Method for manufacturing a low-k layer

Abstract

Disclosed herein is a method of forming a low-k layer. The method includes the following steps. Tetraalkoxysilane, ethanol, tetraalkylammonium hydroxide and water are mixed in a molar ratio between 1:0.1:0.1:5 and 1:10:0.5:36 to form a first mixture. The first mixture is heated for a period of less than about 36 hours to form a second mixture containing a plurality of non-crystalline silicon-containing particles, wherein each of the non-crystalline silicon-containing particles has a particle size of smaller than about 10 nm. Subsequently, a surfactant is added to the second mixture to form a colloid solution, in which the surfactant has a concentration of about 1-20% by weight of the colloid solution. The colloid solution is coated on a substrate and thereby forming a colloid layer thereon. Then, the colloid layer is heated at a condition sufficient to transform the colloid layer into the low-k layer.

What is claimed is: 
     
         1 . A low-k layer, having a dielectric constant of less than 2 and without a zeolite structure therein, prepared by a process comprising the steps of:
 (a) mixing tetraalkoxysilane, ethanol, tetraalkylammonium hydroxide and water in a molar ratio between 1:4:0.3:8 and 1:10:0.4:16 to form a first mixture;   (b) heating the first mixture for a period of less than about 36 hours to form a second mixture containing a plurality of non-crystalline silicon-containing particles, wherein each of the non-crystalline silicon-containing particles has a particle size of smaller than about 10 nm;   (c) adding a surfactant to the second mixture to form a colloid solution, wherein the surfactant has a concentration of about 1-20% by weight of the colloid solution;   (d) coating the substrate with the colloid solution and thereby forming a colloid layer thereon; and   (e) heating the colloid layer at a condition sufficient to transforming the colloid layer into the low-k layer.   
     
     
         2 . The low-k layer according to  claim 1 , wherein the process further comprises a step (f) of modifying a surface of the low-k layer to be hydrophobic. 
     
     
         3 . The low-k layer according to  claim 2 , wherein the step (f) comprises contacting the low-k layer with a hexamethyldisilane solution. 
     
     
         4 . The low-k layer according to  claim 1 , wherein the process further comprises a step of adding a solvent to the second mixture or the colloid solution prior to, after or at the same time of the step (c). 
     
     
         5 . The low-k layer according to  claim 4 , wherein the solvent comprises ethanol. 
     
     
         6 . The low-k layer according to  claim 1 , wherein the step (a) is performed at a temperature of about 20-40° C. for a period of about 1-12 hours. 
     
     
         7 . The low-k layer according to  claim 1 , wherein the tetraalkoxysilane of the step (a) is tetraethylorthosilicate. 
     
     
         8 . The low-k layer according to  claim 1 , wherein the tetraalkylammonium hydroxide of the step (a) is tetrapropyl ammonium hydroxide. 
     
     
         9 . The low-k layer according to  claim 1 , wherein the low-k layer has a hardness of greater than 1 GPa and a modulus of elasticity of greater than 10 GPa. 
     
     
         10 . The low-k layer according to  claim 1 , wherein the step (b) comprises heating the first mixture at a temperature of about 80-200° C. for a period of about 4-36 hours by a hydrothermal method. 
     
     
         11 . The low-k layer according to  claim 1 , wherein the step (d) is performed by spin-coating. 
     
     
         12 . The low-k layer according to  claim 1 , wherein the step (e) comprises subjecting the colloid layer to an environment at a temperature of about 20-200° C. for a period of about 0.5-5 hours to remove the water and ethanol from the colloid layer. 
     
     
         13 . The low-k layer according to  claim 1 , wherein the step (e) comprises calcining the colloid layer at a temperature of about 400-600° C. in the presence of air. 
     
     
         14 . The low-k layer according to  claim 1 , wherein the concentration of the surfactant in step (c) is about 3-12% by weight of the colloid solution. 
     
     
         15 . The low-k layer according to  claim 14 , wherein the surfactant comprises TWEEN 80™. 
     
     
         16 . The low-k layer according to  claim 1 , wherein the low-k layer has a thickness of less than 500 nm. 
     
     
         17 . The low-k layer according to 16, wherein the thickness of the to layer is about 150-350 nm.