Novel preparation method of semiconductor composite substrate

Abstract

The invention provides a novel preparation method of a semiconductor composite substrate, relates to the technical field of semiconductor chips, and aims to solve the problem of relatively large material loss in a substrate preparation process. The preparation method of the novel semiconductor composite substrate comprises the following steps: providing a supporting layer and a donor layer, wherein the supporting layer comprises a D-level silicon carbide substrate; the donor layer comprises a first surface and a second surface which are oppositely arranged, and the supporting layer is bonded to the first surface of the donor layer; performing laser irradiation on one side, far away from the donor layer, of the supporting layer, forming a modified layer at a position, having a first preset thickness from the first surface, in the donor layer, forming a first sub-layer on a part, from the modified layer to the first surface, of the donor layer, and forming a second sub-layer on a part, from the modified layer to the second surface, of the donor layer; stripping the second sub-layer and the first sub-layer from the modified layer; and polishing the surface, away from the supporting layer, of the first sub-layer to obtain the semiconductor composite substrate. The semiconductor composite substrate is used for preparing electronic equipment.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor chip technology, and in particular to a novel method for preparing a semiconductor composite substrate. Background Art

[0002] High-electron-mobility transistors (HEMTs) are mainly used as power amplifiers in electronic devices. Gallium nitride (GaN)-based HEMTs are widely used in base stations and other equipment due to their high performance. Among them, GaN-based HEMTs are usually made on high-purity silicon carbide substrates through epitaxial growth.

[0003] The formation process of silicon carbide substrate mainly adopts high-purity silicon carbide powder, and obtains SiC crystal by high-temperature sublimation at a temperature of more than 2000 degrees through the physical vapor transport process (PVT). During the growth process of SiC crystal, a high purity growth environment must be maintained (nitrogen in the air needs to be isolated). Then, the SiC crystal is processed by wire cutting, grinding and polishing to obtain silicon carbide substrate.

[0004] However, in the process of obtaining a silicon carbide substrate from a SiC crystal through cutting, grinding and polishing, a large amount of material is lost. Summary of the invention

[0005] The embodiments of the present disclosure provide a novel method for preparing a semiconductor composite substrate, aiming to solve the problem of large material loss during substrate preparation.

[0006] To achieve the above objectives, the embodiments of the present disclosure adopt the following technical solutions: Provided is a novel method for preparing a semiconductor composite substrate, the method comprising: providing a support layer and a donor layer; the support layer comprising: a D-grade silicon carbide substrate, the material of the donor layer being in a single crystal structure; first bonding; the donor layer comprising a first surface and a second surface arranged opposite to each other, and bonding the support layer to the first surface of the donor layer; first laser irradiation; laser irradiation is performed on a side of the support layer away from the donor layer, a modified layer is formed at a position of the donor layer with a first preset thickness away from the first surface, a portion of the donor layer from the modified layer to the first surface forms a first sublayer, and a portion of the donor layer from the modified layer to the second surface forms a second sublayer; first peeling; peeling the second sublayer from the first sublayer from the modified layer; first polishing; polishing the surface of the first sublayer away from the support layer, the first sublayer after polishing forms a single crystal layer, and the single crystal layer and the support layer form a semiconductor composite substrate.

[0007] The above-mentioned embodiment of the present disclosure provides a new method for preparing a semiconductor composite substrate. By bonding a support layer on one side of the donor layer, the support layer has a supporting function, which can improve the machinability of the donor layer, so that the material thickness of the peeled donor layer can be thinner, thereby achieving the purpose of saving materials. In addition, by adopting a method of laser irradiation on the side of the support layer away from the donor layer, there is no limit on the thickness of the processed donor layer, so that the new method for preparing a semiconductor composite substrate can process thicker ingots, so as to avoid the processing method of cutting the ingot first and then preparing the substrate, thereby reducing material loss and reducing costs.

[0008] In some embodiments, a new method for preparing a semiconductor composite substrate further includes: cyclically performing the steps of first bonding, first laser irradiation, first peeling and first polishing, and obtaining a semiconductor composite substrate in each cycle; the cycle is a first cycle, and in the bonding step of each first cycle, the second sublayer in the previous cycle process is used as the donor layer of the current cycle process to bond with the support layer of the current cycle.

[0009] In some embodiments, when the thickness range of the donor layer is <200 μm, the following steps are performed: providing a first supporting layer and a second supporting layer, bonding the first supporting layer to the first surface of the donor layer, and bonding the second supporting layer to the second surface of the donor layer; performing laser irradiation on the side of the first supporting layer away from the donor layer to form a modified layer between the first surface and the second surface of the donor layer; the portion of the donor layer from the modified layer to the first surface forms a first sublayer, and the portion of the donor layer from the modified layer to the second surface forms a second sublayer, and the thickness of the first sublayer and the second sublayer are both greater than or equal to a first preset thickness; peeling the first sublayer and the second sublayer from the modified layer; polishing the surface of the first sublayer away from the first supporting layer to obtain another semiconductor composite substrate.

