Chemical Mechanical Polishing Pad Hydrolytic Instability
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Solution Overview
Problem
Conventional chemical mechanical polishing methods face challenges in achieving a balance between surface planarization and minimizing defect formation, particularly scratch defects, in semiconductor wafer processing, due to the trade-off between harder polishing layer materials that provide better planarization but higher defect counts.
Innovation Solution
A chemical mechanical polishing pad with a polishing layer that exhibits initial hydrolytic stability and sustained hydrolytic instability, composed of a cast polyurethane reaction product of a polyisocyanate and polyether based polyol with specific curative agents and microelements, bonded to a rigid layer via hot melt adhesive, and featuring a pressure sensitive platen adhesive layer, which creates dynamic contact with the substrate to polish surfaces effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If harder polishing layer materials are used, then planarization performance is improved, but defect formation (scratch defects) increases
Solution Approach 1:
The patent changes the chemical composition parameters of the polishing layer by using a polyurethane-based polymer with specific molecular weight and crosslink density. This creates a material that achieves the desired hardness for planarization while controlling the surface energy to reduce scratch defect formation during the polishing process.
Solution Approach 2:
The patent employs a composite polishing layer structure combining polyurethane polymer with specific fillers and additives. This composite formulation allows the material to exhibit both the mechanical hardness needed for effective planarization and the surface properties that minimize defect generation, resolving the trade-off between these two requirements.
2Stability of the object's composition
If polishing layer materials are made hydrolytically stable, then dimensional stability is improved, but polishing effectiveness decreases
Solution Approach 1:
The patent optimizes the hydrolytic stability parameters of the polyurethane polymer by selecting specific polyols and isocyanates with controlled reaction rates. This creates a polishing layer that maintains dimensional stability during storage and handling while allowing sufficient chemical reactivity with the substrate during the polishing process to achieve effective material removal.
Solution Approach 2:
The patent introduces a dynamic balance in the polishing layer composition where the material exhibits initial hydrolytic stability for dimensional control, but develops sustained hydrolytic instability during the polishing process. This allows the material to transition from a stable state during handling to an active state during polishing, maintaining both dimensional stability and polishing effectiveness.
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
This approach enables improved planarization performance while minimizing defects, such as scratch defects, on semiconductor wafers with exposed copper features, by maintaining dimensional stability and adaptability during extended water exposure.
Implementation Method 1
a hot melt adhesive interposed between the base surface of the polishing layer and the top surface of the rigid layer; wherein the hot melt adhesive bonds the polishing layer to the rigid layer
Implementation Method 2
creating dynamic contact between the polishing surface and substrate to polish a surface of the substrate
Data Source
AI summary
A method of chemical mechanical polishing a substrate is provided, including: providing a substrate; providing a chemical mechanical polishing pad, comprising: a polishing layer having a composition and a polishing surface, wherein the composition of polishing layer is selected to exhibit an initial hydrolytic stability; coupled with a sustained hydrolytic instability; a rigid layer having a top surface and a bottom surface; a hot melt adhesive interposed between the base surface of the polishing layer and the top surface of the rigid layer; wherein the hot melt adhesive bonds the polishing layer to the rigid layer; a pressure sensitive platen adhesive layer having a stack side and a platen side; wherein the stack side of the pressure sensitive platen adhesive layer is adjacent to the bottom surface of the rigid layer; and, creating dynamic contact between the polishing surface and substrate to polish a surface of the substrate.