CMP Pad with Composite Matrix for Planarization
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Solution Overview
Problem
Current polishing pads, such as hard cast polyurethane pads, while providing mechanical integrity and chemical resistance, tend to increase defects during semiconductor fabrication, particularly in silicon oxide/silicon nitride applications, and fail to meet stringent planarization and defectivity requirements due to limited performance variability with substrates and polishing conditions.
Innovation Solution
A chemical mechanical polishing pad with a high modulus polymeric matrix and an impact modifier, where the low modulus component is distributed within the matrix to enhance impact resistance, achieving improved planarization and defectivity performance by combining materials with moduli of at least 100 MPa to 5,000 MPa, and volume percentages of 1 to 50%, respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hard cast polyurethane polishing pads are used, then planarization ability is improved, but defectivity increases
Solution Approach 1:
The polishing pad uses a composite structure combining hard cast polyurethane matrix with dispersed soft polymeric microspheres (1-50 volume percent). This composite material provides both the planarization ability of the hard matrix and the defect-reducing properties of the soft inclusions, resolving the contradiction between planarization performance and defectivity.
Solution Approach 2:
The polishing pad features non-uniform local properties: the hard polyurethane matrix provides planarization in high-stress areas, while the soft microspheres distributed throughout (1-50 vol%) provide defect reduction and cushioning. This local differentiation of material properties allows simultaneous achievement of planarization and low defectivity.
2Strength
If hard cast polyurethane polishing pads are used, then mechanical integrity is improved, but impact resistance deteriorates
Solution Approach 1:
The polishing pad combines hard cast polyurethane (providing mechanical integrity and tensile strength) with soft polymeric microspheres (providing impact resistance). The soft microspheres act as energy-absorbing inclusions that mitigate impact forces while the continuous hard matrix maintains structural integrity, resolving the contradiction between strength and impact resistance.
Solution Approach 2:
The soft polymeric microspheres are pre-distributed throughout the hard polyurethane matrix (1-50 volume percent) to provide beforehand cushioning against impact forces. This pre-positioned soft phase absorbs impact energy before it can propagate through the hard matrix, protecting the pad from impact damage while maintaining mechanical integrity.
3Manufacturing precision
If polishing pad hardness is increased, then planarization performance is improved, but adaptability to different substrates deteriorates
Solution Approach 1:
The polishing pad uses a composite system where the hard polyurethane matrix (providing planarization performance) is combined with soft polymeric microspheres (providing adaptability). The soft inclusions allow the pad to conform to different substrate geometries and polishing conditions, while the hard matrix maintains planarization capability, resolving the contradiction between performance and adaptability.
Solution Approach 2:
The polishing pad achieves variable effective hardness through parameter changes: the hard matrix maintains high modulus for planarization, while the dispersed soft microspheres (1-50 vol%) can deform and adapt to different substrate conditions. This dual-phase structure allows the pad to maintain consistent planarization performance across different substrates by dynamically adjusting its effective compliance.
Data Source
AI summary
A chemical mechanical polishing pad is suitable for polishing at least one of semiconductor, optical and magnetic substrates. The polishing pad has a high modulus component forming a continuous polymeric matrix and an impact modifier within the continuous polymeric matrix. The high modulus component has a modulus of at least 100 MPa. The impact modifier includes a low modulus component having a modulus of at least one order of magnitude less than the high modulus component that increases the impact resistance of the polishing pad.