[0010] In some embodiments, a new method for preparing a semiconductor composite substrate also includes: providing a third supporting layer; second bonding; bonding the third supporting layer to a side of the second sublayer away from the second supporting layer, wherein the second sublayer is a donor layer for forming the next semiconductor composite substrate; second laser irradiation; performing laser irradiation on a side of the third supporting layer away from the donor layer to form a modified layer between the first surface and the second surface of the donor layer; the portion of the donor layer from the modified layer to the first surface forms a first sublayer, and the portion of the donor layer from the modified layer to the second surface forms a second sublayer; second peeling; peeling the first sublayer and the second sublayer from the modified layer; second polishing; polishing the surface of the first sublayer away from the third supporting layer to obtain another semiconductor composite substrate.

[0011] In some embodiments, a new method for preparing a semiconductor composite substrate further includes: cyclically performing the steps of providing a third support layer, second bonding, second laser irradiation, second peeling, and second polishing, and obtaining a semiconductor composite substrate in each cycle; the cycle is a second cycle, and in the bonding step of each second cycle, the second sublayer bonded with the second support layer in the previous cycle is used as the donor layer of the current cycle, and the first surface of the donor layer is bonded to the third support layer of the current cycle.

[0012] In some embodiments, when the thickness of the donor layer bonded with the second support layer is less than 50 μm, the following steps are performed: polishing the surface of the donor layer away from the second support layer to obtain another semiconductor composite substrate.

[0013] In some embodiments, the first preset thickness ranges from 10 μm to 1000 μm.

[0014] In some embodiments, the thickness of the single crystal layer is in a range of 5 μm to 15 μm.

[0015] In some embodiments, the surface roughness of the single crystal layer is Ra≤0.2.

[0016] In some embodiments, the conditions of laser irradiation include at least one of the following: a wavelength range of 532nm to 1064nm, a pulse width range of 500fs to 80ps, an output power range of 1.5W to 12W, a scanning interval range of 0.3mm to 0.5mm, a scanning speed range of 50mm / s to 1200mm / s and a vibration frequency range of 60KHz to 120KHz.

[0017] In some embodiments, bonding includes bonding the support layer to the first surface of the donor layer using a thermal bonding process.

[0018] In some embodiments, the peeling includes peeling the second sub-layer and the first sub-layer from the modified layer using ultrasonic treatment.

[0019] In some embodiments, the ultrasonic power of the ultrasonic treatment ranges from 200W to 1000W.

[0020] In some embodiments, the initial thickness of the donor layer ranges from less than or equal to 30 mm.

[0021] In some embodiments, the surface roughness of the donor layer is Ra≤0.5.

[0022] In some embodiments, the thickness of the support layer ranges from 200 μm to 1000 μm.

[0023] In some embodiments, the surface roughness of the support layer is Ra≤0.5.

[0024] In some embodiments, the material of the donor layer includes any one of silicon carbide, diamond, and gallium oxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the present disclosure, the following briefly introduces the drawings required for use in some embodiments of the present disclosure. Obviously, the drawings described below are only drawings of some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can also be obtained based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams, and are not limitations on the actual size of the products involved in the embodiments of the present disclosure, the actual process of the method, etc.

[0026] Figure 1 is a flow chart of a method for preparing a new semiconductor composite substrate according to some embodiments; Figure 2 It is a structural schematic diagram corresponding to each step of a method for preparing a new semiconductor composite substrate according to some embodiments; Figure 3 is another flow chart of a method for preparing a novel semiconductor composite substrate according to some embodiments; Figure 4 is a schematic structural diagram of a semiconductor composite substrate according to some embodiments; Figure 5 is a schematic diagram of the structure of an electronic device according to some embodiments. DETAILED DESCRIPTION

[0027] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present disclosure.

[0028] In the description of the present disclosure, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply 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 understood as a limitation on the present disclosure.

[0029] Unless the context requires otherwise, throughout the specification and claims, the term "including" is to be interpreted as an open, inclusive meaning, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "exemplarily" or "some examples" and the like are intended to indicate that specific features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present disclosure. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0030] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, unless otherwise specified, "plurality" means two or more.

[0031] When describing some embodiments, the expression "connected" and its derivatives may be used. For example, when describing some embodiments, the term "connected" may be used to indicate that two or more components have direct physical or electrical contact with each other.

