Etching method of semiconductor device

Abstract

The invention relates to the technical field of manufacturing of semiconductor devices, in particular to an etching method of a semiconductor device, the semiconductor device is provided with a laminated structure, and the laminated structure comprises grooves and fin parts which are alternately arranged; metal oxide layers are deposited on the top end of the fin part, the side wall surface of the groove and the bottom wall surface of the groove; the etching method comprises the following steps: a first etching step: in a chlorine-based gas atmosphere, etching a metal oxide layer until the top end of a fin part is exposed, forming metal chloride and depositing the metal chloride in a groove; and a second etching step: in a hydrocarbon gas atmosphere, etching the metal chloride, and only depositing a carbon polymer at the top end of the fin part. According to the etching method of the semiconductor device provided by the invention, the chlorine-based gas and the hydrocarbon gas are adopted as reactants, etching of the metal oxide layer deposited in the semiconductor device is realized, the required etching time is short, and the etching rate is high.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor device manufacturing, and in particular to an etching method for a semiconductor device. Background Art

[0002] Thin-film transistors (TFTs) are important circuit switching control devices in the field of flat-panel display technology. The stability of the TFT's gate voltage is crucial to the display's brightness and operating life. 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 excellent 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. Aluminum oxide (Al2O3) offers excellent transmittance and insulation properties, is less susceptible to atmospheric reactions, and has a low production cost, making it an ideal metal oxide passivation layer material for TFTs.

[0003] For IGZO thin-film transistors, the etching of the indium gallium zinc oxide layer and the aluminum oxide layer is a key step. In related technologies, the etching of the aluminum oxide layer usually adopts the atomic layer etching (ALE) etching method. First, the semiconductor device is exposed to a fluorine-containing plasma gas atmosphere. The surface of the aluminum oxide (Al2O3) is isotropically fluorinated by the fluorine-containing plasma to modify the surface of the aluminum oxide, thereby forming aluminum fluoride (AlF3); then the semiconductor device is exposed to an atmosphere of trimethylaluminum (Al(CH3)3) to etch the aluminum fluoride (AlF3) to generate dimethylaluminum fluoride (AlF(CH3)2), which etches away the aluminum oxide (Al2O3) on the surface, thereby achieving isotropic etching of the aluminum oxide (Al2O3). However, this technical means has a low etching rate. Summary of the Invention

[0004] The present invention provides an etching method for a semiconductor device to solve the technical problem of low etching rate.

[0005] The present invention provides an etching method for a semiconductor device, wherein the semiconductor device has a stacked structure, wherein the stacked structure includes alternately arranged trenches and fins; a metal oxide layer is deposited on the top of the fin, the sidewalls of the trench, and the bottom wall of the trench; the etching method comprises the following steps:

[0006] The first etching step: etching the metal oxide layer in a chlorine-based gas atmosphere until the top of the fin is exposed, forming metal chloride and depositing it in the trench;

[0007] The second etching step: etching the metal chloride in a hydrocarbon gas atmosphere and depositing a carbon polymer on the top 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 surface of the trench and the metal chloride in the trench until the sidewall surface and the bottom wall surface of the trench are exposed.

[0009] Optionally, the process parameters of the first etching step and the second etching step both include an etching temperature, and 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 only deposited on the top of the fin.

[0011] Optionally, the first etching time is between 50-300 s; and the second etching time is between 10-100 s.

[0012] Optionally, the chlorine-based gas includes boron chloride and chlorine, the flow rate of the boron chloride is between 0-300 sccm, the flow rate of the chlorine is between 0-300 sccm; and the ratio between the flow rate of the boron chloride and the flow rate of the chlorine is between 1:3 and 3:1;

[0013] And / or, the hydrocarbon gas includes methane, and the flow rate of the methane is between 5-100 sccm.

[0014] Optionally, the process parameters of the first etching step further include an inert gas, and the flow rate of the inert gas is between 10-500 sccm;

[0015] And / or, the process parameters of the second etching step further include an inert gas, and the flow rate of the inert gas is between 10-500 sccm.

