Browse Prior Art Database

Protective Coating between Chip and Substrate

IP.com Disclosure Number: IPCOM000085742D
Original Publication Date: 1976-May-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Lane, R: AUTHOR

Abstract

In all flip-chip bonding, some form of protective coating is needed between the chip, and the substrate. This coating must cover the delineated line pattern and the solder connection between the chip and the line pattern. This protection is even more critical in the ink jet printing technology because of the ever present humidity introduced by the ink.

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Protective Coating between Chip and Substrate

In all flip-chip bonding, some form of protective coating is needed between the chip, and the substrate. This coating must cover the delineated line pattern and the solder connection between the chip and the line pattern. This protection is even more critical in the ink jet printing technology because of the ever present humidity introduced by the ink.

The process described has been preformed using a silicon charge chip and a delineated copper-clad epoxy board. The figure shows a cross section of a silicon charge chip 2 soldered by solder balls 3 and 4 to delineated copper lines 5 on a delineated epoxy board 6. A filter paper 7 is placed over through slots 8 in the silicon charge chip 2, so that the only vacuum leak is between the chip 2 and the board 6. A TYGON* hose 9 is connected to the board 6 and a vacuum source, not shown. Accordingly, a vacuum is produced below a hole 10 in the epoxy board 6. A 1:1 solution of No Arc** and trichlorethylene is then applied to the edges of the chip 2, and the vacuum draws the solution between the board 6 and the chip 2. The amount of solution drawn by the vacuum is dependent upon how long the vacuum is applied and the drying time of the solution.

The same concept is applicable to protecting a C4 bonding. A hole is made in a substrate prior to bonding. If the substrate is ceramic, the hole is made in the green sheet. Any protective solution can be used as long as it flows under th...