Polishing compound, polishing process, method for producing a semiconductor component, polishing additive solution and method for producing a polishing additive solution

Abstract

A polishing compound with excellent pH stability, an additive solution for the polishing compound for its preparation, a method for its preparation, a polishing method capable of high-speed polishing, and a method for manufacturing a semiconductor component using the polishing method are provided. The polishing compound contains (bi)carbonate of a primary amine, a secondary amine, a tertiary amine, or a quaternary ammonium compound and water, wherein an organic group comprising the amine or ammonium is selected from a linear alkyl group, a branched alkyl group, and an alkanol group, the (bi)carbonate content is 5 mmol / L to 130 mmol / L based on the total polishing compound, the boiling point of the amine or ammonium is 0 °C to 500 °C, and the pH is 7 to 11.

Description

Technical field

[0001] The present invention relates to a polishing agent, a polishing method, a method for producing a semiconductor component, an additive solution for a polishing agent and a method for producing an additive solution for a polishing agent. State of the art

[0002] As the packing densities of integrated semiconductor circuits increase and their functions become more complex, the development of microfabrication technologies is progressing, enabling the design of finer and denser semiconductor device structures. In the fabrication of integrated semiconductor circuit devices (hereinafter referred to as semiconductor devices), interlayer insulating films, buried wiring traces, and the like are conventionally smoothed by chemical-mechanical polishing (hereinafter referred to as CMP) to prevent surface irregularities (height differences) on a layer from exceeding the depth of focus of lithography and thus failing to achieve sufficient resolution. As the demand for the fabrication of more precise and finer devices grows, the importance of the high flatness achieved through CMP is becoming increasingly significant.

[0003] Furthermore, shallow trench isolation (STI) was introduced in the manufacture of semiconductor devices, where the isolation width of the elements is small in order to make semiconductor devices even finer.

[0004] STI is a method for forming an electrically insulated element region by creating a trench (a groove) in a silicon substrate and embedding an insulating film in the trench. An example of STI is given with reference to Fig. 1A and Fig. 1B described. In this example, it is first explained as in Fig.Figure 1A shows an elemental region on a silicon substrate 1 masked with a stopper film 2. A trench 3 is then formed in the silicon substrate 1, and an insulating film, such as a silicon oxide film 4, is applied to fill the trench 3. Next, CMP is used to leave the portion of the silicon oxide layer 4 located within the trench 3 (the recessed part) intact, while the remaining portion of the silicon oxide layer 4, located above the stopper film 2 (the raised part), is polished and thus removed. This results in an elemental isolation structure where the silicon oxide layer 4 is embedded in the trench 3, as shown in Figure 1A. Fig. 1B shown.

[0005] As an example of a polishing agent used for CMP, patent literature 1 discloses a polishing agent containing cerium oxide particles, water-soluble polyamine, potassium hydroxide and an organic acid, and having a pH of 10 or more. Citation list for patent literature

[0006] Patent literature 1: Japanese unpublished patent application no. 2016-154208 Summary of the invention: Technical problem

[0007] It is known that the polishing performance of a polishing compound varies depending on pH changes. To stabilize the polishing compound's performance, a compound with excellent pH stability was required. Alkaline polishing compounds, in particular, tend to become acidic when they absorb carbon dioxide gas from the air, leading to the problem that their polishing performance is likely to be unstable.

[0008] In view of the problem described above, the objective of the present disclosure is to provide a polishing agent with excellent pH stability, an additive solution for a polishing agent for preparing the polishing agent and a method for its preparation, a polishing method with which high-speed polishing can be carried out, and a method for producing a semiconductor component using the polishing method. Solution to the problem

[0009] The present disclosure provides a polishing agent, a polishing process, a process for manufacturing a semiconductor component, an additive solution for a polishing agent and a process for manufacturing an additive solution for a polishing agent. [1] A polishing agent contains: Abrasive grains; and (Bi)carbonate of a primary amine, a secondary amine, a tertiary amine or a quaternary ammonium, and water, wherein an organic group that contains the amine or the ammonium, a group that is selected from a linear alkyl group, a branched alkyl group and an alkanol group, a (bi)carbonate content of 5 mmol / L to 130 mmol / L, based on the total polishing agent, is, a (bi)carbonate content of 5 mmol / L to 130 mmol / L, based on the total polishing agent, is, a boiling point of the amine or ammonium is 0 °C to 500 °C, and the pH value is between 7 and 11. [2] The polishing agent according to point [1], wherein the molecular weight of the (bi)carbonate is 500 or less. [3] The polishing agent according to point [1] or [2], wherein the melting point of the amine or the ammonium is -180 °C to 0 °C. [4] The polishing agent according to one of points [1] to [3], wherein an absolute value of a difference between the pKa value of ammonium ions in the (bi)carbonate and the pH value of the polishing agent is 3 or less. [5] The polishing agent according to one of points [1] to [4], wherein the organic group includes an alkanol group. [6] The polishing agent according to one of points [1] to [5], wherein the (bi)carbonate comprises (bi)carbonate of a tertiary amine. [7] The polishing agent according to any of points [1] to [5], wherein the abrasive grains include at least one type selected from the group consisting of silica particles, aluminium oxide particles, zirconium oxide particles, cerium compound particles, titanium oxide particles, germanium oxide particles, composite particles thereof and core-shell particles. [8] The polishing agent according to one of points [1] to [7], wherein the abrasive grains contain cerium compound particles. [9] The polishing agent according to one of points [1] to [8], wherein the abrasive grains contain cerium oxide particles.

[10] The polishing compound according to any of points [1] to [9], wherein the abrasive grain content is 0.01 wt.% to 10.0 wt.%, based on the total weight of the polishing compound.

[11] A polishing process in which a polishing pad is brought into contact with a surface of a semiconductor substrate to be polished, while a polishing agent is supplied between them, and the surface to be polished is polished by a relative movement of the surface to be polished and the polishing pad, where the polishing agent is the polishing agent according to one of points [1] to

[10] .

[12] The method for producing a semiconductor component, wherein the semiconductor component is obtained by dividing a semiconductor substrate having a surface to be polished, which has been polished by the polishing method according to point

[11] .

