Ceramic Plate to Metal Pipe Brazing Structure for Thermal Stress
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Solution Overview
Problem
The existing structure for joining a ceramic plate to a metal cylindrical member in electrostatic chucks is prone to separation and cracking due to thermal expansion differences, leading to air tightness issues and leakage during thermal cycles.
Innovation Solution
A structure featuring a flange with a width of 3 mm or more and a thickness of 0.5 to 2 mm, with an annular bank having a chamfered or rounded edge, which increases the joining area and stress resistance, and using a brazing filler material like Ag-Cu-Ti or Al to reduce thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a metal gas introduction pipe is joined to a ceramic plate using brazing, then thermal conductivity is improved, but the joint portion may separate due to thermal expansion differences during heat cycles
Solution Approach 1:
The gas introduction pipe is divided into two separate portions: a first gas introduction pipe joined to the rear surface of the ceramic plate, and a second gas introduction pipe joined to the front surface. This segmentation allows each pipe to be optimized independently for thermal conductivity and stress resistance, preventing joint separation during thermal cycles while maintaining improved thermal conductivity.
2Stress or pressure
If the gas introduction pipe is formed of metal with thermal expansion coefficient close to ceramic plate, then stress is reduced, but joint portion still cracks after repeated thermal cycles
Solution Approach 1:
Dividing the gas introduction pipe into two portions joined at different locations on the ceramic plate distributes thermal stress more evenly, preventing concentration of stress at a single joint and thereby improving crack resistance after repeated thermal cycles.
Solution Approach 2:
A brazed joint is introduced as an intermediary element between the metal gas introduction pipe and the ceramic plate. This brazed joint acts as a stress-absorbing interface that accommodates thermal expansion differences, preventing direct stress transmission that would cause cracking.
3Ease of manufacture
If brazing filler material is applied from side surface of gas introduction pipe to rear surface of electrostatic chuck, then joining is achieved, but stress concentration occurs leading to separation
Solution Approach 1:
The brazing operation is segmented into two separate locations: one brazed joint on the rear surface and another on the front surface. This segmentation prevents stress concentration at a single brazed location, improving joint durability while maintaining ease of manufacture through standardized brazing procedures at each location.
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 enhances durability against thermal cycles by distributing stress and maintaining air tightness, preventing cracking and leakage even after repeated thermal exposure.
Implementation Method 1
a brazing method is known. In this method, brazing is performed by filling a brazing filler material in a space between a ceramic plate 110 and a gas introduction pipe 120
Implementation Method 2
stress is produced between the ceramic plate 110 and the gas introduction pipe 120 due to the difference in thermal expansion between the ceramic plate 110 and the gas introduction pipe 120
Data Source
AI summary
A member for semiconductor manufacturing device includes a susceptor which is a ceramic plate formed of AlN and a gas introduction pipe which is joined to the susceptor. An annular pipe joining bank is provided at a position of the susceptor facing a flange of the gas introduction pipe. In addition, a pipe brazed part is formed between the flange and the pipe joining bank. The flange has a width of 3 mm or more and a thickness of from 0.5 to 2 mm. It is preferable that the height of the pipe joining bank be 0.5 mm or more, the edge of the bank facing the outer edge of the flange. be chamfered as designated by C0.3 or more or rounded as designated by R0.3 or more.