A method for manufacturing a multi-level non-equal-height structure
By using multi-layer patterned mask layers and multiple etching processes in MEMS device manufacturing, the problem of forming multi-level non-uniform height structures in existing technologies has been solved, achieving manufacturing with reduced process difficulty and diversified structures.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI IND U TECH RES INST
- Filing Date
- 2024-11-28
- Publication Date
- 2026-05-29
AI Technical Summary
In existing MEMS device manufacturing processes, it is difficult to form multi-level non-uniform height structures, and the process is highly dependent on adhesive spraying, which makes the process difficult and makes it hard to form ideal structures.
By sequentially forming multiple patterned mask layers on a substrate, and utilizing the stacking and combination of different mask layers, combined with multiple etching processes, a multi-level non-uniform height structure is formed, and a conventional coating process is used instead of a spray coating process.
It reduces the difficulty of the process, reduces the reliance on the spray adhesive process, and can form non-uniform height structures of three levels or even more, thus simplifying the manufacturing process.
Smart Images
Figure CN122102049A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of microelectromechanical systems, and in particular to a method for manufacturing a multi-level non-uniform height structure. Background Technology
[0002] Some semiconductor devices, especially some microelectromechanical systems (MEMS) devices, such as inertial sensors and pressure sensors, require the fabrication of structures like mass blocks. However, these mass block structures often need to be partially offset from the substrate surface to better fulfill their intended functions. Figure 1 The cross-sectional structure is shown. Therefore, there is an urgent need for a manufacturing method for this type of non-uniform height structure.
[0003] In typical MEMS device manufacturing processes, for Figure 1 The two-level non-uniform height structure shown is typically fabricated by etching, followed by adhesive spraying, exposure, and development. However, existing processes are highly dependent on the adhesive spraying process, which is complex and difficult to manufacture, making it difficult to form the desired non-uniform height structure. Furthermore, existing methods cannot form non-uniform height structures with multiple levels.
[0004] Therefore, it is necessary to provide a preparation method that does not rely on the spray adhesive process and is suitable for forming multi-level non-uniform height structures.
[0005] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application. Summary of the Invention
[0006] The purpose of this invention is to provide a method for manufacturing multi-level non-uniform height structures, so as to obtain a method for preparing non-uniform height structures with low process difficulty and independent of adhesive spraying process.
[0007] To address the aforementioned problems, a manufacturing method for a multi-level non-uniform height structure is provided, comprising the following steps:
[0008] Provide substrate;
[0009] Based on the fact that the silicon structure to be formed in different regions on the substrate has N different heights, N patterned mask layers are sequentially formed on the front side of the substrate, and the number of mask layers stacked on the different regions is determined according to the height of the silicon structure to be formed.
[0010] The mask layer is used as an etching mask to perform N etching operations in sequence. After each etching operation, the mask layer above the area to be etched next is removed.
[0011] Remove the remaining mask layer to obtain the multi-level non-uniform height structure.
[0012] This application's technical solution abandons the traditional approach of first etching grooves to obtain height differences, then spraying adhesive into the grooves to form a mask, and finally etching to obtain the desired silicon structure. Instead, it sequentially forms multiple patterned mask layers on the substrate, utilizing the stacking and combination of different mask layers to define the pattern of multi-level non-uniform height silicon structures. Then, through multiple etching processes—that is, after obtaining a height difference each time, removing a portion of the mask layer to etch the next level of height difference—this process is repeated to obtain multi-level non-uniform height silicon structures. In this application's technical solution, since the thickness of each mask layer is not high during the formation of multiple patterned mask layers, a conventional coating process can be used instead of a spray adhesive process, reducing the process difficulty and dependence on spray adhesive. Furthermore, this solution can form multi-level structures through multiple mask layers, enabling the formation of three or even more levels of non-uniform height structures, representing an improvement over existing technologies.
