Segmented Clamp Ring Geometry to Prevent PVD Substrate Sticking
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Solution Overview
Problem
In physical vapor deposition (PVD) processes, substrates often stick to clamp rings, leading to damage when separated, resulting in reduced process yield and the need for reprocessing or scrapping, which decreases the number of substrates that can be processed per hour.
Innovation Solution
A clamp ring with an annular circular body and radially inwardly extending pads and alignment marks is designed to minimize substrate-clamp ring contact, featuring an inner diameter that satisfies specific geometric equations to reduce the likelihood of sticking, thereby preventing damage during separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If substrates are held in place by clamp rings during PVD processing, then substrates can be securely positioned and processed, but substrates may stick to the clamp ring causing damage during separation
Solution Approach 1:
The clamp ring is divided into multiple discrete pads rather than a continuous contact surface. Each pad is separated from adjacent pads, creating distinct contact zones. This segmentation reduces the overall contact area between the substrate and clamp ring, minimizing the risk of sticking while maintaining secure positioning at specific points.
Solution Approach 2:
The clamp ring features pads with specific local properties - they are positioned at predetermined locations around the inner periphery and extend radially inward by a controlled distance. The pads create localized contact zones with optimized geometry, where the inner edges of opposite pads are spaced to provide sufficient clearance. This local quality control ensures reliable positioning without excessive contact that would cause sticking.
2Stability of the object's composition
If substrates are securely held by clamp rings, then processing stability is improved, but separation becomes difficult and may damage deposited films
Solution Approach 1:
By segmenting the clamp ring into discrete pads rather than using a continuous clamping surface, the substrate is held at multiple isolated points. This provides sufficient stability during processing while allowing easy separation, as the segmented contact points do not create large-area adhesion that would damage films during removal.
Solution Approach 2:
The pads extend radially inward a distance that provides adequate clamping force for processing stability, but not so far as to create excessive contact. The inner edges of opposite pads are spaced to provide just enough clearance to prevent sticking while maintaining firm holding during the deposition process, enabling clean separation afterward.
3Reliability
If clamp ring contact area with substrate is increased for secure holding, then positioning reliability improves, but sticking risk increases reducing process yield
Solution Approach 1:
The clamp ring contact area is segmented into multiple discrete pads distributed around the inner periphery. This provides reliable positioning through distributed point contacts while minimizing the total contact area, thereby reducing sticking risk and maintaining high process yield without sacrificing positioning reliability.
Solution Approach 2:
The pads are positioned at specific locations with controlled dimensions - extending radially inward by a predetermined distance with inner edges spaced to provide clearance. This local quality optimization ensures reliable substrate positioning at critical points while limiting overall contact area to prevent sticking, thus protecting process yield.
4Object-affected harmful factors
If clamp ring is designed with larger inner diameter for substrate clearance, then sticking is reduced, but positioning precision may be compromised
Solution Approach 1:
Rather than increasing the overall inner diameter of the clamp ring, the invention segments the contact area into discrete pads. This allows the pads to be positioned at optimal locations for precision while maintaining sufficient spacing between them and the substrate edge to prevent sticking, achieving both goals simultaneously.
Solution Approach 2:
The pads are positioned at predetermined locations around the inner periphery with controlled radial extension and spacing. This creates localized precision contact zones that ensure accurate substrate positioning while the spacing between pad inner edges provides clearance to prevent sticking, balancing precision and sticking prevention.
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 clamp ring design effectively reduces the risk of substrate sticking, minimizing damage and increasing the throughput of the PVD chamber by allowing for safer separation without damaging the deposited films.
Implementation Method 1
A clamp ring with an annular circular body and radially inwardly extending pads and alignment marks is designed to minimize substrate-clamp ring contact, featuring an inner diameter that satisfies specific geometric equations to reduce the likelihood of sticking
Data Source
AI summary
A clamp ring including an inner periphery of increased diameter at locations where inwardly extending tabs are not located reduces the risk a workpiece that is placed in close proximity to the clamp ring or which contacts the clamp ring during processing will stick to the clamp ring.