JP7409820B2 - Polishing method and polishing liquid for InP semiconductor material - Google Patents

Description

The present invention relates to a polishing method and polishing liquid for efficiently polishing one surface of an InP semiconductor material to a mirror surface.

BACKGROUND ART InP (indium phosphide) single crystal wafers, which have a larger lattice constant than gallium arsenide or gallium phosphide, are known as substrates for semiconductor devices. InP semiconductor materials such as InGaAs, AlInAs, InGaAsP, and AlGaInAs can be epitaxially grown, so these materials can be used to produce, for example, semiconductor lasers, optical modulators, optical waveguides, light emitting diodes, and light receiving devices. InP semiconductor materials are attracting attention as materials for optical communication devices such as elements.

As described in Patent Document 1, one method for polishing one surface of a semiconductor substrate to make it flat is a polishing method called CMP (Chemical Mechanical Polishing) method. In this CMP method, a wafer is pressed against a polishing pad such as a non-woven cloth or a foam pad attached to a surface plate and forced to rotate, and a slurry (fine powder) containing fine abrasive grains (free abrasive grains) is applied to the wafer. For example, polishing is performed by flowing a thick suspension (dispersed in a liquid such as an alkaline aqueous solution). According to such a CMP method, relatively highly accurate polishing is performed due to the synergistic effect of chemical polishing using a liquid component and mechanical polishing using abrasive grains.

Japanese Patent Application Publication No. 2004-025415

However, compared to GaN semiconductor substrates, InP semiconductor materials are brittle and easily cracked, so it is not possible to use a polishing load exceeding 15 kPa. There is a problem in that a polishing efficiency, that is, a polishing rate cannot be obtained for semiconductor materials.

The present invention has been made against the background of the above-mentioned circumstances, and its purpose is to provide a method for polishing an InP semiconductor material that can obtain polishing efficiency without increasing the polishing load.

As a result of continuing intensive research to develop a polishing method for such InP semiconductor materials, the present inventor found that by adding an oxidizing agent to the polishing liquid used for polishing and changing the pH of the polishing liquid, the polishing tool becomes It has been found that the polishing efficiency for InP semiconductor material can be significantly increased without increasing the pressure. The present invention was made based on this idea.

The gist of the first invention is as follows: (a) One surface of an InP semiconductor material is a polishing pad provided with abrasive grains in continuous holes formed in a base resin, and a polishing liquid containing no abrasive grains. (b) The polishing liquid contains 1 to 50% by weight of orthoperiodic acid as an oxidizing agent, and when using an acid pH adjuster, hydrochloric acid. (c) and has a hydrogen ion concentration of pH 0.3 to 6.9.

According to the first invention, one surface of the InP semiconductor material is polished using a polishing pad provided with polishing abrasive grains in continuous holes formed in a base material resin and a polishing liquid containing no polishing grains. In the polishing method, the polishing liquid contains 1 to 50% by weight of orthoperiodic acid as an oxidizing agent, contains hydrochloric acid when using an acid pH adjuster, and has a pH of 0.3 to 6. Since it has a hydrogen ion concentration of 9.9, higher polishing efficiency can be obtained for InP semiconductor materials than when using a polishing liquid that does not contain an oxidizing agent.

The gist of the second invention is that since the polishing liquid has a hydrogen ion concentration of pH 0.3 to 2.2, it is less effective against InP semiconductor materials than when the pH is around 6.9. The same or better surface roughness can be obtained.

The gist of the third invention is that since the polishing liquid has a hydrogen ion concentration of pH 0.3 to 1.3, the polishing liquid has a hydrogen ion concentration of pH 0.3 to 1.3. Surface roughness is obtained.

The gist of the fourth invention is that since the polishing liquid has a hydrogen ion concentration of pH 1.3 to 2.2, the surface of the InP semiconductor material is Roughness is reduced and a smooth surface is obtained.

