A method for manufacturing a bonding structure, a bonding structure, a bonding apparatus

Abstract

The application belongs to the technical field of semiconductor manufacturing, and provides a bonding structure preparation method, a bonding structure and a bonding device. The bonding structure preparation method comprises forming a third material on a first material and / or a second material to be bonded, and then bonding the first material and the second material through the third material after specific freezing activation treatment, temperature recovery treatment and activation treatment are sequentially performed, to obtain a bonding structure. Bonding through the separately formed third material is conducive to making the third material obtain a smaller thickness, i.e., forming a thin layer. The cooperation of the freezing activation treatment, the temperature recovery treatment and the activation treatment can reduce damage to the third material while making it obtain sufficient interface bonding capability, so that the preparation method can be used to prepare a silicon-on-insulator structure with a thin insulating isolation layer and no electric leakage.

Description

Technical Field

[0001] This application belongs to the field of semiconductor processing technology and relates to a method for preparing a bonding structure, a bonding structure, and a bonding apparatus. Background Technology

[0002] Silicon-on-Insulator (SOI) structures solve many of the pain points of traditional bulk silicon devices by introducing an insulating isolation layer between the top silicon layer and the silicon substrate, and are widely used in high-end logic chips and power semiconductor devices.

[0003] In existing silicon-on-insulator (SiI) structures, the thickness of the insulating layer is typically above 50 nm. Thicker insulating layers help reduce leakage current but increase interfacial thermal resistance. While thinner insulating layers can reduce interfacial thermal resistance, thinner layers are prone to forming a damage layer at the interface between the insulating layer and the silicon substrate after plasma activation during the bonding process, leading to leakage and loss of insulation effectiveness. Summary of the Invention

[0004] In view of the problems existing in the prior art, the purpose of this application is to provide a method for preparing a bonding structure, a bonding structure, and a bonding device. The preparation method can be used to prepare a silicon-on-insulator structure with a thin insulating layer and no leakage current.

[0005] To achieve this objective, the following technical solution is adopted in this application:

[0006] In a first aspect, some embodiments of this application provide a method for preparing a bonding structure, the method comprising:

[0007] A first material and a second material are provided to be bonded; a third material is disposed on the bonding surfaces of the first material and / or the second material.

[0008] The bonding surfaces of the first material and the second material are activated, wherein the activation temperature of the first material and / or the second material, on which the third material is disposed, is less than or equal to 0°C.

[0009] The temperature of the first material and the second material is kept above the ambient dew point temperature. An activation process is performed on one side of the surface of the first material and the second material to be bonded. Then, a bonding process is performed to obtain a bonded structure.

[0010] In the bonding structure preparation method described in this application, the third material formed on the first material and / or the second material to be bonded, and the bonding through the third material, is beneficial for the separately formed third material to obtain a smaller thickness, i.e., to form a thin layer. At the same time, by sequentially subjecting the third material to specific freezing (low temperature) activation treatment (i.e., activation treatment at a temperature less than or equal to 0°C), heating recovery treatment (i.e., making the temperature of the first material and the second material higher than the ambient dew point temperature and maintaining it), and activation treatment, sufficient interfacial bonding ability can be obtained while reducing damage to the third material. Therefore, the preparation method can be used to prepare silicon-on-insulator structures with thin insulating isolation layers and no leakage current.

[0011] Specifically, this application breaks the chemical bonds on the material surface through activation treatment to form unsaturated bonds, facilitating the subsequent activation treatment to combine substances containing hydroxyl (-OH) or carboxyl (-COOH) groups. This gives the surface to be bonded hydrophilic dangling bonds or dangling groups. After activation, these hydrophilic dangling bonds or dangling groups can form hydrogen bonds through adsorbed water molecules at the moment of bonding, causing the first and second materials to adhere and bond together, thereby achieving bonding. Therefore, the bonding implemented by the preparation method described in this application is a hydrophilic bonding. Hydrophilic bonding can be achieved through an intermediate film layer (i.e., the third material), broadening the compatibility with materials. Furthermore, hydrophilic bonding can be carried out in atmospheric or low-vacuum environments, without the need for a high-vacuum environment, reducing the severity of process conditions and facilitating industrial manufacturing.

