Semiconductor devices and their manufacturing methods

Abstract

This invention provides a semiconductor device and a method for manufacturing the same. The method includes providing a semiconductor structure to be processed, the semiconductor structure including a stop layer, an etched layer covering the stop layer, and a photoresist layer on the etched layer, wherein the etched layer exposes a portion of the stop layer surface; and removing at least a portion of the photoresist layer using a dry photoresist stripping process, wherein the photoresist stripping gas used in the dry photoresist stripping process includes oxygen and a stop layer protective film forming gas. The semiconductor device manufacturing method provided by this invention can reduce the damage to the stop layer located below the etched layer caused by the photoresist stripping process, improving the quality of the obtained semiconductor device. The semiconductor device provided by this invention has high quality.

Description

Technical Field

[0001] This invention relates to the field of semiconductors, and more particularly to a semiconductor device and a method for manufacturing the same. Background Technology

[0002] With the development of semiconductor-related technologies, people have increasingly higher requirements for the quality of semiconductor structures, which in turn leads to continuous improvement in the requirements for processing technology.

[0003] Photolithography is a commonly used process in the fabrication of semiconductor structures. In order to ensure the etching of the etched layer, a photoresist layer needs to be formed on the surface of the etched layer. After the etching of the etched layer is completed, the photoresist layer is removed using a photoresist removal process.

[0004] However, current resist stripping processes can damage the stop layer located beneath the etched layer, affecting the quality of the semiconductor structure. Summary of the Invention

[0005] The technical problem solved by the present invention is to provide a semiconductor device and a method for manufacturing the same, so as to reduce the damage to the stop layer located below the etched layer caused by the resist stripping process and improve the quality of the obtained semiconductor device.

[0006] To address the above problems, the present invention provides a method for manufacturing a semiconductor device, comprising:

[0007] A semiconductor structure to be processed is provided, the semiconductor structure to be processed includes a stop layer, an etched layer covering the stop layer and a photoresist layer located on the etched layer, wherein the etched layer exposes a portion of the surface of the stop layer;

[0008] The photoresist layer, at least a portion of its thickness, is removed using a dry stripping process, wherein the stripping gas used in the dry stripping process includes oxygen and a stop layer protective film forming gas.

[0009] Optionally, the stop layer protective film forming gas includes a hydrogen-nitrogen mixture.

[0010] Optionally, the ratio of hydrogen to nitrogen in the hydrogen-nitrogen mixture is in the range of 1:23 to 1:25.

[0011] Optionally, the stop layer protective film forming gas includes water vapor.

[0012] Optionally, the ratio of the oxygen content to the water vapor content is in the range of 9:1 to 11:1.

[0013] Optionally, the degumming gas may also include nitrogen.

[0014] Optionally, the dry degumming equipment of the dry degumming process includes a degumming chamber, and an oxygen pipeline and a stop layer protective film forming gas pipeline connected to the degumming chamber.

[0015] Optionally, the temperature range of the degumming gas is 200℃-250℃.

[0016] Optionally, the desizing time range of the dry desizing process is 9-11 minutes.

[0017] Optionally, the material of the stop layer is aluminum nitride.

[0018] Optionally, the step of removing at least a portion of the photoresist layer using a dry stripping process further includes:

[0019] The stop layer of the semiconductor structure to be processed is subjected to surface smoothing treatment.

[0020] Optionally, the step of smoothing the surface of the stop layer of the semiconductor structure to be processed includes:

[0021] Argon gas is used to smooth the surface of the stop layer of the semiconductor structure to be processed.

[0022] Optionally, it also includes:

[0023] The remaining photoresist layer or photoresist residue is removed using a wet photoresist removal process.

[0024] Optionally, the wet stripper used in the wet etching process includes one or more of the following: N-methyl-2-pyrrolidone, dimethyl sulfoxide, 2-aminoethanol, tetramethylammonium hydroxide, ethanolamine, ethanolamine salts, tertiary amines, hydrogen fluoride, and ammonium hydroxide.

[0025] To address the aforementioned problems, embodiments of the present invention provide a semiconductor device, which is obtained by processing using the semiconductor device manufacturing method described in any of the preceding claims.

