Bonding device and composite substrate preparation method

Abstract

The embodiment of the invention provides a bonding device and a composite substrate preparation method, relates to the technical field of semiconductors, and is used for improving the bonding quality of two warped substrates. The bonding device comprises a first pressure plate, a second pressure plate and a control device, wherein the first pressure plate and the second pressure plate are oppositely arranged; the first pressure plate and / or the second pressure plate comprises a plurality of sub pressure plates which are separately arranged; the control equipment is connected with the first pressure plate and the second pressure plate; the control device is configured to be capable of controlling the pressure applied by each sub-platen. Different bonding pressures are applied to the bonding area in a partitioned manner through the first pressure plate and the second pressure plate, so that the bonding pressures are adaptive to different warping conditions of the substrate to be bonded, and the bonding quality is improved. The bonding device and the preparation method of the composite substrate are used for preparing the high-quality composite substrate.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a bonding device and a method for preparing a composite substrate. Background Technology

[0002] As a third-generation semiconductor material, silicon carbide (SiC) has excellent properties such as wide bandgap, high physical hardness, high thermal conductivity, and high chemical stability. It can be used to fabricate devices that are resistant to high temperature, high pressure, high frequency, and high power, and is therefore widely used in fields such as 5G communication, aerospace, and new energy vehicles.

[0003] However, SiC single-crystal substrates are very expensive. In practical applications, composite substrates are often used, where a thin layer of high-quality single-crystal SiC is bonded onto a lower-quality, cheaper substrate to reduce costs. Because the substrate may have some warping, the bonding yield is low, the bonding area is small, and the bonding quality is poor, resulting in a composite substrate surface that does not meet actual processing requirements. Therefore, how to prepare high-quality composite substrates has become an urgent technical problem to be solved. Summary of the Invention

[0004] This disclosure provides a bonding device and a method for preparing a composite substrate, which are used to prepare a high-quality composite substrate.

[0005] To achieve the above objectives, the present disclosure provides the following technical solutions: In one aspect of this disclosure, a bonding apparatus is provided, comprising: a first pressure plate and a second pressure plate disposed opposite to each other, the first pressure plate and / or the second pressure plate comprising a plurality of separately disposed sub-pressure plates; a control device connected to the first pressure plate and the second pressure plate; the control device being configured to control the pressure applied by each of the sub-pressure plates.

[0006] In some embodiments, the plurality of sub-pressure plates include a central sub-pressure plate and peripheral sub-pressure plates, the peripheral sub-pressure plates surrounding the central sub-pressure plate.

[0007] In some embodiments, both the first pressure plate and the second pressure plate include a plurality of separately arranged sub-pressure plates; along the bonding pressure direction, the projection of the sub-pressure plates of the first pressure plate coincides with the projection of the sub-pressure plates of the second pressure plate.

[0008] In some embodiments, both the first pressure plate and the second pressure plate include a plurality of separately arranged sub-pressure plates; wherein, the gap between the plurality of sub-pressure plates of the first pressure plate is a first gap, and the gap between the plurality of sub-pressure plates of the second sub-pressure plate is a second gap; along the bonding pressure direction, the projections of the first gap and the projections of the second gap are arranged alternately.

[0009] In another aspect of this disclosure, a method for preparing a composite substrate is provided, comprising: preparing a first substrate, the first substrate including a release layer; obtaining a second substrate; wherein the defect density of the first substrate is less than the defect density of the second substrate, and at least one of the first substrate and / or the second substrate is warped; controlling the bonding pressure of different regions according to the warping direction of the first substrate, bonding the first substrate and the second substrate together to form a third substrate; and peeling off a portion of the first substrate along the release layer to form a composite substrate.

[0010] In some embodiments, the step of controlling the bonding pressure in different regions according to the warp direction of the first substrate to bond the first substrate and the second substrate to form a third substrate includes: performing surface profile detection on the first substrate and the second substrate to obtain the warp directions of the first substrate and the second substrate; bonding the first substrate and the second substrate; when the warp directions of the first substrate and the second substrate are opposite, the bonding pressure on the first substrate and / or the second substrate remains unchanged along the direction from the center to the edge of the first substrate; when the warp directions of the first substrate and the second substrate are the same, and the warp direction of the first substrate is towards the second substrate, the bonding pressure on the first substrate and / or the third substrate remains unchanged along the direction from the center to the edge of the first substrate. The bonding pressure on the two substrates decreases sequentially. When the warp directions of the first and second substrates are the same, and the warp direction of the first substrate is away from the second substrate, the bonding pressure on the first substrate and / or the second substrate increases sequentially along the direction from the center of the first substrate to the edge. When the second substrate is not warped, and the warp direction of the first substrate is towards the second wafer, the bonding pressure on the first substrate and / or the second substrate decreases sequentially along the direction from the center of the first substrate to the edge. When the second substrate is not warped, and the warp direction of the first substrate is away from the second wafer, the bonding pressure on the first substrate and / or the second substrate increases sequentially along the direction from the center of the first substrate to the edge.

[0011] In some embodiments, ion implantation is performed on a first side of the first substrate to form a release layer; the release layer is located within the first substrate, and the portion of the first substrate located away from the first side of the release layer is a substrate, and the portion of the first substrate located near the first side of the release layer is a functional layer.