[0012] The following are preferred embodiments of this application, but are not intended to limit the technical solutions provided in this application. The technical objectives and beneficial effects of this application can be better achieved through the technical solutions of the following embodiments.

[0013] In some embodiments of this application, both the first material and the second material comprise silicon.

[0014] In some embodiments of this application, the third material includes an insulating material, which includes at least one of SiO2, SiC, SiCN, Al2O3, HfO2, AlN, or SiN.

[0015] In some embodiments of this application, when the third material is disposed on the bonding surfaces of the first material and / or the second material, the total thickness of the third material is <10 nm. For example, the total thickness of the third material can be 9.8 nm, 8 nm, 7 nm, 6 nm, 5 nm, 4 nm, 3 nm, 2 nm, or 1 nm, etc.

[0016] In some embodiments of this application, the method of depositing a third material on the bonding surface of the first material and / or the second material includes at least one of sputtering deposition, chemical vapor deposition (CVD), atomic layer deposition (ALD), or thermal oxidation.

[0017] In some embodiments of this application, the activation process includes plasma activation.

[0018] During plasma activation, high-energy particles generated by the plasma bombard the material film (such as a third material), creating holes. Most of these holes are generated on the surface and migrate into the interior of the third material or to the interface between the third material and the first or second material via diffusion or drift. Some holes are trapped in the interface region, becoming captured positive charges, while others recombine with electrons, releasing energy and breaking the chemical bonds in the interface region, creating silicon dangling bonds and forming interface traps. These interface traps can lead to leakage current. This phenomenon occurs less frequently in thicker material films because the diffusion or drift distance of holes is limited, and they remain trapped within the film, preventing diffusion or drift to the interface. However, thinner material films are easily diffused to the interface by holes. Therefore, this application uses a freezing process to lower the material temperature, weakening the material lattice vibration and suppressing hole diffusion during activation, thus allowing the third material to achieve both thinness and zero leakage current.

[0019] As a further example, the plasma activation power in the plasma activation process is 50W~200W, for example, it can be 50W, 80W, 100W, 120W, 140W, 160W, 180W or 200W, etc.; the activation time is 30s~60s, for example, it can be 30s, 35s, 40s, 45s, 50s, 55s or 60s, etc.; the working gas may optionally include argon (Ar).

[0020] In some embodiments of this application, the preparation method further includes: freezing the first material and / or the second material on which the third material is disposed before and / or during the activation treatment, so that the temperature of the first material and / or the second material on which the third material is disposed is kept at less than or equal to 0°C.

[0021] This application allows the material to be cooled to a target temperature and maintained before activation, or cooling to occur during activation. Regardless of the method used for freezing, the freezing process must bring the material temperature to 0°C or below, for example, any value between -273°C and 0°C, such as -273°C, -270°C, -250°C, -220°C, -200°C, -170°C, -150°C, -120°C, -100°C, -80°C, -50°C, -30°C, -10°C, -5°C, or 0°C. The specific temperature reached during freezing can be adjusted adaptively according to the thickness of the third material and the degree of activation. To minimize the risk of the thin third material failing to insulate due to activation, the freezing temperature can be relatively low. However, the energy consumption and cost of both the freezing process and subsequent heating should be considered.

[0022] In some embodiments of this application, raising the temperature of the first material and the second material above the ambient dew point temperature includes restoring the temperature of the first material and the second material to room temperature (15°C to 35°C). Exemplarily, the temperature to restore to room temperature can be 15°C, 18°C, 20°C, 22°C, 25°C, 28°C, 30°C, 32°C, or 35°C, etc.

[0023] In this application, materials that have undergone freezing treatment and are at a low temperature are heated to restore them to a temperature above the ambient dew point or further to room temperature (15°C to 35°C). This avoids condensation on the material surface during subsequent processes in an atmospheric (non-vacuum) or low-vacuum environment, preventing the formation or retention of excess moisture. This also prevents excess moisture from forming bubbles at the bonding interface, thus avoiding impacts on bonding effectiveness and quality. The ambient dew point temperature refers to the dew point temperature of the process environment in which the heating, activation, and bonding treatments take place; it can be ≥10°C, but is typically best kept between 10°C and 15°C.

