An etching method and semiconductor device

Abstract

The application discloses an etching method and a semiconductor device, including providing 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; etching the anti-reflection layer in the region corresponding to the first window to form a second window, obtaining a patterned anti-reflection layer; the etching gas used in the etching process of the anti-reflection layer includes a fluorine-containing gas, the mass ratio of the fluorine-containing gas in the etching gas is 1:5-1:8; and the patterned photoresist layer is removed. The application uses the etching gas with the fluorine-containing gas, can reduce the undesired loss of the hard mask layer, thereby reducing the generation amount of the polymer by-product taking the hard mask layer material as one of the reactants, and facilitating the synchronous removal of the polymer by-product in the process of removing the patterned photoresist layer.

Description

Technical Field

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

[0002] In semiconductor manufacturing processes, when etching semiconductor structures such as dielectric layers, especially those with a large open ratio, existing processes mostly employ high etching power to bombard a large area of ​​the film layer to form the surface morphology. However, this process results in a large number of etching byproducts and also causes some loss of the hard mask layer. During the etching process, the hard mask material bombarded tends to adhere to the sidewalls of the patterned photoresist layer, causing the formation of polymer byproduct hard shells on the sidewalls. In subsequent processes, these hard shells and the attached patterned photoresist layer are difficult to remove, which is detrimental to the morphological accuracy and fabrication yield of the final semiconductor structure. Furthermore, over time, more polymer byproducts tend to adhere to the environment in which the etching process takes place, increasing the difficulty and cost of maintaining the etching equipment in the later stages. Summary of the Invention

[0003] To address the problems of existing technologies, this application provides an etching method and a semiconductor device. The technical solution is as follows:

[0004] On the one hand, this application provides an etching method, including:

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

[0006] The anti-reflective layer is etched in the area corresponding to the first window to form a second window, thereby obtaining a patterned anti-reflective layer. The etching gas used in the etching process of the anti-reflective 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] Remove the patterned photoresist layer.

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

[0009] The etching gas also includes 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 conditions used in the etching process are gradually varying electrostatic adsorption temperatures.

[0012] Furthermore, the electrostatic adsorption temperature is less than or equal to a preset temperature, which is 45℃~55℃.

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

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

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

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

[0019] Furthermore, the ambient air pressure during the etching process of the anti-reflective layer is 50mT to 400mT.

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

[0021] On the other hand, this application also provides a semiconductor device formed based on a patterned anti-reflective layer obtained by the etching method described in any of the preceding claims.

[0022] Implementing this application will have the following beneficial effects:

[0023] 1. In the etching process of the anti-reflection layer of the structure to be etched, this application uses an etching gas containing fluorine gas, which increases the mass ratio of fluorine gas in the etching gas. This reduces the etching selectivity for the hard mask layer material and the undesirable loss of the hard mask layer. Consequently, it reduces the amount of polymer byproducts generated when the hard mask layer material is used as one of the reactants and their adhesion to the sidewall surface of the patterned photoresist layer. This facilitates the simultaneous removal of polymer byproducts during the removal of the patterned photoresist layer, improving the accuracy and reliability of subsequent morphology control of the hard mask layer and semiconductor structure based on the formed patterned anti-reflection layer. This is beneficial to improving the fabrication yield, morphology accuracy, and performance of the final semiconductor device.

[0024] 2. Using a gradually varying electrostatic adsorption temperature (ESC temperature) during the etching process of the antireflective layer can increase the activity of polymer byproducts generated during the etching process. This makes it easier for the polymer byproducts to react with the cleaning agent to generate gaseous products during the subsequent removal of the patterned photoresist layer, thereby improving the removal efficiency and effectiveness of the polymer byproducts in the removal steps.

[0025] 3. Using a cleaning agent containing carbon tetrafluoride to remove the patterned photoresist layer can effectively destroy the polymer byproduct hard shell attached to the sidewalls of the patterned photoresist layer by reacting the fluoride ions ionized from the carbon tetrafluoride with the hydrogen ions in the patterned photoresist layer material to form hydrofluoric acid (HF). This accelerates the reaction rate between the cleaning agent and the patterned photoresist layer material, improving the efficiency, accuracy, effectiveness, and reliability of the patterned photoresist layer removal.

