CMP Polishing Pad Protruding Structures with Engineered Voids
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Solution Overview
Problem
Conventional chemical mechanical polishing (CMP) pads face challenges in managing temperature and maintaining mechanical properties during polishing, leading to potential defects and inefficiencies due to solid protrusions that can cause frictional heating and irreversible chemical reactions.
Innovation Solution
A CMP pad design featuring protruding structures with central cavities and side openings that allow for efficient fluid management, reducing temperature increase and enabling a harder top surface while maintaining a lower overall compressive modulus, thus improving conformation to the substrate and increasing removal rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If solid protrusions are used in CMP pads, then polishing surface area is increased, but frictional heating increases causing temperature rise and potential defects
Solution Approach 1:
The patent applies porous materials by incorporating void spaces within the protruding structures of the polishing pad. These voids allow slurry to penetrate and flow through the pad structure, facilitating heat dissipation and reducing frictional heating during polishing operations while maintaining adequate polishing surface area.
Solution Approach 2:
The patent utilizes hydraulic principles by allowing slurry (fluid) to flow through the void spaces in the protruding structures. This fluid flow carries away heat generated during polishing and maintains effective temperature control, demonstrating the application of hydraulics in thermal management.
2Productivity
If harder top surface is used, then removal rate is improved, but mechanical integrity and conformation to substrate may be compromised
Solution Approach 1:
The patent applies composite materials by creating a polishing pad with heterogeneous structure - harder protruding structures for high removal rate and a softer base material for mechanical integrity and conformation. This composite structure allows the harder top surface to maintain productivity while the overall structure preserves reliability through the compliant base.
Solution Approach 2:
The patent applies local quality by varying the mechanical properties at different locations within the polishing pad. The protruding structures have different hardness and mechanical properties compared to the base material, allowing each region to perform its specific function - the harder protrusions provide high removal rate where contact occurs, while the softer base provides overall conformation and mechanical integrity.
3Strength
If protruding structures are made solid, then structural strength is increased, but deflection increases and polishing area consistency deteriorates during wear
Solution Approach 1:
The patent applies porous materials by incorporating void spaces within the protruding structures. These voids reduce the effective mass and moment of inertia of the protrusions, thereby reducing deflection under load while maintaining structural strength through optimized geometry. The porous structure also allows for more consistent polishing area as the protrusions wear.
Solution Approach 2:
The patent applies dimensional changes by moving from solid three-dimensional protrusions to protrusions with internal void spaces. This dimensional reconfiguration reduces material volume and deflection while maintaining external geometry and polishing surface area, thereby improving polishing area consistency during wear.
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 pad design achieves higher removal rates and reduced defectivity by managing temperature and maintaining mechanical integrity, with protruding structures showing less deflection and maintaining consistent polishing area as they wear down, resulting in improved polishing efficiency and reduced thermal-induced defects.
Implementation Method 1
protruding structures with central cavities and side openings that allow for efficient fluid management, reducing temperature increase
Implementation Method 2
managing temperature and maintaining mechanical integrity, with protruding structures showing less deflection and maintaining consistent polishing area as they wear down, resulting in improved polishing efficiency and reduced thermal-induced defects
Data Source
AI summary
A polishing pad useful in chemical mechanical polishing comprises a base pad having a top side, and a plurality of protruding structures on the top side of the base pad, each of the protruding structures having a body, where the body has (i) an exterior perimeter surface defining an exterior shape of the protruding structure, (ii) an interior surface defining a central cavity and (iii) a top surface defining an initial polishing surface area, wherein the body further has openings in it from the cavity to the exterior perimeter surface.