KR20230047001A - Polishing composition and polishing method using the same - Google Patents

Abstract

The objective of the present invention is to provide a polishing composition which increases the polishing rate of molybdenum (high Mo removal rate (RR)/Mo static etch rate (SER) ratio) and the ratio of the polishing rate of molybdenum to the polishing rate of silicon oxide (Mo:TEOS selective polishing rate) while reducing etching of molybdenum. More specifically, the present invention provides a polishing composition which comprises an abrasive, a molybdenum (Mo) polishing rate enhancer, an organic acid, an oxidizing agent, a corrosion inhibitor, and water combined in specific amounts and has advantageous properties such as a high Mo RR/Mo SER ratio and a high Mo:TEOS selective polishing rate, thereby providing a composition suitable for polishing molybdenum surfaces.

Description

Polishing composition and polishing method using the same {POLISHING COMPOSITION AND POLISHING METHOD USING THE SAME}

The present disclosure provides a polishing composition and a polishing method using the same.

CMP is a process of removing material from the surface of a substrate (such as a semiconductor wafer) and polishing (planarizing) the surface by combining a physical process such as grinding with a chemical process such as oxidation or chelation. In its most basic form, CMP requires application of a slurry to a substrate surface or a polishing pad that polishes the substrate. By this process, both removal of unnecessary material and planarization of the substrate surface are realized. It is not desirable for the removal or polishing process to be purely physical or purely chemical, but rather to include a synergistic combination of both.

CMP is used for a wide variety of objects. Examples include silicon dioxide (SiO ₂ ) in interlayer or buried dielectrics; metals such as aluminum (Al), copper (Cu), and tungsten (W) in wiring layers or plugs connected to such wiring layers; barrier metal layers such as tantalum (Ta), tantalum nitride (TaN), and titanium (Ti); polysilicon for use as trench capacitors; And molybdenum (Mo), which is used for a wide range of uses, is included.

Molybdenum has many industrial uses including connectors, photomasks and microelectronic devices such as the manufacture of semiconductor devices. In these applications, molybdenum is often used initially in excess. For this reason, in order to provide a substrate with appropriate surface properties, it is necessary to remove some of the molybdenum.

In a substrate containing such molybdenum, there is a new demand for selectively polishing molybdenum with respect to other materials (for example, silicon oxide using tetraethyl orthosilicate (TEOS) as a raw material) while polishing molybdenum at a high polishing rate. is happening

Therefore, polishing of semiconductors requires selective removal of molybdenum compared to other materials such as silicon oxide. However, current polishing compositions used for molybdenum have insufficient polishing rates. Due to these limitations, in the case of using CMP, the polishing process is lengthened and the throughput of the process is lowered. Also, it is disadvantageous for a layer of material other than the molybdenum layer (for example, a layer of silicon oxide under the molybdenum layer) to be polished. Therefore, it is necessary that the ratio of the removal rate of molybdenum to the removal rate of silicon oxide is high (ie, the selectivity ratio of the removal rate of molybdenum to silicon oxide is high). Therefore, polishing compositions currently used in CMP have problems such as improving the removal rate of molybdenum and improving the selectivity of the removal rate of molybdenum with respect to silicon oxide.

In view of the challenges surrounding the selective polishing of molybdenum-containing substrates, while reducing the etching of molybdenum and improving the molybdenum removal rate, the ratio of the removal rate of molybdenum to the removal rate of silicon oxide is high (ie, silicon oxide It is important to specify a polishing composition that has a high removal rate selectivity of molybdenum relative to the polishing composition. These and other challenges are addressed by the subject matter disclosed herein.

U.S. Patent No. 7,994,057 U.S. Patent No. 9,028,572 U.S. Patent No. 9,422,456

According to the object of the subject matter disclosed herein, which is embodied and broadly described herein, or the problem to be solved by the present invention, an object of the present invention is to promote the improvement of the polishing rate when using CMP, containing molybdenum. A composition for polishing a substrate such as a substrate is provided. Another object of the present invention is to provide a method for selectively removing materials such as molybdenum from a substrate.

Accordingly, the subject matter disclosed herein in one aspect relates to a polishing composition comprising an abrasive, a molybdenum removal rate improver, an organic acid, an oxidizing agent, a corrosion inhibitor and water. In some embodiments, the abrasive is cationically modified silica; The molybdenum removal rate improver is an iron salt; The oxidizing agent is a peroxide; corrosion inhibitors are positively charged amino acids; The pH of the polishing composition is about 2 to about 5.

In a further embodiment, the polishing composition has a molybdenum removal rate of at least about 200 Å/min and a TEOS removal rate of less than about 50 Å/min. In a further embodiment, the Mo:TEOS polishing rate selectivity of the polishing composition is at least about 4.5.

In another aspect, a subject matter described herein is a method of polishing a substrate, comprising: 1) preparing the polishing composition according to claim 1; 2) preparing a substrate comprising a molybdenum-containing layer; and 3) polishing the substrate with the polishing composition to provide a polished substrate.

The invention may be more readily understood by reference to the following detailed description of the invention and the examples contained therein.

Prior to the disclosure and description of the compounds, compositions, articles, systems, devices and/or methods of the present invention, they are not limited to specific synthesis methods unless otherwise specified, or limited to specific components unless otherwise specified. You have to understand what not. This is because such synthesis methods and components are naturally subject to change. It should be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, exemplary methods and materials are described herein.

Described herein is a polishing composition comprising an abrasive, a molybdenum removal rate improver, an organic acid, an oxidizing agent, a corrosion inhibitor and water. These polishing compositions are intended to polish substrates. The present invention (a1) has a high removal rate of molybdenum while reducing the etching of molybdenum; and (a2) a high ratio of the removal rate of molybdenum to the removal rate of silicon oxide (hereinafter referred to as “a high selectivity ratio of the removal rate of molybdenum to silicon oxide”). do.

Hereinafter, "the molybdenum removal rate is high while reducing molybdenum etching" may be referred to as "the Mo RR/Mo SER ratio is high". Mo RR means molybdenum removal rate, and Mo SER means molybdenum static etch rate. In addition, a high ratio of the removal rate of molybdenum to the removal rate of silicon oxide means that the selection ratio of the removal rate of molybdenum to silicon oxide is high. There are cases where it is referred to as "the rate selection ratio is high".

(a1) having a high Mo RR/Mo SER ratio; and (a2) that the Mo:TEOS removal rate selectivity is high, both effects are preferably excellent. According to one embodiment, (a1) the effect that the Mo RR/Mo SER ratio is high is far superior to the effect that (a2) the Mo:TEOS removal rate selectivity is high. Further, according to another embodiment, (a2) the effect of a high Mo:TEOS removal rate selectivity is far superior to the effect of (a1) a high Mo RR/Mo SER ratio.

In addition, another object of the present invention is, 1) a low molybdenum static etch rate; 2) high molybdenum removal rate; 3) low TEOS removal rate; 4) high composition stability; and 5) a high Mo:TEOS polishing rate selectivity ratio.

Here, the "static etching rate" is to calculate the rate at which the test piece is etched when the test piece is immersed in the etching solution. When the static etching rate is high, the surface of the object is chemically eroded and the film thickness becomes thin. In that case, flatness of the surface is generally not guaranteed. In addition, control of the film thickness after polishing by polishing becomes difficult. Therefore, a lower etching rate is preferred for the polishing composition.

The effect of the polishing composition of the present invention is that the removal rate of molybdenum is high and the selection ratio of the removal rate of molybdenum to TEOS is high. This effect can be evaluated by the fact that the static etching rate of molybdenum is low and the ratio of the removal rate of molybdenum to the static etching rate of molybdenum is high.

The static etching rate of molybdenum by the polishing composition of the present invention is preferably 100 Å/min or less, more preferably 50 Å/min or less, still more preferably 20 Å/min or less, and particularly preferably less than 20 Å/min. The lower limit of the static etching rate of molybdenum is not particularly limited, but in practice it is 0.1 Å/min or more.

