Electronic products are used in all walks of life. Most of these electronic products need to be coated before they are put into the market. Now the commonly used vacuum coating equipment is magnetron sputtering vacuum coating machine. And usually the targets used in the sputtering are mainly three types: metal targets, alloy targets and compound targets.
There are many target materials for HDDs. A multilayer film is applied to the recording surface and each film has its own function. At the bottom layer, a 40-nm-thick chromium or chromium alloy film is applied to enhance the good adhesion and great corrosion resistance. And a 15nm-thick cobalt-chromium alloy film is then plated in the middle and a 35nm-thick cobalt alloy film is coated as a magnetic material which can fully exhibit magnetic properties and low-interference characteristics. Finally, a 15nm-thick carbon film is coated.
The sputtering target for the magnetic head is usually an iron-nickel alloy, and later, some new compound materials, such as iron nitride, antimony nitride, aluminum nitride, etc., have been adopted. These are all excellent magnetic dielectric film targets.
CD discs will be coated with aluminum film as a reflective layer on the plastic workpiece, but for CDROM and DVDROM, aluminum film cannot work, because there will be a dye layer on these discs, the above material has a certain degree of corrosiveness for aluminum, and it is generally replaced by a gold film or a silver film.
The coating of the optical disc is also composed of multiple layers. The 30-nm-thick iron-cobalt alloy recording layer coated on the dye layer contains some amorphous rare-earth transition element, and then a 20 to 100-nm-thick silicon nitride dielectric layer is coated on it. Finally, an aluminum reflective layer is coated.
These electronic products require magnetic performance to record data, and it is achieved by sputtering the coating with a variety of different materials.