Composition and method for removing tungsten and dielectric layers

Abstract

The invention claimed herein relates to a dielectric polishing composition and method thereof. The invention claimed herein particularly relates to a composition comprising: (A) surface-modified colloidal silica particles comprising negatively charged groups on the surface of the particles, wherein the surface-modified colloidal silica particles have a negative charge, a particle size of 60 nm to 200 nm, and a zeta potential of < -35 mV at a pH in the range of > 2.0 to < 6.0; (B) at least one corrosion inhibitor selected from at least one guanidine derivative; (C) at least one iron (III) oxidizing agent; (D) at least one buffering agent selected from at least one acidic amino acid having an isoelectric point (pi) of < 5.0; (E) at least one stabilizer; and (F) an aqueous medium, wherein the pH of the composition is in the range of > 2.0 to < 4.3, and wherein the composition has a polyacrylamide content of < 1 ppm.

Description

Technical Field

[0001] The inventions claimed herein relate to compositions and methods for polishing dielectrics. In particular, the inventions claimed herein relate to compositions and methods that provide high selectivity for the removal of dielectrics relative to tungsten. Background Technology

[0002] The fabrication of integrated circuits (ICs) is a multi-step process. The first step (also known as the front-end process or FEOL step) involves patterning individual devices, such as transistors (e.g., C-MOSFETs), on a semiconductor using appropriate techniques (such as photolithography or ion implantation). Metal wires / plugs and insulating layers (such as dielectrics) are then inserted to interconnect the individual devices (also known as the back-end process or BEOL step). As feature sizes continue to shrink in Very Large Scale Integration (ULSI) technology, multi-level interconnects are required.

[0003] Metals such as tungsten, cobalt, ruthenium, and copper are commonly used as interconnects, and the choice of a particular metal is based on its position in the structure. For example, a common first metal interconnect (metal layer 0) is a tungsten plug inserted into a dielectric layer (such as silicon dioxide). On the other hand, copper is the most common deposited metal during the BEOL step, but for lower interconnect levels (e.g., metal layers 1-4), tungsten and cobalt are typically used.

[0004] CMP (Chemical Mechanical Planarization) has been found to be a key technology enabling the formation of multilevel interconnects because it can initiate both local and global planarization while simultaneously providing excellent surface quality, namely, a superior, defect-free, mirror-like surface finish. Pure mechanical polishing or (fine) grinding will provide excellent planarization, but the surface will become dull. On the other hand, pure chemical polishing (anisotropic etching) will only provide poorer planarization results, but will offer excellent mirror-like surface finish.

[0005] In this paper, CMP utilizes the interaction of chemical and mechanical actions to achieve the desired flatness and smoothness of the surface to be polished. The mechanical action is typically achieved through the interaction of a CMP composition containing finely dispersed abrasive particles with a polishing pad, which is typically pressed against the surface to be polished and mounted on a moving stage. In a typical CMP process step, a rotating wafer holder brings the wafer to be polished into contact with the polishing pad. The CMP composition is typically applied between the wafer and the polishing pad.

[0006] A typical CMP composition or slurry contains one or more abrasive (insoluble / dispersed) components and a soluble component. The chemical action is provided by the soluble component of the CMP composition. Generally, to achieve metal CMP, the chemical composition is tailored by balancing the corrosive components (e.g., acids, bases, or oxidants) with suitable inhibitors. However, it is important that the soluble and insoluble components be compatible to ensure colloidal stability. Unstable colloidal solutions or agglomerates can damage the surface and fine structure of the wafer to be polished by scratching. Therefore, precise selection of the components and their concentrations is essential to obtaining a suitable CMP composition for achieving appropriate planarization and surface quality.

[0007] Furthermore, when designing pastes, depending on the integration scheme, the characteristics of several or all of the aforementioned metals (e.g., etching) may have to be considered. For example, when manufacturing ICs involving tungsten (metal 0), CMP is used to remove the metal and liner / barrier layer capping until a flat metal 0 (or higher) layer is exposed.

[0008] For example, US 6,083,419 A describes a CMP composition comprising a compound capable of etching tungsten and at least one tungsten etching inhibitor, wherein the tungsten etching inhibitor is a compound comprising at least one functional group selected from the group consisting of nitrogen-containing heterocycles without nitrogen-hydrogen bonds, sulfides, oxazolidines, or mixtures of these functional groups.

[0009] In cases such as US 6,083,419 A, since the intended endpoint for such applications is a dielectric (e.g., a silica layer obtained by CVD deposition using tetraethyl orthosilicate or TEOS), prior art slurries are tailored to achieve high tungsten removal rates relative to silica. For example, US 2019 / 0211227 and US 2019 / 0211228 aim to achieve high selectivity for tungsten removal by employing negatively charged, surface-modified colloidal silica particles. As is well known, one consequence of using compositions exhibiting high selectivity for oxide removal is that embedded TEOS / oxide lines / plugs (side-attached by a metal such as tungsten on either side) are preferentially etched to form dish-shaped depressions, hence the name "dishing." A particularly effective measure against this is to achieve very balanced removal rates for both components on both sides of the interface.

[0010] Furthermore, selective removal of the dielectric is crucial for achieving new integrated solutions. US 8,492,277 provides a polishing method involving the use of compositions comprising acyclic organic sulfonic acids to provide highly selective removal rates for silicon oxide and silicon nitride. US 8,513,126 achieves similar results using compositions comprising quaternary ammonium salts. More recently, WO 2023 / 186762 A1 discloses compositions that achieve such high selectivity via the presence of a combination of guanidine derivatives, one or more iron (III) salts, one or more potassium phosphate salts, one or more polyacrylamides, and a suitable stabilizer such as EDTA.

[0011] US 2022 / 0033682 A1 discloses a chemical mechanical polishing composition for polishing tungsten or molybdenum. The composition comprises, is substantially composed of, or consists of: an aqueous liquid carrier, abrasive particles dispersed in the liquid carrier, an amino acid selected from the group consisting of arginine, histidine, cysteine, lysine, and mixtures thereof, an anionic polymer or anionic surfactant, and optionally an amino acid surfactant.

[0012] However, as is well known in the semiconductor development field, trace amounts of undesirable impurities such as alkali metals (e.g., potassium) on the wafer surface can adversely affect performance. Therefore, each component used in CMP compositions must be carefully selected due to its economic impact and the undesirable traces it leaves on the wafer surface as debris / residue. Thus, there is always room for development of improved and more economical compositions. Furthermore, in the presence of metals that are easily removed under acidic conditions (such as tungsten and cobalt), there is an unmet need for compositions and methods that allow for highly selective removal of dielectrics relative to tungsten and / or cobalt while maintaining high surface quality. Summary of the Invention

[0013] Surprisingly, the composition of the invention claimed herein, as described below, was found to provide unexpectedly high selectivity for the removal of tungsten-based dielectrics.

[0014] Therefore, in one aspect of the invention claimed herein, a dielectric polishing composition comprises:

[0015] (A) Surface-modified colloidal silica particles, wherein the surface of these particles contains negatively charged groups, wherein these surface-modified colloidal silica particles...

[0016] The particles have a negative charge.

[0017] Particle sizes ranging from 60 nm to 200 nm, and

[0018] ζ potential ≤ -35 ​​mV at pH range ≥ 2.0 to ≤ 6.0;

[0019] (B) At least one corrosion inhibitor selected from at least one guanidine derivative;

[0020] (C) At least one iron (III) oxidizing agent;

[0021] (D) At least one buffer selected from at least one acidic amino acid having an isoelectric point (pI) of ≤ 5.0;

[0022] (E) at least one stabilizer; and

[0023] (F) Aqueous medium,

[0024] The pH of the composition is in the range of ≥ 2.0 to ≤ 4.3, and

[0025] The composition contains ≤ 1 ppm of polyacrylamide.

[0026] On the other hand, the invention claimed herein relates to a method for manufacturing a semiconductor device, the method comprising chemically and mechanically polishing a substrate (S) used in the semiconductor industry in the presence of a composition as described herein, the substrate (S) comprising:

[0027] (i) Tungsten and / or

[0028] (ii) Tungsten alloys; and

[0029] (iii) At least one dielectric layer selected from silicon, silicon oxide, silicon nitride, or low-k materials.

[0030] On the other hand, the invention claimed herein relates to the use of the composition described herein for polishing a substrate (S) comprising: (i) tungsten and / or (ii) a tungsten alloy; and (iii) at least one dielectric layer.

[0031] The invention claimed herein is associated with at least one of the following objectives:

[0032] (1) The compositions and methods of the invention claimed herein are intended to provide selective removal of dielectric layers relative to other metals such as tungsten and / or cobalt.

[0033] (2) The compositions and methods of the invention claimed herein are designed to provide a high silicon oxide (SiO2) removal rate while ensuring a low tungsten (W) removal rate.

[0034] (3) The compositions and methods of the invention claimed herein are designed to prevent unwanted tungsten etching during chemical mechanical polishing of tungsten (W) substrates.

[0035] (4) The compositions and methods of the invention claimed herein are designed to prevent unwanted dish-shaped depressions in the dielectric / oxide / TEOS layers during chemical mechanical polishing.

[0036] (5) The compositions of the invention claimed herein are intended to provide stable formulations or dispersions in which no phase separation or agglomeration occurs.

[0037] (6) The composition of the invention claimed herein is intended to provide a suitable dielectric removal rate while preventing undesirable surface defects and ensuring high surface quality.

[0038] Other objects, advantages, and applications of the invention claimed herein will become apparent to those skilled in the art from the following detailed description. Detailed Implementation

[0039] The following detailed descriptions are merely exemplary in nature and are not intended to limit the invention claimed herein or its application and uses. Furthermore, they are not intended to be bound by any theories presented in the foregoing technical field, background art, summary of the invention, or the following detailed descriptions.

[0040] As used herein, the terms “comprising” and “comprised of” are synonymous with “including” or “containing” and are inclusive or open-ended, and do not exclude additional unlisted members, elements, or method steps. It should be understood that, as used herein, the terms “comprising” and “comprised of” include the terms “consisting of” and “consists of”.

[0041] Furthermore, the terms “(a)”, “(b)”, “(c)”, “(d)”, etc., used in the specification and claims are used to distinguish similar elements and are not necessarily used to describe a sequential or chronological order. It should be understood that such terms are interchangeable where appropriate, and embodiments of the invention claimed herein can be operated in any order other than those described or shown herein. If the terms “(A)”, “(B)”, and “(C)”, or “(a)”, “(b)”, “(c)”, “(d)”, “(i)”, “(ii)”, etc., relate to steps of a method, use, or measurement, then there is no temporal or time interval continuity between these steps; that is, these steps may be performed simultaneously or there may be time intervals of seconds, minutes, hours, days, weeks, months, or even years between these steps, unless otherwise indicated in the application above or below.

[0042] The different aspects of the invention claimed herein are defined in more detail in the following paragraphs. Each aspect so defined may be combined with any one or more other aspects unless expressly indicated otherwise. In particular, any feature indicated as preferred or advantageous may be combined with any one or more other features indicated as preferred or advantageous.

[0043] Throughout this specification, references to "an embodiment," "an embodiment," or "a preferred embodiment" mean that a particular feature, structure, or property described in connection with that embodiment is included in at least one embodiment of the invention claimed herein. Therefore, the phrases "in one embodiment," "in an embodiment," or "in a preferred embodiment" appearing in different places throughout this specification do not necessarily all refer to the same embodiment, but may refer to the same embodiment. Furthermore, in one or more embodiments, features, structures, or properties may be combined in any suitable manner, as will be apparent to those skilled in the art from this disclosure. Moreover, although some embodiments described herein include some but not others of features included in other embodiments, combinations of features from different embodiments are intended to be within the scope of this subject matter and form different embodiments, as will be understood by those skilled in the art. For example, in the appended claims, any of the claimed embodiments may be used in any combination.

