Hughes Aircraft Company

Other

Raymond L Brown

William A Vitriol

Richard P Himmel

Robert F McClanahan

Hal D Smith

Andrew A Shapiro

Ramona G Pond

Gerald B Smith

Clifford L Shock, Jr

A plumb bob system for allowing an individual to easily utilize a plumb bob in determining whether a wall is plumb. The plumb bob system includes a pole, an engaging structure attached to an upper end of the pole, a pulley rotatably positioned within the engaging structure, a spool containing a length of string passing about the pulley, and a plumb bob attached to the end of the string opposite of the spool. The engaging structure is comprised of a first member and a second member having a first edge and a second edge respectively. The first edge and second edge have a common length of radius from a center point of the pulley to provide an average upper distance (Z) of the string from the wall. The center of the plumb bob has a distance from the lower portion of the wall (X) that is compared to the upper distance (Z). If the upper distance (Z) and the lower distance (X) are equal then the wall is being constructed plumb and no modifications are required in the construction of the wall. If the upper distance (Z) and the lower distance (X) are different then the builders will have to adjust the building of the wall accordingly to avoid building the wall in a non-vertical fashion.

Plumb bob system

The present invention provides a method and apparatus for metallizing vias in co-fired ceramic green tape. A vacuum operated pick and place anvil comprising a porous block is used to pick up conductor balls from a bed. Air pressure is used to create a vacuum which pulls the conductor balls to the porous block. A stencil having openings is placed on a contact surface of the anvil, thereby permitting only one conductor ball to attach to each opening in the stencil. With the conductor balls attached to the anvil, the anvil is lowered onto the green tape. Next the anvil pushes the conductor balls into the tape until the conductor balls break through the opposite side of the tape. The anvil is retracted leaving the conductor balls lodged in the tape. It is possible to provide a green tape with pre-formed vias so that forcing the conductor balls into the tape is a simpler task. The locations of the openings in the stencil determines the location of the vias or must correspond to the vias in a tape having pre-formed vias. If the conductor balls protrude from any surface of the tape, the anvil or similar device can be used to flatten the protrusion. In alternative embodiments, the present invention conductor balls can be substituted with a material having a high thermal conductivity, or a high dielectric constant, or to include ferrite.

Green ceramic via metallization technique

The present invention provides a method for metallizing vias in co-fired ceramic green tape. A vacuum operated pick and place anvil comprising a porous block is used to pick up conductor balls from a bed. Air pressure is used to create a vacuum which pulls the conductor balls to the porous block. A stencil having openings is placed on a contact surface of the anvil, thereby permitting only one conductor ball to attach to each opening in the stencil. With the conductor balls attached to the anvil, the anvil is lowered onto the green tape. Next the anvil pushes the conductor balls into the tape until the conductor balls break through the opposite side of the tape. The anvil is retracted leaving the conductor balls lodged in the tape. It is possible to provide a green tape with pre-formed vias so that forcing the conductor balls into the tape is a simpler task. The locations of the openings in the stencil determines the location of the vias or must correspond to the vias in a tape having pre-formed vias. If the conductor balls protrude from any surface of the tape, the anvil or similar device can be used to flatten the protrusion.

Discrete solder preforms (28, 14a, 14b, 14c) are quickly and accurately placed on substrates (10) to be soldered by means of a foil sheet (24) apertured (26) with the pattern of preform placement. The foil sheet has a vacuum drawn through its apertures, and a number of discrete solder preforms are randomly projected from a vibratory membrane (38) up against the foil to be attached to the foil at each of its apertures. Then the foil sheet with its vacuum attached solder preforms (28, 14a, 14b, 14c) is moved into registration with the flux pattern (12a, 12b, 12c) pre-printed on the substrate (10), and all of the vacuum attached preforms are simultaneously positioned down upon the flux areas of the substrate where they remain when the vacuum is released. Planarity of the thin foil is maintained by a flat somewhat rigid but porous backing member (32) secured to the foil.

Component and solder preform placement device and method of placement

Via resistor structures in a hybrid multilayer circuit having a plurality of insulating layers. One via resistor structure includes a plurality of resistive via fills in vias in respective adjacent insulating layers, a plurality of conductive elements for electrically contacting predetermined tops and bottoms of the resistive via fills, and conductive via fills for providing external electrical connection to selected ones of the conductive elements at locations on the outside the unitized multilayer circuit structure. A further via resistor structure includes a resistive via fill formed in a via in one of the insulating layers, and one or more thermally conductive via fills for thermally conducting heat from said resistive via fill to the outside of the unitized multilayer circuit structure. Another via resistor structure comprises ratioed via resistors comprising a plurality of resistive via fills formed in respective vias in one of the insulating layers, said vias having substantially the same thickness and having respective cross-sectional areas selected to provide resistance values having predetermined ratios.

Via resistors within-multi-layer, 3 dimensional structures substrates

A high current feedthrough package comprising a plurality of alternating rings respectively comprising a thermally conductive material and an electrically conductive material. The thermally conductive rings comprise a thermally conductive ceramic material such as aluminum nitride, while the electrically conductive rings comprise a material such as molybdenum, or one of its alloys, for example. The package is thus comprised of alternating rings or laminations of aluminum nitride and molybdenum, for example, that are stacked or layered to form a wall. The layered wall is brazed in a single step onto a base. The molybdenum rings act as high current feedthroughs and comprise tabs on the inner and outer perimeter which are available for interconnection to devices disposed within the enclosure and to external circuits. The aluminum nitride rings provide electrical isolation between the feed-through rings. The high thermal conductivity of the molybdenum and aluminum nitride provides for excellent thermal dissipation from the package. Forced convective cooling may also be used to further increase the current carrying capability of the package. Methods of fabricating the package are also disclosed.

High current feedthrough package

A technique is disclosed for trimming resistors and other passive circuit components buried in hybrid multilayer circuit structures. For example, resistors (13) are formed between two dielectric layers (11, 19) of a hybrid multilayer circuit structure (10). The multilayer circuit structure with the buried resistors is appropriately processed to provide a fired multilayer circuit structure. Trimming of the buried resistors is accomplished with a laser beam that cuts through dielectric material of the fired circuit structure to selectively remove part of the resistive material of the buried resistors. The values of the buried resistors may be tested with conductive elements (15, 17) that are conductively coupled to the buried resistors. The disclosed technique also contemplates the trimming of other buried passive circuit components such as capacitors, and further contemplates the use of other trimming methods such as abrasive, air jet, or water jet trimming.

Trimming passive components buried in multilayer structures

We disclose a process for manufacturing multilayer circuit boards which includes providing a conductive, or an insulating substrate with a conductive pattern thereon, and then transferring and firing a glass-ceramic tape layer to the surface of the substrate. This tape layer provides both electrical isolation between the substrate and electrical conductors or electronic components which are subsequently bonded to or mounted on the top surface of the glass-ceramic tape layer. By providing vertical electrical conductors by means of vias in the tape layer prior to firing the tape layer directly on the substrate, good X and Y lateral dimensionally stability of the tape material is maintained. In addition, a high quality thick film glass-ceramic electrical interconnect structure is achieved at a relatively low manufacturing cost.

Growing community of inventors

Fountain Valley, CA, United States of America

Raymond L Brown