Nippon Shokubai Co., Ltd.

Shinichi Goto

Kozo Tajiri

Yoshinobu Asako

Tomomi Makino

Kumiko Kawada

A halogenated polyamide acid composition containing a halogenated polyamide acid, a metal oxide precursor, a catalyst of reaction of generating a metal oxide from the precursor, and/or a coupling agent having a reactive group. A halogenated polyimide film is obtained by, for example, carrying out the heat treatment of the halogenated polyamide acid composition. The halogenated polyimide film has a refractive index at wavelength of, for example, 1,550 nm of 1.520 or lower. Further, an optical waveguide uses the halogenated polyimide film as at least one of a core layer and a clad layer, and a relative refractive index difference between the core layer and the clad layer of the optical waveguide is, for example, 0.6 or greater. An optical waveguide device contains such an optical waveguide.

Halogenated polyamide acid composition and its applications

A method for producing a fluorine-containing polyimide film excelling in heat resistance, resistance to chemicals, water repellency, dielectric properties, electrical properties, and optical properties and a spin coater suitable for the method are to be provided. A method for the production of a fluorine-containing polyimide film which comprises forming a coating film of a fluorine-containing polyimide precursor in an atmosphere having a relative humidity thereof adjusted to a level of not more than 50 RH % and then subjecting the fluorine-containing polyimide precursor to heat treatment thereby forming a fluorine-containing polyimide film is provided. By adjusting the relative humidity in accordance with this method, the fluorine-containing polyimide precursor can be prevented from being decomposed by the absorption of moisture and consequently prevent effectively the fluorine-containing polyimide film from forming piriform spots and scratches. Further, by forming the coating film while keeping the coating film sprayed with a gas particularly during the course of spin coating thereby giving rise to a layer of air flow on the coating film, misty substances of the coating solution generated within the spin coater can be prevented from adhering again to the coating film and consequently ensure the production of a coating film of uniform quality. This formation of the layer of air flow can be facilitated by providing the spin coater with a lid and furnishing the lid with a gas feed port.

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Kakogawa, Japan

Shinichi Goto