Etching control method of groove-shaped structure and groove-shaped structure
By controlling the etching power gradually decreases in the semiconductor etching equipment, the problem of damage caused by plasma etching method to the GaN HEMT gate trough is solved, a flatter interface and lower leakage current are achieved, and the high-frequency performance of the device is improved.
Patent Information
- Application Number
- CN202311466217.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-06
- Publication Date
- 2025-05-09
AI Technical Summary
When etching the gate groove of GaN HEMT using plasma etching method, conventional methods cause damage to the gate groove surface, damage to the interface, and affect the characteristics of high-frequency devices.
By controlling the etching power in the semiconductor etching device to gradually decrease according to preset rules, the heavy group energy of the plasma is reduced, thereby reducing damage to the channel.
It effectively reduces damage to the deposition interface of the groove-shaped structure, improves the Schottky junction interface, reduces leakage current and Coulomb effect, and improves the working efficiency of the device.
Smart Images
Figure CN119965084A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of semiconductor device preparation, and in particular to an etching control method for a groove structure and a groove structure. Background Art
[0002] The high concentration and high mobility 2DEG (two-dimensional electron gas) in the channel layer gives GaN HEMT (gallium nitride high electron mobility transistor) a huge advantage in the field of millimeter wave radio frequency. Usually people reduce the gate capacitance by continuously shortening the gate length, thereby pursuing a higher operating frequency of the device. However, this will cause the device gate electrode's ability to regulate 2DEG to gradually weaken, and the short channel effect is obvious. Therefore, for millimeter wave devices, precise and low-damage etching of the GaN cap layer and AlGaN barrier layer in the gate groove area to control the ratio of the gate length Lg to the gate-to-channel distance tbr (Lg / tbr>15) has become a key technical step to eliminate the short channel effect.
[0003] Dry etching is the mainstream technology in the production process of millimeter-wave GaN HEMT. Dry etching technology is to ionize the reaction gas into ions and electrons with high reaction activity, and the highly active plasma produces physical bombardment and chemical reaction on the etching material.
[0004] Due to the stable chemical properties of GaN materials, the etching conditions require higher bias voltage, RF power and plasma density. These conditions will inevitably damage the barrier layer in the etched area during the etching process, thus introducing defects and impurities at the bombarded interface. When defects and impurities capture Schottky hot electrons, additional carrier Coulomb scattering effects will occur, resulting in a decrease in the mobility of the two-dimensional electron gas in the channel, which directly affects the channel current. In addition, the gate groove interface after etching is rougher, resulting in a decrease in the barrier height in the metal semiconductor contact, an increase in the Schottky leakage current, and some channel electrons obtaining enough energy to enter the buffer layer, causing an increase in the buffer layer leakage in the off state, reducing the efficiency of the device during operation.
[0005] When etching the gate groove using plasma etching, conventional etching uses a fixed-value input power RF source to etch the cap layer barrier layer, which causes damage to the gate groove surface, destroys the interface, and thus affects the device characteristics at high frequencies. Due to the good stability of the Ga-N bond, in order to achieve the purpose of physically bombarding the chemical bond to break it, it is first necessary to increase the ICP energy with high power. According to the point model of etching, after the surface Ga-N bond is broken, the etching begins normally. Since some ions and groups undergo continuous collisions during the etching process and obtain greater energy, etching damage will also be caused, and the damage depth is within a few nm; since the damage is cumulative, even if the RF power is very small, it will cause certain damage. Summary of the invention
[0006] The purpose of the present invention is to provide an etching control method and a groove structure of a groove structure, so as to provide a technical solution that can solve the problem that when a plasma etching method is used to etch a gate groove, a conventional etching method using a fixed value input power radio frequency source to etch a cap layer barrier layer causes damage to the gate groove surface, destroys the interface, and thus affects the device characteristics at high frequencies.