[0024] In some embodiments of this application, the activation process includes wet treatment followed by drying.

[0025] In some embodiments of this application, the wet treatment liquid includes at least one of water (H2O), formic acid (CH2O2) or ethanol (C2H6O); the water may further be deionized water.

[0026] In some embodiments of this application, the wet treatment method includes spraying and / or soaking.

[0027] In some embodiments of this application, the drying method includes spin drying and / or blowing.

[0028] In this application, after activation treatment, a wet treatment is used to adsorb hydrophilic molecules (such as water molecules) onto the activated surface with dangling bonds or dangling groups. Hydrogen bonds are then formed at the bonding interface by these hydrophilic molecules, thus achieving bonding. Therefore, the wet treatment activates the hydrophilic bonding. It is understood that the wet activation process can be completed in a short time, simply until surface adsorption reaches saturation, and can be adjusted appropriately according to actual conditions. In this application, the drying treatment aims to remove excess hydrophilic molecules, such as water, to prevent the formation of bubbles at the bonding interface, which would affect the bonding effect and quality.

[0029] In some embodiments of this application, the vacuum degree of the activation treatment is 0.1 Pa to 200 Pa. Exemplarily, it can be 0.1 Pa, 0.3 Pa, 0.8 Pa, 1 Pa, 3 Pa, 5 Pa, 8 Pa, 10 Pa, 30 Pa, 50 Pa, 80 Pa, 100 Pa, 120 Pa, 140 Pa, 160 Pa, 180 Pa, or 200 Pa, etc.

[0030] And / or, the vacuum degree of the bonding process is 0.05 Pa to 200 Pa. Exemplarily, it can be 0.05 Pa, 0.08 Pa, 0.1 Pa, 0.3 Pa, 0.5 Pa, 0.8 Pa, 1 Pa, 3 Pa, 5 Pa, 8 Pa, 10 Pa, 30 Pa, 50 Pa, 80 Pa, 100 Pa, 130 Pa, 150 Pa, 180 Pa, or 200 Pa, etc.

[0031] In this application, the aforementioned heating treatment, activation treatment and bonding treatment can all be carried out in a low vacuum environment.

[0032] In some embodiments of this application, the preparation method further includes: after the bonding treatment, performing an annealing treatment to obtain the bonding structure.

[0033] In some embodiments of this application, the bonding process includes pre-bonding at 15°C to 35°C (room temperature), for example, 15°C, 18°C, 20°C, 22°C, 25°C, 28°C, 30°C, 32°C, or 35°C. Depending on the material and process, the pressure applied during pre-bonding can be 0.1N to 500N. For example, if pre-bonding is performed by point pressure, the applied pressure can be 0.1N, 0.2N, 0.5N, 1N, 1.5N, 2N, 3N, 5N, or 10N; or if pre-bonding is performed by surface pressure, the applied pressure can be 20N, 50N, 80N, 100N, 150N, 200N, 300N, or 500N.

[0034] In some embodiments of this application, the annealing treatment temperature is 100℃~450℃, and the time is 1h~24h. For example, the annealing treatment temperature can be 100℃, 130℃, 150℃, 200℃, 220℃, 250℃, 300℃, 330℃, 350℃, 380℃, 400℃, 420℃, or 450℃, and the time can be 1h, 3h, 5h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, or 24h, etc.

[0035] In this application, after the bonding process is performed, the bonded sample is subjected to low-temperature heat treatment, which helps to promote the evaporation of water molecules on the bonding interface, causing adjacent hydrophilic groups (such as -Si-OH) to undergo dehydration condensation and form stable covalent bonds, such as -Si-OH transforming into Si-O-Si, thereby improving the bonding effect and enhancing the bonding quality.

[0036] Secondly, in some embodiments of this application, a bonding structure is provided, which is obtained according to the preparation method described in the first aspect; the bonding structure includes a first material, a third material, and a second material stacked together.

[0037] In some embodiments of this application, both the first material and the second material comprise silicon.

