What is Magnetron Sputtering?
Magnetron sputtering is a type of physical vapor deposition, a process in which a target material is vaporized and deposited on a substrate to create a thin film. Since it uses magnets to stabilize the charges, magnetron sputtering can be conducted at lower pressures. Additionally, this sputtering process can create accurate and evenly distributed thin films, and it allows for more variety in the target material. Magnetron sputtering is often used to form thin films of metal on different materials, such as plastic bags, compact discs (CDs), and digital video discs (DVDs), and it is also commonly used in the semiconductor industry.
Generally, a traditional sputtering process begins in a vacuum chamber with the target material. Argon, or another inert gas, is slowly brought in, allowing the chamber to maintain its low pressure. Next, a current is introduced through the machine’s power source, bringing electrons into the chamber that begin to bombard the argon atoms and knock off the electrons in their outer electron shells. As a result, the argon atoms form positively charged cations that begin to bombard the target material, releasing small molecules of it in a spray that collects on the substrate.
While this method is generally effective for creating thin films, the free electrons in the chamber are not only bombarding the argon atoms, but also the surface of the target material. This can lead to a large degree of damage to the target material, including uneven surface structure and overheating. Additionally, traditional diode sputtering can take a long time to complete, opening up even more opportunities for electron damage to the target material.
Magnetron sputtering offers higher ionization rates and less electron damage to the target material than traditional sputter deposition techniques. In this process, a magnet is introduced behind the power source to stabilize the free electrons, protect the target material from electron contact, and also increase the likelihood that the electrons will ionize the argon atoms. The magnet creates a field that keeps the electrons restrained and trapped above the target material where they cannot harm it. Since the magnetic field lines are curved, the path of the electrons in the chamber is extended through the stream of argon, improving ionization rates and decreasing the time until the thin film is complete. In this way, magnetron sputtering is able to counteract the initial problems of time and target material damage that had occurred with traditional diode sputtering.
What is the difference between planar and confocal magnetron sputtering?
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