[0016] Optionally, the metal oxide layer includes a metal oxide conductive layer and a metal oxide insulating layer, and 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 the group consisting of indium, gallium, and zinc;

[0018] The material of the metal oxide insulating layer is an oxide of at least one metal selected from the group consisting of aluminum, chromium, zirconium, hafnium and titanium.

[0019] Optionally, the stacked structure includes a silicon layer and a silicon oxide layer sequentially arranged from bottom to top, and the trench and the fin are formed in the silicon oxide layer.

[0020] The etching method of a semiconductor device provided by the present invention has at least the following beneficial technical effects:

[0021] On the one hand, the process gas uses chlorine-based gas and hydrocarbon gas to achieve the etching of the metal oxide layer deposited in the semiconductor device, and the required etching time is short, that is, the etching rate is high;

[0022] On the other hand, chlorine-based gas is first used to react with the metal oxide layer to generate solid metal chloride, which is then deposited at the bottom of the trench. This can temporarily fill the trench and inhibit over-etching of the trench bottom in subsequent process steps, thereby improving the uniformity of the bottom end size of the trench. Hydrocarbon gas is then used to react with the metal chloride to generate volatile products that are discharged, thereby effectively removing the metal oxide.

[0023] In addition, the carbon polymer is deposited on the top of the fin, which inhibits damage to the fin in subsequent process steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic structural diagram of a semiconductor device before etching in a semiconductor etching method provided by an embodiment of the present invention;

[0025] Figure 2 A schematic diagram of a process flow of a semiconductor etching method provided by an embodiment of the present invention;

[0026] Figure 3 A schematic structural diagram of a semiconductor device after a first etching step in a semiconductor etching method provided by an embodiment of the present invention;

[0027] Figure 4 A schematic structural diagram of a semiconductor device after the second etching step in a semiconductor etching method provided by an embodiment of the present invention;

[0028] Figure 5 A schematic structural diagram of a semiconductor device after a first etching step and a second etching step are cycled in a semiconductor etching method provided by an embodiment of the present invention.

[0029] Description of reference numerals:

[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 DESCRIPTION

[0033] Related art discloses a method for etching aluminum oxide using an atomic layer etching method, comprising 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 an atmosphere of trimethylaluminum (Al(CH3)3) at a process temperature of 260°C. Trimethylaluminum (Al(CH3)3) reacts with aluminum fluoride (AlF3) to generate volatile dimethylaluminum fluoride (AlF(CH3)2), completing single-atomic layer etching.

[0036] It can be seen that in this related art, by using fluorine-containing plasma and trimethylaluminum (Al(CH3)3) as reactants, aluminum oxide is removed layer by layer. However, this related art has a low etching rate.

[0037] In order to improve the etching rate, an embodiment of the present invention provides an etching method for a semiconductor device, which uses chlorine-based gas and hydrocarbon gas as reactants to etch a metal oxide layer deposited in the semiconductor device, thereby improving the etching rate.

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the following Figure 1-Figure 5 The specific embodiments of the present invention are described in detail.

[0039] The embodiment of the present invention provides a method for etching a semiconductor device. Figure 1 The semiconductor device has a stacked structure, which includes alternately arranged trenches 105 and fins 103. For example, the material of the trenches 105 and the fins 103 can be silicon dioxide; a metal oxide layer is deposited on the top of the fin 103, the sidewall surface of the trench 105, and the bottom wall surface of the trench 105.

[0040] See attached Figure 2 、 Figure 3-Figure 4 The etching method is a plasma etching method, and the etching method includes the following steps:

[0041] S100, first etching step: in a chlorine-based gas atmosphere, etching the metal oxide layer until the top of the fin 103 is exposed, forming a 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 form 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: in a hydrocarbon gas atmosphere, etching the metal chloride 204 to form volatile products. For example, the hydrocarbon gas can be methane (CH4), and 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 depositing carbon polymer 301 on the top of the fin 103.

