Etching apparatus and method of maintenance thereof

Abstract

An etching device and a method for maintaining the same, the etching device comprising a wafer susceptor, a coupled upper electrode plate, and an upper cooling plate for cooling the upper electrode plate; the method comprising: performing at least one round of processing on the upper cooling plate to form a protective layer on a part of the surface of the upper cooling plate, the part of the surface of the upper cooling plate at least including a first surface facing the wafer susceptor; wherein each round of processing comprises: performing bombardment processing on the part of the surface of the upper cooling plate; and using a first reaction gas to form at least a part of the protective layer on the surface of the upper cooling plate after bombardment. The present application can improve the service life of the upper cooling plate and reduce the replacement cost.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to an etching apparatus and its maintenance method. Background Technology

[0002] With the development of semiconductor technology, dry etching equipment with plasma etching chambers has been widely used. When gas exists in plasma form, its chemical activity is much stronger than under normal conditions. Depending on the material being etched, selecting a suitable gas can enable faster reaction with the material, achieving etching. In addition, an electric field can be used to guide and accelerate the plasma, giving it a certain energy. When the plasma bombards the surface of the object being etched, it ejects atoms of the material, thus achieving the purpose of etching through physical energy transfer.

[0003] Existing etching equipment typically includes an upper electrode and a lower electrode, for example, formed using a plate-like morphology. Specifically, the upper and lower electrodes can be mounted parallel to each other on the upper and lower sides of a wafer substrate. By creating an electric field between the two electrodes sufficient to convert the reactive gas into a plasma gas state, and by injecting a predetermined reactive gas between the upper and lower electrodes, a predetermined area of ​​the wafer is etched using plasma gas. During this process, the electrode plates can be cooled using a cooling plate, for example, an upper cooling plate can be used to cool the upper electrode plate to control the temperature of the upper electrode.

[0004] However, in an existing cooling plate, the first surface facing the wafer substrate is prone to surface cracking. In severe cases, the cracked fragments fall onto the wafer surface, resulting in particle defects.

[0005] There is an urgent need for a maintenance method for etching equipment that can treat the surface of the upper cooling plate in the etching equipment to reduce the possibility of surface cracking on the first side of the upper cooling plate facing the wafer substrate. Summary of the Invention

[0006] The technical problem solved by this invention is to provide an etching device and its maintenance method, which can improve the service life of the upper cooling plate and reduce replacement costs.

[0007] To solve the above technical problems, the embodiment of the present application provides a maintenance method of an etching device, the etching device comprising a wafer base, a coupled upper electrode plate, and an upper cooling plate for cooling the upper electrode plate; the method comprising: performing at least one round of processing process on the upper cooling plate to form a protective layer on a part of the surface of the upper cooling plate, the part of the surface of the upper cooling plate at least comprising a first surface facing the wafer base; wherein each round of processing process comprises: performing bombardment treatment on the part of the surface of the upper cooling plate; and using a first reaction gas to form at least a part of the protective layer on the surface of the upper cooling plate after bombardment.

[0008] Optionally, the method comprises one or more of the following: the material of the first surface of the upper cooling plate facing the wafer base is aluminum oxide; the first reaction gas comprises C x F y : the material of the protective layer comprises AlF3; and the chemical reaction formula for forming at least a part of the protective layer on the surface of the upper cooling plate after bombardment using the first reaction gas is:

[0009] Al2O3+ C x F y AlF3 (s) +CO2 (g)。

[0010] Optionally, the value of y is greater than the value of x.

[0011] Optionally, the first reaction gas C x F y is one or a combination of the following: CF4, CF3, and CF2.

[0012] Optionally, each round of processing process further comprises: using a second reaction gas to remove a by-product; wherein the by-product is formed in the process of forming at least a part of the protective layer on the part of the surface of the upper cooling plate using the first reaction gas.

[0013] Optionally, the material of the part of the surface of the upper cooling plate comprises aluminum oxide, and the first reaction gas comprises C x F y ; the method comprises one or more of the following: the by-product comprises C x , and the C x is attached to the protective layer; the second reaction gas comprises O2; and the chemical reaction formula is:

[0014] C x + O2 CO2 (g)。

[0015] Optionally, the process for removing the byproduct reaction product by using the second reaction gas comprises a first reaction stage and a second reaction stage; wherein the chamber pressure of the first reaction stage is greater than the chamber pressure of the first reaction stage.

[0016] Optionally, the process time of the first reaction stage is less than or equal to the waiting time for the second reaction gas to react with the material of the protective layer.

[0017] Optionally, the method comprises one or more of the following: the chamber pressure of the first reaction stage is selected from 180mT to 220mT; the process time of the first reaction stage is selected from 10s to 30s; the chamber pressure of the second reaction stage is selected from 30mT to 50mT; the process time of the second reaction stage is selected from 10s to 15s.

[0018] Optionally, the second reaction gas is O2, and the process parameters of the process for removing the byproduct reaction product by using O2 further comprise one or more of the following: the gas flow of the O2 is selected from 1000sccm to 1400sccm; the high-frequency RF power is selected from 1300W to 1700W; the low-frequency RF power is selected from 800W to 1200W.

[0019] Optionally, the method further comprises: providing one or more wafers; placing a single wafer into the etching chamber before each round of process on the upper cooling plate, and removing the wafer from the etching chamber after each round of removing the byproduct reaction product.

[0020] Optionally, the number of wafers is multiple; wherein in each round of process, the multiple wafers are placed in the etching chamber according to a preset cycle sequence.

[0021] Optionally, the wafer is a bare wafer without a dielectric layer on the surface.

[0022] Optionally, the upper cooling plate comprises stacked aluminum oxide plates and aluminum material plates from bottom to top, and is placed on the upper electrode plate, and has a non-zero gap between the aluminum oxide plate and the upper electrode plate, wherein a plurality of gas supply holes for supplying gas pass through the stacked aluminum material plates, aluminum oxide plates and upper electrode plates; the bombardment process on part of the surface of the upper cooling plate comprises: bombarding the sidewall of the gas supply hole and the side surface of the aluminum oxide plate facing the upper electrode plate; forming at least part of the protective layer on the surface of the upper cooling plate after bombardment comprises: forming at least part of the protective layer on the sidewall of the gas supply hole and the side surface of the aluminum oxide plate facing the upper electrode plate.

[0023] Optionally, the gas used for the bombardment process comprises argon, and the plasma used for the bombardment process comprises argon plasma.

