Retaining Ring Inserts for CMP Rigidity and Heat Dissipation
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Solution Overview
Problem
Chemical mechanical polishers face challenges in minimizing contamination and exposure to mobile ions during the polishing of semiconductor wafers, particularly when using conductive and non-conductive materials, as existing metallic components react with chemicals and introduce contaminants.
Innovation Solution
A one-piece retaining ring assembly with inserts made of more rigid and heat-conductive materials than the ring itself, positioned in the outer portion to avoid chemical contact and enhance rigidity and heat dissipation, while maintaining a smooth surface and reducing contamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic components are used in the chemical mechanical polishing equipment, then strength and rigidity are improved, but chemical reactivity increases leading to contamination and mobile ion exposure
Solution Approach 1:
The patent extracts the metallic components from the polishing equipment, specifically removing all exposed metal surfaces from the chemical mechanical polishing environment. The retaining ring is constructed entirely from non-reactive materials such as PEEK or PTFE, eliminating the source of metal contamination and mobile ion exposure while maintaining structural integrity through material selection.
Solution Approach 2:
The patent changes the material parameters of the retaining ring from metallic to non-metallic polymers with appropriate mechanical properties. By selecting materials like PEEK or PTFE that have sufficient strength and rigidity despite being non-metallic, the system achieves both contamination prevention and structural performance.
2Object-affected harmful factors
If non-metallic materials are used to replace metal components, then chemical reactivity is reduced, but rigidity and heat dissipation capability deteriorate
Solution Approach 1:
The patent employs composite material construction for the retaining ring, combining non-reactive polymer materials (PEEK or PTFE) with reinforcing elements or structural designs that enhance rigidity. The composite approach allows the base material to provide chemical inertness while additional structural features compensate for the lower inherent rigidity of non-metallic materials.
3Object-affected harmful factors
If non-metallic materials are used to replace metal components, then chemical reactivity is reduced, but heat dissipation capability deteriorates
Solution Approach 1:
The patent introduces thermal management features as intermediaries to compensate for the poor heat dissipation of non-metallic materials. This may include integrated cooling channels, thermal coupling elements, or design features that facilitate heat removal from the polishing interface, allowing the use of non-reactive materials without compromising thermal management.
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 effectively limits exposure to mobile ions, maintains rigidity and heat dissipation, and reduces contamination, improving the overall chemical mechanical polishing process by using inserts that are more resistant to deformation and chemical reactivity.
Implementation Method 1
inserts made of more rigid and heat-conductive materials than the ring itself
Data Source
AI summary
Retaining rings are presented with specially designed inserts that increase rigidity and improve heat dissipation. Inserts that are more rigid, and that have better ability to conduct heat, are inserted into pockets positioned along the outer portion of the rings. The pockets do not compromise the upper, lower or inner portion of the rings. Because the inserts are more rigid than the material used in the body of the ring, they absorb the deforming forces resulting from fastening the ring to the carrier head. Because they are better conductors than the material used in the body of the ring, the ring is better able to dissipate heat generated during polishing. Moreover, because the inserts are positioned in the outer portion of the ring, the inserts are not exposed to the polishing surface during polishing and therefore are less likely to react undesirably with the chemicals used during polishing.