| 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. n 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. |