An etching method of a semiconductor device
By employing a stepwise etching method using chlorine-based and hydrocarbon gases, the problem of low etching rate of the alumina layer in IGZO thin-film transistors was solved, achieving a highly efficient etching process and improving etching uniformity and efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING INTEGRATED CIRCUIT EQUIPMENT INNOVATION CENTER CO LTD
- Filing Date
- 2025-06-17
- Publication Date
- 2026-05-22
Smart Images
Figure CN120749022B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor device manufacturing technology, and more specifically, to an etching method for semiconductor devices. Background Technology
[0002] Thin-film transistors (TFTs) are crucial circuit switching devices in flat panel display technology. The stability of the gate voltage of a TFT directly affects the display's brightness and lifespan. Indium gallium zinc oxide (IGZO) is used as the channel layer material in next-generation TFT technology due to its high mobility, low processing temperature, and good transparency to visible light. Depositing a metal oxide passivation layer on the IGZO TFT channel layer can effectively improve the device's gate voltage stability. Among these materials, aluminum oxide (Al2O3) has good transmittance and insulation properties, is not prone to reaction in the atmosphere, and has a low manufacturing cost, making it one of the ideal metal oxide passivation layer materials for TFTs.
[0003] For IGZO thin-film transistors, the etching of the indium gallium zinc oxide (IGZO) layer and the aluminum oxide (Al2O3) layer are critical steps. In related technologies, the etching of the aluminum oxide layer typically employs atomic layer etching (ALE). First, the semiconductor device is exposed to a fluorine-containing plasma atmosphere, isotropically fluorinating the surface of the aluminum oxide (Al2O3) to modify its surface and form aluminum fluoride (AlF3). Then, the semiconductor device is exposed to a trimethylaluminum (Al(CH3)3) atmosphere, etching the aluminum fluoride (AlF3) to generate dimethylaluminum fluoride (AlF(CH3)2), thus removing the surface aluminum oxide (Al2O3) and achieving isotropic etching of the aluminum oxide (Al2O3). However, this technique has a low etching rate. Summary of the Invention
[0004] This invention proposes an etching method for semiconductor devices to solve the technical problem of low etching rate.
[0005] This invention provides an etching method for a semiconductor device having a stacked structure, the stacked structure including alternating trenches and fins; a metal oxide layer is deposited on the top of the fins, the sidewalls of the trenches, and the bottom wall of the trenches; the etching method includes the following steps:
[0006] First etching step: In a chlorine-based gas atmosphere, the metal oxide layer is etched until the tip of the fin is exposed, forming a metal chloride and depositing it in the trench;
[0007] The second etching step involves etching the metal chloride in a hydrocarbon gas atmosphere and depositing a carbon polymer at the tip of the fin.
[0008] Optionally, the first etching step and the second etching step are performed cyclically to etch the metal oxide layer remaining on the sidewall of the trench and the metal chloride in the trench until the sidewall of the trench and the bottom wall of the trench are exposed.
[0009] Optionally, the process parameters for both the first etching step and the second etching step include etching temperature, wherein the etching temperature is greater than 40°C and less than 100°C.
[0010] Optionally, the process parameters of the first etching step include a first etching time, and the process parameters of the second etching step include a second etching time; the ratio of the first etching time to the second etching time is between 30:1 and 10:1, so that the carbon polymer is deposited only on the top of the fin.
[0011] Optionally, the first etching time is between 50 and 300 seconds; the second etching time is between 10 and 100 seconds.
[0012] Optionally, the chlorine-based gas includes boron chloride and chlorine, wherein the flow rate of boron chloride is between 0 and 300 sccm, and the flow rate of chlorine is between 0 and 300 sccm; the ratio between the flow rate of boron chloride and the flow rate of chlorine is between 1:3 and 3:1.
[0013] And / or, the hydrocarbon gas includes methane, the flow rate of which is between 5 and 100 sccm.
[0014] Optionally, the process parameters of the first etching step further include an inert gas, the flow rate of which is between 10-500 sccm;
[0015] And / or, the process parameters of the second etching step also include an inert gas, the flow rate of which is between 10-500 sccm.
[0016] Optionally, the metal oxide layer includes a metal oxide conductive layer and a metal oxide insulating layer, wherein the metal oxide insulating layer is located outside the metal oxide conductive layer.