[0012] In some embodiments, the stripping of the first substrate includes: heating the third substrate to a first preset temperature and holding it at that temperature for a first preset time, causing the third substrate to break along the direction of the stripping layer.

[0013] In some embodiments, heating the third substrate to a first preset temperature includes: heating the third substrate to a second preset temperature and holding it at that temperature for a second preset time, thereby enhancing the bonding force between the first substrate and the second substrate; and heating the second preset temperature to the first preset temperature.

[0014] In some embodiments, after peeling off a portion of the first substrate to form a composite substrate, the method further includes: heating the composite substrate to a third preset temperature and holding it at that temperature for a third preset time to improve the quality of the composite substrate; and polishing the functional surface of the composite substrate, wherein the functional surface is the surface exposed after the third substrate peels off a portion of the first substrate.

[0015] In some embodiments, before bonding the first substrate and the second substrate, the method further includes: performing a surface activation treatment on the bonding surfaces of the first substrate and the second substrate. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this disclosure, the accompanying drawings used in some embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are only drawings of some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams and are not intended to limit the actual size of the product, the actual flow of the method, the actual timing of the signals, etc. involved in the embodiments of this disclosure.

[0017] Figure 1 This is a flowchart of a composite substrate fabrication method provided in an embodiment of the present disclosure; Figure 2 A flowchart illustrating the bonding of a first substrate and a second substrate is provided as an embodiment of this disclosure; Figure 3 A bonding pressure flowchart for confirming the bonding of a first substrate and a second substrate is provided as an embodiment of this disclosure; Figure 4 This is a schematic diagram of a bonding scenario provided in an embodiment of the present disclosure; Figure 5 This is a schematic diagram of a second bonding scenario provided in an embodiment of the present disclosure; Figure 6 This is a schematic diagram of a bonding scenario three provided in an embodiment of the present disclosure; Figure 7 This is a schematic diagram of a bonding scenario four provided by an embodiment of the present disclosure; Figure 8 This is a schematic diagram of a bonding scenario five provided in an embodiment of the present disclosure; Figure 9This is a schematic diagram of a bonding scenario provided in an embodiment of the present disclosure; Figure 10 This is a schematic diagram of the composite substrate structure provided in an embodiment of the present disclosure; Figure 11 A flowchart illustrating heating to a first preset temperature is provided as an embodiment of this disclosure; Figure 12 A flowchart illustrating the bonding of a first substrate and a second substrate, provided as an embodiment of this disclosure; Figure 13 This is a schematic diagram of a bonding device structure provided in an embodiment of the present disclosure; Figure 14 This is a schematic diagram of the structure of a first pressure plate and / or a second pressure plate provided in an embodiment of the present disclosure; Figure 15 This is a schematic diagram illustrating a substrate to be bonded exhibiting localized warping, as provided in an embodiment of this disclosure. Figure 16 A schematic diagram of another first pressure plate and / or second pressure plate provided in an embodiment of this disclosure; Figure 17 A schematic projection of a first pressure plate and a second pressure plate along the bonding pressure direction, provided for an embodiment of this disclosure; Figure 18 This is a schematic projection of another first pressure plate and second pressure plate along the bonding pressure direction, provided for an embodiment of this disclosure. Detailed Implementation

[0018] The technical solutions in some embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this disclosure are within the scope of protection of this disclosure.

[0019] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as open-ended and encompassing, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiment," "example," or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples.

[0020] Hereinafter, 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 indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more.

[0021] In describing some embodiments, the terms "coupled" and "connected," and their derivative expressions, may be used. The term "connected" should be interpreted broadly; for example, a "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection via an intermediate medium. The term "coupled," for example, indicates that two or more components have direct physical or electrical contact. The term "coupled" or "communicatively coupled" may also refer to two or more components that do not have direct contact with each other but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the content of this document.

[0022] In describing some embodiments, the term "connection" and its derivative expressions may be used. The term "connection" should be interpreted broadly; for example, "connection" can be a mechanical connection or an electrical connection; it can be a fixed connection or a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art will understand the specific meaning of the above terms herein based on the specific circumstances.

[0023] "At least one of A, B and C" has the same meaning as "at least one of A, B or C", both including the following combinations of A, B and C: only A, only B, only C, combinations of A and B, combinations of A and C, combinations of B and C, and combinations of A, B and C.

[0024] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0025] As used herein, depending on the context, the term “if” may optionally be interpreted as meaning “when”, “in the event of”, “in response to determination”, or “in response to detection”. Similarly, depending on the context, the phrase “if it is determined that…” or “if [the stated condition or event] is detected” may optionally be interpreted as meaning “in the event of determination that…”, “in response to determination that…”, “when [the stated condition or event] is detected”, or “in response to the detection of [the stated condition or event]”.

[0026] The use of “applies to” or “configured to” in this article implies an open and inclusive language that does not preclude applicability to or configuration to devices that perform additional tasks or steps.

[0027] In addition, the use of “based on” implies openness and inclusivity, because processes, steps, calculations or other actions “based on” one or more of the stated conditions or values ​​may in practice be based on additional conditions or values ​​beyond those stated.

[0028] As used herein, “about,” “approximately,” or “approximately” includes the stated value and the average value within an acceptable range of deviation from the given value, wherein the acceptable range of deviation is determined by a person skilled in the art taking into account the measurement under discussion and the error associated with the measurement of the given quantity (i.e., the limitations of the measurement system).

