METHOD OF MANUFACTURING DIAMOND FILM AND COMPOSITE SUBSTRATE USED FOR THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a method of manufacturing a diamond film capable of obtaining a diamond film having a main surface of a large area, small in warpage, little in generation of crack and good in crystallinity at a low cost, and a composite substrate used for it.SOLUTION: A method of manufacturing a diamond film includes a process in which a composite substrate 10 containing an acid-soluble supporting substrate 11 and a single crystal film 13 which is located on the main surface 11m side of the supporting substrate 11 via an adhesive layer 12 and having a coefficient of thermal expansion in the main surface 11m of the supporting substrate 11 which is greater than 0.8 times and smaller than 1.2 times that of diamond crystal is prepared, and a process in which diamond film 20 is formed on the main surface 13m of the single crystal film 13 located on the main surface 11m of the supporting substrate 11. The method further includes a process in which the supporting substrate 11 and the adhesive layer 12 are removed by dissolving in an acid after the process in which the diamond film is formed.