JP2023024267A - Surface treatment method, method of manufacturing semiconductor substrate including the surface treatment method, surface treatment composition and system of manufacturing semiconductor substrate including the surface treatment composition - Google Patents

Abstract

To provide means enabling sufficient removal of residue which is present on a surface of a polished polishing target object including silicon oxide and includes inorganic oxide abrasive grains.SOLUTION: A surface treatment method is provided in which residues including inorganic oxide abrasive grains on a surface of a polished polishing target object including silicon oxide, is reduced using a surface treatment composition. The surface treatment composition includes: a zeta potential adjusting agent which has an sp value more than 9 and equal to or less than 11 and has a negatively charged functional group; and a dispersion media. The surface treatment method includes controlling a zeta potential of the silicon oxide to be negative and controlling a zeta potential of the inorganic oxide abrasive grains to be equal to or less than -30 mV by using the surface treatment composition.SELECTED DRAWING: None

Description

The present invention relates to a surface treatment method, a semiconductor substrate manufacturing method including the surface treatment method, a surface treatment composition, and a semiconductor substrate manufacturing system including the surface treatment composition.

2. Description of the Related Art In recent years, along with multi-layer wiring on the surface of a semiconductor substrate, a so-called chemical mechanical polishing (CMP) technique for polishing and flattening a semiconductor substrate has been used when manufacturing devices. CMP uses a polishing composition (slurry) containing, for example, abrasive grains such as silica, alumina, and ceria, additives such as anticorrosive agents and surfactants, to polish an object to be polished such as a semiconductor substrate (object to be polished). ) is a method of flattening the surface of The object to be polished (object to be polished) includes, for example, silicon, polysilicon, silicon oxide film (silicon oxide), silicon nitride, and wiring and plugs made of metal or the like.

A large amount of impurities (also called foreign matter or residue) remain on the surface of the semiconductor substrate after the CMP process. The foreign matter includes, for example, abrasive grains derived from the polishing composition used in CMP, organic substances such as anticorrosive agents and surfactants, silicon-containing materials produced by polishing the silicon-containing material to be polished, and polishing. It includes metals generated by polishing objects such as metal wiring and plugs, and organic substances such as pad scraps generated from various pads.

Contamination of the surface of the semiconductor substrate by these foreign substances may adversely affect the electrical characteristics of the semiconductor and reduce the reliability of the device. Therefore, it is desirable to introduce a surface treatment process after the CMP process to remove these foreign substances from the surface of the semiconductor substrate.

As a surface treatment composition used in such a cleaning step, for example, Patent Document 1 discloses a polycarboxylic acid or hydroxycarboxylic acid, a sulfonic acid-type anionic surfactant, and a carboxylic acid-type anionic surfactant. and water. The surface treatment composition is said to be able to remove foreign matter without corroding the substrate surface.

JP 2012-74678 A

However, the technique according to Patent Document 1 has a problem that foreign matter (residue) cannot be sufficiently removed when cleaning (surface treatment) a polished object to be polished.

Here, the inventors examined the relationship between the type of polished object to be polished and the type of foreign matter (residue). As a result, the inorganic oxide abrasive grains contained in the polishing composition used for polishing tend to adhere as residues to the surface of the polished object containing silicon oxide, which is particularly preferably used as a semiconductor substrate. It has been found that residues containing such inorganic oxide abrasive grains can cause deterioration in the performance of semiconductor devices.

The present invention has been made in view of the above problems, and provides means capable of sufficiently removing residues containing inorganic oxide abrasive grains present on the surface of a polished object containing silicon oxide. for the purpose.

In view of the above problems, the present inventors have made earnest studies. As a result, a surface treatment method for reducing residue containing inorganic oxide abrasive grains on the surface of a polished object containing silicon oxide using a surface treatment composition, wherein the surface treatment composition has an sp value of is greater than 9 and 11 or less and has a negatively charged functional group, and a dispersion medium, and the surface treatment composition controls the zeta potential of the silicon oxide to be negative, Further, the surface treatment method, which includes controlling the zeta potential of the inorganic oxide abrasive grains to −30 mV or less, improves the effect of removing residues containing inorganic oxide abrasive grains on the surface of the polished object to be polished. and completed the present invention.

One aspect of the present invention for solving the above-described problems is a surface treatment method that uses a surface treatment composition to reduce residue containing inorganic oxide abrasive grains on the surface of a polished object containing silicon oxide. The surface treatment composition comprises a zeta potential adjusting agent having an sp value of more than 9 and not more than 11 and having a negatively charged functional group, and a dispersion medium. The present invention relates to a surface treatment method comprising controlling the zeta potential of silicon oxide to be negative and controlling the zeta potential of the inorganic oxide abrasive grains to −30 mV or less.

Another aspect of the present invention for solving the above-mentioned problems is a surface treatment composition used for reducing residues containing inorganic oxide abrasive grains on the surface of a polished object containing silicon oxide. and a zeta potential adjusting agent having an sp value of more than 9 and not more than 11 and having a negatively charged functional group, and a dispersion medium, controlling the zeta potential of the silicon oxide to be negative, and The present invention relates to a surface treatment composition having a function of controlling the zeta potential of oxide abrasive grains to −30 mV or less.

According to the present invention, there is provided means capable of sufficiently removing residues containing inorganic oxide abrasive grains existing on the surface of a polished object to be polished.

Embodiments of the present invention will be described below, but the present invention is not limited only to the following embodiments. In this specification, unless otherwise specified, measurements of operations, physical properties, etc. are performed under the conditions of room temperature (20° C. or higher and 25° C. or lower)/relative humidity of 40% RH or higher and 50% RH or lower. Moreover, in this specification, the "inorganic oxide abrasive grains" contained in the polishing composition may be simply referred to as "abrasive grains". Furthermore, the object to be polished after being polished is also simply referred to as a "polished object to be polished".

As described above, the surface treatment method of the present invention is a surface treatment method that uses a surface treatment composition to reduce residues containing inorganic oxide abrasive grains on the surface of a polished object containing silicon oxide. , the surface treatment composition includes a zeta potential adjusting agent having an sp value of more than 9 and not more than 11 and having a negatively charged functional group, and a dispersion medium, and the surface treatment composition causes the oxidation Controlling the zeta potential of silicon to be negative and controlling the zeta potential of the inorganic oxide abrasive grains to −30 mV or less.

The method including controlling the zeta potential of silicon oxide to be negative and controlling the zeta potential of inorganic oxide abrasive grains to -30 mV or less by the surface treatment composition is not particularly limited, but sp value is 9 more than 11 and less than or equal to 11 and having a negatively charged functional group, and a dispersing medium. preferable.

According to the present invention, there is provided means capable of sufficiently removing residues containing inorganic oxide abrasive grains existing on the surface of a polished object to be polished.

Further, according to another embodiment of the present invention, the surface of a polished object containing silicon oxide is treated with a zeta potential adjustment agent having an sp value of more than 9 and not more than 11 and having negatively charged functional groups. Provided is a surface treatment method comprising treating with a surface treatment composition comprising an agent and a dispersion medium.

In the present specification, surface treatment refers to treatment for removing residues on the surface of a polished object, and represents cleaning treatment in a broad sense. A surface treatment method according to one aspect of the present invention is carried out by a method of directly contacting a surface treatment composition with a polished object to be polished. Although the surface treatment is not particularly limited, it is preferably performed by, for example, rinse polishing treatment or cleaning treatment.

A surface treatment method according to an embodiment of the present invention is preferably a method using a rinse polishing treatment. The reason for this is that the polishing process can be performed under the presence of pressure, so that the residue on the substrate surface can be physically desorbed and the zeta potential adjusting agent can be more strongly adsorbed to the substrate or the residue. Therefore, it is possible to more efficiently reduce the residue containing the inorganic oxide abrasive grains. Further, in the surface treatment method of the present invention, from the viewpoint of more efficiently reducing residues containing inorganic oxide abrasive grains, after the surface treatment of the polished object, it is washed with water (post-washing treatment described later). It is preferable to

The surface treatment (rinse polishing treatment and cleaning treatment) and post-cleaning treatment will be described later.

According to another embodiment of the present invention, there is provided a surface treatment composition used to reduce residue comprising inorganic oxide abrasive grains on the surface of a polished object comprising silicon oxide, the composition comprising: is greater than 9 and less than or equal to 11 and has a negatively charged functional group; Also provided is a surface treatment composition having a function of controlling the zeta potential of −30 mV or less.

Moreover, as described above, the surface treatment composition according to the present invention is preferably used in rinse polishing treatment or cleaning treatment. Therefore, the surface treatment composition according to the present invention can be a rinse polishing composition or a cleaning composition.

The surface treatment method of the present invention is characterized by the relationship between the surface treatment composition and the polished object to be surface treated using the surface treatment composition (that is, the object to be surface treated). have. Specifically, the surface treatment method of the present invention includes a surface treatment composition, components contained in a polished object, and components contained in a polishing composition obtained by polishing the polished object (more specifically, It was found that the relationship between the component of the polishing composition (abrasive grains) adhering to the surface of the polished object as residue affects the reduction of the residue on the surface of the polished object. This is because, as will be described later, the surface treatment method of the present invention reduces the electric charge (zeta potential) of the surface of the polished object to be polished and the components (abrasive grains) of the polishing composition present as residues on the surface of the polished object to be polished. This is because it is considered that the effect of the present invention is exhibited based on the electric charge (zeta potential) of .

In the following, first, the residue present on the surface of the polished object to be polished and the polished object to be surface-treated are described.

[Residue]
As used herein, the term "residue" refers to foreign matter adhering to the surface of the polished object. Examples of the residue include, but are not particularly limited to, particulate abrasive residue derived from abrasive grains contained in the polishing composition, organic residue described later, and other foreign matter.

In the present specification, the term "organic residue" refers to a component composed of organic substances such as organic low-molecular-weight compounds and high-molecular compounds, organic salts, and the like, among the foreign substances adhering to the polished surface of the object to be polished.

The organic residue adhering to the polished object is, for example, pad dust (e.g., polyurethane) generated from the pad used in the polishing treatment or surface treatment described below, or the polishing composition used in the polishing treatment or the surface treatment. and components derived from additives contained in the surface treatment composition. In the present invention, the number of polyurethane residues is calculated as the organic residue in the examples described later, so hereinafter, the organic residue means the organic residue containing polyurethane.

The total number of residues represents the total number of all residues regardless of the type. The total number of residues can be measured using a wafer defect inspection device (eg, optical inspection machine Surfscan (registered trademark) SP5, manufactured by KLA-Tencor Corporation). The details of the method for measuring the total number of residues will be described in Examples below.

Abrasive residue, organic residue, and other foreign matter differ greatly in color and shape. Judgment can be made by SEM observation. In addition, determination of whether the foreign matter is abrasive residue, organic residue, or other foreign matter, determination of the type of abrasive residue, and determination of the type of organic residue may be performed using an energy dispersive X-ray beam, if necessary. You may judge by the elemental analysis by an analyzer (EDX). The details of the method for measuring the number of abrasive grain residues and the number of polyurethane residues will be described later in Examples.

In the surface treatment method of the present invention, the surface treatment composition can control the zeta potential of residues on the surface of a polished object to be polished. Specifically, according to the surface treatment method of the present invention, the zeta potential of inorganic oxide abrasive grains (preferably cerium oxide abrasive grains) contained in the residue is controlled to −30 mV or less. Here, the term "inorganic oxide abrasive grains" as used herein means an inorganic oxide used as abrasive grains in the polishing composition. Therefore, when the residue contains inorganic oxide abrasive grains, the inorganic oxide abrasive grains become the abrasive grain residue.

