阅读说明：本技术 清洗液组合物 (Cleaning liquid composition ) 是由 高中亚铃治 于 2019-09-19 设计创作，主要内容包括：本发明的目的在于,提供短时间内有效地去除在具有Co接触插头或Co布线的半导体基板中的来源于浆料的有机残留物或磨粒的清洗液。本发明涉及包含一种或两种以上的还原剂及水的用于清洗具有Co接触插头和/或Co布线的基板的清洗液组合物。并且,本发明涉及包含一种或两种以上的还原剂及水,pH为3以上且小于12的用于清洗具有Co且不具有Cu的基板的清洗液组合物。(The purpose of the present invention is to provide a cleaning solution that effectively removes organic residues or abrasive grains derived from a slurry in a semiconductor substrate having a Co contact plug or a Co wiring in a short time. The present invention relates to a cleaning liquid composition for cleaning a substrate having a Co contact plug and/or a Co wiring, which contains one or more reducing agents and water. The present invention also relates to a cleaning liquid composition for cleaning a Co-containing and Cu-free substrate, which contains one or two or more reducing agents and water and has a pH of 3 or more and less than 12.)

1. A cleaning liquid composition for cleaning a substrate having a Co contact plug and/or a Co wiring,

comprises one or more than two reducing agents and water.

2. A cleaning liquid composition for cleaning a substrate having Co and no Cu, characterized by comprising one or more reducing agents and water, and having a pH of 3 or more and less than 12.

3. The cleaning solution composition as claimed in claim 2, wherein the substrate has a Co contact plug and/or a Co wiring.

4. The cleaning liquid composition according to any one of claims 1 to 3, wherein the reducing agent comprises one or more selected from the group consisting of five-membered ring or six-membered ring compounds in which two or more hydroxyl groups are directly bonded to a ring.

5. The cleaning liquid composition according to claim 4, wherein the reducing agent is one or more selected from the group consisting of ascorbic acid, pyrogallol, and methyl gallic acid.

6. The cleaning liquid composition according to any one of claims 1 to 5, characterized by further comprising one or more than two polysulfonic acid compounds as a surfactant.

7. A stock solution composition for a cleaning liquid composition according to any one of claims 1 to 6, which is used for obtaining the cleaning liquid composition by diluting it 10-fold to 1000-fold.

8. A method for manufacturing a semiconductor substrate is characterized in that,

comprising the step of contacting the cleaning liquid composition as claimed in any one of claims 1 to 6 with a substrate having a Co contact plug and/or a Co wiring.

9. The method for manufacturing a semiconductor substrate according to claim 8, wherein the step of contacting the substrate having the Co contact plug and/or the Co wiring is preceded by a step of chemically mechanically polishing the substrate having the Co contact plug and/or the Co wiring.

10. The method for manufacturing a semiconductor substrate according to claim 8 or 9, wherein the step of contacting the substrate having the Co contact plug and/or the Co wiring is a step of cleaning the substrate having the Co contact plug and/or the Co wiring.

Technical Field

The present invention relates to a cleaning liquid composition for cleaning a substrate having Co.

Background

In recent years, with the progress of miniaturization of devices and structuring of multilayer wiring, precise planarization processing of a substrate surface is required in each process, and as a new technique in a semiconductor substrate manufacturing process, the following Chemical Mechanical Polishing (CMP) technique has been introduced: the wafer is pressed against a polishing cloth called a polishing cloth wheel while supplying a slurry of a mixture of abrasive grains and chemicals, and an insulating film or a metal material is polished and planarized by rotating to combine a chemical action and a physical action.

In the past, tungsten (W) has been used as a contact plug for pulling electrodes such as a gate, a source, and a drain of a transistor onto an insulating film, but with miniaturization, cobalt (Co) has been used as a material having lower resistance than W in advanced devices.

Further, the wiring (Middle of Line, MOL) electrically connecting these contact plugs and the upper layer portion is also shifted from copper (Cu) to Co with miniaturization.

