Abstract: An aqueous ammonia composition having low surface tension is disclosed, which comprises ammonia water and a fluoroalkylsulfonamide compound having the following general formula:R.sup.1 SO.sub.2 NR.sup.2 --X--H (I)wherein R.sup.1 represents a fluoroalkyl group, R.sup.2 represents a hydrogen atom or a lower alkyl group, X represents a grouping selected from CH.sub.2 COO and (CH.sub.2 CH.sub.2 O).sub.n, wherein n is a positive integer from 1 to 20. This aqueous ammonia composition may be mixed with an aqueous hydrogen peroxide solution and water so that it can be used for cleaning a semiconductor substrate. The cleaning solution has outstanding stability, and exhibits improved efficacy in removing microparticles of impurities and excellent surface-protecting effect on the semiconductor substrate that is useful in the manufacture of high density integrated circuit elements.

Abstract: A heat sink fan has a fan motor provided with blades, a rectangular upper casing for holding the fan motor, and a rectangular lower casing fixed to the upper casing. The lower casing has a bottom portion and fin dissipating fins erected perpendicularly from the four side edges of the bottom portion. The upper and lower casings are fixed together by a mechanically interlocking mechanism consisting of a combination of pawls and pawl receiving portions, a combination of projections each having an inflated portion and cavities or a combination of hooks and engaging grooves formed or in the upper or lower casing. Fin portions are formed on the whole area or the area except for the fan motor and the blades to increase a heat dissipating efficiency.

Abstract: A fan motor has a pair of ball bearings placed in the vicinity of each end of an inner side of a bearing race. A plurality of projections are sequentially placed circumferentially around a center portion of the bearing race to axially locate both the ball bearings. A plurality of low-profile projections are sequentially formed between neighboring projections on the inner side surface of the bearing race and are axially elongated from one installing position to that of another installing position of respective ball bearings. The ball bearings are supported by the inner side of each low-profile projection respectively at one end portion and the other end portion of the low profile-projections.

Abstract: A motor is provided which includes a housing, a stator attached to the cylindrical wall of the housing, a sleeve bearing attached to the inner periphery of the cylindrical wall, a rotor rotatably supported by the sleeve bearing, and a rotor magnet attached to the rotor. A plurality of projecting strips are formed substantially at equal intervals on the inner and/or outer periphery of the cylindrical wall of the housing. The cylindrical wall is formed into a shoulder and a mating recess. The stator has elastic pieces. Because of the operation of the elastic pieces, the stator is elastically retained between the shoulder and the mating recess. Circuitry for protecting the motor is improved.

Abstract: A fan motor having a structure which allows a stopper to keep contact with a thrust plate on a circular contact area only, by inserting a shaft through a sleeve bearing, and by attaching the stopper, against the thrust plate, onto the end portion of the shaft. This assures uniform sliding of the thrust plate against the sleeve bearing without partial contact, even if the stopper is attached in a slight inclination with respect to the thrust plate. Localized wear of the thrust plate and rubbing mechanical noise are thus prevented.