Abstract:
The present invention provides a novel process and its required fluxable materials for building low-cost flip-chip interconnect structures. The novel process involves two fluxable materials, fluxable wafer-level compressive-flow underfill material (WLCFU) and fluxable tacky film, and applies these two materials on a wafer level. The two materials can provide sufficient fluxing capability during solder reflow and significant improvement of the fatigue life of the formed solder interconnects after fully cured.
Abstract:
The specification describes a cleaning process for electronic devices and assemblies such as printed wiring boards. In the cleaning process deterioration of a terpene based cleaning solution, as evidenced by yellowing, is prevented using a copper chelating additive.
Abstract:
An electronic device (12, 13) is substantially enclosed by a fluid encapsulant (17). The fluid encapsulant consists essentially of a silicone resin and a catalyst selected from the group consisting of platinum and tin. The silicone resin is selected from the group consisting of polydimethlysiloxane, polymethylphenylsiloxane, polydimethyldiphenylsiloxane, and mixtures thereof. Such silicone resins comprise molecules terminating in vinyl components and hydride components. The molar ratio of vinyl components to hydride components is maintained within the range of five to twenty. As will be explained more fully later, this ratio of vinyl components to hydride components assures that the resin will remain substantially a liquid even after cure, due to limited cross-linking or polymerization during the cure. The electronic device is contained within a container (16) having a sealed cover (18) for containing the liquid encapsulant during the operation of the electronic device.
Abstract:
A module, such as a terminal block (10), configured of a body (12) having an open end (20) and at least one window (24) spaced from the open end, is fixtured and sealed by way of a channel (28) comprised of a pair of parallel, spaced-apart, generally elastic walls (30,32) jointed by a bottom member (34). The walls (30,32) and the bottom member (34) run longitudinally a distance at least as long as the width of the terminal block (10) to allow the block to be received between, and to be held by, the walls. At least one protrusion extends out from a separate one of the walls (30,32) and the base member (34) for receipt in the window (24) in the terminal block to seal the same.
Abstract:
An electronic device encapsulant comprises polydimethyldiphenylmethylphenylsiloxane in which the mole ratio of the sum of the methyl-phenyl and diphenyl groups to the dimethyl groups is in the range of ten to forty percent. The normal bi-functional hydride terminations are replaced with tri-functional or tetra-functional hydride terminations.
Abstract:
The addition of a low viscosity (2 to 100 centipoise) polysiloxane such asolydimethylsiloxane to a two-part heat curable polysiloxane system substantially eliminates the formation of bubbles when such system is employed as a potting compound for encapsulating devices such as electronic devices.
Abstract:
A method of extending the shelf-life of an uncured silicone resin formulation which includes a primary amine therein comprises adding an acid to the formulation in a molar quantity approximately equal to the number of moles of primary amine present in the formulation, said acid being volatile at or below the curing temperature of the resin formulation.
Abstract:
In the manufacture of encapsulated hybrid circuits from a substrate having a plurality of such circuits contained thereon, individual devices are first mounted on the circuit, encapsulant having a yield point stress and viscosity so as not to creep or flow is applied around the periphery of each circuit on the substrate so as to form a wall or dam around each such circuit except for the bonding pads for external connection of each circuit, a second encapsulant is then flow coated over the circuit and devices contained thereon within the previously formed wall such that the second encapsulant is retained within the wall. The encapsulants are then cured or dried and the individual encapsulated circuit can then be further processed such as by separating the individual circuits on the substrate and applying external connectors to the bonding pads.
Abstract:
A method of removing a cured epoxy from a surface is disclosed. The method comprises treating at least the epoxy with a suitable swelling agent to swell the epoxy. The swelled epoxy is then treated with an oxidizing agent to oxidize the swelled epoxy. The oxidized epoxy is then treated with an etchant comprising sulfuric acid to remove the epoxy from the surface.
Abstract:
An electrical condition monitoring method utilizes measurement of electrical resistivity of an age sensor made of a conductive matrix or composite disposed in a polymeric structure such as an electrical cable. The conductive matrix comprises a base polymer and conductive filler. The method includes communicating the resistivity to a measuring instrument and correlating resistivity of the conductive matrix of the polymeric structure with resistivity of an accelerated-aged conductive composite.