A semiconductor device and a manufacturing method thereof

Abstract

The application discloses a semiconductor device and a manufacturing method thereof. The manufacturing method of the semiconductor device comprises the following steps: firstly, growing a second material in a trench etched in a first material; then, etching the second material on the sidewall of the trench and reserving the second material on the bottom of the trench; and finally, processing the sidewall of the trench by a first process, so that the first material on the sidewall of the trench is converted into a third material, and the first material on the bottom of the trench is not converted into the third material, and an opening is formed or the opening is covered with the second material or a fourth material different from the third material. Thus, the semiconductor device with the sidewall of the trench and the bottom of the trench made of different materials can be obtained without using a special etching (ET) machine to etch the bottom of the trench, so that the manufacturing process and the process difficulty are greatly simplified, and the manufacturing equipment cost is greatly saved.

Description

Technical Field

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

[0002] In certain specialized semiconductor devices, it is required that the sidewalls of some trenches in the device be made of one material, while the bottom of the trench is open, or made of another material.

[0003] For example, in BCD / DMOS, in order to isolate the latch-up effect that may be caused by parasitic NPN / PNP BJTs, the sidewalls of the trench are required to be isolated using a dielectric layer material (e.g., oxide); however, in order to ensure that the doped electrode pillars (D-Poly) are grounded, the bottom of the trench is required to be open (without using the dielectric layer material used for the sidewalls).

[0004] Currently, most solutions use special etching (ET) equipment to etch the bottom of the trench while preserving the sidewall dielectric layer material, thus creating an open bottom.

[0005] However, this special etching (ET) equipment is expensive and increases manufacturing costs; in addition, for some deep and narrow trenches, the use of etching equipment will inevitably damage the sidewalls of the trenches, causing quality defects. Summary of the Invention

[0006] In response to the aforementioned technical problems, the applicant has creatively provided a semiconductor device and a method for manufacturing the same.

[0007] According to a first aspect of the present application, a method for manufacturing a semiconductor device is provided. The method includes: growing a first material; etching a groove in the first material to obtain a trench; growing a second material in the trench; etching away the second material on the sidewall of the trench to expose the first material on the sidewall of the trench, and retaining a portion of the second material at the bottom of the trench (102); and processing the first material exposed on the sidewall of the trench using a first process to transform the first material exposed on the sidewall of the trench into a third material; wherein the portion of the second material at the bottom of the trench is used to prevent the first material at the bottom of the trench from being transformed into a third material by the first process.

[0008] According to one embodiment of this application, the second material includes any of the following materials: a material that will dissolve after being processed by the first process; a material that will be transformed into a trench to be filled after being processed by the first process; a material that will not change after being processed by the first process; or a material that will be transformed into a fourth material after being processed by the first process, the fourth material being a material intended to cover the bottom of the trench.

[0009] According to one embodiment of this application, the first process includes a thermal oxidation process.

[0010] According to one embodiment of this application, the thermal oxidation process includes a furnace tube thermal oxidation process.

[0011] According to one embodiment of this application, the temperature of the thermal oxidation process is lower than the minimum temperature at which the second material is thermally oxidized.

[0012] According to one embodiment of this application, growing a second material in a trench includes: using a physical vapor deposition process to grow the second material in the trench.

[0013] According to one embodiment of this application, in the process of growing a second material in a trench using a physical vapor deposition process, the manufacturing method further includes: controlling the time of the physical vapor deposition process and / or the amount of material deposited, so that the thickness difference between the second material grown on the sidewall of the trench and the second material grown on the bottom of the trench is greater than or equal to a thickness difference threshold.

[0014] According to one embodiment of this application, etching away the second material on the sidewalls of the trench and retaining the second material at the bottom of the trench includes: using a wet etching process to etch away the second material on the sidewalls of the trench and retain the second material at the bottom of the trench.

[0015] According to one embodiment of this application, in the process of etching away the second material on the trench sidewalls using a wet etching process, the manufacturing method further includes: controlling the time of the wet etching process to ensure that the second material on the trench sidewalls is completely etched away, while retaining a portion of the second material at the bottom of the trench.

[0016] According to a second aspect of the present application, a semiconductor device is provided, the semiconductor device including a trench etched in a first material, the sidewalls of the trench being covered with a third material; the bottom of the trench is not covered with the third material to form an opening, or is covered with a fourth material; wherein the third material is obtained by converting the first material after a first process and the surface of the third material has no traces of etching.