The gist of the fifth invention is that since the polishing liquid contains hydrochloric acid as an acid pH adjuster, a strong acidity of pH 2.2 or less can be easily obtained.

The gist of the sixth invention is that since the polishing liquid contains iminodiacetic acid as an oxidation promoter, the surface roughness of the InP semiconductor material is improved.

The gist of the seventh invention is that since the polishing liquid contains 1 to 10% by weight of orthoperiodic acid, the polishing efficiency for InP semiconductor materials is increased.

The gist of the eighth invention is that since the polishing liquid contains 0.01 to 0.25 mol/l of potassium permanganate, the polishing efficiency for InP semiconductor material is increased.

The gist of the ninth invention is (a) a polishing method for polishing one surface of an InP semiconductor material using a polishing pad provided with abrasive grains in continuous holes formed in a base resin; (b) The polishing liquid contains 1 to 50% by weight of orthoperiodic acid as an oxidizing agent , and also contains hydrochloric acid when using an acid pH adjuster , ( c) It has a hydrogen ion concentration of pH 0.3 to 6.9.

According to the ninth invention, one surface of the InP semiconductor material is polished using a polishing pad provided with polishing abrasive grains in continuous holes formed in the base material resin and a polishing liquid containing no polishing grains. In this case, the polishing liquid contains 1 to 50% by weight of orthoperiodic acid as an oxidizing agent, and when using an acid pH adjuster, contains hydrochloric acid, and has a hydrogen ion concentration of pH 0.3 to 6.9. Therefore, higher polishing efficiency can be obtained for InP semiconductor materials than when using a polishing liquid that does not contain an oxidizing agent.

1 is a perspective view conceptually showing the configuration of a polishing apparatus that implements a polishing method according to an application example of the present invention. 2 is an enlarged schematic diagram illustrating the surface structure of the polishing pad shown in FIG. 1. FIG. A chart showing the composition, pH, and polishing test results (polishing rate (μm/min) and surface roughness Ra (nm)) of 13 types of polishing liquids used in polishing tests using the same polishing equipment as in Figure 1. be. 4 is a bar graph showing polishing rates for test samples for each of the 13 types of polishing liquids in FIG. 3. FIG. 4 is a bar graph showing surface roughness due to polishing of test samples for each of the 13 types of polishing liquids in FIG. 3. FIG. FIG. 4 is a diagram showing the pH and polishing rate of each of the 13 types of polishing liquid in FIG. 3 in two-dimensional coordinates showing the pH and polishing rate of the polishing liquid. 4 is a diagram showing the pH and surface roughness of each of the 13 types of polishing liquids in FIG. 3 in two-dimensional coordinates showing the pH of the polishing liquid and the polishing rate. FIG.

Hereinafter, one application example of the present invention will be described in detail with reference to the drawings.

FIG. 1 conceptually shows, with the frame removed, the main parts of a polishing apparatus 10 for performing polishing by CMP (Chemical Mechanical Polishing) method to which an example of the present invention is applied. There is. In FIG. 1, a polishing apparatus 10 is provided with a polishing surface plate 12 rotatably supported around its vertical rotation axis C1, and the polishing surface plate 12 is driven by a surface plate drive motor 13. As a result, it is rotationally driven in the direction of one rotation shown by the arrow in the figure. A polishing pad 14 is attached to the upper surface of this polishing surface plate 12, that is, the surface against which the object to be polished (InP semiconductor material) 16 is pressed.

On the other hand, at a position eccentric from the rotational axis C1 on the polishing surface plate 12, there is a workpiece holding member (carrier) 18 that holds the object 16 to be polished, such as an InP wafer, on its lower surface by suction or by using a holding frame or the like. The workpiece holding member 18 is supported so as to be rotatable around an axis C2 and movable in the direction of the rotational axis C2, and the workpiece holding member 18 is supported by a workpiece drive motor (not shown) or by the rotational moment received from the polishing surface plate 12. It is designed to be rotated in the direction of rotation shown by the arrow in FIG.

