Abrasive composition and polishing method using the abrasive composition

Abstract

The present invention provides a polishing agent composition which expedites a mirror polishing process by means of the polishing rate or the like and improves smoothness and flatness of the wafer surface of a semiconductor wafer after the mirror polishing, thereby enabling mirror finish with high processing accuracy, and which exhibits excellent storage stability.　This polishing agent composition is used for polishing of a polishing object that contains, as a constituent, a group III to V compound; and this polishing agent composition is provided with colloidal silica, an oxidant, a pro-oxidant for accelerating the oxidation reaction at the surface of the polishing object by means of the oxidant, a stabilizer for controlling the accelerating effect of the pro-oxidant on the oxidation reaction at the surface of the polishing object, and water.

Description

[Technical Field]

[0001] The present invention relates to an abrasive composition and a polishing method using the abrasive composition, and more particularly to an abrasive composition used to mirror-polish the surface of a compound semiconductor wafer containing a III-V group compound such as gallium arsenide (GaAs), indium phosphide (InP), gallium phosphide (GaP), or gallium nitride (GaN) as a component, and a polishing method using the abrasive composition. [Background technology]

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

[0003] Semiconductor wafers are generally made by thinly slicing single crystals of III-V compounds, lapping them, and then performing various processing steps such as etching and polishing, followed by a final polishing step to complete the finish.

[0004] Final polishing, which corresponds to the final process (finishing process) for semiconductor wafers, is a process for smoothing the wafer surface of the semiconductor wafer and finishing it to a mirror finish. For example, a polishing pad is attached to a rotatable circular surface plate, and a polishing liquid prepared in advance is dropped onto the pad surface (polishing surface) of the polishing pad. The polishing pad is rotated while pressing the unpolished semiconductor wafer against the pad surface, thereby polishing the wafer surface through chemical and mechanical actions.

[0005] Polishing of semiconductor wafers has traditionally been performed in two stages: primary polishing (rough polishing) and secondary polishing (mirror-finish polishing). For example, known methods include a polishing method in which, during the primary polishing of semiconductor wafers, polishing is first performed using abrasive grains with large particle sizes, followed by polishing using abrasive grains with small particle sizes (see Patent Document 1); a polishing method using an abrasive with a distinctive abrasive grain shape and particle size distribution, and in particular using sodium dichloroisocyanurate as an oxidizing agent (see Patent Document 2); and a polishing method in which, during the primary polishing of GaAs wafers, polishing solutions with different compositions are used for the pre- and post-polishing stages (see Patent Document 3). Thus, various techniques have been adopted to precisely mirror-finish the wafer surface of semiconductor wafers.

[0006] In particular, after mirror polishing of semiconductor wafers, additional layers are formed on the mirror surface by epitaxial growth. Therefore, the processing accuracy (finish accuracy) of the mirror polishing by the final polishing is extremely important, and it is required to form a wafer surface that is excellent in smoothness and flatness with few irregularities, small waviness, and few surface abnormalities such as pits. [Prior art documents] [Patent documents]

[0007] [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 [Problem to be solved by the invention]

[0008] However, the polishing methods and polishing solutions (abrasive compositions) used in the above-mentioned Patent Documents 1 to 3 require long processing times, making it difficult to speed up the polishing process, or they may not be able to fully meet the required processing precision for mirror polishing. In addition, the methods disclosed in Patent Documents 2 and 3 that use sodium dichloroisocyanurate as an oxidizing agent have a significant effect on the storage stability of the polishing solution itself, and the polishing rate is likely to decrease over time, making it difficult to use for long periods of time.

[0009] In view of the above circumstances, an object of the present invention is to provide an abrasive composition which accelerates mirror polishing processing, such as the removal rate, improves the smoothness and flatness of the wafer surface of a semiconductor wafer after mirror polishing, enables mirror finishing with high processing accuracy, and has excellent storage stability, and to provide a polishing method using the abrasive composition. [Means for solving the problem]

[0010] As a result of intensive research aimed at solving the above-mentioned problems, the inventors of the present application have found that polishing using an abrasive composition prepared by containing specific components can speed up mirror polishing of semiconductor wafers, and have thus completed the present invention described below.

[0011] [1] A polishing compound composition for polishing an object to be polished, which contains a III-V group compound as a constituent, comprising colloidal silica, an oxidizing agent, an oxidation promoter for promoting an oxidation reaction of the surface of the object to be polished by the oxidizing agent, a stabilizer for controlling the promoting action of the oxidation reaction of the surface of the object to be polished by the oxidation promoter, and water. The stabilizer is at least one selected from the group consisting of polycarboxylic acids and polyaminocarboxylic acids, and has a pH (25°C) in the range of 0.1 to 6.0. Abrasive composition.

