Browse Prior Art Database

Methods for Preventing Tab Leads From Heat Damage

IP.com Disclosure Number: IPCOM000100332D
Original Publication Date: 1990-Apr-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 1 page(s) / 31K

Publishing Venue

IBM

Related People

Noyan, I: AUTHOR [+2]

Abstract

Disclosed are two methods for protecting the organic substrates of TAB or Flex structures from heat damage when the conductors in such structures are subjected to heat through inner-lead or outer-lead bonding operations, lead-end forming or heat-treating operations, etc.

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Methods for Preventing Tab Leads From Heat Damage

       Disclosed are two methods for protecting the organic
substrates of TAB or Flex structures from heat damage when the
conductors in such structures are subjected to heat through
inner-lead or outer-lead bonding operations, lead-end forming or
heat-treating operations, etc.

      When the conductor leads in TAB or FLEX structures are heated
in laser treatment or bonding operations, heat travels up the lead
and affects the organic substrate. Because the heat capacity of most
leads are very small, the interface between the lead and the
substrate frequently weakens, or is destroyed through irreversible
heat damage, such as charring.  This is detrimental to product
quality, causing accelerated corrosion, leaking and, in extreme
cases, shorting.

      Such damage can be minimized by manufacturing TAB or FLEX leads
with geometries that have high internal heat capacity, high radiative
power, cooling these leads by external means before the lead reaches
the substrate or by a combination of the above.  A representative
drawing is shown in the figure.