A plasma processing method according to the present disclosure is performed with a plasma processing apparatus, and includes: (a) preparing a substrate on a substrate support in the chamber, the substrate having an etching target film including a first silicon-containing film, and a first metal-containing film on the etching target film, the first metal-containing film including an opening pattern; and (b) etching the etching target film. (b) includes supplying a processing gas including one or more gases containing carbon, hydrogen, and fluorine into the chamber to form a plasma from the processing gas within the chamber and etch the first silicon-containing film to form the opening pattern in the first silicon-containing film, and a ratio of the number of hydrogen atoms to the number of fluorine atoms in the processing gas is 0.3 or more.

Provided are an etching composition including an oxidizing agent, an ammonium salt, an aqueous solvent, and an accelerator, a method of preparing a metal-containing film etching by using the same, and a method of manufacturing a semiconductor device by using the same.

A substrate processing method using a substrate processing apparatus including a process chamber having a reaction space for processing a substrate including an underlayer and a multilayer pattern provided on the underlayer and formed by alternately stacking at least a plurality of first insulating layers and a plurality of second insulating layers on one another, a substrate supporter, a gas ejector, and a plasma reactor, includes a pretreatment step for forming a passivation layer by supplying, onto the substrate through the gas ejector, a pretreatment gas, and an etching step for selectively and at least partially etching the plurality of second insulating layers in a lateral direction relative to the plurality of first insulating layers by supplying, onto the substrate through the gas ejector, an etchant.

An etching method for forming a high aspect ratio aperture by selectively etching one or more silicon-containing films in a substrate using a patterned mask layer deposited on top of the one or more silicon-containing films comprises: mounting the substrate in a processing chamber; introducing an etching gas containing a vapor of an oxygen-containing hydrofluorocarbon into the processing chamber; converting the etching gas to a plasma; and allowing an etching reaction to proceed between the plasma and the one or more silicon-containing films so that the one or more silicon-containing films are selectively etched versus the patterned mask layer to form the high aspect ratio aperture, wherein the oxygen-containing hydrofluorocarbon has a general formula C.sub.xH.sub.yF.sub.zO.sub.n, where 2x13, 1y15, 1z21, 1n3.