[0017] This application discloses a semiconductor device and its manufacturing method. The manufacturing method includes: first, growing a second material within a trench obtained by etching a first material; then, etching away the second material on the sidewalls of the trench while retaining the second material at the bottom of the trench; subsequently, performing a first process on the sidewalls of the trench, transforming the first material on the sidewalls into a third material, while the first material at the bottom of the trench does not transform into the third material, forming an opening or being covered by a second or fourth material different from the third material. In this way, a semiconductor device with different materials on the sidewalls and bottom of the trench can be obtained without using a special etching (ET) machine to etch the bottom of the trench, greatly simplifying the manufacturing process and reducing the complexity of the process, and also significantly saving on manufacturing equipment costs.

[0018] It should be understood that the implementation of the embodiments of this application does not need to achieve all the above-mentioned beneficial effects, but a specific technical solution can achieve a specific technical effect, and other implementation methods of the embodiments of this application can also achieve beneficial effects not mentioned above. Attached Figure Description

[0019] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings. Several embodiments of this application are illustrated in the drawings by way of example and not limitation, in which:

[0020] In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

[0021] Figure 1 One of the schematic cross-sectional views of the semiconductor device structure to which the semiconductor device manufacturing method of this application applies is shown;

[0022] Figure 2 This is a second schematic cross-sectional view of the semiconductor device structure to which the semiconductor device manufacturing method of this application applies.

[0023] Figure 3 A schematic flowchart illustrating a method for manufacturing a semiconductor device according to an embodiment of this application is shown;

[0024] Figure 4 This shows one of the structural cross-sectional schematic diagrams of a certain stage in the semiconductor device manufacturing method of this application;

[0025] Figure 5 This is shown as a second schematic cross-sectional view of a certain stage in the semiconductor device manufacturing method of this application;

[0026] Figure 6 This is the third schematic diagram of a structural cross-section of a certain stage in the semiconductor device manufacturing method of this application;

[0027] Figure 7 A schematic flowchart illustrating another embodiment of the semiconductor device manufacturing method of this application is shown.

[0028] Attachment part number explanation:

[0029] 101 – First Material;

[0030] 102 – Second Material;

[0031] 103 – Third Material;

[0032] 104 – Fourth Material. Detailed Implementation

[0033] To make the objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0034] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0036] In order to describe the three-dimensional structure of semiconductor devices from multiple perspectives, this application refers to the structural schematic diagram obtained by vertically cutting the semiconductor device as a structural cross-sectional schematic diagram; and the structural schematic diagram obtained by horizontally cutting the semiconductor device as a structural section schematic diagram.

[0037] Figure 1 A semiconductor device that can be manufactured using the semiconductor device manufacturing method of this application is shown. For example... Figure 1 As shown, the semiconductor device includes a trench etched in a first material 101, the sidewalls of the trench being covered with a third material 103, and the bottom of the trench not covered with the third material 103, forming an opening.

[0038] Figure 2 Another semiconductor device that can be manufactured using the semiconductor device manufacturing method of this application is shown. For example... Figure 2 As shown, the semiconductor device includes a trench etched in a first material 101, the sidewalls of the trench being covered with a third material 103, and the bottom of the trench not being covered with the third material 103 but with a fourth material 104, wherein the fourth material 104 is different from the third material 103.

[0039] In existing technologies, manufacturing Figure 1 or Figure 2 The semiconductor devices shown are mostly manufactured using the following method: growing a first material 101; etching trenches within the first material 101 to obtain trenches; growing a third material 103 within the trenches; and then, using a special ET machine, etching away the third material 103 at the bottom of the trenches while retaining the third material 103 on the sidewalls. If manufacturing... Figure 2 The semiconductor device shown also requires the growth of a fourth material 104 at the bottom of the trench.

[0040] Manufacturing using the above process Figure 1 or Figure 2 The semiconductor device shown requires the purchase of a special ET machine, which is currently quite expensive. Furthermore, during the ET machine's etching process of removing the third material 103 from the bottom of the trench, it inevitably affects the third material 103 on the trench sidewalls, causing the thickness and quality of the third material 103 on the sidewalls to fail to meet specific requirements.

[0041] Therefore, this application provides a method for manufacturing a semiconductor device, such as... Figure 3 As shown, the manufacturing method includes:

[0042] Step S310: Grow the first material 101.

[0043] The first material 101 can be grown using any growth process suitable for the first material 101, such as physical vapor deposition (PVD), chemical vapor deposition (CVD), or atomic layer deposition (ALD).

[0044] Step S320: Grooves are cut into the first material 101 to obtain grooves, such as... Figure 4 As shown.

[0045] The grooves in the first material 101 can be made using any etching process suitable for the first material 101, such as dry etching, wet etching, or photolithography.

