Suspension beam structure of semiconductor device and manufacturing method thereof
By using a one-step etching process in the manufacturing of suspended beam structures of semiconductor devices, the substrate is etched at an angle, and the problems of complex and high cost in the prior art are solved, and process simplification and cost reduction are achieved.
Patent Information
- Application Number
- CN202311097439.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-28
- Publication Date
- 2025-03-04
AI Technical Summary
The manufacturing process of hanging beam structures of existing semiconductor devices requires 2 steps of etching, resulting in complex processes, high cost, and frequent cleaning steps that increase manufacturing costs.
The 1-step etching process is used to etch the substrate sideways downward by tilting a certain angle to form a hanging beam structure, avoiding multi-step etching and cleaning steps.
The process flow is simplified, manufacturing costs are reduced, and the mass production efficiency and yield of semiconductor device manufacturing is improved.
Smart Images
Figure CN119560378A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of semiconductor devices, and in particular to a method for manufacturing a cantilever beam structure of a semiconductor device. Background Art
[0002] In the existing semiconductor device manufacturing process, in order to connect the bottoms of two adjacent deep silicon trenches and form a cantilever structure, the conventional solution requires two steps of etching. Figure 1 As shown, the step of etching on the substrate to form the cantilever beam 6 is separated by the step of depositing the dielectric layer 4 as a protective layer for the cantilever beam and is divided into two steps, namely, the first step of etching: forming a deep silicon trench with a vertical angle; the second step of etching: isotropic dry etching with a high selectivity ratio for silicon oxide on the bottom sidewall surface of the deep silicon trench, pushing and completely consuming the bottom sidewalls of two adjacent deep silicon trenches and connecting them. Specifically, as Figure 1 Steps (1) to (5) include the following steps: (1) forming a hard mask 2 including a first through hole and a second through hole on a substrate 1; (2) forming a first deep silicon trench 3 and a second deep silicon trench 3 at a vertical angle; (3) depositing a dielectric layer 4 on the surface of the first deep silicon trench 3 and the second deep silicon trench 3 to protect the portion between the first deep silicon trench 3 and the second deep silicon trench 3 in subsequent etching to form a cantilever beam 6; (4) carving the dielectric layer 4 on the surface of the first deep silicon trench 3 and the second deep silicon trench 3, and continuing to etch downward for a certain distance to form a cavity 5. (5) pushing and completely consuming the bottom sidewalls of two adjacent deep silicon trenches so that the two cavities 5 are connected, thereby forming a cantilever beam 6.
[0003] In this process, for example, impurities or by-products may be formed during etching in steps (2), (4), and (5), and impurities may also be introduced or by-products may be formed during deposition to form a dielectric layer in step (3). These impurities or by-products greatly affect the yield of the process. In order to ensure the yield of the process, the existing process requires cleaning the device after each step is completed, and the impurities or by-products are removed by a wet cleaning process. However, frequent cleaning greatly increases the cost of the process. At the same time, step-by-step etching is not conducive to reducing manufacturing costs. Summary of the invention
[0004] Based on the problems described above, the present invention proposes a cantilever beam structure of a semiconductor device and a manufacturing method thereof. The cantilever beam can be formed by adopting only one etching process. Compared with the existing manufacturing method, it not only reduces one etching process step, but also avoids complicated process cleaning steps, greatly simplifies the process, reduces process costs, and thus reduces the mass production cost of semiconductor device manufacturing.
[0005] In a first aspect, a method for manufacturing a cantilever beam structure of a semiconductor device of the present invention comprises the steps of: S1: providing a silicon wafer as a substrate, and preparing a hard mask including a first through hole and a second through hole on the substrate by using a groove forming mask; S2: According to the positions of the first through hole and the second through hole, the substrate is laterally etched downward in a direction inclined at a certain angle toward both sides of the first through hole and the second through hole, respectively, to form the cantilever beam.
[0006] In a specific embodiment, the step S2 specifically further includes: first etching vertically downward for a first time, then etching in a direction inclined at a certain angle to both sides for a second time, and then etching vertically downward for a third time.
[0007] In a specific embodiment, in the step S2: after vertically etching downward for a first time, a first groove and a second groove are formed on the surface of the substrate, and a silicon polymer layer is formed on the surfaces of the first groove and the second groove.
[0008] In a specific embodiment, the silicon polymer layer is formed by combining a gas containing C / F / S elements and an etching product.
[0009] In a specific embodiment, the first time and the second time are much smaller than the third time.
[0010] In a specific embodiment, the first time includes 1 to 15 s, the second time includes 1 to 15 s, and the third time includes 0.5 to 15 minutes.
[0011] In a specific embodiment, the angle is greater than zero and less than 90°.
[0012] In a specific embodiment, the angle comprises 1°, or 10°.
