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Repair Method of Chip On Glass With Anisotropic Conductive Film

IP.com Disclosure Number: IPCOM000121470D
Original Publication Date: 1991-Sep-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Sakamoto, K: AUTHOR [+2]

Abstract

Disclosed is a repairable chip on glass (COG) packaging method with an anisotropic conductive film (ACF) for a liquid crystal display (LCD). This is a two-step bonding method, which enables repair of the bad chip.

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Repair Method of Chip On Glass With Anisotropic Conductive Film

      Disclosed is a repairable chip on glass (COG) packaging
method with an anisotropic conductive film (ACF) for a liquid crystal
display (LCD).  This is a two-step bonding method, which enables
repair of the bad chip.

      Fig. 1 shows the process flow chart of the two-step bonding.
The ACF consists of epoxy adhesive and conductive particles of 5 to
10 micrometer diameter nickel. The chip cannot be removed easily when
the ACF is cured completely because of high adhesion strength. The
two- step bonding is required to enable replacing bad chips. The
first bonding temperature must be lower than the second bonding
temperature to remove the chip, but it must be a high enough
temperature to estab lish good contact between electrodes. After the
inspection of interconnection, the second bonding is made with
sufficiently high temperature to achieve full cure of epoxy.

      Fig. 2 shows the repair condition. When the first bonding
temperature is 90 to 140 (oC), the chip can be repaired.

      The resistance between electrodes (the chip and the glass) is
stable in any case (after first bonding, after second bonding after
repair).

      The second bonding parameters are as follows:
           temperature :180(oC)
           pressure    :3(kg/chip)
           time        :60(sec)