[0007] In a first aspect, the present invention discloses an etching control method for a groove structure, which is applied to a semiconductor etching device. The etching control method for the groove structure comprises the following steps:
[0008] Based on the groove structure to be etched, the etching power of the semiconductor etching equipment is set; wherein the groove structure to be etched is GaN material or / AlGaN material
[0009] During the etching process of the groove structure, the etching power of the semiconductor etching device is controlled to gradually change according to a preset rule, so that the groove structure obtained by etching meets the preset requirements.
[0010] In the case of adopting the above technical solution, it should be understood that in practice, due to the good stability of Ga-N bonds, in order to achieve the purpose of physically bombarding chemical bonds to break them, it is necessary to first increase the etching energy with high power. According to the point model of etching, after the surface Ga-N bonds are broken, the etching begins to proceed normally. Since some ions and groups undergo continuous collisions during the etching process and obtain greater energy, etching damage will also be caused, and the damage depth is within a few nm; since the damage is cumulative, even if the RF power is very small, it will cause certain damage. Based on this, in the etching process of the groove structure of the present invention, the etching power of the semiconductor etching equipment is controlled to be gradually reduced according to a preset rule to reduce the energy of the heavy groups of the plasma, thereby reducing the damage to the channel. In addition, the etching control method of the present invention uses a larger etching power to break the Ga-N bond of the material at the beginning of etching. Therefore, the etching of the groove structure can be effectively completed, and at the same time, the damage to the deposition interface of the groove structure can be reduced, thereby improving the Schottky junction interface, making the interface smoother, and improving the roughness. The barrier height in the channel tends to be consistent and can effectively avoid and isolate the occurrence of leakage. At the same time, it also avoids the non-ideal Coulomb effect caused by defects and impurities, so as to solve the technical problem that when etching the gate groove using a plasma etching method, the conventional etching method using a fixed value input power radio frequency source to etch the cap layer barrier layer causes damage to the gate groove surface, destroys the interface, and thus affects the device characteristics at high frequency.
[0011] Furthermore, the initial etching power of the semiconductor etching equipment includes: initial source power and initial radio frequency power of the semiconductor etching equipment.
[0012] Furthermore, during the etching process of the groove structure, controlling the etching power of the semiconductor etching device to gradually change from the initial etching power according to a preset rule so that the etching obtained meets the preset requirements includes:
[0013] During the etching process of the groove structure, the RF power of the semiconductor etching device is controlled to gradually decrease from the initial RF power, and the source power of the semiconductor etching device is controlled to remain unchanged, so that the etched structure meets the preset requirements.
[0014] Furthermore, during the etching process of the groove-shaped structure, controlling the etching power of the semiconductor etching device to gradually change according to a preset rule so that the groove-shaped structure obtained by etching meets the preset requirements includes:
[0015] During the etching process of the groove structure, the RF power of the semiconductor etching equipment is controlled to gradually decrease from the initial RF power, and the source power of the semiconductor etching equipment is controlled to gradually decrease from the initial source power, so that the etched groove structure meets the preset requirements.
[0016] Furthermore, the groove structure includes a gate trench structure, an isolation trench structure or a thin film grating structure.
[0017] Furthermore, the semiconductor etching equipment includes an inductively coupled plasma etching equipment, an electron cyclotron resonance plasma etching equipment or a reactive ion etching equipment.
[0018] Furthermore, during the etching process of the groove-shaped structure, the etching power of the semiconductor etching device is controlled to gradually change according to a preset rule so that the groove-shaped structure obtained by etching meets the preset requirements, and the etching control method of the groove-shaped structure also includes:
[0019] The surface oxide and the cap layer of the semiconductor structure are removed by using a removal gas, wherein the semiconductor structure is a structure for preparing the gate trench structure.
[0020] Furthermore, when the groove structure is a gate trench structure and the semiconductor etching equipment is the inductively coupled plasma etching equipment, the initial source power of the semiconductor etching equipment is set to 120W and the initial radio frequency power is set to 5W.
[0021] Furthermore, during the etching process of the groove-shaped structure, controlling the etching power of the semiconductor etching device to gradually change according to a preset rule so that the groove-shaped structure obtained by etching meets the preset requirements includes:
[0022] During the etching process of the groove structure, the etching power of the semiconductor etching equipment is controlled to be linearly reduced to 3W within the etching time, so that the groove structure obtained by etching meets the preset requirements.