[0013] In some embodiments, the silicon structure to be formed includes a first-level silicon structure to an Nth-level silicon structure, and the Nth etching process includes: using the mask layer as an etching mask, etching the area not covered by the mask layer, the etching depth being the height of the Nth-level silicon structure; sequentially removing and etching the mask layer above the area of the Nth-level silicon structure to the area of the second-level silicon structure, the etching depth each time being the height difference between two adjacent silicon structures; removing the mask layer above the first-level silicon structure to obtain the multi-level non-uniform height structure.
[0014] In some embodiments, the step of forming a patterned mask layer includes: forming a mask layer on the substrate; forming a photoresist layer on the surface of the mask layer using a coating process; exposing and developing the photoresist layer to obtain a patterned photoresist layer; and using the patterned photoresist layer as an etching mask, patterning the mask layer through an etching process to obtain a patterned mask layer. This method can use a conventional coating process to replace the spray coating process, reducing the process difficulty, reducing dependence on the spray coating process, and ensuring the accuracy of the pattern definition.
[0015] In some embodiments, the substrate is a silicon substrate or an SOI substrate. It is compatible with common semiconductor substrates.
[0016] In some embodiments, a protective layer is formed on the back side of the substrate, the protective layer being an electrostatic film or a dielectric layer. Forming a protective layer can prevent scratches on the substrate and ensure the smooth execution of the process.
[0017] In some embodiments, the etching selectivity ratios of the mask layer and the substrate are different, and the etching selectivity ratios of adjacent mask layers are different. By selecting materials with different etching selectivity ratios, it can be ensured that the remaining structure is not damaged during each etching process, so as to successfully achieve the fabrication of the final structure.
[0018] In some embodiments, the mask layer comprises a silicon oxide layer or a silicon nitride layer. Silicon oxide and silicon nitride layers have relatively high and controllable etch selectivity with silicon materials, and the related processes are mature and have good compatibility.
[0019] In some embodiments, the Nth mask layer is a photoresist mask layer; the step of forming a patterned photoresist mask layer includes: forming a photoresist layer on the surface of the mask layer using a coating process; and exposing and developing the photoresist layer to obtain a patterned photoresist mask layer. Using photoresist as the top layer as the mask can reduce one pattern transfer process and simplify the process.
[0020] In some embodiments, during the etching process, when the mask layer above the substrate is a silicon nitride layer, the etching selectivity ratio between the silicon nitride layer and the substrate is controlled so that the etching of the area not covered by the mask layer is completed while the silicon nitride layer above the substrate is consumed.
[0021] In some embodiments, in the multi-level non-equal height structure, the heights of the first-level silicon structure to the Nth-level silicon structure are respectively the first height to the Nth height, and the first height to the Nth height gradually decrease.
[0022] Compared with the prior art, the beneficial effects of the present invention mainly include the following: In the technical solution of this application, the conventional coating process can be used to replace the spraying process, which reduces the process difficulty, reduces the dependence on spraying operations, and saves the manufacturing processes of spraying, etching, removing adhesive and cleaning; This solution can form multi-level structures through multiple mask layers, and can form three-level or even more-level non-uniform height structures, solving the problem that the existing methods cannot form more-level non-uniform height structures. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the specific embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 This is a schematic diagram of a two-level non-uniform height structure.
[0025] Figure 2This is a flowchart of the preparation process for secondary non-uniform height structures in existing technologies.
[0026] Figure 3 This invention provides a flowchart for the preparation of a secondary non-uniform height structure.
[0027] Figure 4 This is a flowchart of a three-level non-uniform height structure preparation method provided in Embodiment 2 of the present invention.
[0028] Figure 5 This is a flowchart of the preparation process of a three-level non-uniform height structure provided in Embodiment 3 of the present invention. Detailed Implementation
[0029] The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the accompanying drawings. The directional terms mentioned in the following embodiments, such as up, down, left, right, front, or back, are merely for reference to the accompanying drawings. Therefore, the directional terms used are for illustrative purposes and not for limiting the present invention.
[0030] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.