The molybdenum removal rate of the polishing composition of the present invention is preferably 150 Å/min or more, more preferably 200 Å/min or more, and still more preferably 210 Å/min or more. The upper limit of the removal rate of molybdenum is not particularly limited, but in practice, it is 500 Å/min or less.

The polishing rate of TEOS by the polishing composition of the present invention is preferably 55 Å/min or less, more preferably 50 Å/min or less, and still more preferably 48 Å/min or less. In one embodiment, the polishing rate of TEOS with the polishing composition is less than 50 A/min. Further, in one embodiment, the polishing rate of TEOS by the polishing composition is less than 40 Å/min. The lower limit of the removal rate of TEOS is not particularly limited, but in practice, it is 5 Å/min or more.

The Mo RR/Mo SER ratio of the polishing composition of the present invention is preferably 20 or more, more preferably 23 or more, and still more preferably 25 or more. The upper limit of the Mo RR/Mo SER ratio is not particularly limited, but in practice, it is 50 or less.

The Mo:TEOS polishing rate selectivity of the polishing composition of the present invention is preferably 4 or more, more preferably 4.5 or more, still more preferably 6 or more. The upper limit of the Mo:TEOS polishing rate selectivity ratio is not particularly limited, but in practice it is 30 or less.

The molybdenum static etch rate, molybdenum removal rate, TEOS removal rate, composition stability, and Mo:TEOS removal rate selectivity of the polishing composition described herein are important properties. Compositions exhibiting these important properties can be obtained by using certain components in the required amounts. For example, in one embodiment, it has been found that a polishing composition comprising an abrasive, a molybdenum removal rate enhancer, an organic acid, an oxidizing agent, a corrosion inhibitor and water results in a high Mo:TEOS removal rate selectivity ratio, and a high Mo It is necessary that the concentration of each component of the polishing composition be present in a specific amount in order to result in a polishing rate and a low TEOS polishing rate. For example, if too much corrosion inhibitor is included in the polishing composition, detrimental effects (such as an unacceptably low Mo removal rate) may be observed. These and other effects of ingredients and concentrations of ingredients are discussed further herein.

The polishing composition described in this specification has applications such as CMP of molybdenum-containing substrates, but is not limited thereto.

A. Definition

Listed below are definitions of various terms used to describe the present invention. These definitions apply to terms used throughout this specification, either individually or as part of a larger group, unless specifically limited in a particular case.

As used in this specification and appended claims, the singular forms "a", "an" and "the" shall include plural unless the context clearly indicates otherwise. Thus, for example, reference to "an abrasive" or "a pH adjuster" includes mixtures of two or more such abrasives or pH adjusters.

A range can be expressed herein as "about" a certain value, and/or "about" another particular value. Where such ranges are expressed, other aspects include from any particular value and/or to any other particular value. Similarly, by using the antecedent “about,” it will be understood that when values are expressed as approximations, different aspects are formed by particular values. It will also be appreciated that the endpoints of each range are significant in relation to, and independently of, the other endpoints. It will also be understood that there are a number of values disclosed herein, and that each value is disclosed herein as “about” its specific value, in addition to the value itself. For example, when the value "10" is disclosed, "about 10" is also disclosed. It will also be appreciated that each structural unit between two specific structural units is also disclosed. For example, when 10 and 15 are disclosed, 11, 12, 13 and 14 are also disclosed.

In the claims of the specification and conclusions, references to parts by weight of a particular element or component in a composition indicate a weight relationship between that element or component and any other element or component in the composition or article for which the parts by weight are expressed. . Therefore, in a compound containing 2 parts by weight of component "X" and 5 parts by weight of component "Y", "X and Y" are present in a weight ratio of 2:5, regardless of whether other components are contained in the composition. , is present in the corresponding proportion.

Weight percentages (wt%) of components are based on the total weight of the vehicle or composition in which the component is incorporated, unless otherwise specified.

When used in this specification, the terms "optional" and "optionally" mean that the event or situation described thereafter may or may not occur, and the description Cases in which the event or situation occurs and cases in which it does not occur are included.

B. Polishing composition

The basic mechanism of CMP is to soften the surface layer by chemical reaction and then remove the softened layer by mechanical force using abrasive particles. However, the role of CMP is not only material removal, but also planarization, surface smoothing, uniformity control, defect reduction, and others. Therefore, the improvement of semiconductor yield is affected by CMP processing. Scratches on the surface that can be caused by CMP are very detrimental defects in semiconductor manufacturing. Therefore, in order to achieve proper CMP performance without scratching the surface, it is very important to develop a polishing composition. CMP requirements include a flattened surface with a flatness of less than 15 nm, a surface without roughness with a surface roughness of less than 1 nm, a defect-free surface with 0 counts of scratches and pits per wafer, no contamination, and high productivity. and those that are planarized in a state where the removal rate of the material to be removed is high.

One important performance indicator for polishing compositions for use on molybdenum (Mo) and TEOS containing substrates is a high Mo:TEOS removal rate selectivity, whereby TEOS removal is minimal. A polishing composition with a high Mo:TEOS selectivity ratio is ideally formulated at a pH of 2 to 5. These and other aspects are discussed again herein.

In light of the complexities surrounding the various mechanisms of Mo and TEOS removal rates, it is necessary to characterize compositions that enable high Mo removal rates while simultaneously enabling low TEOS removal rates, and thus result in high Mo:TEOS removal rate selectivity ratios. It is important.

Accordingly, important aspects of the polishing composition described herein include: 1) a high Mo removal rate (RR); 2) low Mo static etch rate (SER); 3) high Mo RR/Mo SER ratio; 4) low TEOS RR; 5) high Mo:TEOS removal rate selectivity; and 6) major pH. As described herein, specific combinations of components in specific amounts are key to obtaining their desired properties.

1. Abrasive

The polishing composition described herein contains an abrasive. The abrasive is usually a metal oxide abrasive preferably selected from the group consisting of silica, alumina, titania, zirconia, germania, ceria, and mixtures thereof. In some embodiments, the abrasive is silica. In a further embodiment, the abrasive is colloidal silica.

In some embodiments, the abrasive is surface modified. For example, the surface-modified abrasive may be cationic modified silica. In one embodiment, the cationically modified silica can be a silica that has been surface modified by treatment with an aminosilane to produce a silica with a positive zeta potential. In another embodiment, the surface of the silica particles is treated with a bis(trimethoxysilylpropyl)amine, for example an aminosilane such as SILQEST Al 170 (Crompton OSi Specialties), or a similar reactive aminosilane. As a result of these treatments, an amino group is covalently bonded to the surface of the cation-modified silica.

Cationically modified silica particles having a permanent positive charge in the polishing composition can be obtained by treating the particles with at least one aminosilane compound, as disclosed in, for example, U.S. Patent No. 7,994,057 and U.S. Patent No. 9,028,572. Alternatively, cation-modified silica particles having a permanent positive charge in the polishing composition can be obtained by embedding a chemical species such as an aminosilane compound into colloidal silica particles, as disclosed in U.S. Patent No. 9,422,456.

In addition, similarly to cation-modified silica, a commercially available aqueous dispersion can be used. Examples of such commercially available products include Snowtex AK, Snowtex AK-L (all trade names of Nissan Chemical Industries, Ltd.), Cataloid SN (trade names of Nikki Shokubai Kasei Co., Ltd.), and Quartron PL-3-C (Fuso A trade name manufactured by Gagaku Kogyo Co., Ltd.) is included.

In one embodiment, the abrasive is colloidal silica. In a further embodiment, the abrasive has a positive zeta potential. In yet another embodiment, the abrasive is silica which has a positive zeta potential when in the polishing composition. A positive zeta potential may range from about +5 mV to about +60 mV, from about +10 mV to about +55 mV, or from about +20 mV to about +50 mV. Additionally, the positive zeta potential may range from about +5 mV to about +60 mV, from about +10 mV to about +50 mV, or from about +20 mV to about +40 mV. Also, in some embodiments, the positive zeta potential is about +5 mV, about +10 mV, about +15 mV, about +20 mV, about +25 mV, about +30 mV, about +35 mV, about +40 mV, about +45 mV, about +50 mV, about +55 mV, or about +60 mV.

