CMP Pad Window Adhesive Sealant Gap Filling
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Solution Overview
Problem
Existing polishing pads with windows face challenges in maintaining window integrity during chemical mechanical polishing (CMP) processes, including delamination, leakage, and warping, which affect the accuracy of endpoint detection and polishing uniformity.
Innovation Solution
A polishing pad design featuring a polishing layer stack with a recessed light-transmitting body and an adhesive sealant that laterally fills the gap between the light-transmitting body and the aperture walls, secured by a fluid-impermeable layer and adhesive layers, reduces the risk of delamination and leakage while allowing for a larger window size without increasing delamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a window is provided in the polishing pad to enable optical monitoring, then endpoint detection capability is improved, but the risk of delamination and leakage increases
Solution Approach 1:
The window structure is divided into multiple functional segments: a light-transmitting body for optical monitoring, an adhesive sealant for sealing, and a fluid-impermeable layer for fluid barrier. This segmentation allows each component to perform its specific function optimally while collectively solving the delamination and leakage problem.
Solution Approach 2:
An adhesive sealant is introduced as an intermediary element between the light-transmitting body and the polishing pad substrate. This sealant fills the gap and provides both mechanical attachment and fluid sealing, eliminating the delamination and leakage issues without compromising the optical function.
2Productivity
If the polishing pad is made thin to reduce conditioning time, then productivity is improved, but the structural integrity and resistance to delamination deteriorate
Solution Approach 1:
The polishing pad employs a composite structure combining a thin polishing layer with a fluid-impermeable layer and adhesive sealant. This composite design maintains overall thinness for rapid conditioning while the additional layers provide structural integrity and delamination resistance.
Solution Approach 2:
The adhesive sealant is applied in advance to secure the light-transmitting body to the polishing pad substrate before the polishing process begins. This preliminary action ensures structural integrity is established prior to use, preventing delamination during operation despite the thin overall structure.
3Measurement precision
If the light-transmitting body is made larger to improve monitoring coverage, then measurement precision is improved, but the risk of scratching and delamination increases
Solution Approach 1:
The adhesive sealant serves as a protective intermediary between the light-transmitting body and the external environment. It fills the gap around the light-transmitting body, preventing direct contact between abrasive particles and the window edges, thereby reducing scratching risk even when the window is made larger.
Solution Approach 2:
The fluid-impermeable layer and adhesive sealant are positioned beforehand to create a protective barrier around the light-transmitting body. This prior cushioning protects the window from mechanical damage and delamination during the polishing process, enabling larger window sizes without increased scratching risk.
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 design enhances the reliability of endpoint detection by maintaining window transparency and reducing the risk of scratching, while ensuring the polishing pad remains secure and effective during CMP processes, improving polishing uniformity and endpoint detection accuracy.
Implementation Method 1
An adhesive sealant of a different second material is disposed in and laterally fills the gap
Implementation Method 2
The light-transmitting body is positioned in the aperture and has a lower surface in contact with, is secured to the first adhesive layer
Data Source
AI summary
A polishing pad includes a polishing layer stack that has a polishing surface, a bottom surface, and an aperture from the polishing surface to the bottom surface. The polishing layer stack includes a polishing layer that has the polishing surface. A fluid-impermeable layer spans the aperture and the polishing pad. A first adhesive layer of a first adhesive material is in contact with and secures the bottom surface of the polishing layer to the fluid-impermeable layer. The first adhesive layer spans the aperture and the polishing pad. The light-transmitting body is positioned in the aperture and has a lower surface in contact with, is secured to the first adhesive layer, and is spaced apart from a side-wall of the aperture by a gap. An adhesive sealant of a different second material is disposed in and laterally fills the gap.