[0023] In a second aspect, the present invention further provides a groove structure, wherein the groove structure is etched according to the etching control method of the groove structure to obtain
[0024] Compared with the prior art, the beneficial effects of the second aspect of the present invention are the same as the beneficial effects of the etching control method of the groove structure of the above technical solution, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:
[0026] Figure 1 A flowchart of a method for controlling etching of a groove structure provided by an embodiment of the present invention;
[0027] Figure 2 A schematic diagram showing that the source power remains unchanged and the power of the radio frequency source is gradually reduced during the etching process of a groove structure provided by an embodiment of the present invention;
[0028] Figure 3 A schematic diagram of synchronously reducing source power and radio frequency power during an etching process of a groove structure provided by an embodiment of the present invention;
[0029] Figure 4 The present invention provides a Schottky characteristic of a gate trench structure after variable power etching. DETAILED DESCRIPTION
[0030] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.
[0031] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The meaning of "several" is one or more, unless otherwise clearly and specifically defined.
[0032] The high concentration and high mobility 2DEG (two-dimensional electron gas) in the channel layer gives GaN HEMT (gallium nitride high electron mobility transistor) a huge advantage in the field of millimeter wave radio frequency. Usually people reduce the gate capacitance by continuously shortening the gate length, thereby pursuing a higher operating frequency of the device. However, this will cause the device gate electrode's ability to regulate 2DEG to gradually weaken, and the short channel effect is obvious. Therefore, for millimeter wave devices, precise and low-damage etching of the GaN cap layer and AlGaN barrier layer in the gate groove area to control the ratio of the gate length Lg to the gate-to-channel distance tbr (Lg / tbr>15) has become a key technical step to eliminate the short channel effect.
[0033] Dry etching is the mainstream technology in the production process of millimeter-wave GaN HEMT. Dry etching technology is to ionize the reaction gas into ions and electrons with high reaction activity, and the highly active plasma produces physical bombardment and chemical reaction on the etching material.
[0034] Due to the stable chemical properties of GaN materials, the etching conditions require higher bias voltage, RF power and plasma density. These conditions will inevitably damage the barrier layer in the etched area during the etching process, thus introducing defects and impurities at the bombarded interface. When defects and impurities capture Schottky hot electrons, additional carrier Coulomb scattering effects will occur, resulting in a decrease in the mobility of the two-dimensional electron gas in the channel, which directly affects the channel current. In addition, the gate groove interface after etching is rougher, resulting in a decrease in the barrier height in the metal semiconductor contact, an increase in the Schottky leakage current, and some channel electrons obtaining enough energy to enter the buffer layer, causing an increase in the buffer layer leakage in the off state, reducing the efficiency of the device during operation.
[0035] When etching the gate groove using plasma etching, conventional etching uses a fixed-value input power RF source to etch the cap layer barrier layer, which causes damage to the gate groove surface, destroys the interface, and thus affects the device characteristics at high frequencies. Due to the good stability of the Ga-N bond, in order to achieve the purpose of physically bombarding the chemical bond to break it, it is first necessary to increase the ICP energy with high power. According to the point model of etching, after the surface Ga-N bond is broken, the etching begins normally. Since some ions and groups undergo continuous collisions during the etching process and obtain greater energy, etching damage will also be caused, and the damage depth is within a few nm; since the damage is cumulative, even if the RF power is very small, it will cause certain damage.
[0036] Based on this, refer to Figure 1An embodiment of the present invention provides an etching control method for a groove structure, which is applied to a semiconductor etching device, wherein the semiconductor etching device may include an inductively coupled plasma etching (ICP) device, an electron cyclotron resonance plasma etching (ECR) device or a reactive ion etching (RIE) device.
