Abstract:
The adhesive layer of the novel transfer tape contains electrically and thermally conductive particles such as silver which are preferably spherical and are larger than the thickness of the adhesive between particles. When used to bond two rigid substrates together, pressure is applied to the substrates to flatten the particles to the thickness of the adhesive between particles, thus making good electrical and thermal connection between the substrates through each particle.
Abstract:
An adhesive interconnecting means is comprised of one or more conductors on an insulating substrate, a first adhesive layer, said first layer being anisotropically conductive and disposed over said conductors and substrate and a second adhesive layer said second layer being a flowable adhesive that extends over the first substrate and anisotropically conductive layer. The anisotropically conductive adhesive is comprised of a nonhomogenous mixture of conductive particles in a nonconductive adhesive binder; the conductive particles, of random size and shape, are dispersed randomly throughout the mixture in noncontiguous conductive units, each unit being comprised of one or more individual particles, the units being sufficiently spaced apart to preclude electrical conductivity between adjacent conductive areas on the same substrate. The flowable adhesive extends over the surface of the first substrate and conductive units to provide insulation whereby upon positioning the first substrate conductors in an overlapping conducting relationship to the second substrate conductors and applying pressure to the positioned areas, the adhesive flows from the positioned areas and exposes the conductive units thus bringing the exposed units into contact and electrical interconnection with the second substrate conductors accompanied by the adhesion of the remaining first substrate surface to the surface of the second substrate.
Abstract:
Sheet material useful for making bonded electrical connections, especially to sets of small side-by-side terminal pads. In one typical form, the sheet material is an elongated tape comprising an elongated flexible insulating backing; a plurality of narrow spaced parallel elongated electrically conductive stripes on the backing; and electrically conductive adhesive disposed over the stripes comprising a layer of adhesive material in which are dispersed a monolayer of electrically conductive elements which have an average thickness greater than the average thickness of the adhesive layer, and the top edges of which are higher than at least part of the exterior surface of the adhesive layer surrounding the element.
Abstract:
An example stretchable device is described that includes electrical contacts and an interconnect coupling the electrical contacts. The interconnect has a meander-shaped configuration that includes at least one nested serpentine-shaped feature. The interconnect can be conductive or non-conductive. The meander-shaped configuration can be a serpentine structure, providing a serpentine-in-serpentine configuration.
Abstract:
A boat (10) onto which solder balls (16) or columns are loaded for an attach process can be used in a universal attach line has a number of attach stations (32-44) to accommodate different types of attach processes. Depending on the process and the desired configuration and form factor of the array of solder balls (16) or columns, a template (14a, 14b) is selected that covers some of the holes (12) in the universal boat (10), and exposes other holes (12). The holes (12) are configured and sized to hold solder balls (16) in the holes (12) such that the solder balls (16) protrude above the top surface of the boat (10) by a predetermined height. This prevents damage to the solder balls (16) while ensuring that the solder balls (16) protrude enough to accommodate imperfectly flat packages that are placed on the array of solder balls (16) held in the boat (10). Vacuum applied through the holes (12) help to securely hold the balls (16) in place, and a substrate (18) is placed onto the solder balls (16). Once loaded with balls (16) or columns, the boat (10) is transported to only the appropriate attach stations in the universal attach line, where the different attach operations for a given attach process, such as high temperature ball attach, eutectic ball attach, or column attach, are performed. Also provided is a method of fabricating laminate assemblies that determines the ideal weight (W) of underfill to be dispensed, based on the size of the semiconductor die (144) and the gap (142) between the die (144) and the laminate substrate. Underfill (150) is dispensed in a single step in an amount between 1.1W and 1.3W to form fillets (52, 54) that cover at least 15% of the height of the semiconductor die (144) on all four sides of the die. The amount of underfill (150) ensures that the fillet coverage imbalance is 30% or less for each of the pairs of opposing sides of the die (144), thereby improving solder joint reliability.
Abstract:
A process for the preparation of an anisotropic conducting material, which process comprises the steps of: (i) providing a strip or sheet (10) of a non-conducting matrix and laminating to each side thereof at least one layer of a release material (11, 12) in order to form a composite matrix (13); (ii) forming an array of holes (14) in a predetermined pattern in the composite matrix (13) from step (i); (iii) passing the matrix (13) from step (ii) through a coating head (1) which simultaneously fills the holes (14) of the array in the composite matrix (13) from both sides of the said matrix (13) with a conducting material (15); (iv) curing or drying the composite filled matrix from step (iii); and (v) removing at least one layer of release material (11, 12) from each side of the matrix.
Abstract:
The present invention provides a number of interrelated methods for the production of random and ordered arrays of particles and recesses, as well as films containing such arrays and recesses. The present invention also relates to the random and ordered arrays of particles and films prepared therefrom. The ordered arrays are obtained by the use of ferrofluid compositions which may be curable, solidifiable or non-curing/non-solidifiable. The arrays and films may contain electrically-conductive particles useful in electronic applications for effecting contact between leads or pads.
Abstract:
The anisotropic conductive film (ACF) (1) comprises a sheet-like insulating adhesive film (2) and plural rows of electrically conductive particles (3). Any one electrically conductive particle (3a) is disposed equidistant from 6 surrounding adjacent electrically conductive particles (3b-3g). This particular configuration provides high density of electrically conductive particles (3) and a large current carrying capacity. The direction of each row of the electrically conductive particles (3) is slanted at a predetermined angle with respect to the normal to one side of the ACF (1) or the sides of the electrodes to be interconnected. This minimizes the number of the electrically conductive particles (3) on the sides of the electrodes and thus maintains large current carrying capacity.