Etching method and semiconductor device

Abstract

The invention discloses an etching method and a semiconductor device. The etching method comprises the steps of providing a to-be-etched structure; the structure to be etched comprises a semiconductor structure, a hard mask layer located on the surface of the semiconductor structure, an anti-reflection layer located on the hard mask layer and a patterned photoresist layer located on the anti-reflection layer, and the patterned photoresist layer is provided with a first window; etching the anti-reflection layer in a region corresponding to the first window to form a second window and obtain a patterned anti-reflection layer; etching gas adopted in the etching process of the anti-reflection layer comprises fluorine-containing gas, and the mass ratio of the fluorine-containing gas in the etching gas is 1: 5-1: 8; and removing the patterned photoresist layer. According to the method, the etching gas containing the fluorine-containing gas is adopted, so that the unexpected loss of the hard mask layer can be reduced, the generation amount of a polymer by-product which takes a hard mask layer material as one of reactants is reduced, and the polymer by-product can be conveniently and synchronously removed in the process of removing the patterned photoresist layer.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to an etching method and a semiconductor device. Background Art

[0002] In the semiconductor manufacturing process, when etching semiconductor structures such as dielectric layers, especially etching semiconductor structures with a large open ratio, most existing processes use a higher etching power to bombard a larger area of ​​the film layer to form a surface morphology; however, this process will result in a large number of etching by-products and will also cause a certain loss of the hard mask layer. During the etching process, the hard mask layer material bombarded out is easy to adhere to the side wall of the patterned photoresist layer, resulting in the formation of a polymer by-product hard shell on the side wall. In the subsequent process, the hard shell and the patterned photoresist layer attached to it are difficult to remove, which is not conducive to the morphological accuracy and preparation yield of the final semiconductor structure; and, after accumulation, more polymer by-products are also easy to adhere to the environment in which the etching process is located, which increases the difficulty and cost of maintaining the subsequent etching equipment. Summary of the invention

[0003] In order to solve the problems of the prior art, the embodiments of the present application provide an etching method and a semiconductor device. The technical solution is as follows:

[0004] In one aspect, the present application provides an etching method, comprising:

[0005] Providing a structure to be etched; the structure to be etched comprises a semiconductor structure, a hard mask layer located on a surface of the semiconductor structure, an anti-reflection layer located on the hard mask layer, and a patterned photoresist layer located on the anti-reflection layer, wherein the patterned photoresist layer has a first window;

[0006] The anti-reflection layer is etched in the area corresponding to the first window to form a second window, thereby obtaining a patterned anti-reflection layer; the etching gas used in the etching process of the anti-reflection layer includes a fluorine-containing gas, and the mass ratio of the fluorine-containing gas in the etching gas is 1:5 to 1:8;

[0007] The patterned photoresist layer is removed.

[0008] Furthermore, the etching gas satisfies at least one of the following characteristics:

[0009] The etching gas further comprises at least one of nitrogen, oxygen and argon;

[0010] The fluorine-containing gas includes at least one of carbon tetrafluoride and trifluoromethane.

[0011] Furthermore, the temperature condition used in the etching process is a gradually changing electrostatic adsorption temperature.

[0012] Furthermore, the electrostatic adsorption temperature is less than or equal to a preset temperature, and the preset temperature is 45°C to 55°C.

[0013] Further, the removing the patterned photoresist layer comprises:

[0014] The patterned photoresist layer is removed by a cleaning agent containing carbon tetrafluoride.

[0015] Furthermore, during the removal of the patterned photoresist layer, the flow rate of the carbon tetrafluoride is 40 sccm to 500 sccm.

[0016] Furthermore, the process used in the etching process of the anti-reflection layer is dry etching, and the power conditions of the dry etching include upper electrode power and lower electrode power;

[0017] The upper electrode power is 200W to 2000W;

[0018] The power of the lower electrode is 100W to 2500W.

[0019] Furthermore, the anti-reflection layer is placed in an ambient pressure of 50 mT to 400 mT during the etching process.

[0020] Furthermore, the etching groove ratio of the structure to be etched is greater than a preset groove ratio, and the preset groove ratio is 70% to 95%.