From the viewpoint of the effects of the present invention, preferred examples of the inorganic oxide abrasive grains contained in the residue are not particularly limited, but cerium oxide abrasive grains, anion-modified Examples include silicon oxide abrasive grains. Therefore, according to the surface treatment method according to a preferred embodiment of the present invention, the inorganic oxide abrasive grains include at least one of cerium oxide abrasive grains and anion-modified silicon oxide abrasive grains, and the surface treatment composition The zeta potential of at least one of the cerium oxide abrasive grains and the anion-modified silicon oxide abrasive grains is controlled to −30 mV or less. According to the surface treatment method according to a more preferred embodiment of the present invention, the inorganic oxide abrasive grains contain cerium oxide abrasive grains, and the zeta potential of the cerium oxide abrasive grains is −30 mV or less due to the surface treatment composition. controlled by When the zeta potential of the inorganic oxide abrasive grains contained in the residue exceeds −30 mV, the residue aggregates to form coarse particles, which may not be removed by surface treatment.

Further, in a preferred embodiment of the present invention, the zeta potential of polyurethane contained in the residue is controlled to -10 mV or less. That is, according to the surface treatment method according to a preferred embodiment of the present invention, the residue further includes polyurethane, and the surface treatment composition further includes controlling the zeta potential of polyurethane to −30 mV or less. When the zeta potential of the polyurethane contained in the residue exceeds −30 mV, the residue aggregates to form coarse particles, which may not be removed by surface treatment.

The zeta potential of the inorganic oxide abrasive grains (preferably at least one of cerium oxide abrasive grains and anion-modified silicon oxide abrasive grains, more preferably cerium oxide abrasive grains) contained in the residue is preferably −65 mV or more, more preferably is -60 mV or higher, more preferably -55 mV or higher, particularly preferably -50 mV or higher. In addition, the zeta potential of the inorganic oxide abrasive grains (preferably at least one of cerium oxide abrasive grains and anion-modified silicon oxide abrasive grains, more preferably cerium oxide abrasive grains) contained in the residue is preferably −31 mV or less, It is more preferably -32 mV or less, still more preferably -34 mV or less, and particularly preferably -35 mV or less. In the surface treatment method, by controlling the zeta potential of the inorganic oxide abrasive grains to a value within the above range, the effects of the present invention are more exhibited. Moreover, the effect of the present invention is exhibited more by the surface treatment composition having the function of controlling the zeta potential of the inorganic oxide abrasive grains to a value within the above range.

The zeta potential of the polyurethane contained in the residue is preferably -75 mV or higher, more preferably -70 mV or higher, still more preferably -69 mV or higher, and particularly preferably -65 mV or higher. The zeta potential of the polyurethane contained in the residue is preferably −30 mV or less, more preferably −33 mV or less, still more preferably −35 mV or less, and particularly preferably −40 mV or less. In the surface treatment method, the effect of the present invention is exhibited more by controlling the zeta potential of the polyurethane to a value within the above range. Moreover, when the surface treatment composition has a function of controlling the zeta potential of polyurethane to a value within the above range, the effect of the present invention is more exhibited.

In this specification, the zeta potential of the inorganic oxide abrasive grains contained in the residue can be measured by Zetasizer Nano ZSP manufactured by Spectris Co., Ltd. (Malvern Division). The zeta potential of the polyurethane contained in the residue can be measured with a solid zeta potential measuring instrument SurPASS3 manufactured by Anton Paar Japan K.K. Details of the measuring method are described in Examples.

The zeta potential of the residue can be controlled by, for example, the type and amount of the zeta potential adjusting agent, the pH of the surface treatment composition, and the like. By increasing the negative charge of the zeta-potential control agent in the state of existence in the surface treatment composition, the zeta-potential of the inorganic oxide abrasive grains and polyurethane can be lowered. For example, an anionic surfactant can be selected as a zeta potential adjusting agent, or a group possessed by an anionic surfactant can be selected. Among them, by selecting a specific group as described later, the zeta potential of the inorganic oxide abrasive grains and polyurethane can be further lowered. In addition, the zeta potential of the inorganic oxide abrasive grains and the polyurethane can be further lowered by appropriately lowering the pH to a range that is not too low. By increasing the amount of the zeta potential adjusting agent in the surface treatment composition, the zeta potential lowering effect of the zeta potential adjusting agent can be further enhanced.

[Polished object to be polished]
In this specification, a polished object to be polished means an object to be polished after being polished in a polishing process. Although the polishing process is not particularly limited, it is preferably a CMP process.

A surface treatment composition according to one embodiment of the present invention is used to reduce residues remaining on the surface of a polished object containing silicon oxide. Polished objects containing silicon oxide include, for example, a TEOS-type silicon oxide surface produced using tetraethyl orthosilicate as a precursor (hereinafter also simply referred to as "TEOS"), an HDP film, a USG film, and a PSG film. film, BPSG film, RTO film, and the like.

The polished object to be polished is preferably a polished semiconductor substrate, more preferably a semiconductor substrate after CMP. The reason for this is that the residue can cause destruction of the semiconductor device, so when the polished object to be polished is a polished semiconductor substrate, the cleaning process of the semiconductor substrate should remove the residue as much as possible. is required.

The polished polishing object containing silicon oxide is not particularly limited, but may include a polished polishing object made of silicon oxide alone, a polished polishing object in which a material other than silicon oxide is exposed on the surface, and the like. mentioned. Here, the former includes, for example, a silicon oxide substrate which is a semiconductor substrate. As for the latter, examples of materials other than silicon oxide include silicon nitride, polysilicon, and tungsten. Specific examples of such a polished object to be polished include a polished semiconductor substrate having a structure in which a silicon oxide film is formed on silicon nitride, polysilicon or tungsten; A polished semiconductor substrate having a structure in which all the films and are exposed can be mentioned.

The surface treatment method of the present invention can control the zeta potential of silicon oxide contained in the polished object by the surface treatment composition. Specifically, according to the surface treatment method of the present invention, the zeta potential of silicon oxide is controlled to be negative.

The zeta potential of silicon oxide contained in the polished object is preferably −55 mV or more and −1 mV or less, more preferably −50 mV or more and −2 mV or less, further preferably −49 mV or more and −10 mV or less, Even more preferably -45 mV or more and -20 mV or less, and most preferably -42 mV or more and -30 mV or less. When the zeta potential of silicon oxide is within the above range, the initial effects of the present invention are more exhibited.

The zeta potential of silicon oxide can be controlled by, for example, the type and amount of the zeta potential adjusting agent, the pH of the surface treatment composition, and the like. By increasing the negative charge of the zeta potential adjusting agent in the state of existence in the surface treatment composition, the zeta potential of silicon oxide contained in the polished object can be lowered. For example, by selecting an anionic surfactant as the zeta potential adjusting agent, selecting a group possessed by the anionic surfactant, or selecting a specific group as described later, the polished object The zeta potential of silicon oxide contained in the substance can be further lowered. In addition, by appropriately lowering the pH to a range that is not too low, the zeta potential of silicon oxide contained in the polished object can be further lowered. By increasing the amount of the zeta potential adjusting agent in the surface treatment composition, the zeta potential lowering effect of the zeta potential adjusting agent can be further enhanced.

In the surface treatment method of the present invention, silicon nitride may be included as a material other than silicon oxide. When silicon nitride is contained as the inorganic oxide abrasive grains contained in the residue, for example, the zeta potential of silicon nitride can be controlled to be negative at a pH of less than 4. In this case, the zeta potential of silicon nitride contained in the polished object is preferably -65 mV or more and -1 mV or less, more preferably -62 mV or more and -2 mV or less, and still more preferably -60 mV or more and -10 mV or less. , still more preferably −58 mV or more and −15 mV or less, even more preferably −55 mV or more and −30 mV or less, and most preferably −52 mV or more and −35 mV or less.

Next, the surface treatment composition used in the surface treatment method of the present invention will be described.

[Surface treatment composition]
One embodiment of the present invention includes a zeta potential adjusting agent having an sp value of more than 9 and less than or equal to 11 and having a negatively charged functional group, and a dispersion medium to treat the surface of a polished object. It is a surface treatment composition used for Here, some components of the polishing composition tend to adhere to the surface of the polished object and remain on the surface of the polished object after polishing. In particular, inorganic oxide abrasive grains contained in the polishing composition tend to remain on the surface of the polished object. In this case, the inorganic oxide abrasive grains remaining on the surface of the polished object may cause foreign matter. The surface treatment composition according to the present invention can remove the polishing composition-derived residue (that is, inorganic oxide abrasive grains) remaining on the surface of such a polished object to be polished.

The surface treatment composition according to the present invention controls the zeta potential of the silicon oxide contained in the polished object to be negative, and the zeta potential of the inorganic oxide abrasive grains present as residues on the surface of the polished object. can be controlled to −30 mV or less. That is, the zeta potential of the silicon oxide and inorganic oxide abrasive grains on the surface of the polished object is controlled within the above range by contacting the polished object with the surface treatment composition of the present invention. Accordingly, the surface treatment composition according to the present invention can be used as a residue reducing agent for efficiently removing residues (inorganic oxide abrasive grains) in the surface treatment step.

Therefore, according to the present invention, there is provided a surface treatment composition used for reducing residue containing inorganic oxide abrasive grains on the surface of a polished object containing silicon oxide, wherein the sp value exceeds 9 is 11 or less and has a negatively charged functional group; A surface treatment composition is also provided that has the function of controlling to 30 mV or less.

In the surface treatment composition, the inorganic oxide abrasive grains contain cerium oxide abrasive grains, and the surface treatment composition has a function of controlling the zeta potential of the cerium oxide abrasive grains to −30 mV or less.

The surface treatment composition according to the present invention can also efficiently remove pad dust (polyurethane) generated from pads used in polishing or surface treatment. That is, these pad shavings also exist as residues on the surface of the polished object, but when the pad shavings are polyurethane, the surface treatment composition according to the present invention is used to remove polyurethane on the surface of the polished object. Efficient removal can be achieved by controlling the zeta potential. Therefore, in the surface treatment composition according to the present invention, the residue further contains polyurethane, and the surface treatment composition further has a function of controlling the zeta potential of the polyurethane to −30 mV or less.

The present inventors presume the mechanism by which the present invention solves the above problems as follows.

Since the zeta potential adjusting agent contained in the surface treatment composition has an sp value of more than 9 and not more than 11 and has a negatively charged functional group, the residue present on the surface of the polished object (inorganic oxide abrasive granules, polyurethane) to form a hydrophilic layer. The zeta potential adjusting agent also adheres to the surface of the polished object in the surface treatment composition to form a hydrophilic layer. Since the residue on which the hydrophilic layer is formed has an affinity for the hydrophilic surface of the polished object, it moves from the surface of the polished object (for example, moves toward the polishing pad) during the surface treatment step. maintains the state of adhesion to the polished object. Thereafter, by washing with water (post-washing treatment described later), the hydrophilic layer on the surface of the polished object is easily removed, and the residue on the surface of the polished object is also removed.

Therefore, the surface treatment composition according to the present invention is a polished surface due to chemical interaction between each component contained in the surface treatment composition, the surface of the polished object to be polished, and the residue on the surface of the polished object to be polished. It has the function of removing residues on the surface of the object to be polished, or the function of facilitating the removal.

It should be noted that the above mechanism is based on speculation, and its correctness or wrongness does not affect the technical scope of the present invention.

Each component contained in the surface treatment composition will be described below.

[Zeta potential adjusting agent]
A surface treatment composition according to one aspect of the present invention includes a zeta potential adjuster having an sp value of more than 9 and not more than 11 and having a negatively charged functional group. Here, the sp value is a solubility parameter, and the sp value of the zeta potential adjusting agent in this specification is determined by the Fedors method (Reference: RF Fedors, Polym. Eng. Sci., 14 [2] 147 ( 1974)).

