The Planar Magnetron is a timeless diode mode sputtering cathode with the vital addition of an irreversible magnet selection behind the cathode. This magnet variety is prepared so that the electromagnetic field on the face of the target is normal to the electrical area in a shut path and also forms a limit tunnel which catches electrons near the surface of the target. This enhances the effectiveness of gas ionization and also constrains the discharge plasma, enabling greater existing at reduced gas stress as well as attains a higher sputter deposition price for CVD coverings. Numerous different Magnetron cathode/target forms have been utilized, but the most usual are circular as well as rectangular. Rectangle-shaped Magnetrons are usually found in bigger scale in line systems where substrates scan linearly past the targets on some form of conveyor belt or provider. Round Magnetrons are a lot more typically located in smaller range co focal batch systems or solitary wafer stations in collection tools.
Although more facility patterns can be done, a lot of cathodes – including virtually all circular as well as rectangular ones – have a simple concentric magnet pattern with the center being one pole and the border the opposite. For the circular Magnetron, this would be a relatively little round magnet in the center, and an annular ring magnet of the opposite polarity around the outdoors with a gap in between. For the rectangle-shaped Magnetron the facility one is normally a bar down the lengthy axis yet much less than the complete size with a rectangular fence of the opposite polarity completely around it with a space in between. The space is where the plasma will be, a circular ring in the circular Magnetron or an elongated race track in the rectangular. Keep in mind that, particularly in bigger cathodes, the magnets can be numerous specific segments rather than one strong item.
As it is used in cvd coating as well as worldly sputters off, you will have the ability to see these particular disintegration patterns on the target face. In the occasion of any kind of magnet issues such as missing out on, misaligned, or upside down, the erosion course will be irregular as well as this can be an excellent diagnostic sign of such issues within your Magnetron cathode. The post alignment of the private magnets have to be such that pole is formed at the facility, and also the opposite post at the perimeter. There are a couple of means to do this. One of the most typical is to mount the magnets’ north/south poles vertical to the aircraft of the target, one pole towards the target and also the other end – the complimentary end/ opposite pole – magnetically bridged to the other magnets by a pole plate constructed from magnetic usually ferrous product.