PURPOSE: To surely form a dielectric buried layer inside a substrate by forming a dielectric layer on a substrate surface which is equivalent to a recessed region when forming both semiconductor substrates before a junction process of first and second semiconductor substrates.
CONSTITUTION: A recessed part 2 is formed on a part of a mirror surface 1a of a first semiconductor substrate 1. A groove 3 whose values of both width and depth are larger than those of the recessed part 2 is formed along an area near a boundary with the mirror surface 1a of the recessed part 2. An Si nitride film 4 is formed on a surface having the recessed part 2 and the groove 3 of the substrate 1 to expose a surface of the recessed part 2 and the groove 3. A heat oxidation Si layer 5 is formed only on a surface of the recessed part 2 and groove 3 exposed by heat treatment to remove the film 4. Thereafter, mirror surfaces 1a, 6a of two sheets of first substrate 1 and second substrate 6 are adhered mutually. Accordingly, it is possible to enable sure formation of the buried layer 5 inside the substrate 10.
MATSUI MASAKI
KATADA MITSUTAKA
TSURUTA KAZUHIRO
