Thiol-Ene Polishing Pad for Additive Manufacturing
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Solution Overview
Problem
Existing chemical mechanical polishing pads produced by additive manufacturing lack sufficient toughness, elongation, and wear resistance, which are essential for effective polishing of semiconductor wafers.
Innovation Solution
A chemical mechanical polishing pad comprising a photocured polymer formed from a photocurable material that includes molecules with two or more functional groups, such as thiol and ethylenically unsaturated groups, which react to form a thioether link, without using (meth)acrylate groups, allowing for improved mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If droplet jet 3D printing with photocurable materials is used to manufacture polishing pads, then additive manufacturing capability is achieved, but toughness and elongation properties are limited resulting in high wear rates
Solution Approach 1:
The patent changes the chemical parameters of the photocurable material by using thiol-ene chemistry instead of traditional acrylate/methacrylate systems. This parameter change in the chemical composition enables both additive manufacturability and improved mechanical properties including toughness, elongation, and wear resistance.
Solution Approach 2:
The patent employs composite material strategy by combining thiol-containing compounds with ene-containing compounds to create a photocurable composition. This composite approach leverages the complementary properties of both components, where thiol groups provide crosslinking density and ene groups enable photocuring, resulting in material with superior mechanical properties while maintaining 3D printability.
2Ease of manufacture
If traditional photocurable materials with (meth)acrylate groups are used, then chain-growth photocuring is achieved, but toughness and elongation are limited
Solution Approach 1:
The patent inverts the traditional photocuring approach by using thiol-ene click chemistry instead of conventional free radical polymerization of acrylates. This inversion of the chemical mechanism leads to step-growth polymerization with superior network formation, resulting in enhanced toughness and elongation while maintaining photocuring capability.
Solution Approach 2:
The patent changes the fundamental chemical parameters of the photocuring system by replacing (meth)acrylate groups with thiol and ene functional groups. This parameter change transforms the curing mechanism from chain-growth to step-growth polymerization, producing a polymer network with better mechanical 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 proposed polishing pad exhibits enhanced toughness, elongation, and wear resistance, comparable to or exceeding those of conventional polishing pads, thereby improving the effectiveness of chemical mechanical polishing processes.
Implementation Method 1
the photocure includes reaction of the thiol group with the ethylenically unsaturated group
Data Source
AI summary
A chemical mechanical polishing pad comprising a polishing layer that comprises a photocured polymer wherein the photocured polymer is the photoinitiated reaction product of a photocurable material that is free of molecules comprising (meth)acrylate groups and the photocurable material comprises molecules having two or more functional groups wherein the functional groups include a thiol group and ethylenically unsaturated group other than a (meth)acrylate group and the photocure includes reaction of the thiol group with the ethylenically unsaturated group, provided at least some of the molecules comprise three or more functional groups. The chemical mechanical polishing pad can be made by additive manufacturing using stereolithography.