[0012] [2] The abrasive composition according to [1], wherein the III-V compound is at least one selected from the group consisting of gallium arsenide, gallium phosphide, indium phosphide, indium arsenide, aluminum arsenide, indium gallium arsenide compounds, indium gallium phosphide compounds, aluminum gallium arsenide compounds, indium aluminum gallium arsenide compounds, gallium nitride, gallium antimony compounds, and indium antimony compounds.

[0013] [3] The polishing compound composition according to [1] or [2], wherein the oxidizing agent is a peroxide, permanganic acid or a salt thereof, chromic acid or a salt thereof, peroxoacid or a salt thereof, halogen oxoacid or a salt thereof, oxyacid or a salt thereof, or a mixture thereof.

[0014] [4] The polishing compound composition according to any one of [1] to [3], wherein the oxidizing agent is hydrogen peroxide.

[0015] [5] The polishing compound composition according to any one of [1] to [4], wherein the pro-oxidant is either an inorganic acid metal salt or an organic acid metal salt.

[0016] [6] The polishing compound composition according to [5], wherein the inorganic acid metal salt is either iron nitrate or iron sulfate.

[0018] [ 7 The polycarboxylic acid is either malonic acid or citric acid. 1 ] The abrasive composition according to claim 1.

[0020] [ 8 ] [1] to [ 7 a polishing method using the polishing compound according to any one of claims 1 to 4, wherein the polishing compound is a compound of the group III-V. [Effects of the Invention]

[0021] The polishing compound of the present invention is characterized by containing an oxidizing agent, an oxidation promoter, and a stabilizer, and by using the polishing method of the present invention in which a semiconductor wafer is polished with the polishing compound of the present invention, mirror polishing excellent in flatness and smoothness can be performed at a high polishing rate. Furthermore, the polishing compound can also exhibit the effect of excellent storage stability over a long period of time. DETAILED DESCRIPTION OF THE INVENTION

[0022] The following describes embodiments of the present invention. The present invention is not limited to the following embodiments, and changes, modifications, and improvements can be made without departing from the scope of the invention.

[0023] 1. Abrasive composition The polishing compound of one embodiment of the present invention contains colloidal silica, an oxidizing agent, an oxidation promoter, a stabilizer, and water, and is prepared by mixing these materials in a predetermined ratio. Although the polishing compound of this embodiment has excellent storage stability, it is preferable that after preparation as a polishing compound, it is used for polishing semiconductor wafers such as GaAs wafers, InP wafers, GaP wafers, and GaN wafers as soon as possible. For example, it is preferable to use it for polishing within 48 hours after preparation of the polishing compound, and more preferably, it is used for polishing within 24 hours after preparation.

[0024] 1.1 Colloidal silica The colloidal silica used as a material in the polishing compound composition of this embodiment preferably has an average particle size (D50) in the range of 10 to 200 nm, and more preferably an average particle size (D50) 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, which may prevent smooth polishing. If the average particle size (D50) of the colloidal silica exceeds 200 nm, scratches may occur on the substrate. Here, the average particle size (D50) of the colloidal silica is calculated by analysis based on the results of observation using a transmission electron microscope (TEM) (details will be described later).

[0025] Colloidal silica is known to have various shapes, such as spherical, confetti-shaped (particulate with protrusions on the surface), and irregular shapes, and the primary particles are monodispersed in water to form a colloid. Colloidal silica of various shapes can be used as a material for the abrasive composition of this embodiment.

[0026] The colloidal silica used as the material can be produced by conventionally known production 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 grows colloidal silica particles by condensing the raw material in an aqueous solution; the alkoxysilane method, which uses a tetraalkoxysilane such as tetraethoxysilane as a raw material and grows colloidal silica particles by condensing the raw material with an acid or alkali through hydrolysis in a solvent containing a water-soluble organic solvent such as alcohol; or a method of synthesizing colloidal silica by reacting metal silicon with water in the presence of an alkali catalyst. The water glass method is preferred in terms of production cost. The colloidal silica used in the polishing compound composition of this embodiment can be produced by appropriately using these synthesis methods.

[0027] In the polishing compound of this embodiment, the content (content) of colloidal silica contained in the polishing compound is preferably in the range of 1 to 50 mass%, more preferably 2 to 40 mass%. If the content of colloidal silica is less than 1 mass%, the polishing resistance between the substrate and the polishing pad during polishing increases, and polishing may not proceed smoothly. If the content of colloidal silica exceeds 50 mass%, the colloidal silica may be prone to gelation.