In the process of forming the device, chemical mechanical polishing is performed by using a silicon compound such as alumina or silica or a cerium compound such as cerium oxide as a slurry of abrasive grains, as in the past.

The surface of the substrate after the chemical mechanical polishing is contaminated with particles represented by alumina, silica or ceria particles contained in the slurry, constituent substances of the surface to be polished, or metal impurities derived from chemicals contained in the slurry. Since these contaminants may cause pattern defects or poor adhesion, poor electrical characteristics, etc., they need to be completely removed before proceeding to the next process. As a conventional chemical mechanical polishing post-cleaning for removing these contaminants, brushing is performed by combining the chemical action of a cleaning liquid and the physical action of a sponge brush made of polyvinyl alcohol or the like.

Heretofore, in a semiconductor manufacturing process, Co has been used as a barrier metal to prevent diffusion of metal in Cu wiring, and although cleaning liquids for Cu and Co have been proposed (patent documents 1 to 4), it seems to be difficult to use these cleaning liquids for a contact plug or MOL using Co.

This is because Co used as a barrier metal or a liner is very thin, hardly remains on Co with respect to foreign matter or abrasive grains called organic residue generated from slurry, and since the area of Co is larger than that of the liner in a contact plug or MOL and organic residue or abrasive grains easily remain, it is difficult to think that a cleaning liquid that can be used for a barrier metal or a liner using Co is suitable, and in fact, it has proved to be true. Therefore, although a cleaning liquid corresponding to a Co contact plug or a wiring using Co (hereinafter, referred to as Co wiring) is required, such a cleaning liquid has not been proposed yet.

Documents of the prior art

Patent document

Patent document 1: japanese patent application laid-open No. 2008-528762

Patent document 2: japanese Kokai publication No. 2008-543060

Patent document 3: japanese laid-open patent publication No. 2015-519723

Patent document 4: JP 2015-524165A

Disclosure of Invention

Technical problem

Accordingly, an object of the present invention is to provide a cleaning solution for efficiently removing organic residues or abrasive grains derived from a slurry in a semiconductor substrate having a Co contact plug or a Co wiring in a short time. In particular, a cleaning solution is provided that effectively removes organic residues.

Means for solving the problems

In earnest studies for solving the above problems, the present inventors have found that: as a result of further research, the present inventors have completed the present invention by acting a cleaning liquid composition containing one or more reducing agents and water on organic residues of polymers, which are bonded in a complex manner by Co ions generated by chemical mechanical polishing and a preservative contained in a slurry, to change the valence of the Co ions, thereby weakening the chemical bonds forming the polymers and efficiently removing Co-containing organic residues or abrasive grains derived from the slurry in a short time.

That is, the present invention relates to the following.

[1] A cleaning liquid composition for cleaning a substrate having a Co contact plug and/or a Co wiring, which comprises one or more reducing agents and water.

[2] A cleaning liquid composition for cleaning a Co-containing and Cu-free substrate, which contains one or more reducing agents and water and has a pH of 3 or more and less than 12.

[3] The cleaning liquid composition according to [2] above, wherein the substrate has a Co contact plug and/or a Co wiring.

[4] The reducing agent comprises one or more cleaning liquid compositions as defined in any one of the above [1] to [3] selected from the group consisting of five-membered ring or six-membered ring compounds in which two or more hydroxyl groups are directly bonded to the ring.

[5] The reducing agent is one or more kinds of the cleaning composition according to [4] above selected from the group consisting of ascorbic acid, pyrogallol, and methyl gallic acid.

[6] The cleaning liquid composition according to any one of the above [1] to [5] further comprising one or more polysulfonic acid compounds as a surfactant.

[7] The stock solution composition for a cleaning liquid composition according to any one of [1] to [6] for obtaining the cleaning liquid composition by diluting the stock solution composition by 10 to 1000 times.