The object to be polished 16 is held on the lower surface of the workpiece holding member 18, that is, the surface facing the polishing pad 14, and the object to be polished 16 is pressed against the polishing pad 14 with a predetermined load by the workpiece holding member 18. ing. Further, a drip nozzle 22 and a spray nozzle 24 are provided near the workpiece holding member 18 of the polishing apparatus 10, and a polishing liquid (lubricant) 20, which is an oxidizing aqueous solution sent from a tank (not shown), is used for the polishing process. It is designed to be supplied onto a surface plate 12.

It should be noted that the polishing apparatus 10 is arranged such that it is rotatable around a rotation axis parallel to the rotation axis C1 of the polishing surface plate 12 and movable in the direction of the rotation axis and in the radial direction of the polishing surface plate 12. An adjustment tool holding member (not shown) and a polishing body adjustment tool (conditioner) such as a diamond wheel (not shown) attached to the lower surface of the adjustment tool holding member, that is, the surface facing the polishing pad 14, are provided as necessary. It is being This adjustment tool holding member and the polishing body adjustment tool attached thereto are pressed against the polishing pad 14 while being rotationally driven by an adjustment tool drive motor (not shown), and are reciprocated in the radial direction of the polishing surface plate 12. As a result, the polishing surface of the polishing pad 14 is adjusted so that the surface condition of the polishing pad 14 is always maintained in a state suitable for polishing.

During the polishing process using the CMP method using the polishing apparatus 10, the polishing surface plate 12 and the abrasive grain-containing polishing pad (LHA pad) 14 attached thereto, the workpiece holding member 18 and the workpiece holding member 18 held on the lower surface thereof. The polishing liquid 20 is applied to the polishing pad 14 from the dropping nozzle 22 and the spray nozzle 24 while the polished object 16 is rotated around the respective rotation axes by the surface plate drive motor 13 and the workpiece drive motor. The object to be polished 16 held by the work holding member 18 is pressed against the polishing pad 14 while being supplied onto the surface. By doing so, the surface to be polished of the object to be polished 16, that is, the surface facing the polishing pad 14, is exposed to the chemical polishing action of the polishing liquid 20 and is contained in the polishing pad 14 and is removed from the polishing pad 14. The surface is polished flat by the mechanical polishing action of self-supplied abrasive grains 26. For the polishing abrasive grains 26, for example, silica having an average grain size of about 80 nm is used.

The polishing pad 14 stuck on the polishing surface plate 12 is an abrasive-containing polishing pad made of epoxy resin or PES resin and having independent or continuous pores containing abrasive grains 26, for example. It has dimensions of approximately 300 (mm) in diameter and 5 (mm) in thickness.

FIG. 2 shows an example of such an abrasive grain-containing polishing pad, which includes a base resin 32 having communicating holes 30, and the communicating holes 30 of the base resin 32 are filled with a part of the base resin 32. The abrasive grains 26 are formed into a disk shape and include a large number of abrasive grains 26 that are fixed or partially separated from the base resin 32. This abrasive-containing polishing pad is composed of, for example, about 32% by volume of abrasive grains 26, about 33% by volume of base resin 32, and communicating holes 30 occupying the remaining volume. FIG. 2 is a schematic diagram showing the structure of the polishing pad 14 enlarged using a scanning electron microscope. A large number of abrasive grains 26 are held within the communicating holes 30. The base material resin 32 and the abrasive grains 26 are fixed to each other by a necessary and sufficient bonding force. The polishing pad 14 of this embodiment enables polishing by the CMP method by supplying a polishing liquid 20 that does not contain free abrasive grains, without using a slurry containing colloidal silica or the like.

The polishing liquid 20 contains at least one of 1 to 50% by weight of orthoperiodic acid and 0.01 to 0.1 mol/l of potassium permanganate as an oxidizing agent, and hydrochloric acid as an acid pH adjuster, It has a hydrogen ion concentration with a pH of 0.3 to 6.9.

