UV-Cured Sub-Pad Composition for Adhesive-Free CMP Polishing Pads
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Solution Overview
Problem
Conventional polishing pads for chemical-mechanical planarization in semiconductor fabrication require multiple steps and adhesives, leading to inconsistencies and inefficiencies in pressure distribution and mechanical properties.
Innovation Solution
A UV-cured sub-pad composed of a (meth)acrylate monomer unit and an oligomer unit, such as difunctional (meth)acrylate-capped polyether urethane oligomer, is used to form a polishing pad without adhesives, ensuring uniform pressure distribution and improved polishing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal set materials are laminated to the top sheet using adhesive, then the sub-pad provides support for the top sheet, but the process requires multiple steps and introduces additional chemicals leading to pad inconsistencies
Solution Approach 1:
The patent combines the sub-pad material itself to serve dual functions: providing mechanical support and acting as the adhesive bonding layer. The composition includes polymerizable monomers/oligomers that form a cohesive network structure, eliminating the need for separate structural and adhesive components. This merging reduces manufacturing steps from multiple lamination operations to a single coating and curing process.
Solution Approach 2:
The invention extracts and eliminates the separate adhesive layer from the traditional two-layer structure (adhesive + sub-pad). By incorporating adhesive functionality directly into the sub-pad composition through polymerizable components, the patent removes the need for additional adhesive chemicals and simplifies the material system while maintaining bonding performance.
2Strength
If thermal set materials are used for the sub-pad, then the sub-pad provides structural support, but the lamination process introduces solvents and potential adhesion unevenness
Solution Approach 1:
The patent changes the chemical state and bonding mechanism from thermal set adhesive bonding to UV-initiated polymerization. The composition contains polymerizable monomers and oligomers that form strong covalent bonds through photopolymerization, providing superior adhesion uniformity. The UV curing process enables precise control of the bonding reaction, eliminating the variability associated with thermal lamination and solvent evaporation.
Solution Approach 2:
The sub-pad composition is designed as a composite system containing polymerizable monomers, oligomers, and optional fillers or modifiers. This composite formulation provides both structural integrity and adhesive bonding capability within a single material system, achieving uniform adhesion across the entire bonding interface while maintaining the required mechanical strength and support properties.
3Ease of manufacture
If multiple lamination steps are used to attach the sub-pad, then the polishing pad is formed, but the process introduces additional chemicals and increases manufacturing complexity
Solution Approach 1:
The sub-pad composition is self-bonding through its inherent polymerizable components. When exposed to UV light, the monomers and oligomers spontaneously polymerize and form strong bonds with the top sheet without requiring external adhesives or solvents. This self-service mechanism eliminates the need for additional chemical agents and simplifies the manufacturing process to a single coating and curing step.
Solution Approach 2:
The patent replaces the mechanical/thermal lamination process with a photochemical bonding mechanism. Instead of using heat and pressure to activate adhesive bonding, the invention uses UV light to initiate polymerization and create covalent bonds. This substitution eliminates the need for thermal equipment, pressure systems, and solvent-based adhesives, reducing both manufacturing complexity and chemical waste.
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 UV-cured sub-pad provides improved polishing uniformity and consistency, reducing waste and costs while enhancing the efficiency and durability of the polishing process.
Implementation Method 1
UV curing the UV-curable composition to provide the polishing pad
Data Source
AI summary
The disclosure provides a UV-cured sub-pad for chemical-mechanical planarization comprising (a) a (meth)acrylate monomer unit and (b) an oligomer unit selected from a difunctional (meth)acrylate-capped polyether urethane oligomer unit, a difunctional (meth)acrylate-capped polyester urethane oligomer unit, a difunctional (meth)acrylate-capped urethane oligomer unit, and a combination thereof. The disclosure also provides a polishing pad for chemical-mechanical planarization comprising a top sheet and a UV-cured sub-pad, a method of preparing the polishing pad, and an apparatus for performing the method of preparing the polishing pad for chemical-mechanical planarization.