[13] An additive solution for a polishing agent containing (bi)carbonate of a primary amine, a secondary amine, a tertiary amine or a quaternary ammonium, and water, wherein an organic group having the amine or the ammonium is a group selected from a linear alkyl group, a branched alkyl group, an alkanol group ...

[14] A method for producing the additive solution for the polishing agent described in point

[13] , comprising: Dissolving a primary amine, a secondary amine, a tertiary amine, or a quaternary ammonium salt in water; and Adding carbon dioxide gas to the water to produce (bi)carbonate. Advantageous effects of the invention

[0010] According to the present disclosure, it is possible to provide a polishing agent with excellent pH stability, an additive solution for a polishing agent for preparing the polishing agent and a method for its preparation, a polishing method that enables high-speed polishing, and a method for producing a semiconductor component using the polishing method. Brief description of the drawings Fig. Figure 1A shows an example of a polishing process and is a cross-sectional diagram showing the condition of an object to be polished before polishing; Fig. Figure 1B shows an example of the polishing process and is a cross-sectional diagram showing the condition of the object to be polished after polishing; and Fig. Figure 2 is a schematic diagram showing an example of a polishing device. Description of the embodiments

[0011] The following describes embodiments of the present invention. The present invention is not limited to the embodiments shown below, and other embodiments may also fall within the scope of the present invention, provided they are consistent with the purpose of the present invention. To clarify the explanation, the following descriptions and drawings have been simplified accordingly. Furthermore, the scales of the elements in the drawings may differ significantly for illustrative purposes.

[0012] It should be noted that in the present invention, the term "surface to be polished" refers to a surface of an object to be polished, for example, its front face. The description of the present application also includes surfaces in intermediate stages, i.e., surfaces that occur during a process for manufacturing a semiconductor device in semiconductor substrates, as part of the "surface to be polished".

[0013] The term "silicon oxide" mainly refers to silicon dioxide, but is not limited to silicon dioxide and can also include silicon oxides other than silicon dioxide.

[0014] The term "selectivity ratio" refers to a ratio (R A / R B ) between the rate of erosion (R A ) of an object A to be polished (e.g. a silicon oxide layer) and the removal rate (R B ) a stop layer B (e.g. a silicon nitride layer).

[0015] The term “(Bi)carbonate” is a generic term for carbonates and bicarbonates.

[0016] The term "amine" is a general term for primary amines, secondary amines, and tertiary amines. Furthermore, amine and ammonium can be collectively referred to as "amine or the like".

[0017] Unless otherwise specified, the use of a symbol “-” (or “to”) indicating a range of numbers means that the numerical value preceding the symbol and the numerical value following the symbol are included as the lower and upper limits of the range, respectively. [Polishing compound]

[0018] The polishing agent according to the present invention (hereinafter also referred to as the polishing agent disclosed herein) is a polishing agent comprising (bi)carbonate of a primary amine, a secondary amine, a tertiary amine or a quaternary ammonium, and water, wherein an organic group comprising the amine or the ammonium is a group selected from a linear alkyl group, a branched alkyl group and an alkanol group, the (bi)carbonate content is 5 mmol / L to 130 mmol / L, based on the total polishing agent, the boiling point of the amine or the ammonium is 0 °C to 500 °C and the pH is 7 to 11.

[0019] Since the polishing agent disclosed herein contains (bi)carbonate of amine or the like, the absorption of carbon dioxide from the atmosphere can be suppressed, and pH changes can be suppressed even at a pH of 7 or higher. This stabilizes the polishing performance of the polishing agent.

[0020] The polishing agent disclosed herein contains at least abrasive grains, (bi)carbonate of amine or the like, and water, and may further contain other components, as long as the effect of the present invention is achieved. The individual components that may be contained in the polishing agent disclosed herein are described below. <(Bi)carbonate of amine or ammonium>

[0021] The polishing agent described herein contains (bi)carbonate of the specific amine described above or the like. Since the aforementioned (bi)carbonate is unlikely to absorb carbon dioxide, it exhibits excellent pH stability. Furthermore, amines and ammonium exhibit higher pH stability than ammonia due to their lower volatility.

[0022] (Bi)Carbonate can either be a salt of carbonate ions (CO3) 2- ) or a salt of bicarbonate ions (HCO3) - The ratio of carbonate ions to bicarbonate ions depends on the pH value or similar parameters of the polishing agent. Regardless of the ratio, (bi)carbonate affects pH stability.

[0023] Furthermore, the amine or ammonium used in the polishing agent disclosed herein has a group selected from a linear alkyl group, a branched alkyl group and an alkanol group.

[0024] The linear alkyl group is preferably an alkyl group with a carbon number of 1 to 24 and preferably an alkyl group with a carbon number of 1 to 12. Specific examples of the linear alkyl group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-hexyl group and an n-octyl group.

[0025] The branched alkyl group is preferably an alkyl group with a carbon number of 3 to 24 and more preferably an alkyl group with a carbon number of 3 to 12. Specific examples of the branched alkyl group include an isopropyl group, a sec-butyl group, an isobutyl group, a tert-butyl group and a tert-butyl group.

[0026] Furthermore, examples of the alkanol group include a structure in which one or more hydrogen atoms of the aforementioned linear or branched alkyl group are substituted by a hydroxyl group. Specific examples of the alkanol group include a hydroxyethyl group and a hydroxypropyl group.

[0027] Two or more organic groups in the secondary amine, the tertiary amine, and the quaternary ammonium compound can be the same group or different groups. In the polishing agent disclosed herein, the amine or the like preferably has an alkanol group, since this results in a high boiling point (low volatility), increased solubility, and a more stable pH.

[0028] The boiling point of the amine or similar compound ranges from 0 °C to 500 °C. Using an amine or similar compound with a boiling point of 0 °C or higher improves pH stability. Furthermore, using an amine or similar compound with a boiling point of 500 °C or less simplifies the distillation and purification of the amine when synthesizing (bi)carbonates of amine or similar compounds.

[0029] The lower limit of the boiling point of the amine or the like is preferably 30 °C, more preferably 50 °C, and further preferably 70 °C to further improve pH stability. The higher the boiling point of the amine or the like, the more the pH changes associated with evaporation are suppressed, leading to a further improvement in pH stability. On the other hand, the upper limit of the boiling point of the amine or the like is preferably 400 °C and more preferably 300 °C, taking into account the availability of (bi)carbonate.