[0029] As used herein, “parallel,” “perpendicular,” and “equal” include the described situation and situations that are similar to the described situation, within an acceptable deviation range, which is determined by those skilled in the art taking into account the measurement under discussion and the errors associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, “parallel” includes absolute parallelism and approximate parallelism, where an acceptable deviation range for approximate parallelism may be, for example, within 5°; “perpendicular” includes absolute perpendicularity and approximate perpendicularity, where an acceptable deviation range for approximate perpendicularity may also be, for example, within 5°; “equal” includes absolute equality and approximate equality, where an acceptable deviation range for approximate equality may be, for example, a difference between the two equals being less than or equal to 5% of either one.

[0030] It should be understood that when a layer or element is referred to as being on another layer or substrate, it can mean that the layer or element is directly on the other layer or substrate, or that there is an intermediate layer between the layer or element and the other layer or substrate.

[0031] This document describes exemplary embodiments with reference to cross-sectional views and / or plan views, which are idealized exemplary drawings. In the drawings, the thickness of layers and the area of ​​regions are enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Thus, exemplary embodiments should not be construed as being limited to the shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing processes. For example, etched areas shown as rectangular would typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the areas of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0032] As used in this article, "cleanliness class" refers to the maximum number and size of suspended particles that are allowed to exist in a unit volume of air. "Cleanliness class 100" specifically means that there are no more than 100 suspended particles with a diameter of 0.5 μm or greater per cubic foot (approximately 28.3 liters) of air.

[0033] As a third-generation semiconductor material, silicon carbide (SiC) is widely used in 5G communications, aerospace and new energy vehicles due to its excellent bandgap, carrier saturation mobility, thermal conductivity, critical breakdown voltage and radiation resistance.

[0034] SiC single-crystal substrates are expensive, often accounting for more than 50% of the cost of semiconductor devices. After device fabrication, the substrate needs to be thinned by 100 μm to 200 μm to reduce resistance and thermal resistance, resulting in significant waste. Therefore, to avoid waste and reduce the cost of SiC substrates, SiC composite substrates are commonly used, which involve bonding a high-quality single-crystal SiC thin layer onto a lower-cost, lower-quality SiC substrate. During the fabrication of these composite substrates, a damage layer needs to be created in the high-quality SiC single-crystal substrate to facilitate the peeling of the thin layer after bonding. However, the damage layer causes stress changes in the high-quality SiC single-crystal substrate, leading to warping and deformation. This results in low yield, small bonding area, and poor bonding quality in the bonded SiC composite substrate, making it difficult to meet practical processing requirements.

[0035] In one related technology, double-sided ion implantation of the substrate is used to induce two damaged layers inside the substrate. The stress deformation generated by the two damaged layers cancels each other out, thereby alleviating the warpage problem caused by single-sided ion implantation. However, for SiC substrates, which consist of a carbon (C) facet and a silicon (Si) facet, since only the Si facet of the SiC substrate is used in semiconductor device fabrication, the actual composite substrate fabrication can only utilize the C facet for implantation and transfer of single-crystal thin layers (the C facet bonds, and the Si facet is exposed after peeling). Double-sided implantation wastes a lot of time during Si facet implantation. Subsequent processes often require chemical-mechanical polishing (CMP) to treat the Si facet of the substrate so that it can continue to serve as a donor to provide high-quality single-crystal SiC thin layers. Furthermore, since the substrate is used as a donor multiple times, the annealing process used in the multiple peeling processes causes the ions implanted on the Si facet to lose their surface shape control. After multiple composite substrate fabrications, the substrate needs to be ion implanted again to alleviate the warpage problem.

[0036] In view of the above-mentioned technical problems, one aspect of the present disclosure provides a method for preparing a composite substrate 100 to prepare a high-quality composite substrate 100.

[0037] Figure 1 This is a flowchart illustrating a method for preparing a composite substrate 100 according to an embodiment of the present disclosure.

[0038] like Figure 1 As shown, a method for preparing a composite substrate 100 according to an embodiment of this disclosure includes: S10. Prepare a first substrate 1, the first substrate 1 including a release layer 11.

[0039] S20, Obtain the second substrate 2.

[0040] Wherein, the defect density of the first substrate 1 is less than the defect density of the second substrate 2, and at least one of the first substrate 1 and / or the second substrate 2 is warped. The defect density of the first substrate 1 and the second substrate 2 referred to herein refers to the density of microtubes, dislocations or other possible crystal defects present in the substrate.

[0041] In some possible embodiments, fabricating the first substrate 1 includes ion implantation on a first side of the first substrate 1 to form a release layer 11, the release layer 11 being located within the first substrate 1. The first substrate 1 comprises SiC, and the release layer 11 divides the first substrate 1 into a substrate 12 and a functional layer 13. The portion of the first substrate 1 located away from the first side of the release layer 11 is the substrate 12, and the portion of the first substrate located closer to the first side of the release layer 11 is the functional layer 13. The first side surface of the first substrate 1 is the C-plane of the SiC substrate, and the other side surface of the first substrate 1 is the Si-plane of the SiC substrate. Due to the presence of the release layer 11, the first substrate 1 is subject to warping under internal stress.

