being fine particles preferable to the film-forming, some of them do not cover the substrate but adhere to the inside wall of the film forming chamber, and problems occur as under.
In the above mentioned apparatus, the structure of the inside wall of the film forming chamber accommodating the substrate is not described. Therefore, if the inside wall is the same material as that composing the film forming chamber, fine particles once adhered to the inside wall drop and mix into the film to probably deteriorate a film quality.
This invention has been established to settle the above described problems. Accordingly, it is an object of the invention to provide a film forming apparatus which forms on a substrate a film being mixed with little coarse or fine particles, andexcellent in smoothness, adhesion and quality, and which is good at operating performance such as maintenance of low cost.
The above mentioned object can be achieved by a film forming apparatus according to the invention, comprising: a vacuum arc evaporation source, a film forming chamber, and a curved plasma duct. The vacuum arc evaporation source generates plasma containing cathode materials by evaporating a cathode through vacuum arc discharge. The film forming chamber accommodates a substrate therein and is vacuum-evacuated. The curved plasma duct has outside thereof a deflection magnetic field forming unit for guiding the plasma generated in the vacuum arc evaporation source in the vicinity of the substrate having removed coarse particles by the curved plasma duct. In the film forming apparatus, the plasma duct has a porous