[0038] In some embodiments of this application, the third material includes an insulating material, which includes at least one of SiO2, SiC, SiCN, Al2O3, HfO2, AlN, or SiN.

[0039] In some embodiments of this application, the total thickness of the third material is <10nm. Exemplarily, the total thickness of the third material may be 9.8nm, 8nm, 7nm, 6nm, 5nm, 4nm, 3nm, 2nm, or 1nm, etc.

[0040] In some embodiments of this application, the bonding structure includes a silicon-on-insulator structure.

[0041] Thirdly, in some embodiments of this application, a bonding apparatus is provided for performing the preparation method described in the first aspect embodiment, or for preparing the bonding structure of the second aspect embodiment, the bonding apparatus including a transfer chamber, and further comprising:

[0042] A freeze-activation chamber is configured to freeze a first material and / or a second material on which a third material is disposed, and to activate the first material and the second material, and is connected to the transfer chamber.

[0043] An activation device configured to activate the first material and the second material;

[0044] A bonding chamber is configured to perform bonding processing on the first material and the second material to obtain a bonding structure, and is connected to the transport chamber.

[0045] In some embodiments of this application, the transfer chamber includes a robotic arm for transferring materials.

[0046] In some embodiments of this application, a film-forming chamber is also included, which includes at least one of a sputtering deposition apparatus, a chemical vapor deposition apparatus, or an atomic layer deposition apparatus.

[0047] In some embodiments of this application, the cryo-activation chamber includes a plasma excitation device and a chuck, the chuck being used to hold a first material or a second material and having a cooling function to perform cryo-processing.

[0048] In some embodiments of this application, the chuck includes a coil inside which a cooling medium circulates.

[0049] In some embodiments of this application, the activation device includes a wet treatment device and a drying device.

[0050] In some embodiments of this application, the wet treatment apparatus includes a spraying device and / or a soaking device.

[0051] In some embodiments of this application, the drying device includes a spin-drying device and / or a purging device.

[0052] In some embodiments of this application, the activation device is disposed in a separate activation chamber, and / or the activation device is disposed in at least one of the transfer chamber, the cryo-activation chamber, or the bonding chamber.

[0053] In some embodiments of this application, the bonding apparatus further includes a storage chamber connected to the transmission chamber for storing the bonding structure.

[0054] In some embodiments of this application, at least one of the transfer chamber, film-forming chamber, cryogenic activation chamber, activation chamber, bonding chamber, or storage chamber is provided with a vacuum device or connected to a gas supply device to provide a low vacuum, atmospheric atmosphere, or other atmosphere suitable for process and equipment operation.

[0055] It should be noted that, due to space limitations and to avoid redundancy, this application does not exhaustively list all point values ​​within the above numerical range, but it is not limited to the listed values ​​either; other unlisted values ​​within the above numerical range are also applicable.

[0056] Compared with existing technical solutions, this application has at least the following beneficial effects:

[0057] In the method for preparing the bonding structure described in this application, the third material formed on the first material and / or the second material to be bonded is bonded through the third material. This is beneficial for the separately formed third material to obtain a smaller thickness, i.e., to form a thin layer. At the same time, by subjecting the third material to specific freezing (low temperature) activation treatment, heating recovery treatment and activation treatment in sequence, the damage to the third material can be reduced while enabling it to obtain sufficient interfacial bonding ability. Therefore, the preparation method can be used to prepare silicon-on-insulator structures with thin insulating isolation layers and no leakage current. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the bonding device provided in Embodiment 1.

[0059] Figure 2 This is a schematic flowchart of the method for preparing the bonding structure provided in Example 2.

[0060] In the figure: 1-first material, 2-second material, 3-third material, 10-transfer chamber, 11-robotic arm, 20-forming membrane chamber, 30-freeze-activation chamber, 40-activation chamber, 50-bonding chamber, 60-storage chamber. Detailed Implementation

[0061] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the application and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present application, not the entire structure.

