| 摘要 |
PROBLEM TO BE SOLVED: To improve heat radiation of a plastic circuit board. SOLUTION: An IC chip 12 is loaded on a plastic circuit board 11, and molded by sealing resin 14, and plural solder balls 15 are joined to the lower face of the plastic circuit board 11 so that a PBGA package 10 can be constituted. A conductive pattern is formed of copper foil or the like on the both faces of the plastic circuit board 11. The area ratio of a conductive pattern 16 to the board area is 60% or more, and preferentially, 80% or more. The conductive pattern is formed so that all boundary parts between the adjacent conductive patterns can be thin wires whose thin width is 80μm (that is, line width which is absolutely necessary for insulation between the conductive patterns). Thus, heat resistance of the plastic circuit board 11 as a whole can be reduced, and the heat radiation of an IC chip 12 can be efficiently attained in a path from the plastic circuit board 11 to a printed circuit board 19. |
