CMP Polishing Pad Pore Structure Control
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Solution Overview
Problem
The existing methods for creating polishing pads for semiconductor CMP processes face challenges in precisely controlling the size, shape, and coalescence of micropores, which affects the polishing rate and surface quality, leading to defects like scratches and chatter marks.
Innovation Solution
A polishing pad with pores having an average diameter of 5 μm to 200 μm and a sphericity of 0.2 to 0.9, achieved by mixing a urethane-based prepolymer, a solid phase foaming agent, and a curing agent, and molding the mixture to control the pore structure and volume ratio, thereby minimizing coalescence and enhancing polishing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a gas phase or volatile liquid phase foaming agent is used to form micropores, then no material affecting the CMP process is discharged, but it is difficult to precisely control the size, size distribution, and amount of pores
Solution Approach 1:
The patent changes the physical state parameter of the foaming agent from gas/volatile liquid phase to solid phase, enabling precise control of pore characteristics while maintaining environmental benefits. The solid phase foaming agent allows control of pore size, shape, and distribution through particle size selection and surface treatment.
Solution Approach 2:
The patent uses composite solid phase foaming agents with specific surface treatments (hydrophobic or hydrophilic coatings) combined with polymer matrices, creating a composite structure that prevents coalescence and maintains pore shape stability during CMP processing.
2Manufacturing precision
If a solid phase foaming agent is used to precisely control pore shape and distribution, then pore shape can be maintained during CMP process, but the solid phase foaming agents may coalesce with each other
Solution Approach 1:
The patent introduces surface treatment agents (hydrophobic or hydrophilic coatings) as intermediaries on the solid phase foaming agent surface, creating a protective barrier that prevents direct contact and coalescence between foaming agents during mixing and processing.
Solution Approach 2:
The patent changes the surface energy parameters of the solid phase foaming agent through surface treatment, creating repulsive forces between particles that prevent coalescence while maintaining the desired pore structure formation capability.
3Manufacturing precision
If small sized solid phase foaming agents (millimeter or less) are used, then pore size can be controlled, but the density is extremely low causing adjacent foaming agents to coalesce
Solution Approach 1:
The patent creates composite solid phase foaming agents with enhanced density through surface treatment and material composition optimization, allowing small particle sizes for precise pore control while preventing coalescence through improved interparticle interactions.
Solution Approach 2:
The patent changes the density parameter of solid phase foaming agents through surface treatment and material selection, enabling small particle sizes for precise pore control while maintaining sufficient density to prevent coalescence during processing.
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 controlled pore structure improves polishing speed and reduces surface defects such as scratches and chatter marks, resulting in better semiconductor substrate planarization and polishing characteristics.
Implementation Method 1
or by generating a gas by a chemical reaction
Implementation Method 2
a liquid phase foaming agent filled with a volatile liquid
Data Source
AI summary
Embodiments relate to a polishing pad for use in a chemical mechanical planarization (CMP) process of semiconductors, a process for preparing the same, and a process for preparing a semiconductor device using the same. According to the embodiments, it is possible to provide a polishing pad in which the average diameter of the plurality of pores contained in the polishing pad, the sphericity of the plurality of pores, and the volume ratio thereof are adjusted, thereby enhancing the polishing speed and reducing surface such defects as scratches and chatter marks appearing on the surface of a semiconductor substrate.