Tungsten CMP Composition for Etching Inhibition Without Rate Loss
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Solution Overview
Problem
Existing compositions for inhibiting tungsten etching during chemical mechanical polishing (CMP) are ineffective in preventing erosion of tungsten within trenches and can reduce polishing rates to unacceptable levels.
Innovation Solution
A composition comprising inorganic abrasive particles, specifically methylbenzethonium, methylbenzethonium, or benzethonium salts, and an aqueous medium with a pH range of 5.0 to 11.0, which inhibits tungsten etching while maintaining stable formulation and polishing rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high concentrations of known inhibitors are used to prevent tungsten etching, then tungsten erosion is reduced, but polishing rates decrease to unacceptable levels
Solution Approach 1:
The patent changes the chemical parameters of the inhibition system by introducing a specific multifunctional inhibitor with amino and hydroxyl groups that works effectively at lower concentrations (0.01-5 wt%) compared to prior art, thereby maintaining polishing rates while preventing tungsten erosion. The pH range is also optimized to 5-11 for effective performance.
Solution Approach 2:
The patent uses a composite inhibitor system combining multiple functional groups (amino and hydroxyl) within the same molecular structure, creating a multifunctional compound that provides both etching inhibition and erosion prevention. This composite approach allows effective tungsten protection at lower concentrations, avoiding the productivity loss associated with high concentrations of single-function inhibitors.
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 inhibits tungsten etching, prevents erosion during CMP, and maintains stable polishing rates, ensuring improved performance and ease of application.
Implementation Method 1
CMP utilizes the interplay of chemical and mechanical action to achieve the planarity of the to-be-polished surfaces. Mechanical action is usually carried out by a polishing pad which is typically pressed onto the to-be-polished surface
Implementation Method 2
the compounds capable of etching tungsten convert tungsten into a soft oxidized film that is capable of removal by mechanical abrasion
Implementation Method 3
U.S. Pat. No. 6,273,786 B1 describes methods and compositions comprising tungsten corrosion inhibitors to protect tungsten that include phosphates, polyphosphates and silicates
Implementation Method 4
The compounds capable of etching tungsten convert tungsten into a soft oxidized film that is capable of removal by mechanical abrasion
Data Source
AI summary
The presently claimed invention relates to compositions and methods for inhibition of etching. The presently claimed invention particularly relates to a composition and methods for inhibition of tungsten etching.