Photocured Polishing Pad Toughness via Thiol-Acrylate Crosslinking
Solution Overview
Problem
Existing chemical mechanical polishing pads produced by additive manufacturing have limited toughness, elongation, and wear resistance, making them less suitable for effective polishing in semiconductor wafer processing.
Innovation Solution
A chemical mechanical polishing pad is developed using a photocured polymer formed from a reaction mixture containing molecules with two or more functional groups, including thiol and ethylenically unsaturated groups, such as (meth)acrylate groups, where the photocure involves the reaction of thiol groups with (meth)acrylate groups, resulting in a polymer with improved mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If photocurable materials with acrylate or methacrylate groups are used for additive manufacturing of polishing pads, then the pads can be produced with complex three-dimensional patterns and porosity, but the resulting polymers have poor toughness and elongation properties leading to high wear rates
Solution Approach 1:
The patent combines multiple photocurable functional groups (acrylate, methacrylate, and additional reactive groups) within the same polymer system to create a composite material structure. This allows the material to exhibit both the manufacturability of photocurable systems and the enhanced mechanical properties of crosslinked networks, resolving the contradiction between ease of manufacture and strength.
Solution Approach 2:
The patent changes the chemical composition parameters of the photocurable material by incorporating specific ratios of different functional groups and crosslinking agents. By adjusting these parameters, the material achieves optimal balance between photocuring efficiency (for additive manufacturing) and mechanical properties (toughness and elongation), thereby resolving the technical contradiction.
2Manufacturing precision
If conventional photocuring systems are used in additive manufacturing, then the material can be selectively cured to form three-dimensional structures, but the cured polymers exhibit limited toughness and elongation resulting in undesirably high wear rates
Solution Approach 1:
The patent creates a composite photocuring system that integrates multiple reactive functional groups and crosslinking mechanisms. This composite approach maintains the selective curing precision needed for additive manufacturing while simultaneously improving wear resistance through enhanced crosslinked network structure, thus resolving the contradiction between manufacturing precision and reliability.
Solution Approach 2:
The patent modifies the chemical parameters of the photocurable composition by incorporating specific crosslinking agents and adjusting the ratio of reactive groups. These parameter changes enable the material to achieve both high curing precision (for accurate 3D structure formation) and improved wear resistance (for reliable polishing pad performance), resolving the technical contradiction.
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 photocured polymer is the photoinitiated reaction product of a photocurable material comprising molecules having two or more functional groups wherein the functional groups include a thiol group and an ethylenically unsaturated group
Data Source
AI summary
A chemical mechanical polishing pad comprising a photocured polymer wherein the photocured polymer is the photoinitiated reaction product of a photocurable material comprising molecules having two or more functional groups wherein the functional groups include a thiol group and an ethylenically unsaturated group, provided for at least a portion of the molecules having the ethylenically unsaturated group, the ethylenically unsaturated group is a (meth)acrylate group, wherein the (meth)acrylate groups comprise less than 70 mole percent of total (meth)acrylate, thiol, and ethylenically unsaturated functional groups and wherein 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.