[0043] The etching method of a semiconductor device provided by an embodiment of the present invention, on the one hand, compared with the process gas using fluorine-containing plasma and trimethylaluminum (Al(CH3)3) in the related art to achieve atomic layer etching of the aluminum oxide layer of the semiconductor device, the process gas of the embodiment of the present invention uses chlorine-based gas and hydrocarbon gas to achieve plasma etching of the metal oxide layer deposited in the semiconductor device, and physical bombardment (ion sputtering) and chemical reaction (free radical etching) are carried out simultaneously, and the required etching time is short, that is, the etching rate is high; 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, which can temporarily fill the trench 105 and inhibit over-etching of the bottom of the trench 105 in subsequent process steps, thereby improving the uniformity of the bottom end size of the trench 105; then hydrocarbon gas is used to react with the metal chloride to generate volatile products for discharge, thereby achieving effective removal of the metal oxide; in addition, the carbon polymer 301 is deposited on the top of the fin 103, inhibiting damage to the fin 103 in subsequent process steps.

[0044] See attached Figure 4 and Figure 5In the embodiment of the present invention, the first etching step and the second etching step are cyclically performed at least once, for example, once, twice, or another number of times, to etch away the metal oxide layer remaining on the sidewalls of the trench 105 and the metal chloride 204 within the trench 105 until the sidewalls and bottom of the trench 105 are completely exposed. In this configuration, if the metal chloride 204 etched by the first etching step covers a portion of the metal oxide layer deposited on the sidewalls of the trench 105, the first etching step and the second etching step are cyclically performed to completely etch away the remaining metal oxide layer on the sidewalls of the trench 105.

[0045] In the embodiment of the present invention, taking the first etching step and the second etching step as an example, each of the first etching step and the second etching step is performed twice, and they are named in sequence: the first etching step, the first etching step, the second etching step, and the second etching step; specifically, as follows:

[0046] The first etching step: in a chlorine-based gas atmosphere, the metal oxide layer at the top of the fin 103 is etched until the top of the fin 103 is exposed, forming a metal chloride 204 which is deposited at the bottom of the trench 105; alternatively, the metal oxide layer at the top of the fin 103 and the bottom wall of the trench 105 is etched until the top of the fin 103 and the bottom wall of the trench 105 are exposed, forming a metal chloride 204 which is deposited 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 a carbon polymer 301 is deposited on the top of the fin 103 .

[0048] Second first etching step: In a chlorine-based gas atmosphere, the metal oxide layer remaining on the sidewall of the trench 105 is etched to form a metal chloride 204 which is deposited at the bottom of the trench 105 .

[0049] Second etching step: In a hydrocarbon gas atmosphere, the metal chloride 204 formed in the second etching step is etched until the sidewalls and bottom wall of the trench 105 are exposed, and a carbon polymer 301 is deposited on the top of the fin 103 .

[0050] In an embodiment of the present invention, the process parameters of the first etching step and the second etching step both include an etching temperature, and the etching temperature is greater than 40° C. and less than 100° C. For example, the metal oxide layer may be aluminum oxide (Al2O3) and indium gallium zinc oxide (IGZO). 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 greater 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 solid form. The trimethylaluminum (Al(CH3)3), trimethylindium (In(CH3)3), trimethylgallium (Ga(CH3)3), and dimethylzinc (Zn(CH3)2) formed in the second etching step have boiling points less than 150°C. Compared with the related art in which volatile products are generated by etching a metal oxide layer at high temperature, the embodiment of the present invention, on the one hand, converts the metal oxide into a solid metal chloride by limiting the etching temperature to less than or equal to 90°C, thereby facilitating the subsequent second etching step in converting the solid metal chloride into a volatile methyl metal; on the other hand, the low etching temperature eliminates the need for a high-temperature heating system, reducing energy consumption and equipment maintenance costs; in addition, a carbon polymer 301 is deposited on the top of the fin 103 to protect the silicon dioxide fin 103, thereby increasing the silicon dioxide / aluminum oxide selectivity.

[0051] In an embodiment of the present 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 only deposited 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. In this way, by limiting the ratio of the first etching time to the second etching time, during the process of hydrocarbon gas plasma etching of the solid metal chloride 204 generated in the first etching step, the carbon polymer 301 is only deposited on the top of the fin 103 and not on the metal oxide layer remaining on the side wall surface of the trench 105, thereby not hindering the subsequent process steps from etching the metal oxide remaining on the side wall surface of the trench 105.

