International Business Machines Corporation

Kailash C Joshi

Joseph Hromek

Ronald Neil Spaight

George C Phillips, Jr

Octavio I Chirino

Plural groups of one or more magnetic domain devices each are mounted in an array on the circuitized surface of a common substrate. A rectangular pattern of slots is provided in the substrate around each group. Each group is encompassed through the slots by the turns of the inner and outer orthogonal solenoids of its own exlusive rotational magnetic field drive system and permanent magnet bias field closed structure. Each device has a pattern of I/O pads located on its undersurface which are bonded to a corresponding pattern of terminal pads which are part of the circuitized surface of the substrate. The interconnecting signal lines to the terminal pads of the substrate pass through one or more of the four intersection corners formed between the slots of the rectangular pattern. Preferably, the substrate also accommodates integrated circuit modules and/or other components mounted thereon which are associated with the drive, sense and other support circuitry for the magnetic domain devices.

Magnetic domain device modular assembly

A plurality of metal studs are plated on a chip carrier surface in a pattern to match a terminal metal footprint on a chip to be joined. The studs are of sufficient height to permit flux cleaning, if necessary. After the studs are in place, the chip is aligned with the carrier and attached thereto, the chip pads containing a small amount of solder to provide the connecting joints. The carrier and chip are made of materials having nearly equal thermal expansion characteristics.

Studded chip attachment process

Heat is removed from the silicon devices in an integrated circuit package by means of a stud which is slidably mounted in a cap enclosing the integrated circuit device. A low melt solder is used to join the stud to the cap and the same solder is also deposited on the stud tip, which will subsequently contact the integrated circuit device in the package. After the integrated circuit, substrate and cap are assembled and sealed, the assembly is heated to melt the low melt solder so that the stud slides down and makes contact with the integrated circuit device. A controlled pressure can be applied to the stud if sliding does not occur. Thereafter, the assembly is allowed to cool. Upon cooling, a submicron gap exists between the solder on the tip of the stud and the device providing electrical isolation, but not significantly degrading the thermal path between the device and the ambient atmosphere.

Studded heat exchanger for integrated circuit package

This is a microelectronic multilayer circuit structure having circuit compatibility encapsulated within the circuit package including conductive electrical interconnection means formed by uniquely metallizing the 'via' and/or blind interconnection holes within the circuit package. The assembly process provides means of uniformly metallizing the interlayer connecting holes.

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Endwell, NY, United States of America

Kailash C Joshi