Method of reconstituted substrate formation for advanced packaging applications

Abstract

Embodiments of the present disclosure generally describe methods for minimizing the occurrence and the extent of die shift during the formation of a reconstituted substrate in fan-out wafer level packaging processes and reconstituted substrates formed therefrom. Die shift is a process defect that occurs when a die (device) moves from its intended position within a reconstituted substrate during the formation thereof. Generally, the reconstituted substrates disclosed herein include a device immobilization layer and/or a plurality of device immobilization beads over and/or adjacent to a plurality of singular devices (individual dies), and a cured epoxy molding compound formed there over. The device immobilization layer and/or the plurality of device immobilization beads immobilize the plurality of singular devices and prevents them from shifting on the carrier substrate during the molding process.

1 . A substrate, comprising:
 a reconstituted substrate, comprising:
 a plurality of devices disposed in a cured molding compound; and 
 a device immobilization layer interposed between the plurality of devices and the molding compound, wherein the device immobilization layer comprises a polymerized reaction product of one or more monomers and one or more catalytically dissociated initiator precursors. 
   
     
     
         2 . The substrate of  claim 1 , further comprising an electrostatic discharge layer disposed between the cured molding compound and individual ones of the plurality of devices. 
     
     
         3 . The substrate of  claim 1 , further comprising one or more redistribution layers disposed on the reconstituted substrate, wherein each of the one or more redistribution layers comprises a dielectric material layer having a plurality of interconnect structures disposed therethrough. 
     
     
         4 . The substrate of  claim 1 , wherein the one or more monomers are selected from the group consisting of ethyleneglycol diacrylate, t-butylacrylate, N,N-dimethylacrylamide, vinylimidazole, 1-3-diethynylbenzene, 4-vinyl pyridine, poly vinyl pyridine, poly 4-vinyl pyridine, polyphenylacetylene, N,N-dimethylaminoethylmethacrylate, divinylbenzene, poly divinylbenzene, glycidyl methacrylate, poly thiophene, ethyleneglycol dimethacrylate, tetrafluoroethylene, dimethylaminomethylstyrene, perfluoroalkyl ethylmethacrylate, trivinyltrimethoxy-cyclotrisiloxane, furfuryl methacrylate, cyclohexyl methacrylate-co-ethylene glycol dimethacrylate, pentafluorophenyl methacrylate-co-ethylene glycol diacrylate, 2-hydroxyethyl methacrylate, methacrylic acid, 3,4-ethylenedioxythiophene, and combinations thereof. 
     
     
         5 . The substrate of  claim 1 , wherein the one or more initiator precursors are selected from the group consisting of hydrogen peroxide, alkyl peroxides, aryl peroxides, hydroperoxides, halogens, azo compounds, and combinations thereof. 
     
     
         6 . The substrate of  claim 1 , wherein the device immobilization layer comprises a continuous layer interposed between the cured molding compound and the plurality of devices disposed therein. 
     
     
         7 . The substrate of  claim 1 , wherein the device immobilization layer comprises a discontinuous layer comprising a plurality of immobilization patches interposed between the cured molding compound and individual ones of the plurality of devices. 
     
     
         8 . The substrate of  claim 1 , wherein the polymerized reaction product comprises poly(glycidyl methacrylate-co-divinylbenzene), poly(glycidyl methacrylate-co-methacrylamide), poly(ethyleneglycol diacrylate), poly(t-butylacrylate), poly N,N-dimethylacrylamide, poly(vinylimidazole), poly(1-3-diethynylbenzene), poly(phenylacetylene), poly(N,N-dimethylaminoethylmethacrylate) (p(DMAM), poly (divinylbenzene), poly(glycidyl methacrylate) (p(GMA)), poly (ethyleneglycol dimethacrylate), poly (tetrafluoroethylene), poly(tetrafluoroethylene) (PTFE), poly(dimethylaminomethylstyrene) (p(DMAMS), poly(thiophene), poly(vinylpyridine), poly(perfluoroalkyl ethylmethacrylate), poly(trivinyltrimethoxy-cyclotrisiloxane), poly(furfuryl methacrylate), poly(cyclohexyl methacrylate-co-ethylene glycol dimethacrylate), poly(pentafluorophenyl methacrylate-co-ethylene glycol diacrylate), poly(2-hydroxyethyl methacrylate-co-ethylene glycol diacrylate), poly(methacrylic acid-co-ethylene glycol dimethacrylate), poly(3,4-ethylenedioxythiophene), or combinations thereof. 
     
     
         9 . The substrate of  claim 8 , wherein the polymerized reaction product comprises poly(glycidyl methacrylate) (p(GMA)). 
     
     
         10 . The substrate of  claim 1 , wherein the device immobilization layer has a thickness between about 0.5 μm and about 100 μm. 
     
     
         11 . A substrate, comprising:
 a reconstituted substrate, comprising:
 a plurality of devices disposed in a cured molding compound, each of the plurality of devices comprising a first surface having one or more bond pads disposed therein and one or more second surfaces which are substantially normal to the first surface; and 
 a plurality of device immobilization beads interposed between individual ones of the plurality of devices and the cured molding compound, wherein each of the device immobilization beads cover at least portions of the one or more second surfaces, and wherein portions of each of the respective device immobilization beads extend laterally outward from the first surfaces of the devices disposed adjacent thereto. 
   
     
     
         12 . The substrate of  claim 11 , further comprising an electrostatic discharge layer interposed between the cured molding compound and the plurality of devices. 
     
     
         13 . The substrate of  claim 11 , further comprising one or more redistribution layers disposed on the reconstituted substrate, wherein each of the one or more redistribution layers comprises a dielectric material layer having a plurality of interconnect structures disposed therethrough. 
     
     
         14 . The substrate of  claim 11 , wherein the plurality of device immobilization beads comprise a UV cured reaction product of a mixture of one or more functional polymers, functional oligomers, functional monomers, or reactive diluents. 
     
     
         15 . The substrate of  claim 14 , wherein the plurality of device immobilization beads comprise a UV cured reaction product of a mixture comprising one or a combination of multifunctional acrylates, monofunctional acrylate oligomers, multifunctional acrylate oligomers, monofunctional acrylate monomers, and multifunctional acrylate monomers. 
     
     
         16 . The reconstituted substrate of  claim 11 , wherein the device immobilization beads are located at one or more corners of each respective device, are located between corners of each respective device, a combination thereof, or form a continuous surface about a perimeter of each respective device. 
     
     
         17 . The substrate of  claim 16 , wherein the plurality of device immobilization beads form a continuous surface about the perimeter of the device. 
     
     
         18 . A packaged device, comprising:
 a device disposed in a cured molding compound, the device comprising a first surface having one or more bond pads disposed therein and one or more second surfaces which are substantially normal to the first surface;   a plurality of device immobilization beads interposed between the device and the cured molding compound, wherein each of the device immobilization beads cover at least a portion of the one or more second surfaces of the device, and wherein portions of each of the device immobilization beads extend laterally outward from the first surfaces of the devices disposed adjacent thereto; and   one or more redistribution layers disposed on the first surface of the device, wherein each of the one or more redistribution layers comprises a dielectric material layer having a plurality of interconnect structures disposed therethrough.   
     
     
         19 . The packaged device of  claim 18 , wherein the device immobilization beads are located at one or more corners of the device, are located between the corners of the device, a combination thereof, or form a continuous surface about a perimeter of the device. 
     
     
         20 . The packaged device of  claim 19 , further comprising an electrostatic discharge layer interposed between the cured molding compound and the device.