Abstract: A method for producing an electronic circuit assembly (e.g., a circuit board) from an etched tri-metal-layer structure which provides air bridge crossovers and specially designed bumps etched from a middle layer of the tri-metal-layer structure. The bumps are formed at particular circuit locations in order to provide interconnects for (1) heavy wirebonding, (2) fine wirebonding, or (3) direct chip attachment; or, to provide (4) lifters for assuring a minimum solder joint standoff height or (5) barriers for retarding solder joint crack propagation.

Abstract: There is disclosed herein a printed circuit board (PCB) having improved resistance against solder bridging and component decentering/tombstoning. The printed circuit board (PCB) includes a substrate 10 having a top surface 12; at least two mounting pads 14 disposed on the top surface in matched relation with terminations 26 of an electronic component 24; and a solder mask 16 disposed on the top surface and having at least two apertures 18 therethrough, wherein each aperture generally conforms in shape with and is arranged about a respective one of the mounting pads 14. Each aperture 18 has at least one inner aperture edge 22i generally within a projected footprint F of the electronic component and at least one outer aperture edge 22o generally outside the footprint F. Each aperture 18 includes a notch 20 in one or more of the at least one outer aperture edge 22o, wherein each notch 20 extends generally outward from its respective mounting pad 14.

Abstract: An interposer 10 for electrically coupling a semiconductor die 50 to a substrate 70, comprising: an interposer body 12 made of a dielectric material and having a contact surface 14 and an opposed bonding surface 16; a plurality of contact pads 18 arranged about the periphery of the contact surface 14; a plurality of bonding pads 20 arranged across generally the entire area of the bonding surface 16; and a plurality of electrically conductive conduits 22 disposed generally within the interposer body, such that each conduit 22 connects a respective one of the contact pads 18 with a respective one of the bonding pads 20.

Abstract: An electronic circuit assembly having anti-tombstoning solder joints, including: a substrate 10 having at least one mounting pad 20 thereon; an SMD 30 having at least one termination 40; and at least one solder joint 50 connecting each termination 40 to its respective mounting pad 20. Each solder joint 50 is convex in shape, having a continuous and substantially circular arcuate outer profile 60 and covering substantially all of the mounting pad 20 and substantially all of a top portion 42 of each termination 40. Each mounting pad 20 has a predetermined length lp and each solder joint has a predetermined volume of solder selected such that a positive net anti-tombstoning moment is exerted upon the SMD 30 when at least one solder joint 50 is in a molten state.

Abstract: A method and article for attaching an electronic component, such as a semiconductor die, to a substrate includes applying a relatively low-melting-temperature solder preform to the substrate; and applying a bead of a curable bonding material to the substrate around the periphery of the solder preform in an amount sufficient to substantially contain the solder material and bridge the gap between the die and the substrate upon a subsequent collapse of the solder preform along its thickness dimension. After placing the die atop the solder preform so as to at least partially overlie the bonding material, the method includes heating the solder preform and the bonding material so as to reflow the solder, whereupon the solder preform collapses to allow the bonding material to engage the underside of the die, and to subsequently cure the bonding material.

Abstract: There is disclosed herein an electronic circuit assembly, such as a printed circuit board, having solder resist windows with one or more enlarged solder resist pullback zones, thereby facilitating solder paste overprinting.

Abstract: A product for attaching an electronic component, such as a semiconductor die, to a substrate includes a relatively low-melting-temperature solder preform applied to the substrate; and a bead of a curable bonding material applied to the substrate around the periphery of the solder preform in an amount sufficient to substantially contain the solder material and bridge the gap between the die and the substrate upon a subsequent collapse of the solder preform along its thickness dimension.

Abstract: There is disclosed herein a printed circuit board (PCB) having enhanced mounting pads useful for overprinting solder paste and for repair of the solder joints. The PCB comprises: a dielectric substrate 10 having at least one mounting pad 20 thereon, wherein each mounting pad is arranged in matched relation with a respective termination 32 of an electronic component 30. Each mounting pad 20 includes a main body portion 24 and one or more fingerlike extensions 26 extending outward from the main body portion and away from a projected footprint 34 of the electronic component.

Abstract: A pneumatic actuator for use with a pump for dispensing molten solder on a surface, such as an integrated circuit substrate. The pump has a reservoir for containing molten solder, a nozzle for dispensing molten solder on the substrate, a diaphragm pump with a pump cavity situated in fluid communication with the reservoir and with a flow intake portion of the nozzle, and an adjustable throttle for controlling the flow of molten solder from the reservoir to the diaphragm pump. The throttle defines an annular throttle gap between the reservoir and the pump cavity to vary the effective throttle area. A spring-loaded diaphragm for adjusting the throttle defines in part a pneumatic chamber. A solenoid valve is situated in a compressed gas feed passage extending to the pneumatic chamber.

Abstract: An apparatus for acoustically cooling automotive electronics in which an acoustic driver and acoustic reflector are disposed within a hollow member, such as a cross-car-beam of a vehicle. The frequency of the acoustic driver and the distance between the acoustic driver and the acoustic reflector are selected to generate a standing acoustic wave within the hollow member.

