Processing method and processing apparatus

Abstract

A processing method of subjecting at least two stacked films, which comprise a first film and a second film of a target object to be processed, to a removing process by wet etching comprises bringing a first process liquid into contact with the first film of the target object, thereby etching the first film, determining whether the first film has been removed or not, switching the first process liquid to a second process liquid differing in a condition from the first process liquid when it has been determined that the first film has been removed, and bringing the second process liquid into contact with the second film, thereby etching the second film.

1 . A processing method of subjecting at least two stacked films, which comprise a first film and a second film of a target object to be processed, to a removing process by wet etching, the method comprising: 
 bringing a first process liquid into contact with the first film of the target object, thereby etching the first film;    determining whether the first film has been removed or not;    switching the first process liquid to a second process liquid differing from the first process liquid in a condition when it is determined that the first film has been removed; and    bringing the second process liquid into contact with the second film, thereby etching the second film.    
   
   
       2 . The processing method according to  claim 1 , wherein the first process liquid dissolves both the first film and the second film.  
   
   
       3 . The processing method according to  claim 1 , wherein the determining whether the first film has been removed or not is performed by measuring the concentration of a prescribed substance in the first process liquid, which has been brought into contact with the target object.  
   
   
       4 . The processing method according to  claim 3 , wherein it is determined that the first film has been removed at the time when the amount of the component of the first film in the first process liquid or the rate of increase in the component of the first film in the first process liquid have become lower than the set values.  
   
   
       5 . The processing method according to  claim 3 , wherein it is determined that the first film has been removed at the time when the amount of the component of the second film in the first process liquid has increased to exceed the set value.  
   
   
       6 . The processing method according to  claim 1 , wherein the first film is a high dielectric constant material, the second film is an interfacial film of silicon oxide (SiO 2 ) or silicon oxynitride (SiO x N y ), and the target object comprises a structure including a gate insulating film and a gate electrode disposed on a silicon substrate in this order wherein the gate insulating film has a two-layer structure consisting of a second film formed on a silicon substrate and the first film formed on the second film.  
   
   
       7 . The processing method according to  claim 1 , wherein the first process liquid and the second process liquid differ from each other in chemical species.  
   
   
       8 . The processing method according to  claim 1 , wherein the first process liquid and the second process liquid are formed of chemical liquids of the same kind and differ from each other in the concentration of the component and/or the pH value.  
   
   
       9 . The processing method according to  claim 1 , wherein the first process liquid and the second process liquid are formed of chemical liquids of the same kind and differ from each other in temperature.  
   
   
       10 . A processing method of subjecting at least two stacked films, which comprise a first film and a second film of a target object, to a removing process by wet etching, the method comprising: 
 Bringing a first process liquid into contact with the first film of the target object, the first process liquid being capable of etching the first film with a high etching selectivity relative to the second film;    determining whether the first film has been removed or not;    switching the first process liquid to a second process liquid differing from the first process liquid in a condition and capable of etching the second film with a high selectivity relative to the first film when it has been determined that the first film has been removed; and    bringing the second process liquid into contact with the second film, thereby etching the second film.    
   
   
       11 . The processing method according to  claim 10 , wherein the first process liquid dissolves both the first film and the second film.  
   
   
       12 . The processing method according to  claim 10 , wherein the determining whether the first film has been removed or not is performed by measuring the concentration of a prescribed substance in the first process liquid, which has been brought into contact with the target object.  
   
   
       13 . The processing method according to  claim 12 , wherein it is determined that the first film has been removed at the time when the amount of the component of the first film in the first process liquid or the rate of increase in the component of the first film in the first process liquid have become lower than the set values.  
   
   
       14 . The processing method according to  claim 12 , wherein it is determined that the first film has been removed at the time when the amount of the component of the second film in the first process liquid has increased to exceed the set value.  
   
   
       15 . The processing method according to  claim 10 , wherein the first film is a high dielectric constant material, the second film is an interfacial film of silicon oxide (SiO 2 ) or silicon oxynitride (SiO x N y ), and the target object comprises a structure including a gate insulating film and a gate electrode disposed on a silicon substrate in this order wherein the gate insulting film has a two-layer structure consisting of a second film formed on a silicon substrate and the first film formed on the second film.  
   