The sp value of the zeta potential adjuster is more than 9 and 11 or less, preferably more than 9 and 10.9 or less, more preferably 9.5 or more and 10.8 or less. When the sp value exceeds 9 and is 11 or less, the affinity between the zeta potential control agent and the residue on the surface of the polished object increases, and the zeta potential control agent easily adheres to the residue. When the sp value of the zeta potential adjuster is 9 or less, it is significantly different from the sp value of water (23). It becomes easy to become a residue of When the sp value of the zeta potential control agent exceeds 11, based on approaching the sp value of water (23), the zeta potential control agent is more likely to It becomes more stable when it is more compatible with a dispersion medium (for example, water), and the effect of the present invention is not exhibited.

A zeta potential modifier has a negatively charged functional group. Such functional groups include, for example, at least one functional group selected from the group consisting of a sulfonic acid (salt) group, a sulfuric acid (salt) group, a phosphonic acid (salt) group, and a phosphoric acid (salt) group. mentioned. When the negatively charged functional groups are these groups, the effect of removing residues containing inorganic oxide abrasive grains present on the surface of the polished object containing silicon oxide is further improved. It is speculated that the reason for this is that by charging the surface of the polished object and the surface of the residue with the same negative charge, charge repulsion becomes effective and the residue can be detached and prevented from reattaching. be.

The zeta potential adjuster is preferably an anionic surfactant, more preferably an anionic surfactant having a weight average molecular weight of less than 1,000. The anionic surfactant easily forms a hydrophilic layer on the residue, and the formed hydrophilic layer can be easily removed by washing with water (post-washing treatment described later), and the surface treatment composition contributes to the removal of residues by Therefore, the surface treatment composition containing an anionic surfactant can sufficiently remove residues remaining on the surface of the polished object during the surface treatment of the polished object.

The weight average molecular weight of the anionic surfactant is preferably less than 1,000, more preferably 200 or more and less than 1,000, still more preferably 500 or more and 980 or less, and 800 or more and 959 or less. It is more preferable to have By setting the weight-average molecular weight of the anionic surfactant within the above range, the affinity for the residue can be improved, and the intended effects of the present invention can be further exhibited. The weight-average molecular weight of the anionic surfactant can be calculated from the molecular formula or measured as a value converted to polyethylene glycol using gel permeation chromatography (GPC).

Such an anionic surfactant has at least one functional group selected from the group consisting of a sulfonic acid (salt) group, a sulfuric acid (salt) group, a phosphonic acid (salt) group and a phosphoric acid (salt) group. compounds containing Among these, the functional group is preferably a sulfuric acid (salt) group, a phosphonic acid (salt) group, or a phosphoric acid (salt) group, and more preferably a sulfuric acid (salt) group or a phosphoric acid (salt) group.

The term "acid (salt)" as used herein means that the group or compound of interest may be in the form of an acid or a salt. Here, the sulfonic acid group is a sulfo group, the sulfate group is a group represented by —OSO ₃ H, the phosphonic acid group is a phospho group, and the phosphate group is —OPO represents a group represented by ₃ H ₂ ; The phosphonate group and phosphate group may be acidic bases in which one H remains. These groups may be in the form of a salt, and the salt is not particularly limited. Examples include alkali metal salts such as lithium salts, sodium salts, and potassium salts; Amine salts, ammonium salts and the like are included. Among these, alkali metal salts are preferred, and sodium salts are more preferred. The salt may be used alone or in combination of two or more.

The types of anionic surfactants used in the present invention will be described. The anionic surfactant described below may be a low-molecular-weight surfactant or a high-molecular-weight surfactant. type surfactants. As used herein, the term "low-molecular-weight surfactant" refers to a compound having a molecular weight of less than 1,000. The molecular weight of the compound can be determined using known mass spectrometry means such as TOF-MS and LC-MS. On the other hand, the term "polymeric surfactant" used herein refers to a compound having a molecular weight (weight average molecular weight) of 1,000 or more. Weight average molecular weight can be measured by gel permeation chromatography (GPC).

(Compound having a sulfonic acid (salt) group)
The compound having a sulfonic acid (salt) group as the anionic surfactant according to the present invention is not particularly limited as long as it is a surfactant having a sulfonic acid (salt) group.

Examples of compounds having a sulfonic acid (salt) group include alkylbenzenesulfonic acid (eg n-dodecylbenzenesulfonic acid), alkylsulfonic acid (eg laurylsulfonic acid), alkyldiphenyletherdisulfonic acid (eg lauryldiphenyletherdisulfonic acid), alkylnaphthalene Sulfonic acids or salts thereof, such as sulfonic acids (eg, lauryl naphthalene sulfonic acid). Examples of salts of these sulfonic acids include alkali metal salts such as sodium salts, Group 2 element salts such as calcium salts, amine salts, and ammonium salts. In particular, when the polished object to be polished is a semiconductor substrate after a CMP process, a sodium salt, an amine salt or an ammonium salt is preferable from the viewpoint of removing metal from the substrate surface as much as possible. For example, as the anionic surfactant having a sulfonic acid (salt) group, ammonium lauryl sulfonate and sodium lauryl diphenyl ether disulfonate are preferred.

Examples of the commercially available products include sulfonic acid group-containing modified polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Gohsenex L series), sulfonic acid group-containing copolymer (manufactured by Toagosei Co., Ltd., Aron (registered trademark) A series ), sulfonic acid group-containing copolymers (manufactured by Akzo Nobel, VERSA (registered trademark, the same applies hereinafter) series, NARLEX (registered trademark, the same applies hereinafter) series; manufactured by Tosoh Finechem Co., Ltd., ST series, MA series), polystyrene Sulfonic acid (salt) (manufactured by Tosoh Finechem Co., Ltd., Polynas (registered trademark, hereinafter the same) series), alkyldiphenyl ether disulfonate (manufactured by Takemoto Oil & Fat Co., Ltd., Pionin (registered trademark, hereinafter the same) A-43-D, A-43-S; Takesurf A-43-NQ) and the like can be used.

(Compound having a sulfate (salt) group)
The compound having a sulfate (salt) group as the anionic surfactant according to the present invention is not particularly limited as long as it is a surfactant containing a sulfate (salt) group.

Examples of compounds having a sulfuric acid (salt) group include alkyl sulfate salts (e.g. ammonium lauryl sulfate), polyoxyalkylene alkyl ether sulfate salts, polyoxyalkylene allyl ether sulfate salts, polyoxyalkylene allyl phenyl ether sulfate salts ( For example, polyoxyethylene allyl phenyl ether sulfate), polyoxyalkylene alkyl allyl phenyl ether sulfate, (e.g. polyoxyethylene alkyl allyl phenyl ether sulfate), polyoxyalkylene phenyl ether sulfate (e.g. polyoxyethylene phenyl ether sulfate), polyoxyalkylene polycyclic phenyl ether sulfate, and the like. These compounds can be used alone or in combination of two or more. Examples of the salt are the same as those described in the above (compound having a sulfonic acid (salt) group). For example, anionic surfactants having a sulfate (salt) group are preferably ammonium lauryl sulfate and ammonium polyoxyethylene allylphenyl ether sulfate.

As the anionic surfactant having a sulfate (salt) group, a commercially available product or a synthetic product may be used. Examples of the commercially available products include polyoxyalkylene allylphenyl ether sulfate (salt) (manufactured by Takemoto Yushi Co., Ltd., Nucalgen (registered trademark, hereinafter the same) FS-7S), and polyoxyethylene allylphenyl ether sulfate. (Daiichi Kogyo Seiyaku Co., Ltd., Hytenol (registered trademark, hereinafter the same) NF08), polyoxyethylene alkylallyl phenyl ether sulfate salt (Daiichi Kogyo Seiyaku Co., Ltd., Aqualon (registered trademark, hereinafter the same) HS- 10), polyoxyethylene alkyl ether sulfate (manufactured by Nippon Nyukazai Co., Ltd., Newcol (registered trademark, hereinafter the same) 1020-SN), polyoxyethylene polycyclic phenyl ether sulfate (manufactured by Nippon Nyukazai Co., Ltd., New Cole 707 series), polyoxyethylene allyl ether sulfate (New Cole B4-SN manufactured by Nippon Nyukazai Co., Ltd.), and the like.

(Compound having a phosphonic acid (salt) group)
The compound having a phosphonic acid (salt) group as the anionic surfactant according to the present invention is not particularly limited as long as it is a surfactant having a phosphonic acid (salt) group.

Known compounds such as dodecylphosphonic acid can be used as the compound having a phosphonic acid (salt) group. These compounds can be used alone or in combination of two or more. Examples of the salt are the same as those described in the above (compound having a sulfonic acid (salt) group).

(Compound having a phosphate (salt) group)
The compound having a phosphate (salt) group as the anionic surfactant according to the present invention is not particularly limited as long as it is a surfactant containing a phosphate (salt) group.

Examples of compounds having a phosphoric acid (salt) group include monoalkyl phosphates, alkyl ether phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene allyl phenyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, and the like. mentioned. These compounds can be used alone or in combination of two or more. Examples of the salt are the same as those described in the above (compound having a sulfonic acid (salt) group).

As the compound having a phosphate (salt) group, a commercially available product or a synthetic product may be used. Examples of the commercially available products include polyoxyethylene alkyl ether phosphate (manufactured by Nikko Chemicals Co., Ltd., NIKKOL (registered trademark, hereinafter the same) DLP, DOP, DDP, TLP, TCP, TOP, and TDP series), polyoxy Ethylene allyl phenyl ether phosphate (manufactured by Takemoto Yushi Co., Ltd., phosphoric acid ester (phosphate) series (Nucalgen FS-3AQ, Nucalgen FS-3PG, etc.)).

When the anionic surfactant has an alkyl group, it is preferably a linear or branched alkyl group having 6 to 20 carbon atoms. Further, the anionic surfactant preferably has a structure in which ethylene oxide is added, and the number of moles of ethylene oxide added is preferably 2 to 18, more preferably 3 to 15, and still more preferably 3. ~12.

A commercially available product or a synthetic product may be used as the zeta potential adjusting agent. There are no particular restrictions on the production method when synthesizing, and it can be obtained by a known synthesis method.

The zeta potential adjusters may be used alone or in combination of two or more.

The content (concentration) of the zeta potential adjusting agent (the total amount in the case of two or more types) is not particularly limited, but is preferably 0.001 g/kg or more with respect to the total mass of the surface treatment composition, It is more preferably 0.01 g/kg or more, still more preferably 0.03 g/kg or more, particularly preferably 0.05 g/kg or more, and most preferably 0.08 g/kg or more. When the content of the zeta potential adjuster is 0.001 g/kg or more, the effects of the present invention are further improved. The upper limit of the content of the zeta potential adjusting agent is not particularly limited, but it is preferably 10 g/kg or less, more preferably 5 g/kg or less, and still more preferably 5 g/kg or less, relative to the total mass of the surface treatment composition. is 1 g/kg or less, particularly preferably 0.5 g/kg or less, most preferably 0.3 g/kg or less. When the content of the zeta potential adjusting agent is 10 g/kg or less, the zeta potential adjusting agent itself after the surface treatment can be easily removed.

[Dispersion medium]
The surface treatment composition according to the present invention contains a dispersion medium (solvent) for dissolving or dispersing each component. The dispersion medium preferably contains water, more preferably only water. Also, the dispersion medium may be a mixed solvent of water and an organic solvent for dispersing or dissolving each component. Examples of organic solvents include alcohols such as methanol, ethanol, isopropanol, ethylene glycol, propylene glycol and glycerin; ketones such as acetone; and acetonitrile. Therefore, examples of the dispersion medium include water; alcohols such as methanol, ethanol, isopropanol, ethylene glycol, propylene glycol and glycerin; ketones such as acetone; acetonitrile; Among these, water is preferable as the dispersion medium. Alternatively, these organic solvents may be used without being mixed with water, and each component may be dispersed or dissolved and then mixed with water. These organic solvents can be used alone or in combination of two or more. When a dispersion medium other than water is included, the content of water with respect to the total weight of the dispersion medium is preferably 90% by mass or more and 100% by mass or less, more preferably 99% by mass or more and 100% by mass or less. However, the dispersion medium is most preferably water only.

