COMPOSITE PRINTED BOARD AND METHOD FOR MOUNTING ELECTRONIC CIRCUIT BOARD

PROBLEM TO BE SOLVED: To improve the connection reliability of soldering parts of leads by reducing physical stresses caused by the thermal deformation, strain, etc., of a substrate by bringing thermocompression bonding films nearer to the soldering sections of leads and heating the thermocompression bonding films by utilizing the conduction of the heat which is generated when lead terminals are soldered. SOLUTION: Adhesive thermosetting thermocompression bonding film 9 are provided on both the front and rear surfaces of a rigid printed board 1 so that the films 9 may be in contact with the front end section of the board 1 in the leading-out direction of a soldered lead terminal 2. Then the printed board 1 is put on and temporarily fixed to a flexible printed board 5. The films 9 are stuck to the positions where both printed boards 1 and 9 are in contact with the lead terminal 2 and a thermocompression bonding head 11 having a rectangular cross section is positioned immediately above lead terminals 2 and 6 and heats the whole area of the lead terminal 6 form the rear surface side. A pressing head 13 presses the whole area of the film 9. At the time of soldering the lead terminal 6, the head 11 is raised upward after the head 11 heats the section 6 by pressing the section 6 from the rear surface side of the substrate 5 while the head is maintained at >=200 deg.C.