Process chambers are cleaned from tin oxide deposits by a method that includes a step of forming a volatile tin-containing compound by exposing the tin oxide to a mixture of hydrogen (H.sub.2) and a hydrocarbon in a plasma, followed by a step that removes a carbon-containing polymer that formed as a result of the hydrocarbon exposure. The carbon-containing polymer can be removed by exposing the carbon-containing polymer to an oxygen-containing reactant (e.g., to O.sub.2 in a plasma), or to H.sub.2 in an absence of a hydrocarbon. These steps are repeated as many times as necessary to clean the process chamber. The method can be used to clean ALD, CVD, and PVD process chambers and is particularly useful for cleaning at a relatively low temperature of less than about 120° C.

Methods and systems for forming a structure including multiple carbon layers and structures formed using the method or system are disclosed. Exemplary methods include forming a first carbon layer and a second carbon layer, wherein a density and/or other property of the first carbon layer differs from the corresponding property of the second carbon layer.

Exemplary etching methods may include modifying an exposed surface of a layer of metal oxide on a substrate housed in a processing region of a semiconductor processing chamber to produce a modified portion of metal oxide. The methods may include contacting the modified portion of metal oxide with a fluorine-containing precursor. The contacting may produce a metal oxy-fluoride material. The methods may include flowing an etchant precursor into the processing region. The methods may include contacting the metal oxy-fluoride material with the etchant precursor. The methods may include removing the metal oxy-fluoride material.

In an example, a method includes depositing a first sidewall spacer layer over a substrate having a layer stack including alternating layers of a nanosheet and a sacrificial layer, and a dummy gate formed over the layer stack, the first sidewall spacer layer formed over the dummy gate. The method includes depositing a metal-containing liner over the first sidewall spacer layer; forming a first sidewall spacer along the dummy gate by anisotropically etching the metal-containing liner and the first sidewall spacer layer; performing an anisotropic etch back process to form a plurality of vertical recesses in the layer stack; laterally etching the layer stack and form a plurality of lateral recesses between adjacent nanosheets; depositing a second sidewall spacer layer to fill the plurality of lateral recesses; and etching a portion of the second sidewall spacer layer to expose tips of the nanosheet layers.

A semiconductor structure includes a semiconductor substrate, a metal layer, an interlayer dielectric (ILD) layer. The metal layer is disposed over the semiconductor substrate. The ILD layer is over the semiconductor substrate and laterally surrounding the metal layer, in which the ILD layer has a first portion in contact with a first sidewall of the metal layer and a second portion in contact with a second sidewall of the metal layer opposite to the first sidewall of the metal layer, and a width of the first portion of the ILD layer decreases as a distance from the semiconductor substrate increases.

A method of forming features over a semiconductor substrate is provided. The method includes supplying a gas mixture over a surface of a substrate at a continuous flow rate. A first radio frequency (RF) signal is delivered to an electrode while the gas mixture is supplied at the continuous flow rate to deposit a polymer layer over the surface of the substrate. The surface of the substrate includes an oxide containing portion and a nitride containing portion. A second RF signal is delivered to the electrode while continuously supplying the gas mixture at the continuous flow rate to selectively etch the oxide containing portion relative to the nitride containing portion.

Aspects of this disclosure relate to selective removal of material of a layer, such as a carbon-containing layer. The layer can be over a patterned structure of two different materials. Treating the layer to cause the removal agent to be catalytically activated by a first area of the patterned structure to remove material of the organic material over the first area at a greater rate than over a second area of the patterned structure having a different composition from the first area.

A dry etching method according to an embodiment of the present disclosure includes reacting an etching target film formed on a surface of a workpiece with a β-diketone and nitrogen dioxide to etch the etching target film in a non-plasma state, the etching target film containing a metal having an M-O bond energy of 5 eV or higher or an oxide of the metal.

A structure is manufactured by forming a mask that has an opening pattern on a fine recessed and projected structure of a substrate having the fine recessed and projected structure with an average period of 1 μm or less on a surface thereof, etching the surface of the substrate from a side of the mask to form a recessed portion which has an opening greater than the average period of the fine recessed and projected structure according to the opening pattern of the mask, the recessed portion having a depth equal to or greater than double a difference in height between recesses and projections of the fine recessed and projected structure, and then removing the mask.

A semiconductor device comprises a semiconductor material extending through a stack of alternating levels of a conductive material and an insulative material, and a material comprising cerium oxide and at least another oxide adjacent to the semiconductor material. Related electronic systems and methods are also disclosed.