Polishing agent composition and polishing method using polishing agent composition

Abstract

The invention relates to a polishing agent composition and a polishing method using the polishing agent composition. Provided is a polishing agent composition which is capable of improving the smoothness and flatness of the wafer surface of a semiconductor wafer after mirror polishing while increasing the speed of mirror polishing such as polishing speed, is capable of mirror finishing with high processing precision, and has excellent storage stability. A polishing agent composition for polishing an object to be polished that contains a group III-V compound as a constituent component, the polishing agent composition being provided with colloidal silica, an oxidizing agent, and an oxidation accelerator, the polishing agent composition being for promoting an oxidation reaction of the surface of the object to be polished by means of the oxidizing agent; a stabilizer for controlling an effect of promoting an oxidation reaction on the surface of the object to be polished by means of the oxidation accelerator; and water.

Description

[0001] This application is a divisional application of the Chinese invention patent application with application number: 202180059750.4, application date: July 9, 2021, and invention name: "Abrasive composition and polishing method using abrasive composition". Technical Field

[0002] The present invention relates to an abrasive composition and a polishing method using the abrasive composition. More specifically, the present invention relates to an abrasive composition for mirror-polishing the surface of a compound semiconductor wafer containing a Group III-V compound such as gallium arsenide (GaAs), indium phosphide (InP), gallium phosphide (GaP), and gallium nitride (GaN), as the polishing object, and a polishing method using the abrasive composition. Background Art

[0003] Conventionally, compound semiconductor wafers (hereinafter referred to as "semiconductor wafers") containing III-V compounds such as GaAs, InP, GaP, and GaN as components have been widely used as substrates or components for various semiconductor devices such as semiconductor lasers, light-emitting diodes, optical modulators, light-detecting elements, and solar cells. In recent years, demand for these wafers has increased significantly due to the widespread use of various electronic devices.

[0004] Semiconductor wafers are generally thinned by growing a single crystal of a III-V compound, lapping, etching, polishing, and other processing steps, and then finally polishing to complete the finishing process.

[0005] Final polishing, which corresponds to the final process (finishing process) of semiconductor wafers, is a process for smoothing the wafer surface of the semiconductor wafer and finishing it to a mirror surface. For example, a polishing pad is mounted on a rotatable circular platform, and a pre-prepared polishing liquid is dripped onto the pad surface (polishing surface) of the polishing pad while the semiconductor wafer to be polished is pressed against the pad surface while the polishing pad is rotated, thereby polishing the wafer surface by chemical and mechanical action.

[0006] Conventionally, semiconductor wafer polishing is performed in two stages: primary polishing (rough polishing) and secondary polishing (mirror finish polishing). For example, known methods include a method in which, during primary polishing of semiconductor wafers, polishing is first performed using abrasive particles with a large particle size, followed by polishing using abrasive particles with a small particle size (see Patent Document 1); a polishing method using an abrasive with a characteristic particle shape and particle size distribution, particularly sodium dichloroisocyanurate as an oxidizing agent (see Patent Document 2); and a polishing method in which, during primary polishing of GaAs wafers, different polishing slurries are used in the front and back stages of polishing (see Patent Document 3). Various methods are employed to achieve high-precision mirror finishes on the wafer surfaces of semiconductor wafers.

[0007] In particular, after mirror polishing a semiconductor wafer, further layers are formed on the mirror surface through epitaxial growth. Therefore, the mirror polishing accuracy (finishing accuracy) of the final polishing is extremely important, requiring a wafer surface with minimal unevenness, excellent smoothness and flatness, minimal undulations, and few surface abnormalities such as pits.

[0008] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Laid-Open No. 2002-18705 Patent Document 2: Japanese Patent Application Laid-Open No. 2005-264057 Patent Document 3: Japanese Patent Application Laid-Open No. 2008-198724 Summary of the Invention

[0009] Problems to be solved by the invention However, the polishing methods and polishing slurries (polishing compositions) used in Patent Documents 1 to 3 described above sometimes require long processing times, making it difficult to expedite the polishing process, or failing to fully achieve the required mirror polishing accuracy. Furthermore, the use of sodium dichloroisocyanurate as an oxidizing agent, as disclosed in Patent Documents 2 and 3, significantly impacts the storage stability of the polishing slurry itself, resulting in a tendency for the polishing rate to decrease over time, making it difficult to use for extended periods.

[0010] Therefore, in view of the above-mentioned circumstances, the present invention aims to provide an abrasive composition that can achieve a high-precision mirror finish by increasing the polishing speed and other aspects of the mirror polishing process, and improve the smoothness and flatness of the wafer surface of the mirror-polished semiconductor wafer, and has excellent storage stability, as well as a polishing method using the abrasive composition.

