US2004000535A1PendingUtilityA1

Process for etching photomasks

33
Priority: Apr 19, 2002Filed: Apr 18, 2003Published: Jan 1, 2004
Est. expiryApr 19, 2022(expired)· nominal 20-yr term from priority
Inventors:Mark MuellerSerguei KomarovKi Ho Baik
G03F 1/80H01J 37/321C23F 4/00
33
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Claims

Abstract

Method and apparatus for etching a metal layer disposed on a substrate, such as a photolithographic reticle, are provided. In one aspect, a method is provided for processing a substrate including positioning a substrate having a metal photomask layer disposed on a silicon-based material in a processing chamber, introducing a processing gas at a flow rate of greater than about 350 sccm with the processing gas comprising an oxygen containing gas, a halogen containing gas, and optionally, an inert gas, into the processing chamber, generating a plasma of the processing gas in the processing chamber, generating a bias of about 50 watts or less, and etching exposed portions of the metal layer disposed on the substrate.

Claims

exact text as granted — not AI-modified
What is claimed is:  
     
         1 . A method for processing a photolithographic reticle, comprising: 
 positioning the reticle on a support member in a processing chamber, wherein the reticle comprises a metal photomask layer formed on a silicon-based substrate and a patterned resist material deposited on the metal photomask layer;    introducing a processing gas at a flow rate of at least 300 sccm, wherein the processing gas comprises an oxygen containing gas and a halogen containing gas;    delivering power to the processing chamber to generate a plasma of the processing gas;    supplying a bias power to the support member of greater than about 5 watts; and    removing exposed portions of the metal photomask layer.    
     
     
         2 . The method of  claim 1 , wherein the metal photomask layer comprises chromium, chromium oxynitride, or combinations thereof.  
     
     
         3 . The method of  claim 1 , wherein the silicon-based substrate comprises an optically transparent silicon-based material selected from the group of quartz, molybdenum silicide, molybdenum silicon oxynitride, and combinations thereof.  
     
     
         4 . The method of  claim 1 , wherein the oxygen containing gas has a flow rate of at least 100 sccm.  
     
     
         5 . The method of  claim 1 , wherein the oxygen containing gas has a flow rate between about 150 sccm and 400 sccm.  
     
     
         6 . The method of  claim 1 , wherein the oxygen containing gas is selected from the group of oxygen, carbon monoxide, carbon dioxide, and combinations thereof.  
     
     
         7 . The method of  claim 1 , wherein the halogen containing gas has a flow rate of at least 200 sccm.  
     
     
         8 . The method of  claim 1 , wherein the halogen containing gas has a flow rate between about 200 sccm and 600 sccm.  
     
     
         9 . The method of  claim 1 , wherein the processing gas has a flow rate between about 350 sccm and about 1000 sccm, wherein the oxygen containing gas has a flow rate between about 150 sccm and 400 sccm and the halogen containing gas has a flow rate between about 200 sccm and 600 sccm.  
     
     
         10 . The method of  claim 1 , wherein the halogen containing gas and the oxygen containing gas have a molar ratio between about 1:1.5 and about 4:1.  
     
     
         11 . The method of  claim 1 , wherein the halogen containing gas comprises a chlorine containing gas selected from the group of chlorine, carbon tetrachloride, hydrochloric acid, and combinations thereof.  
     
     
         12 . The method of  claim 1 , wherein the processing gas further comprises an inert gas selected from the group of helium, argon, xenon, neon, krypton, and combinations thereof.  
     
     
         13 . The method of  claim 1 , wherein the inert gas has a flow rate of about 500 sccm or less.  
     
     
         14 . The method of  claim 1 , wherein the bias power is supplied at between about 20 watts and about 40 watts.  
     
     
         15 . The method of  claim 1 , wherein the metal photomask layer and the resist material are removed at a removal rate ratio of metal photomask layer to resist material between about 1:1 and about 3:1.  
     
     
         16 . The method of  claim 1 , wherein processing the reticle comprises introducing the processing gas into a processing chamber, maintaining the processing chamber at a pressure between about 2 milliTorr and about 50 milliTorr, maintaining the reticle at a temperature between about 20° C. and about 150° C., and generating a plasma by supplying a source RF power between about 300 watts and about 1000 watts to a coil in the processing chamber.  
     
