Derivatized Polyamino Acids

Abstract

The composition comprises, consists of, or consists essentially of a polymer containing derivatized amino acid monomer units. The chemical-mechanical polishing composition comprises an aqueous liquid carrier, abrasive particles dispersed in the liquid carrier, and a cationic polymer having derivatized amino acid monomer units. A method of chemical-mechanical polishing includes utilizing the chemical-mechanical polishing composition to remove at least a portion of a metal or dielectric layer from a substrate, thereby polishing the substrate.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS none

[0002] Disclosed embodiments relate to derivatized polyamino acids. Particular embodiments relate to chemical mechanical polishing slurries that include derivatized polyamino acids, such as derivatized ε-poly-L-lysine. [Background technology]

[0003] Numerous chemical mechanical polishing (CMP) operations are used in both front-end (FEOL) and back-end (BEOL) processing of semiconductor devices. For example, shallow trench isolation (STI) is a FEOL process used to form inlay tetraethyl orthosilicate (TEOS) patterns in silicon wafers prior to the formation of transistors. Tungsten plug interconnect process and copper interconnect dual damascene process are BEOL processes used to form a network of metal wires that connect device transistors. In these processes, a metal layer is deposited into an opening formed in a dielectric material (e.g., TEOS). Chemical mechanical polishing (CMP) is used to remove excess metal from the dielectric material, thereby forming conductive plugs and / or interconnects therein. An interlayer dielectric (ILD) material (e.g., TEOS) is deposited between metal interconnect levels to provide electrical isolation between the levels.

[0004] As the size of semiconductor device features continues to shrink, meeting local and global planarity requirements becomes increasingly difficult in CMP operations, specifically metal CMP operations. Array erosion (also called simply erosion or oxide erosion) and plug and line pullback (also called dishing) are known to compromise planarity and overall device integrity. Additionally, localized metal etching / corrosion loss can cause electrical contact problems that degrade electrical performance. There is a need in the industry for metal CMP slurries (or compositions), such as tungsten CMP compositions, that improve planarity and reduce metal loss during metal CMP operations.

[0005] Additionally, as known to those skilled in the art of semiconductor manufacturing, cobalt is sometimes selected over tungsten as the level 1 interconnect material due to improved electrical performance. However, cobalt is highly susceptible to corrosion. Therefore, inhibiting cobalt corrosion is extremely important in cobalt CMP polishing compositions. Inhibiting cobalt corrosion can also be extremely important for tungsten CMP operations (tungsten polishing compositions must migrate to lower cobalt structures in the stack to prevent cobalt corrosion). There is a new need for CMP slurries that can efficiently planarize cobalt and inhibit cobalt corrosion. Summary of the Invention [Means for solving the problem]

[0006] The composition comprises, consists of, or consists essentially of a polymer comprising derivatized amino acid monomer units. The polymer may be dispersed in a liquid carrier. A chemical mechanical polishing composition for polishing a substrate comprises an aqueous liquid carrier, abrasive particles dispersed in the liquid carrier, and a cationic polymer having derivatized amino acid monomer units. In one embodiment, the abrasive particles may comprise colloidal silica and the cationic polymer may comprise derivatized polylysine. A method of chemical mechanical polishing a substrate is further disclosed. The method may include contacting the substrate with the polishing composition, moving the polishing composition relative to the substrate, and abrading the substrate to remove a portion of a metal or dielectric layer from the substrate, thereby polishing the substrate. [Brief description of the drawings]

[0007] [Figure 1] For a more complete understanding of the disclosed subject matter, and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying Figure 1, which illustrates the proton NMR spectrum of Composition 1A in Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The composition comprises, consists of, or consists essentially of a polymer comprising a derivatized amino acid monomer unit. For example, the composition may comprise a polymer having a derivatized amino acid monomer (i.e., a derivatized polyamino acid). In certain embodiments, the derivatized polyamino acid may be dissolved in a liquid carrier (e.g., an aqueous liquid carrier). Advantageously, the composition can inhibit metal corrosion, particularly corrosion of tungsten metal and cobalt metal and alloys.

[0009] Also disclosed is a chemical mechanical polishing (CMP) composition for polishing a substrate. The polishing composition includes an aqueous liquid carrier, abrasive particles dispersed in the liquid carrier, and a cationic polymer having derivatized amino acid monomer units (also referred to herein as a derivatized polyamino acid or a derivatized polyamino acid compound). The CMP composition may include virtually any cationic polymer containing derivatized amino acid monomers, including homopolymers and copolymers. As known to those skilled in the art, copolymers include two or more different monomer units. In a preferred copolymer, at least one of the monomer units is a derivatized amino acid.

[0010] The disclosed compositions and methods can provide various technical advantages and improvements over the prior art. For example, the disclosed compositions can inhibit metal corrosion and / or etching, specifically of tungsten and cobalt metal layers. The disclosed compositions can further improve tungsten removal rates and improve topography of metal CMP operations (improving patterned wafer performance).

[0011] Of course, the disclosed CMP compositions can be advantageously utilized for metal or dielectric CMP operations, including tungsten CMP operations, cobalt CMP operations, and advanced dielectric CMP operations. The disclosed compositions are particularly suited for bulk removal and / or buff metal CMP operations, which may be referred to by those skilled in the art as first and second step CMP operations. As known by those skilled in the art, bulk removal operations require higher removal rates, whereas buff operations require lower defect levels. The disclosed CMP compositions can also be advantageously utilized for single step CMP operations. Although the disclosed embodiments are particularly suited for tungsten and cobalt CMP operations, they are not intended to be limited to any particular metal or dielectric CMP operation.

[0012] The polishing composition contains abrasive particles suspended in a liquid carrier. The liquid carrier is used to facilitate deposition of the abrasive particles and any chemical additives on the surface of the substrate to be polished (e.g., planarized). The liquid carrier may be any suitable carrier (e.g., solvent), including lower alcohols (e.g., methanol, ethanol, etc.), ethers (e.g., dioxane, tetrahydrofuran, etc.), water, and mixtures thereof. Preferably, the liquid carrier comprises, consists essentially of, or consists of water, more preferably deionized water.

[0013] The abrasive particles suspended in the liquid carrier may comprise substantially any suitable abrasive material, such as metal oxide particles, diamond particles, and / or ceramic particles. Metal oxide particles may include, for example, silica, ceria, and / or alumina abrasive particles, including colloidal and / or fumed metal oxide particles. Ceramic particles may include materials such as cubic boron nitride or silicon carbide. The disclosed embodiments are not expressly limited with respect to the abrasive particles.

[0014] In certain embodiments (e.g., Examples 1-9 disclosed below), the abrasive may comprise colloidal silica. The term colloidal silica particles as used herein refers to silica particles prepared via a wet process rather than a pyrogenic or flame hydrolysis process that produces structurally distinct particles. Colloidal silica particles may be agglomerated or non-agglomerated. Non-agglomerated particles are individually discrete particles. These particles may be spherical or approximately spherical in shape, but may also have other shapes (e.g., approximately elliptical, square, or rectangular cross-section). Agglomerated particles form aggregates having a generally irregular shape by clustering or bonding together a plurality of discrete particles. Agglomerated colloidal silica particles are disclosed, for example, in commonly assigned U.S. Pat. No. 9,309,442.

[0015] In certain other embodiments (e.g., Example 10 disclosed below), the abrasive may include ceria particles. The use of ceria particles may be advantageous, for example, in certain dielectric CMP operations and improved dielectric CMP operations. Substantially any suitable ceria abrasive particles may be utilized, including wet process ceria (e.g., HC60® commercially available from Rhodia), sintered ceria (e.g., as disclosed in commonly assigned U.S. Pat. No. 9,505,952), and cubic ceria (e.g., as disclosed in commonly assigned U.S. Provisional Patent No. 62 / 924,328). The disclosed embodiments are not limited in these respects.

[0016] The abrasive particles may have virtually any suitable particle size. The particle size of the particles suspended in the liquid carrier can be defined in the industry using various means. For example, particle size can be defined as the diameter of the smallest sphere that contains the particle and can be measured using a number of commercially available instruments, including, for example, a CPS Disc Centrifuge, Model DC24000HR (available from CPS Instruments, Prairieville, Louisiana) or a Zetasizer® available from Malvern Instruments®. The average particle size of the abrasive particles can be about 5 nm or more (e.g., about 10 nm or more, about 20 nm or more, about 30 nm or more, about 40 nm or more, about 50 nm or more, or about 60 nm or more). The average particle size of the abrasive particles can be 300 nm or less (e.g., about 250 nm or less, about 200 nm or less, about 180 nm or less, or about 150 nm or less). Thus, the abrasive particles can have an average particle size within the range bounded by any two of the above endpoints. For example, the average particle size of the abrasive particles may be about 5 nm to about 300 nm (eg, about 20 nm to about 200 nm, about 40 nm to about 200 nm, or about 50 nm to about 150 nm).

