Unbalanced Magnetron Sputtering Source for Higher Plasma Ionization
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Solution Overview
Problem
Current ionized physical vapor deposition (I-PVD) sputtering technologies face limitations in achieving high-density plasma and efficient sputtering processes, particularly in generating unbalanced magnetron configurations and managing plasma ionization and deposition rates.
Innovation Solution
The implementation of an electrically and magnetically enhanced I-PVD unbalanced magnetron sputtering apparatus, which includes a cathode target assembly, an additional electrode assembly, and a power supply system generating unbalanced magnetic fields and RF power to enhance plasma ionization and deposition, utilizing a tunable pulse forming network (PFN) to produce high-power pulse resonance asymmetric AC waveforms for improved sputtering efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional I-PVD sputtering is used, then the process can deposit material on substrates, but plasma density and ionization efficiency remain insufficient
Solution Approach 1:
The patent combines a magnetron sputtering source with an inductively coupled plasma (ICP) source in a single apparatus. The magnetron component generates initial plasma and sputters target material, while the ICP coil enhances plasma density through inductive coupling. This merging of two plasma generation mechanisms resolves the contradiction by achieving both high plasma density and efficient deposition simultaneously.
Solution Approach 2:
The apparatus is designed to perform multiple functions: the magnetron sputtering source deposits material while the ICP source enhances plasma ionization. The system can operate in different modes (magnetron-only, ICP-only, or combined) to achieve various deposition rates and plasma densities, providing universal functionality that resolves the trade-off between plasma density and productivity.
2Quantity of substance
If magnetic field lines are balanced in conventional magnetron sputtering, then the magnetron configuration is stable, but ionization efficiency and plasma density are limited
Solution Approach 1:
The patent introduces an unbalanced magnetron configuration where magnetic field lines are deliberately asymmetric rather than symmetric. This asymmetry enhances plasma confinement and increases ionization efficiency by creating regions of higher electron density and longer electron residence time, while the overall magnetic field structure remains stable through proper design of the magnet assembly.
3Quantity of substance
If additional ICP coil is added to enhance plasma ionization, then ionization increases, but device complexity increases
Solution Approach 1:
The ICP coil is designed to serve multiple functions: enhancing plasma ionization, increasing plasma density, and enabling control over plasma chemistry. By integrating this single component to perform multiple functions, the patent reduces the need for additional separate systems, thereby limiting the increase in device complexity while achieving enhanced gas ionization.
4Productivity
If high power is applied to increase deposition rate, then productivity improves, but plasma parameter control becomes more difficult
Solution Approach 1:
The patent incorporates control systems that monitor plasma parameters (such as plasma impedance, power absorption, and deposition rate) and provide feedback to adjust operating conditions. This feedback mechanism enables precise control of plasma parameters even at high power levels, resolving the contradiction between high productivity and precise parameter 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
This approach enables the generation of high-energy density plasma, enhancing deposition rates and ion bombardment on substrates, with improved control over plasma parameters and increased efficiency in forming layers on substrates.
Implementation Method 1
Magnetic field geometry of the electrically and magnetically enhanced unbalanced magnetron sputtering source has an unbalanced magnetron configuration on a cathode target surface. Magnetic field lines that form a magnetron configuration on the cathode target surface are unbalanced from the center.
Implementation Method 2
The additional electrode is connected to a power supply that can generate a positive, negative, or high frequency bipolar voltage with a frequency in the range of 100 KHz to 100 MHz. In some embodiments, the additional electrode is connected to the power supply that generates an RF voltage.
Implementation Method 3
An ionized physical vapor deposition (I-PVD) sputtering and resputtering process can be performed in the same process module
Implementation Method 4
The RF power supply can generate voltage oscillations with a frequency are in the range of 100 kHz to 100 MHz. The RF power supply provides a power selected to increase ionization of sputtered target material atoms associated with the cathode target during sputtering.
Implementation Method 5
The cathode target can be connected with an RF power supply. The RF power supply can generate voltage oscillations with a frequency are in the range of 100 kHz to 100 MHz. The cathode target can be grounded through an inductor to eliminate negative voltage bias generated by RF discharge.
Data Source
AI summary
A method of depositing a layer on a substrate includes applying a first magnetic field to a cathode target, electrically coupling the cathode target to a first high power pulse resonance alternating current (AC) power supply, positioning an additional cylindrical cathode target electrode around the cathode, applying a second magnetic field to the additional cylindrical cathode target electrode, electrically coupling the additional cylindrical cathode target electrode to a second high power pulse resonance AC power supply, generating magnetic coupling between the cathode target and an anode, providing a feed gas, and selecting a time shift between negative voltage peaks associated with AC voltage waveforms generated by the first high power pulse resonance AC power supply and the second high power pulse resonance AC power supply. An apparatus includes a vacuum chamber, cathode target magnet assembly, first high power pulse resonance AC power supply, additional electrode, additional electrode magnet assembly, second high power pulse resonance AC power supply, and feed gas.