[8] A method for producing a semiconductor substrate, comprising the step of bringing the cleaning liquid composition according to any one of the above [1] to [6] into contact with a substrate having a Co contact plug and/or a Co wiring.

[9] The method for manufacturing a semiconductor substrate according to [8] above, which comprises a step of Chemical Mechanical Polishing (CMP) the substrate having the Co contact plug and/or the Co wiring before the step of contacting the substrate having the Co contact plug and/or the Co wiring.

[10] The method for producing a semiconductor substrate according to [8] or [9] above, wherein the step of contacting the substrate having a Co contact plug and/or a Co wiring is a step of cleaning the substrate having a Co contact plug and/or a Co wiring.

ADVANTAGEOUS EFFECTS OF INVENTION

The cleaning liquid composition of the present invention is used for cleaning a metal material surface of a substrate subjected to an abrasive treatment, an etching treatment, a Chemical Mechanical Polishing (CMP) treatment, or the like in a process for manufacturing an electronic device such as a semiconductor device, and effectively removing metal impurities, microparticles, and organic residues or abrasive grains containing Co as a reaction product of Co and an organic preservative in a short time. Also, the cleaning solution composition of the present invention can be used to dissolve Co-containing organic residues in all applications as well as to clean substrates.

In particular, it is suitable to remove Co-containing organic residues or abrasive particles in substrates having Co contact plugs and/or Co wiring.

Drawings

Fig. 1 is a graph showing the relationship between the kind and pH of a reducing agent contained in a cleaning liquid composition and the cleaning performance.

Fig. 2 is a graph showing the relationship between the presence or absence of the reducing agent containing the cleaning liquid composition, the presence or absence of the surfactant and the type of other components, and the cleaning performance.

FIG. 3 is a graph showing the relationship between the presence or absence of the reducing agent and the type of other components contained in the cleaning liquid composition and X-ray photoelectron spectroscopy (XPS) spectra.

FIG. 4 shows the presence or absence of a reducing agent and a surfactant of a cleaning liquid composition, pH, and Co and SiO₂And zeta potential of each particle of SiN.

Detailed Description

Hereinafter, the present invention will be described in detail based on preferred embodiments thereof.

First, the cleaning liquid composition and the stock solution composition of the present invention will be explained.

The cleaning liquid composition of the present invention is a cleaning liquid composition for cleaning a substrate having a Co contact plug and/or a Co wiring, and contains one or more reducing agents and water.

The reducing agent used in the present invention is not particularly limited as long as it can change the valence of Co ion, but may include, for example, a five-membered ring or a six-membered ring compound in which two or more hydroxyl groups are directly bonded to the ring, and the like. These reducing agents may be used alone or in combination of two or more.

The five-or six-membered ring in which two or more hydroxyl groups are directly bonded to the ring may be a saturated or unsaturated five-or six-membered ring, or an aromatic five-or six-membered ring. In the present invention, it is preferable to use an aromatic five-membered ring or an aromatic six-membered ring in which two or more hydroxyl groups are directly bonded to the ring, such as γ lactone group and phenyl group, but not limited thereto. Further, as long as two or more hydroxyl groups are directly bonded to the ring, a substituent other than the hydroxyl group may be directly bonded to the ring.

The reducing agent used in the present invention is preferably ascorbic acid, pyrogallol, and methyl gallic acid, and particularly preferably pyrogallol and methyl gallic acid from the viewpoint of stability of the cleaning solution.

In the present invention, the pH of the cleaning liquid composition is preferably less than 12, more preferably 3 or more and less than 12. From the viewpoint of cleaning performance of Co-containing organic residues and abrasive grains, a higher cleaning performance can be obtained at a pH of 4 to 9, and a pH of 6 to 9 is particularly preferable.

In addition, the cleaning liquid composition of the present invention may contain a surfactant in order to improve the removal of fine particles. The kind of the surfactant is appropriately selected according to the microparticle or the substrate to be removed, and is preferably, but not limited to, a polysulfonic acid compound. As the polysulfonic acid compound, there may be mentioned, for example, naphthalenesulfonic acid-formaldehyde condensate, polystyrenesulfonic acid, ligninsulfonic acid and salts thereof, and the like.