[0026] 4. In the process of dry etching of the anti-reflection layer, this application adopts relatively low power conditions, which helps to reduce the generation rate and distribution range of polymer by-products, reduce the total amount of polymer by-products, and make them easier to remove in subsequent removal steps. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

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

[0029] Figure 2 This is a microscopic comparison of the surface morphology after etching using conventional etching methods and the etching method provided in the embodiments of this application.

[0030] The attached figures are labeled 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 Implementation

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0033] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe specific objects or a sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or server that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such 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 may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that the depth direction of an element or layer is perpendicular to the surface of the element or layer, and the cross-sectional direction of an element or layer is parallel to the surface of the element or layer. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion. When discussing a second element, component, region, layer, or portion, it does not imply that the application necessarily contains a first element, component, region, layer, or portion.

[0035] To address the problem in existing technologies where the etching process of the anti-reflective layer easily damages the hard mask layer, causing the bombarded hard mask layer material to easily generate polymer byproducts that adhere to the sidewall surface of the patterned photoresist layer, resulting in a hard shell on the surface of the patterned photoresist layer that is difficult to remove, this application provides an etching method and a semiconductor device. The etching method first provides a structure to be etched, which includes a semiconductor structure, a hard mask layer on the surface of the semiconductor structure, an anti-reflective layer on the hard mask layer, and a patterned photoresist layer on the anti-reflective layer. The patterned photoresist layer has a first window. Then, the anti-reflective layer is etched in the area corresponding to the first window to form a second window, resulting in a patterned anti-reflective layer. The etching process uses an etching gas containing fluorine gas at a mass ratio of 1:5 to 1:8. Finally, the patterned photoresist layer is removed to facilitate subsequent semiconductor processing.

[0036] During the etching process of the antireflective layer, the hard mask layer is often damaged to some extent. Using an etching gas containing fluorine to etch the antireflective layer can reduce the etching selectivity of the mask layer material and correspondingly increase the etching selectivity of the antireflective layer material to be etched. When etching the hard mask layer, the etching rate and loss of the hard mask layer material can be reduced, which helps to suppress side reactions in which the hard mask layer material is one of the reactants, reduce the amount of polymer by-products generated and their adhesion to the sidewalls of the patterned photoresist layer, facilitate their removal in subsequent steps, and reduce the adverse effects on the patterned photoresist layer removal step. This results in high etching efficiency, good etching accuracy, and high reliability.

[0037] The following is in conjunction with the appendix Figure 1-2 The etching method of the embodiments of this application will be described in detail.

[0038] See Figure 1 Provides the structure to be etched.

[0039] The structure to be etched includes a semiconductor structure, a hard mask layer 1 on the surface of the semiconductor structure, an anti-reflection layer 2 on the hard mask layer 1, and a patterned photoresist layer 3 on the anti-reflection layer 2. The patterned photoresist layer 3 has a first window 31, which is used to align and etch away the area of ​​the underlying anti-reflection layer 2 in subsequent steps, and to etch through the hard mask layer 1 of the corresponding area in subsequent semiconductor processes, until it is etched into the semiconductor structure, resulting in a patterned morphology in the semiconductor structure.

[0040] This etching method is particularly suitable for structures with large etched grooves or patterned photoresist layers 3, where the area of ​​the first window 31 and the patterned photoresist layer 3 constitutes a relatively large proportion of the overall structure. For example, in the process of forming fins of a semiconductor structure into a FinFET, the large grooves result in a low coverage of the patterned photoresist layer 3, leading to a larger area being etched away in subsequent processes. This results in more byproducts that are difficult to remove in later steps, affecting the removal of the patterned photoresist layer 3 and subsequent semiconductor processes. This etching method reduces the wear of the hard mask layer 1 and lowers the difficulty of removing polymer byproducts.

