Wafer bonding device and method based on a composite aluminum oxide interlayer

Abstract

The application relates to a wafer bonding device and method based on a composite alumina intermediate layer, and belongs to the technical field of semiconductors. The device comprises a first wafer, a second wafer, and a precursor ozone-assisted growth alumina layer, a precursor water-assisted growth alumina layer, a precursor water-assisted growth alumina layer and a precursor ozone-assisted growth alumina layer arranged in sequence from the first wafer to the second wafer and located between the first wafer and the second wafer, and the two precursor water-assisted growth alumina layers are bonded. The device can effectively inhibit the generation of H2O bubbles at the interface.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor, in particular to a wafer bonding device and method based on composite aluminum oxide intermediate layer. BACKGROUND

[0002] With the increasing demand for electronic devices such as mobile terminals, wearable electronic devices and data communication, the performance requirements are also increasing, and the research on semiconductor technology has become more and more important.

[0003] Wafer is the basic material of the whole semiconductor technology, and wafer bonding can effectively realize new structure, and efficiently and low-cost manufacture of heterogeneous integration of materials / devices, therefore, wafer bonding has become an indispensable key technology in the field of semiconductor. The traditional silicon fusion bonding and plasma bonding method are based on the hydroxyl polymerization of the surface of hydrophilic material, and generally need high-temperature annealing of 200-1000℃ to obtain high bonding strength, but the hydroxyl polymerization and high-temperature annealing can cause thermal stress, thermal damage and interface hole, etc. problems, especially for new compound semiconductor materials or other special application occasions.

[0004] When the bonded wafers need to meet the requirements of temporary bonding or self-stopping process in the subsequent process, a bonding auxiliary layer is usually inserted between the two wafer pieces to achieve the effect of physical isolation or self-stopping. The bonding auxiliary layer can be selected from materials such as silicon oxide and aluminum oxide. Because the bonding energy of aluminum oxide material is stronger, the thermal conductivity is moderate, it has the ability to adsorb water molecules at the interface, and it has strong light transmission, so it has broad development prospects in the fields of light and electricity. In some high-temperature compatible process requirements, aluminum oxide medium will be preferred.

[0005] The traditional wafer bonding is to grow aluminum oxide on the surface of two wafers by using precursor water assistance, and then bond the two wafers, which has more bubbles at the bonding interface after bonding. SUMMARY

[0006] In view of the above analysis, the embodiments of the present application aim to provide a wafer bonding device and method based on composite aluminum oxide intermediate layer to solve the problem of many bubbles in the existing wafer bonding by water precursor assisted growth of aluminum oxide.

[0007] In one aspect, the present application provides a wafer bonding device based on composite aluminum oxide intermediate layer, which comprises a first wafer, a second wafer, and a precursor ozone assisted growth of aluminum oxide layer, a precursor water assisted growth of aluminum oxide layer, a precursor water assisted growth of aluminum oxide layer and a precursor ozone assisted growth of aluminum oxide layer arranged in turn and stacked between the first wafer and the second wafer, and the two precursor water assisted growth of aluminum oxide layers are bonded and connected.

[0008] Preferably, in step A, the thickness of the precursor ozone-assisted grown aluminum oxide layer is greater than 2nm.

[0009] Preferably, in step A, the thickness of the precursor water-assisted grown aluminum oxide layer is no more than 2nm.

[0010] In another aspect, the present application provides a wafer bonding method based on a composite aluminum oxide intermediate layer, a precursor water-assisted grown aluminum oxide layer is a wafer bonding layer, and a precursor ozone-assisted grown aluminum oxide layer is arranged on the opposite side of the bonding side of the precursor water-assisted grown aluminum oxide layer.

[0011] Preferably, the method comprises the following steps:

[0012] Step A: forming a composite aluminum oxide layer on the surface of the first wafer and the second wafer respectively, the composite aluminum oxide layer comprises a precursor ozone-assisted grown aluminum oxide layer and a precursor water-assisted grown aluminum oxide layer stacked in turn from the surface of the first wafer upwards;

[0013] Step B: performing surface activation treatment on the first wafer and the second wafer containing the composite aluminum oxide layer;

[0014] Step C: placing the composite aluminum oxide layers of the first wafer and the second wafer in contact with each other and performing bonding treatment.

