Functionalized Carbon CMP Slurry for Planar Metal and Nitride Removal
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Solution Overview
Problem
Conventional chemical mechanical polishing compositions for tungsten and metal nitrides often cause recessing and non-planarity issues due to excessive chemical etching, leading to electrical contact problems and increased device non-planarity.
Innovation Solution
A chemical mechanical polishing composition using functionalized carbon-based particles with oxygen-containing functional groups and sp3-containing structures, which react with peroxy moieties, operates without Fenton's catalyst, and is stable at higher pH levels, providing effective removal rates for metals and metal nitrides while minimizing etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional polishing compositions use Fenton's catalyst or reagent in harsh oxidizing environment, then tungsten removal rate is improved, but excessive chemical etching occurs causing recessing and non-planarity
Solution Approach 1:
The invention changes the chemical environment parameters by using a basic pH composition (pH 9-11) instead of harsh oxidizing acidic environment, and employs hydrogen peroxide instead of Fenton's catalyst, fundamentally altering the chemical reaction conditions to reduce excessive etching while maintaining removal rate
Solution Approach 2:
The invention replaces the chemical etching mechanism (Fenton's catalyst) with a mechanical abrasion mechanism using silica abrasive particles, where the polishing action is dominated by mechanical removal rather than chemical dissolution, thus preventing recessing and keyholing
2Productivity
If conventional polishing compositions use alumina or silica fine particles with Fenton's catalyst, then metal removal rate is improved, but chemical etching causes recessed tungsten vias and keyholing
Solution Approach 1:
The invention changes the pH parameter from acidic to basic (pH 9-11), which fundamentally alters the chemical behavior of the polishing composition, reducing the chemical etching that causes recessing and keyholing while maintaining effective metal removal through mechanical abrasion
Solution Approach 2:
The invention converts the harmful chemical etching effect into a beneficial mechanical abrasion process by using silica particles that physically remove metal through friction and abrasion, transforming the harmful chemical dissolution into a controlled mechanical removal mechanism
3Productivity
If polishing composition operates at low pH with Fenton's reagent, then tungsten removal rate is improved, but interlevel dielectric erosion increases
Solution Approach 1:
The invention changes the pH parameter from low (acidic) to high (basic, pH 9-11), which significantly reduces the chemical reactivity toward the interlevel dielectric material while maintaining tungsten removal capability through mechanical abrasion with silica particles
Solution Approach 2:
The invention introduces silica abrasive particles as an intermediary mechanism for metal removal, where the silica particles mediate the removal process through mechanical abrasion rather than direct chemical etching, thereby protecting the interlevel dielectric from erosion
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 achieves enhanced removal rates for cobalt, copper, molybdenum, tungsten, titanium nitride, and tantalum nitride layers with improved selectivity to dielectric layers, reducing static etch rates and maintaining device planarity.
Implementation Method 1
the functionalized carbon-based particles having oxygen-containing functional groups react with a peroxy moiety to increase oxygen to carbon atomic ratio on the functionalized carbon-based particles
Implementation Method 2
functionalized carbon-based particles having oxygen-containing functional groups react with a peroxy moiety to increase oxygen to carbon atomic ratio on the functionalized carbon-based particles, the functionalized carbon-based particles containing at least 10 weight percent of an sp3-containing structure
Data Source
AI summary
The invention provides a chemical mechanical polishing solution for metal and metal nitride substrates. The polishing solution includes a solvent and functionalized carbon-based particles having oxygen-containing functional groups. The functionalized carbon-based particles having oxygen-containing functional groups react with a peroxy moiety to increase oxygen to carbon atomic ratio on the functionalized carbon-based particles. The functionalized carbon-based particles contain at least 10 weight percent of an sp3-containing structure, the functionalized carbon-based particles include at least 0.01 atomic percent oxygen and a surface of the functionalized carbon-based particles has an atomic oxygen to carbon ratio of at least 0.01.