Porous Polyurethane Polishing Pad Pore Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing porous polyurethane polishing pads for CMP processes face challenges in precisely controlling pore size and distribution, limiting the flexibility in designing pores and affecting polishing performance.
Innovation Solution
A porous polyurethane polishing pad is developed with a specific composition and process, using a urethane-based prepolymer, a curing agent, and thermally expanded microcapsules as a solid phase foaming agent, allowing for controlled pore diameter and distribution, resulting in a pad with uniform large and small pores for improved polishing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid phase foaming agent or inert gas is used to form pores, then the pores can be formed without discharging materials affecting the CMP process, but it is difficult to precisely control the diameter of pores and the density of the pad
Solution Approach 1:
The patent changes the physical state parameter of the foaming agent from liquid/gas phase to solid phase (microcapsules). This parameter change enables precise control of pore diameter through the predetermined size of microcapsules (5-50 μm), while maintaining the advantage of not discharging harmful materials during the CMP process.
Solution Approach 2:
The patent replaces the chemical/physical foaming mechanism (liquid phase or gas phase) with a mechanical foam structure (solid phase microcapsules). The microcapsules with predetermined sizes provide mechanical control over pore dimensions, enabling precise pore diameter control without relying on chemical reactions or gas expansion.
2Manufacturing precision
If thermally expanded microcapsules are used as a solid phase foaming agent, then the diameter of pores can be uniformly controlled, but the shape of the microcapsules changes under the reaction condition of high temperature
Solution Approach 1:
The patent introduces a shell structure as an intermediary protective layer around the microcapsule core. This shell maintains the shape and structural integrity of the microcapsules during high-temperature curing reactions, preventing deformation while allowing the internal foaming agent to expand and form uniform pores.
Solution Approach 2:
The patent uses composite microcapsule structures consisting of a shell material and a core foaming agent. The shell material provides thermal stability and shape maintenance during curing, while the core material provides the foaming function. This composite structure resolves the contradiction between shape stability and pore formation capability.
3Manufacturing precision
If micropores are implemented using a single method, then pores can be formed in conformation with the size and distribution as designed, but the degree of freedom in designing the pores is low
Solution Approach 1:
The patent segments the pore structure into multiple size categories by using mixed microcapsules of different sizes (5-50 μm range). This segmentation enables independent control of pore size distribution while maintaining precise manufacturing control. Different size ratios can be adjusted to achieve various polishing performance requirements.
Solution Approach 2:
The patent applies local quality by creating regions with different pore size distributions within the polishing pad. By controlling the ratio and distribution of different sized microcapsules, the patent achieves locally optimized polishing characteristics while maintaining overall uniformity, thereby increasing design freedom.
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 pad achieves controlled polishing performance by uniformly distributing pores, preventing scratches and optimizing the polishing rate, with specific properties such as average pore diameter, specific gravity, and breakdown voltage.
Implementation Method 1
microcapsules (i.e., thermally expanded microcapsules), whose size has been adjusted by a thermal expansion
Data Source
AI summary
An embodiment relates to a porous polyurethane polishing pad for use in a chemical mechanical planarization (CMP) process of semiconductors and a process for preparing the same. In the porous polyurethane polishing pad, the polishing performance (or polishing rate) thereof can be controlled by adjusting the size and distribution of pores in the polishing pad.