A method of manufacturing dual shallow trench isolation and a semiconductor structure

Abstract

The application belongs to the technical field of semiconductor manufacturing, and discloses a method for manufacturing double shallow trench isolation and a semiconductor structure; wherein the method comprises the following steps: on a selected semiconductor substrate, a substrate oxide layer, a substrate silicon nitride layer, a sacrifice layer, a bottom anti-reflective coating and a photoresist are sequentially deposited, and a patterned sacrifice layer is formed through a photolithography process; a pre-set thickness of a grinding barrier layer and a first dielectric layer are sequentially deposited on the patterned sacrifice layer, the first dielectric layer is processed through a chemical mechanical grinding process, and the grinding barrier layer is removed through an etching process, so as to form a channel of a logic region and a channel of a pixel region in sequence; a second dielectric layer is deposited and chemically mechanically ground, and finally a double shallow trench isolation structure is obtained. The technical scheme disclosed by the application solves the technical problems of silicon nitride residue and different silicon oxide heights of the logic region and the pixel region existing in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor manufacturing technology, and specifically relates to a method for manufacturing dual shallow trench isolation and a semiconductor structure. Background Technology

[0002] Complementary metal-oxide-semiconductor (CMOS) image sensors have logic regions and pixel regions. As the pixel size of CMOS image sensors (CIS) becomes smaller, in order to increase the photosensitive area of ​​the pixel region and improve dark current, the shallow trench isolation depth used in the pixel region needs to be made shallower, resulting in a discrepancy between the shallow trench isolation depth of the pixel region and the logic region.

[0003] In view of the above actual situation, the current technical solution uses two photolithography and two etching methods to solve the problem. The specific steps include: first, etching the first channel and the second channel to the same depth; then, covering the second channel with photoresist, and then etching the first channel separately to the final specified depth to form the final channel. In the process of the above-mentioned existing technical solution, a portion of the silicon nitride (SiN) around the first channel is consumed as an etching hard mask layer, while the SiN around the second channel is protected by the photoresist as a barrier layer, thus forming a SiN height difference. Specific examples illustrate the steps included in the prior art solution as follows: Step S1: Initial structure and channel etching, including: the initial structure consists of a silicon substrate, a substrate oxide layer, a silicon nitride layer, an AC layer (anti-reflective coating or hard mask), and a silicon insulating layer (SiON), the silicon insulating layer serving as a top protective layer or anti-reflective layer; etching a first channel and a second channel in the logic region and pixel region respectively, each channel serving to isolate different device regions and prevent electrical crosstalk. Step S2: Depositing a polishing barrier layer and a first dielectric layer, including: depositing a polishing barrier layer, which can be silicon nitride or silicon carbide, serving as a stop layer in the subsequent chemical mechanical polishing process to protect the underlying structure from over-polishing; depositing a first dielectric layer to fill the channels and provide preliminary electrical isolation, the first dielectric layer typically being silicon oxide. Step S3: Logic region photoresist coating and final channel etching, including: coating the pixel region with photoresist (PR) to protect the pixel region structure; further etching the final channel in the logic region based on the first channel to refine the isolation structure of the logic region. Step S4: Depositing a TEOS oxide layer and removing the photoresist, including: depositing a TEOS (tetraethoxysilane) oxide layer as an additional isolation or protective layer; removing the photoresist in the pixel region in preparation for subsequent pixel region-specific processes. Step S5: Step height formation and silicon nitride etching. Step S6: Substrate oxide etching and SiN residue treatment.