[0021] On the other hand, the present application also provides a semiconductor device, which is formed by a patterned anti-reflection layer prepared by the etching method as described in any one of the above items.

[0022] Implementing this application has the following beneficial effects:

[0023] 1. In the process of etching the anti-reflective layer of the structure to be etched, the present application adopts an etching gas containing fluorine gas, which increases the mass proportion of fluorine-containing gas in the etching gas, can reduce the etching selectivity for the hard mask layer material, reduce the undesired loss of the hard mask layer, thereby reducing the amount of polymer by-products generated with the hard mask layer material as one of the reactants and the amount of adhesion on the side wall surface of the patterned photoresist layer, making it easier for the polymer by-products to be removed simultaneously during the removal of the patterned photoresist layer, thereby improving the accuracy and reliability of the subsequent morphology control of the hard mask layer and the semiconductor structure based on the formed patterned anti-reflective layer, and is conducive to improving the preparation yield, morphology accuracy and performance of the finally formed semiconductor device.

[0024] 2. Using a gradually changing electrostatic adsorption temperature (ESC temperature) during the etching of the anti-reflective layer can increase the activity of the polymer by-products that have been produced during the etching process, making it easier for the polymer by-products to react with the cleaning agent to generate gas products that can be removed during the subsequent removal of the patterned photoresist layer, thereby improving the removal efficiency and effectiveness of the subsequent polymer by-product removal steps.

[0025] 3. Using a cleaning agent containing carbon tetrafluoride to remove the patterned photoresist layer can cause the fluorine ions ionized by carbon tetrafluoride to react with the hydrogen ions in the patterned photoresist layer material to form hydrofluoric acid (HF), which can effectively destroy the polymer byproduct hard shell attached to the side wall of the patterned photoresist layer, accelerate the reaction rate of the cleaning agent and the patterned photoresist layer material, and improve the efficiency, accuracy, effectiveness and reliability of removing the patterned photoresist layer.

[0026] 4. In the process of dry etching the anti-reflective layer, the present application adopts relatively low power conditions, which is beneficial to reduce the generation rate of polymer by-products and the breadth of their distribution range, and reduce the total amount of polymer by-products, so that they are easier to remove in the subsequent removal steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 A flowchart of an etching method provided in an embodiment of the present application;

[0029] Figure 2 This is a microscopic structural comparison diagram of the surface morphology after etching by a conventional etching method and the etching method provided in the embodiments of the present application.

[0030] Wherein, the accompanying drawings are marked as follows:

[0031] 1-hard mask layer, 2-anti-reflective layer, 21-second window, 22-patterned anti-reflective layer, 3-patterned photoresist layer, 31-first window. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0033] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe specific objects or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in a sequence other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or server that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0034] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there is no intervening element or layer. It should be understood that the depth direction of an element or layer is the direction perpendicular to the surface of the element or layer, and the direction of the cross section of an element or layer is the direction parallel to the surface of the element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present application, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part. When discussing a second element, component, region, layer or section, it does not necessarily mean that the first element, component, region, layer or section must be present.

[0035] In view of the problem in the prior art that the hard mask layer is easily damaged during the etching of the anti-reflection layer, so that the bombarded hard mask layer material is easy to generate polymer byproducts that adhere to the side wall surface of the patterned photoresist layer, resulting in a hard shell formed on the surface of the patterned photoresist layer that is difficult to remove, the embodiment of the present application provides an etching method and a semiconductor device, wherein the etching method first provides a structure to be etched, the structure to be etched includes a semiconductor structure, a hard mask layer located on the surface of the semiconductor structure, an anti-reflection layer located on the hard mask layer, and a patterned photoresist layer located on the anti-reflection layer, the patterned photoresist layer having a first window; then, the anti-reflection layer is etched in the area corresponding to the first window to form a second window to obtain a patterned anti-reflection layer, and an etching gas with a mass ratio of fluorine-containing gas of 1:5 to 1:8 is used in the etching process; then, the patterned photoresist layer is removed to facilitate subsequent semiconductor processes.