From the viewpoint of not inhibiting the action of the components contained in the surface treatment composition, the dispersion medium is preferably water containing as few impurities as possible. For example, water having a total content of transition metal ions of 100 ppb or less is preferable. Here, the purity of water can be increased by, for example, removal of impurity ions using an ion exchange resin, removal of foreign matter using a filter, distillation, or other operations. Specifically, deionized water, pure water, ultrapure water, or distilled water obtained by removing foreign matter through a filter after removing impurity ions with an ion exchange resin is more preferable.

[pH and pH adjuster]
The pH of the surface treatment composition according to the present invention is preferably 2 or more and less than 5. When the pH of the surface treatment composition is within the above range, the zeta potential of cerium oxide is positively charged and is electrically attracted to the zeta potential adjuster, resulting in abrasive residue (e.g., cerium oxide). It becomes possible to charge negatively. As a result, the intended effects of the present invention are exhibited more effectively. The surface treatment composition according to the present invention may have a pH of 2 or higher, preferably 2.5 or higher, and more preferably 3 or higher. The surface treatment composition according to the present invention may have a pH of 5 or less, preferably less than 4.5, more preferably 4 or less, and still more preferably 4.5 or less.

The pH of the surface treatment composition can be measured, for example, with a pH meter (for example, manufactured by Horiba Ltd., model number: LAQUA).

The surface treatment composition according to the present invention contains a zeta potential adjusting agent and a dispersion medium as essential components. The pH may be adjusted by adding an adjusting agent (a pH adjusting agent that is a compound different from the above zeta potential adjusting agent). In one embodiment, the surface treatment composition according to the present invention further contains a pH adjuster.

Known acids, bases, or salts thereof can be used as pH adjusters.

Specific examples of acids that can be used as pH adjusters include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, and phosphoric acid, formic acid, and acetic acid. , propionic acid, butyric acid, pentanoic acid, 2-methylbutyric acid, hexanoic acid, 3,3-dimethyl-butyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, heptanoic acid, 2-methylhexanoic acid, octanoic acid, 2- Ethylhexanoic acid, benzoic acid, hydroxyacetic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid, lactic acid, di organic acids such as glycolic acid, 2-furancarboxylic acid, 2,5-furandicarboxylic acid, 3-furancarboxylic acid, 2-tetrahydrofurancarboxylic acid, methoxyacetic acid, methoxyphenylacetic acid, 2-hydroxyisobutyric acid and phenoxyacetic acid; be done. Sulfuric acid, nitric acid, phosphorous acid, phosphoric acid and the like are particularly preferred when an inorganic acid is used as the pH adjuster. When an organic acid is used as the pH adjuster, acetic acid, lactic acid, benzoic acid, hydroxyacetic acid, maleic acid, citric acid, tartaric acid and hydroxyisobutyric acid are preferred, and maleic acid, citric acid and tartaric acid are more preferred.

Bases that can be used as pH adjusters include amines such as aliphatic amines and aromatic amines, ammonium solutions, organic bases such as quaternary ammonium hydroxide, alkali metal hydroxides such as potassium hydroxide, and group 2 elements. , amino acids such as histidine, and ammonia.

The surface treatment composition preferably contains an acid, more preferably an inorganic acid, more preferably at least one selected from the group consisting of sulfuric acid, nitric acid, phosphorous acid and phosphoric acid. is particularly preferred.

A commercially available product or a synthetic product may be used as the pH adjuster. A pH adjuster may be used alone or in combination of two or more. The amount of the pH adjuster to be added is not particularly limited, and may be appropriately adjusted so that the surface treatment composition has a desired pH.

[Other additives]
The surface treatment composition according to one aspect of the present invention may optionally contain other additives in any proportion within the range that does not impair the effects of the present invention. However, since components other than the essential components of the surface treatment composition according to one aspect of the present invention may cause foreign matter, it is desirable not to add them as much as possible. Therefore, it is preferable that the amount of the components other than the essential components to be added is as small as possible, and it is more preferable not to include them. Other additives include, for example, abrasive grains, alkalis, polymer compounds, antifungal agents (preservatives), dissolved gases, reducing agents, oxidizing agents, and alkanolamines. Above all, it is preferable that the surface treatment composition does not substantially contain abrasive grains in order to further improve the foreign matter removing effect. Here, "substantially free of abrasive grains" means that the content of abrasive grains in the entire surface treatment composition is 0.01% by mass or less (lower limit of 0% by mass), and 0.005% by mass. % (lower limit of 0% by mass), and more preferably 0.001% by mass or less (lower limit of 0% by mass).

(Polymer compound)
The surface treatment composition according to one aspect of the present invention may contain a polymer compound. The polymer compound is preferably a polymer compound having an anionic group and having a weight average molecular weight of 1,000 or more. The polymer compound is preferably a polymer having an acid (salt) group and having a weight average molecular weight of 1,000 or more. The polymer compound has at least one functional group selected from the group consisting of a sulfonic acid (salt) group, a phosphonic acid (salt) group and a phosphoric acid (salt) group, having a weight average molecular weight of 1,000 or more. More preferably, it is a polymer compound.

The polymer compounds can be used singly or in combination of two or more. Moreover, a commercial product may be used for a high molecular compound, and a synthetic product may be used.

When the surface treatment composition contains a polymer compound, the lower limit of the content of the polymer compound is preferably 0.01% by mass or more, preferably 0.03% by mass or more, based on the total mass of the surface treatment composition as 100% by mass. is more preferable, and 0.05% by mass or more is even more preferable. Further, the upper limit of the content of the polymer compound in the surface treatment composition is preferably 5% by mass or less, more preferably 1% by mass or less, and 0.5% by mass, based on the total mass of the surface treatment composition being 100% by mass. % or less is more preferable. In addition, when a surface treatment composition contains 2 or more types of high molecular compounds, content of a high molecular compound intends these total amounts.

[Antifungal agent]
The surface treatment composition according to the present invention preferably contains an antifungal agent (preservative). The antifungal agent (preservative) that can be used when the surface treatment composition according to the present invention contains an antifungal agent (preservative) is not particularly limited and can be appropriately selected according to the type of polymer. Specific examples include isothiazolin-based preservatives such as 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one, and phenoxyethanol.

The antifungal agents (preservatives) may be used alone or in combination of two or more.

When the surface treatment composition contains an antifungal agent (preservative), the lower limit of the content (concentration) of the antifungal agent (preservative) is not particularly limited, but is preferably 0.0001% by mass or more. , is more preferably 0.001% by mass or more, still more preferably 0.005% by mass or more, and particularly preferably 0.01% by mass or more. The upper limit of the content (concentration) of the antifungal agent (preservative) is not particularly limited, but is preferably 5% by mass or less, more preferably 1% by mass or less, and 0.5% by mass. It is more preferably 0.1% by mass or less, and particularly preferably 0.1% by mass or less. That is, the content (concentration) of the antifungal agent (preservative) in the surface treatment composition is preferably 0.0001% by mass or more and 5% by mass or less, more preferably 0.001% by mass or more and 1% by mass or less, It is more preferably 0.005% by mass or more and 0.5% by mass or less, and particularly preferably 0.01% by mass or more and 0.1% by mass or less. Within such a range, a sufficient effect for inactivating or destroying microorganisms can be obtained. In addition, when the surface treatment composition contains two or more antifungal agents (preservatives), the above-mentioned content intends the total amount thereof.

That is, in one embodiment of the present invention, the surface treatment composition is substantially composed of at least one selected from the group consisting of a zeta potential adjuster, a pH adjuster, water, an antifungal agent, an organic solvent, and a polymer compound. configured to In one embodiment of the present invention, the surface treatment composition consists essentially of a zeta potential modifier, a pH modifier and water, and at least one of an antifungal agent and an organic solvent. In one embodiment of the invention, the surface treatment composition consists essentially of a zeta potential modifier, a pH modifier and water. In this embodiment, "the surface treatment composition is substantially composed of X" means that the total content of X is 100% by mass of the total mass of the surface treatment composition (with respect to the surface treatment composition ), which means more than 99% by mass (upper limit: 100% by mass). Preferably, the surface treatment composition consists of X (the above total content = 100% by mass). For example, "the surface treatment composition is substantially composed of at least one of a zeta potential adjuster, a pH adjuster and water, an antifungal agent, an organic solvent and a polymer compound" means a zeta potential adjuster, The total content of the pH adjuster and water, as well as the antifungal agent, organic solvent and polymer compound exceeds 99% by mass when the total mass of the surface treatment composition is 100% by mass (relative to the surface treatment composition). (Upper limit: 100% by mass), and the surface treatment composition is composed of at least one of a zeta potential adjuster, a pH adjuster and water, an antifungal agent, an organic solvent and a polymer compound (the above total content = 100% by mass).

The surface treatment composition according to the present invention controls the zeta potential of the silicon oxide contained in the polished object to be negative, and the zeta potential of the inorganic oxide abrasive grains adhering to the polished object to be - It can be controlled to 30 mV or less. The reason why such control is possible is that the zeta potential adjusting agent contained in the surface treatment composition has a high affinity for silicon oxide and inorganic oxide abrasive grains contained in the polished object, and silicon oxide And it is thought that it tends to adhere to the surface of inorganic oxide abrasive grains. It is believed that the zeta potential adjuster negatively charges the silicon oxide and inorganic oxide abrasive grains and leads the zeta potential of the inorganic oxide abrasive grains to −30 mV or less.

[Method for producing surface treatment composition]
The method for producing the surface treatment composition is not particularly limited. For example, it can be produced by mixing a zeta potential adjusting agent having an sp value of more than 9 and not more than 11 and having a negative functional group with a dispersion medium (eg, water). That is, according to another aspect of the present invention, the above-described surface including mixing a zeta potential adjusting agent having an sp value of more than 9 and not more than 11 and having a negative functional group with a dispersion medium A method of making the treatment composition is also provided. The type, addition amount, etc. of the zeta potential adjusting agent are as described above. Furthermore, in the method for producing a surface treatment composition according to one aspect of the present invention, other components than the zeta potential adjusting agent and the dispersion medium may be further mixed, if necessary. The types, addition amounts, etc. of these are as described above.

The addition order and addition method of each component contained in the surface treatment composition are not particularly limited. Each of the above ingredients may be added together or separately, stepwise or continuously. Also, the mixing method is not particularly limited, and a known method can be used. Preferably, the method for producing the surface treatment composition includes sequentially adding a zeta potential adjusting agent, a dispersion medium, and optionally other components, and stirring in the dispersion medium. In addition, the method for producing the surface treatment composition may further include measuring and adjusting the pH of the surface treatment composition so as to obtain a desired pH.

Here, the residue on the surface of the polished object to be polished that is removed by the surface treatment composition according to the present invention is adhered to the polished object by the polishing treatment. That is, the inorganic oxide abrasive grains are residues derived from the polishing composition, and the pad scraps (for example, polyurethane) are residues derived from the polishing pad used in the polishing process. Therefore, the polishing composition and the polishing treatment from which these residues are derived will be described. In other words, how the polished object to be surface-treated is obtained in the surface treatment method of the present invention will be described.

[Polishing composition]
The polishing composition contains inorganic oxide abrasive grains, a dispersion medium, and, if necessary, additives. In the present invention, the composition of the polishing composition is not particularly limited except that it essentially contains inorganic oxide abrasive grains and a dispersion medium.

