Abstract: A method of noncontact dispensing is provided for conformal coating applications by jetting a viscous material onto a substrate. Dispensing by a jetting process results in small wetted areas thus providing highly discrete and selective conformal coating capabilities. Enhanced selectivity permits the coating of small areas and geometries and provides excellent edge definition between coated and uncoated areas.

Abstract: Apparatus and methods for preapplying discrete amounts of underfill material of a component on a component substrate before the solder bumps of the component are joined by reflow with a packaging substrate to create a microelectronics package. The underfill material is preferably applied by a noncontact dispensing technique as discrete amounts at interstitial areas on an active surface of the component substrate defined between nearest-neighbor solder bumps. The underfill material forms a continuous meniscus of underfill material across the interstitial areas not occupied by the solder bumps and forms a collar encircling each of the solder bumps. The cured underfill material strengthens and improves the reliability of the solder joints formed by the bump reflow.

Abstract: A method and apparatus for underfilling a gap between a multi-sided die and a substrate with an encapsulant material. The die and/or the substrate is heated non-uniformly by a heat source to generate a temperature gradient therein. The heated one of the die and the substrate transfers heat energy in proportion to the temperature gradient to the encapsulant material moving in the gap. The differential heat transfer steers, guides or otherwise directs the movement of the encapsulant material in the gap. The temperature gradient may be established with heat transferred from the heat source to the die and/or the substrate by conduction, convection, or radiation. The temperature gradient may be dynamically varied as the encapsulant material moves into the gap.

Abstract: A viscous material noncontact jetting system has a jetting dispenser mounted for relative motion with respect to a surface. A control is operable to cause the jetting dispenser to jet a viscous material droplet that is applied to the surface as a viscous material dot. A device, such as a camera or weigh scale, is connected to the control and provides a feedback signal representing a size-related physical characteristic of the dot applied to the surface. The size-related physical characteristics of subsequently applied dots is controlled by heating and cooling, or adjusting a piston stroke in the jetting dispenser, in response to the size-related physical characteristic feedback. Dispensed material volume control and velocity offset compensation are also provided.

Abstract: A bead of liquid encapsulant or underfilled material (16) is dispensed along one or more edges of the flip chip (12). A plenum is located along the sides of the chip (12) in which encapsulant or underfilled material has not been deposited, such as opposite the dispensed material. Thereafter, the plenum is subject to a negative pressure source for drawing a vacuum to the area beneath the chip (12) and the substrate (10). The negative pressure aids in the natural capillary underfilling action and for quicker and more effective underfilling of the chip. Simultaneous underfilling of a plurality of chips (12) can be achieved by mounting a like plurality of vacuum tools to a plate which is moved into registration with a like plurality of chip/substrate workstations. By operatively connecting the vacuum tools to a controller, and to appropriate valves which can be set to adjust the vacuum level.

Abstract: Methods for underfilling a gap between a component and a component carrier, such as a die joined to a substrate by solder electrical interconnections, with an underfill material. One or more chambers or passageways are provided in either the component carrier at a location beneath the intended position of the component or in the component itself. The component and component carrier are heated and a volume of underfill material is introduced into each passageway. After introduction, the underfill material flows or moves to fill the gap between the component and the component carrier. A fillet may be optionally formed by adjusting the temperature during the underfilling operation.

Abstract: Solder compositions are introduced to interface between an IC chip and its associated heat exchanger cover. The solder compositions have a solidus-liquidus temperature range that encompasses the IC chip operational temperature range. The solder composition has the desired property of absorbing and rejecting heat energy by changing state or phase with each temperature rise and decline that result from temperature fluctuations associated with the thermal cycles of the integrated circuit chips. The electronic module cover is a cap with a heat exchanger formed or attached as a single construction, and made of the same material as the substrate, or made with materials of compatible thermal coefficients of expansion to mitigate the effects of vertical displacement during thermal cycling.

Abstract: A method and apparatus for underfilling a gap between a multi-sided die and a substrate with an encapsulant material. The die and/or the substrate is heated non-uniformly by a heat source to generate a temperature gradient therein. The heated one of the die and the substrate transfers heat energy in proportion to the temperature gradient to the encapsulant material moving in the gap. The differential heat transfer steers, guides or otherwise directs the movement of the encapsulant material in the gap. The temperature gradient may be established with heat transferred from the heat source to the die and/or the substrate by conduction, convection, or radiation. The temperature gradient may be dynamically varied as the encapsulant material moves into the gap.