[0011] Means for solving problems The inventors of the present application conducted intensive studies to solve the above-mentioned problems and found that the mirror polishing process of semiconductor wafers can be accelerated by polishing using an abrasive composition prepared containing specific components, thereby completing the present invention described below.

[0012] [1] An abrasive composition for polishing an object containing a Group III-V compound as a constituent, comprising colloidal silica; an oxidizing agent; an oxidation accelerator for promoting an oxidation reaction on the surface of the object to be polished by the oxidizing agent; a stabilizer for controlling the promoting effect of the oxidation reaction on the surface of the object to be polished by the oxidation accelerator; and water.

[0013] [2] The abrasive composition according to [1] above, wherein the Group III-V compound is at least one selected from gallium arsenide, gallium phosphide, indium phosphide, indium arsenide, aluminum arsenide, indium-gallium-arsenic compounds, indium-gallium-phosphorus compounds, aluminum-gallium-arsenic compounds, indium-aluminum-gallium-arsenic compounds, gallium nitride, gallium-antimony compounds, and indium-antimony compounds.

[0014] [3] The polishing compound according to [1] or [2] above, wherein the oxidizing agent is a peroxide, permanganic acid or a salt thereof, chromic acid or a salt thereof, a peroxy acid or a salt thereof, a halogen oxyacid or a salt thereof, an oxyacid or a salt thereof, or a mixture thereof.

[0015] [4] The polishing compound according to any one of [1] to [3] above, wherein the oxidizing agent is hydrogen peroxide.

[0016] [5] The polishing compound according to any one of [1] to [4] above, wherein the oxidation promoter is any one of an inorganic acid metal salt and an organic acid metal salt.

[0017] [6] The polishing compound according to [5] above, wherein the inorganic acid metal salt is either ferric nitrate or ferric sulfate.

[0018] [7] The polishing compound according to any one of [1] to [6] above, wherein the stabilizer is at least one selected from phosphoric acid, phosphorous acid, organic phosphonic acid, polycarboxylic acid, and polyaminocarboxylic acid.

[0019] [8] The polishing compound according to [7] above, wherein the polycarboxylic acid is malonic acid or citric acid.

[0020] [9] The polishing compound according to any one of [1] to [8] above, wherein the pH (25° C.) is in the range of 0.1 to 6.0.

[0021]

[10] A polishing method using an abrasive composition, wherein the polishing method comprises polishing an object to be polished containing a Group III-V compound as a constituent component using the abrasive composition according to any one of [1] to [9].

[0022] Effects of the Invention The polishing composition of the present invention is characterized by containing an oxidizing agent, an oxidation accelerator, and a stabilizer. By using the polishing composition to polish a semiconductor wafer in a polishing method using the polishing composition of the present invention, a mirror polishing process with excellent flatness and smoothness can be performed at a high polishing rate. Furthermore, the polishing composition can also exhibit excellent long-term storage stability. DETAILED DESCRIPTION

[0023] The following describes embodiments of the present invention. The present invention is not limited to the following embodiments, and changes, corrections, and improvements can be made without departing from the scope of the invention.

[0024] 1. Abrasive composition An abrasive composition according to one embodiment of the present invention contains colloidal silica, an oxidizing agent, an oxidation accelerator, a stabilizer, and water, with these materials prepared in a specific ratio. The abrasive composition according to this embodiment exhibits excellent storage stability, but after preparation, it is preferably used for polishing semiconductor wafers such as GaAs wafers, InP wafers, GaP wafers, and GaN wafers promptly. For example, it is preferably used for polishing within 48 hours of preparation, and more preferably within 24 hours of preparation.

[0025] 1.1 Colloidal Silica The average particle size (D50) of the colloidal silica used as a material in the polishing composition of this embodiment is preferably in the range of 10 to 200 nm, and more preferably in the range of 20 to 100 nm. If the average particle size (D50) of the colloidal silica is less than 10 nm, the polishing resistance between the substrate and the polishing pad during polishing increases, and polishing may not proceed smoothly. If the average particle size (D50) of the colloidal silica exceeds 200 nm, scratches may occur on the substrate. The average particle size (D50) of the colloidal silica is analyzed and calculated based on the results of transmission electron microscopy (TEM) observation (details will be described later).

[0026] Colloidal silica is known to have shapes such as spheres, candy-shaped particles (granules with convex portions on the surface), and irregular shapes. Primary particles are monodispersed in water to form a colloidal state. Colloidal silica of various shapes can be used as a material for the polishing composition of this embodiment.