[0031] The fabrication of non-uniform height structures is crucial in some MEMS structures. For example... Figure 1 The diagram shows a cross-sectional view of a secondary non-uniform height structure. It can be observed that a secondary silicon structure 3 is formed in the substrate 1. The height of the secondary silicon structure 3 differs from the surface height of the substrate 1; that is, a portion of the structure in the substrate 1 has a first height (H1 shown in the diagram), while a portion of the secondary silicon structure 3 has a second height (H2 shown in the diagram). Therefore, it is called a secondary non-uniform height structure. The portion with the first height can be referred to as the first-level silicon structure, and the portion with the second height (i.e., the secondary silicon structure 3) can be referred to as the secondary silicon structure.
[0032] It can be understood that when more structures of different heights are formed in substrate 1, it is a multi-level non-uniform height structure. For example, when the structure formed in substrate 1 includes N different heights (N is a positive integer greater than 1), it is an N-level non-uniform height structure. The part with the first height H1 is called the first-level silicon structure, the part with the second height H2 is called the second-level silicon structure, and so on, with the part with the Nth height HN called the Nth-level silicon structure. The height gradually decreases from the first height to the Nth height.
[0033] Figure 2A schematic diagram of the existing process for preparing secondary non-uniform height structures is provided. (Reference) Figure 1 In step a, a substrate 1 is first provided, which is a single-crystal silicon substrate. The substrate 1 has two opposing surfaces, namely a front surface and a back surface. A protective layer 2 is formed on the back surface of the substrate 1. The protective layer 2 can be an attached electrostatic film or a formed dielectric layer (such as an oxide layer, a silicon nitride layer, etc.).
[0034] refer to Figure 2 In step b, the first etching is performed on the front side of substrate 1. The etching depth here is determined based on the difference between the first height and the second height. The etching depth here is usually relatively large and is generally achieved using a deep silicon etching process.
[0035] refer to Figure 2 In step c, a photoresist layer 20 is formed and patterned using a spray coating process. Conventional photolithography can achieve specific patterning on a relatively flat substrate surface. However, in this step, due to the large height difference formed by the first etching, it is difficult to achieve patterning using a conventional coating process. A spray coating process is required to form the patterned photoresist layer 20 on the substrate surface and in the etched grooves. However, the spray coating process in this step is difficult and may result in problems such as difficulty in pattern peeling and severe burrs at the pattern edges, which in turn affect the formation of subsequent secondary non-uniform height structures.
[0036] refer to Figure 2 In the second etching process, d and e are etched using photoresist layer 20 as a mask. The etching depth is the second height. After removing the residual photoresist 20, the final secondary non-uniform height structure can be obtained.
[0037] In existing technologies, the height difference between the first-level silicon structure and the second-level silicon structure is first etched, and then the same depth is etched simultaneously to define the value of the second-level silicon structure.
[0038] The steps in the following embodiments do not correspond one-to-one with the contents of the invention.
[0039] Example 1:
[0040] like Figure 3 The diagram shown is a process flow chart for the fabrication of a secondary non-uniform height structure provided in Embodiment 1 of the present invention.
[0041] refer to Figure 3 To reduce reliance on adhesive spraying, lower process complexity, and support the manufacture of multi-level non-uniform height structures, this invention provides a method for manufacturing multi-level non-uniform height structures. The preparation method includes the following steps:
[0042] Step 1: Provide a substrate 1, and form a first mask layer 30 on the surface of the substrate;
[0043] Specifically, such as Figure 3 In the first embodiment, a substrate 1 is provided. In this embodiment, substrate 1 is a single-crystal silicon substrate. Substrate 1 has two opposing surfaces, namely a front surface and a back surface. A protective layer 2 is formed on the back surface of substrate 1. This protective layer 2 can be an attached electrostatic film or a formed dielectric layer (such as an oxide layer, silicon nitride layer, etc.). It should be noted that, since the secondary non-uniform height structure is formed by etching through substrate 1 in this embodiment, a protective layer 2 needs to be formed on the surface to serve as an etching stop layer and for fixation. In other embodiments, the protective layer 2 may not be formed on the back surface, and this is not limited. In other embodiments, a silicon-on-insulator (SOI) substrate can be used. The SOI substrate consists of a bottom silicon layer, a buried oxide layer, and a top silicon layer from bottom to top. The non-uniform height structure can be fabricated in one of the silicon layers, and the buried oxide layer and the other silicon layer serve as the protective layer 2 of this application.