[0015] Preferably, in step A, the method for forming the composite aluminum oxide layer is ALD deposition method.

[0016] Preferably, in step A, the growth temperature of the precursor ozone-assisted grown aluminum oxide layer and the precursor water-assisted grown aluminum oxide layer is less than 350℃.

[0017] Preferably, in step B, the surface activation treatment is plasma activation treatment method, and the temperature of the surface activation treatment is 16-26℃.

[0018] Preferably, in step C, the bonding treatment is performed in a vacuum chamber, and the pressure of the vacuum chamber is 10 -7 -10 -10 Pa.

[0019] Preferably, in step C, the bonding pressure of the bonding treatment is 100-1000kg, and the bonding temperature is 16-26℃.

[0020] In a third aspect, the present application also provides a device comprising a wafer prepared according to the above method.

[0021] Compared with the prior art, the present application can at least achieve one of the following beneficial effects:

[0022] 1. In the wafer bonding device and method of the present application, the precursor ozone-assisted growth of the aluminum oxide layer is used, which is mainly composed of O ions, and only a small amount of O-H bonds, which are H2O groups formed at the interface during the bonding of the precursor water-assisted growth of the aluminum oxide layer and the subsequent high-temperature process (such as the subsequent alloying process, high-temperature material growth process, interface reinforcement process, etc. of the bonded wafer device, which generally has a temperature of 600-1700°C), and the interface residual O-H bonds, H bonds and H2O groups provide an effective diffusion channel, avoiding the formation of H2O at the interface and the formation of H2O bubbles in the aluminum oxide material.

[0023] 2. The use of precursor ozone-assisted growth of the aluminum oxide layer effectively suppresses the formation of H2O bubbles at the interface and the formation of H2O bubbles in the aluminum oxide material, so that the wafer bonding device has fewer bubbles, higher bonding rate, and the bonding effective area can reach 98%.

[0024] 3. The device and method of the present application can make the bonding strength between the wafers reach or even exceed the silicon body strength (2.5 J / m 2 ), and can withstand most of the subsequent process processing.

[0025] 4. Since the bonding method of the present application uses an intermediate layer of aluminum oxide, the method can bond any two substrates and devices.

[0026] 5. In one embodiment, the bonding temperature of the present application is 16-26°C, which is a room temperature bonding technology, avoiding any damage and destruction caused by heat, and is also suitable for wafers that have been structurally treated.

[0027] In the present application, the above technical solutions can be combined with each other to realize more preferred combination schemes. Other features and advantages of the present application will be described in the subsequent specification, and some advantages will become apparent from the specification, or will be understood by implementing the present application. The purpose and other advantages of the present application can be achieved and obtained from the contents specifically pointed out in the specification and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0028] The accompanying drawings are included to provide a further understanding of the application and are incorporated herein and constitute a part of the application. The drawings illustrate embodiments of the application and, together with the description, serve to explain the principles of the application. In the drawings:

[0029] Figure 1 Flow chart of the wafer bonding method of the present application based on the composite aluminum oxide intermediate layer;

[0030] Figure 2 Structure diagram of the composite aluminum oxide layer on the first wafer;

[0031] Figure 3 A process flow chart before the bonding step of the present application, wherein Fig. (a) is a step flow chart, and Fig. (b) is a structural effect schematic diagram corresponding to the step shown in Fig. (a);

[0032] Figure 4 A structural schematic diagram of the wafer bonded device of the present application;

[0033] Figure 5 An ultrasonic scan of the wafer bonded device obtained in Example 2;

[0034] Figure 6 An ultrasonic scan of the wafer bonded device obtained in Comparative Example 1.

[0035] Reference signs:

[0036] 1 - first wafer; 2 - second wafer; 3 - composite alumina layer; 301 - precursor ozone-assisted growth alumina layer; 302 - precursor water-assisted growth alumina layer. DETAILED DESCRIPTION

[0037] The preferred embodiments of the present application will be described in detail below with reference to the accompanying drawings, which form a part of this application. The accompanying drawings, together with the description, are used to explain the principles of the present application and are not intended to limit the scope of the present application.

