Composition for tungsten buffing
AssigneeCabot Microelectronics Corporation
InventorsLin Fu, Jeffrey Dysard, Steven Grumbine
Life of this patent
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Abstract
A chemical mechanical polishing composition for polishing a substrate having a tungsten layer includes a water based liquid carrier and colloidal silica abrasive particles dispersed in the liquid carrier. The colloidal silica abrasive particles have a permanent positive charge of at least 6 mV. About 30 percent or more of the colloidal silica abrasive particles include three or more aggregated primary particles.
Claims25
A chemical mechanic polishing composition comprising:
- a water based liquid carrier;
- colloidal silica abrasive particles dispersed in the liquid carrier, wherein 30 percent or more of the colloidal silica abrasive particles include three or more aggregated primary particles, the colloidal silica abrasive particles having a permanent positive charge of at least 6 mV;
- an iron containing accelerator;
- and
- an oxidizer.
A chemical mechanic polishing composition comprising:
- a water based liquid carrier;
- colloidal silica abrasive particles dispersed in the liquid carrier, the colloidal silica abrasive particles having a permanent positive charge of at least 6 mV, wherein 30 percent or more of the colloidal silica abrasive particles include three or more aggregated primary particles;
- and
- an oxidizer;
- wherein the polishing composition includes from about 1 weight percent to about 4 weight percent of the colloidal silica abrasive particles.
A method of chemical mechanical polishing a substrate including tungsten and silicon dioxide layers, the method comprising:
- (a) contacting the substrate with a polishing composition comprising:
- (i) a water based liquid carrier;
- (ii) colloidal silica abrasive particles dispersed in the liquid carrier, wherein 30 percent or more of the colloidal silica abrasive particles include three or more aggregated primary particles, the colloidal silica abrasive particles having a permanent positive charge of at least 6 mV;
- (iii) an iron containing accelerator;
- and
- (iv) an oxidizer;
- (b) moving the polishing composition relative to the substrate;
- and
- (c) abrading the substrate to remove a portion of the tungsten from the substrate and thereby polish the substrate.
Dependencies are inferred from the claim text.