[0017] Optionally, the metal oxide conductive layer is made of an oxide of at least one metal selected from indium, gallium, and zinc;
[0018] The metal oxide insulating layer is made of an oxide of at least one of the following metals: aluminum, chromium, zirconium, hafnium, and titanium.
[0019] Optionally, the stacked structure includes a silicon layer and a silicon oxide layer disposed sequentially from bottom to top, and the trench and the fin are formed in the silicon oxide layer.
[0020] The etching method for semiconductor devices provided by this invention has at least the following beneficial technical effects:
[0021] On the one hand, the process gases use chlorine-based gases and hydrocarbon gases to etch the metal oxide layers deposited in semiconductor devices, requiring a short etching time, i.e., a high etching rate;
[0022] On the other hand, chlorine-based gas is first used to react with the metal oxide layer to generate solid metal chlorides, which are deposited at the bottom of the trench. This can temporarily fill the trench and suppress over-etching of the bottom of the trench in subsequent process steps, thereby improving the uniformity of the bottom dimensions of the trench. Then, hydrocarbon gas is used to react with the metal chlorides to generate volatile products, which are discharged, thereby achieving effective removal of metal oxides.
[0023] In addition, carbon polymer is deposited on the tip of the fin, which inhibits damage to the fin in subsequent process steps. Attached Figure Description
[0024] Figure 1 A schematic diagram of the structure of a semiconductor device before etching, provided in an embodiment of the present invention;
[0025] Figure 2 A schematic diagram of the process flow of a semiconductor etching method provided in an embodiment of the present invention;
[0026] Figure 3 This is a schematic diagram of the structure of a semiconductor device after the first etching step in a semiconductor etching method provided in an embodiment of the present invention;
[0027] Figure 4 This is a schematic diagram of the structure of a semiconductor device after the second etching step in a semiconductor etching method provided in an embodiment of the present invention;
[0028] Figure 5 This is a schematic diagram of the structure of a semiconductor device after cyclic etching steps one and two, provided in an embodiment of the present invention.
[0029] Explanation of reference numerals in the attached figures:
[0030] 101. Metal oxide insulating layer; 102. Metal oxide conductive layer; 103. Fin;
[0031] 104, silicon layer; 105, trench; 106, silicon oxide layer; 204, metal chloride;
[0032] 301. Carbon polymer. Detailed Implementation
[0033] The related technology discloses an etching method for aluminum oxide using atomic layer etching, including the following steps:
[0034] Fluorination stage: The semiconductor device is exposed to a fluorine-containing plasma gas atmosphere at a process temperature of 260°C. Fluorine radicals or ions react with the surface of aluminum oxide (Al2O3) to form aluminum fluoride (AlF3), thereby modifying the surface of aluminum oxide (Al2O3).
[0035] Ligand exchange stage: The semiconductor device is exposed to a trimethylaluminum (Al(CH3)3) atmosphere at a process temperature of 260°C. Trimethylaluminum (Al(CH3)3) reacts with aluminum fluoride (AlF3) to generate volatile dimethylaluminum fluoride (AlF(CH3)2), thus completing the single-atom layer etching.
[0036] Therefore, this related technology achieves layer-by-layer removal of alumina by using fluorine-containing plasma and trimethylaluminum (Al(CH3)3) as reactants. However, the etching rate of this related technology is low.
[0037] To improve the etching rate, this invention provides an etching method for semiconductor devices. By using chlorine-based gas and hydrocarbon gas as reactants, the etching of the metal oxide layer deposited in the semiconductor device is achieved, thereby improving the etching rate.
[0038] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the following description is provided in conjunction with the accompanying drawings. Figures 1-5 Specific embodiments of the present invention will be described in detail below.
[0039] This invention provides an etching method for semiconductor devices, see attached figure. Figure 1 The semiconductor device has a stacked structure, which includes alternating trenches 105 and fins 103. For example, the trenches 105 and fins 103 can be made of silicon dioxide. A metal oxide layer is deposited on the top of the fins 103, the sidewalls of the trenches 105 and the bottom wall of the trenches 105.