[0062] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0063] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0064] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0065] Example 1

[0066] This embodiment provides a bonding device, such as Figure 1 As shown, the bonding apparatus includes:

[0067] A transfer chamber 10 is provided, and a robotic arm 11 is installed in the transfer chamber 10 for transferring materials;

[0068] A film-forming chamber 20 is provided, which is equipped with a sputtering deposition device, a chemical vapor deposition device, or an atomic layer deposition device, for forming a third material on a first material and / or a second material, and the film-forming chamber 20 is connected to the transfer chamber 10; (the thermal oxidation device is generally a separate furnace tube and is usually not directly incorporated into the structure of the bonding device; if oxidation film formation is involved, the original material with an oxide film can be directly provided).

[0069] The cryogenic activation chamber 30 is equipped with a plasma excitation device and a chuck. The chuck is used to hold the first material or the second material. The chuck is equipped with a coil with a circulating cooling medium, which enables the chuck to cool down for cryogenic treatment. The plasma excited by the plasma excitation device is used to activate the first material and the second material. The cryogenic activation chamber 30 is connected to the transfer chamber 10.

[0070] The activation chamber 40 is equipped with an activation device, which includes a wet treatment device and a drying device; the wet treatment device is a spray device and the drying device is a spin-drying device; and the activation chamber 40 is connected to the transfer chamber 10.

[0071] The bonding chamber 50 is used to perform bonding processing on the first material and the second material to obtain a bonding structure, and the bonding chamber 50 is connected to the transfer chamber 10.

[0072] Storage chamber 60 is connected to transmission chamber 10 and is used to store bonding structures.

[0073] This embodiment also provides a method for preparing the bonding structure, which is carried out in the bonding apparatus provided above, such as... Figure 2 As shown, the preparation method includes:

[0074] The first material 1 and the second material 2 to be bonded are both silicon materials;

[0075] The first material 1 and the second material 2 are fed into the film forming chamber 20 through the transfer chamber 10. A 1 nm silicon oxide layer is deposited on the silicon surface of the first material 1 as the third material 3 by an atomic layer deposition device. At the same time, a 1 nm silicon oxide layer is deposited on the silicon surface of the second material 2 as the third material 3.

[0076] The first material 1 and the second material 2, on which the third material 3 is disposed, are transferred through the transfer chamber 10 to the cryogenic activation chamber 30 and fixed on their respective chucks. The chuck that fixes the first material 1 freezes the first material 1 on which the third material 3 is disposed, bringing the temperature to -200°C, while the chuck that fixes the second material 2 is at room temperature (25°C). Then, plasma is used to activate one side of the bonding surface (i.e., the third material) of the first material 1 and the second material 2 on which the third material 3 is disposed. The vacuum degree of the activation process is 60 Pa, the plasma activation power is 80 W, the activation time is 70 s, and the working gas is argon.

[0077] After activation, the first material 1 and the second material 2, which are provided with the third material 3, are transferred to the activation chamber 40 through the transfer chamber 10. After the temperature of the first material 1 and the second material 2, which are provided with the third material 3, is raised to room temperature of 25°C, a spray device is used to wet treat one side of the bonding surface (i.e., the third material) of the first material 1 and the second material 2, which are provided with the third material 3. The treatment agent used for wet treatment is deionized water, i.e., water washing to carry out activation treatment. After water washing, the material is spun dry by a spin-drying device.

[0078] After spin drying, the first material 1 and the second material 2, on which the third material 3 is disposed, are transferred to the bonding chamber 40 through the transfer chamber 10. The bonding process includes pre-bonding, in which a pressure of 1N is applied to the center to make the third material 3 on the first material 1 and the third material 3 on the second material 2 come into contact and adhere. Then, the bonding process is annealed at 120°C for 1.5 hours to obtain a bonding structure, which is a silicon-on-insulator structure.

[0079] Example 2

[0080] This embodiment provides a method for preparing a bonding structure, which is carried out in the bonding apparatus described in Example 1, such as... Figure 2 As shown, the preparation method includes:

[0081] The first material 1 and the second material 2 to be bonded are both silicon materials;

[0082] The first material 1 and the second material 2 are fed into the film forming chamber 20 through the transfer chamber 10. A 2nm silicon oxide layer is sputtered on the silicon surface of the first material 1 as the third material 3 by a sputtering coating device. At the same time, a 2nm silicon oxide layer is sputtered on the silicon surface of the second material 2 as the third material 3.

