Abrasive composition and polishing method using the abrasive composition

Abstract

The present invention provides an abrasive composition which can achieve the acceleration of mirror polishing processing such as polishing speed, and improve the smoothness and flatness of the wafer surface of a semiconductor wafer after mirror polishing, enabling high-precision mirror finishing, and having excellent storage stability. The abrasive composition is a composition for polishing a polishing object containing a III-V compound as a constituent component, and includes colloidal silica, an oxidizing agent, an oxidation accelerator for promoting the surface oxidation reaction of the polishing object by the oxidizing agent; a stabilizer for controlling the promotion of the surface oxidation reaction of the polishing object by the oxidation accelerator; and water.

Description

Technical Field

[0001] The present invention relates to an abrasive composition and an abrasive method using the abrasive composition. More specifically, the present invention relates to an abrasive composition for mirror-polishing the wafer surface of a compound semiconductor wafer containing III-V compounds such as gallium arsenide (GaAs), indium phosphide (InP), gallium phosphide (GaP), and gallium nitride (GaN) as constituent components, and an abrasive method using the abrasive composition. Background Art

[0002] Conventionally, as substrates or elements of various semiconductor devices such as semiconductor lasers, light-emitting diodes, optical modulation elements, optical detection elements, and solar cells, compound semiconductor wafers (hereinafter, simply referred to as "semiconductor wafers") containing III-V compounds such as GaAs, InP, GaP, and GaN as constituent components have been mostly used. In particular, in recent years, due to the popularization of various electronic devices, etc., the demand for them has increased significantly.

[0003] A semiconductor wafer is usually obtained by thinning a single crystal grown by crystal growth of an III-V compound, performing lapping, and then performing various processing steps such as etching and polishing, and finally performing final polishing to complete the finishing process.

[0004] Final polishing, which is the final process (finishing process) equivalent to a semiconductor wafer, is a process for smoothing the wafer surface of the semiconductor wafer and finishing it into a mirror surface. For example, a polishing pad is mounted on a rotatable circular table, and while dropping a previously prepared polishing liquid onto the pad surface (polishing surface) of the polishing pad, the semiconductor wafer before polishing is pressed against the pad surface while the polishing pad is rotated, thereby polishing the wafer surface by chemical action and mechanical action.

[0005] Conventionally, the polishing of the above-mentioned semiconductor wafers has been performed in two stages: primary polishing (rough polishing) and secondary polishing (mirror finishing polishing). For example, it is known that in the primary polishing of a semiconductor wafer, a polishing method in which polishing using abrasive grains having a large particle size is first performed and then polishing using abrasive grains having a small particle size is performed (see Patent Document 1); a polishing method using an abrasive having a characteristic particle shape and particle size distribution of abrasive grains, particularly using sodium dichloroisocyanurate as an oxidizing agent (see Patent Document 2); or a polishing method in which polishing liquids having different compositions are used in the front-stage polishing and the rear-stage polishing in the primary polishing of a GaAs wafer (see Patent Document 3), etc. Thus, various methods have been adopted for mirror-finishing the wafer surface of a semiconductor wafer with high precision.

[0006] In particular, after processing a semiconductor wafer by mirror polishing, a layer is further formed on the mirror surface by epitaxial growth. Therefore, the processing accuracy (finishing accuracy) of mirror polishing based on final polishing is very important, and it is required to form a wafer surface with few irregularities, excellent smoothness and flatness, small undulations, and few surface abnormalities such as depressions.

[0007] Prior art documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 2002-18705

[0010] Patent Document 2: Japanese Patent Application Laid-Open No. 2005-264057

[0011] Patent Document 3: Japanese Patent Application Laid-Open No. 2008-198724 Summary of the invention

[0012] Problems to be solved by the invention

[0013] However, in the polishing methods or polishing liquids (polishing agent compositions) used in the above Patent Documents 1 to 3, etc., sometimes the polishing process is difficult to be speeded up, such as a long processing time, or the processing accuracy required for mirror polishing cannot be fully satisfied. In addition, the techniques disclosed in Patent Document 2 and Patent Document 3 using sodium dichloroisocyanurate as an oxidizing agent have a great impact on the storage stability of the polishing liquid itself, and there is a problem that the polishing speed is likely to decrease over time and it is difficult to use for a long time.

[0014] Therefore, in view of the above actual situation, the subject of the present invention is to provide a polishing agent composition with excellent storage stability, which can achieve the speed-up of mirror polishing processing such as polishing speed, and improve the smoothness and flatness of the wafer surface of the semiconductor wafer after mirror polishing, and to provide a polishing method using this polishing agent composition.

[0015] Means for solving the problems

[0016] The inventors of the present application have conducted in-depth research to solve the above problems, and as a result, it has been found that by performing polishing using a polishing agent composition prepared by containing specific components, the speed-up of mirror polishing processing of semiconductor wafers can be achieved, and thus the present invention shown below has been completed.