[0040] See appendix Figure 2 , Figures 3-4 The etching method is a plasma etching method, which includes the following steps:
[0041] S100, First etching step: Under a chlorine-based gas atmosphere, the metal oxide layer is etched until the top of the fin 103 is exposed, forming metal chloride 204 and depositing it in the trench 105; for example, the chlorine-based gas can be chlorine (Cl2), and the metal oxide layer can be aluminum oxide (Al2O3) and indium gallium zinc oxide (IGZO). Chlorine (Cl2) reacts with aluminum oxide (Al2O3) and indium gallium zinc oxide (IGZO) to generate solid aluminum chloride (AlCl3), indium chloride (InCl3), gallium chloride (GaCl3) and zinc chloride (ZnCl2), which are then deposited in the trench 105;
[0042] S110, Second etching step: Under a hydrocarbon gas atmosphere, metal chloride 204 is etched to form volatile products. For example, the hydrocarbon gas can be methane (CH4). Methane (CH4) reacts with solid aluminum chloride (AlCl3), indium chloride (InCl3), gallium chloride (GaCl3) and zinc chloride (ZnCl2) to generate volatile trimethylaluminum (Al(CH3)3), trimethylindium (In(CH3)3), trimethylgallium (Ga(CH3)3) and dimethylzinc (Zn(CH3)2); and carbon polymer 301 is deposited on the top of fin 103.
[0043] The etching method for semiconductor devices provided in this embodiment of the invention, on the one hand, compared with the related technology that uses fluorine-containing plasma and trimethylaluminum (Al(CH3)3) as process gas to achieve atomic layer etching of the alumina layer of the semiconductor device, the process gas of this embodiment of the invention uses chlorine-based gas and hydrocarbon gas to achieve plasma etching of the metal oxide layer deposited in the semiconductor device. Physical bombardment (ion sputtering) and chemical reaction (free radical etching) are carried out simultaneously, requiring a short etching time, i.e., a high etching rate. On the other hand, chlorine-based gas is first used to react with the metal oxide layer to generate solid metal chloride, which is deposited at the bottom of the trench 105. This can temporarily fill the trench 105 and suppress over-etching of the bottom of the trench 105 in subsequent process steps, thereby improving the uniformity of the bottom dimension of the trench 105. Then, hydrocarbon gas is used to react with the metal chloride to generate volatile products that are discharged, thereby achieving effective removal of the metal oxide. In addition, carbon polymer 301 is deposited on the top of the fin 103 to suppress damage to the fin 103 in subsequent process steps.
[0044] See appendix Figure 4 and Figure 5In this embodiment of the invention, the first etching step and the second etching step are performed cyclically, at least once, for example, once, twice, or other times, to etch the residual metal oxide layer on the sidewall of the trench 105 and the metal chloride 204 within the trench 105 until the sidewall and bottom wall of the trench 105 are completely exposed. With this configuration, if the metal chloride 204 obtained by the first etching step covers part of the metal oxide layer deposited on the sidewall of the trench 105, the first and second etching steps are performed cyclically to completely etch away the residual metal oxide layer on the sidewall of the trench 105.
[0045] In this embodiment of the invention, taking the example of performing both the first etching step and the second etching step twice, they are named sequentially as: first first etching step, first second etching step, second first etching step, and second first etching step; specifically as follows:
[0046] First etching step: In a chlorine-based gas atmosphere, etch the metal oxide layer at the top of the fin 103 until the top of the fin 103 is exposed, forming metal chloride 204 and depositing it at the bottom of the trench 105; or, etch the metal oxide layer at the top of the fin 103 and the bottom wall of the trench 105 until the top of the fin 103 and the bottom wall of the trench 105 are exposed, forming metal chloride 204 and depositing it at the bottom of the trench 105.
[0047] First second etching step: In a hydrocarbon gas atmosphere, the metal chloride 204 formed in the first etching step is etched until the metal oxide layer remaining on the sidewall of the trench 105 is exposed, and carbon polymer 301 is deposited on the top of the fin 103.
[0048] Secondary first etching step: Under a chlorine-based gas atmosphere, the residual metal oxide layer on the sidewall of trench 105 is etched to form metal chloride 204 and deposited at the bottom of trench 105.
[0049] Secondary etching step: Under a hydrocarbon gas atmosphere, the metal chloride 204 formed in the secondary etching step is etched until the sidewalls and bottomwalls of the trench 105 are exposed, and carbon polymer 301 is deposited on the top of the fin 103.
