Control separation blade, manufacturing method thereof and dry etching method
By using the control pad of the patterned oxide layer in the dry etching process, the problem of under-etching of product sheets caused by no patterned control pad is solved, and sensitive and accurate control of the product etching amount is achieved, and product yield is improved.
Patent Information
- Application Number
- CN202311607379.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-28
- Publication Date
- 2025-05-30
AI Technical Summary
In the dry etching process, existing patternless control pads consume more etching gas, resulting in under-etching of product sheets and affecting product yield.
A control pad is provided on which a patterned oxide layer is formed, and the material of the patterned oxide layer is the same as the material of the film layer to be etched in the product sheet. The product sheet and the control pad are placed in the process cavity of the dry etching machine, and the dry etching process is performed to etch the film layer to be etched and the patterned oxide layer.
The patterned oxide layer reduces the etching amount and reduces the consumption of etching gas, and achieves sensitive and accurate control of the etching amount of product pieces, avoids the problem of under-etching of product pieces, and improves product yield.
Smart Images
Figure CN120072640A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of semiconductor technology, and particularly relates to a masking sheet, a manufacturing method thereof, and a dry etching method. Background Art
[0002] With the development of integrated circuit manufacturing processes, the requirements for the integration density and manufacturing precision of semiconductor devices are increasing day by day. The size of semiconductor devices is becoming more and more miniaturized. In the dry etching process, the etching amount will affect the yield of semiconductor devices. Therefore, during the etching process, under-etching or over-etching needs to be avoided. Currently, during the execution of the dry etching process, a masking sheet and a product wafer are etched together to monitor the process machine and process conditions through the masking sheet. However, the current masking sheet is usually a non-patterned masking sheet, and the material of the non-patterned masking sheet is the same as the film layer to be etched on the product wafer. During the etching process, the non-patterned masking sheet will consume more etching gas, resulting in under-etching of the product wafer. Specifically, as shown in Figure 1 shown, the average value of the etching amount of the product wafer 10 is 42 Å to 43 Å, and this etching amount does not meet the process requirements, affecting the product yield. Summary of the Invention
[0003] The purpose of the present invention is to provide a masking sheet, a manufacturing method thereof, and a dry etching method to solve the problem of under-etching of the product wafer.
[0004] To solve the above technical problems, the present invention provides a dry etching method, including:
[0005] providing a masking sheet and a product wafer, wherein the product wafer has a film layer to be etched, the masking sheet has a patterned oxide layer, the patterned oxide layer exposes a part of the surface of the masking sheet, and the material of the patterned oxide layer is the same as the material of the film layer to be etched; and,
[0006] placing the product wafer and the masking sheet in a process chamber of a dry etching machine and performing a dry etching process to etch the film layer to be etched and the patterned oxide layer, wherein, in the dry etching process, the reaction of the etching gas with the patterned oxide layer and the masking sheet is different.
[0007] Optionally, in the dry etching method, a hard mask layer is formed on the product wafer, the hard mask layer and the product wafer have a shallow trench, the shallow trench extends from the top surface of the hard mask layer to the product wafer, the film layer to be etched fills the shallow trench and the top surface of the film layer to be etched is higher than the top surface of the product wafer.
[0008] Optionally, in the dry etching method, the patterned oxide layer has an opening that exposes a partial surface of the mask, and the width of the opening is greater than or equal to the width of the shallow trench.
[0009] Optionally, in the dry etching method, the thickness of the patterned oxide layer is 400 Å to 600 Å, and the thickness of the film layer to be etched is 2150 Å to 2350 Å; when performing the dry etching process, the etching depth of the patterned oxide layer is the same as that of the film layer to be etched, and the etching depth of the patterned oxide layer and the film layer to be etched is 50 Å to 200 Å.
[0010] Optionally, in the dry etching method, the materials of both the mask and the product wafer are silicon; the materials of both the patterned oxide layer and the film layer to be etched are silicon oxide.
[0011] Optionally, in the dry etching method, the process temperature of the dry etching process is 250 °C to 300 °C, and the etching gas includes hydrogen fluoride and ammonia.