The abrasive can have any suitable particle size. For example, the abrasive can have an average secondary particle diameter of about 10 nm or greater, about 25 nm or greater, about 40 nm or greater, about 50 nm or greater, or about 60 nm or greater. Alternatively or additionally, the abrasive may have an average secondary particle size of less than about 1,000 nm, less than about 500 nm, less than about 200 nm, less than about 120 nm, less than about 100 nm, less than about 90 nm, or less than about 80 nm. there is. For example, in some embodiments, the abrasive can have an average secondary particle size ranging from about 40 nm to about 120 nm, from about 50 nm to about 100 nm, or from about 60 nm to about 80 nm. In some embodiments, the average secondary particle size is about 10 nm, about 15 nm, about 20 nm, about 25 nm, about 30 nm, about 35 nm, about 40 nm, about 45 nm, about 50 nm, about 65 nm, about 70 nm, about 75 nm, or about 100 nm. A particle size distribution measuring device (Horiba particle size distribution device) can measure the average particle size of an abrasive.

The abrasive can have any suitable surface area. For example, the abrasive can have an average surface area of about 50 m 2 /g or greater, about 60 m 2 /g or greater, or about 70 m 2 /g or greater. Alternatively or additionally, the abrasive may have an average surface area of about 120 m 2 /g or less, about 110 m 2 /g or less, about 100 m 2 /g or less, or about 90 m 2 /g or less. In some embodiments, the abrasive has an average surface area of about 55 m/g, about 65 m/g, about 75 m/g, about 80 m/g, about 85 m/g, or about 90 m/g. can have

In some embodiments, the amount of abrasive affects the properties of polishing compositions such as Mo RR, Mo SER and TEOS RR. The concentration of the polishing composition is about 0.01% by weight or more, about 0.05% by weight or more, about 0.1% by weight or more, about 0.2% by weight or more, about 0.25% by weight or more, about 0.5% by weight or more, about 0.75% by weight or more with respect to the total composition. or more, about 1% by weight or more, about 3% by weight or more, or about 5% by weight or more. Alternatively or additionally, the amount of abrasive in the polishing composition is about 5% or less, about 3% or less, about 1% or less, about 0.75% or less, about 0.5% or less, about 0.25% or less, about 0.1% or less. wt% or less, about 0.05 wt% or less, about 0.01 wt% or less, or about 0.05 wt% or less. In some embodiments, the amount of abrasive in the polishing composition is about 0.01% to about 5%, about 0.05% to about 2.5%, about 0.1% to about 1.5%, or about 0.5%. to about 1% by weight. In some embodiments, the amount of abrasive is about 0.1%, about 0.25%, about 0.5%, about 0.75%, about 1%, about 1.35%, about 1.5%, about 2%. , about 3%, about 4%, or about 5%. In one embodiment, the amount of abrasive is from about 1.0% to about 1.5% by weight. In one embodiment, the amount of abrasive is about 1.35% by weight of the total composition. In another embodiment, the amount of abrasive is about 0.75% by weight of the total composition.

The abrasive may be of any reasonable size, but the size of the abrasive affects the smoothness of the resulting finish. Precision abrasive work materials such as optical components, plastics, metals, jewelry, and semiconductor components usually require the use of smaller abrasives. For example, a composition for use involving precision abrasive requires a suspension of an abrasive having a smaller average particle size.

The abrasive is colloidally stable when suspended in the composition disclosed herein. The term colloid refers to a suspension of abrasive particles in a liquid carrier. Colloidal stability refers to the retention of a suspension over time. In some embodiments, the polishing composition is stable at 50°C for at least 1, 2, 3, 4, 5, 6, or 7 days. In some embodiments, the suspension is stable at 50° C. for at least 1 week, at least 2 weeks, at least 3 weeks, or at least 4 weeks.

In the context of the present invention, the polishing composition measures the particle concentration ([B], g/mL unit) in the lower 50 mL of the measuring cylinder when silica is placed in a 100 mL measuring cylinder and left without stirring for 2 hours, The value obtained by dividing the difference in particle concentration ([T], in g/mL units) in the upper 50 mL of the measuring cylinder by the total particle concentration ([C], in g/mL units) in the polishing composition is 0.5 or less. (ie, when ([B]-[T])/[C] is 0.5 or less), it is considered colloidally stable. The value of ([B]-[T])/[C] is preferably 0.3 or less, preferably 0.1 or less, more preferably 0.05 or less, still more preferably 0.04 or less, and most preferably It is less than 0.03.

In one embodiment, the abrasive is cationically modified silica. In some embodiments, the abrasive substantially comprises cationically modified silica. As used herein, “substantially” means that 95% by weight or more, preferably 98% by weight or more, and more preferably 99% by weight or more of the particles constituting the abrasive are cation-modified silica, which is 100% by weight of is cation-modified silica.

2. Molybdenum polishing rate improver

In one aspect, the polishing composition may contain one or more molybdenum (Mo) removal rate improvers. The removal rate improver is an iron salt, and removal of Mo is promoted when combined with an oxidizing agent such as hydrogen peroxide. Without being bound by theory, it is believed that this removal rate improvement proceeds through the Fenton reaction.

The iron salt used in the polishing composition is a salt of divalent iron, a salt of trivalent iron, a salt of high valent iron, zero-valent iron, Fe ₄ O ₃ , iron(III) oxide, iron(III) hydroxide, iron(II) oxide. can Non-limiting examples of ferrous salts include divalent iron (II) sulfate (FeSO ₄ ), iron (III) sulfate (Fe ₂ (SO ₄ ) ₃ ) and iron (III) nitrate (Fe(NO ₃ ) ₃ ). and salts of trivalent iron. In one embodiment, the molybdenum removal rate improver is iron(III) nitrate (Fe(NO ₃ ) ₃ ).

In some embodiments, the amount of iron salt affects the properties of polishing compositions such as Mo RR, Mo SER and TEOS RR. In some embodiments, the amount of iron salt present in the polishing composition is about 0.00001% to about 0.001% by weight, about 0.00005% to about 0.00075% by weight, based on the total amount of the polishing composition being 100% by weight. from about 0.0001% to about 0.0007%, from about 0.0002% to 0.0006%, or from about 0.0002% to about 0.0004%. In some embodiments, the iron salt is present in the polishing composition at greater than about 0.0001%, greater than about 0.00005%, greater than about 0.0001%, greater than about 0.0003%, or greater than about 0.0005% by weight. Alternatively or additionally, the amount of iron salt in the polishing composition may be about 0.001 wt% or less, about 0.0007 wt% or less, about 0.0005 wt% or less, about 0.0003 wt% or less, or about 0.00001 wt% or less. In some embodiments, the amount of iron salt is about 0.00001%, about 0.00005%, about 0.0001%, about 0.0002%, about 0.0003%, about 0.0004%, about 0.0005%, about 0.0006%. , about 0.0007% by weight, or about 0.001% by weight.

3. Oxidizer

Since the molybdenum removal rate improver is accompanied by an oxidizing agent, the Fenton reaction is promoted. The oxidizing agent used in the polishing composition of the present invention is a peroxide. Non-limiting examples of oxidizing agents include periodic acid, hydrogen peroxide, potassium iodate, potassium permanganate, persulfates (e.g., ammonium persulfate and potassium dipersulfate), periodates (e.g., periodic acid potassium acid), ammonium molybdate, ferric nitrate, nitric acid, potassium nitrate, and mixtures thereof. In one embodiment, the oxidizing agent is hydrogen peroxide.

In some embodiments, the amount of oxidizing agent affects the properties of polishing compositions such as Mo RR, Mo SER and TEOS RR. As discussed herein, oxidizing agents also affect the corrosion of Mo. The amount of oxidizing agent can range from about 0.1% to about 10%, about 0.25% to about 7.5%, about 0.5% to about 5%, or about 1% to about 2.5%. In one embodiment, the oxidizing agent is from about 0.1% to about 2.5% by weight. In some embodiments, the oxidizer is present in an amount of about 0.1% or greater, about 0.25% or greater, about 0.5% or greater, about 1% or greater, about 1.5% or greater, or about 3% or greater. In some embodiments, the oxidizer is present in an amount of 5% or less, about 3.5% or less, about 2% or less, about 1.5% or less, or about 1.0% or less. In some embodiments, the oxidizing agent is present in an amount of about 0.5%, about 1.0%, about 1.5%, about 3%, or about 5%.