[0026] Compared with the prior art, the technical solution of the embodiments of the present invention has the following advantages:

[0027] The semiconductor device and its manufacturing method provided in this invention include the following steps: First, a semiconductor structure to be processed is provided, the semiconductor structure including a stop layer, an etched layer covering the stop layer, and a photoresist layer covering the etched layer; then, a dry resist stripping process is used to remove at least a portion of the photoresist layer, exposing a portion of the stop layer surface, and the resist stripping gas used in the dry resist stripping process includes oxygen and a stop layer protective film forming gas. In the semiconductor device manufacturing method provided in this invention, when removing the photoresist layer of the semiconductor structure, the presence of the stop layer protective film forming gas, due to the presence of oxygen and the stop layer protective film forming gas, allows a protective film to form on the surface of the stop layer, thereby preventing the wet resist stripping solution from corroding the stop layer in the subsequent wet resist stripping process. Simultaneously, in the dry resist stripping process, oxygen reacts with the photoresist layer to remove at least a portion of the photoresist layer, thus realizing the processing of the semiconductor structure and preparing for the subsequent wet resist stripping process. As can be seen, the semiconductor device manufacturing method provided in this embodiment of the invention includes a stop layer protective film forming gas in the gas used to remove the photoresist layer, thereby forming a protective film on the surface of the stop layer, preventing the stop layer from being corroded in the subsequent wet photoresist removal process, avoiding damage to the stop layer, and improving the quality of the semiconductor device. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0029] Figure 1 A schematic diagram of the structure of a semiconductor device obtained by a manufacturing method of a semiconductor device in the prior art;

[0030] Figures 2-4 This is a schematic diagram of the structure corresponding to each step of the semiconductor device manufacturing method provided in the embodiments of the present invention. Detailed Implementation

[0031] As is known from the background technology, the current resist stripping process can damage the stop layer located below the etched layer, affecting the quality of the semiconductor structure.

[0032] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a semiconductor device obtained by a manufacturing method of a semiconductor device in the prior art.

[0033] When removing the photoresist layer, a dry stripping process removes at least a portion of the photoresist. However, in the subsequent wet stripping process, the stop layer is etched by the wet stripping solution, such as... Figure 1 As shown, the stop layer 10 of the obtained semiconductor structure, which is not covered by the etched layer 11, is etched, thereby affecting the quality of the obtained semiconductor structure.

[0034] For example, when the semiconductor structure is a resonator structure, the material of the stop layer 10 is ALN and it serves as a piezoelectric layer, while the material of the etched layer 11 is the electrode material. The electrode material is etched by using photoresist patterning. However, during the removal of the photoresist after patterning, the surface of the ALN will be damaged, which will affect the performance of the formed resonator structure.

[0035] Therefore, improvements have been made to semiconductor device manufacturing methods, such as:

[0036] 1. Wet resist stripping solution was adjusted, but no wet resist stripping solution was found that could both remove photoresist and improve the corrosion of the stop layer.

[0037] 2. An additional protective layer is deposited on the surface of the stop layer in advance. When etching the layer to be etched, this protective layer is used as the stop layer. The etching can be stopped on this protective layer. After removing the photoresist layer, the protective layer is chemically etched. This not only increases the number of steps in the semiconductor processing, resulting in increased manufacturing costs, but also affects the performance of the device due to the setting of the protective layer.

[0038] It is evident that the semiconductor structure obtained by the semiconductor manufacturing method described above still cannot meet the performance requirements.

[0039] To reduce damage to the stop layer located beneath the etched layer caused by the resist stripping process and improve the quality of the resulting semiconductor device, embodiments of the present invention provide a method for manufacturing a semiconductor device, comprising:

[0040] A semiconductor structure to be processed is provided, the semiconductor structure to be processed includes a stop layer, an etched layer covering the stop layer and a photoresist layer located on the etched layer, wherein the etched layer exposes a portion of the surface of the stop layer;

[0041] The photoresist layer, at least a portion of its thickness, is removed using a dry stripping process, wherein the stripping gas used in the dry stripping process includes oxygen and a stop layer protective film forming gas.

