Multilayer Corrosion Coating With Stress Buffer for Metal Substrates
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Solution Overview
Problem
Conventional corrosion-resistant coatings for metal components in semiconductor processing systems fail to adequately protect against highly corrosive halogen-containing environments and large temperature changes, leading to stress fractures and reduced lifespan.
Innovation Solution
A multilayer coating system comprising a bonding layer, a stress buffer layer, and an environmental barrier layer is applied to the metal substrate. The bonding layer is formed by thermal oxidation or ozone exposure, the stress buffer layer is deposited using atomic layer deposition, and the environmental barrier layer is characterized by a low coefficient of thermal expansion, reducing mechanical stress and enhancing adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-layer corrosion-resistant coating is applied to metal substrate, then the coating provides basic corrosion protection, but the coating develops stress fractures under large temperature changes
Solution Approach 1:
The coating system is divided into three distinct layers: a bonding layer containing metal oxides for substrate adhesion, a stress buffer layer with intermediate CTE to absorb thermal expansion stress, and an environmental barrier layer for corrosion protection. This segmentation allows each layer to perform its specific function, resolving the contradiction between corrosion protection and stress resistance.
Solution Approach 2:
The invention uses a composite multilayer coating structure combining materials with different properties: metal oxides in the bonding layer, alumina or other ceramics in the stress buffer layer, and low-CTE materials like silicon oxide in the environmental barrier layer. This composite approach enables simultaneous achievement of adhesion, stress management, and corrosion resistance.
2Reliability
If an environmental barrier layer with low CTE is applied directly on metal substrate, then the coating provides good corrosion resistance, but the large CTE mismatch causes stress fractures
Solution Approach 1:
The stress buffer layer acts as an intermediary between the metal substrate and the low-CTE environmental barrier layer. Its intermediate CTE value gradually transitions the thermal expansion mismatch, preventing direct stress concentration at the interface and eliminating stress fractures while maintaining corrosion resistance.
Solution Approach 2:
The invention changes the CTE parameter distribution across the coating layers by introducing a stress buffer layer with intermediate thermal expansion properties. This gradual parameter transition from high CTE metal substrate to low CTE barrier layer prevents harmful stress concentrations.
3Adaptability or versatility
If the coating layers are made thin to maintain flexibility, then the coating adapts better to temperature changes, but the corrosion barrier becomes penetrable
Solution Approach 1:
The invention transitions from a single thin layer to a multilayer structure with specific thickness ratios. The bonding layer is thin (0-10 nm) for flexibility, the stress buffer layer is moderate (10-100 nm) for stress management, and the environmental barrier layer is thicker (50-500 nm) for corrosion protection. This dimensional distribution across layers resolves the contradiction.
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 multilayer coating significantly increases the corrosion resistance of metal substrates to halogen-containing substances, reduces stress fractures, and extends the operational lifespan of components by maintaining an impenetrable barrier against corrosive gases and plasmas.
Implementation Method 1
the bonding layer is formed on the metal substrate by thermal oxidation of the metal in the metal substrate
Implementation Method 2
the stress buffer layer and the environmental layer are deposited by atomic layer deposition
Data Source
AI summary
Exemplary methods of coating a metal-containing component are described. The methods are developed to increase corrosion resistance and improve coating adhesion to a metal substrate. The methods include forming a bonding layer on a metal substrate, where the bonding layer includes an oxide of a metal in the metal substrate. The coating methods further include depositing a stress buffer layer on the bonding layer, where the stress buffer layer is characterized by a stress buffer layer coefficient of thermal expansion (CTE) that is less than a metal substrate CTE and a bonding layer CTE. The coating methods also include depositing an environmental barrier layer on the stress buffer layer, where a ratio of the metal substrate CTE to an environmental barrier layer CTE is greater than or about 20:1, and where the environmental barrier layer includes silicon oxide. The metal-containing components may be used in fabrication equipment for electronic devices.