Method of optimizing seasoning recipe for etch process

Abstract

A method for optimizing a seasoning recipe for a dry etch process. The method includes setting a critical value of reproducibility, a main etch recipe, and a preliminary seasoning recipe. A test wafer is then etched using the preliminary seasoning recipe in a dry etch chamber. Next, a main etch process is performed with respect to at least 10 run wafers in the dry etch chamber using the main etch recipe and an end-point detection time for each wafer is determined. An initial dispersion and a standard deviation are then determined using the determined end-point detection times. The critical value of reproducibility is then compared to the initial dispersion. If the initial dispersion is equal to or less than the critical value of reproducibility, the preliminary seasoning recipe is used as the seasoning recipe, otherwise the preliminary seasoning recipe is modified and the process is repeated until an optimal seasoning recipe is determined.

1 . A program storage device readable by machine, tangibly embodying a program of instructions executable by the machine to perform method steps for optimizing a seasoning recipe for an etching process, the method steps comprising: 
 (a) selecting a critical value of reproducibility;    (b) selecting a main etch recipe;    (c) selecting a preliminary seasoning recipe;    (d) etching a test wafer using the preliminary seasoning recipe in a dry etch chamber;    (e) performing a main etch process for a plurality of run wafers in the dry etch chamber using the main etch recipe, and determining an end-point detection time of each run wafer;    (f) determining an initial dispersion and a standard deviation using the determined end-point detection times;    (g) comparing the initial dispersion to the critical value of reproducibility; and    (h) selecting the preliminary seasoning recipe as a seasoning recipe for the etch process, if the initial dispersion is less than or equal to the critical value of reproducibility.    
   
   
       2 . The program storage device of  claim 1 , further comprising instructions for changing the preliminary seasoning recipe and repeating steps (c)-(h), if the initial dispersion is greater than the critical value of reproducibility.  
   
   
       3 . The program storage device of  claim 1 , wherein the critical value of reproducibility is proportional to the standard deviation.  
   
   
       4 . The program storage device of  claim 1 , wherein the critical value of reproducibility is about 1 to 6 time(s) the standard deviation.  
   
   
       5 . The program storage device of  claim 1 , wherein the initial dispersion is determined as an absolute value of the difference between the end-point detection time of a first run wafer and the end-point detection time of a third run wafer.  
   
   
       6 . The program storage device of  claim 5 , wherein the standard deviation is determined using the end-point detection times of a fourth run wafer through at least a tenth run wafer.  
   
   
       7 . The program storage device of  claim 1 , wherein the main etch recipe and the preliminary seasoning recipe are selected to use the same etch gas.