A cleaning method for a by-product including a refractory material or a metal compound includes a reforming process and an etching process. In the reforming process, a surface of the by-product is reformed using nitrogen-containing gas and hydrogen-containing gas. In the etching process, the reformed surface is etched using halogen-containing gas and inert gas.

Methods for etching alkali metal compounds are disclosed. Some embodiments of the disclosure expose an alkali metal compound to an alcohol to form a volatile metal alkoxide. Some embodiments of the disclosure expose an alkali metal compound to a β-diketone to form a volatile alkali metal β-diketonate compound. Some embodiments of the disclosure are performed in-situ after a deposition process. Some embodiments of the disclosure provide methods which selectively etch alkali metal compounds.

Provided is a plasma etching method which enables etching with high accuracy while controlling and reducing surface roughness of a transition metal film. The etching is performed for the transition metal film, which is formed on a sample and contains a transition metal element, by a first step of isotropically generating a layer of transition metal oxide on a surface of the transition metal film while a temperature of the sample is maintained at 100° C. or lower, a second step of raising the temperature of the sample to a predetermined temperature of 150° C. or higher and 250° C. or lower while a complexation gas is supplied to the layer of transition metal oxide, a third step of subliming and removing a reactant generated by an reaction between the complexation gas and the transition metal oxide formed in the first step while the temperature of the sample is maintained at 150° C. or higher and 250° C. or lower, and a fourth step of cooling the sample.

A method for cleaning a substrate includes arranging the substrate in a processing chamber; controlling a pressure of the processing chamber to a predetermined pressure range; controlling a temperature of the processing chamber to a predetermined temperature range; and supplying a vapor mixture including a metal chelating vapor for a first period to remove metal contamination from surfaces of the substrate.

A method for cleaning a substrate includes arranging the substrate in a processing chamber; controlling a pressure of the processing chamber to a predetermined pressure range; controlling a temperature of the processing chamber to a predetermined temperature range; and supplying a vapor mixture including a metal chelating vapor for a first period to remove metal contamination from surfaces of the substrate.

In one exemplary embodiment, a substrate processing apparatus is provided. The substrate processing apparatus comprises: a chamber; a substrate support disposed in the chamber; a gas supply disposed in the chamber and connected to a supply source of reaction gas containing HF gas and C.sub.xH.sub.yF.sub.z gas (where x and z are integers equal to or greater than 1 and y is an integer equal to or greater than 0); and a plasma-generator configured to form a plasma from the reaction gas supplied to the chamber from the gas supply, wherein at least a portion of the chamber exposed to the plasma is made of a conductive silicon-containing material.

In one exemplary embodiment, a substrate processing apparatus is provided. The substrate processing apparatus comprises: a chamber; a substrate support disposed in the chamber; a gas supply disposed in the chamber and connected to a supply source of reaction gas containing HF gas and C.sub.xH.sub.yF.sub.z gas (where x and z are integers equal to or greater than 1 and y is an integer equal to or greater than 0); and a plasma-generator configured to form a plasma from the reaction gas supplied to the chamber from the gas supply, wherein at least a portion of the chamber exposed to the plasma is made of a conductive silicon-containing material.

Atomic layer etching (ALE) processes are disclosed. In some embodiments, the methods comprise at least one etch cycle in which a substrate comprising a metal, metal oxide, metal nitride or metal oxynitride layer is contacted with an etch reactant comprising an vapor-phase N-substituted derivative of amine compound. In some embodiments the etch reactant reacts with the substrate surface to form volatile species including metal atoms from the substrate surface. In some embodiments a metal or metal nitride surface is oxidized as part of the ALE cycle. In some embodiments a substrate surface is contacted with a halide as part of the ALE cycle. In some embodiments a substrate surface is contacted with a plasma reactant as part of the ALE cycle.

A metal removal method which includes: a reaction step of bringing a treatment gas containing a fluorine-containing interhalogen compound and a metal-containing material containing a metal element into contact with each other to generate metal fluoride which is a reaction product of the fluorine-containing interhalogen compound and the metal element; and a volatilization step of heating the metal fluoride under an inert gas atmosphere or in a vacuum environment for volatilization. The metal element is at least one kind selected from iron, cobalt, nickel, selenium, molybdenum, rhodium, palladium, tungsten, rhenium, iridium, and platinum. Also disclosed is a dry etching method using the metal removal method and a production method for a semiconductor element using the dry etching method.

A metal removal method which includes: a reaction step of bringing a treatment gas containing a fluorine-containing interhalogen compound and a metal-containing material containing a metal element into contact with each other to generate metal fluoride which is a reaction product of the fluorine-containing interhalogen compound and the metal element; and a volatilization step of heating the metal fluoride under an inert gas atmosphere or in a vacuum environment for volatilization. The metal element is at least one kind selected from iron, cobalt, nickel, selenium, molybdenum, rhodium, palladium, tungsten, rhenium, iridium, and platinum. Also disclosed is a dry etching method using the metal removal method and a production method for a semiconductor element using the dry etching method.