[0041] Specifically, in some exemplary embodiments, the etching trench ratio of the structure to be etched is greater than a preset trench ratio, which is 70% to 95%. Understandably, the preset trench ratio can be any value within the range of 70% to 95%. For example, the preset trench ratio can be 70%, 75%, 80%, 82.5%, 85%, 90%, 95%, etc. Thus, the area to be etched is large, resulting in more byproducts generated during the etching process, and a large number of byproducts adhere to the sides of the patterned photoresist layer 3. Difficult to remove, this etching method is applicable to structures with relatively large etching grooves. Compared with traditional processes, it greatly reduces the amount of by-products generated and attached, and improves the removal efficiency and effect of 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%. This etching method is particularly suitable for structures with an etching groove ratio greater than 90%, effectively improving the removal efficiency and effect of by-products attached to the patterned photoresist layer 3 and its surface.

[0042] Next, as Figure 1 As shown, the anti-reflective layer is etched in the area corresponding to the first window to form the second window, resulting in a patterned anti-reflective layer.

[0043] This step is used to form a second window 21 that penetrates the anti-reflection layer 2 in the area corresponding to the first window 31, so as to form a patterned anti-reflection layer 22. This facilitates the processing of the hard mask layer 1 exposed by the second window 21 and the semiconductor structure covered below it in subsequent semiconductor processes, thereby improving the topographic accuracy of subsequent processing. In this step, a certain thickness loss of the hard mask layer 1 is inevitable, 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 for the semiconductor structure.

[0044] In the etching process of the anti-reflection layer 2, the etching gas used includes fluorine-containing gas. The mass ratio of fluorine-containing gas in the etching gas is negatively correlated with the etching selectivity of the hard mask layer 1. That is, the higher the mass ratio of fluorine-containing gas in the etching gas, the lower the etching selectivity of the hard mask layer 1, and the less likely the hard mask layer 1 is to be etched. The reduced etching selectivity of the hard mask layer 1 material can reduce the generation of polymer by-products during the etching process and reduce the loss of the hard mask layer 1 material. As a result, the reactants of the side reactions are reduced, the amount of polymer by-products generated and their adhesion on the surface of the patterned photoresist layer 3 are also reduced, which reduces the difficulty of subsequent removal of polymer by-products.

[0045] Furthermore, the etching gas is mainly used to etch the antireflective layer 2, reducing the etching selectivity for the mask layer material and correspondingly increasing the etching selectivity for the antireflective layer 2 material to be etched. In some exemplary embodiments, the target selectivity r of this etching step is the ratio between the etching rate of the antireflective coating and the etching rate of the hard mask layer 1. The target selectivity is positively correlated with the mass ratio of fluorine-containing gas in the etching gas. That is, as the mass ratio of fluorine-containing gas in the etching gas increases, the target selectivity increases. In other words, by introducing fluorine-containing gas, the mass ratio of fluorine-containing gas is increased, thereby increasing the etching rate of the antireflective coating and reducing the etching rate of the hard mask layer 1, thereby reducing the amount of polymer by-products generated and improving the convenience of subsequent removal of polymer by-products.

[0046] Specifically, in some exemplary embodiments, the fluorinated gas includes at least one of carbon tetrafluoride and trifluoromethane; exemplaryly, the fluorinated gas may include carbon tetrafluoride, or the fluorinated gas may include trifluoromethane, or the fluorinated gas may include a mixture 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 amount of polymer by-products generated and attached.

[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-reflective layer 2 to remove the anti-reflective layer 2, resulting in 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; understandably, the mass ratio of fluorine-containing gas in the etching gas can be any value within the range of 1:5 to 1:8; for example, 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.; thus, increasing the amount of fluorine-containing gas in the etching process can reduce the loss of the hard mask layer 1 material, thereby reducing the amount of polymer by-products generated and attached, and reducing the difficulty of their subsequent removal; in addition, it should be noted that fluorine-containing gas is also easily dissociated into active ionic groups during the etching process, which can react with the polycrystalline silicon of the anti-reflection layer 2 to generate water, carbon dioxide, and fluorine-containing by-products. Therefore, controlling the mass ratio of fluorine-containing gas in the etching gas within this range can effectively etch the anti-reflection layer 2 and reduce the generation of various by-products such as fluorine-containing by-products and polymer by-products.