[0042] In some possible implementations, hydrogen ion implantation or helium ion implantation can be used to ion implant the first substrate 1 to form the release layer 11. High-speed ions collide with lattice atoms at a specific depth within the first substrate 1, forming a collision cascade and generating numerous point defects. These point defects migrate and aggregate to form defect structures such as vacancy clusters and micropores, ultimately forming a Gaussian distribution layer enriched with implanted elements and exhibiting damage, i.e., the release layer 11. In addition to forming collision cascades with lattice atoms, hydrogen ion implantation or helium ion implantation can also enrich the release layer 11 at interstitial locations within the lattice of the lattice. Some hydrogen or helium ions combine with C vacancies to form stable complexes, while others aggregate at high concentrations to form nanoscale hydrogen or helium bubbles. In the subsequent annealing process, the diffusion of hydrogen or helium atoms is accelerated, the pressure inside the bubble increases sharply, and adjacent bubbles merge and grow, eventually forming a continuous microcrack network in the release layer 11. When the internal pressure exceeds the fracture strength of the SiC material, the cracks spread rapidly along the maximum shear stress surface (usually parallel to the substrate surface), causing the substrate 12 located on both sides of the release layer 11 to separate from the functional layer 13, thereby achieving the controllable transfer of high-quality SiC thin layers.

[0043] S30. Based on the warp direction of the first substrate 1, control the bonding pressure in different regions to bond the first substrate 1 and the second substrate 2 to form the third substrate 3.

[0044] In some possible implementations, such as Figure 2 As shown, S30 includes: S31~S32.

[0045] S31: Perform surface shape detection on the first substrate 1 and the second substrate 2 to obtain the warping direction of the first substrate 1 and the second substrate 2.

[0046] The warping direction of the first substrate 1 and the second substrate 2 includes forward warping, reverse warping, and no warping, and the warping direction of the first substrate 1 and the second substrate 2 is determined based on the bonding surface. As an example, forward warping means that the warping direction of the first substrate 1 or the second substrate 2 is towards the bonding surface; reverse warping means that the warping direction of the first substrate 1 or the second substrate 2 is away from the bonding surface.

[0047] For example, the first side surface of the first substrate 1 is the bonding surface, that is, the C surface of the first substrate 1 is the bonding surface, and the Si surface of the second substrate 2 is the bonding surface. The first substrate 1 is positively warped, that is, the warping direction of the first substrate 1 is towards the C surface, and the second substrate 2 is positively warped, that is, the warping direction of the second substrate 2 is towards the Si surface; the first substrate 1 is negatively warped, that is, the warping direction of the first substrate 1 is away from the C surface, and the warping direction of the second substrate 2 is away from the Si surface.

[0048] S32, Bond the first substrate 1 and the second substrate 2 together.

[0049] The first substrate 1 and the second substrate 2 are placed at 10 -6 Bonding is performed in an environment with a cleanliness level of 100 or higher, and the bonding time is 30 to 60 seconds.

[0050] Among them, such as Figure 3 As shown, the bonding pressure determination method used in the bonding process of the first substrate 1 and the second substrate 2 includes S321~S325.

[0051] S321. When the warping directions of the first substrate 1 and the second substrate 2 are opposite, the bonding pressure on the first substrate 1 and / or the second substrate 2 remains unchanged along the direction from the center of the first substrate 1 to the edge.

[0052] As an example, such as Figure 4 As shown, the first substrate 1 is warped in the forward direction and the second substrate 2 is warped in the reverse direction. After aligning the first substrate 1 and the second substrate 2, the bonding surfaces of the first substrate 1 and the second substrate 2 are bonded together. During bonding, bonding pressure is applied to different regions at the same time, and the bonding pressure applied to different regions remains unchanged.

[0053] For example, bonding can be performed by applying bonding pressure from one side of the first substrate 1, in which case the bonding pressure is applied to the first substrate 1; bonding can also be performed by applying bonding pressure from one side of the second substrate 2, in which case the bonding pressure is applied to the second substrate 2; or bonding can be performed by applying bonding pressure from opposite sides of the first substrate 1 and the second substrate 2, in which case the bonding pressure is applied to both the first substrate 1 and the second substrate 2. This disclosure does not specifically limit the embodiments in this way.

[0054] S322. When the warping directions of the first substrate 1 and the second substrate 2 are the same, and the warping direction of the first substrate 1 is towards the second substrate 2, the bonding pressure on the first substrate 1 and / or the second substrate 2 decreases sequentially along the direction from the center of the first substrate 1 to the edge.

[0055] As an example, such as Figure 5 As shown, the first substrate 1 is positively warped, and the second substrate 2 is positively warped. After aligning the first substrate 1 and the second substrate 2, there is a gap between the first substrate 1 and the second substrate 2, and the gap exhibits the characteristic of being larger in the center and smaller at the edges. During bonding, by first applying a larger bonding pressure to the area with a larger gap near the center, and then successively applying a smaller bonding pressure to the area with a smaller gap near the edges, the first substrate 1 and the second substrate 2 are driven to undergo non-uniform controllable deformation to compensate for the warping. This makes the first substrate 1 and the second substrate 2 become parallel to each other after being pressed, thereby reducing the risk of local mechanical damage or bubbles and improving the bonding quality.

[0056] In this embodiment, the bonding pressure on the first substrate 1 and / or the second substrate 2 decreases sequentially along the direction from the center of the first substrate 1 to the edge. This can be achieved by the bonding pressure decreasing in a regional gradient along the direction from the center of the first substrate 1 to the edge; or by the bonding pressure decreasing linearly along the direction from the center of the first substrate 1 to the edge. This embodiment does not specifically limit this aspect. The bonding method of the first substrate 1 and the second substrate 2 can be referred to in S321, and will not be repeated here.