[0044] Furthermore, the scope defined throughout this specification also includes end values; that is, the range of 1 to 10 means that both 1 and 10 are included within this range. For the avoidance of doubt, the applicant is entitled to obtain any equivalent means in accordance with applicable law.

[0045] For the purposes of the invention claimed herein, '% by weight' or 'wt.%' as used herein refers to the total weight of the composition. Additionally, as described below, the sum of the wt.% of all compounds in each component is 100 wt.%.

[0046] For the purposes of the invention claimed herein, a substrate is defined as a semiconductor wafer made of silicon or a similar half-metal for use in the manufacture of microelectronic devices.

[0047] For the purposes of the invention claimed herein, polishing refers to the chemical and mechanical removal of a specific layer from a substrate during a CMP process. The mechanical action is typically performed using a polishing pad, which is typically pressed against the surface to be polished and mounted on a moving stage. In a typical CMP process step, a rotating wafer holder brings the wafer to be polished into contact with the polishing pad. A CMP composition is typically applied between the wafer and the polishing pad.

[0048] For the purposes of the invention claimed herein, corrosion inhibitors are defined as compounds that form a protective molecular layer on a metal surface.

[0049] For the purposes of the invention claimed herein, a stabilizer is defined as a compound that forms a soluble complex with iron (III) ions, thereby deactivating these ions and preventing them from reacting normally with other elements or ions (such as silicates or phosphates) to produce precipitates or scale. In the absence of a stabilizer, as claimed herein, undesirable interactions have been found between iron (III) oxidants and silicon-based compositions, resulting in colloidal instability of the composition.

[0050] For the purposes of the invention claimed herein, an oxidant is defined as a compound that can oxidize a substrate or one of its layers to be polished.

[0051] For the purposes of the invention claimed herein, a pH adjuster is defined as a compound added to a composition to adjust its pH value to a desired value.

[0052] For the purposes of the invention claimed herein, a buffer is defined as a component that can resist pH changes when an acidic or basic component is added.

[0053] For the purposes of the invention claimed herein, the isoelectric point or pI is the pH at which an amino acid does not carry a net charge (Properties of Analytes and Matrices Determining HPLC Selection, Serban C. Moldoveanu, Victor David, in Selection of the HPLC Method in Chemical Analysis, 2017).

[0054] A lower dielectric constant allows for higher frequencies at which current can operate. Dielectric materials with lower dielectric constants used in metallization in IC manufacturing (primarily in BEOL) are called low-k materials (dielectric constant k, e.g., 3.5 or lower) or ultra-low-k materials (dielectric constant k, e.g., 2.5 and lower). Several low-k materials are available from Applied Materials under the trade name Black Diamond (see also US 6,974,777 B2 or Hosali et al., Analyzing damage from ultralow-k CMP, Solid State Technology, 48 (11) p. 33, 2005). A detailed description of the production of low-k materials and methods for their deposition can be found in McClatchie et al., Low Dielectric Constant Oxide Films Deposited Using CVD Techniques, DUMIC Conference Proceedings, (1998), page 311 and thereafter. For the purposes of the invention claimed herein, low-k materials are materials having a k value (dielectric constant) of less than 3.5, preferably less than 3.0, and more preferably less than 2.7. Ultra-low-k materials are materials having a k value (dielectric constant) of less than 2.4.

[0055] For the purposes of the invention claimed herein, "colloidal silica" refers to silica prepared by the polycondensation of Si(OH)4. The precursor Si(OH)4 can be obtained, for example, by hydrolyzing a high-purity alkoxysilane or by acidifying an aqueous silicate solution. This colloidal silica can be prepared according to U.S. Patent No. 5,230,833 or can be obtained as any of a variety of commercially available products, such as Fuso. ®Products PL-1, PL-2, and PL-3, and Nalco 1050, 2327, and 2329, as well as other similar products available from DuPont, Bayer, Applied Research, Nissan Chemical, Nyacol, and Clariant.

[0056] For the purposes of the invention claimed herein, "particle size" and "average particle size" are used interchangeably. Average particle size is defined as the particle size distribution of colloidal silica particles (A) in an aqueous medium (F) as a percentage of d. 50 value.

[0057] For the purposes of the invention claimed herein, the term "substantially free" means that the composition does not contain any concentration of the component that could affect the polishing function of the composition. Preferably, the component is present in concentrations below 1 ppm, more preferably below 0.1 ppm, and most preferably below the detection limit. For example, preferably, the composition is substantially free of polyacrylamide and / or alkali metals such as potassium, and preferably, the concentration of polyacrylamide and / or alkali metals such as potassium in the composition is below 1 ppm. However, any trace amounts of such components that may remain on the semiconductor surface as part of the residue after the pre-CMP process steps will not impair the polishing applications involving the compositions described herein.

[0058] For the purposes of the invention claimed herein, the average particle size is measured, for example, using dynamic light scattering (DLS) or static light scattering (SLS) methods. These and other methods are well known in the art; see, for example, Kuntzsch, Timo; Witnik, Ulrike; Hollatz, Michael Stintz; Ripperger, Siegfried; Characterization of Slurries Used for Chemical-Mechanical Polishing (CMP) in the Semiconductor Industry; Chem. Eng. Technol; 26 (2003), Vol. 12, p. 1235. This measurement result is commonly referred to in the literature as secondary particle size. Of these methods, DLS is the preferred method.

[0059] For the purposes of the invention claimed herein, dynamic light scattering (DLS) typically utilizes a Malvern Zetasizer ZSP or a Horiba LB-550 V (DLS, Dynamic Light Scattering Measurement) or any other such instrument. This technique measures the hydrodynamic diameter of a particle as it scatters a laser source (e.g., λ = 650 nm) at an angle of, for example, 90° or 173° to the incident light. Variations in the intensity of the scattered light are due to the random Brownian motion of the particle as it passes through the incident beam and are monitored as a function of time. An autocorrelation function, performed by the instrument as a function of time delay, is used to extract the decay constant; smaller particles pass through the incident beam at higher velocities and correspond to faster decay.

[0060] For the purposes of the invention claimed herein, the attenuation constant and the diffusion coefficient D of the inorganic abrasive particles are related. t Proportional and used to calculate granularity according to the Stokes-Einstein equation:

[0061]

[0062] The assumptions are that the suspended particles: (1) have a spherical morphology and (2) are uniformly dispersed (i.e., do not agglomerate) throughout the aqueous medium. This relationship is expected to apply to particle dispersions containing ≤ 1% solids by weight (solid concentration), since the viscosity of the aqueous dispersant does not deviate significantly, where η = 0.96 mPa·s (at T = 22°C). The particle size distribution of gaseous or colloidal silica particle dispersions is typically measured in plastic cuvettes at a solid concentration of 0.1%–1.0%, and diluted with a dispersion medium or ultrapure water if necessary.

[0063] For the purposes of the invention claimed herein, the BET surface area of ​​colloidal silica particles was determined according to DIN ISO 9277:2010-09. This measurement result is commonly referred to in the literature as primary particle size.

[0064] For the purposes of the invention claimed herein, the measurement techniques disclosed are well known to those skilled in the art.

[0065] In one aspect of the invention claimed herein, a dielectric polishing composition comprises:

[0066] (A) Surface-modified colloidal silica particles, wherein the surface of these particles contains negatively charged groups, wherein these surface-modified colloidal silica particles...

[0067] The particles have a negative charge.

[0068] Particle sizes ranging from 60 nm to 200 nm, and

[0069] ζ potential ≤ -35 ​​mV at pH range ≥ 2.0 to ≤ 6.0;

[0070] (B) At least one corrosion inhibitor selected from at least one guanidine derivative;

[0071] (C) At least one iron (III) oxidizing agent;

[0072] (D) At least one buffer selected from at least one acidic amino acid having an isoelectric point (pI) of ≤ 5.0;

[0073] (E) at least one stabilizer; and

[0074] (F) Aqueous medium,

[0075] The pH of the composition is in the range of ≥ 2.0 to ≤ 4.3, and

[0076] The composition contains ≤ 1 ppm of polyacrylamide.

[0077] The composition has a polyacrylamide content of ≤1 ppm, or in other words, the composition is substantially free of polyacrylamide. In some cases, a polyacrylamide content >1 ppm may have a negative impact on the semiconductor morphology. More preferably, the composition has a polyacrylamide content of ≤0.5 ppm, or even more preferably ≤0.1 ppm. For the purposes of the invention claimed herein, the composition is substantially free of polyacrylamide and polyacrylamide copolymers. The polyacrylamide copolymer can be a cationic, anionic, or nonionic polyacrylamide copolymer. The presence of polyacrylamide copolymers in the composition results in undesirable silica (dielectric) dish-like depressions. Most preferably, the amount of polyacrylamide or polyacrylamide copolymers in the composition is ≤0.01 ppm.

[0078] The composition is substantially free of alkali metals. Preferably, the composition contains ≤ 1 ppm of alkali metals. Alkali metals refer to Group I elements of the periodic table, preferably selected from lithium, sodium, potassium, rubidium, cesium, or vanadium. More preferably, the composition is substantially free of lithium, sodium, and potassium, even more preferably substantially free of sodium or potassium, and most preferably substantially free of potassium.

[0079] Alkali metals such as sodium or potassium are typically introduced into CMP compositions via the use of acid / base or buffers; however, their presence can interfere with electronic devices on the wafer surface and adversely affect the final performance. Preferably, the amount of sodium or potassium in the composition is ≤ 1 ppm, even more preferably ≤ 0.1 ppm, and most preferably ≤ 0.01 ppm.

[0080] The composition is substantially free of phosphoric acid or its salts. Specifically, it is free of phosphates, such as organophosphates or alkali metal phosphates, such as potassium dihydrogen phosphate or sodium dihydrogen phosphate. Preferably, the composition contains ≤ 1 ppm of phosphoric acid or its salts. Phosphoric acid or its salts can combine with metals to form undesirable salts with low water solubility. Therefore, their presence may necessitate one or more additional filtration steps, leading to increased process costs.

[0081] The dielectric polishing composition of the present invention comprises components (A), (B), (C), (D), (E) and water, and optionally additional components as described below.

[0082] (A) Surface-modified colloidal silica particles

[0083] According to the invention claimed herein, the composition comprises negatively charged groups on the surface of the particles, wherein the surface-modified colloidal silica particles have a negative charge, a particle size of 60 nm to 200 nm, and a zeta potential of < -35 mV at a pH range of ≥ 2.0 to ≤ 6.0.

[0084] Well-known silica-selective compositions typically use cerium dioxide; however, it has been noted that the abrasive results in an unacceptably dull finish. Similar undesirable observations have been observed when fumed silica is used.

[0085] Preferably, the surface-modified silica particles have a zeta potential of < -35 mV, more preferably < -36 mV, even more preferably < -37 mV, and most preferably < -38 mV at a pH range of ≥ 2.0 to ≤ 6.0.

[0086] Preferably, the surface-modified silica particles have a zeta potential of > -50 mV, more preferably > -45 mV, and most preferably > -40 mV at a pH range of ≥ 2.0 to ≤ 6.0.

[0087] Preferably, the surface-modified silica particles have a zeta potential of -50 mV to -35 mV, more preferably -40 mV to -35 mV, even more preferably -45 mV to -35 mV, and most preferably -39 mV to -35 mV at a pH range of ≥ 2.0 to ≤ 6.0.

