Author: Gonzalez, Winder A. ; Type of thesis: Master Thesis
Abstract:
Vacuum coating processes use a vacuum environment and an atomic or molecular condensable vapor source to deposit thin films, typically less than 5µm in thickness. An example of such a process is magnetron sputtering where material is removed from a solid target by ion bombardment and deposited on a substrate in atomic layers. It is one of the most flexible and controllable methods of generating a metal vapour in vacuum. Applications include low friction coatings for tools, antireflective coatings on glass, semiconductors, decorative coatings e.g. bath taps, touch panel screens, car headlamps, telescope mirrors and coatings for photovoltaics.
A magnetron sputtering source is composed by a cathode, an anode and a combined electric and magnetic field. There are various types of magnetron depending on the application and the target efficiency required. Each type requires an optimized design of magnetic field to ensure operation of the magnetron source. As the price of raw materials becomes higher, the efficiency of the usage of the deposition materials also becomes an important concern.
The purpose of a magnetic field in a sputtering plasma is to increase the efficiency of ionization by capturing electrons emitted from the target to enlarge the rate of the collisions between electrons and neutral gas atoms. The lack of uniformity of the magnetic field produces a non-uniform plasma density, hence differential sputtering rates across the surface of the target. It is obvious that increasing uniformity of the magnetic field will improve the uniformity of the erosion of the target.
This thesis shows the setup of a d.c. magnetron sputtering configuration for a 4″ diameter Copper target, based on a computational study of different magnetic confinements, as well as with an optimization …..
of the erosion sputtered from the target.