[0042] The semiconductor device manufacturing method provided in this embodiment of the invention, when removing the photoresist layer of the semiconductor structure, uses a stripping gas that includes oxygen and a stop layer protective film forming gas. The presence of the stop layer protective film forming gas can form a protective film on the surface of the stop layer, thereby preventing the wet stripping solution from corroding the stop layer in the subsequent wet stripping process. At the same time, in the dry stripping process, oxygen reacts with the photoresist layer to remove at least a portion of the photoresist layer thickness, thus enabling the processing of the semiconductor structure and preparing for the subsequent wet stripping process.

[0043] As can be seen, the semiconductor device manufacturing method provided in this embodiment of the invention includes a stop layer protective film forming gas in the gas used to remove the photoresist layer, thereby forming a protective film on the surface of the stop layer, preventing the stop layer from being corroded in the subsequent wet photoresist removal process, avoiding damage to the stop layer, and improving the quality of the semiconductor device.

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] It should be noted that the orientation or positional relationship indicated in the embodiments of the present invention is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the purpose of facilitating and simplifying the description, and is not intended to indicate or imply that the device referred to must have a specific orientation or be constructed in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0046] Figures 2-4 This is a schematic diagram of the structure corresponding to each step of the semiconductor device manufacturing method provided in the embodiments of the present invention.

[0047] Please refer to Figure 2 A semiconductor structure to be processed is provided, the semiconductor structure to be processed includes a stop layer 100, an etched layer 110 covering the stop layer 100 and a photoresist layer 120 located on the etched layer 110, the etched layer 110 exposing a portion of the surface of the stop layer 100.

[0048] The semiconductor structure to be processed can provide a basis for the subsequent processing of semiconductor devices.

[0049] The semiconductor structure to be processed can be obtained after photolithography of the layer to be etched. In one specific embodiment, the semiconductor structure to be processed can be obtained through the following steps:

[0050] Forming a stop layer 100;

[0051] An etchable layer (i.e., the structure before the etched layer 110 in the figure is etched) is formed on the stop layer 100, and the etchable layer covers the stop layer 100.

[0052] A photoresist layer 120 is formed on the layer to be etched, and the photoresist layer 120 has the etching pattern of the layer to be etched.

[0053] According to the pattern of the photoresist layer 120, the layer to be etched is etched to obtain the etched layer 110, which exposes part of the surface of the stop layer 100.

[0054] In the process of semiconductor device manufacturing, multiple photolithography steps may be required. The materials of the stop layer 100 and the layer to be etched are not exactly the same in each photolithography step. As long as the etching rate of the material of the layer to be etched is much greater than the etching rate of the material of the layer below the layer to be etched in a single photolithography step, then the layer below the layer to be etched is the stop layer.

[0055] Of course, there can be other structures below the stop layer, such as the substrate 130 or a semiconductor structure that has already undergone other processing. In this embodiment, as shown in the figure, the stop layer includes a piezoelectric layer, and the etched layer includes a first electrode layer; the semiconductor structure to be processed also includes the substrate 130, a second electrode layer 150 located on the substrate 130, and the piezoelectric layer located above the second electrode layer 150 to meet the performance requirements of the resonant structure device.

[0056] In this embodiment, the stop layer 100 (piezoelectric layer) is made of aluminum nitride (ALN), and the etched layer (i.e., the layer to be etched, the first electrode layer) is made of a metal, such as tungsten or aluminum, to form a metal electrode to achieve the functional requirements of the device (e.g., an RF low-pass filter, a resonator). In other embodiments, the stop layer 100 can also be made of silicon, silicon dioxide, etc., and the etched layer can be made of other materials, as long as the etch can stop the process. Please refer to [reference needed]. Figure 3 The photoresist layer 120, at least a portion of its thickness, is removed using a dry stripping process, wherein the stripping gas used in the dry stripping process includes oxygen and a stop layer protective film forming gas.

[0057] The photoresist stripping process uses a gas containing oxygen and a stop layer protective film forming gas. The oxygen can react with the photoresist to remove at least a portion of the photoresist layer thickness. At the same time, the presence of the stop layer protective film forming gas can form a protective film 140 on the surface of the stop layer 100, thereby protecting the stop layer 100 in subsequent processes and reducing the probability of corrosion.

