NITRIDE INHIBITORS FOR HIGH SELECTIVITY OF TiN-SiN CMP APPLICATIONS

Abstract

The invention provides a chemical-mechanical polishing composition comprising (a) abrasive particles, b) a removal rate inhibitor selected from (I) a surfactant comprising a polyoxyalkylene functional group and a sulfonate functional group, (II) a surfactant comprising a polyoxyalkylene functional group and a sulfate functional group, (III) a first surfactant comprising a polyoxyalkylene functional group and a second surfactant comprising a sulfonate functional group, and (IV) a first surfactant comprising a polyoxyalkylene functional group and a second surfactant comprising a sulfate functional group, and (c) an aqueous carrier. The invention also provides a method of chemically-mechanically polishing a substrate comprising TiN and SiN with the inventive chemical-mechanical polishing composition.

Description

BACKGROUND OF THE INVENTION[0001]In manufacturing of advanced semiconductor devices (both memory and logic) certain integration schemes require a selective removal of a metals (e.g., Cu, CuMn, Ta, TaN, Al, AlCo, Co, CoMo, Ru, RuTa, RuTiN, Mn, TiN (self-stop), W, Pt), dielectrics (e.g., silicon oxide, silicon nitride, silicon carbide, polysilicon), or polymers (e.g., photoreactive (PR), spin-on glass (SOG) type oxide) with cessation of removal upon reaching a barrier layer (commonly referred to as “stop on barrier”). Compositions and methods for chemical-mechanical polishing (CMP) of the surface of a substrate are well known in the art. Polishing compositions (also known as polishing slurries, CMP slurries, and CMP compositions) for CMP of surfaces of semiconductor substrates (e.g., for integrated circuit manufacture) typically contain an abrasive and various additive compounds. In the case of barrier layers formed from titanium nitride (TiN) and silicon nitride (SiN), the stop on ba...

AI Technical Summary

Benefits of technology

The invention is a method for polishing a substrate with a surface layer of titanium nitride (TiN) and silicon nitride (SiN). The method involves using a chemical-mechanical polishing composition containing abrasive particles and a removal rate inhibitor. When used with a polishing pad, the chemical-mechanical polishing composition selectively removes the TiN layer faster and with a higher removal rate selectivity than the SiN layer. This results in a polished substrate with a smooth surface.

Problems solved by technology

In the case of barrier layers formed from titanium nitride (TiN) and silicon nitride (SiN), the stop on barrier process can be difficult since typical CMP compositions are not particularly selective for removal of the overlying metal layer relative to the TiN or SiN layer.

One major difficulty in the stop on barrier technique is undesired removal of the planar portion of the barrier layer, which can lead to a lower gate height or other problems.

Often, CMP compositions are not selective enough to reliably and consistently stop material removal when the barrier layer is exposed.

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