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Dual Pitch Outer Lead Bonding Lead for Liquid Crystal Display Driver Tab

IP.com Disclosure Number: IPCOM000117232D
Original Publication Date: 1996-Jan-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Ogawa, H: AUTHOR [+3]

Abstract

This article describes a Dual Pitch Outer Lead Bonding (OLB) Lead for Liquid Crystal Display (LCD) Driver Tape Automated Bonding (TAB) which improves a yield at OLB process with fine pitch TAB and makes it possible to design a fine dot pitch LCD.

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This is the abbreviated version, containing approximately 94% of the total text.

Dual Pitch Outer Lead Bonding Lead for Liquid Crystal Display Driver
Tab

      This article describes a Dual Pitch Outer Lead Bonding (OLB)
Lead for Liquid Crystal Display (LCD) Driver Tape Automated Bonding
(TAB) which improves a yield at OLB process with fine pitch TAB and
makes it possible to design a fine dot pitch LCD.

      LCD Driver TAB is connected with Anisotropic Conductive Film
(ACF).  Minimum lapping width is specified to meet a reliability
requirement.  And wider lead has more allowance to meet this lapping
requirement.  Off location of TAB OLB lead which fail to meet Minimum
lapping width is one of a process yield detractors.  This problem is
caused by TAB Tape expansion due to heater head and tool alignment
accuracy.  And finer pitch OLB has less process margin because of
less lead width.  Ordinarily, TAB Outer Lead has equal pith on all
leads.  In this case, improving a process yield requires equipment
accuracy improvement and TAB tape accuracy improvement.

      This idea is to make a TAB tape with dual pitch outer leads.
Center part has finer lead pitch and outer part has coarser one but
total tape width must be same as ordinary TAB tape width.  Tape
expansion during OL bonding and tape pitch accuracy depend on a
distance from neutral point (center of tape).  So both end leads
which normally fail to meet a specification have wider lead and this
allows to have more process margin for off location.  If this idea is
applied for 68 mic...