[0004] The SiN height difference formed by the above-mentioned existing technical solutions will further cause the SiN height of the logic region and the pixel region to be inconsistent after chemical mechanical polishing (CMP). At the same time, it will cause oxide residues at the junction of adjacent logic regions and pixel regions. After the subsequent SiN removal process, there are technical problems of SiN residues and different SiO2 heights in the logic region and pixel region, which will have a certain impact on the yield. Summary of the Invention

[0005] The purpose of this invention is to provide a method for manufacturing dual shallow trench isolation (DSTI) and a semiconductor structure to solve one or more of the aforementioned technical problems. Specifically, this invention provides a method for improving the step height in dual shallow trench isolation (DSTI), applicable to the manufacture of semiconductor devices such as CMOS image sensors. This method solves the technical problems in existing solutions, such as oxide residue at the junction of adjacent logic regions and pixel regions, SiN residue after SiN removal, and different SiO2 heights between logic and pixel regions.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a method for manufacturing a dual shallow trench barrier, comprising the following steps:

[0008] On the selected semiconductor substrate, a substrate oxide layer, a substrate silicon nitride layer, a sacrificial layer, a bottom anti-reflective coating, and a photoresist are deposited sequentially, and a patterned sacrificial layer is formed by photolithography to define the channels of the logic area and the pixel area.

[0009] A pre-defined abrasion barrier layer and a first dielectric layer are sequentially deposited on a patterned sacrificial layer, and the first dielectric layer is treated by a chemical mechanical polishing process, with the polishing stopping at the abrasion barrier layer.

[0010] The excess portion of the polishing barrier layer is removed by etching process, and only the polishing barrier layer portion below the first dielectric layer after chemical mechanical polishing is retained after the removal process.

[0011] The pixel area is covered with photoresist, and the channel of the logic area is formed by etching through an etching process; the photoresist covering the pixel area is removed, and the channel of the pixel area is formed by etching through an etching process.

[0012] A second dielectric layer is deposited in the channel of the logic region and the channel of the pixel region, and the second dielectric layer is treated by chemical mechanical polishing process to make the height of the topmost substrate silicon nitride layer of the logic region and the pixel region consistent, thus obtaining a dual shallow channel isolation structure.

[0013] A further improvement of the technical solution of the present invention is that the semiconductor substrate is specifically a silicon substrate.

[0014] A further improvement of the technical solution of the present invention is that, in the step of sequentially depositing the substrate oxide layer, the substrate silicon nitride layer, the sacrificial layer, the bottom anti-reflection coating and the photoresist, a chemical vapor deposition method is used to deposit a layer of silicon oxide on the surface of the semiconductor substrate as the substrate oxide layer.

[0015] A further improvement of the technical solution of the present invention is that, in the step of sequentially depositing the substrate oxide layer, the substrate silicon nitride layer, the sacrificial layer, the bottom anti-reflection coating and the photoresist, a chemical vapor deposition method is used to deposit a layer of silicon nitride on the substrate oxide layer as the substrate silicon nitride layer.

[0016] A further improvement of the technical solution of the present invention is that, in the step of sequentially depositing a substrate oxide layer, a substrate silicon nitride layer, a sacrificial layer, a bottom anti-reflective coating, and a photoresist, the sacrificial layer is deposited on the substrate silicon nitride layer by chemical vapor deposition or physical vapor deposition; wherein, the material of the sacrificial layer is polycrystalline silicon or silicon oxide.

[0017] A further improvement to the technical solution of the present invention lies in that, in the step of forming a patterned sacrificial layer through photolithography,

[0018] First, a lithography machine is used to expose the designed lithographic pattern onto the photoresist, and an opening or retention area corresponding to the lithographic pattern is formed on the photoresist to form a patterned photoresist. Then, using the patterned photoresist as a mask, the sacrificial layer is etched by dry etching or wet etching to remove the sacrificial layer material below the opening of the photoresist, thus forming a patterned sacrificial layer.

[0019] A further improvement of the technical solution of the present invention lies in the step of covering the pixel area with photoresist and etching to form the channel of the logic area through an etching process; removing the photoresist covering the pixel area and etching to form the channel of the pixel area through an etching process,

[0020] The pixel area is covered with photoresist, and the film structure of the logic area is etched by dry etching or wet etching. The substrate silicon nitride layer, substrate oxide layer and semiconductor substrate of the logic area are removed in sequence to form the channel of the logic area.