[0038] In the conventional wafer bonding, water precursor-assisted growth alumina is respectively formed on the surfaces of two wafers, and then the two wafers are bonded. In this method, on the one hand, when the water precursor-assisted growth alumina layers on the surfaces of the two wafers are bonded, the interface OH groups combine with each other to generate H2O groups at the interface. Due to the high OH concentration in the water precursor-assisted growth alumina layer, the H2O groups at the interface cannot quickly diffuse, thereby causing aggregation and finally forming H2O bubbles at the interface; on the other hand, a large number of OH groups exist in the water precursor-assisted growth alumina, which are easy to combine to form H2O under subsequent high temperature and difficult to be discharged in the thick alumina, thereby forming H2O bubbles in the alumina body.

[0039] Based on this, the present application provides a wafer bonded device based on a composite alumina intermediate layer, which comprises a first wafer, a second wafer, and a precursor ozone-assisted growth alumina layer, a precursor water-assisted growth alumina layer, a precursor water-assisted growth alumina layer and a precursor ozone-assisted growth alumina layer arranged in turn and stacked between the first wafer and the second wafer, and the two precursor water-assisted growth alumina layers are bonded and connected.

[0040] Compared with the prior art, in the wafer bonding device of the application, the higher concentration of O-H bonds in the precursor water-assisted growth alumina layer provides high-density hydroxyl groups for the bonding surface, which is beneficial to the improvement of the bonding strength; the precursor ozone-assisted growth alumina layer mainly contains O ions and only a small amount of O-H bonds, which provides an effective diffusion channel for the H2O groups formed at the interface during the bonding of the precursor water-assisted growth alumina layer, and the O-H bonds, H bonds and H2O groups remaining at the interface during the subsequent high-temperature process, the O-H bonds, H bonds and H2O groups diffuse into the precursor ozone-assisted growth alumina layer, which reduces the probability of the mutual aggregation of the above-mentioned groups, avoids the high-concentration aggregation of the above-mentioned groups at the local position of the interface and the alumina region adjacent to the interface to form H2O, and thus effectively inhibits the generation of H2O bubbles at the interface and the generation of H2O bubbles in the alumina material. The use of the precursor ozone-assisted growth alumina layer effectively inhibits the generation of H2O bubbles at the interface and the generation of H2O bubbles in the alumina material, so that the wafer bonding device has fewer bubbles, higher bonding rate and bonding effective area of up to 98%. The device of the application can make the bonding strength between wafers reach or even exceed the silicon body strength (2.5 J / m 2 ), and can withstand most subsequent process processing.

[0041] In order to provide sufficient diffusion space for the O-H bonds, H bonds and H2O groups, the thickness of the precursor ozone-assisted growth alumina layer is greater than 2 nm, and is further preferably 3-20 nm, for example, 5 nm, 7 nm, 9 nm, 11 nm, 13 nm, 15 nm, 17 nm, 19 nm, etc.

[0042] In consideration of the bonding strength and bubble inhibition effect of the precursor water-assisted growth alumina layer, the thickness of the precursor water-assisted growth alumina layer is not more than 2 nm, for example, 0.5 nm, 0.7 nm, 1 nm, 1.3 nm, 1.5 nm, 1.7 nm, etc. The thickness of the precursor water-assisted growth alumina layer is too small, which affects the bonding strength; and the thickness is too large, which is not conducive to the diffusion of the O-H bonds, H bonds and H2O groups in the interface and body of the precursor water-assisted growth alumina layer into the precursor ozone-assisted growth alumina layer.

[0043] Exemplarily, the first wafer and the second wafer are silicon wafers or non-silicon wafers, respectively.

[0044] In a second aspect, the application further provides a wafer bonding method based on a composite alumina intermediate layer, a precursor water-assisted growth alumina layer is a wafer bonding layer, and a precursor ozone-assisted growth alumina layer is arranged on the opposite side of the bonding side of the precursor water-assisted growth alumina layer.

[0045] Specifically, as shown in Figures 1-4 the method comprises the following steps:

[0046] Step A: forming a composite alumina layer 3 on the surface of the first wafer 1 and the second wafer 2 respectively, the composite alumina layer 3 includes a precursor ozone-assisted growth alumina layer 301 and a precursor water-assisted growth alumina layer 302 stacked in turn from the wafer surface upwards;

[0047] Step B: performing surface activation treatment on the first wafer 1 and the second wafer 2 containing the composite alumina layer 3;

[0048] Step C: placing the composite alumina layers 3 of the first wafer 1 and the second wafer 2 in contact with each other, and performing bonding treatment.