[0044] First, a mask layer, namely the first mask layer 30, is formed on the front side of the substrate 1. In this embodiment, the first mask layer 30 is a silicon oxide layer. In other embodiments, other materials with different etching selectivity than the silicon substrate can also be used to form the first mask layer, such as a silicon nitride layer or a silicon oxynitride layer. In this embodiment, the formation process of the first mask layer 30 is not limited, and a thermal oxidation process or a vapor deposition process can be used.
[0045] Step 2: Pattern the first mask layer 30;
[0046] Specifically, such as Figure 3 In step b, the first mask layer 30 can be patterned through photolithography and etching processes. Here, the etched window formed after patterning is the maximum outline of the structure. Photolithography and etching for patterning is a prior art technique, which involves forming a photoresist layer on the first mask layer 30, performing exposure and development processes to form a patterned photoresist, and then using etching processes, such as dry etching, to remove the silicon oxide material not protected by the photoresist, transferring the photoresist pattern onto the first mask layer 30 to achieve patterning of the first mask layer 30.
[0047] Step 3: Coat the surface of the substrate 1 and the first mask layer 30 with photoresist to form a photoresist mask layer 31 and pattern it;
[0048] Specifically, such as Figure 3 In step c, a layer of photoresist is coated on the surface of the substrate 1 and the first mask layer 30 to form a photoresist mask layer 31, and then patterned through exposure, development and other processes; it can be understood that the patterned photoresist here includes the substrate 1 above the first mask layer 30 and the substrate 1 where the second-level silicon structure is to be formed.
[0049] It should be noted that, equivalent to the spray coating process used in existing technologies, the photoresist mask layer 31 used to define the silicon structure here can be achieved using a conventional coating process. This is because the thickness of the first mask layer 30 formed on the substrate is relatively low, and a conventional coating process can achieve high-quality patterning.
[0050] At this point, a multilayer patterned mask for defining the secondary non-uniform height structure has been formed. The two patterned masks (i.e., the patterned first mask layer 30 and the photoresist mask layer 31) have overlapping regions. The areas on the substrate 1 covered by the overlapping double masks are used to define the formation of the first-level silicon structure, while the areas covered only by the photoresist mask layer 31 are used to define the formation of the second-level silicon structure.
[0051] Step 4: Perform the first etching based on the height value of the second-level silicon structure;
[0052] Specifically, such as Figure 3 In step d, the first etching is performed using the photoresist mask layer 31 and the first mask layer 30 as etching masks. It can be understood that only the silicon material not covered by the photoresist mask layer 31 or the first mask layer 30 will be etched away at this stage. The depth of the first etching is the height value of the second-level silicon structure, i.e., the second height.
[0053] Step 5: Remove the photoresist and perform a second etching;
[0054] Specifically, such as Figure 3 In step 'e', the residual photoresist mask layer 31 is first removed. Then, using the first mask layer 30 as an etching barrier layer, synchronous etching continues downward to a predetermined depth to form the required secondary non-uniform height structure. It can be understood that the depth of synchronous etching downward here is the difference between the first height and the second height.
[0055] Step 6: Remove the first mask layer 30;
[0056] like Figure 3 By removing the remaining first mask layer 30 from f, the final secondary non-uniform height structure can be obtained.
[0057] Example 2:
[0058] This second embodiment provides a manufacturing method for a three-level non-uniform height structure, the basic idea and steps of which can be referred to in embodiment one. Figure 4 The diagram shown is a process flow chart for the fabrication of a three-level non-uniform height structure provided in Embodiment 2 of the present invention.