[0024] Optionally, the process parameters for the bombardment process using argon plasma include one or more of the following: the gas flow of the argon is selected from 700sccm to 800sccm; the process time is selected from 100s to 140s; the chamber pressure is selected from 20mT to 30mT; the high frequency RF power is selected from 3100W to 3500W; and the low frequency RF power is selected from 3600W to 4000W.

[0025] Optionally, the first reaction gas comprises CF4, and the process parameters for forming at least a portion of the protective layer on the surface of the upper cooling plate after bombardment using the CF4include one or more of the following: the gas flow of the CF4is selected from 80sccm to 120sccm; the process time is selected from 100s to 140s; the chamber pressure is selected from 60mT to 100mT; the high frequency RF power is selected from 1200W to 1800W; and the low frequency RF power is selected from 400W to 600W.

[0026] Optionally, the first reaction gas further comprises argon, and the gas flow of the argon is selected from 250sccm to 350sccm.

[0027] Optionally, the total process time of the at least one process for the upper cooling plate is greater than or equal to a first time, and / or the total number of rounds of the at least one process for the upper cooling plate is greater than or equal to a first number of rounds.

[0028] Optionally, the first number of rounds is selected from 100 rounds to 300 rounds, and / or the first time is selected from 5hrs to 15hrs.

[0029] To solve the above technical problems, an embodiment of the present application provides an etching device, which comprises a wafer base, a coupled upper electrode plate, and an upper cooling plate for cooling the upper electrode plate; wherein a portion of the surface of the upper cooling plate is formed with a protective layer, and the portion of the surface of the upper cooling plate at least comprises a first surface facing the wafer base; the protective layer is formed through at least one process, and each process comprises, after bombardment of the portion of the surface of the upper cooling plate, forming at least a portion of the protective layer on the surface of the upper cooling plate after bombardment using a first reaction gas.

[0030] Optionally, the material of the portion of the surface of the upper cooling plate comprises alumina, and / or the material of the protective layer comprises AlF3.

[0031] Compared with the prior art, the technical scheme of the embodiment of the present application has the following beneficial effects:

[0032] In the embodiment of the present application, by setting one or more rounds of processing processes, and performing bombardment treatment on part of the surface of the upper cooling plate in each round of processing process; then using the first reaction gas to form at least part of the protective layer on the surface of the upper cooling plate after bombardment, the protective layer can be formed on part of the surface of the upper cooling plate, the surface of the upper cooling plate facing the wafer pedestal is effectively protected, the possibility of surface cracking of the first surface of the upper cooling plate facing the wafer pedestal is reduced, thereby reducing the problem of particle defects and improving device quality. In addition, by first performing bombardment treatment on part of the surface of the upper cooling plate and then forming a protective layer, compared with directly forming a protective layer, the roughness of part of the surface of the upper cooling plate can be increased by bombardment, and the protective layer formed on this basis can have higher adhesion, thereby helping to improve the service life of the upper cooling plate and reduce replacement costs. In addition, by forming through multiple rounds of processing processes, the density of the formed protective layer can be improved, and the adhesion between the protective layers formed in each round can be increased, further improving the service life of the upper cooling plate.

[0033] Further, for the case that the material of the first surface of the upper cooling plate facing the wafer pedestal is aluminum oxide, the problem of particle defects is particularly prone to occur after cracking, which can be solved by using the first reaction gas to include C x F y , the material of the protective layer includes AlF3, and solid AlF3 is formed to protect the surface of the aluminum oxide material and reduce the possibility of cracking.

[0034] Further, the first reaction gas includes C x F y , and the value of y is greater than the value of x. Since the F element accounts for a large proportion, after being dissociated into plasma, the concentration of F plasma is greater, and it is less likely to occur reverse reaction and more likely to react with Al ions. Compared with the reaction gas with a small proportion of F element, which leads to serious reverse reaction and weak reaction with Al ions, the present application can enhance the forward reaction and better form solid AlF3 as the protective layer.

[0035] Further, since by-products are formed during the formation of the protective layer, such as long carbon chain polymer complexes (also known as C polymers) formed by polymerization reaction, by using the second reaction gas, the by-products are removed; during the formation of the protective layer in each round, the problem that the by-products (such as C polymers) formed in the previous round become a barrier layer during the bombardment treatment in the next round, affecting the bombardment treatment effect, can be alleviated.

[0036] Further, the process for removing the byproduct reaction product by using the second reaction gas comprises a first reaction stage and a second reaction stage; wherein the chamber pressure of the first reaction stage is greater than the chamber pressure of the first reaction stage. By the first reaction stage with greater chamber pressure, the byproduct reaction product attached to the inner walls and structures of the etching chamber can be removed, especially the byproduct reaction product attached to the inner side wall surface and the top inner surface (such as the surface of the upper electrode plate and the upper cooling plate) of the etching chamber can be removed, and in the process, a part of the byproduct reaction product can fall on the wafer pedestal; then by the second reaction stage with smaller chamber pressure, the byproduct reaction product in the lower half area of the etching chamber (especially the surface of the wafer pedestal) can be removed, so that by the two rounds of removal process, the byproduct reaction product attached to the inner surface of the etching chamber and the structures can be effectively removed, and the problem that the byproduct reaction product (such as C polymer) attached due to dissociation, reaction, and attachment again during the plasma bombardment process again can interfere with the effect of the bombardment process can be effectively reduced.

[0037] Further, the process time of the first reaction stage is less than or equal to the waiting time for the reaction between the second reaction gas and the material of the protective layer. Since the first reaction stage is used to clean and remove the byproduct reaction product attached to the inner side wall surface and the top inner surface (such as the surface of the upper electrode plate and the upper cooling plate) of the etching chamber, if the reaction time is too long, the second reaction gas may react with the material of the protective layer (such as AlF3), such as forming Al x F y O z compound, which can cause the roughness of the protective layer to increase and the density and adhesion of the protective layer to decrease. By setting an appropriate upper limit of the process time, the loss of the material of the protective layer can be effectively avoided.

[0038] Further, one or more wafers are provided; before each round of process for the upper cooling plate is performed, a single wafer is placed in the etching chamber, and after each round of removal of the byproduct reaction product, the wafer is removed from the etching chamber. The chamber conditions in the formal production process can be simulated for processing, and the wafer pedestal and the lower electrode can be effectively protected, the interference with the surface of the wafer pedestal and the lower electrode can be reduced, and the cleaning difficulty of the etching chamber can be reduced.

