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US 6,190,940 B1Granted
Flip chip assembly of semiconductor IC chips
AssigneeLucent Technologies Inc.
InventorsRichard Alden DeFelice, Eric William Dittmann, Paul A. Sullivan
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AssigneeLucent Technologies Inc.
InventorsRichard Alden DeFelice, Eric William Dittmann, Paul A. Sullivan
Estimating the term…
The specification describes techniques for soldering IC chips, or other components, to interconnection substrates using a patterned epoxy layer to define the solder interconnections. The epoxy layer is photodefined to form openings that expose the bonding sites on the IC chip (or alternatively the interconnect substrate). Solder paste is deposited in the openings. With the IC chip and the interconnect substrate aligned together, the solder paste is heated to reflow the solder and solder bond the IC chip to the substrate. Heating is continued to cure the epoxy, which serves the function of the conventional underfill. The shape of the solder interconnection is defined by the lithographically formed openings, and the interconnections can be made with very fine pitch. The application of the epoxy underfill in this manner assures complete filling of the gap between the IC chip and the interconnection substrate.
A method for the manufacture of semiconductor integrated circuits (ICs) in which a first surface is bonded to a second surface by solder interconnections, said first surface having a first pattern of bonding sites and said second surface having a second pattern of bonding sites that is a mirror image of said first pattern, said solder interconnections formed by the sequential steps of:
The method of claim I wherein the solder paste is heated to a temperature in the range 170-220° C.
Dependencies are inferred from the claim text.