Method for producing single crystal layer
Through the two-step injection and annealing method, the problems of expensive equipment and poor peeling effect in the preparation of SiC single crystal substrates are solved, and efficient and low-cost single crystal layer manufacturing is achieved, and product quality and production efficiency are improved.
Patent Information
- Application Number
- CN202510429368.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-08
- Publication Date
- 2025-07-18
AI Technical Summary
The traditional SiC single crystal substrate preparation method has problems such as expensive equipment, high energy consumption and long production cycles. In the Smart Cut technology, uneven H+ injection leads to poor peeling effect, affecting the quality of the single crystal layer.
Using two-step implantation and two-step annealing, hydrogen ions H+ and hydrogen molecular ions H2+ are first injected into the SiC substrate, and annealed treatment is carried out at different temperatures to promote the diffusion of hydrogen ions to form micropores and cracks, facilitate peeling, and obtain a high-quality single crystal layer.
It realizes efficient peeling of single crystal layer, reduces production costs and crushing rates, improves the surface quality of single crystal layer, and simplifies the production process.
Smart Images
Figure CN120330889A_ABST
Abstract
Description
Technical Field
[0001] This application relates to semiconductor technology, and particularly to a method for manufacturing a single crystal layer. Background Art
[0002] Silicon carbide (SiC) is a semiconductor material with excellent properties such as a high bandgap, high thermal conductivity, and high breakdown electric field, and is regarded as a representative of the third-generation semiconductor materials. The SiC single crystal substrate is a key material for manufacturing SiC semiconductor devices, and its quality directly affects the performance and reliability of the devices. The traditional method for preparing SiC single crystal substrates is mainly the Physical Vapor Transport (PVT) method, but this method has problems such as expensive equipment, high energy consumption, and long production cycles.
[0003] To solve the problems existing in the traditional method for preparing SiC single crystal substrates, researchers have developed the Smart Cut technology. The Smart Cut technology is an advanced semiconductor material preparation technology, mainly used to achieve the efficient reuse of SiC single crystal substrates. This technology first forms an ion implantation damage layer through H + implantation, and then performs annealing and peeling at high temperature. The implanted H + will form gas or a narrow crack layer / microporous layer in SiC at high temperature, and finally enable the SiC material to be divided into multiple thin slices. After polishing and other treatments, a smooth single crystal SiC thin layer can be obtained, thereby improving the material utilization rate and reducing costs.
[0004] Then, technicians found in practice that a part of the implanted H + will be captured by the broken Si bonds, making the H + ions unable to diffuse sufficiently, resulting in the inability to form bubbles for peeling in some areas, causing the SiC material not to be completely peeled, and resulting in a poor peeling effect. If the dose of implanted H + is increased, it is easy to form high-density defects near the damage layer, which will further hinder the formation of peeling bubbles, thereby affecting the quality of the peeled single crystal layer. Summary of the Invention
[0005] To solve one of the above technical defects, an embodiment of this application provides a method for manufacturing a single crystal layer.
[0006] According to the first aspect of the embodiment of this application, a method for manufacturing a single crystal layer is provided, including:
[0007] Inject hydrogen ions H + into one side of a silicon carbide (SiC) substrate;
[0008] Inject hydrogen molecular ions H2 into the same side of the silicon carbide (SiC) substrate+ ;
[0009] Perform the first annealing treatment on the implanted SiC substrate at the first annealing temperature;
[0010] Perform the second annealing treatment on the implanted SiC substrate at the second annealing temperature, where the second annealing temperature is greater than the first annealing temperature;
[0011] Peel the annealed SiC substrate to obtain a single crystal layer.
