International Business Machines Corporation

Kathleen L Covert

John M Lauffer

David Noel Light

Peter A Moschak

Joseph Paul Kuczynski

Voya Rista Markovich

Richard A Schumacher

Elizabeth F Foster

Stephen L Tisdale

Perminder S Bindra

Richard William Malek

Julio M Alvarado

Charles C Emmons

Charyl L Tytran

Jennette E Kingsley

The present invention is a persulfate microetchant composition especially useful for removing impurities from copper surfaces during fabrication of microelectronic packages. The microetchant formulation is characterized by its ability to selectively clean copper in the presence of nickel, nickel-phosphorous and noble metal alloys therefrom. Furthermore, no deleterious galvanic etching occurs in this microetchant-substrate system so that substantially no undercutting of the copper occurs. The combination of high selectivity and no undercutting allows for a simplification of the microelectronic fabrication process and significant improvements in the design features of the microelectronic package, in particular higher density circuits. The persulfate microetchant composition is stabilized with acid and phosphate salts to provide a process that is stable, fast acting, environmentally acceptable, has high capacity, and can be performed at room temperature. A preferred etchant composition is 100 gm/liter sodium persulfate, 3 volume % phosphoric acid and 0.058 molar sodium phosphate dibasic.

Copper cleaning compositions, processes and products derived therefrom

The present invention is a persulfate etchant composition especially useful for dissolving copper during fabrication of microelectronic packages. The etchant is characterized by its ability to selectively etch copper in the presence of nickel, nickel-phosphorous and noble metal alloys therefrom. Furthermore, no deleterious galvanic etching occurs in this etchant-substrate system so that substantially no undercutting of the copper occurs. The combination of high selectivity and no undercutting allows for a simplification of the microelectronic fabrication process and significant improvements in the design features of the microelectronic package, in particular higher density circuits. The persulfate etchant composition is stabilized with acid and phosphate salts to provide a process that is stable, fast acting, environmentally acceptable, has high capacity, and can be performed at room temperature. A preferred etchant composition is 230 gm/liter sodium persulfate, 3 volume % phosphoric acid and 0.058 molar sodium phosphate dibasic.

Copper etching compositions and products derived therefrom

A photocopolymerizable composition for backsealing a ceramic carrier and process for using the composition is disclosed. The composition comprises: a liquid, multifunctional, bisphenol based epoxy; a liquid, multifunctional hydroxyl containing organic material; a complex onium salt photoinitiator; and, a complex cupric salt initiator. The composition utilizes a strong Bronstead acid for additional deep curing created by iodonium salt thermolysis.

Dual cure epoxy backseal formulation

Disclosed is a method of fabricating a microelectronic package, especially a microelectronic package having copper circuitization on a dielectric substrate. The method includes depositing copper on opposite surfaces of the package, and then depositing resist atop the copper. The resist is patterned, e.g., by photolithography or screening so that intended circuitization traces are covered by the resist. The exposed copper is etched, and the resist is stripped off of the unexposed copper. The process is characterized in that the etchant is upwardly sprayed onto a downwardly facing first surface of the package for half of the etching cycle, and then the package is rotated so that etchant is upwardly sprayed onto the downwardly facing second surface of the package.

Etching method for increased circuitized line width and uniformity

A strippable thin film of Cu is applied above the surface features of a microelectronic circuit package to protect the features during mechanical working, for example drilling, the panel. The thin film is then stripped off of the panel. The thin film may be stripped off of the panel either prior to or after circuitization.

Method of external circuitization of a circuit panel

Spent ferric chloride etching compositions are regenerated by electrolysis which includes introducing spent ferric chloride etching composition containing total iron content substantially equal to the original total iron content of fresh etching composition into the anode compartment of an electrolysis cell that contains an anode compartment, a cathode compartment, and an anion-exchange membrane separating the compartments, and applying voltage of +0.6 to +1.5 volts versus a saturated calomel electrode to the anode.

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Kirkwood, NY, United States of America

Kathleen L Covert