Hitachi, Ltd.

Kenji Sugimoto

Shunichiro Kuwatsuka

Fusaji Shoji

Haruhiko Matsuyama

Eisei Togawa

Saburo Suzuki

A method of producing a thin film magnetic head by successively depositing on a substrate a first magnetic material, a gap material, an electrically conductive material consisting of a coil, an insulating film, a second magnetic material and a protecting film, wherein the improvement comprises a step for forming a recessed portion in the insulating film at a portion corresponding to a gap portion on the air bearing surface side, the bottom surface of said recessed portion serving as an exposed portion on the upper surface of the gap material and the side surfaces of said recessed portion being tapered, a step for forming a recessed portion in the gap material by etching using the insulating film with the recessed portion as a mask and making the thickness thereof equal to the gap length, and a step for depositing a second magnetic material on the whole surface, so that the recessed portion formed in the gap material will have a rectangular shape with its one side being equal to a gap depth and its another side being equal to a track width. Unlike the conventional art, no thick photoresist film is used in a step for determining the gap depth and the track width, making it possible to obtain a thin film magnetic head having a small gap depth and a narrow track width maintaining high precision.

Method of producing a thin film magnetic head

A thin film magnetic head of which the insulation layer is made of a polyimide resin obtained by heat-curing a polyimide precursor represented by the following general formula (I) or (II) or a mixture thereof not only has excellent characteristics with respect to the insulation layer, i.e. satisfactory flatness, high glass transition temperature and excellent adhesiveness but also is free from film defects, i.e., exhibits high reliability: ##STR1## wherein R is, e.g., ##STR2## Ar.sup.1 is, e.g., ##STR3## Ar.sup.2 is, e.g. ##STR4## n is an integer of 1 to 100, and m is an integer of 10 to 500.

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Odawara, Japan

Kenji Sugimoto