[0012] Based on the same inventive concept, the present invention also provides a method for manufacturing a mask for a dry etching process, including:
[0013] Providing a mask;
[0014] Forming a patterned photoresist layer on the mask;
[0015] Using the patterned photoresist layer as a mask to oxidize the mask to form a patterned oxide layer, the material of the patterned oxide layer is the same as that of the film layer to be etched in the product wafer, and the material of the patterned oxide layer is different from that of the mask;
[0016] Removing the patterned photoresist layer to expose the surface of the mask not covered by the patterned oxide layer; and,
[0017] Performing a wet cleaning process on the mask with the patterned oxide layer.
[0018] Optionally, in the method for manufacturing the mask, a dry stripping machine is used for the oxidation treatment, and the process gas for the oxidation treatment includes oxygen; and,
[0019] Using the dry stripping machine to remove the patterned photoresist layer, and the process gas for removing the patterned photoresist layer includes oxygen and nitrogen.
[0020] Optionally, in the method for manufacturing the blocking sheet, the materials of the blocking sheet and the product sheet are both silicon; the materials of the patterned oxide layer and the film layer to be etched are both silicon oxide.
[0021] Based on the same inventive concept, the present invention also provides a blocking sheet, on which a patterned oxide layer is formed. The patterned oxide layer exposes a part of the surface of the blocking sheet. The material of the patterned oxide layer is the same as that of the film layer to be etched in the product sheet, and the material of the patterned oxide layer is different from that of the blocking sheet.
[0022] In the blocking sheet, its manufacturing method, and the dry etching method provided by the present invention, a patterned oxide layer is formed on the blocking sheet. The patterned oxide layer exposes a part of the surface of the blocking sheet. The material of the patterned oxide layer is the same as that of the film layer to be etched in the product sheet. During the etching process, the product sheet and the blocking sheet are placed in the process chamber of a dry etching machine, and a dry etching process is performed to etch the film layer to be etched and the patterned oxide layer. Since the patterned oxide layer has a pattern, the etching amount can be reduced, thereby reducing the consumption of etching gas in the dry etching process. In addition, since the material of the patterned oxide layer is different from that of the blocking sheet, in the dry etching process, the reactions of the etching gas with the patterned oxide layer and the blocking sheet are different. The patterned oxide layer will consume the etching gas in the dry etching process, while the blocking sheet has chemical stability in the dry etching process. Therefore, the synergistic effect of the two can be utilized to control the etching amount of the film layer to be etched on the product sheet in the dry etching process, thereby achieving the purpose of controlling the etching amount of the product sheet, and thus realizing sensitive and accurate control of the etching amount of the product sheet and avoiding the problem of under-etching of the product sheet. Description of the Drawings
[0023] Figure 1 is a surface hot spot scan diagram of a product sheet in the prior art after performing a dry etching process;
[0024] Figure 2 is a schematic flow chart of the dry etching method according to an embodiment of the present invention;
[0025] Figures 3 to 8 is a schematic cross-sectional view of the structure formed in the dry etching method according to an embodiment of the present invention;
[0026] Figure 9 is a schematic principle diagram when performing a dry etching process on a product sheet and a blocking sheet in the dry etching method according to an embodiment of the present invention;
[0027] Figure 10 is a surface hot spot scan diagram of a product sheet in the dry etching method according to an embodiment of the present invention after performing a dry etching process;
[0028] Figure 11 is a schematic flow chart of a method for manufacturing a control stop film according to an embodiment of the present invention;
[0029] Figures 12 to 14 is a schematic cross-sectional view of a structure formed in the method for manufacturing a control stop film according to an embodiment of the present invention;
[0030] Among them, the reference numerals are explained as follows:
[0031] 10 - product wafer;
[0032] 100 - control stop film; 110 - patterned oxide layer; 110a - opening; 120 - patterned photoresist layer; 130 - polymer;
[0033] 200 - product wafer; 200a - shallow trench; 210 - film layer to be etched; 220 - hard mask layer; 221 - silicon oxide layer; 222 - silicon nitride layer; 300 - process chamber; 310 - carrier member. Detailed Embodiment
[0034] The control stop film, the method for manufacturing the same, and the dry etching method proposed by the present invention are further described in detail below with reference to the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are all in a very simplified form and use non-precise scales, only for the purpose of facilitating and clearly assisting in explaining the objectives of the embodiments of the present invention.