[0017] The polishing composition may contain substantially any suitable amount of abrasive particles. The polishing composition may contain about 0.01 wt% or more (e.g., about 0.02 wt% or more, about 0.05 wt% or more, about 0.1 wt% or more, about 0.2 wt% or more, or 0.5 wt% or more) of abrasive particles at the point of use. The polishing composition may contain about 20 wt% or less (e.g., about 10 wt% or less, about 5 wt% or less, about 3 wt% or less, or about 1 wt% or less) of abrasive particles at the point of use. Thus, the point of use concentration of abrasive particles in the polishing composition may be within a range bounded by any two of the above endpoints. For example, the amount of abrasive particles in the polishing composition may be about 0.01 wt% to about 20 wt% (e.g., about 0.02 wt% to about 10 wt%, about 0.05 wt% to about 5 wt%, about 0.1 wt% to about 3 wt%, about 0.1 wt% to about 1 wt%).

[0018] In embodiments in which the abrasive particles comprise silica (e.g., colloidal silica or pyrogenic silica), the silica particles preferably have a positive charge in the polishing composition. The charge on a dispersed particle, e.g., a silica particle, is generally referred to in the art as a zeta potential (or kinetic potential). The zeta potential of a particle refers to the difference between the charge of the ions surrounding the particle and the charge of the bulk solution of the polishing composition (e.g., the liquid carrier and any other components dissolved in the liquid carrier). The zeta potential typically depends on the pH of the aqueous medium. In a given polishing composition, the isoelectric point of a particle is defined as the pH at which the zeta potential is zero. As the pH increases or decreases from the isoelectric point, the surface charge (and thus the zeta potential) correspondingly decreases or increases (to negative or positive zeta potential values). The zeta potential of a dispersion, e.g., a polishing composition, can be obtained using commercially available instruments, such as a Zetasizer available from Malvern Instruments, a ZetaPlus Zeta Potential Analyzer available from Brookhaven Instruments, and / or an electroacoustic spectrometer available from Dispersion Technologies, Inc.

[0019] In certain embodiments, the abrasive particles include colloidal silica particles having a positive charge of about 6 mV or more (e.g., about 10 mV or more, about 15 mV or more, or about 20 mV or more). The positive charge of the colloidal silica particles in the polishing composition may be about 50 mV or less (e.g., about 45 mV or less, or about 40 mV or less). Thus, the positive charge of the colloidal silica particles may be within a range bounded by any two of the above endpoints. For example, the positive charge of the colloidal silica particles may be about 6 mV to about 50 mV (e.g., about 10 mV to about 45 mV, about 15 mV to about 45 mV, or about 20 mV to about 40 mV).

[0020] Although the disclosed embodiments are not limited in this respect, it may be advantageous for the colloidal silica particles to have a permanent positive charge. By permanent positive charge, we mean that the positive charge on the silica particles is not easily reversible, for example, through flushing, dilution, filtration, and the like. The permanent positive charge may be the result of, for example, a covalent bond between a cationic compound and the colloidal silica. The permanent positive charge contrasts with a reversible positive charge, which may be the result of, for example, an electrostatic interaction between a cationic compound and the colloidal silica. However, as used herein, a permanent positive charge of at least 6 mV means that the zeta potential of the colloidal silica particles remains above 6 mV after a three-step ultrafiltration test detailed in commonly assigned U.S. Pat. No. 9,238,754 (incorporated herein by reference in its entirety).

[0021] Colloidal silica particles having a permanent positive charge in the polishing composition can be obtained by treating the particles with at least one aminosilane compound, for example as disclosed in commonly assigned U.S. Patent Nos. 7,994,057 and 9,028,572. Alternatively, colloidal silica particles having a permanent positive charge in the polishing composition can be obtained by incorporating a chemical species, for example an aminosilane compound, into the colloidal silica particles, for example as disclosed in commonly assigned U.S. Patent No. 9,422,456.

[0022] The polishing composition further comprises a cationic polymer having a derivatized amino acid monomer. The CMP composition may comprise virtually any cationic polymer containing a derivatized amino acid monomer unit, including homopolymers and copolymers. As known to those skilled in the art, a copolymer comprises two or more different monomer units. In suitable copolymers, at least one of the monomer units is a derivatized amino acid. As described in more detail below, many of the disclosed cationic polymers can be considered as copolymers that comprise underivatized and derivatized amino acid monomer units.

[0023] The cationic polymer may be derivatized from a non-derivatized polyamino acid. It goes without saying that a polyamino acid compound is a polymer derivatized from amino acid monomers. An example of a polyamino acid suitable for derivatization is shown in Formula 1 below: [ka]

[0024] In the exemplary cationic polymer shown in formula 11, Q is any linking group and may include virtually any linking group, including, for example, a branched or straight chain alkyl group. X1 and X2 may be virtually any group, including, for example, hydrogen or an alkyl group. R1 may be virtually any suitable substituent, including, for example, OH, H, or an alkyl group.

[0025] As discussed above, the cationic polymer of Formula 1 may be derivatized to obtain a cationic polymer having derivatized amino acid monomers. An example of a derivatized polyamino acid is shown in Formula 2. [ka]

[0026] In the example of the derivatized polymer shown in Formula 2, Q, X1, X2, and R1 are as defined above in relation to Formula 1. The subscripts m and n are used to indicate the repeat units of the polymer. n represents the number of repeat units in the original underivatized polyamino acid, and m represents the number of derivatized amino acid monomer units, so that nm represents the number of remaining underivatized monomer units. The degree of derivatization (or percent derivatization) may be defined as m / n. In certain advantageous embodiments, for example to promote solubility, n may be less than 200, and m / n may be less than about 2 / 3.

[0027] With continued reference to Formula 2, it can be seen that the derivatized monomer unit includes a derivative group R2 attached to the alpha amino group of the derivatized amino acid monomer. In the disclosed embodiments, R2 can include virtually any suitable derivative group. For example, suitable groups include alkylcarbonyl groups, divalent carboacyl groups, alkylurea groups, and alkylsulfonate groups, alkylsulfone groups, and alkylester groups.

[0028] Examples of alkylcarbonyl groups include acetyl, pivaloyl, ethylcarbonyl, and the like. Examples of divalent carboacyl groups include succinyl, octenylsuccinyl, glutaric acid, and methylsuccinyl, and the like. Among the divalent carboacyl groups, succinyl and glutaric acid groups may be preferred due to their solubility. Examples of alkylurea groups include ethylurea, butylurea, cyclohexylurea, and the like. Examples of alkylsulfonate groups include methylsulfonate, dimethylsulfonate, ethylsulfonate, propylsulfonate, butylsulfonate, pentasulfonate, and the like. Examples of alkylsulfone groups include methylsulfone, ethylsulfone, propylsulfone, butylsulfone, pentasulfone, and the like. Examples of alkylester groups include methylester, ethylester, propylester, butylester, and pentaester, and the like.

[0029] Examples of derivatized amino acid monomers are shown in Formulas 3A, 3B, 3C, and 3D (collectively Formula 3), where R2 is an acetyl group (2A), a succinyl group (2B), an ethyl urea group (2C), and a propyl sulfonate group (2D). [ka]

[0030] With continued reference to Formulas 1, 2 and 3, a derivatized cationic polymer can be obtained, for example, by combining a cationic polyamino acid (eg, as shown in FIG. 1) with an appropriate amount of a derivatizing compound.

[0031] In certain embodiments, for example, a derivatized cationic polymer having a divalent carboacyl group can be obtained by adding an appropriate amount of an anhydrous compound containing a divalent carboacyl group to an aqueous solution of a cationic polyamino acid. The pH of the solution can be adjusted to a value above 7 to promote the derivatization of the polyamino acid via a condensation reaction. The degree of derivatization can be controlled by the relative amounts of the polyamino acid and the anhydrous compound.

[0032] In another embodiment, a derivatized cationic polymer having alkylcarbonyl, alkylurea, or alkylsulfonate groups can be obtained by adding an appropriate amount of an alkylcarbonyl compound and an alkylisocyanate compound or a sultone compound to a solution of a cationic polyamino in methanol. The solution can be heated to promote the derivatization of the polyamino acid via a condensation reaction. The methanol can then be removed via evaporation to obtain a derivatized polyamino acid compound. The compound can then be dissolved in water. The degree of derivatization can be controlled by the relative amounts of the polyamino acid and the derivatizing compound and / or by the reaction time.

[0033] Although the disclosure describes a process for obtaining a derivatized cationic polymer by combining a polyamino acid (polymer) with a derivatizing compound, it is understood that the disclosed embodiments are not so limited. For example, in another embodiment, an amino acid monomer may first be derivatized (e.g., via reaction with one or more of the above-mentioned groups) and then polymerized. The disclosed embodiments are expressly not limited with respect to any method by which a derivatized cationic polymer is obtained.

[0034] The disclosed polishing compositions may comprise virtually any suitable derivatized polyamino acid. For example, the derivatized polyamino acid may comprise derivatized polyarginine, derivatized polyornithine, derivatized polyhistidine, and derivatized polylysine. In a preferred embodiment, the derivatized polyamino acid compound comprises derivatized polylysine, derivatized polyarginine, and derivatized polyhistidine. The most preferred derivatized polyamino acid compound comprises derivatized polylysine.