[0027] The colloidal silica used as a material can be produced by conventionally known methods, such as the water glass method, which uses an alkali metal silicate such as sodium silicate or potassium silicate as a raw material and causes a condensation reaction in an aqueous solution to grow colloidal silica particles; the alkoxysilane method, which uses a tetraalkoxysilane such as tetraethoxysilane as a raw material and causes a condensation reaction in a solvent containing a water-soluble organic solvent such as an alcohol by hydrolysis using an acid or base to grow colloidal silica particles; or the method of synthesizing colloidal silica by reacting metallic silicon with water in the presence of an alkaline catalyst. It should be noted that the water glass method is preferably used in terms of production cost. These synthesis methods can be appropriately used to produce the colloidal silica used as a material for the polishing composition of this embodiment.

[0028] In the polishing composition of this embodiment, the colloidal silica content (content ratio) is preferably in the range of 1 to 50 mass%, more preferably 2 to 40 mass%. If the colloidal silica content is less than 1 mass%, the polishing resistance between the substrate and the polishing pad during polishing increases, potentially preventing smooth polishing. If the colloidal silica content exceeds 50 mass%, the colloidal silica may easily gel.

[0029] 1.2 Oxidants The oxidizing agent used as a material of the polishing composition of this embodiment may be peroxide, permanganic acid or its salts, chromic acid or its salts, peroxy acid or its salts, halogen oxyacid or its salts, oxyacid or its salts, or a mixture of two or more thereof.

[0030] More specifically, examples include hydrogen peroxide, sodium peroxide, barium peroxide, potassium peroxide, potassium permanganate, metal salts of chromic acid, metal salts of dichromic acid, persulfuric acid, sodium persulfate, potassium persulfate, ammonium persulfate, peroxyphosphoric acid, sodium peroxoborate, performic acid, peracetic acid, hypochlorous acid, sodium hypochlorite, and calcium hypochlorite. In particular, hydrogen peroxide, persulfuric acid and its salts, and hypochlorous acid and its salts are preferably used, and hydrogen peroxide is even more preferably used.

[0031] The oxidizing agent oxidizes the surface of semiconductor wafers, such as GaAs wafers, to form an oxide layer, facilitating the polishing of the semiconductor wafer. Furthermore, it oxidizes grinding debris, such as arsenic compounds, generated and discharged during polishing of the semiconductor wafer, thereby suppressing degradation of the working environment.

[0032] In the polishing composition of this embodiment, the content (content ratio) of the oxidizing agent in the polishing composition is preferably in the range of 0.01 to 10.0 mass%, more preferably 0.1 to 5.0 mass%. If the oxidizing agent content is less than 0.01 mass%, the polishing rate may decrease. If the oxidizing agent content exceeds 10.0 mass%, the surface roughness of the polished substrate may deteriorate.

[0033] 1.3 Oxidation accelerators The oxidation accelerator used as a material of the polishing composition of this embodiment can be an inorganic acid metal salt or an organic acid metal salt. In particular, an inorganic acid metal salt is preferably used.

[0034] More specifically, inorganic acid metal salts include iron salts, copper salts, silver salts, and manganese salts of nitric acid, sulfuric acid, hydrochloric acid, and phosphoric acid. For example, iron (III) nitrate, iron (III) sulfate, ferrous (II) sulfate, iron (III) chloride, or ferrous (II) chloride are preferred, with iron (III) nitrate being particularly preferred. These inorganic acid metal salts may be used in either anhydrous or hydrated form.

[0035] Examples of organic acid metal salts include metal salts of polycarboxylic acids and metal salts of polyaminocarboxylic acids. More specifically, metal salts of polycarboxylic acids include metal salts of oxalic acid, malonic acid, succinic acid, maleic acid, phthalic acid, and citric acid. Examples of metal salts of polyaminocarboxylic acids include metal salts of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminediacetic acid, and triethylenetetraaminehexaacetic acid. Iron salts, copper salts, silver salts, and manganese salts of these organic acids can also be used.

[0036] The oxidation accelerator has the function of accelerating the oxidation reaction of the semiconductor wafer caused by the oxidizing agent, thereby achieving an effect of facilitating the polishing of the semiconductor wafer.

[0037] In the polishing composition of this embodiment, the content (content ratio) of the oxidizing agent contained in the polishing composition is preferably in the range of 0.01 to 10.0 mass%, more preferably 0.02 to 5.0 mass%. If the content of the oxidizing agent is less than 0.01 mass%, the polishing rate decreases, and the surface roughness of the polished substrate may deteriorate. Even if the content of the oxidizing agent exceeds 10.0 mass%, the effect of the oxidizing agent reaches its limit, which is economically disadvantageous.

