Soft CMP Pad with Window for Defect Control
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Solution Overview
Problem
Conventional chemical mechanical polishing pads face challenges in maintaining low defectivity and effective conditionability due to high ductility, which hinders texture creation and groove quality, and endpoint detection windows lack durability for demanding semiconductor applications.
Innovation Solution
A chemical mechanical polishing pad with a polishing layer and integrated endpoint detection window, formulated with specific polyurethane prepolymers and curatives, providing a balance of low hardness, high elongation, and improved optical properties to facilitate low defect polishing and durable endpoint detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a softer polishing pad is used to reduce polishing defects, then defectivity is reduced, but conditionability deteriorates due to high ductility preventing texture creation
Solution Approach 1:
The patent modifies the physical and chemical parameters of the polishing pad material by incorporating specific polyurethane prepolymers and curatives to achieve optimal hardness and elongation properties. This allows the pad to be soft enough to reduce defects while maintaining sufficient rigidity for effective conditioning and texture creation.
Solution Approach 2:
The patent uses composite material formulation combining polyurethane prepolymers with specific curatives (amines, polyols, isocyanates) to create a polishing pad with balanced properties. The composite structure enables simultaneous achievement of low defectivity through softness and good conditionability through controlled elasticity and texture formation.
2Ease of manufacture
If conventional polishing pad materials are used, then ease of manufacture is maintained, but groove quality and texture creation are hindered due to high ductility
Solution Approach 1:
The patent adjusts the material parameters through controlled polymerization reactions, optimizing the molecular structure to reduce excessive ductility. This enables the material to hold grooves and textures effectively during conditioning while remaining manufacturable through standard processes.
3Device complexity
If conventional endpoint detection windows are used, then device complexity is reduced, but reliability deteriorates due to lack of durability for demanding semiconductor applications
Solution Approach 1:
The patent enhances the physical and chemical parameters of the endpoint detection window material to improve its durability. Through optimized polymer formulation and curing processes, the window achieves sufficient mechanical strength and chemical resistance to withstand demanding semiconductor polishing applications while maintaining optical transparency.
Data Source
AI summary
A chemical mechanical polishing pad is provided having a polishing layer; and a window incorporated into the polishing layer; wherein the polishing layer comprises a reaction product of ingredients, including: a polishing layer prepolymer and a polishing layer curative system; wherein the polishing layer curative system includes a polishing layer amine initiated polyol curative, a polishing layer high molecular weight polyol curative and a polishing layer difunctional curative; and, wherein the window comprises a reaction product of ingredients, including: a window prepolymer and a window curative system; wherein the window curative system includes a window difunctional curative, a window amine initiated polyol curative and a window high molecular weight polyol curative; and, wherein the polishing layer exhibits a density of ≧0.6 g/cm3; a Shore D hardness of 5 to 40; an elongation to break of 100 to 450%; and, a cut rate of 25 to 150 μm/hr.