[0088] Surface-modified silica particles are preferably amorphous and non-agglomerated, and thus typically exist as discrete spheres that are not cross-linked to each other and contain hydroxyl groups on their surface. Surface-modified colloidal silica particles can be obtained by methods known in the art, such as ion exchange of silicates or by sol-gel techniques (e.g., hydrolysis or condensation of metal alkoxides, or sol-gel of precipitated hydrated silica, etc.).

[0089] Silica particles are known to be stabilized by a permanent charge on their surface, preventing agglomeration and ensuring colloidal stability. The charge can be positive or negative. Defects observed on the substrate surface during polishing due to the use of positively charged (or cationic) silica particles (see reference) Figure 2 b), therefore, negative charge is considered essential. This is described in Figure 2 In the defect-free surface described in section a, the substrate is planarized using a composition containing negatively charged (or anionic) silica particles. The charge on the surface is represented by the zeta potential. The zeta potential of the silica particles (unfunctionalized) depends on the pH value of the aqueous medium (reference). Figure 1 At pH above 8, the zeta potential is equal to or below -35 mV, low enough to ensure colloidal stability. Unbound by theory, it is believed that at acidic pH levels (e.g., pH 2–6), the surface charge decreases due to the interaction of silica with protons in the medium (the zeta potential is typically, for example, between +10 and -10 mV). A typical correlation between zeta potential and pH can be found in the literature (Esumi et al., Bull. Chem. Soc. Jpn. [Bulletin of the Chemical Society of Japan], Vol. 61, 1988). Once shear forces (e.g., through filtration or polishing) are present, the low surface charge can lead to agglomeration.

[0090] The zeta potential can be affected by the presence of additives. However, as will be readily understood by those skilled in the art, one or more of the mentioned components, which have negligible or no effect on the surface charge of the particles, may not have a significant effect on the zeta potential of particle (A), and therefore, a zeta potential of < -35 mV can still be achieved despite their presence during the measurement. Preferably, the zeta potential measurements for component (A) mentioned herein are performed in the absence of other components, i.e., when measured alone or in the substantially absence of other components (B) to (E), the surface-modified silica particles (A) have a zeta potential of < -35 mV. Figure 1-4 The measurements outlined herein were performed in the absence of other components.

[0091] Preferably, the surface-modified colloidal silica particles (A) having a negative zeta potential of < -35 mV at a pH range of ≥ 2.0 to ≤ 6.0 are silica particles modified with metallized anions or partially modified with sulfonic acid.

[0092] As explained in WO 2006 / 028759 A2, the term "modified with metallized ions and anions" as used herein specifically refers to silica particles in which the metallized ions (i.e., M(OH)4) are modified. - It binds to the surface of silica particles, replacing Si(OH)4 sites and generating a permanent negative charge.

[0093] Preferably, the surface-modified colloidal silica particles (A) having a negative zeta potential of < -35 mV at a pH range of ≥ 2.0 to ≤ 6.0 are silica particles modified with metallized anions. More preferably, the metallized ions are selected from aluminate, stannate, zincate, or leadate.

[0094] Even more preferably, the surface-modified colloidal silica particles (A) having a negative zeta potential of < -35 mV at a pH range of ≥ 2.0 to ≤ 6.0 are silica particles modified with aluminate anions. Such surface-modified colloidal silica particles are disclosed, for example, in WO 2006 / 7028759 A2.

[0095] More preferably, the surface-modified colloidal silica particles of component (A) having a negative zeta potential of < -35 mV at a pH range of ≥ 2.0 to ≤ 6.0 are silica particles modified with sulfonic acid anions. For example, sulfonic acid-modified aqueous anionic silica sols that are highly stable under acidic conditions are disclosed in WO2010734542 A1. In this document, sulfonic acid-modified aqueous anionic silica sols are obtained by a method in which a silane coupling agent having a functional group that can be chemically converted to a sulfonic acid group is chemisorbed onto colloidal silica, and then the functional group is converted to a sulfonic acid group. The preferred type of silica dispersion for this type of chemical reaction is having a similar Figure 1The zeta potential function of silica dispersions (unmodified silica particles) indicates that the charge on the particle surface is low under acidic conditions. This is also considered an indication of a clean silica surface, and silanes can readily react with groups on the silica surface. If the charge on the silica particles is already high (e.g., -36 or -50 mV) before reacting with a silane coupling agent under acidic conditions (e.g., pH 2–3), it is interpreted as an indication that the silica surface is not clean and has been modified. The silane coupling agent may not adequately cover the surface, and the surface charge may remain low subsequently after the reaction and conversion. Surface-modified particle dispersions with a zeta potential of, for example, -23 mV (e.g., pH 2–6) may have low colloidal stability. This means that the dispersion may be easily destabilized by processes such as filtration or CMP, which involve shear forces. In this case, filtered silica dispersions measured by DLS methods, such as with a Malvern Zetasizer ZSP, will provide a signal with high variation (see reference). Figure 3 This cannot be easily interpreted as average particle size. Other methods, such as sedimentation, must be used to evaluate colloidal stability. On the other hand, it is noted that silica particles modified with sulfonic acid anions produce a stable DLS signal that is easily measurable (see reference). Figure 4 ).

[0096] Preferably, the concentration of the surface-modified colloidal silica particles (A) is in the range of ≥3.2 wt.% to ≤13.0 wt.% based on the total weight of the composition. The concentration of the surface-modified colloidal silica particles (A) is preferably no greater than 13.0 wt.%, more preferably no greater than 10.0 wt.%, particularly no greater than 9.5 wt.%, even more preferably no greater than 9.0 wt.%, more preferably no greater than 8.5 wt.%, even more preferably no greater than 8.0 wt.%, for example no greater than 7.5 wt.%. It has been observed that a particle concentration greater than 10 wt.% leads to colloidal instability in the composition. Based on the total weight of the composition, the concentration of the surface-modified colloidal silica particles (A) is preferably at least 3.2 wt.%, more preferably at least 3.5 wt.%, even more preferably at least 3.8 wt.%, particularly at least 4.0 wt.%, even more preferably at least 4.1 wt.%, still more preferably at least 4.2 wt.%, more preferably at least 4.3 wt.%, even more preferably at least 4.5 wt.%, still more preferably at least 4.8 wt.%, and most preferably at least 5.2 wt.%. Particle concentrations below 3.2 wt.% are observed to result in low dielectric removal selectivity, i.e., a low silica to tungsten removal rate ratio. Based on the total weight of the composition, the concentration of the surface-modified colloidal silica particles (A) is more preferably in the range of ≥ 4.5 wt.% to ≤ 8.5 wt.%.

[0097] Surface-modified colloidal silica particles (A) can preferably be included in the composition in various particle size distributions. The particle size distribution of the surface-modified colloidal silica particles (A) can be unimodal or multimodal. In the case of a multimodal particle size distribution, a bimodal particle size distribution is generally preferred. For the purposes of the invention claimed herein, a unimodal particle size distribution is preferred for surface-modified colloidal silica particles (A).

[0098] According to the invention claimed herein, the average particle size of the surface-modified colloidal silica particles (A), as determined by dynamic light scattering technology, is in the range of 60 nm to 200 nm. The mean or average particle size of the surface-modified colloidal silica particles (A) can vary over a wide range. The average particle size of the surface-modified colloidal silica particles (A) is preferably in the range of ≥ 60 nm to ≤ 190 nm, more preferably in the range of ≥ 60 nm to ≤ 180 nm, more preferably in the range of ≥ 62 nm to ≤ 150 nm, more preferably in the range of ≥ 65 nm to ≤ 140 nm, particularly preferably in the range of ≥ 68 nm to ≤ 130 nm, and particularly most preferably in the range of ≥ 70 nm to ≤ 120 nm. In each case, the particle size is measured using dynamic light scattering techniques with instruments such as the Zetasizer ZSP or High Performance Particle Size Analyzer (HPPS) or Horiba LB550 from Malvern Instruments, Ltd.

[0099] Surface-modified colloidal silica particles (A) can preferably have various shapes. Therefore, particles (A) can preferably have one or essentially only one type of shape. However, particles (A) may also have different shapes. For example, two different types of particles (A) can exist. For example, (A) can have the shape of an agglomerate, a cube, a cube with a beveled edge, an octahedron, an icosahedron, a cocoon, a nodule, or a sphere, with or without protrusions or depressions.

[0100] Preferably, the surface-modified colloidal silica particles (A) are spherical, cocoon-shaped, or a mixture of spherical and cocoon-shaped particles. The spherical particles may or may not have protrusions or depressions. The cocoon-shaped particles may or may not have protrusions or depressions. The cocoon-shaped particles are preferably particles with a minor axis of ≥ 10 nm to ≤ 200 nm, and preferably a major axis / minor axis ratio of ≥ 1.4 to ≤ 2.2, more preferably ≥ 1.6 to ≤ 2.0. Preferably, they have an average shape factor of ≥ 0.7 to ≤ 0.97, more preferably ≥ 0.77 to ≤ 0.92, an average sphericity of ≥ 0.4 to ≤ 0.9, more preferably ≥ 0.5 to ≤ 0.7, and an average equivalent circular diameter of preferably ≥ 41 nm to ≤ 66 nm, more preferably ≥ 48 nm to ≤ 60 nm, determined in each case by transmission electron microscopy and scanning electron microscopy.

[0101] Most preferably, the surface-modified colloidal silica particles (A) are spherical or substantially spherical. The ratio of the major axis to the minor axis of the spherical or substantially spherical particles is ≥ 0.9.

[0102] For the purposes of the invention claimed herein, the determination of the shape factor, sphericity, and equivalent circle diameter of the cocoon-shaped particles is explained below. The shape factor provides information about the shape and indentation of an individual particle and can be calculated according to the following formula:

[0103] Shape factor = 4π (area / perimeter²)

[0104] The shape factor of a spherical particle without indentations is 1. The shape factor decreases as the number of indentations increases. Sphericity provides information about the elongation of a single particle using moments about the mean, and can be calculated using the following formula, where M is the centroid of the corresponding particle:

[0105] Sphericity = (Mxx - Myy) - [4 Mxy² + (Myy - Mxx)²]⁰.⁵ / (Mxx - Myy) + [4 Mxy² + (Myy - Mxx)²]⁰.⁵

[0106] Elongation = (1 / sphericity)^0.5

[0107] in

[0108] Mxx = Σ (average of xx) 2 / N

[0109] Myy = Σ (average of yy) 2 / N

[0110] Mxy = Σ [(xx average)] (yy average)] / N

[0111] N is the number of pixels that form the corresponding particle image.

[0112] x, y pixel coordinates

[0113] x is the average of the x-coordinates of the N pixels that form the particle image.

[0114] The average y-coordinate of the N pixels forming the particle image.

[0115] The sphericity of spherical particles is 1. The sphericity value decreases as the particle elongates. The equivalent circle diameter (ECD) of a single non-circular particle provides information about the diameter of a circle with the same area as the corresponding non-circular particle. The mean shape factor, mean sphericity, and mean ECD are the arithmetic mean of the corresponding properties related to the number of particles analyzed.

[0116] For the purposes of the invention claimed herein, the procedure for particle shape characterization is as follows: An aqueous cocoon-shaped silica particle dispersion having a solids content of 20 wt.% was dispersed on a carbon foil and dried. The dried dispersion was analyzed using energy-filtered transmission electron microscopy (EF-TEM) (120 kV) and scanning electron microscopy secondary electron imaging (SEM-SE) (5 kV). EF-TEM images with a resolution of 2 kΩ, 16 bits, and 0.6851 nm / pixel were used for analysis. After noise suppression, the images were binary-coded using a threshold. The particles were then manually separated. Overly covered and edge particles were distinguished and not used for analysis. ECD, shape factor, and sphericity, as defined previously, were calculated and statistically classified.