[0017] [1] An abrasive composition, which is an abrasive composition for polishing an object to be polished containing a group III-V compound as a constituent, comprising colloidal silica; an oxidizing agent; an oxidation promoter for promoting the oxidation reaction of the surface of the object to be polished by the oxidizing agent; a stabilizer for controlling the promoting effect of the oxidation reaction of the surface of the object to be polished by the oxidation promoter; and water.

[0018] [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 compound, indium-gallium-phosphorus compound, aluminum-gallium-arsenic compound, indium-aluminum-gallium-arsenic compound, gallium nitride, gallium-antimony compound, and indium-antimony compound.

[0019] [3] The abrasive composition according to [1] or [2] above, wherein the oxidizing agent is a peroxide, permanganic acid or its salt, chromic acid or its salt, peroxy acid or its salt, halogen oxyacid or its salt, oxyacid or its salt, and mixtures thereof.

[0020] [4] The abrasive composition according to any one of [1] to [3] above, wherein the oxidizing agent is hydrogen peroxide.

[0021] [5] The abrasive composition according to any one of [1] to [4] above, wherein the oxidation promoter is either an inorganic acid metal salt or an organic acid metal salt.

[0022] [6] The abrasive composition according to [5] above, wherein the inorganic acid metal salt is either ferric nitrate or ferric sulfate.

[0023] [7] The abrasive composition 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 polyamino carboxylic acid.

[0024] [8] The abrasive composition according to [7] above, wherein the polycarboxylic acid is either malonic acid or citric acid.

[0025] [9] The abrasive composition according to any one of [1] to [8] above, wherein the pH (25 °C) is in the range of 0.1 to 6.0.

[0026]

[10] An abrasive method using an abrasive composition, which uses the abrasive composition according to any one of [1] to [9] above to polish an object to be polished containing a group III-V compound as a constituent.

[0027] Advantages of the Invention

[0028] The abrasive composition according to the present invention is characterized by containing an oxidizing agent, an oxidation promoter, and a stabilizer. By using this abrasive composition to polish a semiconductor wafer, a mirror polishing process with excellent flatness and smoothness can be performed at a high polishing rate. Furthermore, the effect of excellent long-term storage stability of the abrasive composition can also be exhibited. Detailed Embodiments

[0029] Hereinafter, embodiments of the present invention will be described. The present invention is not limited to the following embodiments, and can be changed, modified, and improved without departing from the scope of the invention.

[0030] 1. Abrasive Composition

[0031] The abrasive composition according to an embodiment of the present invention contains colloidal silica, an oxidizing agent, an oxidation promoter, a stabilizer, and water, and these raw materials are formulated at a specific mixing ratio. It should be noted that although the abrasive composition of this embodiment has excellent storage stability, after being prepared into an abrasive composition, it is preferably quickly used for polishing semiconductor wafers such as GaAs wafers, InP wafers, GaP wafers, and GaN wafers. For example, it is preferably used for polishing within 48 hours from the preparation of the abrasive composition, and more preferably within 24 hours from the preparation.

[0032] 1.1 Colloidal Silica

[0033] The average particle size (D50) of the colloidal silica used as a raw material of the abrasive composition of this embodiment is preferably in the range of 10 to 200 nm, and more preferably the average particle size (D50) is 20 to 100 nm. When 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 becomes large, and polishing may not proceed smoothly. If the average particle size (D50) of the colloidal silica exceeds 200 nm, scratches may be generated on the substrate. Here, the average particle size (D50) of the colloidal silica is analyzed and calculated based on the observation results of a transmission electron microscope (TEM) (detailed content will be described later).

[0034] The shape of the colloidal silica is known to be spherical, sugarloaf-shaped (granular with convex portions on the surface), irregular-shaped, etc., and the primary particles are monodispersed in water to form a colloid. Various shapes of colloidal silica can be used as the raw material of the abrasive composition of this embodiment.

[0035] The colloidal silica used as a material can be produced by conventionally known production methods. For example, the following methods are known: the water glass method in which an alkali metal silicate such as sodium silicate or potassium silicate is used as a raw material and the raw material is subjected to a condensation reaction in an aqueous solution to grow the particles of colloidal silica; the alkoxysilane method in which a tetraalkoxysilane such as tetraethoxysilane is used as a raw material and the raw material is subjected to a condensation reaction by hydrolysis using an acid or a base in a solvent containing a water-soluble organic solvent such as an alcohol to grow the particles of colloidal silica; or a method in which metallic silicon and water are reacted in the presence of an alkali catalyst to synthesize colloidal silica. It should be noted that, in terms of production cost, the water glass method can be preferably used. These synthesis methods can be appropriately used to produce the colloidal silica which is a material used in the abrasive composition of the present embodiment.

