Methods and compositions for removing Group VIII metal-containing materials from surfaces

Abstract

A method and composition for removing Group VIII metal-containing materials from a surface (preferably, a platinum-containing, and more preferably, a platinum-rhodium-containing surface) involves the use of a mixture of phosphoric acid, sulfuric acid, nitric acid, and hydrochloric acid.

Description

FIELD OF THE INVENTION [0001] The present invention relates to methods for removing Group VIII metal-containing materials (preferably, platinum-containing, and more preferably, platinum-rhodium-containing materials) from surfaces, particularly in the fabrication of semiconductor devices. BACKGROUND OF THE INVENTION [0002] Films of metals and metal oxides, particularly the heavier elements of Group VIII, are becoming important for a variety of electronic and electrochemical applications. This is at least because many of the Group VIII metal films are generally unreactive, resistant to diffusion of oxygen and silicon, and are good conductors. Oxides of certain of these metals also possess these properties, although perhaps to a different extent. [0003] Thus, films of Group VIII metals and metal oxides, particularly the second and third row metals (e.g., Ru, Os, Rh, Ir, Pd, and Pt) have suitable properties for a variety of uses in integrated circuits. For example, they can be used in i...

AI Technical Summary

Benefits of technology

The present invention provides methods for removing materials from surfaces that contain Group VIII metals, particularly platinum, using an acidic composition containing phosphoric acid, sulfuric acid, nitric acid, and hydrochloric acid. The methods involve contacting the surface with a polishing pad and using the acidic composition as an etchant or planarizing solution. The use of the acidic composition is facilitated by the presence of abrasive particles in the composition. The methods can be used in the manufacturing of semiconductor devices, where the Group VIII metals are present in the form of platinum or platinum alloy. The technical effects of the invention include improved efficiency in the removal of materials from Group VIII metal-containing surfaces and reduced damage to the substrate surface.

Problems solved by technology

Many surfaces that result during the formation of Group VIII metal-containing films, particularly in the wafer fabrication of semiconductor devices, do not have uniform height, and therefore, the wafer thickness is also non-uniform.

Further, surfaces may have defects such as crystal lattice damage, scratches, roughness, or embedded particles of dirt or dust.

Unfortunately, mechanical polishing tends to cause smearing (i.e., undesirable relocation of target material, particularly ductile materials) and the formation of defects (e.g., scratches), both of which can be detected optically, rather than the clean removal of the platinum.

Also, many commercially available abrasive slurries do not effectively planarize platinum or other Group VIII metal-containing surfaces either because no material is removed (which results in no change in resistance of the wafer) or the resultant surface has defects therein.

Etchants used for platinum include aqua regia (a mixture of nitric acid and hydrochloric acid); however, this does not generally etch alloys of platinum, particularly platinum-rhodium.

Compositions that do etch alloys such as platinum-rhodium include compounds that are not compatible with other fabrication processes and / or are difficult to apply.

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