Abstract:
An electrically conductive cement which when used to bond electrically conductive mating surfaces provides substantially stable conductivity characteristics under high humidity conditions; comprised of a carrier that provides a volumetric shrinkage of more than about 6.8% (vol.) and a conductive filler including agglomerates, particles, powders, flakes, coated nickel particles, and coated glass spheres, having size and surface characteristics that maintain stable electrical contact by forming a moisture resistant contact with an electrical component lead. The carrier having a volumetric shrinkage between the uncured and cured states of greater than about 6.8% (vol) appears to effect a compaction of the filler particles causing the particles to be forced into enhanced electrical contact with the surfaces to be connected and to provide a measure of compaction between the particles themselves to enhance particle-to-particle conduction. The shrinkage of the polymeric carrier during curing places the interior particles under compression with sufficient force to urge the particles into engagement with one another as well as to cause the particles to penetrate non-conductive oxides that may be present on a component lead.
Abstract:
An electrically conductive cement which when used to bond electrically conductive mating surfaces provides substantially stable conductivity characteristics under high humidity conditions; comprised of a carrier that provides a volumetric shrinkage of more than about 6.8% (vol.) and a conductive filler including agglomerates, particles, powders, flakes, coated nickel particles, and coated glass spheres, having size and surface characteristics that maintain stable electrical contact by forming a moisture resistant contact with an electrical component lead. The carrier having a volumetric shrinkage between the uncured and cured states of greater than about 6.8% (vol) appears to effect a compaction of the filler particles causing the particles to be forced into enhanced electrical contact with the surfaces to be connected and to provide a measure of compaction between the particles themselves to enhance particle-to-particle conduction. The shrinkage of the polymeric carrier during curing places the interior particles under compression with sufficient force to urge the particles into engagement with one another as well as to cause the particles to penetrate non-conductive oxides that may be present on a component lead.
Abstract:
A method of making a planar, subsurface electronic circuit having at least one electronic circuit component assembled therewith comprises forming three dimensional, essentially square channels (14) interspersed with lands within a dielectric material (12) on a substrate (10). The channels are then filled in one pass with a curable polymeric material (16) containing a conductive metal filler so that the upper surfaces of the circuit trace formed by this conductive material are at essentially the same level as the upper surface of the lands. Circuit components (20) are placed to engage the conductive material. The curable material is then cured after placing the electronic component(s).
Abstract:
A polymer lead frame is made from a flexible substrate (24) with flexible conductive traces (26). The generally square lead frame has diagonal cut-outs (42-48) partially extending from the corners towards the centre, as well as a central hole (62) that lies within a footprint of a die. The die (22) is bonded directly to the lead frame, preferably with anisotropic, electrically conductive adhesive (32). The die is placed with the lead frame in a fixture. A holding force is applied to secure the die and, if necessary, a curing force is applied during a cure cycle. The fixture allows transport of the assembly to a curing oven and allows application of the curing force. The die has contact pads characterised by a non-planar, non-bumplike surface with concavities having depths of at least one-seventh the diameter of conductive particles in the anisotropic conductive adhesive.
Abstract:
A method for producing a circuit board involves printing a U.V. curable ink onto a substrate in a desired circuit pattern and curing the ink by exposing it to a pulsed U.V. source or subjecting the circuit pattern prepared from a U.V. curable ink containing magnetite particles to a magnetic field to move the magnetite particles to the upper surface of the U.V. curable ink. Other embodiments include circuit boards made in accordance with these methods and the use of the U.V. curable ink as a shielding composition for enclosures housing electronic equipment.
Abstract:
A method for producing a circuit board involves printing a U.V. curable ink onto a substrate in a desired circuit pattern and curing the ink by exposing it to a pulsed U.V. source or subjecting the circuit pattern prepared from a U.V. curable ink containing magnetite particles to a magnetic field to move the magnetite particles to the upper surface of the U.V. curable ink. Other embodiments include circuit boards made in accordance with these methods and the use of the U.V. curable ink as a shielding composition for enclosures housing electronic equipment.
Abstract:
An electrically conductive cement which when used to bond electrically conductive mating surfaces provides substantially stable conductivity characteristics under high humidity conditions; comprised of a carrier that provides a volumetric shrinkage of more than about 6.8% (vol.) and a conductive filler including agglomerates, particles, powders, flakes, coated nickel particles, and coated glass spheres, having size and surface characteristics that maintain stable electrical contact by forming a moisture resistant contact with an electrical component lead. The carrier having a volumetric shrinkage between the uncured and cured states of greater than about 6.8% (vol) appears to effect a compaction of the filler particles causing the particles to be forced into enhanced electrical contact with the surfaces to be connected and to provide a measure of compaction between the particles themselves to enhance particle-to-particle conduction. The shrinkage of the polymeric carrier during curing places the interior particles under compression with sufficient force to urge the particles into engagement with one another as well as to cause the particles to penetrate non-conductive oxides that may be present on a component lead.
Abstract:
An electrically conductive cement which when used to bond electrically conductive mating surfaces provides substantially stable conductivity characteristics under high humidity conditions; comprised of a carrier that provides a volumetric shrinkage of more than about 6.8% (vol.) and a conductive filler including agglomerates, particles, powders, flakes, coated nickel particles, and coated glass spheres, having size and surface characteristics that maintain stable electrical contact by forming a moisture resistant contact with an electrical component lead. The carrier having a volumetric shrinkage between the uncured and cured states of greater than about 6.8% (vol) appears to effect a compaction of the filler particles causing the particles to be forced into enhanced electrical contact with the surfaces to be connected and to provide a measure of compaction between the particles themselves to enhance particle-to-particle conduction. The shrinkage of the polymeric carrier during curing places the interior particles under compression with sufficient force to urge the particles into engagement with one another as well as to cause the particles to penetrate non-conductive oxides that may be present on a component lead.
Abstract:
A polymer lead frame is made from a flexible substrate (24) with flexible conductive traces (26). The generally square lead frame has diagonal cut-outs (42-48) partially extending from the corners towards the centre, as well as a central hole (62) that lies within a footprint of a die. The die (22) is bonded directly to the lead frame, preferably with anisotropic, electrically conductive adhesive (32). The die is placed with the lead frame in a fixture. A holding force is applied to secure the die and, if necessary, a curing force is applied during a cure cycle. The fixture allows transport of the assembly to a curing oven and allows application of the curing force. The die has contact pads characterised by a non-planar, non-bumplike surface with concavities having depths of at least one-seventh the diameter of conductive particles in the anisotropic conductive adhesive.