[Abrasive]
Examples of abrasive grains (inorganic oxide abrasive grains) contained in the polishing composition include silicon oxide (silica), aluminum oxide (alumina), cerium oxide (ceria), zirconium oxide (zirconia), and titanium oxide (titania). Particles made of inorganic oxides (metal oxides) such as These metal oxides may be surface-modified. For example, it may be an anion-modified inorganic oxide in which an organic acid such as carboxylic acid or sulfonic acid is immobilized. Such an anion-modified inorganic oxide is preferably an anion-modified silicon oxide in which an organic acid such as carboxylic acid or sulfonic acid is immobilized. Silica is more preferred. Such immobilization of the organic acid on the surface of the inorganic oxide is performed, for example, by chemically bonding the functional group of the organic acid to the surface of the inorganic oxide. Mere coexistence of an inorganic oxide and an organic acid does not accomplish the fixation of the organic acid to the inorganic oxide. For example, if sulfonic acid, which is a kind of organic acid, is immobilized on colloidal silica, for example, "Sulfonic acid-functionalized silica through quantitative oxidation of thiol groups", Chem. Commun. 246-247 (2003) described in method can be done. Specifically, sulfonic acid is immobilized on the surface by coupling a silane coupling agent having a thiol group such as 3-mercaptopropyltrimethoxysilane to colloidal silica and then oxidizing the thiol group with hydrogen peroxide. anion-modified colloidal silica can be obtained. Alternatively, if the carboxylic acid is immobilized on colloidal silica, for example, "Novel Silane Coupling Agents Containing a Photolabile 2-Nitrobenzyl Ester for Introduction of a Carboxy Group on the Surface of Silica
Gel", Chemistry Letters, 3, 228-229 (2000). Specifically, a silane coupling agent containing a photoreactive 2-nitrobenzyl ester is coupled to colloidal silica. Then, by irradiating with light, anion-modified colloidal silica having carboxylic acid immobilized on the surface can be obtained.Among these, anion-modified silicon oxide having sulfonic acid immobilized on the surface (in this specification, Anion-modified colloidal silica with sulfonic acid immobilized on its surface (also referred to herein as sulfonic acid-modified colloidal silica) is more preferable.Immobilized on the surface of an inorganic oxide The organic acid used may be in the acid state or in the salt state.

The abrasive grains (inorganic oxide abrasive grains) are more preferably at least one of anion-modified silicon oxide abrasive grains and cerium oxide abrasive grains from the viewpoint of the removal effect by the surface treatment composition, and anion-modified colloidal silica abrasive grains. and cerium oxide abrasive grains are more preferred, and cerium oxide abrasive grains are particularly preferred. Anion-modified silicon oxide abrasive grains and cerium oxide abrasive grains tend to form an affinity layer when in contact with the surface treatment composition, and are easily removed from the surface of the polished object by washing or the like after the surface treatment.

Therefore, according to a preferred embodiment of the surface treatment method of the present invention, the inorganic oxide abrasive grains contained in the residue are at least one of anion-modified silicon oxide abrasive grains and cerium oxide abrasive grains, and are , the zeta potential of at least one of the anion-modified silicon oxide abrasive grains and the cerium oxide abrasive grains is controlled to −30 mV or less. According to a more preferred embodiment of the surface treatment method of the present invention, the inorganic oxide abrasive grains contained in the residue are cerium oxide abrasive grains, and the surface treatment composition reduces the zeta potential of the cerium oxide abrasive grains to −30 mV. Control below.

Although the lower limit of the average primary particle size of the abrasive grains is not particularly limited, it is preferably 5 nm or more, more preferably 7 nm or more, and more preferably 10 nm or more. Within this range, a desired polishing rate can be easily obtained. Although the upper limit of the average primary particle size of the abrasive grains is not particularly limited, it is preferably 50 nm or less, more preferably 40 nm or less, and even more preferably 30 nm or less. Within this range, the effect of the surface treatment composition according to the present invention is exhibited more effectively. The value of the average primary particle size of the abrasive grains can be calculated based on the specific surface area of the abrasive grains measured by the BET method, assuming that the particle shape of the inorganic oxide abrasive grains is a true sphere. .

Although the lower limit of the average secondary particle size of the abrasive grains is not particularly limited, it is preferably 5 nm or more, more preferably 10 nm or more, and even more preferably 20 nm or more. Within this range, a desired polishing rate can be easily obtained. The upper limit of the average secondary particle size of the abrasive grains is not particularly limited, but is preferably 100 nm or less, more preferably 90 nm or less, and even more preferably 80 nm or less. Within this range, the effect of the surface treatment composition according to the present invention is exhibited more effectively. The value of the average secondary particle size of abrasive grains can be calculated based on a light scattering method using laser light.

Abrasive grains may be synthetic or commercially available.

The lower limit of the content (concentration) of the abrasive grains in the polishing composition is not particularly limited, but it is preferably more than 0.01% by mass, preferably 0.1% by mass, based on the total mass of the polishing composition. It is more preferably 0.5% by mass or more, and more preferably 0.5% by mass or more. Within this range, a desired polishing rate can be easily obtained. The upper limit of the content (concentration) of the abrasive grains is not particularly limited, but it is preferably 10% by mass or less, more preferably 5% by mass or less, relative to the total mass of the polishing composition. , 3% by mass or less. Within this range, the abrasive grains remaining on the surface of the polished object to be polished are more effective due to the surface treatment composition.

[Other ingredients]
The polishing composition may contain components (additives) other than the inorganic oxide abrasive grains and the dispersion medium, such as pH adjusters, surfactants, wetting agents, chelating agents, preservatives, Components used in known polishing compositions, such as antifungal agents, dissolved gases, oxidizing agents and reducing agents, can be appropriately selected.

[Polishing]
A polishing process performed using a polishing composition is a process of polishing an object to be polished to form a polished object. In the polishing process, the object to be polished is polished using a polishing device.

The polishing treatment is not particularly limited as long as it polishes the object to be polished, but chemical mechanical polishing (CMP) treatment is preferred. Further, the polishing process may be a polishing process consisting of a single process or a polishing process consisting of a plurality of processes. Examples of the polishing process comprising a plurality of processes include a process of performing a final polishing process after a preliminary polishing process (rough polishing process), a process of performing a secondary polishing process once or twice or more after a primary polishing process, A process of performing a final polishing process after that, etc. are mentioned. Surface treatment using the surface treatment composition according to the present invention is preferably performed after the final polishing step.

As a polishing device, a general polishing device is used that has a holder that holds the object to be polished, a motor that can change the rotation speed, etc., and a polishing surface plate that can be attached with a polishing pad (abrasive cloth). can do. As the polishing device, either a single-sided polishing device or a double-sided polishing device may be used.

As the polishing pad used in the polishing process according to the present invention, general non-woven fabric, polyurethane, porous fluororesin, and the like can be used without particular limitation. Preferably, the polishing pad is polyurethane.

That is, in the present invention, components derived from the polishing pad may adhere to the surface of the polished object to be polished. In this case, when the polishing pad is made of polyurethane, the zeta potential of the polyurethane, which is the residue adhered to the surface of the object that has been polished by the surface treatment composition according to the present invention, can be controlled to −30 mV or less. This allows the residue (polyurethane) to be removed efficiently.

In the surface treatment method of the present invention, it is preferable that the Shore A hardness of the polishing pad used for the polishing treatment is 40° or more and 100° or less. The Shore A hardness of the polishing pad used for polishing treatment is preferably 40° or higher, more preferably 60° or higher, even more preferably 70° or higher, even more preferably 75° or higher, particularly preferably 80° or higher, and 85°. The above is most preferable. The Shore A hardness of the polishing pad used for polishing treatment is preferably 100° or less, more preferably 99° or less, even more preferably 97° or less, even more preferably 95° or less, and particularly preferably 93° or less. When the Shore A hardness of the polishing pad used in the polishing process is within the above range, the polishing pad and the object to be polished are brought into contact with each other with an appropriate pressure, and not only can the polishing be efficiently performed, but also the polished object can be polished. There is an effect that it is difficult for residues to remain on the surface of the object to be polished.

The Shore A hardness of the polishing pad is a value measured based on a type A durometer in compliance with JIS K 6253-3:2012.

It is preferable that the polishing pad is grooved so that the polishing liquid is accumulated.

Polishing conditions are not particularly limited. For example, the number of rotations of the polishing surface plate and the number of rotations of the head (carrier) are preferably 10 rpm (0.17 s ^-1 ) or more and 100 rpm (1.7 s ^-1 ) or less. The pressure (polishing pressure) applied to the surface is preferably 0.5 psi (3.5 kPa) or more and 10 psi (69 kPa) or less. The method of supplying the polishing composition to the polishing pad is also not particularly limited, and for example, a method of continuously supplying the composition with a pump or the like (overflow) is employed. Although there is no limit to the supply amount, it is preferable that the surface of the polishing pad is always covered with the polishing composition, and the amount is preferably 10 mL/min or more and 5000 mL/min or less. The polishing time is also not particularly limited, but it is preferably 5 seconds or more and 180 seconds or less for the step using the polishing composition.

[Surface treatment method]
The present invention is a surface treatment method comprising treating the surface of a polished object using the surface treatment composition.

According to the surface treatment method according to one aspect of the present invention, it is possible to sufficiently remove residues remaining on the surface of a polished object to be polished. That is, according to another aspect of the present invention, there is provided a method for reducing residues on the surface of a polished object, comprising surface-treating the polished object using the surface treatment composition.

A surface treatment method according to one aspect of the present invention is carried out by a method in which the surface treatment composition according to the present invention is brought into direct contact with a polished object containing silicon oxide. Examples include, but are not limited to, a method using a rinse polishing treatment, a method using a cleaning treatment, and the like. Accordingly, the surface treatment method according to one embodiment of the present invention is a rinse polishing treatment method or a cleaning treatment method. Moreover, the surface treatment composition according to one embodiment of the present invention is a rinse polishing composition or a cleaning composition. Rinsing treatment and cleaning treatment are performed to remove foreign substances (inorganic oxide abrasive grains, residues such as pad dust, metal contamination, etc.) on the surface of the polished object to obtain a clean surface.

The surface treatment composition according to the present invention is particularly suitable for use in rinse polishing. Rinse polishing is performed on a polishing surface plate (platen) to which a polishing pad is attached. Represents the process of removing residues. A specific example of the rinse polishing treatment is not particularly limited, but after performing polishing (for example, final polishing, finish polishing, etc.) on the polishing object, the polished polishing object is placed on the polishing surface plate (platen) of the polishing apparatus. A process is performed in which the polished object to be polished and the polishing pad are brought into contact with each other in the installed state, and the polished object to be polished and the polishing pad are caused to slide relative to each other while supplying the surface treatment composition to the contact portion. mentioned. The rinse polishing process may be performed on the same polishing surface plate as the polishing surface plate used for polishing the object to be polished (for example, final polishing, final polishing, etc.), or may be performed on the polishing surface plate used for the polishing. It may be performed on a polishing platen different from the polishing platen. Among these, the rinse polishing process is preferably performed on a polishing surface plate different from the polishing surface plate used for polishing the object to be polished (for example, final polishing, final polishing, etc.).

A rinse polishing treatment is performed by directly contacting the surface treatment composition according to the present invention with a polished polishing object containing silicon oxide. It is believed that the action of the surface treatment composition negatively charges the silicon oxide, the inorganic oxide abrasive grains, and in some cases, the polyurethane due to the adhesion of the zeta potential control agent. Then, by the frictional force (physical action) of the polishing pad and the action of the surface treatment composition, the inorganic oxide abrasive grains, and optionally polyurethane, are removed from the surface of the polished object containing silicon oxide, and , redeposition is prevented. At this time, by utilizing the friction with the polishing pad (the friction between the polishing pad and the residue) on the polishing surface plate (platen), residues such as inorganic oxide abrasive grains and pad scraps are more effectively removed. . After the rinsing treatment, a process such as washing with water (post-washing treatment described later) is performed, whereby the zeta potential adjusting agent on the surface of the silicon nitride is easily removed. As a result, it is possible to obtain a polished object containing silicon oxide in which residue containing inorganic oxide abrasive grains is remarkably reduced.

