KR20060076835A - Cleaning solution for organic matter removal in chemical mechanical polishing process and cleaning method using the same - Google Patents

Abstract

A cleaning compound for removing organic matter in a chemical mechanical polishing (CMP) process and a cleaning method using the same are provided. According to the present invention, there is provided a cleaning compound for chemical mechanical polishing and cleaning comprising a hydrophilic solvent added to pure water and pure water for cleaning the chemical mechanically polished wafer surface to remove organic residues on the wafer surface. do.

CMP, cleaning, organic residue, hydrophilic, chelating agent, ion sulfant

Description

Cleaning chemical and cleaning method for removing organic material in chemical mechanical polishing process

FIG. 1 is a view schematically illustrating a cleaning compound for removing organic matter and a cleaning method using the same in a chemical mechanical polishing process according to an embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to semiconductor manufacturing technology, and more particularly, to a cleaning compound for removing organic matter in a chemical mechanical polishing (CMP) process and a cleaning method using the same.

As semiconductor devices become more integrated and require high-speed operation, chemical mechanical polishing (CMP) is being introduced for the patterning of material layers that are difficult to selectively etch, such as global planarization or copper (Cu) wiring. After the CMP process is performed, a cleaning process is performed to remove particles or / and residues generated from the CMP process from the wafer surface.

Since the CMP process uses a slurry containing abrasives, a post-CMP cleaning process is necessarily accompanied. Several unit processes have been developed and are currently being applied to ensure efficient cleaning efficiency. For example, the cleaning process is a method using a polyvinyl alcohol (PVA) scrubber using mechanical force, a megasonic process, which is a cleaning method using ultrasonic waves, and a chemical force. It can be broadly divided into wet cleaning.

Currently, two or more processes are being applied in combination to complement each other. For example, post-CMP cleaning processes generally proceed with the supply of PVA scrubbers and additional cleaning chemicals. That is, a cleaning pad or a cleaning roll made of PVA or the like is introduced to scrub the polished wafer surface to remove residues and / or particles, and to provide a cleaning compound to the polished wafer surface. It is intended to promote and assist in this removal.

The cleaning compounds used here are mostly used to prevent particles of polishing slurry from adsorbing onto the wafer and to remove residues and / or particles from previous or CMP processes. It is configured to perform. Commonly used cleaning compounds allow the adsorption of ion ions and metal ions to the wafer, which alters the electrical charge of the abrasive or abrasive particles in the slurry, thereby preventing the adsorption from the wafer. The chelating agent for removal is the mainstream.

However, even with the help of such a cleaning compound, it may occur that the polished wafer surface is not sufficiently cleaned. For example, if organic residues are generated on the polished wafer surface on which the CMP process has been performed and / or organic matters involved in the pre-CMP process step, these organics have been removed from the wafer surface by conventional cleaning compounds or / and cleaning methods. Difficult to remove Accordingly, there is a need for development of cleaning compounds and cleaning methods that can more effectively clean the polished surfaces of wafers.

The technical problem to be achieved by the present invention is to propose a cleaning compound and a cleaning method using the same that can implement more effective cleaning in the chemical mechanical polishing process.

An embodiment of the present invention for achieving the above technical problem,

Pure water for cleaning the chemical mechanically polished wafer surface; And

A cleaning compound for cleaning after chemical mechanical polishing, including a hydrophilic solvent added to the pure water to remove organic residues on the wafer surface, is presented.

The cleaning compound may further include an ion surfactant added to the pure water to prevent adhesion of abrasive slurry particles to the wafer surface.

The ion sulfant may include citric acid, tartaric acid, maleic acid, malic acid, oxalic acid, succinic acid or lactic acid. Can be.

The cleaning compound may further comprise a chelating agent added to the pure water to prevent adhesion of metal ions to the wafer surface.

The chelating agent may include ethylenediaminetetraacetic acid (EDTA: EthyleneDiamineTetrAacetic acid), nitrilotriacetic acid (NTA), or nafio-Teflon-Phosphotungstic Acid (NTPA).

The cleaning compound may further include a corrosion inhibitor added to the pure water to prevent corrosion of the chemical mechanically polished surface.

The corrosion inhibitor may include benzotriazole acid (BTA).

