SiC / InP heterogeneous wafer bonding method based on magnetron sputtering amorphous silicon

Abstract

The invention relates to the technical field of chip manufacturing, in particular to a SiC / InP heterogeneous wafer bonding method based on magnetron sputtering amorphous silicon. Comprising the following steps: S1, providing a first wafer and a second wafer, and depositing interface layers on bonding surfaces of the first wafer and the second wafer through a magnetron sputtering method to realize homogeneous interface conversion of heterogeneous wafers; s2, activating the interface layer by adopting plasma; and S3, carrying out pre-bonding treatment on the bonding surfaces of the first wafer and the second wafer, and carrying out low-temperature annealing treatment to obtain the heterogeneous wafer. According to the method, the ultrathin nanoscale silicon material interface layers are formed on the surfaces of the heterogeneous wafers through the magnetron sputtering method and the amorphous silicon sputtering technology, homogeneous interface conversion of the heterogeneous wafers is achieved, and the normal-temperature direct bonding capacity of the heterogeneous wafers is improved; and meanwhile, a plasma surface activation technology is adopted to activate a silicon material interface layer, remove surface impurities of an amorphous silicon layer and improve the surface activity of amorphous silicon, so that ultrathin interface bonding of SiC and InP heterogeneous wafers is realized.

Description

Technical Field

[0001] The invention relates to the technical field of chip manufacturing, and in particular to a SiC / InP heterogeneous wafer bonding method based on magnetron sputtering of amorphous silicon. Background Art

[0002] Wafer bonding is an advanced manufacturing technology that combines polished semiconductor wafers. This technology has a wide range of applications in microelectronics manufacturing, micro-electromechanical system packaging, multifunctional chip integration, and other emerging fields. Traditional high-temperature bonding methods are no longer suitable for some temperature-sensitive devices or materials with large differences in thermal expansion coefficients. Therefore, achieving strong bonding at lower annealing temperatures or even at room temperature without heating has become a challenge in the field of wafer bonding.

[0003] Silicon carbide (SiC) and indium phosphide (InP) are two semiconductor materials with important advantages. SiC can withstand higher currents and voltages, has higher switching speeds and less energy loss, and performs well in high temperature environments. Therefore, power modules made of SiC can significantly reduce the components of capacitors, inductors, coils, and heat dissipation components, making the entire power device module lighter, more energy-efficient, with stronger output power and enhanced reliability. At the same time, InP has the advantages of high saturated electron drift velocity, strong radiation resistance, good thermal conductivity, and high photoelectric conversion efficiency, and its wafer substrate has a high transmittance in the mid-wavelength infrared. Because the two materials have similar thermal expansion coefficients and lattice constants, they have become one of the ideal materials for heterogeneous bonding. This heterogeneous bonding technology can give full play to the advantages of the two materials and bring more possibilities and application prospects to the fields of microelectronics manufacturing and optoelectronic devices.

[0004] Existing wafer bonding methods have the following disadvantages: (1) When wet activation bonding is used, the concentration and treatment degree of the solution cannot be effectively controlled, and other phenomena such as metal contamination and chemical corrosion may occur; (2) When surface activated bonding (SAB) is used, ① this method is not applicable to oxide wafers (such as silicon dioxide, quartz and glass), the bonding strength at room temperature is very low, and a high-temperature annealing process is still required; ② this method requires a high vacuum system, and the equipment is complex and expensive; (3) When a single plasma surface activation technology is used, after the surface of the heterogeneous wafer material is activated, the void rate of the bonded wafer is high and the bonding strength is not high; (4) When selecting materials, factors such as the thermal expansion coefficient, lattice matching, and chemical properties of the material need to be considered when bonding heterogeneous wafers to ensure the stability and reliability of the bonding; (5) When other methods such as wet activation are used to complete SiC / InP heterogeneous wafer bonding, the strength is not high enough or it directly appears as unbonded. Summary of the invention

[0005] In view of this, the present invention proposes a SiC / InP heterogeneous wafer bonding method based on magnetron sputtering amorphous silicon to solve the technical problems of thick heterogeneous wafer bonding interface, poor bonding quality and high process requirements in the prior art.

