Silverbrook Research Pty Ltd

Zamtec Limited

Kiangkai Tankongchumruskul

Laval Chung-Long-Shan

Kia Silverbrook

Elmer Dimaculangan Perez

Nadine Lee-Yen Chew

Susan Williams

A method of depositing encapsulant on a line of wire bonds to a die is described, the die having a back surface in contact with the support structure and an active surface opposing the back surface, the active surface having electrical contact pads and functional elements spaced from the contact pads. The method involves the steps of providing a die mounted to the support structure, positioning a barrier between the contact pads and the functional elements, the barrier being proximate to, but spaced from the active surface, depositing a bead of encapsulant onto the electrical contact pads while the barrier remains stationary such that the barrier prevents the encapsulant from contacting the functional elements, removing the barrier when the bead of encapsulant has been deposited. The fluidic resistance generated by the gap between the barrier and the active surface means that the amount of encapsulant that flows into the gap and onto the active surface is almost constant. The reduced flow variations make the encapsulant front closely correspond to the shape of the barrier. Greater control of the encapsulant front allows the functional elements of the active surface of the die to be closer to the contact pads.

Wire bond encapsulant control method

An electronic component that has a support structure with a plurality of electrical conductors, a series of wire bonds, each of the wire bonds extending from one of the electrical conductors respectively, each of the wire bonds having an end section contacting the electrical conductor and an intermediate section contiguous with the end section, a bead of dam encapsulant encapsulating the electrical conductors and the end section of each of the wire bonds, and a bead of fill encapsulant contacting the bead of dam encapsulant and encapsulating the intermediate portion of each of the wire bonds. The dam encapsulant has a higher modulus of elasticity than the fill encapsulant.

Electronic component with wire bonds in low modulus fill encapsulant

An electronic component assembly that has a supporting structure, an integrated circuit die with a plurality of contacts pads, a printed circuit board with a plurality of conductors, the integrated circuit die and the PCB being mounted to the supporting structure by a die attach film such that they are adjacent and spaced from each other and, wire bonds electrically connecting the contact pads to the conductors. An intermediate portion of each of the wire bonds is adhered to the die attach film to lower the profile of the wire bond arcs.

Assembly of electronic components

A method for profiling a bead of encapsulant extending along an edge of a die mounted to a supporting structure, by depositing a bead of encapsulant onto wire bonds along the edge of the die, positioning a profiling surface over the die at a predetermined spacing from the die, moving the profiling surface across the bead before the bead of encapsulant has cured to reshape the bead profile and, curing the bead of encapsulant. The invention has found that the encapsulant can be effectively shaped by a profiling surface without stripping the encapsulant from the wire bonds. The normally convex-shaped upper surface of the encapsulant bead can be pushed to one side of the bead with the profiling surface. With a lower encapsulant bead, the active surface can be brought into closer proximity with another surface without making contact. For example, the nozzle array on a printhead IC can be 300 microns to 400 microns from the paper path. By collapsing or flattening the wire bond arcs before applying and profiling a bead of encapsulant, the nozzle array on the printhead IC can be less than 100 microns from the paper path.

Method of wire bond encapsulation profiling

A method of forming an asymmetrical encapsulant bead on a series of wire bonds electrically connecting a micro-electronic device to a series of conductors, the micro-electronic device having a planar active surface. The method has the steps of positioning the die and the wire bonds beneath an encapsulant jetter that jets drops of encapsulant on to the wire bonds, the drops of encapsulant following a vertical trajectory, tilting the die such that the active surface is inclined to the horizontal and, jetting the drops of encapsulant to form a bead of encapsulant material covering the series of wire bonds, the bead having a cross sectional profile that is asymmetrical about an axis parallel to a normal to the active surface.

Method of forming assymetrical encapsulant bead

A method of profiling a wire bond between a contact pad on a die, and a conductor on a supporting structure, by electrically connecting the contact pad on the die to the conductor on the supporting structure with a wire bond, the wire bond extending in an arc from the contact pad to the conductor, pushing on the wire bond to collapse the arc and plastically deform the wire bond, and then releasing the wire bonds such that the plastic deformation maintains the wire bond in a flatter profile shape. The strength of the wire bond is known to be relatively small; of the order of 3 to 5 grams force. However, the Applicant's work has found that the wire bond structure is robust enough to withstand a certain degree of work hardening from plastic deformation. The arc of the wire bond can be deformed into a flatter profile without compromising the electrical connection with the PCB.

Method of reducing wire bond profile height in integrated circuits mounted to circuit boards

A wirebonder for electrically connecting an integrated circuit die with conductors on a printed circuit board. The wirebonder has a bonding tool for attaching wire bonds from the integrated circuit die to the conductors of the printed circuit board and a wire engaging structure for deforming the wire bonds such that they have a flatter profile shape.

Wirebonder forming low profile wire bonds between integrated circuits dies and printed circuit boards

A method of jetting drops of encapsulant from an encapsulant jetter, the drops including primary drops and satellite drops that are much smaller than the primary drops. The method has the steps of providing a series of wire bonds electrically connecting a micro-electronic device to a series of conductors, jetting the drops of encapsulant from the jetter and, inducing a gas flow with a velocity sufficient to draw the satellite drops in a predetermined direction away from the series of wire bonds while having negligible effect on the primary drops.

