonium persulfate, potassium periodate, and hydroxylamine.
6 . The method of claim 1 , wherein the dissolving comprises dissolving MoO 3 in the oxidizing agent, the oxidizing agent being ferric nitrate.
7 . The method of claim 1 , wherein the polishing occurs at a polishing rate of at least 600 nm/min.
8 . The method of claim 1 , wherein the polishing achieves a dissolution rate of no more than about 50 nm/min.
9 . The method of claim 1 , wherein the adding comprises forming the aqueous slurry with a pH in a range from about 2.9 to about 2.6.
10 . The method of claim 1 , further comprising adding a complexing agent and a corrosion inhibitor to the first slurry.
11 . The method of claim 10 , further comprising adding a surfactant to the first slurry.
12 . The method of claim 11 , wherein the adding the surfactant comprises adding dodecyl benzene sulfonic acid and salts thereof.
13 . The method of claim 1 , wherein the filtering comprises using a 100 nm filter.
14 . The method of claim 1 , wherein the dissolving MoO 3 comprises dissolving MoO 3 consisting essentially of nano-particles.
15 . The method of claim 1 , wherein the introducing comprises introducing the aqueous slurry at a flow rate of between about 60 ml/min. and about 200 ml/min.
16 . A method for polishing copper by chemical-mechanical planarization, comprising:
providing a high polish rate slurry comprising dissolved MoO 3 and an oxidizing agent;
polishing copper with the high polish rate slurry;
providing a low polish rate slurry comprising dissolved MoO 3 , an oxidizing agent, and a corrosion inhibitor; and
additionally polishing the copper with the low polish rate slurry.