Olin Corporation

Advanced Technology Interconnect Incorporated

Arvind Parthasarathi

Deepak Mahulikar

Ned W Polan

Julius C Fister

Raymond J Smialek

Satish K Jalota

Szuchain F Chen

Andrew J Brock

Jeffrey S Braden

Dexin Liang

German J Ramirez

Efraim Sagiv

Michael A Holmes

Jeffrey M Schlater

Derek E Tyler

Joseph Winter

Igor V Kadija

Paul R Hoffman

William L Brenneman

Dennis R Brauer

George A Brathwaite

Peter E Sevier

Christopher P Laurello

Dawit Solomon

Jeffrey Schlater

Christoper P Laurello

Lynn Strauman

A method of introducing an anti-tarnish agent into the matrix of a tin coating to reduce oxidation and/or yellowing of the tin coating. The agent is preferably zinc, indium or phosphorous and can be deposited in a molten form to alloy with the existing tin coating. Alternatively, the existing tin coating may be exposed to a chemical bath including the agent and later heated to reflow the tin coating and agent thereby incorporating the agent into the matrix of the tin coating.

Tin coatings incorporating selected elemental additions to reduce

An electrical conductor has a copper base substrate coated with a tin base coating layer. To inhibit the formation of a copper/tin intermetallic and the resultant depletion of the free, unreacted, tin utilized as an oxidation and corrosion barrier, a barrier is interposed between the substrate and the coating. In a first embodiment, the barrier is formed from multiple constituent layers, at least one of which is copper. The thickness ('y') of the copper layer is dependent on the anticipated service temperature and satisfies the equation y=(-1.52+0.0871x+0.00859 t).+-.50% where t=anticipated time at the service temperature, x=anticipated service temperature (Celsius), and y=the thickness of the copper layer in microinches. In a second embodiment, the barrier layer is formed from one or more constituent layers, at least one of which is iron or iron base.

Multi-layer diffusion barrier for a tin coated electrical connector

There is provided a leadframe assembly for encapsulation in a polymer resin which prevents post-assembly fracture or swelling of the resin. The leadframe is coated with an adhesion enhancing layer that increases the shear stress required for delamination to in excess of about 3.4 MPa. In combination with this adhesion enhancing layer is a compliant die attach adhesive bonding an integrated circuit device to a central die attach paddle. This compliant die attach adhesive has a compliancy factor, E.multidot.a of less than 1.5 MPa/.degree.C. and a thickness of from about 0.01 mm to about 0.08 mm.

Semiconductor package with molded plastic body

Anodizable components for electronic packaging applications, such as substrates for printed circuit boards or ball grid array electronic packages, having conductive circuitry formed on an electrically non-conductive anodic film. To inhibit the formation of electrically conductive precipitates in the anodic film that can form an electrical short circuit between the circuit traces and the metallic core of the component, the metallic core is formed from an anodizable alloy having below thresholds of precipitate forming constituents. Such precipitate forming constituents include iron, silicon and manganese.

Aluminum alloys for electronic components

A method for improving adhesion from a leadframe to a metallic wire is disclosed including using a laser beam to remove selected areas of an package adhesion enhancing layer to expose a layer on the leadframe which has a higher adhesion to metallic wires. The package adhesion enhancing layer is from the group consisting essentially of aluminum oxide, anti-tarnish finishes, and dielectrics. The exposed layer on the leadframe is selected from the group consisting essentially of silver, nickel, palladium.

Enhanced wire-bondable leadframe

There is provided an anodizable aluminum substrate having an increased breakdown voltage. The increase in breakdown voltage is achieved by selecting an appropriate aluminum alloy and appropriate processing parameters. Sealing the anodic film increases the breakdown voltage by decreasing corrosion. A preferred sealant is an epoxy cresol novolac having a low room temperature viscosity that cures to a highly cross-linked polymer.

Anodized aluminum substrate having increased breakdown voltage

An electronic package having improved thermal performance. In the case of a plastic package, the inner ends of the leads of the lead frame are attached to a heat slug by a high thermal conductivity material such as solder or a polymeric material. In the case of a metal package, the inner ends of the leads of the leadframe are attached to the metal base component by a high thermal conductivity material.

Electronic package with improved thermal properties

There is provided a metallic component for an electronic package. The component is coated with an electrically non-conductive layer and has a plurality of conductive circuit traces are formed on a surface. The circuit traces are soldered directly to the input/output pads of an integrated circuit device and to a second plurality of circuit traces. The component may include a heat sink to enhance dissipation of heat from an encapsulated integrated circuit device.

Components for housing an integrated circuit device

There is provided a composite material particularly suited for electrical and electronic applications having a metallic core with a desired surface finish. An acicular superficial coating layer having an apparent thickness of less than 275 angstroms is adjacent to at least a portion of the metallic core. The superficial coating layer is removable from the metallic core without appreciable change to the metallic core surface finish.

Superficial coating layer having acicular structures for electrical

There is disclosed a leadframe for electrically interconnecting a semiconductor device to external circuitry. The leadframe has an electrically conductive substrate that is coated with an oxidation resistant external layer. An intervening layer is disposed between a portion of the substrate and the external layer. The intervening layer is absent from the outer lead ends of the leadframe. Subsequent removal of the external layer from the outer lead ends enables a solder to directly contact the leadframe substrate.

Leadframe having exposed, solderable outer lead ends

There is disclosed a process for the assembly of an electronic package in which the outer lead ends of a leadframe are solderable to external circuitry without the necessity of a tin or solder coat. An oxidation resistant layer is deposited on the leadframe prior to package assembly. The oxidation resistant layer is removed prior to outer lead soldering providing a clean, oxide free metallic surface for soldering.

Method for the assembly of an electronic package

There is disclosed an aqueous chemical solution that consists essentially of zinc ions, a source of hydroxides, and silicon ions. The ratio of silicon to zinc (Si:Zn) is, by weight from about 1:5 to about 1:250. Within the ratio range, the silicon ions inhibit precipitation of zinc from the chemical solution. This is particularly useful when the chemical solution is an electrolyte for the deposition of zinc or a zinc containing compound onto a metallic structure where a critical zinc content must be maintained to impart adequate adhesion of a coated substrate to a polymer adhesive.

Aqueous zinc solution resistant to precipitation

There is provided a lead frame with enhanced adhesion to a polymer resin. The lead frame is coated with a thin layer of containing chromium, zinc or a mixture of chromium and zinc. A mixture of chromium and zinc with the zinc-to-chromium ratio in excess of about 4:1 is most preferred. The coated lead frames exhibit improved adhesion to a polymeric resin.

Lead frames with improved adhesion to a polymer

There is provided a lead frame with enhanced adhesion to a polymer resin. The lead frame is coated with a thin layer of containing a mixture of chromium and zinc. A mixture of chromium and zinc with the zinc-to-chromium ratio in excess of about 4:1 is most preferred. The coated lead frames exhibit improved adhesion to a polymeric resin.

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North Branford, CT, United States of America

Arvind Parthasarathi