[0036] In the abrasive composition of the present embodiment, the content (content ratio) of the colloidal silica contained in the abrasive composition is preferably in the range of 1 to 50% by mass, more preferably 2 to 40% by mass. When the content of the colloidal silica is less than 1% by mass, the grinding resistance between the substrate and the grinding pad during grinding becomes large, and grinding may not proceed smoothly. If the content of the colloidal silica exceeds 50% by mass, the colloidal silica may easily gel.

[0037] 1.2 Oxidizing agent

[0038] As the oxidizing agent used as a material for the abrasive composition of the present embodiment, peroxides, permanganic acid or its salts, chromic acid or its salts, peroxyacids or their salts, halogen oxyacids or their salts, oxyacids or their salts, and mixtures of two or more of them can be used.

[0039] 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, peroxophosphoric acid, sodium perborate, performic acid, peracetic acid, hypochlorous acid, sodium hypochlorite, calcium hypochlorite, etc. In particular, hydrogen peroxide, persulfuric acid and its salts, and hypochlorous acid and its salts are preferably used, and hydrogen peroxide is more preferably used.

[0040] The oxidizing agent has the function of oxidizing the surface of a semiconductor wafer such as a GaAs wafer to form an oxide layer, and has the effect of facilitating the grinding of the semiconductor wafer which is the object to be ground. Further, it has the effect of oxidizing grinding debris such as arsenic compounds generated and discharged during the grinding of the semiconductor wafer, and also has the function of suppressing the deterioration of the working environment.

[0041] In the abrasive composition of the present embodiment, the content (content rate) of the oxidizing agent contained in the abrasive composition is preferably in the range of 0.01 to 10.0% by mass, more preferably 0.1 to 5.0% by mass. When the content of the oxidizing agent is less than 0.01% by mass, the polishing rate may decrease. If the content of the oxidizing agent exceeds 10.0% by mass, the surface roughness of the polished substrate may deteriorate.

[0042] 1.3 Oxidation promoter

[0043] As the oxidation promoter used as the material for the abrasive composition of the present embodiment, an inorganic acid metal salt or an organic acid metal salt can be used. In particular, an inorganic acid metal salt is preferably used.

[0044] If the inorganic acid metal salt is further specifically represented, iron salts, copper salts, silver salts, manganese salts, etc. of nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, etc. can be used. For example, iron(III) nitrate, iron(III) sulfate, iron(II) sulfate, iron(III) chloride or iron(II) chloride is preferably used, and iron(III) nitrate is particularly more preferably used. It should be noted that any of anhydrous substances or hydrates of these inorganic acid metal salts can be used.

[0045] In addition, as the organic acid metal salt, metal salts of polycarboxylic acids, metal salts of polyaminocarboxylic acids, etc. can be cited. If more specifically represented, as the metal salt of polycarboxylic acid, metal salts of oxalic acid, malonic acid, succinic acid, maleic acid, phthalic acid, citric acid, etc. can be cited, and as the metal salt of polyaminocarboxylic acid, metal salts of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminediacetic acid, triethylenetetraminehexaacetic acid, etc. can be cited. Metal salts of these organic acids such as iron salts, copper salts, silver salts, and manganese salts can be used.

[0046] The oxidation promoter has the effect of promoting the oxidation reaction of the semiconductor wafer caused by the above-mentioned oxidizing agent. Therefore, the effect of making the polishing of the semiconductor wafer easier is achieved.

[0047] In the abrasive composition of the present embodiment, the content (content rate) of the oxidation promoter contained in the abrasive composition is preferably in the range of 0.01 to 10.0% by mass, more preferably 0.02 to 5.0% by mass. When the content of the oxidation promoter is less than 0.01% by mass, the polishing rate becomes low and the surface roughness of the polished substrate may deteriorate. Even if the content of the oxidation promoter exceeds 10.0% by mass, the effect of the oxidation promoter reaches its peak and it is economically disadvantageous.

[0048] 1.4 Stabilizer

[0049] As the stabilizer used as a material for the abrasive composition of the present embodiment, at least one or more selected from phosphoric acid, phosphorous acid, organic phosphonic acid, polycarboxylic acid, or polyamino carboxylic acid can be used. Specific examples of the polycarboxylic acid include oxalic acid, malonic acid, succinic acid, maleic acid, phthalic acid, and citric acid. Further, specific examples of the polyamino carboxylic acid include ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminediacetic acid, triethylenetetraminehexaacetic acid, etc. In addition, their alkali metal salts can also be used.

[0050] 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, α-methylphosphonosuccinic acid, etc.

[0051] 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 particularly more preferably used.