[0058] In this embodiment, the material of the stop layer 100 is aluminum nitride, and the gas forming the stop layer protective film includes a hydrogen-nitrogen mixture. The presence of the hydrogen-nitrogen mixture causes the protective film 140 to form on the surface of the stop layer 100. This may be because the presence of the hydrogen-nitrogen mixture accelerates the reaction between oxygen and aluminum nitride to form a layer of aluminum oxide, thereby blocking the direct contact between the wet adhesive remover and the aluminum nitride in the subsequent wet adhesive removal process. Alternatively, it may be that the aluminum nitride reacts with oxygen and the hydrogen-nitrogen mixture to form a layer of aluminum hydroxide, which also blocks the direct contact between the wet adhesive remover and the aluminum nitride in the subsequent wet adhesive removal process.

[0059] To ensure the formation of the stop layer protective film, the ratio of hydrogen to nitrogen in the hydrogen-nitrogen mixture can be in the range of 1:23-1:25, for example, 1:24.

[0060] In another embodiment, the stop layer 100 is made of aluminum nitride, and the gas forming the stop layer protective film includes water vapor. The presence of water vapor causes the protective film 140 to form on the surface of the stop layer 100. This may be because the presence of water vapor accelerates the reaction between oxygen and aluminum nitride to form a layer of aluminum oxide, thereby preventing direct contact between the subsequent wet desizing solution and the aluminum nitride. Alternatively, it may be that aluminum nitride reacts with water to form a layer of aluminum hydroxide, also preventing direct contact between the subsequent wet desizing solution and the aluminum nitride. In other embodiments, the presence of water vapor may promote or directly react with the stop layer 100 and other materials, forming a protective film of other materials.

[0061] Using a dry stripping process to remove at least a portion of the photoresist layer 120 means that, in this embodiment, only the portion of the photoresist layer 120 with higher hardness can be removed, and the remaining photoresist layer 120 with lower hardness can be removed by a subsequent wet stripping process. In other embodiments, all of the photoresist layer 120 can be removed, but some residue will still remain at the contact surface between the photoresist layer 120 and the etched layer 110, which can be further removed by a subsequent wet stripping process to improve the thoroughness of the removal of the photoresist layer 120, thereby improving the quality of the semiconductor structure.

[0062] Specifically, the equipment used in the dry resist stripping process is a dry resist stripping device, including a stripping chamber and an oxygen pipeline and a stop layer protective film forming gas pipeline connected to the stripping chamber. When performing dry resist stripping on a semiconductor structure, the semiconductor structure is placed in the stripping chamber, and then oxygen and stop layer protective film forming gas are introduced into the stripping chamber through the oxygen pipeline and the stop layer protective film forming gas pipeline to achieve dry resist stripping of the semiconductor structure. The setting of the stop layer protective film forming gas pipeline in the dry resist stripping device ensures the realization of the semiconductor device manufacturing method provided in this embodiment of the invention, while requiring minimal changes to the equipment, thus reducing the manufacturing cost of the semiconductor device provided in this embodiment of the invention.

[0063] Of course, it is easy to understand that the other end of the oxygen pipeline is connected to the oxygen source, and the other end of the stop layer protective membrane forms the gas source.

[0064] Of course, in order to ensure the effectiveness of dry resist removal, the temperature during the dry resist removal process also needs to be controlled. If the temperature is too high, it will affect the performance of the semiconductor structure, and if the temperature is too low, it will affect the removal efficiency of the photoresist layer 120. Therefore, in this embodiment, the temperature range of the resist removal gas is 200℃-250℃, such as 210℃, 220℃, 225℃, and 234℃, so as to ensure the removal efficiency of the photoresist layer 120 without affecting the performance of the semiconductor structure, and thus ensure the processing efficiency of the semiconductor structure.

