Polishing Pad EPD Window via Additive Manufacturing
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Solution Overview
Problem
Existing polishing pads for chemical mechanical polishing (CMP) processes lack customization in material properties for endpoint detection (EPD) windows, which affects the accuracy and effectiveness of determining the completion of polishing tasks in electronic device fabrication.
Innovation Solution
The development of polishing pads with endpoint detection windows formed using additive manufacturing techniques, allowing for the creation of discrete regions with unique properties through the use of precursor compositions that form chemical bonds, enabling tailored material properties for improved wear rates and optical transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If commercially available polyurethane sheets or molding materials are used for EPD windows, then the polishing pad can be manufactured using standard materials, but the material properties cannot be optimized for specific CMP processes or polishing pad materials
Solution Approach 1:
The patent applies local quality by creating a window region with distinct material properties from the surrounding polishing pad material. The window is formed from a separate precursor composition that cures to provide optimized optical transparency and wear resistance specifically for the EPD function, while the rest of the pad maintains its polishing characteristics. This allows customization of material properties in the window region without compromising the overall pad performance.
Solution Approach 2:
The patent uses composite materials by combining the window precursor composition with the polishing pad precursor composition in a single additive manufacturing process. The window region and pad region are formed as a integrated composite structure with chemically bonded interfaces, allowing different material properties in different regions while maintaining structural integrity. This resolves the contradiction by enabling material optimization through composite construction rather than using uniform commercial materials.
2Reliability
If adhesive is used to adhere the window to the polishing pad material, then the window can be attached to the pad, but the interface may compromise optical transparency and wear resistance
Solution Approach 1:
The patent merges the window and polishing pad into a single integrated structure formed by additive manufacturing. The window precursor composition and pad precursor composition are deposited in sequence and chemically bonded during the curing process, eliminating the need for separate adhesive layers. This direct chemical bonding maintains optical transparency by removing adhesive interfaces that would scatter light, while simultaneously providing strong mechanical attachment for reliability.
Solution Approach 2:
The patent uses the cured precursor composition itself as an intermediary bonding layer between the window and pad regions. Rather than using a separate adhesive material, the cured polymer matrix formed from the precursor compositions creates a chemically bonded interface that serves as both the structural connector and the optically transparent medium, resolving the contradiction between attachment strength and optical clarity.
3Measurement precision
If the window material is not optimized for specific CMP processes, then standard materials can be used, but the endpoint detection accuracy and polishing completion determination are affected
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition, optical properties, and curing characteristics of the window material through customized precursor formulations. The window precursor composition can be tailored with specific monomers, oligomers, photoinitiators, and additives to optimize refractive index, light transmission, wear resistance, and curing speed for specific CMP applications. This material parameter customization enables enhanced endpoint detection accuracy without requiring complex device modifications.
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 customized polishing pads with endpoint detection windows provide enhanced accuracy and reliability in determining polishing completion, reducing undesired process events and maintaining consistent performance throughout the polishing process.
Implementation Method 1
dispensing a first precursor composition and a window precursor composition... forming a first layer... partially curing the dispensed first precursor composition and the dispensed window precursor composition
Implementation Method 2
partially curing the dispensed first precursor composition and the dispensed window precursor composition to form an at least partially cured first layer
Data Source
AI summary
Embodiments of the present disclosure provide for polishing pads that include at least one endpoint detection (EPD) window disposed through the polishing pad material, and methods of forming thereof. In one embodiment a method of forming a polishing pad includes forming a first layer of the polishing pad by dispensing a first precursor composition and a window precursor composition, the first layer comprising at least portions of each of a first polishing pad element and a window feature, and partially curing the dispensed first precursor composition and the dispensed window precursor composition disposed within the first layer.