[0039] Further, by using a light sheet without a dielectric layer on the surface, the interference of the oxidizing element (such as oxygen element) in the dielectric layer with the protective layer after dissociation can be avoided, for example, the reaction between the oxygen ion and AlF3may form Al x F y O z compound, which can cause the roughness of the protective layer to increase and the density and adhesion of the protective layer to decrease.

[0040] Further, by performing the bombardment treatment on the side wall of the gas supply hole, the surface-attached or residual alumina in the gas supply hole can be removed, compared to the bombardment on the side surface of the alumina plate facing the upper electrode plate, the inner side wall surface of the gas supply hole can be bombarded more deeply, the surface roughness can be increased by the bombardment, and the possibility of surface cracking of the inner side wall of the gas supply hole can be reduced by forming a protective layer, further reducing the problem of particle defects and improving the quality of the device.

[0041] Further, the first number of rounds is selected from 100 rounds to 300 rounds; and / or, the first duration is selected from 5 hrs to 15 hrs, the continuity of the processing process can be controlled from different dimensions, by more than two orders of magnitude of the number of rounds of processing or more than two orders of magnitude of the time required for the number of rounds of processing, the thickness of the protective layer formed can be effectively increased on the basis of maintaining the density and adhesion, further improving the service life of the upper cooling plate and reducing the replacement cost. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 is part of a flowchart of a maintenance method of an etching device in an embodiment of the present application;

[0043] Figure 2 is a cross-sectional structure schematic diagram of an etching device in an embodiment of the present application;

[0044] Figures 3 to 5 is a cross-sectional structure schematic diagram of the upper electrode plate and the upper cooling plate corresponding to each step in the maintenance method of the etching device in an embodiment of the present application.

[0045] BRIEF DESCRIPTION OF DRAWINGS

[0046] Etching chamber 1, wafer base 10, wafer 11, upper electrode plate 20, lower electrode plate 30, upper cooling plate 40, alumina plate 41, aluminum material plate 42, gas supply hole 50, protective layer 60. DETAILED DESCRIPTION

[0047] As described above, in the existing etching device, the upper electrode and the lower electrode are usually included, and the electrode plate is cooled by the cooling plate, for example, the upper electrode plate is cooled by the upper cooling plate to control the temperature of the upper electrode.

[0048] However, in the existing upper cooling plate, the first surface facing the wafer base is prone to surface cracking, and when the cracking is severe, the debris formed after the cracking falls on the wafer surface, causing particle defects.

[0049] It is found through research that the upper cooling plate component is easily affected by differences in process conditions, resulting in dramatic changes in surface temperature and potential, and then surface cracking occurs, especially in the case where the upper cooling plate itself contains a multi-layer structure or is in contact with other structures, the surface cracking phenomenon is more likely to occur due to the different thermal expansion coefficients of the adjacent layers of materials, at this time, the fragments formed after cracking on the side facing the wafer base are easy to fall onto the wafer surface, forming particle defects.

[0050] In an existing processing method, a certain time length can be set as the service life of the upper cooling plate, and the upper cooling plate is replaced regularly. However, the production cost of the above-mentioned scheme is too high, and the problem of continuing to appear particle defects due to untimely replacement still easily occurs.

[0051] In the embodiment of the present application, one or more rounds of processing processes are set, and the surface of the upper cooling plate is bombarded in each round of processing process; then at least part of the protective layer is formed on the surface of the upper cooling plate bombarded by the first reaction gas, which can form a protective layer on part of the surface of the upper cooling plate, effectively protect the surface of the upper cooling plate facing the wafer base, reduce the possibility of surface cracking of the first side of the upper cooling plate facing the wafer base, thereby reducing the problem of particle defects and improving the quality of the device. In addition, by first bombarding the surface of the upper cooling plate and then forming a protective layer, compared with directly forming a protective layer, the roughness of part of the surface of the upper cooling plate can be increased by bombardment, and the protective layer formed on this basis can have higher adhesion, thereby helping to improve the service life of the upper cooling plate and reduce the replacement cost. In addition, by forming through multiple rounds of processing processes, the density of the formed protective layer can be improved, and the adhesion between the protective layers formed by each round can be increased, further improving the service life of the upper cooling plate.

[0052] In order to make the above-mentioned purposes, features and benefits of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0053] Reference Figure 1 , Figure 1 is part of the flow chart of a maintenance method of an etching device in the embodiment of the present application.

[0054] The maintenance method of the etching device can include at least one round of processing processes on the upper cooling plate to form a protective layer on part of the surface of the upper cooling plate, and the part of the surface of the upper cooling plate at least includes a first side facing the wafer base; wherein each round of processing processes can include steps S11 to S12, and can also include step S13.

[0055] The following will be described in detail with reference to the accompanying drawings, Figure 1The maintenance method of the etching device and each step thereof are described.

[0056] Referring to Figure 2 , Figure 2 is a schematic diagram of a cross-sectional structure of an etching device in an embodiment of the present application.

[0057] The etching device can include an etching chamber 1, which can be provided with a wafer pedestal 10, an upper electrode plate 20, a lower electrode plate 30, and an upper cooling plate 40.

[0058] The wafer pedestal 10 is used to carry a wafer 11, and the upper electrode plate 20 and the lower electrode plate 30 can be installed on the upper and lower sides of the wafer pedestal 10 in parallel. By injecting a predetermined reaction gas between the upper electrode plate 20 and the lower electrode plate 30, and forming an electric field between the two electrodes sufficient to convert the reaction gas into a plasma gas state, the wafer 11 is etched using the plasma gas.

[0059] In Figure 2 In the etching device shown, the upper cooling plate 40 can be coupled with the upper electrode plate 20.

[0060] Specifically, the upper cooling plate 40 can include stacked aluminum oxide plates 41 and aluminum material plates 42 from bottom to top, and be disposed on the upper electrode plate 20, and there can be a non-zero gap between the aluminum oxide plates 41 and the upper electrode plate 20.

[0061] In some embodiments, a plurality of gas supply holes 50 for supplying gas can pass through the stacked aluminum material plates 42, aluminum oxide plates 41, and upper electrode plate 20.

[0062] Specifically, a plurality of gas supply holes 50 are formed in the upper electrode plate 20 of the etching device, which can make the reaction gas supplied into the etching chamber 1 through the upper electrode plate 20 be uniformly distributed.