[0046] Step S330: A second material 102 is grown in the trench to obtain the following... Figure 5 The structure shown.

[0047] The second material 102 is different from the first material 101.

[0048] In addition, such as Figure 5 As shown, to grow the second material 102 in the trench, the thickness difference between the second material 102 on the sidewall of the trench and the second material 102 on the bottom of the trench must be greater than or equal to the thickness difference threshold.

[0049] The thickness difference between the second material 102 on the trench sidewall and the second material 102 on the bottom of the trench is greater than or equal to the thickness difference threshold. This ensures that when the second material 102 on the trench sidewall is etched later, a portion of the second material 102 on the bottom of the trench can still be retained, and that enough second material 102 is retained so that the first material 101 at the bottom of the trench is not exposed and oxidized into the third material 103 by the thermal oxidation process.

[0050] The thickness difference threshold here can be set by domain experts based on experience; or it can be obtained and set through multiple experiments.

[0051] In this embodiment, the specific process for growing the second material 102 is not limited, as long as the above-mentioned effect can be achieved.

[0052] Step S340: Etch away the second material 102 on the trench sidewall to expose the first material 101 on the trench sidewall, and retain a portion of the second material 102 at the bottom of the trench, to obtain... Figure 6 The structure shown.

[0053] When etching away the second material 102 on the sidewalls of the trench while retaining a portion of the second material 102 at the bottom of the trench, any etching method suitable for the second material 102 can be used. For example, dry etching, wet etching, or photolithography.

[0054] In step S350, using the first process, the first material 101 exposed on the trench sidewall is processed to transform the first material 101 exposed on the trench sidewall into a third material 103, resulting in... Figure 2 or Figure 1 The structure shown.

[0055] The first material 101 is a material that can be transformed into the third material 103 through the first process. Therefore, the selection of the first material 101 often depends on the first process and the third material 103 that needs to be transformed.

[0056] The first process is a manufacturing process that can chemically transform the first material 101 into the third material 103, such as a thermal oxidation process or a nitriding process.

[0057] Assuming the semiconductor device to be manufactured requires the formation of a nitride thin film on the trench sidewalls, and the manufacturer determines the first process to be a nitriding process and the third material 103 to be silicon nitride, then theoretically any material that can be converted into silicon nitride by the nitriding process can be used as the first material 101. The implementer can also determine the first material 101 based on other implementation requirements. For example, if the layer containing the first material 101 is a conductive layer, then the first material 101 needs to be both conductive and convertible into silicon nitride by the nitriding process.

[0058] The second material 102 at the bottom of the trench is used to prevent the first material 101 at the bottom of the trench from being transformed into the third material 103 by the first process. Thus, after the first process is completed, the first material 101 on the trench sidewall is transformed into the third material 103, but the first material 101 at the bottom of the trench remains unchanged, thereby obtaining... Figure 1 or Figure 2 The semiconductor device shown.

[0059] The selection of the second material 102 often depends on the first process and the structural requirements of the product. For example, if it is necessary to manufacture... Figure 1 The semiconductor device shown is then:

[0060] The second material 102 can be a material that will melt away after being processed by the first process. Thus, after the first process is completed, the second material 102 melts away, yielding... Figure 1 The semiconductor device shown.

[0061] The second material 102 can also be a material that, after being processed by the first process, will be transformed into the material to be filled in the trench. Thus, after the trench filling material forms a device, the second material 102 integrates with the trench filling material, becoming part of the device, thereby creating an opening at the bottom of the trench, and achieving... Figure 1 The semiconductor device shown.

[0062] The second material 102 can also be a material that, after being processed by the first process, will be transformed into a fourth material 104. The fourth material 104 and the third material 103 have different etching selectivity ratios. Therefore, by wet etching and controlling the process parameters of wet etching, the fourth material 104 can be selectively etched away while the third material 103 on the sidewalls is retained, resulting in... Figure 1 The semiconductor device shown.

[0063] If manufacturing is required Figure 2 The semiconductor device shown is then:

[0064] The second material 102 can be a material that does not change after being processed by the first process. Thus, after the first process is completed, the second material 102 remains unchanged, resulting in... Figure 2 The semiconductor device shown. The second material 102 is the same as the fourth material 104.

[0065] The second material 102 can also be a material that, after being processed by the first process, will be transformed into the fourth material 104. Thus, after the first process is completed, the second material 102 is transformed into the fourth material 104, resulting in... Figure 2 The semiconductor device shown.

