Preparation method of semiconductor device

Abstract

The invention discloses a preparation method of a semiconductor device, and relates to the technical field of semiconductor manufacturing. The preparation method comprises the steps that a first wafer bonding piece and a second wafer bonding piece are pre-cleaned respectively, pre-cleaning comprises megasonic assisted SC1 cleaning, and supercritical CO2 drying treatment is carried out on the pre-cleaned first wafer bonding piece and the pre-cleaned second wafer bonding piece respectively to remove moisture of the first wafer bonding piece and the second wafer bonding piece; performing surface activation on the first wafer bonding sheet and the second wafer bonding sheet; and bonding and connecting the first wafer bonding sheet and the second wafer bonding sheet in a silicon-oxygen bonding mode to prepare the semiconductor device. According to the preparation method, the cleaning effect can be improved, the surface roughness can be improved, the water remaining in the hole cavity structure after cleaning can be effectively removed, and the situation that the yield of the semiconductor device is reduced due to the fact that excessive water forms steam bubbles during annealing after bonding is prevented.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor manufacturing, in particular to a preparation method of a semiconductor device. BACKGROUND

[0002] Silicon-oxygen bonding (Si-O-Si Bonding) is widely used in the manufacture of 3D chips, micro-electro-mechanical systems, silicon-on-insulator devices, etc. Bonding quality mainly depends on surface cleanliness and chemical activity. For silicon-oxygen bonding wafers with pore cavity structures, the residual moisture in the pore cavity is also an important factor affecting bonding.

[0003] In the prior art, the way to remove residual moisture in the cavity is usually RCA cleaning before bonding, that is, SPM (Sulfuric Peroxide Mixture) cleaning and SC1 (Standard Clean 1) cleaning. Among them, SPM is mainly used for cleaning of front photoresist / organic matter, and SC1 is mainly used for removing light organic matter and part of the metal. After cleaning, it is dried by spinning. Organic matter and metal ions can be effectively removed by RCA cleaning. However, conventional RCA cleaning is difficult to enter the small pore cavity structure, and the efficiency decreases for submicron (<0.1um) particles, and the cleaning effect is limited. The corrosion of NH4OH in SC1 to the oxide layer will cause micro-roughness, which may affect the bonding surface. In addition, the cleaning solution adheres to the inside of the pore cavity and cannot be effectively spun out. Excessive moisture forms water vapor bubbles during annealing after bonding. SUMMARY

[0004] One object of the present application is to provide a preparation method of a semiconductor device, which solves the technical problem of poor cleaning effect of the silicon-oxygen bonding surface and poor silicon-oxygen bonding quality caused by residual moisture in the prior art.

[0005] Another object of the present application is to significantly reduce the risk of structure collapse and interface tearing caused by capillary stress and improve the structure integrity before bonding.

[0006] According to the purpose of the present application, the present application provides a preparation method of a semiconductor device, the semiconductor device comprising a first wafer bonding wafer and a second wafer bonding wafer, the preparation method comprising: Pre-cleaning the first wafer bonding wafer and the second wafer bonding wafer respectively, the pre-cleaning comprising megasonic assisted SC1 cleaning, the volume ratio of NH4OH, H2O2 and H2O in the SC1 cleaning solution being any one of (0.3-0.5):1:5, and the frequency of the megasonic being any one of 0.5MHz-3MHz; The first wafer bonding wafer and the second wafer bonding wafer were subjected to supercritical CO2 drying treatment after pre-cleaning to remove moisture from the first wafer bonding wafer and the second wafer bonding wafer; Surface activation is performed on the first wafer bonding wafer and the second wafer bonding wafer; The first wafer bonding sheet and the second wafer bonding sheet are bonded together by silicon-oxygen bonding to prepare the semiconductor device.

[0007] Optionally, the working temperature of the supercritical CO2 drying process is any value between 40℃ and 50℃, and the working pressure is any value between 10MPa and 20MPa.

[0008] Optionally, the surface activation is performed by plasma treatment at a first preset temperature.

[0009] Optionally, the gas used for plasma treatment contains N2, O2, or Ar.

[0010] Optionally, the radio frequency power of the plasma treatment is any value between 50W and 300W.

[0011] Optionally, the temperature for the megasonic-assisted SC1 cleaning is any value between 40°C and 80°C.