[0057] S323. When the warping directions of the first substrate 1 and the second substrate 2 are the same, and the warping direction of the first substrate 1 is away from the second substrate 2, the bonding pressure on the first substrate 1 and / or the second substrate 2 increases sequentially along the direction from the center of the first substrate 1 to the edge.

[0058] As an example, such as Figure 6 As shown, the first substrate 1 is warped in the opposite direction and the second substrate 2 is warped in the opposite direction. After aligning the first substrate 1 and the second substrate 2, there is a gap between the first substrate 1 and the second substrate 2, and the gap exhibits the characteristic of being small in the center and large at the edges. At this time, in order to compensate for the warping, a larger bonding pressure is first applied to the area with a larger gap near the edge, and then a smaller bonding pressure is applied to the area with a smaller gap near the center.

[0059] In this embodiment, the bonding pressure on the first substrate 1 and / or the second substrate 2 increases sequentially along the direction from the center of the first substrate 1 to the edge. This can be achieved by the bonding pressure on the first substrate 1 and / or the second substrate 2 increasing in a regional gradient along the direction from the center of the first substrate 1 to the edge; or by the bonding pressure on the first substrate 1 and / or the second substrate 2 increasing linearly along the direction from the center of the first substrate 1 to the edge. This embodiment does not specifically limit this aspect. The bonding method of the first substrate 1 and the second substrate 2 can be referred to in S321, and will not be repeated here.

[0060] S324. When the second substrate 2 is not warped and the warping direction of the first substrate 1 is towards the second substrate 2, the bonding pressure on the first substrate 1 and / or the second substrate 2 decreases sequentially along the direction from the center of the first substrate 1 to the edge.

[0061] As an example, such as Figure 7As shown, the first substrate 1 is warped in the forward direction, while the second substrate 2 is not warped. After aligning the first substrate 1 and the second substrate 2, a gap exists between them, exhibiting a characteristic of being larger at the center and smaller at the edges. To compensate for the warping, a larger bonding pressure is first applied to the region with a larger gap closer to the center, and then a smaller bonding pressure is sequentially applied to the region with a smaller gap closer to the edges. The method of applying the bonding pressure can be referred to in S322, and will not be repeated here in this embodiment.

[0062] S325. When the second substrate 2 is not warped and the warping direction of the first substrate 1 is away from the second substrate 2, the bonding pressure on the first substrate 1 and / or the second substrate 2 increases sequentially along the direction from the center of the first substrate 1 to the edge.

[0063] As an example, such as Figure 8 As shown, the first substrate 1 is warped in the reverse direction, while the second substrate 2 is not warped. After aligning the first substrate 1 and the second substrate 2, a gap exists between them, exhibiting a characteristic of being smaller at the center and larger at the edges. To compensate for the warping, a larger bonding pressure is first applied to the area near the edge where the gap is larger, and then a smaller bonding pressure is sequentially applied to the area near the center where the gap is smaller. The method of applying the bonding pressure can be referred to in S323, and will not be repeated here in this embodiment.

[0064] In some examples, such as Figure 9 As shown, the warping of one edge of the first substrate 1 and / or the second substrate 2 is greater than that of the other edge. After aligning the first substrate 1 and the second substrate 2, a gap exists between them, with the gap being larger on one edge and decreasing along that edge towards the contact point. Similarly, the gap decreases along the other edge towards the contact point, but the degree of decrease differs on both sides of the contact point. To compensate for the warping, a greater bonding pressure is applied to the area farther from the contact point with a larger gap, and a smaller bonding pressure is applied to the area closer to the contact point with a smaller gap. Specifically, a greater bonding pressure can be applied first to the area farther from the contact point with a larger gap, followed by a progressively smaller bonding pressure applied to the area closer to the edge with a smaller contact point gap.

[0065] Specifically, along the direction from the edge with the larger gap to the contact point, the bonding pressure on the first substrate 1 and / or the second substrate 2 decreases sequentially, while along the direction from the contact point to the other edge, the bonding pressure on the first substrate 1 and / or the second substrate 2 increases sequentially.

[0066] Figures 4-9 The length of the middle arrow indicates the magnitude of the bond force applied.

[0067] S40. A portion of the first substrate 1 is peeled off along the peeling layer 11 to form a composite substrate 100.

[0068] In some possible implementations, S40 includes: S41.

[0069] S41. The third substrate 3 is heated to a first preset temperature and kept at that temperature for a first preset time, so that the third substrate 3 breaks along the direction of the release layer 11.

[0070] As an example, a third substrate 3 formed by bonding a first substrate 1 and a second substrate 2 can be placed in an annealing furnace. The temperature of the annealing furnace is raised from room temperature to a first preset temperature and held at that temperature for a first preset time. The first preset temperature is 800℃~1000℃. For example, in this embodiment, the first preset temperature can be any one of 800℃, 850℃, 900℃, 950℃, or 1000℃. The first preset time is 80 min~100 min. For example, in this embodiment, the first preset time can be any one of 80 min, 85 min, 90 min, 95 min, or 100 min; this embodiment does not specifically limit this.