[0013] In a specific embodiment, the method further includes the steps of: S3: performing epitaxial growth on the outer side of the cantilever beam to form an epitaxial growth layer; S4: performing self-aligned etching on the epitaxial growth layer using the hard mask, and etching the remaining epitaxial growth layer to form a part of the cantilever beam.
[0014] In a second aspect, the present invention further provides a semiconductor device having a cantilever structure, wherein the cantilever structure is manufactured by the method described in any of the aforementioned embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The accompanying drawings of the present invention constitute a part of this specification and are used to further understand the present invention. The drawings illustrate embodiments of the present invention and together with the description are used to explain the principle of the present invention.
[0016] Figure 1The present invention is a flow chart of a method for manufacturing a cantilever beam structure of an existing semiconductor device.
[0017] Figure 2 The present invention is a flowchart of a method for manufacturing a cantilever structure of a semiconductor device according to an embodiment of the present invention. DETAILED DESCRIPTION
[0018] The following detailed descriptions are all illustrative and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.
[0019] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention.
[0020] In a first aspect, an embodiment of the present invention provides a process flow chart of one embodiment of a method for manufacturing a cantilever beam structure of a semiconductor device. The process flow chart includes the following steps: S1: A silicon wafer is provided as a substrate 1, and a hard mask including a first through hole and a second through hole is prepared on the substrate by using a groove forming mask; for details, see the attached Figure 2 As shown in FIG. 1 (a), a hard mask 2 is pre-formed on a substrate 1, and a groove forming mask is formed on the hard mask 2. A first through hole H1 and a second through hole H2 are formed on the hard mask 2 using the groove forming mask, and the surface of the silicon wafer is exposed through the first through hole H1 and the second through hole H2.
[0021] S2: According to the positions of the first through hole H1 and the second through hole H2, the substrate 1 is etched downward at a certain angle to form a cantilever beam 6. Figure 2 As shown in FIG. (b), in the first through hole H1 and the second through hole H2, the exposed silicon wafer surface is etched at a certain angle to form a cantilever beam 6, and the etching direction has an intersection point below the cantilever beam 6. Therefore, the cantilever beam 6 can be directly hollowed out by side etching to form a cavity 5. In this embodiment, the cantilever beam 6 is manufactured by applying one step of etching to the substrate 1. This process is relatively simple. Figure 1 The illustrated prior art process not only omits steps (2)-(4), but also omits the cleaning step required in the steps (2)-(4) process, thereby simplifying the process and greatly reducing the manufacturing cost of the process.
[0022] In a specific embodiment, the etching process of step S2 includes: first etching vertically downward for a first time, then etching in a direction inclined at a certain angle to both sides for a second time, and then etching vertically downward for a third time. Preferably, the third time is much longer than the first time and the second time, for example, the first time is preferably 1-15 s, the second time is preferably 1-15 s, and the third time is preferably 0.5min-15min; through this time setting, most of the cantilever beam structure sizes suitable for semiconductor devices can be made in batches in one step, and this time setting will not cause situations such as collapse, over-etching, under-etching, etc. during the etching process, especially, it can make part or all of the cantilever beam structure size and shape suitable for placing field effect transistors, which can greatly improve the process yield of semiconductor devices. However, the setting of the first time, the second time, and the third time is not limited to this, and the length of the first time, the second time, and the third time can be reasonably designed according to the size of the cantilever beam, so that the shape or size of the cantilever beam structure can meet different production needs.
[0023] In a specific embodiment, in step S2: after the substrate 1 is etched vertically downward for a first time, a first groove and a second groove having a certain depth are correspondingly formed on the surface of the substrate, and a silicon polymer layer is formed on the surface of the first groove and the second groove. The silicon polymer layer is an anti-corrosion film formed on the side wall, which can protect the cantilever beam during subsequent lateral etching (inclined at a certain angle), because the silicon polymer can block the etching of the side wall and enhance the directionality of the etching, thereby achieving good control of the key dimensions of the pattern. Among them, the silicon polymer layer is formed by combining a gas containing C / F / S elements (such as etching gas C2F4) and an etching product after etching to form the first groove and the second groove. Since the etching product needs to be used to generate a silicon polymer layer for cantilever beam protection, there is no need to add a cleaning step, nor is it necessary to divide the etching to form the cantilever beam into two steps, and only one step is required to complete it, so when it is divided into two steps, the cleaning step corresponding to each step can also be omitted. Compared with the prior art which requires deliberately adding steps to form a dielectric layer of materials such as silicon nitride as a protective layer, this process reduces the etching steps, reduces the steps of depositing the dielectric layer, and also reduces the corresponding multiple cleaning steps, thereby greatly simplifying the process and significantly reducing manufacturing costs.
[0024] In a specific embodiment, the inclination angle to both sides needs to be larger than the angle during vertical downward etching, that is, the inclination angle is greater than zero, that is, the angle relative to the horizontal plane of the substrate surface is greater than 90°, and the preferred angle range is greater than zero and less than 180° (that is, the inclination angle is greater than zero and less than 90°, with the direction of the vertical horizontal plane as the inclination reference direction), for example, 91°, 100° (that is, inclination 1°, 10° on both sides), but the range of the inclination angle in this embodiment is not limited to this, as long as the angle can hollow out the part below the cantilever beam after inclination, it is within the protection scope of the present invention.