[0030] The upper limit of the melting point of the amine or the like is determined taking into account the preparation of the polishing compound. The melting point is preferably low because, during the thermal melting of the amine or the like at the time of preparation of the polishing compound, there is a possibility that the amine or the like will be oxidized due to the presence of oxygen in the atmosphere, and if the amine or the like is a (bi)carbonate, it may decompose due to the formation of carbamic acid or urea derivatives. Considering the above points, the upper limit of the melting point of the amine or the like is preferably 0 °C, more preferably -30 °C, further preferably -50 °C, and particularly preferably -80 °C. On the other hand, the lower limit of the melting point of the amine or the like is preferably -180 °C and more preferably -140 °C with regard to handling by solidification.

[0031] Specific examples of amines and ammonium include primary amines such as methylamine, ethylamine, propylamine, isopropylamine, butylamine, hexylamine, heptylamine, octylamine, monoethanolamine, isopropanolamine, 2-amino-1-propanol, 3-amino-1-propanol; secondary amines such as dimethylamine, diethylamine, methylethylamine, dibutylamine, diethanolamine and diisopropanolamine; Tertiary amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, triethanolamine, triisopropanolamine, ethyldiethanolamine, butyldiethanolamine and dimethylpropan-1-amine; Quaternary ammonium compounds such as tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, ethyltrimethylammonium, diethyldimethylammonium and methyltriethylammonium. To further improve pH stability, a tertiary amine or a quaternary ammonium compound is preferred among these, with a tertiary amine being more preferred and a tertiary amine with an alkanol group being even more preferred.

[0032] The molecular weight of the (bi)carbonate of the amine or the like is preferably as low as possible, preferably 50 to 500 and further preferably 50 to 300, so that it is possible to reduce the amount to be added and thus reduce the environmental impact.

[0033] Furthermore, the pKa value of ammonium ions in (bi)carbonate of amine or the like is preferably 7 to 12, more preferably 7.5 to 11 and further preferably 8 to 11 with regard to pH stability.

[0034] Likewise, taking into account the pH stability, the absolute value |pKa-pH| of a difference between the pKa value of ammonium ions in (bi)carbonate of amine or the like and the pH value of the polishing agent disclosed herein is preferably 3 or less, more preferably 2 or less, further preferably 1.5 or less and particularly preferably 1.0 or less.

[0035] The ammonium ions described above represent conjugate acids of amine or the like, and if the pKa value of the ammonium ions is equal to or higher than the pH of the polishing agent, most of the amine or the like is converted to ammonium ions. In particular, if, for example, the pKa value is 1 or more greater than the pH of the polishing agent, approximately 90% or more of the amine or the like is converted to ammonium ions. The amine or the like, in the form of ammonium ions, evaporates less readily, and even if, for example, the boiling point of the amine or the like is low, it exhibits excellent pH stability and low volatility, thus preventing adverse effects on other adjacent plates in the CMP apparatus.

[0036] The content of (bi)carbonate of amine or the like is preferably 5 mmol / L to 130 mmol / L and more preferably 10 mmol / L to 80 mmol / L, based on the total polishing agent, to further improve pH stability. (Process for the production of (bi)carbonate of amine or the like)

[0037] (Bi)carbonate of amine or the like can be a commercially available product. Furthermore, (bi)carbonate of amine or the like can be produced by adding carbon dioxide gas to a desired amine or the like to be used.

[0038] Specific examples of a process for the production of (bi)carbonate of amine or the like include (I) a process for preparing an aqueous solution of amine or the like and for absorbing carbon dioxide gas through this aqueous solution; (II) a process for mixing dry ice and amine or the like; and (III) a process for mixing ammonium (bi)carbonate and amine or the like, dissociating ammonia by weak base dissociation, and removing the dissociated ammonia.

[0039] In the above-mentioned process (I), the carbon dioxide gas can be either highly purified gas or CO2 in the atmosphere. Alternatively, (bi)carbonate of amine or the like, produced by an amine absorption process or the like, also known as direct air capture (DAC) of CO2, can be used. <Schleifkörner>

[0040] In the polishing compound disclosed herein, the abrasive grains can be suitably selected from those used as abrasive grains for CMP. Examples of abrasive grains include at least one type selected from the group consisting of silica particles, aluminum oxide particles, zirconium oxide particles, cerium compound particles (e.g., cerium oxide particles, cerium hydroxide particles), titanium oxide particles, germanium oxide particles, and core-shell particles that utilize these particles as core particles. Examples of silica particles include colloidal silica and pyrogenic silica. Colloidal aluminum oxide can also be used as the aluminum oxide particle.

[0041] The core-shell particles consist of core particles (e.g. silica particles, aluminum oxide particles, zirconium oxide particles, cerium compound particles, titanium oxide particles or germanium oxide particles) and thin films that cover the surfaces of the core particles.

[0042] Examples of thin-film materials include at least one type selected from oxides such as silicon dioxide, aluminum oxide, zirconium oxide, cerium oxide, titanium oxide, germanium oxide, iron oxide, manganese oxide, zinc oxide, yttrium oxide, calcium oxide, magnesium oxide, lanthanum oxide, and strontium oxide. Furthermore, the thin film can be composed of a variety of nanoparticles made from these oxides.

[0043] The particle size of the above-mentioned nuclear particles is preferably 0.01 µm to 0.5 µm and more preferably 0.03 µm to 0.3 µm.

[0044] It is sufficient if the particle size of the above-mentioned nanoparticles is smaller than the particle size of the above-mentioned nuclear particles, with the particle size of the nanoparticles preferably being 1 nm to 100 nm and more preferably 5 nm to 80 nm.

[0045] Among the abrasive grains mentioned above, silica particles, aluminum oxide particles, or cerium compound particles are preferred due to their excellent removal rate from the insulating film. Furthermore, cerium compound particles are more preferred, and cerium oxide particles are even more preferred, as a high removal rate can be achieved when the surface to be polished includes an insulating film (especially a silicon oxide film). In the case of core-shell particles, the thin film preferably contains silicon dioxide, aluminum oxide, or a cerium compound. More preferably, the thin film contains cerium oxide. Only one type of abrasive grain can be used, or two or more types of abrasive grains can be used in combination.

