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Browse Prior Art Database

Solder Powder Surface Treatment for Solder Paste

IP.com Disclosure Number: IPCOM000119413D
Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 1 page(s) / 46K

Publishing Venue

IBM

Related People

Chopra, MA: AUTHOR [+3]

Abstract

Disclosed is a process for modifying solder powder prior to using the powder to make solder paste. Solder powder (e.g., Sn-Pb eutectic) is modified by reacting the powder with a coupling agent in order to alter the chemistry at the surface of the powder. A variety of organotitanates, organozirconates and organosilanes may be utilized for the surface modification process. Some specific examples include isopropyl tri(dioctyl)pyrophosphato titanate and tetra(2,2-diallyloxymethyl)butyl, di(tridecyl)phosphito zirconate. The surface modification or "capping" process is accomplished by refluxing dry solder powder with a nonaqueous solution of the coupling agent. The result is substitution of hydroxyl (OH) functionalities on the solder surface with the appropriate titanate, zirconate or silane esther (Fig. 1).

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Solder Powder Surface Treatment for Solder Paste

      Disclosed is a process for modifying solder powder prior to
using the powder to make solder paste.  Solder powder (e.g., Sn-Pb
eutectic) is modified by reacting the powder with a coupling agent in
order to alter the chemistry at the surface of the powder.  A variety
of organotitanates, organozirconates and organosilanes may be
utilized for the surface modification process.  Some specific
examples include isopropyl tri(dioctyl)pyrophosphato titanate and
tetra(2,2-diallyloxymethyl)butyl, di(tridecyl)phosphito zirconate.
The surface modification or "capping" process is accomplished by
refluxing dry solder powder with a nonaqueous solution of the
coupling agent.  The result is substitution of hydroxyl (OH)
functionalities on the solder surface with the appropriate titanate,
zirconate or silane esther (Fig. 1).

      There are two primary advantages for modifying solder powder.
First, "capping" the surface makes the solder powder more corrosion
resistant.  The flux, which is combined with the solder powder to
make solder paste, contains activator components which may actively
corrode the solder powder at room temperature.  This decreases the
usable shelf life of the solder paste and often limits the choice of
activators to those which are less active.  The second advantage is
enhanced dispersion of the solder powder in the paste.  The
dispersion process is mechanical, and the ultimate paste quality is,
in pa...