[0052] The stabilizer has the function of controlling the promoting effect of the oxidation reaction of the semiconductor wafer by the oxidation promoter. Thereby, the progress of the oxidation reaction using the oxidizing agent and the oxidation promoter can be controlled. Therefore, after preparing the abrasive composition, the oxidation reaction on the surface of the object to be polished can be made to proceed slowly. As a result, the effect of the abrasive composition can be exerted for a long time, and the storage stability of the abrasive composition can be maintained. Thereby, the effect of enabling the polishing of the semiconductor wafer to proceed stably and smoothly for a long time is exerted.

[0053] In the abrasive composition of the present embodiment, the content (content rate) of the stabilizer contained in the abrasive composition is preferably in the range of 0.01 to 10.0% by mass, and more preferably 0.02 to 5.0% by mass. When the content of the stabilizer is less than 0.01% by mass, bubbles may be generated when preparing the abrasive composition, and the stability of the abrasive composition over time deteriorates. Even when the content of the stabilizer exceeds 10.0% by mass, the effect of the stabilizer reaches its peak, which is economically disadvantageous.

[0054] 1.5 Water

[0055] The water used as a material for the abrasive composition of the present embodiment is not particularly limited as long as it is water from which ions and floating substances have been removed, such as pure water, ultrapure water, or distilled water.

[0056] 1.6 Physical properties of the abrasive composition

[0057] In the abrasive composition of the present embodiment, the value of pH (25°C) is preferably in the range of 0.1 to 6.0, more preferably in the range of 0.5 to 5.0. It should be noted that the pH value of the abrasive composition can be adjusted according to the content ratios of the oxidation promoter and the stabilizer. Further, in order to adjust this pH value, an acidic compound or a basic compound may be appropriately added. When the value of pH (25°C) of the abrasive composition is less than 0.1, corrosion of the polishing machine and peripheral devices may easily occur. If the value of pH (25°C) of the abrasive composition exceeds 6.0, gelation of colloidal silica is likely to occur, and the surface roughness of the polished substrate may deteriorate.

[0058] 2. Object to be polished

[0059] The semiconductor wafer as the object to be polished polished with the abrasive composition of the present embodiment contains a III-V compound as a constituent component, and is thinned from the already described gallium arsenide (GaAs) and indium phosphide (InP). Further, as the III-V compound, it is a substance selected from gallium phosphide (GaP), indium arsenide (InAs), aluminum arsenide (AlAs), indium-gallium-arsenide compound (InGaAs), indium-gallium-arsenide-phosphorus compound (InGaAsP), aluminum-gallium-arsenide compound (AlGaAs), indium-aluminum-gallium-arsenide compound (InAlGaAs), gallium nitride (GaN), gallium-antimony compound (GaSb), and indium-antimony compound (InSb). A semiconductor wafer (III-V compound semiconductor wafer) that forms the object to be polished contains at least one or more of these III-V compounds as constituent components.

[0060] 3. Polishing method using the abrasive composition

[0061] Using the abrasive composition of the present embodiment, a semiconductor wafer containing a III-V compound as a constituent component is polished as the object to be polished, and a polishing method using the abrasive composition of an embodiment of the present invention (hereinafter, simply referred to as "polishing method") is implemented. Here, the polishing method is composed of two stages (processes) of primary polishing and secondary polishing performed after the primary polishing, and both have the properties of chemical polishing and mechanical polishing.

[0062] The primary polishing in the polishing method aims to accelerate the polishing speed during polishing, in other words, to improve the efficiency of polishing, and to ensure the flatness of the semiconductor wafer. Therefore, the mechanical polishing factor is relatively high. On the other hand, the secondary polishing in the polishing method mainly aims at the final finishing of the wafer surface of the semiconductor wafer into a mirror surface, removing scratches, haze, processing strain, etc. on the wafer surface, and finishing it into a perfect mirror surface. Therefore, the chemical polishing factor is relatively high.

[0063] Here, during the secondary polishing, for the purpose of finishing into a perfect mirror surface, for example, a two-layer structure in which a base layer containing polyester fibers is provided on the polishing pad and a polyurethane foam surface layer is provided on the base layer is often used. In addition, after the above secondary polishing, in order to remove the attachments remaining on the wafer surface of the semiconductor wafer and to remove the oxide film on the wafer surface, an etching process can also be performed, and a film formation process of forming a film on the wafer surface by epitaxial growth can be performed. Here, the abrasive composition of the present embodiment can be used when applying the polishing method of the present embodiment to the semiconductor wafer, and can be adopted at any stage (process) of the above primary polishing and secondary polishing.

[0064] It should be noted that in the above, as the polishing pad, an example of a polishing pad having a two-layer structure including a base layer containing polyester fibers and a polyurethane foam surface layer used during secondary polishing is illustrated, but it is not limited thereto, and a conventionally known polishing pad including non-woven fabric, foamed polyurethane, porous resin, and non-porous resin can be appropriately selected and used. In addition, in order to promote the supply of the abrasive composition to the polishing pad or to retain a certain amount of the abrasive composition on the polishing pad, groove processing such as a lattice shape, a concentric circle shape, or a spiral shape can be performed on the surface of the polishing pad.