[0006] The technical solution of the present invention is implemented as follows: The present invention provides a SiC / InP heterogeneous wafer bonding method based on magnetron sputtering amorphous silicon, comprising the following steps:

[0007] S1. Providing a first wafer and a second wafer, and depositing an interface layer on the bonding surfaces of the first wafer and the second wafer by a magnetron sputtering method to achieve homogeneous interface conversion of heterogeneous wafers;

[0008] S2, using plasma to activate the interface layer;

[0009] S3, performing a pre-bonding treatment on the bonding surfaces of the first wafer and the second wafer, and performing a low-temperature annealing treatment to obtain a heterogeneous wafer.

[0010] On the basis of the above technical solution, preferably, the material of the first wafer is SiC, and the material of the second wafer is InP.

[0011] In the present invention, a uniform amorphous silicon interface layer is deposited on the wafer surface of different materials such as SiC and InP to form a homogenous interface structure, wherein the deposition process parameters are accurately controlled by magnetron sputtering technology to prepare a high-quality amorphous silicon interface layer, and this homogenous interface is conducive to the subsequent bonding process. Then the interface layer can be activated by plasma treatment to produce a large number of active groups, such as hydroxyl (-OH), etc., to increase the interatomic force of the bonding interface. The homogenized interface reduces the interface mismatch, and the plasma activation optimizes the bonding interface properties, and the two cooperate with each other to greatly improve the bonding strength and interface stability of the heterogeneous wafer. This synergistic effect ensures that the subsequent pre-bonding and low-temperature annealing treatment can be carried out smoothly, and a high-quality heterogeneous wafer structure is obtained. Pre-bonding forms initial bonding at low temperatures, and can further promote interatomic diffusion during the low-temperature annealing process, eliminate defects and stress at the interface, thereby obtaining a heterogeneous wafer with stable structure and excellent interface performance.

[0012] On the basis of the above technical solution, preferably, after the interface layer is deposited in step S1, the interface layer surfaces of the first wafer and the second wafer are pretreated, and the pretreatment specifically includes:

[0013] The interface surface of the first wafer and the second wafer is cleaned with an alkaline cleaning agent for 8-12 minutes, and then with an acid cleaning agent for 8-12 minutes, and finally with a DHF cleaning agent for 2-3 minutes. After each cleaning, ultrapure water is used for secondary cleaning, and the interface surface of the wafer is blown dry with nitrogen.

[0014] On the basis of the above technical solution, preferably, the composition of the alkaline cleaning agent includes: ammonia water, hydrogen peroxide and water in a volume ratio of 0.8-1.2:1:5; the composition of the acidic cleaning agent includes: hydrochloric acid, hydrogen peroxide and water in a volume ratio of 0.8-1.2:1:6; the composition of the DHF cleaning agent includes: hydrofluoric acid and water in a volume ratio of 1:8-12.

[0015] Specifically, alkaline cleaning is performed first, in which the synergistic effect of ammonia and hydrogen peroxide can oxidize and dissolve silicon, oxides and organic pollutants on the surface of the wafer interface layer; then acid cleaning is performed, in which hydrochloric acid and hydrogen peroxide are highly corrosive and can further dissolve and oxidize alkaline residues and trace metals on the surface of the wafer interface layer; finally, DHF cleaning is performed, in which hydrofluoric acid can chemically react with silicon oxide on the surface of the wafer interface layer to generate soluble hexafluorosilicates, thereby removing surface oxides and silicon dioxide and reducing surface metals.

[0016] On the basis of the above technical solutions, preferably, the magnetron sputtering method controls the plasma by creating a magnetic field, so that the sputtered particles are more efficiently deposited on the substrate, and the ultra-thin nano-scale silicon material interface layer is deposited on the bonding surface of the SiC and InP wafers, so as to realize the homogeneous interface conversion of heterogeneous wafers. Among them, the magnetron sputtering method controls the plasma by creating a magnetic field, specifically including: (1) setting a ring-shaped magnetron array between the target material and the substrate inside the vacuum chamber; (2) connecting the radio frequency power supply to the magnetron array to form a radio frequency driven magnetron sputtering system; (3) controlling the magnetic field strength and the distribution of magnetic field lines generated by the magnetron by adjusting the magnetron sputtering parameters.

