JP7366341B2 - Etching method - Google Patents

Description

TECHNICAL FIELD The present invention relates to an etching method useful for manufacturing semiconductor devices, electronic devices, etc.

Semiconductor devices using gallium oxide (Ga ₂ O ₃ ), which has a large band gap, are attracting attention as next-generation switching elements that can achieve high voltage resistance, low loss, and high heat resistance, and are expected to be used in power semiconductor devices such as inverters. Application is expected. Moreover, due to its wide bandgap, it is also expected to be applied to light receiving and emitting devices such as LEDs and sensors. According to Non-Patent Document 1, the bandgap of gallium oxide can be controlled by mixing indium and aluminum individually or in combination, and constitutes an extremely attractive material system as an InAlGaO semiconductor. . Here, InAlGaO-based semiconductor refers to In _X Al _Y Ga _Z O ₃ (0≦X≦2, 0≦Y≦2, 0≦Z≦2, It can be viewed from a bird's-eye view as the same material system.

However, there is a problem in that gallium oxide cannot be easily etched even if it is subjected to an etching process using an etching solution such as HF. Techniques are known in which an etching target such as a substrate, a semiconductor film, or an insulating film is subjected to an etching process using a liquid material. For example, an etching process method using a spray method is generally known. . Among these, a method of etching an object to be etched by using an atomized liquid raw material (mist) has been studied. Furthermore, in recent years, patterns on the order of submicrons are formed in the manufacturing process of semiconductor devices, electronic devices, etc., which has led to the problem that, for example, it is difficult to cover steps even when using mist. Therefore, a processing method that is useful in manufacturing semiconductor devices, electronic equipment, etc. and that can control etching on an etching target at the nano-level has been awaited.

Patent Document 1 describes that an etching process is performed in which existing structures on the wafer are dissolved and removed by spraying a micro mist having an average particle size of 10 μm or less onto the surface of a semiconductor wafer. However, the etching method described in Patent Document 1 is still insufficient for etching gallium oxide, and an etching method that can satisfactorily etch gallium oxide has been desired.

Patent Document 2 describes a fine channel type mist etching apparatus, in which zinc oxide, etc. It is described that an etching process is performed on an object to be etched. However, with the etching method described in Patent Document 2, it is difficult to properly etch gallium oxide, and an industrially applicable etching method with a small amount of etching has been desired.

Japanese Patent Application Publication No. 2009-010033 Japanese Patent Application Publication No. 2011-181784

Kentaro Kaneko, “Growth and physical properties of corundum-structured gallium oxide mixed crystal thin films”, Kyoto University doctoral thesis, March 2013

SUMMARY OF THE INVENTION An object of the present invention is to provide an etching method capable of etching an object to be etched with industrial advantage.

As a result of intensive studies to achieve the above object, the inventors of the present invention have developed a method for etching an object to be etched using an etching solution. It has been found that even gallium oxide, which is difficult to etch, can be satisfactorily etched by etching with . It has also been found that such an etching treatment method can solve the above-mentioned conventional problems all at once.
Further, after obtaining the above knowledge, the present inventors conducted further studies and completed the present invention.

That is, the present invention relates to the following inventions.
[1] A method of etching an object to be etched using an etching liquid, the etching liquid containing bromine, and the etching process being carried out at a temperature higher than 200°C. Method.
[2] The etching method according to [1], wherein the object to be etched contains at least aluminum and/or gallium.
[3] The etching method according to [1] or [2], wherein the object to be etched contains at least gallium.
[4] The etching method according to any one of [1] to [3], wherein the object to be etched has a corundum structure.
[5] The etching method according to any one of [1] to [4] above, wherein the object to be etched contains gallium oxide.
[6] The etching treatment method according to any one of [1] to [5], wherein the etching treatment is performed at a temperature of 400° C. or higher.
[7] The etching treatment method according to any one of [1] to [6], wherein the etching treatment is performed using atomized droplets containing the etching solution.
[8] The etching processing method according to [7], wherein the atomized droplets atomize the etching liquid to suspend the droplets, and then are transported using a carrier gas.
[9] The etching method according to [8], wherein the carrier gas is an inert gas.
[10] A method of manufacturing a semiconductor device using an etching method, wherein the etching method is the etching method according to any one of [1] to [9].
[11] A method of manufacturing a product using an etching treatment method, wherein the etching treatment method is the etching treatment method according to any one of [1] to [9] above.

