Abstract: The present invention provides a package whose heat dissipation performance by a semiconductor device has been improved, which synchronizes with the rapid development of high transmission density in multiplex communications. In place of the conventional package substrate, a substrate formed by a combination of two or more kinds of materials is used, whereby the temperature of a portion at which the temperature tends to rise to become extremely high within the package is selectively dissipated, whereby the heat dissipation performance of the package is efficiently improved. A diamond coated substrate or diamond substrate is used at a portion with an extremely high temperature for dissipating the heat.

Abstract: Packages are required to have high heat-dissipating quality. To fulfill this requirement, a highly heat-conductive material has been used for a package's bottom plate. This results in the use of a material that has a considerable difference in the coefficient of linear expansion between the side plate and bottom plate. Notwithstanding the use of this type of material, the package must be free from reduction in airtightness and degradation in optical coupling. The package of the present invention comprises side plate 1 and bottom plate 2 each having tenons 3. The tenon portions are combined and bonded. It is desirable that tenons 3 have a width not less than 1 mm and not more than 5 mm.

Abstract: The present invention provides a package whose heat dissipation performance by a semiconductor device has been improved, which synchronizes with the rapid development of high transmission density in multiplex communications. In place of the conventional package substrate, a substrate formed by a combination of two or more kinds of materials is used, whereby the temperature of a portion at which the temperature tends to rise to become extremely high within the package is selectively dissipated, whereby the heat dissipation performance of the package is efficiently improved. A diamond coated substrate or diamond substrate is used at a portion with an extremely high temperature for dissipating the heat.