[0032] “At least one of A, B, and C” has the same meaning as “at least one of A, B, or C” and both include the following combinations of A, B, and C: A only, B only, C only, the combination of A and B, the combination of A and C, the combination of B and C, and the combination of A, B, and C.

[0033] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.

[0034] As used herein, "about," "substantially," or "approximately" includes the stated value and an average value that is within an acceptable range of variation from the particular value as determined by one of ordinary skill in the art taking into account the measurements in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).

[0035] Exemplary embodiments are described herein with reference to cross-sectional views and / or plan views that are idealized exemplary drawings. In the drawings, the thickness of layers and regions are exaggerated for clarity. Therefore, variations in shape relative to the drawings due to, for example, manufacturing techniques and / or tolerances are conceivable. Therefore, the exemplary embodiments should not be interpreted as being limited to the shapes of the regions shown herein, but include shape deviations due to, for example, manufacturing. For example, an etched region shown as a rectangle will typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shape of regions of the device, and are not intended to limit the scope of the exemplary embodiments.

[0036] As used herein, the term "substrate" refers to a material onto which subsequent layers of material may be added. The substrate itself may be patterned. The material added onto the substrate may be patterned or may remain unpatterned.

[0037] As a representative substrate material for third-generation semiconductors, SiC substrate has a Mohs hardness of >9.2, second only to diamond. Therefore, the traditional cutting method of SiC substrates is a multi-wire cutting process: the consumables are metal wires and oily diamond suspensions. Taking the cutting of a 6-inch substrate as an example, a single cutting time is about 130 hours, and the diameter of the wire saw used in the cutting process is 0.16mm. In addition, due to the particle size of the abrasive in the mortar and the vibration of the cutting wire mesh, each cutting loss is about 180μm / piece; in addition, mechanical fractures during the cutting process cause cutting damage, and the depth of the damage layer is about 55μm / face to 60μm / face, and the total loss of the two surfaces of a single piece is 110μm / piece to 120μm / piece. Using multi-wire cutting and subsequent grinding and polishing processes, the total material loss per piece is about 300μm / piece. Taking the target thickness of the 6-inch substrate obtained as 350μm as an example, the material loss of a single piece reaches more than 40%.

[0038] From the above, it can be seen that how to reduce the material loss in the SiC substrate cutting process or produce more substrate slices with the same thickness of crystal while ensuring the substrate quality is the key issue in substrate processing at present.

[0039] Based on this, the embodiments of the present disclosure provide a new method for preparing a semiconductor composite substrate, such as Figure 1 As shown, a novel method for preparing a semiconductor composite substrate includes steps: R1 to R6.

[0040] R1, such as Figure 2 As shown, a support layer 11 and a donor layer 120 are provided; the support layer 11 includes: a D-level silicon carbide substrate, and the material of the donor layer 120 is a single crystal structure.

[0041] Exemplarily, the initial thickness d1 of the donor layer 120 is less than or equal to 30 mm. That is, the ingot can be directly used to prepare the semiconductor composite substrate 10, without cutting the ingot into a crystal structure of, for example, 200 μm to 500 μm before processing the substrate or the semiconductor composite substrate 10, which can effectively avoid the loss of material when cutting the ingot into a crystal structure with a thickness range of, for example, 200 μm to 500 μm, thereby reducing costs.

[0042] Exemplarily, the material of the donor layer 120 includes any one of silicon carbide, diamond and gallium oxide.

[0043] Exemplarily, the thickness h2 of the support layer 11 ranges from 200 μm to 1000 μm. For example, the thickness h2 of the support layer 11 is 200 μm, 300 μm, 500 μm, 600 μm, 700 μm, 800 μm or 1000 μm, etc., which is not limited here.

[0044] It should be noted that the material of the donor layer 120 is, for example, P-grade silicon carbide, and the difference between P-grade silicon carbide and D-grade silicon carbide lies in the silicon carbide content. The silicon carbide content of P-grade silicon carbide is higher than that of D-grade silicon carbide.

[0045] Exemplarily, before providing the donor layer 120 , a step of polishing and cleaning the end surface of the donor layer 120 is also included.

[0046] R2, such as Figure 2 As shown, the first bonding; the donor layer 120 includes a first surface m1 and a second surface m2 arranged opposite to each other, and the support layer 11 is bonded to the first surface m1 of the donor layer 120.