[0035] Figure 2 is a schematic flow chart of a dry etching method according to an embodiment of the present invention. As Figure 2 shown, the dry etching method provided in this embodiment includes:
[0036] Step S1: Provide a control stop film and a product wafer, where the product wafer has a film layer to be etched, the control stop film has a patterned oxide layer, the patterned oxide layer exposes a part of the surface of the control stop film, the material of the patterned oxide layer is the same as the material of the film layer to be etched, and the material of the patterned oxide layer is different from the material of the control stop film; and,
[0037] Step S2: Place the product wafer and the control stop film in a process chamber of a dry etching machine tool, and perform a dry etching process to etch the film layer to be etched and the patterned oxide layer. Among them, in the dry etching process, the etching gas reacts differently with the patterned oxide layer and the control stop film.
[0038] Figures 3 to 8 is a schematic cross-sectional view of a structure formed in the dry etching method according to an embodiment of the present invention; Figure 9It is a schematic diagram of the principle when performing a dry etching process on a product wafer and a dummy wafer in the dry etching method of an embodiment of the present invention. The following will be combined with Figures 3 to 9 to describe the dry etching method provided in this embodiment in more detail.
[0039] Refer to Figure 3 and Figure 7 As shown, in step S1, a dummy wafer 100 and a product wafer 200 are provided. The product wafer 200 has an etching target film layer 210. The dummy wafer 100 has a patterned oxide layer 110. The patterned oxide layer 110 exposes a part of the surface of the dummy wafer 100. The material of the patterned oxide layer 110 is the same as the material of the etching target film layer 210, and the material of the patterned oxide layer 110 is different from the material of the dummy wafer 100. Among them, the materials of the patterned oxide layer 110 and the etching target film layer 210 are both silicon oxide (SiO 2 ). Since the patterned oxide layer 110 has a pattern, the etching amount of the patterned oxide layer 110 can be reduced, thereby reducing the consumption of etching gas in the dry etching process.
[0040] In this embodiment, the material of the dummy wafer 100 is the same as the material of the product wafer 200. The material of the dummy wafer 100 and the product wafer 200 can be silicon (Si), that is, the dummy wafer 100 and the product wafer 200 can be silicon substrates. Further, the dummy wafer 100 is also called a control wafer or a blocking wafer, and can be used to monitor process equipment and process conditions.
[0041] As Figure 6 shown, a hard mask layer 220 is formed on the product wafer 200. The hard mask layer 220 and the product wafer 200 have a shallow trench 200a. The shallow trench 200a extends from the top surface of the hard mask layer 220 into the product wafer 200. As Figure 7 shown, the etching target film layer 210 fills the shallow trench 200a. The thickness of the etching target film layer can be 2150 Å to 2350 Å, such as 2150 Å, 2250 Å or 2350 Å. Among them, the top surface of the etching target film layer 210 is higher than the top surface of the product wafer 200, and the top surface of the etching target film layer 210 can be flush with the top surface of the hard mask layer 220, or the top surface of the etching target film layer 210 can be higher than the top surface of the hard mask layer 220, or the top surface of the etching target film layer 210 can be lower than the top surface of the hard mask layer 220. In this embodiment, the case where the top surface of the etching target film layer 210 is flush with the top surface of the hard mask layer 220 is taken as an example for description.
[0042] Specifically, the method for forming the shallow trench 200a in the product wafer 200 includes: First, as Figure 5As shown, a hard mask layer 220 is formed on the product wafer 200. The hard mask layer 220 includes a silicon oxide layer 221 and a silicon nitride layer 222 located on the silicon oxide layer 221. Then, a patterned photoresist layer (not shown) is formed on the hard mask layer 220, and the patterned photoresist layer exposes a part of the hard mask layer 220. Next, as Figure 6 shown, using the patterned photoresist layer as a mask, the exposed hard mask layer 220 and the product wafer 200 are etched to form a shallow trench 200a. The shallow trench 200a penetrates through the hard mask layer 220 and extends into the product wafer 200. Next, as Figure 7 shown, an etch target film layer 210 is formed in the shallow trench 200a. The top surface of the etch target film layer 210 is flush with the top surface of the hard mask layer 220. The etch target film layer 210 is used to form a shallow trench isolation (STI) structure.