[0028] 1.2 Oxidizing agents The oxidizing agent used as a material in the polishing compound composition of this embodiment may be a peroxide, permanganic acid or a salt thereof, chromic acid or a salt thereof, peroxoacid or a salt thereof, halogen oxoacid or a salt thereof, oxyacid or a salt thereof, or a mixture of two or more of these.

[0029] More specifically, examples include hydrogen peroxide, sodium peroxide, barium peroxide, potassium peroxide, potassium permanganate, metal salts of chromate, metal salts of dichromate, persulfuric acid, sodium persulfate, potassium persulfate, ammonium persulfate, peroxophosphoric acid, sodium peroxoborate, performic acid, peracetic acid, hypochlorous acid, sodium hypochlorite, calcium hypochlorite, etc. In particular, those using hydrogen peroxide, persulfuric acid and its salts, and hypochlorous acid and its salts are preferred, and the use of hydrogen peroxide is even more preferred.

[0030] The oxidizing agent functions to oxidize the surface of semiconductor wafers such as GaAs wafers, forming an oxide layer, facilitating the polishing of the semiconductor wafers to be polished. Furthermore, it also functions to oxidize polishing waste such as arsenic compounds that is generated and discharged during polishing of semiconductor wafers, thereby preventing deterioration of the working environment.

[0031] In the polishing compound of this embodiment, the content (content) of the oxidizing agent contained in the polishing compound is preferably in the range of 0.01 to 10.0 mass%, more preferably 0.1 to 5.0 mass%. If the content of the oxidizing agent is less than 0.01 mass%, the polishing rate may decrease. If the content of the oxidizing agent is more than 10.0 mass%, the surface roughness of the polished substrate may deteriorate.

[0032] 1.3 Prooxidants The oxidation promoter used as a material in the polishing compound of this embodiment may be an inorganic acid metal salt or an organic acid metal salt, with the use of an inorganic acid metal salt being particularly preferred.

[0033] More specifically, inorganic acid metal salts include iron salts, copper salts, silver salts, and manganese salts of nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, etc. For example, those using iron(III) nitrate, iron(III) sulfate, iron(II) sulfate, iron(III) chloride, or iron(II) chloride are preferred, and those using iron(III) nitrate are particularly preferred. These inorganic acid metal salts can be used in either anhydrous or hydrated form.

[0034] Examples of organic acid metal salts include metal salts of polycarboxylic acids and metal salts of polyaminocarboxylic acids. More specifically, examples of polycarboxylic acid metal salts include metal salts of oxalic acid, malonic acid, succinic acid, maleic acid, phthalic acid, citric acid, etc., and examples of polyaminocarboxylic acid metal salts include metal salts of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminediacetic acid, triethylenetetraminehexaacetic acid, etc. Iron salts, copper salts, silver salts, manganese salts, etc. of these organic acids can be used.

[0035] The pro-oxidant has the effect of accelerating the oxidation reaction of the semiconductor wafer caused by the oxidizing agent, thereby making it easier to polish the semiconductor wafer.

[0036] In the polishing compound of this embodiment, the content (content) of the pro-oxidant contained in the polishing compound 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 pro-oxidant is less than 0.01 mass%, the removal rate may decrease and the surface roughness of the polished substrate may deteriorate. If the content of the pro-oxidant exceeds 10.0 mass%, the effect of the pro-oxidant reaches a plateau, which is economically disadvantageous.

[0037] 1.4 Stabilizers The stabilizer used as a material in the polishing compound composition of this embodiment can be at least one selected from the group consisting of phosphoric acid, phosphorous acid, organic phosphonic acid, polycarboxylic acid, and polyaminocarboxylic acid. Specific examples of polycarboxylic acids include oxalic acid, malonic acid, succinic acid, maleic acid, phthalic acid, and citric acid. Specific examples of polyaminocarboxylic acids include ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminediacetic acid, and triethylenetetraminehexaacetic acid. Alkali metal salts of these compounds may also be used.

[0038] On the other hand, specific examples of organic phosphonic acids include 2-aminoethylphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotri(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.

[0039] Among the above, those using phosphoric acid, 1-hydroxyethylidene-1,1-diphosphonic acid, malonic acid, or citric acid are preferred, and those using malonic acid or citric acid are particularly preferred.

[0040] The stabilizer has the effect of suppressing the promotion of the oxidation reaction of semiconductor wafers by the pro-oxidant. This makes it possible to control the progress of the oxidation reaction caused by the oxidant and the pro-oxidant. Therefore, after preparation of the polishing compound composition, the oxidation reaction on the surface of the object to be polished can proceed slowly. As a result, the action of the polishing compound composition can be exerted for a long period of time, and the storage stability of the polishing compound composition can be maintained. This has the effect of allowing the polishing of semiconductor wafers to proceed stably and smoothly for a long period of time.

