Silicon-Brazed Ceramic Joints for High-Temperature Hermetic Sealing
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Solution Overview
Problem
Current methods for joining ceramic components in semiconductor processing equipment face challenges such as high manufacturing costs, limited repair options, and inability to withstand high temperatures due to diffusion and corrosion issues, as well as the need for complex and expensive specialized equipment and processes.
Innovation Solution
A method involving brazing with high purity silicon or silicon alloys under controlled atmospheres to create hermetic joints between ceramic pieces, which are resistant to high temperatures and corrosive environments, allowing for potential disassembly and repair of the components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If liquid phase sintering is used to join ceramic components, then strong joints are achieved, but high compressive force and high temperature equipment are required increasing complexity and cost
Solution Approach 1:
A boron-containing intermediate layer is introduced between the ceramic components to facilitate bonding. This intermediate layer enables joint formation at lower temperatures and pressures by providing a eutectic reaction pathway, eliminating the need for complex high-pressure sintering equipment while achieving strong joints.
Solution Approach 2:
The joining process utilizes changes in temperature and pressure parameters to achieve eutectic melting of the boron-containing intermediate layer. By controlling these parameters to reach the eutectic point, strong bonds form at lower overall temperatures and pressures compared to conventional liquid phase sintering, reducing equipment complexity.
2Strength
If thick shaft walls are used to support compressive forces during sintering, then structural integrity is maintained, but heat flow down the shaft increases
Solution Approach 1:
The mechanical support function during joining is replaced by the boron-containing intermediate layer, which provides bonding strength without requiring thick shaft walls for structural support. This allows thin-walled shafts that minimize heat conduction losses while maintaining integrity during the joining process.
3Reliability
If ceramic components are joined using conventional methods, then hermetic seals are achieved, but the joints cannot withstand high temperatures due to diffusion and corrosion
Solution Approach 1:
The boron-containing intermediate layer is designed to remain stable and protective at high temperatures, forming a durable barrier that prevents diffusion and corrosion. This intermediate layer acts as a sacrificial protective element that maintains hermetic seal integrity even at elevated operating temperatures where conventional joints would fail.
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 approach reduces manufacturing costs and complexity by eliminating the need for high-pressure and high-temperature liquid phase sintering, enables the use of ceramic components at higher temperatures, and allows for the repair and reuse of equipment by creating strong, hermetic seals that maintain integrity in harsh processing conditions.
Implementation Method 1
brazing a layer of joining material between the two pieces
Implementation Method 2
heating the silicon binder to a temperature of at least 1414 C in vacuum, and cooling the silicon binder to a temperature below its melting point
Implementation Method 3
heating the silicon binder to a temperature of at least 1414 C in vacuum, and cooling the silicon binder to a temperature below its melting point so that the binder hardens and creates a hermetic seal
Implementation Method 4
The ceramic heater may be used for substrate processing in a process chamber
Data Source
AI summary
A method for the joining of ceramic pieces with a hermetically sealed joint comprising brazing a layer of joining material between the two pieces. The ceramic pieces may be aluminum nitride or other ceramics, and the pieces may be brazed with a high purity silicon or a silicon alloy under controlled atmosphere. The joint material is adapted to later withstand both the environments within a process chamber during substrate processing, and the oxygenated atmosphere which may be seen within the interior of a heater or electrostatic chuck.