In the previous article, we talked about the characteristics of sputtering coatings, and this article will continue to explain the characteristics of sputtering coatings.
(4) The substrate temperature is low. The sputtering rate of sputtering is high because the concentration of electrons is high within the magnetic field region of the cathode target, that is, in a small local area on the target discharge runway, and outside the magnetic action region, especially near the substrate surface far from the magnetic field, the electron concentration is much lower due to divergence, and may even be lower than that of binary sputtering (because the operating gas pressure of the two is an order of magnitude different). Therefore, under sputtering conditions, the electron concentration on the surface of the bombarded substrate is much lower than that in ordinary secondary sputtering, and the excessive increase in the substrate temperature is avoided due to the decrease in the number of electrons in the incident substrate. In addition, in the sputtering method, the anode of the sputtering device can be located around the cathode, and the substrate frame can also be and at a suspended potential, so that electrons can flow away through the anode without passing through the grounded substrate frame, thereby reducing the high-energy electrons that bombard the plated substrate, reducing the increase in substrate heat caused by electron incidence, and greatly reducing the heat caused by secondary electron bombardment of the substrate.
(5) Uneven etching of the target. In the traditional sputtering target, an inhomogeneous magnetic field is used, so the plasma will produce a local convergence effect, which will make the sputtering etching rate of the local position on the target extremely large, and the result will be significant uneven etching on the target. The utilization rate of target materials is generally about 30%. In order to improve the utilization rate of the target material, various improvement measures can be taken, such as improving the shape and distribution of the target magnetic field, so that the magnet moves inside the target cathode
(6) Magnetic material target sputtering is difficult. If the sputtering target is made of a material with high magnetic permeability, magnetic field lines will pass directly and so on. A magnetic short circuit occurs inside the target, making discharge difficult. In order to generate a spatial magnetic field, various studies have been carried out, for example, saturating the magnetic field inside the target, leaving many gaps on the target to promote it to generate more leakage magnetism to increase the temperature of the target, or reduce the magnetic permeability of the target.
– This article is released by vacuum coating machine manufacturer Guangdong Zhenhua
Post time: Sep-08-2023