[0012] Optionally, the thickness of the oxide layer formed by the silicon-oxygen bonding connection between the first wafer bonding wafer and the second wafer bonding wafer is any value between 0.5 μm and 2.0 μm.

[0013] Optionally, the pre-cleaning further includes SPM cleaning, wherein the volume ratio of H2SO4 to H2O2 in the SPM cleaning solution is any value of (2-5):1.

[0014] Optionally, the SPM cleaning temperature is any value between 100℃ and 150℃.

[0015] This invention introduces a coupled process flow of megasonic-assisted cleaning, low-corrosion ratio control, supercritical CO2 drying, and surface activation. Specifically, megasonic-assisted SC1 improves particle removal rate while controlling roughness, providing a permeable surface for supercritical CO2 drying. Supercritical CO2 drying ensures the surface is dry and anhydrous, providing a clean prerequisite for surface activation. Surface activation provides bonding active sites, laying the foundation for the final formation of Si-O-Si covalent bonds. This effectively improves cleaning depth and particle removal rate, controls surface roughness caused by cleaning, thoroughly removes moisture from pores, and constructs a highly active reaction interface. It synergistically optimizes the interface cleanliness, chemical activity, and bonding reliability between silicon-oxygen bonded sheets from multiple dimensions, preventing the cleaning solution from adhering to the inside of the pores and failing to be effectively removed, which would lead to excessive moisture forming water bubbles during post-bonding annealing.

[0016] Furthermore, the working temperature of the supercritical CO2 drying process of the present invention is any value between 40℃ and 50℃, and the working pressure is any value between 10MPa and 20MPa. By performing supercritical CO2 drying process in the supercritical state under the above working temperature and working pressure conditions, the CO2 density is close to that of a liquid, while the diffusion coefficient is closer to that of a gas, which has higher permeability and migration ability. It can effectively penetrate and replace the moisture in micropores with high aspect ratio or submicron scale. Moreover, the deep supercritical CO2 under high pressure has near-zero surface tension. Even when drying in a large curvature and narrow gap, no tensile force will be generated at the water / gas interface, which can significantly reduce the risk of structural collapse and interface tearing caused by capillary stress and improve the structural integrity before bonding.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0018] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is a schematic flowchart of a method for fabricating a semiconductor device according to an embodiment of the present invention; Figure 2 This is a C-scan acoustic micrograph of the first wafer bonding wafer according to Embodiment 1 of the present invention; Figure 3 This is a C-scan acoustic micrograph of the first wafer bonding wafer according to Comparative Example 1 of the present invention. Detailed Implementation

[0019] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0020] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0021] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] Figure 1 This is a schematic flowchart of a method for fabricating a semiconductor device according to an embodiment of the present invention.

[0024] like Figure 1 As shown, this invention provides a method for fabricating a semiconductor device. The semiconductor device includes a first wafer bonding wafer and a second wafer bonding wafer, which are bonded together by silicon-oxygen bonding. The method for fabricating the semiconductor device includes: Step S100: Pre-clean the first wafer bonding wafer and the second wafer bonding wafer respectively. The pre-cleaning includes megasonic wave-assisted SC1 cleaning. The volume ratio of NH4OH, H2O2 and H2O in the SC1 cleaning solution is any value of (0.3-0.5):1:5, and the frequency of the megasonic wave is any value of 0.5MHz-3MHz. Step S200: Perform supercritical CO2 drying on the pre-cleaned first wafer bonding wafer and the second wafer bonding wafer respectively to remove moisture from the first wafer bonding wafer and the second wafer bonding wafer; Step S300: Surface activation is performed on the first wafer bonding wafer and the second wafer bonding wafer; Step S400: The first wafer bonding sheet and the second wafer bonding sheet are bonded together by silicon-oxygen bonding to prepare a semiconductor device.