[0036] In the process of etching the anti-reflective layer, most of the time the hard mask layer will cause certain losses. The etching gas containing fluorine gas is used to etch the anti-reflective layer, which can reduce the etching selectivity for the mask layer material. Correspondingly, the etching selectivity for the anti-reflective layer material to be etched is improved. When etching the hard mask layer, the etching rate and loss of the hard mask layer material can be reduced, which is beneficial to inhibit the side reaction with the hard mask layer material as one of the reactants, reduce the amount of polymer by-products generated and the amount of their attachment on the side wall of the patterned photoresist layer, facilitate removal in subsequent steps and reduce the adverse effects on the patterned photoresist layer removal step, with high etching efficiency, good etching accuracy and good reliability.

[0037] The following is combined with Figure 1-2 The etching method of the embodiment of the present application is described in detail.

[0038] See also Figure 1 , providing a structure to be etched.

[0039] Among them, the structure to be etched includes a semiconductor structure, a hard mask layer 1 located on the surface of the semiconductor structure, an anti-reflection layer 2 located on the hard mask layer 1 and a patterned photoresist layer 3 located on the anti-reflection layer 2. The patterned photoresist layer 3 has a first window 31, and the first window 31 is used to align and etch away the anti-reflection layer 2 area below in a subsequent step, and to etch through the hard mask layer 1 in the corresponding area in a subsequent semiconductor process until it is etched into the semiconductor structure, forming a patterned morphology in the semiconductor structure.

[0040] The etching method is particularly applicable to the structure to be etched or the patterned photoresist layer 3 with relatively large surface etching grooves, that is, when the area of ​​the first window 31 in the whole layer structure composed of the first window 31 and the patterned photoresist layer 3 accounts for a relatively large proportion. For example, it is applicable to the process of forming a fin field effect transistor (FinFET) fin from a semiconductor structure. The grooves are relatively large and the coverage rate of the surface patterned photoresist layer 3 is low. In the subsequent process flow, the area etched away is relatively large, resulting in more by-products being generated, which are difficult to remove in the subsequent steps and will also affect the removal of the patterned photoresist layer 3 and the subsequent semiconductor process. The etching method is used to reduce the loss of the hard mask layer 1 and reduce the difficulty of removing the polymer by-products.

[0041] Specifically, in some exemplary embodiments, the etching slot ratio of the structure to be etched is greater than the preset slot ratio, and the preset slot ratio is 70% to 95%; it can be understood that the preset slot ratio can be any point value between 70% and 95%; illustratively, the preset slot ratio can be 70%, 75%, 80%, 82.5%, 85%, 90%, 95%, etc.; in this way, the area of ​​the structure to be etched that needs to be etched accounts for a large proportion, and more by-products are generated during the etching process. A large number of by-products are attached to the side of the patterned photoresist layer 3. It is difficult to remove. The etching method can be applied to the structure to be etched with a relatively large etching groove. Compared with the traditional process, it greatly reduces the amount of by-products generated and attached, and improves the removal efficiency and removal effect of the by-products on the patterned photoresist layer 3; for example, in some specific embodiments, the preset groove ratio is 90%, that is, the etching groove ratio of the structure to be etched is greater than 90%. The etching method is particularly suitable for the structure to be etched with an etching groove ratio greater than 90%, which effectively improves the removal efficiency and removal effect of the patterned photoresist layer 3 and the by-products attached to its surface.

[0042] Then, if Figure 1 As shown, the anti-reflection layer is etched in the area corresponding to the first window to form a second window, thereby obtaining a patterned anti-reflection layer.

[0043] This step is used to form a second window 21 penetrating the anti-reflection layer 2 in the area corresponding to the first window 31 to form a patterned anti-reflection layer 22, so as to facilitate the processing of the hard mask layer 1 exposed by the second window 21 and the semiconductor structure covered thereunder in the subsequent semiconductor process, thereby improving the morphology accuracy of the subsequent processing; and in this step, it is inevitable that a certain thickness of the hard mask layer 1 will be lost, but it is not easy to completely etch through the hard mask layer 1, so that the hard mask layer 1 can still play a certain protective role on the semiconductor structure.