The organic residue may include, but is not limited to, Co-containing organic residues, which are dimers or oligomers of Co-crosslinked organometallic complexes generated by reacting Co with organic preservatives such as Benzotriazole (BTA) and the like during chemical mechanical polishing and are poorly soluble. The organic residue of the substrate that is the subject of the cleaning liquid composition according to the invention may comprise a high concentration of Co. In order to dissolve Co-containing organic residues in the cleaning solution, there is a method of changing the pH of the cleaning solution to cut the coordinate bond between Co and the organic preservative to reduce the molecular weight of Co.

Among the Co-containing organic residues, dimers or oligomers as Co-crosslinked organometallic complexes generated by reacting Co with organic preservatives such as Benzotriazole (BTA) during chemical mechanical polishing may include, but are not limited to, such as Co-Benzotriazole (BTA) complexes.

The Co-benzotriazole complex refers to a complex of Co and Benzotriazole (BTA) formed by crosslinking or the like, and may include, but is not limited to, a complex of Co-benzotriazole (Co-BTA) and Cu-benzotriazole (Co-BTA) in which a compound derived from, for example, SiO is mixed₂And inorganic compounds of the slurry.

The substrate having the Co contact plug and/or the Co wiring in the present invention may be any substrate as long as it is obtained after Chemical Mechanical Polishing (CMP), and may include, but is not limited to, for example, a substrate immediately after chemical mechanical polishing and a substrate immediately after an insulating film of an upper layer is processed by dry etching after the formation of the Co contact plug and/or the Co wiring. Among them, the substrate immediately after the chemical mechanical polishing is preferable.

The Chemical Mechanical Polishing (CMP) in the present invention can be performed according to well-known chemical mechanical polishing methods, and can include, but is not limited to, methods such as using SiO₂Or Al₂O₃A method of polishing with isoabrasive grains, a method of polishing without abrasive grains using electrolytic water, and the like. Among them, SiO is preferably used₂Or Al₂O₃And (3) polishing the isoabrasive grains.

The stock solution composition of the present invention is a composition for obtaining the cleaning liquid composition of the present invention by dilution, and can be obtained by diluting the stock solution composition by 10 times or more, preferably 10 to 1000 times, and more preferably 50 to 200 times, and is determined as appropriate depending on the constituent components.

Since the cleaning liquid composition of the present invention is mainly composed of water, when a dilution mixing device is installed in a production line of an electronic device, since the diluted ich liquid (the above-mentioned ich liquid includes a diluted liquid composed only of ultrapure water) is supplied as a stock solution composition and used by diluting it into a water-containing liquid immediately before use, there are advantages in that it is possible to reduce transportation costs, reduce carbon dioxide gas during transportation, and reduce manufacturing costs for manufacturers of electronic devices.

The cleaning solution composition of the present invention can be used for substrates having Co contact plugs and/or Co wiring, for example, and is particularly suitable for substrates having Co contact plugs and/or Co wiring and no Cu. The present invention is also applicable to a substrate after Chemical Mechanical Polishing (CMP), in which various wiring, barrier metal materials (Co, Ti-based compound, Ta-based compound, Ru, etc.) and insulating film materials (SiO) are removed from the substrate surface after chemical mechanical polishing₂In addition to a low dielectric constant (low-ok), there may be microparticles or metal impurities contained in the slurry. The microparticles are mainly such as alumina, silica, and ceria, and the metal impurities may include Cu dissolved and re-attached in the slurry during polishing, Fe derived from an oxidizing agent in the slurry, and a Co organometallic complex in which a Co preservative contained in the slurry reacts with Co, and the like.

In the present invention, the barrier metal is Co, a Ti-based compound, a Ta-based compound, Ru, or the like that uses a layer (barrier metal layer) formed between the contact plug or wiring of the semiconductor substrate and the insulating film to prevent the metal in the contact plug or wiring from diffusing into the insulating film.