[0017] Based on the above technical scheme, preferably, the process parameters of the magnetron sputtering method in step S1 include: the target material is an amorphous silicon target, the sputtering pressure is 1Pa-2Pa, the sputtering power is 10W-20W, the gas used for magnetron sputtering is argon, the argon flow rate is 50sccm-60sccm, and the sputtering time is 30s-60s.

[0018] Specifically, during magnetron sputtering, Ar +Ion bombardment on the surface of the silicon target will cause the physical escape and ejection of atoms on the surface of the silicon target. These broken atoms will be splashed onto the surface of the substrate (wafer) in the form of atoms or molecules, forming a thin film deposition and obtaining a silicon interface layer.

[0019] On the basis of the above technical solution, preferably, in step S1, the material of the interface layer is nano-silicon, and the thickness of the interface layer is 100nm-200nm.

[0020] Nanoscale silicon can form a dense, flat homogeneous interface with SiC and InP at the atomic level, with very few interface defects and impurities; as a semiconductor material, nanosilicon has excellent electrical properties such as carrier mobility, which is beneficial to the electrical properties of heterostructures. The nanoscale thickness of 100-200nm can minimize the stress accumulation between materials while ensuring sufficient strength and electrical integrity.

[0021] On the basis of the above technical solution, preferably, the process parameters of the plasma activation method in step S2 include: in a pure oxygen atmosphere, a power of 200-300 W, an activation treatment time of 30-90 s, and an oxygen flow rate of 150-250 ml / min.

[0022] The prepared SiC and InP samples are placed in a plasma activation device, and pure oxygen plasma is used to activate the ultra-thin silicon interface layer on the surface of SiC and InP. The principle is to use chemical methods to remove surface impurities. It is that the inorganic gas is excited into a plasma state, and then the plasma gas phase high-energy material is sprayed on the surface to be treated. Then, the solid surface molecules react with the adsorbed high-energy groups to decompose and generate gas phase products that detach from the surface, generate free radicals and expose the high-energy surface. This surface chemical activation process is beneficial to the deposition and bonding of the subsequent interface layer, and improves the adhesion of the interface.

[0023] On the basis of the above technical solution, preferably, in step S3, the pressure of the pre-bonding treatment is 0.8-1.2 MPa, and the treatment time is 8-24 h.

[0024] On the basis of the above technical solution, preferably, in step S3, the temperature of the low-temperature annealing treatment is 200-300° C., and the annealing time is 12-24 hours.

[0025] By depositing a nanoscale silicon interface layer with a thickness of only 100-200nm on the wafer bonding surface and activating the silicon interface layer through plasma, the pretreatment effectively activates the interface, promotes atomic migration and bonding, and promotes low-temperature annealing of the bonding surface under relatively mild conditions of 200-300℃ to achieve a high-quality bonding interface, greatly reducing the energy consumption and complexity of the process.

[0026] On the other hand, the present invention provides a heterogeneous wafer prepared by the heterogeneous wafer bonding method as described in any one of the above items, and the thickness of the bonding layer of the heterogeneous wafer is 10-30nm.

[0027] The SiC / InP heterogeneous wafer bonding method based on magnetron sputtering amorphous silicon of the present invention has the following beneficial effects compared with the prior art:

[0028] (1) The present invention forms an ultra-thin nanometer-scale silicon interface layer on the surface of a heterogeneous wafer by magnetron sputtering amorphous silicon, thereby realizing homogeneous conversion of the surface of the heterogeneous wafer. Due to the silicon interface layer deposited on the surface of the heterogeneous wafer, the problems of thermal stress and lattice mismatch are eliminated, thereby greatly improving the bonding strength of the wafer;

[0029] (2) On this basis, plasma surface activation technology is used to activate the silicon material interface layer, remove surface impurities of the amorphous silicon layer, and improve the surface activity of amorphous silicon, so as to achieve ultra-thin interface bonding of SiC and InP heterogeneous wafers and improve the bonding quality;

[0030] (3) The synergistic effect of the ultra-thin nanoscale silicon interface layer and plasma surface activation can improve the bonding strength of heterogeneous wafers, allowing the subsequent annealing process to be carried out at a low temperature (<300°C), further avoiding problems such as thermal stress and lattice mismatch caused by high temperature. At the same time, the preparation process is simple and does not require high temperature, high pressure, or a strict vacuum environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 The present invention is a preparation flow chart of the SiC / InP heterogeneous wafer bonding method based on magnetron sputtering amorphous silicon;