The rinsing polishing process is not particularly limited, but is generally equipped with a holder that holds the object to be polished, a motor that can change the number of rotations, and a polishing surface plate that can be attached with a polishing pad (abrasive cloth). It is preferable to use a suitable polishing apparatus. As the polishing device, either a single-sided polishing device or a double-sided polishing device may be used. As the polishing pad, general non-woven fabric, polyurethane, porous fluororesin, and the like can be used without particular limitation, but polyurethane is preferable from the viewpoint of further reducing residue. It is preferable that the polishing pad is grooved so that the polishing liquid is accumulated. Further, when the chemical mechanical polishing and the rinse polishing treatment are performed using the same polishing apparatus, the polishing apparatus, in addition to the polishing composition ejection nozzle, ejects the surface treatment composition according to one embodiment of the present invention. A nozzle is preferably provided.

Here, the processing conditions are not particularly limited, but for example, the pressure between the polished object to be polished and the polishing pad is preferably 0.5 psi (3.5 kPa) or more and 10 psi (69 kPa) or less. The head rotation speed is preferably 10 rpm (0.17 s ^-1 ) or more and 100 rpm (1.7 s ^-1 ) or less. Further, the rotation speed of the polishing surface plate (platen) is preferably 10 rpm (0.17 s ^-1 ) or more and 100 rpm (1.7 s ^-1 ) or less. There is no limit to the supply amount of free-flowing, but it is preferable that the surface of the polished object to be polished is covered with the surface treatment composition, for example, 10 mL/min or more and 5000 mL/min or less. Also, the surface treatment time is not particularly limited, but it is preferably 5 seconds or more and 180 seconds or less. In the present invention, the surface treatment time is preferably 20 seconds or more, more preferably 30 seconds or more, more preferably 45 seconds, since an increase in the number of residues is suppressed even by long-term surface treatment. It is more preferable that it is above. The upper limit of surface treatment time is usually within 5 minutes.

The surface treatment composition according to the present invention is also suitable for cleaning treatment. As used herein, the term “cleaning treatment” refers to cleaning of the surface of the polished object mainly by the action of the surface treatment composition, which is performed after the polished object has been removed from the polishing surface plate (platen). Represents the process of removing residues. As a specific example of the cleaning treatment, after polishing (for example, final polishing, final polishing, etc.) the object to be polished, or after performing rinsing treatment following polishing, the polished object is polished. A treatment of removing the object from the board (platen) and contacting the object to be polished with the surface treatment composition is exemplified. A means for applying a frictional force (physical action) to the surface of the polished object while the surface treatment composition and the polished object are in contact may be further used.

The cleaning treatment method is not particularly limited, but for example, a method of immersing the polished object to be polished in the surface treatment composition and, if necessary, subjecting it to ultrasonic treatment, washing while holding the polished object to be polished. Examples include a method of contacting a brush with a polished object to be polished and rubbing the surface of the polished object with a brush while supplying the surface treatment composition to the contact portion.

The cleaning apparatus is not particularly limited, but for example, a batch-type cleaning apparatus for simultaneously surface-treating a plurality of polished objects housed in a cassette, or a holder in which a single polished object is mounted. Examples include a single-wafer cleaning apparatus for surface treatment, and a polishing apparatus equipped with cleaning equipment for removing a polished object from a polishing platen (platen) and then scrubbing the object with a cleaning brush. Here, as the polishing device, a general polishing device having a holder for holding the polished object to be polished, a motor capable of changing the number of revolutions, a cleaning brush, and the like can be used. Moreover, the cleaning brush is not particularly limited, but for example, a brush made of resin such as PVA (polyvinyl alcohol) can be used.

The cleaning conditions are not particularly limited, and can be appropriately set according to the type of polished object to be polished and the type and amount of impurities to be removed.

[Post-washing treatment]
As a surface treatment method according to an embodiment of the present invention, after the surface treatment, the polished object to be polished may be further subjected to a cleaning treatment. This cleaning process is referred to herein as a post-cleaning process. Specific examples of the post-cleaning treatment are not particularly limited. Examples include a method of rubbing the polished object after surface treatment with a cleaning brush while pouring the water over it. The method, apparatus, and conditions for the post-cleaning treatment are not particularly limited, but the description of the cleaning treatment can be referred to, for example. The water used for the post-washing treatment is not particularly limited, but it is particularly preferable to use deionized water.

By performing the surface treatment with the surface treatment composition according to one embodiment of the present invention, the residue is extremely easily removed. Therefore, after the surface treatment with the surface treatment composition according to one embodiment of the present invention, the residue can be removed very well by further washing treatment with water.

After post-cleaning, the polished object to be polished is preferably dried by using a spin dryer or the like to remove water droplets adhering to the surface. Alternatively, the surface of the polished object may be dried by air blow drying.

[Method for manufacturing semiconductor substrate]
The surface treatment method of the present invention is suitably applicable when the polished object to be polished is a polished semiconductor substrate. That is, according to another embodiment of the present invention, the polished object to be polished is a polished semiconductor substrate, and the surface of the polished object to be polished is treated by the surface treatment method described above. A method of manufacturing a semiconductor substrate is also provided, comprising:

That is, in the method for manufacturing a semiconductor substrate of the present invention, the polished object to be polished is a semiconductor substrate, and a polishing composition containing inorganic oxide abrasive grains is used to prepare an unpolished semiconductor substrate containing silicon oxide. a polishing step of obtaining a polished semiconductor substrate by polishing; and a surface treatment step of reducing residue containing the inorganic oxide abrasive grains on the surface of the polished semiconductor substrate by the surface treatment method of the present invention. .

According to one embodiment of the present invention, in the method for manufacturing a semiconductor substrate, the inorganic oxide abrasive grains include cerium oxide abrasive grains, and the surface treatment composition used in the surface treatment step reduces the cerium oxide This includes controlling the zeta potential of the abrasive grains to −30 mV or less.

According to one embodiment of the present invention, in the method for manufacturing a semiconductor substrate, the polishing step includes using a polishing pad made of polyurethane, and the residue further includes the polyurethane and is used in the surface treatment step. controlling the zeta potential of the polyurethane to −30 mV or less with the surface treatment composition applied.

The details of the semiconductor substrate to which such a manufacturing method is applied are as described for the polished object to be surface-treated with the surface treatment composition.

In addition, as a method for manufacturing a semiconductor substrate, the surface of a polished semiconductor substrate is surface treated using the surface treatment composition according to one embodiment of the present invention, or surface treated by the surface treatment method according to one embodiment of the present invention. It is not particularly limited as long as it includes a step (surface treatment step).

[Semiconductor substrate manufacturing system]
The present invention also relates to a semiconductor substrate manufacturing system comprising an object to be polished containing silicon oxide, a polishing pad, a polishing composition containing inorganic oxide abrasive grains, and the surface treatment composition described above. Thus, according to another aspect of the present invention, there is provided a semiconductor substrate manufacturing system comprising a polishing object containing silicon oxide, a polishing pad, a polishing composition containing cerium oxide abrasive grains, and a surface treatment composition. A semiconductor substrate manufacturing system is also provided, wherein the surface of the object to be polished after polishing with the polishing composition and the polishing pad is brought into contact with the surface treatment composition.

Preferred embodiments of the polishing object containing silicon oxide, the polishing pad, the polishing composition containing inorganic oxide abrasive grains, and the surface treatment composition, which are applied to the semiconductor substrate manufacturing system of the present invention, are described above. Since it is the same, the explanation is omitted.

In one embodiment of the present invention, a system for manufacturing a semiconductor substrate is such that both surfaces of a polished object are brought into contact with a polishing pad and a surface treatment composition to simultaneously treat both surfaces of the polished object. Alternatively, only one side of the polished object may be brought into contact with the polishing pad and the surface treatment composition to surface-treat only one side of the polished object. Since the preferred embodiment of the surface treatment is the same as above, the description is omitted.

[Residue removal effect]
It is preferable that the surface treatment composition according to one aspect of the present invention has a higher effect of removing residues on the surface of the polished object. That is, it is preferable that the number of residues remaining on the surface of the polished object to be polished is as small as possible when the surface treatment composition is used to treat the surface of the polished object. Specifically, when the polished object to be polished is surface-treated with the surface treatment composition, the total residue) is preferably 10,000 or less, more preferably 7,000 or less, and 5,000 or less. Even more preferably, it is particularly preferably 3000 or less, and particularly preferably 2000 or less. On the other hand, since it is preferable that the total number of residues is as small as possible, the lower limit is not particularly limited, but is substantially 100 or more.

Further, when the polished object to be polished is surface-treated with the surface treatment composition, the number of residual abrasive grains is preferably 6,000 or less, more preferably 4,000 or less, and even more preferably 3,500 or less. , is more preferably 2500 or less, and particularly preferably 2000 or less. On the other hand, since the number of residual abrasive grains is preferably as small as possible, the lower limit is not particularly limited, but is, for example, 50 or more.

When the polished object to be polished is surface-treated with the surface treatment composition, the number of polyurethane residues is preferably 4000 or less, more preferably 3000 or less, even more preferably 2500 or less, 1500 or less is particularly preferable. On the other hand, since the number of polyurethane residues is preferably as small as possible, the lower limit is not particularly limited, but is, for example, 50 or more.

For the numbers of residues described above, the values measured by the method described in Examples after the surface treatment is performed by the method described in Examples are adopted.

While the embodiments of the invention have been described in detail, it is clear that this is to be considered illustrative and exemplary rather than limiting, and the scope of the invention is to be construed by the appended claims. is.

The present invention includes the following aspects and forms.

[1] A surface treatment method for reducing residue containing inorganic oxide abrasive grains on the surface of a polished object containing silicon oxide using a surface treatment composition,
The surface treatment composition comprises a zeta potential adjusting agent having an sp value of more than 9 and not more than 11 and having a negatively charged functional group, and a dispersion medium,
A surface treatment method, comprising controlling the zeta potential of the silicon oxide to be negative and the zeta potential of the inorganic oxide abrasive grains to −30 mV or less with the surface treatment composition.

[2] The surface treatment method according to [1] above, wherein the inorganic oxide abrasive grains contain cerium oxide abrasive grains, and the zeta potential of the cerium oxide abrasive grains is controlled to −30 mV or less by the surface treatment composition. .

[3] The surface treatment method according to [1] or [2] above, wherein the residue further comprises polyurethane, and the surface treatment composition further comprises controlling the zeta potential of the polyurethane to −30 mV or less. .

[4] The surface treatment method according to any one of [1] to [3] above, wherein the zeta-potential adjusting agent is an anionic surfactant having a molecular weight of less than 1,000.

[5] The anionic surfactant has at least one functional group selected from the group consisting of a sulfonic acid (salt) group, a sulfuric acid (salt) group, a phosphonic acid (salt) group, and a phosphoric acid (salt) group. The surface treatment method according to [4] above.

[6] The surface treatment method according to any one of [1] to [5] above, wherein the surface treatment composition further contains a pH adjuster.

[7] The surface treatment method according to any one of [1] to [6] above, wherein the surface treatment composition has a pH value of 2 or more and less than 5.

[8] The surface treatment method according to any one of [1] to [7] above, which is a rinse polishing treatment method or a cleaning treatment method.

[9] The polished object to be polished is a polished semiconductor substrate,
a polishing step of obtaining a polished semiconductor substrate by polishing an unpolished semiconductor substrate containing silicon oxide using a polishing composition containing inorganic oxide abrasive grains;
a surface treatment step of reducing residue containing the inorganic oxide abrasive grains on the surface of the polished semiconductor substrate by the surface treatment method according to any one of claims 1 to 8;
A method of manufacturing a semiconductor substrate, comprising:

[10] The inorganic oxide abrasive grains include cerium oxide abrasive grains,
The method for producing a semiconductor substrate according to [9] above, comprising controlling the zeta potential of the cerium oxide abrasive grains to −30 mV or less by the surface treatment composition used in the surface treatment step.

