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US 10,950,573 B2Granted
Lead-free column interconnect
AssigneeInternational Business Machines Corporation
InventorsCharles L. Arvin, Clement J. Fortin, Christopher D. Muzzy, Krishna R. Tunga, Thomas Weiss
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Abstract
Disclosed are interconnects in which one substrate having a high melting temperature, lead-free solder column is joined to a second substrate having openings filled with a low melting temperature, lead-free solder such that the high melting temperature, lead-free solder column penetrates into the low melting temperature, lead-free solder so as to obtain a short moment arm of solder.
Claims9
A method of interconnecting using a lead-free column, the method comprising:
- depositing metallization for an underbump metallurgy (UBM) on a semiconductor device;
- forming a copper pillar on the UBM, the copper pillar having an end;
- plating a high melting temperature, lead-free solder on a portion of the end such that an area of the portion is less than an area of the end so as to leave an exposed portion of the end that is not covered by the high melting temperature, lead-free solder;
- etching the copper pillar that is not covered by the high melting temperature, lead-free solder;
- contacting the high melting temperature, lead-free solder to a low melting temperature, lead-free solder on a laminate substrate;
- and
- reflowing the low melting temperature, lead-free solder so that the high melting, lead-free solder and copper pillar penetrate into the reflowed low melting, lead-free solder a predetermined distance.
4 more elements
Dependencies are inferred from the claim text.