Direct Chip Bonding for Liquid Crystal Display

Direct Chip Bonding for Liquid Crystal Display

      Disclosed is a technique for interconnecting a driver IC
chip directly on the surface of a glass substrate. This technique is
widely applicable to any hybrid device and any flat panel display.

      Fig. 1 shows the bonding structure of this new technique and
Fig.  2 shows the process steps of this new technique.  As shown in
Fig. 1, the bonding structure is comprised of a thermosetting-type
epoxy adhesive, a gold bump with tail which is fabricated upon an IC
chip's electrode using a ball bonding method (a wire bonder).

      The epoxy adhesive is printed on the top of the gold bump with
a precisely controlled thickness.

      The interconnection is achieved by applying pressure and heat.
The pressure enables the gold bump's tail to penetrate into the
electrode on the substrate.  Then, the heat cures the epoxy resin to
maintain the interconnection. After this process, encapsulation resin
is injected between the chip and the LCD substrate for humidity
prevention.

      According to this structure, both a high insulation resistance
between adjacent pads and a high electrical conductivity
interconnection are achieved.