Buff Pad with Segmented Hardness for Uniform Substrate Polishing
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Solution Overview
Problem
Conventional substrate buffing technologies face issues with precise control of the contact state between the buff pad and the processing object, leading to non-uniform buffing, pressure concentration, and poor cleaning efficiency, particularly in chemical mechanical polishing processes.
Innovation Solution
A buff pad with distinct characteristics between its inner and outer parts, including differences in material, hardness, density, and pore structure, is used in conjunction with a buffing apparatus featuring an internal liquid supply system to ensure uniform process liquid distribution and pressure control, enhancing buffing efficiency and preventing substrate damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single uniform buff pad is used for the entire substrate surface, then the device complexity is reduced, but the manufacturing precision and uniformity of buffing rate deteriorate due to pressure concentration and non-uniform contact state
Solution Approach 1:
The buff pad is divided into multiple regions with different characteristics (e.g., different hardness, porosity, or material composition) to address the contradiction. This segmentation allows each region to perform its specific function optimally, improving overall buffing uniformity without significantly increasing device complexity.
Solution Approach 2:
Different parts of the buff pad are given different local properties (such as varying hardness or porosity) to match the specific requirements of different substrate areas. This local quality variation enables precise control of contact pressure and process liquid distribution, resolving the uniformity issue while maintaining a relatively simple overall structure.
2Device complexity
If process liquid is not sufficiently supplied at the interface of substrate and contact member, then the device complexity is reduced, but the productivity and cleaning efficiency deteriorate
Solution Approach 1:
The buff pad incorporates porous materials that automatically absorb and distribute process liquid to the substrate interface through capillary action. This eliminates the need for complex external liquid supply systems while ensuring sufficient liquid presence at the contact interface, thereby maintaining high buffing speed and cleaning efficiency.
Solution Approach 2:
The buff pad structure itself provides the liquid distribution function through its porous structure, making the system self-sufficient. The porous material automatically wicks and distributes process liquid where needed without requiring additional pumps, nozzles, or control systems, thus maintaining simplicity while improving productivity.
3Productivity
If contact pressure is increased to improve cleaning efficiency, then the productivity is improved, but the substrate damage increases
Solution Approach 1:
The buff pad uses local quality variation with different hardness levels in different regions. Softer regions provide gentle contact for delicate areas, reducing substrate damage, while harder regions provide necessary pressure for robust cleaning where needed. This local differentiation enables high cleaning efficiency without excessive substrate damage.
Solution Approach 2:
The invention changes the physical parameters of the buff pad (hardness, porosity, elasticity) to optimize the contact pressure characteristics. By selecting materials with appropriate parameters, the system achieves sufficient cleaning pressure while inherently limiting peak pressures that could cause substrate damage, thus improving productivity without increasing harmful effects.
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 solution enables precise control of the buffing process, improving the uniformity of the buffing rate, reducing substrate damage, and enhancing the cleaning efficiency by maintaining a consistent process liquid supply, thereby addressing the limitations of existing technologies.
Implementation Method 1
by injecting a fluid to the space and bending the elastic member to a processing object side, the pad is pressurized to the processing object
Implementation Method 2
bending the elastic member to a processing object side
Implementation Method 3
By pressing the corner of the pad to the curved surface of the grindstone while rotating the pad, the processing unit chamfers the corner of the pad
Data Source
AI summary
A buffing module for buffing a substrate is provided. The buffing module comprises a buff table for supporting the substrate, the buff table being rotatable; and a buff head to which a buff pad is attached, being rotatable and movable in a direction of approaching the buff table and a direction of moving away from the buff table. The buff pad includes a first part and a second part arranged so as to surround the first part on an outer side of the first part, the first part and the second part have different characteristics from each other.