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Single Point ILB Solder Reflow with Pulse Heated Tip

IP.com Disclosure Number: IPCOM000110231D
Original Publication Date: 1992-Oct-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 1 page(s) / 71K

Publishing Venue

IBM

Related People

Chalco, P: AUTHOR [+2]

Abstract

The problem of highly localized solder reflow is solved by the use of a pulse-heated fine point tip which transfers heat directly to the lead in a highly controlled manner. The main applications are single-point Tape Automated Bonding (TAB) Inner Lead Bonding (ILB) and rework of defective solder joints with a very small size.

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Single Point ILB Solder Reflow with Pulse Heated Tip

      The problem of highly localized solder reflow is solved by the
use of a pulse-heated fine point tip which transfers heat directly to
the lead in a highly controlled manner.  The main applications are
single-point Tape Automated Bonding (TAB) Inner Lead Bonding (ILB)
and rework of defective solder joints with a very small size.

      Used as a primary ILB method, the pulse-heated tip insures that
the tip applies the same pressure to all leads, thus providing high
bonding yields.  In the case of rework, a typical situation is when
multiple-point reflow (gang) bonding fails to provide 100% bonding
yields.  There are many reasons for a lead not to bond to a molten
solder mass, but the main reason is non-contact during reflow.  The
most common method for reworking unbonded leads is the use of
hot-iron tools that simultaneously press the lead on the solder bump
and melt the solder.  These tools are very bulky and therefore their
use is limited to relatively large leads (wider than 15 mils).  For
ILB, where the leads are less than 2 mils wide, no tool considered
adequate to perform single-point solder reflow is available, thus
creating a serious exposure if the gang bonding process normally used
can not deliver the required yields.

      As shown in the figure, the method described consists of a
fine-point tip heated locally.  The method of heating the tip can be
laser energy or electrical resistance h...