[0035] It is understood that polylysine may include ε-polylysine and / or α-polylysine, which are composed of D-lysine and / or L-lysine, and thus may include α-poly-L-lysine, α-poly-D-lysine, ε-poly-L-lysine, ε-poly-D-lysine, and mixtures thereof. In certain preferred embodiments, the derivatized polylysine is derivatized ε-poly-L-lysine (ε-poly-L-lysine is commonly referred to in the chemical arts as εPLL or EPL). It is understood that formula 1 shows ε-poly-L-lysine, and formula 2 shows derivatized ε-poly-L-lysine when Q is C2H4 and X1, X2, and R1 are H.

[0036] The derivatized cationic polymer has an acid dissociation coefficient (pK a For example, the titratable group may have a dissociation constant of from about 5 to about 14, or preferably from about 6 to about 11.

[0037] It is further understood that the derivatized polyamino acid compound may be used in any accessible form, for example, the conjugate acid or base and salt forms of the derivatized polyamino acid may be used instead of (or in addition to) the acid. The term "acid" used in this context to describe useful derivatized polyamino acid compounds is intended to mean the derivatized polyamino acid and any form accessible by adjusting the pH to modify any titratable functional groups that may be present. Such forms include its conjugate base or acid and any other salts thereof. For example, the term "polylysine" refers to the polylysine amino acid and its conjugate acid formed by protonating the amine functional groups.

[0038] Suitable derivatized polyamino acid compounds may have virtually any molecular weight and polydispersity index. For example, the molecular weight of the derivatized polyamino acid compound may be from about 1 to about 100 kDa. However, it should be understood that the disclosed embodiments are not limited by the molecular weight or polydispersity index of the derivatized polyamino acid compound.

[0039] In certain CMP compositions (e.g., metal CMP compositions), the use of one or more derivatized polyamino acid compounds is intended to inhibit metal corrosion, such as corrosion of tungsten and / or cobalt plugs and lines in IC devices. Such corrosion inhibition can further be advantageous because it can reduce recession (i.e., dishing) of the plugs and lines and reduce array erosion.

[0040] The amount of derivatized polyamino acid compound in the polishing composition can vary, for example, depending on the specific derivatized polyamino acid compound used, the degree of derivatization, and any other components in the composition.Of course, there may be trade-offs when selecting the amount of derivatized polyamino acid compound.For example, increasing the amount of derivatized polyamino acid can further reduce the corrosion rate, but at the expense of reducing the overall CMP removal rate.Therefore, the amount of derivatized polyamino acid can also vary depending on the overall process goal of the CMP operation.

[0041] When the derivatized polylysine is used in a tungsten CMP composition in combination with a hydrogen peroxide oxidizer and a soluble iron-containing catalyst (e.g., derivatized ε-poly-L-lysine), the derivatized polylysine may be present in the composition at the point of use in an amount of about 1 to about 1000 ppm based on the total weight of the composition. The polishing composition may contain about 1 ppm or more (e.g., about 5 ppm or more, about 10 ppm or more, about 15 ppm or more, or about 20 ppm or more) of the derivatized polylysine at the point of use. The polishing composition may contain about 1000 ppm or less (e.g., about 500 ppm or less, about 400 ppm or less, about 200 ppm or less, or about 100 ppm or less) of the derivatized polylysine at the point of use. Thus, the derivatized polylysine may be present in the composition at the point of use in an amount bounded by any of the above endpoints. For example, the derivatized polylysine may be present in the composition at the point of use at a concentration of about 1 to about 1000 ppm (eg, about 5 to about 500 ppm, about 10 to about 400 ppm, or about 20 to about 200 ppm).

[0042] When a derivatized polylysine (e.g., derivatized ε-poly-L-lysine) is used in a cobalt CMP composition, the polishing composition may contain about 1 ppm or more (e.g., about 10 ppm or more, about 20 ppm or more, about 30 ppm or more, or about 50 ppm or more) of the derivatized polylysine at the point of use. The polishing composition may contain about 1000 ppm or less (e.g., about 800 ppm or less, about 500 ppm or less, about 400 ppm or less, or about 300 ppm or less) of the derivatized polylysine at the point of use. Thus, the derivatized polylysine may be present in the polishing composition at the point of use in an amount bounded by any of the above endpoints. For example, the derivatized polylysine may be present in the composition at a concentration of about 1 to about 1000 ppm (e.g., about 10 to about 800 ppm, about 20 to about 500 ppm, or about 40 to about 400 ppm).

[0043] When a derivatized polylysine (e.g., a derivatized ε-poly-L-lysine) is used in an improved dielectric material CMP composition that includes a ceria abrasive, the polishing composition may contain about 1 ppm or more (e.g., about 2 ppm or more, about 5 ppm or more, or about 10 ppm or more) of the derivatized polylysine at the point of use. The polishing composition may contain about 200 ppm or less (e.g., about 150 ppm or less, about 100 ppm or less, or about 50 ppm or less) of the derivatized polylysine at the point of use. Thus, the derivatized polylysine may be present in the polishing composition at the point of use in an amount bounded by any of the above endpoints. For example, the derivatized polylysine may be present in the composition at a concentration of about 1 to about 200 ppm (e.g., about 2 to about 100 ppm, about 5 to about 100 ppm, or about 10 to about 50 ppm).

[0044] The polishing composition may have virtually any suitable pH depending on the end use. For example, the tungsten CMP composition may be generally acidic and have a pH less than about 7. The pH of the tungsten polishing composition may be about 1 or more (e.g., about 1.5 or more, about 2 or more, about 2.5 or more, or about 3 or more). The pH of the tungsten polishing composition may be about 6 or less (e.g., about 5 or less, about 4.5 or less, about 4 or less, or about 3.5 or less). Thus, the polishing composition may have a pH in a range bounded by any of the above values. For example, the pH of the tungsten polishing composition may be about 1 to about 6 (e.g., about 2 to about 5, about 2 to about 4.5, or about 2.5 to about 4.5). The preferred pH of the polishing composition used for bulk tungsten removal may be about 2 to about 4 (e.g., about 2 to about 3.5). The preferred pH of the polishing composition used for the tungsten buffing operation may be from about 3 to about 5 (eg, from about 3 to about 4.5).

[0045] Cobalt polishing compositions are generally approximately neutral or slightly alkaline and may have a pH of about 6 to about 10. For example, the pH of the cobalt polishing composition may be about 6 or more (e.g., about 6.5 or more, about 7 or more, about 7.5 or more, or about 8 or more). The pH of the polishing composition may further be about 10 or less (e.g., about 9 or less, about 8.5 or less, or about 8 or less). Thus, the polishing composition may have a pH in the range bounded by any two of the above endpoints. For example, the pH may be about 6 to about 10 (e.g., about 7 to about 9).

[0046] Of course, the pH of the polishing composition can be achieved and / or maintained by any suitable means (depending, of course, on the desired pH). The polishing composition may include virtually any suitable pH adjusting agent or buffer system. For example, suitable pH adjusting agents may include nitric acid, sulfuric acid, phosphoric acid, phthalic acid, citric acid, adipic acid, oxalic acid, malonic acid, maleic acid, ammonium hydroxide, potassium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, and the like, whereas suitable buffering agents may include phosphates, sulfates, acetates, malonates, oxalates, borates, ammonium salts, propionates, mixtures thereof, and the like.

[0047] The polishing composition may include other optional compounds depending on the particular application. For example, the tungsten CMP composition may further include an optional iron-containing accelerator, a stabilizer, and / or an oxidizer. As used herein, an iron-containing accelerator is an iron-containing compound that enhances the removal rate of tungsten during a tungsten CMP operation. For example, the iron-containing accelerator may include a soluble iron-containing catalyst, such as those disclosed in U.S. Pat. Nos. 5,958,288 and 5,980,775. Such iron-containing catalysts may be soluble in the liquid carrier and may include, for example, ferric (iron III) or ferrous (iron II) compounds, such as iron nitrates, iron sulfates, fluorides, chlorides, bromides, and iodides, as well as iron halides, including perchlorates, perbromates, and periodates, and organic iron compounds, such as iron acetates, carboxylates, acetylacetonates, citrates, gluconates, malonates, oxalates, phthalates, and succinates, and mixtures thereof.

[0048] The iron-containing accelerator may include an iron-containing activator (e.g., a free radical generating compound) or an iron-containing catalyst associated with (e.g., coated or bonded to) the surface of the colloidal silica particles as disclosed in U.S. Patent Nos. 7,029,508 and 7,077,880. For example, the iron-containing accelerator may be bonded to silanol groups on the surface of the colloidal silica particles.

