METHOD FOR FORMING BUMP OF SEMICONDUCTOR ELEMENT AND SEMICONDUCTOR ELEMENT

PROBLEM TO BE SOLVED: To easily form a bump which is strong against fatigue breakdown by making thinner the center part being sandwiched by an electrode pad side and the other edge side than each end face of the bump of a semiconductor element where the bump is formed at an electrode pad. SOLUTION:...

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Bibliographische Detailangaben
Hauptverfasser: TAMAGAWA MICHIAKI, SASAKI HIROYUKI, KOYAMA SHIGEAKI
Format: Patent
Sprache:eng
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Zusammenfassung:PROBLEM TO BE SOLVED: To easily form a bump which is strong against fatigue breakdown by making thinner the center part being sandwiched by an electrode pad side and the other edge side than each end face of the bump of a semiconductor element where the bump is formed at an electrode pad. SOLUTION: A mask 23 is arranged on a second polyimide resin layer, is exposed to light, and developed, thus forming a second through hole 24-2 in inverse taper shape with a sharp tip on a second polyimide resin layer 22-2. After that, a resist which is filled into a first through hole being formed at a first polyimide resin layer 22-1 is eliminated and a through hole with a thin and hand-drum-shaped through hole is formed. Then, solder paste or molten solder is filled into the through hole, thus forming a hand-drum-shaped bump 27 where a middle part in longitudinal direction is strained at all of an electrode pad 11a of each chip on a semiconductor wafer 21. To fill molten solder into the through hole, for example, a solder ball which is placed at the opening of the through hole should be melted in vacuum and returned to air.