[0059] refer to Figure 4 This invention provides a method for manufacturing a multi-level non-uniform height structure, the preparation method comprising the following steps:
[0060] Step 1: Provide a substrate 1, and form a first mask layer 30 on the surface of the substrate;
[0061] This step can refer to step 1 of Example 1, specifically, as follows: Figure 4 In step a, a single-crystal silicon substrate 1 is first provided, and a mask layer, namely the first mask layer 30, is formed on the front side of the substrate 1; in this embodiment, the first mask layer 30 is a silicon oxide layer.
[0062] Step 2: Pattern the first mask layer 30;
[0063] This step can refer to step 2 of Example 1, specifically, as follows: Figure 4 In step b, the first mask layer 30 is patterned. Here, the etched window formed after patterning is the maximum outline of the structure.
[0064] Step 3: Form and pattern the second mask layer 32 on the surfaces of the substrate 1 and the first mask layer 30;
[0065] Specifically, such as Figure 4 As shown in c, a second mask layer 32 is first deposited, and then the deposited second mask layer 32 is patterned. In this embodiment, the second mask layer 32 is a silicon nitride layer; in other embodiments, other material layers can be formed as mask layers. It is understood that adjacent mask layers should be selected with different etching selectivity, so that different height structures can be fabricated by utilizing different selectivity in subsequent etching processes.
[0066] Step 4: Coat the surface of substrate 1 and the second mask layer 32 with photoresist to form a photoresist mask layer 31 and pattern it;
[0067] Specifically, such as Figure 4 In step d, photoresist is coated on the surface of substrate 1 and the second mask layer 32 to form a photoresist mask layer 31, which is then patterned through processes such as exposure and development.
[0068] It should be noted that, equivalent to the spray coating process used in existing technologies, the photoresist mask layer 31 used to define the silicon structure here can be achieved using a conventional coating process. This is because the thickness of the first mask layer 30 and the second mask layer 32 formed on the substrate is relatively low, and a conventional coating process can achieve high-quality patterning.
[0069] At this point, a multi-layer patterned mask for defining the three-level non-uniform height structure has been formed. The three patterned masks (i.e., the patterned first mask layer 30, the second mask layer 32, and the photoresist mask layer 31) have overlapping regions. The areas on the substrate 1 covered by the overlapping three mask layers are used to define the formation of the first-level silicon structure, the areas on the substrate 1 covered by the overlapping two mask layers are used to define the formation of the second-level silicon structure, and the areas covered by only one mask layer are used to define the formation of the third-level silicon structure.
[0070] Step 5: Perform the first etching based on the height value of the third-level silicon structure;
[0071] Specifically, such as Figure 4 In step 'e', the first etching is performed using photoresist mask layer 31, second mask layer 32, and first mask layer 30 as etching masks. It can be understood that only the silicon material not covered by the mask will be etched away at this stage. The depth of the first etching is the height value of the third-level silicon structure, i.e., the third height.
[0072] Step 6: Sequentially remove the second mask layer 32 and photoresist from the areas not covered by photoresist, and perform a second etching;
[0073] Specifically, such as Figure 4 In steps f and g, the second mask layer 32, which is not covered with photoresist, is first removed, followed by the removal of any remaining photoresist. Then, using the second mask layer as an etching barrier, simultaneous etching continues downwards to a predetermined depth, forming a secondary non-uniform height structure. It can be understood that the depth of simultaneous downward etching here is the difference between the second and third heights.
[0074] Step 7: Remove the remaining second mask layer 32 and perform a third etching;
[0075] Specifically, such as Figure 4 In step h, the remaining second mask layer 32 is first removed. Then, using the first mask layer 30 as an etching barrier layer, synchronous etching continues downward to a predetermined depth to form the required three-level non-uniform height structure. It can be understood that the depth of synchronous etching downward here is the difference between the first height and the second height.
[0076] Step 8: Remove the remaining first mask layer 30;
[0077] like Figure 4 In step i, the remaining first mask layer 30 is removed to obtain the final three-level non-uniform height structure. The first-level silicon structure has a first height, the second-level silicon structure 3 has a second height, and the third-level silicon structure 4 has a third height.