[0083] The first material 1 and the second material 2, on which the third material 3 is disposed, are transferred through the transfer chamber 10 to the cryogenic activation chamber 30 and fixed on their respective chucks. The first material 1 and the second material 2, on which the third material 3 is disposed, are cryogenically treated by the chucks to a temperature of -200℃. Then, the bonding surface of the first material 1 and the second material 2 on which the third material 3 is disposed is activated by plasma. The vacuum degree of the activation treatment is 100Pa, the plasma activation power is 120W, the activation time is 36s, and the working gas is argon.

[0084] After activation, the first material 1 and the second material 2, on which the third material 3 is disposed, are transferred to the activation chamber 40 through the transfer chamber 10. The atmosphere in the activation chamber 40 is set to atmospheric atmosphere with a dew point temperature of 10°C. After the temperature of the first material 1 and the second material 2, on which the third material 3 is disposed, is raised to room temperature of 25°C, a spray device is used to wet treat one side of the bonding surface (i.e., the third material) of the first material 1 and the second material 2, on which the third material 3 is disposed, and the treatment agent used for wet treatment is deionized water, i.e., water washing to implement activation treatment. After water washing, the material is spun dry by a spin-drying device.

[0085] After spin drying, the first material 1 and the second material 2, on which the third material 3 is disposed, are transferred to the bonding chamber 50 through the transfer chamber 10. The atmosphere in the bonding chamber 50 is set to atmospheric atmosphere with a dew point temperature of 10°C. The bonding process includes pre-bonding by applying a pressure of 1N at the center to make the third material 3 on the first material 1 and the third material 3 on the second material 2 come into contact and adhere. Then, the bonding process is annealed at 120°C for 1.5 hours to obtain a bonding structure, which is a silicon-on-insulator structure.

[0086] Example 3

[0087] The difference between this embodiment and embodiment 2 is that the thickness of the third material 3 on the first material 1 is adjusted from 2nm to 4nm, and the third material 3 is not set on the second material 2. At the same time, the chuck of the second material 2 is not subjected to freezing treatment, and its temperature is set to room temperature of 25°C, that is, the second material 2 is activated at 25°C. Apart from the above, the other conditions are exactly the same as those in embodiment 2.

[0088] Example 4

[0089] The difference between this embodiment and embodiment 2 is that the third material 3 on the first material 1 and the third material 3 on the second material 2 are both changed from a sputtered silicon oxide layer to a sputtered AlN layer, and the thickness remains unchanged at 2nm. Apart from the above, the other conditions are exactly the same as in embodiment 2.

[0090] Example 5

[0091] The difference between this embodiment and embodiment 2 is that the third material 3 on the first material 1 and the third material 3 on the second material 2 are both silicon oxide layers formed by thermal oxidation device, so that the thickness of the silicon oxide layer is 2nm. Then it is sent into the transfer chamber 10 and transferred to the freeze-activation chamber 30 without entering the film-forming chamber 20. At the same time, the freezing temperature is adjusted from -200℃ to -150℃. Except for the above, the other conditions are exactly the same as those in embodiment 2.

[0092] Example 6

[0093] The difference between this embodiment and embodiment 5 is that the third material 3 on the first material 1 is a silicon oxide layer formed by a thermal oxidation device, with a thickness of 2nm. The second material 2 is not provided with the third material 3. It is then sent into the transfer chamber 10 and transferred to the freeze-activation chamber 30 without entering the film-forming chamber 20. At the same time, the freezing temperature of the first material 1 is adjusted from -150℃ to -100℃. Meanwhile, the chuck of the second material 2 is not subjected to freezing treatment and its temperature is set to room temperature of 25℃. That is, the second material 2 is activated at 25℃. Except for the above, the other conditions are exactly the same as those in embodiment 5.

[0094] Comparative Example 1

[0095] The difference between this comparative example and Example 2 is that no freezing treatment is performed before the activation treatment. That is, the corresponding chucks of the first material 1 and the second material 2 are not frozen. The initial temperature is room temperature of 25°C. That is, the first material 1 and the second material 2 are activated at 25°C. The temperature rises naturally during the activation process without interfering with the temperature. Except for the above, the other conditions are exactly the same as those in Example 2.

