Annular Polishing Pad Control for Wafer Edge Precision
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Solution Overview
Problem
Existing substrate polishing processes lack the ability to control polishing for each region, leading to increased failure rates and reduced manufacturing yield, particularly at the edge regions of substrates.
Innovation Solution
A substrate polishing apparatus and method that divides the polishing pad into multiple annular regions with varying properties, allowing for targeted maintenance and control of polishing based on substrate surface conditions, thereby improving polishing performance and reducing edge region defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single uniform polishing pad is used for the entire substrate surface, then the device complexity is reduced, but the manufacturing precision and reliability deteriorate due to inability to control polishing for each region
Solution Approach 1:
The polishing pad is divided into multiple annular regions (first annular region, second annular region, third annular region) with different properties. Each region can be independently controlled and maintained, allowing different polishing conditions for different substrate areas while maintaining an integrated pad structure.
Solution Approach 2:
Different annular regions of the polishing pad are assigned different properties (e.g., different materials, hardness, or surface characteristics) to match the specific polishing requirements of different substrate regions. The first annular region may have different properties than the second and third annular regions to optimize polishing for each specific area.
2Reliability
If the polishing pad is divided into multiple annular regions with different properties, then the manufacturing precision and reliability are improved, but the device complexity increases
Solution Approach 1:
The polishing pad is segmented into multiple annular regions that can be independently managed. This allows targeted maintenance of specific regions (e.g., replacing only the worn first annular region) while maintaining the integrity of other regions, thereby improving reliability without requiring complete pad replacement.
Solution Approach 2:
Different annular regions are configured with different parameters (material composition, hardness, surface roughness) to optimize polishing performance for specific substrate areas. The first annular region may have different material properties than the second and third annular regions to address specific reliability issues at different locations.
3Area of stationary object
If the outer annular region has a larger width in radius direction, then the polishing coverage is increased, but the manufacturing precision deteriorates due to increased difficulty in controlling edge region polishing
Solution Approach 1:
The width in the radius direction of the first annular region is made smaller than that of the second and third annular regions. This creates a narrower outer annular region with enhanced polishing precision for edge areas, while the wider inner regions provide broader coverage for the central substrate areas.
Solution Approach 2:
The polishing pad is segmented into annular regions with different width characteristics. The first annular region has a smaller radial width to provide precise control for edge polishing, while the second and third annular regions have larger radial widths to maintain overall polishing coverage efficiency.
4Reliability
If maintenance is performed on the entire polishing pad, then the reliability is improved, but the productivity decreases due to complete pad replacement requirement
Solution Approach 1:
The polishing pad is segmented into multiple annular regions that can be independently maintained. When wear or damage occurs, only the affected region (e.g., first annular region) needs to be replaced or maintained, while the other regions continue to function, thereby maintaining productivity while improving reliability.
Solution Approach 2:
Instead of discarding the entire polishing pad when one region is worn, the invention allows selective replacement or recovery of only the worn annular region. The other regions of the pad are recovered and continued to use, minimizing waste and maintaining manufacturing productivity.
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
Enhances polishing control and reduces failure rates, increasing manufacturing yield by optimizing polishing pad conditions and maintaining substrate edge quality.
Implementation Method 1
rotating each of the substrate and a polishing pad of the substrate polishing apparatus; allowing a bottom surface of the substrate to contact a top surface of the polishing pad
Data Source
AI summary
Disclosed is a substrate polishing method comprising placing a substrate into a substrate polishing apparatus, rotating each of the substrate and a polishing pad of the substrate polishing apparatus, allowing a bottom surface of the substrate to contact a top surface of the polishing pad, and determining whether the polishing pad would benefit from maintenance. The polishing pad includes a plurality of annular regions that are homocentric with a central point of the top surface of the polishing pad. The step of determining whether the polishing pad would benefit from maintenance includes ascertaining a state of the bottom surface of the substrate, and selecting one of the plurality of annular regions by using information about the state of the bottom surface of the substrate. The one of the plurality of annular regions would benefit from maintenance.