[0049] The amount of iron-containing accelerator in the polishing composition may vary depending on the oxidizer and chemical form of the accelerator used. When the oxidizer is hydrogen peroxide (or one of its analogs) and a soluble iron-containing catalyst (e.g., ferric nitrate or ferric nitrate hydrate) is used, the catalyst may be present in the composition in an amount sufficient to provide about 0.5 to about 3000 ppm Fe at the point of use, based on the total weight of the composition. The polishing composition may contain about 1 ppm or more (e.g., about 2 ppm or more, about 5 ppm or more, or about 10 ppm or more) Fe at the point of use. The polishing composition may contain about 500 ppm or less (e.g., about 200 ppm or less, about 100 ppm or less, or about 50 ppm or less) Fe at the point of use. Thus, the polishing composition may contain a range of Fe bounded by any one of the above endpoints. The composition may contain from about 1 to about 500 ppm Fe (e.g., from about 2 to about 200 ppm, from about 5 to about 100 ppm, or from about 10 to about 50 ppm) at the point of use. Polishing compositions used for bulk tungsten removal may preferably contain from about 5 to about 50 ppm Fe (e.g., from about 10 to about 40 ppm Fe). Polishing compositions used for tungsten buffing operations may preferably contain from about 0.5 to about 20 ppm Fe (e.g., from about 1 to about 10 ppm Fe).

[0050] The embodiment of the polishing composition including the iron-containing accelerator may further include a stabilizer. Without such a stabilizer, the iron-containing accelerator and the oxidizer, if present, may react in a manner that causes the oxidizer to rapidly degrade over time. The addition of a stabilizer tends to reduce the effectiveness of the iron-containing accelerator, so the selection of the type and amount of stabilizer added to the polishing composition may significantly affect the CMP performance. The addition of a stabilizer may cause a stabilizer / accelerator complex to form. This complex inhibits the accelerator from reacting with the oxidizer, if present, while at the same time allowing the accelerator to remain sufficiently active to promote rapid tungsten polishing rates.

[0051] Useful stabilizers include phosphoric acid, organic acids, phosphate compounds, nitriles, and other ligands that bind to metals to reduce reactivity toward hydrogen peroxide decomposition, and mixtures thereof. Acid stabilizers can be used in their conjugated form, e.g., carboxylates can be used in place of carboxylic acids. The term "acid" as used herein to describe useful stabilizers also refers to the conjugate base of an acid stabilizer. The stabilizers can be used alone or in combination, and can significantly reduce the rate at which an oxidizing agent, e.g., hydrogen peroxide, decomposes.

[0052] Preferred stabilizers include phosphoric acid, acetic acid, phthalic acid, citric acid, adipic acid, oxalic acid, malonic acid, aspartic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, glutaconic acid, muconic acid, ethylenediaminetetraacetic acid (EDTA), propylenediaminetetraacetic acid (PDTA), and mixtures thereof. Preferred stabilizers may be added to the compositions of the present invention in amounts of from about 1 equivalent to about 3.0 weight percent or more (e.g., from about 3 to about 10 equivalents) per iron-containing promoter. As used herein, the term "equivalent per iron-containing promoter" means one molecule of stabilizer per iron ion in the composition. For example, 2 equivalents per iron-containing promoter means two molecules of stabilizer for each catalyst ion.

[0053] The polishing composition may optionally further comprise an oxidizer. The oxidizer may be added to the polishing composition during the slurry manufacturing process or immediately prior to the CMP operation (e.g., in a tank located in a semiconductor manufacturing facility). Preferred oxidizers include inorganic or organic per-compounds. Per-compounds, as defined herein, are compounds that contain at least one peroxy group (-O--O-) or that contain an element in its highest oxidation state. Examples of compounds that contain at least one peroxy group include hydrogen peroxide and its adducts, such as urea hydrogen peroxide, percarbonates, organic peroxides, such as benzoyl peroxide, peracetic acid, and di-t-butyl peroxide, monopersulfates (SO5 = ), Dipersulfate (S2O8 =), and sodium peroxide. Compounds containing elements in the highest oxidation state include, but are not limited to, periodic acid, periodates, perbromic acid, perbromates, perchloric acid, perchlorates, perboric acid, and perborates, and permanganates. The most preferred oxidizing agent is hydrogen peroxide.

[0054] The oxidizer may be present in the polishing composition at the point of use in an amount of, for example, about 0.1 to about 10 weight percent. In embodiments in which a hydrogen peroxide oxidizer and a soluble iron-containing accelerator are used, the oxidizer may be present in the polishing composition at the point of use in an amount of about 0.1 to about 6 weight percent (e.g., about 0.2 to about 5 weight percent, about 0.3 to about 4 weight percent, or about 0.5 to about 3 weight percent).

[0055] The cobalt CMP composition may optionally (but does not necessarily) further comprise a cobalt polishing accelerator. The optional cobalt polishing accelerator may be selected from nitrogen-containing organic oxidizers, such as nitro compounds, nitroso compounds, N-oxide compounds, oxime compounds, and combinations thereof. For example, the nitrogen-containing organic oxidizer may include aryl nitro compounds, aryl nitroso compounds, aryl N-oxide compounds, aryl oxime compounds, heteroaryl nitro compounds, heteroaryl nitroso compounds, heteroaryl N-oxide compounds, heteroaryl oxime compounds, and combinations thereof.

[0056] The optional cobalt polishing accelerator can further be selected from non-oxidizing compounds such as N-di(carboxylalkyl)amines, N-di(hydroxyalkyl)amines, N,N-di(hydroxyalkyl)-N-carboxylalkylamines, dicarboxyheterocycles, heterocyclylalkyl alpha amino acids, N-aminoalkyl amino acids, unsubstituted heterocycles, alkyl-substituted heterocycles, carboxylic acids, dicarboxylic acids, tricarboxylic acids, alkylamines, N-aminoalkyl alpha amino acids, and combinations thereof. For example, the polishing composition can optionally include a cobalt accelerator selected from iminodiacetic acid ("IDA"), N-(2-acetamido)iminodiacetic acid ("ADA"), N-methylimidazole, picolinic acid, dipicolinic acid, 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid, glycine, bicine, triethylamine ("TEA"), etidronic acid, N-methylmorpholine, malonic acid, 2-piperidinesulfonate, citric acid, and combinations thereof.

[0057] In any embodiment including a cobalt polishing accelerator, the accelerator may be present in the polishing composition at the point of use at a concentration of about 1 mM or more (e.g., about 5 mM or more, about 10 mM or more, about 20 mM or more, or about 40 mM or more). The cobalt polishing accelerator may be present in the polishing composition at the point of use at a concentration of about 200 mM or less (e.g., about 150 mM or less, about 100 mM or less, about 80 mM or less, or about 60 mM or less). Needless to say, the cobalt polishing accelerator may be present in the polishing composition at a concentration bounded by any two of the above endpoints. For example, the cobalt polishing accelerator may be present in the polishing composition at the point of use at a concentration of about 1 mM to about 200 mM (e.g., about 5 mM to about 150 mM, about 10 mM to about 100 mM, or about 20 mM to about 60 mM).

[0058] The polishing composition may optionally further comprise a biocide. The biocide may comprise any suitable biocide, such as an isothiazolinone biocide. The amount of biocide in the polishing composition may be from about 1 ppm to about 500 ppm (e.g., from about 1 ppm to about 200 ppm by weight).

[0059] The polishing composition can be prepared using any suitable technique. Many of these techniques are known to those skilled in the art. The polishing composition can be prepared in a batch or continuous process. Generally speaking, the polishing composition can be prepared by combining its components in any order. As used herein, "component" includes individual ingredients (e.g., abrasive particles, derivatized polyamino acids, etc.).

[0060] For example, abrasive particles (e.g., silica) may be dispersed in an aqueous liquid carrier. Other ingredients, such as derivatized polyamino acids and biocides, may then be added and mixed by any method that allows these ingredients to be incorporated into the polishing composition. For any composition that includes an oxidizer, it goes without saying that the oxidizer may be added at any time during the preparation of the polishing composition. For example, the oxidizer may be added immediately prior to the CMP operation (e.g., within about 1 minute, or within about 10 minutes, or within about 1 hour, or within about 1 day, or within about 1 week before the CMP operation). The polishing composition may also be prepared by mixing the ingredients at the substrate surface (e.g., on a polishing pad) during the polishing operation.

[0061] The polishing composition of the present invention may be provided as a concentrate. The concentrate is intended to be diluted with an appropriate amount of water before use. In such an embodiment, the polishing composition concentrate may include the derivatized polyamino acid and any other optional components in amounts such that, upon dilution of the concentrate with an appropriate amount of water (and any optional oxidizing agent, if not already present in an appropriate amount), each component of the polishing composition will be present in the polishing composition at the point of use in an amount within the appropriate range described above for each component. For example, the abrasive particles and the derivatized polyamino acid may each be present in the polishing composition in an amount that is about twice (e.g., about three times, about four times, or about five times) the point of use concentration described above for each component, so that, when the concentrate is diluted with an equal volume of water (e.g., one volume of water, two volumes of water, three volumes of water, or four volumes of water, respectively) together with an appropriate amount of any optional oxidizing agent, each component will be present in the polishing composition in an amount within the range described above for each component. Furthermore, as will be apparent to one skilled in the art, the concentrate may contain any portion of the water present in the final polishing composition to ensure that the other components are at least partially or completely dissolved in the concentrate.