[0071] Within this temperature range, hydrogen or helium atoms in the release layer 11 can gain sufficient energy to begin active migration, accumulating and combining at lattice defects to form molecular states, resulting in numerous nanoscale bubbles. As the holding time increases, the internal pressure of the bubbles increases, generating tensile stress in the release layer 11. When the tensile stress exceeds the local strength of the substrate material, the substrate undergoes plastic deformation and fractures, forming microcracks that extend along the extension direction of the release layer 11 with increasing holding time. After sufficient holding time, the extended microcracks connect and merge, forming a macroscopic crack plane penetrating the third substrate 3, thus completing the separation of the functional layer 13 from the substrate 12, resulting in the composite substrate 100. Figure 10 As shown, the composite substrate 100 includes a bonded second substrate 2 and a functional layer 13.

[0072] In some possible implementations, the substrate 12 can be cleaned and polished to reduce the roughness of the C-surface of the substrate 12 to below 0.2 nm, so that it can continue to be reused as a donor.

[0073] In some possible implementations, such as Figure 11 As shown, S41 includes: S411~S412.

[0074] S411. The third substrate 3 is heated to a second preset temperature and kept at that temperature for a second preset time, thereby enhancing the bonding force between the first substrate 1 and the second substrate 2.

[0075] As an example, a third substrate 3 formed by bonding a first substrate 1 and a second substrate 2 can be placed in an annealing furnace. The temperature of the annealing furnace is raised from room temperature to a second preset temperature and held at that temperature for a second preset time. The second preset temperature is 350°C to 500°C. For example, in this embodiment, the second preset temperature can be any one of 350°C, 400°C, 450°C, or 500°C. The second preset time is 45 min to 75 min. For example, in this embodiment, the second preset time can be any one of 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, or 75 min. This embodiment does not specifically limit the duration of the duration.

[0076] Within this temperature range, trace amounts of water vapor and residual contaminants adsorbed at the bonding interface between the first substrate 1 and the second substrate 2 desorb and escape, reducing the impact of interface impurities and defects on the bonding strength. At the same time, it enables the atoms at the bonding interface to acquire sufficient ability to undergo short-range diffusion, promoting the transformation of the bonding interface, which was originally based on weak interactions such as van der Waals forces and hydrogen bonds, into strong covalent bonds. In addition, this holding time can effectively release the internal stress caused by the difference in thermal expansion coefficients during the bonding process, reducing the risk of the generation and propagation of microcracks at the bonding interface, thereby enhancing the bonding force between the first substrate 1 and the second substrate 2.

[0077] S412. Heat the second preset temperature to the first preset temperature.

[0078] The second preset temperature is heated to the first preset temperature and held at that temperature for a first preset time to complete the separation of the composite substrate 100 from the substrate 12.

[0079] In some possible implementations, the method for preparing the composite substrate 100 further includes steps S50 to S60.

[0080] S50. The composite substrate 100 is heated to a third preset temperature and kept at that temperature for a third preset time to improve the quality of the composite substrate 100.

[0081] As an example, the composite substrate 100 can be placed in an annealing furnace, and the temperature of the annealing furnace can be raised from room temperature to a third preset temperature and held at that temperature for a third preset time. The third preset temperature is 1300℃ to 1750℃. For example, in this embodiment, the third preset temperature can be any one of 1300℃, 1350℃, 1400℃, 1450℃, 1500℃, 1550℃, 1600℃, 1650℃, 1700℃, or 1750℃. The third preset time is 5 min to 10000 min, and the third preset time can be set according to the initial mass of the prepared composite substrate 100. This embodiment does not impose specific limitations on this.

[0082] Maintaining the temperature within this range can effectively repair lattice defects such as dislocations, stacking faults, and vacancies generated during the preparation and bonding process of the composite substrate 100. By migrating, annihilating, and rearranging defect atoms, the defect density is reduced, thereby improving the quality of the composite substrate 100. It can also promote the consistency of the lattice orientation between the functional layer 13 and the second substrate 2, reduce lattice distortion at the bonding interface, and improve the overall electrical uniformity and thermal conductivity consistency of the composite substrate 100.

[0083] S60. Polish the functional surfaces of the composite substrate 100.

[0084] The functional surface of the composite substrate 100 is the surface exposed after the third substrate 3 is partially stripped from the first substrate 1 (i.e., substrate 12). The functional surface of the composite substrate 100 prepared by S10~S40 has high roughness and cannot be directly used for epitaxial layer growth or semiconductor device fabrication. Therefore, the functional surface of the composite substrate 100 needs to be polished to reduce the surface roughness of the functional surface to below 0.2 nm.

[0085] In some possible implementations, such as Figure 12 As shown, before bonding the first substrate 1 and the second substrate 2, the process further includes: S33. Perform surface activation treatment on the bonding surface of the first substrate 1 and the bonding surface of the second substrate 2.

[0086] By bombarding the bonding surfaces of the first substrate 1 and the second substrate 2 with high-energy particles, the original chemical bonds of the atoms on the bonding surfaces are broken, a large number of active groups are generated and the internal atomic layers are exposed, thereby enhancing the surface activity of the bonding surfaces. In the subsequent bonding process, stable covalent bonds are formed through the chemical reaction of the active groups, further improving the bonding effect.

[0087] As an example, the bonding surface can be activated by irradiating it with Fast Atom Bombardment (FAB) for 10 s to 10000 s.