[0065] [Examples]

[0066] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. In addition, in the present invention, in addition to the following examples, various changes and improvements can be made based on the knowledge of those skilled in the art without departing from the gist of the present invention.

[0067] (Preparation of Abrasive Composition)

[0068] Using the materials listed in Table 1 below, abrasive compositions of Examples 1 to 17 and Comparative Examples 1 to 11 were formulated by mixing them in such a way that the contents (mass %) listed in Table 1 were included. It should be noted that the abrasive compositions of Examples 1, 12, 14, and 16 are the same, the abrasive compositions of Examples 4, 13, 15, and 17 are the same, the abrasive compositions of Comparative Examples 1, 6, 8, and 10 are the same, and the abrasive compositions of Comparative Examples 4, 7, 9, and 11 are the same. Here, the abrasive compositions of Examples 1 to 10, 12 to 17 and Comparative Examples 4, 7, 9, and 11 were immediately subjected to a polishing test after being prepared as abrasive compositions. On the other hand, the abrasive compositions of Comparative Examples 1 to 3, 6, 8, and 10 generated bubbles after being prepared as abrasive compositions, so they were subjected to a polishing test after waiting for the generation of the bubbles to end. Furthermore, the abrasive composition of Example 11 was subjected to a polishing test 2 hours after being prepared as an abrasive composition, and the abrasive composition of Comparative Example 5 generated bubbles after being prepared as an abrasive composition, so it was subjected to a polishing test 2 hours after the generation of the bubbles ended.

[0069] It should be noted that the content of the stabilizer in the abrasive composition was prepared in such a way that it was constant in mol%, so the values in the mass % representations in Tables 1 to 6 reflect the respective molecular weight sizes. In addition, "HEDP" in Tables 1 and 2 represents 1-hydroxyethylidene-1,1-diphosphonic acid, EDTA represents ethylenediaminetetraacetic acid, and EDTA iron represents ferric ethylenediaminetetraacetate.

[0070] [Table 1]

[0071]

[0072] (Particle size of colloidal silica)

[0073] The particle size (Heywood diameter) of colloidal silica was measured as the Heywood diameter (projected area equivalent circle diameter) by taking a photograph of a field of view at a magnification of 100,000 times using a transmission electron microscope (TEM) (manufactured by JEOL Ltd., transmission electron microscope JEM2000FX (200 kV)) and analyzing the photograph using analysis software (manufactured by Mountech Co., Ltd., Mac-View Ver. 4.0). The average particle size of colloidal silica was calculated by analyzing about 2000 colloidal silica particle sizes using the above method and using the above analysis software (manufactured by Mountech Co., Ltd., Mac-View Ver. 4.0) to calculate the average particle size (D50) of the particle size at which the cumulative particle size distribution (cumulative volume basis) from the small particle size side was 50%.

[0074] (1) Polishing of GaAs substrate

[0075] The polishing conditions for the polishing test of the objects to be polished using the abrasive compositions prepared in Examples 1 to 11 and Comparative Examples 1 to 5 are as described below. The results of the polishing tests conducted under these polishing conditions are shown in Tables 2 and 3 below.

[0076] (Polishing Conditions for GaAs Substrate)

[0077] Polishing apparatus: Single-sided polishing machine, platen diameter 350 mm

[0078] Object to be polished: 3-inch GaAs substrate

[0079] Polishing pad: Hard polyurethane IC1400 with grooves

[0080] Polishing pressure: 200 g / cm 2

[0081] Platen rotation speed: 60 rpm

[0082] Polishing time: 10 min

[0083] Supply amount of abrasive composition: 1-way supply, flow rate 40 ml / min

[0084] (Polishing Speed Ratio of GaAs Substrate)

[0085] The weight of the 3-inch GaAs substrate (hereinafter simply referred to as "GaAs substrate") of the object to be polished before and after the polishing test is measured, and the polishing speed is calculated from the weight difference. In addition, the polishing speed ratio is expressed as a relative value when the value of the polishing speed of Comparative Example 1 is set to 1 (reference). The larger the value of the polishing speed ratio, the higher the polishing speed and the higher the productivity.

[0086] (Surface State of the GaAs Substrate)

[0087] The surface of the GaAs substrate after the polishing test is observed visually and with a scanning white light interferometer (VS-1540 manufactured by Hitachi High-Tech Science Corporation).

[0088] (Surface Roughness (Sa) of the GaAs Substrate)

[0089] Using the above scanning white light interferometer, the surface roughness (Sa) of the surface of the GaAs substrate after the polishing test is measured with a measurement range of 102 μm × 102 μm.