[0046] The cerium oxide content, based on the total weight of the abrasive grains, is preferably 70 wt.% or more, more preferably 80 wt.% or more, even more preferably 90 wt.% or more, particularly preferably 95 wt.% or more, and most preferably 100 wt.%. In particular, if the cerium oxide content, based on the total weight of the abrasive grains, is 70 wt.% or more, the removal rate of the insulating film can be easily improved.

[0047] Cerium oxide particles can be suitably selected and used from known particles. Examples of known cerium oxide particles include cerium oxide particles produced by processes disclosed in Japanese unexamined patent application Publication No. H11-12561, Japanese unexamined patent application Publication No. 2001-35818, and the published Japanese translation of the international PCT publication for patent application No. 2010-505735.Specifically, examples include cerium oxide particles obtained by producing cerium hydroxide gel by adding an alkali to an aqueous solution of cerium(IV) ammonium nitrate and subsequently filtering, washing, and calcining the resulting gel; cerium oxide particles obtained by pulverizing and subsequently calcining high-purity cerium carbonate and further pulverizing and classifying the pulverized and calcined cerium carbonate; and cerium oxide particles obtained by chemical oxidation of a cerium(III) salt in a liquid.

[0048] The cerium oxide particles may contain impurities that differ from pure cerium oxide. However, the cerium oxide content in a cerium oxide particle is preferably 80 wt.% or more, more preferably 90 wt.% or more, further preferably 95 wt.% or more, and most preferably 100 wt.% (without impurities). If the cerium oxide content in the cerium oxide particles is 80 wt.% or more, the removal rate of the insulating film can be easily improved.

[0049] The average particle size of the abrasive grains is preferably 0.01 µm to 0.5 µm and more preferably 0.03 µm to 0.3 µm. If the average particle size is 0.5 µm or less, the mechanical effect on the surface to be polished is reduced, thus suppressing the occurrence of polishing defects such as scratches. If the average particle size is 0.01 µm or more, aggregation of the abrasive grains is also suppressed, resulting in excellent storage stability of the polishing compound and an excellent material removal rate.

[0050] It should be noted that if the abrasive grains are dispersed in the liquid and not aggregated, the particle size described above is the particle size of the primary particles. If the abrasive grains are aggregated in the liquid, the particle size mentioned above is the particle size of the aggregated particles (secondary particles). In both cases, the average particle size is measured using a dispersion liquid in which abrasive grains are dispersed in a dispersion medium such as pure water, and using a particle size distribution meter such as a laser diffraction / scattering meter.

[0051] The lower limit for the abrasive grain content is preferably 0.01 wt.%, more preferably 0.05 wt.%, even more preferably 0.1 wt.%, and most preferably 0.15 wt.%, based on the weight of the polishing compound. If the abrasive grain content is equal to or higher than the aforementioned lower limit, an excellent material removal rate can be achieved for the surface to be polished. Conversely, the upper limit for the abrasive grain content is preferably 10.0 wt.%, more preferably 8.0 wt.%, even more preferably 5.0 wt.%, most preferably 2.0 wt.%, even more preferably 1.0 wt.%, most preferably 0.8 wt.%, and most preferably 0.5 wt.%, based on the weight of the polishing compound.If the abrasive grain content is equal to or lower than the upper limit, the agglomeration of the abrasive grains can be suppressed; the increase in the viscosity of the polishing agent disclosed herein can be suppressed; and the handling properties are excellent.

[0052] The zeta potential (surface potential) of the abrasive grains in the polishing compound is preferably negative (lower than 0 mV), more preferably -200 mV to -10 mV, more preferably -150 mV to -20 mV, and most preferably -100 mV to -30 mV. If the zeta potential of the abrasive grains lies within the range described above, the dispersion stability of the abrasive grains and the flatness of the silicon oxide film after polishing can be improved.

[0053] The zeta potential of the abrasive grains can be measured using a dynamic light scattering zeta potential meter (example: product name: DelsaNano C, manufactured by Beckman Coulter Co., Ltd.). The zeta potential of the abrasive grains can be adjusted using a water-soluble polymer, an acidic compound, an additive, or the like (described later). <wasser>

[0054] The polishing compound described herein contains water as a medium in which abrasive grains are dispersed. The type of water is not restricted to any particular type. However, considering the effects on other components, the avoidance of contamination by impurities, and the effects on pH, etc., it is preferable to use pure water, ultrapure water, ion-exchange water, or the like. <additiv>

[0055] The polishing compound disclosed herein may also contain various additives. Examples of additives include a pH adjuster, a dispersant, an agglomeration inhibitor, a lubricant, a viscosity improver, and a preservative. Furthermore, the polishing compound may contain two or more types of additives. While the (bi)carbonate of amine or the like described above may also be contained in the pH adjuster, in the polishing compound disclosed herein, the (bi)carbonate of amine or the like is treated separately from the pH adjuster. (pH adjusting agent)

[0056] A pH adjuster may be included to adjust the pH to a specific value. The pH adjuster can be appropriately selected from acidic compounds, basic compounds, or amphoteric compounds such as amino acids and their salts.

[0057] Examples of acidic compounds include inorganic acids, organic acids, or their salts. Examples of inorganic acids include nitric acid, sulfuric acid, hydrochloric acid, and phosphoric acid. Furthermore, their ammonium salts, sodium salts, potassium salts, or the like can be used.

[0058] Examples of organic acids include compounds with a carboxyl group, a sulfo group or a phospho group as an anionic group and their ammonium salts, sodium salts, potassium salts or the like.