[0063] It should be noted that in specific implementations, other appropriate structures of the upper cooling plate 40 and the upper electrode plate 20 can also be used, such as only the edge region being provided with gas supply holes 50, or not being provided with gas supply holes 50, and the upper electrode plate 20 being disposed on the upper cooling plate 40.

[0064] In a specific embodiment, the upper cooling plate 40 can include stacked aluminum oxide plates 41 and aluminum material plates 42 from bottom to top.

[0065] The aluminum oxide plate 41, also known as an anodized Al material plate, has a thermal expansion coefficient of about 6E-6 (1 / ℃), and the aluminum material plate 42 has a thermal expansion coefficient of about 30E-6 (1 / ℃), which has a difference of about 5 times.

[0066] Due to the large difference in the thermal expansion coefficients of the aluminum oxide plate 41 and the aluminum material plate 42, the anodic aluminum material is more likely to crack on the surface and fall on the surface of the silicon wafer, forming an aluminum oxide particle defect.

[0067] Figures 3 to 5 is a cross-sectional structure diagram of the upper electrode plate and the upper cooling plate corresponding to each step in the maintenance method of the etching device in the embodiment of the present application.

[0068] wherein, Figures 3 to 5 The part circled by the dashed line in Figure 2 is shown.

[0069] Referring to Figure 3 , the surface of the aluminum oxide plate 41 appears to be fragmented.

[0070] Specifically, due to the large difference in the thermal expansion coefficients of the aluminum oxide plate 41 and the aluminum material plate 42, the surface of the aluminum oxide plate 41 far from the aluminum material plate 42 is more likely to crack and appear fragmented.

[0071] Referring to Figure 4 , the part of the surface of the upper cooling plate 40 is subjected to bombardment treatment.

[0072] Specifically, in the structure shown, Figure 4 the upper cooling plate 40 can have the first and second faces shown, and the first face is arranged opposite to the second face.

[0073] In a specific implementation, at least the first face of the cooling plate 40 facing the wafer pedestal 10 can be subjected to bombardment.

[0074] More specifically, the side surface of the aluminum oxide plate 41 facing the upper electrode plate 20 can be subjected to bombardment treatment.

[0075] It should be noted that in the case of the gas supply hole 50, the sidewall of the gas supply hole 50 can also be subjected to bombardment.

[0076] Further, the gas used for the bombardment treatment can include argon, and the plasma used for the bombardment treatment includes argon plasma.

[0077] In the embodiment of the present application, the plasma used for the bombardment treatment is argon plasma. Since argon has a high atomic mass and chemical stability, it can produce microcrystal structures with more uniform size and higher precision, and therefore, bombardment with argon plasma can achieve better bombardment effect.

[0078] It should be noted that in the embodiments of the present application, other appropriate gases can also be used for the bombardment treatment, for example, other inert gases in addition to argon, for example, nitrogen (N2) is used.

[0079] Further, the process parameters of the bombardment treatment using argon plasma can include one or more of the following: the gas flow of the argon is selected from 700sccm to 800sccm; the process time is selected from 100 seconds to 140 seconds; the chamber pressure is selected from 20mT to 30mT; the high-frequency radio frequency power is selected from 3100W to 3500W; the low-frequency radio frequency power is selected from 3600W to 4000W.

[0080] The flow of the argon should not be too small, the process time should not be too short, the chamber pressure should not be too small, the high-frequency radio frequency power should not be too small, and the low-frequency radio frequency power should not be too small, otherwise the bombardment treatment will result in too little argon plasma; the flow of the argon should not be too large, the process time should not be too long, the chamber pressure should not be too large, the high-frequency radio frequency power should not be too large, and the low-frequency radio frequency power should not be too large, otherwise it may cause bombardment damage and increase the process cost.

[0081] In a specific embodiment, the flow of the argon can be selected from 700sccm to 800sccm, for example, selected from 720sccm to 780sccm, for example, 750sccm.

[0082] The process time can be selected from 100 seconds to 140 seconds, for example, selected from 110 seconds to 130 seconds, for example, 120 seconds.

[0083] The chamber pressure can be selected from 20mT to 30mT, for example, selected from 22mT to 28mT, for example, 25mT.

[0084] The high-frequency radio frequency power is selected from 3100W to 3500W, for example, selected from 3200W to 3400W, for example, 3300W.

[0085] The high-frequency radio frequency power is the Capacitively Coupled Plasma (CCP) high-frequency power, and by adjusting the high-frequency radio frequency power, the number of ions obtained by dissociating the plasma in the etching chamber can be adjusted.

[0086] The low-frequency radio frequency power is selected from 3600W to 4000W, for example, selected from 3700W to 3900W, for example, 3800W.

[0087] Among them, the low-frequency radio frequency power is the low-frequency power of capacitively coupled plasma (CCP). By adjusting the RF power, the ion energy when the plasma bombards the wafer in the process chamber can be adjusted.

[0088] Reference Figure 5 Using a first reactive gas, at least a portion of the protective layer 60 is formed on the surface of the upper cooling plate 40 after it has been bombarded.

[0089] Further, the method includes one or more of the following: the upper cooling plate faces the first side of the wafer substrate (e.g., Figure 4 The alumina plate 41 shown is made of alumina; the first reaction gas includes C. x F y The material of the protective layer 60 includes AlF3; the chemical reaction formula for forming at least a portion of the protective layer 60 on the surface of the upper cooling plate 40 after bombardment using the first reacting gas can be:

[0090] Al2O3+ C x F y AlF3 (s) + CO2 (g).

[0091] In this embodiment of the invention, when the material of the first surface of the upper cooling plate 40 facing the wafer substrate is alumina, particle defects are particularly prone to occur after cracking. This can be addressed by using a first reaction gas including C x F y The protective layer 60 is made of AlF3, forming a solid AlF3 that protects the surface of the alumina material and reduces the possibility of cracking.

[0092] Furthermore, the value of y is greater than the value of x.

[0093] In this embodiment of the invention, the first reacting gas includes C x F y The value of y is greater than the value of x. When the proportion of F element is large, after dissociation into plasma, the concentration of F plasma is higher, and it is less likely to undergo reverse reaction and more likely to react with Al ions. Compared with the reaction gas with a smaller proportion of F element, which leads to severe reverse reaction and weak reaction with Al ions, the present invention can enhance the forward reaction and better form solid AlF3 as a protective layer.

[0094] Furthermore, the first reacting gas C x F y It is a combination of one or more of the following: CF4, CF3, CF2.

