POLISHING SLURRY AND METHOD OF POLISHING USING THE SAME
Disclosed are a polishing slurry used in a polishing process of tungsten and a method of polishing using the same. The slurry includes an abrasive for performing polishing and an oxidation promoting agent for promoting the formation of an oxide. The abrasive includes titanium oxide particles.
1 . A slurry for polishing tungsten, comprising:
an abrasive for performing the polishing and an oxidation promoting agent for promoting formation of an oxide,
the abrasive comprising particles of titanium oxide.
2 . The slurry of claim 1 , wherein an amount of the titanium oxide exceeds approximately 0.2 wt % and is approximately 10 wt % or less based on the total amount of the slurry.
3 . The slurry of claim 1 , wherein the oxidation promoting agent is at least one selected from the group consisting of ferric nitrate, potassium ferricyanide, iron chloride, iron sulfate, iron fluoride, iron bromide, copper chloride, copper fluoride, and copper bromide, and
an amount of the oxidation promoting agent is from approximately 0.002 wt % to approximately 0.1 wt % based on the total amount of the slurry.
4 . The slurry of claim 3 , wherein the amount of titanium oxide is from approximately 0.7 wt % to approximately 5 wt % based on the total amount of the slurry.
5 . The slurry of claim 4 , wherein the amount of titanium oxide is from approximately 1.0 wt % to approximately 2.0 wt % based on the total amount of the slurry.
6 . The slurry of claim 3 , wherein the amount of the oxidation promoting agent is from approximately 0.01 wt % to approximately 0.1 wt % based on the total amount of the slurry.
7 . The slurry of claim 3 , wherein the amount of the oxidation promoting agent is from approximately 0.05 wt % to approximately 0.1 wt % based on the total amount of the slurry.
8 . The slurry of claim 3 , wherein pH of the slurry is controlled to from approximately 1 to approximately 4.
9 . The slurry of claim 3 , wherein the slurry further comprises at least one oxidizing agent for forming an oxide, selected from the group consisting of hydrogen peroxide, carbamide peroxide, ammonium persulfate, ammonium thiosulfate, sodium hypochlorite, sodium periodate, sodium persulfate, potassium iodate, potassium perchlorate, and potassium persulfate,
and wherein, an amount of the oxidizing agent is from approximately 0.5 wt % to less than approximately 5.0 wt % based on the total amount of the slurry.
10 . The slurry of claim 9 , wherein the amount of the oxidizing agent is from approximately 0.5 wt % to approximately 2 wt % based on the total amount of the slurry.
11 . The slurry of claim 9 , wherein the amount of the oxidizing agent is from approximately 1 wt % to approximately 2 wt % based on the total amount of the slurry.
12 . The slurry of claim 3 , further comprising at least one selectivity improving agent selected from the group consisting of polyvinyl pyrrolidone, vinyl pyridine and vinyl pyrrolidone.
13 . The slurry of claim 12 , wherein an amount of the selectivity improving agent is from approximately 0.05 wt % to less than approximately 3.0 wt % based on the total amount of the slurry.
14 . The slurry of claim 13 , wherein the amount of the selectivity improving agent is from approximately 0.05 wt % to approximately 1.0 wt % based on the total amount of the slurry.
15 . The slurry of claim 13 , wherein the amount of the selectivity improving agent is from approximately 0.05 wt % to approximately 0.1 wt % based on the total amount of the slurry.
16 . The slurry of claim 3 , wherein the particles of titanium oxide is formed to have a crystalline phase and a mean primary particle size is from approximately 10 nm to approximately 100 nm.
17 . A slurry for polishing tungsten comprising particles of titanium oxide as an abrasive for performing polishing, the particles of titanium oxide having a crystalline phase and at least a portion of the particles of titanium oxides having an anatase crystalline phase, the particles of titanium oxide having a mean primary particle size of from approximately 10 nm to approximately 100 nm.
18 . The slurry of claim 17 , wherein the particles of titanium oxide has a polyhedron shape.
19 . The slurry of claim 18 , wherein the particles of titanium oxide have the mean primary particle size of from approximately 15 nm to less than approximately 50 nm.
20 . The slurry of claim 17 , wherein the particles of titanium oxide comprises the anatase crystalline phase and a rutile crystalline phase, and an amount of the anatase crystalline phase exceeds approximately 50 based on 100 of a total of the anatase and the rutile crystalline phases.
21 - 31 . (canceled)