Multilayer Polishing Pad Stack with Soft Conditionable Layer
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Solution Overview
Problem
Conventional chemical mechanical polishing pad materials exhibit high ductility, making it difficult to create favorable microtexture during conditioning and forming macro groove patterns, leading to poor conditionability and machining issues.
Innovation Solution
A multilayer chemical mechanical polishing pad stack with a polishing layer having a density greater than 0.6 g/cm3, Shore D hardness of 5 to 40, and elongation to break of 100 to 450%, bonded to a rigid layer via hot melt adhesive, facilitating enhanced conditionability and machinability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polishing pad materials are used, then the pad provides basic polishing function, but the high ductility makes it difficult to create favorable microtexture during conditioning and forming macro groove patterns
Solution Approach 1:
The patent changes the physical parameters of the polishing layer by controlling density (0.6-1.2 g/cm³), Shore D hardness (5-40), and elongation to break (100-450%). These parameter modifications enable the material to be soft enough for good polishing performance yet rigid enough to be properly conditioned with diamond disks, resolving the contradiction between microtexture creation and ease of conditioning.
Solution Approach 2:
The patent employs composite material construction with a polishing layer bonded to a support layer via hot melt adhesive. The polishing layer uses specialized polyurethane formulations with controlled porosity and crosslinking, while the support layer provides structural stability. This composite structure allows the polishing layer to achieve optimal conditionability and microtexture formation without compromising overall pad integrity.
2Reliability
If softer polishing pad materials are used, then polishing defects such as micro-scratches or chatter marks are reduced, but the material becomes difficult to machine and condition
Solution Approach 1:
The patent optimizes the hardness parameter to Shore D 5-40, which is soft enough to minimize polishing defects like micro-scratches and chatter marks, yet rigid enough to allow proper machining and conditioning. The controlled density (0.6-1.2 g/cm³) and elongation to break (100-450%) further refine the material properties to achieve this balance between softness for defect reduction and rigidity for manufacturability.
Solution Approach 2:
The patent divides the pad into two functional segments: a soft polishing layer (Shore D 5-40) that provides defect-free polishing and a support layer that provides structural integrity and machinability. The hot melt adhesive bonds these segments together, allowing each layer to perform its specific function optimally without compromising the other.
3Productivity
If the polishing layer is made softer to reduce polishing defects, then the cut rate and planarity improve, but the pad becomes difficult to condition and form groove patterns
Solution Approach 1:
The patent achieves optimal cut rate (25-150 μm/hr) and planarity through controlled material parameters including density (0.6-1.2 g/cm³), Shore D hardness (5-40), and elongation to break (100-450%). These parameters ensure the material is soft enough for high cut rate and excellent planarity, yet rigid enough to be properly conditioned with diamond disks to form groove patterns and maintain microtexture.
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 multilayer pad stack achieves improved polishing performance with reduced defect rates, enabling effective microtexture creation and groove formation, thereby enhancing the planarity and integrity of semiconductor wafers.
Implementation Method 1
a hot melt adhesive bonding the polishing layer to the rigid layer
Data Source
AI summary
A multilayer chemical mechanical polishing pad stack is provided containing: a polishing layer; a rigid layer; and, a hot melt adhesive bonding the polishing layer to the rigid layer; wherein the polishing layer exhibits a density of greater than 0.6 g/cm3; a Shore D hardness of 5 to 40; an elongation to break of 100 to 450%; and, a cut rate of 25 to 150 μm/hr; and, wherein the polishing layer has a polishing surface adapted for polishing the substrate.