[0050] In this embodiment of the invention, the process parameters for both the first and second etching steps include etching temperature, which is greater than 40°C and less than 100°C. For example, the metal oxide layer can be aluminum oxide (Al2O3) and indium gallium zinc oxide (IGZO). In this case, the first etching step forms aluminum chloride (AlCl3), indium chloride (InCl3), gallium chloride (GaCl3), and zinc chloride (ZnCl2). The sublimation temperatures of aluminum chloride (AlCl3), indium chloride (InCl3), gallium chloride (GaCl3), and zinc chloride (ZnCl2) are all higher than 150°C. When the etching temperature of the first etching step is less than or equal to 90°C, aluminum chloride (AlCl3), indium chloride (InCl3), gallium chloride (GaCl3), and zinc chloride (ZnCl2) are in a solid state. The second etching step produces trimethylaluminum (Al(CH3)3), trimethylindium (In(CH3)3), trimethylgallium (Ga(CH3)3), and dimethylzinc (Zn(CH3)2), all of which have boiling points below 150°C. Compared to related technologies where etching metal oxide layers at high temperatures generates volatile products, this embodiment of the invention, by limiting the etching temperature to less than or equal to 90°C, converts the metal oxide into solid metal chlorides, facilitating the subsequent conversion of the solid metal chlorides into volatile methyl metals in the second etching step. Furthermore, the low etching temperature eliminates the need for a high-temperature heating system, reducing energy consumption and equipment maintenance costs. Additionally, the deposition of carbon polymer 301 at the top of the fin 103 protects the silicon dioxide fin 103, allowing for a high silicon dioxide / alumina selectivity ratio.
[0051] In this embodiment of the invention, the process parameters of the first etching step include a first etching time, and the process parameters of the second etching step include a second etching time. The ratio of the first etching time to the second etching time is between 30:1 and 10:1, so that the carbon polymer 301 is deposited only on the top of the fin 103. Preferably, the ratio of the first etching time to the second etching time is between 25:1 and 15:1. More preferably, the ratio of the first etching time to the second etching time is between 20:1 and 5:1. By limiting the ratio of the first etching time to the second etching time, during the etching of the solid metal chloride 204 generated in the first etching step by hydrocarbon gas plasma, the carbon polymer 301 is deposited only on the top of the fin 103 and not on the residual metal oxide layer on the sidewall of the trench 105, thereby not hindering the subsequent process steps from etching the residual metal oxide on the sidewall of the trench 105.
[0052] In this embodiment of the invention, the first etching time is between 50-300 s; the second etching time is between 10-100 s. This configuration, by limiting the first etching time within a certain range, prevents the silicon dioxide exposed at the tip of the fin 103 from being etched; and by limiting the second etching time within a certain range, ensures that the carbon polymer 301 is deposited only at the tip of the fin 103 and not on the residual metal oxide layer on the sidewall of the trench 105, thus not hindering subsequent process steps from etching the residual metal oxide on the sidewall of the trench 105.
[0053] In this embodiment of the invention, the chlorine-based gas in the first etching step includes boron chloride and chlorine gas, wherein chlorine gas serves as the main etching gas and boron chloride serves as the auxiliary gas, providing boron chloride ion bombardment of the metal oxide layer. For example, the metal oxide layer can be aluminum oxide (Al2O3) and indium gallium zinc oxide (IGZO) to enhance the etching of the metal oxide layer. The flow rate of boron chloride is between 0 and 300 sccm, and the flow rate of chlorine gas is between 0 and 300 sccm; the ratio of the flow rate of boron chloride to the flow rate of chlorine gas is between 1:3 and 3:1.
[0054] In this embodiment of the invention, the process parameters of the first etching step also include an inert gas, the flow rate of which is between 10-500 sccm. The inert gas can be nitrogen, argon, or helium, used as a dilution gas to slow down the etching rate and prevent excessive etching due to over-reaction.