[0052] In an embodiment of the present invention, the first etching time is between 50 and 300 seconds, and the second etching time is between 10 and 100 seconds. By limiting the first etching time to a certain range, etching of the silicon dioxide exposed at the top of the fin 103 is prevented. By limiting the second etching time to a certain range, the carbon polymer 301 is deposited only on the top of the fin 103 and not on the metal oxide layer remaining on the sidewalls of the trench 105, thereby preventing subsequent etching of the metal oxide remaining on the sidewalls of the trench 105.

[0053] In an embodiment of the present invention, the chlorine-based gas used in the first etching step includes boron chloride and chlorine, with chlorine serving as the main etching gas and boron chloride serving as the auxiliary gas. This provides boron chloride ions to bombard a metal oxide layer, such as aluminum oxide (Al2O3) and indium gallium zinc oxide (IGZO), thereby enhancing etching of the metal oxide layer. The boron chloride flow rate is between 0 and 300 sccm, and the chlorine flow rate is between 0 and 300 sccm. The ratio of the boron chloride flow rate to the chlorine flow rate is between 1:3 and 3:1.

[0054] In an embodiment of the present invention, the process parameters of the first etching step further include an inert gas, with a flow rate of the inert gas ranging from 10 to 500 sccm. The inert gas may be nitrogen, argon, or helium, which acts as a diluent gas to slow down the etching rate and prevent over-etching caused by an overreaction.

[0055] In an embodiment of the present invention, the hydrocarbon gas used in the second etching step includes methane (CH4), with a methane flow rate ranging from 5 to 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), which can trigger an etching reaction without requiring high temperatures. Methane (CH4) has low-temperature properties, 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)), 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)). These compounds are easily volatile, reducing contamination of the sidewalls and bottom walls of the trench 105 and improving etching uniformity. In addition, if the methyl radicals (CH 3 ) fail to combine with the metal chloride in time, carbon polymers may be formed and first deposited on the top of the fin 103 , thereby preventing damage to the fin 103 in subsequent process steps.

[0056] It should be noted that, in addition to methane, the hydrocarbon gas used in the second etching step may also be other hydrocarbon gases that can dissociate into CH3+ plasma, such as ethane.

[0057] In an embodiment of the present invention, the process parameters of the second etching step also include an inert gas. The inert gas flow rate 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, which can be nitrogen, argon, or helium, serves as a diluent gas to inhibit excessive decomposition of methane (CH4) to form carbon polymers, thereby preventing the carbon polymers from coating the metal oxide remaining on the sidewalls of the trench 105. This prevents the subsequent first etching step from etching the metal oxide remaining on the sidewalls.

[0058] In an embodiment of the present invention, the process parameters of the first etching step and the second etching step also include chamber pressure, upper electrode power, lower electrode power and chuck temperature, wherein the chamber pressure is between 10-80mT; the upper electrode power is between 600-2500W; the lower electrode power is between 0-1000W; and the chuck temperature is between 30-100°C.

[0059] See attached Figure 1 In the embodiment of the present invention, the metal oxide layer includes a metal oxide conductive layer 102 and a metal oxide insulating layer 101 , and the metal oxide insulating layer 101 is located outside the metal oxide conductive layer 102 .

[0060] In an embodiment of the present invention, the material of the metal oxide conductive layer 102 is an oxide of at least one metal selected from the group consisting of indium, gallium, and zinc; for example, the metal oxide conductive layer 102 may be at least one selected from the group consisting of indium gallium zinc oxide (IGZO), zinc oxide (ZnO), indium oxide (In2O3), and indium zinc oxide (IZO).

[0061] In an embodiment of the present invention, the material of the metal oxide insulating layer 101 is an oxide of at least one metal selected from the group consisting of aluminum, zirconium, titanium, hafnium, and lanthanum. For example, the material of the metal oxide 101 can be 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 attached Figure 4 In the embodiment of the present invention, 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 in the silicon oxide layer 106 .

[0063] In order to further illustrate the present invention, the etching method of the semiconductor device provided by the present invention is described in more detail below, but they should not be understood as limiting the scope of protection of the present invention.

