CMP Carrier Head Composite Plastic Corrosion Resistance
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Solution Overview
Problem
Chemical mechanical polishing (CMP) carrier heads with metal internal components, such as aluminum, are prone to corrosion from acidic slurries used in metal layer polishing, leading to defects and reduced lifetime.
Innovation Solution
The use of composite plastics with a tensile modulus comparable to or greater than aluminum for internal components, combined with stainless steel parts, forms a corrosion-resistant and rigid structure that maintains polishing uniformity and reduces noise in eddy current monitoring systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal internal components (aluminum) are used in carrier head, then rigidity is provided for the retaining ring, but corrosion occurs from acidic slurry leading to defects and reduced lifetime
Solution Approach 1:
The patent applies composite materials by combining plastic base material with glass fibers or metal particles to create a composite structure that provides both the required rigidity (comparable to or greater than aluminum) and corrosion resistance. The composite material maintains structural integrity while being substantially inert to acidic slurries, resolving the contradiction between strength and corrosion resistance.
Solution Approach 2:
The patent changes the material parameters by selecting plastic materials with specific tensile modulus values (comparable to or greater than aluminum) and combining them with reinforcing agents (glass fibers, metal particles) in specific concentrations. This parameter optimization allows the composite material to achieve both rigidity and corrosion resistance simultaneously.
2Reliability
If composite plastic is used for internal components, then corrosion resistance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes manufacturing parameters by specifying glass fiber content (30-70% by weight) and metal particle content (1-50% by weight) to achieve the desired balance between corrosion resistance and manufacturability. These parameter ranges are selected to ensure the composite material can be effectively processed while maintaining performance.
Solution Approach 2:
The use of composite materials with specific compositions (glass-filled plastic, plastic with metal particles) provides a standardized solution that balances corrosion resistance with manufacturing feasibility. The composite structure allows for consistent production while achieving the required material properties.
3Strength
If glass-filled plastic is used, then tensile modulus is increased to match aluminum, but manufacturing precision requirements increase
Solution Approach 1:
The patent carefully controls the glass fiber content parameter (30-70% by weight) to optimize the balance between tensile modulus and dimensional stability. This parameter control ensures that the composite material achieves aluminum-equivalent rigidity while maintaining manufacturability and dimensional precision.
Solution Approach 2:
The glass-filled plastic composite provides enhanced tensile modulus through the reinforcing effect of glass fibers, while the plastic matrix maintains dimensional stability and ease of molding. This composite structure resolves the contradiction between strength enhancement and manufacturing precision.
Data Source
AI summary
A chemical mechanical polishing head includes a base assembly that includes at least one component formed of a composite plastic having a tensile modulus approximately equal to or greater than aluminum, a retaining ring secured to the base assembly, and a flexible membrane secured to the base assembly to form a pressurizable chamber between the base assembly and an upper surface of the flexible membrane. A lower surface of the flexible membrane provides a substrate mounting surface.