The abrasive grains 26 preferably include silica, but also include at least one of other abrasive grains, such as ceria, alumina, zirconia, titania, manganese compounds, barium carbonate, chromium oxide, and iron oxide. may be used. As the silica, for example, fumed silica (silica fine particles obtained by burning silicon tetrachloride, chlorosilane, etc. at high temperature in the presence of hydrogen and oxygen) is suitably used. The average particle size of the polishing abrasive grains 26 is preferably 0.005 to 3.0 (μm), more preferably 0.005 to 1.0 (μm), and more preferably 0.02 to 0.6 (μm). , more preferably 0.08 to 0.5 (μm), still more preferably 0.08 to 0.3 (μm). For example, if the average particle diameter of the abrasive grains 26 exceeds 3.0 (μm), polishing scratches are likely to occur on the object to be polished 16 due to the abrasive grains 26 liberated from the base resin 32 during the polishing process described later. Become. Furthermore, if the average particle diameter of the polishing abrasive grains 26 is less than 0.005 (μm), the polishing abrasive grains 26 tend to aggregate, and polishing scratches are likely to occur on the object to be polished in the polishing process described below.

The particle size of the abrasive grains 26 is measured by a laser diffraction/scattering method, for example, using a particle size/particle size distribution measuring device Microtrac MT3300 manufactured by Nikkiso Co., Ltd., and the average particle size refers to the particle size. It is the arithmetic mean of the diameter. The particle size below the measurement limit of the laser diffraction/scattering method described above is measured by a dynamic light scattering method using, for example, a particle size/particle size distribution measuring device Nanotrack UPA-EX250 manufactured by Nikkiso Co., Ltd.

During polishing in the polishing apparatus 10 configured as described above, the polishing surface plate 12 and the polishing pad 14 attached thereto, the workpiece holding member 18 and the object to be polished 16 held on the lower surface thereof, An oxidizing polishing liquid 20 such as an aqueous solution of potassium permanganate is applied to the polishing pad 14 from the dropping nozzle 22 while being rotated around the respective rotation axes by the surface plate drive motor 13 and a workpiece drive motor (not shown). While being supplied onto the surface of the polishing pad 14, the object to be polished 16 held by the work holding member 18 is pressed against the surface of the polishing pad 14. By doing so, the surface to be polished of the object 16 to be polished, that is, the opposing surface in contact with the polishing pad 14, is exposed to the chemical polishing action of the polishing liquid 20 and the polishing abrasive grains 26 self-supplied by the polishing pad 14. The surface is polished flat by mechanical polishing action.

[Experiment example]
Examples of experiments conducted by the present inventors will be described below. First, using an apparatus configured similarly to the polishing apparatus 10 shown in FIG. 1 and using a free abrasive polishing pad made of hard polyurethane and abrasive grains under the free abrasive polishing conditions shown below, , using orthoperiodic acid and/or potassium permanganate for pH, and using 12 types of polishing liquids whose pHs were adjusted to differ from each other, as shown in FIG. Polishing tests were conducted on samples of a common object to be polished, which was an InP single crystal plate with a thickness of 350 μm.

[Polishing test conditions]
Polishing equipment: Engis High Press EJW-380
Polishing pad: hard polyurethane pad, or
Abrasive grain-containing polishing pad (LHA pad)
Outer diameter 300mm x thickness 2mm
Polishing pad rotation speed: 90 rpm
Polished object (sample): InP single crystal plate Shape of polished object: Outer diameter 2 inches, thickness 350 μm
Polished object rotation speed: 90 rpm
Polishing load (pressure): 14kPa (142gf/cm ² )
Polishing liquid supply amount: 10ml/min
Polishing time: 10min
Conditioner: SD#400 (metal bond wheel containing #400 diamond abrasive grains)

Figure 3 shows the polishing pad and polishing liquid composition, hydrogen ion concentration and pH, and polishing test results (polishing rate PR (μm/min) and surface roughness Ra (nm)) are shown, respectively.

