Methods for etching high aspect ratio features

Abstract

Methods for forming features for high aspect ratio application in etch process are provided in the present invention. In one embodiment, the method for etching a dielectric layer disposed on a substrate includes placing a substrate having a portion of a dielectric layer exposed through a patterned photoresist layer in an etch chamber, supplying a gas mixture containing argon (Ar) gas into the etch chamber, forming a plasma from the gas mixture using dual frequency RF power and etching the exposed dielectric layer using the plasma formed from the gas mixture.

1 . A method for etching a dielectric layer disposed on a substrate, comprising:
 placing a substrate having a portion of a dielectric layer exposed through a patterned photoresist layer in an etch chamber;   supplying a gas mixture containing an inert gas into the etch chamber;   forming a plasma from the gas mixture using dual frequency RF power; and   etching the exposed dielectric layer using the plasma formed from the gas mixture.   
   
   
       2 . The method of  claim 1 , wherein the step of supplying the gas mixture further comprises:
 supplying a carbon fluorine containing gas and an oxygen containing gas into the etch chamber.   
   
   
       3 . The method of  claim 2 , wherein the carbon fluorine containing gas includes at least one of CH 2 F 2 , CHF 3 , CH 3 F, C 2 F 6 , CF 4 , C 3 F 8 , C 4 F 6  and C 4 F 8.    
   
   
       4 . The method of  claim 2 , wherein the carbon fluorine containing gas is C 4 F 6 . 
   
   
       5 . The method of  claim 2 , wherein the oxygen containing gas includes at least one of nitric oxide (NO), carbon monoxide (CO), nitrous oxide (N 2 O), and oxygen gas (O 2 ). 
   
   
       6 . The method of  claim 2 , wherein the oxygen containing gas is oxygen gas (O 2 ). 
   
   
       7 . The method of  claim 2 , wherein the step of supplying further comprises:
 supplying the carbon fluorine containing gas at a flow rate between about 200 sccm and about 2000 sccm; and   supplying the oxygen containing gas at a flow rate between about 20 sccm and about 200 sccm.   
   
   
       8 . The method of  claim 1 , wherein the inert gas is Ar and is supplied at a low flow rate between about 5 sccm and about 250 sccm. 
   
   
       9 . The method of  claim 1 , wherein the inert gas is Ar and is supplied at a flow rate less than 200 sccm. 
   
   
       10 . The method of  claim 1 , wherein the step of forming the plasma from the gas mixture using dual frequency RF power further comprises:
 supplying a first RF power into the etching chamber; and   supplying a second RF power into the etching chamber.   
   
   
       11 . The method of  claim 10 , wherein the first RF power has a RF frequency about 13.56 MHz. 
   
   
       12 . The method of  claim 10 , wherein the second RF power has a RF frequency about 2 MHz. 
   
   
       13 . The method of  claim 10 , wherein the step of forming the plasma from the gas mixture using dual frequency RF power further comprises:
 supplying the first RF power of about 50 Watts to about 4000 Watts; and   applying the second RF power of about 50 Watts to about 4000 Watts.   
   
   
       14 . The method of  claim 1 , wherein the dielectric layer includes at least one of silicon dioxide, boron-doped oxide (BSG), organosilicate, phosphosilicate glass (PSG), borophosphosilicate glass (BPSG), fluorine doped silicon oxide (FSG), tetraethoxysilane (TEOS) and carbon doped silicon oxide (SiOC). 
   
   
       15 . The method of  claim 1 , wherein the dielectric layer is tetraethoxysilane (TEOS). 
   
   
       16 . The method of  claim 1 , wherein the step of etching further comprises:
 maintaining the process pressure at between about 10 mTorr and about 350 mTorr.   
   
   
       17 . The method of  claim 1 , wherein the formed features have an aspect ratio greater than 1:5. 
   
   
       18 . The method of  claim 1 , further comprising:
 forming a feature in the dielectric layer having substantially straight sidewall and substantially flat bottom.   
   
   
       19 . The method of  claim 1 , further comprising:
 forming a feature in the dielectric layer having substantially no profile deformation.   
   
   
       20 . A method for etching a dielectric layer disposed on a substrate, comprising:
 placing a substrate having a portion of a dielectric layer exposed through a patterned photoresist layer in an etch chamber;   supplying a gas mixture containing at least argon (Ar) gas at a flow rate between about 5 sccm and about 250 sccm into the etch chamber;   forming a plasma from the gas mixture using dual frequency RF power; and   etching the exposed dielectric layer using the plasma formed from the gas mixture.   
   
   
       21 . The method of  claim 20 , wherein the step of forming the plasma from the gas mixture using dual frequency RF power further comprises:
 supplying a first RF power at a RF frequency at between about 13.56 MHz; and   supplying a second RF power at a RF frequency at between about 2 MHz.   
   
   
       22 . The method of  claim 20 , wherein the step of supplying the gas mixture further comprises:
 supplying at least a carbon fluorine containing gas and an oxygen containing gas into the etch chamber.   
   
   
       23 . A method for etching a dielectric layer disposed on a substrate, comprising:
 placing a substrate having a portion of a dielectric layer exposed through a patterned photoresist layer in an etch chamber;   supplying a gas mixture containing at least a carbon fluorine containing gas, an oxygen containing gas and at least argon (Ar) gas into the etch chamber, wherein the Ar gas flow is maintained at between about 5 sccm and about 250 sccm;   forming a plasma from the gas mixture using dual frequency RF power; and   etching the exposed dielectric layer using the plasma formed from the gas mixture.   
   
   
       24 . The method of  claim 23 , wherein the step of forming the plasma from the gas mixture using dual frequency RF power further comprises:
 supplying a first RF power at a RF frequency at between about 13.56 MHz; and   supplying a second RF power at a RF frequency at between about 2 MHz.