[0078] Example 3:
[0079] This third embodiment is an improvement upon the second embodiment, and its basic ideas and steps can be referred to those described in the second embodiment. Figure 5 The diagram shown is a process flow chart for the fabrication of a three-level non-uniform height structure provided in Embodiment 3 of the present invention.
[0080] refer to Figure 5 This invention provides a method for manufacturing a multi-level non-uniform height structure, the preparation method comprising the following steps:
[0081] Step 1: Provide a substrate 1, and form a first mask layer 30 on the surface of the substrate;
[0082] like Figure 5 For step 'a' in this example, please refer to step 1 of Example 2.
[0083] Step 2: Pattern the first mask layer 30;
[0084] like Figure 5 For step b in this example, please refer to step 2 of Example 2.
[0085] Step 3: Form and pattern the second mask layer 32 on the surfaces of the substrate 1 and the first mask layer 30;
[0086] like Figure 5 For step c, please refer to step 3 of Example 2.
[0087] Step 4: Coat the surface of substrate 1 and the second mask layer 32 with photoresist to form a photoresist mask layer 31 and pattern it;
[0088] like Figure 5 For step d in Example 2, please refer to step 4.
[0089] Step 5: Perform the first etching based on the height value of the third-level silicon structure;
[0090] Specifically, such as Figure 5 In step 'e', the first etching is performed using photoresist mask layer 31, second mask layer 32, and first mask layer 30 as etching masks. It can be understood that only the silicon material not covered by the mask will be etched away at this stage. The depth of the first etching is the height value of the third-level silicon structure, i.e., the third height.
[0091] Step 5 differs from step 5 in Embodiment 2. In this embodiment, the etching selectivity ratio of silicon nitride to bulk silicon can be adjusted. By utilizing the proportional relationship between their etching rates, the second mask layer 32, which is not covered by photoresist, is completely consumed when the silicon etching depth reaches a predetermined depth (i.e., the third height). Thus, during subsequent etching, it is unnecessary to perform the step of removing the second mask layer 32 that is not covered by photoresist.
[0092] Step 6: Remove the photoresist and perform a second etching;
[0093] In this step, such as Figure 5 In step f, since the second mask layer 32, which is not covered by photoresist, has been consumed, only the residual photoresist mask 31 needs to be removed. Then, using the second mask layer as an etching barrier, synchronous etching continues downward to a predetermined depth to form a secondary non-uniform height structure. It can be understood that the depth of synchronous etching downward here is the difference between the second height and the third height.
[0094] Step 7: Remove the remaining second mask layer 32 and perform a third etching;
[0095] like Figure 5 For step g, please refer to step 7 of Example 2.
[0096] Step 8: Remove the remaining first mask layer 30;
[0097] like Figure 5 In step h, this step can refer to step 8 of embodiment 2 to remove the residual first mask layer 30 and obtain the final three-level non-uniform height structure.
[0098] The above embodiments illustrate the fabrication processes of two-level and three-level non-uniform height structures. This method can also be used to fabricate structures with more levels. The fabrication process for more levels of non-uniform height structures is similar to that of three-level structures, and so on. For example, for an N-level non-uniform height structure, N patterned mask layers can be sequentially formed on the surface of substrate 1. The materials of adjacent mask layers are materials with different etching selectivity ratios, and all mask layers must have a larger etching selectivity ratio than the silicon substrate. It is understood that mask layer patterning typically requires photolithography and etching processes. Therefore, the last mask layer (i.e., the Nth mask layer) can directly use photoresist as the mask layer, reducing one pattern transfer process. For the above N mask layers, the fabrication of silicon structures of different levels is achieved by overlapping different mask layers. That is, the number of mask layers to be stacked in different regions is determined according to the height of the silicon structure to be formed in different regions of the substrate. It is understood that the higher the height of the silicon structure to be formed, the fewer etching steps are required. For an N-level non-uniform height structure, a total of N etching operations are required to define N heights. Areas not covered by any mask layer will be etched N times, areas covered by only one mask layer will be etched N-1 times, and so on. Areas covered by N mask layers will not be etched, thus forming N different heights, which is the required N-level non-uniform height structure.