[0066] This application embodiment uses the above-described semiconductor device manufacturing method to manufacture semiconductor devices without the need for a special ET machine. Figure 1 or Figure 2 The semiconductor device shown can also avoid the impact on the third material 103 on the trench sidewalls when the ET machine etches the bottom of the trench. Therefore, using the above semiconductor manufacturing method to manufacture semiconductor devices can result in better quality semiconductor devices.

[0067] It should be noted that, Figure 3 The steps shown above are only the main steps in manufacturing the semiconductor device according to the embodiments of this application, and not all steps. During the manufacturing process of the semiconductor device, additional steps may be required, depending on the product design of the semiconductor device, including grinding, wiring, and manufacturing other corresponding devices.

[0068] Figure 7 This application illustrates a specific process and procedure for implementing the above-described semiconductor device manufacturing method according to another embodiment.

[0069] In this embodiment, the semiconductor device manufacturing method is used to manufacture a BCD device, and the trench in the first material 101 is used to prepare doped electrode pillars. The BCD device requires an oxide thin film to be formed on the sidewall of the trench in which the doped electrode pillars are prepared to isolate the doped electrode pillars, and an opening to be formed under the doped electrode pillars to allow ground wires to be led out from the doped electrode pillars.

[0070] In this embodiment, silicon (Si) is used as the first material 101, titanium nitride (TiN) is used as the second material 102, and silicon dioxide (SiO2) is used as the third material 103. A furnace tube thermal oxidation process is used as the first process to thermally oxidize the first material 101 (silicon) to obtain the third material 103 (silicon oxide).

[0071] Specifically, the manufacturing process for the aforementioned semiconductor devices, such as... Figure 7 As shown, it mainly includes:

[0072] Step S710: A silicon layer is grown using a chemical vapor deposition process to obtain a silicon layer.

[0073] Step S720: Use dry etching process to etch grooves in the silicon layer to obtain deep trenches.

[0074] Step S730: Titanium nitride is grown in the deep trench using physical vapor deposition, such that the thickness difference between the titanium nitride on the trench sidewall and the titanium nitride on the trench bottom is greater than or equal to the thickness difference threshold.

[0075] Physical vapor deposition (PVD) has the following characteristics: as long as the deposition time is long enough and the amount of deposition material is sufficient, the thickness difference between the titanium nitride on the trench sidewall and the titanium nitride on the trench bottom can be large enough.

[0076] Therefore, this embodiment ensures that the thickness difference between titanium nitride on the trench sidewall and titanium nitride on the trench bottom is greater than or equal to the thickness difference threshold by controlling the physical vapor deposition process time and / or the amount of deposited material.

[0077] In this embodiment, the thickness difference between the titanium nitride on the trench sidewall and the titanium nitride at the bottom of the trench is greater than or equal to the thickness difference threshold. This ensures that when the titanium nitride on the trench sidewall is etched later, a portion of the titanium nitride at the bottom of the trench can still be retained. Moreover, the retained portion of the titanium nitride at the bottom of the trench is sufficient to prevent the silicon at the bottom of the trench from being exposed and oxidized into silicon oxide by the thermal oxidation process.

[0078] In step S740, a wet etching process is used to etch away the titanium nitride on the sidewalls of the trench, while retaining the titanium nitride at the bottom of the trench.

[0079] During the wet etching process, the time of the wet etching process can be controlled so that the titanium nitride on the sidewall of the trench is just completely etched away, while retaining as much titanium nitride as possible at the bottom of the trench.

[0080] In step S750, the trench sidewall is thermally oxidized using a furnace tube thermal oxidation process to oxidize the silicon on the trench sidewall into silicon oxide.

[0081] Typically, furnace tube processes are set at temperatures above 400 degrees Celsius. In this embodiment, to ensure that titanium nitride is not oxidized along with the furnace tube process, the temperature of the furnace tube thermal oxidation process is controlled below a preset temperature threshold.

[0082] The preset temperature threshold can be the lowest temperature at which titanium nitride may be oxidized, for example, 700 degrees Celsius, so that the titanium nitride at the bottom of the trench is not oxidized as much as possible.

[0083] The preset temperature threshold can also be a temperature threshold that ensures the silicon at the bottom of the trench is not oxidized. For example, if experiments have shown that at a furnace temperature of around 800 degrees Celsius, even if a small amount of titanium nitride is oxidized, some titanium nitride can still be retained at the bottom of the trench to form a protective film that prevents the silicon at the bottom of the trench from oxidizing, then the preset temperature threshold can also be set to 800 degrees Celsius. If the small amount of titanium oxide generated during thermal oxidation would affect the function or quality of the semiconductor device, the titanium oxide at the bottom of the trench can be etched away using a wet etching process.