[0117] (B) Corrosion Inhibitor

[0118] According to the invention claimed herein, the composition comprises at least one corrosion inhibitor selected from at least one guanidine derivative.

[0119] As can be observed from Table 1 below, corrosion inhibitors selected from at least one guanidine derivative ensure high dielectric selectivity and an acceptable dielectric to tungsten removal rate ratio.

[0120] Preferably, the at least one guanidine derivative is selected from butylguanidine, phenformin, guanine, chloroguanidine hydrochloride, 2-guanidinylbenzimidazole, polyhexamethylene biguanide hydrochloride, polyaminopropyl biguanide, chlorhexidine, or chlorhexidine salt.

[0121] More preferably, the guanidine derivative is selected from chlorhexidine or chlorhexidine salts. Chlorhexidine or its salts are known to degrade into chemical subclasses over long periods; however, it is noted that the degradation process itself or the presence of degradation products in the composition has little or no effect on the CMP activity outlined herein. The concentration of the degradation products varies with conditions (temperature / pressure, etc.). Some possible degradation products are listed below in Table II-1 on page 19 of Zhixin Zong's paper entitled "Studies on the mechanisms of solid state and solution instability of drugs." For those skilled in the art, manipulating the concentration of degradation products and / or their concentrations to enhance activity is considered routine practice.

[0122]

[0123] Another suitable guanidine derivative is alixidine (N 1 N 1′ -(hexane-1,6-diyl)bis[N] 3[-(2-Ethylhexyl)iminodiacarboxamide]

[0124]

[0125] Preferably, chlorhexidine or chlorhexidine salts include the degradation products listed above.

[0126] Preferably, the corrosion inhibitor (B) is chlorhexidine.

[0127] Preferably, the corrosion inhibitor (B) is selected from chlorhexidine salts.

[0128] More preferably, the chlorhexidine salt is selected from the group consisting of: chlorhexidine gluconate, chlorhexidine digluconate, chlorhexidine hydrochloride, chlorhexidine dihydrochloride, chlorhexidine acetate, chlorhexidine diacetate, chlorhexidine hexametaphosphate, chlorhexidine metaphosphate, and chlorhexidine trimetaphosphate.

[0129] Most preferably, the corrosion inhibitor is selected from the group consisting of chlorhexidine, chlorhexidine gluconate, and chlorhexidine disodium gluconate.

[0130] Preferably, the corrosion inhibitor (B) is present in an amount ranging from ≥ 0.001 wt.% to ≤ 0.05 wt.% based on the total weight of the composition. More preferably, the corrosion inhibitor (B) is present in an amount not greater than 0.04 wt.%, and most preferably not greater than 0.03 wt.% based on the total weight of the composition. Based on the total weight of the composition, the amount of (B) is preferably at least 0.002 wt.%, and more preferably at least 0.003 wt.%. Based on the total weight of the composition, the concentration of the corrosion inhibitor (B) is more preferably in the range of ≥ 0.003 wt.% to ≤ 0.03 wt.%.

[0131] (C) Iron (III) oxidizing agent

[0132] According to the invention claimed herein, the composition comprises at least one iron (III) oxidizing agent (C).

[0133] As can be observed from Table 1 below, iron (III) oxidant (C) oxidizes the substrate to be polished or one of its layers, thereby ensuring a chemical contribution to the removal rate and high surface quality.

[0134] Preferably, the iron (III) oxidizing agent (C) is selected from iron (III) salts or compounds of nitric acid, sulfuric acid, hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, acetic acid, o-phosphoethanolamine, phosphonic acid, or mixtures thereof.

[0135] More preferably, the iron (III) oxidizing agent (C) is selected from ferric nitrate (III) or its hydrate. Even more preferably, the iron (III) oxidizing agent (C) is ferric nitrate (III).

[0136] Preferably, the concentration of iron(III) oxidant (C) is in the range of ≥ 0.003 wt.% to ≤ 0.1 wt.% based on the total weight of the composition. More preferably, iron(III) oxidant (C) is present in an amount not greater than 0.08 wt.%, even more preferably not greater than 0.07 wt.%, most preferably not greater than 0.05 wt.%, and most preferably not greater than 0.03 wt.% based on the total weight of the composition. The amount of (C) is preferably at least 0.0035 wt.%, more preferably at least 0.004 wt.%, and most preferably at least 0.0045 wt.% based on the total weight of the composition. When the amount of (C) is less than < 0.003 wt%, an undesirable high silica (dielectric) to tungsten MRR ratio is noted. On the other hand, when the amount of (C) is > 0.1 wt.%, an undesirable low dielectric selectivity (low dielectric to tungsten removal rate ratio) is observed. Based on the total weight of the composition, the concentration of iron(III) oxidant (C) is more preferably in the range of ≥ 0.0045 wt.% to ≤ 0.03 wt.%, and most preferably in the range of ≥ 0.0048 wt.% to ≤ 0.02 wt.%.

[0137] (D) Buffer

[0138] According to the invention claimed herein, the composition comprises at least one buffer selected from at least one acidic amino acid having an isoelectric point (pI) of ≤ 5.0.

[0139] As can be observed from Table 1 below, the buffer (D) specifically prevents undesirable dish-shaped depressions in the dielectric layer during chemical mechanical polishing, while allowing the pH and high silica (dielectric) removal rate to be maintained appropriately.

[0140] Chemically, buffers consist of a weak acid and its conjugate base or a weak base and its conjugate acid. For example, glutamic acid (a strong base) with a -NH2 group and its protonated form (with a -NH3 group) are examples. +The groups (or conjugated acid forms) combine in solution to provide a buffer (as is the case when present in an aqueous composition of the claimed invention with a pH range of ≥ 2.0 to ≤ 6.0). Note that amino acids have a buffer region located within a range of ±1 pH unit of their pKa value. For the claimed invention, this buffer region will be near the pKa1 of the corresponding amino acid (glutamic acid and aspartic acid have pKa1s of approximately 2.19 and 1.88, respectively; see: Carey and Giuliano (2011) Amino acids, peptides and proteins. Organic Chemistry, 8th edition, 25, 1126 McGraw Hill, ISBN-13: 978-0077354770).

[0141] For the acidic amino acids mentioned herein, the isoelectric point (pI) can be conveniently calculated by averaging the pKa values ​​of the two carboxylic acid groups (the two with the lowest acidity pKa values). For example, if the pKa values ​​of the carboxylic acid groups of glutamic acid are 2.19 and 4.25, the calculated pI is 3.22. Similarly, the pI of aspartic acid is 2.77. Furthermore, the pKa value can be obtained by titrating the groups with a suitable acid / base. The buffer (D) is an acidic amino acid having an isoelectric point (pI) of ≤ 5.0, more preferably ≤ 4.5, even more preferably ≤ 4.0, and most preferably ≤ 3.5.

[0142] Preferably, the buffer (D) is an acidic amino acid selected from aspartic acid or glutamic acid. Most preferably, the buffer (D) is aspartic acid.

[0143] Amino acids are known to exist as L or R optical isomers, with the L form being biologically relevant and common. For the purposes of the invention claimed herein, both isomers are functionally similar and both can be used; however, for economic reasons, the L form may be preferred. Preferably, the acidic amino acid is selected from either the L or R isomer.

[0144] Preferably, the concentration of buffer (D) is in the range of ≥ 0.1 wt.% to ≤ 0.78 wt.% based on the total weight of the composition. More preferably, buffer (D) is present in an amount not greater than 0.75 wt.%, even more preferably not greater than 0.73 wt.%, and most preferably not greater than 0.7 wt.% based on the total weight of the composition. The presence of (D) in an amount > 0.78 wt.% results in an undesirable increase in silica (dielectric) disc-shaped depressions. On the other hand, the presence of (D) in an amount < 0.1 wt.% results in insufficient pH stability. The amount of (D) based on the total weight of the composition is preferably at least 0.15 wt.%, more preferably at least 0.2 wt.%, even more preferably at least 0.25 wt.%, and most preferably at least 0.28 wt.%. Based on the total weight of the composition, the concentration of buffer (D) is more preferably in the range of ≥ 0.15 wt.% to ≤ 0.75 wt.%, and most preferably in the range of ≥ 0.25 wt.% to ≤ 0.73 wt.%.

[0145] In a preferred embodiment, the buffer (D) is selected from aspartic acid or glutamic acid and is present in an amount of ≥ 0.15 wt.% to ≤ 0.75 wt.% based on the total weight of the composition.

[0146] In another preferred embodiment, the buffer (D) is aspartic acid and is present in an amount of ≥ 0.15 wt.% to ≤ 0.75 wt.% based on the total weight of the composition.

[0147] (E) Stabilizer

[0148] According to the invention claimed herein, the composition comprises at least one stabilizer (E).

[0149] Unrestricted by theory, agglomeration is expected to be very common when incompatible components such as silica particles and iron (III) salts are used. However, as can be observed from Table 1 below, stabilizer (E) ensures colloidal stability.

[0150] Preferably, the at least one stabilizer (E) is selected from acetic acid, acetylacetone, o-phosphoethanolamine, phosphonic acid, alendronic acid, acetic acid, phthalic acid, citric acid, adipic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, oxalic acid, maleic acid, gluconic acid, mucoconic acid, ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, N,N-bis(carboxymethyl)alanine, hypozoxytriacetic acid, diethylenetriaminepentaacetic acid, bis(salicylyl)ethylenediamine, aminotris(methylenephosphonic acid), diethylenetriaminepenta(methylphosphonic acid), ethylenediaminetetra(methylenephosphonic acid), or mixtures thereof.

[0151] More preferably, the at least one stabilizer (E) is selected from phthalic acid, citric acid, adipic acid, oxalic acid, succinic acid, glutaric acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, oxalic acid, maleic acid, gluconic acid, mucoconic acid, ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, N,N-bis(carboxymethyl)alanine, hypozoxytriacetic acid, diethylenetriaminepentaacetic acid, bis(salicylyl)ethylenediamine, aminotris(methylenephosphonic acid), diethylenetriaminepenta(methylphosphonic acid), ethylenediaminetetra(methylenephosphonic acid), or mixtures thereof.

[0152] Even more preferably, the at least one stabilizer (E) is selected from ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, N,N-bis(carboxymethyl)alanine, hypozinotriacetic acid, diethylenetriaminepentaacetic acid, bis(salicylyl)ethylenediamine, aminotris(methylenephosphonic acid), diethylenetriaminepenta(methylphosphonic acid), ethylenediaminetetra(methylenephosphonic acid), or mixtures thereof.

[0153] Most preferably, the at least one stabilizer (E) is ethylenediaminetetraacetic acid.

[0154] Preferably, the concentration of stabilizer (E) is in the range of ≥ 0.005 wt.% to ≤ 0.15 wt.% based on the total weight of the composition. More preferably, stabilizer (E) is present in an amount not greater than 0.1 wt.%, even more preferably not greater than 0.08 wt.%, and most preferably not greater than 0.03 wt.% based on the total weight of the composition. The amount of (E) is preferably at least 0.0055 wt.%, more preferably at least 0.006 wt.%, and most preferably at least 0.008 wt.% based on the total weight of the composition. The concentration of stabilizer (E) is more preferably in the range of ≥ 0.0055 wt.% to ≤ 0.08 wt.%, and most preferably in the range of ≥ 0.008 wt.% to ≤ 0.03 wt.% based on the total weight of the composition.

[0155] (F) Aqueous medium

[0156] According to the invention claimed herein, the composition comprises an aqueous medium (F). The aqueous medium (F) may be a single type of aqueous medium or a mixture of different types of aqueous media.