[0049] Specifically, the temperature conditions used in the etching process are gradually changing electrostatic adsorption temperatures (ESC temperatures). These gradually changing ESC temperatures can enhance the activity of the polymer byproducts that have already been generated, making it easier for the polymer byproducts to react more strongly with fluorine-containing gases during the etching process. This facilitates the formation of further gaseous products that are carried away, reducing the difficulty of removal during subsequent cleaning. Furthermore, it can also increase the intensity of the reaction between the polymer byproducts and carbon tetrafluoride during subsequent cleaning, making it easier to extract and remove the gaseous products after they are formed, further improving the removal efficiency and effectiveness of subsequent cleaning processes.

[0050] Among them, the electrostatic adsorption temperature is positively correlated with the activity of polymer by-products. That is, the higher the electrostatic adsorption temperature, the higher the activity of polymer by-products. This makes the reaction between the fluorine-containing gas in the subsequent cleaning agent and the polymer by-products more intense, making it easier to generate gaseous products that are carried away, thereby improving the convenience and accuracy of the subsequent three-step removal of the patterned photoresist layer.

[0051] In some exemplary embodiments, the etching process can be carried out by heating to the target electrostatic adsorption temperature within a preset time. It can be carried out by heating to the target electrostatic adsorption temperature in a single preset time and then maintaining the temperature stable for etching, or it can be carried out by multiple preset time periods. The target electrostatic adsorption temperature of each preset time period can be the same or different. Specifically, specific temperature parameters can be set in the etching equipment to meet various different etching requirements and to prepare various semiconductor devices with different functions, with a wide range of applications.

[0052] Specifically, the electrostatic adsorption temperature is less than or equal to a preset temperature, which is 45℃ to 55℃. Understandably, the preset temperature can be any value within the range of 45℃ to 55℃. For example, the preset temperature can be 45℃, 47.5℃, 48℃, 50℃, 52.5℃, 55℃, etc. In this way, the activity of polymer by-products can be effectively improved, and the convenience and reliability of removing polymer by-products can be enhanced. For example, in some specific embodiments, the preset temperature is 50℃, that is, the electrostatic adsorption temperature is less than or equal to 50℃, and the electrostatic adsorption temperature can be gradually increased to 50℃ during the etching process.

[0053] Specifically, the etching process of the anti-reflection layer 2 employs dry etching, utilizing plasma generated by etching gas to conduct physical and chemical reactions with the anti-reflection layer 2 material exposed in the plasma through the first window 31 opened by photolithography. The power conditions of this dry etching include the upper electrode power and the lower electrode power, which are determined based on the etching rate of the hard mask layer 1 material. This 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 remain at a relatively low level, the etching rate of the hard mask layer 1 material can be reduced, effectively reducing the amount of polymer by-products generated per unit time. Therefore, after the etching step of the anti-reflection layer 2 is completed, the by-products attached to the sidewall surface of the patterned photoresist layer 3 can be effectively reduced, facilitating the subsequent removal of by-products and the patterned photoresist layer 3.

[0054] Specifically, the upper electrode power is 200W to 2000W; understandably, the upper electrode power can be any value from 200W to 2000W; for example, the upper electrode power can be 200W, 500W, 1000W, 1200W, 1500W, 1750W, 2000W, etc.

[0055] Specifically, the lower electrode power is 100W to 2500W; understandably, the lower electrode power can be any value from 100W to 2500W; for example, the lower electrode power can be 100W, 200W, 500W, 1000W, 1200W, 1500W, 2000W, 2250W, 2500W, etc.

