RF-Plasma Glow Discharge Sputtering for High Ionization
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Solution Overview
Problem
Conventional glow discharge sputtering apparatuses have limited effectiveness for substrate etching and coating deposition due to low ionization degree of sputtered species, leading to poor etching and adhesion, and low coating density, especially when dealing with complex substrate profiles.
Innovation Solution
An RF-plasma glow discharge apparatus and method that generates a high-density plasma using an RF antenna with a peak power density greater than 50 W/cm², achieving high target currents and ionization of sputtered species by pulsing power at both the RF antenna and cathodic target, with optimized impedance matching and synchronization of power pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional glow discharge sputtering is used, then the process is simple and equipment is less complex, but the ionization degree of sputtered species is low leading to poor etching and adhesion
Solution Approach 1:
The patent combines RF plasma generation with glow discharge sputtering in a single apparatus. The RF antenna generates plasma that enhances ionization of sputtered species, while the cathodic target maintains sputtering function. This merging of plasma generation and sputtering processes resolves the contradiction by achieving high ionization degree without requiring separate complex equipment.
Solution Approach 2:
The patent applies RF power with peak power density greater than 50 W/cm² to the plasma generation process, significantly changing the energy parameter compared to conventional glow discharge. This parameter change increases the ionization degree of sputtered species, improving etching quality and coating adhesion while maintaining apparatus feasibility.
2Manufacturing precision
If magnetic field is used in plasma region, then plasma confinement is improved, but charged particles cannot be accelerated directly along electric field causing non-conformal ion implantation
Solution Approach 1:
The patent extracts the magnetic field from the plasma region, eliminating its confining effect. By removing the magnetic field component, charged particles can be accelerated directly along the electric field lines, achieving conformal ion implantation and deposition. The RF plasma provides sufficient confinement through electromagnetic induction without magnetic field interference.
3Quantity of substance
If high power density RF antenna is used, then plasma density and ionization efficiency are enhanced, but target surface charging and arcing may increase
Solution Approach 1:
The patent employs pulsed RF power delivery to the antenna rather than continuous power. This periodic action allows the plasma to be regenerated and refreshed during each pulse cycle, preventing excessive target surface charging that would lead to arcing. The pulse timing is optimized to maintain high plasma density while avoiding harmful charging effects.
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 enhances etching speed, coating adhesion, and uniformity, allowing for effective deposition on substrates with complex profiles without magnetic field containment, and minimizes target surface charging and arcing.
Implementation Method 1
RF-plasma glow discharge sputtering using an RF antenna to generate a plasma of ion species in which the peak power density at the RF antenna is greater than 50 Wcm -2
Implementation Method 2
Metallic plasma sources are indispensable in the preparation of high-quality films, as they work in a manner that supplies highly-purified and uniformly distributed metallic species to a given region with high density
Implementation Method 3
When a magnetic field is used in the plasma region, charged particles may not be accelerated directly along the electric field. This causes not only random ionic motion, but also a non-conformal ion implantation and deposition
Data Source
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AI summary
RF-plasma glow discharge apparatus and method for pulsed sputtering plasma. The apparatus and method comprise means to pulse the power at a sputter target and an RF antenna so as to create a peak power density at the RF antenna of greater than 50 Wcm -2. A plasma of highly ionised sputtered species is generated with or without a magnetic field. Sputter species include metallic, non-magnetic, ceramic and oxide materials that may be used for substrate etching and deposition. Consideration is also given to plasma and target power supply impedance so as to optimise the intensity of generated plasma species. Synchronisation of the power pulses at the target and RF antenna is also disclosed.