[0099] The method provided in this application can form a two-level or even multi-level non-equal height structure, which is very beneficial for the processing and manufacturing of various inertial and pressure sensor structures. Furthermore, by changing the process flow, conventional adhesive coating process can be used to replace the existing adhesive spraying operation, saving the manufacturing processes of adhesive spraying, etching, adhesive removal and cleaning.
[0100] The common English terms or letters used in this invention for clarity of description are for illustrative purposes only and are not limiting interpretations or specific uses. They should not be used to limit the scope of protection of this invention based on their possible Chinese translations or specific letters.
[0101] It should also be noted that in this article, relational terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations.
Claims
1. A method for manufacturing a multi-level non-uniform height structure, characterized in that, Includes the following steps: Provide substrate; Based on the fact that the silicon structure to be formed in different regions on the substrate has N different heights, N patterned mask layers are sequentially formed on the front side of the substrate, and the number of mask layers stacked on the different regions is determined according to the height of the silicon structure to be formed. The mask layer is used as an etching mask to perform N etching operations in sequence. After each etching operation, the mask layer above the area to be etched next is removed. Remove the remaining mask layer to obtain the multi-level non-uniform height structure.
2. The manufacturing method of a multi-level non-uniform height structure according to claim 1, characterized in that, The silicon structure to be formed includes a first-level silicon structure to an Nth-level silicon structure, and the Nth etching process includes: Using the mask layer as an etching mask, the area not covered by the mask layer is etched, and the etching depth is the height of the Nth level silicon structure; The mask layer above the region of the Nth level silicon structure to the region of the second level silicon structure is removed and etched sequentially, with the depth of each etching being the height difference between the two adjacent silicon structures. The mask layer above the first-level silicon structure is removed to obtain the multi-level non-uniform height structure.
3. The manufacturing method of a multi-level non-uniform height structure according to claim 1, characterized in that, The steps for forming a patterned mask layer include: A mask layer is formed on the substrate; A photoresist layer is formed on the surface of the mask layer using a coating process; The photoresist layer is exposed and developed to obtain a patterned photoresist layer. Using a patterned photoresist layer as an etching mask, the mask layer is patterned through an etching process to obtain a patterned mask layer.
4. The manufacturing method of a multi-level non-uniform height structure according to claim 1, characterized in that, The substrate is a silicon substrate or an SOI substrate.
5. The manufacturing method of a multi-level non-uniform height structure according to claim 1, characterized in that, A protective layer is formed on the back side of the substrate, which is an electrostatic film or a dielectric layer.
6. The manufacturing method of a multi-level non-uniform height structure according to claim 1, characterized in that, The etching selectivity ratios of the mask layer and the substrate are different, and the etching selectivity ratios of adjacent mask layers are different.
7. The manufacturing method of a multi-level non-uniform height structure according to claim 6, characterized in that, The mask layer includes a silicon oxide layer or a silicon nitride layer.
8. The manufacturing method of a multi-level non-uniform height structure according to claim 6, characterized in that, The Nth mask layer is a photoresist mask layer; The steps for forming a patterned photoresist mask layer include: A photoresist layer is formed on the surface of the mask layer using a coating process; The photoresist layer is exposed and developed to obtain a patterned photoresist mask layer.
9. The manufacturing method of a multi-level non-uniform height structure according to claim 7, characterized in that, During the etching process, when the mask layer above the substrate is a silicon nitride layer, the etching selectivity ratio between the silicon nitride layer and the substrate is controlled so that the etching of the area not covered by the mask layer is completed while the silicon nitride layer above the substrate is consumed.
10. A method for manufacturing a multi-level non-uniform height structure according to claim 2, characterized in that, In the multi-level non-uniform height structure, the heights of the first-level silicon structure to the Nth-level silicon structure are respectively the first height to the Nth height, and the heights of the first height to the Nth height gradually decrease.