[0044] Among them, the etching gas used in the etching process of the anti-reflective layer 2 includes a fluorine-containing gas, and the mass proportion of the fluorine-containing gas in the etching gas is negatively correlated with the etching selectivity of the hard mask layer 1, that is, the more the mass proportion of the fluorine-containing gas in the etching gas, the lower the etching selectivity for the hard mask layer 1, and the less likely the hard mask layer 1 is to be etched; the etching selectivity for the hard mask layer 1 material is reduced, which can reduce the generation of polymer by-products during the etching process and reduce the loss of hard mask layer 1 material. Then, the reactants of the side reaction are reduced, and the amount of polymer by-products generated and the amount of their attachment on the surface of the patterned photoresist layer 3 are also reduced accordingly, reducing the difficulty of subsequent removal of the polymer by-products.

[0045] Moreover, the etching gas is mainly used to etch the anti-reflective layer 2, reducing the etching selectivity for the mask layer material, and correspondingly improving the etching selectivity for the anti-reflective layer 2 material to be etched; in some exemplary embodiments, the target selectivity r of the etching step is the ratio of the etching rate of the anti-reflective coating to the etching rate of the hard mask layer 1, and the target selectivity is positively correlated with the mass proportion of the fluorine-containing gas in the etching gas, that is, the target selectivity increases with the increase of the mass proportion of the fluorine-containing gas in the etching gas, that is, by introducing the fluorine-containing gas and increasing the mass proportion of the fluorine-containing gas, the etching rate of the anti-reflective coating is improved, and the etching rate of the hard mask layer 1 is reduced, thereby achieving the purpose of reducing the amount of polymer by-products generated, which is beneficial to improving the convenience of subsequent removal of the polymer by-products.

[0046] Specifically, in some exemplary embodiments, the fluorine-containing gas includes at least one of carbon tetrafluoride and trifluoromethane; exemplarily, the fluorine-containing gas may include carbon tetrafluoride, or the fluorine-containing gas includes trifluoromethane, or the fluorine-containing gas includes a mixed gas of carbon tetrafluoride and trifluoromethane, which can effectively reduce the etching selectivity for the hard mask layer 1, reduce the loss of the hard mask layer 1, and thereby reduce the generation and adhesion of polymer by-products.

[0047] Specifically, the etching gas also includes at least one of nitrogen, oxygen and argon, which can effectively react with the material of the anti-reflection layer 2 to remove the anti-reflection layer 2, with high etching efficiency and good etching precision.

[0048] Specifically, the mass ratio of fluorine-containing gas in the etching gas is 1:5 to 1:8; it can be understood that the mass ratio of fluorine-containing gas in the etching gas can be any point value in the range of 1:5 to 1:8; illustratively, the mass ratio of fluorine-containing gas in the etching gas can be 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, etc.; in this way, the fluorine-containing gas in the etching process is increased, which can reduce the loss of hard mask layer 1 material, thereby reducing the generation and adhesion of polymer by-products, and reducing the difficulty of subsequent removal; in addition, it should be noted that the fluorine-containing gas is also easily dissociated into active ion groups during the etching process, which can react with the polysilicon of the anti-reflection layer 2 to generate water, carbon dioxide and fluorine-containing by-products. Then, the mass ratio of the fluorine-containing gas in the etching gas is controlled within this range, which can not only effectively etch the anti-reflection layer 2, but also reduce the generation of various different by-products such as fluorine-containing by-products and polymer by-products.

[0049] Specifically, the temperature condition used in the etching process is a gradually changing electrostatic adsorption temperature (ESC temperature). The gradually changing electrostatic adsorption temperature can enhance the activity of the polymer by-products that have been generated, so that the polymer by-products are more likely to react more strongly with the fluorine-containing gas during the etching process, and are easy to further generate gas products and be taken away, thereby reducing the difficulty of removal in the subsequent cleaning process; and, it can also increase the intensity of the reaction of the polymer by-products with carbon tetrafluoride in the subsequent cleaning process, and are also easy to be extracted and removed after the gas products are generated, thereby further improving the removal efficiency and effectiveness of the subsequent cleaning process.