[0157] The aqueous medium (F) can preferably be any medium containing water. Preferably, the aqueous medium (F) is a mixture of water and an organic solvent miscible with water. Representative examples of organic solvents include, but are not limited to, C1 to C3 alcohols, alkylene glycols, and alkylene glycol derivatives.

[0158] More preferably, the aqueous medium (F) is water. In a preferred embodiment of the invention claimed herein, the aqueous medium (F) is deionized water.

[0159] For the purposes of the invention claimed herein, if the total amount of the components other than (F) is y wt.% of the composition, then the amount of (F) is (100-y) wt.% of the composition.

[0160] Based on the total weight of the composition, the amount of aqueous medium (F) in the composition is preferably not greater than 99.9 wt.%, more preferably not greater than 99.6 wt.%, most preferably not greater than 99 wt.%, particularly preferably not greater than 98 wt.%, particularly not greater than 97 wt.%, for example not greater than 95 wt.%. Based on the total weight of the composition, the amount of aqueous medium (F) in the composition is preferably at least 65 wt.%, more preferably at least 75 wt.%, most preferably at least 85 wt.%, particularly preferably at least 88 wt.%, particularly at least 90 wt.%, for example at least 92.5 wt.%.

[0161] The properties of the composition may depend on the pH of the corresponding composition. According to the invention claimed herein, the pH of the composition is in the range of ≥ 2.0 to ≤ 4.3. Preferably, the pH of the composition is ≤ 4.2, more preferably ≤ 4.1, most preferably ≤ 4.05, particularly preferably ≤ 4.0, and particularly most preferably ≤ 3.5. The pH of the composition is preferably ≥ 2.1, more preferably ≥ 2.3, most preferably ≥ 2.5, particularly preferably ≥ 2.6, and particularly most preferably ≥ 2.8. The pH of the composition is preferably in the range of ≥ 2.1 to ≤ 4.2, preferably ≥ 2.3 to ≤ 4.1, more preferably ≥ 2.5 to ≤ 4.0, and most preferably ≥ 2.8 to ≤ 3.5.

[0162] Preferably, the composition further comprises an additive selected from the group consisting of pH adjusters, oxidants, wetting agents, dispersants, biocides, or mixtures thereof. More preferably, the at least one additive is different from components (A), (B), (C), (D), (E), and (F), and may be optionally added in addition to said components.

[0163] Preferably, the at least one pH adjuster is selected from the group consisting of: inorganic acids, carboxylic acids, amine bases, and ammonium hydroxide (including tetraalkylammonium hydroxide). Preferably, the at least one pH adjuster is selected from the group consisting of nitric acid, sulfuric acid, and ammonia. More preferably, the pH adjuster is nitric acid.

[0164] Based on the total weight of the composition, the amount of the at least one pH adjuster is preferably no more than 10 wt.%, more preferably no more than 2 wt.%, most preferably no more than 0.5 wt.%, particularly no more than 0.1 wt.%, for example no more than 0.05 wt.%. Based on the total weight of the composition, the amount of the at least one pH adjuster is preferably at least 0.0005 wt.%, more preferably at least 0.005 wt.%, most preferably at least 0.025 wt.%, particularly at least 0.1 wt.%, for example at least 0.4 wt.%.

[0165] Preferably, the composition of the invention claimed herein may further contain at least one oxidizing agent.

[0166] Preferably, the at least one oxidizing agent is selected from the group consisting of: organic peroxides, inorganic peroxides, nitrates, persulfates, iodates, periodic acid, periodate, permanganate, perchloric acid, perchlorate, bromic acid, and bromate. The oxidizing agent may optionally be present in addition to iron (III) oxidizing agents.

[0167] More preferably, the at least one oxidant is hydrogen peroxide.

[0168] Preferably, the at least one oxidant is present in an amount ranging from ≥ 0.01 wt.% to ≤ 1.0 wt.% based on the total weight of the composition.

[0169] Preferably, the concentration of the at least one oxidant is no more than 5.0 wt.%, even more preferably no more than 2.0 wt.%, even more preferably no more than 1.0 wt.%, even more preferably no more than 0.8 wt.%, and most preferably no more than 0.5 wt.%, based on the total weight of the composition in each case. The concentration of the at least one oxidant is preferably at least 0.01 wt.%, more preferably at least 0.05 wt.%, and most preferably at least 0.1 wt.%, based on the total weight of the composition in each case.

[0170] More preferably, the concentration of hydrogen peroxide as an oxidant is ≥ 0.01 wt.% to ≤ 1.0 wt.%, even more preferably ≥ 0.05 wt.% to ≤ 1.0 wt.%, most preferably ≥ 0.05 wt.% to ≤ 0.5 wt.%, particularly preferably ≥ 0.01 wt.% to ≤ 0.1 wt.%, based on the total weight of the composition in each case.

[0171] Methods for preparing compositions for chemical mechanical polishing are generally known. The compositions of the invention claimed herein can be prepared using these methods. This can be done by dispersing or dissolving the components (A), (B), (C), (D), and (E) described above in an aqueous medium (F), preferably water, and optionally by adjusting the pH value via the addition of an acid and / or a base (pH adjuster). For this purpose, conventional and standard mixing methods and equipment, such as stirred tanks, high-shear impellers, ultrasonic mixers, homogenizer nozzles, or countercurrent mixers, can be used.

[0172] Preferred embodiments of the invention claimed herein relate to a composition comprising the following components:

[0173] (A) Surface-modified colloidal silica particles, wherein the surface of these particles contains negatively charged groups, wherein these surface-modified colloidal silica particles...

[0174] The particles have a negative charge.

[0175] Particle sizes ranging from 60 nm to 200 nm, and

[0176] ζ potential < -35 mV at pH ≥ 2.0 to ≤ 6.0;

[0177] (B) At least one corrosion inhibitor selected from at least one guanidine derivative;

[0178] (C) At least one iron (III) oxidizing agent;

[0179] (D) At least one buffer selected from at least one acidic amino acid having an isoelectric point (pI) of ≤ 5.0;

[0180] (E) At least one stabilizer selected from: ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, N,N-bis(carboxymethyl)alanine, hypozinotriacetic acid, diethylenetriaminepentaacetic acid, bis(salicylene)ethylenediamine, aminotris(methylenephosphonic acid), diethylenetriaminepenta(methylphosphonic acid), ethylenediaminetetra(methylenephosphonic acid), or mixtures thereof; and

[0181] (F) Aqueous medium,

[0182] The pH of the composition is in the range of ≥ 2.0 to ≤ 4.3, and

[0183] The composition contains ≤ 1 ppm of polyacrylamide.

[0184] Another preferred embodiment of the invention claimed herein relates to a composition comprising the following components:

[0185] (A) Surface-modified colloidal silica particles, wherein the surface of these particles contains negatively charged groups, wherein these surface-modified colloidal silica particles...

[0186] The particles have a negative charge.

[0187] Particle size from 60 nm to 200 nm,

[0188] A zeta potential of < -35 mV at pH values ​​≥ 2.0 to ≤ 6.0, and

[0189] It has a concentration based on the total weight of the composition in the range of ≥ 3.2 wt.% to ≤ 13.0 wt.%.

[0190] (B) At least one corrosion inhibitor selected from at least one guanidine derivative and having a concentration in the range of ≥ 0.001 wt.% to ≤ 0.05 wt.% based on the total weight of the composition;

[0191] (C) At least one iron (III) oxidizing agent, which is in the range of ≥ 0.003 wt.% to ≤ 0.1 wt.% based on the total weight of the composition;

[0192] (D) At least one buffer selected from at least one acidic amino acid having an isoelectric point (pI) of ≤ 5.0 and having a concentration in the range of ≥ 0.1 wt.% to ≤ 0.78 wt.% based on the total weight of the composition;

[0193] (E) At least one stabilizer selected from ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, N,N-bis(carboxymethyl)alanine, hypozinotriacetic acid, diethylenetriaminepentaacetic acid, bis(salicylene)ethylenediamine, aminotris(methylenephosphonic acid), diethylenetriaminepenta(methylphosphonic acid), ethylenediaminetetra(methylenephosphonic acid), or mixtures thereof and having a concentration in the range of ≥ 0.005 wt.% to ≤ 0.15 wt.% based on the total weight of the composition; and

[0194] (F) Aqueous medium,

[0195] The pH of the composition is in the range of ≥ 2.0 to ≤ 4.3, and

[0196] The composition contains ≤ 1 ppm of polyacrylamide.

[0197] Another preferred embodiment of the invention claimed herein relates to a composition comprising the following components:

[0198] (A) Surface-modified colloidal silica particles, wherein the surface of these particles contains negatively charged groups, wherein these surface-modified colloidal silica particles...

[0199] The particles have a negative charge.

[0200] Particle size from 60 nm to 200 nm,

[0201] A zeta potential of < -35 mV at pH values ​​≥ 2.0 to ≤ 6.0, and

[0202] It has a concentration based on the total weight of the composition in the range of ≥ 3.2 wt.% to ≤ 13.0 wt.%.

[0203] (B) At least one corrosion inhibitor selected from at least one guanidine derivative and having a concentration in the range of ≥ 0.001 wt.% to ≤ 0.05 wt.% based on the total weight of the composition;

[0204] (C) At least one iron (III) oxidizing agent, which is in the range of ≥ 0.003 wt.% to ≤ 0.1 wt.% based on the total weight of the composition;

[0205] (D) At least one buffer selected from at least one acidic amino acid having an isoelectric point (pI) of ≤ 5.0 and having a concentration in the range of ≥ 0.1 wt.% to ≤ 0.78 wt.% based on the total weight of the composition;

[0206] (E) At least one stabilizer selected from ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, N,N-bis(carboxymethyl)alanine, hypozinotriacetic acid, diethylenetriaminepentaacetic acid, bis(salicylene)ethylenediamine, aminotris(methylenephosphonic acid), diethylenetriaminepenta(methylphosphonic acid), ethylenediaminetetra(methylenephosphonic acid), or mixtures thereof and having a concentration in the range of ≥ 0.005 wt.% to ≤ 0.15 wt.% based on the total weight of the composition; and

[0207] (F) Aqueous medium,

[0208] The pH of the composition is in the range of ≥ 2.0 to ≤ 4.3.

[0209] The composition contains ≤ 1 ppm of polyacrylamide, and

[0210] The composition has an alkali metal content of ≤ 1 ppm.

[0211] Another preferred embodiment of the invention claimed herein relates to a composition comprising the following components:

[0212] (A) Surface-modified colloidal silica particles, wherein the surface of these particles contains negatively charged groups, wherein these surface-modified colloidal silica particles...

[0213] The particles have a negative charge.

[0214] Particle size from 60 nm to 200 nm,

[0215] A zeta potential of < -35 mV at pH values ​​≥ 2.5 to ≤ 6.0, and

[0216] Concentrations in the range of ≥ 0.3 wt.% to ≤ 7.0 wt.% based on the total weight of the composition;

[0217] (B) At least one corrosion inhibitor selected from at least one guanidine derivative and having a concentration in the range of ≥ 0.003 wt.% to ≤ 0.03 wt.% based on the total weight of the composition;

[0218] (C) At least one iron (III) oxidizing agent, which is in the range of ≥ 0.0048 wt.% to ≤0.02 wt.% based on the total weight of the composition;

[0219] (D) At least one buffer selected from at least one acidic amino acid having an isoelectric point (pI) of ≤ 5.0 and having a concentration in the range of ≥ 0.15 wt.% to ≤ 0.75 wt.% based on the total weight of the composition;

[0220] (E) At least one stabilizer selected from ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, N,N-bis(carboxymethyl)alanine, hypozinotriacetic acid, diethylenetriaminepentaacetic acid, bis(salicylene)ethylenediamine, aminotris(methylenephosphonic acid), diethylenetriaminepenta(methylphosphonic acid), ethylenediaminetetra(methylenephosphonic acid), or mixtures thereof and having a concentration in the range of ≥ 0.008 wt.% to ≤ 0.03 wt.% based on the total weight of the composition; and

[0221] (F) Aqueous medium,

[0222] The pH of the composition is in the range of ≥ 2.5 to ≤ 4.3, and

[0223] The composition contains ≤ 1 ppm of polyacrylamide.

