Replaceable Standoffs for ESC Backside Contamination
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Solution Overview
Problem
Conventional workpiece supports in semiconductor processing suffer from backside contamination due to intimate contact with handling components, leading to particle and metal transfer, and require costly replacement when wear occurs, as integral mesas on the clamping surface are hard and prone to increased contamination.
Innovation Solution
Field-replaceable standoffs made of resilient materials like silicone, which can be selectively affixed to the support surface, creating a buffer between the workpiece and the handling component, reducing contact and wear, and allowing for customized arrangement and easy replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If integral mesas are used on the clamping surface, then wear resistance is improved, but backside contamination increases due to intimate contact
Solution Approach 1:
A resilient material layer is introduced as an intermediary between the hard mesa structure and the workpiece backside. This layer acts as a mediator that prevents direct intimate contact while maintaining the mechanical support function, thereby reducing particle and metal transfer contamination.
Solution Approach 2:
A flexible resilient material layer is applied over the rigid mesa structure. This thin flexible film conforms to the workpiece surface, maintaining contact pressure for support while preventing the hard underlying structure from causing contamination through direct contact.
2Strength
If hard mesas are used for support, then structural strength is improved, but replacement cost increases when wear occurs
Solution Approach 1:
The support structure is segmented into two independent parts: a permanent hard mesa structure providing structural strength, and a replaceable resilient material layer providing contamination protection. When the resilient layer wears, only that layer needs replacement rather than the entire support structure.
Solution Approach 2:
The resilient material layer is designed as a consumable component that can be easily replaced. This disposable-like approach allows frequent replacement of the wear-prone soft layer without replacing the expensive hard mesa structure, reducing overall operational costs.
3Object-affected harmful factors
If resilient material is applied, then backside contamination is reduced, but customization flexibility is limited
Solution Approach 1:
The resilient material can be applied with varying properties in different regions to match specific workpiece requirements. Different areas can have different material characteristics or thicknesses, allowing customization for different workpiece types while maintaining the contamination protection benefit.
Solution Approach 2:
The resilient material layer provides dynamic adaptability through its compliance, automatically conforming to different workpiece geometries and surface conditions. This inherent flexibility allows the same basic structure to adapt to various workpiece types without requiring rigid customization.
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 standoffs significantly mitigate backside contamination and wear, reducing operational costs by allowing for selective replacement and customization, while maintaining optimal performance across various workpiece types and handling components.
Implementation Method 1
The one or more standoffs are comprised of a resilient material
Data Source
AI summary
A workpiece support has a support surface where one or more standoffs are selectively removably coupled to the support surface. The one or more standoffs are operable to support a workpiece at a predetermined standoff distance from the support surface. A gap may be defined between the support surface and the workpiece. The one or more standoffs may be an electrically insulative film, such as a polyimide film that is selectively removably coupled to the support surface by an adhesive. The workpiece support may be an electrostatic chuck (ESC). Electrodes positioned below the support surface may electrostatically attract the workpiece toward the support, where a gas may be introduced in the gap.