Cationic Polymer Ceria Slurry for High-Rate Oxide CMP
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Solution Overview
Problem
Chemical-mechanical polishing compositions for dielectric substrates face challenges in achieving high removal rates while minimizing trench loss, as existing ceria abrasives tend to increase trench loss with higher removal rates.
Innovation Solution
A chemical-mechanical polishing composition comprising wet-process ceria, a water-soluble cationic polymer or copolymer, an aromatic carboxylic acid or heteroaromatic carboxylic acid, and water, with a pH of 3 to 6, which includes a cross-linked cationic polymer prepared from melamine or its derivatives and an aldehyde, and an aromatic carboxylic acid like picolinic acid, to enhance removal rates while reducing trench loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ceria abrasives are used to increase dielectric removal rates, then productivity is improved, but trench loss increases
Solution Approach 1:
The patent changes the chemical parameters of the polishing composition by introducing a cationic polymer and aromatic carboxylic acid at controlled pH (3-6), which modifies the chemical interaction between the ceria abrasive and the dielectric material. This chemical modification allows for enhanced removal rates while controlling the polishing mechanism to reduce trench loss
Solution Approach 2:
The patent creates a composite polishing system combining ceria abrasive particles with a cationic polymer matrix and aromatic carboxylic acid additives. This composite composition works synergistically to achieve both high removal rates and reduced trench loss, as the polymer and acid components modulate the polishing action of the ceria particles
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition effectively increases dielectric removal rates while minimizing trench loss, as demonstrated by the inclusion of a water-soluble cationic polymer like methylated melamine-formaldehyde copolymer, which optimizes substrate planarization and reduces defects.
Implementation Method 1
The chemical components chemically modify at least some of the substrate material to promote physical removal by the combination of the abrasive and the polishing pad
Implementation Method 2
The chemical components chemically modify at least some of the substrate material to promote physical removal by the combination of the abrasive and the polishing pad
Implementation Method 3
contacting the surface with a rotating polishing pad saturated with the polishing composition
Implementation Method 4
the pressure exerted by the polishing pad is directed primarily at the high areas
Data Source
Figure 1
AI summary
The invention provides a chemical mechanical polishing composition comprising (a) wet process ceria, (b) a water soluble cationic polymer or copolymer, (c) an aromatic carboxylic acid or heteroaromatic carboxylic acid, and (d) water, wherein the polishing composition has a pH of about 3 to about 6. 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.