International Business Machines Corporation

Robert D Topa

Sung Kwon Kang

Timothy C Reiley

Michael J Palmer

Raymond Thomas Galasco

Lawrence P Lehman

Roy H Magnuson

Madhav Datta

Robin A Susko

David W Dranchak

Francis Joseph Downes, Jr

Jaynal Abedin Molla

George J Saxenmeyer, Jr

Fletcher W Chapin

Raymond A Busacco

Timothy P Henning

An arrangement and method for the degassing small high-aspect ratio drilled holes or vias which are present in panels such as printed circuit boards prior to wet chemical processing, including copper plating of the vias, in order to remove any air or gas bubbles from the vias tending to inhibit the reliable plating thereof. This is carried out through the utilization of an ultrasonic prewetting in a liquid bath preceding cleaning for the electroless plating process, thereby enabling all of the vias or holes to be degassed; in effect, having air removed and the vias or holes filled with liquid; thereby allowing subsequent process cleansing solutions to easily flow into the respective holes or vias in order to facilitate the electroless copper plating process.

Arrangement and method for degassing small-high aspect ratio drilled holes prior to wet chemical processing

A method of removing a metal skin from a through-hole surface of a copper-Invar-copper (CIC) laminate without causing differential etchback of the laminate. The metal skin includes debris deposited on the through-hole surface as the through hole is being formed by laser or mechanical drilling of a substrate that includes the laminate as an inner plane. Removing the metal skin combines electrochemical polishing (ECP) with ultrasonics. ECP dissolves the metal skin in an acid solution, while ultrasonics agitates and circulates the acid solution to sweep the metal skin out of the through hole. ECP is activated when a pulse power supply is turned on and generates a periodic voltage pulse from a pulse power supply whose positive terminal is coupled to the laminate and whose negative terminal is coupled to a conductive cathode. After the metal skin is removed, the laminate is differentially etched such that the copper is etched at a faster rate than the Invar. To prevent the differential etching, a copper layer is formed on a surface of the substrate with an electrical resistance R,between the copper layer and the positive terminal of the pulse power supply. Additionally, an electrical resistance R,is formed between the laminate and the positive terminal of the pulse power supply. Adjustment of R,and R,controls the relative etch rates of the copper and the Invar.

Removal of metal skin from a copper-Invar-copper laminate

A method for cleaning a copper-INVAR-copper laminate in an acid solution without inducing a galvanic etching of the INVAR. An initial step of the method forms a circuit element that includes a power supply, the laminate electrically coupled to a negative terminal of the power supply, and a conductive anode electrically coupled to a positive terminal of the power supply. The conductive anode may include a conductive material, such as titanium, that is preferably inert to an acid solution into which the laminate will be subsequently immersed. After turning on the power supply to a voltage between about 1 volts and about 10 volts, the laminate and conductive anode are immersed in the acid solution, so as to form a closed circuit with a voltage bias across acid copper-INVAR-copper interfaces. The voltage bias prevents galvanic action from occurring and therefore protects against galvanic etching of the INVAR. After the laminate has been cleaned by the acid solution, the laminate is removed from the acid solution and the power supply is turned off. The laminate may also exist as an internal layer of a dielectric substrate, wherein the substrate is immersed in the acid solution, and wherein a through hole passing through the substrate passes through the copper-INVAR-copper laminate.

Biased acid cleaning of a copper-invar-copper laminate

A contact member for thermocompression bonding in integrated circuit packaging has on a conductor end a uniform texture deformable layer with a hardness value in the range of that of soft gold which is approximately 90 on the Knoop scale and with a rough surface morphology having ridges with approximately 1 micrometer modulation frequency and a depth between ridges of from 1/4 to 1/2 that of the average integrated circuit pad. The deformable layer is produced by plating gold in a strong electronegative plating bath within a range of 0.03 to 0.05 mA/sq.mm. current density. Plating apparatus, for plating different areas, with different electronegative conditions, with separate independently powered anodes, is provided.

Thermocompression bonding in integrated circuit packaging

A method of forming conductive end portions on a flexible circuit member having a dielectric layer (e.g., polyimide) with at least one conductive element (e.g., copper) thereon. The method comprises the steps of forming (e.g., punching) an opening through both dielectric and conductive element, providing (e.g., additive plating) an electrically conducting layer on the opening's internal surface, providing (e.g., electroplating) a plurality of dendritic elements on the conducting layer's surface, and thereafter removing (e.g., punching) a portion of the dielectric and conductive element such that the formed dendritic elements (e.g., palladium) project from the flexible circuit's conductive ends.

Method of forming a conductive end portion on a flexible circuit member

A contact member for thermocompression bonding in integrated circuit packaging has on a conductor end a uniform texture deformable layer with a hardness value in the range of that of soft gold which is approximately 90 on the Knoop scale and with a rough surface morphology having ridges with approximately 1 micrometer modulation frequency and a depth between ridges of from 1/4 to 1/2 that of the average integrated circuit pad. The deformable layer is produced by plating gold in a strong electronegative plating bath within a range of 0.03 to 0.05 mA/sq.cm. current density. Plating apparatus, for plating different areas, with different electronegative conditions, with separatre independently powered anodes, is provided.

Lead frame plating apparatus for thermocompression bonding

A contact member for thermocompression bonding in integrated circuit packaging has on a conductor end a uniform texture deformable layer with a hardness value in the range of that of soft gold which is approximately 90 on the Knoop scale and with a rough surface morphology having ridges with approximately 1 micrometer modulation frequency and a depth between ridges of from 1/4 to 1/2 that of the average integrated circuit pad. The deformable layer is produced by plating gold in a strong electronegative plating bath within a range of 0.03 to 0.05 mA/sq.cm. current density. Plating apparatus, for plating different areas, with different electronegative conditions, with separate independently powered anodes, is provided.

A palladium-nickel alloy is deposited onto a substrate by electroplating from a plating bath containing palladosammine chloride, nickel ion source, ammonium sulfate, ammonium chloride, and sufficient ammonium hydroxide to provide a pH of about 7.0 to about 8.3 at a temperature of about 60.degree. F. to about 90.degree. F.

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Binghamton, NY, United States of America

Robert D Topa