[0047] It should be noted that the two opposite surfaces of the donor layer 120 along the direction of the thickness d1 are the first surface m1 and the second surface m2, respectively. Taking the material of the donor layer 120 as silicon carbide as an example, the first surface m1 is the C surface of the donor layer 120, and the second surface m2 is the Si surface of the donor layer 120. The C surface refers to the (000-1) surface of silicon carbide, and the terminating atoms of this surface are carbon atoms. The Si surface refers to the (0001) crystal plane of the silicon carbide wafer, and the terminating atoms of this surface are silicon atoms. The difference between the C surface and the Si surface will affect the physical and chemical properties of the SiC wafer, such as thermal conductivity, electrical conductivity, carrier mobility and interface surface density. The selection of the C surface and the Si surface will also affect the manufacturing process and performance of SiC devices, such as epitaxial growth, ion implantation, oxidation, metal deposition and contact resistance.

[0048] The support layer 11 is bonded to the first surface m1 of the donor layer 120, that is, the support layer 11 is bonded to the C-surface of the donor layer 120. Moreover, for the two surfaces of silicon carbide that are opposite to each other along the direction where the thickness d1 is located, when the first surface m1 is one of the C-surface and the Si-surface, then the second surface m2 is the other of the C-surface and the Si-surface, that is, when the support layer 11 is bonded to the C-surface of the donor layer 120, after the subsequent peeling and polishing process is performed on the side of the donor layer 120 that is away from the support layer 11, the surface of the side of the donor layer 120 that is away from the support layer 11 is still the Si-surface.

[0049] Exemplarily, the support layer 11 is bonded to the first surface m1 of the donor layer 120 using a thermal bonding process.

[0050] Exemplarily, the surface roughness of the donor layer 120 is Ra≤0.5, and the surface roughness of the support layer 11 is Ra≤0.5. Wherein, Ra represents the arithmetic mean deviation of the profile. By setting the surface roughness of the donor layer 120 to Ra≤0.5 and the surface roughness of the support layer 11 to Ra≤0.5, it can be ensured that there are no bubbles and particles at the bonding interface between the donor layer 120 and the support layer 11, and the bonding effect between the donor layer 120 and the support layer 11 is improved, while ensuring that the laser irradiation light in the subsequent steps passes through the bonding interface between the donor layer 120 and the support layer 11, thereby improving the modification effect on the donor layer 120 and facilitating the operation of the subsequent stripping step.

[0051] R3, such as Figure 2 As shown, a first laser irradiation is performed; laser irradiation is performed on a side of the support layer 11 away from the donor layer 120, a modified layer 12a is formed at a position in the donor layer 120 with a first preset thickness d11 away from the first surface m1, a portion of the donor layer 120 from the modified layer 12a to the first surface m1 forms a first sublayer 121, and a portion of the donor layer 120 from the modified layer 12a to the second surface m2 forms a second sublayer 122.

[0052] It should be noted that when the material of the donor layer 120 includes silicon carbide, the modified layer 12 a is decomposed from single crystal SiC into amorphous Si, C and SiC.

[0053] Since the material of the support layer 11 is a D-grade silicon carbide substrate, the light irradiated by the laser can pass through the D-grade silicon carbide substrate.

[0054] Exemplarily, the conditions of laser irradiation include at least one of the following: a wavelength range of 532nm to 1064nm, a pulse width range of 500fs to 80ps, an output power range of 1.5W to 12W, a scanning interval range of 0.3mm to 0.5mm, a scanning speed range of 50mm / s to 1200mm / s and a vibration frequency range of 60KHz to 120KHz.

[0055] For example, the wavelength is 532nm, 650nm, 710nm, 790nm, 870nm, 960nm, 1032nm or 1064nm, the pulse width is 500fs, 600fs, 650fs, 750fs, 800fs, 1ps, 10ps, 20ps, 30ps, 40ps, 50ps, 60ps, 70ps or 80ps, the output power is 1.5W, 3W, 4W, 6W, 7W, 9W, 10 W, 11W or 12W, etc., the scanning interval is 0.3mm, 0.4mm or 0.5mm, etc., the scanning speed is 50mm / s, 100mm / s, 200mm / s, 400mm / s, 550mm / s, 600mm / s, 750mm / s, 800mm / s or 1200mm / s, etc., the vibration frequency is 60KHz, 75KHz, 80KHz, 90KHz, 100KHz or 120KHz, etc., and there is no limitation here.

[0056] Theoretically, the smaller the laser scanning interval, the more interconnected cracks will be that extend from the focal point to the surrounding area, forming a more fragile amorphous modified area, which will reduce the tensile stress required for subsequent ultrasonic-assisted peeling, and the surface roughness and surface shape will be relatively good after peeling. However, this affects the efficiency of laser modification, so the embodiments of the present disclosure provide a reasonable laser modification scanning interval, laser energy, and scanning speed to improve the efficiency of laser modification while ensuring the quality of the material of the donor layer 120 after peeling.

[0057] Exemplarily, the first preset thickness d11 ranges from 10 μm to 1000 μm.