The percentage of oxidizing agent is determined relative to the composition as a whole. Also, the percentage of oxidizing agent is measured as a point of use (POU) composition. As used herein, the term "point of use" refers to a composition prepared and used in the vicinity of a planarization device that supplies a planarization fluid to an individual planarization device for use in a CMP process.

4. Organic acids

In some embodiments of polishing compositions comprising an iron salt and an oxidizing agent, decomposition of the oxidizing agent has been observed. By adding an organic acid to the polishing composition, the oxidizing agent is effectively stabilized and decomposition of the oxidizing agent is reduced.

As used herein, the term "organic acid" refers to low molecular weight carboxylic acids that may have two or more carboxylic acid moieties. Therefore, "organic acid" includes any compound of the R-COOH type in which R- is an organic group, as well as dibasic and polybasic acids. Organic acids can be used in conjugated form, for example, carboxylic acid salts can be used instead of carboxylic acids. For purposes herein, the term "organic acid" also refers to the conjugated base of an organic acid. For example, the term "malonic acid" includes neutral malonic acid and its conjugated bases. Organic acids may be used alone or in combination.

When used as an organic acid, the organic group may be an alkyl, aryl, heteroaryl, or the like.

As used herein, the term "alkyl" refers to straight or branched chain hydrocarbons containing from 1 to 10 carbon atoms. Representative examples of alkyl include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, 3-methylhexyl, 2,2-dimethylpentyl, 2,3-dimethylpentyl, n-heptyl, n-octyl, n-nonyl, n-decyl and the like are included, but are not limited thereto. These alkyl groups may be substituted with other groups.

As used herein, the term "aryl" refers to a monocyclic, bicyclic or tricyclic aromatic ring system of hydrocarbons. When used in this specification, bicyclic and tricyclic aromatic ring systems are collectively referred to as "polycyclic" in some cases. An aryl group may be optionally substituted with one or more substituents. Examples of aryl groups include phenyl, naphthyl, anthracenyl, fluorenyl, indenyl, azulenyl, and the like.

As used herein, the term "heteroaryl" is a 5- or 6-membered monovalent aromatic group of 5 to 20 atoms containing one or a plurality of heteroatoms independently selected from nitrogen, oxygen, and sulfur. Refers to a group containing a condensed ring system (at least one of which is aromatic). Examples of heteroaryl groups include pyridinyl (including, for example, 2-hydroxypyridinyl), imidazolyl, imidazopyridinyl, pyrimidinyl (including, for example, 4-hydroxypyrimidinyl). ), pyrazolyl, triazolyl (including for example 3-amino-1,2,4-triazole or 3-mercapto-1,2,4-triazole), pyrazinyl (including (including aminopyrazine), tetrazolyl, furyl, thienyl, isoxazolyl, thiazolyl, oxadiazolyl, oxazolyl, isothiazolyl, pyrrolyl, quinolinyl, isoquinolinyl, tetrahydroiso quinolinyl, indolyl, benzimidazolyl, benzofuranil, sinnolinyl, indazolyl, indolizinyl, phthalazinyl, pyridazinyl, triazinyl, isoindolyl, pteridinyl, purinyl, thia diazolyl, furazanil, benzoprazanil, benzothiophenyl, benzothiazolyl, benzooxazolyl, quinazolinyl, quinoxalinyl, naphthyridinyl, oxazole-2(3H)-oneyl and propyridinyl. Thus, heteroaryl groups, in some embodiments, are monocyclic or bicyclic. Heteroaryl groups are optionally substituted.

As used herein, the term "substituted" refers to a moiety (such as an alkyl group) bonded to one or more separate organic groups. In some embodiments, the substituted moiety includes 1, 2, 3, 4 or 5 separate substituents or groups. Suitable organic substituents include, but are not limited to, hydroxyl, amino, monosubstituted amino, disubstituted amino, mercapto, alkylthiol, alkoxy, substituted alkoxy or haloalkoxy groups. When the substituted moiety is bonded to two or more substituents, the two or more substituents may be the same or different.

Non-limiting examples of organic acids include formic acid, acetic acid, chloroacetic acid, propionic acid, butanoic acid, valeric acid, 2-methylbutyric acid, N-hexanoic acid, 3,3-dimethylbutanoic acid, 2-ethylbutanoic acid, 4-methylphene Carbonic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, blood Melic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citrates, citric acid, lactic acid, diglycolic acid, 2-francarboxylic acid, 3-francarboxylic acid, 2-tetrahydrofrancarboxylic acid, methoxyacetic acid, methyl Toxyphenylacetic acid and phenoxyacetic acid are included. In some embodiments, the organic acid is malonic acid.

The organic acid may be present in a range of about 0.001% to about 0.1%, about 0.005% to about 0.05%, or about 0.01% to about 0.025% by weight. In some embodiments, the organic acid is present in an amount of at least about 0.001%, at least about 0.005%, at least about 0.01%, at least about 0.05%, or at least about 0.01%. In some embodiments, the organic acid is present in an amount of less than about 0.1%, less than about 0.05%, less than about 0.01%, or less than about 0.005%. In some embodiments, the organic acid is about 0.001%, about 0.005%, about 0.01%, about 0.012%, about 0.015%, about 0.02%, about 0.025%, or about 0.05%. is present in the amount of

5. Corrosion Inhibitors

The polishing composition described herein contains a corrosion inhibitor. In some embodiments, the corrosion inhibitor is an amino acid. As used herein, an amino acid is an organic compound containing amino (-NH ₂ ) and carboxyl (-COOH) functional groups, along with side chains (R groups) specific to each amino acid. A general, non-limiting structure of amino acids is shown below.

Amino acids are not limited to the general structure described above, but include amino acids including, but not limited to, other amino acids as shown below.

In some embodiments, the corrosion inhibitor is a positively charged amino acid. The term "charged amino acid" as used herein refers to an amino acid residue having a charged side chain at a pH relevant to the polishing composition disclosed herein. The term "charged amino acid" refers to the positively charged side chains present in arginine (Arg, R), histidine (His, I) and lysine (Lys, K), or aspartic acid (Asp, D) and glutamic acid (Glu, E). It may refer to an amino acid having any of the negatively charged side chains. Accordingly, the term "positively charged amino acid" refers to amino acids such as arginine (Arg, R), histidine (His, I) and lysine (Lys, K).

As used herein, the term "neutral amino acid residue" refers to any other amino acid that does not have a charged side chain at the relevant pH. Neutral amino acids include, but are not limited to, serine (Ser, S), threonine (Thr, T), asparagine (Asn, N), glutamine (Glu, Q), cysteine (Cys, C), glycine (Gly, G), proline (Pro, P), alanine (Ala, A), valine (Val, V), isoleucine (Ile, I), leucine (Leu, L), methionine (Met, M), phenylalanine (Phe, F), tyrosine ( Tyr, Y) and tryptophan (Trp, T).

In some embodiments, the corrosion inhibitor is a positively charged amino acid. In a further embodiment, the amino acid is selected from the group consisting of arginine, histidine and lysine.

Amino acids may be present in the polishing composition. In some embodiments, the amount of amino acids in the polishing composition ranges from about 0.01% to about 0.5%, about 0.05% to about 0.25%, or about 0.075% to about 0.15% by weight. In one embodiment, the amount of amino acid is from about 0.01% to about 0.15% by weight. In some embodiments, the amino acid is present in an amount of about 0.01% or greater, about 0.05% or greater, about 0.1% or greater, or about 0.2% or greater. Alternatively or additionally, the amount of amino acids present in the polishing composition may be about 0.5% by weight or less, about 0.25% by weight or less, about 0.1% by weight or less, or about 0.05% by weight or less. In some embodiments, the amount of amino acid is present in an amount of about 0.01%, about 0.05%, about 0.075%, about 0.1%, or about 0.2%.