[0038] 1.4 Stabilizer The stabilizer used as a material in the polishing compound of this embodiment can be at least one selected from phosphoric acid, phosphorous acid, organic phosphonic acid, polycarboxylic acid, or polyaminocarboxylic acid. Specific examples of polycarboxylic acids include oxalic acid, malonic acid, succinic acid, maleic acid, phthalic acid, and citric acid. Furthermore, specific examples of polyaminocarboxylic acids include ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminediacetic acid, and triethylenetetraaminehexaacetic acid. Alkali metal salts thereof may also be used.

[0039] On the other hand, specific examples of the organic phosphonic acid include 2-aminoethylphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotris(methylenephosphonic acid), ethylenediaminetetra(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, ethane-1-hydroxy-1,1,2-triphosphonic acid, ethane-1,2-dicarboxy-1,2-diphosphonic acid, methanehydroxyphosphonic acid, 2-phosphonobutane-1,2-dicarboxylic acid, 1-phosphonobutane-2,3,4-tricarboxylic acid, and α-methylphosphonosuccinic acid.

[0040] Among the above, phosphoric acid, 1-hydroxyethylidene-1,1-diphosphonic acid, malonic acid or citric acid is preferably used, and malonic acid or citric acid is more preferably used.

[0041] The stabilizer controls the effect of the oxidation accelerator on the semiconductor wafer's oxidation reaction. This allows the oxidation reaction to proceed in a controlled manner. Therefore, after the abrasive composition is prepared, the oxidation reaction on the surface of the object being polished can proceed slowly. As a result, the abrasive composition can exert its effects over a long period of time, maintaining its storage stability. This ensures that the polishing of semiconductor wafers proceeds smoothly and stably over a long period of time.

[0042] In the polishing composition of this embodiment, the content (content ratio) of the stabilizer contained in the polishing composition is preferably in the range of 0.01 to 10.0 mass %, more preferably 0.02 to 5.0 mass %. If the content of the stabilizer is less than 0.01 mass %, bubbles may be generated during preparation of the polishing composition, and the stability of the polishing composition over time may be deteriorated. Even if the content of the stabilizer exceeds 10.0 mass %, the effect of the stabilizer reaches its limit, which is economically disadvantageous.

[0043] 1.5 Water The water used as a material for the polishing composition of the present embodiment is not particularly limited as long as it is pure water, ultrapure water, or distilled water, etc., from which ions and suspended matter have been removed.

[0044] 1.6 Physical Properties of Abrasive Compositions In the polishing composition of this embodiment, the pH (25°C) value is preferably in the range of 0.1 to 6.0, and more preferably in the range of 0.5 to 5.0. It should be noted that the pH value of the polishing composition can be adjusted according to the content of the oxidizing agent and the stabilizer. Furthermore, in order to adjust the pH value, an acidic compound or a basic compound may be appropriately added. When the pH (25°C) value of the polishing composition is less than 0.1, it may easily cause corrosion of the polishing machine and surrounding equipment. If the pH (25°C) value of the polishing composition exceeds 6.0, the colloidal silica is likely to gel, and the surface roughness of the polished substrate may be deteriorated.

[0045] 2. Grinding object The semiconductor wafer to be polished using the polishing composition of this embodiment contains a Group III-V compound as a component and is obtained by thinly slicing the previously described gallium arsenide (GaAs) and indium phosphide (InP). The Group III-V compound is selected from the group consisting of gallium phosphide (GaP), indium arsenide (InAs), aluminum arsenide (AlAs), indium gallium arsenic compounds (InGaAs), indium gallium arsenic phosphide compounds (InGaAsP), aluminum gallium arsenic compounds (AlGaAs), indium aluminum gallium arsenic compounds (InAlGaAs), gallium nitride (GaN), gallium antimony compounds (GaSb), and indium antimony compounds (InSb). A semiconductor wafer (Group III-V compound semiconductor wafer) containing at least one of these Group III-V compounds as a component is formed.

[0046] 3. Polishing method using abrasive composition A polishing method using the polishing composition of one embodiment of the present invention (hereinafter referred to as the "polishing method") is carried out by polishing a semiconductor wafer containing a Group III-V compound as a polishing object using the polishing composition of this embodiment. The polishing method comprises two stages (processes): a primary polishing step and a secondary polishing step performed after the primary polishing step, and both stages have the properties of chemical polishing and mechanical polishing.

[0047] The primary polishing process in the lapping method is primarily aimed at increasing the polishing speed during the lapping process, in other words, improving the efficiency of the lapping process, and ensuring the flatness of the semiconductor wafer. Therefore, mechanical polishing is a relatively high factor. On the other hand, secondary polishing is primarily aimed at final finishing of the semiconductor wafer surface to a mirror finish, removing surface scratches (scratches), haze, and processing strain, resulting in a perfect mirror finish. Therefore, chemical polishing is a relatively high factor.