[0041] In the polishing compound of this embodiment, the content (content) of the stabilizer contained in the polishing compound 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 compound, which may deteriorate the stability of the polishing compound over time. If the content of the stabilizer exceeds 10.0 mass%, the effect of the stabilizer reaches a plateau, which is economically disadvantageous.

[0042] 1.5 water The water used as a material for the polishing compound of this embodiment is not particularly limited as long as it is pure water, ultrapure water, distilled water, or the like from which ions and suspended solids have been removed.

[0043] 1.6 Physical properties of abrasive compositions The pH (25°C) of the polishing compound of this embodiment is preferably in the range of 0.1 to 6.0, more preferably in the range of 0.5 to 5.0. The pH of the polishing compound can be adjusted by the content of the pro-oxidant and stabilizer. Furthermore, an acidic or basic compound can be added as needed to adjust the pH. If the pH (25°C) of the polishing compound is less than 0.1, corrosion of the polishing machine and surrounding equipment may occur. If the pH (25°C) of the polishing compound exceeds 6.0, gelation of the colloidal silica may occur more easily, potentially resulting in a deterioration in the surface roughness of the polished substrate.

[0044] 2. Object to be polished The semiconductor wafer to be polished with the polishing compound of this embodiment contains a III-V compound as a constituent component and is thinly sliced ​​gallium arsenide (GaAs) or indium phosphide (InP). Furthermore, the III-V compound is selected from the group consisting of gallium phosphide (GaP), indium arsenide (InAs), aluminum arsenide (AlAs), indium gallium arsenide (InGaAs), indium gallium arsenide phosphide (InGaAsP), aluminum gallium arsenide (AlGaAs), indium aluminum gallium arsenide (InAlGaAs), gallium nitride (GaN), gallium antimony compound (GaSb), and indium antimony compound (InSb). The semiconductor wafer to be polished (III-V compound semiconductor wafer) contains at least one of these III-V compounds as a constituent component.

[0045] 3. Polishing method using abrasive composition A polishing method using the polishing compound of one embodiment of the present invention (hereinafter simply referred to as "polishing method") is carried out, in which a semiconductor wafer containing a III-V compound as a component is polished using the polishing compound of this embodiment. Here, the polishing method comprises two stages (steps): a primary polishing and a secondary polishing performed after the primary polishing, both of which have the properties of chemical polishing and mechanical polishing.

[0046] The primary polishing step in the polishing method is primarily intended to increase the polishing speed during the polishing process, in other words, to improve the efficiency of the polishing process, and to ensure the flatness of the semiconductor wafer. Therefore, it is a relatively high component of mechanical polishing. On the other hand, the secondary polishing step in the polishing method is primarily intended to provide a final polishing to the semiconductor wafer surface, achieving a mirror finish by removing scratches, cloudiness, processing distortion, etc., from the wafer surface, resulting in a perfect mirror finish. Therefore, it is a relatively high component of chemical polishing.

[0047] Here, in the secondary polishing, for the purpose of achieving a perfect mirror finish, a two-layer structure is often used, for example, in which a polishing pad has a base layer made of polyester fiber and a urethane foam surface layer on the base layer. Furthermore, after the above-mentioned secondary polishing, an etching process may be carried out to remove any deposits remaining on the wafer surface of the semiconductor wafer and to remove the oxide film on the wafer surface, and a film formation process may be carried out to form a film on the wafer surface by epitaxial growth. Here, the polishing compound composition of this embodiment can be used when applying the polishing method of this embodiment to semiconductor wafers, and can be used in either stage (process) of the above-mentioned primary polishing or secondary polishing.

[0048] In the above, a polishing pad having a two-layer structure comprising a base layer made of polyester fiber and a urethane foam surface layer is exemplified as the polishing pad used in the secondary polishing, but the present invention is not limited to this, and conventionally known materials made of nonwoven fabric, polyurethane foam, porous resin, non-porous resin, etc. may be appropriately selected and used. Furthermore, in order to promote the supply of the abrasive composition to the polishing pad or to ensure that a certain amount of the abrasive composition remains on the polishing pad, the surface of the polishing pad may be grooved in a grid, concentric circle, spiral, or other pattern. [Example]

[0049] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In addition to the following examples, various modifications and improvements can be made to the present invention based on the knowledge of those skilled in the art, as long as they do not deviate from the spirit of the present invention.