[0224] Preferred embodiments of the invention claimed herein relate to a composition comprising the following components:

[0225] (A) Surface-modified colloidal silica particles, wherein the surface of these particles contains negatively charged groups, wherein these surface-modified colloidal silica particles...

[0226] The particles have a negative charge.

[0227] Particle size from 60 nm to 200 nm,

[0228] A zeta potential of < -35 mV at pH values ​​≥ 2.5 to ≤ 6.0, and

[0229] Concentrations in the range of ≥ 0.3 wt.% to ≤ 7.0 wt.% based on the total weight of the composition;

[0230] (B) At least one corrosion inhibitor selected from at least one of butylguanidine, phenformin, guanine, chloroguanidine hydrochloride, 2-guanidinobenzimidazole, polyhexamethylene biguanide hydrochloride, polyaminopropyl biguanide, chlorhexidine or chlorhexidine salt, preferably chlorhexidine salt or guanidine derivative of chlorhexidine salt and having a concentration in the range of ≥ 0.003 wt.% to ≤0.03 wt.% based on the total weight of the composition;

[0231] (C) At least one iron (III) oxidizing agent, which is in the range of ≥ 0.0048 wt.% to ≤0.02 wt.% based on the total weight of the composition;

[0232] At least one buffer (D) selected from aspartic acid or glutamic acid and having a concentration in the range of ≥ 0.15 wt.% to ≤ 0.75 wt.% based on the total weight of the composition;

[0233] (E) At least one stabilizer selected from ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, N,N-bis(carboxymethyl)alanine, hypozinotriacetic acid, diethylenetriaminepentaacetic acid, bis(salicylene)ethylenediamine, aminotris(methylenephosphonic acid), diethylenetriaminepenta(methylphosphonic acid), ethylenediaminetetra(methylenephosphonic acid), or mixtures thereof and having a concentration in the range of ≥ 0.008 wt.% to ≤ 0.03 wt.% based on the total weight of the composition; and

[0234] (F) Aqueous medium,

[0235] The pH of the composition is in the range of ≥ 2.5 to ≤ 4.3, and

[0236] The composition contains ≤ 1 ppm of polyacrylamide.

[0237] Method for manufacturing semiconductor devices

[0238] On the other hand, the invention claimed herein relates to a method for manufacturing a semiconductor device, the method comprising chemically and mechanically polishing a substrate (S) used in the semiconductor industry in the presence of a composition as described herein, the substrate (S) comprising...

[0239] (i) Tungsten and / or

[0240] (ii) Tungsten alloys; and

[0241] (iii) At least one dielectric layer selected from silicon, silicon oxide, silicon nitride, or low-k materials.

[0242] Preferably, the dielectric layer is selected from silicon oxide, silicon nitride, or a combination thereof.

[0243] Preferably, the ratio of the material removal rate (MRR) of silica to the material removal rate (MRR) of tungsten is <15.0, more preferably <14.5. More preferably, the ratio of the material removal rate (MRR) of silica to tungsten is in the range of 1.2:1 to 15:1. Even more preferably, the ratio of the material removal rate (MRR) of silica to tungsten is in the range of 1.5:1 to 14.9:1. More preferably, the ratio of the material removal rate (MRR) of silica to tungsten is in the range of 2.2:1 to 14.5:1. Even more preferably, the ratio of the material removal rate (MRR) of silica to tungsten is in the range of 2.3:1 to 14:1. Most preferably, the ratio of the material removal rate (MRR) of silica to the material removal rate (MRR) of tungsten is in the range of 2.5:1 to 13:1. Without being bound by theory, high selectivity of tungsten relative to TEOS / silica (low silica to tungsten ratio ≥ 15.0) may result in undesirable microscratches or surface roughness.

[0244] Preferably, the static etching rate (SER) of tungsten is < 30 ppb. More preferably, the static etching rate (SER) of tungsten is < 25 ppb. Even more preferably, the static etching rate (SER) of tungsten is < 23 ppb. Most preferably, the static etching rate (SER) of tungsten is < 22 ppb.

[0245] Preferably, the material removal rate (MRR) of silicon oxide is > 300 Å / min. More preferably, the material removal rate (MRR) of silicon oxide is > 350 Å / min. Even more preferably, the material removal rate (MRR) of silicon oxide is > 420 Å / min. Most preferably, the material removal rate (MRR) of silicon oxide is > 450 Å / min.

[0246] Preferably, the material removal rate (MRR) of tungsten is < 200 Å / min. More preferably, the material removal rate (MRR) of tungsten is < 180 Å / min. Most preferably, the material removal rate (MRR) of tungsten is < 130 Å / min.

[0247] There are no particular limitations on the semiconductor devices that can be manufactured by the methods claimed herein. A semiconductor device can be an electronic component comprising semiconductor materials, such as, for example, silicon, germanium, and group III-V materials. A semiconductor device can be a device manufactured as a single discrete device or as a device manufactured as an integrated circuit (IC), which consists of several devices fabricated and interconnected on a wafer. A semiconductor device can be a two-terminal device, such as a diode; a three-terminal device, such as a bipolar transistor; a four-terminal device, such as a Hall effect sensor; or a multi-terminal device. Preferably, the semiconductor device is a multi-terminal device. A multi-terminal device can be a logic device as an integrated circuit and a microprocessor, or a storage device as random access memory (RAM), read-only memory (ROM), and phase-change random access memory (PCRAM). Preferably, the semiconductor device is a multi-terminal logic device. In particular, the semiconductor device is an integrated circuit or a microprocessor.

[0248] Typically, in integrated circuits, tungsten (W) is used for M0 or M1 interconnects. Excess tungsten above the dielectric can be removed using known chemical mechanical polishing processes.

[0249] Typically, the tungsten / tungsten alloy can be produced or obtained in various ways, such as ALD, PVD, or CVD processes. Generally, the tungsten and / or tungsten alloy can be of any type, form, or shape. The tungsten and / or tungsten alloy preferably has a layered or overgrown shape. If the tungsten and / or tungsten alloy has a layered or overgrown shape, the tungsten and / or tungsten alloy content is preferably greater than 90% by weight of the corresponding layer and / or overgrown, more preferably greater than 95%, most preferably greater than 98%, particularly greater than 99%, for example greater than 99.9%. The tungsten and / or tungsten alloy preferably fills or grows in trenches or plugs between other substrates, more preferably in trenches or plugs of dielectric materials such as, for example, SiO2, silicon, low-k (BD1, BD2) or ultra-low-k materials, or other insulating and semiconductor materials used in the semiconductor industry. For example, in the intermediate process of through-silicon via (TSV), insulating materials (such as polymers, photoresists, and / or polyimides) can be used as insulating materials between wet etching and subsequent CMP process steps after the TSV is exposed from the back of the wafer due to their insulating / isolating properties.

[0250] use

[0251] On the other hand, the invention claimed herein relates to the use of the composition described herein for polishing a substrate (S) comprising: (i) tungsten and / or (ii) a tungsten alloy; and (iii) at least one dielectric layer.

[0252] Preferably, the at least one dielectric layer is selected from silicon, silicon oxide, silicon nitride, or a low-k material. More preferably, the dielectric layer comprises silicon oxide, silicon nitride, or a combination thereof.

[0253] Preferably, the composition is used in semiconductor manufacturing and its processes.

[0254] The invention claimed herein is illustrated in more detail with reference to the accompanying drawings.

[0255] Figure 1 The effect of pH on the zeta potential of surface-modified colloidal silica particles (i.e., component (A)) is shown, as measured by electrophoresis. Colloidal silica particles with two different particle sizes of 75 and 109 nm were investigated.

[0256] Figure 2 A surface image (obtained by SEM) of a substrate polished using the composition is depicted. A substrate polished with the composition according to the invention, containing anionic colloidal silica particles, is shown in [the image]. Figure 2 In a, the substrate polished with cationic colloidal silica particles is shown. Figure 2 b in.

[0257] Figure 3 The DLS measurements of filtered silica dispersions, measured using a Malvern Zetasizer ZSP, were depicted when the zeta potential of surface-modified colloidal silica particles was > -35 mV within a pH range of ≥ 2.0 to ≤ 4.5. These measurements indicate that the DLS method cannot record stable measurements when the zeta potential of surface-modified colloidal silica particles is > -35 mV within a pH range of ≥ 2.0 to ≤ 4.5. Measurements were performed at pH 2.8 with the zeta potential of the silica particles set to -23 mV using 0.1 M potassium chloride.

[0258] Figure 4 The DLS measurements of filtered silica dispersions, measured using Malvern Zetasizer ZSP, are depicted when the zeta potential of surface-modified colloidal silica particles is < -35 mV at pH values ​​ranging from ≥ 2.0 to ≤ 4.5.

[0259] The composition according to the invention claimed herein has at least one of the following advantages:

[0260] (1) The compositions and methods of the invention claimed herein demonstrate high selectivity for the removal of silicon oxide relative to tungsten.

[0261] (2) The compositions and methods of the invention claimed herein have shown improved performance in suppressing etching (especially etch of tungsten and cobalt) (as evidenced by the low SER values).

[0262] (3) The compositions of the invention claimed herein provide stable formulations or dispersions in which no phase separation or agglomeration occurs, especially under acidic conditions.

[0263] (4) The compositions of the invention claimed herein are permitted to have processability, such as compatibility with industrially relevant steps such as microfiltration.

[0264] (5) The method of the invention claimed herein is easy to apply and requires as few steps as possible.

[0265] (6) The compositions and methods of the invention claimed herein allow for good adjustability, thereby allowing for high silicon oxide (SiO2) removal rates while ensuring relatively comparable tungsten (W) removal rates.

[0266] (7) The composition of the invention claimed herein is intended to provide a suitable removal rate as mentioned above, while preventing undesirable surface defects and ensuring high surface quality.

[0267] (8) The compositions and methods of the invention claimed herein reduce undesirable dish-shaped depressions in the dielectric layer. Example

[0268] The following list of embodiments is provided to further illustrate this disclosure, but is not intended to limit this disclosure to the specific embodiments listed below.

[0269] 1. A dielectric polishing composition comprising

[0270] (A) Surface-modified colloidal silica particles, wherein the surface of these particles contains negatively charged groups, wherein these surface-modified colloidal silica particles...

[0271] The particles have a negative charge.

[0272] Particle sizes ranging from 60 nm to 200 nm, and

[0273] ζ potential ≤ -35 ​​mV at pH range ≥ 2.0 to ≤ 6.0;

[0274] (B) At least one corrosion inhibitor selected from at least one guanidine derivative;

[0275] (C) At least one iron (III) oxidizing agent;

[0276] (D) At least one buffer selected from at least one acidic amino acid having an isoelectric point (pI) of ≤ 5.0;

[0277] (E) at least one stabilizer; and

[0278] (F) Aqueous medium,

[0279] The pH of the composition is in the range of ≥ 2.0 to ≤ 4.3, and

[0280] The composition contains ≤ 1 ppm of polyacrylamide.

[0281] 2. The composition according to any one of the foregoing embodiments, wherein these surface-modified colloidal silica particles have a zeta potential of -35 mV to -50 mV at a pH range of ≥ 2.0 to ≤ 6.0.

