The present disclosure provides an integrated circuit with an interconnect structure and a method for forming the integrated circuit. In one embodiment, a method of the present disclosure includes receiving a workpiece that includes a first recess in a dielectric layer over the workpiece, depositing a contact fill in the first recess and over the dielectric layer to form a contact feature, planarizing a top surface of the workpiece to remove the contact fill over the dielectric layer, depositing an interlayer dielectric layer over the planarized top surface of the workpiece, forming a second recess in the interlayer dielectric layer to expose the contact fill in the dielectric layer, recessing the contact fill by soaking the workpiece in a room temperature ionic liquid, and depositing a conductive layer over the recessed contact fill. The material forming the contact fill is soluble in the room temperature ionic liquid.

An etching composition is provided. The etching composition includes phosphoric acid, phosphoric anhydride, a silane compound represented by Formula 1 below and water:

##STR00001## wherein R.sup.1 to R.sup.6 are independently hydrogen, halogen, a substituted or unsubstituted C.sub.1-C.sub.20 hydrocarbyl group, a C.sub.1-C.sub.20 alkoxy group, a carboxy group, a carbonyl group, a nitro group, a tri(C.sub.1-C.sub.20-alkyl)silyl group, a phosphoryl group, or a cyano group. L is a direct bond or C.sub.1 to C.sub.3 hydrocarbylene, and A is an n-valent radical, while n is an integer of 1 to 4.

An etchant includes about 8 wt % to about 12 wt % of nitric acid, about 3 wt % to about 8 wt % of alkylsulfonic acid, about 7 wt % to about 12 wt % of a sulfate, about 40 wt % to about 55 wt % of an organic acid, about 0.5 wt % to about 5 wt % of an organic acid salt, and a balance of water.

An etchant includes about 8 wt % to about 12 wt % of nitric acid, about 3 wt % to about 8 wt % of alkylsulfonic acid, about 7 wt % to about 12 wt % of a sulfate, about 40 wt % to about 55 wt % of an organic acid, about 0.5 wt % to about 5 wt % of an organic acid salt, and a balance of water.

An etchant includes about 8 wt % to about 12 wt % of nitric acid, about 3 wt % to about 8 wt % of alkylsulfonic acid, about 7 wt % to about 12 wt % of a sulfate, about 40 wt % to about 55 wt % of an organic acid, about 0.5 wt % to about 5 wt % of an organic acid salt, and a balance of water.

The present disclosure is directed to etching compositions that are useful, e.g., for selectively removing tungsten (W) and/or titanium nitride (TiN) from a semiconductor substrate as an intermediate step in a multistep semiconductor manufacturing process.

Provided is a copper etchant composition including: a first organic acid containing one or more amine groups, and one or more carboxylic acid groups; a second organic acid; an amine compound; hydrogen peroxide; and a phosphate compound, which has the increased number of processing sheets and etching uniformity, when etching copper.

Provided is a copper etchant composition including: a first organic acid containing one or more amine groups, and one or more carboxylic acid groups; a second organic acid; an amine compound; hydrogen peroxide; and a phosphate compound, which has the increased number of processing sheets and etching uniformity, when etching copper.

The present disclosure relates to an etching solution composition for a tungsten layer including N-methylmorpholine N-oxide and water, which is effective in selectively etching only a tungsten-based metal without etching a titanium nitride-based metal or a titanium aluminum carbide layer.

The present disclosure relates to an etching solution composition for a tungsten layer including N-methylmorpholine N-oxide and water, which is effective in selectively etching only a tungsten-based metal without etching a titanium nitride-based metal or a titanium aluminum carbide layer.