[0043] In this embodiment, as Figure 3 shown, the patterned oxide layer 110 on the spacer 100 has an opening 110a. The opening 110a exposes a part of the surface of the spacer 100, and the width of the opening 110a is greater than or equal to the width of the shallow trench 200a. In this way, the density of the pattern of the patterned oxide layer 110 can be less than or equal to the density of the shallow trenches 200a in the product wafer 200, which is beneficial to reducing the consumption of the etch gas in the subsequent dry etching process in the area of the patterned oxide layer 110.
[0044] In this embodiment, the thickness of the patterned oxide layer 110 can be 400 Å to 600 Å, such as 400 Å, 500 Å, 550 Å or 600 Å.
[0045] Next, referring to Figure 4 and combining with Figure 8 and Figure 9As shown, step S2 is performed. The product wafer 200 and the mask wafer 100 are placed in the process chamber 300 of a dry etching machine tool, and a dry etching process is performed to etch the film layer to be etched 210 and the patterned oxide layer 110. In the dry etching process, the mask wafer 100 is used as a companion wafer to be etched together with the product wafer 200. Since the material of the patterned oxide layer 110 is different from that of the mask wafer 100, the reaction of the etching gas with the patterned oxide layer 110 and the mask wafer 100 is different. Specifically, the patterned oxide layer 110 consumes the etching gas in the dry etching process, while the mask wafer 100 has chemical stability in the dry etching process and does not consume the etching gas. The flow rate of the etching gas consumed by the mask wafer 100 can be reduced, and the flow rate of the etching gas on the surface of the product wafer 200 can be increased. Therefore, by utilizing the synergistic effect of the two, by controlling the flow rate of the etching gas on the surface of the product wafer 200, the etching amount of the film layer to be etched 210 of the product wafer 200 in the dry etching process can be controlled, thereby achieving the purpose of controlling the etching amount of the product wafer 200, and thus realizing sensitive and accurate control of the etching amount of the product wafer 200, avoiding the problem of under-etching of the product wafer 200, and improving the product yield.
[0046] In this embodiment, the dry etching machine tool can be a plasma etching machine tool. A carrier member 310 is provided in the process chamber 300 of the dry etching machine tool for carrying the product wafer 200 and the mask wafer 100. During the execution of the dry etching process, an etching gas is introduced into the process chamber 300 of the dry etching machine tool. The etching gas includes an effective etching gas and a catalytic gas to etch the film layer to be etched 210, that is, to perform backetching on the film layer to be etched 210 in the shallow trench 200a. Further, during the etching process, the etching gas reacts chemically with the film layer to be etched 210, thereby removing a part of the thickness of the film layer to be etched 210. The top surface of the remaining film layer to be etched 210 is lower than the top surface of the hard mask layer 220, and the remaining film layer to be etched 210 and the shallow trench 200a form a shallow trench isolation structure.
[0047] Since the material of the patterned oxide layer 110 is the same as that of the film layer to be etched 210, the etching gas will also react chemically with the patterned oxide layer 110 to cause etching.
[0048] In this embodiment, the effective etching gas in the etching gas includes hydrogen fluoride, and the catalytic gas includes ammonia. A chemical reaction occurs between the etching gas and the patterned oxide layer 110 and the film layer to be etched 210, that is, hydrogen fluoride (HF), ammonia (NH 3 ) and silicon oxide (SiO 2)A chemical reaction occurs to form ammonium hexafluorosilicate (AFS), and the reaction formula is as follows:
[0049] NH 3 +HF+SiO 2 →(NH 4 ) 2 SiF 6 ;
[0050] In this embodiment, the process temperature of the dry etching process is 250°C to 300°C, such as 250°C, 260°C or 300°C. In an environment with a temperature of 250°C to 300°C, ammonium hexafluorosilicate will be decomposed into silicon tetrafluoride (SiF 4 ), ammonia (NH 3 ), hydrogen fluoride (HF) and other products, and the reaction formula is:
[0051] (NH 4 ) 2 SiF 6 →SiF 4+ 2NH 3 +2HF;
[0052] Furthermore, the generated gas volatiles can be evacuated by a vacuum pump, so as to discharge the gas volatiles from the process chamber of the dry etching machine. In addition, as can be seen from the above reaction formula, moisture is generated during the reaction. Therefore, in order to avoid the condensation of moisture on the surface of the product wafer 200, the water vapor can be evacuated together with the generated gas volatiles by a vacuum pump in an environment with a temperature of 250°C to 300°C, so as to ensure the dryness and cleanliness of the surface of the product wafer 200, and at the same time, the surface temperatures of the product wafer 200 and the mask wafer 100 can reach above the decomposition temperature of ammonium hexafluorosilicate rapidly.
