Adjustable PVD Clamp Assembly for Low-Shadow Substrate Holding
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Solution Overview
Problem
Existing substrate securing methods in PVD processes face challenges such as substrate damage from excessive force, contamination from gaskets, and the shadowing effect caused by clamps, which affect the uniformity of thin film deposition.
Innovation Solution
A clamp assembly comprising a main clamp, a sub-clamp with a tapered inner edge, a polymer gasket, and a leaf spring or compression spring arrangement that reduces pressure on the substrate, minimizes contamination, and mitigates the shadowing effect by allowing for adjustable positioning and reduced height profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clamps are used to secure the substrate tightly to prevent movement, then substrate stability is improved, but substrate damage may occur due to excessive force
Solution Approach 1:
A gasket is introduced as an intermediary element between the clamp and the substrate. The gasket distributes the clamping force over a larger area and provides a compliant interface that prevents direct contact between the rigid clamp and the fragile substrate, thereby maintaining substrate stability while avoiding damage
Solution Approach 2:
The clamp design incorporates adjustable positioning capabilities that allow the clamping force and contact points to be optimized. By changing the parameters of clamping force magnitude and distribution, the system achieves adequate substrate fixation without applying excessive force that could cause damage
2Object-affected harmful factors
If gaskets are used in clamps to secure the substrate, then substrate damage is reduced, but contamination of the substrate occurs
Solution Approach 1:
The gasket material is selected to be chemically inert and compatible with the vacuum environment and deposition process. This inert gasket material does not outgas contaminants or react with the substrate or deposited films, thereby preventing contamination while maintaining the protective function of the gasket
Solution Approach 2:
The clamp assembly uses composite material construction, combining the structural clamp body with a specialized gasket material that provides both mechanical compliance and chemical inertness. This composite approach allows the system to achieve both damage prevention and contamination reduction
3Reliability
If clamps are positioned close to the substrate to secure it effectively, then substrate stability is improved, but shadowing effect increases blocking vapor stream
Solution Approach 1:
The clamp assembly is segmented into multiple components including the main clamp body, sub-clamp elements, and gasket. This segmentation allows the clamping function to be distributed across multiple points, enabling effective substrate fixation while minimizing the projected area of any single component that could cause shadowing
Solution Approach 2:
The clamp design utilizes three-dimensional positioning and adjustable orientation to secure the substrate. By operating in multiple spatial dimensions rather than requiring a single large clamp structure, the system achieves effective substrate fixation while minimizing the shadowing footprint in the vapor deposition path
4Reliability
If large clamps are used to secure the substrate, then substrate stability is improved, but shadowing effect and contamination risk increase
Solution Approach 1:
The substrate securing function is divided into multiple smaller clamping points distributed around the substrate periphery. This segmentation achieves equivalent or superior stability compared to a single large clamp while significantly reducing the shadowing effect, as each small clamp component casts a smaller shadow
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 assembly effectively secures substrates without damaging them, reduces contamination, and enhances deposition uniformity by distributing force evenly and minimizing the shadowing effect, ensuring stable and uniform thin film deposition.
Implementation Method 1
a leaf spring secured to the sub-clamp by at least one of a plurality of fasteners
Implementation Method 2
a compression spring disposed coaxially about the fastener
Implementation Method 3
a sub-clamp having a tapered inner edge
Data Source
AI summary
Embodiments of the disclosure provided herein include an apparatus for securing a substrate in a plasma processing system. The apparatus includes a clamp assembly having a main clamp, a sub-clamp having a tapered inner edge, a gasket disposed within the sub-clamp, the gasket being proximate to the tapered inner edge having a gasket contact surface configured to contact a substrate, and a leaf spring secured to the sub-clamp by at least one of a plurality of fasteners. In another embodiment, a clamp assembly has a main clamp, a sub-clamp having a tapered inner edge, the sub-clamp secured to the main clamp by a fastener, a gasket having a gasket contact surface, and a compression spring disposed coaxially about the fastener.