[0048] Here, during secondary polishing, the goal is to achieve a perfect mirror finish, and a two-layer structure is often used, for example, with a base layer comprising polyester fibers disposed on a polishing pad and a polyurethane foam surface layer disposed on the base layer. Furthermore, after the secondary polishing, an etching process may be performed to remove residual deposits on the semiconductor wafer surface and an oxide film on the wafer surface, and a film formation step may be performed to form a film on the wafer surface by epitaxial growth. The abrasive composition of this embodiment can be used when applying the polishing method of this embodiment to semiconductor wafers, and can be employed at any stage (step) of the primary polishing or secondary polishing process described above.

[0049] It should be noted that, while the polishing pad described above illustrates a two-layer structure comprising a base layer composed of polyester fiber and a polyurethane foam surface layer for secondary polishing, this is not limiting and conventionally known polishing pads comprising non-woven fabrics, polyurethane foam, porous resins, and non-porous resins may be appropriately selected and used. Furthermore, to facilitate the supply of the polishing composition to the polishing pad or to retain a certain amount of the polishing composition on the polishing pad, the surface of the polishing pad may be grooved in a grid, concentric, or spiral pattern.

[0050] [Example] Below, the present invention is further described in detail based on embodiment, but the present invention is not limited to these embodiment.In addition, in the present invention, except following embodiment, in the scope that does not depart from the gist of the present invention, can apply various changes, improvement based on the knowledge of those skilled in the art.

[0051] (Preparation of Abrasive Composition) The polishing compositions of Examples 1 to 17 and Comparative Examples 1 to 11 were prepared by mixing the materials listed in Table 1 below so that the contents (mass %) listed in Table 1 were included. The polishing compositions of Examples 1, 12, 14, and 16 were identical, as were the polishing compositions of Examples 4, 13, 15, and 17, as were the polishing compositions of Comparative Examples 1, 6, 8, and 10, and the polishing compositions of Comparative Examples 4, 7, 9, and 11. The polishing compositions of Examples 1 to 10, 12 to 17, and Comparative Examples 4, 7, 9, and 11 were used in polishing tests immediately after preparation. However, the polishing compositions of Comparative Examples 1 to 3, 6, 8, and 10 generated bubbles after preparation and were therefore used in polishing tests after the bubble generation ceased. Furthermore, the polishing composition of Example 11 was subjected to the polishing test 2 hours after being prepared as the polishing composition, while the polishing composition of Comparative Example 5 generated bubbles after being prepared as the polishing composition and was therefore subjected to the polishing test 2 hours after the generation of bubbles ceased.

[0052] Note that the polishing composition was prepared so that the stabilizer content in mol% remained constant, so the mass % values ​​in Tables 1 to 6 reflect the molecular weight of each compound. Furthermore, "HEDP" in Tables 1 and 2 stands for 1-hydroxyethylidene-1,1-diphosphonic acid, EDTA stands for ethylenediaminetetraacetic acid, and EDTA-iron stands for ethylenediaminetetraacetic acid iron.

[0053] [Table 1]

[0054] (Colloidal silica particle size) The particle size (Heywood diameter) of colloidal silica is measured as the Heywood diameter (projected area equivalent circle diameter) by analyzing a photograph of the field of view at 100,000x magnification using a transmission electron microscope (TEM) (JEOL Ltd., JEM2000FX (200 kV)). The photograph is analyzed using analysis software (Mountech Co., Ltd., Mac-View Ver. 4.0). The average particle size of colloidal silica is calculated by analyzing the sizes of approximately 2,000 colloidal silica particles using the above method and calculating the average particle size (D50) at the 50% cumulative particle size distribution (cumulative volume basis) on the smaller particle size side using the same analysis software (Mountech Co., Ltd., Mac-View Ver. 4.0).

[0055] (1) Polishing of GaAs substrate The polishing conditions for the polishing test of the polishing object using the polishing compositions prepared as Examples 1 to 11 and Comparative Examples 1 to 5 are as follows. The results of the polishing test under these polishing conditions are shown in Tables 2 and 3 below.

[0056] (GaAs substrate polishing conditions) Grinding device: Single-sided grinding machine platform diameter 350mm Polishing object: 3-inch GaAs substrate Polishing pad: Hard polyurethane IC1400 grooved Grinding pressure: 200g / cm 2 Platform speed: 60rpm Grinding time: 10min Abrasive composition supply: 1-way supply, flow rate 40 ml / min (GaAs substrate polishing speed ratio) The weight of a 3-inch GaAs substrate (hereinafter referred to as the "GaAs substrate") being polished was measured before and after the polishing test, and the polishing rate was calculated from the weight difference. The polishing rate ratio is expressed as a relative value relative to the polishing rate of Comparative Example 1, which is set to 1 (baseline). A larger polishing rate ratio indicates a higher polishing rate and higher productivity.

