Silane-Modified CMP Polishing Pad for Low-Defect Wafer Planarity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional polishing pads used in chemical mechanical planarization (CMP) processes suffer from high defect rates, such as scratches and chatter marks, which adversely affect the yield and quality of semiconductor wafers.
Innovation Solution
A polishing pad comprising a polyurethane with a silane repeating unit in its main chain, designed to have specific contact angle differences with pure water and fumed silica slurry, and a foamed body structure, is used in conjunction with a fumed silica slurry to reduce defects by enhancing the repulsive force against slurry particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polishing pads are used in CMP processes, then polishing can be performed, but high defect rates (scratches and chatter marks) occur on semiconductor wafers
Solution Approach 1:
The patent modifies the chemical composition parameters of the polyurethane by incorporating silane repeating units with specific structures (Formula 1) into the main chain. This chemical parameter change alters the surface properties of the polishing pad, creating a repulsive force against slurry particles and preventing defect formation while maintaining polishing effectiveness
Solution Approach 2:
The invention creates a composite polyurethane structure by integrating silane repeating units into the polyurethane main chain. This composite material approach combines the mechanical properties of polyurethane with the surface characteristics of silane groups, achieving both effective polishing and defect reduction
2Object-affected harmful factors
If the polishing pad structure is modified to reduce defects, then defect rate decreases, but removal rate and cutting rate must be maintained
Solution Approach 1:
The patent applies local quality modification by incorporating silane repeating units specifically into the polishing pad's surface structure. This localized chemical modification affects only the surface interaction properties, creating repulsive forces against slurry particles at the contact interface, while the bulk polyurethane structure maintains its mechanical properties for effective material removal
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 proposed polishing pad significantly reduces defects on silicon wafers by 80% or more while maintaining removal and cutting rates comparable to conventional pads, ensuring high polishing quality.
Implementation Method 1
designed to have specific contact angle differences with pure water and fumed silica slurry, and a foamed body structure, is used in conjunction with a fumed silica slurry to reduce defects by enhancing the repulsive force against slurry particles
Implementation Method 2
a foamed body structure, is used in conjunction with a fumed silica slurry to reduce defects
Data Source
AI summary
A polishing pad includes a polyurethane, wherein the polyurethane includes in its main chain a silane repeating unit represented by Formula 1, wherein the number of defects on a substrate after polishing with the polishing pad and a fumed silica slurry is about 40 or lesswherein R11 and R12 are each independently hydrogen or C1-C10 alkyl groups, and n is an integer from 1 to 30.