Dry etching method

Abstract

Abstract PURPOSE:To permit a damage-free anisotropic dry etching at a relatively low temperature without employing any plasma, by a method wherein, when a material to be etched is irradiated with ultraviolet or far ultraviolet light so as to be etched, a material which sufficiently absorbs or reflects the irradiation ray is employed as an etching mask. CONSTITUTION:It is conjectured that a hole 16 is produced in an undoped polycrystalline Si 15 due to the fact that the ultraviolet light passing through an SiO2 mask 14 enters the polycrystalline Si 15 to excite the Si-Si bond to react with the Cl atom adsorbed on the wall and photodissociated. On the other hand, it is considered that a large undercut in a phosphorus-added polycrystalline silicon 10 under an SiO2 mask is formed due to the fact that the formation of the hole 16 speedily progresses since P and Cl easily react with each other and therefore easily form a volatile gas, such as PCl5, and additionally, the polycrystalline silicon is etched by the rise in temperature of the substrate due to the irradiation with light. In view of the above-described facts, it is possible to attain a damage-free anisotropic etching employing no plasma by selecting a material which absorbs or reflects ultraviolet light as etching masks 13, 19.

Inventors

• 👤 Haruo Okano
• 👤 晴雄 岡野
• 👤 Yasuhiro Horiike
• 👤 靖浩 堀池
• 👤 Makoto Sekine
• 👤 誠 関根

Bibliographic Details