[0025] In this embodiment, in the semiconductor device fabrication method, after obtaining the first wafer bonding wafer and the second wafer bonding wafer to be bonded, firstly, the first wafer bonding wafer and the second wafer bonding wafer are pre-cleaned using megasonic wave-assisted SC1 cleaning, respectively. Then, the first wafer bonding wafer and the second wafer bonding wafer after pre-cleaning are subjected to supercritical CO2 drying treatment to remove moisture from the first wafer bonding wafer and the second wafer bonding wafer. The surfaces of the first wafer bonding wafer and the second wafer bonding wafer are then activated. Finally, the first wafer bonding wafer and the second wafer bonding wafer are bonded together by silicon-oxygen bonding to obtain the semiconductor device. Here, the volume ratio of NH4OH, H2O2, and H2O in the SC1 cleaning solution is any value within the range of (0.3-0.5):1:5, that is, the volume ratio of NH4OH, H2O2, and H2O can be 0.3:1:5, 0.35:1:5, 0.4:1:5, 0.45:1:5, or 0.5:1:5, or any other value within the range of (0.3-0.5):1:5. The frequency of the megasonic wave is any value within the range of 0.5MHz-3MHz, that is, the frequency of the megasonic wave can be 0.5MHz, 1MHz, 1.5MHz, 2MHz, 2.5MHz, or 3MHz, or any other value within the range of 0.5MHz-3MHz.

[0026] In this embodiment, a coupled process of megasonic-assisted cleaning, low-corrosion ratio control, supercritical CO2 drying, and surface activation is introduced. Specifically, megasonic-assisted SC1 improves particle removal rate while controlling roughness, providing a permeable surface for supercritical CO2 drying. Supercritical CO2 drying ensures the surface is dry and water-free, providing a clean prerequisite for surface activation. Surface activation provides bonding active sites, laying the foundation for the final formation of Si-O-Si covalent bonds. This effectively improves cleaning depth and particle removal rate, controls surface roughness caused by cleaning, thoroughly removes moisture from pores, and constructs a highly active reaction interface. Multi-dimensional synergistic optimization of the interface cleanliness, chemical activity, and bonding reliability between silicon-oxygen bonded sheets prevents cleaning solution from adhering to the inside of the pores and failing to be effectively removed, which would lead to excessive moisture forming water bubbles during post-bonding annealing.

[0027] In this embodiment, the pre-cleaning step employs megasonic-assisted SC1 cleaning. Megasonic waves with frequencies ranging from 0.5MHz to 3MHz effectively break down boundary layers through micro-cavitation, enhancing the penetration of the cleaning solution and microfluidic disturbance. This allows submicron particles (<0.1μm) to be efficiently desorbed and transferred within the deep pore structure. Simultaneously, by optimizing the NH4OH volume ratio in SC1 to 0.3-0.5, the anisotropic etching rate during the cleaning process is controlled, ensuring that the cleaned silicon or silicon oxide surface maintains an RMS (Root Mean Square) roughness below 0.5nm. This provides a more uniform contact surface for subsequent bonding. Furthermore, the synergistic effect of megasonic waves and SC1 significantly reduces the risk of surface damage while improving cleaning capabilities, achieving high-cleanliness, low-damage surface preparation.

[0028] In this embodiment, the supercritical CO2 drying step uses supercritical CO2 with a temperature higher than 31.1°C and a pressure higher than 7.38 MPa. Its low viscosity, high diffusivity and zero surface tension characteristics can fully replace the residual moisture in the micropores and structural gaps, effectively avoiding the water retention problem that cannot be removed by conventional spin drying or nitrogen blowing. This not only significantly reduces bubbles, holes or peeling defects caused by water evaporation during the wafer bonding annealing process, but also avoids the inhibition of interfacial reaction activity by water vapor, thus improving the controllability and consistency of the interfacial reaction.

[0029] In this embodiment, the surface dried by supercritical CO2 possesses the prerequisite of high cleanliness and absence of water residue. The surface activation step can further increase the density of silanol groups on the surface of the first or second wafer bonding sheet, enabling them to rapidly transform into a Si-O-Si covalent network structure through dehydration condensation reaction during subsequent bonding, thereby enhancing interfacial bonding strength, increasing bonding rate, and improving thermal stability. Furthermore, the surface activation treatment step and the pre-cleaning step form a virtuous cycle, preventing the silanol groups from being contaminated or shielded after activation, ensuring that they maintain high activity before bonding.

