Package structure for semiconductor devices and method of manufacturing the same

A package structure for a semiconductor device having a lead electrode comprising:

• an electrically conductive cap having a flange at a circumference thereof,
• a circuit substrate having a ceramic substrate member, a first surface covered with said conductive cap and sealed air-tightly, a second surface having electrically conductive patterns for providing thereon external electrodes, and projections of high-temperature solder having a melting point of approximately 240.degree.-330.degree. C. are formed on said conductive patterns,
• wherein said circuit substrate comprises:
• a first electrically conductive layer on said first surface of said circuit substrate extending along an outer circumference of said circuit substrate,
• a second electrically conductive layer covering said second surface of said circuit substrate, said second conductive layer being formed substantially entirely over said second surface of said circuit substrate except having a portion for said lead electrode of said semiconductor device,
• a plurality of electrically conductive through-holes, disposed uniformly in said circuit substrate directly below said first conductive layer and said flange, for connecting said first conductive layer with said second conductive layer, and
• electrically conductive sealing means for sealing contact surfaces of said flange of the conductive cap to said first conductive layer.