[11] The polishing step includes using a polyurethane polishing pad,
The residue further contains the polyurethane,
The method for manufacturing a semiconductor substrate according to [9] or [10] above, further comprising controlling the zeta potential of the polyurethane to −30 mV or less by the surface treatment composition used in the surface treatment step.

[12] The method for manufacturing a semiconductor substrate according to [11] above, wherein the polishing pad has a Shore A hardness of 40° or more and 100° or less.

[13] A surface treatment composition used for reducing residue containing inorganic oxide abrasive grains on the surface of a polished object containing silicon oxide, comprising:
A zeta potential adjusting agent having an sp value of more than 9 and not more than 11 and having a negatively charged functional group, and a dispersion medium,
A surface treatment composition having a function of controlling the zeta potential of the silicon oxide to be negative and controlling the zeta potential of the inorganic oxide abrasive grains to −30 mV or less.

[14] The above [13], wherein the inorganic oxide abrasive grains contain cerium oxide abrasive grains, and the surface treatment composition has a function of controlling the zeta potential of the cerium oxide abrasive grains to −30 mV or less. surface treatment composition.

[15] The surface treatment composition according to [13] or [14] above, wherein the residue further contains polyurethane, and the surface treatment composition further has a function of controlling the zeta potential of the polyurethane to −30 mV or less. .

[16] The surface treatment composition according to any one of [13] to [15] above, which is a rinse polishing composition or a cleaning composition.

[17] A semiconductor substrate comprising an object to be polished containing silicon oxide, a polishing pad, a polishing composition containing inorganic oxide abrasive grains, and the surface treatment composition according to any one of [13] to [16] above. A manufacturing system for
A system for manufacturing a semiconductor substrate, wherein the surface of the object to be polished after polishing with the polishing composition and the polishing pad is brought into contact with the surface treatment composition.

The present invention will be described in more detail with the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples. Unless otherwise specified, "%" and "parts" mean "% by mass" and "parts by mass" respectively. Further, in the following examples, unless otherwise specified, the operations were carried out under the conditions of room temperature (20 to 25° C.)/relative humidity of 40 to 50% RH. Furthermore, in the following examples, "TEOS substrate" means a substrate having a silicon oxide film produced using tetraethyl orthosilicate as a precursor.

[Preparation of surface treatment composition]
[Preparation of surface treatment composition A1]
The entire composition is 100 parts by mass, POE allylphenyl ether ammonium sulfate (product name: Hytenol (registered trademark, hereinafter the same) NF08, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as a zeta potential adjuster, and nitric acid as a pH adjuster. and water (deionized water) as a dispersion medium to prepare a surface treatment composition A1. The amount (content) of the zeta potential adjuster to be added is 0.1 g/kg with respect to the total mass of the surface treatment composition A1, and the amount (content) of the pH adjuster to be added is the amount (content) of the surface treatment composition. The amount was such that the pH of A1 was 3 (liquid temperature: 25°C). The pH was measured using a pH meter (manufactured by Horiba, Ltd., product name: LAQUA (registered trademark)).

[Preparation of surface treatment compositions A2 to A6]
The surface treatment composition except that the type of zeta potential adjuster was changed as shown in Table 1 below, and the amount of the pH adjuster was changed so that the pH of the resulting surface treatment composition was the pH shown in Table 1 below. Surface treatment compositions A2 to A6 were prepared in the same manner as in the preparation of product A1.

[Preparation of Surface Treatment Compositions B1 to B9]
Using the zeta potential adjuster or additive described in Table 1 (a compound used instead of the zeta potential adjuster is referred to as an additive), the type and content of the zeta potential adjuster or additive are shown in Table 1 below. In the same manner as in the preparation of the surface treatment composition A1, except that the amount of the pH adjuster was changed so that the resulting surface treatment composition had a pH shown in Table 1 below, each surface Treatment compositions B1-B9 were prepared.

Surface treatment compositions A1 to A6 are surface treatment compositions used in Examples, and surface treatment compositions B1 to B9 are surface treatment compositions used in Comparative Examples.

Details of the zeta potential adjusting agents and additives used in the surface treatment compositions A1 to A6 and B1 to B9 are shown below. Table 1 shows the sp values of the zeta potential regulators and additives used. The sp value is a value calculated by the Fedors method (reference: RF Fedors, Polym. Eng. Sci., 14 [2] 147 (1974)).

・ POE allyl phenyl ether ammonium sulfate, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product number: Hitenol NF08 (EO = 10)
・Alkyl diphenyl ether disulfonate, manufactured by Takemoto Oil Co., Ltd., product number: Pionin A-43-S (alkyl = C12)
・ POE allyl phenyl ether phosphate amine salt, manufactured by Takemoto Oil Co., Ltd., product number: Nucalgen FS-3AQ (mixture of EO = 3 to 10)
・ Ammonium lauryl sulfate, manufactured by Kao Corporation, product number: Emar AS-25R
・ Sodium lauryl glycol carboxylate, manufactured by Sanyo Chemical Industries, Ltd., product number: Beaulight SHAA
・ Polyoxyethylene tridecyl ether acetate Na, manufactured by Nikko Chemicals Co., Ltd., product number: NIKKOL ECTD-3NEX
・3-amino-1,5-naphthalenedisulfonic acid 2Na
・ Polyvinyl alcohol (PVA), Mw = 10,000: manufactured by Japan Vinyl Acetate and Poval Co., Ltd., product number: JMR-10HH
· Polyglycerin lauryl ether (PGLE), Mw = 2,000: manufactured by Daicel Corporation, product number: Sermolis (registered trademark) B044 (glycerin 20-mer)
- POE lauryl ether, manufactured by Nippon Emulsion Co., Ltd., product number: EMALEX 709 (EO=9).

[Examples 1 to 24, Comparative Examples 1 to 27 and Reference Examples 1 to 5]
In order to evaluate the performance of the obtained surface treatment compositions A1 to A6 and B1 to B9, a CMP step for the polishing object and a rinse polishing step for the polished polishing object obtained through the CMP step were carried out as follows. carried out. The rinsing and polishing step is carried out using the surface treatment compositions A1 to A6 and B1 to B9.

[CMP process]
First, a CMP process was performed on the object to be polished. A TEOS substrate or a SiN substrate was used as the object to be polished, and the following two types of polishing compositions were prepared.

"Polishing composition"
Polishing composition C1 (polishing composition using _CeO2 abrasive grains as abrasive grains)
Colloidal ceria (HC30 manufactured by Solvay) (average primary particle size: 30 nm, average secondary particle size: 70 nm, 30 wt% aqueous dispersion): 1% by mass
Ammonium polyacrylate (Aron A-30SL manufactured by Toagosei Co., Ltd.) (Mw: 6000, 40% aqueous solution): 0.6% by mass
30% maleic acid aqueous solution (manufactured by Kanto Kagaku Co., Ltd.): 0.2% by mass
Water: balance (adjusted to pH 4).

- Polishing composition C2 (polishing composition using _SiO2 abrasive grains as abrasive grains)
Anion-modified colloidal silica ("Sulfonic acid-functionalized silica through quantitative oxidation of thiol groups", Chem. Commun. 246-247 (2003) prepared by the method described in sulfonic acid-modified colloidal silica) (average primary particle size: 35 nm , Average secondary particle size: 70 nm): 2% by mass
30% maleic acid aqueous solution (manufactured by Kanto Chemical Co., Ltd.): 0.002% by mass
Ammonium sulfate (manufactured by Kanto Chemical Co., Ltd.): 0.25% by mass
Water: balance (adjusted to pH 3).

"CMP process"
A TEOS substrate or a SiN substrate, which is a semiconductor substrate, was used as an object to be polished, and the polishing composition was used to perform polishing under the following conditions. Here, the TEOS substrate used a 300 mm wafer, and the SiN substrate used a 300 mm wafer;
・TEOS substrate (300mm wafer, manufactured by Advantech Co., Ltd., product number: 300mm P-TEOS 10000A)
・ SiN substrate (300mm wafer, manufactured by Advantech Co., Ltd., product number: (CVD-) LP-SiN 2500A)
-Polishing equipment and polishing conditions-
Polishing device: FREX300E manufactured by Ebara Corporation
Polishing pad: Use one of the following ・Foam polyurethane pad H800-Type1 (Shore A hardness: 89.4 °) manufactured by Fujibo Holdings Co., Ltd.
・ Foamed polyurethane pad H800-CZM (Shore A hardness: 78.9°) manufactured by Fujibo Holdings Co., Ltd.
・Polyurethane foam pad X400-CZM manufactured by Fujibo Holdings Co., Ltd. (Shore A hardness: 76.3°)
Conditioner (dresser): Nylon brush (manufactured by 3M)
Polishing pressure: 2.0 psi (1 psi = 6894.76 Pa)
Polishing surface plate rotation speed: 80 rpm
Head rotation speed: 80rpm
Supply of polishing composition: Free-flowing Amount of supply of polishing composition: 200 mL/min Polishing time: 30 seconds.

[Rinse polishing process]
After polishing the surface of the TEOS substrate in the CMP process, the polished TEOS substrate was removed from the polishing surface plate (platen) as a polished object to be polished. Subsequently, in the same polishing apparatus, the polished TEOS substrate was mounted on another polishing platen (platen), and the surface treatment compositions A1 to A6 and B1 to B9 prepared above were used under the following conditions. , rinse-polishing treatment was performed on the polished TEOS substrate surface;
- Rinse Polishing Apparatus and Conditions for Rinse Polishing -
Polishing pressure: 1.0 psi
Surface plate rotation speed: 60 rpm
Head rotation speed: 60rpm
Supply of polishing composition: free flowing Surface treatment composition supply rate: 300 mL/min Polishing time: 60 seconds.

After the rinse-polishing treatment, the substrate surface was brush-cleaned with deionized water for 60 seconds to obtain a rinse-polished and polished TEOS substrate.

<Evaluation>
For each polished TEOS substrate after the rinse polishing step, the following items were measured and evaluated. Evaluation results are shown in Tables 2 to 6.

Table 2 shows the "each surface treatment for the polished TEOS substrate" obtained by polishing the TEOS substrate (object to be polished) using the polishing composition C1 and H800-Type 1 as the polishing pad in the polishing step. Evaluation results of compositions A1 to A6 and B1 to B9 (Examples 1 to 6 and Comparative Examples 1 to 9)” are shown.

Table 3 shows the "each surface treatment for the polished TEOS substrate" obtained by polishing the TEOS substrate (object to be polished) using the polishing composition C1 and H800-CZM as the polishing pad in the polishing step. Evaluation results of compositions A1 to A6 and B1 to B9 (Examples 7 to 12 and Comparative Examples 10 to 18)” are shown.

Table 4 shows the "each surface treatment for the polished TEOS substrate" obtained by polishing the TEOS substrate (object to be polished) using the polishing composition C1 and X400-CZM as the polishing pad in the polishing step. Evaluation results of compositions A1 to A6 and B1 to B9 (Examples 13 to 18 and Comparative Examples 19 to 27)” are shown.

Table 5 shows the "each surface treatment for the polished TEOS substrate" obtained by polishing the TEOS substrate (object to be polished) using the polishing composition C2 and H800-Type 1 as the polishing pad in the polishing step. Evaluation results of compositions A1 to A6 (Examples 19 to 24)” are shown.

Table 6 shows, in the polishing step, using the polishing composition C1 and using H800-Type 1 as the polishing pad to polish the SiN substrate (object to be polished). Evaluation results of compositions A1 to A5 (Reference Examples 1 to 5)” are shown. Table 6 also shows the evaluation results of the polished TEOS substrate under the same conditions. This reference example is to test whether the surface treatment composition of the present invention can exert the effect of the present invention also on a SiN substrate, and the polished polishing object contains silicon oxide and silicon nitride. In any case, the purpose is to test whether the surface treatment composition of the present invention is suitable for use.