[0053] In this embodiment, since the material of the mask wafer 100 is silicon, the effective etching gas includes hydrogen fluoride, and the catalytic gas includes ammonia, and silicon will not react with hydrogen fluoride and ammonia. Therefore, in an environment where hydrogen fluoride combines with ammonia, the mask wafer 100 will not react with hydrogen fluoride and ammonia, that is, the mask wafer 100 will not consume the etching gas. Specifically, in the area of the mask wafer 100 exposed in the patterned oxide layer 110, hydrogen fluoride reacts with ammonia to form ammonium fluoride (NH 4 F), and the specific reaction formula is as follows:
[0054] NH 3 +HF→NH 4 F;
[0055] Furthermore, ammonium fluoride can be decomposed into ammonia and hydrogen fluoride again after heating. Therefore, the blocking piece 100 exposed in the patterned oxide layer 110 has chemical stability in the dry etching process, while the patterned oxide layer 110 consumes the etching gas in the dry etching process. The two have a synergistic effect. During the execution of the dry etching process, by controlling the gas flow rate of the effective etching gas, i.e., hydrogen fluoride, on the surface of the product wafer 200, the etching amount of the film layer 210 to be etched on the product wafer 200 in the dry etching process can be controlled, thereby achieving the purpose of controlling the etching amount of the product wafer 200, and thus realizing sensitive and accurate control of the etching amount of the product wafer 200 and avoiding the problem of under-etching of the product wafer 200.
[0056] In this embodiment, when performing the dry etching process, the etching depth of the patterned oxide layer 110 is the same as the etching depth of the film layer 210 to be etched. The etching depth of the patterned oxide layer 110 and the etching depth of the film layer 210 to be etched can be 50 Å to 200 Å, such as 50 Å, 58 Å, 60 Å, 100 Å, 150 Å or 200 Å. Figure 10 It is a hot spot scan diagram of the surface of the product wafer in the dry etching method of the embodiment of the present invention. Compare Figure 10 and Figure 1 It can be seen that the average value (Avg) of the etching amount of the film layer 210 to be etched on the product wafer 200 is increased from 42 Å to 43 Å to 58 Å to 60 Å, indicating that the etching amount of the product wafer 200 with the patterned oxide layer 110 is effectively controlled. Therefore, the dry etching method provided in this embodiment is practical and effective and has good practicability.
[0057] Continue to refer to Figure 3 As shown, this embodiment further provides a blocking piece 100 for use in a dry etching process. A patterned oxide layer 110 is formed on the blocking piece 100. The patterned oxide layer 110 exposes a part of the surface of the blocking piece 100. The material of the patterned oxide layer 110 is the same as the material of the film layer 210 to be etched in the product wafer 200.
[0058] Figure 11 Schematic flow diagram of the manufacturing method of the blocking piece according to the embodiment of the present invention. As Figure 11 shown, this embodiment further provides a manufacturing method of a blocking piece, including:
[0059] Step S10: Provide a blocking piece;
[0060] Step S20: Form a patterned photoresist layer on the blocking piece;
[0061] Step S30: Using the patterned photoresist layer as a mask, perform an oxidation process on the blanking plate to form a patterned oxide layer. The material of the patterned oxide layer is the same as that of the film layer to be etched in the product wafer, and the material of the patterned oxide layer is different from that of the blanking plate;
[0062] Step S40: Remove the patterned photoresist layer to expose the surface of the blanking plate that is not covered by the patterned oxide layer; and,
[0063] Step S50: Perform a wet cleaning process on the blanking plate with the patterned oxide layer.
