E.i. Dupont De Nemours and Company

Vincent P Siuta

Paul C Donohue

Joel Slutsky

A method for making a thick film/solder joint comprising the sequential steps of:

Method for making thick film/solder joints

Thick film electronic compositions comprising finely divided particles of electrically functional material and a PbO-compatible inorganic binder dispersed in an organic medium in which 0.1 to 10.0% wt. lead nitrate is coated on the surface of at least one of the solide components.

Thick film electronic materials

A fritless copper conductor composition suitable for overprinting on copper consisting essentially of (a) 10-50% wt. finely divided copper particles, (b) 90-50% wt. coarse copper particles, (c) 0.2-2% wt. reducible heavy metal oxide, (d) 0-1.0% refractory metal and (e) 0-5.0% of a high surface area noble metal, all the particles being dispersed in an organic medium.

Copper conductor compositions

Particles of Cu-containing metal having a particle size of 0.5-20 .mu.m in largest dimension bearing a thin, substantially continuous coating of at least one metal oxide having a free energy of formation more negative than -98 kcal/mole and method of making them. The metal oxide-coated particles have improved sintering and shrinking properties which closely match those of green ceramic tape.

Metal oxide-coated copper powder

A copper-containing thick film conductor composition comprising a mixture of finely divided particles of (a) a conductive material containing copper metal, (b) inorganic binder and (c) 0.2-5% wt. of a noncuprous metal selected from the group consisting of tungsten, molybdenum, rhenium and alloys and mixtures thereof all dispersed in organic medium. The metal particles must be within certain narrow ranges of particle size.

Thick film conductor compositions

Thick film conductor compositions comprising finely divided particles of copper oxide-coated copper and low softening point inorganic binder dispersed in a low-resin organic medium. Additional copper oxide is incorporated into the composition by either direct addition or by inclusion in the inorganic binder.

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Cherry Hill, NJ, United States of America

Vincent P Siuta