[0282] 3. The composition according to any one of the foregoing embodiments, wherein the concentration of these surface-modified colloidal silica particles (A) is in the range of ≥ 3.2 wt.% to ≤ 13.0 wt.% based on the total weight of the composition.

[0283] 4. The composition according to any one of the foregoing embodiments, wherein the guanidine derivative is selected from butylguanidine, phenformin, guanine, chloroguanidine hydrochloride, 2-guanidinylbenzimidazole, polyhexamethylene biguanide hydrochloride, polyaminopropyl biguanide, chlorhexidine or chlorhexidine salt, preferably chlorhexidine or chlorhexidine salt.

[0284] 5. The composition according to any one of the foregoing embodiments, wherein the concentration of the corrosion inhibitor (B) is in the range of ≥ 0.001 wt.% to ≤ 0.05 wt.% based on the total weight of the composition.

[0285] 6. The composition according to any one of the foregoing embodiments, wherein the pH of the composition is in the range of ≥ 3.0 to ≤ 4.0.

[0286] 7. The composition according to any one of the foregoing embodiments, wherein the iron(III) oxidant (C) is selected from ferric nitrate(III) or its hydrate.

[0287] 8. The composition according to any one of the foregoing embodiments, wherein the concentration of the iron (III) oxidant (C) is in the range of ≥ 0.003 wt.% to ≤ 0.1 wt.% based on the total weight of the composition.

[0288] 9. The composition according to any one of the foregoing embodiments, wherein the buffer (D) is an acidic amino acid selected from aspartic acid or glutamic acid.

[0289] 10. The composition according to any one of the foregoing embodiments, wherein the concentration of the buffer (D) is in the range of ≥ 0.1 wt.% to ≤ 0.78 wt.% based on the total weight of the composition.

[0290] 11. The composition according to any one of the foregoing embodiments, wherein the stabilizer (E) is selected from acetic acid, acetylacetone, 0-phosphoethanolamine, phosphonic acid, alendronic acid, acetic acid, phthalic acid, citric acid, adipic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, oxalic acid, maleic acid, gluconic acid, mucoconic acid, ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, N,N-bis(carboxymethyl)alanine, hypozoxytriacetic acid, diethylenetriaminepentaacetic acid, bis(salicylyl)ethylenediamine, aminotris(methylenephosphonic acid), diethylenetriaminepenta(methylphosphonic acid), ethylenediaminetetra(methylenephosphonic acid), or mixtures thereof.

[0291] 12. The composition according to any one of the foregoing embodiments, wherein the concentration of the stabilizer (E) is in the range of ≥ 0.005 wt.% to ≤ 0.15 wt.% based on the total weight of the composition.

[0292] 13. The composition according to any one of the foregoing embodiments, wherein the composition has a potassium content of ≤10 ppm.

[0293] 14. The composition according to any one of the foregoing embodiments, wherein the composition further comprises an additive selected from: pH adjuster, oxidant, wetting agent, dispersant, biocide, or mixture thereof.

[0294] 15. The composition according to any one of the foregoing embodiments, wherein the composition is used for polishing a substrate (S), wherein the substrate (S) comprises: (i) tungsten and / or (ii) a tungsten alloy; and (iii) at least one dielectric layer selected from silicon, silicon oxide, silicon nitride, or a low-k material.

[0295] 16. A method for manufacturing a semiconductor device, the method comprising chemically and mechanically polishing a substrate (S) used in the semiconductor industry in the presence of a composition as described in any of the foregoing embodiments, wherein the substrate (S) comprises

[0296] (i) Tungsten and / or

[0297] (ii) Tungsten alloys; and

[0298] (iii) At least one dielectric layer selected from silicon, silicon oxide, silicon nitride, or low-k materials.

[0299] 17. The method of claim 16, wherein the ratio of the material removal rate (MRR) of silicon oxide to the material removal rate (MRR) of tungsten is < 15.0.

[0300] 18. The method according to any one of the foregoing embodiments, wherein the static etching rate (SER) of tungsten is < 30 ppb.

[0301] 19. The method according to Example 16 or 17, wherein the material removal rate (MRR) of silicon oxide is > 300 Å / min.

[0302] 20. The method according to Examples 16 to 18, wherein the material removal rate (MRR) of tungsten is < 200 Å / min.

[0303] 21. Use of the composition according to Examples 1 to 15 for polishing a substrate (S), the substrate comprising: (i) tungsten and / or (ii) a tungsten alloy; and (iii) at least one dielectric layer.

[0304] 22. The use according to Example 21, wherein the at least one dielectric is selected from silicon, silicon oxide, silicon nitride, or a low-k material.

[0305] Although the invention claimed herein has been described with respect to specific embodiments thereof, certain modifications and equivalents will be apparent to those skilled in the art and are intended to be included within the scope of the invention claimed herein. Example

[0306] The invention claimed herein is described in detail through the following working examples. More specifically, the testing methods specified below are part of the general disclosure of this application and are not limited to the specific working examples.

[0307] The general procedure for slurry preparation and experimentation is as follows.

[0308] Components:

[0309] • Using the product name Fuso ® PLXC (cationic granules) are commercially available silica granules, and Fuso is available from Fuso Chemical Corporation. ® PL5D (Anion Particles)

[0310] Chlorhexidine and chlorhexidine digluconate are available from Sigma Aldrich.

[0311] • Deionized water available from BASF SE

[0312] • Polyacrylamide (Mn = 10000 g / mol) is available from Sigma-Aldrich.

[0313] • Ethylenediaminetetraacetic acid (EDTA) is available from Sigma-Aldrich.

[0314] • Ferric nitrate nonahydrate is available from Sigma-Aldrich.

[0315] L-Aspartic acid is available from Sigma-Aldrich.

[0316] L-glutamic acid is available from Sigma-Aldrich.

[0317] Slurry composition:

[0318] The slurry composition comprises:

[0319] (A) Silica particles with a particle size of 60 nm to 200 nm and a zeta potential of < -35 mV at a pH of ≥ 2.0 to ≤ 6.0.

[0320] (B) Corrosion inhibitor: Chlorhexidine digluconate

[0321] (C) Oxidizing agent: Ferric nitrate (III)

[0322] (D) Buffer: Aspartic acid or glutamic acid;

[0323] (E) Stabilizer: ethylenediaminetetraacetic acid (EDTA); and

[0324] (F) Deionized water (DIW)

[0325] method

[0326] The inorganic particles (A) used in the example.

[0327] An example according to the invention contains colloidal silica particles (Al) with an average secondary particle size (d2) of 109 nm (as determined by a Malvern Zeta Sizer ZSP instrument using dynamic light scattering (DLS) technology). The silica surface has been partially modified with sulfonic acid.

[0328] Particle shape characterization procedure

[0329] A aqueous cocoon-shaped silica particle dispersion with a solids content of 20 wt.% was dispersed on carbon foil and dried. The dried dispersion was analyzed using energy-filtered transmission electron microscopy (EF-TEM) (120 kV) and scanning electron microscopy secondary electron imaging (SEM-SE) (5 kV). EF-TEM images with a resolution of 2 kJ, 16 bits, and 0.6851 nm / pixel were used for analysis. After noise suppression, the images were binary encoded using a threshold. The particles were then manually separated. Overlying and edge particles were distinguished and not used for analysis. ECD, shape factor, and sphericity were calculated as previously defined, and statistical classification was performed.

[0330] Measurement of zeta potential

[0331] The zeta potential was measured using a Malvern Zetasizer ZSP (software version 7.11) equipped with a DTS1070 disposable folded capillary cell. Measurements were recorded at 25°C and a 0.1% solids concentration. To ensure this, the sample solution (aqueous) was filtered through a Millex SV Low Protein Durapore PVDF membrane (5 µm). The zeta potential was calculated from the measured electromobility and particle size, as obtained by DLS measurements, and fitted to a Smoluchowski model.

[0332] Particle size measurement - Dynamic light scattering (DLS)

[0333] Measurements were performed using a Malvern Zetasizer ZSP equipped with a semi-micro polystyrene cuvette. Measurements were taken by dispersing particles (A) in water (0.1%) at 25°C. Instrument settings: Dispersant: Water (viscosity: 0.8872 mPa) 5 measurements were taken at 60 s each; RI 1.330; automatic attenuator selection was: measurement position fixed at 4.65; analysis model: general. The sample solution (aqueous) was filtered through a Millex SV Low Protein Durapore PVDF membrane (5 µm).

[0334] Figure 3 and Figure 4 The DLS measurements of filtered silica dispersions, measured using Malvern Zetasizer ZSP, are depicted when the zeta potentials of surface-modified colloidal silica particles are > -35 mV and < -35 mV, respectively, in the pH range of ≥ 2.0 to ≤ 6.0. Figure 3This indicates that when the zeta potential of surface-modified colloidal silica particles is > -35 mV (adjusted by KCl) within a pH range of ≥ 2.0 to ≤ 6.0, the DLS method cannot record stable measurements. On the other hand, when the zeta potential of surface-modified colloidal silica particles is < -35 mV within a pH range of ≥ 2.0 to ≤ 6.0, stable signals can be recorded (see reference). Figure 4 ).

[0335] Procedure for preparing slurry compositions

[0336] The components in the slurry composition were thoroughly mixed, and all mixing procedures were carried out under stirring. Aqueous stock solutions of each compound (A), (B), (C), (D), and (E) were prepared by dissolving the required amount of the corresponding compound in ultrapure water (UPW). The pH of the stock solutions was adjusted to the desired value using nitric acid / phosphoric acid. The stock solution for (B) had a concentration of 20 wt.% chlorhexidine digluconate solution, and for (C) it was 0.08 wt.%. For (A), a dispersion, as supplied by the supplier, was typically used, with an abrasive concentration of approximately 20%–30% by weight.

[0337] Alternatively, the oxidant (C) can be used in the form of a Fe(III)EDTA solution, which can be obtained by commonly known methods. For example, as reported by Lind et al., Stereochemistry of Ethylenediamintetraacetato Complexes, Inorganic Chemistry, Vol. 3, No. 1, 1964 (pp. 34 and thereafter).

[0338] Prior to CMP, the final composition is passed through a 0.1 μm syringe filter. Filtration is an important industrial process, and the colloidal stability of this composition is further enhanced by its ability to remain colloidal after microfiltration.

[0339] pH measurement

[0340] pH values ​​were measured using a pH combination electrode (Schott, blue line 22 pH electrode).

[0341] Static Etching Rate (SER) Experiment of W

[0342] The SER experiment is conducted as follows:

[0343] • Cut the tungsten (W) coated wafer into several 2.5 × 2.5 cm test pieces and wash them with deionized water (DIW).

[0344] • Treat each sample with 0.1% citric acid solution for 4 min, and then wash with DIW.

[0345] • Place 300 ml of freshly prepared slurry in a beaker and heat it to 60°C.

[0346] • Place the tungsten (W) sample in the slurry and keep it in the slurry for 10 min in the SER device.

[0347] • Remove the tungsten (W) sample and rinse it with DIW for 1 min and dry it with nitrogen.

[0348] • The concentration of tungsten ions in the etched slurry was measured by ICP-MS.

[0349] Standard CMP process for polishing wafers with a 300 mm barrier layer:

[0350] The GnP POLI-500 polishing tool is used to planarize semiconductor thin films on silicon wafers with sample dimensions. Several different configurations are available depending on the user's requirements for carrier type, pads, and trimming. CMP parameter settings on the GnP tool (such as polishing pressure, pad trimming pressure, slurry flow rate, and carrier / platform rotation speed) are configured before polishing to achieve the desired flatness and material removal rate.

