Method for forming thin film, spheroid coated with thin film, light bulb using the spheroid and equipment for film formation

Abstract

The present invention provides a method for forming thin films, wherein thin films with a uniform thickness can be formed on substrates as objects such as spheroids, even when the films are formed by conventional film-formation methods using an incident particle beam coming from a specific direction (e.g., evaporation and sputtering). In the method, thin films are formed on substrates such as spheroids with an incident particle beam coming from a particle source located in a specific direction by performing a spin motion together with a swing motion. The spin motion is a rotation of the substrate at a constant angular velocity about the spheroidal axis. The swing motion is a rotational oscillation of the same substrate for rotationally oscillating the axis at a constant cycle in one surface, where the center of the rotational oscillation is in the vicinity of the midpoint between two focal points on the axis of the spheroid. As a result, thin films with a uniform thickness in both the peripheral direction of the substrate and in the rotational axis direction of the spin motion can be formed even on substrates including spheroids.