Selective plasma etching process for aluminum oxide patterning

Abstract

This invention relates to a method for the selective and directed plasma etching of aluminum oxide, in which a mixture having the following constituents is used for etching: a. a polymerizing gas comprising at least partially unsaturated, perfluorinated hydrocarbon compounds; b. optionally a compound having the formula CH x F y , where x=1-3 and y=4-x; c. oxygen; and d. a suitable carrier gas; and this mixture as a plasma, is brought into contact with the aluminum oxide to be etched.

1 . Method for the selective and directed plasma etching of aluminum oxide, having the step of etching with a mixture having the following constituents: 
 a. a polymerizing gas comprising at least partially unsaturated, perfluorinated hydrocarbon compounds;    b. optionally a compound having the formula CH x F y , where x=1, 2 or 3 and y=4-x;    c. oxygen; and    d. a suitable carrier gas;    and this mixture as a plasma, is brought into contact with the aluminum oxide to be etched.    
     
     
         2 . Method according to  claim 1 , wherein C 4 F 6  and/or C 5 F 8  are used as the at least partially unsaturated, perfluorinated hydrocarbon compounds for gas a.  
     
     
         3 . Method according to  claim 1 , wherein CH 2 F 2  is used as compound having the formula CH x F y .  
     
     
         4 . Method according to  claim 1 , wherein argon is used as carrier gas.  
     
     
         5 . Method according to  claim 1  wherein the volumetric ratio of the constituents a:b:c:d is approximately 0.7-1.3:0-1:0.5-2:5-200, preferably approximately 0.8-1.2:0.4-0.8:0.6-1.4:10-100.  
     
     
         6 . Method according to  claim 1  wherein the following combination of constituents is used: 
 a: C 4 F 6 ;    b: CH 2 F 2 ;    c: O 2 ;    d: Ar.    
     
     
         7 . Method according to  claim 1 , wherein the constituents a. to d. are present in approximately the following ratios: a:b:c:d=1:0.6:0.8:20.  
     
     
         8 . Method according to  claim 1 , wherein the process pressure during the etching of aluminum oxide is approximately 15 to approximately 100 mtorr, preferably approximately 40 to approximately 80 mtorr.  
     
     
         9 . Method according to  claim 1 , wherein the method is effected as part of the fabrication of a semiconductor structure in order to produce an etched aluminum oxide layer.  
     
     
         10 . Method according to  claim 9 , wherein the etching for producing an etched aluminum oxide layer is followed by a patterning of an underlying layer, preferably made of silicon, silicon nitride or silicon oxide, the etched aluminum oxide layer being used as a mask.  
     
     
         11 . Use of the method according to  claim 1 , for controlled removal of aluminum oxide on Si, silicon oxide, silicon oxynitride or silicon nitride.  
     
     
         12 . Use of the method according to  claim 1 , for etching barrier layers or tunnel layers made of aluminum oxide that occur in magnetic memories or in hard disk read heads.  
     
     
         13 . Use of the method according to  claim 1  in semiconductor manufacturing, in particular in the course of contact hole etching.  
     
     
         14 . Method for fabricating an aluminum oxide hard mask, having the steps of: 
 a. providing an aluminum oxide layer on a substrate, preferably a silicon, silicon nitride, silicon oxynitride and/or silicon oxide substrate;    b. providing a mask on the aluminum oxide layer; and    c. etching the aluminum oxide layer by the method according to  claim 1.