[0012] Adopt the two-step implantation and two-step annealing scheme provided by this embodiment. First, implant hydrogen ions H into one side of the silicon carbide SiC substrate + , and then implant hydrogen molecular ions H2 into the same side of the silicon carbide SiC substrate + ; Perform the first annealing treatment on the implanted SiC substrate at the first annealing temperature; Perform the second annealing treatment on the implanted SiC substrate at a higher second annealing temperature, which can activate hydrogen ions H + , promote its rapid diffusion in the SiC substrate to form micropores, and make hydrogen molecular ions H2 + more likely to diffuse into the micropores at high temperature, causing cracks in the SiC substrate and driving the cracks to extend and expand, forming better fracture conditions, which is beneficial for subsequent peeling; then peel the annealed SiC substrate to obtain a single crystal layer. The peeling process is relatively easy, the breakage rate is low, and the surface quality after peeling is high. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:
[0014] Figure 1 is a flowchart of the method for manufacturing a single crystal layer provided by an embodiment of the present application;
[0015] Figure 2 is a schematic diagram of the steps of the method for manufacturing a single crystal layer provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0016] In order to make the technical solutions and advantages in the embodiments of the present application clearer and more understandable, the following further details the exemplary embodiments of the present application with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than an exhaustive list of all embodiments. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.
[0017] This embodiment provides a method for manufacturing a single crystal layer, which can peel off a relatively thin single crystal layer from a silicon carbide (SiC) substrate, and the peeled single crystal layer has high quality.
[0018] As Figure 1 and Figure 2 shown, the method for manufacturing a single crystal layer provided in this embodiment includes:
[0019] Step 101: Inject hydrogen ions (H + .
[0020] The SiC substrate can be a common SiC substrate, or 3C-SiC, 4H-SiC, 6H-SiC, etc. This embodiment only takes 4H-SiC as an example for illustration, and those skilled in the art can directly apply the solution of this embodiment to process other SiC substrates or make adaptive modifications and then apply it to other SiC substrates.
[0021] The SiC substrate has a certain thickness. In this embodiment, a single crystal layer needs to be peeled off from one side of the SiC substrate. For example, if peeling from the upper surface of the SiC substrate in Figure 2 , then when injecting, hydrogen ions (H + ) are injected laterally above the SiC substrate into the SiC substrate.
[0022] The injection energy of hydrogen ions (H + ) can be 100 Kev - 200 Kev, and the injection dose can be 1e16 - 3e16.
[0023] After the injected hydrogen ions (H + ) enter the SiC substrate and are subjected to high-temperature annealing, the diffusion rate is relatively fast, and multiple micropores are quickly formed in the upper region of the SiC substrate. The region where the micropores are formed is called the damaged layer.
[0024] Step 102: Inject hydrogen molecular ions (H2 + ) into the same side of the silicon carbide (SiC) substrate.
[0025] Next, hydrogen molecular ions (H2 + ) are also injected laterally above the SiC substrate. The injection energy of hydrogen molecular ions (H2 + ) is 60 Kev - 300 Kev, and the injection dose is 1e16 - 3e16.
[0026] After the hydrogen ions (H + ) in the above step 101 are subjected to high-temperature annealing, multiple micropores are quickly formed in the implanted damaged layer region of the SiC substrate. This can make the subsequently injected hydrogen molecular ions (H2 + ) diffuse more easily, enabling the hydrogen molecular ions (H2 +Bubbles are formed near the damaged layer to establish good fracture conditions for the subsequent peeling process.
[0027] The above two-step injection process can be completed in one injection device. Place the SiC substrate in the chamber of the injection device, and then sequentially inject hydrogen ions H + and hydrogen molecular ions H2 + into the same side surface of the SiC substrate. The two-step injection process is carried out continuously without moving the SiC substrate, which shortens the production time and also reduces the probability of breakage of the SiC substrate during transportation between different devices.
[0028] Step 103: Perform the first annealing treatment on the injected SiC substrate at the first annealing temperature.
[0029] After the above two-step injection process is completed, send the injected SiC substrate into the annealing device. Start the annealing device and adjust the temperature to the first annealing temperature to perform the first annealing treatment on the SiC substrate. The first annealing temperature can be 400°C - 500°C, such as 450°C, and the annealing time is about 2 hours, which can initially activate hydrogen ions H + and further promote its diffusion in the SiC substrate to form micropores.
[0030] Step 104: Perform the second annealing treatment on the injected SiC substrate at the second annealing temperature, where the second annealing temperature is higher than the first annealing temperature.