[0056] Thus, the dry etching process uses low-frequency power, which can reduce the etching rate of the hard mask layer 1 material, thereby reducing the generation rate of polymer by-products. The by-products attached to the surface of the patterned photoresist layer 3 are fewer and easier to remove. In addition, in the dry etching process, the structure to be etched is mostly placed in a closed cavity bombarded by plasma to maintain the stability of various process conditions. The bombardment process under low-frequency power can reduce the polymer by-products inside the closed cavity, which facilitates subsequent cleaning and maintenance of the closed cavity, reduces maintenance costs, and also reduces the wear of components in the closed cavity, including the focusing ring that confines the plasma, the gas distribution disk that achieves uniform distribution of etching gas, and the electron adsorption disk that fixes the structure to be etched, thus extending the life of the components inside the closed cavity.

[0057] Specifically, the ambient air pressure during the etching process of the anti-reflection layer 2 is 50mT to 400mT. Understandably, this ambient air pressure is the air pressure in a sealed cavity, and the ambient air pressure can be any value from 50mT to 400mT. For example, the ambient air pressure can be 50mT, 60mT, 75mT, 80mT, 100mT, 150mT, 200mT, 300mT, 400mT, etc., which is beneficial for the gas circulation in the sealed cavity to remove the generated polymer byproducts, further reducing the amount of polymer byproducts adhering to the sidewall surface of the patterned photoresist layer 3, and reducing the difficulty of removing the polymer byproduct hard shell in the future.

[0058] Thus, the generation of polymer byproducts is significantly reduced during the etching process of the anti-reflection layer 2, and the generated polymer byproducts are made easier to remove. It also reduces polymer byproducts in the sealed cavity, making it easier to clean and maintain the sealed cavity and reducing maintenance costs. At the same time, it reduces the wear and tear of various equipment components in the sealed cavity and extends the life of the components in the sealed cavity to a certain extent.

[0059] Next, as 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 to produce fluoride ions, which react with hydrogen ions in the patterned photoresist layer 3 to generate hydrofluoric acid. Hydrofluoric acid can react with polymer byproducts to effectively destroy the hard shell of polymer byproducts attached to the sidewalls of the patterned photoresist layer 3, thus 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 40 sccm to 500 sccm. Understandably, the flow rate of carbon tetrafluoride can be any value within the range of 40 sccm to 500 sccm. For example, the flow rate of carbon tetrafluoride can be 40 sccm, 50 sccm, 100 sccm, 200 sccm, 300 sccm, 400 sccm, 500 sccm, etc. At this flow rate of carbon tetrafluoride, the polymer by-product hard shell attached to the sidewall 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 stability of the patterned photoresist layer 3.

[0064] Specifically, the cleaning agent also includes oxygen, which can react with the patterned photoresist layer 3 to remove the patterned photoresist layer 3, accelerating the reaction rate with the patterned photoresist layer 3. The oxygen flow rate in the cleaning agent is 16ccm to 500sccm. Understandably, the oxygen flow rate in the cleaning agent can be any value within the range of 16ccm to 500sccm. For example, the oxygen flow rate in the cleaning agent can be 16ccm, 20ccm, 50ccm, 100ccm, 200ccm, 300ccm, 400ccm, 500sccm, etc. Within this oxygen flow rate range, in combination with carbon tetrafluoride, the patterned photoresist layer 3 can be removed in the same process step that destroys the hard shell of surface polymer byproducts, 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 the semiconductor devices formed in subsequent semiconductor processes.

[0065] Furthermore, this etching method is applicable to various photoresist layer materials, various anti-reflection layer 2 materials, and various hard mask layer 1 materials; this application does not specifically limit these. For example, in conventional etching processes, 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 prone to etching up to the titanium nitride, leading to the loss of the hard mask layer 1. The bombarded Ti adheres to the sidewalls of the photoresist layer, forming a polymer hard shell. This polymer hard shell is difficult to remove, making the photoresist layer difficult to remove and affecting the yield and fabrication accuracy of subsequent semiconductor processes.