[0058] For example, the first preset thickness d11 is 10 μm, 20 μm, 50 μm, 100 μm, 125 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 450 μm, 600 μm or 1000 μm, etc., which is not limited here.

[0059] By varying the laser irradiation conditions, the modified layer 12 a may be formed at a position of the donor layer 120 at a different first preset thickness d11 from the first surface m1 .

[0060] For example, the wavelength of laser irradiation is 1030 nm, the pulse width is 800 fs, the output power is 3.5 W, the scanning interval is 0.5 mm, the scanning speed is 800 mm / s, and the vibration frequency is 80 KHz. At this time, the first preset thickness d11 is about 50 μm. In other words, the 50 μm thick portion of the donor layer 120 can be used to form a semiconductor composite substrate 10.

[0061] For another example, the wavelength of laser irradiation is 1030nm, the pulse width is 800fs, the output power is 2.5w, the scanning interval is 0.3mm, the scanning speed is 600mm / s, and the laser vibration frequency is 100KHz. At this time, the first preset thickness d11 is about 40μm. In other words, the 40μm thick portion of the donor layer 120 can be used to form a semiconductor composite substrate 10.

[0062] Furthermore, after parameter optimization, the sub-damage layer around the laser stripping modified layer 12a is reduced, and the material to be removed by grinding and polishing can be reduced to 30μm, that is, the loss of a single piece of material to form a semiconductor composite substrate 10 is about 60μm. In this way, a donor layer 120 can obtain more semiconductor composite substrates 10 to reduce costs.

[0063] R4, such as Figure 2 As shown, in the first peeling, the second sub-layer 122 and the first sub-layer 121 are peeled off from the modified layer 12a.

[0064] Exemplarily, ultrasonic treatment is used to peel off the second sub-layer 122 and the first sub-layer 121 from the modified layer 12a.

[0065] Exemplarily, the ultrasonic power of the ultrasonic treatment ranges from 200W to 1000W. For example, the ultrasonic power of the ultrasonic treatment is 200W, 350W, 400W, 500W, 700W, 800W, 850W, 900W or 1000W, etc., which is not limited here.

[0066] It should be noted that the principle of ultrasonic assisted peeling is to apply ultrasonic waves at a frequency close to or slightly larger than the natural frequency of the single crystal material of the donor layer 120. When ultrasonic waves are applied, a resonance-like effect can be generated inside the material to generate tensile stress and separate at the position of the modified layer 12a.

[0067] R5, such as Figure 2 As shown, the first polishing is to polish the surface of the first sublayer 121 away from the support layer 11, and the polished first sublayer 121 forms a single crystal layer 12, and the single crystal layer 12 and the support layer 11 form a semiconductor composite substrate 10.

[0068] For the introduction of the semiconductor composite substrate 10 , please refer to the subsequent contents and will not be described in detail here.

[0069] R6, such as Figure 2 As shown, the steps of first bonding, first laser irradiation, first peeling and first polishing are performed cyclically, and a semiconductor composite substrate 10 is obtained in each cycle; this cycle is the first cycle, and in the bonding step of each first cycle, the second sublayer 122 in the previous cycle process is used as the donor layer 120 of the current cycle process to bond with the support layer 11 of the current cycle.

[0070] It should be noted that, in the polishing step R5, the surface of the second sub-layer 122 separated from the first sub-layer 121 is also polished to remove the sub-damage layer formed in the second sub-layer 122 due to the modification, and the second sub-layer 122 with the sub-damage layer removed is used as the donor layer 120 of the next cycle and bonded to the support layer 11 of the next cycle.

[0071] Through the above steps R1 to R6, the donor layer 120 is used to prepare multiple semiconductor composite substrates 10 through a cyclic method, making full use of the donor layer 120 to achieve the purpose of saving materials. Moreover, due to the setting of the laser irradiation conditions, the first preset thickness d11 can be flexibly controlled so that the donor layer 120 for preparing a single semiconductor composite substrate 10 consumes less material. For example, the thickness of the donor layer 120 formed into a single semiconductor composite substrate 10 is 40μm, 30μm or less than 30μm. Compared with the single-chip loss of about 300μm in the related art, the embodiment of the present disclosure further saves materials.

[0072] Furthermore, by laser irradiating the side of the support layer 11 away from the donor layer 120, the thickness d1 of the donor layer 120 can be processed to 30 mm. That is, the ingot can be directly used to prepare the semiconductor composite substrate 10, without cutting the ingot into a crystal structure with a thickness range of, for example, 200 μm to 500 μm before processing the substrate or the semiconductor composite substrate 10, which can effectively avoid the loss of materials when cutting the ingot into a crystal structure with a thickness of 200 μm to 500 μm, thereby reducing costs.