[0096] Comparative Example 2

[0097] The difference between this comparative example and Example 2 is that, after activation treatment, the first material 1 and the second material 2, which are provided with the third material 3, are transferred to the activation chamber 40 through the transfer chamber 10. The temperature of the first material 1 and the second material 2, which are provided with the third material 3, is raised to 2°C and then activated. They are then transferred to the bonding chamber 50 for bonding treatment. Except for the above, the other conditions are exactly the same as in Example 2.

[0098] Comparative Example 3

[0099] The difference between this comparative example and Example 2 is that, after the activation treatment, no activation treatment is performed. That is, the first material 1 and the second material 2, which are provided with the third material 3, are directly transferred to the bonding chamber 50 through the transfer chamber 10. When the temperature of the first material 1 and the second material 2, which are provided with the third material 3, is raised to 25°C, the bonding treatment is performed. Except for the above, the other conditions are exactly the same as those in Example 2.

[0100] Characterization and Testing

[0101] The following tests were performed on the bonding structures (silicon-on-insulator structures) obtained in the examples and comparative examples:

[0102] 1) Bond strength: Bond strength testing employs the blade insertion crack propagation method, which assesses bond strength by quantifying the energy threshold of interface crack propagation. The specific testing procedure is as follows: a micron-precision blade (thickness tb) is slowly inserted along the normal direction of the bonding interface to induce a controllable crack. The crack propagation length L is observed under a microscope, and the bonding surface energy γ (unit: J / m²) is calculated based on material mechanical parameters. 2 ).

[0103] 2) Leakage current: Upper and lower electrodes are fabricated on the top and bottom silicon layers, and a 10V voltage is applied between the upper and lower electrodes. Since the third material is an insulating material, and the top and bottom silicon layers are low-resistivity materials, the measured leakage current is mainly determined by the insulating properties of the third material.

[0104] 3) Heat dissipation: The bonding structure is placed on a stainless steel base, and water cooling is applied below the stainless steel base. A 1W / cm² heat dissipation layer is applied above the top silicon layer. 2 The heating power is measured by placing thermocouples on the surface to measure the surface temperature.

[0105] The test results are shown in Table 1.

[0106] Table 1

[0107]

[0108] As shown in Table 1, oxide-to-oxide bonding exhibits higher strength compared to oxide-to-silicon bonding. Increasing the oxide layer thickness reduces leakage current. Lowering the freeze-activation temperature also reduces leakage current. Due to the thin oxide layer, the surface temperature difference between different samples is smaller.

[0109] The preferred embodiments of this application have been described in detail above. However, this application is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solution of this application, and these simple modifications all fall within the protection scope of this application.

[0110] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this application will not describe the various possible combinations separately.

[0111] Furthermore, various different implementations of this application can be combined in any way, as long as they do not violate the spirit of this application, they should also be regarded as the content disclosed in this application.

Claims

1. A method for preparing a bonding structure, characterized in that, The preparation method includes: A first material and a second material to be bonded are provided; a third material is disposed on the bonding surfaces of the first material and / or the second material; both the first material and the second material comprise silicon; the third material comprises an insulating material. The first material and the second material are activated on one side of the surface to be bonded. The activation treatment includes plasma activation treatment to give the surface to be bonded hydrophilic dangling bonds or dangling groups. The activation temperature of the first material and / or the second material on which the third material is disposed is less than or equal to 0°C. The temperature of the first material and the second material is kept above the ambient dew point temperature, and an activation treatment is performed on one side of the surface to be bonded of the first material and the second material; the activation treatment method includes wet treatment with a treatment liquid containing hydrophilic molecules followed by drying, so that the surface to be bonded with dangling bonds or dangling groups adsorbs hydrophilic molecules. Then a bonding process is performed to obtain a bonding structure, which is silicon-on-insulator.

2. The method for preparing the bonding structure according to claim 1, characterized in that, The insulating material includes at least one of SiO2, SiC, SiCN, Al2O3, HfO2, AlN, or SiN.