[0025] In a specific embodiment, in order to further improve the yield of the cantilever beam 6, the following steps are specifically included: S3: epitaxial growth is performed on the outer side of the cantilever beam to form an epitaxial growth layer 7. Specifically, as shown in the attached Figure 2 As shown in FIG (c), the use of epitaxial growth technology can be grown on the wall of the hollow cavity 5 of an epitaxial growth layer 7; S4: Use the hard mask 2 to perform self-aligned etching on the epitaxial growth layer 7, and the remaining epitaxial growth layer 7 etched outside the cantilever beam 6 is used to form a part of the cantilever beam. Specifically, the pattern of the hard mask 2 can be used to remove the irregular part of the periphery of the epitaxial growth layer 7, and the remaining part of the epitaxial growth layer 7 is used to form the cantilever beam, as shown in the attached Figure 2 As shown in Figure (d), a regular cantilever with ideal size is formed, especially the outer surface of the bottom end of the cantilever is relatively smoother. The smooth bottom end is beneficial to the improvement of the electrical performance of the semiconductor devices subsequently manufactured. For example, the regular cantilever can improve the yield of semiconductor devices such as field effect transistors formed subsequently.
[0026] In a second aspect, the present invention provides a semiconductor device with a cantilever structure, wherein the cantilever structure is manufactured by the method mentioned in any of the above embodiments.
[0027] The present invention proposes a cantilever beam structure of a semiconductor device and a manufacturing method thereof, which adopts a one-step etching process to form the cantilever beam. Compared with the existing manufacturing method, it not only reduces the etching process by one step, but also avoids complicated process cleaning steps, greatly simplifies the process, reduces the process cost, and thus reduces the mass production cost of semiconductor device manufacturing.
[0028] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of the present invention. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and corrections to the present invention. Such modifications, improvements and corrections are suggested in the present invention, so such modifications, improvements and corrections still belong to the spirit and scope of the exemplary embodiments of the present invention.
[0029] It should be understood that the embodiments described in the present invention are only used to illustrate the principles of the embodiments of the present invention. Other variations may also fall within the scope of the present invention. Therefore, as examples and not limitations, alternative configurations of the embodiments of the present invention may be considered consistent with the teachings of the present invention. Accordingly, the embodiments of the present invention are not limited to the embodiments explicitly introduced and described in the present invention.
Claims
1. A method for manufacturing a cantilever beam structure of a semiconductor device, characterized in that: The method comprises the steps of: S1: providing a silicon wafer as a substrate, and preparing a hard mask including a first through hole and a second through hole on the substrate by using a groove forming mask; S2: According to the positions of the first through hole and the second through hole, the substrate is laterally etched downward in a direction inclined at a certain angle toward both sides of the first through hole and the second through hole, respectively, to form the cantilever beam.
2. The method for manufacturing a cantilever beam structure of a semiconductor device according to claim 1, characterized in that: The step S2 specifically includes: first etching vertically downward for a first time, then etching in a direction inclined to both sides at a certain angle for a second time, and then etching vertically downward for a third time.
3. The method for manufacturing a cantilever beam structure of a semiconductor device according to claim 2, characterized in that: In the step S2: after vertically etching downward for a first time, a first groove and a second groove are formed on the surface of the substrate, and a silicon polymer layer is formed on the surfaces of the first groove and the second groove.
4. The method for manufacturing a cantilever beam structure of a semiconductor device according to claim 3, characterized in that: The silicon polymer layer is formed by combining a gas containing C / F / S elements and an etching product.
5. The method for manufacturing a cantilever beam structure of a semiconductor device according to claim 2, characterized in that: The first time and the second time are much shorter than the third time.
6. The method for manufacturing a cantilever beam structure of a semiconductor device according to claim 5, characterized in that: The first time includes 1~15s, the second time includes 1~15s, and the third time includes 0.5~15min.
7. The method for manufacturing a cantilever beam structure of a semiconductor device according to claim 2, characterized in that: The angle is greater than zero and less than 90°.
8. The method for manufacturing a cantilever beam structure of a semiconductor device according to claim 7, characterized in that: The angle includes 1°, or 10°.
9. The method for manufacturing a cantilever beam structure of a semiconductor device according to claim 1, characterized in that: The specific steps include: S3: performing epitaxial growth on the outer side of the cantilever beam to form an epitaxial growth layer; S4: performing self-aligned etching on the epitaxial growth layer using the hard mask, and etching the remaining epitaxial growth layer to form a part of the cantilever beam.
10. A semiconductor device having a cantilever beam structure, characterized in that: The cantilever beam structure is made by the method described in any one of claims 1-9.