| 摘要 |
PROBLEM TO BE SOLVED: To provide a printed circuit board unit and a printed wiring board capable of joining lands reliably. SOLUTION: An adhesive sheet 51 composed of a thermosetting resin is put between conductive lands 31, 41. Conductive cement 53 is placed between the conductive lands 31, 41 in an opening 52 formed at the adhesive sheet 51. The conductive cement 53 contains a matrix material containing a thermosetting resin and a filler formed of a copper particle that is dispersed into the matrix material and has a surface coated with a tin bismuth alloy. The conductive land 41 is pressed against the conductive land 31. At the same time, heat is applied to the adhesive sheet 51 and the conductive cement 53. A copper tin alloy layer is formed on the surface of the copper particle. A gap is filled with bismuth. COPYRIGHT: (C)2010,JPO&INPIT |