   
       16 . The processing method according to  claim 10 , wherein the first process liquid and the second process liquid differ from each other in chemical species.  
   
   
       17 . The processing method according to  claim 10 , wherein the first process liquid and the second process liquid are formed of chemical liquids of the same kind and differ from each other in the concentration of the component and/or the pH value.  
   
   
       18 . The processing method according to  claim 10 , wherein the first process liquid and the second process liquid are formed of chemical liquids of the same kind and differ from each other in temperature.  
   
   
       19 . A processing apparatus for removing by a wet etching at least two stacked films, which comprise a first film and a second film of a target object to be processed, the apparatus comprising: 
 a housing section housing the target object;    a first process liquid supply section for supplying the first process liquid onto the target object housed in the housing section, thereby bringing the first process liquid into contact with the first film for proceeding the etching of the first film;    a second process liquid supply section for supplying the second process liquid differing in the condition from the first process liquid onto the target object housed in the housing section, thereby bringing the second process liquid into contact with the second film for proceeding the etching of the second film;    a detecting section for detecting the removed state of the first film;    a switching section for switching the process liquid that is brought into contact with the target object from the first process liquid to the second process liquid; and    a control section for determining whether the first film has been removed on the basis of the detected value in the detecting section and, when it has been determined that the first film has been removed, for transmitting to the switching section an instruction to switch the process liquid that is brought into contact with the target object from the first process liquid to the second process liquid.    
   
   
       20 . The processing apparatus according to  claim 19 , wherein the first process liquid is capable of etching the first film with a high etching selectivity relative to the second film, and the second process liquid is capable of etching the second film with a high etching selectivity relative to the first film.  
   
   
       21 . The processing apparatus according to  claim 19 , wherein the detecting section measures the concentration of a prescribed substance in the first process liquid in contact with the target object.  
   
   
       22 . The processing apparatus according to  claim 19 , wherein the control section determines that the first film has been removed at the time when the amount of the component of the first film in the first process liquid, which is detected by the detecting section, or the rate of increase in the component of the first film in the first process liquid, which is detected by the detecting section, has been made smaller or lower that the set value.  
   
   
       23 . The processing apparatus according to  claim 21 , wherein the control section determines that the first film has been removed at the time when the amount of the component of the second film in the first process liquid, which is detected by the detecting section, or the rate of increase in the component of the second film in the first process liquid, which is detected by the detecting section, has been made larger or higher that the set value.  
   
   
       24 . The processing apparatus according to  claim 19 , wherein the first process liquid supply section and the second process liquid supply section supply the first process liquid and the second process liquid, respectively, onto the surface of the target object.  
   
   
       25 . The processing apparatus according to  claim 19 , wherein the first process liquid supply section and the second process liquid supply section supply the first process liquid and the second process liquid, respectively, into the housing section such that the target object housed in the housing section is dipped in the first process liquid and the second process liquid, respectively.  
   
   
       26 . A computer program including a soft ware which, when executed, causes the computer to control a processing apparatus for removing by a wet etching at least two stacked films, which comprise a first film and a second film of a target object to be processed, wherein the soft ware causes the computer to execute the operations of: 
 bringing a first process liquid into contact with the first film of the target object, thereby etching the first film;    determining whether the first film has been removed or not;    switching the first process liquid to a second process liquid differing in a condition from the first process liquid when it has been determined that the first film has been removed; and    bringing the second process liquid into contact with the second film, thereby etching the second film.    
   
   
       27 . A storage medium that can be read by a computer, the storage medium including a soft ware which, when executed, causes the computer to control a processing apparatus for removing by a wet etching at least two stacked films, which comprise a first film and a second film of a target object to be processed, wherein the soft ware causes the computer to execute the operations of: 
 bringing a first process liquid into contact with the first film of the target object, thereby etching the first film;    determining whether the first film has been removed or not;    switching the first process liquid to a second process liquid differing in a condition from the first process liquid when it has been determined that the first film has been removed; and    bringing the second process liquid into contact with the second film, thereby etching the second film.