Abstract: There is disclosed herein an electronic circuit assembly, comprising: (1) a plastic molded substrate 10 having a first surface 12 with a mounting pad 14 disposed thereon; (2) a reinforcing member 20 having a first member portion 22 and a second member portion 24, wherein the first portion 22 is embedded within the substrate 10 beneath the first surface 12 thereof proximate the mounting pad 14 and wherein the second portion 24 is oriented generally parallel with and at a first predetermined distance h.sub.1 above the mounting pad 14; (3) an electronic surface mount component 18 having a termination 16 thereon, the component 18 being oriented such that the termination 16 is disposed at a second predetermined distance h.sub.2 above the second member portion 24; and (4) a solder joint 30 connecting the component termination 16 with the mounting pad 14 and the second member portion 24.

Abstract: An apparatus for dispensing solder includes a nozzle body having a plurality of flow channels formed therein. Each flow channel includes an inlet end and a dispenser end for dispensing solder. The nozzle body forms a nipple surrounding each dispenser end, and the nozzle body further forms a shielding chamber in communication with each dispenser end for protecting the respective nipple, and optionally providing flow of inerting gas and/or excluding ambient oxygen from the soldering area. The nozzle bodies comprise micro-machined silicon. Various flow channel configurations are provided for improved flow characteristics.

Abstract: There is disclosed herein a printed circuit board, one embodiment of which comprises: a dielectric substrate 10; a solid metallic heat sink 16 attached to or embedded within the substrate; a cavity 18 formed generally in the substrate, wherein at least one wall 20 of the cavity is defined by a surface 17 of the heat sink 16; a component mounting pad 14 disposed on the substrate proximate the cavity; a predetermined volume of electrically insulative liquid 22 contained within the cavity; and a thermally conductive member 24 embedded within the substrate, the member 24 being in direct thermal contact with each of the mounting pad 14 and the liquid 22.

Abstract: There is disclosed herein a surface mount printed circuit board having a substrate, at least one surface mount device, at least two mounting pads per device, solder joints connecting the terminations of the device to their respective mounting pads, at least one rectangular lifter pad on the substrate amid the mounting pads, and a solder mass on each lifter pad in contact with the bottom surface of the device. The inner and outer extensions of the mounting pads, the size, number, and shape of the lifter pads, and the amounts of solder deposited on the mounting and lifter pads are designed such that the solder joint has preferably convex outer fillets, the device is maintained at a predetermined height above the mounting pads, the inner fillet angle is maintained above a predetermined minimum angle to increase solder joint crack initiation time, and the overall solder joint crack propagation length is increased.

Abstract: A method for joining a component to a substrate applies a base solder portion to the substrate and provides a standoff solder portion in the base solder portion. The standoff solder portion has a higher melting temperature than the base solder portion and a height which substantially corresponds to a desired standoff height between the component and the substrate. The component is positioned on the standoff solder portion and the base solder portion is melted under reflow conditions to form a solder joint between the component and the substrate. This joint substantially encapsulates the standoff solder portion, wherein the reflow conditions create a dendritic structure between the base solder portion and the standoff solder portion.

Abstract: There is disclosed herein a self-shearing stencil for use in applying solder paste or other bonding material atop a printed circuit board (PCB) in a predefined pattern. The stencil 50 has a top surface 12, a bottom surface 14, a first surface cavity 16 in the top surface, and a second surface cavity 18 in the bottom surface proximate the first surface. The cavities 16/18 overlap in a predefined manner so as to be in open communication with each other. When the stencil is placed on the PCB, the cavities are filled with solder paste and the PCB is then lowered away from the stencil, whereupon a bottom ledge 26 (defined by the stencil material underneath the first cavity) shears off the solder paste in the first cavity from the paste in the second cavity.

Abstract: Method of surface mounting an electronic component to a bonding pad on one side of a supporting insulating board carrying a planar printed circuit thereon, the pad being connected to one or more conductors on the board by use of solder material subject to one or more gas trapping through-hole vias, comprising: (a) creating at least one vent channel below the top plane of the printed circuit and extending from a location at or closely adjacent to one of said vias to a location essentially near a periphery of solder material to be placed thereover; (b) planting a deposit of solder material between the component and pad; (c) bringing the component, solder material and pad together to form an assembly; and (d) heating the assembly to momentarily reflow the solder material in place without shifting, skewing, or tilting of the component, any trapped air in said one vias being allowed to expand and migrate away through the channel to at least the periphery of the pad.

Abstract: In order to dissipate heat from an electronic device, there is disclosed a method whereby with the use of metal planes embedded in an insulating substrate, heat generated by the electronic device can be transported and dissipated to a remote, more desirable location.

Abstract: An apparatus for dispensing solder includes a nozzle body having a plurality of flow channels formed therein. Each flow channel includes an inlet end and a dispenser end for dispensing solder. The nozzle body forms a nipple surrounding each dispenser end, and the nozzle body further forms a shielding chamber in communication with each dispenser end for protecting the respective nipple, and optionally providing flow of inerting gas and/or excluding ambient oxygen from the soldering area. The nozzle bodies comprise micro-machined silicon. Various flow channel configurations are provided for improved flow characteristics.

Abstract: An apparatus and method for soldering components to a circuit board. The apparatus includes a conveyor in a tunnel for transporting the board through a preheat zone, molten waves of solder including a turbulent wave and a laminar wave, and a cool down zone through which the board passes upon exit from the laminar flow wave of the solder wave. The improvement comprises at least one distributing manifold mounted in the tunnel having an inlet port for receiving a cold gas under pressure and at least one outlet nozzle for directing the cold gas to the circuit board, thereby rapidly cooling the circuit board and the components.