[0095] It should be pointed out that, in Figure 5 The method shown uses CF4 as an example for illustration; however, gases such as CF3 and CF2 can also be mixed. In this embodiment of the invention, there are no restrictions on the specific combination of gases.

[0096] In this embodiment of the invention, one or more processing steps are performed, and a portion of the surface of the upper cooling plate 40 is bombarded in each processing step. Then, a first reactive gas is used to form at least a portion of the protective layer 60 on the bombarded surface of the upper cooling plate 40. This protective layer 60 can be formed on a portion of the surface of the upper cooling plate 40, effectively protecting the surface of the upper cooling plate 40 facing the wafer substrate, reducing the possibility of surface cracking on the first surface of the upper cooling plate 40 facing the wafer substrate, thereby mitigating particle defects and improving device quality. Furthermore, by bombarding a portion of the surface of the upper cooling plate 40 before forming the protective layer 60, compared to directly forming the protective layer 60, the roughness of the surface of the upper cooling plate 40 is increased through bombardment. The protective layer 60 formed on this basis has higher adhesion, thereby helping to improve the service life of the upper cooling plate 40 and reduce replacement costs. Furthermore, by forming the protective layer 60 through a multi-stage processing process, the density of the formed protective layer 60 can be improved, as well as the adhesion between the protective layers 60 formed in each stage, thereby further improving the service life of the upper cooling plate 40.

[0097] In some embodiments, each round of processing may further include: using a second reaction gas to remove byproducts; wherein the byproducts may be formed during the process of forming at least a portion of the protective layer 60 on a portion of the surface of the upper cooling plate 40 using a first reaction gas.

[0098] exist Figure 5 In the illustrated structure, a portion of the surface of the upper cooling plate 40 (such as the alumina plate 41) is made of alumina, and the first reactant gas includes C. x F y The method may include one or more of the following: the byproducts include C x The C x Adhered to the protective layer; the second reactive gas includes O2; the chemical reaction formula is:

[0099] C x + O2 CO2 (g).

[0100] Specifically, the by-product reaction product may, for example, be a long Carbon chain polymer complex formed by a polymerization reaction, which is hereinafter referred to as a C polymer.

[0101] In the case of a multi-round processing procedure, since the C polymer is attached to the surface of the formed protective layer 60, the C polymer formed in the previous round will block the bombardment treatment in the next round.

[0102] In the embodiments of the present application, since by-products, such as long Carbon chain polymer complexes (also referred to as C polymers) formed by a polymerization reaction, are formed during the formation of the protective layer, the by-products are removed by using a second reaction gas; and the problem that the by-products (such as C polymers) formed in the previous round become a blocking layer in the bombardment treatment in the next round, affecting the bombardment treatment effect, can be alleviated during the formation of the protective layer 60 in each round.

[0103] In some embodiments, the processing procedure for removing the by-products by using the second reaction gas can include a first reaction stage and a second reaction stage; wherein the chamber pressure of the first reaction stage can be greater than the chamber pressure of the second reaction stage.

[0104] Specifically, in the case of a greater chamber pressure, the second reaction gas can be distributed in the entire etching chamber; by using the first reaction stage with a greater chamber pressure, the by-products attached to each inner wall and each structure in the etching chamber can be removed, and in particular, a part of the by-products on the inner sidewall surface and the top inner surface (such as the surface of the upper electrode plate and the upper cooling plate) of the etching chamber can be removed.

[0105] In the case of a smaller chamber pressure, the second reaction gas is more distributed in the lower half area of the etching chamber; by using the second reaction stage with a smaller chamber pressure, the by-products in the lower half area of the etching chamber (in particular, on the surface of the wafer pedestal) can be removed.

[0106] Since a part of the by-products may fall on the wafer pedestal in the first reaction stage, the by-products in the lower half area of the etching chamber (in particular, on the surface of the wafer pedestal) can be removed again by using the second reaction stage.

[0107] In the embodiments of the present application, the byproduct attached to the inner walls and structures of the etching chamber can be removed in the first reaction stage with a high chamber pressure, and especially a part of the byproduct attached to the inner side wall surface and the top inner surface (e.g. the surface of the upper electrode plate and the upper cooling plate) of the etching chamber can be removed, and in the process, a part of the byproduct can fall on the wafer pedestal; and then the byproduct attached to the lower half area (especially the surface of the wafer pedestal) of the etching chamber can be removed in the second reaction stage with a low chamber pressure, so that the byproduct attached to the inner surface of the etching chamber and the structures can be effectively removed through the two rounds of removal processing, and the problem that the byproduct (e.g. C polymer) attached to the etching chamber can be dissociated, reacted and attached again to interfere with the bombardment processing effect when the plasma is used for bombardment processing again can be effectively reduced.

[0108] Further, the process time of the first reaction stage can be less than or equal to the waiting time for the second reaction gas to react with the material of the protective layer 60.

[0109] For example, the second reaction gas includes O2, and the material of the protective layer 60 is AlF3, and a suitable method such as a monitor wafer can be used to grow the protective layer 60, and then the waiting time for the second reaction gas to react with the material of the protective layer 60 can be determined through experiments.

[0110] In the embodiments of the present application, the process time of the first reaction stage is less than or equal to the waiting time for the second reaction gas to react with the material of the protective layer 60. Since the first reaction stage is used to clean and remove the byproduct attached to the inner side wall surface and the top inner surface (e.g. the surface of the upper electrode plate and the upper cooling plate) of the etching chamber, and the reaction time is too long, the second reaction gas can react with the material of the protective layer 60 (e.g. AlF3), such as forming Al x F y O z compound, which can cause the roughness of the protective layer 60 to increase and the density and adhesion of the protective layer 60 to decrease. By setting a suitable upper limit of the process time, the loss of the material of the protective layer 60 can be effectively avoided.

[0111] Further, the method includes one or more of the following: the chamber pressure of the first reaction stage is selected from 180mT to 220mT; the process time of the first reaction stage is selected from 10s to 30s; the chamber pressure of the second reaction stage is selected from 30mT to 50mT; and the process time of the second reaction stage is selected from 10s to 15s.

[0112] The chamber pressure of the first reaction stage should not be too small, and the process duration of the first reaction stage should not be too short, the chamber pressure of the second reaction stage should not be too small, and the process duration of the second reaction stage should not be too small, otherwise, it will lead to insufficient reaction; the chamber pressure of the first reaction stage should not be too large, and the process duration of the first reaction stage should not be too long, the chamber pressure of the second reaction stage should not be too large, and the process duration of the second reaction stage should not be too large, otherwise, it may lead to structure damage or increased production cost.

