Cam Lock Electrode Clamp for Semiconductor Fabrication
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Solution Overview
Problem
The existing methods for bonding silicon electrodes to graphite support rings in semiconductor fabrication processes are time-consuming, prone to thermal stress-induced bowing or cracking, and can lead to contamination, especially in sub-65 nanometer design rules, resulting in non-uniform plasma density and reduced process yields.
Innovation Solution
A cam lock clamp system that uses a stud with disc springs and a camshaft with an eccentric cutout to securely attach the electrode to a backing plate, allowing for thermal expansion differences and minimizing direct pressure on the electrode surface, thus providing a robust, cost-effective, and contamination-free mounting solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermal bonding methods are used to attach silicon electrodes to graphite support rings, then strong bonding strength is achieved, but thermal stress causes bowing or cracking of the electrode
Solution Approach 1:
The bonding interface is segmented into multiple discrete bonding points around the periphery rather than a continuous bonded area. This allows thermal expansion stresses to be distributed and accommodated at each discrete point, preventing cumulative stress buildup that causes bowing or cracking while still achieving strong overall bonding.
Solution Approach 2:
Bonding is applied locally at specific peripheral regions rather than uniformly across the entire electrode surface. This localized bonding approach allows different regions to accommodate thermal expansion differently, reducing stress concentration while maintaining strong attachment where bonding occurs.
2Reliability
If metallurgical bonding is used to attach electrodes, then strong and reliable attachment is achieved, but the process is time-consuming and complex
Solution Approach 1:
The complex thermal metallurgical bonding process is replaced with a simpler mechanical attachment system using discrete bonding points and support structures. This mechanical approach achieves reliable attachment without the time-consuming and complex thermal processing required for traditional metallurgical bonding.
3Strength
If direct clamping pressure is applied to the electrode surface, then secure attachment is achieved, but contamination of the electrode surface occurs
Solution Approach 1:
The clamping function is extracted from direct contact with the electrode surface and transferred to a separate support ring structure. This allows secure attachment through peripheral support without direct clamping pressure on the electrode surface, eliminating the source of surface contamination while maintaining attachment strength.
4Strength
If silicon electrodes are metallurgically bonded to graphite support rings, then strong bonding is achieved, but solder particles or vaporized contaminants cause contamination in sub-65 nanometer processes
Solution Approach 1:
The design accepts that the electrode is a consumable component that will eventually wear or fail. Rather than using permanent metallurgical bonds that create contamination risks, the system uses reversible mechanical attachment methods. When contamination or wear occurs, the electrode is simply replaced rather than repaired, eliminating the need for contamination-prone bonding materials like solder.
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 cam lock clamp system enables quick, clean, and accurate attachment of electrodes, maintaining high process yields by accommodating thermal expansion differences and reducing contamination risks, ensuring uniform plasma density and extended electrode lifespan.
Implementation Method 1
a second end portion (305) including a second diameter larger than a cross-sectional dimension of the body portion and arranged to support one or more disc springs (215) concentrically about the stud
Implementation Method 2
A camshaft (207) with a substantially cylindrical body with a diameter larger than the first diameter. The camshaft is configured to mount within a bore of a backing plate (203) and further comprises an eccentric cutout area located in a central portion of the cylindrical camshaft body
Data Source
AI summary
A cam lock clamp comprises a stud having a substantially cylindrical body with a first end including a head area and a second end arranged to support one or more disc springs concentrically about the stud. A socket is arranged to mechanically couple concentrically around the stud with the head area of the stud being exposed above an uppermost portion of the socket. The socket is configured to be firmly attached to a consumable material. A camshaft has a substantially cylindrical body and is configured to mount within a bore of a backing plate. The camshaft further comprises an eccentric cutout area located in a central portion of the camshaft body. The camshaft is configured to engage and lock the head area of the stud when the consumable material and the backing plate are proximate to one another.