[0090] [Table 2]

[0091]

[0092] (Consideration on GaAs Substrate)

[0093] As shown in Table 2, the abrasive composition of Comparative Example 1 does not contain a stabilizer which is an essential component of the abrasive composition of the present invention. Therefore, a large amount of bubbles are generated immediately after the preparation of the abrasive composition. Although it is difficult to handle in practice, the above performance evaluation was carried out on the prepared abrasive composition. It should be noted that the grinding test itself was carried out after the generation of bubbles stopped.

[0094] As shown in the results of Table 2 above, it was confirmed that the value of the grinding rate in the abrasive composition of Comparative Example 1 was less than half of the values of the grinding rates of the abrasive compositions of Examples 1 to 4, and the value of the substrate surface roughness (Sa) deteriorated significantly with respect to the abrasive compositions of Examples 1 to 4. Furthermore, although gloss was confirmed in the central part of the substrate surface, cloudiness occurred in the peripheral part of the substrate. In addition, a plurality of visible scratches were also observed.

[0095] As shown in Table 2, the abrasive composition of Comparative Example 2 used nitric acid instead of the stabilizer used in the abrasive compositions of Examples 1 to 4 of the abrasive composition of the present invention. Therefore, a large amount of bubbles are generated immediately after the preparation of the abrasive composition. Although it is difficult to handle in practice, the above performance evaluation was carried out on the prepared abrasive composition. It should be noted that the grinding test itself was carried out after the generation of bubbles stopped.

[0096] As shown in the results of Table 2 above, it was confirmed that the value of the grinding rate in the abrasive composition of Comparative Example 2 was lower than that of the abrasive compositions of Examples 1 to 4. On the other hand, both the substrate surface roughness and the state of the substrate surface were good. It should be noted that, as described above, a large amount of bubbles were generated immediately after the preparation. Therefore, the storage stability of the abrasive composition was evaluated as follows. The results are shown in Table 3 below.

[0097] [Table 3]

[0098]

[0099] As shown in the results of Table 3 above, Comparative Example 5 is the result of subjecting the abrasive composition prepared in Comparative Example 2 to a grinding test 2 hours after the generation of bubbles stopped after the preparation. Compared with Comparative Example 2 in which grinding was carried out immediately after the generation of bubbles stopped after the preparation, it was confirmed that the grinding rate decreased to half. That is, it indicates a lack of storage stability. On the other hand, Example 11 is the result of subjecting the abrasive composition prepared in Example 4 to a grinding test 2 hours after the preparation. It can be understood that the grinding performance shows almost the same result as the abrasive composition of Example 4, and the storage stability is excellent.

[0100] As shown in the results of Table 2 above, the abrasive composition of Comparative Example 3 is an example in which acetic acid is used instead of the stabilizer used in the abrasive compositions of Examples 1 to 4 of the abrasive composition of the present application. It is shown that although gloss is confirmed on the substrate surface after the polishing test, multiple scratches are confirmed visually, and the surface roughness value also deteriorates significantly. In contrast, in the case of Examples 1 to 4 that satisfy the conditions of the abrasive composition of the present invention, gloss is confirmed on the substrate surface after the polishing test, no scratches are confirmed visually, and the surface roughness value is also significantly improved compared to Comparative Example 3.

[0101] As shown in the results of Table 2 above, the abrasive composition of Comparative Example 4 is an example in which the oxidation promoter, which is an essential component, is not contained in the abrasive composition of the present invention. It was confirmed that for the abrasive compositions of Examples 4 to 7 corresponding to this Comparative Example 4, the polishing rate was low, cloudiness was confirmed on the substrate surface after the polishing test, and the surface roughness results were significantly reduced. In contrast, in the case of Examples 4 to 7 that satisfy the requirements of the abrasive composition of the present invention, an increase in the polishing rate was confirmed, showing that gloss was confirmed on the substrate surface after the polishing test and the surface roughness results were good.

[0102] It should be noted that for the composition of the abrasive composition of Example 8 compared to that of Example 4, the content (concentration) of colloidal silica was increased, for the composition of the abrasive composition of Example 9 compared to that of Example 4, the content (concentration) of hydrogen peroxide as an oxidizing agent was increased, and for the composition of the abrasive composition of Example 10 compared to that of Example 4, the content (concentration) of the oxidation promoter was increased. The abrasive compositions of these Examples 8 to 10 all showed good polishing performance.

[0103] (2) Polishing of InP Substrate

[0104] The polishing conditions for the polishing test of the polishing object using the abrasive compositions prepared as Examples 12 and 13 and Comparative Examples 6 and 7 are as described below. The results of the polishing test conducted under these polishing conditions are shown in Table 4 below.

