MIXED ABRASIVE TUNGSTEN CMP COMPOSITION
First Claim
1. A chemical mechanical polishing composition comprising:
- a water based liquid carrier;
a first colloidal silica abrasive dispersed in the liquid carrier, the first colloidal silica abrasive having a permanent positive charge of at least 10 mV;
a second colloidal silica abrasive dispersed in the liquid carrier, the second colloidal silica abrasive having a permanent positive charge of at least 10 mV; and
an iron containing accelerator;
wherein an average particle size of the second colloidal silica abrasive is at least 20 nanometers greater than an average particle size of the first colloidal silica abrasive.
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Accused Products
Abstract
A chemical mechanical polishing composition for polishing a substrate having a tungsten layer includes a water based liquid carrier, first and second colloidal silica abrasives dispersed in the liquid carrier, and an iron containing accelerator. The first colloidal silica abrasive and the second colloidal silica abrasive each have a permanent positive charge of at least 10 mV. An average particle size of the second silica abrasive is at least 20 nanometers greater than an average particle size of the first silica abrasive. A method for chemical mechanical polishing a substrate including a tungsten layer is further disclosed. The method may include contacting the substrate with the above described polishing composition, moving the polishing composition relative to the substrate, and abrading the substrate to remove a portion of the tungsten from the substrate and thereby polish the substrate.
17 Citations
19 Claims
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1. A chemical mechanical polishing composition comprising:
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a water based liquid carrier; a first colloidal silica abrasive dispersed in the liquid carrier, the first colloidal silica abrasive having a permanent positive charge of at least 10 mV; a second colloidal silica abrasive dispersed in the liquid carrier, the second colloidal silica abrasive having a permanent positive charge of at least 10 mV; and an iron containing accelerator; wherein an average particle size of the second colloidal silica abrasive is at least 20 nanometers greater than an average particle size of the first colloidal silica abrasive. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 17, 18, 19)
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12. A method of chemical mechanical polishing a substrate including a tungsten layer, the method comprising:
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(a) contacting the substrate with a polishing composition comprising; (i) a water based liquid carrier; (ii) a first colloidal silica abrasive dispersed in the liquid carrier, the first colloidal silica abrasive having a permanent positive charge of at least 10 mV; (iii) a second colloidal silica abrasive dispersed in the liquid carrier, the second colloidal silica abrasive having a permanent positive charge of at least 10 mV; and (iv) an iron containing accelerator; wherein an average particle size of the second colloidal silica abrasive is at least 20 nanometers greater than an average particle size of the first colloidal silica abrasive; (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. - View Dependent Claims (13, 14, 15, 16)
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Specification