Method of controlling satellite drops from an encapsulant jetter

A method of reducing wire bond loop heights in wire bonds electrically connecting an integrated circuit die with a contact pad to a printed circuit board with a conductor, by mounting the integrated circuit die such that the contact pad is spaced from the conductor, positioning an adhesive surface between the contact pad and the conductor on the printed circuit board, attaching wire to one of the contact pad or the conductor, drawing the wire towards the other of the contact pad or the conductor, allowing the wire to contact the adhesive surface, and, attaching the wire to the other of the contact pad of the conductor to form a wire bond adhered to the adhesive surface and a point intermediate its ends.

Method of adhering wire bond loops to reduce loop height

A microprocessor device that has a support structure with a chip mounting area and a conductor mounting area. An inkjet printhead IC is supported on the chip mounting area. The inkjet printhead IC has a back surface in contact with the chip mounting area and an active surface opposing the back surface. The active surface has electrical contact pads and an array of ink ejection nozzles. The active surface has electrical contact pads for its circuitry and functional elements. A plurality of electrical conductors are, at least partially, supported on the conductor mounting area and a series of wire bonds extending from the electrical contact pads to the plurality of electrical conductors supported on the conductor mounting area wherein, the chip mounting area is raised relative to the conductor mounting area. By raising the chip mounting area relative to the rest of the PCB, or at least the conductors connected to the PCB end of the wire bonds, the top of the arc formed by the layer is much closer to the active surface of the die. This, in turn, allows the bead of encapsulant to have a lower profile relative to the active surface. With a lower encapsulant bead, the active surface can be brought into closer proximity with another surface without making contact. For example, the nozzle array on a printhead IC can be 300 microns to 400 microns from the paper path.

Integrated circuit support for low profile wire bond

A method encapsulating wire bonds that extend between a die and conductors on a supporting substrate, by contacting an edge of a profiling blade with the encapsulant material to form a bead of the encapsulant on the edge, positioning the edge such that the bead contacts the die and, moving the profiling blade relative to the die to cover the wire bonds with the encapsulant. Wiping the encapsulant over the wire bonds with a profiling blade provides control of the encapsulant front as well as the height of the encapsulant relative to the die. The movement of the profiling surface relative to the die can closely controlled to shape the encapsulant to a desired form. Using the example of a printhead die, the encapsulant can be shaped to present an inclined face rising from the nozzle surface to a high point over the wire bonds. This can be used by the printhead maintenance facilities to maintain contact pressure on the wiping mechanism. However, it will be appreciated that the encapsulant can be shaped to have ridges, gutters, grooves and so on by using a particular shape of profiling blade edge and relative movement with the die.

Method of encapsulating wire bonds

A method of profiling a series of wire bonds between a line of contact pads on a die, and a corresponding set of conductors on a supporting structure. The method involves electrically connecting each of the contact pads on the die to a corresponding conductor on the supporting structure with a respective wire bond, each of the wire bonds extending in an arc from the contact pad to the conductor and, pushing on each of the wire bonds individually to collapse the arc and plastically deform the wire bond such that the plastic deformation maintains the wire bond in a flatter profile shape. The support structure has a chip mounting area for supporting the die. The die has a back surface in contact with the chip mounting area and an active surface opposing the back surface, the active surface having the contact pads, and the chip mounting area being raised relative to the remainder of the support structure such that the contact pads are raised relative to the conductors.

Method of wire bonding an integrated circuit die and a printed circuit board

An electronic device that has an integrated circuit die with a plurality of contacts pads, a printed circuit board with a plurality of conductors corresponding to each of the contact pads respectively, wire bonds electrically connecting each of the contact pads to the corresponding conductors and, an adhesive surface positioned between the contacts pads and the corresponding conductors. The wire bonds are secured to the adhesive surface to hold them in a low profile configuration.

Electronic device with wire bonds adhered between integrated circuits dies and printed circuit boards

A method of profiling a series of wire bonds between a line of contact pads on a die, and a corresponding set of conductors on a supporting structure, by electrically connecting each of the contact pads on the die to a corresponding conductor on the supporting structure with a respective wire bond, each of the wire bonds extending in an arc from the contact pad to the conductor, and, pushing on each of the wire bonds individually to collapse the arc and plastically deform the wire bond such that the plastic deformation maintains the wire bond in a flatter profile shape.

Method of forming low profile wire bonds between integrated circuits dies and printed circuit boards

A method of applying encapsulant to a die mounted to a support structure by providing a die mounted to the support structure, the die having a back surface in contact with the support structure and an active surface opposing the back surface, the active surface having electrical contact pads, positioning a barrier proximate the electrical contact pads and spaced from the active surface to define a gap and, depositing a bead of encapsulant onto the electrical contact pads such that one side of the bead contacts the barrier and a portion of the bead extends into the gap and onto the active surface. Placing a barrier over the active surface so that it defines a narrow gap allows the geometry of the encapsulant front (the line of contact between the encapsulant and the active surface) can be more closely controlled. Any variation in the flowrate of encapsulant from the needle tends to cause bulges or valleys in the height of the bead and or the PCB side of the bead. The fluidic resistance generated by the gap between the barrier and the active surface means that the amount of encapsulant that flows into the gap and onto the active surface is almost constant. The reduced flow variations make the encapsulant front closely correspond to the shape of the barrier. Greater control of the encapsulant front allows the functional elements of the active surface of the die to be closer to the contact pads.

Growing community of inventors

Balmain, Australia

Kiangkai Tankongchumruskul