[0055] In this embodiment of the invention, the hydrocarbon gas in the second etching step includes methane (CH4), with a flow rate between 5-100 sccm. It should be noted that methane (CH4) can be activated in a low-temperature plasma environment to generate highly reactive methyl radicals (CH3) and hydrogen radicals (H), initiating the etching reaction without high temperatures. Methane (CH4) has low-temperature characteristics, which can prevent lattice damage to semiconductor devices caused by thermal stress. When methane (CH4) reacts with metal chlorides (e.g., aluminum chloride (AlCl3), indium chloride (InCl3), gallium chloride (GaCl3), and zinc chloride (ZnCl2)), the methyl radicals replace chlorine atoms to generate volatile compounds (e.g., trimethylaluminum (Al(CH3)3), trimethylindium (In(CH3)3), trimethylgallium (Ga(CH3)3), and dimethylzinc (Zn(CH3)2)), which are easily volatilized, reducing contamination of the sidewalls and bottom walls of trench 105 and improving etching uniformity. In addition, if the methyl radical (CH3) does not combine with the metal chloride in time, a carbon polymer can be formed and deposited first on the top of the fin 103, inhibiting damage to the fin 103 in subsequent process steps.
[0056] It should be noted that the hydrocarbon gas in the second etching step can be other hydrocarbon gases that can dissociate into CH3+ plasma, such as ethane, in addition to methane.
[0057] In this embodiment of the invention, the process parameters of the second etching step further include an inert gas. The flow rate of the inert gas is between 10 and 500 sccm, and the ratio of the inert gas flow rate to the methane flow rate is between 10:1 and 2:1. The inert gas can be nitrogen, argon, or helium, used as a dilution gas to inhibit the excessive decomposition of methane (CH4) to generate carbon polymers, preventing carbon polymers from covering the residual metal oxides on the sidewalls of trench 105, thus not hindering the subsequent etching of the residual metal oxides on the sidewalls in the first etching step.
[0058] In this embodiment of the invention, the process parameters for the first etching step and the second etching step further include chamber pressure, upper electrode power, lower electrode power and chuck temperature, wherein the chamber pressure is between 10-80 mT; the upper electrode power is between 600-2500 W; the lower electrode power is between 0-1000 W; and the chuck temperature is between 30-100°C.
[0059] See appendix Figure 1 In this embodiment of the invention, the metal oxide layer includes a metal oxide conductive layer 102 and a metal oxide insulating layer 101, with the metal oxide insulating layer 101 located outside the metal oxide conductive layer 102.
[0060] In this embodiment of the invention, the metal oxide conductive layer 102 is made of an oxide of at least one of indium, gallium, and zinc; for example, the metal oxide conductive layer 102 can be at least one of indium gallium zinc oxide (IGZO), zinc oxide (ZnO), indium oxide (In2O3), or indium zinc oxide (IZO).
[0061] In this embodiment of the invention, the metal oxide insulating layer 101 is made of an oxide of at least one metal selected from aluminum, zirconium, titanium, hafnium, and lanthanum. For example, the metal oxide 101 can be made of at least one of aluminum oxide (Al2O3), zirconium oxide (ZrO2), titanium oxide (TiO2), hafnium oxide (HfO2), lanthanum oxide (LaO), hafnium zirconium oxide (HfZrO), hafnium aluminum oxide (HfAlO), and hafnium titanium oxide (HfTiO).
[0062] See appendix Figure 4 In this embodiment of the invention, the stacked structure includes a silicon layer 104 and a silicon oxide layer 106 arranged sequentially from bottom to top, and trenches 105 and fins 103 are formed on the silicon oxide layer 106.
[0063] To further illustrate the present invention, the etching method for semiconductor devices provided by the present invention will be described in more detail below, but it should not be construed as a limitation on the scope of protection of the present invention.
[0064] In this embodiment of the invention, see appendix. Figure 1 and Figure 4 The semiconductor device has a stacked structure, which includes a silicon layer 104 and a silicon oxide layer 106 arranged sequentially from bottom to top. The silicon oxide layer 106 includes alternating trenches 105 and fins 103. A metal oxide conductive layer 102 and a metal oxide insulating layer 101 are deposited sequentially on the top of the fins 103, the sidewalls of the trenches 105 and the bottom wall of the trenches 105, wherein the metal oxide conductive layer 102 is an indium gallium zinc oxide layer (IGZO) and the metal oxide insulating layer 101 is an aluminum oxide layer (Al2O3).