[0049] It can be understood that in step A, the composite alumina layer 3 is formed on the surface of the first wafer 1 and the second wafer 2 respectively, which includes: forming a precursor ozone-assisted growth alumina layer 301 and a precursor water-assisted growth alumina layer 302 stacked in turn from the surface of the first wafer 1 upwards on the surface of the first wafer 1, to obtain a structure as shown in FIG. 1; similarly, a precursor ozone-assisted growth alumina layer 301 and a precursor water-assisted growth alumina layer 302 stacked in turn from the surface of the second wafer 2 upwards are formed on the surface of the second wafer 2. That is, the alumina layer in contact with the surface of the first wafer 1 and the second wafer 2 is the precursor ozone-assisted growth alumina layer 301. Figure 2

[0050] Compared with the prior art, in the wafer bonding method of the present application, the higher concentration of O-H bonds in the precursor water-assisted growth alumina layer provides a high density of hydroxyl groups for the bonding surface, which is beneficial to the improvement of bonding strength; the O ions in the precursor ozone-assisted growth alumina layer only have a few O-H bonds, which provide an effective diffusion channel for the H2O groups formed at the interface during bonding and the O-H bonds, H bonds and H2O groups remaining at the interface during subsequent high-temperature processes, the O-H bonds, H bonds and H2O groups diffuse into the precursor ozone-assisted growth alumina layer and combine with the high-concentration O ions in the layer to form new groups, thereby effectively inhibiting the generation of H2O bubbles at the interface and the generation of H2O bubbles in the alumina material. The use of the precursor ozone-assisted growth alumina layer effectively inhibits the generation of H2O bubbles at the interface and the generation of H2O bubbles in the alumina material, so that there are fewer bubbles in the wafer bonded device, the bonding rate is higher, and the effective bonding area can reach 98%. The method of the present application can make the bonding strength between wafers reach or even exceed the silicon body strength (2.5 J / m 2 ), and can withstand most subsequent process processing.

[0051] ​Exemplarily, the method further comprises: before forming the composite aluminum oxide layer 3 on the surfaces of the first wafer 1 and the second wafer 2, cleaning the first wafer 1 and the second wafer 2 respectively.

[0052] Specifically, the two wafers are cleaned by using a chemical cleaning method, which comprises: first, cleaning the surface oil stains by using an organic solvent and removing the surface adsorbed particles, and then removing the metal ion contamination by using acid pickling.

[0053] Exemplarily, in step A, the method for forming the composite aluminum oxide layer 3 is ALD deposition method.

[0054] It can be understood that, first, a precursor ozone-assisted growth aluminum oxide layer 301 is deposited on the surface of the wafer by using ALD deposition method, and then a precursor water-assisted growth aluminum oxide layer 302 is deposited on the precursor ozone-assisted growth aluminum oxide layer 301 by using ALD deposition method.

[0055] Specifically, the method for forming the precursor ozone-assisted growth aluminum oxide layer 301 comprises: sequentially introducing trimethylaluminum (TMA), nitrogen, ozone and nitrogen into the cavity as one cycle, and one cycle grows about 0.1 nm of aluminum oxide film; and the method for forming the precursor water-assisted growth aluminum oxide layer 302 comprises: sequentially introducing trimethylaluminum (TMA), nitrogen, deionized water and nitrogen into the cavity as one cycle, and one cycle grows about 0.1 nm of aluminum oxide film.

[0056] Exemplarily, the proportion of Al-O-H bond in the precursor ozone-assisted growth aluminum oxide layer 301 is 0.3-0.6%, for example, the proportion of Al-O bond is 99.4%-99.7%, and the proportion of Al-O-H bond in the precursor water-assisted growth aluminum oxide layer 302 is 48-49%, and the proportion of Al-O bond is 50-51%. It can be seen that the O-H group in the precursor ozone-assisted growth aluminum oxide layer is greatly reduced compared with the precursor water-assisted growth aluminum oxide layer.

