Composition and Method Used for Chemical Mechanical Planarization of Metals

Abstract

Compositions for use in CMP processing and methods of CMP processing. The composition utilizes low levels of particulate material, in combination with at least one amino acid, at least one oxidizer, and water to remove a metal layer such as one containing copper to a stop layer with high selectivity.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present patent application is a continuation application of U.S. patent application Ser. No. 12 / 213,141 filed on Jun. 16, 2008; which is a divisional application of U.S. patent application Ser. No. 10 / 744,285 filed on Dec. 23, 2003; which claims the benefit of the filing date of Provisional U.S. Patent Application No. 60 / 437,826 filed on Jan. 3, 2003. The entire disclosure of Ser. No. 12 / 213,141 U.S. patent application is incorporated into the present patent application by reference.FIELD OF THE INVENTION[0002]The invention is directed to compositions for use in planarizing a metal surface applied over a dielectric layer, metal layer, or semi-conductor layer, primarily in connection with the manufacture of integrated circuits. The invention also is directed to methods used in effecting the planarization of the metal surface.[0003]Chemical-mechanical planarization (CMP) is used extensively as a processing step in various planar fabrica...

AI Technical Summary

Benefits of technology

The present invention is about a chemical mechanical planarization (CMP) composition that can remove metal from a wafer without causing polishing effects. The composition has the following technical effects: tunable metal removal rates, high particle stability, uniform metal surface, low susceptibility to dishing and erosion, low defectivity response, and low surface roughness. The composition can be produced in a reduced water content form while retaining high particle stability and can produce a highly planarized surface on the wafer over a range of operating pH values. The composition can also minimize the formation of micro-scratches onto the metal surface of the wafer and can be more easily concentrated.

Problems solved by technology

Generally, it is not desired for the dissolution process to occur on the surface of the wafer.

It is undesirable in an abrasive-containing liquid for the particles to settle out of the suspension.

Nonetheless, the use of an abrasive component in the CMP liquid can produce undesired results on the wafer surface.

The abrasive can create micro-scratches on any exposed surface of the wafer resulting in a non optically-flat surface.

For example, these micro-scratches can lead to a defect in later processing whereby a thin metal line is trapped within the dielectric, causing shorts between adjacent metal lines or vias.

Further, residual particles of the abrasive can cause potential opens or shorts depending on the electrical nature of the particle.

As a result, exposing the wafer surface to the mechanical action of the rotating pad in the presence of abrasive causes certain regions of the wafer surface to be more quickly removed than others, creating surface anomalies and a varying topography.

It is believed that etching of the metal surface of the wafer is one of the factors which contributes to undesired dishing.

Etching is the nonselective removal of metal from the surface of a layer, which tends to both roughen the resultant surface and create a nonplanar surface.

Where an array of copper metal lines is located on a wafer substrate, the mechanical action of the rotating pad in the presence of abrasive tends to cause formation of individual recesses of copper which in turn results in a high polishing rate of the adjacent dielectric.

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