The hydrophilic solvent may include ethanol, carboxylic acid, amino acid, benzyl alcohol, t-butanol or I-propanol. Can be.

The chemical mechanically polished wafer surface may comprise a surface of an oxide layer and a surface of a copper layer patterned by a damascene process.

Another embodiment of the present invention for achieving the above technical problem,

Chemical mechanical polishing the wafer surface;

A method of cleaning after a chemical mechanical polishing comprising cleaning the polished wafer surface with pure water and a cleaning compound comprising a hydrophilic solvent added to the pure water to remove organic residues on the wafer surface.

The cleaning may further comprise providing the cleaning compound to the wafer surface and scrubbing the wafer surface using a cleaning pad or cleaning roll.

The cleaning compound may further include an ion surfactant, a chelating agent or a corrosion inhibitor.

The chemical mechanically polished wafer surface includes a copper layer surface and an oxide layer surface polished by a copper damascene process using a via first method, and the cleaning removes organic residues from the surface. It may further comprise the step of removing.

According to the present invention, organic matter can be effectively removed in a chemical mechanical polishing process.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In an embodiment of the present invention, in order to effectively remove organic residues generated or remaining on the wafer surface after chemical mechanical polishing (CMP), a cleaning compound capable of effectively removing organic matters and a cleaning method using the same are provided. do. The cleaning compound fed to the PVA roll scrubbing process to remove organic residues comprises an ion surfactant, a chelating agent and a hydrophilic solvent. In this case, DI water may be further included in the cleaning compound. Such cleaning compounds can be used to effectively remove organic residues remaining on the wafer surface during cleaning.

In particular, residues of various components such as particles and residues generated in the previous process and particles and residues generated in the CMP process may be generated on the wafer surface after CMP. In order to effectively remove this, information on each residue defect is essential, and generally, residues after CMP can be classified into particles by slurry, metal particles by device process, and organic residues. Can be. Since each residual defect is different in its properties, the mechanism for removal also shows a difference.

In particular, the Cu damascene process consists of several sequential processes, resulting in a large number of residues after copper CMP. In particular, in a damascene process that does not use a stop layer, via holes are formed in a reactive ion etch (RIE) to etch trenches aligned with the via holes after the via holes are formed. Trench etching is performed with the polymer filled. Thus, relatively many organics are used in this process.

Therefore, if the organic matter adsorbed on the surface of the oxide layer is not completely removed in this CMP process, many organic residues remain on the wafer surface after the CMP of the copper layer filling the via holes and / or trenches. In order to effectively remove these organic residues, an additional process for effectively removing organics is required. The process of effectively removing the organics, that is, the process of using the cleaning compound proposed in the embodiment of the present invention may be introduced in a manner that is additionally added to the existing cleaning process.

FIG. 1 is a view schematically illustrating a cleaning compound for removing organic matter and a cleaning method using the same in a chemical mechanical polishing process according to an embodiment of the present invention.

1, the post-CMP cleaning method according to the embodiment of the present invention first performs a CMP process (100). The CMP process may be a copper CMP process for forming a copper layer wiring. As a previous step of the CMP process, an interlayer insulating layer covering the lower copper layer is formed, and the interlayer insulating layer is selectively etched to form a lower copper layer. After forming the exposed via hole, a process of forming a polymer layer filling the via hole and forming a trench aligned with the via hole may be performed. By such a preliminary step, a large amount of organic matter may remain on the surface of the interlayer insulating layer, and even after CMP and patterning the copper layer filling the trench by the residue, such residues may cause a large amount of organic residue. Can be generated.

As such, after the CMP, the CMP wafer surface may be cleaned by scrubbing using a cleaning pad such as a PVA pad. In this case, washing is performed using a cleaning compound including a hydrophilic solvent (200). The cleaning compound including the hydrophilic solvent according to the embodiment of the present invention can realize the effect of effectively removing the organic residue on the wafer surface by the addition of the hydrophilic solvent.

The cleaning compound according to the embodiment of the present invention is composed of water containing pure water. Based on water, the cleaning compound may comprise an ion sulfant, a chelating agent, a corrosion inhibitor or / and a hydrophilic solvent.

