Comparison of DC and AC arc thin film deposition techniques

DC and AC vacuum are evaporation comprise two techniques currently implemen ted for thin him deposition, each with specific technical aspects with rega rd to the discharge systems and their application fields. The DC are discha rge at several 10 A up to 300 A is a well-established PVD technique to depo sit hard coatings for a variety of applications. Examples of applications b enefiting from this technique are cutting and forming tools. The primary fu nction of hard coatings in this instance is to reduce friction and wear, an d the standard coating materials employed are TiN, CrN, TiCN and AlTiN. In today's manufacturing industries, machines are designed to be fully automat ed to simplify the coating process which contains several steps like heatin g, cleaning and deposition. In contrast, AC are discharges are characterized by the repetition of short current pulses up to several 1000 A. They offer new possibilities includin g an increase of average current. This is especially important for applicat ions that require plasma filtering to reduce or even avoid droplet depositi on on substrates. Yet another useful property is the increase of plasma ion ization compared to DC discharges. Applications like hard-amorphous carbon deposition and metal-interconnect deposition schemes in the semiconductor i ndustry benefit from these superior plasma conditions. AC systems could be effectively introduced to industry by using the already well-established DC equipment base. Attaching AC evaporators to convention al systems serves customers in the coating market with new flexibility whil e maintaining the production proven reliability of their investments. (C) 1 999 Elsevier Science S.A. All rights reserved.