Photoimageable waveguide composition and waveguide formed therefrom

Abstract

Provided are photodefinable compositions suitable for use in forming an optical waveguide. The compositions include a silsesquioxane polymer having polymerized units of the formula (R 1 SiO 1.5 ) and (R 2 SiO 1.5 ), wherein R 1 and R 2 are different and are substituted or unsubstituted organic side chain groups and are free of hydroxy groups, and two or more functional end groups, and a photoactive component. The solubility of the silsesquioxane polymer is altered upon exposure to actinic radiation such that the composition is developable in an aqueous developer solution. Also provided are methods of forming an optical waveguide with the inventive compositions, optical waveguides, and electronic devices including one or more optical waveguide.

1 - 40 . (canceled)  
   
   
       41 . A negative-acting photodefinable composition suitable for use in forming an optical waveguide, comprising: 
 a polymer, comprising: 
 polymerized units of the formula (RSiO 1.5 ), wherein R is a substituted or unsubstituted organic side chain group, all said polymerized units are free of hydroxy groups, and said polymerized units comprise polymerized units of the formula (R 1 SiO 1.5 ) and (R 2 SiO 1.5 ), wherein R 1  is a substituted or unsubstituted aromatic group and R 2  is a substituted or unsubstituted aliphatic group, and R 1  and R 2  are free of hydroxy groups; and  
 two or more functional end groups; and  
   a photoactive component,    wherein the two or more functional end groups comprise one or more hydroxy groups present in an amount of from 0.5 to 15 mole %, based on the polymer, and wherein the solubility of the silsesquioxane polymer is altered upon exposure to actinic radiation such that the composition is developable in an aqueous developer solution.    
   
   
       42 . The negative-acting photodefinable composition according to  claim 41 , wherein R 1  is a phenyl group and R 2  is a methyl group.  
   
   
       43 . The negative-acting photodefinable composition according to  claim 41 , wherein the silsesquioxane polymer further comprises a unit of the formula ((R 3 ) 2 SiO), wherein R 3  is a substituted or unsubstituted organic group.  
   
   
       44 . The negative-acting photodefinable composition according to  claim 41 , wherein the photoactive component is a photoacid generator.  
   
   
       45 . The negative-acting photodefinable composition according to  claim 41 , further comprising a cross-linking agent.  
   
   
       46 . The negative-acting photodefinable composition according to  claim 41 , further comprising a flexibilizer.  
   
   
       47 . A method of forming an optical waveguide, comprising: 
 (a) depositing over a substrate a layer of the negative-acting photodefinable composition according to claim  1 , wherein the layer has a higher refractive index than the substrate;    (b) exposing a portion of the layer to actinic radiation; and    (c) developing the exposed layer, thereby forming a core structure.    
   
   
       48 . The method according to  claim 47 , wherein the developing is conducted by contacting the exposed layer with an aqueous developer solution.  
   
   
       49 . The method according to  claim 47 , further comprising depositing a cladding layer over the core structure, wherein the cladding layer comprises a silsesquioxane polymer.  
   
   
       50 . The method according to  claim 47 , wherein R 1  is a phenyl group and R 2  is a methyl group.  
   
   
       51 . The method according to  claim 47 , wherein the silsesquioxane polymer further comprises a polymerized unit of the formula ((R 3 ) 2 SiO), wherein R 3  is a substituted or unsubstituted organic group.  
   
   
       52 . The method according to  claim 47 , wherein the photoactive component is a photoacid generator.  
   
   
       53 . The method according to  claim 47 , wherein the photodefinable composition further comprises a cross-linking agent.  
   
   
       54 . The method according to  claim 47 , wherein the photodefinable composition further comprises a flexibilizer.  
   
   
       55 . An optical waveguide, comprising a core and a cladding, wherein the core is formed from the photodefinable composition according to  claim 41 .  
   
   
       56 . An electronic device, comprising one or more waveguides according to  claim 55 .  
   
   
       57 . A printed wiring board, comprising one or more waveguides according to  claim 55.