Multi-step methods for chemical mechanical polishing silicon dioxide and silicon nitride

A two step method for polishing silica and silicon nitride on a semiconductor wafer comprising the steps of:

• planarizing the silica with an inhibitive slurry;
• detecting a first endpoint and stopping the planarization;
• clearing the silica with a selective slurry;
• and
• detecting a second endpoint and stopping the clearing.

A multi-step method for polishing silica and silicon nitride on a semiconductor wafer comprising:

• planarizing the silica with a first aqueous composition comprising by weight percent 0.01 to 5 carboxylic acid polymer, 0.02 to 6 abrasive, 0.01 to 10 polyvinylpyrrolidone, 0 to 5 cationic compound, 0 to 1 phthalic acid and salts, 0 to 5 zwitterionic compound and balance water, wherein the polyvinylpyrrolidone has an average molecular weight between 100 grams/mole to 1,000,000 grams/mole;
• detecting a first endpoint and stopping the planarization;
• clearing the silica with a second aqueous composition comprising by weight percent 0.001 to 1 quaternary ammonium compound, 0.001 to 1 phthalic acid and salts thereof, 0.01 to 5 carboxylic acid polymer, 0.01 to 5 abrasive and balance water;
• and
• detecting a second endpoint and stopping the clearing.