Also, the low dielectric constant material is a material having a low dielectric constant for an interlayer insulating film or the like, and may include, but is not limited to, materials such as porous silicon, silicon-containing organic polymers, Tetraethoxysilane (TEOS), and the like. Specifically, black diamond (manufactured by applied materials corporation), Aurora (manufactured by american metal association), and the like may be included.

Next, a method of manufacturing a semiconductor substrate according to the present invention will be explained.

The method for producing a semiconductor substrate according to the present invention is a method for producing a semiconductor substrate including a step of bringing the cleaning liquid composition of the present invention into contact with a substrate having a Co contact plug and/or a Co wiring.

Further, the method for manufacturing a semiconductor substrate according to the present invention includes a step of Chemical Mechanical Polishing (CMP) the substrate having the Co contact plug and/or the Co wiring before the step of bringing the cleaning liquid composition of the present invention into contact with the substrate having the Co contact plug and/or the Co wiring.

As the process of bringing them into contact, there may be included, but not limited to, a cleaning process such as after chemical mechanical polishing and a cleaning process after processing an insulating film on the upper layer of the Co contact plug by dry etching. As a method for bringing them into contact, there may be included, but not limited to, a single wafer cleaning method such as scrubbing with a brush, a single wafer cleaning method in which a cleaning liquid is sprayed by a spray or a nozzle, an intermittent spray cleaning method, an intermittent immersion cleaning method, and the like. Among them, a single-wafer cleaning method using a brush scrubbing in combination and a single-wafer cleaning method using a cleaning liquid sprayed or sprayed from a nozzle are preferable, and a single-wafer cleaning method using a brush scrubbing in combination is particularly preferable.

The atmosphere to be brought into contact with the metal oxide film may include, but is not limited to, an atmosphere such as air, a nitrogen atmosphere, a vacuum, and the like. Among them, air and nitrogen atmosphere are preferable.

The contact time is appropriately selected according to the purpose, and is 0.5 to 5 minutes in the case of a single wafer cleaning method in which scrubbing is performed by a brush in combination with a single wafer cleaning method in which a cleaning liquid is sprayed or sprayed from a nozzle, or 0.5 to 30 minutes in the case of an intermittent spray cleaning method or an intermittent immersion cleaning method, but is not limited thereto.

The temperature is appropriately selected depending on the purpose, and is not particularly limited, and is 20 to 50 ℃ in the case of a single wafer cleaning method in which scrubbing is performed by a brush or a single wafer cleaning method in which a cleaning liquid is sprayed or jetted from a nozzle, or 20 to 100 ℃ in the case of an intermittent spray cleaning method or an intermittent immersion cleaning method.

The above-mentioned contact conditions may be appropriately combined according to the purpose.

As the semiconductor substrate, there may be included, but not limited to, materials such as silicon, silicon carbide, silicon nitride, gallium arsenide, gallium nitride, gallium phosphide, indium phosphide, and the like. Among these, silicon carbide, gallium arsenide, and gallium nitride are preferable, and silicon carbide are particularly preferable.

Next, a method for dissolving Co-containing organic residue according to the present invention will be explained.

The method for dissolving the Co-containing organic residue of the present invention comprises a step of bringing a cleaning liquid composition, which contains one or more reducing agents and water and has a pH of 4 to 9, into contact with the Co-containing organic residue.

The cleaning liquid composition is not particularly limited as long as it is the above-mentioned, and the cleaning liquid composition of the present invention described in detail can be used.

The method of bringing the two into contact is not particularly limited as long as it is the method described above.

Examples

Next, the cleaning liquid composition of the present invention will be described in more detail by the following examples, but the present invention is not limited thereto.