[0030] In a further embodiment, the working temperature of the supercritical CO2 drying process is any value between 40℃ and 50℃, and the working pressure is any value between 10MPa and 20MPa. That is, the working temperature of the supercritical CO2 drying process can be 40℃, 41℃, 42℃, 43℃, 44℃, 45℃, 46℃, 47℃, 48℃, 49℃ or 50℃, or any other value between 40℃ and 50℃, and the working pressure can be 10MPa, 11MPa, 12MPa, 13MPa, 14MPa, 15MPa, 16MPa, 17MPa, 18MPa, 19MPa or 20MPa, or any other value between 10MPa and 20MPa. In this embodiment, supercritical CO2 drying is performed in a supercritical state under the above-mentioned working temperature and pressure conditions. At this time, the CO2 density is close to that of a liquid, while the diffusion coefficient is closer to that of a gas, which has higher permeability and migration ability. It can effectively penetrate and replace the water in micropores with high aspect ratio or submicron scale. Furthermore, the deep supercritical CO2 under high pressure has near-zero surface tension. Even when drying in a large curvature and narrow gap, it will not generate tensile force at the water / gas interface, which can significantly reduce the risk of structural collapse and interface tearing caused by capillary stress and improve the structural integrity before bonding.

[0031] In this embodiment, during the supercritical CO2 drying process, increasing the working temperature and working pressure can significantly improve the critical solubility of CO2 and the rate of moisture carrying, making the moisture transfer from the structure more efficient. This is beneficial for completing the drying process in a shorter time, increasing the process throughput, reducing heat exposure time, improving the drying rate, and shortening the overall process time.

[0032] In a further embodiment, surface activation is performed by plasma treatment at a first preset temperature. In this embodiment, plasma surface activation at the first preset temperature effectively increases the surface hydroxyl density, enhances the driving force of the Si-O-Si covalent bonding reaction, and simultaneously suppresses surface damage, promotes water decomposition and adsorption, and improves treatment uniformity. This further optimizes the chemical activity and stability of the bonding interface, providing better interface conditions for high-quality bonding. Here, the surface activation method can also be any one of wet chemical treatment, surface functionalization, or ion beam activation.

[0033] In a further embodiment, the plasma treatment gas includes N2, O2, or Ar. In this embodiment, using any one of N2, O2, or Ar as the plasma treatment medium allows for flexible selection of the activation mechanism based on device structure and material requirements, enhancing surface hydroxyl density and improving hydrophilicity, thus providing multidimensional support for high-yield silicon-oxygen bonding. Here, the gas can also be an O2 / N2 mixture or an O2 / Ar mixture.

[0034] In this embodiment, different degrees of cleaning, activation and microstructure control can be achieved by selecting different gases during plasma treatment. Furthermore, the appropriate selection of treatment gases can achieve a lower RMS roughness without damaging the surface, thereby improving the uniformity and stability of subsequent bonding and reducing the probability of voids, bubbles and delamination defects.

[0035] In this embodiment, when the gas used for plasma treatment is N2, the N2 plasma can generate amino groups (-NH2) or nitrogen oxides (Si-N) on the surface. x O y The functional groups enhance surface polarity and hydrophilicity, providing a mild and uniform activation effect on the silicon substrate surface. This is suitable for increasing surface energy without introducing additional oxidative damage, which helps to improve the initial adhesion strength of the bond and the rate of subsequent dehydration condensation reaction.

[0036] In this embodiment, when the gas used for plasma treatment is O2, the strong oxidizing property of O2 plasma can significantly enhance the surface hydroxyl density, promote the formation of high-concentration Si-OH functional groups, and simultaneously remove organic residues, thereby improving the cleanliness of the interface.

[0037] In this embodiment, when the gas used for plasma treatment is Ar, Ar is an inert gas that does not undergo chemical reactions, but it can produce physical removal and surface activation effects through kinetic energy bombardment. Ar plasma can slightly etch the surface, remove weak bonded compounds or contaminant layers, and at the same time induce the formation of surface dangling bonds, thereby improving surface reactivity.

[0038] In a further embodiment, the radio frequency (RF) power of the plasma treatment is any value between 50W and 300W. That is, the RF power of the plasma treatment can be 50W, 100W, 150W, 200W, 250W, or 300W, or any other value between 50W and 300W. In this embodiment, the RF power determines the density and energy of the active particles in the plasma, thereby affecting the intensity of their interaction with the wafer surface. When the RF power is between 50W and 100W, it is suitable for treating materials with weak thin-film structures and sensitive to surface damage, such as ultrathin SiO2 and hydrophobic modified films, which can gently introduce Si-OH functional groups while ensuring the integrity of the material. When the RF power is between 150W and 200W, a good balance is achieved between increasing the surface functional group density and cleanliness, which is suitable for conventional Si / SiO2 bonding systems. When the RF power is between 250W and 300W, it is suitable for interface treatment with heavy contamination or requiring deep activation, which can quickly generate high-density hydroxyl groups or remove residual organic matter, thereby improving bonding activity. In other words, this embodiment can flexibly adjust the radio frequency energy density according to the material characteristics, contamination level and interface activation requirements, thereby achieving a balance between increasing hydroxyl density, enhancing bonding activity, controlling surface roughness and damage risk, improving the consistency of the bonding interface and high-quality bonding effect, while having good process adaptability and batch manufacturing stability.

