Apparatus for achieving ultra-high selectivity while etching silicon nitride

Abstract

Apparatuses for processing substrates are provided herein. Apparatuses include a plasma etch chamber having a showerhead and pedestal for holding a substrate having silicon nitride, at least one outlet for coupling to a vacuum, a solid non-functional silicon source, and a plasma generator. A solid silicon source may be upstream of a substrate, such as at or near a showerhead of a process chamber, or in a remote plasma generator. Apparatuses also include a plasma etch chamber, at least one outlet, a solid non-functional silicon source, a plasma generator, and a controller for controlling operations including instructions for causing introduction of a fluorinating gas and causing ignition of a plasma to form fluorine-containing etching species in the plasma etch chamber.

What is claimed is: 
     
         1 . An apparatus for processing substrates, the apparatus comprising:
 (a) a plasma etch chamber comprising a showerhead and a pedestal for holding a substrate comprising silicon nitride;   (b) at least one outlet for coupling to a vacuum;   (c) a solid non-functional silicon source; and   (d) a plasma generator.   
     
     
         2 . The apparatus of  claim 1 , wherein the solid non-functional silicon source is disposed upstream of the substrate. 
     
     
         3 . The apparatus of  claim 1 , wherein the plasma generator is a remote plasma generator and the solid non-functional silicon source is disposed in the remote plasma generator. 
     
     
         4 . The apparatus of  claim 1 , wherein the solid non-functional silicon source is disposed between the substrate and the showerhead of plasma etch chamber. 
     
     
         5 . The apparatus of  claim 1 , wherein the solid non-functional silicon source is disposed at or near the showerhead of the plasma etch chamber. 
     
     
         6 . The apparatus of  claim 1 , wherein the solid non-functional silicon source comprises two or more silicon sources. 
     
     
         7 . The apparatus of  claim 1 , wherein the solid non-functional silicon source is attached to a wall of the plasma generator. 
     
     
         8 . The apparatus of  claim 1 , wherein the solid non-functional silicon source is a silicon-containing compound selected from the group consisting of quartz, silicon, silicon germanium, silicon carbide, and silicon oxide. 
     
     
         9 . The apparatus of  claim 1 , wherein the solid non-functional silicon source is a ring. 
     
     
         10 . The apparatus of  claim 1 , wherein the solid non-functional silicon source is a rod. 
     
     
         11 . An apparatus for processing substrates, the apparatus comprising:
 (a) a plasma etch chamber comprising a showerhead and a pedestal for holding a substrate comprising silicon nitride;   (b) at least one outlet for coupling to a vacuum;   (c) a solid non-functional silicon source;   (d) a plasma generator; and   (e) a controller for controlling operations in the apparatus, comprising machine-readable instructions for:   (a) causing introduction of a fluorinating gas to the plasma generator; and   (b) causing ignition of a plasma to form fluorine-containing etching species in the plasma etch chamber.   
     
     
         12 . The apparatus of  claim 11 , wherein the fluorinating gas is selected from the group consisting of F 2 , SF 6 , CF 4 , CHF 3 , CH 2 F 2 , NF 3 , and combinations thereof. 
     
     
         13 . The apparatus of  claim 11 , wherein the machine-readable instructions further comprise instructions for causing providing of additional silicon to the plasma from a fluidic silicon source. 
     
     
         14 . The apparatus of  claim 13 , wherein the fluidic silicon source is a non-fluorinating fluidic silicon source. 
     
     
         15 . The apparatus of  claim 14 , wherein the non-fluorinating fluidic silicon source is selected from the group consisting of silane, disilane, tetraethyl orthosilicate, and tetramethyl silane. 
     
     
         16 . The apparatus of  claim 14 , wherein the non-fluorinating fluidic silicon source is a silicon-containing gas and wherein the machine-readable instructions further comprise instructions for causing the silicon-containing gas to be provided at a flow rate of less than about 10% of total flow rate of gases flowed into the plasma etch chamber. 
     
     
         17 . The apparatus of  claim 13 , wherein the fluidic silicon source is a gaseous silicon source. 
     
     
         18 . The apparatus of  claim 13 , wherein the fluidic silicon source is a liquid silicon source. 
     
     
         19 . The apparatus of  claim 13 , wherein the machine-readable instructions further comprise instructions for introducing the fluidic silicon source at a flow rate of at least about 0.5% of a total flow of gases by volume introduced to the plasma. 
     
     
         20 . The apparatus of  claim 11 , wherein the machine-readable instructions further comprise causing introduction of one or more oxidant gases.