Method for Pore Sealing of Porous Materials Using Polyimide Langmuir-Blodgett Film

Abstract

Method for pore sealing a porous substrate, comprising: forming a continuous monolayer of a polyimide precursor on a liquid surface, transferring said polyimide precursor monolayer onto the porous substrate with the Langmuir-Blodgett technique, and imidization of the transferred polyimide precursor monolayers, thereby forming a polyimide sealing layer on the porous substrate. Porous substrate having at least one surface on which a sealing layer is provided to seal pores of the substrate, wherein the sealing layer is a polyimide having a thickness of a few monolayers and wherein there is no penetration of the polyimide into the pores.

1 . (canceled) 
     
     
         2 . A porous substrate having at least one surface on which a sealing layer is provided to seal pores of the substrate,
 wherein the porous substrate is an ultra-low κ dielectric material having a dielectric constant κ lower than 2.3 and the porous substrate has a pore size of 1 to 5 nm, and   wherein the sealing layer includes an imidized continuous monolayer of a polyimide precursor.   
     
     
         3 . The porous substrate of  claim 2 , wherein the sealing layer has a thickness lower than 5 nm. 
     
     
         4 . The porous substrate of  claim 2 , wherein the polyimide precursor is polyamic acid alkylamine salt. 
     
     
         5 . The porous substrate of  claim 2 , wherein the sealing layer does not penetrate into pores of the porous substrate. 
     
     
         6 . The porous substrate of  claim 2 , wherein the dielectric constant κ is lower than 2.1. 
     
     
         7 . The porous substrate of  claim 2 , wherein the porous substrate has an average pore size of 2 nm. 
     
     
         8 . The porous substrate of  claim 2 , wherein the substrate is a porous organosilicate. 
     
     
         9 . The porous substrate of  claim 8 , wherein the porous organosilicate comprises SiOCH material having a κ-value of 2.3 and an average pore size of 2 nm. 
     
     
         10 . The porous substrate of  claim 2 , wherein the imidized continuous monolayer of the polyimide precursor was formed on a liquid surface. 
     
     
         11 . The porous substrate of  claim 10 , wherein the imidized continuous monolayer of the polyimide precursor was transferred onto the porous substrate using a Langmuir-Blodgett technique.