HIGHLY DENSE PRINTED BOARD AND MANUFACTURE THEREOF

PURPOSE:To prevent solder bridges from being produced on a highly dense printed board provided with surface-mounting pads so as to enhance the printed board in reliability of surface-mounting solder connection. CONSTITUTION:A thermosetting resin film 4 smaller than a conductor in thickness is provided to the side face of a solder connecting conductor besides a surface mount part connecting pad 5 and a gap between the adjacent connecting conductors. The conductors provided to a highly dense printed board become smaller in thickness with an increase in mounting density and are usually as thick as 35mum or below. Therefore, the thermosetting resin film 4 is set smaller than 35mum or preferably smaller than 5 to 10mum in thickness. Therefore, even if a gap between the adjacent solder connecting conductors is set smaller than 150mum or even 100mum so as to cope with a high mounting density, a highly dense printed board high enough in reliability of soldering connection for a practical use can be realized.