[0059] Examples of organic acids with a carboxyl group include alkyl monocarboxylic acids such as formic acid, acetic acid, and propionic acid;

[0060] Carboxylic acids with a heterocycle such as 2-pyridinecarboxylic acid, 3-pyridinecarboxylic acid, 4-pyridinecarboxylic acid, 2,3-pyridindicarboxylic acid, 2,4-pyridindicarboxylic acid, 2,5-pyridindicarboxylic acid, 2,6-pyridindicarboxylic acid, 3,4-pyridindicarboxylic acid, 3,5-pyridindicarboxylic acid, pyrazinecarboxylic acid, 2,3-pyrazindicarboxylic acid, 2-quinolinecarboxylic acid, pyroglutamic acid, picolinic acid, DL-pipecolic acid, 2-furancarboxylic acid, 3-furancarboxylic acid, tetrahydrofuran-2-carboxylic acid and tetrahydrofuran-2,3,4,5-tetracarboxylic acid; alicyclic carboxylic acids such as cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cycloheptanecarboxylic acid and cyclohexylcarboxylic acid; Carboxylic acids containing an amino group, such as alanine, glycine, glycylglycine, aminobutyric acid, N-acetylglycine, N,N-di(2-hydroxyethyl)glycine, N-(tert-butoxycarbonyl)glycine, proline, trans-4-hydroxy-L-proline, phenylalanine, sarcosine, hydantoic acid, creatine, N-[tris(hydroxymethyl)methyl]glycine, glutamic acid and aspartic acid; Carboxylic acids containing a hydroxyl group, such as lactic acid, malic acid, citric acid, tartaric acid, glycolic acid, gluconic acid, salicylic acid, 2-hydroxyisobutyric acid, glyceric acid, 2,2-bis(hydroxymethyl)propionic acid and 2,2-bis(hydroxymethyl)butyric acid; Carboxylic acids with a keto group (keto acids) such as pyruvic acid, acetoacetic acid, and levulinic acid; and Dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, glutaric acid, adipic acid and phthalic acid.

[0061] When an acid is used as the pH adjusting agent in the polishing agent disclosed herein, inorganic acids are preferred, and among these, nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid and their ammonium salts, sodium salts and potassium salts are preferred.

[0062] Examples of basic compounds include sodium hydroxide, potassium hydroxide, ammonium hydroxide, potassium carbonate, sodium carbonate and ammonium carbonate; and quaternary ammonium hydroxides such as tetramethylammonium hydroxide and tetraethylammonium hydroxide.

[0063] Other examples of amphoteric compounds include glycine, alanine, and phenylalanine.

[0064] Only one type of pH regulator may be used, or two or more types may be used in combination. To suppress the aggregation of abrasive grains and to further improve the selectivity ratio, the pH of the polishing compound disclosed herein is preferably 7 to 11, more preferably 8 to 10.5, and more preferably 8.5 to 10. The pH adjuster may be adjusted accordingly to achieve the aforementioned pH values. As an example, the pH adjuster may be 0.005 wt% to 2.0 wt%, more preferably 0.01 wt% to 1.5 wt%, and more preferably 0.01 wt% to 0.3 wt%, based on the total polishing compound described herein. (dispersant)

[0065] The polishing compound described herein may contain a dispersant to improve the dispersibility of the abrasive grains. Examples of dispersants include anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants. Only one type of dispersant may be used, or two or more types of dispersants may be used.

[0066] The anionic surfactant is preferably a polymer with a carboxyl group, an ammonium carboxylate or the like, and more preferably polyacrylic acid or polyacrylate.

[0067] Examples of cationic surfactants include a diallyldimethylammonium chloride polymer, a diallyldimethylammonium chloride / sulfur dioxide copolymer, a diallyldimethylammonium chloride / acrylamide copolymer, a diallyldimethylammonium chloride / maleic acid copolymer, and a maleic acid / diallyldimethylammonium ethyl sulfate / sulfur dioxide copolymer.

[0068] The weight-average molecular weight of the surfactant described above is preferably 10000 to 100000 in order to polish the surface to be polished at a higher speed.

[0069] If a dispersing agent is used, its content is preferably 0.0001 wt.% to 0.3 wt.%, more preferably 0.001 wt.% to 0.2 wt.% and even more preferably 0.01 wt.% to 0.15 wt.%, based on the total weight of the polishing agent, in order to polish the surface to be polished at a higher speed.

[0070] When the additives described above are used in the polishing compound disclosed herein, the additive content is preferably 0.01 to 10.0 wt.% and more preferably 0.01 to 5.0 wt.%, based on the total weight of the polishing compound.

[0071] The method for producing the polishing agent disclosed herein can be appropriately selected from methods in which abrasive grains, (bi)carbonate of amine or the like, and each of the components used as required are dispersed or dissolved uniformly in water, which is the medium.

[0072] For example, the polishing compound disclosed herein can be produced by separately preparing and mixing a dispersion fluid of abrasive grains and an additive solution for a polishing compound (which will be described later). According to this method, the storage stability of the dispersion fluid and the additive solution for a polishing compound described above is improved, and their transport is made easier.

[0073] Furthermore, (bi)carbonate of amine or the like can be added in a (bi)carbonate state or obtained by supplying carbon dioxide gas to a solution after the addition of amine or ammonium halide salt. [Additive solution for polishing agents]

[0074] The additive solution for the polishing compound according to this embodiment is an additive solution for preparing a polishing compound by mixing it with a dispersion fluid of abrasive grains, as described above. The additive solution for the polishing compound contains (bi)carbonate of a primary amine, a secondary amine, a tertiary amine, or a quaternary ammonium compound and water, and may optionally contain the additive described in relation to the aforementioned polishing compound. It should be noted that each of these components is as described above and therefore will not be explained in further detail here.

[0075] It should be noted that if a polishing compound is produced by separately preparing two liquids, i.e., a liquid in which abrasive grains are dispersed and an additive solution for a polishing compound, and subsequently mixing these together, it is possible to produce a liquid in which abrasive grains are dispersed at a concentration 2 to 100 times higher than a given concentration, and an additive solution for a polishing compound in which the concentration of (bi)carbonate is 2 to 100 times higher than a given concentration, and then to dilute these to the predetermined concentrations when using the polishing compound.More specifically, if, for example, the concentration of the abrasive grains in the dispersion liquid and the concentrations of the anionic polymer and the acidic compound in the additive solution are each ten times their respective determined concentrations, a polishing compound is obtained by mixing 10 parts by weight of the dispersion liquid, 10 parts by weight of the additive solution for a polishing compound and 80 parts by weight of water together and stirring the mixture.

