Semiconductor device and manufacturing the same

A semiconductor device comprising:

• a heat sink formed of a flat metallic plate having a high thermal conductivity;
• a frame fixed to a main surface of the heat sink, the frame having a frame-shaped ceramic laminate structure with wiring lines provided at predetermined positions;
• a plurality of leads projecting outside the frame, the plural leads being connected electrically and mechanically at respective inner end portions to predetermined wiring lines of the frame;
• one or plural semiconductor chips fixed to the main surface of the heat sink;
• a plurality of conductive wires for electrically connecting between the leads and predetermined electrodes of said predetermined semiconductor chip, or between the leads and predetermined electrodes of said predetermined semiconductor chip, and also between predetermined electrodes of said predetermined semiconductor chip and predetermined electrodes of said predetermined semiconductor chip;
• a metallic cap which is fixed to the frame so as to cover the semiconductor chips and the wires and seal the frame hermetically;
• and
• a screwing piece fixed superimposedly on the cap, both end portions of the screwing piece extending outside the cap in such a manner that the extending portions are bent intermediately in one step, with through spaces for screwing being formed in the bent extending portions respectively.

A method of manufacturing a semiconductor device, comprising the steps of:

• providing a lead frame and a heat sink, the lead frame being constituted by a metallic plate having one or more product forming portions of a predetermined pattern, the heat sink being constituted by a flat metallic plate of a high thermal conductivity which is fixed to the product forming portions with screws;
• fixing one or plural semiconductor chips to a main surface of the heat sink;
• superimposing the heat sink on back sides of the product forming portions of the lead frame and fixing the heat sink to the lead frame with screws from a main surface side of the lead frame;
• connecting between electrodes of the semiconductor chips and inner ends of corresponding leads and also between predetermined electrodes of predetermined semiconductor chips, using conductive wires;
• covering the main surface side of the heat sink and a predetermined portion of the lead frame with an insulating resin by one-side transfer molding to form an insulating seal member;
• and
• cutting off an unnecessary portion of the lead frame, allowing a back side of the heat sink which is insulative to be exposed to a back side of the seal member and allowing the leads to be projected from side faces of the seal member,
• the product forming portions each comprising:
• a pair of screwing pieces having respective inner end portions connected with screws respectively to right and left ends of the heat sink on the main surface side of the heat sink, the screwing pieces further having outer end portions projecting to the exterior of the seal member, the outer end portions having respective through spaces for screwing which are used at the time of mounting the semiconductor device;
• a first lead having an inner end portion which is positioned within the seal member and whose inner end is arranged near one side face of the heat sink and further having an outer end portion projecting from the seal member;
• and
• a second lead having an inner end portion positioned within the seal member and near another side face of the heat sink and further having an outer end portion projecting from the seal member,
• wherein in the step of cutting off the unnecessary portion of the lead frame, or thereafter, the leads projecting from the side faces of the seal member are bent in one step to form surface-mounted type leads.