An ion surfactant, i.e., an ion surfacing agent, electrically charges the slurry particles to prevent adhesion of the particles to the wafer. For example, citric acid, tartaric acid, maleic acid, malic acid, oxalic acid, succinic acid, lactic acid, etc. It can be used as a factor.

Chelating agents are introduced to prevent the adhesion of metal ions to the wafer. For example, ethylenediaminetetraacetic acid (EDTA: EthyleneDiamineTetrAacetic acid), nitrilotriacetic acid (NTA), or Nafio-Teflon-Phosphotungstic Acid (NTPA) may be used.

Corrosion inhibitors are introduced to prevent corrosion of the surface of the polished copper layer. For example, benzotriazole acid (BTA) may be used.

Hydrophilic solvents remove organic matter from the wafer surface. For example, ethanol, carboxylic acid, amino acid, benzyl alcohol, t-butanol, I-propanol and the like can be used. . These hydrophilic solvents have hydrophilic properties and can be mixed with the other chemical components described above.

The cleaning compound according to this embodiment of the present invention can be used to effectively remove organic residue from the CMP wafer surface after CMP of a metal layer such as a copper layer.

According to the present invention described above, by effectively removing the organic residue remaining on the surface after copper layer chemical mechanical polishing (Cu CMP), it is possible to reduce the defect caused by the organic residue, Process stability and reproducibility can be secured.

Although the present invention has been described through specific embodiments, the present invention may be modified in various forms by those skilled in the art within the technical spirit of the present invention.

Claims (14)

Pure water for cleaning the chemical mechanically polished wafer surface; And And a hydrophilic solvent added to the pure water to remove organic residues on the wafer surface. The method of claim 1, And an ion surfactant added to the pure water to prevent adhesion of abrasive slurry particles to the wafer surface. The method of claim 2, The ion sulfant includes citric acid, tartaric acid, maleic acid, malic acid, oxalic acid, succinic acid and lactic acid. Cleaning compound for cleaning after chemical mechanical polishing comprising any one selected from the group consisting of. The method of claim 1, And a chelating agent added to the pure water to prevent adhesion of metal ions to the wafer surface. The method of claim 4, wherein The chelating agent is selected from the group consisting of ethylenediaminetetraacetic acid (EDTA: EthyleneDiamineTetrAacetic acid), nitrilotriacetic acid (NTA), and nafio-Teflon-Phosphotungstic Acid (NTPA). Cleaning compound for cleaning after chemical mechanical polishing, characterized in that it comprises any one of. The method of claim 1, A cleaning compound for cleaning after chemical mechanical polishing, further comprising a corrosion inhibitor added to the pure water to prevent corrosion of the chemical mechanically polished surface. The method of claim 6, The corrosion inhibitor is a cleaning compound for cleaning after chemical mechanical polishing, characterized in that it comprises benzotriazole acid (BTA: Benzo Triazole Acid). The method of claim 1, The hydrophilic solvent includes ethanol, carboxylic acid, amino acid, benzyl alcohol, t-butanol, and I-propanol. Cleaning compound for cleaning after chemical mechanical polishing, characterized in that it comprises any one selected from the group consisting of. The method of claim 1, And the chemical mechanically polished wafer surface comprises a surface of an oxide layer and a surface of a copper layer patterned by a damascene process. Chemical mechanical polishing the wafer surface; And And cleaning the polished wafer surface using a cleaning compound comprising pure water and a hydrophilic solvent added to the pure water to remove organic residues on the wafer surface. The method of claim 10, The cleaning further comprising providing the cleaning compound to the wafer surface and scrubbing the wafer surface using a cleaning roll. The method of claim 10, The cleaning compound after the chemical mechanical polishing, characterized in that it further comprises an ion surfactant, a chelating agent (corrosion inhibitor) or a corrosion inhibitor (corrosion inhibitor). The method of claim 10, The hydrophilic solvent includes ethanol, carboxylic acid, amino acid, benzyl alcohol, t-butanol and I-propanol. The chemical mechanical polishing after cleaning method comprising any one selected from the group consisting of. The method of claim 10, The chemical mechanically polished wafer surface includes a copper layer surface and an oxide layer surface polished by a copper damascene process using a via first method, and the cleaning includes removing organic residues from the surface. Method of cleaning after chemical mechanical polishing comprising a.

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