[0084] Furthermore, during thermal oxidation, titanium nitride may also react chemically with silicon to form silicon-titanium compounds, such as Ti₂Si in a high-resistivity state or TiSi₂ in a low-resistivity state. These silicon-titanium compounds can also optimize resistance and promote resistivity transitions.

[0085] In step S760, a titanium nitride-doped electrode material is grown in the trench using a physical vapor deposition process to obtain a doped electrode post.

[0086] In this way, the titanium nitride at the bottom of the trench can be fused with the titanium nitride in the doped electrode pillar and become part of the doped electrode pillar, thereby ensuring that an opening is formed at the bottom of the trench under the doped electrode pillar, which can be used to lead out the ground wire.

[0087] Furthermore, this application also provides a semiconductor device, such as... Figure 2 As shown, the semiconductor device includes a trench etched in a first material 101, the sidewalls of the trench being covered with a third material 103, and the bottom of the trench not being covered with the third material 103, forming an opening, or being covered with a fourth material 104.

[0088] The fourth material 104 is different from the third material 103.

[0089] The third material 103 is obtained by processing the first material 101 through the first process, and the fourth material 104 is obtained by processing the second material 102 through the first process. Furthermore, the surface of the third material 103 has no traces of being etched by a special ET machine.

[0090] Compared to semiconductor devices manufactured using existing methods, the third material 103 on the trench sidewalls of the semiconductor device provided in this application is not etched, ensuring greater thickness and quality, resulting in better device quality.

[0091] It should be noted that, in the above embodiments of the semiconductor devices of this application, including the process of manufacturing each embodiment using the semiconductor device manufacturing method of this application, the materials used for each component are not limited, and implementers can flexibly determine them according to implementation conditions and implementation needs.

[0092] Furthermore, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0093] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or components can be combined, or integrated into another device, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, and the indirect coupling or communication connection between devices or units can be electrical, mechanical, or other forms.

[0094] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for manufacturing a semiconductor device, characterized in that, The manufacturing method includes: First growth material (101); Grooves are cut into the first material (101) to obtain grooves; A second material (102) is grown in the trench; The second material (102) on the sidewall of the trench is etched away to expose the first material (101) on the sidewall of the trench, while retaining a portion of the second material (102) at the bottom of the trench; the second material (102) is titanium nitride; The first process is used to process the first material (101) exposed on the sidewall of the trench to transform the first material (101) exposed on the sidewall of the trench into a third material (103); the first process includes a thermal oxidation process; A titanium nitride-doped electrode material is grown in a trench to obtain a doped electrode post. The second material (102) at the bottom of the trench is used to prevent the first material (101) at the bottom of the trench from being converted into the third material (103) by the first process.

2. The manufacturing method according to claim 1, characterized in that, The second material (102) includes any one of the following materials: Materials that do not change after being processed by the first process; After being processed by the first process, the material will be transformed into a fourth material (104), which is the material expected to cover the bottom of the trench.

3. The manufacturing method according to claim 1, characterized in that, The thermal oxidation process includes furnace tube thermal oxidation.

4. The manufacturing method according to claim 1, characterized in that, The temperature of the thermal oxidation process is lower than the minimum temperature at which the second material (102) is thermally oxidized.

5. The manufacturing method according to claim 1, characterized in that, The growth of the second material (102) within the trench includes: A second material (102) was grown in the trench using a physical vapor deposition process.

6. The manufacturing method according to claim 5, characterized in that, In the process of growing the second material (102) within the trench using a physical vapor deposition process, the manufacturing method further includes: Control the physical vapor deposition process time and / or the amount of deposited material so that the thickness difference between the second material (102) grown on the trench sidewall and the second material (102) grown on the trench bottom is greater than or equal to a thickness difference threshold.

7. The manufacturing method according to claim 1, characterized in that, The second material (102) that etches away the sidewalls of the trench includes: The second material (102) on the sidewall of the trench is etched away using a wet etching process.

8. The manufacturing method according to claim 7, characterized in that, In the process of etching away the second material (102) on the trench sidewall using a wet etching process, the manufacturing method further includes: The time of the wet etching process is controlled to ensure that the second material (102) on the sidewall of the trench is etched clean and that a portion of the second material (102) at the bottom of the trench is retained.

9. A semiconductor device, characterized in that, The semiconductor device is manufactured using the manufacturing method described in any one of claims 1-8; the semiconductor device includes trenches etched within a first material (101). The sidewalls of the trench are covered with a third material (103). The bottom of the trench is not covered by a third material (103) to form an opening, or is covered by a fourth material (104); wherein the third material (103) is obtained by transforming the first material (101) after a first process and the surface of the third material (103) has no traces of etching.

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