EACMP Polishing Pad With Interlaced Electrodes
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Solution Overview
Problem
Conventional Chemical Mechanical Polishing (CMP) techniques face challenges in reducing residual stresses and defects, particularly when dealing with copper and low-k materials, and struggle to maintain uniform polishing particle sizes, leading to surface scratches and uneven wafer planarization.
Innovation Solution
An electrically assisted chemical-mechanical planarization (EACMP) system and method utilizing a novel polishing pad structure with interlaced positive and negative electrodes, inducing electro-osmosis and electrochemical effects to enhance material removal and particle uniformity, featuring a non-conductive main polishing body with metal bottom portions and narrow slots for fluid and electrical communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CMP technique is used for planarization, then the wafer surface can be flattened, but residual stresses and defects remain in the copper and low-k materials
Solution Approach 1:
The patent applies electrochemical parameters (electric current, electrode potential) to change the material removal mechanism from purely mechanical to electrochemical-assisted mechanical, thereby reducing residual stresses and defects while maintaining planarization quality
Solution Approach 2:
The polishing pad uses composite structure with conductive and non-conductive layers, and the polishing process combines electrochemical reaction with mechanical abrasion, creating a composite polishing system that addresses both planarization and defect reduction
2Manufacturing precision
If conventional CMP is applied to copper and low-k materials, then global planarization is achieved, but scratches and surface defects occur
Solution Approach 1:
The polishing pad has localized conductive regions (metal bottom portions in cavities) that create localized electrochemical zones, allowing different polishing characteristics in different areas to prevent scratches while maintaining global planarization
Solution Approach 2:
The patent replaces part of the mechanical polishing action with electrochemical dissolution, reducing the mechanical stress that causes scratches on copper and low-k materials while maintaining material removal effectiveness
3Productivity
If interlaced positive and negative electrodes are connected to metal bottom portions in cavities, then electro-osmosis and electrochemical effects are produced, but device complexity increases
Solution Approach 1:
The polishing pad is segmented into multiple cavities with metal bottom portions, each acting as an independent electrochemical cell, allowing the complex electrochemical function to be distributed across many simple modular units
Solution Approach 2:
The metal bottom portions serve multiple functions: they act as electrodes for electrochemical reaction, provide structural support, and facilitate slurry distribution, reducing the need for separate components and simplifying the overall structure
4Productivity
If electrochemical effects are induced in polishing, then removal rate increases, but maintaining uniform polishing particle sizes becomes challenging
Solution Approach 1:
The interlaced arrangement of positive and negative electrodes creates periodic electrochemical zones that continuously regenerate polishing particles through controlled electrochemical reactions, maintaining uniform particle sizes while sustaining high removal rate
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 EACMP system effectively reduces residual stresses and defects, increases removal rate, and maintains uniform polishing particle sizes, improving the planarization process by utilizing electrochemical and mechanical polishing in conjunction with electro-osmosis and electrochemical effects.
Implementation Method 1
electrically and alternatively, e.g. interlacedly, connecting the positive and negative electrodes of the power supply to the metal bottom portions respectively in the cavities on the polishing pad to produce the electro-osmosis and electrochemical effects
Implementation Method 2
electrically and alternatively, e.g. interlacedly, connecting the positive and negative electrodes of the power supply to the metal bottom portions respectively in the cavities on the polishing pad to produce the electro-osmosis and electrochemical effects
Implementation Method 3
which reduces residual stress and defects
Data Source
AI summary
A novel polishing pad is described. The polishing pad includes a base plate, a main polishing body, a plurality of metal bottom portions, a positive electrode conductive wire and a negative electrode conductive wire. The main polishing body made from a non-conductive material and disposed on the base plate includes a plurality of cavities thereon. The metal bottom portions are disposed in the cavities with each of the cavities having one of the metal bottom portions therein. The positive electrode conductive wire electrically is connected to a positive electrode of a power supply. The negative electrode conductive wire electrically is connected to a negative electrode of the power supply. The positive electrode conductive wire and the negative electrode conductive wire alternatively pass through the base plate and connect to the metal bottom portions respectively.