According to the etching method of the present invention, an object to be etched can be etched with industrial advantage.

FIG. 1 is a schematic configuration diagram of an etching processing apparatus used in Examples. FIG. 3 is a diagram showing the relationship between the etching amount and the concentration of hydrobromic acid in Examples. It is a figure which shows the microscopic image after the etching process in an Example. It is a figure which shows the microscopic image after the etching process in an Example. FIG. 2 is a cross-sectional view schematically showing an example of a metal oxide semiconductor field effect transistor (MOSFET) in a manufacturing example. FIG. 3 is a schematic cross-sectional view for explaining an example of a manufacturing process of a metal oxide semiconductor field effect transistor (MOSFET) in a manufacturing example. FIG. 2 is a cross-sectional view schematically showing an example of a junction barrier Schottky diode (JBS) in a manufacturing example. FIG. 3 is a schematic cross-sectional view for explaining an example of a manufacturing process of a junction barrier Schottky diode (JBS) in a manufacturing example.

The etching treatment method of the present invention is a method of etching an object to be etched using an etching solution, the etching solution containing bromine, and the etching treatment being performed at a temperature higher than 200°C. Features:

(etching solution)
The etching solution is not particularly limited as long as it contains bromine and can etch the object to be etched. Further, the etching solution may further contain an inorganic material or an organic material. In the present invention, it is preferable that the etching solution contains hydrogen bromide because the etching process can be performed better. Note that the solvent of the etching solution is not particularly limited, but is preferably an inorganic solvent, more preferably a polar solvent, and most preferably water. The concentration of the etching solution is not particularly limited, but it is preferably 5% or more, more preferably 10% or more, and most preferably 20% by volume based on the solvent of the etching solution. . The upper limit of the concentration is not particularly limited as long as atomization or droplet formation is possible.

(Object to be etched)
The object to be etched is not particularly limited as long as it can be etched using the etching solution. The material of the object to be etched is not particularly limited as long as it does not impede the object of the present invention, and may be any known material, such as an organic compound or an inorganic compound. The shape of the object to be etched may be any shape, and is effective for all shapes, such as plate shapes such as flat plates and disks, film shapes, fiber shapes, rod shapes, and column shapes. , prismatic, cylindrical, spiral, spherical, ring-shaped, etc. In the present invention, it is preferable that the object to be etched is in the form of a film. In an aspect of the present invention, the object to be etched preferably contains at least aluminum or/and gallium, more preferably contains an oxide containing aluminum or/and gallium, and more preferably contains an oxide containing aluminum oxide and/or gallium oxide. is even more preferred, and most preferably contains gallium oxide. Further, the object to be etched is preferably a crystal, more preferably has a corundum structure, a β-gallium structure, or a hexagonal structure, and most preferably has a corundum structure.

The object to be etched may be integrated with a substrate or the like, and in the present invention, it is preferably laminated on the substrate directly or via another layer. The substrate is not particularly limited as long as it can support the object to be etched. The material of the substrate is not particularly limited as long as it does not impede the object of the present invention, and may be a known substrate, an organic compound, or an inorganic compound. The shape of the substrate may be any shape, and is effective for all shapes, such as plate shapes such as flat plates and disks, fiber shapes, rod shapes, cylinder shapes, prismatic shapes, Examples include a cylindrical shape, a spiral shape, a spherical shape, a ring shape, etc., but a substrate is preferable in the present invention. The thickness of the substrate is not particularly limited in the present invention.

