Alkali-soluble resin and negative-type photosensitive resin composition comprising the same

Abstract

An alkali-soluble resin is provided. The alkali-soluble resin is prepared using a polyfunctional thiol compound as a chain transfer agent. The alkali-soluble resin has a lower viscosity than a resin having the same molecular weight. Further provided is a negative-type photosensitive resin composition comprising the alkali-soluble resin as a binder resin. The use of the alkali-soluble resin lowers the overall viscosity of the photosensitive resin composition to effectively reduce the height of a stepped portion of a photoresist pattern using a small amount of the photosensitive resin composition.

1 . An alkali-soluble resin composition, comprising an acid group-containing monomer, a monomer polymerizable with the acid group-containing monomer, and a polyfunctional thiol compound as a chain transfer agent. 
   
   
       2 . The composition according to  claim 1 , wherein the polyfunctional thiol compound is an aliphatic or aromatic one. 
   
   
       3 . The composition according to  claim 2 , wherein the polyfunctional thiol compound is selected from the group consisting of glycol dimercaptoacetate, trimethylolpropane tris(3-mercaptopropionate), trimethylolpropane tris(2-mercaptopropionate), trimethylolpropane tris(2-mercaptoacetate), pentaerythritol tetrakis(thioglycolate), pentaerythritol tetrakis(2-mercaptoacetate), allyl mercaptan, ethylene glycol dimercaptopropionate, trithiocyanuric acid (1,3,5-triazine-2,4,6-trithiol), 3-dithiophenyl ether, 1,3-dimethylthiomethylbenzene, pentaerythritol tetrakismercaptop-ropionate, 1,4-butanedithiol, 1,5-pentanedithiol, 1,6-pentanedithiol, tetra-methylene glycol bismercaptopropionate, 1,6-hexyldiol bismercaptopropionate, pentaerythritol bismercaptopropionate, pentaerythritol trismercaptopropionate, trimethylolpropane bismercaptopropionate, trimethylolpropane trismercaptopropionate, dipentaerythritol trismercaptopropionate, sorbitol trismercaptopropionate, sorbitol tetrakismercaptopropionate, sorbitol hexakismercaptopropionate, dithioethyl terephthalate, 1,6-hexanediol dithioethyl ether, 1,5-pentanediol dithioethyl ether, pentaerythritol tetra(β-thioethyl ether), and mixtures thereof. 
   
   
       4 . The composition according to  claim 1 , wherein the polyfunctional thiol compound is present in an amount of 0.1 to 10% by weight, based on the total solids content of all monomers. 
   
   
       5 . The composition according to  claim 1 , wherein the acid group-containing monomer is selected from the group consisting of (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, monomethyl maleic acid, isoprene sulfonic acid, styrene sulfonic acid, 5-norbornene-2-carboxylic acid, mono-2-((meth)acryloyloxy)ethyl phthalate, mono-2-((meth)acryloyloxy)ethyl succinate, co-carboxy polycaprolactone mono(meth)acrylate, and mixtures thereof. 
   
   
       6 . The composition according to  claim 1 , wherein the monomer polymerizable with the acid group-containing monomer is selected from the group consisting of unsaturated carboxylic acid ester monomers, aromatic vinyl monomers, unsaturated ether monomers, N-vinyl tertiary amine monomers, unsaturated imide monomers, maleic anhydride monomers, and mixtures thereof. 
   
   
       7 . The composition according to  claim 1 , wherein the acid group-containing monomer is reacted with the monomer polymerizable with the acid group-containing monomer in a weight ratio of 5:95 to 45:55. 
   
   
       8 . An alkali-soluble resin prepared from the composition according to  claim 1 . 
   
   
       9 . The alkali-soluble resin according to  claim 8 , wherein the resin has an acid value
 50 to 150 KOH mg/g and a weight average molecular weight of 5,000 to 20,000 g/mol on a polystyrene basis.   
   
   
       10 . The alkali-soluble resin according to  claim 8 , wherein the resin has a 20-30% lower viscosity than a resin having the same molecular weight. 
   
   
       11 . A negative-type photosensitive resin composition comprising the alkali-soluble resin according to  claim 8 . 
   
   
       12 . The composition according to  claim 11 , wherein the alkali-soluble resin is present in an amount of 1 to 30% by weight, based on the total weight of the composition. 
   
   
       13 . The composition according to  claim 11 , wherein the composition has a viscosity of 3 to 10 cps.