[0033] Figure 2 This is a schematic diagram of the process of preparing the interface layer by magnetron sputtering of the present invention;

[0034] Figure 3 It is a schematic diagram of the principle of the plasma activated interface layer of the present invention;

[0035] Figure 4 This is a SEM image of the heterogeneous wafer prepared in Example 2 of the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Example 1

[0038] This embodiment discloses a SiC / InP heterogeneous wafer bonding method based on magnetron sputtering of amorphous silicon. Figure 1 As shown, the specific steps include:

[0039] (1) providing a first wafer and a second wafer, wherein the material of the first wafer is SiC and the material of the second wafer is InP, using ultrasonic cleaning of the target material, the first wafer and the second wafer, and depositing an interface layer on the bonding surface of the first wafer and the second wafer by magnetron sputtering to achieve homogeneous interface conversion of heterogeneous wafers (such as Figure 2 As shown), specifically comprising: inside a vacuum chamber, setting an annular magnetron array between a target material and a substrate; connecting a radio frequency power supply to the magnetron array to form a radio frequency driven magnetron sputtering system; controlling the magnetic field intensity and the distribution of magnetic field lines generated by the magnetron by adjusting magnetron sputtering parameters, and setting the magnetron sputtering parameters as follows: the plasma used in magnetron sputtering is Ar, the target material used is an amorphous silicon target, the sputtering pressure is 1.5 Pa, the sputtering power is 15 W, the argon gas flow rate is 55 sccm, the sputtering time is 45 s, and the thickness of the deposited interface layer is 150 nm.

[0040] (2) Plasma activation of the interface layer (see the specific activation principle) Figure 3 ), place the first wafer and the second wafer on a glass sheet, and then place them on the placement table in the plasma equipment, set the parameters as follows: select pure oxygen as the gas, set the power to 250W, set the processing time to 60s, and set the flow rate to 200ml / min. After the processing, rinse again with ultrapure water.

[0041] (3) Use tweezers to fit the bonding surfaces of the first wafer and the second wafer together. The UPW remaining on the surface can achieve automatic centering. Then put them into the fixture for pre-bonding treatment, apply a pressure of 1Mpa, and perform pre-bonding pressure for 16 hours. After the pre-bonding is completed, put the wafer into a muffle furnace, set the temperature to 250°C, and anneal for 18 hours. After the annealing is completed, wait for it to cool naturally to room temperature, and then take out the bonded wafer.

[0042] Example 2

[0043] This embodiment discloses a SiC / InP heterogeneous wafer bonding method based on magnetron sputtering of amorphous silicon. The specific operation steps are the same as those in Embodiment 1, except that: in step (1), after depositing the interface layer, the interface layer surface of the first wafer and the second wafer is pretreated, and the pretreatment includes:

[0044] An alkaline cleaning agent (ammonia water, hydrogen peroxide and ultrapure water in a volume ratio of 1:1:5) is used to clean the interface layer surface of the first wafer and the second wafer for 10 minutes. After cleaning, the wafers are cleaned with ultrapure water and blown dry with nitrogen; then an acidic cleaning agent (hydrochloric acid, hydrogen peroxide and ultrapure water in a volume ratio of 1:1:6) is used to clean the interface layer surface of the first wafer and the second wafer for 10 minutes. After cleaning, the wafers are cleaned with ultrapure water and blown dry with nitrogen; finally, a DHF cleaning agent (hydrofluoric acid and ultrapure water in a volume ratio of 1:10) is used to clean the bonding surface of the first wafer and the second wafer for 2 minutes. After cleaning, the wafers are cleaned with ultrapure water and blown dry with nitrogen.