[0073] In some embodiments, Figure 3 As shown, when the thickness d1 of the donor layer 120 is in the range of <200 μm, that is, when the second sublayer 122 serves as the donor layer 120 of the next cycle, at this time, the thickness d1 of the donor layer 120 is <200 μm, the following steps are performed: R7 to R16.

[0074] R7, such as Figure 2 As shown, a first supporting layer 111 and a second supporting layer 112 are provided, the first supporting layer 111 is bonded to a first surface m1 of a donor layer 120 , and the second supporting layer 112 is bonded to a second surface m2 of the donor layer 120 .

[0075] R8, such as Figure 2As shown, laser irradiation is performed on the side of the first supporting layer 111 away from the donor layer 120, and a modified layer 12a is formed between the first surface m1 and the second surface m2 of the donor layer 120; the portion of the donor layer 120 from the modified layer 12a to the first surface m1 forms a first sublayer 121, and the portion of the donor layer 120 from the modified layer 12a to the second surface m2 forms a second sublayer 122, and the thickness of the first sublayer 121 and the second sublayer 122 are both greater than or equal to the first preset thickness d11.

[0076] R9, such as Figure 2 As shown, the first sub-layer 121 and the second sub-layer 122 are peeled off from the modified layer 12a.

[0077] For the introduction of peeling, please refer to step R4 and will not be repeated here.

[0078] R10, such as Figure 2 As shown, the surface of the first sub-layer 121 away from the first supporting layer 111 is polished to obtain another semiconductor composite substrate 10 .

[0079] R11, such as Figure 2 As shown, a third supporting layer 113 is provided.

[0080] R12, such as Figure 2 As shown, the second bonding is to bond the third supporting layer 113 to a side of the second sub-layer 122 away from the second supporting layer 112 , where the second sub-layer 122 is a donor layer 120 for forming the next semiconductor composite substrate 10 .

[0081] R13, such as Figure 2 As shown, a second laser irradiation is performed; laser irradiation is performed on the side of the third supporting layer 113 away from the donor layer 120 to form a modified layer 12a between the first surface m1 and the second surface m2 of the donor layer 120; the portion of the donor layer 120 from the modified layer 12a to the first surface m1 forms a first sublayer 121, and the portion of the donor layer 120 from the modified layer 12a to the second surface m2 forms a second sublayer 122.

[0082] R14, such as Figure 2 As shown, the second peeling is to peel off the first sub-layer 121 and the second sub-layer 122 from the modified layer 12a.

[0083] R15, such as Figure 2 As shown, the second polishing is to polish the surface of the first sub-layer 121 away from the third supporting layer 113 to obtain another semiconductor composite substrate 10.

[0084] R16, such as Figure 2As shown, the steps of providing a third supporting layer, second bonding, second laser irradiation, second stripping and second polishing are performed cyclically, and a semiconductor composite substrate 10 is obtained in each cycle; this cycle is a second cycle, and in the bonding step of each second cycle, the second sublayer 122 bonded with the second supporting layer 112 in the previous cycle is used as the donor layer 120 of the current cycle, and the first surface m1 of the donor layer 120 is bonded to the third supporting layer 113 of the current cycle.

[0085] Through steps R7 to R16, a donor layer 120 with a thickness range of <200 μm is formed into multiple semiconductor composite substrates 10, and two support layers 11, namely the first support layer 111 and the second support layer 112, or the third support layer 113 and the second support layer 112 are respectively bonded to the C surface and Si surface of the donor layer 120. The support layer 11 has a supporting effect on the donor layer 120, thereby improving the machinability of the donor layer 120 and facilitating the processing of the thinner donor layer 120.

[0086] Moreover, by adopting the method of laser irradiation on the side of the support layer 11 away from the donor layer 120, the laser irradiation can be performed after the first surface m1 and the second surface m2 of the donor layer 120 are bonded with the support layer 11, so that the donor layer 120 with a thickness range of <200 μm can form more than or equal to three semiconductor composite substrates 10. The purpose is to improve the yield of forming a semiconductor composite substrate 10 with one donor layer 120 and save costs.

[0087] It should be noted that, since the first support layer 111 is bonded to the first surface m1 of the donor layer 120, and the third support 113 is bonded to the first surface m1 of the donor layer 120, the second surface m2 (Si surface) of the semiconductor composite substrate 10 having the first support layer 111 and the second surface m2 (Si surface) of the semiconductor composite substrate 10 having the third support layer 113 can be used to produce an epitaxial layer to form a high electron mobility transistor 13 (such as Figure 5 as shown).