[0039] In a further embodiment, the temperature for megasonic-assisted SC1 cleaning is any value between 40℃ and 80℃. Specifically, the temperature can be 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, or 80℃, or any other value within the 40℃-80℃ range. In this embodiment, the temperature for megasonic-assisted SC1 cleaning is set within the 40℃-80℃ range, allowing for flexible adjustment based on different wafer surface contamination types, structural complexity, and material sensitivity. Increasing the temperature not only enhances the cleaning activity and cavitation efficiency of the SC1 solution, improving the removal of submicron particles and organic impurities, but also helps improve the fluidity and permeability of the solution within the porous structure, thereby increasing the cleaning uniformity within the structure. Simultaneously, through the synergistic effect of temperature control and megasonic waves, an optimal balance is achieved between cleaning efficiency, surface protection, and porous compatibility.

[0040] In a further embodiment, the thickness of the oxide layer formed by the silicon-oxygen bonding connection of the first and second wafer bonding wafers is any value between 0.5 μm and 2.0 μm. The thickness of the oxide layer can be 0.5 μm, 1.0 μm, 1.5 μm, or 2.0 μm, or any other value within the range of 0.5 μm to 2.0 μm. In this embodiment, controlling the thickness of the oxide layer formed by the silicon-oxygen bonding connection of the first and second wafer bonding wafers between 0.5 μm and 2.0 μm ensures sufficient hydroxyl activity on the oxide layer surface to achieve stable Si-O-Si bonding, while also reducing interfacial thermal stress and strain gradient, thus reducing the generation of micro-defects. Simultaneously, this thickness range is highly adaptable, compatible with various subsequent process flows, and improves the electrical stability and mechanical integrity of the bonding interface, thereby improving the yield and reliability of the final semiconductor device.

[0041] In a further embodiment, the pre-cleaning also includes SPM cleaning, wherein the volume ratio of H2SO4 to H2O2 in the SPM cleaning solution is any value within the range of (2-5):1. That is, the volume ratio of H2SO4 to H2O2 in the cleaning solution can be 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, or 5:1, or any other value within the range of (2-5):1. In this embodiment, controlling the volume ratio of H2SO4 to H2O2 in the SPM cleaning solution within the range of (2-5):1 helps to improve the removal ability of organic contaminants and photoresist residues on the wafer surface, achieving efficient, gentle, and controllable chemical oxidation cleaning.

[0042] In a further embodiment, the SPM cleaning temperature is any value between 100℃ and 150℃, meaning the SPM cleaning temperature can be 100℃, 110℃, 120℃, 130℃, 140℃, or 150℃, or any other value within the 100℃-150℃ range. In this embodiment, setting the SPM cleaning temperature to any value between 100℃ and 150℃ significantly enhances the oxidation decomposition efficiency and improves the penetration and diffusion of the cleaning solution, thereby effectively removing stubborn organic matter and photoresist residues from the wafer surface. This is particularly suitable for silicon-oxygen bonded wafers with complex structures and abundant cavities. Simultaneously, this temperature range facilitates the adjustment of the cleaning rate and process window, achieving efficient control of surface contamination before bonding, and providing cleaner and more uniform interface conditions for subsequent SCI cleaning, supercritical drying, and Si-O-Si bonding.

[0043] The technical solution of this application will be further described below with reference to specific embodiments.

[0044] In some embodiments, in the method for fabricating a semiconductor device, after obtaining a first wafer bonding wafer and a second wafer bonding wafer to be bonded, the first wafer bonding wafer and the second wafer bonding wafer are first pre-cleaned using megasonic-assisted SC1 cleaning, and the pre-cleaned first wafer bonding wafer and the second wafer bonding wafer are respectively subjected to supercritical CO2 drying treatment to remove moisture from the first wafer bonding wafer and the second wafer bonding wafer. The surfaces of the first wafer bonding wafer and the second wafer bonding wafer are then activated, and the first wafer bonding wafer and the second wafer bonding wafer are bonded together by silicon-oxygen bonding to obtain a semiconductor device. The volume ratio of NH4OH, H2O2, and H2O in the SC1 cleaning solution is any value between (0.3-0.5):1:5; the frequency of the megasonic wave is any value between 0.5MHz and 3MHz; the working temperature of the supercritical CO2 drying treatment is any value between 40℃ and 50℃; the working pressure is any value between 10MPa and 20MPa; and the gas used for plasma treatment is any one of N2, O2, and Ar.