6. pH Adjuster

The polishing composition described herein may also contain a pH adjuster. The pH adjuster is not particularly limited. However, the pH of the polishing composition directly affects the effectiveness of the polishing composition.

In some embodiments, the pH adjusting agent may be acidic in nature. Therefore, the pH adjusting agent is preferably an acid. The selection of the acid is not particularly limited as long as the strength of the acid is sufficient to lower the pH of the polishing composition of the present invention. For example, but not limited to, such acids include hydrochloric acid, sulfuric acid, nitric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, and phosphoric acid. In one embodiment, the pH adjusting agent is nitric acid.

In some embodiments, the pH of the polishing composition is adjusted to a range of about 2.0 to about 5.0, about 2.25 to about 4.0, or about 2.5 to about 3.0. In some embodiments, the pH is less than about 5.0, less than about 4.5, less than about 4.0, less than about 3.5, or less than about 3.0. In some embodiments, the pH is greater than about 2.0, greater than about 2.5, greater than about 3.5, greater than about 4.0 or greater than about 4.5. In some embodiments, the pH is about 2.0, 2.25, 2.5, 2.70, 2.75, 3.0, 3.25, 3.5, 3.75, 4.0, 4.25, 4.5, 4.75, or 5.0. In one embodiment, the pH is about 2.7. In one embodiment, the polishing composition has a pH of about 2 to about 4.

A pH adjusting agent, regardless of pH, can be present in a particular concentration range. For example, in some embodiments, the amount of pH adjusting agent ranges from about 0.01% to about 1%, about 0.02% to about 0.5%, or about 0.03% to about 0.1% by weight. In one embodiment, the amount of pH adjusting agent is from about 0.01% to about 0.1% by weight. In some embodiments, the amount of pH adjusting agent is at least about 0.01%, at least about 0.02%, at least about 0.03%, at least about 0.04%, at least about 0.05%, at least about 0.06%, or at least It is present in an amount of about 0.07% by weight. In some embodiments, the pH adjusting agent is present in an amount of less than about 1%, less than about 0.5%, less than about 0.1%, or less than about 0.05%. In some embodiments, the pH adjusting agent is about 0.01%, about 0.02%, about 0.03%, about 0.04%, about 0.05%, about 0.06%, about 0.07%, about 0.08%. , about 0.09%, about 0.1%, about 0.2%, about 0.3%, about 0.4%, or about 0.44%.

While not wishing to be bound by theory, it is believed that the pH of the composition affects performance for a variety of other reasons, such as effects on the Fenton reaction. For example, at low pH, complexation of Fe ²⁺ may occur and the amount of reactive species may decrease. A low pH also causes removal of hydroxyl radicals (ie, OH) by excess H ⁺ , and as a result, the reaction rate may be lowered. In contrast, at high pH, the concentration of Fe ³⁺ species in the solution is lowered due to precipitation of iron salts such as Fe(OH) ₃ , and the reaction may be slowed down. Also, the solubility of iron species is directly affected by the pH of the solution. The solubility of Fe ³⁺ is about 1/100 of that of Fe ²⁺ at a pH close to neutral. Under high pH conditions, the stability of H ₂ O ₂ is also affected, resulting in self-decomposition of H ₂ O ₂ .

Accordingly, the polishing compositions described herein have specific properties exemplified by Mo removal rate, Mo static etch rate, or TEOS removal rate performance.

For example, the polishing composition described herein has a Mo removal rate of at least about 100 Å/min, at least about 150 Å/min, at least about 180 Å/min, at least about 200 Å/min, at least about 250 Å/min, or at least about 300 Å/min. /min, at least about 400 Å/min, or at least about 500 Å/min. In some embodiments, the material removal rate ranges from about 100 Å/min to about 500 Å/min, from about 150 Å/min to about 300 Å/min, or from about 180 Å/min to about 250 Å/min. In some embodiments, the material removal rate is about 100 Å/min, about 150 Å/min, about 180 Å/min, about 200 Å/min, about 250 Å/min, or about 300 Å/min.

The molybdenum (Mo) static etch rate of the polishing composition described herein is less than about 100, less than about 75, less than about 50, less than about 25, less than about 20, less than about 15, less than about 10, less than about 5, or may be less than about 1. In some embodiments, the static etch rate is about 5, about 10, about 15, or about 20.

The TEOS polishing rate of the polishing composition described herein is about 100 Å/min, 90 Å/min, 80 Å/min, 70 Å/min, 60 Å/min, 50 Å/min, 40 Å/min, 30 Å/min, 20 Å/min, 10 Å/min, or less than 5 Å/min. In some embodiments, the polishing composition described herein has a TEOS polishing rate of about 5 Å/min, about 10 Å/min, about 20 Å/min, about 30 Å/min, about 40 Å/min, about 50 Å/min. , about 60 Å/min, about 70 Å/min or about 80 Å/min.

The polishing composition described herein has a ratio of Mo removal rate to Mo static etch rate of at least about 5, at least about 10, at least about 20, at least about 25, at least about 30, at least about 35, at least about 40, or at least about 50. In some embodiments, the ratio of Mo removal rate to Mo static etch rate is about 5, about 10, about 15, about 20, about 25, about 30, about 35, or about 40.

The polishing composition described herein has a ratio of Mo removal rate to TEOS removal rate of at least about 2, at least about 3, at least about 5, at least about 10, at least about 15, at least about 20, at least about 25, or It may be at least about 30. In some embodiments, the ratio of Mo removal rate to TEOS removal rate is about 2, about 3, about 5, about 10, about 15, about 20, or about 25.

The polishing composition according to claim 1, wherein the Mo:TEOS polishing rate selectivity of the polishing composition is at least about 5.

7. Water

In one embodiment, the polishing composition disclosed herein contains a carrier, medium, or vehicle. In one embodiment, the carrier, medium, or vehicle is water. Ion-exchanged water (deionized water), pure water, ultrapure water, distilled water and the like can be used as water. In order to reduce the amount of unnecessary components present in the water, the purity of the water may be increased by removal of impurity ions by an ion exchange resin, removal of contaminants by a filter, and/or distillation.

In some embodiments, the water is relatively free of impurities. In some embodiments, the water is about 10% w/w, about 9% w/w, about 8% w/w, about 7% w/w, about 6% w/w, based on the total weight of water. w, about 5% w/w, about 4% w/w, about 3% w/w, about 2% w/w, about 1% w/w, about 0.9% w/w, about 0.8% w/w , less than about 0.7% w/w, about 0.6% w/w, about 0.5% w/w, about 0.4% w/w, about 0.3% w/w, or less than about 0.1% w/w. .

8. Additional Ingredients

In one embodiment, the polishing composition disclosed herein may contain additional components such as chelating agents, biocides, surfactants, or co-solvents. Additionally or alternatively, the compositions disclosed herein may contain other additives, as will be understood by those skilled in the art.

In one embodiment, the additional component may include a chelating agent. The term chelating agent is intended to mean any substance that chelates a metal, such as copper, in the presence of an aqueous solution. Non-limiting examples of chelating agents include inorganic acids, organic acids, amines, and amino acids such as glycine and alanine, citric acid, maleic acid, oxalic acid, malonic acid, phthalic acid, succinic acid, nitrilotriacetic acid, iminodiacetic acid, ethylenediamine, and ethylenediamine. Acetic Acid (EDTA), Diethylenetriaminepentaacetic acid (DTPA), Triethylenetetraminehexaacetic acid (TTHA), Hydroxyethylidenediphosphonic acid (HEDP), Nitrilotrismethylphosphonic acid (NTMP), Phosphonobutanetricar boxylic acids (PBTC) and ethylenediaminetetramethylenephosphonic acid (EDTMP).