[0057] (State of the substrate surface of the GaAs substrate) The surface of the GaAs substrate after the polishing test was observed visually and with a scanning white interference microscope (VS-1540 manufactured by Hitachi High-Tech Science Corporation).

[0058] (Substrate surface roughness (Sa) of GaAs substrate) The surface roughness (Sa) of the surface of the GaAs substrate after the polishing test was measured using the aforementioned scanning white interference microscope in a measurement range of 102 μm×102 μm.

[0059] [Table 2]

[0060] (Investigation on GaAs substrates) As shown in Table 2, the polishing composition of Comparative Example 1 does not contain a stabilizer, which is an essential component of the polishing composition of the present invention. Therefore, a large amount of bubbles were generated immediately after the polishing composition was prepared. Although this was difficult to handle in practice, the aforementioned performance evaluation was performed on the polishing composition after preparation. Note that the polishing test itself was performed after bubble generation ceased.

[0061] As shown in the results in Table 2, the polishing rate of the polishing composition of Comparative Example 1 was less than half that of the polishing rate of the polishing compositions of Examples 1 to 4, and the substrate surface roughness (Sa) was significantly worse than that of the polishing compositions of Examples 1 to 4. Furthermore, while gloss was observed in the central portion of the substrate surface, haze occurred in the peripheral portion of the substrate. Furthermore, numerous visible scratches were observed.

[0062] As shown in Table 2, the polishing composition of Comparative Example 2 used nitric acid instead of the stabilizer used in the polishing compositions of Examples 1 to 4, which are the polishing compositions of the present invention. Therefore, a large amount of bubbles were generated immediately after the polishing composition was prepared. Although this was difficult to handle from a practical perspective, the aforementioned performance evaluation was performed on the polishing composition after preparation. The polishing test itself was performed after bubble generation ceased.

[0063] As shown in the results in Table 2, the polishing rate of the polishing composition of Comparative Example 2 was lower than that of the polishing compositions of Examples 1 to 4. Meanwhile, the substrate surface roughness and substrate surface condition were both good. As mentioned above, a large amount of bubbles were generated immediately after preparation, so the storage stability of the polishing composition was evaluated as follows. The results are shown in Table 3.

[0064] [Table 3]

[0065] As shown in the results in Table 3, Comparative Example 5, which was subjected to a polishing test 2 hours after the cessation of bubble generation after preparation, showed that the polishing rate was reduced to half compared to Comparative Example 2, where polishing was performed immediately after the cessation of bubble generation. This indicates a lack of storage stability. On the other hand, Example 11, which was subjected to a polishing test 2 hours after preparation, showed polishing performance comparable to that of the polishing composition of Example 4 and exhibited excellent storage stability.

[0066] As shown in the results of Table 2, the polishing composition of Comparative Example 3 uses acetic acid instead of the stabilizer used in the polishing compositions of Examples 1 to 4 of the present invention. Although gloss was observed on the substrate surface after the polishing test, numerous scratches were visually observed, and the surface roughness value was significantly deteriorated. In contrast, in Examples 1 to 4, which meet the requirements of the polishing composition of the present invention, gloss was observed on the substrate surface after the polishing test, no scratches were visually observed, and the surface roughness value was significantly improved compared to Comparative Example 3.

[0067] As shown in the results of Table 2, the polishing composition of Comparative Example 4 is an example in which the oxidation accelerator, an essential component of the polishing composition of the present invention, is not included. The polishing compositions of Examples 4 to 7 corresponding to Comparative Example 4 exhibited low polishing rates, haze was observed on the substrate surface after the polishing test, and significantly reduced surface roughness. In contrast, Examples 4 to 7, which possess the requirements of the polishing composition of the present invention, exhibited improved polishing rates, glossiness, and good surface roughness on the substrate surface after the polishing test.

[0068] The polishing composition of Example 8 had a higher content (concentration) of colloidal silica compared to the polishing composition of Example 4. The polishing composition of Example 9 had a higher content (concentration) of hydrogen peroxide as an oxidizing agent compared to the polishing composition of Example 4. The polishing composition of Example 10 had a higher content (concentration) of an oxidizing accelerator compared to the polishing composition of Example 4. All of these polishing compositions of Examples 8 to 10 exhibited excellent polishing performance.

[0069] (2) Polishing of InP substrate The polishing conditions for the polishing test of the polishing object using the polishing compositions prepared as Examples 12 and 13 and Comparative Examples 6 and 7 are as follows. The results of the polishing test conducted under these polishing conditions are shown in Table 4 below.

