Reduction in large particle counts in polishing slurries
The present disclosure provides a method for reducing large particle counts (LPCs) in copper chemical mechanical polishing slurry by way of using high purity removal rate enhancer (RRE) in the slurry. The conductivity of the RRE in deionized water solutions correlates very strongly with the number of LPCs in the RRE, and thus in a slurry using the RRE.
1. A copper chemical mechanical polishing composition, comprising:
glycine, present in an amount up to 20 wt %, based on the weight of the composition;
an azole corrosion inhibitor
an abrasive;
wherein said glycine has a conductivity C in deionized water, and wherein glycine obeys the following inequality:
C≦a*W+b,
wherein W is the wt % of the glycine, based on the total weight of the composition, wherein 0.0005<a<0.0025, and wherein 0.0005<b<0.0025,
wherein said composition has a large particle count, wherein said large particle count is defined by the number of particles per milliliter of the composition having a size greater than 0.56 micrometers,
and wherein said conductivity C and said large particle count have a positive correlation, such that the lower said conductivity, the lower said large particle count.
2. The composition of claim 1 , wherein the conductivity C is less than 0.0525 milliSiemens per centimeter.
3. The composition of claim 1 , wherein the corrosion inhibitor is selected from the group consisting of benzotriazole, derivatives of benzotriazole, tolyl triazole, derivatives of tolyl triazole, and any combinations thereof.
4. The composition 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 mixtures thereof.
5. The composition of claim 1 , further comprising an oxidizer selected from the group consisting of hydrogen peroxide, ammonium persulfate, silver nitrate , ferric nitrates, ferric chloride, per acid, per salts, ozone water, potassium ferricyanide, potassium dichromate, potassium iodate, potassium bromate, vanadium trioxide, hypochlorous acid, sodium hypochlorite, potassium hypochlorite, calcium hypochlorite, magnesium hypochlorite, ferric nitrate, KMnO 4 , other inorganic or organic peroxides, and any mixtures thereof.
6. The composition of claim 1 , further comprising an additional ingredient selected from the group consisting of surfactant, biocide, surface finisher, pH adjuster, defect reduction agent, or any mixtures thereof.