[0021] The photoresist covering the pixel area is removed to expose the film structure of the pixel area. The film structure of the pixel area is then etched using dry or wet etching methods. The substrate silicon nitride layer, substrate oxide layer, and semiconductor substrate of the pixel area are etched and removed in sequence to form the channel of the pixel area.

[0022] A further improvement of the technical solution of the present invention is that the materials of the first dielectric layer and the second dielectric layer are both silicon oxide or silicon oxynitride.

[0023] The present invention provides a semiconductor structure comprising dual shallow trench isolation, wherein the dual shallow trench isolation is manufactured using any of the methods described above in the present invention.

[0024] A further improvement of the technical solution of the present invention is that the semiconductor structure is specifically a CMOS image sensor.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] This invention specifically discloses a method for manufacturing dual shallow trench isolation. Without adding a photomask, it defines the trench positions of the pixel region and the logic region through a sacrificial layer. Furthermore, unlike existing technologies, this invention first forms the trench for the logic region and then the trench for the pixel region, ultimately satisfying the respective depth requirements of both the logic region and pixel region trenches. This results in shallow trench isolation of different depths, meeting the different isolation requirements of the logic region and pixel region in semiconductor structures such as CMOS image sensors. Moreover, the remaining polishing barrier layer and sacrificial layer after deposition and polishing serve as transition sacrificial layers. During the second chemical mechanical polishing, these layers prevent the underlying substrate silicon nitride layer from being polished, ensuring that the remaining substrate silicon nitride layers in the pixel region and the logic region are highly consistent. In other words, this invention achieves highly consistent substrate silicon nitride layers at the top of the logic region and the pixel region through chemical mechanical polishing, stopping at the polishing barrier layer. In summary, the technical solution of this invention, without adding a photomask, ensures that the substrate silicon nitride layer height is consistent in the logic area and pixel area after chemical mechanical polishing through the design of a sacrificial layer and a polishing barrier layer. This allows the subsequent SiN removal process to uniformly remove silicon nitride without producing SiN residue. In addition, the technical solution of this invention avoids silicon dioxide accumulation at the junction of regions, preventing silicon dioxide residue at the junction of adjacent logic areas and pixel areas, and also solves the technical problem of different SiO2 heights. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in this invention 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 some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a flowchart illustrating a method for manufacturing a dual shallow trench barrier, as described in an embodiment of the present invention.

[0029] Figure 2 This is a schematic diagram illustrating the principle of a method for manufacturing a dual shallow trench isolation system according to an embodiment of the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention; obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0031] Based on the technical solutions disclosed in the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. 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 device that includes 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 these processes, methods, products, or devices.

[0032] Please see Figure 1 This invention provides a method for manufacturing a dual shallow trench barrier, comprising the following steps:

[0033] Step 1: On the selected semiconductor substrate, a substrate oxide layer, a substrate silicon nitride layer, a sacrificial layer, a bottom anti-reflection coating (BARC), and photoresist are deposited sequentially, and a patterned sacrificial layer is formed by photolithography to define the channels for the subsequent logic area and pixel area.

[0034] Step 2: Sequentially deposit a polishing barrier layer and a first dielectric layer of a certain thickness on the patterned sacrificial layer, and process the first dielectric layer by chemical mechanical polishing (CMP) until polishing stops at the polishing barrier layer; exemplaryly, polishing stops at the upper surface of the polishing barrier layer; interpretably, the upper surface of the polishing barrier layer is the side of the polishing barrier layer away from the substrate; correspondingly, the lower surface of the polishing barrier layer is the side of the polishing barrier layer closer to the substrate.

[0035] Step 3: Remove the excess portion of the polishing barrier layer by etching process, and retain only the polishing barrier layer portion below the first dielectric layer after chemical mechanical polishing process.