[0037] Compared with electron cyclotron resonance plasma etching equipment and reactive ion etching equipment, the unique feature of inductively coupled plasma etching equipment is that it has two independent radio frequency sources, one for exciting ionization and generating plasma. The other is used to generate bias to make ions move toward the substrate, thus having better controllability. The plasma density generated by the ICP method is 1 to 2 orders of magnitude higher than that of conventional RIE technology, which is conducive to the breaking of Ga-N bonds and achieving high-rate and low-damage etching. At the same time, the working gas pressure is low, which is conducive to controlling morphology and anisotropy. ICP is currently the most widely used AlGaN / GaN HEMT gate trench etching technology.
[0038] The specific process of ICP is: free electrons collide with the reaction gas under the acceleration of the radio frequency electric field to ionize ions, and the ions bombard the substrate surface to assist chemical reactions, causing lattice damage, accelerating the desorption of reactants, removing non-volatile residues on the substrate surface, promoting chemical reactions on the substrate surface, enhancing adhesion, and breaking chemical bonds. At the same time, the recombination of ions and electrons proceeds synchronously, and finally reaches a balance between recombination and ionization. Inductive coupling forms a glow discharge, generating free radicals such as excited molecules, atoms, and atomic groups, which then react chemically with the etched material, and finally the ion bombardment of the etched material promotes the volatilization of the product.
[0039] In an embodiment of the present invention, the above-mentioned groove structure includes a gate trench structure (gate trench structure), an isolation trench structure or a thin film grating structure.
[0040] Reference Figure 1 The etching control method of the above-mentioned groove structure comprises the following steps:
[0041] S100, setting the initial etching power of the semiconductor etching device based on the groove structure to be etched and the material and structure; wherein the groove structure to be etched is GaN material or / AlGaN material.
[0042] Among them, in the embodiment of the present invention, the material of the groove structure to be etched is GaN material. It should be understood that due to the stable chemical properties of GaN material, the etching conditions require higher bias voltage, RF power and plasma density. Therefore, in order to etch the desired groove structure in the etched groove structure, in general, it is necessary to set the initial etching power higher to achieve the purpose of physically bombarding the chemical bonds of the GaN material to break them. It is also understood that the initial etching power is also related to the structure of the groove structure to be etched, for example, the etching size, etc. In practice, specific settings can be made according to the requirements of the groove structure to be etched, and the embodiment of the present invention does not make specific limitations on this.
[0043] In practice, the initial etching power of the semiconductor etching equipment includes: the initial source power and the initial radio frequency power of the semiconductor etching equipment.
[0044] S200, during the etching process of the groove-shaped structure, controlling the etching power of the semiconductor etching device to gradually decrease from the initial etching power according to a preset rule, so that the groove-shaped structure obtained by etching meets preset requirements.
[0045] In a specific embodiment, during the etching process of the groove structure, controlling the etching power of the semiconductor etching device to gradually change from the initial etching power according to a preset rule so that the etching obtained by etching meets the preset requirements includes:
[0046] During the etching process of the groove structure, the RF power of the semiconductor etching device is controlled to gradually decrease from the initial RF power, and the source power of the semiconductor etching device is controlled to remain unchanged, so that the etched structure meets the preset requirements.
[0047] Specifically, refer to Figure 2 During the etching process, the source power is kept constant and the power of the RF source is gradually reduced to avoid excessive damage accumulation, thereby reducing the initial energy of the plasma to reduce damage to the channel. The source power is controlled to remain at 120W, and the RF power is controlled to be gradually reduced from 5W to 3W in 60S.
[0048] In another specific embodiment, during the etching process of the groove-shaped structure, controlling the etching power of the semiconductor etching device to gradually change according to a preset rule so that the groove-shaped structure obtained by etching meets the preset requirements includes:
[0049] During the etching process of the groove structure, the RF power of the semiconductor etching equipment is controlled to gradually decrease from the initial RF power, and the source power of the semiconductor etching equipment is controlled to gradually decrease from the initial source power, so that the etched groove structure meets the preset requirements.
[0050] Specifically, refer to Figure 3 You can also gradually reduce the source power and RF power at the beginning of etching, control the source power to gradually decrease from 120W to 110W in 60S, and control the RF power to gradually decrease from 5W to 3W in 60S.
