Method and apparatus for etching photomasks

A method for etching a reticle comprising optically transparent molybdenum silicide and a patterned chromium layer disposed thereon, the method comprising:

• placing the reticle on a support member in a processing chamber having a coil;
• maintaining the reticle at a temperature of about 150° C. or less;
• introducing C2F6 into the processing chamber at a flow rate between about 25 sccm and about 50 sccm;
• introducing helium gas into the processing chamber at a flow rate between about 30 sccm and about 50 sccm;
• maintaining a chamber pressure between about 2 milliTorr and about 50 milliTorr;
• supplying a source RE power between about 50 watts and about 200 Watts to a coil;
• supplying a bias power between about 50 watts and about 200 Watts to the support member;
• and
• etching exposed portions of the optically transparent molybdenum silicide.

A method for etching a reticle comprising an optically transparent material comprising a molybdenum silicide material, a patterned metal layer deposited on the optically transparent material, and a patterned resist material deposited on the patterned metal layer, the method comprising:

• placing the reticle on a support member in a processing chamber;
• introducing a processing gas comprising:
• one or more hydrogen free fluorocarbon gases having the formula CxFy, where x is an integer from 1 to 5 and y is an integer from 4 to 8;
• and
• one or more inert gases;
• delivering power to the processing chamber by supplying a source RF power between about 50 watts and about 500 Watts or less to a coil and supplying a bias power to the support member between about 50 watts and about 500 Watts or less to generate a plasma;
• and
• etching exposed portions of the optically transparent material.