[0076] By adding the above-described additive solution for polishing to the dispersion fluid of the abrasive grains, it is possible to obtain a polishing agent with high pH stability and stable grinding performance.

[0077] In the polishing additive solution described above, the content (concentration) of (bi)carbonate is preferably 0.001 to 30 wt.%, more preferably 0.01 to 20 wt.% and even more preferably 0.1 to 10 wt.%, based on the total additive solution.

[0078] Furthermore, the abrasive grain content in the above-described dispersion fluid is preferably 0.2 to 40 wt.%, more preferably 1 to 20 wt.% and even more preferably 5 to 10 wt.%. [Polishing process]

[0079] The polishing method according to the present disclosure is a method for polishing a surface to be polished of a semiconductor substrate containing silicon oxide by bringing a polishing pad into contact with the surface to be polished while a polishing agent is supplied in between, and polishing the surface to be polished by a relative movement of the surface to be polished and the polishing pad.

[0080] Examples of surfaces to be polished include a silicon dioxide surface of a semiconductor substrate, a blanket wafer in which a stopper film and a silicon dioxide film are laminated onto the surface of a semiconductor substrate, and a structured wafer in which these films are arranged in a pattern. Preferred examples of semiconductor substrates include a substrate for STI. The polishing agent according to the present disclosure is also effective for polishing to smooth an interlayer insulating film between multilayer wiring leads in the fabrication of semiconductor devices.

[0081] It should be noted that examples of materials for the stopper film include: compounds containing one or more of the elements selected from silicon, carbon, hafnium, zirconium, cobalt, ruthenium, molybdenum, titanium, tantalum, and copper; nitrides containing one or more of these; and oxides containing one or more of these. More specifically, examples include: a metal itself, such as copper, cobalt, ruthenium, molybdenum, titanium, and tantalum; a nitride, such as titanium nitride, tantalum nitride, and silicon nitride; an oxide, such as zirconium oxide and hafnium oxide; polysilicon, amorphous silicon, hafnium silicate, zirconium silicate, silicon carbide, and the like. Among these, silicon nitride or polysilicon are preferred to achieve a higher selectivity ratio.

[0082] Examples of silicon oxide films in substrates for STI include so-called PE-TEOS films, which are formed by a plasma CVD process using tetraethoxysilane (TEOS) as the starting material. Other examples of silicon oxide films include so-called HDP films, which are formed by a high-density plasma CVD process. In addition, HARP films and FCVD films, formed by other CVD processes, as well as SOD films formed by spin coating, can also be used. Examples of silicon nitride films include those formed by a low-pressure CVD process or a plasma CVD process using silane or dichlorosilane and ammonia as feedstocks, and those formed by an ALD process.Examples of polysilicon layers are those formed by a low-pressure CVD process or a plasma CVD process using silane as raw material and then converted into polycrystalline grains by heat treatment.

[0083] A known polishing device can be used for the polishing process according to the present disclosure. Fig. 2 is a schematic diagram showing an example of a polishing device. One in which in Fig. The polishing device 20 shown in Example 2 comprises a polishing head 22 holding a semiconductor substrate 21, such as an STI substrate, a polishing table 23, a polishing pad 24 connected to the surface of the polishing table 23, and a polishing agent supply line 26 through which a polishing agent 25 is supplied to the polishing pad 24. The polishing device 20 is configured to polish the surface to be polished of the semiconductor substrate 21 held by the polishing head 22 by bringing the surface to be polished into contact with the polishing pad 24 while the polishing agent 25 is supplied through the polishing agent supply line 26, and by rotating the polishing head 22 and the polishing table 23 relative to each other.

[0084] The polishing head 22 can perform not only rotary but also linear movements. Furthermore, the polishing table 23 and the polishing pad 24 can have sizes approximately equal to or smaller than those of the semiconductor substrate 21. In this case, it is preferred that the polishing head 22 and the polishing table 23 move relative to each other so that the entire surface of the semiconductor substrate 21 can be polished. Moreover, the polishing table 23 and the polishing pad 24 need not necessarily be rotary devices. That is, they can instead be moved in one direction, for example, by a belt or the like.

[0085] Although the polishing conditions of the polishing device 20 are not limited to specific conditions, it is possible to improve the material removal rate by applying a load to the polishing head 22, thereby pressing the polishing head 22 against the polishing pad 24 and increasing the polishing pressure exerted on it. The polishing pressure is preferably about 0.5 kPa to 50 kPa, and even more preferably about 3 kPa to 40 kPa, to ensure the uniformity and flatness of the surface of the semiconductor substrate 21 to be polished at the material removal rate and to avoid polishing defects such as scratches. The rotational speeds of the polishing table 23 and the polishing head 22 are preferably about 50 rpm to 500 rpm. Furthermore, the amount of polishing compound 25 to be supplied is adjusted appropriately according to the composition of the polishing compound, the polishing conditions described above, and the like.

[0086] The polishing pad 24 can be made of a non-woven fabric, a foamed polyurethane, a porous resin, a non-porous resin, or the like. To increase the supply of the polishing compound 25 to the polishing pad 24 or to retain a specific amount of the polishing compound 25 in the polishing pad 24, grooves in a grid pattern, a concentric circular pattern, a spiral pattern, or the like can be machined into the surface of the polishing pad 24. Furthermore, if required, a pad conditioner can be brought into contact with the surface of the polishing pad 24 so that the surface to be polished is polished while the surface of the polishing pad 24 is conditioned.

[0087] According to the polishing method as disclosed herein, it is possible to achieve a high selectivity ratio between the silicon oxide layer and the stop film while simultaneously suppressing polishing damage and performing polishing with high flatness. [Method for manufacturing a semiconductor component]

[0088] The method for producing a semiconductor component according to this embodiment is a method in which a semiconductor component is obtained by dividing a semiconductor substrate with a surface to be polished, which has been polished by the polishing method according to the present invention, into pieces.

[0089] The method for manufacturing a semiconductor component according to the present disclosure includes at least one division step in which a semiconductor substrate with a surface to be polished, which has been polished by the polishing process described above, is divided into pieces. The division step includes, for example, a step to obtain a semiconductor component, which is a semiconductor chip, by cutting the semiconductor substrate (e.g., a semiconductor wafer) by a known method such as blade cutting, laser cutting, or plasma cutting.

