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Cmp compositions selective for oxide and nitride with high removal rate and low defectivity

a composition and oxide technology, applied in the direction of polishing compositions, lapping machines, manufacturing tools, etc., can solve the problems of overpolishing of the substrate surface, formation of recesses in the sti features, other topographical defects, etc., and achieve the effect of reducing the cost of the devi

Active Publication Date: 2014-11-27
CMC MATERIALS INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The invention is a chemical-mechanical polishing composition that includes ceria abrasive, an ionic polymer, and water. The composition has a pH of about 1 to about 4.5. The method involves contacting a substrate with a polishing pad and the polishing composition, moving the pad and composition relative to the substrate, and abrading the substrate to polish it. The technical effect is a improved polishing process with reduced damage to the substrate.

Problems solved by technology

However, polishing STI substrates with conventional polishing media and abrasive-containing polishing compositions has been observed to result in overpolishing of the substrate surface or the formation of recesses in the STI features and other topographical defects such as microscratches on the substrate surface.
Dishing is undesirable because dishing of substrate features may detrimentally affect device fabrication by causing failure of isolation of transistors and transistor components from one another, thereby resulting in short-circuits.
Additionally, overpolishing of the substrate may also result in oxide loss and exposure of the underlying oxide to damage from polishing or chemical activity, which detrimentally affects device quality and performance.

Method used

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  • Cmp compositions selective for oxide and nitride with high removal rate and low defectivity
  • Cmp compositions selective for oxide and nitride with high removal rate and low defectivity
  • Cmp compositions selective for oxide and nitride with high removal rate and low defectivity

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0056]This example demonstrates the effect of a polyethylene glycol dicarboxylic acid on silicon oxide removal rates and silicon oxide versus silicon nitride and polysilicon selectivity.

[0057]Separate substrates comprising TEOS-coated silicon, silicon nitride-coated silicon, and polysilicon-coated silicon were polished with two different polishing compositions, i.e., Polishing Compositions 1A and 1B. Each of the polishing compositions contained 0.4 wt. % of wet-process ceria in water at a pH of 3.6. Polishing Composition 1A (invention) further contained 0.1 wt. % of a polyethylene glycol dicarboxylic acid having a molecular weight of about 600. Polishing Composition 1B (comparative) further contained a polyacrylic acid partially esterified with polyethylene glycol.

[0058]Following polishing, the removal rates for silicon oxide, silicon nitride, and polysilicon were determined, and the selectivities for silicon oxide versus silicon nitride and polysilicon were calculated. The removal ...

example 2

[0060]This example demonstrates the effect of a polyethylene glycol dicarboxylic acid on nitride loss and dishing in the polishing of patterned silicon nitride substrates.

[0061]Three separate patterned substrates comprising 100 μm silicon nitride features on silicon oxide-coated substrates were polished with three different polishing compositions, i.e., Polishing Compositions 2A-2C. Each of the polishing compositions contained 0.4 wt. % wet-process ceria in water at a pH of 3.6. Polishing Composition 2A (control) did not contain any polymer. Polishing Compositions 2B and 2C (invention) further contained polyethylene glycol dicarboxylic acids having molecular weights of about 3400 and 8000, respectively.

[0062]Following polishing, the silicon nitride loss and dishing were determined. The silicon nitride loss and dishing are expressed relative to the silicon nitride loss and dishing observed for Polishing Composition 2B. The results are set forth in Table 2.

TABLE 2Polishing Composition...

example 3

[0064]This example compares silicon oxide removal rates and silicon oxide versus silicon nitride and polysilicon selectivity observed with a polishing composition comprising a polyethylene glycol dicarboxylic acid with silicon oxide removal rates and silicon oxide versus silicon nitride and polysilicon selectivity observed with polishing compositions comprising neutral water-soluble polymers containing ether linkages in the polymer backbones.

[0065]Separate substrates comprising TEOS-coated silicon, silicon nitride-coated silicon, and polysilicon-coated silicon were polished with four different polishing compositions, i.e., Polishing Compositions 3A-3D. Each of the polishing compositions contained 0.4 wt. % of wet-process ceria in water at a pH of 3.7. Polishing Composition 3A (control) did not further comprise any polymer. Polishing Composition 3B (invention) further comprised 0.1 wt. % of a polyethylene glycol dicarboxylic acid having a molecular weight of about 600. Polishing Comp...

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Abstract

The invention provides a chemical-mechanical polishing composition containing a ceria abrasive, an ionic polymer of formula I:wherein X1 and X2, Z1 and Z2, R2, R3, and R4, and n are as defined herein, and water, wherein the polishing composition has a pH of about 1 to about 4.5. The invention further provides a method of chemically-mechanically polishing a substrate with the inventive chemical-mechanical polishing composition. Typically, the substrate contains silicon oxide, silicon nitride, and / or polysilicon.

Description

BACKGROUND OF THE INVENTION[0001]Compositions and methods for planarizing or polishing the surface of a substrate are well known in the art. Polishing compositions (also known as polishing slurries) typically contain an abrasive material in a liquid carrier and are applied to a surface by contacting the surface with a polishing pad saturated with the polishing composition. Typical abrasive materials include silicon dioxide, cerium oxide, aluminum oxide, zirconium oxide, and tin oxide. Polishing compositions are typically used in conjunction with polishing pads (e.g., a polishing cloth or disk). Instead of, or in addition to, being suspended in the polishing composition, the abrasive material may be incorporated into the polishing pad.[0002]As a method for isolating elements of a semiconductor device, a great deal of attention is being directed towards a shallow trench isolation (STI) process where a silicon nitride layer is formed on a silicon substrate, shallow trenches are formed ...

Claims

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Application Information

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IPC IPC(8): C09G1/02B24B37/04
CPCB24B37/044C09G1/02C09G1/16
Inventor DOCKERY, KEVIN P.JIA, RENHEDYSARD, JEFFREY
Owner CMC MATERIALS INC