[0064] Figures 12 to 14 It is a schematic cross-sectional view of the structure formed in the method for manufacturing a blanking plate according to an embodiment of the present invention. The following will be combined with Figures 12 to 14 to describe in more detail the method for manufacturing a blanking plate according to an embodiment of the present invention.
[0065] First, referring to Figure 12 as shown, perform Step S10 to provide a blanking plate 100. The material of the blanking plate 100 is the same as that of the product wafer 200, and can be, for example, silicon.
[0066] Next, continue to refer to Figure 12 as shown, perform Step S20 to form a patterned photoresist layer 120 on the blanking plate 100. Specifically, first, spin-coat a photoresist layer on the blanking plate 100, and then perform exposure, development, and baking on the photoresist layer in sequence to form a patterned photoresist layer 120 that covers a part of the blanking plate 100.
[0067] Next, referring to Figure 13 as shown, perform Step S30 to perform an oxidation process on the blanking plate 100 using the patterned photoresist layer 120 as a mask to form a patterned oxide layer 110. The material of the patterned oxide layer 110 is the same as that of the film layer 210 to be etched in the product wafer 200. Among them, the materials of the patterned oxide layer 110 and the film layer 210 to be etched in the product wafer 200 are both silicon.
[0068] Specifically, the method for performing the oxidation process on the blanking plate 100 includes: using a dry stripping machine tool to perform the oxidation process, and the process gas for the oxidation process includes oxygen (O 2) During the oxidation process, the blocking layer with an uncovered portion of the non-patterned photoresist layer 120 in terms of thickness is oxidized, that is, the blocking piece 100 with an oxidized partial thickness is formed to obtain the patterned oxide layer 110. Among them, the thickness of the patterned oxide layer 110 can be 400 angstroms to 600 angstroms. Since the patterned oxide layer 110 has a pattern, during the dry etching process of the product wafer and the blocking piece, the etching amount of the patterned oxide layer 110 can be reduced, thereby reducing the consumption of etching gas in the dry etching process.
[0069] Next, referring to Figure 14 as shown, step S40 is performed to remove the patterned photoresist layer 120 and expose the surface of the blocking piece 100 that is not covered by the non-patterned oxide layer 110. In this embodiment, a dry stripping machine tool is used to remove the patterned photoresist layer 120, and the process gases for removing the patterned photoresist layer 120 include oxygen and nitrogen. That is to say, the patterned oxide layer 110 is formed and the patterned photoresist layer 120 is removed in the same process equipment. In this way, the process steps can be simplified and the process time can be saved. The process gases for removing the patterned photoresist layer 120 may include oxygen and nitrogen (N 2 ).
[0070] Next, as Figure 14 shown, step S50 is performed to perform a wet cleaning process on the blocking piece 100 with the patterned oxide layer 110. The by-products and polymer 130 on the blocking piece 100 are removed through the wet cleaning process to avoid contaminating the blocking piece 100. As Figure 14 shown, after removing the patterned photoresist layer, the surface of the blocking piece 100 has polymer 130 and by-products formed during the oxidation process, etc. These polymer 130 and by-products remain on the surface of the blocking piece 100, so the blocking piece will be contaminated. Therefore, in this example, the wet cleaning process is performed to remove the by-products and polymer 130 on the surface of the blocking piece 100.
[0071] In summary, in the mask sheet, its manufacturing method, and the dry etching method provided by the present invention, a patterned oxide layer is formed on the mask sheet. The patterned oxide layer exposes a part of the surface of the mask sheet. The material of the patterned oxide layer is the same as that of the film layer to be etched in the product sheet. During the etching process, the product sheet and the mask sheet are placed in the process chamber of a dry etching machine, and a dry etching process is performed to etch the film layer to be etched and the patterned oxide layer. Since the patterned oxide layer has a pattern, the etching amount can be reduced, thereby reducing the consumption of etching gas in the dry etching process. In addition, since the material of the patterned oxide layer is different from that of the mask sheet, in the dry etching process, the reaction of the etching gas with the patterned oxide layer and the mask sheet is different. The patterned oxide layer will consume the etching gas in the dry etching process, while the mask sheet has chemical stability in the dry etching process. Therefore, the synergistic effect of the two can be used to control the etching amount of the film layer to be etched on the product sheet in the dry etching process, thereby achieving the purpose of controlling the etching amount of the product sheet, and thus realizing sensitive and accurate control of the etching amount of the product sheet, and avoiding the problem of under-etching of the product sheet.
