Single-substrate-heat-processing apparatus and method for performing reformation and crystallization

Abstract

An insulating film consisting of first and second tantalum oxide layers is formed on a semiconductor wafer. First, an amorphous first layer is formed by CVD, and a reforming process for removing organic impurities contained in the first layer is carried out. Then, an amorphous second layer is formed by CVD on the first layer. Then, a reforming process for removing organic impurities contained in the second layer is carried out by supplying a process gas containing ozone into a process chamber while heating the wafer to a temperature lower than a crystallizing temperature over a certain period. Further, within the same process chamber, the wafer is successively heated to a second temperature higher than the crystallizing temperature, followed by cooling the wafer to a temperature lower than the crystallizing temperature so as to crystallize the first and second layers simultaneously.

1 . A single-substrate-heat-processing apparatus for performing a reforming process for removing organic impurities contained in a thin film formed on a target substrate and a crystallizing process for crystallizing said thin film, said thin film being formed of a material selected from the group consisting of metal oxides, metal nitrides and metals, said apparatus comprising: 
 an airtight process chamber;    a work table arranged within said process chamber configured to place said target substrate thereon;    an exhaust mechanism configured to exhaust said process chamber;    a supply mechanism configured to supply a process gas containing oxygen atoms into said process chamber;    a heating mechanism configured to heat said thin film while said target substrate is placed on said work table; and    a control section configured to serve to control said heating mechanism such that said thin film is heated to a first temperature lower than said crystallizing temperature of said material over a first period and, then, said thin film is heated to a second temperature higher than said crystallizing temperature, followed by cooling said thin film to a temperature lower than said crystallizing temperature, said first period being longer than a second period during which said thin film has a temperature higher than said crystallizing temperature.    
     
     
         2 . The apparatus according to    claim 1   , further comprising an exciting mechanism configured to excite said process gas so as to generate active oxygen atoms that are to be supplied to said thin film.  
     
     
         3 . The apparatus according to    claim 1   , wherein said exciting mechanism includes a lamp configured to irradiate said process gas with ultraviolet rays within said process chamber.  
     
     
         4 . The apparatus according to    claim 3   , wherein said heating mechanism includes a heater configured to heat said target substrate from said work table and a lamp configured to irradiate said thin film with infrared rays from a side opposite to said work table.  
     
     
         5 . The apparatus according to    claim 4   , wherein said ultraviolet rays and said infrared rays are emitted from different lamps.  
     
     
         6 . The apparatus according to    claim 4   , wherein said heating mechanism includes a member configured to scan said thin film with said infrared rays.  
     
     
         7 . The apparatus according to    claim 4   , wherein said exciting mechanism includes a member configured to convert said process gas into a plasma.  
     
     
         8 . A film forming system for forming a crystallized thin film on a target substrate, said thin film being formed of a material selected from the group consisting of metal oxides, metal nitrides and metals, said system comprising: 
 an airtight common transfer chamber;    a transfer mechanism arranged within said common transfer chamber configured to transfer said target substrate;    a single-substrate-processing CVD apparatus connected to said common transfer chamber via a gate valve, configured to deposit an amorphous thin film by CVD on said target substrate; and    a single-substrate-heat-processing apparatus connected to said common transfer chamber configured to perform a reforming process for removing organic impurities contained in said thin film and a crystallizing process for crystallizing said thin film, said heat-processing apparatus including,    an airtight process chamber,    a work table arranged within said process chamber configured to place said target substrate thereon,    an exhaust mechanism configured to exhaust said process chamber,    a supply mechanism configured to supply a process gas containing oxygen atoms into said process chamber,    a heating mechanism configured to heat said thin film while said target substrate is placed on said work table, and    a control section configured to serve to control said heating mechanism such that said thin film is heated to a first temperature lower than said crystallizing temperature of said material over a first period and, then, said thin film is heated to a second temperature higher than said crystallizing temperature, followed by cooling said thin film to a temperature lower than said crystallizing temperature, said first period being longer than a second period during which said thin film has a temperature higher than said crystallizing temperature.    
     