[0050] (Preparation of abrasive composition) Using the materials listed in Table 1 below, 3 ~ 11、13、15、 17. Reference examples 1~5,The polishing compound compositions of Comparative Examples 1 to 11 were mixed together so as to contain the contents (mass %) shown in Table 1, and the resulting mixture was prepared. reference Example 1, 3 , 4 , 5 The abrasive compositions of Examples 4, 13, 15, and 17 were the same, the abrasive compositions of Comparative Examples 1, 6, 8, and 10 were the same, and the abrasive compositions of Comparative Examples 4, 7, 9, and 11 were the same. 3 ~10, 13、15、 17. Reference examples 1~5, The polishing compound compositions of Comparative Examples 1 to 3, 6, 8, and 10 were subjected to the polishing test immediately after preparation as a polishing compound, while the polishing compound compositions of Comparative Examples 1 to 3, 6, 8, and 10 were subjected to the polishing test after foaming had subsided. Furthermore, the polishing compound of Example 11 was subjected to the polishing test two hours after preparation as a polishing compound, and the polishing compound of Comparative Example 5 was subjected to the polishing test two hours after foaming had subsided because foaming had subsided after preparation as a polishing compound.

[0051] Since the stabilizer content in the polishing compound composition was adjusted to be constant in mol%, the mass % values ​​in Tables 1 to 6 reflect the magnitude of the molecular weight of each stabilizer. In Tables 1 and 2, "HEDP" refers to 1-hydroxyethylidene-1,1-diphosphonic acid, EDTA refers to ethylenediaminetetraacetic acid, and EDTA iron refers to ethylenediaminetetraacetic acid iron salt.

[0052] [Table 1]

[0053] (colloidal silica particle size) The particle size (Heywood diameter) of colloidal silica was measured as the Heywood diameter (diameter equivalent to a circle with a projected area) by taking a photograph of the field of view at 100,000 times magnification using a transmission electron microscope (TEM) (JEOL Ltd., JEM2000FX (200 kV) transmission electron microscope), and analyzing this photograph using analysis software (Mountec Co., Ltd., Mac-View Ver. 4.0). The average particle size of colloidal silica was determined by analyzing the diameters of approximately 2,000 colloidal silica particles using the method described above, and calculating the particle size at which the cumulative particle size distribution (cumulative volume basis) from the small particle size side constitutes 50% using the same analysis software (Mountec Co., Ltd., Mac-View Ver. 4.0). This average particle size (D50) was calculated.

[0054] (1) GaAs substrate polishing Example 3 ~11, Reference examples 1, 2, The polishing conditions for the polishing test of the object to be polished using the polishing compound compositions prepared as Comparative Examples 1 to 5 are as follows: The results of the polishing test conducted under these polishing conditions are shown in Tables 2 and 3 below.

[0055] (GaAs substrate polishing conditions) Polishing equipment: Single-sided polishing machine, surface plate diameter 350mm Polishing target: 3-inch GaAs substrate Polishing pad: Hard urethane IC1400 with grooves Polishing pressure: 200g / cm 2 Plate rotation speed: 60 rpm Polishing time: 10min Abrasive compound supply amount: 1-way supply, flow rate 40 ml / min

[0056] (GaAs substrate polishing rate ratio) The weight of the 3-inch GaAs substrate to be polished (hereinafter simply referred to as "GaAs substrate") was measured before and after the polishing test, and the polishing rate was calculated from the weight difference. The polishing rate ratio is shown as a relative value when the polishing rate value of Comparative Example 1 is set to 1 (reference). A larger value of the polishing rate ratio indicates a higher polishing rate and higher productivity.

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

[0058] (GaAs substrate surface roughness (Sa)) After the polishing test, the surface roughness (Sa) of the GaAs substrate surface was measured using the above-mentioned scanning white light interference microscope in a measurement range of 102 μm×102 μm.

[0059] [Table 2]

[0060] (Considerations on GaAs substrates) As shown in Table 2, the polishing compound of Comparative Example 1 does not contain a stabilizer, which is an essential component of the polishing compound of the present invention. Therefore, a large amount of bubbles was generated immediately after the preparation of the polishing compound, making practical handling difficult. However, the above performance evaluation was carried out on the prepared polishing compound. The polishing test itself was carried out after the generation of bubbles had subsided.

[0061] As shown in the results in Table 2 above, the polishing rate value for the polishing compound of Comparative Example 1 was higher than that of Examples 3, 4, and Reference Examples 1 and 2 The polishing rate of the polishing compound of Example 1 is less than half of that of Example 1, and the surface roughness (Sa) of the substrate is 3, 4, and Reference Examples 1 and 2 It was confirmed that the polishing performance was significantly worsened for the polishing compound of . Furthermore, although gloss was observed in the central part of the substrate surface, cloudiness occurred in the peripheral part of the substrate. In addition, multiple visible scratches were also observed.