Abstract: Solder compositions are introduced to interface between an IC chip and its associated heat exchanger cover. The solder compositions have a solidus-liquidus temperature range that encompasses the IC chip operational temperature range. The solder composition has the desired property of absorbing and rejecting heat energy by changing state or phase with each temperature rise and decline that result from temperature fluctuations associated with the thermal cycles of the integrated circuit chips.

Abstract: Solder compositions are introduced to interface between an IC chip and its associated heat exchanger cover. The solder compositions have a solidus-liquidus temperature range that encompasses the IC chip operational temperature range. The solder composition has the desired property of absorbing and rejecting heat energy by changing state or phase with each temperature rise and decline that result from temperature fluctuations associated with the thermal cycles of the integrated circuit chips. A path for high thermal conduction (low thermal resistance) from the IC chip to the heat exchanger to the ambient air is provided by an electronic module cover, configured as a cap with a heat exchanger formed or attached as a single construction, and made of the same material as the substrate, or made with materials of compatible thermal coefficients of expansion to mitigate the effects of vertical displacement during thermal cycling.

Abstract: A heat sink in a heat transfer relationship with a substrate such as an integrated chip, chip carrier, or other electronic package. The heat sink is connected to a frame which is connected to a printed circuit board or other suitable support on which the substrate is positioned. The heat sink, which extends through an aperture in the frame is coupled to a surface of the substrate. The heat sink is mechanically decoupled from the substrate. Large heat sinks may be thermally connected to surface mount substrates mounted using technologies such as ceramic ball or column grid arrays, plastic ball or column grid arrays, or solder balls or columns. The heat sink is attached coaxially through the aperture to the substrate. After assembly and lead/tin or other metallic surface mount interconnects are relaxed such that the substrate and is completely supported by the frame and the heat sink imparts zero or nearly zero downward force.

Abstract: A non-destructive method for identifying off-composition solder columns of for example, a ceramic column grid array. The method is performed at the ceramic module level prior to card assembly to avoid costly loss or rework post card assembly. The assembly of solder columns on a substrate is heated to a temperature below the melting temperature of pure-composition solder and above the temperature of attachment of a solder column to an organic board. Heating the assembly produces visually detectable changes characteristic of off-composition solder which are used for identifying which solder columns are composed of off-composition solder.

Abstract: A heat sink is placed in a heat transfer relationship with a substrate such as an integrated chip, chip carrier, or other electronic package, without imparting stressful forces to the substrate by connecting the heat sink to a frame which is connected to a support such as a printed circuit board or other suitable carrier on which the substrate is positioned. The heat sink extends through an aperture in the frame and is in heat transfer relationship with a surface of the substrate; however, it is mechanically decoupled from the substrate. The invention has particular application in thermally connecting large heat sinks to substrates that are surface mounted on the support using technologies such as ceramic ball or column grid arrays, plastic ball or column grid arrays, or solder balls or columns.

Abstract: A method for causing an open circuit in an electrical conductor is provided, including the steps of: conducting a direct current through the conductor; and applying heat at a selected location on the conductor whereat it is desired to cause the open circuit of the conductor.

Abstract: In accordance with the present invention, we provide a new method for relieving stresses in the device-substrate interconnection structure which greatly enhances the resistance of the interconnection solder bonds to fatigue failure. In accordance with the aforementioned object of the process of our invention for forming improved solder interconnections between integrated circuit semiconductor devices and the supporting substrate, the process includes the step of joining the device I/O pads to the corresponding I/O pads of the substrate by positioning the device over the substrate with solder material selectively positioned between the respective I/O pads, heating the assembly to at least the melting point of the solder material, and cooling to solidify the solder. Subsequently, the resultant device-substrate is annealed by heating to an annealing temperature in the range of 115.degree. to 135.degree. C. and maintaining this temperature for a time in excess of 2 days.

Abstract: An improved solder interconnection for forming I/O connections between an integrated semiconductor device and a support substrate having a plurality of solder connections arranged in an area array joining a set of I/O's on a flat surface of the semiconductor device to a corresponding set of solder wettable pads on a substrate, the improvement being a band of dielectric organic material disposed between and bonded to the device and substrate embedding at least an outer row of solder connections leaving the center inner solder connections and the adjacent top and bottom surfaces free of dielectric material.