Cleaning Agent for Substrate and Cleaning Method

Abstract

The present invention provides a cleaning agent for a substrate and a cleaning method thereof, which can effectively remove fine particles (particles) present on a surface of substrate or impurities derived from various kinds of metals (metallic impurities), without causing roughness surface of a substrate, in particular, a semiconductor substrate, and without causing corrosion or oxidation of metal wirings, in particular, copper wirings, provided on a surface of substrate, and can further remove at the same time a carbon defect present on a surface of substrate, without removing a metal corrosion inhibitor—Cu film, in particular, a Cu-BTA film. The present invention provides a cleaning agent for a substrate comprising [I] an organic acid having at least one carboxyl group and / or [II] a complexing agent, and [III] an organic solvent selected from the group consisting of (1) monohydric alcohols, (2) alkoxyalcohols, (3) glycols, (4) glycol ethers, (5) ketones and (6) nitriles, and a cleaning method for a surface of substrate, which comprises the surface of substrate is treated with said cleaning agent.

Description

TECHNICAL FIELD [0001] The present invention relates to a cleaning agent for a surface of substrate, in particular, for a surface of semiconductor substrate provided with copper wiring thereon, and to a cleaning method thereof. BACKGROUND ART [0002] Recently, with the spread of multilayer wirings on a surface of semiconductor substrate, a so-called chemical mechanical polishing (CMP) technique, by which a semiconductor substrate is mechanically polished and planarized, has been used in producing devices. [0003] In particular, accompanied to the tendency to a highly integrated LSI in recent years, a wiring used has been changed from conventional aluminum to copper (Cu) which has a lower electric resistance, and thus the CMP technique (Cu-CMP) has become essential, when semiconductors having a multilayer structure, in which copper wirings are provided in many layers on the surface thereof, are produced. [0004] The CMP is a method for planarizing a surface of semiconductor substrate us...

AI Technical Summary

Benefits of technology

[0013] The present invention has been made under such circumstances as described above, and provides a cleaning agent for a substrate and a cleaning method thereof, which can effectively remove fine particles (particles) present on a surface of substrate or impurities (metallic impurities) derived from various kinds of metals, without causing roughness surface of a substrate, in particular, a semiconductor substrate, and without causing corrosion or oxidation of metal wirings, in particular, copper wirings, provided on a surface of substrate, and further can remove at the same time the carbon defect present on a surface of substrate, without removing a metal corrosion inhibitor—Cu film, in particular, a Cu-BTA film. MEANS TO SOLVE THE PROBLEMS

[0017] Namely, the present inventors have, after intensively studying a way to achieve the above-described object, found that not only particles and metallic impurities on a surface of substrate can be removed without causing roughness surface of a semiconductor substrate or corrosion or oxidation of metal wirings, in particular, cupper wirings provided on a semiconductor substrate, but also a carbon defect remaining on a substrate surface can also be easily removed at the same time without losing a metal corrosion inhibitor—Cu film, in particular, a Cu-BTA film, by cleaning the substrate surface using a cleaning agent for substrate comprising [I] an organic acid having at least one carboxyl group and / or [II] a complexing agent and [III] a specified organic solvent, in particular, a cleaning agent for substrate comprising [I] an organic acid having at least one carboxyl group, [II] a complexing agent and [III] a specified organic solvent, and further that specified solvents, among organic solvents, are superior in exhibiting such an effect, and a combined use of the specified organic solvents and a compound having at least one phosphonic acid group in a molecule (a phosphonic acid type complexing agent) as a complexing agent is particularly preferable, and accomplished the present invention.

[0028] The organic solvent according to the present invention can remove a carbon defect without removing a metal corrosion inhibiting film (for example, a metal corrosion inhibitor—Cu film such as a Cu-BTA film) which has been formed on a surface of semiconductor substrate, and also can remove a carbon defect without dissolving, corroding, oxidizing or decomposing apparatus components relating to device production such as semiconductor materials, wiring materials and plug materials.

Problems solved by technology

And the semiconductor surface after the CMP process is contaminated with a large amount of abrasive grain itself used, metals contained in the slurry, or metallic impurities derived from metallic wirings or metallic plug polished, and further various kinds of particles.

Contamination of the surface of semiconductor substrate with the metallic impurities or the particles affects electric characteristics of the semiconductor, and causes to lose reliability of devices.

Further, since device is destructed when metallic contamination is significant, it is necessary to introduce a post-CMP cleaning process to remove metallic impurities or particles from the surface of semiconductor substrate.

On the other hand, since metallic copper on a surface of semiconductor is highly active, and easily corroded by a slight oxidizing power, it tends to cause an increase of wiring resistance or wire breaking.

However, these metal corrosion inhibitors may remain on a surface of semiconductor as a so-called carbon defect.

There has been a problem that when a semiconductor having a carbon defect remaining on a surface thereof is subjected to heat treatment in the subsequent process, during working of a device or the like, the carbon defect is burnt to oxidize a wiring material resulting in deterioration of the device performance, or an apprehension that multilayer wiring executed without removing the carbon defect tends to put the flatness of upper layer part into disorder, and make a correct lamination difficult to cause a serious defect in working of the device.

However, a cleaning agent, which is conventionally used in various cleaning processes such as a post-CMP cleaning process, cannot sufficiently remove the carbon defect, or apt to remove a metal corrosion inhibiting film that is needed to prevent corrosion of metal surface as described above.

Thus, an effective means has not been found which can remove only the carbon defect while maintaining the metal corrosion inhibiting effect, without removing a metal corrosion inhibitor—Cu film, in particular, a Cu-BTA film as described above.

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