[0065] In addition, the removal time of the dry resist stripping process also affects the removal effect of the photoresist layer 120. If the time is too long, the amount of photoresist removed can be increased, but it will reduce the processing efficiency of the semiconductor structure. If the time is too short, the amount of photoresist layer 120 removed will not meet the requirements. For example, the harder parts of the surface of the photoresist layer 120 will not be completely removed, which will affect subsequent processing. Therefore, in this embodiment, the removal time of the dry resist stripping process is in the range of 9 minutes to 11 minutes, such as 10 minutes, so as to meet the removal requirements of the photoresist layer 120 while shortening the removal time, improving processing efficiency, and reducing processing costs.

[0066] Furthermore, the ratio of oxygen content in the stripping gas to the gas content of the stop layer protective film forming gas also affects the removal speed of the photoresist layer 120. Excessive oxygen content will affect the formation of the protective film 140 on the surface of the stop layer 100, while insufficient oxygen content will affect the removal efficiency of the photoresist layer 120. In this embodiment, when the stop layer protective film forming gas is water vapor, the ratio of oxygen to water vapor content in the stripping gas is in the range of 9:1 to 11:1, for example, 10:1. This ensures that, on the one hand, the protective film 140 can be formed on the surface of the stop layer 100, and on the other hand, the removal efficiency of the photoresist layer 120 can be guaranteed.

[0067] In another specific embodiment, when the stop layer protective film forming gas is water vapor, the photoresist stripping gas may also include nitrogen gas to adjust the oxygen and water vapor content in the photoresist stripping gas, ensuring that the removal rate of the photoresist layer 120 matches the formation rate of the protective film 140. It can be seen that the semiconductor device manufacturing method provided by this embodiment adds water vapor to the gas used to remove the photoresist layer, thereby enabling the formation of a protective film 140 on the surface of the stop layer, preventing corrosion of the stop layer during subsequent wet photoresist stripping, avoiding damage to the stop layer, and improving the quality of the semiconductor device.

[0068] like Figure 1 As shown, due to the lattice structure of the stop layer 100, its surface is uneven and has sharp corners. Therefore, during the subsequent wet stripping process, the wet stripping solution will corrode the stop layer 100 along these sharp corners, exacerbating the corrosion and further unevenness of the stop layer surface, resulting in increased surface roughness. To reduce damage to the stop layer 100 from the wet stripping solution during the subsequent wet stripping process, the step of removing at least a portion of the photoresist layer 120 using a dry stripping process may further include:

[0069] The stop layer 100 of the semiconductor structure to be processed is subjected to surface smoothing treatment.

[0070] In this embodiment, before the dry resist stripping process removes at least a portion of the photoresist layer 120, the stop layer 100 of the semiconductor structure to be processed undergoes surface smoothing treatment. Smoothing the surface of the stop layer 100 reduces sharp corners, thereby reducing corrosion. Simultaneously, it allows for the formation of a smoother protective film during the dry resist stripping process, ensuring the effectiveness of the protective film formation and thus guaranteeing protection of the stop layer 100 during subsequent wet resist stripping.

[0071] In this embodiment, argon gas can be used to smooth the surface of the stop layer 100 of the semiconductor structure to be processed. Argon gas has strong bombardment power, which can ensure the effectiveness of the surface smoothing treatment. In other embodiments, other gases can also be used to achieve the surface smoothing treatment of the stop layer.

[0072] When using argon gas to smooth the surface of the stop layer 100 of the semiconductor structure to be processed, the temperature of the argon gas can be room temperature, the duration can be 50s-70s, such as 60s, and the flow rate of the argon gas can be 90sccm-110sccm.

[0073] In another specific implementation, please refer to Figure 4The remaining photoresist layer or photoresist residue is removed using a wet photoresist removal process.

[0074] After dry photoresist removal, a wet photoresist removal process is used to remove the remaining photoresist layer or photoresist residue.

[0075] The semiconductor structure after dry resist removal is placed in a wet resist remover solution to remove the remaining photoresist layer 120 or photoresist residue.

[0076] Of course, other unwanted structures can also be removed, such as polymers formed on the sidewalls of the etching grooves during the etching process, to improve the performance of the semiconductor structure.