[0062] As shown in Table 2, the polishing compound of Comparative Example 2 is the polishing compound of the present invention. 3, 4, and Reference Examples 1 and 2This polishing compound composition uses nitric acid instead of the stabilizer used in the polishing compound composition of Example 1. Therefore, a large amount of bubbles is generated immediately after the preparation of the polishing compound composition, making it difficult to handle in practice, but the above performance evaluation was carried out on the prepared polishing compound composition. The polishing test itself was carried out after the generation of bubbles had subsided.

[0063] As shown in the results in Table 2 above, the polishing rate value for the polishing compound of Comparative Example 2 was higher than that of Examples 3, 4, and Reference Examples 1 and 2 It was found that the removal rate was lower than that of the polishing compound (a). On the other hand, the substrate surface roughness and the condition of the substrate surface were both good. As mentioned above, since a large amount of bubbles was generated immediately after preparation, the storage stability of the polishing compound was evaluated as follows. The results are shown in Table 3 below.

[0064] [Table 3]

[0065] As shown in the results in Table 3 above, in Comparative Example 5, the polishing test was performed after 2 hours had passed since the generation of bubbles had subsided after preparation of the polishing compound prepared in Comparative Example 2, and it was found that the polishing rate was reduced to half compared to Comparative Example 2, in which polishing was performed immediately after the generation of bubbles had subsided after preparation. This indicates poor storage stability. On the other hand, in Example 11, the polishing test was performed after 2 hours had passed since preparation of the polishing compound prepared in Example 4, and it was found that the polishing performance was almost equivalent to that of the polishing compound of Example 4 and that the storage stability was excellent.

[0066] As shown by the results in Table 2 above, the polishing compound of Comparative Example 3 is a polishing compound of the present invention, which is an example. 3, 4, and Reference Examples 1 and 2 This is an example in which acetic acid was used instead of the stabilizer used in the polishing compound of Example 1, and although gloss was observed on the surface of the substrate after the polishing test, multiple scratches were visually confirmed and the surface roughness value was also significantly deteriorated. 3, 4, and Reference Examples 1 and 2In the case of Example 1, gloss was observed on the substrate surface after the polishing test, no scratches were visually observed, and the surface roughness value was also significantly improved compared to Comparative Example 3.

[0067] As shown by the results in Table 2 above, the polishing compound of Comparative Example 4 is an example that does not contain an oxidation promoter, which is an essential component of the polishing compound of the present invention, and compared to the polishing compounds of Examples 4 to 7 corresponding to Comparative Example 4, it was found that the polishing rate was lower, haze was observed on the substrate surface after the polishing test, and the surface roughness results were significantly lower. In contrast, in the cases of Examples 4 to 7 that satisfy the requirements of the polishing compound of the present invention, an improved polishing rate was observed, gloss was observed on the substrate surface after the polishing test, and the surface roughness results were good.

[0068] The polishing compound of Example 8 has a higher content (concentration) of colloidal silica than the polishing compound of Example 4, the polishing compound of Example 9 has a higher content (concentration) of hydrogen peroxide, an oxidizing agent, than the polishing compound of Example 4, and the polishing compound of Example 10 has a higher content (concentration) of a pro-oxidant than the polishing compound of Example 4. All of these polishing compounds of Examples 8 to 10 exhibit good polishing performance.

[0069] (2) InP substrate polishing Example 1 3, Reference example 3 The polishing conditions for the polishing test of the object to be polished using the polishing compound compositions prepared as Comparative Examples 1, 2, and 3 are as follows: The results of the polishing test under these polishing conditions are shown in Table 4 below.

[0070] (InP substrate polishing conditions) Polishing equipment: Single-sided polishing machine, surface plate diameter 360mm Polishing target: 2-inch InP substrate Polishing pad: Nonwoven SUBA800 without grooves Polishing pressure: 200g / cm 2 Plate rotation speed: 60 rpm Polishing time: 20min Abrasive compound supply amount: Circulation, flow rate 200 ml / min

[0071] (InP substrate polishing rate ratio) The weight of the 2-inch InP substrate to be polished (hereinafter simply referred to as "InP substrate") was measured before and after the polishing test, and the polishing rate was calculated from the weight difference. The polishing rate ratio is shown as a relative value with the value of Comparative Example 6 set to 1 (reference). A larger value of the polishing rate ratio indicates a higher polishing rate and higher productivity.

[0072] (InP substrate surface condition and InP substrate surface roughness (Sa)) The state of the substrate surface and the substrate surface roughness (Sa) were measured in the same manner as for the GaAs substrate.