[0088] In another aspect of this disclosure, a bonding apparatus 200 is provided for implementing partitioned bonding. This apparatus can be applied to the fabrication method of the composite substrate 100 described above, meaning that the bonding apparatus 200 can be used to control the bonding pressure of the first substrate 1 and the second substrate 2. For example... Figure 13 , Figure 14 and Figure 16 As shown, the bonding device 200 includes a first pressure plate 210 and a second pressure plate 220 disposed opposite to each other, and the first pressure plate 210 and / or the second pressure plate 220 includes a plurality of separately disposed sub-pressure plates 230. It should be understood that... Figure 13 , Figure 14 and Figure 16The shapes of the first pressure plate 210, the second pressure plate 220, and the sub-pressure plate 230 shown are merely examples and do not constitute a limitation on the shapes of the first pressure plate 210, the second pressure plate 220, and the sub-pressure plate 230.

[0089] In some examples, the first pressure plate 210 is a one-piece structure, and the second pressure plate 220 includes multiple separately arranged sub-pressure plates 230; in other examples, the first pressure plate 210 includes multiple separately arranged sub-pressure plates 230, and the second pressure plate 220 is a one-piece structure; in still other examples, both the first pressure plate 210 and the second pressure plate 220 include multiple separately arranged sub-pressure plates 230. By applying different bonding pressures to the multiple sub-pressure plates 230, partitioned bonding of the substrates to be bonded (such as the first substrate 1 and the second substrate 2 mentioned above) is achieved.

[0090] As an example, the first pressure plate 210 and the second pressure plate 220 are made of any of the following materials: metal, piezoelectric ceramic or graphite, and a preset pressure can be provided to the first pressure plate 210 and / or the second pressure plate 220 by any of the following methods: mechanical pressure head, air pressure head or hydraulic pressure head.

[0091] In some possible implementations, the bonding device 200 further includes a control device 240 connected to the first pressure plate 210 and the second pressure plate 220, the control device 240 being configured to control the pressure applied by each sub-pressure plate 230.

[0092] As an example, such as Figure 14 As shown, the first pressing plate 210 is square in shape, the second pressing plate 220 is square in shape, and the sub-pressing plates 230 are square in shape, with multiple sub-pressing plates 230 arranged in an array. For example, see [link to relevant documentation]. Figure 13 The first pressure plate 210 or the second pressure plate 220 includes 100 sub-pressure plates 230, which can provide different bonding pressures for 100 partitions of the substrate to be bonded (e.g., the first substrate 1 and the second substrate 2).

[0093] As an example, such as Figure 15 As shown, when bonding the first substrate 1 and the second substrate 2, local warping occurs at points A and B. Warping is greater at point A, resulting in a larger gap between the first substrate 1 and the second substrate 2; warping is less at point B, resulting in a smaller gap between the first substrate 1 and the second substrate 2. In this case, the sub-pressure platen 230 corresponding to the bonding region at point A applies a greater bonding pressure to that region; and the sub-pressure platen 230 corresponding to the bonding region at point B applies a smaller bonding pressure to that region.

[0094] In some possible implementations, such as Figure 16As shown, the multiple sub-pressure plates 230 include a central sub-pressure plate 231 and peripheral sub-pressure plates 232, with the peripheral sub-pressure plates 232 surrounding the central sub-pressure plate 231.

[0095] As an example, such as Figure 16 As shown, the central sub-pressing plate 231 is an integrally formed structure. Taking a circular shape as an example, the outer sub-pressing plates 232 are annular in shape, and the inner diameter of the outer sub-pressing plate 232A adjacent to the central sub-pressing plate 231 matches the diameter of the central sub-pressing plate 231. The number of outer sub-pressing plates 232 can be multiple. Along the direction from the center of the first pressing plate 210 or the second pressing plate 220 towards the edge, the outer diameter of the innermost outer sub-pressing plate 232B matches the inner diameter of the outermost outer sub-pressing plate 232C adjacent to it. The shape of the central sub-pressing plate 231 can also be quadrilateral, octagonal, hexagonal, etc., and the shape of the outer sub-pressing plates 232 is an annular shape that matches the shape of the central sub-pressing plate 231. This embodiment does not specifically limit the shape in this respect.

[0096] In some possible implementations, such as Figure 17 As shown, both the first pressure plate 210 and the second pressure plate 220 include multiple separately arranged sub-pressure plates 230. The projection of the sub-pressure plate 230 of the first pressure plate 210 along the bonding pressure direction coincides with the projection of the sub-pressure plate 230 of the second pressure plate 220.

[0097] Using the above method, the sub-plates 230 of the first pressure plate 210 and the sub-plates 230 of the second pressure plate 220 can divide the bonding area into multiple bonding areas that match the shape of the sub-plates 230. Each bonding area can be individually bonded with independent bonding pressure to perform partitioned bonding of the substrate to be bonded.

[0098] As an example, such as Figure 16 As shown, when the number of sub-plates 230 in the first pressure plate 210 and the second pressure plate 220 is 6, taking the first pressure plate 210 as an example, it includes a central sub-plate 231 and peripheral sub-plates 232A, 232B, 232C, 232D and 232E. When bonding the substrate to be bonded, the central sub-plate 231 applies a bonding pressure of 60 kN, the peripheral sub-plate 232A applies a bonding pressure of 65 kN, the peripheral sub-plate 232B applies a bonding pressure of 70 kN, the peripheral sub-plate 232C applies a bonding pressure of 75 kN, the peripheral sub-plate 232D applies a bonding pressure of 80 kN, and the peripheral sub-plate 232E applies a bonding pressure of 85 kN.