The substrate is not particularly limited as long as it has a plate shape and serves as a support for the object to be etched. The substrate may be an insulating substrate, a semiconductor substrate, or a conductive substrate, but it is preferable that the substrate is an insulating substrate and has a metal film on the surface. It is also preferable that it is a substrate. Preferably, the substrate includes, for example, a substrate having a corundum structure. The substrate material is not particularly limited and may be any known material as long as it does not impede the purpose of the present invention. The substrate having a corundum structure may be, for example, a substrate having at least part of its surface a substrate material having a corundum structure. Further, it may be a base substrate mainly composed of a substrate material having a corundum structure, and more specifically, for example, a sapphire substrate (preferably a c-plane sapphire substrate) or an α-type gallium oxide substrate can be mentioned. Here, the term "main component" means that the substrate material having the specific crystal structure preferably accounts for 50% or more, more preferably 70% or more, and still more preferably 90% of the total components of the substrate material in terms of atomic ratio. % or more, and may even be 100%.
The means for laminating the object to be etched on the base may be a known means.

In the present invention, the object to be etched is etched using the etching solution at a temperature higher than 200°C. The etching treatment means is not particularly limited as long as it is a means capable of etching the object to be etched using the etching solution. In the present invention, the etching process is preferably carried out using atomized droplets containing the etching solution, and more preferably carried out by causing the etching object to react with the atomized droplets containing the etching solution. preferable. The atomized droplets are not particularly limited as long as the etching solution is atomized or dropletized. It is preferable that the atomizing means or droplet forming means is a means for atomizing the etching solution, suspending the droplets, and generating atomized droplets. In the present invention, the means for generating atomized droplets is preferably an atomization means or a droplet formation means using ultrasonic waves. Atomized droplets obtained using ultrasound are preferable because they have an initial velocity of zero and float in the air.For example, rather than being sprayed like a spray, they can be suspended in space and transported as a gas. Since it is possible to atomize droplets, there is no damage due to collision energy, which is very suitable. In the present invention, it is preferable that the atomized droplets are those obtained by atomizing or forming droplets the etching liquid, and then conveying the etching liquid using a carrier gas. Further, the etching temperature is not particularly limited as long as it is higher than 200°C, but in the present invention, it is preferable that the etching temperature is 400°C or higher.

In the present invention, it is preferable to transport the atomized droplets using a carrier gas. The carrier gas is not particularly limited as long as it does not impede the purpose of the present invention, and suitable examples include oxygen, ozone, inert gases such as nitrogen and argon, and reducing gases such as hydrogen gas and forming gas. Can be mentioned. Further, the number of types of carrier gas may be one, but it may be two or more types, and a diluted gas with a lowered flow rate (for example, 10 times diluted gas, etc.) may be further used as the second carrier gas. Good too. Further, the number of locations where the carrier gas is supplied is not limited to one location, but may be two or more locations. The flow rate of the carrier gas is not particularly limited, but is preferably 0.01 to 20 L/min, more preferably 1 to 10 L/min. In the case of diluent gas, the flow rate of the diluent gas is preferably 0.001 to 2 L/min, more preferably 0.1 to 1 L/min.

The reaction may be any reaction as long as the object to be etched can be etched using the atomized droplets, and may include a chemical reaction or a thermal reaction due to heat. . In the present invention, the etching process is usually performed at a temperature higher than 200°C, but in the present invention, the temperature is preferably 350°C or higher, and more preferably 400°C or higher. In the present invention, even at such high temperatures, the object to be etched can be etched stably and favorably. The upper limit is not particularly limited as long as it does not impede the object of the present invention, but is preferably 1900°C or lower, more preferably 1400°C or lower. Further, the reaction may be carried out under any atmosphere including vacuum, non-oxygen atmosphere, reducing gas atmosphere and oxygen atmosphere, as long as the purpose of the present invention is not impaired. It is preferable to carry out under an atmosphere, and it is more preferable to carry out under an inert gas atmosphere. Further, although it may be carried out under any of atmospheric pressure, increased pressure, and reduced pressure, in the present invention, it is preferable to carry out under atmospheric pressure. Note that the etching amount can be set by adjusting the etching processing time.

