Compact Cold Cathode Vacuum Gauge for Thin-Film Deposition
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Solution Overview
Problem
Current vacuum gauges in thin-film deposition lines are bulky, inaccurate, costly to maintain, and unable to provide precise vacuum measurements near the substrate due to space and magnetic field constraints, leading to production delays and quality issues.
Innovation Solution
A compact cold cathode ionization pressure gauge with a double plasma design, integrated into an on-board system, allows for accurate vacuum level measurement close to the substrate, reducing the need for multiple gauges and minimizing maintenance disruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional vacuum gauges are used in thin-film deposition lines, then vacuum measurement is possible, but the gauges are bulky and cannot be positioned close to the substrate due to space constraints
Solution Approach 1:
The vacuum gauge is divided into separate functional components: a flat cathode mounted on the substrate, a flat anode positioned above it, and magnets arranged in pairs. This segmentation allows each component to be small and flat, enabling placement in the limited space between the substrate and deposition chamber while maintaining measurement functionality.
Solution Approach 2:
The invention transitions from traditional three-dimensional vacuum gauges to a two-dimensional flat configuration. The cathode, anode, and magnets are all arranged in flat planes with small separations, allowing the gauge to fit within the constrained vertical space of the deposition chamber while providing accurate vacuum measurements near the substrate surface.
2Measurement precision
If traditional vacuum gauges are used, then vacuum measurement is possible, but they are inaccurate due to drift over time and pollution from deposited material
Solution Approach 1:
The measurement components (cathode, anode, magnets) are extracted from the main deposition chamber environment and mounted on the substrate itself. This extraction places the sensitive measurement elements away from the direct path of deposited material, reducing pollution and drift while maintaining accurate vacuum measurements during the deposition process.
Solution Approach 2:
The substrate serves a dual function: as the object being coated and as the mounting platform for the vacuum gauge. This self-service arrangement integrates the measurement system with the processing object, allowing continuous monitoring without additional external components that would be susceptible to pollution from the deposition process.
3Measurement precision
If multiple vacuum gauges are distributed along the deposition line, then comprehensive vacuum monitoring is possible, but the cost and maintenance complexity increase significantly
Solution Approach 1:
The substrate-mounted vacuum gauge serves multiple functions: it monitors vacuum conditions at the substrate location, travels with the substrate through different chambers, and provides measurement data for multiple deposition processes. This multi-functionality replaces the need for multiple stationary gauges distributed along the deposition line, reducing overall system complexity and maintenance requirements.
Solution Approach 2:
The vacuum measurement system transitions from static stationary gauges to a dynamic configuration where the gauge moves with the substrate through the deposition line. This dynamic arrangement allows a single gauge to monitor vacuum conditions across multiple chambers and processes, providing comprehensive coverage without requiring multiple fixed measurement points.
4Measurement precision
If vacuum gauges are placed close to the substrate, then precise local vacuum measurement is possible, but strong magnetic fields from deposition magnets interfere with the gauge operation
Solution Approach 1:
The gauge components are designed with specific local properties: the cathode and anode are made of non-magnetic materials, and the magnets are arranged in pairs with opposite polarities facing each other. This local configuration creates a controlled magnetic field environment that minimizes interference from the deposition chamber magnets while enabling the cold cathode ionization measurement process to function accurately close to the substrate.
Solution Approach 2:
The magnetic field configuration uses asymmetric arrangement of magnet pairs with opposite polarities, creating a localized field pattern that is optimized for the measurement function while reducing sensitivity to external magnetic field variations from the deposition process. This asymmetric design allows the gauge to operate reliably in the presence of strong external magnetic fields.
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 compact gauge provides precise vacuum measurements along the deposition line, reducing costs and maintenance efforts while ensuring high-quality thin-film production by detecting leaks and anomalies in real-time.
Implementation Method 1
a first cold cathode ionization plasma is generated in a first cathode chamber of the pressure gauge between a first cathode and a first anode in the presence of a first magnetic field
Implementation Method 2
at least one pair of magnets arranged in pairs, the signs of the poles of which are such that in two neighboring plasmas, the magnetic fields are parallel, of the same intensity and of opposite direction
Implementation Method 3
Then the plasma ions are accelerated towards the cathodes and pulverize the atoms of the layer of material present on their surface. These atoms are then deposited on the substrate.
Data Source
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AI summary
A compact device for measuring a secondary vacuum pressure and an on-board system comprising such a device are described. The device and the system are particularly suitable for measuring the vacuum pressure in the compartments of lines for depositing a stack of thin layers on flat substrates. A method for diagnosing the vacuum in a line for depositing thin layers, in which line an on-board system for vacuum monitoring is used, is also described.