[0077] Specifically, the wet stripper used in the wet etching process includes one or more of the following: N-methyl-2-pyrrolidone, dimethyl sulfoxide, 2-aminoethanol, tetramethylammonium hydroxide, ethanolamine, ethanolamine salts, tertiary amines, hydrogen fluoride, and ammonium hydroxide.

[0078] Thus, in the semiconductor device manufacturing method provided by the present invention, when removing the photoresist layer using a dry photoresist stripping process, a stop layer protective film forming gas is added to the gas used, which can form a protective film 140 on the surface of the stop layer. When further removing the remaining photoresist layer or photoresist residue using a wet photoresist stripping process, the protective film 140 can prevent the stop layer from being corroded, avoid damage to the stop layer, and improve the quality of the semiconductor device.

[0079] To address the aforementioned problems, this invention also provides a semiconductor device, which is manufactured using the semiconductor device manufacturing method described above, and has high quality, meeting quality requirements.

[0080] While the embodiments of the present invention have been disclosed above, the present invention is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for manufacturing a semiconductor device, characterized in that, include: A semiconductor structure to be processed is provided, the semiconductor structure to be processed includes a stop layer, the material of the stop layer is aluminum nitride, an etched layer covering the stop layer and a photoresist layer located on the etched layer, the etched layer exposing a portion of the surface of the stop layer; The photoresist layer, at least a portion of its thickness, is removed using a dry photoresist stripping process. The stripping gas used in the dry photoresist stripping process includes both oxygen and a stop layer protective film forming gas. The oxygen reacts with the photoresist layer to remove at least a portion of its thickness. The presence of the stop layer protective film forming gas causes a protective film to form on the surface of the stop layer. The material of the protective film includes aluminum hydroxide. Before or after the step of removing the photoresist layer, at least a portion of its thickness, the process further includes: performing a surface smoothing treatment on the stop layer of the semiconductor structure to be processed.

2. The method for manufacturing a semiconductor device as described in claim 1, characterized in that, The gas forming the stop layer protective film includes a mixture of hydrogen and nitrogen.

3. The method for manufacturing a semiconductor device as described in claim 2, characterized in that, The ratio of hydrogen to nitrogen in the hydrogen-nitrogen mixture is in the range of 1:23 to 1:

25.

4. The method for manufacturing a semiconductor device as described in claim 1, characterized in that, The stop layer protective film forms a gas including water vapor.

5. The method for manufacturing a semiconductor device as described in claim 4, characterized in that, The ratio of oxygen to water vapor is in the range of 9:1 to 11:

1.

6. The method for manufacturing a semiconductor device as described in claim 4, characterized in that, The degumming gas also includes nitrogen.

7. The method for manufacturing a semiconductor device as described in claim 1, characterized in that, The temperature range of the degumming gas is 200℃-250℃.

8. The method for manufacturing a semiconductor device as described in claim 1, characterized in that, The descaling time range for the dry descaling process is 9-11 minutes.

9. The method for manufacturing a semiconductor device as described in claim 1, characterized in that, The stop layer includes a piezoelectric layer, and the etched layer includes a first electrode layer; The semiconductor structure to be processed also includes a substrate, a second electrode layer on the substrate, and a piezoelectric layer located above the second electrode layer.

10. The method for manufacturing a semiconductor device as claimed in claim 1, characterized in that, The step of performing surface smoothing treatment on the stop layer of the semiconductor structure to be processed includes: Argon gas is used to smooth the surface of the stop layer of the semiconductor structure to be processed.

11. A method for manufacturing a semiconductor device according to any one of claims 1-10, characterized in that, Also includes: The remaining photoresist layer or photoresist residue is removed using a wet photoresist removal process.

12. The method for manufacturing a semiconductor device as described in claim 11, characterized in that, The materials used in wet etching processes include one or more of the following: N-methyl-2-pyrrolidone, dimethyl sulfoxide, 2-aminoethanol, tetramethylammonium hydroxide, ethanolamine, ethanolamine salts, tertiary amines, hydrogen fluoride, and ammonium hydroxide.

13. A semiconductor device, characterized in that, Obtained by processing using the manufacturing method of a semiconductor device as described in any one of claims 1-12.

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