     
         9 . The system according to    claim 8   , wherein said heat-processing apparatus further comprises an exciting mechanism configured to excite said process gas so as to generate active oxygen atoms that are to be supplied to said thin film.  
     
     
         10 . The system according to    claim 8   , wherein said CVD apparatus is an apparatus configured to form a metal oxide film while supplying a first process gas containing a metal element and a second process gas containing an oxidizing gas.  
     
     
         11 . A method of forming a thin film on a target substrate, said thin film being formed of a material selected from the group consisting of metal oxides, metal nitrides and metals, said method comprising: 
 depositing a thin film in an amorphous state by CVD on said target substrate;    placing said target substrate having said thin film deposited thereon on a work table arranged within an airtight process chamber;    performing a reforming process for removing organic impurities from said thin film by supplying a process gas containing oxygen atoms into said process chamber and heating over a first period said thin film formed on said target substrate placed on said work table to a first temperature lower than a crystallizing temperature of said material while exhausting said process chamber; and    performing a crystallizing process for crystallizing said thin film after said reforming process by heating said thin film formed on said target substrate placed on said work table to a second temperature higher than said crystallizing temperature, followed by cooling said thin film to a temperature lower than said crystallizing temperature, said first period being longer than a second period during which said thin film has a temperature higher than said crystallizing temperature.    
     
     
         12 . The method according to    claim 11   , wherein said process gas is excited during said reforming process to supply active oxygen atoms to said thin film.  
     
     
         13 . The method according to    claim 11   , wherein said process gas within said process chamber is irradiated with ultraviolet rays for forming said active oxygen atoms.  
     
     
         14 . The method according to    claim 13   , wherein said thin film is heated during said reforming process and said crystallizing process by heating said target substrate from said work table and by irradiating said thin film with infrared rays on a side opposite to said work table.  
     
     
         15 . The method according to    claim 14   , wherein said ultraviolet rays and said infrared rays are emitted from different lamps.  
     
     
         16 . The method according to    claim 14   , wherein said thin film is scanned with said infrared rays.  
     
     
         17 . The method according to    claim 12   , wherein said process gas is converted into a plasma for generating said active oxygen atoms.  
     
     
         18 . The method according to    claim 11   , wherein said thin film is heated from said first temperature to said second temperature at a heating rate of 30 to 100° C./sec.  
     
     
         19 . The method according to    claim 11   , wherein said material consists essentially of tantalum oxide, and said first and second temperatures are 320 to 600° C. and 700 to 800° C., respectively.  
     
     
         20 . A method of forming a thin film on a target substrate, said thin film including a first layer and a second layer formed of a material selected from the group consisting of metal oxides, metal nitrides and metals, said method comprising: 
 depositing a first layer in an amorphous state by CVD on said target substrate;    performing a reforming process for removing organic impurities contained in said first layer by heating said first layer to a temperature lower than a crystallizing temperature of said material within an atmosphere containing active oxygen atoms;    depositing a second layer in an amorphous state by CVD on said first layer having being reformed;    placing said target substrate having said second layer deposited thereon on a work table arranged within an airtight process chamber;    performing a reforming process for removing organic impurities contained in said second layer by supplying a process gas containing oxygen atoms into said process chamber and by heating over a first period said second layer deposited on said target substrate placed on said work table to a first temperature lower than said crystallizing temperature; and    performing a crystallizing process for crystallizing said first and second layers after said reforming process of said second layer by heating said first and second layers deposited on said target substrate placed on said work table to a second temperature higher than said crystallizing temperature, followed by cooling said first and second layers to a temperature lower than said crystallizing temperature, said first period being longer than a second period during which said first and second layers have a temperature higher than said crystallizing temperature.