[0072] The above description is only a description of the preferred embodiments of the present invention, and does not limit the scope of the present invention in any way. Any changes and modifications made by those of ordinary skill in the art of the present invention based on the above disclosure are within the scope of protection of the claims.
Claims
1. A dry etching method, characterized in that, it includes: providing a mask plate and a product wafer, wherein the product wafer has a film layer to be etched, the mask plate has a patterned oxide layer, the patterned oxide layer exposes a part of the surface of the mask plate, the material of the patterned oxide layer is the same as the material of the film layer to be etched, and the material of the patterned oxide layer is different from the material of the mask plate; and, placing the product wafer and the mask plate in the process chamber of a dry etching machine tool, and performing a dry etching process to etch the film layer to be etched and the patterned oxide layer, wherein, in the dry etching process, the reaction of the etching gas with the patterned oxide layer and the mask plate is different.
2. The dry etching method according to claim 1, characterized in that, a hard mask layer is formed on the product wafer, a shallow trench is formed in the hard mask layer and the product wafer, the shallow trench extends from the top surface of the hard mask layer to the product wafer, the film layer to be etched fills the shallow trench and the top surface of the film layer to be etched is higher than the top surface of the product wafer.
3. The dry etching method according to claim 2, characterized in that, the patterned oxide layer has an opening, the opening exposes a part of the surface of the mask plate, and the width of the opening is greater than or equal to the width of the shallow trench.
4. The dry etching method according to claim 1, characterized in that, the thickness of the patterned oxide layer is 400 Å to 600 Å, and the thickness of the film layer to be etched is 2150 Å to 2350 Å; when performing the dry etching process, the etching depth of the patterned oxide layer is the same as the etching depth of the film layer to be etched, and the etching depth of the patterned oxide layer and the film layer to be etched is 50 Å to 200 Å.
5. The dry etching method according to claim 1, characterized in that, the materials of both the mask plate and the product wafer are silicon; the materials of both the patterned oxide layer and the film layer to be etched are silicon oxide.
6. The dry etching method according to claim 1, characterized in that, the process temperature of the dry etching process is 250 °C to 300 °C, and the etching gas includes hydrogen fluoride and ammonia.
7. A manufacturing method of a mask plate for a dry etching process, characterized in that, it includes: providing a mask plate; forming a patterned photoresist layer on the mask plate; using the patterned photoresist layer as a mask to oxidize the mask plate to form a patterned oxide layer, the material of the patterned oxide layer is the same as the material of the film layer to be etched in the product wafer, and the material of the patterned oxide layer is different from the material of the mask plate; removing the patterned photoresist layer to expose the surface of the mask plate not covered by the patterned oxide layer; and, performing a wet cleaning process on the mask plate with the patterned oxide layer.
8. The manufacturing method of the mask plate according to claim 7, characterized in that, The oxidation treatment is carried out by a dry stripping machine, and the process gas for the oxidation treatment includes oxygen; and, The patterned photoresist layer is removed by the dry stripping machine, and the process gas for removing the patterned photoresist layer includes oxygen and nitrogen.
9. The method for manufacturing a mask according to claim 7, characterized in that, The material of the mask and the material of the product wafer are both silicon; the material of the patterned oxide layer and the material of the film layer to be etched are both silicon oxide.
10. A mask for use in a dry etching process, characterized in that, A patterned oxide layer is formed on the mask, the patterned oxide layer exposes a part of the surface of the mask, the material of the patterned oxide layer is the same as the material of the film layer to be etched in the product wafer, and the material of the patterned oxide layer is different from the material of the mask.