International Business Machines Corporation

Herman S Hoffman

Richard W Noth

John Gow, 3rd

Robert T Howard, Jr

Earl Stephans

A compliant lead for electromechanically surface mounting an integrated circuit chip package to a substrate. The compliant lead extends from the package and includes at least two regions of different lead thickness. In a first region, a standard lead thickness is employed to ensure the applicability of existing package fabrication techniques. A second region, having a reduced thickness, then extends from the first region and is predefined to encompass an area of the lead expected to undergo greatest stress during thermal cycling. Compliancy is further guaranteed by providing a solder dam within the region of reduced thickness to limit wicking of solder when the package is solder mounted to the substrate. Lead frame fabrication is also discussed.

Compliant lead for surface mounting a chip package to a substrate

A method of treating ceramic materials used in semiconductor packaging applications to reduce their emission of alpha particles. Ceramic materials made of aluminum oxide particles bonded together with a siliceous binding material, are etched to remove the siliceous material from a surface portion of the ceramic. Since the typically used siliceous materials have alpha particle emitting elements in them by removing this siliceous material from a surface layer of the ceramic material the sources of alpha particles which are most likely to cause failures in electronic devices are removed. Alpha particle sources deeper in the ceramic pose a far lesser threat to the device because these relatively low energy, high volume particles suffer a substantial attenuation as they pass through aluminum oxide particles.

Surface treatment for ceramics to eliminate alpha particle emitting

A method for laser trimming of resistors which includes sputter depositing or vaporizing resistor material in a limited area but the resistor geometry and trimming location is designed to achieve a maximum resistor trimming range with a minimum substrate area occupied by the resistor. A cermet resistor is fabricated on a metallized ceramic substrate with the resistor having a low length to width ratio. A laser cut is used to provide resistor values greater than 250 ohms and up to 16000 ohms.

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Milton, VT, United States of America

Herman S Hoffman