| 摘要 |
PROBLEM TO BE SOLVED: To avoid the defective connection in wire-bonding step by a method wherein an inner lead pad parts formed on the outer peripheral parts of multilayer wiring substrate wherein a power supply plane 3 and an inner lead are formed on a metallic board through the intermediary of an insulating resin layer are connected to an outer front end including an outer frame part using a conductor. SOLUTION: A metallic board 1 to be a grounding plane is coated with a sensitive resin composition for producing a specific patterned insulating resin layer 2a so as to form a power supply plane 3. Likewise, another insulating resin layer 2b is produced so as to produce a multilayer wiring substrate whereon an inner lead 4 and inner lead pad parts 5a, 5b are formed. Later, a conductor 7 formed of tin or tin-lead alloy formed on the outer lead front end 6a and the inner lead pad parts 5a or 5b formed on the outer periphery of the multilayer wiring substrate are collectively heat junctioned. Through these procedures, the bonding area of the inner lead 4 will not be polluted thereby enabling the stable wire-bonding step to be performed. |