[0113] In one specific embodiment, the chamber pressure of the first reaction stage can be selected from 180mT to 220mT, for example, from 190mT to 210mT, for example, 200mT.

[0114] The process duration of the first reaction stage can be selected from 10s to 30s, for example, from 15s to 25s, for example, 20s.

[0115] The chamber pressure of the second reaction stage is selected from 30mT to 50mT, for example, from 35mT to 45mT, for example, 30mT.

[0116] The process duration of the second reaction stage is selected from 10s to 15s, for example, from 11s to 14s, for example, 12s.

[0117] The process duration of the second reaction stage is selected from 10s to 15s, for example, from 11s to 14s, for example, 12s.

[0118] In one specific embodiment, the second reaction gas can be O2, and the process parameters of the treatment process using O2 to remove by-product can further include one or more of the following: the gas flow of the O2 is selected from 1000sccm to 1400sccm; the high-frequency radio frequency power is selected from 1300W to 1700W; the low-frequency radio frequency power is selected from 800W to 1200W.

[0119] The gas flow of the O2 should not be too small, the upper electrode power should not be too small, and the lower electrode power should not be too small, otherwise, it will lead to insufficient reaction; the gas flow of the O2 should not be too large, the upper electrode power should not be too large, and the lower electrode power should not be too large, otherwise, it may lead to structure damage or increased production cost.

[0120] The gas flow of the O2 can be selected from 1000sccm to 1400sccm, for example, from 1100sccm to 1300sccm, for example, 1200sccm.

[0121] The high frequency RF power can be selected from 1300 W to 1700 W, for example, from 1400 W to 1600 W, for example, 1500 W.

[0122] The low frequency RF power can be selected from 800 W to 1200 W, for example, from 900 W to 1100 W, for example, 1000 W.

[0123] In some embodiments, the method can further comprise: providing one or more wafers; placing a single wafer into the etching chamber before each round of processing on the upper cooling plate, and removing the wafer from the etching chamber after each round of removing the byproduct reaction product.

[0124] In the embodiments of the present application, by providing one or more wafers; placing a single wafer into the etching chamber before each round of processing on the upper cooling plate, and removing the wafer from the etching chamber after each round of removing the byproduct reaction product. The processing can be carried out by simulating the chamber conditions in the formal production process, while effectively protecting the wafer pedestal and the lower electrode, reducing the interference on the surface of the wafer pedestal and the lower electrode, and reducing the cleaning difficulty of the etching chamber.

[0125] Further, the number of wafers can be multiple; wherein in each round of processing, the multiple wafers are placed in turn according to a preset cycle sequence.

[0126] In the embodiments of the present application, by setting multiple wafers to be replaced in turn, the situation of overheating of a single wafer during bombardment processing and formation of a protective layer can be avoided, thereby improving the reuse rate of the wafer.

[0127] Further, the wafer can be a light wafer without a medium layer on the surface.

[0128] The light wafer is also called a dummy wafer, a raw wafer, etc., and can be formed by a crystal ingot, for example.

[0129] The medium layer can be silicon oxide, for example, SiO2.

[0130] It should be particularly pointed out that the conventional light wafer on the market is usually a light wafer with a medium layer to meet the demand for reducing storage and transportation costs.

[0131] In the embodiments of the present application, by using a light wafer without a medium layer on the surface, the interference of the oxidizing elements (such as oxygen elements) in the medium layer on the protective layer 60 after dissociation due to its high oxidizing property can be avoided. For example, oxygen ions can react with AlF3 to form Al x Fy O z The compound causes the roughness of the protective layer 60 to become large, and the density and adhesion to decrease.

[0132] In Figures 2 to 5 In the illustrated structure, the upper cooling plate 40 includes stacked aluminum oxide plates 41 and aluminum material plates 42 from bottom to top, and is disposed on the upper electrode plate 20, with a non-zero gap between the aluminum oxide plates 41 and the upper electrode plate 20, wherein a plurality of gas supply holes 50 for supplying gas pass through the stacked aluminum material plates 42, aluminum oxide plates 41, and upper electrode plate 20.

[0133] In the case of the gas supply holes 50 described above, the step of performing bombardment treatment on part of the surface of the upper cooling plate 40 can include: performing bombardment treatment on the side wall of the gas supply hole 50 and the side surface of the aluminum oxide plate 41 facing the upper electrode plate 20; and forming at least part of the protective layer 60 on the surface of the upper cooling plate 40 after bombardment includes: forming at least part of the protective layer 60 on the side wall of the gas supply hole 50 and the side surface of the aluminum oxide plate 41 facing the upper electrode plate 20.

[0134] In embodiments of the present application, by performing bombardment treatment on the side wall of the gas supply hole 50, the surface-attached or residual aluminum oxide in the gas supply hole 50 can be removed, compared to only bombardment on the side surface of the aluminum oxide plate 41 facing the upper electrode plate 20, the inner side wall surface of the gas supply hole 50 can be bombarded more deeply, the surface roughness can also be increased by bombardment, and the possibility of surface cracking of the inner side wall of the gas supply hole 50 can be reduced by forming the protective layer 60, further reducing the problem of particle defects and improving device quality.

[0135] In some embodiments, the first reaction gas includes CF4, and the process parameters for forming at least part of the protective layer on the surface of the upper cooling plate after bombardment can include one or more of: the gas flow of the CF4 is selected from: 80sccm to 120sccm; the process time is selected from: 100 seconds to 140 seconds; the chamber pressure is selected from: 60mT to 100mT; the high-frequency radio frequency power is selected from: 1200W to 1800W; and the low-frequency radio frequency power is selected from: 400W to 600W.

[0136] The gas flow of CF4 should not be too small, the process time should not be too small, the chamber pressure should not be too small, the upper electrode power should not be too small, and the lower electrode power should not be too small, otherwise it will lead to insufficient reaction; the gas flow of CF4 should not be too large, the process time should not be too large, the chamber pressure should not be too large, the upper electrode power should not be too large, and the lower electrode power should not be too large, otherwise it may cause structural damage or increase production cost.

[0137] The gas flow of CF4 is selected from 80sccm to 120sccm, for example, selected from 90sccm to 110sccm, for example, 100sccm.