In one embodiment, the additional ingredient may be a biocide. Non-limiting examples of biocides include hydrogen peroxide, quaternary ammonium compounds and chlorine compounds. More specific examples of the quaternary ammonium compound include methylisothiazolinone, tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, alkylbenzyldimethylammonium chloride and alkyl having from 1 to about 20 carbon atoms in the alkyl chain. benzyldimethylammonium hydroxide, but is not limited thereto. More specific examples of chlorine compounds include, but are not limited to, sodium chlorite and sodium hypochlorite. Further examples of biocides include biguanides, aldehydes, ethylene oxide, isothiazolinones, iodophores, DuPont's Kordek® MLX (aqueous composition of 2-methyl-4-isothiazolin-3-one ), the commercially available KATHON (trademark) and NEOLENE (trademark) products from Dow Chemicals, and the Preventol (trademark) product range from Lanxess. In one embodiment, the biocide is Kordek™ MLX. The amount of biocide used in the polishing composition can vary from about 0.00005% to 0.001% by weight or from about 0.0001% to 0.0005% by weight. In some embodiments, the biocide is present in an amount of about 0.0001%, about 0.00013% or about 0.00015% by weight. In one embodiment, in the polishing composition, the biocide is present at about 0.0001% to 0.001% by weight.

In other embodiments, additional ingredients may include surfactants. Surfactants can be anionic, cationic, nonionic, or zwitterionic and can increase the lubricity of a vehicle or composition. Non-limiting examples of surfactants include dodecyl sulfate, sodium or potassium salts, lauryl sulfate, secondary alkanesulfonates, alcoholethoxylates, acetylenediol surfactants, quaternary ammonium based surfactants, betaine amphoteric surfactants, amino acid derivative-based surfactants, and any combination thereof. Examples of suitable commercially available surfactants include the TRITON™, TERGITOL™ and DOWFAX™ families of surfactants from Dow Chemicals. Suitable surfactants may also include polymers containing ethylene oxide (EO) and propylene oxide (PO) groups. An example of an EO-PO polymer is TETRONIC (trademark) 90R4 from BASF Chemicals. The amount of surfactant used in the polishing composition can vary from about 0.0005% to 0.15% by weight, preferably from 0.001% to 0.05% by weight, more preferably from 0.0025% to 0.025% by weight.

In other embodiments, the additional component may include a separate solvent called a co-solvent. Non-limiting examples of co-solvents include, but are not limited to, alcohols (such as methanol or ethanol), ethyl acetate, tetrahydrofuran, alkanes, tetrahydrofuran, dimethylformamide, toluene, ketones (such as acetone), aldehydes, and esters. Not limited. Other non-limiting examples of cosolvents include dimethylformamide, dimethylsulfoxide, pyridine, acetonitrile, glycols and mixtures thereof. The cosolvent is in various amounts, preferably from a lower limit of about 0.0001, 0.001, 0.01, 0.1, 0.5, 1, 5, or 10% (wt %) to an upper limit of about 0.001, 0.01, 0.1, 1, 5, 10, 15, 20 , 25, or 35% (% by weight) can be used.

As described herein, polishing compositions have specific properties that are greatly influenced by both the type and amount of components in the composition. Therefore, in order to maintain desired properties, there are cases where it is necessary to exclude certain materials from the composition.

The polishing slurry of the present invention can be prepared by any suitable technique, many of which are known to those skilled in the art. The polishing composition may be prepared in a batch or continuous process. In general, the polishing composition can be prepared by combining the components disclosed herein in any order. The term "component" used herein includes individual components (eg, abrasives, molybdenum removal rate improvers, oxidizing agents, organic acids, corrosion inhibitors, etc.) and any combination of components. For example, the abrasive can be dispersed in water, the molybdenum removal rate improver and any other additives can be added, and the components can be mixed by any method that can be incorporated into the polishing composition. If desired, the pH can be further adjusted at any appropriate time by adding an acid, base, or buffer as needed.

In some embodiments, the polishing composition is stable at 50°C for at least 1, 2, 3, 4, 5, 6, or 7 days. In some embodiments, the polishing composition is stable at 50°C for at least 1 week, at least 2 weeks, at least 3 weeks, or at least 4 weeks. Here, the stability of the polishing composition can be evaluated by calculating the above-mentioned ([B]-[T])/[C]. For example, in the polishing composition, ([B]-[T])/[C] is preferably 0.5 or less, more preferably 0.3 or less, even more preferably 0.1 or less, still more preferably 0.05 or less. , more preferably 0.04, and most preferably 0.03 or less.

Accordingly, as described herein, in some embodiments is a polishing composition comprising an abrasive, a molybdenum removal rate improver, an organic acid, an oxidizing agent, a corrosion inhibitor and water, wherein the abrasive is cationically modified silica; The molybdenum removal rate improver is an iron salt; The oxidizing agent is a peroxide; corrosion inhibitors are positively charged amino acids; The polishing composition has a pH of about 2 to about 5.

As in any embodiment described above, a polishing composition wherein the cationically modified silica is present in a concentration of about 0.1% to about 1.5% by weight.

As in any of the embodiments described above, the polishing composition wherein the iron salt is present in a concentration of about 0.0001% to about 0.0007% by weight.

As in any of the embodiments described above, the polishing composition wherein the peroxide is present in a concentration of about 0.1% to about 2.5% by weight.

As in any of the embodiments described above, the polishing composition wherein the positively charged amino acid is present at a concentration of about 0.01% to about 0.15% by weight.

As in any one of the above embodiments, a polishing composition in which an amino group is covalently bonded to the surface of the cation-modified silica.

As in any one of the embodiments described above, the polishing composition wherein the iron salt is selected from the group consisting of iron (III) nitrate, iron (II) sulfate and iron (III) sulfate.

As in any embodiment described above, the polishing composition wherein the organic acid is malonic acid.

As in any embodiment described above, the polishing composition wherein the peroxide is hydrogen peroxide.

As in any one of the above embodiments, the polishing composition wherein the positively charged amino acid is selected from the group consisting of lysine, histidine and arginine.

As in any embodiment described above, the polishing composition further comprises a pH adjuster. In a further embodiment, the polishing composition wherein the pH adjuster is an acid present at a concentration of about 0.01% to about 0.10% by weight. In a further embodiment, the acid is nitric acid.

As in any of the embodiments described above, the polishing composition has a pH of about 2 to about 4.

As in any of the embodiments described above, the polishing composition further comprises a biocide present at a concentration of about 0.0001% to about 0.001% by weight.

As in any of the embodiments described above, the polishing composition wherein the abrasive has a positive zeta potential ranging from about +10 mV to about +50 mV.

As in any of the embodiments described above, the polishing composition has a molybdenum static etch rate of less than about 20.

As in any of the embodiments described above, the polishing composition has a molybdenum removal rate of at least about 200 A/min.

As in any of the embodiments described above, the polishing composition has a TEOS polishing rate of less than about 50 A/min.

As in any embodiment described above, the polishing composition wherein the ratio of the molybdenum removal rate to the molybdenum static etch rate of the polishing composition is at least about 20.

As in any embodiment described above, the polishing composition has a Mo:TEOS polishing rate selectivity ratio of at least about 4.5.

As in any embodiment described above, the polishing composition is stable for at least one week. In one embodiment, the pH of the composition remains unchanged after at least one week. In another embodiment, the electrical conductivity (EC) of the composition remains unchanged after at least one week. In some embodiments, the electrical conductivity is greater than zero to about 1.0 mS/cm, greater than zero to about 0.50 mS/cm, greater than zero to about 0.25 mS/cm, greater than zero to about 0.15 mS/cm, greater than zero to about 0.10 mS/cm, greater than zero to about 0.05 mS/cm, or greater than zero to about 0.03 mS/cm. In some embodiments, the electrical conductivity is between about 0.01 mS/cm and about 1.0 mS/cm, between about 0.02 mS/cm and about 0.50 mS/cm, or between about 0.03 mS/cm and about 0.1 mS/cm. In some embodiments, the electrical conductivity is about 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, or 0.15 mS/cm. In some embodiments, the upper limit of electrical conductivity is about 0.25 mS/cm, about 0.20 mS/cm, about 0.18 mS/cm, about 0.16 mS/cm, about 0.14 mS/cm, about 0.12 mS/cm, about 0.10 mS/cm, about 0.08 mS/cm, about 0.07 mS/cm, about 0.06 mS/cm, about 0.05 mS/cm, about 0.04 mS/cm, or about 0.03 mS/cm. In a further embodiment, the electrical conductivity ranges from about 0.2 mS/cm to about 1.0 mS/cm.