[Evaluation of total number of residues]
As for the total number of residues, the number of residues on the polished TEOS substrate surface after rinsing treatment was evaluated using an optical inspection machine Surfscan (registered trademark) SP5 manufactured by KLA-Tencor Corporation. Specifically, the remaining portion excluding a portion having a width of 5 mm from the outer peripheral edge of one side of the polished TEOS substrate (a portion having a width of 0 mm to 5 mm when the outer peripheral edge is 0 mm) has a diameter of 50 μm. was counted. The smaller the number of residues, the better. The results are shown in Tables 2 to 6 below. Note that when the total number of residues exceeds 10000, the number cannot be detected, so Tables 2 to 6 indicate ">10000".

[Evaluation of Number of Abrasive Grain Residues and Number of Polyurethane Residues]
The number of abrasive grain residues and the number of polyurethane residues of the polished TEOS substrate after the rinse polishing treatment were measured by SEM observation using a Review SEM RS6000 manufactured by Hitachi High-Tech Corporation. First, by SEM observation, 100 samples of residues existing in the remaining portion excluding a portion having a width of 5 mm from the outer peripheral end portion of one side of the polished object were sampled. Next, from among the 100 sampled residues, the type of residue (abrasive grain or polyurethane) was determined by visual SEM observation, and the number of abrasive grains (CeO ₂ or SiO ₂ ) and polyurethane was confirmed. By doing so, the ratio (%) of abrasive grain residue and the ratio (%) of polyurethane residue in the residue were calculated. Then, the product of the total number of residues exceeding 50 μm in diameter (pieces) measured by the above evaluation of the total number of residues and the ratio (%) of the abrasive residue in the residue calculated by SEM observation was calculated. It was calculated as the number (pieces). In addition, the product of the total number of residues exceeding 50 μm in diameter (pieces) measured by the evaluation of the total number of residues described above and the ratio (%) of polyurethane residues in the residue calculated by SEM observation was calculated as the number of polyurethane residues (pieces). calculated as

In Tables 2 to 6, "number of abrasive grain residues" is the residue of inorganic oxide abrasive grains (CeO ₂ abrasive grain residue or SiO ₂ abrasive grain residue), and "polyurethane residue number" is the residue of the polishing pad. is. When the total number of residues exceeded 10,000, the number of abrasive grain residues and the percentage content of polyurethane residues in the residues could not be calculated. Since most of the residues are considered to be abrasive residues, in Tables 2 to 6, when the total number of residues exceeds 10000, the number of abrasive residues is indicated as ">10000", and the number of polyurethane residues is Indicate "-".

[Zeta potential measurement]
[Zeta potential measurement of inorganic oxide abrasive grains]
The zeta potential of the inorganic oxide abrasive grains is a value measured by Zetasizer Nano ZSP manufactured by Spectris Co., Ltd. (Malvern Division). The zeta potential of the _CeO2 abrasive grains during rinsing with the surface treatment composition, and the zeta potential of the anion-modified _SiO2 abrasive grains during rinsing with the surface treatment composition, respectively, were obtained from the following model experiments: The value measured by These values are shown in Tables 1 to 6 below.

(CeO ₂ abrasive)
A CeO ₂ particle dispersion (HC30 manufactured by Solvay, a 30% by mass aqueous dispersion of colloidal ceria having an average primary particle size of 30 nm and an average secondary particle size of 60 nm) was added to the surface treatment composition prepared above. , a measuring solution with a _CeO2 particle concentration of 0.02% by mass was prepared (the content of _CeO2 particles in the measuring solution is 0.02% by mass relative to the total mass of the measuring solution). The resulting measurement solution was filled in a dedicated measurement cell of the above device (Zetasizer Nano ZSP), and the zeta potential of the CeO ₂ abrasive grains was measured.

(anion-modified _SiO2 abrasive)
Anion-modified SiO ₂ particle dispersion (anion-modified colloidal silica (“Sulfonic acid-functionalized silica through quantitative oxidation of thiol groups”, Chem. Commun. 246-247 (2003), the method described in 19.5% by mass aqueous dispersion of sulfonic acid-modified colloidal silica, average primary particle size: 35 nm, average secondary particle size: 70 nm) prepared in ) to obtain an anion-modified _SiO2 particle concentration of 0.02 mass % measurement solution was prepared (the content of anion-modified _SiO2 particles in the measurement solution was 0.02% by weight relative to the total weight of the measurement solution). The obtained measurement solution was filled in the measurement cell of the above device (Zetasizer Nano ZSP) to measure the zeta potential of the anion-modified _SiO2 abrasive grains.

[Measurement of Zeta Potential of Polished TEOS Substrate, Polished SiN Substrate and Polyurethane]
The zeta potential of the polished TEOS substrate and the zeta potential of polyurethane are values measured by a solid state zeta potential measuring instrument SurPASS3 manufactured by Anton Paar Japan K.K. The zeta potential of the polished TEOS substrate surface during rinsing with the surface treatment composition, the zeta potential of the polished SiN substrate surface, and the zeta potential of the polyurethane during rinsing with the surface treatment composition are as follows. A value measured in a model experiment such as These values are shown in Table 1 below.

For the zeta potential of polyurethane, a polyurethane pad cut into 60 mm squares (foamed polyurethane pad H800-Type1 manufactured by Fujibo Holdings Co., Ltd.) was used as an object to be measured.

The zeta potential of the surface of the polished TEOS substrate was measured using a TEOS substrate (300 mm wafer, manufactured by Advantech, product number: 300 mm P-TEOS 10000A) cut into 60 mm squares. The zeta potential of the surface of the polished SiN substrate was measured using a SiN substrate (300 mm wafer, Advantech Co., Ltd., product number: (CVD-)LP-SiN 2500A) cut into 60 mm squares.

Each of these measurement objects was installed in a zeta potential meter. Next, the surface treatment compositions prepared above were passed through the measurement objects, and the zeta potentials of these measurement objects were measured.

As shown in Tables 2 to 4, in Examples 1 to 18, the TEOS substrate was polished with the polishing composition C1 (that is, the polishing composition using cerium oxide abrasive grains as abrasive grains), and then the surface was treated. It was found that rinsing the polished TEOS substrates with compositions A1 to A6 significantly reduced the residue (total number of residues) on the polished TEOS substrates. Further, as shown in Table 5, according to Examples 19 to 24, the TEOS substrate was polished with the polishing composition C2 (that is, the polishing composition using anion-modified colloidal silica abrasive grains as abrasive grains). However, it was found that rinsing the polished TEOS substrate using the surface treatment compositions A1 to A6 significantly reduced the residue (total number of residues) on the polished TEOS substrate.

In Table 6, it was confirmed that the surface treatment compositions A1 to A5 were effective in reducing the residue even on SiN substrates. Therefore, it was found from Reference Examples 1 to 5 that the surface treatment composition of the present invention can exhibit the effect of the present invention even on SiN substrates. From this, it was found that the surface treatment composition of the present invention can be suitably used even when the polished object contains silicon oxide and silicon nitride.

From this fact, when a polishing composition containing cerium oxide abrasive grains or anion-modified colloidal silica abrasive grains is used as abrasive grains to polish an object to be polished containing silicon oxide, the polished object to be polished has the surface of the present invention. It can be seen that the residues (abrasive grains, polishing pad) adhering to the polished object can be sufficiently removed by surface treatment with the treatment compositions A1 to A6. Although the above is the result of evaluating the surface treatment composition immediately after its production, it is preferable to contain an antifungal agent (preservative) when preserving or storing for a long period of time. Since the antifungal agent (preservative) has little or no effect on the above results, it is considered that a surface treatment composition containing an antifungal agent (antiseptic agent) will also produce the same results as above.

Claims (17)

A surface treatment method for reducing residue containing inorganic oxide abrasive grains on the surface of a polished object containing silicon oxide using a surface treatment composition,
The surface treatment composition comprises a zeta potential adjusting agent having an sp value of more than 9 and not more than 11 and having a negatively charged functional group, and a dispersion medium,
A surface treatment method, comprising controlling the zeta potential of the silicon oxide to be negative and the zeta potential of the inorganic oxide abrasive grains to −30 mV or less with the surface treatment composition. 2. The surface treatment method according to claim 1, wherein the inorganic oxide abrasive grains contain cerium oxide abrasive grains, and the surface treatment composition controls the zeta potential of the cerium oxide abrasive grains to −30 mV or less. 2. The surface treatment method according to claim 1, wherein said residue further comprises polyurethane, and further comprising controlling the zeta potential of said polyurethane to −30 mV or less with said surface treatment composition. 2. The surface treatment method according to claim 1, wherein said zeta potential adjusting agent is an anionic surfactant having a molecular weight of less than 1,000. The anionic surfactant has at least one functional group selected from the group consisting of a sulfonic acid (salt) group, a sulfate (salt) group, a phosphonic acid (salt) group, and a phosphate (salt) group. The surface treatment method according to claim 4. The surface treatment method according to claim 1, wherein the surface treatment composition further contains a pH adjuster. The surface treatment method according to claim 1, wherein the surface treatment composition has a pH value of 2 or more and less than 5. 2. The surface treatment method according to claim 1, which is a rinse polishing treatment method or a cleaning treatment method. The polished object to be polished is a polished semiconductor substrate,
a polishing step of obtaining a polished semiconductor substrate by polishing an unpolished semiconductor substrate containing silicon oxide using a polishing composition containing inorganic oxide abrasive grains;
a surface treatment step of reducing residue containing the inorganic oxide abrasive grains on the surface of the polished semiconductor substrate by the surface treatment method according to claim 1;
A method of manufacturing a semiconductor substrate, comprising: The inorganic oxide abrasive grains include cerium oxide abrasive grains,
10. The method of manufacturing a semiconductor substrate according to claim 9, comprising controlling the zeta potential of said cerium oxide abrasive grains to -30 mV or less by said surface treatment composition used in said surface treatment step. The polishing step includes using a polyurethane polishing pad,
The residue further contains the polyurethane,
10. The method of manufacturing a semiconductor substrate according to claim 9, further comprising controlling the zeta potential of said polyurethane to -30 mV or less with said surface treatment composition used in said surface treatment step. 12. The method of manufacturing a semiconductor substrate according to claim 11, wherein the polishing pad has a Shore A hardness of 40[deg.] or more and 100[deg.] or less. A surface treatment composition used to reduce residue containing inorganic oxide abrasive grains on the surface of a polished object containing silicon oxide, comprising:
A zeta potential adjusting agent having an sp value of more than 9 and not more than 11 and having a negatively charged functional group, and a dispersion medium,
A surface treatment composition having a function of controlling the zeta potential of the silicon oxide to be negative and controlling the zeta potential of the inorganic oxide abrasive grains to −30 mV or less. The surface treatment composition according to claim 13, wherein the inorganic oxide abrasive grains contain cerium oxide abrasive grains, and the surface treatment composition has a function of controlling the zeta potential of the cerium oxide abrasive grains to −30 mV or less. thing. 14. The surface treatment composition according to claim 13, wherein said residue further contains polyurethane, and said surface treatment composition further has a function of controlling the zeta potential of said polyurethane to -30 mV or less. 14. The surface treatment composition according to claim 13, which is a rinse polishing composition or a cleaning composition. A semiconductor substrate manufacturing system comprising an object to be polished containing silicon oxide, a polishing pad, a polishing composition containing inorganic oxide abrasive grains, and the surface treatment composition according to claim 13,
A system for manufacturing a semiconductor substrate, wherein the surface of the object to be polished after polishing with the polishing composition and the polishing pad is brought into contact with the surface treatment composition.