Self-Filleting Die Attach Paste

Abstract

A composition that will automatically flow (auto-flow) and form a fillet (self-fillet) will have a yield stress within the range of 1.8 Pa to 10 Pa (20 dynes/cm 2 to 100 dynes/cm 2 ). Such a composition can be designed by using an appropriate choice of filler, regardless of the resin system used in the composition.

1 . A composition comprising a resin and a filler, characterized in that the composition has a yield stress within the range of 1.8 Pa to 10 Pa, thereby automatically flowing and forming a fillet at 25° C. 
     
     
         2 . The composition according to  claim 1  in which the fillers are selected from the group consisting of silica, fumed silica, silicon carbide, boron nitride, diamond, alumina, aluminum hydroxide, vermiculite, mica, wollastonite, calcium carbonate, titania, sand, glass, barium sulfate, zirconium, carbon black, organic fillers, tetrafluoroethylene, trifluoroethylene, vinylidene fluoride, vinyl fluoride, vinylidene chloride, vinyl chloride, and combinations of these. 
     
     
         3 . The composition according to  claim 2  in which the fillers are selected from the group consisting of silica and fumed silica. 
     
     
         4 . The composition according to  claim 1  in which the fillers are selected from the group consisting of carbon black, graphite; gold, silver, copper, platinum, palladium, nickel, aluminum, metal alloys, metal coated glass, metal coated organic polymer, metal coated silica, and combinations of these. 
     
     
         5 . The composition according to  claim 1  in which the resins are selected from the group consisting of epoxy, maleimide, bismaleimide, acrylates, methacrylates, cyanate esters, vinyl ethers, thiol-enes, resins that contain carbon to carbon double bonds attached to an aromatic ring and conjugated with the unsaturation in the aromatic ring (such as compounds derived from cinnamyl and styrenic starting compounds), fumarates maleates, polyamides, phenoxy compounds, benzoxazines, polybenzoxazines, polyether sulfones, polyimides, siliconized olefins, polyolefins, polyesters, polystyrenes, polycarbonates, polypropylenes, poly(vinyl chloride)s, polyisobutylenes, polyacrylonitriles, poly(vinyl acetate)s, poly(2-vinylpyridine)s, cis-1,4-polyisoprenes, 3,4-polychloroprenes, vinyl copolymers, poly(ethylene oxide)s, poly(ethylene glycol)s, polyformaldehydes, polyacetaldehydes, poly(b-propiolacetone)s, poly(10-decanoate)s, poly(ethylene terephthalate)s, polycaprolactams, poly(11-undecanoamide)s, poly(m-phenylene-terephthalamide)s, poly(tetramethlyene-m-benzenesulfonamide)s, polyester polyarylates, poly(phenylene oxide)s, poly(phenylene sulfide)s, poly(sulfone)s, polyetherketones, polyetherimides, fluorinated polyimides, polyimide siloxanes, poly-isoindolo-quinazolinediones, polythioetherimide poly-phenyl-quinoxalines, polyquinixalones, imide-aryl ether phenylquinoxaline copolymers, polyquinoxalines, polybenzimidazoles, polybenzoxazoles, polynorbornenes, poly(arylene ethers), polysilanes, parylenes, benzocyclobutenes, hydroxyl-(benzoxazole) copolymers, poly(silarylene siloxanes), and combinations of these. 
     
     
         6 . The composition according to  claim 5  in which the resins are selected from the group consisting of epoxy, maleimide, bismaleimide, acrylates, methacrylates, cyanate esters, vinyl ethers, thiol-enes, resins that contain carbon to carbon double bonds attached to an aromatic ring and conjugated with the unsaturation in the aromatic ring (such as compounds derived from cinnamyl and styrenic starting compounds), fumarates maleates, and combinations of these. 
     
     
         7 . The composition according to  claim 6  in which the resins are selected from the group consisting of epoxy, maleimide, bismaleimide, acrylates, methacrylates, and combinations of these.