INTERMEDIATE MATERIAL FOR MANUFACTURING CIRCUIT BOARD AND METHOD FOR MANUFACTURING CIRCUIT BOARD USING SUCH INTERMEDIATE MATERIAL

摘要

An intermediate material (1001) for manufacturing a circuit board is provided with a prepreg sheet (11) whereupon a through hole (13) is formed; a first film (12A) which is arranged on one plane (11A) of the prepreg sheet and has a first hole (112A) connected to the through hole; a second film (12B) which is arranged on the other plane (11B) of the prepreg sheet and has a second hole (112B) connected to the through hole; and a conductive paste (15) filled in the through hole, the first hole and the second hole. The thickness (t₁) of the prepreg sheet, the minimum diameter (r_min) of the through hole of the prepreg sheet, the thickness (t_f1) of the first film, the diameter (r_f1) of the first hole, the thickness (t_f2) of the second sheet and the diameter (r_f2) of the second hole satisfy the following relationships; r_f1/t_f1=3, r_f2/t_f2=3, r_min/(t₁+t_f1+t_f2)=1.5. The circuit board wherein a fine via conductor is surely and stably connected to a metal foil (125) is obtained by using the intermediate material.