[0031] After the first annealing treatment is completed, directly adjust the temperature to the second annealing temperature to perform the second annealing treatment on the SiC substrate. The second annealing temperature is higher than the first annealing temperature, specifically it can be 1000°C - 1300°C, such as 1100°C, and the annealing time is about 0.5 hours. During the second annealing process, the high temperature causes hydrogen ions H + to further diffuse in the SiC substrate to form high-density micropores, and makes hydrogen molecular ions H2 + more likely to diffuse into the micropores at high temperature, and simultaneously generate H2 bubbles, causing cracks in the SiC substrate and driving the cracks to extend, which is beneficial for subsequent peeling.
[0032] The two-step annealing process is carried out continuously in the same device without moving the SiC substrate, which shortens the production time and also reduces the probability of breakage of the SiC substrate during transportation between different devices.
[0033] Step 105: Peel the annealed SiC substrate to obtain a single crystal layer.
[0034] After the previous two-step injection and two-step annealing are completed, place the SiC substrate in the peeling device and peel the upper structure of the SiC substrate to obtain a single crystal layer.
[0035] In the first two steps of implantation and annealing, hydrogen ions H + rapidly diffuse in the SiC substrate to form high-density micropores, and hydrogen molecular ions H2 + are more likely to diffuse into the micropores, causing cracks in the SiC substrate and driving crack propagation and extension, forming good fracture conditions, making peeling easier to achieve, and the surface quality of the peeled single crystal layer is relatively high.
[0036] Adopting the two-step implantation and two-step annealing scheme provided in this embodiment does not require increasing the implantation dose of H. A conventional dose can be used, thereby reducing the probability of forming high-density defects near the damaged layer. At the same time, using a conventional dose can also reduce raw material waste, thereby reducing production costs and improving product quality.
[0037] This embodiment uses two-step annealing, first at a low temperature and then at a high temperature, with the temperature increasing step by step, avoiding the problem of a relatively violent peeling process caused by direct high-temperature annealing; moreover, the two-step annealing process is more sufficient, reducing the damage in the peeling area, thereby improving product quality.
[0038] In the description of this application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to this application.
[0039] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.
[0040] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, and can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0041] While the preferred embodiments of the present application have been described, additional changes and modifications can be made to these embodiments by those skilled in the art once they learn of the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present application.
[0042] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.
Claims
1. A method for manufacturing a single crystal layer, characterized in that, Comprising: Inject hydrogen ions H into one side of the silicon carbide (SiC) substrate + ; Inject hydrogen molecular ions H2 into the same side of the silicon carbide SiC substrate + ; Performing a first annealing treatment on the implanted SiC substrate at a first annealing temperature; Performing a second annealing treatment on the implanted SiC substrate at a second annealing temperature, where the second annealing temperature is greater than the first annealing temperature; Peeling the annealed SiC substrate to obtain a single crystal layer.
2. The manufacturing method of the single crystal layer according to claim 1, wherein, The silicon carbide SiC substrate is a 4H-SiC substrate.
3. The method for manufacturing a single crystal layer according to claim 1 or 2, characterized in that, Hydrogen ion H + The implantation energy is 100 Kev - 200 Kev, and the implantation dose is 1e16 - 3e16.
4. The method for manufacturing a single crystal layer according to claim 1 or 2, characterized in that, Hydrogen molecular ion H2 + The implantation energy is 60 Kev - 300 Kev, and the implantation dose is 1e16 - 3e16.
5. The method for manufacturing a single crystal layer according to claim 1 or 2, characterized in that, The first annealing temperature is 400°C - 500°C.
6. The manufacturing method of the single crystal layer according to claim 5, characterized in that, The first annealing temperature is 450°C.
7. The manufacturing method of the single crystal layer according to claim 5, characterized in that, The duration of the first annealing treatment is 2 hours.
8. The method for manufacturing a single crystal layer according to claim 1 or 2, characterized in that, The second annealing temperature is 1000°C - 1300°C.
9. The method for manufacturing a single crystal layer according to claim 8, wherein, The second annealing temperature is 1100°C.
10. The method for manufacturing a single crystal layer according to claim 1 or 2, characterized in that, The duration of the second annealing treatment is 0.5 hours.