[0351] Before the polishing process begins, the pads on the platform are conditioned. Conditioning involves using a diamond disc to remove any debris or hardened material from the pad surface and restore its optimal texture. The sample wafer is placed face down on a carrier with a specific film support, the film having a square groove in the center, and its dimensions matching the sample wafer.

[0352] The CMP process begins by bringing a rotating polishing pad into contact with the wafer. A slurry flows onto the pad, and a carrier contacts the rotating pad downwards. During rotation, the slurry is evenly distributed across the pad. The rotation of the stage creates relative motion between the wafer and the pad, generating shear forces that remove excess material from the wafer surface. Abrasive particles in the slurry remove material from the wafer, while chemicals provide selectivity and optimize the polishing rate.

[0353] After the CMP process, the wafer surface is thoroughly cleaned to remove any residual paste, particles, or contaminants for post-process measurements.

[0354] Material removal rate

[0355] Polishing experiments used to determine the material removal rate were performed on a 300 mm whole wafer mounted on an Applied Materials 300 mm Reflexion polisher.

[0356] Polishing removal rate experiments were conducted on the following materials: 300 mm monolithic 15 kA thick TEOS wafers from Ramco, W monolithic wafers also from Ramco, and Ti and TiN monolithic wafers available from AMT. Unless otherwise specified, all polishing experiments were conducted using H600 polyurethane polishing pads (commercially available from Fujibo Inc.) with a typical downforce of 13.8 kPa (2.0 psi), a chemical mechanical polishing composition flow rate of 300 mL / min, a stage rotation speed of 123 rpm, and a carrier rotation speed of 117 rpm. The polishing pads were dressed using an A189L diamond pad dresser (commercially available from 3M). The polishing pads were pre-dressed with the dresser for 30 minutes at a downforce of 5.0 psi (2.3 kg) and a speed of 101 rpm (stage) / 108 rpm (dresser). The material removal rate of W was determined using a KLA-Tencor RS-100C metering instrument. The material removal rate of TEOS was determined using a KLA-Tencor OP-5300 metering instrument.

[0357] Using AFM to measure surface defects:

[0358] The Parksystem NX10 - Atomic Force Microscopy (AFM) is a technique for imaging the surface of a sample at atomic resolution. It produces images by scanning the sample surface in a non-contact mode using a sharp tip. The AFM probe is mounted on a cantilever, which acts as a tiny spring detecting the forces between the tip and the sample surface. These forces can include van der Waals forces, electrostatic forces, magnetic forces, and more. The interaction between the tip and the sample causes a tiny deflection of the cantilever.

[0359] The sample is placed on a stable stage below the AFM instrument, and the sample surface is clean and optimized for analysis. The AFM probe is brought close to the sample surface using a piezoelectric scanner. As the tip approaches the surface, the atomic forces between the tip and the sample become significant. The piezoelectric scanner moves the sample stage to achieve the desired scan. The scanner records the height / position of the probe during movement, and the deflection of the cantilever is detected using a laser beam deflection method. A position-sensitive photodetector continuously monitors the cantilever deflection caused by atomic forces. The laser beam is directed onto the back of the cantilever, and the deflection is detected. This information is used in the feedback loop to adjust the vertical position of the probe, thus keeping the deflection within the desired range. This maintains a constant force between the tip and the sample.

[0360] At each location, data on the height or displacement of the cantilever are collected. This data is used to construct a topographic image of the sample surface. The raw data is processed and analyzed to create the final image. An algorithm is used to convert the height data into a visual representation.

[0361] Disc-shaped indentation measurement

[0362] The Parksystem NX10 - Atomic Force Microscopy (AFM) is a technique for imaging the surface of a sample at atomic resolution. It produces images by scanning the sample surface in a non-contact mode using a sharp tip. The AFM probe is mounted on a cantilever, which acts as a tiny spring detecting the forces between the tip and the sample surface. These forces can include van der Waals forces, electrostatic forces, magnetic forces, and more. The interaction between the tip and the sample causes a tiny deflection of the cantilever.

[0363] The sample is placed on a stable stage below the AFM instrument, and the sample surface is clean and optimized for analysis. An AFM probe is brought close to the sample surface using a piezoelectric scanner. As the tip approaches the surface, the atomic forces between the tip and the sample become significant. The piezoelectric scanner moves the sample stage to achieve the desired scan. The scanner records the height / position of the probe as it moves, detecting the cantilever deflection using a laser beam deflection method. A position-sensitive photodetector continuously monitors the cantilever deflection caused by atomic forces. The laser beam is directed to the back of the cantilever and detects the cantilever deflection. This information is used in the feedback loop to adjust the vertical position of the probe, thus keeping the deflection within the desired range. This maintains a constant force between the tip and the sample. At each location, data on the height or displacement of the cantilever is collected. This data is used to construct a topographic image of the sample surface. The raw data is processed and analyzed to create the final image. Algorithms are used to convert the height data into a visual representation.

[0364] Measurements are scanned from a point on boundary A to location B. For example, B is identified as the center point in a silicon oxide / dielectric plug / wire, flanked by metals such as tungsten (location A is located on tungsten). For both the pre-CMP and post-CMP samples, the step height is recorded as BA. The post-CMP height value is subtracted from the pre-CMP height value, resulting in a negative value in the case of a dish-shaped depression.

[0365] Table 1: Examples of the present invention - All concentrations are expressed in wt.% relative to the total composition.

[0366]

[0367] Unless otherwise specified, the concentration of the buffer is 0.3 wt.%.

[0368] Table 1 continues.

[0369]

[0370] Unless otherwise specified, the concentration of the buffer is 0.3 wt.%.

[0371] Table 2: Comparative Examples - All concentrations are expressed as wt.% relative to the total composition.

[0372]

[0373] Unless otherwise specified, the concentration of the buffer is 0.5 wt.%.

[0374] Experimental results

[0375] Table 3

[0376]

[0377] Results Discussion

[0378] Table 3 shows the Static Etching Rate (SER), Material Removal Rate (MRR), and Dielectric (TEOS) dish depression values ​​for different compositions. It is noted that the combinations of various components (A) through (F) are crucial for providing acceptable polishing efficiency and solution stability for Examples 1-8 of the present invention. The zeta potential of unmodified silica particles was found to increase under acidic conditions (pH < 7) (see reference). Figure 1 However, surprisingly, it was found that the surface-modified colloidal silica particles maintained a consistently low zeta potential (in the range of -35 to -60 mV), thus providing colloidal stability even under acidic conditions. It was found that using anionic colloidal silica particles according to the present invention (…) Figure 2 The composition of a) polished substrate showed a smooth surface, while cationic colloidal silica particles ( Figure 2 b) This results in agglomerates that are clearly visible on the substrate surface (corresponding to Comparative Example C6). The combination of chlorhexidine or chlorhexidine digluconate as a corrosion inhibitor (B) with an acidic amino acid (D) having an isoelectric point (pI) of ≤ 5.0 not only provides a SER of less than 30 ppb for tungsten within the provided pH range, but also provides a suitably low dishing depression for the dielectric (TEOS). It is further noted that the addition of chlorhexidine to the composition in the absence of component (D) (Comparative Example C1) or component (B) (Comparative Example C4) results in undesirable effects, such as high TEOS dishing depression and high tungsten (W) SER, respectively.

[0379] Furthermore, various acidic amino acids with isoelectric points (pI) ≤ 5.0 were tested, and as can be seen from the results summarized in Table 3, compositions containing these buffers showed suitable results. On the other hand, it was noted that the presence of neutral amino acids such as glycine (Comparative Example C2) or basic amino acids such as arginine (Comparative Example C3) resulted in undesirable high TEOS disc-shaped depressions.

[0380] Compositions according to examples of the invention claimed herein exhibit improved performance with high SiO2 (TEOS) MRR, low tungsten MRR, low tungsten SER, low tungsten and TEOS disc depression, while having colloidal or high dispersion stability and low alkali content.

Claims

1. A dielectric polishing composition comprising (A) Surface-modified colloidal silica particles, wherein the surface of these particles contains negatively charged groups, wherein these surface-modified colloidal silica particles... The particles have a negative charge. Particle sizes ranging from 60 nm to 200 nm, and ζ potential ≤ -35 ​​mV at pH range ≥ 2.0 to ≤ 6.0; (B) At least one corrosion inhibitor selected from at least one guanidine derivative; (C) At least one iron (III) oxidant, wherein the concentration of the iron (III) oxidant (C) is in the range of ≥ 0.003 wt.% to ≤ 0.1 wt.%; (D) At least one buffer selected from at least one acidic amino acid having an isoelectric point (pI) of ≤ 5.0; (E) At least one stabilizer selected from acetic acid, acetylacetone, oxalic acid, alendronate, acetic acid, phthalic acid, citric acid, adipic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, oxalic acid, maleic acid, gluconic acid, mucoconic acid, ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, N,N-bis(carboxymethyl)alanine, hypozoxytriacetic acid, diethylenetriaminepentaacetic acid, bis(salicylene)ethylenediamine, aminotris(methylenephosphonic acid), diethylenetriaminepenta(methylphosphonic acid), ethylenediaminetetra(methylenephosphonic acid), or mixtures thereof; and (F) Aqueous medium, The pH of the composition is in the range of ≥ 2.0 to ≤ 4.3, and The composition contains ≤ 1 ppm of polyacrylamide.

2. The composition according to any one of claims 1, wherein, Based on the total weight of the composition, the concentration of these surface-modified colloidal silica particles (A) is in the range of ≥ 3.2 wt.% to ≤ 13.0 wt.%.

3. The composition according to any one of claims 1 to 2, wherein, The guanidine derivative is selected from butylguanidine, phenformin, guanine, chloroguanidine hydrochloride, 2-guanidinylbenzimidazole, polyhexamethylene biguanide hydrochloride, polyaminopropyl biguanide, aracetin, chlorhexidine or chlorhexidine salt, preferably chlorhexidine or chlorhexidine salt.

4. The composition according to any one of claims 1 to 3, wherein, The iron(III) oxidant (C) is selected from ferric(III) nitrate or its hydrate.

5. The composition according to any one of claims 1 to 4, wherein, The buffer (D) is an acidic amino acid selected from aspartic acid or glutamic acid.

6. The composition according to any one of claims 1 to 5, wherein, The composition has a potassium content of ≤10 ppm.

7. The composition according to any one of claims 1 to 6, wherein, The composition is used for polishing a substrate (S), wherein the substrate (S) comprises: (i) tungsten and / or (ii) a tungsten alloy; and (iii) at least one dielectric layer selected from silicon, silicon oxide, silicon nitride, or a low-k material.

8. A method for manufacturing a semiconductor device, the method comprising chemically and mechanically polishing a substrate (S) used in the semiconductor industry in the presence of the composition as described in any one of claims 1 to 7, wherein the substrate (S) comprises (i) Tungsten and / or (ii) Tungsten alloys; and (iii) At least one dielectric layer selected from silicon, silicon oxide, silicon nitride, or low-k materials.

9. The method according to claim 8, wherein, The ratio of the material removal rate (MRR) of silica to that of tungsten is < 15.

0.

10. The method according to any one of claims 8 to 9, wherein, The static etching rate (SER) of tungsten is < 30 ppb.

11. The method according to any one of claims 8 to 10, wherein, The material removal rate (MRR) of silicon oxide is >300 Å / min.

12. The method according to any one of claims 8 to 11, wherein, The material removal rate (MRR) of tungsten is < 200 Å / min.

13. Use of the composition according to any one of claims 1 to 7 for polishing a substrate (S), the substrate comprising: (i) tungsten and / or (ii) tungsten alloys; (iii) at least one dielectric layer.

14. The use according to claim 13, wherein, The at least one dielectric is selected from silicon, silicon oxide, silicon nitride, or low-k materials.

Images