Etching composition and use thereof with feedback control of HF in BEOL clean

Abstract

A process for providing an aqueous back-end-of-line (BEOL) clean with feed-back control to monitor the active component of HF in the clean, for a wiring/interconnect of a reactive ion etched semiconductor device, comprising: subjecting the reactive ion etched semiconductor device to a post metal RIE clean using an etchant composition comprising about 0.01 to about 15 percent by weight of sulfuric acid; about 0.1 to about 100 ppm of a fluoride containing compound; and a member selected from the group consisting of about 0.01 to about 20 percent by weight of hydrogen peroxide or about 1 to about 30 ppm of ozone, comprising: a) mixing water, sulfuric acid and hydrogen peroxide in a mixing tank, b) mixing HF directly into the mixing tank or adding HF into a separate vessel for wafer processing, either before, during or after the mixture water, sulfuric acid and hydrogen peroxide as a mixture is transported to the separate tank for wafer processing; c) taking a sample comprising HF from the mixing tank or HF from the wafer processing tank and sending the sample through a feedback loop; d) comparing the sample to a standard dilute solution of HF to obtain a value of HF concentration in the sample; e) inputting the value to a tank tool recipe control to cause any needed adjustment in concentration of HF to a predetermined range, either in the mixing tank or the wafer processing vessel; and f) subjecting the wiring/interconnect of the semiconductor device to etching by the etchant composition to remove sidewall polymer, polymer rails and via residue without etching conductive materials during removal of sidewall polymer, polymer rails, and via residue.

1 . A method for cleaning semiconductor devices using an etchant composition, the method comprising: 
 a) mixing water, sulfuric acid and one of hydrogen peroxide or ozone in a mixing tank;    b) mixing HF directly into said mixing tank or adding HF into a separate tank for wafer processing, either before, during or after said mixture of said water, sulfuric acid and hydrogen peroxide is transported to a tank for wafer processing; and    c) subjecting said semiconductor device to etching by said etchant composition to remove sidewall polymer, polymer rails and via residue without etching conductive materials during removal of sidewall polymer, polymer rails, and via residue,    said etchant composition comprising: 
 (i) about 0.01 to about 15 percent by weight of sulfuric acid;  
 (ii) about 0.1 to about 100 ppm of a fluoride containing compound; and  
 (iii) a member selected from the group consisting of about 0.1 to about 20 percent by weight of hydrogen peroxide or about 1 to about 30 ppm of ozone.  
   
     
     
         2 . The process of  claim 1  wherein said fluoride containing compound comprises hydrofluoric acid.  
     
     
         3 . The process of  claim 1  wherein said etchant composition comprises about 0.01 to about 20 percent by weight of hydrogen peroxide.  
     
     
         4 . The process of  claim 1  wherein said etchant composition comprises about 1 to about 30 ppm of ozone.  
     
     
         5 . The process of  claim 2  wherein said etchant composition comprises about 1 to about 10 percent by weight of sulfuric acid, about 1 to about 10 percent by weight hydrogen peroxide, and about 1 to about 50 ppm of hydrofluoric acid.  
     
     
         6 . The process of  claim 2  wherein said etchant composition comprises about 5 percent by weight of sulfuric acid, about 12 percent by weight of hydrogen peroxide and about 10 ppm of hydrofluoric acid.  
     
     
         7 . The process of  claim 1  wherein said etchant composition includes deionized water.  
     
     
         8 . A process for providing an aqueous back-end-of-line (BEOL) clean with feedback control to monitor the active component of HF in said clean, for a wiring/interconnect of a reactive ion etched semiconductor device, comprising: 
 subjecting said reactive ion etched semiconductor device to a post metal RIE clean using the etchant composition of  claim 1 , comprising: 
 a) mixing water, sulfuric acid and hydrogen peroxide in a mixing tank;  
 b) mixing HF directly into said mixing tank or adding HF into a separate vessel for wafer processing, either before, during or after said mixture water, sulfuric acid and hydrogen peroxide as a mixture is transported to said separate tank for wafer processing;  
 c) taking a sample comprising HF from said mixing tank or HF from said wafer processing tank and sending said sample through a feedback loop;  
 d) comparing said sample to a standard dilute solution of HF to obtain a value of HF concentration in said sample;  
 e) inputting said value to a tank tool recipe control to cause any needed adjustment in concentration of HF to a predetermined range, either in said mixing tank or said wafer processing vessel; and  
 f) subjecting said wiring/interconnect of said semiconductor device to etching by said etchant composition to remove sidewall polymer, polymer rails and via residue without etching conductive materials during removal of sidewall polymer, polymer rails, and via residue.  
   
     
     
         9  The process of  claim 8 , wherein said fluoride containing compound comprises hydrofluoric acid.  
     
     
         10 . The process of  claim 8 , wherein said etchant composition comprises about 0.01 to about 2.0 percent by weight of hydrogen peroxide.  
     
     
         11 . The process of  claim 8 , wherein said etchant composition comprises about 1 to about 30 ppm of ozone.  
     
     
         12 . The process of  claim 9 , wherein said etchant composition comprises about 1 to about 10 percent by weight of sulfuric acid, about 1 to about 10 percent by weight of hydrogen peroxide, and about 1 to about 100 ppm of hydrofluoric acid.  
     
     
         13 . The process of  claim 9 , wherein said etchant composition comprises about 5 percent by weight of sulfuric acid, about 12 percent by weight of hydrogen peroxide and about 10 ppm of hydrofluoric acid.  
     
     
         14 . The process of  claim 8 , wherein said etchant composition includes deionized water.  
     
     
         15 . The process of  claim 8 , wherein said separate vessel for wafer processing is a spray processor.  
     
     
         16 . The process of  claim 12  when delivered to a spin-spray processor, short times typically less than 1 minute, most preferably 20 seconds could be used when HF concentration is close to 100 ppm HF.