Method of producing a laminated structure

Abstract

A method of laminating a structure comprises at least two layers and a photopolymerizable adhesive composition between the layers, at least one of the layers being opaque, colored, or reflective. One or both of the layers is transmissive to actinic radiation in wavelengths in the range of greater than 400 nm and up to 1200 nm. The photopolymerizable adhesive composition absorbs radiation in the identified spectral region of the radiation transmissive layer. Curing is effected by directing radiation in the identified spectral region through the radiation transmissive layer and produces a laminated structure. An underfilled flip chip assembly on an integrated circuit board substrate can be prepared by the method described above. The photopolymerizable adhesive composition can be applied directly to one or both surfaces of an aligned integrated chip and circuit board substrate or the chip aligned on an integrated circuit board substrate can be capillary underfilled with the photopolymerizable adhesive composition, which is subsequently cured. Data storage disks can also be prepared by the method of the invention.

1 . A method of laminating a structure comprising the steps of: 
 a) providing a structure comprising at least two layers and a photopolymerizable adhesive composition between said layers, 
 1) at least one of said layers being opaque or colored and transmissive to actinic radiation in an identified spectral region having one or more wavelengths greater than 400 nm and up to 1200 nm, said layer being essentially free of cellulosic and olefinic functionality,  
 2) said photopolymerizable composition comprising a photopolymerizable moiety and a photoinitiator therefor that absorbs actinic radiation in said identified spectral region of said radiation transmissive layer, said photopolymerizable moiety being polymerizable in a hydrosilation, cationic, or free radical polymerization process, with the proviso that said free radical polymerization process is free of dialkylaminobenzophenone sensitizer,  
   b) directing actinic radiation within said identified spectral region through said radiation transmissive layer and into said photopolymerizable composition for less than two minutes to cure said photopolymerizable composition,    whereby said resulting polymerized composition adheres to said layers and provides a laminated structure.    
     
     
         2 . The method according to  claim 1  wherein said radiation transmissive layer is selected from the group consisting of plastics, ceramics, glasses, and papers.  
     
     
         3 . The method according to  claim 2  wherein said radiation transmissive layer bears a metallized surface.  
     
     
         4 . The method according to  claim 2  wherein said radiation transmissive layer is selected from the group consisting of opaque materials.  
     
     
         5 . The method according to  claim 2  wherein said radiation transmissive layer is selected from the group consisting of colored materials.  
     
     
         6 . The method according to  claim 1  wherein said radiation transmissive layer absorbs one or both of UV and visible radiation.  
     
     
         7 . The method according to  claim 1  wherein said photopolymerizable moiety of said photopolymerizable composition comprises one or both of free-radically and cationically polymerizable materials.  
     
     
         8 . The method according to  claim 7  wherein said photopolymerizable moiety of said photopolymerizable composition comprises one or more of 1,2-, 1,3-, and 1,4-cyclic ethers and vinyl ethers.  
     
     
         9 . The method according to  claim 7  wherein said photopolymerizable moiety of said photopolymerizable composition comprises one or more ethylenically-unsaturated bonds.  
     
     
         10 . The method according to  claim 7  wherein said photopolymerizable moiety of said photopolymerizable composition comprises one or more of mono-, di-, and poly-acrylates and -methacrylates, unsaturated amides, and vinyl compounds.  
     
     
         11 . The method according to  claim 1  wherein said photopolymerizable composition is selected from the group consisting of liquids, gels, and thermoplastic layers.  
     
     
         12 . The method according to  claim 1  wherein said photopolymerizable composition provides a continuous layer.  
     
     
         13 . The method according to  claim 1  wherein said photopolymerizable composition provides a discontinuous layer.  
     
     
         14 . The method according to  claim 1  wherein said photoinitiator of said photopolymerizable composition is selected from the group consisting of organometallic complex cations, acylphosphine oxides, platinum (II) beta-diketonate complexes, and cyanine borate catalysts.  
     
     
         15 . The method according to  claim 1  wherein said photoinitiator of said photopolymerizable composition is included in a three-component photoinitiator system comprising an iodonium salt, a sensitizer, and an electron donor.  
     
     
         16 . A method for identifying two layers, a photopolymerizable adhesive composition, and a radiation source for producing a laminated structure, said method comprising the steps of: 
 a) identifying two layers, at least one of which is colored, opaque, or reflective and is transmissive to actinic radiation in an identified spectral region having one or more wavelengths greater than 400 nm and up to 1200 nm, with the proviso that when said raditaion transmissive layer is colored or opaque it is essentially free of cellulosic and olefinic functionality,    b) identifying a photopolymerizable composition to be disposed between said layers comprising a photopolymerizable moiety and a photoinitiator therefor that absorbs radiation in said identified spectral region of said radiation transmissive layer, and    c) identifying a radiation source that provides actinic radiation in the identified spectral region of said radiation transmissive layer and in the radiation absorbing wavelengths of said photoinitiator,    whereby directing said actinic radiation, on demand, through said radiation transmissive layer, for less than two minutes to effect polymerization of said photopolymerizable composition produces a laminated structure.    
     
     
         17 . A method of laminating a structure comprising the steps of 
 a) providing a structure comprising at least two layers and a photopolymerizable adhesive composition between said layers, 
 1) at least one of said layers being one or both of (a) a reflective layer and (b) a layer incorporated in an electronic component, said layer being transmissive to actinic radiation in an identified spectral region having one or more wavelengths greater than 400 nm and up to 1200 nm,  
 2) said photopolymerizable composition comprising a photopolymerizable moiety and a photoinitiator therefor that absorbs actinic radiation in said identified spectral region of said radiation transmissive layer, said photopolymerizable moiety being polymerizable in a hydrosilation, cationic, or free radical polymerization process,  
   b) directing actinic radiation within said identified spectral region through said radiation transmissive layer and into said photopolymerizable composition for less than 2 minutes to cure said photopolymerizable composition,    whereby said resulting polymerized composition adheres to said layers and provides a laminated structure.    
     
     
         18 . The method according to  claim 17  wherein said layer is selected from the group consisting of alumina, polyimide, FR4, and BT epoxy.  
     
     
         19 . The method according to  claim 17  wherein said layer further comprises one or more layers of a colored solder mask or colored coating.  
     
     
         20 . The method according to  claim 17  wherein said laminated structure is a data storage disk.  
     
     
         21 . The method according to  claim 17  wherein said transmission layer further comprises metallized regions.  
     
     
         22 . The method according to  claim 17  wherein said transmissive reflective layer is selected from the group consisting of metallized films, multilayer optical films, and retroreflective films.  
     
     
         23 . The method according to  claim 17  wherein said laminated structure is selected from the group consisting of multilayer and tamper-evident documents.