Evaluation A: cleanability of cleaning solution composition (number of defects after cleaning Co wafer)

(preparation of chemical mechanical polishing solution)

A slurry (model: HS-CB915-B, manufactured by Hitachi chemical Co., Ltd.) using silica having an average particle size of 70nm was diluted 3 times with ultrapure water (DIW) and mixed with a hydrogen peroxide solution to obtain a chemical mechanical polishing slurry.

(wafer to be polished)

A Co substrate (PVD-Co2 k/Ti/Th-SiO) having the following composition was prepared₂Si, made by Advanced materials Technology co., ltd.).

(polishing of wafer)

After polishing of the above-mentioned subject wafer to be polished for 30 seconds by a polishing apparatus (model: ARW-681MSII, chemical mechanical polishing apparatus manufactured by Matt co., ltd.) using the above-mentioned chemical mechanical polishing slurry, the wafer was rinsed for 10 seconds with 100mL of ultrapure water (DIW) while being rotated. The wafers were cleaned for 60 seconds by rotating a brush made of polyvinyl alcohol (manufactured by Aion) while rotating the rinsed wafers using the cleaning solution compositions of table 1 and table 2 (except examples 11 and 12, cleaning solutions after chemical mechanical polishing using hydrochloric acid and tetramethylammonium hydroxide (TMAH) to adjust the pH to a predetermined value of pH. and examples 11 and 12 were cleaning solutions after chemical mechanical polishing of alkaline Cu for a Co barrier metal and acidic Cu for a Ta barrier metal, respectively, without including a reducing agent manufactured by kanto chemical). The cleaned wafer was rinsed with 300mL of ultrapure water (DIW) for 30 seconds while being rotated, and the wafer for measurement was obtained by drying at 25 ℃ for 30 seconds while being rotated again.

(measurement of the number of surface defects of a wafer)

The above-mentioned wafer surface for measurement was measured for the number of defects by a surface inspection apparatus (model: WM-10, manufactured by Topcon) to evaluate the cleanability of the cleaning liquid composition. The evaluation results are shown in fig. 1 and 2.

(results)

As shown in table 1, table 2, fig. 1 and fig. 2, it was confirmed that: at the same pH of 12, the number of defects on the wafer surface cleaned in the cleaning solution composition containing the reducing agent was smaller than the number of defects on the wafer surface cleaned in the cleaning solution composition containing no reducing agent (examples 10, 11 and 13). Namely, it was confirmed that: the cleaning liquid composition containing the reducing agent has higher cleaning performance than the cleaning liquid composition containing no reducing agent. Further, it was confirmed that, even in the cleaning liquid composition containing the reducing agent, the cleaning liquid compositions having pH4, 6, and 9 had higher cleaning performance than the cleaning liquid composition having pH 12. In general, the cleaning liquids used for cleaning Cu (examples 11 and 12) are not suitable for use as a cleaning liquid for Co and have more excellent cleaning performance than the cleaning liquid of the cleaning liquid composition of the present invention.

TABLE 1

TABLE 2

Evaluation B: removability of organic residue of cleaning liquid composition (removability of Co-benzotriazole)

(preparation of Co-benzotriazole substrate)

A Co substrate (PVD-Co2 k/Ti/Th-SiO) composed of₂Si, manufactured by Advanced materials Technology co., ltd.) cut to 1.0 × 1.0cm²After immersing these substrates in a 1% oxalic acid aqueous solution for 10 seconds, the substrates were rinsed with ultrapure water (DIW) for 1 minute, then immersed in a benzotriazole aqueous solution (10 mM in concentration, pH 8) for 2 minutes, rinsed again with ultrapure water (DIW) for 1 minute, and dried by blowing nitrogen gas, to obtain Co-benzotriazole substrates.