[0062] The polishing composition of the present invention can be used to polish virtually any substrate, including a metal layer and / or a dielectric layer. In certain embodiments, the polishing composition may be particularly useful for polishing a substrate that includes at least one metal material and at least one dielectric material. For example, certain embodiments may be useful for polishing a substrate that includes tungsten. Other embodiments may be useful for polishing a substrate that includes cobalt. As known to those skilled in the art, metal conductors are generally deposited on one or more barrier layers, including, for example, titanium and / or titanium nitride (TiN). The dielectric layer may be a metal oxide, such as a silicon oxide layer derived from tetraethyl orthosilicate (TEOS), a porous metal oxide, a porous or non-porous carbon-doped silicon oxide, a fluorine-doped silicon oxide, a glass, an organic polymer, a fluorinated organic polymer, or any other suitable high or low k insulating layer.

[0063] The polishing method of the present invention is particularly suitable for use in conjunction with a chemical mechanical polishing (CMP) apparatus. As known to those skilled in the art, the substrate is polished when it is contacted with a polishing pad and the polishing composition of the present invention, and then the polishing pad and the substrate are moved relative to each other to polish at least a portion of the substrate. The method of the present invention removes a portion of the silicon oxide material from the substrate by providing the composition of the present invention described above, contacting the substrate (e.g., a wafer) with the polishing composition of the present invention, moving the polishing composition relative to the substrate, and polishing the substrate, thereby polishing the substrate. Typically, the apparatus includes a platen that moves during use and has a velocity resulting from an orbital, linear, or circular motion, a polishing pad that contacts the platen and moves with the platen during the movement, and a carrier that holds the substrate to be polished by contacting and moving against the surface of the polishing pad. Polishing of a substrate is accomplished by placing the substrate in contact with a polishing pad and the polishing composition of the present invention, and then moving the polishing pad relative to the substrate, thereby polishing the substrate by abrading at least a portion of the substrate (e.g., tungsten, cobalt, titanium, titanium nitride, and / or the dielectric materials described herein).

[0064] The substrate can be planarized or polished with the chemical mechanical polishing composition using any suitable polishing pad (e.g., polishing surface). Suitable polishing pads include, for example, woven and non-woven polishing pads. Furthermore, suitable polishing pads can include any suitable polymer having a variety of densities, hardnesses, thicknesses, compressibility, ability to rebound when compressed, and compression moduli. Suitable polymers include, for example, polyvinyl chloride, polyvinyl fluoride, nylon, fluorocarbon, polycarbonate, polyester, polyacrylate, polyether, polyethylene, polyamide, polyurethane, polystyrene, polypropylene, co-formed products thereof, and mixtures thereof.

[0065] Although CMP polishing compositions and methods are described in detail above, it should be understood that the disclosed embodiments are not strictly limited to chemical mechanical polishing. The disclosed embodiments may include an aqueous solution of a derivatized polyamino acid, such as a derivatized polylysine. For example, the disclosed compositions may include one or more derivatized polyamino acids dissolved in a liquid carrier that includes or consists of water. The disclosed compositions may include a polymer that includes a derivatized amino acid monomer. The polymer may be in a solid form (e.g., a granular form) or may be dissolved in the liquid carrier. The derivatized amino acid monomer may include any of the derivative groups described above in connection with formulas 1-3. For example, the derivative group may include an alkylcarbonyl group, a divalent carboacyl group, an alkylurea group, and an alkylsulfonate group, an alkylsulfone group, or an alkyl ester group.

[0066] Needless to say, the disclosure includes numerous embodiments, examples of which include the following:

[0067] In a first embodiment, a composition comprises, consists of, or consists essentially of a polymer having derivatized amino acid monomer units.

[0068] A second embodiment may include the first embodiment, wherein the polymer has the formula: [ka] This includes compounds based on the formula:

[0069] Q is any linking group, X1 and X2 are virtually any groups, R1 is H, OH, or an alkyl group, and R2 is a derivative group.

[0070] A third embodiment may include the second embodiment, wherein R2 includes at least one of an alkyl urea group, and an alkyl sulfonate group.

[0071] A fourth embodiment may include the third embodiment, wherein the alkyl urea groups include ethyl, butyl, and cyclohexyl urea groups, and the alkyl sulfonate groups include methyl, dimethyl, ethyl, propyl, butyl, and pentasulfonate groups.

[0072] A fifth embodiment may include the second embodiment, wherein R2 includes an ethylurea group, a butylurea group, a cyclohexylurea group, or a propylsulfonate group.

[0073] In a sixth embodiment, the composition comprises, consists of, or consists essentially of water and a cationic polymer comprising derivatized amino acid monomer units.

[0074] A seventh embodiment may include the sixth embodiment, wherein the cationic polymer has the formula: [ka] This includes compounds based on the formula:

[0075] Q is any linking group, X1 and X2 are virtually any groups, R1 is H, OH, or an alkyl group, and R2 is a derivative group.

[0076] An eighth embodiment may include the seventh embodiment, wherein R2 includes at least one of an alkyl urea group, and an alkyl sulfonate group.

[0077] A ninth embodiment may include the eighth embodiment, wherein the alkyl urea groups include ethyl, butyl, and cyclohexyl urea groups, and the alkyl sulfonate groups include methyl, dimethyl, ethyl, propyl, butyl, and pentasulfonate groups.

[0078] A tenth embodiment may include the seventh embodiment, wherein R2 includes an ethylurea group, a butylurea group, a cyclohexylurea group, or a propylsulfonate group.

[0079] In an eleventh embodiment, a chemical-mechanical polishing composition comprises an aqueous liquid carrier, abrasive particles dispersed in the liquid carrier, and a cationic polymer having derivatized amino acid monomer units.

[0080] A twelfth embodiment may include the eleventh embodiment, wherein the abrasive particles comprise a colloidal silica abrasive having a permanent positive charge of at least 10 mV.

[0081] A thirteenth embodiment may include any one of the first, sixth, and eleventh to twelfth embodiments, wherein the derivatized amino acid monomer unit includes a derivative group attached to an alpha amino group in the monomer unit.

[0082] A fourteenth embodiment may include any one of the first, sixth, and eleventh to thirteenth embodiments, wherein the polymer includes at least one of a derivatized polylysine, a derivatized polyarginine, and a derivatized polyhistidine.

[0083] A fifteenth embodiment may include any one of the first, sixth, and eleventh to fourteenth embodiments, wherein the polymer comprises a derivatized ε-poly-L-lysine.

[0084] The sixteenth embodiment may include any one of the sixth and eleventh to fifteenth embodiments, including about 1 to about 1000 ppm of cationic polymer.

[0085] The seventeenth embodiment may include any one of the sixth and eleventh to sixteenth embodiments, wherein the cationic polymer has an acid dissociation constant (pK a ).

[0086] The eighteenth embodiment may include any one of the first, sixth, and eleventh to seventeenth embodiments, wherein the cationic polymer has the formula: [ka] This includes compounds based on the formula:

[0087] Q is any linking group, X1 and X2 are virtually any groups, R1 is H, OH, or an alkyl group, and R2 is a derivative group.

[0088] The nineteenth embodiment may include any one of the second, seventh, or eighteenth embodiments, wherein R2 includes at least one of an alkylcarbonyl group, a divalent carboacyl group, an alkylurea group, and an alkylsulfonate group, an alkylsulfone group, and an alkylester group.

[0089] The twentieth embodiment may include the nineteenth embodiment, wherein the alkylcarbonyl group includes at least one of an acetyl group, a pivaloyl group, and an ethylcarbonyl group.

[0090] The twenty-first embodiment may include the nineteenth embodiment, wherein the divalent carboacyl group includes at least one of a succinyl group, an octenylsuccinyl group, a glutaric acid group, and a methylsuccinyl group.

[0091] The twenty-second embodiment may include the nineteenth embodiment, wherein the alkyl urea group includes at least one of an ethyl urea group, a butyl urea group, and a cyclohexyl urea group.

[0092] A twenty-third embodiment may include the nineteenth embodiment, wherein the alkylsulfonate groups include methylsulfonate groups, dimethylsulfonate groups, ethylsulfonate groups, propylsulfonate groups, butylsulfonate groups, and pentasulfonate groups.

[0093] The twenty-fourth embodiment may include the nineteenth embodiment, wherein the alkylsulfone group includes at least one of a methylsulfone group, and an ethylsulfone group, a propylsulfone group, a butylsulfone group, and a pentasulfone group.

[0094] The twenty-fifth embodiment may include the nineteenth embodiment, wherein the alkyl ester group comprises at least one of a methyl ester group, an ethyl ester group, a propyl ester group, a butyl ester group, and a pentaester group.

[0095] A twenty-sixth embodiment may include any one of the second, seventh, and eighteenth through twenty-fifth embodiments, wherein the polymer or cationic polymer comprises a derivatized ε-poly-L-lysine, where Q is CH and X1, X2, and R1 are H, and R2 comprises at least one of an acetyl group, a succinyl group, an ethyl urea group, a butyl urea group, and a cyclohexyl urea group, or a propyl sulfonate group.

[0096] The twenty-seventh embodiment may include any one of the second, seventh, and eighteenth to twenty-sixth embodiments, wherein n is less than 200.

[0097] The twenty-eighth embodiment may include any one of the second, seventh, and eighteenth to twenty-seventh embodiments, wherein m / n is less than 2 / 3.