[0138] The process time is selected from 100 seconds to 140 seconds, for example, selected from 100 seconds to 120 seconds, for example, 110 seconds.

[0139] The chamber pressure is selected from 60mT to 100mT, for example, selected from 70mT to 90mT, for example, 80mT.

[0140] The frequency of the high-frequency RF power can be 40 or 60MHz, which can be provided by a high-frequency RF power source, for example, the electrical connection of the high-frequency RF power source can be connected to at least one of the upper electrode or the lower electrode.

[0141] The high-frequency RF power can be selected from 1200W to 1800W, for example, selected from 1400W to 1600W, for example, 1500W.

[0142] The frequency of the low-frequency RF power can be about 13MHz, which can be provided by a low-frequency RF power source, for example, the electrical connection of the low-frequency RF power source can be connected to at least one of the upper electrode or the lower electrode.

[0143] The low-frequency RF power can be selected from 400W to 600W, for example, selected from 450W to 550W, for example, 500W.

[0144] In a specific embodiment, the first reaction gas can also contain argon; wherein the gas flow of the argon can be selected from 250sccm to 350sccm.

[0145] The gas flow of the argon can be selected from 280sccm to 320sccm, for example, 300sccm.

[0146] In a specific implementation, the physical bombardment treatment with argon can be continued during the process of forming a protective layer by chemical reaction, further improving the density and adhesion of the protective layer formed in each reaction.

[0147] As to how to select argon as the bombardment gas and the selection of the alternative gas, reference can be made to the foregoing and the description of the bombardment treatment method shown in the figures, which will not be repeated here. Figure 4 The description of the bombardment treatment method shown in the figures will not be repeated here.

[0148] In some embodiments, the total process duration of the at least one round of treatment process on the upper cooling plate can be greater than or equal to a first duration; and / or the total number of rounds of the at least one round of treatment process on the upper cooling plate can be greater than or equal to a first number of rounds.

[0149] In specific implementations, the controllability and accuracy of the process treatment can be improved by setting a certain total process duration and / or by setting a certain total number of rounds to control the continuous operation of the treatment process from different dimensions.

[0150] Further, the first number of rounds can be selected from 100 rounds to 300 rounds; and / or the first duration can be selected from 5 hrs to 15 hrs.

[0151] In the embodiments of the present application, the first number of rounds is selected from 100 rounds to 300 rounds; and / or the first duration is selected from 5 hrs to 15 hrs, which can control the continuous operation of the treatment process from different dimensions. By exceeding the number of rounds by two orders of magnitude or the duration required for the number of rounds by two orders of magnitude, the thickness of the protective layer formed can be effectively increased on the basis of maintaining the density and adhesion, further improving the service life of the upper cooling plate and reducing the replacement cost.

[0152] In the embodiments of the present application, an etching device is also provided, which is described in combination with the foregoing Figures 2 to 5 The etching device can include a wafer base 10, a coupled upper electrode plate 20, and an upper cooling plate 40 for cooling the upper electrode plate 20. Part of the surface of the upper cooling plate 40 forms a protective layer 60, and the part of the surface of the upper cooling plate 40 at least includes a first surface facing the wafer base 10. The protective layer 60 is formed by at least one round of treatment process, each round of treatment process including bombardment treatment on the part of the surface of the upper cooling plate 40, and then using a first reaction gas to form at least a part of the protective layer 60 on the surface of the upper cooling plate 40 after bombardment.

[0153] Further, the material of the part of the surface of the upper cooling plate 40 can include aluminum oxide, and / or the material of the protective layer 60 can include AlF3.

[0154] In the embodiment of the present application, the protective layer 60 is formed by at least one round of processing, and at least a part of the protective layer 60 is formed on the surface of the upper cooling plate 40 after the surface of the upper cooling plate 40 is bombarded in each round of processing and then the first reaction gas is used, so that the protective layer 60 can effectively protect the surface of the upper cooling plate 40 facing the wafer pedestal, reduce the possibility of surface cracking of the first surface of the upper cooling plate 40 facing the wafer pedestal, thereby reducing the problem of particle defects and improving the quality of the device. In addition, by first bombarding the surface of the upper cooling plate 40 and then forming the protective layer 60, compared with directly forming the protective layer 60, the roughness of the surface of the upper cooling plate 40 can be increased by bombardment, and the protective layer 60 formed on this basis can have higher adhesion, thereby helping to improve the service life of the upper cooling plate 40 and reduce the replacement cost. In addition, by forming through multiple rounds of processing, the density of the formed protective layer 60 can be improved, and the adhesion between the protective layers 60 formed in each round can be increased, thereby further improving the service life of the upper cooling plate 40.

[0155] For more information about the etching device, please refer to the relevant description of the maintenance method of the etching device described above, which will not be repeated here.

[0156] It should be understood that the term "and / or" herein is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can represent: A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in this paper represents that the front and rear associated objects are a "or" relationship. As used herein, unless otherwise explicitly stated, the term "or" encompasses all possible combinations, unless not feasible. For example, if it is stated that a component can include A or B, then unless explicitly stated otherwise or not feasible, the component can include A, or B, or A and B. As a second example, if it is stated that a component can include A, B or C, then unless explicitly stated otherwise or not feasible, the component can include A, or B, or C, or A and B, or A and C, or B and C, or A and B and C.

[0157] The "multiple" appearing in the embodiments of the present application means two or more than two.

[0158] The relational terms herein, such as first, second, and the like, are used solely to distinguish one entity or action from another, without necessarily requiring or implying any actual relationship or order between or among entities or actions. Moreover, the words "comprises," "has," and "includes" and other similar forms are intended to be equivalent in meaning and be open-ended, such that any item or list of items following any form of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the items specifically listed.

[0159] It should be noted that the sequence of the steps in the embodiments does not represent the limitation of the execution sequence of the steps.

[0160] In the foregoing specification, embodiments have been described with reference to numerous specific details that can vary from implementation to implementation. Certain modifications and changes can be made thereto, and it is intended to embrace all such modifications and changes as fall within the scope of the application. It is to be understood that the foregoing description and example have been given by way of illustration only, and that other embodiments will become apparent to those skilled in the art from this complete specification and the example. The true scope and spirit of the application is indicated by the following claims. The sequence of steps shown in the drawings is also intended to be illustrative only, and is not intended to be limiting to any particular sequence of steps. Accordingly, those skilled in the art will recognize that the steps could be performed in a different order, while still implementing the same method.