[0088] In some examples, such as Figure 2 and Figure 3 As shown, when the thickness d1 of the donor layer 120 bonded with the second support layer 112 is in the range of <50 μm, the following steps are performed: R17, polishing the surface of the donor layer 120 away from the second support layer 112 to obtain another semiconductor composite substrate 10.

[0089] It should be noted that, since the second support layer 112 is bonded to the second surface m2 of the donor layer 120 , the first surface m1 (C-plane) of the semiconductor composite substrate 10 having the second support layer 112 can be used as a seed crystal in a physical vapor transport method for growing SiC single crystals.

[0090] like Figure 4 As shown, an embodiment of the present disclosure further provides a semiconductor composite substrate 10, the semiconductor composite substrate 10 includes: a support layer 11 and a single crystal layer 12, the support layer 11 includes: a D-grade silicon carbide substrate; the single crystal layer 12 is bonded to one side of the support layer 11, and the thickness h1 of the single crystal layer 12 ranges from 5μm to 15μm.

[0091] From the above content about a new method for preparing a semiconductor composite substrate, it can be seen that the setting of bonding the support layer 11 to one side of the donor layer 120, combined with the laser irradiation process, can obtain a semiconductor composite substrate 10 with a thinner single crystal layer 12 thickness h1, thereby reducing material loss and manufacturing cost.

[0092] Exemplarily, the thickness h1 of the single crystal layer 12 is 5 μm, 6 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm or 15 μm, etc., which is not limited here.

[0093] Exemplarily, the material of the single crystal layer 12 includes any one of silicon carbide, diamond and gallium oxide.

[0094] The above-mentioned novel method for preparing a semiconductor composite substrate can be used to prepare a single crystal layer 12 having any one of silicon carbide, diamond and gallium oxide.

[0095] In some examples, such as Figure 4 As shown, the surface roughness of the single crystal layer 12 is in the range of Ra≤0.2 nm.

[0096] By setting the surface roughness of the single crystal layer 12 to be in the range of Ra≤0.2 nm, the single crystal layer 12 can be used for epitaxial growth of semiconductor devices, for example, the semiconductor device includes a high electron mobility transistor 13 (such as Figure 5 as shown).

[0097] In some examples, such as Figure 4 As shown, the thickness h2 of the support layer 11 ranges from 200 μm to 1000 μm.

[0098] Exemplarily, the thickness h2 of the support layer 11 is 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 600 μm, 700 μm, 750 μm, 800 μm, 900 μm or 1000 μm, etc., which is not limited here.

[0099] By setting the thickness h2 of the support layer 11 to a range of 200μm to 1000μm, it can be ensured that the support layer 11 has a good supporting effect on the donor layer 120, so as to obtain a semiconductor composite substrate 10 with a thinner thickness h1 of the single crystal layer 12, thereby increasing the number of semiconductor composite substrates 10 formed by one donor layer 120, improving the yield of the semiconductor composite substrate 10, and saving costs.

[0100] like Figure 5 As shown, an embodiment of the present disclosure further provides an electronic device 100 , which includes the semiconductor composite substrate 10 as described in any of the above embodiments, and further includes: a high electron mobility transistor 13 , which is located on one side of the semiconductor composite substrate 10 .

[0101] Exemplarily, the electronic device 100 is a user device or terminal device of different types such as a computer, a mobile phone, a tablet computer, a wearable device, and a vehicle-mounted device; the electronic device 100 may also be a network device such as a base station. The specific form of the electronic device 100 is not particularly limited in the embodiment of the present application.

[0102] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A new method for preparing a semiconductor composite substrate, characterized in that: include: Providing a support layer and a donor layer; the support layer comprises: a D-grade silicon carbide substrate, and the material of the donor layer is in a single crystal structure; First bonding; the donor layer comprises a first surface and a second surface arranged opposite to each other, and the support layer is bonded to the first surface of the donor layer; first laser irradiation; performing laser irradiation on a side of the support layer away from the donor layer, forming a modified layer at a position of the donor layer with a first preset thickness away from the first surface, a portion of the donor layer from the modified layer to the first surface forming a first sublayer, and a portion of the donor layer from the modified layer to the second surface forming a second sublayer; First peeling: peeling the second sub-layer and the first sub-layer from the modified layer; First polishing: polishing the surface of the first sub-layer away from the support layer, so that the first sub-layer after polishing forms a single crystal layer, and the single crystal layer and the support layer form a semiconductor composite substrate.

2. A method for preparing a new semiconductor composite substrate according to claim 1, characterized in that: Also includes: cyclically performing the steps of the first bonding, the first laser irradiation, the first stripping and the first polishing, and obtaining the semiconductor composite substrate in each cycle; This cycle is the first cycle. In each bonding step of the first cycle, the second sub-layer in the previous cycle is used as the donor layer in the current cycle to bond with the support layer in the current cycle.