[0098] A twenty-ninth embodiment may include any one of the eleventh to twenty-seventh embodiments, further including an iron-containing promoter and a stabilizer bound to the iron-containing promoter.

[0099] A thirtieth embodiment may include the twenty-ninth embodiment, further including hydrogen peroxide.

[0100] A thirty-first embodiment may include any one of the twenty-ninth to thirtieth embodiments and has a pH of about 1 to about 5.

[0101] The thirty-second embodiment may include any one of the eleventh to twenty-eighth embodiments, further including a cobalt polishing accelerator.

[0102] A thirty-third embodiment may include the thirty-first embodiment and have a pH of about 6 to about 10.

[0103] The thirty-fourth embodiment may include any one of the eleventh to twenty-eighth embodiments, wherein the abrasive particles include ceria.

[0104] A thirty-fourth embodiment includes a method of chemically mechanically polishing a substrate, the method including: (a) contacting the substrate with a polishing composition comprising: (i) an aqueous liquid carrier; (ii) abrasive particles dispersed in the liquid carrier; and (iii) a cationic polymer having derivatized amino acid monomer units; (b) moving the polishing composition relative to the substrate; and (c) abrading the substrate to remove a portion of at least one of a metal layer and a dielectric layer from the substrate, thereby polishing the substrate.

[0105] A thirty-sixth embodiment may include the thirty-fifth embodiment, in which the metal includes at least one of tungsten and cobalt.

[0106] A thirty-seventh embodiment may include any one of the thirty-fifth to thirty-sixth embodiments, wherein the abrasive particles include colloidal silica having a permanent positive charge of at least 10 mV.

[0107] A thirty-eighth embodiment may include any one of the thirty-fifth through thirty-seventh embodiments, wherein the metal layer comprises tungsten, and the polishing composition further comprises: (i) hydrogen peroxide; (ii) an iron-containing accelerator; (iii) a stabilizer bound to the soluble iron-containing accelerator, the stabilizer being selected from the group consisting of phosphoric acid, phthalic acid, citric acid, adipic acid, oxalic acid, malonic acid, aspartic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, glutaconic acid, muconic acid, ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, and mixtures thereof; and (iv) a pH of about 1 to about 5.

[0108] A thirty-ninth embodiment may include any one of the thirty-fifth through thirty-seventh embodiments, wherein the metal layer comprises cobalt, and the polishing composition further comprises (i) a cobalt polishing accelerator, and (ii) a pH of about 6 to about 10.

[0109] The fortieth embodiment may include the thirty-fifth embodiment, wherein the dielectric layer comprises at least one of a silicon oxide material and a silicon nitride material, and the abrasive particles comprise ceria.

[0110] The 41st embodiment may include any one of the 35th to 40th embodiments, wherein the cationic polymer has the following formula: [ka] This includes compounds based on the formula:

[0111] Q is any linking group, X1 and X2 are virtually any groups, R1 is H, OH, or an alkyl group, and R2 is a derivative group.

[0112] A forty-second embodiment can include the forty-first embodiment, wherein R2 includes at least one of an alkylcarbonyl group, a divalent carboacyl group, an alkylurea group, and an alkylsulfonate group.

[0113] The 43rd embodiment may include one of the 41st and 42nd embodiments, wherein the cationic polymer comprises a derivatized ε-poly-L-lysine, where Q is C2H4 and X1, X2 and R1 are H.

[0114] Example 1 Five compositions (aqueous cationic polymer solutions) were prepared as follows: 100 grams of a 25 weight percent aqueous solution of ε-poly-L-lysine (εPLL) was combined with 175 grams of deionized water in a flask. The starting εPLL had an average monomer unit number, n, of about 32. Succinic anhydride granules were added to the solution with mixing, which dissolved over a few minutes. The pH of the solution was adjusted to above 7 using KOH. The pH-adjusted solution was stirred overnight to facilitate the derivatization of ε-poly-L-lysine on the alpha amino acids. The final compositions included aqueous solutions with about 9 weight percent of derivatized polyamino acids. Further details regarding the preparation of each aqueous solution as well as the degree of derivatization are shown in Table 1. Table 1 [Table 1]

[0115] Proton NMR( 1 Compositions 1A-1E were evaluated by H NMR to estimate the degree of derivatization. 30-40 mg of aqueous composition samples were dissolved in 1.0 g DO at ambient conditions. NMR spectra were obtained on a 400 MHz NMR using solvent suppression technique with the following settings: D1=30 sec, DS=4 scans, and NS=8 scans.

[0116] An example of a spectrum obtained from composition 1A is shown in the figure. Note that the peak designated M02 is assigned to the methylene protons in the succinic acid side chain (within the derivative group) of derivatized εPLL (α and β protons in formula 4 below). The main chain methylene protons (γ, δ, ε and γ', δ', ε' protons in formula below) are assigned to peak M01. [ka]

[0117] The degree of derivatization (succinylation in this example) was calculated using the following formula: The M01 area and M02 area represent the total peak areas of the M01 and M02 peaks.

number

[0118] The degree of derivatization of Composition 1A was calculated to be about 19 percent based on the NMR spectrum shown in the figure.

[0119] Example 2 Two acetylated compositions (aqueous cationic polymer solutions 2A and 2B) were prepared as follows: εPLL was precipitated for several hours by adding dimethylformamide to the aqueous εPLL solution (from Example 1) in a weight ratio of 7.5:1 dimethylformamide:εPLL solution. The precipitated εPLL was collected and dissolved in methanol. The solution was reacted with methyl acetate at 60° C. for a first and second hour. After 9 days of reaction time, the degree of substitution was 34% (2A) and after 22 days of reaction time, the degree of substitution was 56% (2B). The degree of substitution was determined using proton NMR as described in the examples. These aqueous compositions are summarized in Table 2. Table 2 [Table 2]

[0120] Example 3 Five compositions (aqueous cationic polymer solutions) were prepared as follows: εPLL was precipitated for several hours by adding dimethylformamide to the aqueous εPLL solution (from Example 1) in a weight ratio of 7.5:1 dimethylformamide:εPLL solution. The precipitated εPLL was collected (about 4 grams) and dissolved in methanol. The derivatization compound (propane sultone, ethyl isocyanate, butyl isocyanate, or cyclohexyl isocyanate in this example) was added to the methanol solution. The solution was stirred overnight at 50° C. to facilitate derivatization (substitution of alkylsulfonate groups (3A and 3B) or alkylurea groups (3C, 3D, and 3E) on the alpha amino acids of ε-poly-L-lysine). The final solution was rotary evaporated to remove methanol and then dissolved in water to the desired concentration. Further details regarding the preparation of each aqueous solution and the degree of derivatization are shown in Table 3. Table 3 [Table 3]

[0121] Compositions 3A-3E were evaluated by proton NMR to estimate the degree of derivatization using the same procedure as described above in Example 1.

[0122] Example 4 Tungsten static etch rates were evaluated for 21 polishing compositions (Controls A4, B4, C4, and D4, and Examples 4A, 4B, 4C, 4D, 4E, 4F, 4G, 4H, 4I, 4J, 4K, 4L, 4M, 4N, 4O, 4P, and 4Q). These compositions are listed in Table 4 along with the corresponding tungsten etch rates. Each composition contained 0.17 weight percent cationic colloidal silica, 0.04 weight percent malonic acid, 0.02 weight percent iron nitrate nonahydrate, 2.5 ppm by weight Kathon® LX biocide, 3 weight percent hydrogen peroxide, and a tungsten etch inhibitor. The pH was adjusted to 2.75 with nitric acid or potassium hydroxide.

[0123] In control compositions A4, B4, C4, and D4, the tungsten etch inhibitor was ε-poly-L-lysine at the concentration listed in Table 4. In inventive compositions 4A-4Q, the tungsten etch inhibitor was derivatized ε-poly-L-lysine at the concentration listed in Table 4. Compositions 4A-4Q were prepared by adding an appropriate amount of one of the corresponding compositions 1A-1C, 2A, 2B, or 3A-3E disclosed in Examples 1, 2, and 3 above. The inhibitor concentrations are listed in Table 4 in units of (i) parts per million (ppm) by weight and (ii) micromolar cationic charge concentration. The charge concentration can be calculated by multiplying the number of remaining underivatized monomer units (nm in Equation 2) by the molar concentration of the derivatized polyamino acid, where the charge concentration is a measure of the moles per liter of underivatized alpha amino groups in the derivatized polyamino acid. Alternatively, the cationic charge concentration can be calculated based on the following equation (μM): (Cationic charge concentration CC (μM) is listed as a function of the concentration (ppm by weight) of the derivatized polyamino acid.

number

[0124] ρ represents the density of the composition (density is about 1.0 to about 1.1 for these example compositions), and MW α represents the molecular weight of a derivatized polyamino acid compound per underivatized alpha amino acid and can be calculated as follows:

number

[0125] dd represents the degree of derivatization (m / n shown in Eq. 2), and MW mon represents the molecular weight of the underivatized monomer (in this example, the polylysine monomer), and MW der-mon represents the molecular weight of the derivatized monomer (in this example, the derivatized polylysine monomer unit).

