Dry-etch for selective tungsten removal

摘要

Methods of selectively etching tungsten relative to silicon-containing films (e.g. silicon oxide, silicon carbon nitride and (poly)silicon) as well as tungsten oxide are described. The methods include a remote plasma etch formed from a fluorine-containing precursor and/or hydrogen (H2). Plasma effluents from the remote plasma are flowed into a substrate processing region where the plasma effluents react with the tungsten. The plasma effluents react with exposed surfaces and selectively remove tungsten while very slowly removing other exposed materials. Sequential and simultaneous methods are included to remove thin tungsten oxide which may, for example, result from exposure to the atmosphere.

主权项

1. A method of etching a patterned substrate in a substrate processing region of a substrate processing chamber, wherein the patterned substrate has a exposed tungsten region and an exposed second material region, the method comprising:
flowing a fluorine-containing precursor into a remote plasma region fluidly coupled to the substrate processing region while forming a plasma in the plasma region to produce plasma effluents, wherein the fluorine-containing precursor comprises a combination of nitrogen trifluoride (NF3) and methyl fluoride (CH3F); flowing the plasma effluents through a showerhead disposed between the remote plasma region and the substrate processing region; and etching the exposed tungsten from the substrate.