Chemical mechanical polishing method for tungsten

Patent metadata

Field	Value
Publication number	US-2021002512-A1
Application number	US-202017023694-A
Country	US
Kind code	A1
Filing date	Sep 17, 2020
Priority date	May 3, 2018
Publication date	Jan 7, 2021
Grant date	—

Abstract

A process for chemical mechanical polishing a substrate containing tungsten is disclosed to reduce corrosion rate and inhibit dishing of the tungsten and erosion of underlying dielectrics. The process includes providing a substrate; providing a polishing composition, containing, as initial components: water; an oxidizing agent; nonionic polyacrylamide; a dicarboxylic acid, a source of iron ions; a colloidal silica abrasive having a negative zeta potential; and, optionally, a pH adjusting agent; providing a chemical mechanical polishing pad, having a polishing surface; creating dynamic contact at an interface between the polishing pad and the substrate; and dispensing the polishing composition onto the polishing surface at or near the interface between the polishing pad and the substrate; wherein some of the tungsten is polished away from the substrate, corrosion rate is reduced, dishing of the tungsten is inhibited as well as erosion of dielectrics underlying the tungsten.

First claim

1 - 8 . (canceled)

9 . A composition for chemical mechanical polishing tungsten consisting of, as initial components:
water;
an oxidizing agent;
nonionic polyacrylamide
a colloidal silica abrasive having a negative zeta potential;
a dicarboxylic acid, salt thereof or mixtures thereof,
a source of iron (III) ions; and,
optionally, a pH adjusting agent.

10 . The composition of claim 9 , wherein the chemical mechanical polishing composition for tungsten consists of, as initial components:
the water; 0.01 to 10 wt % of the oxidizing agent, wherein the oxidizing agent is hydrogen peroxide; 20 to 320 ppm of the nonionic polyacrylamide; 0.01 to 10 wt % of the colloidal silica abrasive having a negative zeta potential; 100 to 1,400 ppm of the dicarboxylic acid, salt thereof or mixtures thereof, wherein the dicarboxylic acid, salt thereof or mixtures thereof is malonic acid, salt thereof or mixtures thereof; 100 to 1,000 ppm of the source of iron (III) ions, wherein the source of iron (III) ions is ferric nitrate nonahydrate; and optionally the pH adjusting agent; wherein the chemical mechanical polishing composition has a pH from 1 to 7.

11 . The composition of claim 9 , wherein the chemical mechanical polishing composition for tungsten consists of, as initial components:
the water; 1 to 3 wt % of the oxidizing agent, wherein the oxidizing agent is hydrogen peroxide; 50 to 320 ppm of the nonionic polyacrylamide; 0.2 to 2 wt % of the colloidal silica abrasive having a negative zeta potential; 120 to 1,350 ppm of the dicarboxylic acid, salt thereof or mixtures thereof, wherein the dicarboxylic acid, salt thereof or mixtures thereof is malonic acid, salt thereof or mixtures thereof; 250 to 400 ppm of the source of iron (III) ions, wherein the source of iron (III) ions is ferric nitrate nonahydrate; and optionally the pH adjusting agent; wherein the chemical mechanical polishing composition has a pH from 2 to 2.5.

Assignees

• Rohm & Haas Elect Materials Cmp Holdings Inc

Inventors

• Ho Lin-Chen
• Tsai Wei-Wen

Classifications

• H10P52/403 Primary

  of conductive or resistive materials · CPC title

• H10W20/062

  by smoothing of conductive parts, e.g. by planarisation · CPC title

• B24B37/042 Primary

  operating processes therefor · CPC title

• B24B57/02

  for feeding of fluid, sprayed, pulverised, or liquefied grinding, polishing or lapping agents · CPC title

• B24B37/20

  Lapping pads for working plane surfaces · CPC title