UV-Curable Resin CMP Pad via Vat Photopolymerization
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Solution Overview
Problem
Conventional chemical-mechanical polishing (CMP) pads lack desirable properties for uniform polishing, such as being too brittle and having inconsistent material removal rates, which can lead to over- or under-polishing, and their manufacturing processes are costly and labor-intensive.
Innovation Solution
A CMP pad made from a UV-curable resin using a vat-based additive manufacturing process, which omits the chain extender and thermal curing step, allowing for a CMP pad with improved mechanical and chemical properties, increased planarization efficiency, and reduced manufacturing costs, by forming a continuous single-layer body with precisely controlled structures and properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional molding or casting processes are used to prepare CMP pads, then the pads can be manufactured with existing processes, but the pads become too brittle and lack desirable properties for effective CMP
Solution Approach 1:
The patent changes the chemical parameters of the resin formulation by eliminating chain extenders and using a simplified UV-curable composition with acrylate monomers, oligomers, and photoinitiators. This parameter change transforms the material properties to achieve desirable mechanical characteristics while maintaining ease of manufacture through UV curing.
Solution Approach 2:
The patent utilizes the phase transition of the resin from liquid precursor to solid cured material through UV-induced photopolymerization. This phase transition enables the formation of a continuous single-layer body with controlled mechanical properties without requiring thermal curing or chain extenders.
2Reliability
If dual curing processes (UV and thermal) with chain extenders are used, then the resin can be fully cured, but the process becomes more complex and time-consuming
Solution Approach 1:
The patent extracts and eliminates the chain extender component from the traditional dual-curing resin system. By removing the amine-based chain extender, the patent simplifies the curing process to UV-only while maintaining complete curing through optimized photoinitiator selection and UV irradiation parameters.
Solution Approach 2:
The patent merges the functions of chain extension and crosslinking into a single UV-curing step. The acrylate-functional oligomers and monomers directly crosslink upon UV exposure, combining what were traditionally separate thermal chain extension and UV crosslinking steps into one unified process.
3Manufacturing precision
If additive manufacturing is used to form CMP pads, then continuous single-layer bodies with precise structural control can be created, but the manufacturing process must be optimized for UV curing
Solution Approach 1:
The patent performs preliminary action by formulating the resin with specific acrylate monomers and oligomers that are pre-configured for optimal UV curing in additive manufacturing. The resin composition is designed beforehand to ensure proper viscosity, cure depth, and mechanical properties when processed layer-by-layer through UV irradiation.
4Ease of manufacture
If conventional extrusion-based processes are used, then CMP pads can be manufactured, but the pads are too brittle and require multiple layers with adhesives
Solution Approach 1:
The patent replaces the mechanical extrusion-based manufacturing system with a UV-curing additive manufacturing system. This substitution eliminates the need for mechanical layer deposition and adhesive bonding, instead using photopolymerization to create a continuous, monolithic structure with superior integrity and flexibility.
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 pad achieves high removal rates and increased planarization efficiency while reducing manufacturing costs and resources, providing a more uniform polishing process compared to conventional pads.
Implementation Method 1
UV curing, i.e., a low-temperature, high-speed process by which ultraviolet light is used to initiate a photochemical reaction that generates a crosslinked network of polymers
Data Source
AI summary
The invention provides a UV-curable resin for forming a chemical-mechanical polishing pad comprising: (a) one or more acrylate blocked isocyanates; (b) one or more acrylate monomers; and (c) a photoinitiator. The invention also provides a method of forming a chemical-mechanical polishing pad using the UV-curable resin.