[0050] Among them, the electrostatic adsorption temperature is positively correlated with the activity of the polymer by-products, that is, the higher the electrostatic adsorption temperature, the higher the activity of the polymer by-products, which is used to make the reaction between the fluorine-containing gas in the subsequent cleaning agent and the polymer by-products more intense, and it is easy to generate gas products to be taken away, thereby improving the convenience and accuracy of the subsequent removal of the patterned photoresist layer 3.

[0051] In some exemplary embodiments, the etching process can be heated to a target electrostatic adsorption temperature within a preset time. There can be a single preset time to heat up to the target electrostatic adsorption temperature and then maintain the temperature stable for etching. There can also be multiple preset times. The target electrostatic adsorption temperature of each preset time can be the same or different. Specifically, specific temperature parameters can be set in the etching equipment to meet a variety of different etching requirements and prepare a variety of semiconductor devices with different functions. It has a wide range of applications.

[0052] Specifically, the electrostatic adsorption temperature is less than or equal to the preset temperature, and the preset temperature is 45°C to 55°C; it can be understood that the preset temperature can be any point value between 45°C and 55°C; illustratively, the preset temperature can be 45°C, 47.5°C, 48°C, 50°C, 52.5°C, 55°C, etc.; in this way, the activity of the polymer by-products can be effectively improved, and the convenience and reliability of removing the polymer by-products can be improved; for example, in some specific embodiments, the preset temperature is 50°C, that is, the electrostatic adsorption temperature is less than or equal to 50°C, and during the etching process, the electrostatic adsorption temperature can be gradually increased to 50°C.

[0053] Specifically, the process used in the etching process of the anti-reflection layer 2 is dry etching, and the plasma generated by the etching gas is used to physically and chemically react with the anti-reflection layer 2 material exposed to the plasma through the first window 31 opened by photolithography; wherein the power condition of the dry etching includes the upper electrode power and the lower electrode power, and the power condition of the dry etching is determined based on the etching rate of the hard mask layer 1 material, and the power condition is positively correlated with the etching rate of the hard mask layer 1 material; by controlling the power during the etching process to maintain a relatively low state, the etching rate of the hard mask layer 1 material can be reduced, and the amount of polymer by-products produced per unit time can be effectively reduced. Then, after the etching step of the anti-reflection layer 2 is completed, the by-products attached to the side wall surface of the patterned photoresist layer 3 can be effectively reduced, which is convenient for the subsequent removal of the by-products and the patterned photoresist layer 3.

[0054] Specifically, the upper electrode power is 200W to 2000W; it can be understood that the upper electrode power can be any point value between 200W and 2000W; illustratively, the upper electrode power can be 200W, 500W, 1000W, 1200W, 1500W, 1750W, 2000W, etc.

[0055] Specifically, the lower electrode power is 100W to 2500W; it can be understood that the lower electrode power can be any point value between 100W and 2500W; illustratively, the lower electrode power can be 100W, 200W, 500W, 1000W, 1200W, 1500W, 2000W, 2250W, 2500W, etc.

[0056] In this way, the dry etching process adopts low-frequency power, which can reduce the etching rate of the hard mask layer 1 material, reduce the generation rate of polymer by-products, and reduce the by-products attached to the surface of the patterned photoresist layer 3, which are easier to remove; in addition, in the dry etching process, most of the structures to be etched are placed in a closed cavity bombarded by plasma to maintain the stability of various process conditions of the dry etching process. The bombardment process under low-frequency power can reduce the polymer by-products inside the closed cavity, facilitate the subsequent cleaning and maintenance of the closed cavity, reduce maintenance costs, and also reduce the loss of components in the closed cavity, including the focusing ring for confining plasma, the gas distribution plate for achieving uniform distribution of etching gas, and the electron adsorption plate for fixing the structure to be etched, thereby extending the life of the components in the closed cavity.

