Ceramic Heater Cylindrical Shaft Terminal Arrangement
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Solution Overview
Problem
The existing ceramic heaters with straight shafts restrict the area for arranging terminals due to a high proportion of the slit on the rear surface of the ceramic plate, limiting the degree of freedom in terminal arrangement for multi-zone heaters.
Innovation Solution
A ceramic heater design featuring a cylindrical shaft with a small and large diameter portion, a long groove extending from the small diameter portion to the outer circumferential portion of the ceramic plate, allowing increased space for terminal arrangement and accommodating a thermocouple guide that can be bent from vertical to horizontal, enhancing the flexibility of terminal placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a straight shaft is used in the ceramic heater, then the structure is simple, but the area proportion of the slit on the rear surface of the ceramic plate becomes high, restricting the area for arranging terminals
Solution Approach 1:
The shaft is divided into two distinct portions: a small diameter portion and a large diameter portion. This segmentation allows the slit to extend into the large diameter portion's extended space, reducing its proportion in the small diameter portion's inside area and increasing the terminal arrangement area.
Solution Approach 2:
The shaft design adds a dimensional element by creating an extended space in the large diameter portion that the slit can utilize. This transforms the two-dimensional slit placement problem into a three-dimensional solution where the slit extends into the extended space, freeing up area on the ceramic plate rear surface for terminal arrangement.
2Ease of manufacture
If the slit extends across the entire rear surface, then the thermocouple guide can be easily positioned, but the degree of freedom for arranging four terminals is restricted
Solution Approach 1:
Different regions of the shaft are assigned different functions: the small diameter portion's inside area is optimized for terminal arrangement, while the large diameter portion's extended space is dedicated to accommodating the thermocouple guide and slit extension. This local differentiation resolves the conflict between ease of manufacture and arrangement flexibility.
3Area of stationary object
If a long groove is provided to extend into the extended area, then the proportion of the groove in the inside area of the small diameter portion is reduced, but the groove geometry becomes more complex
Solution Approach 1:
The groove is segmented into two parts: a first groove portion in the small diameter portion's inside area and a second groove portion extending into the large diameter portion's extended space. This segmentation reduces the groove's proportion in the critical terminal arrangement area while managing the overall groove geometry through structured division.
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 design increases the degree of freedom in arranging terminals and thermocouples, improves thermal uniformity, and reduces the risk of cracks by optimizing the groove and hole geometry, allowing for more efficient temperature measurement and wafer processing.
Implementation Method 1
an inner circumferential side resistance heating element which is embedded in an inner circumferential portion of the ceramic plate; an outer circumferential side resistance heating element which is embedded in an outer circumferential portion of the ceramic plate
Implementation Method 2
measures the temperature on the outer circumferential side of a ceramic plate 420 by an outer circumferential side thermocouple 450
Data Source
AI summary
A ceramic heater includes a ceramic plate in which inner circumferential side and outer circumferential side resistance heating elements are built in; and a cylindrical shaft joined to a rear surface of the ceramic plate. The long hole extends from a start point of the ceramic plate to a terminal position of the outer circumferential portion of the ceramic plate. The entrance portion of the long hole is a long groove. The long groove is provided to extend from the start point to an extended area. Terminals are provided at positions other than the long groove and in a shaft inside area.