(preparation of substrate for evaluation)

A Co substrate (PVD-Co2 k/Ti/Th-SiO) composed of₂Si, manufactured by Advanced materials Technology co., ltd.) cut to 1.0 × 1.0cm²After immersing these substrates in a 1% oxalic acid aqueous solution for 10 seconds, the substrates were rinsed with ultrapure water (DIW) for one minute, then immersed in a benzotriazole aqueous solution (having a concentration of 10mM and a pH of not 8) for 2 minutes, then rinsed with ultrapure water (DIW) for 1 minute, immersed in each of the cleaning liquid compositions of tables 3 and 4 (the pH was adjusted to a predetermined pH using hydrochloric acid and tetramethylammonium hydroxide (TMAH)) for 1 minute, rinsed again with ultrapure water (DIW) for one minute, and dried by blowing nitrogen gas, to obtain evaluation substrates.

(evaluation of Co-benzotriazole removing ability)

The N1s spectrum of each of the above substrates was measured using X-ray photoelectron spectroscopy (X-ray photoelectron spectroscopy, model: JPS-9200, manufactured by Japan electronics). The spectral intensities of the evaluation substrates were compared with each other with the spectrum of the obtained Co-benzotriazole substrate as a reference, and the removal property of Co-benzotriazole was evaluated from the degree of decrease in intensity.

(results)

It can be confirmed that: the spectrum intensity of the X-ray photoelectron spectroscopy spectra of examples 18 to 20 at pH4 to pH9 shown in FIG. 3 is decreasing compared with the spectrum of Co-benzotriazole. It can be confirmed that: the spectra of X-ray photoelectron spectroscopy in examples 14 to 16, which did not contain a reducing agent, were reduced compared to the spectrum of Co-benzotriazole, but the reduction was less than in examples 18 to 20. From the above results, it was confirmed that: the reducing agent is effective for removing Co-benzotriazole (organic residue from the slurry).

TABLE 3

TABLE 4

Evaluation C: co, SiO in cleaning liquid composition₂And measurement of zeta potential of each particle of SiN

0.05g of cobalt (manufactured by SIGMA ALDRICH, SIGMA-ALDRICH) having an average particle size of 50nm was mixed with 20mL of ultrapure water (DIW), and after stirring for 10 minutes using an ultrasonic device to uniformly disperse it, 20 μ L of the above solution was collected and added to 50mL of a cleaning liquid composition having the components shown in table 5 (pH was adjusted to a predetermined pH using hydrochloric acid and tetramethylammonium hydroxide (TMAH)). These solutions were further stirred and homogenized, and the zeta potential of cobalt was measured using a zeta potential measuring device (model: ELS-Z, manufactured by tsukamur electronics).

The zeta potential (mV) was measured in the same manner as cobalt for each particle of silicon oxide and silicon nitride.

The results are shown in table 5 and fig. 4.

(results)

From table 5 and fig. 4, it was confirmed that: in the case of cobalt, the zeta potential in a cleaning liquid composition containing a reducing agent and/or a surfactant is lower than the zeta potential in a cleaning liquid composition not containing either a reducing agent or a surfactant. With respect to the silica, no large difference in zeta potential was observed depending on the composition of the cleaning liquid composition. And (3) confirming that: in the case of silicon nitride, the zeta potential in a cleaning liquid composition containing a reducing agent and/or a surfactant is lower than the zeta potential in a cleaning liquid composition containing neither a reducing agent nor a surfactant.

In particular, in the case of cobalt and silicon nitride, the zeta potential of the cleaning liquid composition containing the reducing agent exceeds 0 in the acidic region, whereas the zeta potential of the cleaning liquid composition containing the reducing agent and/or the surfactant exhibits a large negative zeta potential in a wide pH range of pH6 to 12. Therefore, the cleaning object including the cobalt wiring or the silicon nitride similarly exhibits a negative zeta potential. Since the silica abrasive grains contained in the cobalt abrasive slurry generally have a negative zeta potential, the present cleaning liquid composition using a reducing agent and/or a surfactant is expected to improve the effect of peeling off the silica abrasive grains by repulsion due to the negative zeta potential between the silica abrasive grains and the object to be cleaned, and to improve the cleaning performance while preventing reattachment to the object to be cleaned.

TABLE 5