Abstract: A solder layer and an electronic device bonding substrate having high bonding strength of a device and low bonding failure even by a simplified bonding method of a device to a substrate and a method for manufacturing the same are provided. A device bonding substrate 1 including a substrate 2 and a lead free solder layer 5 formed on said substrate has a solder layer 5 consisting of a plurality of layers having mutually different phases, and oxygen concentration on the upper surface of the solder layer is lower than 30 atomic % of the concentration of the metal component which is the most oxidizable among the metal components making up the upper layer of the solder layer 5. Carbon concentration on the upper surface of the solder layer 5 may be lower than 10 atomic % of the concentration of the metal component which is the most oxidizable among the metal components making up the upper layer of the solder layer.

Abstract: A solder layer, a substrate for device joining utilizing the same and a method of manufacturing the substrate are provided whereby the device joined remains thermally unaffected, an initial bonding strength in solder joint is enhanced and the device can be soldered reliably. The solder layer formed on a base substrate (2) consists of a plurality of layers (5a) of a solder free from lead, which are different in its phase from one another. They are constituted by a layer of a phase that is completely melted, and a layer of a phase that is not completely melted at a temperature not less than a eutectic temperature of the solder. The solder layer (5) can be applied to a device joining substrate (1) comprising an electrode layer (4) formed on the base substrate (2) and the solder layer (5) formed on the electrode layer.

Abstract: A solder layer, a substrate for device joining utilizing the same and a method of manufacturing the substrate are provided whereby the device joined remains thermally unaffected, an initial bonding strength in solder joint is enhanced and the device can be soldered reliably. The solder layer formed on a base substrate (2) consists of a plurality of layers (5a) of a solder free from lead, which are different in its phase from one another. They are constituted by a layer of a phase that is completely melted, and a layer of a phase that is not completely melted at a temperature not less than a eutectic temperature of the solder. The solder layer (5) can be applied to a device joining substrate (1) comprising an electrode layer (4) formed on the base substrate (2) and the solder layer (5) formed on the electrode layer.

Abstract: A solder layer and an electronic device bonding substrate having high bonding strength of a device and low bonding failure even by a simplified bonding method of a device to a substrate and a method for manufacturing the same are provided. A device bonding substrate 1 including a substrate 2 and a lead free solder layer 5 formed on said substrate has a solder layer 5 consisting of a plurality of layers having mutually different phases, and oxygen concentration on the upper surface of the solder layer is lower than 30 atomic % of the concentration of the metal component which is the most oxidizable among the metal components making up the upper layer of the solder layer 5. Carbon concentration on the upper surface of the solder layer 5 may be lower than 10 atomic % of the concentration of the metal component which is the most oxidizable among the metal components making up the upper layer of the solder layer.

Abstract: A solder layer and an electronic device bonding substrate using the layer are provided which avoid deteriorating qualities of the electronic device to be bonded. In a solder layer 14 free from lead and formed on a substrate 11 or an electronic device bonding substrate 10 having such a solder layer, the solder layer 14 has a specific resistance of not more than 0.4 ?·?m. The electronic device bonding substrate 10 can have a thermal resistance of not more than 0.5 K/W and a thickness of not more than 10 ?m. Then, voids contained in the solder layer 14 have a maximum diameter of not more than 0.5 ?m and the substrate can be a submount substrate.