[0126] To obtain the tungsten etch rate corresponding to each polishing composition, the composition was first heated to 60° C., and then hydrogen peroxide was added to a concentration of 3 weight percent. After waiting 5 minutes for the temperature to return to 60° C., a 1 inch square coupon of a Silyb tungsten wafer with an 8000 Å thick tungsten layer was immersed in the polishing composition for 5 minutes. The tungsten removal rate was determined via resistance measurements taken before and after immersion of the wafer in the polishing composition. Table 4 [Table 4]

[0127] As is readily apparent from the results shown in Table 4, many of the compositions of the present invention containing derivatized polylysine inhibitors exhibit tungsten static etch rates that are comparable to or lower than control compositions having the same cationic charge concentration. For example, composition 4H has a tungsten etch rate that is about half that of control C4.

[0128] Example 5 Ten polishing compositions (Controls A5, B5, C5, D5, and E5, and Examples 5A, 5B, 5C, 5D, and 5E) were evaluated for static tungsten etch rates. Each polishing composition contained cationic colloidal silica, 0.04% malonic acid, 0.02% ferric nitrate nonahydrate, 2.5 ppm by weight Kathon® LX biocide, 3 weight percent hydrogen peroxide, and a tungsten etch inhibitor. The pH was adjusted to 2.75 with nitric acid or potassium hydroxide. The cationic colloidal silica particles were prepared as described in Example 7 of U.S. Pat. No. 9,382,450. The silica concentrations are listed in Table 5. The tungsten etch inhibitor was prepared as described above for composition 1B of Example 1. The inhibitor concentrations are also listed in Table 5 in units of (i) parts per million (ppm) by weight and (ii) micromolar cationic charge concentration as described above in Example 4.

[0129] Tungsten blanket wafers (Silyb 2k W Blanket, 200 mm) were polished to endpoint +10% using an Applied Materials Mirra polishing tool, a NexPlanar E6088 polishing pad (available from Cabot Microelectronics), a 3M A122 conditioner (ex situ mode at 8 lbs) with a down force of 3.5 psi, a platen speed of 80 rpm, a head speed of 89 rpm, and a slurry flow rate of 90 ml / min. The tungsten RR was determined by the frag time, which is the point at which the W metal begins to clear (removal rate is 2000 Å divided by the frag time in minutes). Table 5 [Table 5]

[0130] As is readily apparent from the results shown in Table 5, the compositions of the present invention containing the derivatized polyamino acid inhibitors achieved higher removal rates than the control compositions of equal inhibitor weight concentrations.

[0131] Example 6 Erosion and dishing of tungsten patterned wafers were evaluated for two polishing compositions (Control A6 and Example 6A). The control composition (A6) was identical to Control E5 of Example 5. The inventive composition (6A) was identical to composition 5B of Example 5.

[0132] Tungsten patterned wafers (Silyb 2k W 854 line and space pattern, 200 mm) were polished to endpoint +30% using an Applied Materials Mirra polishing tool and a NexPlanar E6088 polishing pad (available from Cabot Microelectronics). The pad was conditioned using a 3M A122 conditioner (ex situ mode at 8 pounds for 24 seconds). The wafers were polished using a down force of 3.5 psi, a platen speed of 80 rpm, a head speed of 89 rpm, and a slurry flow rate of 90 ml / min. The tungsten polishing rate was determined by the frag time, which is the point at which the W metal begins to clear (removal rate is 2000 Å divided by the frag time in minutes). Removal rate data is shown in Table 6A. Erosion and dishing results are shown in Table 6B. Erosion and dishing measurements were obtained using atomic force microscope (AFM) profilometer measurements over corresponding features. Average and Within Die Nonuniformity (WIDNU) erosion and dishing values ​​are also shown in Table 6B. WIDNU is defined in this example as the range (maximum minus minimum) of dishing or erosion values. The patterned wafer features were lines (line widths and spacings are reported). Table 6A [Table 6A] Table 6B [Table 6B]

[0133] As is readily apparent from the results shown in Tables 6A and 6B, composition 6A provides superior erosion and dishing performance compared to the control composition. In particular, composition 6A provides significantly improved average (mean) erosion and dishing, and significantly improved erosion and dishing WIDNU over a wide range of pattern features. As will be apparent to those skilled in the art, achieving low erosion and dishing WIDNU over a wide range of pattern features is a formidable challenge for CMP operators, especially in advanced node CMP applications. The improvements shown in Table 6B represent a significant advantage.

[0134] Example 7 Twelve polishing compositions (Control A7, and Examples 7A, 7B, 7C, 7D, 7E, 7F, 7G, 7H, 7I, 7J, and 7K) were evaluated for cobalt static etch rates. These compositions are listed in Table 7 along with the corresponding cobalt etch rates. Each composition contained 0.5 weight percent colloidal silica, 0.75 weight percent glycine, and 100 ppm by weight of cobalt inhibitor. The pH was adjusted to 8.5 with KOH.

[0135] In control composition A7, the cobalt etch inhibitor was ε-poly-L-lysine. In inventive compositions 7A-7K, the cobalt etch inhibitor was derivatized ε-poly-L-lysine. Compositions 7A-7K were prepared by adding an appropriate amount of one of the corresponding compositions 1A-1E, 2B, or 3A-3E disclosed in Examples 1, 2, and 3 above.

[0136] To obtain the cobalt etch rate corresponding to each polishing composition, the composition was heated to 35° C. Two 1 inch square Silyb Co 2k coupons were immersed in each composition for 3 minutes. The cobalt etch rate was determined via resistance measurements taken before and after immersion. The average values ​​are reported in Table 7. Table 7 [Table 7]

[0137] As is readily apparent from the results shown in Table 7, the compositions of the present invention provide significantly reduced cobalt etch rates as compared to the control composition.

[0138] Example 8 The static etch rates of cobalt were evaluated for fifteen polishing compositions (Controls A8, B8, C8, and D8, and Examples 8A, 8B, 8C, 8D, 8E, 8F, 8G, 8H, 8I, 8J, and 8K). These compositions are listed in Table 8 along with the corresponding cobalt etch rates. Each polishing composition contained 0.5 weight percent colloidal silica, 0.75 weight percent glycine, and a cobalt inhibitor. The pH was adjusted to 8.5 with potassium hydroxide. The type and amount of cobalt inhibitor are listed in Table 8.

[0139] In control compositions A8, B8, C8, and D8, the cobalt etch inhibitor was ε-poly-L-lysine. In inventive compositions 8A-8K, the cobalt etch inhibitor was derivatized ε-poly-L-lysine. Compositions 8A-8K were prepared by adding an appropriate amount of one of the corresponding compositions 1A-1C, 2B, or 3B-3E disclosed in Examples 1, 2, and 3 above.

[0140] To obtain the cobalt etch rate corresponding to each polishing composition, the composition was heated to 35° C. Two 1 inch square Silyb Co 2k coupons were immersed in each composition for 5 minutes. Increasing the time from 3 to 5 minutes increases the signal since it is known that the cobalt etch rate can increase with time (as the cobalt etch can be autocatalytic). The cobalt etch rate was determined via resistance measurements taken before and after immersion. The average values ​​are reported in Table 8. Table 8 [Table 8]

[0141] As is readily apparent from the results shown in Table 8, the compositions of the present invention provide significantly reduced cobalt etch rates as compared to the control composition, with the improvement becoming even more pronounced by increasing the etch time in this example.

[0142] Example 9 Fourteen polishing compositions (Control A9, and Examples 9A, 9B, 9C, 9D, 9E, 9F, 9G, 9H, 9I, 9J, 9K, 9L, and 9M) were evaluated for their static etch (removal) rates of cobalt. Each polishing composition contained 0.5 weight percent colloidal silica (Fuso PL-2), 0.75 weight percent glycine, and a cobalt etch inhibitor. The pH was adjusted to 8.5 with potassium hydroxide. The type and amount of cobalt inhibitor are listed in Table 9.

[0143] In control composition A9, the cobalt etch inhibitor was ε-poly-L-lysine. In inventive compositions 9A-9M, the cobalt etch inhibitor was derivatized ε-poly-L-lysine. Compositions 9A-9M were prepared by adding an appropriate amount of one of the corresponding compositions 1A-1E, 2B, or 3A-3E disclosed in Examples 1, 2, and 3 above.

[0144] Cobalt removal rates were measured on Silyb Co 2k coupons using a Rheometer (ARG-2) with a Fujibo Donut pad with an outer radius of 32 mm and an inner radius of 16 mm. The polishing temperature was 25°C. The down force was 4 N (1.2 psi). The pad rotation speed was 130 rpm. 3 mL of slurry was utilized. The polishing time was 15 seconds. The cobalt removal rates corresponding to each composition are listed in Table 9. Table 9 [Table 9]

[0145] As is readily apparent from the results shown in Table 9, many of the compositions of the present invention provide cobalt removal rates comparable to those achieved using the control compositions, which represents a significant improvement given the reductions in cobalt etch rates disclosed in Examples 7 and 9 above.