[0070] (Polishing conditions for InP substrates) Grinding device: Single-sided grinding machine platform diameter 360mm Polishing object: 2-inch InP substrate Abrasive pad: Non-woven SUBA800 without groove Grinding pressure: 200g / cm 2 Platform speed: 60rpm Grinding time: 20min Abrasive composition supply: circulation, flow rate 200ml / min (Polishing speed ratio of InP substrate) The weight of a 2-inch InP substrate (hereinafter referred to as the "InP substrate") being polished was measured before and after the polishing test, and the polishing rate was calculated from the weight difference. The polishing rate ratio is expressed as a relative value, with the value of Comparative Example 6 set to 1 (baseline). A larger polishing rate ratio indicates a higher polishing rate and higher productivity.

[0071] (State of the substrate surface of the InP substrate and substrate surface roughness (Sa) of the InP substrate) The substrate surface condition and substrate surface roughness (Sa) were measured using the same method as for the GaAs substrate.

[0072] [Table 4]

[0073] (Inspection of InP substrate) As shown in Table 4, the polishing composition of Comparative Example 6 does not contain a stabilizer, which is an essential component of the polishing composition of the present invention. Therefore, although bubbles are generated immediately after the polishing composition is prepared, making it difficult to handle in practical terms, the aforementioned performance evaluation was performed on the polishing composition after preparation. Note that the polishing test itself was conducted after bubble generation ceased.

[0074] As shown in the results of Table 4, the polishing rate in the polishing composition of Comparative Example 6 was less than half that of Examples 12 and 13, and scratches were observed on the substrate surface. In contrast, Examples 12 and 13, which met the requirements of the polishing composition of the present invention, had high polishing rates and no scratches were observed on the substrate surface.

[0075] As shown in the results of Table 4, the polishing composition of Comparative Example 7 does not contain the oxidation accelerator, which is an essential component of the polishing composition of the present invention. Compared with the polishing compositions of Examples 12 and 13 corresponding to Comparative Example 7, the polishing rate is low, and scratches are observed on the substrate surface. In contrast, Examples 12 and 13, which meet the requirements of the polishing composition of the present invention, have high polishing rates, and no scratches are observed on the substrate surface.

[0076] (3) Polishing of GaP substrate The polishing conditions for the polishing test of the polishing object using the polishing compositions prepared as Examples 14 and 15 and Comparative Examples 8 and 9 are as follows. The results of the polishing test conducted under these polishing conditions are shown in Table 5 below.

[0077] (GaP substrate polishing conditions Grinding device: Single-sided grinding machine platform diameter 360mm Polishing object: 2-inch GaP substrate Abrasive pad: Non-woven SUBA800 without groove Grinding pressure: 200g / cm 2 Platform speed: 60rpm Grinding time: 20min Abrasive composition supply: circulation, flow rate 200ml / min (Polishing speed ratio of GaP substrate) The weight of a 2-inch GaP substrate (hereinafter referred to as the "GaP substrate") being polished was measured before and after the polishing test, and the polishing rate was calculated from the weight difference. The polishing rate ratio is expressed as a relative value, with the value of Comparative Example 8 set to 1 (baseline). A larger polishing rate ratio indicates a higher polishing rate and higher productivity.

[0078] (Substrate surface condition of GaP substrate and substrate surface roughness (Sa) of GaP substrate) The substrate surface condition and substrate surface roughness (Sa) were measured using the same method as for the GaAs substrate and the InP substrate.

[0079] [Table 5]

[0080] (Investigation on GaP substrates) As shown in Table 5, the polishing composition of Comparative Example 8 does not contain a stabilizer, which is an essential component of the polishing composition of the present invention. Therefore, although bubbles are generated immediately after the polishing composition is prepared, making it difficult to handle in practical terms, the aforementioned performance evaluation was performed on the polishing composition after preparation. Note that the polishing test itself was performed after bubble generation ceased.

[0081] As shown in the results of Table 5, the polishing rate of the polishing composition of Comparative Example 8 is lower than that of Examples 14 and 15, and the surface roughness (Sa) is higher than that of Examples 14 and 15. In contrast, Examples 14 and 15, which meet the requirements of the polishing composition of the present invention, have high polishing rates and low surface roughness.

[0082] As shown in the results of Table 5, the polishing composition of Comparative Example 9 does not contain the oxidation accelerator, which is an essential component of the polishing composition of the present invention. Compared to the polishing compositions of Examples 14 and 15 corresponding to Comparative Example 9, the polishing rate is low, the surface roughness is high, and scratches are observed on the substrate surface. In contrast, Examples 14 and 15, which meet the requirements of the polishing composition of the present invention, have high polishing rates, low surface roughness, and no scratches are observed.

[0083] (4) Polishing of GaN substrate The polishing conditions for the polishing test of the polishing object using the polishing compositions prepared as Examples 16 and 17 and Comparative Examples 10 and 11 are as follows. The results of the polishing test conducted under these polishing conditions are shown in Table 6 below.

