CMP Slurry Chelation for Ruthenium Removal Rate
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Solution Overview
Problem
The chemical inertness and high hardness of transition metal elements like ruthenium (Ru) make them difficult to process, particularly in chemical mechanical polishing (CMP) processes, which is necessary for advanced semiconductor manufacturing.
Innovation Solution
A CMP slurry composition is developed that includes a chelator, such as a thiol or thiolether compound, to enhance the removal rate of ruthenium by forming coordinate covalent bonds, allowing for effective polishing of ruthenium-based materials during the CMP process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CMP processes are used on ruthenium, then the polishing process is simple, but the removal rate is extremely low due to ruthenium's chemical inertness and high hardness
Solution Approach 1:
A chelating agent is introduced as an intermediary substance in the CMP slurry to mediate the interaction between the ruthenium surface and the abrasive particles. The chelating agent forms coordinate covalent bonds with ruthenium atoms, creating a chemically modified surface layer that is significantly more susceptible to mechanical removal by the abrasive, thereby resolving the contradiction between simplicity and removal rate
Solution Approach 2:
The chemical composition parameters of the CMP slurry are changed by incorporating specific chelating agents (such as thiol or thiolether compounds) that can chemically interact with ruthenium. This parameter change transforms the slurry from a purely mechanical abrasive system to a chemically-active system capable of effectively removing ruthenium while maintaining processability
2Reliability
If the hardness of ruthenium is increased for better barrier properties, then the adhesion and electrical properties improve, but the difficulty of processing in CMP increases
Solution Approach 1:
The chelating agent acts as a chemical intermediary that temporarily modifies the surface properties of hard ruthenium during the CMP process. By forming coordinate covalent bonds with ruthenium, it creates a softer, more removable surface layer without altering the bulk material properties, thus enabling processing of high-hardness ruthenium while preserving its reliable adhesion and electrical characteristics
Solution Approach 2:
The chemical environment parameters of the CMP slurry are modified to include chelating agents that can selectively interact with ruthenium's hard surface. This parameter change enables the processing of high-hardness materials by creating a chemically-active interface that reduces the effective hardness at the polishing interface while maintaining the bulk material's desirable properties
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 CMP slurry composition effectively polishes ruthenium, enabling its integration into semiconductor manufacturing processes by improving the removal rate and overcoming the challenges posed by ruthenium's chemical inertness and hardness.
Implementation Method 1
A CMP slurry composition is developed that includes a chelator, such as a thiol or thiolether compound, to enhance the removal rate of ruthenium by forming coordinate covalent bonds
Implementation Method 2
chemical mechanical polishing (CMP) processes
Data Source
AI summary
A CMP slurry composition and a method of polishing a metal layer are provided. In some embodiments, the CMP slurry composition includes about 0.1 to 10 parts by weight of a metal oxide, and about 0.1 to 10 parts by weight of a chelator. The chelator includes a thiol compound or a thiolether compound.