Lead frame and resin-molded-type semiconductor device

A lead frame for a resin-molded-type semiconductor device, said lead frame comprising:

• a chip mount board on which a semiconductor chip is to be mounted, said chip mount board comprising an electrically insulated substrate and conductive patterns formed on said insulated substrate;
• and
• a lead frame body including a plurality of leads arranged side by side to constitute a co-planar structure and having inner leads electrically connected to said conductive patterns on the chip mount board to be electrically connected to said semiconductor chip, said plurality of leads comprising:
• at least one first lead to be used as a signal lead and at least two second leads to be used as ground or power supply leads arranged at the sides of said signal lead wherein said second leads are not integrally formed with the die-pad, but individually formed to be separate therefrom, and
• each of said signal leads having a predetermined lead width and predetermined distances to the adjacent ground or supply leads, said width and said distances being determined in such a manner that said signal leads have a desired characteristic impedance.

A resin-molded-type semiconductor device comprising:

• a chip mount board comprising an electrically insulated substrate and conductive patterns formed on said insulation substrate;
• and
• a lead frame comprising:
• a plurality of leads arranged side by side to constitute a co-planar structure and having inner lead portions electrically connected to said conductive patterns on the chip mount board, said plurality of leads comprising:
• at least one first lead to be used as a signal lead and at least two second leads to be used as ground on power supply leads arranged at the sides of said signal lead, said second leads are not integrally formed with the die-pad, but individually formed to be separate therefrom;
• each of said signal lead having a predetermined lead width and predetermined distances to the adjacent ground or power supply leads, said width and said distances being determined in such a manner that said signal lead has a desired characteristic impedance;
• a semiconductor chip mounted on said chip mount board;
• connecting means for electrically connecting said semiconductor chip to said conductive patterns formed on chip mount board;
• and
• a hermetically-sealed resin molding containing at least said semiconductor chip, said chip mount board, said connecting means and said inner lead portion.