3. The method for preparing the bonding structure according to claim 1, characterized in that, When the third material is disposed on the bonding surface of the first material and / or the second material, the total thickness of the third material is <10nm.

4. The method for preparing the bonding structure according to claim 1, characterized in that, Methods for depositing a third material on the bonding surface of the first material and / or the second material include at least one of sputtering deposition, chemical vapor deposition, atomic layer deposition, or thermal oxidation.

5. The method for preparing the bonding structure according to claim 1, characterized in that, The preparation method further includes: freezing the first material and / or the second material containing the third material before and / or during the activation treatment, so that the temperature of the first material and / or the second material containing the third material is maintained at less than or equal to 0°C.

6. The method for preparing the bonding structure according to claim 1 or 5, characterized in that, Making the temperature of the first material and the second material higher than the ambient dew point temperature includes: restoring the temperature of the first material and the second material to room temperature of 15°C to 35°C.

7. The method for preparing the bonding structure according to claim 1, characterized in that, The wet treatment solution includes at least one of water, formic acid, or ethanol. And / or, the wet treatment method includes spraying and / or soaking; And / or, the drying method includes spin drying and / or purging.

8. The method for preparing the bonding structure according to claim 1, characterized in that, The vacuum degree of the activation treatment is 0.1 Pa to 200 Pa; And / or, the vacuum degree of the bonding process is 0.05 Pa to 200 Pa.

9. The method for preparing the bonding structure according to claim 1, characterized in that, The preparation method further includes: after the bonding treatment, performing an annealing treatment to obtain the bonding structure.

10. The method for preparing the bonding structure according to claim 9, characterized in that, The bonding process includes pre-bonding at 15℃~35℃ and applying pressure of 0.1N~500N; And / or, the annealing treatment is performed at a temperature of 100℃ to 450℃ for a time of 1h to 24h.

11. A bonding structure, characterized in that, The bonding structure is obtained by the preparation method according to any one of claims 1-10; the bonding structure comprises a first material, a third material, and a second material stacked together.

12. The bonding structure according to claim 11, characterized in that, The bonding structure satisfies at least one of the following conditions: (1a) Both the first material and the second material comprise silicon; (1b) The third material includes an insulating material, which includes at least one of SiO2, SiC, SiCN, Al2O3, HfO2, AlN or SiN; (1c) The total thickness of the third material is <10 nm.

13. A bonding device, characterized in that, For implementing the preparation method according to any one of claims 1-10, or for preparing the bonding structure according to claim 11 or 12, the bonding device includes a transfer chamber and further includes: A freeze-activation chamber is configured to freeze a first material and / or a second material on which a third material is disposed, and to activate the first material and the second material, and is connected to the transfer chamber. An activation device configured to activate the first material and the second material; A bonding chamber is configured to perform bonding processing on the first material and the second material to obtain a bonding structure, and is connected to the transport chamber.

14. The bonding apparatus according to claim 13, characterized in that, The bonding device satisfies at least one of the following conditions: (2a) The transfer chamber includes a robotic arm for transferring materials; (2b) The bonding apparatus further includes a film-forming chamber, which includes at least one of a sputtering deposition apparatus, a chemical vapor deposition apparatus, or an atomic layer deposition apparatus; (2c) The cryogenic activation chamber includes a plasma excitation device and a chuck, the chuck being used to hold the first material or the second material and having a cooling function to perform cryogenic treatment; (2d) The activation device includes a wet treatment device and a drying device; (2e) The activation device is configured in a separate activation chamber; And / or, the activation device is disposed in at least one of the transfer chamber, the cryo-activation chamber, or the bonding chamber; (2f) The bonding device further includes a storage chamber connected to the transmission chamber for storing the bonding structure.

15. The bonding apparatus according to claim 14, characterized in that, The bonding device satisfies at least one of the following conditions: (3a) The chuck in the cryogenic activation chamber includes a coil, and a cooling medium circulates inside the coil; (3b) The wet treatment device in the activation device includes a spraying device and / or a soaking device; (3c) The drying device in the activation device includes a spin-drying device and / or a purging device.

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