Microplasma Generator for Atmospheric Pressure Thin Film Deposition
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Solution Overview
Problem
Current photovoltaic (PV) device manufacturing technologies, inherited from the semiconductor industry, are not cost-effective for large-area production due to high-vacuum requirements and batch processing methods, which are not suitable for the production of large PV cells.
Innovation Solution
A microplasma generator using an array of metal strips with high-frequency power supply to create a low-temperature, atmospheric-pressure plasma, allowing for continuous plasma generation over extended areas, suitable for roll-to-roll coating of substrates, including inexpensive materials like plastics, and enabling deposition or etching of thin films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-vacuum technology and batch processing are used for PV manufacturing, then manufacturing precision and film quality are improved, but device complexity and production cost increase significantly
Solution Approach 1:
The patent changes the operating pressure parameter from high-vacuum conditions to atmospheric pressure, enabling plasma processing without complex vacuum systems. This is achieved by using a dielectric barrier discharge mechanism that sustains plasma at atmospheric pressure, thereby simplifying the overall system while maintaining film deposition quality
Solution Approach 2:
The patent replaces the mechanical vacuum system with an atmospheric pressure plasma system using dielectric barrier discharge. This substitution eliminates the need for vacuum pumps, chambers, and associated mechanical components, significantly reducing device complexity while maintaining manufacturing precision
2Manufacturing precision
If batch processing is used for PV manufacturing, then manufacturing precision is maintained, but productivity decreases due to sequential chamber transfer
Solution Approach 1:
The patent enables continuous processing by eliminating the need for batch-wise chamber transfers. The atmospheric pressure plasma system allows substrates to be processed continuously in a single reactor, maintaining manufacturing precision while dramatically improving productivity through uninterrupted film deposition
Solution Approach 2:
The patent merges multiple processing functions into a single atmospheric pressure reactor, eliminating the need for separate vacuum chambers and transfer mechanisms. This consolidation maintains film quality while enabling continuous high-volume production
3Ease of manufacture
If low-cost substrate materials like plastics are used, then manufacturing cost decreases, but temperature control becomes critical to prevent substrate damage
Solution Approach 1:
The patent changes the plasma generation mechanism to dielectric barrier discharge at atmospheric pressure, which operates at lower temperatures compared to conventional plasma methods. This parameter change enables the use of low-cost plastic substrates by preventing thermal damage while maintaining deposition quality
4Device complexity
If atmospheric pressure plasma is used instead of vacuum plasma, then device complexity and cost decrease, but plasma generation difficulty increases
Solution Approach 1:
The patent introduces a dielectric barrier as an intermediary element that enables plasma generation at atmospheric pressure. The dielectric barrier modifies the discharge characteristics, allowing stable plasma formation without vacuum conditions, thereby simplifying the system while making plasma generation achievable
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 solution enables cost-effective, high-volume production of PV devices by using low-temperature plasmas at atmospheric pressure, allowing the use of low-cost substrates and eliminating the need for expensive vacuum technology, while providing high-quality thin-film deposition and etching capabilities.
Implementation Method 1
High frequency power is supplied to the strip... A microplasma forms in the gap between the second end of the strip and the grounded electrode due to electric fields in that region
Implementation Method 2
A microplasma forms in the gap between the second end of the strip and the grounded electrode... low-temperature, atmospheric-pressure plasma
Implementation Method 3
The remaining strips resonate due to coupling from the at least one powered strip... the frequency of the power provided to the array is selected to correspond to an excitation frequency of an operating mode of the coupled-array
Implementation Method 4
the surface of the substrate can be altered by the addition of material by using a chemically reactive gas, such as SiH4 (i.e., deposition)... by the removal of material using a suitable reactive gas, such as CF4 (i.e., etching)
Data Source
AI summary
A low-temperature, atmospheric-pressure microplasma generator comprises at least one strip of metal on a dielectric substrate. A first end of the strip is connected to a ground plane and the second end of the strip is adjacent to a grounded electrode, with a gap being defined between the second end of the strip and the grounded electrode. High frequency power is supplied to the strip. The frequency is selected so that the length of the strip is an odd integer multiple of ¼ of the wavelength traveling on the strip. A microplasma forms in the gap between the second end of the strip and the grounded electrode due to electric fields in that region. A microplasma generator array comprises a plurality of strongly-coupled resonant strips in close proximity to one another. At least one of the strips has an input for high-frequency electrical power. The remaining strips resonate due to coupling from the at least one powered strip. The array can provide a continuous line or ring of plasma. The microplasma generator can be used to alter the surface of a substrate, such as by adding material (deposition), removal of material (etching), or modifying surface chemistry.