The etching treatment method can be applied in the manufacturing process of various products, and is preferably used in the manufacturing process of semiconductor devices. Examples of the semiconductor device include a diode, a transistor, and a JBS. In addition to the semiconductor devices, the products include, for example, CPU-equipped electronic devices such as digital cameras, printers, projectors, personal computers, and mobile phones, electronic devices equipped with power supply units such as vacuum cleaners and irons, motors, drives, etc. Examples include mechanisms, electric vehicles, electric airplanes, small electric devices, and driving electronic devices such as MEMS.

Hereinafter, the present invention will be explained in more detail using an example of manufacturing a product (semiconductor device) by applying the etching method of the present invention to the manufacturing process of the product (semiconductor device), but the present invention is not limited to this. It is not something that will be done.

FIG. 5 is a cross-sectional view schematically showing a metal oxide semiconductor field effect transistor (MOSFET) manufactured by applying the etching method of the present invention. The MOSFET in FIG. 5 is a trench-type MOSFET, which includes an n-type semiconductor layer 131a, a first n+-type semiconductor layer 131b, a second n+-type semiconductor layer 131c, a gate insulating film 134, a gate electrode 135a, and a source electrode 135b. and a drain electrode 135c. A first n+ type semiconductor layer 131b with a thickness of 100 nm to 100 μm, for example, is formed on the drain electrode 135c, and an n- type semiconductor layer 131b with a thickness of 100 nm to 100 μm, for example, is formed on the first n+ type semiconductor layer 131b. A semiconductor layer 131a is formed. Furthermore, a second n+ type semiconductor layer 131c is formed on the n- type semiconductor layer 131a, and a source electrode 135b is formed on the second n+ type semiconductor layer 131c.

Further, in the n- type semiconductor layer 131a and the second n+ type semiconductor layer 131c, there are a plurality of depths that penetrate the second n+ type semiconductor layer 131c and reach halfway through the n- type semiconductor layer 131a. A trench groove is formed. A gate electrode 135a is buried in the trench via a gate insulating film 134 having a thickness of, for example, 10 nm to 1 μm.

FIG. 6 shows part of the manufacturing process of the MOSFET shown in FIG. For example, using a semiconductor structure as shown in FIG. 6(a), etching masks are provided in predetermined regions of the n- type semiconductor layer 131a and the second n+-type semiconductor layer 131c, and the etching mask is used as a mask to perform the present invention. As shown in FIG. 6(b), etching is performed using the etching method described above to form a trench with a depth reaching from the surface of the second n+ type semiconductor layer 131c to partway through the n- type semiconductor layer 131a. The etching solution and etching treatment conditions include the etching solution and etching treatment conditions described above.The n-type + type semiconductor layer 131c and the n- type semiconductor layer 131a are both made of α-Ga. ₂ O ₃ as a main component, the device containing α-Ga ₂ O ₃ can be further improved by etching using the etching method of the present invention using an etching solution containing bromine as the etching solution. It can be produced industrially advantageously.Next, as shown in FIG. 6(c), the side surfaces of the trench groove and After forming a gate insulating film 134 with a thickness of, for example, 50 nm to 1 μm on the bottom surface, an n-type gate electrode material 135a such as polysilicon is deposited in the trench groove using a CVD method, a vacuum evaporation method, a sputtering method, or the like. The thickness is formed to be less than the thickness of the semiconductor layer.

Then, by forming a source electrode 135b on the n+ type semiconductor layer 131c and a drain electrode 135c on the n+ type semiconductor layer 131b using known means such as a vacuum evaporation method, a sputtering method, or a CVD method, Power MOSFETs can be manufactured. Note that the electrode material of the source electrode and the drain electrode may be each known electrode material, and examples of the electrode material include Al, Mo, Co, Zr, Sn, Nb, Fe, Cr, Ta, and Ti. , Au, Pt, V, Mn, Ni, Cu, Hf, W, Ir, Zn, In, Pd, Nd or Ag or their alloys, tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO) ), a metal oxide conductive film such as indium zinc oxide (IZO), an organic conductive compound such as polyaniline, polythiophene or polypyrrole, or a mixture thereof.