[0161] In the drawings and specification, there have been disclosed exemplary embodiments. However, many variations and modifications can be made to these embodiments. Accordingly, while specific terminology has been employed, they are used in the generic and descriptive sense only, and not for purposes of limitation.

[0162] Although the present application has been disclosed as above, the present application is not limited to the above. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and the scope of protection of the present application should be defined by the scope defined by the claims.

Claims

1. A method of maintaining an etching apparatus, characterized by, The etching apparatus comprises a wafer base, a coupled upper electrode plate, and an upper cooling plate for cooling the upper electrode plate; The method comprises: performing at least one round of processing on the upper cooling plate to form a protective layer on a portion of the surface of the upper cooling plate, the portion of the surface of the upper cooling plate at least including a first surface facing the wafer base; wherein each round of processing comprises: bombarding a portion of the surface of the upper cooling plate; using a first reaction gas to form at least a portion of the protective layer on the bombarded surface of the upper cooling plate.

2. The method of claim 1, wherein, The method comprises one or more of: the material of the first surface of the upper cooling plate facing the wafer base is aluminum oxide; The first reaction gas includes C x F y : the material of the protective layer comprises AlF3; the chemical reaction formula for using the first reaction gas to form at least a portion of the protective layer on the bombarded surface of the upper cooling plate is: Al2O3+ C x F y AlF3 (s) +CO2 (g); wherein the first reaction gas C x F y CF4, CF3, CF2.

3. The method of claim 1, wherein, each round of processing further comprises: using a second reaction gas to remove a byproduct; wherein the byproduct is formed during the process of using the first reaction gas to form at least a portion of the protective layer on a portion of the surface of the upper cooling plate.

4. The method of claim 3, wherein, A portion of a surface of the upper cooling plate includes aluminum oxide, the first reaction gas includes C x F y ; The method comprises one or more of: The side reaction products include C x , the C x attached to the protective layer; the second reaction gas comprises O2; The chemical reaction is: C x + O2 CO2 (g); wherein the first reaction gas C x F y CF4, CF3, CF2.

5. The method of claim 3, wherein, the process of using the second reaction gas to remove the byproduct comprises a first reaction stage and a second reaction stage; wherein the chamber pressure of the first reaction stage is greater than the chamber pressure of the second reaction stage.

6. The method of claim 5, wherein, the process duration of the first reaction stage is less than or equal to the waiting duration for the second reaction gas to react with the material of the protective layer.

7. The method according to claim 5 or 6, characterized in that, The method comprises one or more of: the chamber pressure of the first reaction stage is selected from 180mT to 220mT; the process duration of the first reaction stage is selected from 10s to 30s; the chamber pressure of the second reaction stage is selected from 30mT to 50mT; the process duration of the second reaction stage is selected from 10s to 15s.

8. The method of claim 5, wherein, when the second reaction gas is O2, the process parameters for the process of using O2 to remove the byproduct further comprise one or more of: the gas flow of the O2 is selected from 1000sccm to 1400sccm; the high-frequency RF power is selected from 1300W to 1700W; the low-frequency RF power is selected from 800W to 1200W.

9. The method of claim 3, wherein, The method further comprises: providing one or more wafers; placing a single wafer into the etching chamber before each round of processing on the upper cooling plate, and removing the wafer from the etching chamber after each round of removing the byproduct.

10. The method of claim 9, wherein, the number of wafers is multiple; wherein in each round of processing, the multiple wafers are replaced according to a predetermined cycle sequence.

11. The method of claim 9, wherein, the wafers are light wafers without a dielectric layer on the surface.

12. The method of claim 1, wherein, the upper cooling plate comprises stacked aluminum oxide plates and aluminum material plates from bottom to top, and is placed on the upper electrode plate, and there is a non-zero gap between the aluminum oxide plates and the upper electrode plate, wherein a plurality of gas supply holes for supplying gas penetrate through the stacked aluminum material plates, aluminum oxide plates, and upper electrode plate; bombarding a portion of a surface of the upper cooling plate, including: bombarding a sidewall of the gas supply hole and a side surface of the aluminum oxide plate facing the upper electrode plate; forming at least a portion of the protective layer on the bombarded surface of the upper cooling plate, including: forming at least a portion of the protective layer on the sidewall of the gas supply hole and the side surface of the aluminum oxide plate facing the upper electrode plate.

13. The method of claim 1 or 12, wherein, The gas used for the bombarding process includes argon, and the plasma used for the bombarding process includes argon plasma.

14. The method of claim 13, wherein, The process parameters for the bombarding process using argon plasma include one or more of the following: The gas flow of the argon is selected from 700 sccm to 800 sccm; The process time is selected from 100 seconds to 140 seconds; The chamber pressure is selected from 20 mT to 30 mT; The high-frequency radio frequency power is selected from 3100 W to 3500 W; The low-frequency radio frequency power is selected from 3600 W to 4000 W.

15. The method of claim 1 or 12, wherein, The first reaction gas includes CF4, and the process parameters for forming at least a portion of the protective layer on the bombarded surface of the upper cooling plate using the CF4 include one or more of the following: The gas flow of the CF4 is selected from 80 sccm to 120 sccm; The process time is selected from 100 seconds to 140 seconds; The chamber pressure is selected from 60 mT to 100 mT; The high-frequency radio frequency power is selected from 1200 W to 1800 W; The low-frequency radio frequency power is selected from 400 W to 600 W.

16. The method of claim 15, wherein: the total process time of the at least one round of process on the upper cooling plate is greater than or equal to a first time; and / or the total number of rounds of the at least one round of process on the upper cooling plate is greater than or equal to a first number of rounds.

17. The method of claim 16, wherein: the first number of rounds is selected from 100 rounds to 300 rounds; and / or the first time is selected from 5 hrs to 15 hrs.

18. An etching apparatus, comprising: The etching apparatus includes a wafer base, a coupled upper electrode plate, and an upper cooling plate for cooling the upper electrode plate; wherein a portion of a surface of the upper cooling plate forms a protective layer, and the portion of the surface of the upper cooling plate includes at least a first surface facing the wafer base; The protective layer is formed by at least one round of process, each round of process including bombarding a portion of a surface of the upper cooling plate, and forming at least a portion of the protective layer on the bombarded surface of the upper cooling plate using a first reaction gas.

19. The etching apparatus of claim 18, wherein, The material of the portion of the surface of the upper cooling plate includes aluminum oxide, and / or the material of the protective layer includes AlF3.

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