FIG. 4 is a bar graph showing the polishing rate of the object to be polished for each of the 12 types of polishing methods in FIG. 3, and FIG. 5 is a bar graph showing the surface roughness of the test sample by polishing for each of the 12 types of polishing methods in FIG. It is a bar graph. Further, FIG. 6 is a diagram showing the pH and polishing rate of each of the 12 types of polishing liquid in FIG. 3 in two-dimensional coordinates showing the pH and polishing rate of the polishing liquid for each of the 12 types of polishing methods. FIG. 7 is a diagram showing the pH and surface roughness of each of the 12 types of polishing liquid in FIG. 3 in two-dimensional coordinates showing the pH and polishing rate of the polishing liquid for each of the 12 types of polishing methods. In addition, in FIG. 6, the ○ mark indicates the value for each comparative example method, and the numerical value appended to the ○ mark indicates the number of the comparative example method. Similarly, in FIG. 7, the ♦ mark indicates the value for each example method, and the numerical value appended to the ◆ mark indicates the number of the example method.

As is clear from FIGS. 3 and 6, Comparative Example Method 1 used in the polishing test using a polishing pad made of dense polyurethane resin contains 10% by weight of colloidal silica as free abrasive grains, but the oxidizing agent (orthoperiodic acid, potassium permanganate), acid pH adjuster (hydrochloric acid), oxidation promoter (iminodiacetic acid), alkaline pH adjuster (potassium hydroxide), lubricant (lauric acid), pH is 10.2. In the polishing test using Comparative Example Method 1, the polishing rate PR was 0.05 (μm/min), and sufficient polishing efficiency was not obtained for the InP single crystal plate. In Comparative Example Method 2, in which an LHA polishing pad was used instead of a polishing pad made of a dense polyurethane resin, and a polishing liquid containing no 10% by weight of colloidal silica as free abrasive grains was used, the polishing rate PR was 0.01. Therefore, the processing efficiency was even lower than that of Comparative Example Method 1. Moreover, Comparative Example Method 3 differs from Example Method 4 only in that it contains an alkaline Ph adjuster (potassium hydroxide) and a lubricant (lauric acid). Compared to Example Method 4, Example Method 3 had a higher pH, but the polishing rate PR was 0.04, which was an even lower value than Comparative Example Method 1.

On the other hand, as is clear from FIGS. 3 and 6, when polishing is performed using the LHA pad shown in FIG. 2, the pH of each grinding fluid ranges from 0.5 to 6. Regarding Example Methods 1 to 9 using polishing liquid 20 of No. 9, suitable polishing efficiency was obtained in which the polishing rate PR of Comparative Example Method 1 exceeded 0.05 μm/h. Further, among the polishing liquids 20 of Example Methods 1 to 9 having a pH of 0.5 to 6.9, Example Methods 1 to 7 and 9 use the polishing liquid 20 having a pH of 0.3 to 2.2. In this case, since the polishing liquid 20 has strong acidity, a stable high polishing efficiency can be obtained for the InP single crystal plate, similar to Example Method 8 using the polishing liquid 20 with a pH of around 6.9. ing. Among Example Methods 1 to 7 and 9, Example Methods 2, 3 and 5 use a polishing liquid having a pH of 0.3 to 1.3. Since the surface roughness is greater than that of Example Methods 4, 6, 7, and 9 using , this method is suitable for applications where large surface roughness is acceptable. On the contrary, Example Methods 4, 6, 7, and 9 using a polishing liquid with a pH of 1.3 to 2.2 are different from Example Method 2, which uses a polishing liquid with a pH of 0.3 to 1.3. Since the surface roughness Ra is small compared to No. 3 and No. 5, it is suitable for applications requiring a mirror surface with a small surface roughness Ra.