[0090] The process for manufacturing a semiconductor component can further include an interconnection step for joining another element to the surface of the semiconductor chip to be polished. This step results in a semiconductor component that is an assembly of components.

[0091] Examples of other elements include a second semiconductor chip and a rewiring layer. It should be noted that the second semiconductor chip may be a semiconductor chip obtained by the manufacturing process according to the present disclosure, or a semiconductor chip obtained by other processes. The interconnection step may, for example, be a step in which another element is placed directly on the surface to be polished and directly connected by fusion bonding, surface activation bonding, or the like, or a step in which the surface to be polished and another element are joined with an adhesive layer between them. Examples of the adhesive layer include an adhesive layer such as a solder layer and a copper layer, a glass layer, and a resin layer such as a polyimide layer and an epoxy layer.

[0092] The present disclosure may also provide an electronic device comprising at least one semiconductor component having a surface to be polished, which is polished by the polishing method according to the present disclosure. Examples

[0093] The present invention is described in more detail below with reference to examples and comparative examples, but is not limited to these examples. Examples 1 to 5 are examples according to the present disclosure, and examples 6 to 9 are comparative examples. [Measurement method] <ph>

[0094] The pH value was measured at a temperature of 25 ± 5 °C using a pH meter HM-30R from DKK-TOA Corporation. <durchschnittliche Sekundärteilchengröße>

[0095] The average secondary particle size was measured using a laser scattering / diffraction particle size meter (manufactured by HORIBA, Ltd., device name: LA-950). [Polishing compound]<Schleifkörner>

[0096] Cerium oxide particles with a particle size of 80 nm were used as abrasive grains. The cerium oxide content in the cerium oxide particles was 95 wt% or more. <(Bi)carbonate>

[0097] An aqueous solution of triethylamine, an aqueous solution of N-ethyldiethanolamine and an aqueous solution of N,N-dimethylpropan-1-amine were prepared and carbon dioxide gas was blown through each of these aqueous solutions for 30 to 60 minutes to obtain an aqueous (bi)carbonate solution of each amine. <Anfertigen von Poliermittel>

[0098] A specific quantity of polyacrylic acid was added to ultrapure water. The mixture was stirred using a mechanical stirrer and a magnetic stirrer until the liquid became transparent, indicating sufficient dissolution of the polyacrylic acid. A pH adjuster was then added until the desired pH was reached, and the mixture was stirred until the pH stabilized. A specific quantity of cerium dispersion liquid was then added and stirred, followed by a specific quantity of the aforementioned aqueous (bi)carbonate solution, again stirring. This resulted in polishing compounds (slurries) with the compositions and pH values ​​specified in Table 1 for Examples 1 to 8. The polishing compound shown in Example 9 was obtained by mixing the abrasive grains and water, adding the pH adjuster, and adjusting the pH to the value specified in Table 1. In Table 1, MEA stands for monoethanolamine. [Evaluation]<Bewertung von pH-Stabilität>

[0099] First, the pH of each of the polishing compounds from Examples 1 to 9 was measured immediately after preparation. Then, 500 g of each polishing compound was transferred to a 500 mL wide-mouth bottle called Eye Boy (manufactured by AS ONE Corporation), and the bottle was exposed to air for two weeks. The pH of the air-exposed slurry was measured, and its pH stability was assessed based on the magnitude of ΔpH, the difference between the pH of the slurry immediately after preparation and the pH of the air-exposed slurry. The smaller the ΔpH, the higher the pH stability. Table 1 shows the results. <geruchsbewertung>

[0100] The intensity of the odor was verified using a sensory test method employing the sense of smell. Table 1 shows the results. [Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Conditions abrasive grain Art Cerium oxide Cerium oxide Cerium oxide Cerium oxide Cerium oxide Particle size (nm) 80 80 80 80 80 Salary (mass %) 0,25 0,15 0,25 0,25 0,25 (Bi)carbonat Art Triethylamine carbonate Triethylamine carbonate Triethylamine carbonate N-Ethyldiethanolamine carbonate N,N-dimethylpropane-1-amine carbonate Molecular weight of carbonate 163,21 163,21 163,21 195,22 149,2 Boiling point (as amines) (°C) 89,7 89,7 89,7 249 66 Melting point (as amines) (°C) -114,7 -114,7 -114,7 -50 -115,88 Solubility (as amine) (g / L) 112,4 112,4 112,4 ∞ ∞ pKa (of conjugated acid) 10,75 10,75 10,75 8,6 9,83 Concentration (mmol / L) 12,3 36,8 61,3 50,6 50,6 Salary (mass %) 0,20 0,60 1,00 0,99 0,75 pH adjuster Art MEA MEA MEA N-Ethyldiethanolamine N,N-Dimethylpropan-1-amine pH 9,30 9,40 9,30 9,30 9,30 Results ΔpH 0,28 0,25 0,20 0,10 0,18 Odor no no no no no Example 6 Example 7 Example 8 Example 9 Conditions abrasive grain Art Cerium oxide Cerium oxide Cerium oxide Cerium oxide Particle size (nm) 80 80 80 80 Salary (mass%) 0,25 0,25 0,25 0,25 (Bi)carbonat Art Ammonium hydrogen carbonate Ammonium hydrogen carbonate Ammonium hydrogen carbonate none Molecular weight of carbonate 79,056 79,056 79,056 - Boiling point (as amine) (°C) -33,34 -33,34 -33,34 - Melting point (as amine) (°C) -77,73 -77,73 -77,73 - Solubility (as amine) (g / L) 899 899 899 - pKa (of conjugated acid) 9,25 9,25 9,25 - Concentration (mmol / L) 41,7 12,6 50,6 - pH adjuster Art MEA MEA MEA MEA pH 9,50 9,00 9,00 9,50 Results ΔpH 0,33 0,23 0,01 1,30 Odor Yes Yes Yes no