As in any embodiment described above, an amino group is covalently bonded to the surface of the cation-modified silica, the molybdenum removal rate improver is iron (II) nitrate, the oxidizing agent is hydrogen peroxide, the organic acid is malonic acid, and the corrosion inhibitor is arginine. , a polishing composition.

Further, in some embodiments, a polishing composition comprising an abrasive, a molybdenum removal rate improver, an organic acid, an oxidizing agent, a corrosion inhibitor, and water, wherein the abrasive is cation-modified present at a concentration of about 0.1% by weight to about 1.5% by weight. silica; The molybdenum removal rate improver is an iron salt present in a concentration of about 0.0001% to about 0.0007% by weight; The oxidizing agent is a peroxide present in a concentration of about 0.1% to about 2.5% by weight; The corrosion inhibitor is a positively charged amino acid present in a concentration of about 0.01% to about 0.15% by weight; The polishing composition has a pH of about 2 to about 4.

As in any embodiment described above, the polishing composition wherein the iron salt is selected from the group consisting of iron(III) nitrate, iron(II) sulfate and iron(III) sulfate; organic acid is malonic acid; peroxide is hydrogen peroxide; A polishing composition, wherein the positively charged amino acid is selected from the group consisting of lysine, histidine and arginine.

As in any of the embodiments described above, the polishing composition further comprises a pH adjusting agent present at a concentration of about 0.01% to about 0.10% by weight.

As in any embodiment described above, the polishing composition wherein the pH adjuster is nitric acid.

C. Methods of Using Polishing Compositions

The polishing compositions described herein are useful for polishing any suitable substrate. In one embodiment, the substrate being polished may be any suitable substrate comprising at least one molybdenum layer. Suitable substrates include, but are not limited to, flat panel displays, integrated circuits, memories or rigid disks, metals, interlayer dielectric (ILD) devices, semiconductors, microelectromechanical systems, ferroelectrics, and magnetic heads.

As another example, a substrate including a silicon oxide layer may be polished using a polishing composition. In another embodiment, a substrate including a silicon layer may be polished using a polishing composition. Suitable substrates include, but are not limited to, flat panel displays, integrated circuits, memory or rigid disks, metals, semiconductors, ILD devices, microelectromechanical systems (MEMS), ferroelectrics, and magnetic heads.

The substrate may further include at least one other layer, for example an insulating layer. The insulating layer can be a metal oxide, porous metal oxide, glass, organic polymer, fluorinated organic polymer, or any other suitable high-K or low-K insulating layer. The insulating layer may include, consist essentially of, or consist of silicon oxide, SiN, or a combination thereof. The silicon oxide layer can include, consist essentially of, or consist of any suitable silicon oxide, many of which are known in the art. For example, the silicon oxide layer may be tetraethoxysilane (TEOS), high density plasma (HDP) oxide, borosilicate glass (BPSG), high aspect ratio process (HARP) oxide, spin-on dielectric (SOD) oxide, chemical vapor deposition ( CVD) oxide, plasma excited tetraethyl orthosilicate (PETEOS), thermal oxide, or undoped silicate glass. In certain embodiments, the silicon oxide layer is tetraethoxysilane (TEOS). The substrate may further include a metal layer. In certain embodiments, the metal layer is molybdenum.

Accordingly, as described herein, in some embodiments there is a method of using the polishing composition comprising the steps of a) preparing the polishing composition according to claim 1 described herein; b) preparing a substrate comprising a molybdenum-containing layer; and c) polishing the substrate with the polishing composition to provide a polished substrate.

As in any of the embodiments described above, the method wherein the substrate is a semiconductor.

As in any of the embodiments described above, the method further comprises a silicon oxide layer.

As with any of the embodiments described above, a method that results in a Mo:TEOS removal rate selectivity greater than about 5.

As with any of the embodiments described above, a method that results in a Mo static etch rate of less than about 20.

D. Examples

The following preparations and examples are provided to enable those skilled in the art to more clearly understand and practice the present invention. They should not be regarded as limiting the scope of the present invention, but merely as illustrative and representative.

In one aspect, a method of making a polishing composition is disclosed. In another aspect, a method of using a polishing composition for polishing a material is disclosed.

[Example 1: Polishing conditions]

Materials and devices used:

<Polishing conditions>

Polishing device: ALLIED precision polishing device MultiPrep system (Allied High Tech Products, Inc.)

Rotational speed of grinding wheel: 200 rpm

· Head rotation speed: 60pm

· Flow rate: 15mL/min

Downforce: 1.5psi

Grinding time: 60 seconds

Pad: Dupont vision pad 6000

· Dilution factor: 6 times

<Conditions of static etching rate>

1 minute at 25℃

Mo test piece: 2 kA Mo wafer (manufactured by Advantiv) (1.5 inches long × 1.5 inches wide × a molybdenum film formed on a Si substrate with a thickness of about 780 μm and a thickness of 2000 Å)

[Example 2: Polishing Experiment]

Using the slurries described in Tables 1A to 5A, the following TEOS substrates and Mo substrates were polished according to the above polishing conditions.

TEOS substrate: 10 kA TEOS wafer (manufactured by Advantiv) (1.5 inches long × 1.5 inches wide × a TEOS film formed on a Si substrate with a thickness of about 780 μm to a thickness of 10000 Å)

Mo substrate: 2 kA Mo wafer (manufactured by Advantiv) (1.5 inches long × 1.5 inches wide × a molybdenum layer formed on a Si substrate with a thickness of about 780 μm and a thickness of 2000 Å)

[Polishing speed]

As for the polishing rate, using Resmap (manufactured by Creative Design Engineering, Inc.), the polished film thickness (Å) was calculated by measuring the average of the film thickness values of 17 points in the surface of each substrate before and after polishing, and the polished film It was calculated by dividing the thickness (Å) by the polishing time (minutes).

[Static Etch Rate]

Using the slurry described in Tables 1A to 5A, etching was performed using Mo test pieces according to the above static etching rate conditions. The static etching rate is calculated by measuring the film thickness before and after etching using Resmap (manufactured by Creative Design Engineering, Inc.) to calculate the etched film thickness (Å), and dividing the etched film thickness (Å) by the etching time (minutes). was calculated by doing

[Preparation of slurries A to V]

Slurries A to V described in Tables 1A to 5A were prepared. 100 parts by weight of the entire slurry, positively charged high-purity colloidal silica (product name PL-3C (manufactured by Fuso Chemical Co., Ltd.), secondary particle diameter 70 nm, surface area 80 m / g) whose surface was modified with aminosilane as an abrasive , ferric nitrate as a molybdenum removal rate improver, the compounds listed in Tables 1A to 5A as a corrosion inhibitor, malonic acid as an organic acid, hydrogen peroxide as an oxidizing agent, and 1,2-benzothiazolin-3-one as a biocide , Slurries A to V were prepared by mixing nitric acid as a pH adjuster and water (deionized water) as a dispersion medium. In addition, the addition amount (content) of each component is the amount (weight% with respect to the total weight of the slurry) shown in Tables 1A to 5A, and the addition amount (content) of the pH adjuster is such that the pH of the slurries A to V is 2.7 (liquid temperature: 25 ° C.) ) was set as the amount of The zeta potentials of the abrasives in the slurries A to V were +20 to +50 mV. In addition, slurries A to S, although not described in Tables 1A to 4A, contain hydrogen peroxide water at 1.53% by weight. In addition, the amount of each component in Tables 1A to 5A means weight% with respect to the total weight (100% by weight) of the slurry, and is simply expressed as "%" in the table.