     
         17 . A method for processing a photolithographic reticle, comprising: 
 positioning the reticle on a support member in a processing chamber, wherein the reticle comprises a chromium-based photomask layer formed on an optically transparent silicon-based material and a patterned resist material deposited on the chromium-based photomask layer;    introducing a processing gas comprising chlorine gas and oxygen gas at a flow rate of at least 350 sccm, wherein the molar ratio between the chlorine gas and the oxygen gas is between about 1:1.5 and about 4:1;    maintaining a chamber pressure between about 2 milliTorr and about 50 milliTorr;    delivering power to the processing chamber of about 1000 watts or less to a coil disposed in the processing chamber to generate a plasma;    supplying a bias power to the support member of greater than about 5 watts; and    etching exposed portions of the chromium-based photomask layer; and    removing the chromium-based photomask layer at a removal rate ratio of chromium-based photomask layer to resist material of about 1:1 or greater.    
     
     
         18 . The method of  claim 17 , wherein the chromium-based photomask layer comprises chromium, chromium oxynitride, or combinations thereof, and the optically transparent silicon-based material comprises quartz, molybdenum silicide, molybdenum silicon oxynitride, or combinations thereof.  
     
     
         19 . The method of  claim 17 , further comprising introducing an inert gas selected from the group of helium, argon, xenon, neon, krypton, and combinations thereof.  
     
     
         20 . The method of  claim 17 , wherein the processing gas has a flow rate between about 350 sccm and about 1000 sccm, wherein the oxygen gas has a flow rate between about 150 sccm and 400 sccm and the chlorine gas has a flow rate between about 200 sccm and 600 sccm.  
     
     
         21 . The method of  claim 19 , wherein the inert gas has a flow rate of about 500 sccm or less.  
     
     
         22 . The method of  claim 17 , wherein the bias power is supplied at between about 20 watts and about 40 watts.  
     
     
         23 . The method of  claim 17 , wherein processing the reticle comprises introducing the processing gas into a processing chamber, maintaining the processing chamber at a pressure between about 2 milliTorr and about 50 milliTorr, maintaining the reticle at a temperature between about 20° C. and about 150° C., and generating a plasma by supplying a source RF power between about 300 watts and about 1000 watts to a coil to the processing chamber.  
     
     
         24 . The method of  claim 17 , wherein the delivering power to the processing chamber to generate a plasma of the processing gas further comprises a plasma strike.  
     
     
         25 . A method for processing a photolithographic reticle, comprising: 
 positioning the reticle on a support member in a processing chamber, wherein the reticle comprises a chromium-based photomask layer formed on an optically transparent silicon-based material and a patterned resist material deposited on the chromium-based photomask layer;    introducing a first processing gas comprising an inert gas, a halogen containing gas, and an oxygen containing gas, wherein the halogen containing gas and the oxygen containing gas have a flow rate of about 100 sccm or less;    delivering power to the processing chamber of about 1000 watts or less to a coil disposed in the processing chamber to generate a plasma;    introducing a second processing gas comprising a halogen containing gas and an oxygen containing gas, wherein the halogen containing gas and the oxygen containing gas have a flow rate of at least 350 sccm;    delivering power to the processing chamber of about 1000 watts or less to a coil disposed in the processing chamber to maintain a plasma;    supplying a bias power to the support member of greater than about 5 watts; and    etching exposed portions of the chromium-based photomask layer.    
     
     
         26 . The method of  claim 26 , wherein the second processing gas has an oxygen containing gas flow rate between about 150 sccm and 400 sccm, wherein the oxygen containing gas is selected from the group of oxygen, carbon monoxide, carbon dioxide, and combinations thereof.  
     
     
         27 . The method of  claim 26 , wherein the second processing gas halogen containing gas flow rate is between about 200 sccm and 600 sccm, wherein the halogen containing gas comprises a chlorine containing gas is selected from the group of chlorine, carbon tetrachloride, hydrochloric acid, and combinations thereof.  
     
     
         28 . The method of  claim 26 , wherein the second processing gas has a flow rate between about 350 sccm and about 1000 sccm, wherein the oxygen containing gas has a flow rate between about 150 sccm and 400 sccm and the halogen containing gas has a flow rate between about 200 sccm and 600 sccm.  
     
     
         29 . The method of  claim 26 , wherein the second processing gas has a molar ratio of the halogen containing gas to the oxygen containing between about 1:1.5 and about 4:1.  
     
     
         30 . The method of  claim 26 , wherein the second processing gas further comprises an inert gas selected from the group of helium, argon, xenon, neon, krypton, and combinations thereof.  
     
     
         31 . The method of  claim 26 , wherein the plasma is maintained by a process comprising maintaining the processing chamber at a pressure between about 2 milliTorr and about 50 milliTorr, maintaining the reticle at a temperature between about 50° C. and about 150° C., generating a plasma by supplying a source RF power between about 300 watts and about 1000 watts to a coil in the processing chamber, and supplying the bias power at between about 20 watts and about 40 watts.

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