Spring Retained Contact Pad for Thermal Cycling
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Solution Overview
Problem
Conventional composite end effectors face challenges in securely attaching ceramic contact pads to metal end effector bodies due to differences in thermal expansion and tensile strength, leading to potential cracking, loose fasteners, and particulate dispersion during thermal cycling and substrate handling.
Innovation Solution
A composite end effector design featuring a retaining spring with through-holes and channels that securely attaches contact pads to the end effector body, allowing for relative thermal expansion and contraction without loosening, and collects particulate matter to prevent dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If threaded fasteners are used to attach ceramic contact pads to metal end effector bodies, then the connection is secure and rigid, but the thermal cycling causes cracking of contact pads and loosening of fasteners
Solution Approach 1:
The patent changes the attachment mechanism from rigid threaded fasteners to a spring-based system that accommodates thermal expansion parameter changes. The spring retaining arms flex to absorb dimensional changes during thermal cycling, preventing contact pad cracking and fastener loosening while maintaining secure attachment.
Solution Approach 2:
The patent uses composite construction with metal end effector bodies and ceramic contact pads, each material optimized for its function. The metal body provides thermal conductivity and structural support, while the ceramic pads provide wear resistance at substrate contact points.
2Ease of manufacture
If press-fit pads are used to attach contact pads, then the attachment is simple, but the contact pads cannot be easily removed when replacement is necessary
Solution Approach 1:
The patent employs a dynamic spring-based retaining system that allows easy removal and reinstallation of contact pads. The spring retaining arms can be compressed to release the contact pad and return to their original position to secure the new pad, providing both manufacturing simplicity and ease of replacement.
3Strength
If retaining rings are used to clamp pads to the end effector, then the pads are securely held, but particles are generated due to relative motion which contaminates substrates
Solution Approach 1:
The patent extracts the harmful particle-generating clamping action of traditional retaining rings and replaces it with a spring-based retaining arm system. The spring retaining arms engage with slots in the contact pad, providing secure retention without the sliding friction that generates contaminating particles.
4Productivity
If ceramic contact pads are removably attached to metal end effector bodies, then only worn pads need replacement, but the different thermal expansion and tensile strength properties make secure connection difficult
Solution Approach 1:
The patent changes from rigid mechanical connections to a spring-based system that adapts to thermal expansion parameter changes. The spring retaining arms flex during thermal cycling to accommodate the different expansion coefficients of ceramic and metal, maintaining secure connection while enabling efficient pad replacement.
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 design ensures secure, removable contact pads that withstand thermal cycling without damage, maintaining attachment integrity and preventing particulate contamination of substrates.
Implementation Method 1
a spring having a pair of retaining arms extending from the spring pocket through the through-holes and into the contact pad pocket. The retaining arms may extend at least partially into the at least one retaining channel of the contact pad
Implementation Method 2
the arrangement for attaching the material-contacting portions to the non-material-contacting portion permits relative thermal expansion and contraction without loosening
Data Source
AI summary
An end effector is disclosed for use in substrate processing. The end effector includes a effector body portion, a contact pad pocket formed in the end effector body, a spring retaining pocket formed in the end effector body adjacent the contact pad pocket and extending to an edge of the end effector body, and a pair of through-holes extending from the spring retaining pocket to the contact pad pocket. The end effector can include a contact pad seated within the contact pad pocket, the contact pad having at least one retaining channel formed therein, and a retaining spring having a pair of retaining arms extending from the retaining spring pocket through the through-holes and into the contact pad pocket. The retaining arms may extend at least partially into the at least one retaining channel of the contact pad and may thereby restrict movement of the contact pad.