Magnetron sputtering sputtering technology "sputter coating"
Sputtering coating is a technique that uses energetic particles to bombard the target surface in a vacuum, so that the bombarded particles are deposited on the substrate.
Generally, a low-pressure inert gas glow discharge is used to generate incident ions. The cathode target is made of coating material, the substrate is used as the anode, and 0.1-10Pa of argon or other inert gas is introduced into the vacuum chamber. The cathode (target) 1-3KV direct current negative high voltage or 13.56MHz radio frequency voltage produces brightness. Light discharge. The ionized argon ions bombard the target surface, causing the target atoms to splash out and deposit on the substrate, forming a thin film.
There are many sputtering methods, mainly two-stage sputtering, three-stage or four-stage sputtering, magnetron sputtering, target sputtering, radio frequency sputtering, bias sputtering, asymmetric AC radio frequency sputtering, ion beam sputtering And reactive sputtering, etc.
Since the sputtered atoms exchange kinetic energy with positive ions with energy of tens of electron volts, the sputtered atoms have high energy, which is beneficial to improve the diffusion ability of the atoms during deposition, and increase the density of the deposited tissue. The produced film has strong adhesion to the substrate.
During sputtering, after the gas is ionized, the gas ions fly to the target material connected to the cathode under the action of the electric field, and the electrons fly to the grounded wall cavity and the substrate. In this way, under low voltage and low pressure, the number of ions generated is small, and the target sputtering efficiency is low; and under high voltage and high pressure, although more ions can be generated, the energy carried by the electrons flying to the substrate is high. , It is easy to cause the substrate to heat up and even cause secondary sputtering, which affects the quality of the film. In addition, the probability of target atoms colliding with gas molecules in the process of flying to the substrate is also greatly increased, so they are scattered to the entire cavity, which will not only waste the target material, but also cause various layers in the preparation of multilayer films. Pollution.