[0045] Example 3

[0046] This embodiment discloses a SiC / InP heterogeneous wafer bonding method based on magnetron sputtering amorphous silicon, which specifically includes the following steps:

[0047] (1) A first wafer and a second wafer are provided, wherein the material of the first wafer is SiC and the material of the second wafer is InP. An interface layer is deposited on the bonding surfaces of the first wafer and the second wafer by magnetron sputtering to achieve homogeneous interface conversion of heterogeneous wafers, specifically comprising: setting an annular magnetron array between the target material and the substrate inside a vacuum chamber; connecting a radio frequency power supply to the magnetron array to form a radio frequency driven magnetron sputtering system; controlling the magnetic field intensity and the distribution of magnetic field lines generated by the magnetron by adjusting the magnetron sputtering parameters, and setting the magnetron sputtering parameters as follows: the plasma used in the magnetron sputtering is Ar, the target material used is an amorphous silicon target, the sputtering pressure is 1 Pa, the sputtering power is 10 W, the argon gas flow rate is 50 sccm, the sputtering time is 30 s, and the thickness of the deposited interface layer is 100 nm.

[0048] An alkaline cleaning agent (ammonia water, hydrogen peroxide and ultrapure water in a volume ratio of 0.8:1:5) is used to clean the interface layer surface of the first wafer and the second wafer for 8 minutes. After cleaning, the wafers are cleaned with ultrapure water and blown dry with nitrogen; then an acidic cleaning agent (hydrochloric acid, hydrogen peroxide and ultrapure water in a volume ratio of 0.8:1:6) is used to clean the interface layer surface of the first wafer and the second wafer for 8 minutes. After cleaning, the wafers are cleaned with ultrapure water and blown dry with nitrogen; finally, a DHF cleaning agent (hydrofluoric acid and ultrapure water in a volume ratio of 1:8) is used to clean the interface layer surface of the first wafer and the second wafer for 2 minutes. After cleaning, the wafers are cleaned with ultrapure water and blown dry with nitrogen.

[0049] (2) Plasma is used to activate the interface layer. The first wafer and the second wafer are placed on a glass sheet, and then placed on a placement table in the plasma equipment. The parameters are set as follows: pure oxygen is selected as the gas, the power is set between 200 W, the treatment time is 30 s, and the flow rate is set to 150 ml / min. After the treatment, rinse again with ultrapure water.

[0050] (3) Use tweezers to fit the bonding surfaces of the first wafer and the second wafer together. The UPW remaining on the surface can achieve automatic centering. Then put them into the fixture for pre-bonding treatment, apply a pressure of 0.8Mpa, and perform pre-bonding pressure for 8 hours. After the pre-bonding is completed, put the wafer into a muffle furnace, set the temperature to 200°C, and anneal for 12 hours. After the annealing is completed, wait for it to cool naturally to room temperature, and then take out the bonded wafer.

[0051] Example 4

[0052] This embodiment discloses a SiC / InP heterogeneous wafer bonding method based on magnetron sputtering amorphous silicon, which specifically includes the following steps:

[0053] (1) A first wafer and a second wafer are provided, wherein the material of the first wafer is SiC and the material of the second wafer is InP. An interface layer is deposited on the bonding surfaces of the first wafer and the second wafer by magnetron sputtering to achieve homogeneous interface conversion of heterogeneous wafers, specifically comprising: setting an annular magnetron array between the target material and the substrate inside a vacuum chamber; connecting a radio frequency power supply to the magnetron array to form a radio frequency driven magnetron sputtering system; controlling the magnetic field intensity and the distribution of magnetic field lines generated by the magnetron by adjusting the magnetron sputtering parameters, and setting the magnetron sputtering parameters as follows: the plasma used in the magnetron sputtering is Ar, the target material used is an amorphous silicon target, the sputtering pressure is 2 Pa, the sputtering power is 20 W, the argon gas flow rate is 60 sccm, the sputtering time is 60 s, and the thickness of the deposited interface layer is 200 nm.

[0054] An alkaline cleaning agent (ammonia water, hydrogen peroxide and ultrapure water in a volume ratio of 1.2:1:5) is used to clean the interface layer surface of the first wafer and the second wafer for 12 minutes. After cleaning, the wafers are cleaned with ultrapure water and blown dry with nitrogen; then an acidic cleaning agent (hydrochloric acid, hydrogen peroxide and water in a volume ratio of 1.2:1:6) is used to clean the interface layer surface of the first wafer and the second wafer for 12 minutes. After cleaning, the wafers are cleaned with ultrapure water and blown dry with nitrogen; finally, a DHF cleaning agent (hydrofluoric acid and ultrapure water in a volume ratio of 1:12) is used to clean the interface layer of the first wafer and the second wafer for 3 minutes. After cleaning, the wafers are cleaned with ultrapure water and blown dry with nitrogen.