[0066] And such Figure 2As shown, compared with the surface morphology a) formed by etching in traditional processes, the etching method provided in this application increases the proportion of fluorine-containing gas in the etching gas used in the etching process of silicon oxynitride, reduces the etching power, and removes the material using a cleaning agent containing carbon tetrafluoride under gradually changing ESC temperature conditions. The steps work together to effectively reduce the generation rate of polymer by-products, reduce the loss of titanium nitride to reduce the amount of polymer by-products generated, and increase the activity of the generated polymer by-products to facilitate their removal during the cleaning process. Furthermore, the polymer by-products are easily destroyed by carbon tetrafluoride during the removal process to accelerate the removal of polymer by-products and photoresist layers. In this way, the difficulty of removing polymer by-products and photoresist layers is significantly reduced, enabling subsequent semiconductor processes to be carried out accurately and stably, and improving the morphological accuracy and performance stability of the final semiconductor device.

[0067] This application also provides a semiconductor device in which a patterned anti-reflection layer is formed based on the etching method described above, which is beneficial to improving the fabrication yield of the semiconductor device and improving the structural accuracy and performance of the semiconductor device.

[0068] This application also provides an electronic device, which includes any one of the semiconductor devices described in this application. The electronic device can be any electronic product or device such as a mobile phone, tablet computer, laptop computer, netbook, game console, television, VCD, DVD, navigator, camera, camcorder, voice recorder, MP3, MP4, PSP, etc., or it can be an intermediate product with the semiconductor device, such as a device motherboard with the semiconductor device. The use of the semiconductor device in this electronic device improves its working performance accordingly.

[0069] While this application discloses the above information, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of this application; therefore, the scope of protection of this application shall be determined by the scope defined in the claims.

Claims

1. An etching method, characterized in that, include: A structure to be etched is provided; the structure to be etched includes a semiconductor structure, a hard mask layer on the surface of the semiconductor structure, an anti-reflection layer on the hard mask layer, and a patterned photoresist layer on the anti-reflection layer, wherein the patterned photoresist layer has a first window; The anti-reflective layer is etched in the area corresponding to the first window to form a second window, resulting in a patterned anti-reflective layer. The etching gas used in the etching process of the anti-reflective 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 temperature conditions used in the etching process are gradually changing electrostatic adsorption temperatures, which can increase the activity of polymer by-products generated during the etching process. The temperature is raised to the target electrostatic adsorption temperature within a preset time, or the temperature is raised to the target electrostatic adsorption temperature in a single preset time and then kept stable, or there are multiple preset time periods, and the target electrostatic adsorption temperature is the same or different in each preset time period. The patterned photoresist layer is removed by a cleaning agent containing carbon tetrafluoride; Carbon tetrafluoride can ionize to produce fluoride ions, which react with hydrogen ions in the patterned photoresist layer to generate hydrofluoric acid. Hydrofluoric acid can react with polymer byproducts, destroying the hard shell of polymer byproducts attached to the sidewalls of the patterned photoresist layer.

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 also includes 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 electrostatic adsorption temperature is less than or equal to a preset temperature, which is 45℃~55℃.

4. The etching method according to claim 1, characterized in that, During the removal of the patterned photoresist layer, the flow rate of carbon tetrafluoride is 40 sccm to 500 sccm.

5. According to claim 1 4. The etching method according to any one of the claims, characterized in that, The etching process used in the anti-reflection layer is dry etching, and the power conditions for dry etching include the power of the upper electrode and the power of the lower electrode. The power of the upper electrode is 200W to 2000W; The power of the lower electrode is 100W to 2500W.

6. According to claim 1 4. The etching method according to any one of the claims, characterized in that, The ambient air pressure during the etching process of the anti-reflective layer is 50mT to 400mT.

7. According to claim 1 4. The etching method according to any one of the claims, characterized in that, The etching groove ratio of the structure to be etched is greater than the preset groove ratio, which is 70% to 95%.

8. A semiconductor device, characterized in that, Based on claim 1 7. A patterned antireflective layer is formed by the etching method described in any one of the claims.

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