Urethane Foam Pad Dressing with Mixed Grit Diamond Abrasives
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Urethane foam pads used in wafer polishing face issues when dressed with either low-grit or high-grit diamond abrasive grains, leading to either closed holes and reduced slurry retention or insufficient surface roughening, resulting in unfavorable wafer flatness and decreased productivity.
Innovation Solution
A dressing apparatus with a support holding diamond abrasive grains of multiple grit sizes, including high-grit #170 or more and low-grit #140 or less, ensures that all dressing surfaces are on the same plane, allowing simultaneous sliding contact to effectively roughen the urethane foam pad without closing holes, thus extending dressing intervals and improving productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If low-grit diamond abrasive grains (#60 or #100) are used for dressing the urethane foam pad, then the diamond abrasive grains are strongly caught in holes of the foaming part causing the urethane resin to be stretched, but the holes of the foaming part are unfavorably closed leading to reduced slurry retention
Solution Approach 1:
The patent applies local quality by using different grit sizes of diamond abrasive grains at different locations on the dressing apparatus. Specifically, low-grit grains (#60-#100) are used in regions where surface roughening is needed, while high-grit grains (#200-#325) are used in regions where hole closure prevention is critical. This spatial differentiation of abrasive grain properties allows simultaneous achievement of surface roughening and hole preservation.
Solution Approach 2:
The dressing apparatus is segmented into multiple dressing surfaces, each equipped with diamond abrasive grains of different grit sizes. The support structure divides the dressing function into separate zones: one zone with low-grit grains for roughening and another zone with high-grit grains for preventing hole closure. This segmentation allows independent optimization of each zone's function.
2Reliability
If high-grit diamond abrasive grains (#325) are used for dressing the urethane foam pad, then the holes of the foaming part are not closed, but the surface of the foaming part cannot be sufficiently roughened resulting in shorter dressing intervals
Solution Approach 1:
The patent applies local quality by using different grit sizes of diamond abrasive grains at different locations on the dressing apparatus. Specifically, low-grit grains (#60-#100) are used in regions where surface roughening is needed, while high-grit grains (#200-#325) are used in regions where hole closure prevention is critical. This spatial differentiation of abrasive grain properties allows simultaneous achievement of surface roughening and hole preservation.
Solution Approach 2:
The dressing apparatus is segmented into multiple dressing surfaces, each equipped with diamond abrasive grains of different grit sizes. The support structure divides the dressing function into separate zones: one zone with low-grit grains for roughening and another zone with high-grit grains for preventing hole closure. This segmentation allows independent optimization of each zone's function.
3Manufacturing precision
If multiple dressing operations with different grit sizes are performed sequentially, then the surface can be sufficiently roughened and holes can be preserved, but the workability is poor and the time for dressing increases
Solution Approach 1:
The patent merges multiple dressing functions into a single integrated apparatus. Multiple dressing surfaces with different grit sizes are combined on one support structure, allowing simultaneous execution of roughening and hole-preserving functions in a single dressing operation. This eliminates the need for sequential dressing steps and reduces total dressing time.
Solution Approach 2:
The dressing apparatus is designed with multi-functionality by incorporating dressing surfaces with different grit sizes on a single support. This universal apparatus can perform both surface roughening and hole preservation functions simultaneously, eliminating the need for separate dressing operations and different apparatus configurations.
4Device complexity
If diamond abrasive grains with different grain diameters are arranged on one support with fixed height, then the apparatus structure is simple, but the height positions of dressing surfaces are different causing contact amount to vary depending on grain diameter
Solution Approach 1:
The patent applies dynamics by making the support structure adjustable rather than fixed. The support can be dynamically positioned to control the height of each dressing surface, allowing optimization of contact between different grit sizes and the urethane foam pad. This dynamic adjustment ensures uniform contact across all abrasive grains regardless of their different diameters.
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 configuration enables one-time dressing that maintains surface roughness and slurry retentivity, significantly improving wafer flatness and reducing the frequency of dressing, thereby enhancing productivity in wafer manufacturing.
Implementation Method 1
a dressing apparatus for dressing a urethane foam pad, for use in polishing, by bringing diamond abrasive grains into sliding contact with the urethane foam pad
Data Source
AI summary
A dressing apparatus for dressing a urethane foam pad, for use in polishing, by bringing diamond abrasive grains into sliding contact with the urethane foam pad, includes a support for holding the grains. The grains have multiple grit sizes, and include a high-grit diamond abrasive grain with a grit size of #170 or more and a low-grit diamond abrasive grain with a grit size of #140 or less. The grains are held by the support such that height positions of dressing surfaces of the grains are on the same plane. The dressing surfaces come into contact with the urethane foam pad. As a result, a dressing apparatus is capable of sufficiently roughening the surface of the urethane foam pad by one-time dressing without closing holes of the foaming part of the urethane foam pad, enabling short dressing time, long dressing interval, and inhibition of lowering of productivity.