MgO-AlN Solid Solution Electrostatic Chuck Corrosion Resistance
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Solution Overview
Problem
Conventional electrostatic chucks used in semiconductor production, made of materials like alumina and aluminum nitride, suffer from corrosion when exposed to halogen-based gases, leading to deteriorated temperature uniformity and adsorption force over time.
Innovation Solution
A ceramic material with a MgO—AlN solid solution is used as the main phase, providing superior corrosion resistance and maintaining temperature uniformity and adsorption force by forming a surface corrosion-resistant layer on the susceptor, which includes magnesium, aluminum, oxygen, and nitrogen components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alumina or aluminum nitride is used as the ceramic material for the electrostatic chuck, then good initial temperature uniformity is achieved, but corrosion occurs when exposed to halogen-based gases, leading to deteriorated temperature uniformity and adsorption force over time
Solution Approach 1:
The patent employs a composite ceramic material consisting of magnesia (MgO) as the base material with alumina (Al2O3) and aluminum nitride (AlN) as additive components. This composite structure combines the high corrosion resistance of magnesia with the thermal conductivity benefits of alumina and aluminum nitride, creating a material that maintains both temperature uniformity and corrosion resistance over extended service periods in halogen-based gas environments
Solution Approach 2:
The patent modifies the chemical composition parameters of the ceramic material by incorporating specific ratios of MgO, Al2O3, and AlN. This parameter change transforms the material properties to achieve optimal balance between corrosion resistance and thermal performance, preventing the degradation that occurs with pure alumina or aluminum nitride under corrosive conditions
2Temperature
If alumina or aluminum nitride is used as the ceramic material, then good initial temperature uniformity is obtained, but the shape and roughness of the heater surface changes due to corrosion, causing temperature distribution to change over time
Solution Approach 1:
The magnesia-based composite ceramic material provides superior surface stability under corrosive conditions. The magnesia matrix with alumina and aluminum nitride additives creates a chemically stable surface that resists shape changes and roughness degradation, thereby maintaining consistent temperature distribution across the heater surface throughout the service life of the electrostatic chuck
Solution Approach 2:
The patent employs magnesia as the base material which, while having lower intrinsic thermal conductivity than pure aluminum nitride, provides superior overall stability and corrosion resistance. This material selection prioritizes long-term performance stability over initial peak performance, ensuring the heater surface maintains its shape and temperature distribution characteristics throughout extended operation
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 ceramic material with a MgO—AlN solid solution effectively resists corrosion and maintains temperature uniformity and adsorption force even under long-term exposure to halogen-based gases, improving the durability and performance of electrostatic chucks in semiconductor processing.
Implementation Method 1
the ceramic material comprises, as a main phase, a crystal phase comprising MgO—AlN solid solution wherein aluminum nitride is dissolved into magnesium oxide
Data Source
AI summary
Each of electrostatic chucks 1A to 1F includes a susceptor 11A having an adsorption face 11a of adsorbing a semiconductor, and an electrostatic chuck electrode 4 embedded in the susceptor. The susceptor includes a plate shaped main body 3 and a surface corrosion resistant layer 2 including the adsorption face 2. The surface corrosion resistant layer 2 is made of a ceramic material comprising magnesium, aluminum, oxygen and nitrogen as main components. The ceramic material comprises a main phase comprising MgO—AlN solid solution wherein aluminum nitride is dissolved into magnesium oxide.