[0045] Example 1 First, the first and second wafer bonding wafers were pre-cleaned using megasonic-assisted SC1 cleaning. Then, the pre-cleaned wafers were subjected to supercritical CO2 drying to remove moisture, followed by surface activation. Finally, the wafers were bonded together via silicon-oxygen bonding to fabricate a semiconductor device. The volume ratio of NH4OH, H2O2, and H2O in the SC1 cleaning solution was any value within the range of 0.4:1:5. The megasonic frequency was 1 MHz, the supercritical CO2 drying temperature was 40 °C, the operating pressure was 15 MPa, and the plasma treatment gas was N2.

[0046] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that supercritical CO2 drying was not performed after pre-cleaning.

[0047] To verify the effectiveness of supercritical drying in removing moisture during bonding, C-scan acoustic microscopy was performed on the semiconductor devices prepared in Example 1 and Comparative Example 1, yielding the following results: Figure 2 and Figure 3 The microscopic image shown.

[0048] Figure 2 This is a C-scan acoustic micrograph of the first wafer bonding wafer according to Embodiment 1 of the present invention. Figure 3 This is a C-scan acoustic micrograph of the first wafer bonding wafer according to Comparative Example 1 of the present invention.

[0049] like Figure 2 andFigure 3 As shown, after annealing, the bonded sheet (Example 1) that underwent supercritical drying exhibited better bonding surface performance, while the bonded sheet that was not dried (Comparative Example 1) showed more bonding voids at its edges. The results indicate that pre-cleaning combined with supercritical CO2 drying and surface activation can achieve an ultra-clean surface, improve surface roughness, and effectively remove cleaning fluid adhering to the pores, preventing excessive moisture from forming water bubbles during post-bonding annealing.

[0050] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0051] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method of manufacturing a semiconductor device, characterized by, The semiconductor device comprises a first wafer key sheet and a second wafer key sheet, and the preparation method comprises: Pre-cleaning the first wafer key sheet and the second wafer key sheet respectively, wherein the pre-cleaning comprises megasonic assisted SC1 cleaning, the volume ratio of NH4OH, H2O2 and H2O in the SC1 cleaning solution is any value in (0.3-0.5):1:5, and the frequency of the megasonic wave is any value in 0.5MHz-3MHz; Supercritical CO2 drying treatment is performed on the pre-cleaned first wafer key sheet and the second wafer key sheet respectively to remove the moisture of the first wafer key sheet and the second wafer key sheet; Surface activation is performed on the first wafer key sheet and the second wafer key sheet; The first wafer key sheet and the second wafer key sheet are bonded and connected by silicon-oxygen bonding to obtain the semiconductor device.

2. The preparation method of claim 1, wherein, the working temperature of the supercritical CO2 drying treatment is any value in 40℃-50℃, and the working pressure is any value in 10MPa-20MPa.

3. The preparation method of claim 1, wherein, the surface activation is plasma treatment at a first preset temperature.

4. The preparation method of claim 3, wherein, the gas of the plasma treatment comprises N2, O2 or Ar.

5. The preparation method of claim 4, wherein, the radio frequency power of the plasma treatment is any value in 50W-300W.

6. The preparation method of claim 1, wherein, the temperature of the megasonic assisted SC1 cleaning is any value in 40℃-80℃.

7. The preparation method of any one of claims 1-6, wherein, the thickness of the oxide layer formed by the silicon-oxygen bonding connection of the first wafer key sheet and the second wafer key sheet is any value in 0.5μm-2.0μm.

8. The preparation method according to claim 7, characterized in that, The pre-cleaning further comprises SPM cleaning, and the volume ratio of H2SO4 and H2O2 in the cleaning solution of the SPM cleaning is any value in (2-5):

1.

9. The preparation method of claim 8, wherein, the temperature of the SPM cleaning is any value in 100℃-150℃.

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