[0051] Based on the above implementation methods, when the above-mentioned groove structure is a gate groove structure, the embodiment of the present invention can effectively complete the etching of the gate groove, and at the same time can reduce the damage to the gate metal deposition interface, thereby improving the Schottky junction interface, making the interface smoother, and improving the roughness. The barrier height in the channel tends to be consistent and can effectively avoid and isolate the occurrence of leakage, and also avoid the non-ideal Coulomb effect caused by defects and impurities. The Schottky current characteristic curve of the gate groove is finally measured as follows: Figure 4 As shown, Z3 is the Schottky current characteristic curve of the gate groove measured by the prior art when the etching power remains unchanged during the etching process, and Z3 is the Schottky current characteristic curve of the gate groove measured by the embodiment of the present invention when the etching power gradually decreases during the etching process. Through experimental measurement results, it can be obtained that the gate groove obtained by the ICP etching technology that has not been improved by the design method is about one order of magnitude larger than the gate groove obtained by the ICP etching technology improved by the design method under the -30V gate bias, and is about 2-3 times larger than the gate groove leakage obtained by the improved method under the working voltage (-5V), and there is almost no difference in the gate groove performance of the two under the forward bias. The effectiveness of the etching control method of the groove structure for gate groove damage control is verified, thereby reducing the leakage current of the Schottky barrier part of the gate groove.
[0052] Furthermore, during the etching process of the groove-shaped structure, the etching power of the semiconductor etching device is controlled to gradually change according to a preset rule so that the groove-shaped structure obtained by etching meets the preset requirements, and the etching control method of the groove-shaped structure also includes:
[0053] The surface oxide and the cap layer of the semiconductor structure are removed by using a removal gas, wherein the semiconductor structure is a structure for preparing the gate trench structure.
[0054] Specifically, in semiconductor etching equipment, BCl is first used 3 Remove the surface oxide and cap layer. Then use BCl 3 +Cl 2 The barrier layer is etched. Based on this, the effectiveness of trench structure etching can be achieved.
[0055] In practice, when the slot-shaped structure is a gate trench structure and the semiconductor etching device is the inductively coupled plasma etching device, the initial source power of the semiconductor etching device is set to 120 W and the initial RF power is set to 5 W. It should be understood that when the slot-shaped structure is an isolation slot structure or a thin film grating structure, the initial source power and initial RF power of the semiconductor etching device can be reset.
[0056] During the etching process of the groove structure, controlling the etching power of the semiconductor etching device to gradually change according to a preset rule so that the groove structure obtained by etching meets the preset requirements includes:
[0057] During the etching process of the groove structure, the etching power of the semiconductor etching equipment is controlled to be linearly reduced to 3W within the etching time, so that the groove structure obtained by etching meets the preset requirements.
[0058] In practice, the RF power can be adjusted to gradually decrease to 3W during the etching time, wherein the etching time is 60s. Then the photoresist is removed and observed.
[0059] Based on the above description, in the etching process of the groove structure of the embodiment of the present invention, the etching power of the semiconductor etching equipment is controlled to be gradually reduced according to a preset rule to reduce the energy of the heavy groups of the plasma, thereby reducing damage to the channel, and the etching control method of the embodiment of the present invention, at the beginning of etching, uses a larger etching power to break the Ga-N bond of the material, therefore, the etching of the groove structure can be effectively completed, and at the same time, the damage to the deposition interface of the groove structure can be reduced, thereby improving the Schottky junction interface, making the interface smoother, and improving the roughness. The barrier height in the channel tends to be consistent and can effectively avoid and isolate the occurrence of leakage, while also avoiding the non-ideal Coulomb effect caused by defects and impurities.
[0060] In a second aspect, an embodiment of the present invention provides a groove-shaped structure, characterized in that the groove-shaped structure is obtained by etching according to the above-mentioned etching control method for the groove-shaped structure.
