provide a liquid coating composition can be exemplified by but are not limited to aliphatic hydrocarbon solvents such as hexane aromatic hydrocarbon solvents such as anisole mesitylene and xylene ketone based solvents such as methyl isobutyl ketone 1 methyl 2 pyrrolidinone and acetone ether based solvents such as cyclohexanone tetrahydrofuran and isopropyl ether acetate based solvents such as ethyl acetate butyl acetate and propylene glycol methyl ether acetate alcohol based solvents such as isopropyl alcohol and butyl alcohol amide based solvents such as dimethylacetamide and dimethylformamide silicon based solvents and mixtures thereof in the preparation of the liquid coating composition the organic solvent should be used in an amount sufficient to apply the solid components including the siloxane based resin and the porogen evenly to the surface of a wafer thus the organic solvent should amount to 20 99 9 wt preferably 70 95 wt of the liquid coating composition if the organic solvent content of the liquid coating composition is less than 20 wt part of the siloxane based resin remains undissolved on the other hand if the organic solvent content is more than 99 9 wt the final resinous film is as thin as 1000 u00e5 or less in the present invention the liquid coating composition thus prepared can be applied to a silicon wafer according to various coating methods well known in the art non limiting examples of the coating method useful in the present invention include spin coating dip coating spray coating flow coating and screen printing while spin coating is most preferred the present invention can be more clearly understood with referring to the following examples it should be understood that the following examples are not intended to restrict the.