[0057] Exemplarily, in step A, the growth temperature of the composite aluminum oxide layer 3 is less than 350℃, for example, 200℃, 220℃, 240℃, 260℃, 280℃, 300℃, 320℃, 340℃, etc. If the growth temperature is too high, the hydroxyl content in the aluminum oxide body and on the surface will be affected, thereby increasing the bonding difficulty.

[0058] In the present application, the purpose of the surface activation treatment in step B is to remove the particles and contamination that may be contained on the surface of the sample, and to make the surface atoms generate high-energy dangling bonds, which is beneficial to bonding.

[0059] Exemplarily, in step B, the surface activation treatment is plasma activation treatment method.

[0060] Specifically, the surface activation treatment activates the composite alumina layer on the surface of the two wafers by using a single plasma such as O2 or Ar, or activates the composite alumina layer on the surface of the wafer by using multiple plasmas such as O2 and Ar.

[0061] Illustratively, the temperature of the surface activation treatment is 16-26℃. Too high temperature will make the wafer surface easily react with ambient atoms to produce byproducts, which is not conducive to bonding.

[0062] Illustratively, the surface activation treatment of step B and the bonding treatment of step C are performed in an activation-bonding integrated machine. After the surface activation treatment, the composite alumina layers of the two wafers are abutted and attached together, and the device applies pressure to them to achieve the bonding of the two wafers under ultra-high vacuum.

[0063] Specifically, in step C, the bonding treatment is performed in a vacuum chamber, and the pressure of the vacuum chamber is 10 -7 -10 -10 Pa. After the surface activation, there are a large number of dangling bonds on the surface of the sample, and the sample is very active and easy to react with other substances, so the reaction between ambient molecules and the surface of the sample should be reduced under ultra-high vacuum.

[0064] Illustratively, in step C, the bonding pressure of the bonding treatment is 100-1000kg. If the bonding pressure is too small, it is not easy to bond, and if the bonding pressure is too high, the wafer is easy to be damaged. The bonding temperature is 16-26℃. After the surface activation, there are a large number of dangling bonds with high activity on the surface of the sample, which are very active and easy to bond with another high-energy activated surface at room temperature.

[0065] The bonding temperature of the present application is room temperature bonding technology, which avoids any damage and destruction caused by heat, and is also suitable for wafers that have been structurally treated.

[0066] In a third aspect, the present application also provides a device comprising a wafer prepared according to the above method.

[0067] In the following, the wafer bonding device and method based on the composite alumina intermediate layer of the present application are further illustrated by specific examples.

[0068] Example 1

[0069] The embodiment provides a wafer bonding device based on a composite alumina intermediate layer, which comprises a first wafer, a second wafer, and a precursor ozone-assisted growth alumina layer, a precursor water-assisted growth alumina layer, a precursor water-assisted growth alumina layer and a precursor ozone-assisted growth alumina layer arranged in sequence from the first wafer to the second wafer and located between the first wafer and the second wafer, and the two precursor water-assisted growth alumina layers are bonded. The thickness of the precursor ozone-assisted growth alumina layer is 10 nm, and the thickness of the precursor water-assisted growth alumina layer is 1.5 nm.

[0070] Embodiment 2

[0071] The embodiment provides a wafer bonding method based on a composite alumina intermediate layer, which is used for preparing the wafer bonding device of embodiment 1, and comprises the following steps.

[0072] Step A: the first wafer and the second wafer are cleaned by using a chemical cleaning method, the surface oil stains are cleaned by using an organic solvent ultrasonic cleaning, and the surface adsorbed particles are removed, and then metal ion contamination is removed by using acid cleaning.

[0073] Step B: by using an ALD deposition method, a precursor ozone-assisted growth alumina layer and a precursor water-assisted growth alumina layer are formed on the surface of the first wafer in sequence from the surface of the first wafer upwards, and a precursor ozone-assisted growth alumina layer and a precursor water-assisted growth alumina layer are formed on the surface of the second wafer in sequence from the surface of the second wafer upwards. The thickness of the precursor ozone-assisted growth alumina layer is 10 nm, and the thickness of the precursor water-assisted growth alumina layer is 1.5 nm.

[0074] Step C: the first wafer and the second wafer containing the composite alumina layer are subjected to surface activation treatment by using a plurality of plasmas at 20℃.