[0036] Step 4: Cover the pixel area with photoresist using photolithography, and etch the channel of the logic area using etching; in other words, cover the pixel area and open the logic area; remove the photoresist covering the pixel area, and etch the channel of the pixel area using etching.

[0037] Step 5: Deposit a second dielectric layer in the channels of the logic region and the pixel region, and process the second dielectric layer by chemical mechanical polishing (CMP) to make the height of the topmost substrate silicon nitride layer in the logic region and the pixel region consistent, thus obtaining dual shallow channel isolation; wherein, the polishing stops at the lower surface of the polishing barrier layer below the first dielectric layer after CMP, or it can be the upper surface of the substrate silicon nitride layer.

[0038] The technical solution disclosed in this invention specifically provides a method for forming logic region and pixel region channels on a semiconductor substrate, aiming to solve the technical problems of complex channel formation process and difficulty in ensuring the height consistency of logic region and pixel region in the prior art. The method of this invention simplifies process steps, improves production efficiency, and ensures the height consistency of the silicon nitride layer on the substrate in the logic region and pixel region, thereby improving the performance of the semiconductor device. This invention, through reasonable process design, greatly simplifies the channel formation process steps compared to the prior art, improves production efficiency, and reduces production costs. By employing chemical mechanical polishing (CMP) technology and setting polishing barrier layers in key steps, the height of different film layers in the logic region and pixel region can be precisely controlled, effectively ensuring the height consistency of the topmost SiN film layer in the logic region and pixel region, thereby improving the performance and reliability of the semiconductor device. Furthermore, in the photolithography process, by optimizing the selection of photoresist and the setting of photolithography parameters, combined with the use of a bottom anti-reflective coating, light reflection and interference are reduced, improving the resolution and accuracy of the photolithography pattern, making the formed channel position and shape more accurate, which is beneficial to improving device performance.

[0039] Please see Figure 2 , Figure 2 The colors of each layer are explained as follows: the substrate is dark gray, the substrate oxide layer is green, the substrate silicon nitride layer is yellow, the sacrificial layer is light gray, the bottom anti-reflective coating is orange, the photoresist is bright yellow, the polishing barrier layer is blue, and the first dielectric layer is emerald green.

[0040] In a specific exemplary technical solution of the present invention, a method for manufacturing dual shallow trench isolation is provided, comprising the following steps:

[0041] Step S1, initial layer deposition and patterned sacrificial layer formation; wherein, the initial structure consists of multiple layers of materials, including a bottom substrate, a substrate oxide layer, a substrate silicon nitride layer, a sacrificial layer, a bottom anti-reflective coating, and photoresist; further, a patterned sacrificial layer is formed by photolithography to define the channels for subsequent logic regions and pixel regions; these layers provide the basis for subsequent channel etching and filling.

[0042] Step S2: Sequentially deposit a polishing barrier layer and a first dielectric layer of a certain thickness on the patterned sacrificial layer;

[0043] Step S3: The first dielectric layer is treated by chemical mechanical polishing process, and the polishing stops at the upper surface of the polishing barrier layer;

[0044] Step S4: Remove the polishing barrier layer by etching process, including the polishing barrier layer above and on both sides of the patterned sacrificial layer; only the polishing barrier layer below the first dielectric layer after chemical mechanical polishing is retained.

[0045] Step S5: Cover the pixel area with photoresist using a photolithography process;

[0046] Step S6: The channel 1 of the logic region is formed by etching through an etching process; in other words, the pixel area is covered and the logic region is opened.

[0047] Step S7: Remove the photoresist covering the pixel area and etch the trench 2 of the pixel area through an etching process;

[0048] Step S8: Fill trench 1 and trench 2 with dielectric material. The filling material needs to have good insulation properties and filling capacity to ensure effective isolation of the trenches. In the exemplary technical solution, silicon oxide can be selected as the dielectric material.

