CMP Slurry Selective Polishing Cobalt Zirconium Oxide Poly-Silicon
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Solution Overview
Problem
Current chemical mechanical polishing (CMP) methods face complexity in selectively polishing cobalt, zirconium oxide, and poly-silicon films over silicon dioxide, requiring unique compositions and settings for each material, which is challenging in advanced logic nodes ≤10 nm where high-k dielectric films like zirconium oxide are integrated with cobalt and silicon dioxide.
Innovation Solution
A CMP method using a composition containing water, colloidal silica abrasive, a cobalt chelating agent, a corrosion inhibitor, and a benzyltrialkyl quaternary ammonium compound, with a pH greater than 7, and free of oxidizing agents, to selectively polish cobalt, zirconium oxide, and poly-silicon over silicon dioxide, achieving tunable removal rates and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CMP processes use unique polishing compositions and settings for each material type, then polishing effectiveness for individual materials is improved, but process complexity increases
Solution Approach 1:
The patent develops a universal polishing composition containing colloidal silica abrasive particles, cobalt chelating agent, corrosion inhibitor, and benzyltrialkyl quaternary ammonium compound that can effectively polish multiple materials (cobalt, zirconium oxide, poly-silicon, and silicon dioxide) with tunable removal rates and selectivity, eliminating the need for multiple material-specific compositions and processes
2Productivity
If oxidizing agents are used in polishing composition, then removal rate is improved, but selectivity between materials deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the polishing composition by using a basic pH environment (pH > 7) with specific chelating agents and corrosion inhibitors instead of oxidizing agents, enabling selective removal of cobalt, zirconium oxide, and poly-silicon over silicon dioxide through controlled chemical reactions that do not compromise material selectivity
3Manufacturing precision
If polishing composition contains multiple functional components, then polishing performance is improved, but composition complexity increases
Solution Approach 1:
The patent merges multiple functional components into a single integrated polishing composition: colloidal silica abrasive particles for mechanical removal, cobalt chelating agent for selective chemical interaction with cobalt, corrosion inhibitor for protecting silicon dioxide, and benzyltrialkyl quaternary ammonium compound for enhancing polishing performance, all working synergistically in one formulation
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 method provides selective removal rates for cobalt, zirconium oxide, and poly-silicon over silicon dioxide, enhancing planarization and integration of complex films in advanced logic nodes, with demonstrated removal rates and selectivity suitable for advanced semiconductor processing.
Implementation Method 1
a colloidal silica abrasive
Implementation Method 2
a cobalt chelating agent
Implementation Method 3
a corrosion inhibitor
Data Source
AI summary
A process for chemical mechanical polishing a substrate containing cobalt, zirconium oxide, poly-silicon and silicon dioxide, wherein the cobalt, zirconium, and poly-silicon removal rates are selective over silicon dioxide. The chemical mechanical polishing composition includes water, a benzyltrialkyl quaternary ammonium compound, cobalt chelating agent, corrosion inhibitor, colloidal silica abrasive, optionally a biocide and optionally a pH adjusting agent, and a pH greater than 7, and the chemical mechanical polishing compositions are free of oxidizing agents.