[0101] As shown in Table 1, it has been confirmed that the polishing agents of Examples 1 to 5, which contain (bi)carbonate of a certain amine or the like, exhibit excellent stability in a pH range of 7 to 11, suppress odor, and thus suppress the volatility of ammonia. By using the polishing agent disclosed herein, in which the volatility of ammonia is suppressed, impurities, corrosion, and the like of the polishing device can be suppressed. The carbonates of Examples 6 to 8, which use ammonium bicarbonate, a (bi)carbonate of ammonium ions (NH4), + ) is, an odor was produced and the volatility of ammonia was confirmed. [Polishing test]

[0102] Next, a polishing test was performed on the polishing compound in Example 2. <poliertestverfahren>

[0103] The polishing compound's performance was evaluated using a fully automatic CMP device, the FREX300X (manufactured by EBARA CORPORATION). A polyurethane pad (IC-1000, manufactured by DuPont) was used as the polishing pad, and a diamond pad conditioner (manufactured by 3M, product name: A165) was used to condition the pad. The polishing conditions were as follows: polishing pressure 2 psi, polishing table speed 80 rpm, and polishing head speed 81 rpm. The polishing compound feed rate was 250 mL / min.

[0104] Each of the following objects was used as the polishing object (object to be polished). -Silicon oxide film: a blanket wafer with a silicon dioxide film formed by a plasma CVD process using tetraethoxysilane (TEOS) as raw material on a 12-inch silicon substrate -Polysilicon film: a blanket wafer with a polysilicon film obtained by heat treatment at 600 °C on a film formed by a low-pressure CVD process using silane as raw material on a 12-inch silicon substrate -Silicon nitride film: a blanket wafer with a silicon nitride film formed by a low-pressure CVD process using silane and ammonia as raw materials on a 12-inch silicon substrate <beweretungsverfahren>

[0105] A SCREEN Holdings Co., Ltd. VM-3210 film thickness gauge was used to measure the thickness of the individual films. For each blanket wafer, the removal rate was calculated by determining the difference between the layer thickness before polishing and the layer thickness after one minute of polishing. The mean (Å / min) of the removal rates measured at 49 points on the substrate surface was defined as the removal rate.

[0106] The results of the aforementioned polishing test are listed below. -Silicon oxide layer removal rate: 1300 Å / min -Polysilicon removal rate: 2800 Å / min -Silicon oxide film removal rate: 300 Å / min

[0107] The results mentioned above demonstrate that the polishing compound described herein exhibits excellent polishing performance on oxide layers and polysilicon, and a high selectivity ratio between oxide and nitride layers. Furthermore, the polishing compound described herein is also suitable for polishing precious metals such as Ru, Mo, and Co, as well as metals containing Cu and the like. Industrial applicability

[0108] According to the present invention, for example, high-speed polishing can be carried out in a CMP of a surface to be polished which includes an insulating film. Therefore, a polishing method according to the present disclosure is suitable for polishing an insulating film for STI in the manufacture of semiconductor devices.

[0109] This application is based on Japanese patent application No. 2023-112030, filed on July 7, 2023, the disclosure of which is hereby incorporated in its entirety by reference, and claims its priority. List of reference symbols

[0110] 1...Silicon substrate, 2...Stopper film, 3...Trench, 4...Silicon film, 20...Polishing device, 21...Semiconductor substrate, 22...Polishing head, 23...Polishing table, 24...Polishing pad, 25...Polishing compound, 26...Polishing compound supply line QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2016-154208

[0006] JP 2023-112030

[0109] < / beweretungsverfahren> < / poliertestverfahren> < / geruchsbewertung> < / ph> < / additiv> < / wasser>

Claims

[1] Polishing compound containing: Abrasive grains; and (Bi)carbonate of a primary amine, a secondary amine, a tertiary amine or a quaternary ammonium, and water, wherein an organic group that contains the amine or the ammonium, a group that is selected from a linear alkyl group, a branched alkyl group and an alkanol group, a (bi)carbonate content of 5 mmol / L to 130 mmol / L, based on the total polishing agent, is, a boiling point of the amine or ammonium is 0 °C to 500 °C, and the pH value is between 7 and 11. [2] The polishing agent according to claim 1, wherein the molecular weight of the (bi)carbonate is 500 or less. [3] Polishing agent according to claim 1, wherein the melting point of the amine or the ammonium is -180 °C to 0 °C. [4] Polishing agent according to claim 1, wherein an absolute value of a difference between the pKa value of ammonium ions in the (bi)carbonate and the pH value of the polishing agent is 3 or less. [5] Polishing agent according to claim 1, wherein the organic group comprises an alkanol group. [6] Polishing agent according to claim 1, wherein the (bi)carbonate comprises (bi)carbonate of a tertiary amine. [7] Polishing composition according to claim 1, wherein the abrasive grains comprise at least one type selected from the group consisting of silica particles, aluminium oxide particles, zirconium oxide particles, cerium compound particles, titanium oxide particles, germanium oxide particles, composite particles thereof and core-shell particles. [8] Polishing composition according to claim 2, wherein the abrasive grains contain cerium compound particles. [9] Polishing composition according to claim 2, wherein the abrasive grains contain cerium oxide particles. [10] Polishing compound according to claim 1, wherein the abrasive grain content is 0.01 wt.% to 10.0 wt.%, based on the total weight of the polishing compound. [11] Polishing method in which a polishing pad is brought into contact with a surface of a semiconductor substrate to be polished, while a polishing agent is supplied between them, and the surface to be polished is polished by a relative movement of the surface to be polished and the polishing pad, wherein the polishing agent is the polishing agent according to any one of claims 1 to 10. [12] Method for producing a semiconductor component, wherein the semiconductor component is obtained by dividing a semiconductor substrate having a surface to be polished which has been polished by the polishing method according to claim 11 into pieces. [13] Additive solution for a polishing agent containing (bi)carbonate of a primary amine, a secondary amine, a tertiary amine or a quaternary ammonium, and water, wherein an organic group comprising the amine or the ammonium is a group selected from a linear alkyl group, a branched alkyl group and an alkanol group. [14] Method for producing the additive solution for the polishing agent according to claim 13, wherein the method comprises: Dissolving a primary amine, a secondary amine, a tertiary amine, or a quaternary ammonium salt in water; and Adding carbon dioxide gas to the water to produce (bi)carbonate.

Images