Encapsulated Graphite Heater for Semiconductor Processing
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Solution Overview
Problem
Conventional graphite heaters used in semiconductor wafer processing are prone to corrosion, particle generation, mechanical fragility, and dimensional changes, leading to electrical short circuits and non-uniform power density due to their discontinuous surface and serpentine geometry.
Innovation Solution
A method involving a solid graphite body coated with a continuous layer of nitride, carbide, carbonitride, or oxynitride to enhance structural integrity and corrosion resistance, combined with patterned machining to create a stable and robust resistive heater with improved mechanical strength and thermal uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If graphite is machined into a serpentine configuration to create heating zones, then heating functionality is achieved, but mechanical strength and structural integrity deteriorate
Solution Approach 1:
The heating element is segmented into multiple serpentine zones within the graphite body, allowing independent heating control while maintaining the overall structural integrity of the encapsulated graphite component
Solution Approach 2:
The serpentine heating channels are nested within the solid graphite body, with the heating pathways embedded inside the encapsulated structure rather than forming the external shape, preserving mechanical strength
2Temperature
If graphite heater is used for high temperature processing, then temperature resistance is achieved, but corrosion by processing chemicals occurs
Solution Approach 1:
The heater combines graphite material with high temperature resistance and chemically deposited ceramic coating layers for corrosion resistance, creating a composite structure that leverages the strengths of both materials
Solution Approach 2:
A chemically deposited ceramic coating layer acts as an intermediary barrier between the graphite heater and the corrosive semiconductor processing chemicals, protecting the graphite from direct chemical exposure
3Object-affected harmful factors
If conventional coating methods are used on graphite heaters, then corrosion protection is improved, but manufacturing complexity increases
Solution Approach 1:
The graphite heater serves as its own substrate for the chemical deposition process, utilizing its surface properties and thermal characteristics to enable direct in-situ coating formation without requiring separate manufacturing steps
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 solution results in a more stable and mechanically robust graphite heater with enhanced corrosion resistance and uniform heating, reducing the risk of electrical short circuits and maintaining thermal integrity over time.
Implementation Method 1
a semiconductor wafer is processed in an enclosure defining a reaction chamber at a relatively high temperature above 1000°C, with the wafer being placed adjacent to or in contact with a resistive heater coupled to a power source
Implementation Method 2
a disc-shaped graphite body is coated at least on one side thereof with a first coating layer by CVD or similar methods
Data Source
Figure 1a~3b
Figure 4A~6B
AI summary
A graphite heater and method of forming a graphite heater comprising a graphite body configured to form an electrical heating circuit for at least one heating zone through the graphite encapsulated in a continuous overcoat layer comprising at least one of a nitride, carbide, carbonitride or oxynitride of elements selected from a group consisting of B, Al, Si, Ga, refractory hard metals, transition metals, and rear earth metals, or complexes and/or combinations thereof, wherein prior to being configured to form the electrical heating circuit path, the graphite body is coated with a layer comprising at least one of a nitride, carbide, carbonitride or oxynitride of elements selected from a group consisting of B, Al, Si, Ga, refractory hard metals, transition metals, and rare earth metals, or complexes and/or combinations thereof.