[0099] In some possible implementations, such as Figure 18As shown, both the first pressure plate 210 and the second pressure plate 220 include multiple separately arranged sub-pressure plates 230. The gap between the multiple sub-pressure plates 230 of the first pressure plate 210 is a first gap 260, and the gap between the multiple sub-pressure plates 230 of the second pressure plate 220 is a second gap 270. The projections of the first gap 260 and the second gap 270 along the bonding pressure direction are arranged alternately.

[0100] Using the above method, the first gap 260 and the second gap 270 can divide more bonding areas without increasing the number of sub-pressure plates 230, providing more precise partitioned bonding pressure for the substrate to be bonded.

[0101] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A bonding device, characterized in that, include: A first pressure plate and a second pressure plate are arranged opposite to each other, wherein the first pressure plate and / or the second pressure plate includes a plurality of separately arranged sub-pressure plates; A control device is connected to the first pressure plate and the second pressure plate; the control device is configured to control the pressure applied by each of the sub-pressure plates.

2. The bonding apparatus according to claim 1, characterized in that, The plurality of sub-pressure plates include a central sub-pressure plate and peripheral sub-pressure plates, wherein the peripheral sub-pressure plates surround the central sub-pressure plate.

3. The bonding apparatus according to claim 2, characterized in that, Both the first pressure plate and the second pressure plate include multiple sub-pressure plates that are separately arranged; Along the bonding pressure direction, the projection of the sub-plate of the first pressure plate coincides with the projection of the sub-plate of the second pressure plate.

4. The bonding apparatus according to claim 1, characterized in that, Both the first pressure plate and the second pressure plate include multiple separately configured sub-pressure plates; Wherein, the gap between the multiple sub-plates of the first pressure plate is the first gap, and the gap between the multiple sub-plates of the second pressure plate is the second gap; along the bonding pressure direction, the projections of the first gap and the projections of the second gap are arranged alternately.

5. A method for preparing a composite substrate, characterized in that, include: A first substrate is prepared, the first substrate including a release layer; Obtain a second substrate; the defect density of the first substrate is less than the defect density of the second substrate; and at least one of the first substrate and / or the second substrate is warped; Based on the warp direction of the first substrate, the bonding pressure in different regions is controlled to bond the first substrate and the second substrate together to form a third substrate; A portion of the first substrate is peeled off along the peeling layer to form a composite substrate.

6. The method for preparing a composite substrate according to claim 5, characterized in that, The step of controlling the bonding pressure in different regions according to the warp direction of the first substrate to bond the first substrate and the second substrate to form a third substrate includes: The first substrate and the second substrate are subjected to surface shape detection to obtain the warping direction of the first substrate and the second substrate; Bond the first substrate and the second substrate together; When the warping directions of the first substrate and the second substrate are opposite, the bonding pressure on the first substrate and / or the second substrate remains unchanged along the direction from the center of the first substrate to the edge. When the first substrate and the second substrate have the same warp direction, and the warp direction of the first substrate is towards the second substrate, the bonding pressure on the first substrate and / or the second substrate decreases sequentially along the direction from the center of the first substrate to the edge. When the first substrate and the second substrate have the same warp direction, and the warp direction of the first substrate is away from the second substrate, the bonding pressure on the first substrate and / or the second substrate increases sequentially along the direction from the center of the first substrate to the edge. When the second substrate does not warp and the warping direction of the first substrate is towards the second substrate, the bonding pressure on the first substrate and / or the second substrate decreases sequentially along the direction from the center of the first substrate to the edge. When the second substrate does not warp and the warping direction of the first substrate is away from the second substrate, the bonding pressure on the first substrate and / or the second substrate increases sequentially along the direction from the center of the first substrate to the edge.

7. The method for preparing a composite substrate according to claim 5, characterized in that, The preparation of the first substrate includes: Ion implantation is performed on a first side of the first substrate to form the release layer; the release layer is located within the first substrate, and the portion of the first substrate located away from the first side of the release layer is the substrate, while the portion of the first substrate located near the first side of the release layer is the functional layer.

8. The method for preparing a composite substrate according to claim 7, characterized in that, The stripped portion of the first substrate includes: The third substrate is heated to a first preset temperature and held at that temperature for a first preset time, causing the third substrate to break along the direction of the release layer.

9. The method for preparing a composite substrate according to claim 8, characterized in that, Heating the third substrate to a first preset temperature includes: The third substrate is heated to a second preset temperature and held at that temperature for a second preset time, thereby enhancing the bonding force between the first substrate and the second substrate. The second preset temperature is heated to the first preset temperature.

10. The method for preparing a composite substrate according to claim 5, characterized in that, After the first substrate is partially stripped to form a composite substrate, the process further includes: The composite substrate is heated to a third preset temperature and held at that temperature for a third preset time to improve the quality of the composite substrate. The functional surface of the composite substrate is polished, and the functional surface is the surface exposed after the third substrate partially peels off the first substrate.

11. The method for preparing a composite substrate according to any one of claims 5 to 10, characterized in that, Before bonding the first substrate and the second substrate, the method further includes: The bonding surfaces of the first substrate and the second substrate are subjected to surface activation treatment.

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