High energy atomic layer etching

Abstract

Methods and apparatus for performing high energy atomic layer etching are provided herein. Methods include providing a substrate having a material to be etched, exposing a surface of the material to a modification gas to modify the surface and form a modified surface, and exposing the modified surface to an energetic particle to preferentially remove the modified surface relative to an underlying unmodified surface where the energetic particle has an ion energy sufficient to overcome an average surface binding energy of the underlying unmodified surface. The energy of the energetic particle used is very high; in some cases, the power applied to a bias used when exposing the modified surface to the energetic particle is at least 150 eV.

What is claimed is: 
     
         1 . An apparatus for processing a substrate, the apparatus comprising:
 a process chamber comprising a showerhead and a substrate support for holding the substrate having a material,   a plasma generator, and   a controller having at least one processor and a memory,   wherein the at least one processor and the memory are communicatively connected with one another,   the at least one processor is at least operatively connected with flow-control hardware, and   the memory stores machine-readable instructions for:   causing introduction of a modification gas to the process chamber;   causing introduction of a removal gas to the process chamber; and   causing an activation source to be pulsed during the introduction of the removal gas.   
     
     
         2 . The apparatus of  claim 1 , wherein the memory further stores machine-readable instructions for causing a pulse frequency of the activation source during the introduction of the removal gas to be between about 10 Hz and about 200 Hz. 
     
     
         3 . The apparatus of  claim 1 , wherein the memory further stores machine-readable instructions for causing a duty cycle of the activation source during the introduction of the removal gas to be less than 100% or between about 1% and about 20%. 
     
     
         4 . The apparatus of  claim 1 , wherein the activation source is a plasma generated in the process chamber using a plasma power and the memory further stores machine-readable instructions for causing the activation source to pulse between an OFF state where the plasma power is 0 W and an ON state where the plasma power is between about 50 W and about 900 W. 
     
     
         5 . The apparatus of  claim 1 , wherein the activation source is a plasma generated in the process chamber and the memory further stores machine-readable instructions for causing the activation source to pulse between a low plasma power and a high plasma power, the low plasma power being between about 10 W and about 100 W and the high plasma power being between about 900 W and about 1500 W. 
     
     
         6 . The apparatus of  claim 1 , wherein the memory further stores machine-readable instructions for causing a bias to be applied to the substrate support in pulses. 
     
     
         7 . The apparatus of  claim 6 , wherein the memory further stores machine-readable instructions for causing the bias to be pulsed between 0V and a bias voltage between about 20V and about 2000V. 
     
     
         8 . The apparatus of  claim 6 , wherein the memory further stores machine-readable instructions for causing the bias to be pulsed at a same pulsing frequency as the activation source. 
     
     
         9 . The apparatus of  claim 6 , wherein the memory further stores machine-readable instructions for causing the bias to be pulsed at a same pulsing duty cycle as the activation source. 
     
     
         10 . An apparatus for processing a substrate, the apparatus comprising:
 a process chamber comprising a showerhead and a substrate support for holding the substrate having a material,   a plasma generator, and   a controller having at least one processor and a memory,   wherein the at least one processor and the memory are communicatively connected with one another,   the at least one processor is at least operatively connected with flow-control hardware, and   the memory stores machine-readable instructions for:   causing introduction of a modification gas to the process chamber;   causing introduction of a removal gas to the process chamber; and   causing radio frequency plasma power to be generated in the process chamber in two or more temporally separated pulses during the introduction of the removal gas.   
     
     
         11 . The apparatus of  claim 10 , wherein the memory further stores machine-readable instructions for causing a pulse frequency of the radio frequency plasma power during the introduction of the removal gas to be between about 10 Hz and about 200 Hz. 
     
     
         12 . The apparatus of  claim 10 , wherein the memory further stores machine-readable instructions for causing a duty cycle of the radio frequency plasma power during the introduction of the removal gas to be less than 100% or between about 1% and about 20%. 
     
     
         13 . The apparatus of  claim 10 , wherein the memory further stores machine-readable instructions for causing the radio frequency plasma power to pulse between an OFF state where a plasma power is 0 W and an ON state where the plasma power is between about 50 W and about 900 W. 
     
     
         14 . The apparatus of  claim 10 , wherein the memory further stores machine-readable instructions for causing the radio frequency plasma power to pulse between a low plasma power and a high plasma power, the low plasma power being between about 10 W and about 100 W and the high plasma power being between about 900 W and about 1500 W. 
     
     
         15 . The apparatus of  claim 10 , wherein the memory further stores machine-readable instructions for causing a bias to be applied to the substrate support in pulses. 
     
     
         16 . The apparatus of  claim 15 , wherein the memory further stores machine-readable instructions for causing the bias to be pulsed between 0V and a bias voltage between about 20V and about 2000V. 
     
     
         17 . The apparatus of  claim 15 , wherein the memory further stores machine-readable instructions for causing the bias to be pulsed between a low bias voltage between about 50V and about 300V and a high bias voltage between about 500V and about 2000V. 
     
     
         18 . The apparatus of  claim 15 , wherein the memory further stores machine-readable instructions for causing the bias to be pulsed at a same pulsing frequency as the radio frequency plasma power. 
     
     
         19 . The apparatus of  claim 15 , wherein the memory further stores machine-readable instructions for causing the bias to be pulsed at a same pulsing duty cycle as the radio frequency plasma power. 
     
     
         20 . An apparatus for processing a substrate, the apparatus comprising:
 a process chamber comprising a showerhead and a substrate support for holding the substrate having a material,   a plasma generator, and   a controller having at least one processor and a memory,   wherein the at least one processor and the memory are communicatively connected with one another,   the at least one processor is at least operatively connected with flow-control hardware, and   the memory stores machine-readable instructions for:   causing introduction of a modification gas to the process chamber;   causing introduction of a removal gas to the process chamber; and   causing a bias power to be applied to the substrate support in two or more temporally separated pulses to the substrate during the introduction of the removal gas.   
     
     
         21 . The apparatus of  claim 20 , wherein the memory further stores machine-readable instructions for causing a pulse frequency of the bias power during the introduction of the removal gas to be between about 10 Hz and about 200 Hz. 
     
     
         22 . The apparatus of  claim 20 , wherein the memory further stores machine-readable instructions for causing a duty cycle of the bias power during the introduction of the removal gas to be less than 100% or between about 1% and about 20%. 
     
     
         23 . The apparatus of  claim 20 , wherein the memory further stores machine-readable instructions for causing the bias power to pulse between an OFF state where the bias power is 0V and an ON state where the bias power is between about 20V and about 2000V. 
     
     
         24 . The apparatus of  claim 20 , wherein the memory further stores machine-readable instructions for causing the bias power to pulse between a low bias power and a high bias power, the low bias power being between about 50V and about 300V and the high bias power being between about 500V and about 2000V. 
     
     
         25 . The apparatus of  claim 20 , wherein the memory further stores machine-readable instructions for causing a plasma to be ignited by applying a plasma power in pulses during the introduction of the removal gas. 
     
     
         26 . The apparatus of  claim 25 , wherein the memory further stores machine-readable instructions for causing the plasma power to be pulsed between 0 W and the plasma power between about 50 W and about 900 W. 
     
     
         27 . The apparatus of  claim 25 , wherein the memory further stores machine-readable instructions for causing the plasma power to be pulsed at a same pulsing frequency as the bias power. 
     
     
         28 . The apparatus of  claim 25 , wherein the memory further stores machine-readable instructions for causing the plasma power to be pulsed at a same pulsing duty cycle as the bias power.