Method for forming solder bumps
AssigneeFujitsu Limited
InventorsMasayuki Ochiai, Yasuo Yamagishi, Ichiro Yamaguchi, Masahiro Yoshikawa, Koki Otake, Masataka Mizukoshi, Yuuji Watanabe
Life of this patent
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Abstract
Method for forming solder bumps on a first member such as a semiconductor chip having electrode pads formed thereon. A flat plate having holes is prepared and the holes are filled with solder paste by squeezing. The flat plate is then overlapped with the first member with the flat plate above the first plate. The flat plate and the first member are heated to a temperature higher than the melting point of the solder alloy in the solder paste. Therefore, solder bumps having identical sizes and uniform structures can be obtained.
Claims6
A method for forming solder bumps, comprising the steps of:
- filling holes of a flat plate with a solder paste by squeezing;
- heating the flat plate to a temperature higher than the melting point of the solder to form solder balls from the solder paste in the holes of the flat plate;
- removing an oxidation layer on electrode pads of an electric component arranged at positions corresponding to those of the holes of the flat plate;
- after said removing step, overlapping the flat plate with the electric component one above another while the solder balls are positioned relative to the electrode pads;
- and
- after said overlapping step, heating the flat plate and the electric component overlapped with each other to a temperature higher than the melting point of the solder to transfer the solder balls from the flat plate to the electric component.
Dependencies are inferred from the claim text.