[0146] Example 10 Dielectric material polishing rates were evaluated for four polishing compositions (Controls A10 and B10, and Compositions 10A and 10B according to the invention). Each composition contained 150 ppm by weight polyvinylpyrrolidone (5000 g / mol), 676 ppm by weight acetic acid, 0.1% by weight crotonic acid, 100 ppm by weight picolinic acid, 75 ppm by weight Kordex MLX biocide, 0.2% by weight ceria, and εPLL or derivatized εPLL at pH 4. The ceria was the same as that described in Example 1 of commonly assigned U.S. Provisional Patent Application No. 62 / 924,328. Control Compositions A10 and B10 contained 10 and 30 ppm by weight εPLL. Compositions 10A and 10B according to the invention contained 10 and 30 ppm by weight acetylated εPLL (derived from aqueous composition 2B described in Example 2 above).

[0147] Blanket tetraethyl orthosilicate (TEOS), high density plasma (HDP) oxide, and SiN-PE wafers were each polished on a Mirra® tool with a platen speed of 100 rpm, a head speed of 85 rpm, a downforce of 3 psi, and a slurry flow rate of 150 ml / min. The wafers were polished on a NexPlanar® E6088 pad (available from Cabot Microelectronicss Corporation) with in-situ conditioning using a Saesol DS8051 conditioner with a downforce of 6 pounds. The TEOS wafers were obtained from WRS Materials. The TEOS wafers contained a 20 kÅ TEOS layer. The HDP wafers were obtained from Silyb. The HDP wafers contained a 10 kÅ HDP oxide layer. The SiN-PE wafers were obtained from Advantec. The SiN-PE wafers contained a 5 kÅ PE SiN layer. The polishing data is shown in Table 10. All removal rates are listed in angstroms per minute (Å / min). Table 10 [Table 10]

[0148] As is readily apparent from the results shown in Table 10, Composition 10B achieves superior TEOS and HDP removal rates at higher polymer loadings compared to the control Composition B10.

[0149] When "a" and "an" and "the" and similar referents are used in the context of describing the present invention (particularly in the context of the claims below), they should be construed to cover both the singular and the plural unless otherwise indicated or clearly contradicted by context. The terms "comprising", "having", "including" and "containing" should be construed as open-ended terms (i.e., "including, but not limited to") unless otherwise indicated. The recitation of ranges of values ​​herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated, and each separate value is incorporated herein as if it were individually set forth herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or clearly contradicted by context. Any and all examples, or language denoting examples (e.g., "such as") provided herein are merely intended to better illustrate the invention. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0150] Preferred embodiments of the present invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of these preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors anticipate that such variations will be adopted by those of ordinary skill in the art as necessary, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the present invention unless otherwise indicated herein or otherwise clearly contradicted by context. Examples of embodiments of the present invention are listed in the following items [Aspect 1] to [Aspect 33]. [Document name] Claims [Aspect 1] 1. A chemical mechanical polishing composition comprising: an aqueous liquid carrier; abrasive particles dispersed in said liquid carrier; Cationic polymers having derivatized amino acid monomer units A composition comprising: [Aspect 2] 2. The composition of embodiment 1, wherein the abrasive particles comprise a colloidal silica abrasive having a positive charge of at least 10 mV. [Aspect 3] The composition of embodiment 1, wherein the derivatized amino acid monomer unit comprises a derivative group attached to an alpha amino group in the monomer unit. [Aspect 4] 2. The composition of embodiment 1, wherein the cationic polymer comprises at least one of a derivatized polylysine, a derivatized polyarginine, and a derivatized polyhistidine. [Aspect 5] The composition of embodiment 4, wherein the cationic polymer comprises a derivatized ε-poly-L-lysine. [Aspect 6] 2. The composition of embodiment 1, comprising about 1 to about 1000 ppm of a cationic polymer. [Aspect 7] The cationic polymer has an acid dissociation constant (pK a 2. The composition of embodiment 1, having the formula: [Aspect 8] The cationic polymer has the formula:

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Claims

1. 1. A chemical mechanical polishing composition comprising: an aqueous liquid carrier; abrasive particles dispersed in said liquid carrier; The following formula: 【Chemistry 1】 and a cationic polymer comprising a compound based on Including, A composition, wherein Q is any linking group, X 1 and X 2 are any groups, R 1 is H, OH, or an alkyl group, R 2 is a derivative group, R 2 comprises at least one of an alkylcarbonyl group, a divalent carboacyl group, an alkylurea group, and an alkylsulfonate group, an alkylsulfone group, and an alkylester group, n is less than 200, and the cationic polymer comprises a derivatized ε-poly-L-lysine.

2. The composition of claim 1 , wherein the abrasive particles comprise a colloidal silica abrasive having a positive charge of at least 10 mV.

3. The composition of claim 1, comprising 1 to 1000 ppm of a cationic polymer.

4. The cationic polymer has an acid dissociation constant (pK a 2. The composition of claim 1 having a structure comprising:

5. The composition of claim 1 , wherein the alkylcarbonyl group comprises at least one of an acetyl group, a pivaloyl group, and an ethylcarbonyl group.

6. 2. The composition of claim 1, wherein the divalent carboacyl group comprises at least one of a succinyl group, an octenylsuccinyl group, a glutaric acid group, and a methylsuccinyl group.

7. 2. The composition of claim 1, wherein the alkyl urea group comprises at least one of an ethyl urea group, a butyl urea group, and a cyclohexyl urea group.

8. 2. The composition of claim 1, wherein the alkyl sulfonate groups include methyl sulfonate groups, dimethyl sulfonate groups, ethyl sulfonate groups, propyl sulfonate groups, butyl sulfonate groups, and pentasulfonate groups.

9. 2. The composition of claim 1, wherein the alkyl sulfone groups include methyl sulfone groups, and at least one of ethyl sulfone groups, propyl sulfone groups, butyl sulfone groups, and pentasulfone groups.

10. The composition of claim 1 , wherein the alkyl ester group comprises at least one of a methyl ester group, an ethyl ester group, a propyl ester group, a butyl ester group, and a pentaester group.

11. The cationic polymer is 2 H 4 And X 1 , X 2 and R 1 is H, R 2 comprises at least one of an acetyl group, a succinyl group, an ethyl urea group, a butyl urea group, and a cyclohexyl urea group, or a propyl sulfonate group; The composition of claim 1.

12. 2. The composition of claim 1, wherein m / n is less than 2 / 3.

13. The composition of claim 1, further comprising an iron-containing accelerator that enhances tungsten removal rates during tungsten CMP operations, and a stabilizer that inhibits the accelerator from reacting with an oxidizing agent, if present, while at the same time forming a stabilizer / accelerator complex that allows the accelerator to remain sufficiently active to promote rapid tungsten removal rates.

14. The composition of claim 13 further comprising hydrogen peroxide.

15. The composition of claim 13 having a pH of 1 to 5.

16. The composition of claim 1 further comprising a cobalt polishing accelerator.

17. The composition of claim 16 having a pH of 6 to 10.

18. The composition of claim 1 , wherein the abrasive particles comprise ceria.

19. 1. A method of chemically mechanically polishing a substrate, the method comprising: (a) removing the substrate by (i) an aqueous liquid carrier; (ii) abrasive particles dispersed in said liquid carrier; and (iii) a compound of the following formula: 【Chemistry 2】 A cationic polymer comprising a compound based on a cationic polymer, Q being any linking group, X 1 and X 2 being any group, R 1 being H, OH, or an alkyl group, R 2 being a derivative group, R 2 comprising at least one of an alkylcarbonyl group, a divalent carboacyl group, an alkylurea group, and an alkylsulfonate group, n being less than 200, said cationic polymer comprising a derivatized ε-poly-L-lysine; contacting the polishing composition comprising (b) moving the polishing composition relative to the substrate; and (c) grinding the substrate to remove a portion of at least one of the metal layer and the dielectric layer from the substrate, thereby polishing the substrate. A method comprising:

20. 20. The method of claim 19, wherein the metal layer comprises at least one of tungsten and cobalt.

21. 20. The method of claim 19, wherein the abrasive particles comprise colloidal silica having a permanent positive charge of at least 10 mV.

22. the metal layer comprises tungsten and the polishing composition comprises: (i) hydrogen peroxide; (ii) an iron-containing accelerator that enhances the removal rate of tungsten during a tungsten CMP operation; and (iii) a stabilizer that inhibits the accelerator from reacting with the oxidizing agent, if present, while at the same time forming a stabilizer / accelerator complex that allows the accelerator to remain sufficiently active to promote said rapid tungsten removal rate, said stabilizer being selected from the group consisting of phosphoric acid, phthalic acid, citric acid, adipic acid, oxalic acid, malonic acid, aspartic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, glutaconic acid, muconic acid, ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, and mixtures thereof; (iv) a pH of 1 to 5; and 20. The method of claim 19, further comprising:

23. the metal layer comprises cobalt and the polishing composition comprises: (i) a cobalt polishing accelerator; (ii) a pH of 6 to 10; and 20. The method of claim 19, further comprising:

24. 20. The method of claim 19, wherein the dielectric layer comprises at least one of a silicon oxide and a silicon nitride material and the abrasive particles comprise ceria.

25. The cationic polymer is 2 H 4 And X 1 , X 2 and R 1 The method of claim 19, comprising a derivatized ε-poly-L-lysine where

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