3. A method for preparing a new semiconductor composite substrate according to claim 2, characterized in that: When the thickness of the donor layer is in the range of <200 μm, the following steps are performed: Providing a first supporting layer and a second supporting layer, bonding the first supporting layer to the first surface of the donor layer, and bonding the second supporting layer to the second surface of the donor layer; Performing laser irradiation on a side of the first supporting layer away from the donor layer to form a modified layer between the first surface and the second surface of the donor layer; the portion of the donor layer from the modified layer to the first surface forms a first sublayer, and the portion of the donor layer from the modified layer to the second surface forms a second sublayer, and the thickness of the first sublayer and the second sublayer are both greater than or equal to the first preset thickness; peeling the first sub-layer and the second sub-layer from the modified layer; The surface of the first sub-layer away from the first supporting layer is polished to obtain another semiconductor composite substrate.

4. A method for preparing a new semiconductor composite substrate according to claim 3, characterized in that: Also includes: providing a third support layer; Second bond; bonding the third supporting layer to a side of the second sublayer away from the second supporting layer, the second sublayer being a donor layer for forming a next semiconductor composite substrate; second laser irradiation; performing laser irradiation on a side of the third supporting layer away from the donor layer to form a modified layer between the first surface and the second surface of the donor layer; the portion of the donor layer from the modified layer to the first surface forms a first sublayer, and the portion of the donor layer from the modified layer to the second surface forms a second sublayer; Second peeling: peeling the first sub-layer and the second sub-layer from the modified layer; Second polishing; The surface of the first sub-layer away from the third supporting layer is polished to obtain another semiconductor composite substrate.

5. A method for preparing a new semiconductor composite substrate according to claim 4, characterized in that: Also includes: cyclically performing the steps of providing a third supporting layer, the second bonding, the second laser irradiation, the second stripping and the second polishing, and obtaining a semiconductor composite substrate in each cycle; This cycle is the second cycle. In each bonding step of the second cycle, the second sublayer bonded with the second supporting layer in the previous cycle is used as the donor layer of the current cycle, and the first surface of the donor layer is bonded to the third supporting layer of the current cycle.

6. A method for preparing a new semiconductor composite substrate according to claim 5, characterized in that: When the thickness of the donor layer bonded with the second support layer is in the range of <50 μm, the following steps are performed: The surface of the donor layer away from the second supporting layer is polished to obtain another semiconductor composite substrate.

7. The method for preparing a new semiconductor composite substrate according to claim 1, characterized in that: The first preset thickness ranges from 10 μm to 1000 μm.

8. The method for preparing a new semiconductor composite substrate according to claim 1, characterized in that: The thickness of the single crystal layer is in the range of 5 μm to 15 μm.

9. The method for preparing a new semiconductor composite substrate according to claim 1, characterized in that: The surface roughness of the single crystal layer is Ra≤0.

2.

10. The method for preparing a new semiconductor composite substrate according to claim 1, characterized in that: The conditions of the laser irradiation include at least one of the following: a wavelength range of 532nm to 1064nm, a pulse width range of 500fs to 80ps, an output power range of 1.5W to 12W, a scanning interval range of 0.3mm to 0.5mm, a scanning speed range of 50mm / s to 1200mm / s and a vibration frequency range of 60KHz to 120KHz.

11. The method for preparing a new semiconductor composite substrate according to claim 1, characterized in that: The bonding includes: bonding the support layer to the first surface of the donor layer using a thermal bonding process.

12. The method for preparing a new semiconductor composite substrate according to claim 1, characterized in that: The peeling includes: peeling the second sub-layer and the first sub-layer from the modified layer by ultrasonic treatment.

13. A method for preparing a new semiconductor composite substrate according to claim 12, characterized in that: The ultrasonic power of the ultrasonic treatment ranges from 200W to 1000W.

14. The method for preparing a new semiconductor composite substrate according to claim 1, characterized in that: The initial thickness of the donor layer ranges from less than or equal to 30 mm.

15. The method for preparing a new semiconductor composite substrate according to claim 1, characterized in that: The surface roughness of the donor layer is Ra≤0.

5.

16. The method for preparing a new semiconductor composite substrate according to claim 1, characterized in that: The thickness of the support layer ranges from 200 μm to 1000 μm.

17. The method for preparing a new semiconductor composite substrate according to claim 1, characterized in that: The surface roughness of the support layer is Ra≤0.

5.

18. A method for preparing a new semiconductor composite substrate according to any one of claims 1 to 17, characterized in that: The material of the donor layer includes any one of silicon carbide, diamond and gallium oxide.

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