Compositions for Dissolution of Low-K Dielectric Films, and Methods of Use

Abstract

An improved composition and method for cleaning the surface of a semiconductor wafer are provided. The composition can be used to selectively remove a low-k dielectric material such as silicon dioxide, a photoresist layer overlying a low-k dielectric layer, or both layers from the surface of a wafer. The composition is formulated according to the invention to provide a desired removal rate of the low-k dielectric and/or photoresist from the surface of the wafer. By varying the fluorine ion component, and the amounts of the fluorine ion component and acid, component, and controlling the pH, a composition can be formulated in order to achieve a desired low-k dielectric removal rate that ranges from slow and controlled at about 50 to about 1000 angstroms per minute, to a relatively rapid removal of low-k dielectric material at greater than about 1000 angstroms per minute. The composition can also be formulated to selectively remove a photoresist layer, leaving the underlying low-k dielectric layer essentially intact.

1 . An aqueous composition, comprising an inorganic fluorine compound and an organic acid in a ratio of about 1:2 (v/v) effective to remove organic material and dielectric material to render an oxide-free substrate. 
     
     
         2 . An aqueous composition, comprising an about 1:2 (v/v) ratio of an inorganic fluorine compound and an organic acid and effective to remove organic material and dielectric material to render a hydrophobic substrate. 
     
     
         3 . An aqueous composition, comprising effective amounts of an inorganic fluorine compound at about 30-40% by volume and organic acid at about 60-70% by volume to remove organic material and dielectric material to render a substrate hydrophobic, the % by volume based on the total volume of the composition. 
     
     
         4 . An aqueous composition, comprising about 30-40% by volume of an inorganic fluorine compound with a balance of the total volume of the composition up to about 70% by volume organic acid, effective to remove organic material and dielectric material to render a substrate hydrophobic, the % by volume based on the total volume of the composition 
     
     
         5 . An aqueous composition, comprising about 30-40% by volume inorganic fluorine compound and about 60-70% by volume organic acid and a pH of about 3-4, and effective to remove a photoresist layer and at least a portion of an underlying dielectric material at about 50-1000 angstroms per minute, the % by volume based on the total volume of the composition. 
     
     
         6 . An aqueous composition, comprising an inorganic fluorine compound and an organic acid in a ratio of about 1:2 (v/v), the solution having a pH of about 3-4, and effective to remove a photoresist layer and at least a portion of an underlying dielectric material at about 50-1000 angstroms per minute. 
     
     
         7 . An aqueous composition, comprising an inorganic fluorine compound and a major amount of an organic acid, wherein when applied to a substrate, the composition removes substantially all dielectric and organic material from the substrate to provide an oxide-free, hydrophobic surface. 
     
     
         8 . An aqueous composition, consisting essentially of about 30-40% by volume inorganic fluorine compound and about 60-70% by volume organic acid and a pH of about 3-4, and effective to remove organic material and dielectric material from a substrate, the % by volume based on the total volume of the composition. 
     
     
         9 . The composition of  claim 2 , wherein the inorganic fluorine compound comprises hydrofluoric acid. 
     
     
         10 . The composition of  claim 2 , wherein the inorganic fluorine compound is selected from the group consisting of hydrofluoric acid and ammonium fluoride. 
     
     
         11 . The composition of  claim 2 , wherein the organic material comprises a photoresist material. 
     
     
         12 . The composition of  claim 2 , wherein the dielectric material comprises a trimethylsilane low k dielectric or dimethylsilane low-k dielectric. 
     
     
         13 . The composition of  claim 3 , effective to remove the dielectric and organic material at a rate of about 400-600 angstroms per minute. 
     
     
         14 . The composition of  claim 3 , wherein the inorganic fluorine compound comprises hydrofluoric acid. 
     
     
         15 . The composition of  claim 3 , wherein the inorganic fluorine compound is selected from the group consisting of hydrofluoric acid and ammonium fluoride. 
     
     
         16 . The composition of  claim 3 , wherein the organic acid is an about 20-60% aqueous solution. 
     
     
         17 . The composition of  claim 3 , wherein the organic acid is selected from the group consisting of citric acid, acetic acid, ascorbic acid, formic acid, propionic acid, butyric acid, isobutyric acid, benzoic acid, gluconic acid, malic acid, malonic acid, oxalic acid, succinic acid, tartaric acid, and gallic acid. 
     
     
         18 . The composition of  claim 3 , having a pH of about 3-4. 
     
     
         19 . The composition of  claim 3 , wherein the organic material comprises a photoresist material. 
     
     
         20 . The composition of  claim 3 , wherein the dielectric material comprises a trimethylsilane low k dielectric or dimethylsilane low-k dielectric.