[0073] [Table 4]

[0074] (Considerations on InP substrates) As shown in Table 4, the polishing compound of Comparative Example 6 does not contain a stabilizer, which is an essential component of the polishing compound of the present invention. Therefore, bubbles were generated immediately after the preparation of the polishing compound, making it difficult to handle in practice, but the above-mentioned performance evaluation was carried out on the prepared polishing compound. The polishing test itself was carried out after the generation of bubbles had subsided.

[0075] As shown in the results of Table 4 above, the polishing rate value of the polishing compound of Comparative Example 6 was 100% higher than that of Example 1. 3 and Reference Example 3 In contrast, Example 1, which satisfies the conditions of the polishing compound of the present invention, is less than half of the above value, and scratches are observed on the substrate surface. 3 and Reference Example 3 The polishing rate is high and no scratches are observed on the substrate surface.

[0076] As shown by the results in Table 4 above, the polishing compound of Comparative Example 7 is an example that does not contain a pro-oxidant, which is an essential component in the polishing compound of the present invention. 3 and Reference Example 3 In contrast to the polishing compound of Example 1, which satisfies the conditions of the polishing compound of the present invention, the polishing rate is low and scratches are observed on the substrate surface. 3 and Reference Example 3 The polishing rate is high and no scratches are observed on the substrate surface.

[0077] (3) GaP substrate polishing Example 1 5, Reference example 4 The polishing conditions for the polishing test of the object to be polished using the polishing compound compositions prepared as Comparative Examples 1, 2, and 3 are as follows: The results of the polishing test under these polishing conditions are shown in Table 5 below.

[0078] (GaP substrate polishing conditions) Polishing equipment: Single-sided polishing machine, surface plate diameter 360mm Polishing target: 2-inch GaP substrate Polishing pad: Nonwoven SUBA800 without grooves Polishing pressure: 200g / cm 2 Plate rotation speed: 60 rpm Polishing time: 20min Abrasive compound supply amount: Circulation, flow rate 200 ml / min

[0079] (GaP substrate polishing rate ratio) The weight of the 2-inch GaP substrate (hereinafter simply referred to as "GaP substrate") to be polished was measured before and after the polishing test, and the polishing rate was calculated from the weight difference. The polishing rate ratio is shown as a relative value with the value of Comparative Example 8 set as 1 (reference). A larger value of the polishing rate ratio indicates a higher polishing rate and higher productivity.

[0080] (GaP substrate surface condition and GaP substrate surface roughness (Sa)) The state of the substrate surface and the substrate surface roughness (Sa) were measured in the same manner as for the GaAs substrate and the InP substrate.

[0081] [Table 5]

[0082] (Considerations on GaP substrates) As shown in Table 5, the polishing compound of Comparative Example 8 does not contain a stabilizer, which is an essential component of the polishing compound of the present invention. Therefore, bubbles were generated immediately after the preparation of the polishing compound, making it difficult to handle in practice, but the above-mentioned performance evaluation was carried out on the prepared polishing compound. The polishing test itself was carried out after the generation of bubbles had subsided.

[0083] As shown in the results of Table 5 above, the polishing rate of the polishing compound of Comparative Example 8 was higher than that of Example 1. 5 and Reference Example 4 The surface roughness (Sa) is lower than that of Example 1. 5 and Reference Example 4 In contrast, Example 1, which satisfies the conditions of the polishing compound of the present invention, is higher than 5 and Reference Example 4 The polishing rate is high and the surface roughness is low.

[0084] As shown by the results in Table 5 above, the polishing compound of Comparative Example 9 is an example that does not contain a pro-oxidant, which is an essential component in the polishing compound of the present invention. 5 and Reference Example 4 In comparison with the polishing compound of Example 1, which satisfies the conditions of the polishing compound of the present invention, the polishing rate is low, the surface roughness is high, and scratches are observed on the substrate surface. 5 and Reference Example 4 The polishing rate is high, the surface roughness is low, and no scratches are observed.

[0085] (4) GaN substrate polishing Example 1 7, Reference example 5 The polishing conditions for the polishing test of the object to be polished using the polishing compound compositions prepared as Comparative Examples 10 and 11 are as follows: The results of the polishing test performed under these polishing conditions are shown in Table 6 below.

[0086] (GaN substrate polishing conditions) Polishing equipment: Single-sided polishing machine, surface plate diameter 360mm Polishing target: 2-inch GaN substrate Polishing pad: Nonwoven SUBA800 without grooves Polishing pressure: 500g / cm 2 Plate rotation speed: 60 rpm Polishing time: 120min Abrasive compound supply amount: Circulation, flow rate 200 ml / min

[0087] (GaN substrate polishing rate ratio) The weight of the 2-inch GaN substrate (hereinafter simply referred to as "GaN substrate") to be polished was measured before and after the polishing test, and the polishing rate was calculated from the weight difference. The polishing rate ratio is shown as a relative value with the value of Comparative Example 10 set to 1 (reference). A larger value of the polishing rate ratio indicates a higher polishing rate and higher productivity.

