FORMATION OF THIN FILM

PURPOSE:To obtain a thin film having a lrge area and uniform thickness by applying vacuum evaporation or sputtering through the intermediary of meshes whose plane distribution is sparse in the center and dense at the periphery. CONSTITUTION:Under the heat from a heater and a lamp set above a substrate 5, evaporated particles from a source of evaporation get, in a lot, to the central part of the substrate where it is easily heated and its temperature is high, since meshes just under the part are sparse and therefore the rate of permeation is high. On the other hand, the evaporated particles from said source get, in a low degree, to the peripheral part of the substrate 5 which is adjacent to or in contact with a mask 6 and a supporting frame 8, from which the heat is easily radiated and at which the temperature is lower than in the central part, since meshed immediately under the peripheral part are dense and so the rate of permeation is low. The degree of adhesion of the evaporated particles is almost inversely proportional to the temperature of the substrate. Although the degree of adhesion is lower in the central part of the substrate, this is compensated by the number of the arriving particles, thereby the velocity of formation of a film is made uniform, and thus a semiconductor film having uniform thickness can be formed.