[0049] Step S9: The filled surface is smoothed by chemical mechanical polishing (CMP). The CMP process uses polishing fluid and polishing pads to remove excess material from the surface and achieve the required smoothness.

[0050] In this embodiment of the invention, after a series of process steps, the final STI structure is formed, the channels of the logic area and the pixel area are effectively isolated, and the surface is flat, providing a good foundation for subsequent device manufacturing and interconnection.

[0051] As a specific embodiment of the technical solution of the present invention, in the initial layer deposition step...

[0052] The selected semiconductor substrate is a silicon substrate or other suitable substrate material commonly used in semiconductor manufacturing, and then the following layers are deposited sequentially on the substrate.

[0053] Regarding the substrate oxide layer: A layer of silicon oxide (SiO2) can be deposited on the substrate surface as the substrate oxide layer using methods such as chemical vapor deposition. This oxide layer can isolate the substrate from other layers and prevent impurities in the substrate from diffusing into the subsequently deposited film layers, thus affecting device performance. The deposition thickness can be controlled according to specific process requirements, generally between tens of nanometers and hundreds of nanometers.

[0054] Regarding the silicon nitride substrate layer: A silicon nitride (SiN) layer is deposited on the substrate oxide layer using the same chemical vapor deposition technique. The silicon nitride layer exhibits high hardness and good chemical stability, making it suitable as a support and protective layer for subsequent processes; the deposition thickness is typically between tens of nanometers and over one hundred nanometers.

[0055] Regarding the sacrificial layer: suitable materials, such as polycrystalline silicon or silicon oxide, can be selected and a sacrificial layer is deposited on the silicon nitride substrate using methods such as chemical vapor deposition or physical vapor deposition (PVD). The role of the sacrificial layer is to form specific structures or spaces by removal in subsequent processes. Its thickness is determined according to design requirements, generally ranging from several hundred nanometers to several micrometers.

[0056] Regarding the bottom anti-reflective coating (BRAC): A bottom anti-reflective coating can be applied to the sacrificial layer using methods such as spin coating. BRAC can reduce light reflection and interference during photolithography, improving the resolution and accuracy of the photolithographic pattern. The coating thickness is generally between tens and hundreds of nanometers, depending on the requirements of the photolithography process.

[0057] Regarding photoresist (PR): A layer of photoresist is spin-coated onto the bottom anti-reflective coating. Photoresist is a key material in the photolithography process, used to transfer photolithographic patterns onto the substrate. The appropriate type of photoresist, such as positive or negative photoresist, is selected, and its coating thickness is controlled according to process requirements, typically ranging from several hundred nanometers to several micrometers.

[0058] As a specific embodiment of the technical solution of the present invention, in the step of forming a patterned sacrificial layer by photolithography...

[0059] First, the designed photolithography pattern is exposed onto the photoresist using a photolithography machine. Depending on the type of photoresist, such as positive or negative, after development and other steps, openings or retention areas corresponding to the desired pattern are formed on the photoresist.

[0060] Then, using patterned photoresist as a mask, the sacrificial layer is etched by dry etching or wet etching to remove the sacrificial layer material below the photoresist opening, forming a patterned sacrificial layer. This patterned sacrificial layer is used to define the channel position and shape of the subsequent logic area and pixel area.

[0061] As a specific embodiment of the technical solution of the present invention, in the step of depositing the grinding barrier layer and the first dielectric layer and performing chemical mechanical polishing...

[0062] During the deposition of the polishing barrier layer, methods such as chemical vapor deposition are used to deposit the polishing barrier layer on the patterned sacrificial layer and the remaining photoresist. The polishing barrier layer material can be selected from materials with high hardness and good chemical stability, such as silicon nitride and silicon carbide. Its thickness is controlled according to the requirements of subsequent chemical mechanical polishing, generally between tens of nanometers and hundreds of nanometers. The function of this layer is to act as a polishing stop layer during chemical mechanical polishing, protecting the underlying film layer from over-polishing.

