Abstract: An electrode-pin forming mask is used to form electrode pins on the semiconductor chip. The electrode-pin forming mask has electrode-pin forming holes matching electrode pads previously formed on the semiconductor chip. A screen-printing technique is used to form the electrode pins on the semiconductor chip through the electrode-pin forming mask. That is, conductive material in a paste state is pushed into the electrode-pin forming holes in a condition where the electrode-pin forming mask has been placed on the semiconductor chip and positions of the electrode-pin forming holes match positions of the electrode pads of the semiconductor chip, respectively. The conductor material thus pushed into the electrode-pin forming holes is thus shaped as to form the electrode pins projecting from the electrode pads of the semiconductor chip.

Abstract: A heterojunction bipolar transistor includes a tungsten layer formed on a base layer. An insulating sidewall is formed on the base layer and along a vertical wall of an emitter layer formed on the base layer. An end of the tungsten layer faces a base-emitter heterojunction through the sidewall.

Abstract: A uniform mixture of a polytetrafluoroethylene molding powder and an organic filler, which can provide moldings having improved properties without lowering the appearance and mechanical property, is obtained without sticking the filler to the wall of a mixer by mixing the molding powder and the filler in the presence of a silane coupling agent and a polar solvent, or by previously treating the organic filler with the silane coupling agent and mixing the treated filler with the molding powder.