[0057] Specifically, the ambient air pressure of the anti-reflection layer 2 during the etching process is 50mT~400mT; it can be understood that the ambient air pressure is the air pressure in the closed cavity, and the ambient air pressure can be any point value between 50mT~400mT; illustratively, the ambient air pressure can be 50mT, 60mT, 75mT, 80mT, 100mT, 150mT, 200mT, 300mT, 400mT, etc., which is conducive to the gas circulation in the closed cavity to extract the generated polymer by-products, further reduce the amount of polymer by-products attached to the side wall surface of the patterned photoresist layer 3, and reduce the difficulty of removing the subsequent polymer by-product hard shell.

[0058] In this way, the generation of polymer by-products is greatly reduced during the etching process of the anti-reflection layer 2, and the polymer by-products that have been generated are easier to remove. The polymer by-products in the closed cavity can also be reduced simultaneously, which facilitates the subsequent cleaning and maintenance of the closed cavity and reduces maintenance costs; at the same time, the loss of various equipment components in the closed cavity is reduced, and the life of the components in the closed cavity is extended to a certain extent.

[0059] Then, if Figure 1 As shown, the patterned photoresist layer is removed.

[0060] Specifically, removing the patterned photoresist layer includes:

[0061] The patterned photoresist layer is removed by a cleaning agent containing carbon tetrafluoride.

[0062] During the cleaning process, carbon tetrafluoride can ionize fluorine ions and react with hydrogen ions in the patterned photoresist layer 3 to generate hydrofluoric acid. The hydrofluoric acid can react with the polymer by-products to effectively destroy the polymer by-product crust attached to the side walls of the patterned photoresist layer 3, thereby facilitating the effective removal of the patterned photoresist layer 3 material.

[0063] Specifically, during the removal of the patterned photoresist layer 3, the flow rate of carbon tetrafluoride is 40sccm to 500sccm; it can be understood that the flow rate of carbon tetrafluoride can be any point value between 40sccm and 500sccm; illustratively, the flow rate of carbon tetrafluoride can be 40sccm, 50sccm, 100sccm, 200sccm, 300sccm, 400sccm, 500sccm, etc.; at this carbon tetrafluoride flow rate, the polymer byproduct hard shell attached to the side wall of the patterned photoresist layer 3 can be effectively destroyed, preventing adverse effects on the removal of the patterned photoresist layer 3, and improving the removal accuracy and removal stability of the patterned photoresist layer 3.

[0064] Specifically, the cleaning agent also includes oxygen, which can react with the patterned photoresist layer 3 material to achieve the removal of the patterned photoresist layer 3, thereby accelerating the reaction rate with the patterned photoresist layer 3 material; the flow rate of oxygen in the cleaning agent is 16ccm~500sccm; it can be understood that the flow rate of oxygen in the cleaning agent can be any point value between 16ccm and 500sccm; illustratively, the flow rate of oxygen in the cleaning agent can be 16ccm, 20ccm, 50ccm, 100ccm, 200ccm, 300ccm, 400ccm, 500sccm, etc.; within the oxygen flow rate range, in combination with carbon tetrafluoride, the patterned photoresist layer 3 can be removed in the same process step of destroying the hard shell of the surface polymer byproduct, thereby improving the removal effectiveness, removal accuracy and removal reliability of the patterned photoresist layer 3, which is beneficial to the morphological accuracy and performance of semiconductor devices formed in subsequent semiconductor processes.

[0065] In addition, the etching method can be applied to a variety of photoresist layer materials, a variety of anti-reflection layer 2 materials and a variety of hard mask layer 1 materials, which are not specifically limited in the present application; illustratively, the photoresist layer (PR), the anti-reflection layer 2 formed by silicon oxynitride (SiON) and the hard mask layer 1 formed by titanium nitride (TiN) are easily etched to titanium nitride in the traditional etching process, resulting in the loss of the hard mask layer 1, and the bombarded Ti adheres to the side wall of the photoresist layer to form a polymer hard shell, which is difficult to remove and makes it difficult to remove the photoresist layer, affecting the preparation yield and preparation accuracy of the subsequent semiconductor process.