[0084] (GaN substrate polishing conditions) Grinding device: Single-sided grinding machine platform diameter 360mm Polishing object: 2-inch GaN substrate Abrasive pad: Non-woven SUBA800 without groove Grinding pressure: 500g / cm 2 Platform speed: 60rpm Grinding time: 120min Abrasive composition supply: circulation, flow rate 200ml / min (GaN substrate polishing speed ratio) The weight of a 2-inch GaN substrate (hereinafter referred to as the "GaN substrate") being polished was measured before and after the polishing test, and the polishing rate was calculated from the weight difference. The polishing rate ratio is expressed as a relative value, with the value of Comparative Example 10 set to 1 (baseline). A larger polishing rate ratio indicates a faster polishing rate and higher productivity.

[0085] (Substrate Surface Condition of GaN Substrate and Substrate Surface Roughness (Sa) of GaN Substrate) The substrate surface conditions and substrate surface roughness (Sa) were measured using the same methods as those for the GaAs substrate, InP substrate, and GaP substrate.

[0086] [Table 6]

[0087] (Investigation of GaN substrates) As shown in Table 6, the polishing composition of Comparative Example 10 does not contain a stabilizer, which is an essential component of the polishing composition of the present invention. Therefore, although bubbles are generated immediately after the polishing composition is prepared, making it difficult to handle in practical terms, the aforementioned performance evaluation was performed on the polishing composition after preparation. Note that the polishing test itself was performed after bubble generation ceased.

[0088] As shown in the results of Table 6, the polishing rate of the polishing composition of Comparative Example 10 is lower than those of Examples 16 and 17, and the surface roughness (Sa) is higher than those of Examples 16 and 17. In contrast, Examples 16 and 17, which meet the requirements of the polishing composition of the present invention, have high polishing rates and low surface roughness.

[0089] As shown in the results of Table 6, the polishing composition of Comparative Example 11 is an example in which the oxidation accelerator, which is an essential component of the polishing composition of the present invention, is not contained. Compared with the polishing compositions of Examples 16 and 17 corresponding to Comparative Example 11, the polishing rate is low and the surface roughness is high. In contrast, Examples 16 and 17, which meet the requirements of the polishing composition of the present invention, have high polishing rates and low surface roughness.

[0090] As described above, by using the polishing composition of the present invention and performing the polishing method using the polishing composition of the present invention, the storage stability of the polishing composition can be improved, and the polishing process of the polishing object can be performed stably for a long time. As a result, the polishing rate of semiconductor wafers such as GaAs wafers, InP wafers, GaP wafers, and GaN wafers can be improved, and the surface roughness of the substrate after polishing can be improved, and a semiconductor wafer with a glossy substrate surface can be produced.

[0091] Industrial applicability The polishing composition and polishing method using the polishing composition of the present invention can be used for primary or secondary polishing of electronic components used in various electronic devices such as semiconductor devices and components. In particular, it is suitable for polishing compound semiconductor wafers containing III-V compounds as constituent components, such as GaAs wafers, InP wafers, GaP wafers, and GaN wafers.

Claims

1. An abrasive composition for polishing an object containing a Group III-V compound as a constituent component. The abrasive composition comprises colloidal silica, an oxidizing agent, an oxidation accelerator, a stabilizer and water. The oxidation promoter is used to promote the oxidation reaction of the oxidant on the surface of the polishing object; The stabilizer is used to control the promoting effect of the oxidation promoter on the oxidation reaction of the surface of the polishing object. The pH of the polishing composition at 25° C. is in the range of 0.1 to 6.

0. The oxidation promoter is any one of an inorganic acid metal salt or an organic acid metal salt, The stabilizer is a polycarboxylic acid, The polycarboxylic acid is malonic acid.

2. The polishing compound according to claim 1, wherein The III-V group compound is at least one selected from gallium arsenide, gallium phosphide and indium phosphide.

3. The polishing compound according to claim 1, wherein The oxidizing agent is peroxide, permanganic acid or its salt, chromic acid or its salt, peroxy acid or its salt, halogen oxygen-containing acid or its salt, and a mixture thereof.

4. The polishing compound according to claim 1, wherein The oxidant is hydrogen peroxide.

5. The polishing compound according to claim 1, wherein The inorganic acid metal salt is any one of ferric nitrate and ferric sulfate.

6. The polishing compound according to claim 1, wherein The pH of the polishing composition at 25° C. is in the range of 0.5 to 5.

0.

7. A polishing method using an abrasive composition, characterized in that: An object to be polished containing a Group III-V compound as a constituent is polished using the polishing composition according to any one of claims 1 to 6.

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