Antireflection film, antireflection film manufacturing method, and semiconductor device using the antireflection film

To improve a transmission rate of an antireflection film, the antireflection film includes: a first silicon oxide film (2), which is formed on a silicon substrate (1); a polysilicon film (3), which is formed on the first silicon oxide film (2) to a thickness of 6 nm through 14 nm; and a second silicon oxide film (4), which is formed on the polysilicon film (3). The transmission rate of the antireflection film is further improved if a thickness of the first silicon oxide film (2) is set to 14 nm through 35 nm. When used in a photoelectric conversion element for such as a solid state image sensor and a photovoltaic generator, the antireflection film may enhance efficiency of photoelectric conversion.