[0064] In the embodiment of the present invention, see the attached 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 in sequence from bottom to top, and the silicon oxide layer 106 includes alternating trenches 105 and fins 103; the top of the fin 103, the sidewall surface of the trench 105 and the bottom wall surface of the trench 105 are sequentially deposited with a metal oxide conductive layer 102 and a metal oxide insulating layer 101, 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 of the semiconductor device provided by the embodiment of the present invention adopts step-by-step etching compared with the related art that uses fluorine-containing plasma and trimethylaluminum (Al(CH3)3) as reactants to achieve isotropic etching of aluminum oxide (Al2O3). 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, which can temporarily fill the trench 105 and inhibit over-etching of the bottom of the trench 105 in subsequent process steps, thereby improving the uniformity of the bottom end size 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, and the carbon polymer 301 is deposited only on the top of the fin 103, thereby inhibiting damage to the fin 103 in subsequent process steps. In addition, the embodiment of the present invention has a shorter etching time for the semiconductor device, thereby improving the etching rate or etching efficiency.

[0066] Finally, it should be noted that, in this document, terms such as "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements that are inherent to such process, method, article, or apparatus.

[0067] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to the embodiments will be readily apparent to one 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 present invention. Therefore, the present invention is not limited to the embodiments shown herein but is to be construed in the widest manner consistent with the principles and novel features disclosed herein.

Claims

1. A method for etching a semiconductor device, characterized in that: The semiconductor device has a stacked structure, the stacked structure comprising alternately arranged trenches (105) and fins (103); a metal oxide layer is deposited on the top of the fin (103), the sidewall surface of the trench (105), and the bottom wall surface of the trench (105); The etching method comprises the following steps: A first etching step: etching the metal oxide layer in a chlorine-based gas atmosphere until the top of the fin (103) is exposed, forming a metal chloride (204) and depositing it in the groove (105); The second etching step is to etch the metal chloride (204) in a hydrocarbon gas atmosphere and deposit a carbon polymer (301) on the top of the fin (103).

2. The etching method of a semiconductor device according to claim 1, wherein: The first etching step and the second etching step are cyclically performed to etch the metal oxide layer remaining on the sidewall surface of the trench (105) and the metal chloride (204) in the trench (105) until the sidewall surface of the trench (105) and the bottom wall surface of the trench (105) are exposed.

3. The etching method of a semiconductor device according to claim 1 or 2, characterized in that: The process parameters of the first etching step and the second etching step both include an etching temperature, and the etching temperature is greater than 40° C. and less than 100° C.

4. The etching method of a semiconductor device according to claim 1 or 2, 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 only deposited on the top of the fin (103).

5. The etching method of a semiconductor device according to claim 4, wherein: The first etching time is between 50-300 s; the second etching time is between 10-100 s.

6. The etching method of a semiconductor device according to claim 1 or 2, characterized in that: The chlorine-based gas includes boron chloride and chlorine, the flow rate of the boron chloride is between 0-300 sccm, the flow rate of the chlorine is between 0-300 sccm; the ratio between the flow rate of the boron chloride and the flow rate of the chlorine is between 1:3 and 3:1; And / or, the hydrocarbon gas includes methane, and the flow rate of the methane is between 5-100 sccm.

7. The etching method of a semiconductor device according to claim 1 or 2, characterized in that: The process parameters of the first etching step further include an inert gas, and the flow rate of the inert gas is between 10-500 sccm; And / or, the process parameters of the second etching step further include an inert gas, and the flow rate of the inert gas is between 10-500 sccm.

8. The etching method of a semiconductor device according to claim 1 or 2, characterized in that: The metal oxide layer comprises a metal oxide conductive layer (102) and a metal oxide insulating layer (101), wherein the metal oxide insulating layer (101) is located outside the metal oxide conductive layer (102).

9. The etching method of a semiconductor device according to claim 8, wherein: The material of the metal oxide conductive layer (102) is an oxide of at least one metal selected from the group consisting of indium, gallium, and zinc; The material of the metal oxide insulating layer (101) is an oxide of at least one metal selected from the group consisting of aluminum, chromium, zirconium, hafnium and titanium.

10. The etching method of a semiconductor device according to claim 1 or 2, characterized in that: The stacked structure comprises a silicon layer (104) and a silicon oxide layer (106) arranged in sequence from bottom to top, and the trench (105) and the fin (103) are formed in the silicon oxide layer (106).

Images