Dual-Hardness Rubber Membrane for Uniform CMP Pressure
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Solution Overview
Problem
Existing elastic membranes in chemical mechanical polishing (CMP) systems face challenges in achieving uniform film-thickness distribution due to variations in rigidity and flexibility, leading to non-uniform polishing rates and potential deformation during the polishing process.
Innovation Solution
An elastic membrane composed of two rubber structures with different hardnesses, a first rubber structure with higher rigidity and a second rubber structure with lower rigidity, are integrally formed to provide appropriate rigidity and flexibility for each portion, preventing deformation and ensuring uniform pressure distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single rubber material is used for the elastic membrane, then the manufacturing process is simple, but the rigidity and flexibility are insufficient for different portions leading to non-uniform polishing pressure
Solution Approach 1:
The elastic membrane is divided into multiple regions with different rubber materials having distinct rigidity and flexibility characteristics. The contact portion uses a softer rubber for flexibility, while partition walls use a stiffer rubber for structural support. This local differentiation enables each region to perform its specific function optimally, achieving uniform polishing pressure distribution.
Solution Approach 2:
The elastic membrane employs a composite structure combining at least two different rubber materials with different hardness values. This composite approach allows the membrane to simultaneously exhibit both flexibility and rigidity in different locations, resolving the contradiction between uniform pressure distribution and structural complexity.
2Reliability
If the contact portion has high rigidity to prevent twisting and wear, then durability is improved, but flexibility is reduced causing non-uniform pressure distribution
Solution Approach 1:
Different rubber materials with different mechanical properties are assigned to different regions: the contact portion uses a softer, more flexible rubber to ensure uniform pressure distribution and ease of operation, while partition walls use a stiffer rubber to provide structural support and prevent deformation.
3Stress or pressure
If partition walls are made flexible to expand downward when gas is supplied, then pressure transmission is improved, but they may contact with retainer ring causing deformation
Solution Approach 1:
The partition walls are constructed from a stiffer rubber material compared to the contact portion. This material differentiation allows partition walls to maintain their shape and resist outward inclination while still expanding downward sufficiently to transmit pressure uniformly to the workpiece surface.
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 integrated rubber structures enable uniform film-thickness distribution and stable polishing pressure, preventing deformation and wear, while improving productivity through reduced process steps and adhesive use.
Implementation Method 1
a flexible material, such as rubber, is generally used for the elastic membrane
Implementation Method 2
The elastic membrane is composed of a first rubber structure having a first hardness and a second rubber structure having a second hardness lower than the first hardness
Data Source
AI summary
An elastic membrane having a physical property required for each portion of the elastic membrane and capable of uniformly polishing a workpiece is disclosed. The elastic membrane includes: a contact portion having a workpiece pressing surface for pressing a workpiece against a polishing surface; and a partition wall extending upward from the contact portion and forming a pressure chamber. The contact portion and at least a part of the partition wall are composed of a first rubber structure and a second rubber structure which are integrally formed, the first rubber structure has a first hardness, and the second rubber structure has a second hardness lower than the first hardness, the first rubber structure includes the workpiece pressing surface, and the second rubber structure includes the at least a part of the partition wall.