[Evaluation results]

As shown in Tables 1A and 1B, amino acids were screened as Mo corrosion inhibitors. The ratio of Mo RR to Mo static etch rate (SER) ("Mo SER/Mo RR ratio") was used as a parameter to judge the performance of the slurry formulation. The higher the value of the Mo SER/Mo RR ratio, the lower the SER and the higher the Mo RR, so the blend is more desirable. Positively charged amino acids such as arginine, histidine and lysine were judged to be excellent corrosion inhibitors of Mo. For example, the Mo RR/Mo SER ratios observed in slurries C, D and E were higher than those of other slurries. In addition, slurries C and D resulted in the lowest Mo SER among the slurries evaluated in Table 1B. Slurries containing neutral amino acids such as glycine, cysteine, serine, proline, valine, or alanine all resulted in high Mo SERs.

More notably, by adding malonic acid, the Mo SER increased from 94 Å/min to 154 Å/min (slurries A and B, respectively). All of the slurries in Table 1A contain positively charged high purity colloidal silica PL-3C as an abrasive. All concentrations are based on POU formulations. All slurries contained hydrogen peroxide at a concentration of 1.53% by weight in POU.

[Table 1A]

[Table 1B]

Tables 2A and 2B show the effect of particle concentration by Slurry C as a base formulation. The particle concentration in the slurry refers to the abrasive concentration. All of the slurries in Table 2A contained positively charged high-purity colloidal silica PL-3C (Fuso Chemical Co., Ltd.) as an abrasive. As shown in Table 2B, TEOS RR and Mo SER increase with increasing particle concentration. All concentrations are based on POU formulations. All slurries contained hydrogen peroxide at a concentration of 1.53% by weight in POU.

[Table 2A]

[Table 2B]

Tables 3A, 3B show the effect of ferric nitrate concentration. All of the slurries in Table 3A contained positively charged high-purity colloidal silica PL-3C (Fuso Chemical Co., Ltd.) as an abrasive. As shown in Table 3B, Mo SER decreased as the ferric nitrate concentration increased. Slurry C had the highest Mo RR/Mo SER ratio, mainly because Mo SER was low. This result indicates that the etching performance improves as the ferric nitrate concentration increases. Even when the ferric nitrate concentration was increased by more than two times (slurry O), the Mo SER did not decrease any more. All concentrations are based on POU formulations. All slurries contained hydrogen peroxide at a concentration of 1.53% by weight in POU.

[Table 3A]

[Table 3B]

Tables 4A, 4B show the effect of arginine concentration. All of the slurries in Table 4A contain positively charged high purity colloidal silica PL-3C as an abrasive. When arginine concentration increases, Mo RR, Mo SER and TEOS RR decrease. The Mo RR/Mo SER ratio by slurry C is the highest among the slurries shown in Table 4A. The Mo RR/Mo SER ratio by slurry R is lower than that of slurry C, and it is believed (but not bound by theory) that this effect is due to a decrease in Mo RR due to an increase in the corrosion inhibitor concentration. All concentrations are based on POU formulations. All slurries contained hydrogen peroxide at a concentration of 1.53% by weight in POU.

[Table 4A]

[Table 4B]

Tables 5A and 5B show the effect of the concentration of the oxidizing agent (such as hydrogen peroxide) on the previously prepared slurry C. All of the slurries in Table 5A contain positively charged high purity colloidal silica PL-3C as an abrasive. As the oxidizer concentration increases, both Mo SER and Mo RR increase. An oxidant concentration of 1.53 wt% resulted in the highest Mo RR/Mo SER ratio. All concentrations are based on POU formulations.

[Table 5A] Effect of hydrogen peroxide

[Table 5B]

Thus, as disclosed herein, the use of positively charged colloidal silica is an embodiment of a formulation with positively charged amino acids as corrosion inhibitors at pH 2.7. In some embodiments, histidine, arginine and lysine have been characterized as corrosion inhibitors for Mo.

[Stability evaluation]

100 mL each of the slurries C to E, L, N, O to R, and T to V was sampled and placed in a 100 mL measuring cylinder. After that, when left without stirring for 2 hours, the particle concentration in the lower 50 mL of the measuring cylinder ([B], in g/mL units) and the particle concentration in the upper 50 mL of the measuring cylinder ([T], g The value of ([B] - [T]) / [C] was calculated by dividing the difference in /mL unit) by the total concentration of particles in the abrasive composition ([C], g/mL unit). The value of ([B]-[T])/[C] for slurries C and D was (0.00136-0.00134)/0.0135=0.0148. In addition, the value of ([B]-[T])/[C] of the slurries E, L, N, O to R, T to V was 0.03 or less.

In addition, after about 1 kg of slurries C to E, L, N, O to R, and T to V were left still at 50°C, the state of the slurry was visually observed one week later. As a result, it was confirmed that the abrasive did not settle in the slurries A to W and were uniform solutions. Therefore, it was confirmed that the slurries C to E, L, N, O to R, and T to V were stable at 50°C for one week.

It will be clear to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the present invention. Other aspects of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that this specification and examples be considered as examples only, and that the actual scope and spirit of the present invention be indicated by the scope of the following claims.

This application is based on US Provisional Application No. 63/250,837 filed on September 30, 2021, the disclosures of which are incorporated herein by reference in their entirety.

Claims (17)

A polishing composition containing an abrasive, a molybdenum polishing rate improver, an organic acid, an oxidizing agent, a corrosion inhibitor and water,
the abrasive is cationically modified silica;
the molybdenum removal rate improver is an iron salt;
the oxidizing agent is a peroxide;
the corrosion inhibitor is a positively charged amino acid;
The polishing composition, wherein the polishing composition has a pH of about 2 to about 5. The polishing composition according to claim 1, wherein an amino group is covalently bonded to the surface of the cation-modified silica. The polishing composition according to claim 1, wherein the iron salt is selected from the group consisting of iron(III) nitrate, iron(II) sulfate and iron(III) sulfate. The polishing composition according to claim 1, wherein the peroxide is hydrogen peroxide. The polishing composition according to claim 1, wherein the positively charged amino acid is selected from the group consisting of lysine, histidine and arginine. The polishing composition according to claim 1, further comprising a pH adjuster. The polishing composition according to claim 1, further comprising nitric acid. The polishing composition according to claim 1, wherein the pH is from about 2 to about 4. The polishing composition of claim 1 , wherein the abrasive has a positive zeta potential ranging from about +10 mV to about +50 mV. The method of claim 1, wherein an amino group is covalently bonded to the surface of the cation-modified silica,
The molybdenum removal rate improver is iron (II) nitrate,
The oxidizing agent is hydrogen peroxide,
The organic acid is malonic acid,
The polishing composition, wherein the corrosion inhibitor is arginine. A polishing composition containing an abrasive, a molybdenum polishing rate improver, an organic acid, an oxidizing agent, a corrosion inhibitor and water,
the abrasive is cationically modified silica present in a concentration of about 0.1% to about 1.5% by weight;
the molybdenum removal rate improver is an iron salt present in a concentration of about 0.0001% to about 0.0007% by weight;
the oxidizing agent is a peroxide present in a concentration of about 0.1% to about 2.5% by weight;
the corrosion inhibitor is a positively charged amino acid present in a concentration of about 0.01% to about 0.15% by weight;
The polishing composition, wherein the polishing composition has a pH of about 2 to about 4. The method according to claim 1, wherein the iron salt is selected from the group consisting of iron(III) nitrate, iron(II) sulfate and iron(III) sulfate;
the organic acid is malonic acid;
the peroxide is hydrogen peroxide;
The polishing composition, wherein the positively charged amino acid is selected from the group consisting of lysine, histidine and arginine. 13. The polishing composition of claim 12, further comprising a pH adjusting agent present at a concentration of about 0.01% to about 0.10% by weight. The polishing composition according to claim 13, wherein the pH adjuster is nitric acid. A method of polishing a substrate,
a) preparing the polishing composition according to claim 1;
b) preparing a substrate comprising a molybdenum-containing layer; and
c) polishing the substrate with the polishing composition to provide a polished substrate. 16. The method of claim 15, wherein the substrate is a semiconductor. 17. The method of claim 16, wherein the substrate further comprises a silicon oxide layer.