[0075] Step D: the first wafer and the second wafer containing the composite alumina layer after the surface activation treatment are placed in a vacuum cavity with the composite alumina layer surfaces contacting each other, and an external force is applied to bond them; the pressure of the vacuum cavity is 10 -5 Pa, the bonding pressure adopted is 600 kg, and the bonding temperature is 22℃.

[0076] The wafer bonding device obtained in embodiment 2 is subjected to bonding strength test and ultrasonic scanning, the bonding strength is 3J / m 2 , and the ultrasonic scanning result is shown in the following table. Figure 5

[0077] Comparative example 1

[0078] ​The comparative example 2 provides a wafer bonding method similar to the example 2, except that the precursor water-assisted growth alumina layers are directly formed on the surfaces of the first wafer and the second wafer, respectively, and then the precursor water-assisted growth alumina layers on the surfaces of the first wafer and the second wafer are contacted and bonded.

[0079] The wafer bonded device obtained in the comparative example 1 is subjected to ultrasonic scanning, and the ultrasonic scanning result is shown in FIG. 2. Figure 6

[0080] From the ultrasonic scanning results of Figure 5 and Figure 6 It can be seen that the bubbles in the wafer bonded device of the example 2 are significantly less than those in the wafer bonded device of the comparative example 1, because the example 2 adopts the composite alumina intermediate layer, in which the precursor ozone-assisted growth alumina layer mainly contains O ions, and only a small amount of O-H bonds, which provides an effective diffusion channel for the H2O groups formed at the interface during bonding and the O-H bonds, H bonds and H2O groups remaining at the interface during subsequent high-temperature processes. The O-H bonds, H bonds and H2O groups diffuse into the precursor ozone-assisted growth alumina layer, reducing the probability of the above groups aggregating and combining with each other, avoiding the high-concentration aggregation and combination of the above groups at the local position of the interface and the alumina region adjacent to the interface to form H2O, thereby effectively inhibiting the generation of H2O bubbles at the interface and the generation of H2O bubbles in the alumina material. Therefore, the wafer bonded device of the example 2 has fewer bubbles, higher bonding rate, and the bonding effective area reaches 98%.

[0081] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.​

Claims

1. A wafer bonding device based on a composite aluminum oxide interlayer, characterized in that, The device comprises a first wafer, a second wafer, and a precursor ozone-assisted growth alumina layer, a precursor water-assisted growth alumina layer, a precursor water-assisted growth alumina layer and a precursor ozone-assisted growth alumina layer arranged in sequence from the first wafer to the second wafer and located between the first wafer and the second wafer, and the two precursor water-assisted growth alumina layers are bonded.

2. The wafer bond device of claim 1, wherein, The thickness of the precursor ozone-assisted growth alumina layer is greater than 2 nm.

3. The wafer bonded device of claim 1, wherein, The thickness of the precursor water-assisted growth alumina layer is not more than 2 nm.

4. A wafer bonding method based on a composite aluminum oxide interlayer, characterized by, The precursor water-assisted growth alumina layer is a wafer bonding layer, and a precursor ozone-assisted growth alumina layer is arranged on the opposite side of the bonding side of the precursor water-assisted growth alumina layer; the wafer bonding method comprises the following steps: Step A: forming a composite alumina layer on the surface of the first wafer and the second wafer, respectively, the composite alumina layer comprises a precursor ozone-assisted growth alumina layer and a precursor water-assisted growth alumina layer arranged in sequence from the wafer surface upwards; Step B: performing surface activation treatment on the first wafer and the second wafer containing the composite alumina layer; Step C: placing the composite alumina layers of the first wafer and the second wafer in contact with each other for bonding treatment.

5. The method of claim 4, wherein, In step A, the method for forming the composite alumina layer is ALD deposition method.

6. The method of claim 4, wherein, In step A, the growth temperature of the composite alumina layer is less than 350℃.

7. The method of claim 4, wherein, In step B, the surface activation treatment is plasma activation treatment method, and the temperature of the surface activation treatment is 16-26℃.

8. The method of claim 4, wherein, In step C, the bonding process is performed in a vacuum chamber, the pressure of which is in the range of 10 -7 -10 -10 Pa.

9. The method of claim 4, wherein, In step C, the bonding pressure of the bonding treatment is 100-1000 kg, and the bonding temperature is 16-26℃.

10. A device comprising a wafer prepared by the method according to any one of claims 4-9.

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