[0088] (GaN substrate surface condition and GaN substrate surface roughness (Sa)) The state of the substrate surface and the substrate surface roughness (Sa) were measured in the same manner as for the GaAs substrate, InP substrate, and GaP substrate.

[0089] [Table 6]

[0090] (Considerations on GaN substrates) As shown in Table 6, the polishing compound of Comparative Example 10 does not contain a stabilizer, which is an essential component of the polishing compound of the present invention. Therefore, bubbles were generated immediately after the preparation of the polishing compound, making it difficult to handle in practice, but the above-mentioned performance evaluation was carried out on the prepared polishing compound. The polishing test itself was carried out after the generation of bubbles had subsided.

[0091] As shown in the results of Table 6 above, the polishing rate of the polishing compound of Comparative Example 10 was higher than that of Example 1. 7 and Reference Example 5 The surface roughness (Sa) is lower than that of Example 1. 7 and Reference Example 5In contrast, Example 1, which satisfies the conditions of the polishing compound of the present invention, is higher than 7 and Reference Example 5 The polishing rate is high and the surface roughness is low.

[0092] As shown by the results in Table 6 above, the polishing compound of Comparative Example 11 is an example that does not contain a pro-oxidant, which is an essential component in the polishing compound of the present invention. 7 and Reference Example 5 In contrast to the polishing compound of Example 1, which satisfies the conditions of the polishing compound of the present invention, the polishing rate is low and the surface roughness is high. 7 and Reference Example 5 has a high polishing rate and low surface roughness.

[0093] As described above, by using the polishing compound of the present invention and carrying out a polishing method using the polishing compound of the present invention, the storage stability of the polishing compound can be improved, and stable polishing of objects to be polished can be carried out over a long period of time. Furthermore, the polishing rate of semiconductor wafers such as GaAs wafers, InP wafers, GaP wafers, and GaN wafers can be improved, and the substrate surface roughness after polishing can be improved, resulting in semiconductor wafers with a glossy substrate surface in a good condition. [Industrial Applicability]

[0094] The polishing compound of the present invention and the polishing method using the polishing compound can be used for primary polishing or secondary polishing of electronic components used in various electronic devices, such as semiconductor devices and elements, etc. In particular, they can be suitably used for polishing compound semiconductor wafers containing III-V group compounds as constituent components, such as GaAs wafers, InP wafers, GaP wafers, and GaN wafers.

Claims

1. An abrasive composition for polishing an object to be polished, which contains a III-V group compound as a constituent component, Colloidal silica and an oxidizing agent; an oxidation promoter for promoting an oxidation reaction of the surface of the object to be polished by the oxidizing agent; a stabilizer for controlling the promoting action of the oxidation promoter on the surface of the object to be polished; Water and Equipped with The stabilizer is at least one selected from the group consisting of polycarboxylic acids and polyaminocarboxylic acids, A polishing composition having a pH (25°C) in the range of 0.1 to 6.

0.

2. The III-V compound is 2. The polishing compound according to claim 1, wherein the polishing compound is at least one selected from the group consisting of gallium arsenide, gallium phosphide, indium phosphide, indium arsenide, aluminum arsenide, indium gallium arsenic compounds, indium gallium phosphide compounds, aluminum gallium arsenic compounds, indium aluminum gallium arsenic compounds, gallium nitride, gallium antimony compounds, and indium antimony compounds.

3. The oxidizing agent is 3. The polishing compound according to claim 1, wherein the polishing compound is a peroxide, permanganic acid or a salt thereof, chromic acid or a salt thereof, peroxoacid or a salt thereof, halogen oxoacid or a salt thereof, oxyacid or a salt thereof, or a mixture thereof.

4. The oxidizing agent is 4. The polishing compound according to claim 1, wherein the polishing agent is hydrogen peroxide.

5. The pro-oxidant is 5. The polishing compound according to claim 1, wherein the polishing compound is either an inorganic acid metal salt or an organic acid metal salt.

6. The inorganic acid metal salt is 6. The abrasive composition according to claim 5, which is either iron nitrate or iron sulfate.

7. The polycarboxylic acid is 2. The polishing composition according to claim 1, wherein the acid is either malonic acid or citric acid.

8. A polishing method using the abrasive composition according to claim 1, for polishing an object containing a III-V compound as a constituent component.

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