[0063] When depositing the first dielectric layer, the first dielectric layer is deposited on the polishing barrier layer. The dielectric layer material can be silicon oxide, silicon oxynitride, etc. The deposition method can be chemical vapor deposition or physical vapor deposition, etc. The deposition thickness is determined according to the design requirements, generally between several hundred nanometers and several micrometers.

[0064] During chemical mechanical polishing (CMP), a CMP device is used to polish the first dielectric layer. During the polishing process, the chemical components in the polishing slurry react chemically with the dielectric layer material, while the polishing head mechanically polishes the surface of the dielectric layer. These two processes work together to planarize the dielectric layer. The polishing process continues until the polishing barrier layer is exposed, at which point the polishing stops. At this point, the first dielectric layer above the logic area and the pixel area reaches a substantially uniform height.

[0065] As a specific embodiment of the technical solution of the present invention, the step of removing part of the polishing barrier layer specifically includes:

[0066] By employing dry or wet etching methods and selecting appropriate etching gases or etchants, the polishing barrier layer can be selectively etched. By precisely controlling the etching conditions, the polishing barrier layer on the surface of the first dielectric layer and on both sides of the patterned sacrificial layer can be removed, while the polishing barrier layer below the first dielectric layer can be retained. This provides a suitable structural basis for subsequent processes.

[0067] As a specific embodiment of the technical solution of the present invention, during the process of forming the logic area channel and the pixel area channel...

[0068] After completing the above steps, a new layer of photoresist is spin-coated onto the substrate. Then, the designed photolithographic pattern is exposed onto the photoresist using a photolithography machine. After development and other steps, a pattern covering the pixel area is formed on the photoresist, meaning the pixel area is protected by the photoresist while the logic area is exposed. Using the patterned photoresist as a mask, the film layer of the logic area is etched using methods such as dry etching or wet etching. The substrate silicon nitride layer, substrate oxide layer, and substrate are etched away sequentially to form channel 1 of the logic area. The etching depth and shape are precisely controlled according to design requirements.

[0069] Then, a suitable solvent is used to remove the photoresist covering the pixel area, exposing the film layer of the pixel area. Based on the remaining film layer structure, the film layer of the pixel area is etched by dry etching or wet etching, sequentially removing the substrate silicon nitride layer, substrate oxide layer, and substrate of the pixel area to form the channel 2 of the pixel area. During the etching process, the etching conditions must be precisely controlled to ensure that the depth and shape of the channel 2 of the pixel area meet the design requirements.

[0070] As a specific embodiment of the technical solution of the present invention, in the steps of depositing the second dielectric layer and chemically mechanically polishing to obtain a highly uniform SiN film layer...

[0071] A second dielectric layer is deposited in channels 1 and 2 and on the entire substrate surface using methods such as chemical vapor deposition. The material of the second dielectric layer can be the same as or different from that of the first dielectric layer, such as silicon oxide or silicon oxynitride. The deposition thickness is controlled according to design requirements, generally between tens and hundreds of nanometers. This dielectric layer serves to fill the channels, isolate different areas, and protect the device. Then, the second dielectric layer is polished using chemical mechanical polishing (CMP). During the polishing process, the polishing parameters are precisely controlled, and polishing stops at the lower surface of the polishing barrier layer. Since the SiN film under the polishing barrier layer is continuous and of uniform thickness in both the logic and pixel regions, after this CMP polishing, the topmost SiN film in the logic and pixel regions achieves a high degree of uniformity, thereby improving the performance and reliability of the semiconductor device.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for manufacturing a double shallow trench barrier, characterized in that, Includes the following steps: On the selected semiconductor substrate, a substrate oxide layer, a substrate silicon nitride layer, a sacrificial layer, a bottom anti-reflective coating, and a photoresist are deposited sequentially, and a patterned sacrificial layer is formed by photolithography to define the channels of the logic area and the pixel area. A pre-defined abrasion barrier layer and a first dielectric layer are sequentially deposited on a patterned sacrificial layer, and the first dielectric layer is treated by a chemical mechanical polishing process, with the polishing stopping at the abrasion barrier layer. The excess portion of the polishing barrier layer is removed by an etching process, and only the polishing barrier layer portion below the first dielectric layer after chemical mechanical polishing is retained after the removal process. The pixel area is covered with photoresist, and the channels of the logic area are formed by etching through an etching process. Remove the photoresist covering the pixel area and etch the trenches in the pixel area using an etching process; A second dielectric layer is deposited in the channel of the logic region and the channel of the pixel region, and the second dielectric layer is treated by chemical mechanical polishing process to make the height of the topmost substrate silicon nitride layer of the logic region and the pixel region consistent, thus obtaining a dual shallow channel isolation structure.