[0066] And as Figure 2As shown, compared with the surface morphology a) formed by etching in the traditional process, the etching method provided by the embodiment of the present application increases the proportion of fluorine-containing gas in the etching gas used in the silicon oxynitride etching process, reduces the etching power, and then uses a cleaning agent containing carbon tetrafluoride for removal under the condition of a gradually changing ESC temperature. The various steps work together to effectively reduce the generation rate of polymer by-products, while reducing the loss of titanium nitride to reduce the generation of polymer by-products, and improving the activity of the generated polymer by-products to facilitate their removal during the cleaning process. They can also be easily destroyed by carbon tetrafluoride during the removal process to accelerate the removal of the polymer by-products and the photoresist layer. In this way, the difficulty of removing the polymer by-products and the photoresist layer is fully reduced, so that the subsequent semiconductor process can be carried out accurately and stably, and the morphology accuracy and performance stability of the semiconductor device finally formed are improved.

[0067] The embodiment of the present application also provides a semiconductor device, which is formed based on the patterned anti-reflection layer obtained by the etching method as described above, which is beneficial to improving the preparation yield of the semiconductor device and improving the structural accuracy and performance of the semiconductor device.

[0068] An embodiment of the present application also provides an electronic device, which includes any one of the semiconductor devices or any one of the semiconductor devices described in the embodiments of the present application. The electronic device can be any electronic product or device such as a mobile phone, a tablet computer, a laptop computer, a netbook, a game console, a television, a VCD, a DVD, a navigator, a camera, a camcorder, a voice recorder, an MP3, an MP4, a PSP, etc., and can also be an intermediate product having the semiconductor device, for example: a device motherboard having the semiconductor device, etc.; the electronic device adopts the semiconductor device, which correspondingly improves the working performance of the electronic device.

[0069] Although the present application is disclosed as above, the present application is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, the protection scope of the present application shall be subject to the scope defined by the claims.

Claims

1. An etching method, characterized in that: include: Providing a structure to be etched; the structure to be etched comprises a semiconductor structure, a hard mask layer located on a surface of the semiconductor structure, an anti-reflection layer located on the hard mask layer, and a patterned photoresist layer located on the anti-reflection layer, wherein the patterned photoresist layer has a first window; The anti-reflection layer is etched in the area corresponding to the first window to form a second window, thereby obtaining a patterned anti-reflection layer; the etching gas used in the etching process of the anti-reflection layer includes a fluorine-containing gas, and the mass ratio of the fluorine-containing gas in the etching gas is 1:5 to 1:8; The patterned photoresist layer is removed.

2. The etching method according to claim 1, characterized in that: The etching gas satisfies at least one of the following characteristics: The etching gas further comprises at least one of nitrogen, oxygen and argon; The fluorine-containing gas includes at least one of carbon tetrafluoride and trifluoromethane.

3. The etching method according to claim 1, characterized in that: The temperature condition used in the etching process is a gradually changing electrostatic adsorption temperature.

4. The etching method according to claim 3, characterized in that: The electrostatic adsorption temperature is less than or equal to a preset temperature, and the preset temperature is 45°C to 55°C.

5. The etching method according to claim 1, characterized in that: The removing the patterned photoresist layer comprises: The patterned photoresist layer is removed by a cleaning agent containing carbon tetrafluoride.

6. The etching method according to claim 5, characterized in that: During the removal of the patterned photoresist layer, the flow rate of the carbon tetrafluoride is 40 sccm to 500 sccm.

7. The etching method according to any one of claims 1 to 6, characterized in that: The process used in the etching process of the anti-reflection layer is dry etching, and the power conditions of the dry etching include upper electrode power and lower electrode power; The upper electrode power is 200W to 2000W; The power of the lower electrode is 100W to 2500W.

8. The etching method according to any one of claims 1 to 6, characterized in that: The ambient pressure of the anti-reflection layer during the etching process is 50 mT to 400 mT.

9. The etching method according to any one of claims 1 to 6, characterized in that: The etching groove ratio of the structure to be etched is greater than a preset groove ratio, and the preset groove ratio is 70% to 95%.

10. A semiconductor device, characterized in that: The patterned anti-reflection layer is formed based on the etching method according to any one of claims 1 to 9.

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