▎ 摘　　要

NOVELTY - The method involves introducing a gas containing fluorine (F2) gas as an etching gas for etching H-BN film (111) to carry out reactive ion etching, and forming a mask film (112) for patterning the H-BN film into a predetermined shape. The mask film of predetermined shape other than the H-BN film is formed. The etching gas is set as a mixed gas of F2 gas and a rare gas, and a mixing ratio of the mixed gas has a higher noble gas than that of the F2 gas. The noble gas is set as helium (He) gas. A semiconductor element is provided with a H-BN film through an insulating film in a gate film, and the insulating film and the H-BN film are functioned as a gate insulating film. USE - Method for etching hexagonal boron nitride (H-BN) film used in manufacture of semiconductor device (claimed) e.g. FET. ADVANTAGE - The etching by the F2 gas is performed while suppressing the influence of the H-BN film and the rare gas to the substrate. Multiple semiconductor elements for increasing the mobility of the graphene film are formed on the substrate, so that the degree of integration is enhanced. The semiconductor device is obtained by patterning the H-BN film into a desired shape to exhibit the effect of the H-BN film. The etching is smoothly performed to the mass production stage since confirming that the etching is accurately performed by grasping the etching effect by the F2 gas while the mixed gas of the F2 gas and the He gas is control. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a semiconductor device for etching hexagonal boron nitride film. DESCRIPTION OF DRAWING(S) - The drawing shows the cross-sectional view of the H-BN film used in manufacture of semiconductor device. (Drawing includes non-English language text) 110Substrate 111H-BN film 112Mask film 113Resist film