[0061] Since the embodiment of the present invention provides a groove-type structure that is obtained by etching based on the etching control method of the above-mentioned groove-type structure, the interface of the obtained groove-type structure is smoother, the roughness is improved, the barrier height in the channel tends to be consistent and can effectively avoid and isolate the occurrence of leakage, while also avoiding the non-ideal Coulomb effect caused by defects and impurities.
[0062] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art may understand and implement other variations of the disclosed embodiments by viewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple situations. A single processor or other unit may implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.
[0063] Although the present invention has been described in conjunction with specific features and embodiments thereof, it is apparent that various modifications and combinations may be made thereto without departing from the spirit and scope of the present invention. Accordingly, this specification and the accompanying drawings are merely exemplary illustrations of the present invention as defined by the appended claims and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the present invention. Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, the present invention is intended to include such modifications and variations if they fall within the scope of the claims of the present invention and their equivalents.
Claims
1. A method for controlling etching of a groove structure, characterized in that: Applied in semiconductor etching equipment, the etching control method of the groove structure comprises the following steps: Based on the groove structure to be etched, setting the initial etching power of the semiconductor etching device; wherein the groove structure to be etched is GaN material or / AlGaN material; During the etching process of the groove structure, the etching power of the semiconductor etching device is controlled to gradually decrease from the initial etching power according to a preset rule, so that the groove structure obtained by etching meets the preset requirements.
2. The etching control method of the groove structure according to claim 1, characterized in that: The initial etching power of the semiconductor etching equipment includes: an initial source power and an initial radio frequency power of the semiconductor etching equipment.
3. The etching control method of the groove structure according to claim 2, characterized in that: During the etching process of the groove structure, controlling the etching power of the semiconductor etching device to gradually change from the initial etching power according to a preset rule so that the etching obtained meets the preset requirements includes: During the etching process of the groove structure, the RF power of the semiconductor etching device is controlled to gradually decrease from the initial RF power, and the source power of the semiconductor etching device is controlled to remain unchanged, so that the etched structure meets the preset requirements.
4. The etching control method of the groove structure according to claim 2, characterized in that: During the etching process of the groove structure, controlling the etching power of the semiconductor etching device to gradually change according to a preset rule so that the groove structure obtained by etching meets the preset requirements includes: During the etching process of the groove structure, the RF power of the semiconductor etching equipment is controlled to gradually decrease from the initial RF power, and the source power of the semiconductor etching equipment is controlled to gradually decrease from the initial source power, so that the etched groove structure meets the preset requirements.
5. The etching control method of the groove structure according to any one of claims 1 to 4, characterized in that: The groove structure includes a gate trench structure, an isolation trench structure or a thin film grating structure.
6. The etching control method of the groove structure according to claim 5, characterized in that: The semiconductor etching equipment includes an inductively coupled plasma etching equipment, an electron cyclotron resonance plasma etching equipment or a reactive ion etching equipment.
7. The etching control method of the groove structure according to claim 6, characterized in that: During the etching process of the groove-shaped structure, the etching power of the semiconductor etching device is controlled to gradually change according to a preset rule so that the groove-shaped structure obtained by etching meets the preset requirements, and the etching control method of the groove-shaped structure further includes: The surface oxide and the cap layer of the semiconductor structure are removed by using a removal gas, wherein the semiconductor structure is a structure for preparing the gate trench structure.
8. The etching control method of the groove structure according to claim 7, characterized in that: When the groove structure is a gate trench structure and the semiconductor etching equipment is the inductively coupled plasma etching equipment, the initial source power of the semiconductor etching equipment is set to 120W and the initial radio frequency power is set to 5W.
9. The etching control method of the groove structure according to claim 8, characterized in that: During the etching process of the groove structure, controlling the etching power of the semiconductor etching device to gradually change according to a preset rule so that the groove structure obtained by etching meets the preset requirements includes: During the etching process of the groove structure, the etching power of the semiconductor etching equipment is controlled to be linearly reduced to 3W within the etching time, so that the groove structure obtained by etching meets the preset requirements.
10. A trough structure, characterized in that: The groove structure is obtained by etching according to the etching control method for a groove structure according to any one of claims 1 to 9.