Browse Prior Art Database

Solder Reflow Flip Chip Pad Transfers

IP.com Disclosure Number: IPCOM000086212D
Original Publication Date: 1976-Aug-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Aimi, BR: AUTHOR [+2]

Abstract

In the manufacture of multilevel semiconductor chips having more than one level of interconnection metallurgy and using the solder reflow technique for substrate mounting, it is important especially where a polymer is used as a passivating or insulating layer to have both a) good thermal coupling to the substrate, and b) insulation from the lower level metallization.

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Solder Reflow Flip Chip Pad Transfers

In the manufacture of multilevel semiconductor chips having more than one level of interconnection metallurgy and using the solder reflow technique for substrate mounting, it is important especially where a polymer is used as a passivating or insulating layer to have both a) good thermal coupling to the substrate, and b) insulation from the lower level metallization.

This may be accomplished by providing a structure illustrated in the drawing.

The figure shows the first level metallization 1 having a superimposed layer of quartz 2 and a second passivation layer 3, which is polymeric; the second level of metal 4 is passivated by a polymeric layer 5. The ball limiting metallurgy 6 bonds the second level of metal 4 to the solder pad 8 as shown at 7. The second level of metal 4 connects the transferred pad to the first level of metallurgy 1 as shown at 9.

This technique lowers the pads to the quartz or first level passivation layer 2, thereby decreasing thermal resistance to the substrate while preserving the design flexibility of pad transfer at almost negligible impact upon chip temperature.

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