Substrate Holding Board With Multilayer DLC for Low Reflectivity
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Solution Overview
Problem
Existing substrate holding boards in exposure devices suffer from increased reflectivity and charge accumulation, leading to issues such as exposure of unintended regions and potential damage to substrates due to discharge, with existing coatings like DLC facing peeling and oxidation problems.
Innovation Solution
A substrate holding board design featuring multiple layers of diamond-like carbon (DLC) with varying refractive indices and hydrogen contents, along with a silicon carbide layer, to enhance peel resistance, reduce reflectivity, and prevent oxidation, while maintaining effective substrate support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a substrate holding board is coated with a diamond-like carbon (DLC) film and the surface of the DLC film is coated with inorganic system coating agent, then the reflectivity on the surface of the substrate holding board is reduced, but the inorganic transparent thin film is easily peeled off due to insufficient adhesiveness
Solution Approach 1:
The coating is divided into multiple layers: a base DLC layer and an intermediate DLC layer with different hydrogen content. This segmentation allows each layer to have optimized properties - the base layer provides strong adhesion to the substrate holding board, while the intermediate layer provides low reflectivity and good adhesion to the inorganic top coating, resolving the contradiction between peel resistance and reflectivity reduction.
Solution Approach 2:
The invention changes the hydrogen content parameter of the DLC film to create different layers. The base DLC layer has lower hydrogen content (10-50 at%) for strong adhesion, while the intermediate DLC layer has higher hydrogen content (5-30 at%) for low reflectivity and good adhesion to inorganic coatings. This parameter variation resolves the contradiction between adhesion strength and reflectivity reduction.
2Reliability
If a conductive DLC coating doped with nitrogen is provided on a component supporting a substrate, then charge accumulation is reduced, but the DLC film may be oxidized when exposed to ultraviolet light
Solution Approach 1:
The invention applies a protective inorganic coating (such as SiO2, SiN, or SiON) as the topmost layer before the substrate is exposed to ultraviolet light. This preliminary protective layer prevents oxidation of the underlying DLC film while allowing the nitrogen-doped DLC layer beneath to maintain its charge dissipation function, thus resolving the contradiction between charge discharge capability and oxidation resistance.
Solution Approach 2:
The invention creates a composite coating structure combining organic DLC layers with inorganic protective layers. The nitrogen-doped DLC layer provides charge dissipation properties, while the overlying inorganic layer provides oxidation resistance against ultraviolet exposure. This composite structure resolves the contradiction between electrical conductivity and chemical stability.
3Productivity
If the substrate holding board is used repeatedly over the years, then productivity is maintained, but the surface of the substrate holding board becomes worn and reflectivity increases
Solution Approach 1:
The invention applies a multi-layer coating structure before the substrate holding board is put into repeated use. The base DLC layer provides wear resistance to protect against surface degradation during repeated operations, while the intermediate and top layers maintain low reflectivity. This beforehand protection prevents the increase in reflectivity that normally occurs with repeated use, allowing continuous productivity without performance degradation.
Solution Approach 2:
The multi-layer composite coating combines wear-resistant DLC material with low-reflectivity intermediate layers. This composite structure provides both the durability needed for repeated operations and the optical properties needed to maintain low reflectivity, resolving the contradiction between continuous operation capability and reflectivity control.
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 multi-layered DLC and silicon carbide coating significantly reduces reflectivity and prevents oxidation, enhancing substrate protection and ensuring uniform exposure results by minimizing charge accumulation and substrate damage.
Implementation Method 1
a refractive index of the first layer in a wavelength is higher than a refractive index of the second layer in the wavelength
Implementation Method 2
the DLC film may be oxidized when the surface of the substrate holding board is exposed to light such as ultraviolet light
Data Source
AI summary
A substrate holding board includes a first layer and a second layer forming an interfacial surface with the first layer. The first layer and the second layer contain diamond-like carbon. A refractive index of the first layer in a wavelength is higher than a refractive index of the second layer in the wavelength. A distance from the second layer to a topmost surface of the substrate holding board is smaller than a thickness of the first layer.