Since the polishing liquid 20 of Example Methods 5 to 7 and 9 contains 0.01 to 0.1N (normal) hydrochloric acid as an acid pH adjuster, it is easy to prepare a polishing liquid having strong acidity with a pH of 2.2 or less. A high polishing rate PR was obtained. Further, as compared with Example Method 6, Example Method 7 includes iminodiacetic acid, which is a key rate agent, as an oxidation promoter, and thus the surface roughness of the InP single crystal plate is improved.

In the polishing liquid 20 of Example Methods 1 to 7 and 9, since the polishing liquid contains 1 to 10% by weight of orthoperiodic acid, a low pH (strongly acidic) polishing liquid can be obtained. Polishing efficiency is improved. Furthermore, in the polishing liquid 20 of Example Methods 8 and 9, since the polishing liquid contains 0.01 to 0.25 mol/l of potassium permanganate as an oxidizing agent, the polishing efficiency for InP single crystal plates is increased. It will be done.

As described above, according to the polishing method of this embodiment and the polishing liquid 20 used therein, the polishing pad 14 which is an LHA pad is used, and the polishing liquid 20 contains orthoperiodic acid and permanganic acid as oxidizing agents. Since the polishing liquid 20 contains at least one of potassium and hydrochloric acid when an acid pH adjuster is used, the polishing liquid 20 further has a hydrogen ion concentration of pH 0.3 to 6.9. Compared to the case where a liquid is used, high polishing efficiency can be obtained for the object to be polished 16 (InP semiconductor material) at a low polishing load of about 14 kPa without increasing the polishing load.

Further, according to the polishing method of this embodiment and the polishing liquid 20 used therein, since the polishing liquid 20 has a hydrogen ion concentration of pH 0.3 to 2.2, when the pH is around 6.9, In comparison, a surface roughness equal to or higher than that of the object to be polished 16 (InP semiconductor material) can be obtained.

Further, according to the polishing method of this embodiment and the polishing liquid 20 used therein, since the polishing liquid 20 has a hydrogen ion concentration of pH 0.3 to 1.3, when the pH is 2.2 or more, In comparison, the surface roughness of the object to be polished 16 (InP semiconductor material) can be increased.

Further, according to the polishing method of this embodiment and the polishing liquid 20 used therein, since the polishing liquid 20 has a hydrogen ion concentration of pH 1.3 to 2.2, when the pH is 1.3 or less, In comparison, the surface roughness of the object to be polished 16 (InP semiconductor material) is reduced, and a smooth surface is obtained.

Further, according to the polishing method of this embodiment and the polishing liquid 20 used therein, since the polishing liquid 20 contains hydrochloric acid as an acid pH adjuster, a strong acidity with a pH of 2.2 or less can be easily obtained.

Further, according to the polishing method of this embodiment and the polishing liquid 20 used therein, since the polishing liquid 20 contains iminodiacetic acid as an oxidation promoter, the surface roughness of the object to be polished 16 (InP semiconductor material) is reduced. is improved.

Further, according to the polishing method of the present embodiment and the polishing liquid 20 used therein, since the polishing liquid 20 contains 1 to 10% by weight of orthoperiodic acid, polishing of the object to be polished 16 (InP semiconductor material) is possible. Efficiency is increased.

Further, according to the polishing method of this embodiment and the polishing liquid 20 used therein, since the polishing liquid 20 contains 0.01 to 0.25 mol/l of potassium permanganate, the object to be polished 16 (InP semiconductor polishing efficiency for materials) is increased.

Although one embodiment of the present invention has been described above, the present invention can also be applied to other aspects.

For example, a hard foamed polyurethane resin has been used as the base material resin 32, but other resins such as polyamide, polyamideimide, polyimide, polyacrylonitrile, polyvinylidene fluoride, cellulose acetate, polyvinyl alcohol, and polyurethane may also be used. It may include one.

