| 摘要 |
PROBLEM TO BE SOLVED: To join an element at a low temp. without using flux by constituting a solder material of a core containing a specified quantity of tin and lead and a gold layer coating the core, heating and fusing a solder material and joining an element and a base plate. SOLUTION: A core 18 of a solder material 10 has a composition consisting of at least 30 wt.% tin, <3 wt.% gold and the balance lead. A gold layer 26 is formed on the core 18 by an electroless process. The core 18, an element 12 and a base plate 14 have a gold layer 26 of at least 0.1μm thickness. The element 12 is a microoptical electronics element. The solder material 10 has at least 50μm thickness. The solder material 10 is heated to a temp. lower than 280 deg.C and joins the element 12 and the base plate 14. A microelectronics assembly is a hybrid package 16. The core 18 is preferably made to an eutectic structure of about 63 wt.% tin and about 37 wt.% lead. |
