Parallel Substrate DLC Coating With Short-Pulse Plasma Control
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Solution Overview
Problem
The existing methods for mass-producing DLC films on multiple plate-shaped substrates without counter electrodes face challenges in achieving the required hardness and friction properties due to broad sheath widths and insufficient internal pressures, leading to the production of amorphous carbon films rather than DLC films.
Innovation Solution
A method involving the use of a DC pulse source with a pulse half width of 0.1 to 3 μsec and internal pressures between 0.1 to 10 Pa to generate plasma, allowing for a narrow sheath width and preventing sheath overlap, thereby producing DLC films with high hardness and low surface roughness on multiple substrates using a downsized apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the internal pressure of the chamber is set to several tens of pascals to narrow the sheath width, then the interval between substrates can be reduced and apparatus size can be downsized, but the produced film lacks sufficient hardness and friction resistance, resulting in amorphous carbon film instead of DLC film
Solution Approach 1:
The patent applies parameter changes by precisely controlling the internal pressure of the chamber within the range of 0.1 to 10 Pa and the pulse half width within 0.1 to 3 μsec. This optimization of physical parameters enables the formation of DLC films with appropriate hardness while maintaining a compact apparatus design with reduced substrate intervals.
2Volume of moving object
If the pulse half width is shortened to narrow the sheath width, then the interval between substrates can be reduced and apparatus can be downsized, but the internal pressure becomes insufficient to produce DLC film with proper characteristics
Solution Approach 1:
The patent employs parameter changes by optimizing both the pulse half width (0.1 to 3 μsec) and internal pressure (0.1 to 10 Pa) simultaneously. This coordinated adjustment of multiple parameters ensures that the sheath width is sufficiently narrow for apparatus downsizing while the internal pressure remains adequate for producing high-quality DLC films with proper hardness and friction resistance.
3Reliability
If a negative voltage is applied for a longer duration to ensure proper film formation, then the film characteristics improve, but the sheath width broadens requiring larger substrate intervals and increasing apparatus size
Solution Approach 1:
The patent applies periodic action by using DC pulse voltage with a short pulse half width of 0.1 to 3 μsec. This pulsed voltage application method generates plasma that forms DLC films with good characteristics while maintaining a narrow sheath width, thereby enabling compact apparatus design with reduced substrate intervals.
4Strength
If the internal pressure is increased to produce DLC film with sufficient hardness, then the film quality improves, but the sheath width increases requiring larger substrate intervals and increasing apparatus size
Solution Approach 1:
The patent resolves this contradiction through parameter changes by setting the internal pressure to an optimized range of 0.1 to 10 Pa. This precise pressure control, combined with a short pulse half width of 0.1 to 3 μsec, produces DLC films with sufficient hardness while maintaining a narrow sheath width that allows for compact apparatus design.
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 enables the production of DLC films with high hardness and low surface roughness on multiple substrates, preventing overheating and allowing film formation on materials with low melting points, while maintaining a compact apparatus design.
Implementation Method 1
applying a negative DC pulse voltage having a pulse half width of 0.1 to 3 μsec to each of the plate-shaped substrates to generate plasma
Implementation Method 2
DLC films are produced on a substrate by disposing a placement electrode on which the substrate is placed and a counter electrode facing the substrate in a chamber such that they have a certain interval and by applying a negative pulse voltage to the counter electrode in a carbon source gas atmosphere to generate plasma
Implementation Method 3
injecting a carbon source gas into the chamber such that an internal pressure of the chamber reaches 0.1 to 10 Pa
Data Source
AI summary
A DLC film mass-producing apparatus 10 includes a chamber 12 connected to ground. In the chamber 12, a plurality of plate-shaped substrates 60 are disposed in parallel at regular intervals, without disposing a counter electrode that faces each of the plate-shaped substrates 60. Sputtering cleaning is then conducted by plasma discharge and an underlying contact layer is formed on each of the plate-shaped substrates 60. Subsequently, a DLC film is produced on each of the plate-shaped substrates 60 by injecting a carbon source gas into the chamber 12 such that the internal pressure of the chamber 12 reaches 0.1 to 10 Pa and applying a negative DC pulse voltage having a pulse half width of 0.1 to 3 μsec to each of the plate-shaped substrates 60 to generate plasma.