Polishing compositions and methods for selectively polishing silicon nitride over silicon oxide films
AssigneeFujifilm Planar Solutions, LLC
InventorsAbhudaya Mishra, Luling Wang
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Abstract
Stable aqueous polishing compositions that can selectively polish silicon nitride (SiN) films and nearly stop (or polish at very low rates) on silicon oxide films are provided herein. The compositions comprise an anionic abrasive, a nitride removal rate enhancer containing a carboxyl or carboxylate group, water, and optionally, an anionic polymer. The synergistic combination of anionic (negatively charged) abrasives and the nitride removal rate enhancer provide beneficial charge interactions with the dielectric films during CMP, a high SiN rate and selectivity enhancement (over oxide), and stable colloidal dispersed slurries.
Claims24
A polishing method, comprising:
- applying a polishing composition to a substrate having silicon nitride on its surface;
- and
- removing at least a portion of the silicon nitride from the substrate at a first rate, by bringing a pad into contact with the substrate and moving the pad in relation to the substrate, wherein the composition comprises:
- a) an anionic abrasive;
- b) a nitride removal rate enhancer comprising a carboxylic acid or a carboxyl/carboxylate group for increasing silicon nitride rates;
- c) water;
- and
- (d) optionally, an anionic polymer;
- wherein the polishing composition has a pH of about 2 to about 6.5.
Dependencies are inferred from the claim text.