2. The method for manufacturing a dual shallow trench separator according to claim 1, characterized in that, The semiconductor substrate is specifically a silicon substrate.

3. The method for manufacturing a dual shallow trench separator according to claim 2, characterized in that, In the step of sequentially depositing a substrate oxide layer, a substrate silicon nitride layer, a sacrificial layer, a bottom anti-reflective coating, and a photoresist, a chemical vapor deposition method is used to deposit a layer of silicon oxide on the surface of the semiconductor substrate as the substrate oxide layer.

4. The method for manufacturing a double shallow trench separator according to claim 3, characterized in that, In the step of sequentially depositing a substrate oxide layer, a substrate silicon nitride layer, a sacrificial layer, a bottom anti-reflective coating, and a photoresist, a chemical vapor deposition method is used to deposit a layer of silicon nitride on the substrate oxide layer as the substrate silicon nitride layer.

5. The method for manufacturing a dual shallow trench separator according to claim 1, characterized in that, In the step of sequentially depositing a substrate oxide layer, a substrate silicon nitride layer, a sacrificial layer, a bottom anti-reflective coating, and a photoresist, the sacrificial layer is deposited on the substrate silicon nitride layer by chemical vapor deposition or physical vapor deposition; wherein the material of the sacrificial layer is polycrystalline silicon or silicon oxide.

6. A method for manufacturing a dual shallow trench barrier according to claim 1 or 5, characterized in that, In the step of forming a patterned sacrificial layer by photolithography... First, a lithography machine is used to expose the designed lithographic pattern onto the photoresist, and an opening or retention area corresponding to the lithographic pattern is formed on the photoresist to form a patterned photoresist. Then, using the patterned photoresist as a mask, the sacrificial layer is etched by dry etching or wet etching to remove the sacrificial layer material below the opening of the photoresist, thus forming a patterned sacrificial layer.

7. A method for manufacturing a dual shallow trench separator according to claim 1, characterized in that, In the steps of covering the pixel area with photoresist and etching to form the channel of the logic area; removing the photoresist covering the pixel area and etching to form the channel of the pixel area again... The pixel area is covered with photoresist, and the film structure of the logic area is etched by dry etching or wet etching. The substrate silicon nitride layer, substrate oxide layer and semiconductor substrate of the logic area are removed in sequence to form the channel of the logic area. The photoresist covering the pixel area is removed to expose the film structure of the pixel area. The film structure of the pixel area is then etched using dry or wet etching methods. The substrate silicon nitride layer, substrate oxide layer, and semiconductor substrate of the pixel area are etched and removed in sequence to form the channel of the pixel area.

8. A method for manufacturing a dual shallow trench separator according to claim 1, characterized in that, The materials of the first dielectric layer and the second dielectric layer are both silicon oxide or silicon oxynitride.

9. A semiconductor structure comprising dual shallow trench isolation, characterized in that, The dual shallow trench isolation is manufactured using the method described in any one of claims 1 to 8.

10. A semiconductor structure according to claim 9, characterized in that, The semiconductor structure is specifically a CMOS image sensor.

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