[0055] (2) Plasma is used to activate the interface layer. The first wafer and the second wafer are placed on a glass sheet, and then placed on a placement table in the plasma equipment. The parameters are set as follows: pure oxygen is selected as the gas, the power is set between 300 W, the treatment time is between 90 s, and the flow rate is set to 250 ml / min. After the treatment, rinse again with ultrapure water.

[0056] (3) Use tweezers to fit the bonding surfaces of the first wafer and the second wafer together. The UPW remaining on the surface can achieve automatic centering. Then put them into the fixture for pre-bonding treatment, apply a pressure of 1.2Mpa, and perform pre-bonding pressure for 24 hours. After the pre-bonding is completed, put the wafer into a muffle furnace, set the temperature to 300°C, and anneal for 24 hours. After the annealing is completed, wait for it to cool naturally to room temperature, and then take out the bonded wafer.

[0057] Example 5

[0058] This embodiment discloses a SiC / InP heterogeneous wafer bonding method based on magnetron sputtering of amorphous silicon. The specific operation steps are the same as those in Example 2, except that: in step (1), the parameters of magnetron sputtering are set as follows: the plasma used in magnetron sputtering is Ar, the target material used is an amorphous silicon target, the sputtering pressure is 1.5 Pa, the sputtering power is 5 W, the argon gas flow rate is 55 sccm, the sputtering time is 20 s, and the thickness of the deposited interface layer is 50 nm.

[0059] Example 6

[0060] This embodiment discloses a SiC / InP heterogeneous wafer bonding method based on magnetron sputtering of amorphous silicon. The specific operation steps are the same as those of Example 2, except that: in step (1), the parameters of magnetron sputtering are set as follows: the plasma used in magnetron sputtering is Ar, the target material used is an amorphous silicon target, the sputtering pressure is 1.5 Pa, the sputtering power is 25 W, the argon gas flow rate is 55 sccm, the sputtering time is 60 s, and the thickness of the deposited interface layer is 250 nm.

[0061] This comparative example discloses a heterogeneous wafer bonding method, which specifically includes the following steps:

[0062] (1) A first wafer and a second wafer are provided, wherein the material of the first wafer is SiC and the material of the second wafer is InP. An alkaline cleaning agent (ammonia water, hydrogen peroxide and ultrapure water in a volume ratio of 1:1:5) is used to clean the bonding surface of the first wafer and the second wafer for 10 minutes. After cleaning, the wafers are cleaned with ultrapure water and blown dry with nitrogen. Then, an acidic cleaning agent (hydrochloric acid, hydrogen peroxide and ultrapure water in a volume ratio of 1:1:6) is used to clean the bonding surface of the first wafer and the second wafer for 10 minutes. After cleaning, the wafers are cleaned with ultrapure water and blown dry with nitrogen. Finally, a DHF cleaning agent (hydrofluoric acid and ultrapure water in a volume ratio of 1:10) is used to clean the bonding surface of the first wafer and the second wafer for 10 minutes. After cleaning, the wafers are cleaned with ultrapure water and blown dry with nitrogen.

[0063] (2) Plasma is used to activate the interface layer. The first wafer and the second wafer are placed on a glass sheet, and then placed on a placement table in the plasma equipment. The parameters are set as follows: pure oxygen is selected as the gas, the power is set between 250 W, the treatment time is 60 s, and the flow rate is set to 200 ml / min. After the treatment, rinse again with ultrapure water.

[0064] (3) Use tweezers to fit the bonding surfaces of the first wafer and the second wafer together. The UPW remaining on the surface can achieve automatic centering. Then put them into the fixture for pre-bonding treatment, apply a pressure of 1Mpa, and perform pre-bonding pressure for 16 hours. After the pre-bonding is completed, put the wafer into a muffle furnace, set the temperature to 250°C, and anneal for 18 hours. After the annealing is completed, wait for it to cool naturally to room temperature, and then take out the bonded wafer.

[0065] Performance Testing

[0066] The bonding quality of the heterogeneous wafers prepared in the embodiment and the comparative example was tested, wherein the test indexes included the bonding layer thickness and bonding defects, and the bonding defects of the heterogeneous wafers were tested by ultrasonic scanning (C-SAM), that is, the two wafers bonded together were immersed in deionized water, and ultrasonic scanning was performed to check whether there were bonding defects between the two wafers. The test results are shown in Table 1.