FIG. 7 is a cross-sectional view schematically showing a junction barrier Schottky diode (JBS) manufactured by applying the etching treatment method of the present invention. The semiconductor device in FIG. 7 includes an n-type semiconductor layer 3 and an electrode (barrier electrode) 2 provided on the n-type semiconductor layer 3 and capable of forming a Schottky barrier between the n-type semiconductor layer 3 and the n-type semiconductor layer 3. and a barrier height larger than the Schottky barrier height of the electrode (barrier electrode) 2 provided between the electrode (barrier electrode) 2 and the n-type semiconductor layer 3 and between the n-type semiconductor layer 3 and the electrode (barrier electrode) 2. and a p-type semiconductor capable of forming a Schottky barrier. Note that the p-type semiconductor 1 is embedded in the n-type semiconductor layer 3.

Hereinafter, preferred manufacturing steps for the semiconductor device shown in FIG. 7 will be described using FIG. 8. FIG. 8A shows a stacked body in which an ohmic electrode 4 is stacked on a semiconductor substrate serving as an n-type semiconductor layer 3, and a plurality of trenches are formed on the opposite surface. Then, the surface of the laminate shown in FIG. 8(a) is etched using the etching method of the present invention, and then the surface of the laminate is etched using the photolithography method as shown in FIG. 8(b). , a p-type semiconductor 1 is formed in the trench of the n-type semiconductor layer 3. After obtaining the laminate shown in FIG. 8(b), an electrode (barrier electrode) 2 is formed on the p-type semiconductor 1 and the n-type semiconductor layer 3 using the dry method (preferably vacuum evaporation or sputtering) or the wet method. The laminate shown in FIG. 8(c) is obtained. The etching treatment method of the present invention can also be suitably used as a pretreatment before regrowth of each layer (semiconductor layer, insulator layer, etc.) of a semiconductor device in the manufacturing process of a semiconductor device.

Examples of the present invention will be described below, but the present invention is not limited thereto.

(Example 1)
1. Etching Processing Apparatus The etching processing apparatus 19 used in this example will be explained using FIG. The etching processing apparatus 19 in FIG. 1 includes a carrier gas source 22a that supplies a carrier gas, a flow rate control valve 23a that adjusts the flow rate of the carrier gas sent out from the carrier gas source 22a, and a carrier gas (dilution) that supplies the carrier gas. A carrier gas (dilution) source 22b, a flow rate adjustment valve 23b for adjusting the flow rate of the carrier gas (dilution) sent out from the carrier gas (dilution) source 22b, and a mist generation source 24 containing an etching solution 24a. A container 25 into which water 25a is placed, an ultrasonic vibrator 26 attached to the bottom of the container 25, an etching chamber 30, and a supply pipe 27 made of quartz that connects the mist source 24 to the film forming chamber 30. A hot plate (heater) 28 installed in the etching processing chamber 30 is provided. The object to be etched 20 is placed on the hot plate 28 . Further, the etching processing chamber 30 is provided with an exhaust port at a high position on the side wall, and is configured so that the mist stays around the object to be etched 20.

2. Preparation of Etching Solution Hydrobromic acid was mixed with ultrapure water at a volume ratio of 20%, and this was used as an etching solution.

3. Preparation for etching 2. The etching solution 24a obtained in the above was stored in the mist generation source 24. Next, as the object 20 to be etched, a c-plane sapphire substrate with a c-plane α-Ga ₂ O ₃ film formed on the surface is placed on a hot plate 28 , and the hot plate 28 is operated to raise the temperature of the object 20 to be etched. The temperature was raised to 365°C. Next, the flow rate control valves 23a and 23b are opened, and the flow rate of the carrier gas supplied from the carrier gas source 22a is set to 2.0 L/min, and the flow rate of the dilution gas supplied from the carrier gas (dilution) source 22b is set to 2.0 L/min. Each was adjusted to .0 L/min. Note that nitrogen was used as a carrier gas.

