Hollow Ceramic Shaft Gastight Mounting via Metal Ring Mediator
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Solution Overview
Problem
The existing shaft-end mounting structures for semiconductor production apparatuses face issues with maintaining a gastight seal without risking the breakage of hollow ceramic shafts due to overtightening, which can lead to improper sealing.
Innovation Solution
A shaft-end mounting structure utilizing a ring member made of metal or metal-ceramic composite materials, integrated with a hollow ceramic shaft and a base plate via a metal layer and seal, allowing for strong tightening without risking the ceramic shaft's integrity, using a fastening member that extends through the base plate and seal layer to ensure gastight isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bolts are strongly tightened to ensure good sealing properties, then the metal seal provides sufficient sealing, but the hollow ceramic shaft may break
Solution Approach 1:
A ring member made of metal or metal-ceramic composite material is introduced as an intermediary component between the hollow ceramic shaft and the base plate. This ring member has higher strength than ceramic and can withstand strong tightening forces from the fastening member without breaking, while still allowing the metal seal to be compressed sufficiently to provide good sealing properties. The ring member thus mediates between the conflicting requirements of strong sealing and ceramic shaft protection.
Solution Approach 2:
The ring member is composed of metal material or metal-ceramic composite material, which combines the high strength and ductility of metals with the thermal and chemical stability of ceramics. This composite material approach allows the ring member to have sufficient strength to prevent ceramic shaft breakage during tightening while maintaining compatibility with the ceramic shaft and providing effective sealing.
2Strength
If the bolts are insufficiently tightened to avoid breaking the ceramic shaft, then the ceramic shaft remains intact, but the metal seal cannot function properly
Solution Approach 1:
The ring member serves as a mediator that decouples the tightening force from the ceramic shaft. The fastening member strongly tightens the ring member against the base plate, which in turn compresses the metal seal between the ring member and the base plate to ensure proper sealing. The ceramic shaft is not directly involved in this tightening process, so it remains intact while the seal functions properly.
3Reliability
If a ceramic flange is used to maintain gastight seal, then sealing is achieved, but the flange is prone to breakage under tightening stress
Solution Approach 1:
The ring member is made of metal or metal-ceramic composite material, which provides both the strength needed to withstand tightening forces and the compatibility needed for effective sealing. Metal-ceramic composite materials specifically combine the advantages of both metals (strength, ductility) and ceramics (thermal stability, chemical resistance, sealing capability), making them ideal for this application where both mechanical strength and sealing properties are critical.
Solution Approach 2:
The invention changes the material parameter of the flange from ceramic to metal or metal-ceramic composite, fundamentally altering the mechanical properties. This material substitution increases the strength and toughness of the flange while maintaining or improving its sealing capabilities, allowing it to withstand the tightening stresses without breaking.
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
This solution provides a robust and reliable gastight seal, preventing the breakage of the hollow ceramic shaft while ensuring effective sealing properties, even under strong tightening conditions, and minimizes thermal expansion-related issues by using materials with matching coefficients.
Implementation Method 1
a ring member connected in a gastight manner to an end face of the hollow ceramic shaft with a metal layer provided therebetween
Implementation Method 2
the ring member is placed on the circumference of the through hole in the base plate of the chamber with the seal layer provided therebetween
Data Source
AI summary
A shaft-end mounting structure according to the present invention is a structure to mount an end of a hollow ceramic shaft 20 in a gastight manner on a circumference of a through hole 104 in a base plate 102 of a chamber 100, the shaft 20 being integrated with a ceramic plate 12 on which a wafer is to be placed. A ring member 26 is connected in a gastight manner to an end face of the shaft 20 with a metal layer 28 provided therebetween, the member 26 being composed of a metal material or a metal-ceramic composite material. Bolts 32 extend through the base plate 102 and a metal seal 30 and fasten the member 26 so as to draw the member 26 toward the base plate 102 while the member 26 is placed on the circumference of the through hole 104 with the seal 30 provided therebetween.