[0065] In summary, the etching method for semiconductor devices provided in this embodiment of the invention, compared with the related technology that uses fluorine-containing plasma and trimethylaluminum (Al(CH3)3) as reactants to achieve isotropic etching of aluminum oxide (Al2O3), adopts a step-by-step etching method. Specifically, in an atmosphere of boron chloride, chlorine, and inert gas, the indium gallium zinc oxide layer and the aluminum oxide layer are etched to form solid aluminum chloride, indium chloride, gallium chloride, and zinc chloride, which are deposited at the bottom of the trench 105. This can temporarily fill the trench 105 and suppress over-etching of the bottom of the trench 105 in subsequent process steps, thereby improving the uniformity of the bottom dimension of the trench 105. Then, in an atmosphere of methane and inert gas, the solid aluminum chloride, indium chloride, gallium chloride, and zinc chloride are etched to form volatile trimethylaluminum, trimethylindium, trimethylgallium, and dimethylzinc. Carbon polymer 301 is deposited only at the top of the fin 103, thereby suppressing damage to the fin 103 in subsequent process steps. Furthermore, the etching time for the aforementioned semiconductor devices is shorter in the embodiments of the present invention, thereby improving the etching rate or etching efficiency.
[0066] Finally, it should be noted that, in this document, terms such as “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0067] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to the embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. An etching method for a semiconductor device, characterized in that, The semiconductor device has a stacked structure, the stacked structure including alternating trenches (105) and fins (103); the top of the fins (103), the sidewalls of the trenches (105) and the bottom wall of the trenches (105) are deposited with metal oxide layers; The etching method includes the following steps: First etching step: In a chlorine-based gas atmosphere, the metal oxide layer is etched until the top of the fin (103) is exposed, forming a metal chloride (204) and depositing it in the trench (105); Second etching step: In a hydrocarbon gas atmosphere, the metal chloride (204) is etched and a carbon polymer (301) is deposited on the top of the fin (103). The first etching step and the second etching step are repeated to etch the metal oxide layer remaining on the sidewall of the trench (105) and the metal chloride (204) in the trench (105) until the sidewall of the trench (105) and the bottom wall of the trench (105) are exposed.
2. The etching method for a semiconductor device according to claim 1, characterized in that, The process parameters for both the first etching step and the second etching step include etching temperature, which is greater than 40°C and less than 100°C.
3. The etching method for a semiconductor device according to claim 1, characterized in that, The process parameters of the first etching step include a first etching time, and the process parameters of the second etching step include a second etching time; the ratio of the first etching time to the second etching time is between 30:1 and 10:1, so that the carbon polymer (301) is deposited only on the top of the fin (103).
4. The etching method for a semiconductor device according to claim 3, characterized in that, The first etching time is between 50 and 300 seconds; the second etching time is between 10 and 100 seconds.
5. The etching method for a semiconductor device according to claim 1, characterized in that, The chlorine-based gas includes boron chloride and chlorine gas, the flow rate of boron chloride is between 0 and 300 sccm, and the flow rate of chlorine gas is between 0 and 300 sccm; the ratio between the flow rate of boron chloride and the flow rate of chlorine gas is between 1:3 and 3:
1. And / or, the hydrocarbon gas includes methane, the flow rate of which is between 5 and 100 sccm.
6. The etching method for a semiconductor device according to claim 1, characterized in that, The process parameters for the first etching step also include an inert gas, the flow rate of which is between 10-500 sccm; And / or, the process parameters of the second etching step also include an inert gas, the flow rate of which is between 10-500 sccm.
7. The etching method for a semiconductor device according to claim 1, characterized in that, The metal oxide layer includes a metal oxide conductive layer (102) and a metal oxide insulating layer (101), with the metal oxide insulating layer (101) located outside the metal oxide conductive layer (102).
8. The etching method for a semiconductor device according to claim 7, characterized in that, The metal oxide conductive layer (102) is made of an oxide of at least one of the metals selected from indium, gallium, and zinc. The metal oxide insulating layer (101) is made of an oxide of at least one of the following metals: aluminum, chromium, zirconium, hafnium, and titanium.
9. The etching method for a semiconductor device according to claim 1, characterized in that, The stacked structure includes a silicon layer (104) and a silicon oxide layer (106) arranged sequentially from bottom to top, and the trench (105) and the fin (103) are formed on the silicon oxide layer (106).