4. Etching process Next, the ultrasonic vibrator 26 is vibrated at 2.4 MHz, and the vibration is propagated to the raw material solution 24a through the water 25a, thereby atomizing the etching liquid 24a and forming a mist (atomized droplets) 24b. was generated. This mist 24b is introduced into the etching processing chamber 30 through the supply pipe 27 by the carrier gas, and the mist reacts on the etching object 20 at 365° C. under atmospheric pressure, thereby etching the etching object. No. 20 was etched. Processing time was 1 hour. After the etching process, the presence or absence of cracks was observed using a microscope. A microscopic image is shown in Figure 3. As is clear from FIG. 3, no cracks were generated even after the etching treatment. Note that the etching amount was 698 nm.

(Example 2)
Etching treatment was performed in the same manner as in Example 1, except that ultrapure water was mixed with hydrobromic acid at a volume ratio of 30%, and this was used as the etching solution. Further, the etching amount was 1277 nm.

(Comparative example 1)
Etching treatment was performed in the same manner as in Example 1, except that ultrapure water was mixed with hydrochloric acid at a volume ratio of 20%, and this was used as the etching solution. Further, the etching amount was 12 nm.

(Comparative example 2)
Etching treatment was performed in the same manner as in Example 1, except that ultrapure water was mixed with hydrochloric acid at a volume ratio of 30%, and this was used as the etching solution. Further, the etching amount was 13 nm.

(evaluation)
The etching amounts of the etching treatments performed in Examples 1 and 2 and Comparative Examples 1 and 2 were measured. Figure 2 shows the results.

(Example 3)
Etching treatment was performed in the same manner as in Example 2 except that the etching treatment temperature was 400°C. The etching amount was 1473 nm, and the etching condition was also good. As in Example 1, after the etching process, the presence or absence of cracks was observed under a microscope, and no cracks were found even after the etching process.

(Example 4)
Etching treatment was performed in the same manner as in Example 1, except that an r-plane sapphire substrate with an r-plane α-Ga ₂ O ₃ film formed on the surface was used as the object to be etched. The etching amount was 313 nm. The surface roughness (Ra) before and after the etching treatment was examined using AFM to evaluate the surface condition. As a result, the surface roughness (Ra) before etching treatment was 35.9 nm, while the surface roughness (Ra) after etching treatment was 28.4 nm. This shows that the surface smoothness was improved by the etching treatment.

(Example 5)
Etching treatment was performed in the same manner as in Example 4 except that the etching treatment temperature was 400°C. The etching amount was 380 nm. As in Example 1, after the etching treatment, the presence or absence of cracks was observed using a microscope. A microscopic image is shown in Figure 4. As is clear from FIG. 4, no cracks were generated even after the etching treatment. Furthermore, the amount of etching was larger than in Example 3.

(Example 6)
Etching treatment was performed in the same manner as in Example 5, except that ultrapure water was mixed with hydrobromic acid at a volume ratio of 30%, and this was used as the etching solution. The etching amount was 897 nm, and the etching condition was also good.

(Example 7)
Etching treatment was performed in the same manner as in Example 1, except that an m-plane sapphire substrate with an m-plane α-Ga ₂ O ₃ film formed on the surface was used as the object to be etched. The etching amount was 223 nm. As in Example 1, after the etching process, the presence or absence of cracks was observed under a microscope, and no cracks were found even after the etching process.

(Example 8)
Etching was carried out in the same manner as in Example 2, except that the etching temperature was 400°C and an m-plane sapphire substrate with an m-plane α-Ga ₂ O ₃ film formed on the surface was used as the etching target. processed. The etching amount was 696 nm, and the etching condition was also good. As in Example 1, after the etching process, the presence or absence of cracks was observed under a microscope, and no cracks were found even after the etching process.

