UV Curable CMP Polishing Pad Manufacturing via Photopolymerization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Chemical mechanical polishing (CMP) processes face challenges in achieving uniformity and maintaining mechanical integrity, chemical resistivity, and hydrophilicity in polishing pads, which affect the polishing rate and surface quality of substrates.
Innovation Solution
The method involves introducing polymer precursors with acrylate functional groups and abrasive particles into a mold, exposing them to ultraviolet radiation to form a cross-linked polymer matrix with dispersed abrasive particles, and optionally incorporating porogens or thermal initiators to create porosity and enhance mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional molding or casting methods are used to manufacture polishing pads, then the pads can be produced with sufficient mechanical integrity and chemical resistivity, but the tunability of mechanical properties and polishing performance is limited
Solution Approach 1:
The patent applies parameter changes by systematically varying the composition ratios of polyol, isocyanate, and silane in the reaction mixture, along with adjusting catalyst amounts and curing conditions. These parameter modifications enable precise control over crosslinking density, pore structure, and mechanical properties of the polishing pad, achieving high tunability while maintaining manufacturing feasibility through a standardized RTM process
Solution Approach 2:
The patent employs composite materials by combining organic polymeric components (polyol, isocyanate) with inorganic silane particles and abrasive particles. This composite approach creates a hybrid material system where the silane provides structural framework and chemical stability, while the polymeric matrix provides flexibility and polishing performance, enabling simultaneous optimization of multiple properties
2Shape
If the polishing pad is made harder to improve planarity, then the planarity improves, but the pad wear increases and mechanical integrity decreases
Solution Approach 1:
The composite structure combining soft polymeric matrix with rigid silane framework and dispersed abrasive particles enables the pad to maintain planarity through the rigid framework while the flexible polymeric matrix absorbs stress and prevents excessive wear, resolving the contradiction between hardness and mechanical integrity
Solution Approach 2:
The patent implements local quality by creating regions of different crosslinking densities and particle concentrations within the pad structure. The silane framework provides localized rigid support for planarity, while areas with higher polymeric content provide flexibility and wear resistance, allowing different regions to fulfill different functional requirements
3Productivity
If the polishing pad is made more abrasive to improve polishing rate, then the polishing rate increases, but the pad wear increases and surface roughness increases
Solution Approach 1:
The patent applies local quality by strategically distributing abrasive particles within the pad structure and creating zones with varying abrasive concentration. This allows high polishing rate in contact regions while maintaining smoother surface characteristics in non-contact areas, and the controlled crosslinking ensures abrasive particles remain embedded to prevent excessive wear
Solution Approach 2:
The composite material system embeds abrasive particles within a crosslinked silane-polymer matrix, providing mechanical support that prevents particle detachment and excessive pad wear while maintaining high polishing rate. The matrix acts as a binder that holds abrasives firmly, reducing wear compared to traditional bonded abrasive pads
4Strength
If crosslinking density is increased to improve mechanical strength, then the mechanical strength improves, but the chemical resistivity decreases and hydrophilicity decreases
Solution Approach 1:
The patent applies parameter changes by controlling the crosslinking reaction conditions, including catalyst concentration, curing temperature, and silane-to-polyol ratio. These parameter adjustments optimize the crosslinking density to achieve adequate mechanical strength while preserving chemical resistivity by avoiding excessive crosslinking that would create internal stresses and reduce hydrophilicity
Solution Approach 2:
The patent employs porous materials by creating a controlled pore structure within the crosslinked network. These pores, formed by gas bubbles or voids during the curing process, reduce the effective crosslinking density, thereby maintaining chemical resistivity and hydrophilicity while the overall crosslinked framework provides sufficient mechanical strength
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
This approach results in CMP polishing pads with improved tunability, mechanical strength, abrasion resistance, and chemical stability, enabling uniform polishing and maintaining surface quality over multiple cycles.
Implementation Method 1
exposing the mixture to ultraviolet radiation through a transparent section of the mold to cause the polymer precursors to form radicals. The method includes forming a polymer matrix from the polymer precursor by causing the radicals to cross-link with one another
Data Source
AI summary
A method of fabricating a chemical mechanical polishing pad includes introducing polymer precursors containing acrylate functional groups into a mold, providing abrasive particles and a photo-initiator in the polymer precursors to form a mixture, and while the mixture is contained between a bottom plate and a top cover of the mold, exposing the mixture to ultraviolet radiation through a transparent section of the mold to cause the polymer precursors to form radicals, forming a polymer matrix from the polymer precursor by causing the radicals to cross-link with one another. The polishing layer includes the polymer matrix having the abrasive particles dispersed therein.