[0105] (Polishing Conditions for InP Substrate)

[0106] Polishing apparatus: Single-sided polishing machine, table diameter 360 mm

[0107] Polishing object: 2-inch InP substrate

[0108] Polishing pad: Non-woven fabric SUBA800 without grooves

[0109] Polishing pressure: 200 g / cm 2

[0110] Platform rotation speed: 60 rpm

[0111] Grinding time: 20 min

[0112] Supply amount of abrasive composition: Circulation, flow rate 200 ml / min

[0113] (Grinding speed ratio of InP substrate)

[0114] Measure the weight of a 2-inch InP substrate (hereinafter simply referred to as "InP substrate") to be ground before and after the grinding test is carried out, and calculate the grinding speed from the weight difference. In addition, the grinding speed ratio is expressed as a relative value when the value of Comparative Example 6 is set to 1 (reference). The larger the value of the grinding speed ratio, the higher the grinding speed and the higher the productivity.

[0115] (State of the substrate surface of the InP substrate and surface roughness (Sa) of the InP substrate)

[0116] Measure the state of the substrate surface and the surface roughness (Sa) of the substrate by the same method as for the GaAs substrate.

[0117] [Table 4]

[0118]

[0119] (Consideration regarding InP substrate)

[0120] As shown in Table 4, the abrasive composition of Comparative Example 6 does not contain a stabilizer which is an essential component of the abrasive composition of the present invention. Therefore, although bubbles are generated immediately after the preparation of the abrasive composition and it is difficult to handle in practice, the above performance evaluation is carried out on the prepared abrasive composition. It should be noted that the grinding test itself is carried out after the generation of bubbles has stopped.

[0121] As shown in the results of Table 4 above, the value of the grinding speed in the abrasive composition of Comparative Example 6 is less than half of those of Examples 12 and 13, and scratches are observed on the substrate surface. In contrast, the grinding speeds of Examples 12 and 13 that satisfy the conditions of the abrasive composition of the present invention are high and no scratches are observed on the substrate surface.

[0122] As shown in the results of Table 4 above, the abrasive composition of Comparative Example 7 is an example in which the abrasive composition of the present invention does not contain an oxidation promoter as an essential component. The grinding speed is low compared to the abrasive compositions of Examples 12 and 13 corresponding to this Comparative Example 7, and scratches are observed on the substrate surface. In contrast, the grinding speeds of Examples 12 and 13 that satisfy the conditions of the abrasive composition of the present invention are high and no scratches are observed on the substrate surface.

[0123] (3) Grinding of GaP Substrate

[0124] The grinding conditions for the grinding test of the grinding object using the abrasive compositions prepared as in Examples 14 and 15 and Comparative Examples 8 and 9 are as follows. The results of the grinding test conducted under these grinding conditions are shown in Table 5 below.

[0125] (Grinding Conditions of GaP Substrate

[0126] Grinding apparatus: Single-sided grinder, table diameter 360 mm

[0127] Object to be ground: 2-inch GaP substrate

[0128] Grinding pad: Non-woven fabric SUBA800, without grooves

[0129] Grinding pressure: 200 g / cm 2

[0130] Table rotation speed: 60 rpm

[0131] Grinding time: 20 min

[0132] Supply amount of abrasive composition: Circulation, flow rate 200 ml / min

[0133] (Grinding Speed Ratio of GaP Substrate)

[0134] Measure the weights of the 2-inch GaP substrate (hereinafter simply referred to as "GaP substrate") of the object to be ground before and after the grinding test, and calculate the grinding speed from the weight difference. In addition, the grinding speed ratio is expressed as a relative value when the value of Comparative Example 8 is set to 1 (reference). The larger the value of the grinding speed ratio, the greater the grinding speed and the higher the productivity.

[0135] (State of the Substrate Surface of GaP Substrate and Substrate Surface Roughness (Sa) of GaP Substrate)

[0136] Measure the state of the substrate surface and the substrate surface roughness (Sa) using the same method as for GaAs substrates and InP substrates respectively.

[0137] [Table 5]

[0138]

[0139] (Consideration Regarding GaP Substrate)

[0140] As shown in Table 5, the abrasive composition of Comparative Example 8 does not contain a stabilizer which is an essential component of the abrasive composition of the present invention. Therefore, although bubbles are generated immediately after the preparation of the abrasive composition and it is difficult to handle in practice, the above performance evaluation is carried out on the prepared abrasive composition. It should be noted that the polishing test itself is carried out after the generation of bubbles has stopped.

[0141] As shown in the results of Table 5 above, the polishing rate of the abrasive 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 satisfy the conditions of the abrasive composition of the present invention have a high polishing rate and a low surface roughness.

[0142] As shown in the results of Table 5 above, the abrasive composition of Comparative Example 9 is an example in which the oxidation promoter which is an essential component is not contained in the abrasive composition of the present invention. Compared with the abrasive compositions of Examples 14 and 15 corresponding to this 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 satisfy the conditions of the abrasive composition of the present invention have a high polishing rate, a low surface roughness, and no scratches are observed.

