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Laser-Induced Platinum Deposition for Improved EC Wiring of Thin-Film Modules

IP.com Disclosure Number: IPCOM000102688D
Original Publication Date: 1990-Dec-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 99K

Publishing Venue

IBM

Related People

Baum, TH: AUTHOR [+4]

Abstract

Current high end packaging products use discrete, ultrasonically bonded wires to achieve engineering changes (ECs) or circuit modifications. These engineering changes or modifications in wiring nets are needed to correct design errors, correct defects in the substrate wiring or to customize the function of the specific packaging module. With increased performance, the wiring density of the substrate increases and the redistribution layers will move to the top surface and, thus, limit the useable top-surface area. The overall feature dimensions become smaller, the available space for making engineering change pads is limited and the size of the EC pad shrinks beyond the size of that which is capable of being bonded to by traditional wire bonding techniques.

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Laser-Induced Platinum Deposition for Improved EC Wiring of Thin-Film Modules

       Current high end packaging products use discrete,
ultrasonically bonded wires to achieve engineering changes (ECs) or
circuit modifications.  These engineering changes or modifications in
wiring nets are needed to correct design errors, correct defects in
the substrate wiring or to customize the function of the specific
packaging module. With increased performance, the wiring density of
the substrate increases and the redistribution layers will move to
the top surface and, thus, limit the useable top-surface area.  The
overall feature dimensions become smaller, the available space for
making engineering change pads is limited and the size of the EC pad
shrinks beyond the size of that which is capable of being bonded to
by traditional wire bonding techniques.

      The laser-induced chemical vapor deposition (LCVD) of
high-purity metals offers an alternate, selective metallization
technique for making engineering changes onto packaging modules.  The
technique involves the selective pyrolysis of a volatile
metal-containing precursor which can be decomposed to high-purity
metal.  The metal precursor used in the laser process is critical
because its chemical and physical properties directly affect the
laser deposition process.  For example, the vapor pressure can
determine the observed rates of deposit formation.  The use of noble
metal thin-films are desirable for microelectronics applications
because the films are less likely to degrade upon exposure to high
electrical currents, high operating temperatures, corrosive
conditions of temperature and humidity, and during exposure to
chemical processing environments after the metal has been deposited.

      The laser-induced pyrolytic deposition of platinum metal has
been utilized to deposit electrically conductive EC connections onto
thin- film packaging modules.  Pyrolytic decomposition of tetrakis
(trifluorophosphine) platinum, Pt(PF3)4, using focussed visible light
from an argon ion laser results in the formation of high-purity
platinum metal.  The high ambient vapor pressure of the complex
(approximately 12 Torr at 23~C) enables extremely fast deposition
rates and hence, fast scan velocities during the serial deposition of
EC connections.  This precursor is also advantageous because thermal
dec...