(Example 9)
Etching was carried out in the same manner as in Example 2, except that the etching temperature was 400° C., and an a-plane sapphire substrate with an a-plane α-Ga ₂ O ₃ film formed on the surface was used as the etching target. processed. The etching amount was 305 nm, and the etching condition was also good.

(Comparative example 3)
Etching treatment was performed in the same manner as in Comparative Example 1, except that an m-plane sapphire substrate with an m-plane α-Ga ₂ O ₃ film formed on the surface was used as the etching target. The etching amount was 0 nm.

(Comparative example 4)
Etching treatment was performed in the same manner as in Comparative Example 2, except that an m-plane sapphire substrate with an m-plane α-Ga ₂ O ₃ film formed on the surface was used as the etching target. The etching amount was 0 nm.

(Comparative example 5)
Etching treatment was performed in the same manner as in Comparative Example 1, except that an r-plane sapphire substrate with an r-plane α-Ga ₂ O ₃ film formed on the surface was used as the etching target. The etching amount was 0 nm.

(Comparative example 6)
Etching treatment was performed in the same manner as in Comparative Example 2, except that an r-plane sapphire substrate with an r-plane α-Ga ₂ O ₃ film formed on the surface was used as the etching target. The etching amount was 0 nm.

(Comparative Example 7)
Etching treatment was performed in the same manner as in Comparative Example 1, except that an a-plane sapphire substrate with an a-plane α-Ga ₂ O ₃ film formed on the surface was used as the etching target. The etching amount was 0 nm.

(Comparative example 8)
Etching treatment was performed in the same manner as in Comparative Example 2, except that an a-plane sapphire substrate with an a-plane α-Ga ₂ O ₃ film formed on the surface was used as the etching object. The etching amount was 0 nm.

The etching method of the present invention can etch an object to be etched with industrial advantage, and therefore can be used in various manufacturing fields such as semiconductor devices and electronic devices.

1 p-type semiconductor 2 electrode (barrier electrode)
3 N-type semiconductor layer 4 Ohmic electrode 19 Etching processing device 20 Etching object 22a Carrier gas supply means 22b Carrier gas (dilution) supply means 23a Flow rate control valve 23b Flow rate control valve 24 Mist source 24a Etching liquid 25 Container 25a Water 26 Sonic transducer 27 Supply tube 28 Heater 30 Etching chamber 131a N- type semiconductor layer 131b First n+ type semiconductor layer 131c Second n+ type semiconductor layer 132 P-type semiconductor layer 134 Gate insulating film 135a Gate electrode 135b Source electrode 135c drain electrode

Claims (10)

A method of etching an object to be etched using an etching liquid, wherein the object to be etched has a corundum structure, the etching liquid contains bromine, and the etching process is performed at a temperature higher than 200°C. An etching treatment method characterized in that it is carried out with. The etching method according to claim 1, wherein the object to be etched contains at least aluminum and/or gallium. The etching method according to claim 1 or 2, wherein the object to be etched contains at least gallium. The etching method according to claim 1 , wherein the object to be etched contains gallium oxide. The etching treatment method according to any one of claims 1 to 4 , wherein the etching treatment is performed at a temperature of 400° C. or higher. The etching treatment method according to any one of claims 1 to 5 , wherein the etching treatment is performed using atomized droplets containing the etching solution. 7. The etching processing method according to claim 6 , wherein the atomized droplets are atomized by atomizing the etching liquid to float the droplets, and then transported using a carrier gas. The etching method according to claim 7 , wherein the carrier gas is an inert gas. A method of manufacturing a semiconductor device using an etching treatment method, wherein the etching treatment method is the etching treatment method according to any one of claims 1 to 8 . A method of manufacturing a product using an etching treatment method, wherein the etching treatment method is the etching treatment method according to any one of claims 1 to 8 .