[0143] (4) Polishing of GaN substrate

[0144] The polishing conditions for the polishing object using the abrasive compositions prepared as Examples 16 and 17 and Comparative Examples 10 and 11 are as described below. The results of the polishing test carried out under these polishing conditions are shown in Table 6 below.

[0145] (Polishing conditions for GaN substrate)

[0146] Polishing apparatus: Single-sided polishing machine, table diameter 360 mm

[0147] Polishing object: 2-inch GaN substrate

[0148] Polishing pad: Non-woven fabric SUBA800, no grooves

[0149] Polishing pressure: 500 g / cm 2

[0150] Table rotation speed: 60 rpm

[0151] Polishing time: 120 min

[0152] Supply amount of abrasive composition: Circulation, flow rate 200 ml / min

[0153] (Polishing rate ratio of GaN substrate)

[0154] The weight of a 2-inch GaN substrate (hereinafter simply referred to as "GaN substrate") to be polished before and after the implementation of the polishing test was measured, and the polishing rate was calculated from the weight difference. In addition, the polishing rate ratio is expressed as a relative value when the value of Comparative Example 10 is set to 1 (reference). The larger the value of the polishing rate ratio, the higher the polishing rate and the higher the productivity.

[0155] (State of the substrate surface of the GaN substrate and substrate surface roughness (Sa) of the GaN substrate)

[0156] The state of the substrate surface and the substrate surface roughness (Sa) were measured using the same method as for GaAs substrates, InP substrates, and GaP substrates, respectively.

[0157] [Table 6]

[0158]

[0159] (Consideration regarding the GaN substrate)

[0160] As shown in Table 6, the abrasive composition of Comparative Example 10 does not contain a stabilizer, which is an essential component of the abrasive composition of the present invention. Therefore, although bubbles are generated immediately after the preparation of the abrasive composition and it is difficult to handle in practical use, the above performance evaluation was carried out on the prepared abrasive composition. It should be noted that the polishing test itself was carried out after the generation of bubbles stopped.

[0161] As shown in the results of Table 6 above, the polishing rate of the abrasive composition of Comparative Example 10 is lower than that of Examples 16 and 17, and the surface roughness (Sa) is higher than that of Examples 16 and 17. In contrast, Examples 16 and 17 that satisfy the conditions of the abrasive composition of the present invention have a high polishing rate and a low surface roughness.

[0162] As shown in the results of Table 6 above, the abrasive composition of Comparative Example 11 is an example in which the abrasive composition of the present invention does not contain an oxidation promoter as an essential component. Compared with the abrasive compositions of Examples 16 and 17 corresponding to this Comparative Example 11, the polishing rate is low and the surface roughness is high. In contrast, Examples 16 and 17 that satisfy the conditions of the abrasive composition of the present invention have a high polishing rate and a low surface roughness.

[0163] As described above, by using the abrasive composition of the present invention and implementing the polishing method using the abrasive composition of the present invention, the storage stability of the abrasive composition can be made good, the polishing process of the polishing object can be stably performed for a long time, and furthermore, the polishing speed of semiconductor wafers such as GaAs wafers, InP wafers, GaP wafers, and GaN wafers can be increased, and a semiconductor wafer with improved surface roughness of the substrate after polishing and a good state of the shiny substrate surface can be produced.

[0164] Industrial applicability

[0165] The polishing agent composition of the present invention and the polishing method using the polishing agent composition can be used for primary polishing 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 group III-V compounds such as GaAs wafers, InP wafers, GaP wafers, and GaN wafers as constituent components.

Claims

1. A polishing agent composition for polishing a polishing object containing a group III-V compound as a constituent component. The polishing agent composition contains colloidal silica, an oxidizing agent, an oxidation promoter, a stabilizer, and water. The oxidation promoter is used to promote the oxidation reaction of the oxidizing agent on the surface of the polishing object. The stabilizer is used to control the promotion of the oxidation reaction of the oxidation promoter on the surface of the polishing object. The pH of the polishing agent 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 inorganic acid metal salt is any one of iron nitrate or iron sulfate. The stabilizer is a polycarboxylic acid. The polycarboxylic acid is malonic acid.

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

3. The polishing agent composition according to claim 1. Wherein, The oxidizing agent is a peroxide, permanganic acid or its salt, chromic acid or its salt, peroxy acid or its salt, halogen oxyacid or its salt, and mixtures thereof.

4. The polishing agent composition according to claim 1. Wherein, The oxidizing agent is hydrogen peroxide.

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

0.

6. A polishing method using a polishing agent composition, Characterized in that, The polishing agent composition according to any one of claims 1 to 5 is used to polish a polishing object containing a group III-V compound as a constituent component.

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