The abrasive grains 26 preferably include silica, but other abrasive grains such as ceria, alumina, zirconia, titania, manganese compounds, barium carbonate, chromium oxide, and at least one of iron oxides are used. One containing one may be used. As the silica, for example, fumed silica (silica fine particles obtained by burning silicon tetrachloride, chlorosilane, etc. at high temperature in the presence of hydrogen and oxygen) is suitably used.

The average particle size of the polishing abrasive grains 26 is preferably 0.005 to 3.0 (μm), more preferably 0.005 to 1.0 (μm), and more preferably 0.02 to 0.6 (μm). , more preferably 0.08 to 0.5 (μm), still more preferably 0.08 to 0.3 (μm). For example, if the average particle size of the polishing abrasive grains 26 exceeds 3.0 (μm), polishing scratches are likely to occur on the object to be polished due to the polishing grains 26 liberated from the base material resin 32 during the polishing process described later. . Furthermore, if the average particle diameter of the polishing abrasive grains 26 is less than 0.005 (μm), the polishing abrasive grains 26 tend to aggregate, and polishing scratches are likely to occur on the object to be polished in the polishing process described below.

The particle size of the abrasive grains 26 is measured by a laser diffraction/scattering method, for example, using a particle size/particle size distribution measuring device Microtrac MT3300 manufactured by Nikkiso Co., Ltd., and the average particle size refers to the particle size. It is the arithmetic mean of the diameter. The particle size below the measurement limit of the laser diffraction/scattering method described above is measured by a dynamic light scattering method using, for example, a particle size/particle size distribution measuring device Nanotrack UPA-EX250 manufactured by Nikkiso Co., Ltd.

Although no other examples are given, the present invention can be used with various modifications without departing from the spirit thereof.

10: Polishing device 12: Polishing surface plate 14: Polishing pad 16: Polished object (InP semiconductor material)
20: Polishing liquid 26: Polishing abrasive grains 30: Communication holes 32: Base material resin

Claims (9)

A polishing method for polishing one surface of an InP semiconductor material using a polishing pad provided with abrasive grains in continuous holes formed in a base resin and a polishing liquid containing no abrasive grains, the method comprising:
The polishing liquid contains 1 to 50% by weight of orthoperiodic acid as an oxidizing agent, contains hydrochloric acid when using an acid pH adjuster, and has a hydrogen ion concentration of pH 0.3 to 6.9. A method for polishing an InP semiconductor material, characterized in that: 2. The method of polishing an InP semiconductor material according to claim 1, wherein the polishing liquid has a hydrogen ion concentration of pH 0.3 to 2.2. 2. The method of polishing an InP semiconductor material according to claim 1, wherein the polishing liquid has a hydrogen ion concentration of pH 0.3 to 1.3. 2. The method of polishing an InP semiconductor material according to claim 1, wherein the polishing liquid has a hydrogen ion concentration of pH 1.3 to 2.2. 5. The method of polishing an InP semiconductor material according to claim 1, wherein the polishing liquid contains 0.01 to 0.1N hydrochloric acid as an acid pH adjuster. The polishing liquid includes iminodiacetic acid as an oxidation promoter.
5. The method of polishing an InP semiconductor material according to claim 1, 2, or 4. 7. The method of polishing an InP semiconductor material according to claim 1, wherein the polishing liquid contains 1 to 10% by weight of orthoperiodic acid as an oxidizing agent. The polishing liquid includes 0.01 to 0.25 mol/l of potassium permanganate as an oxidizing agent.
The method for polishing an InP semiconductor material according to any one of claims 1, 2, 4 to 7. A polishing liquid applied to a polishing method of polishing one surface of an InP semiconductor material using a polishing pad provided with polishing abrasive grains in continuous holes formed in a base resin,
A polishing liquid comprising 1 to 50% by weight of orthoperiodic acid as an oxidizing agent and having a hydrogen ion concentration of pH 0.3 to 6.9.

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