[0067] Table 1

[0068]

[0069] Figure 4 The SEM image of the heterogeneous wafer prepared in Example 2 of the present invention is shown. It can be seen from the image that the SiC wafer and the InP wafer are well bonded, and a uniform bonding layer can be seen between the two wafers.

[0070] It can be seen from Table 1 that, by comparing Examples 1-2, it can be seen that pre-treating the wafer can prevent metal ions and contaminants on the wafer surface from affecting wafer bonding, causing wafer stratification or peeling; by comparing Examples 2-4, it can be seen that the technical solution of the present invention can better achieve ultra-thin bonding; by comparing Example 2 with Comparative Example 1, it can be seen that depositing an interface layer on the wafer surface to achieve homogeneous conversion of heterogeneous wafers is beneficial to improving the wafer bonding quality, and no interface layer is set in Comparative Example 1, so it is difficult to perform good bonding; by comparing Example 2 with Examples 5 and 6, it can be seen that if the interface layer is too thin, it is difficult to achieve the effect of homogeneous conversion, which will affect wafer bonding. Although a too thick interface layer can achieve wafer bonding, it will increase resistance and affect device performance.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A SiC / InP heterogeneous wafer bonding method based on magnetron sputtering amorphous silicon, characterized in that: The following steps are involved: S1. Providing a first wafer and a second wafer, and depositing an interface layer on the bonding surfaces of the first wafer and the second wafer by a magnetron sputtering method to achieve homogeneous interface conversion of heterogeneous wafers; S2, using plasma to activate the interface layer; S3, performing a pre-bonding treatment on the bonding surfaces of the first wafer and the second wafer, and performing a low-temperature annealing treatment to obtain a heterogeneous wafer.

2. A SiC / InP heterogeneous wafer bonding method based on magnetron sputtering of amorphous silicon as claimed in claim 1, characterized in that: The material of the first wafer is SiC, and the material of the second wafer is InP.

3. A SiC / InP heterogeneous wafer bonding method based on magnetron sputtering of amorphous silicon as claimed in claim 1, characterized in that: After the interface layer is deposited in step S1, the interface layer surfaces of the first wafer and the second wafer are pretreated. The pretreatment specifically includes: The interface layer between the first wafer and the second wafer is cleaned with an alkaline cleaning agent for 8-12 minutes, and then with an acidic cleaning agent for 8-12 minutes, and finally with a DHF cleaning agent for 2-3 minutes.

4. A SiC / InP heterogeneous wafer bonding method based on magnetron sputtering of amorphous silicon as claimed in claim 3, characterized in that: The alkaline cleaning agent comprises: ammonia water, hydrogen peroxide and water in a volume ratio of 0.8-1.2:1:5; the acidic cleaning agent comprises: hydrochloric acid, hydrogen peroxide and water in a volume ratio of 0.8-1.2:1:6; the DHF cleaning agent comprises: hydrofluoric acid and water in a volume ratio of 1:8-12.

5. A SiC / InP heterogeneous wafer bonding method based on magnetron sputtering of amorphous silicon as claimed in claim 1, characterized in that: The process parameters of the magnetron sputtering method in step S1 include: the target material is an amorphous silicon target, the sputtering pressure is 1Pa-2Pa, the sputtering power is 10W-20W, the gas used in the magnetron sputtering is argon, the argon flow rate is 50sccm-60sccm, and the sputtering time is 30s-60s.

6. A SiC / InP heterogeneous wafer bonding method based on magnetron sputtering of amorphous silicon as claimed in claim 1, characterized in that: In step S1, the material of the interface layer is nano-silicon, and the thickness of the interface layer is 100nm-200nm.

7. A SiC / InP heterogeneous wafer bonding method based on magnetron sputtering of amorphous silicon as claimed in claim 1, characterized in that: The process parameters of the plasma activation method in step S2 include: in a pure oxygen atmosphere, a power of 200-300 W, an activation treatment time of 30-90 s, and an oxygen flow rate of 150-250 ml / min.

8. A SiC / InP heterogeneous wafer bonding method based on magnetron sputtering of amorphous silicon as claimed in claim 1, characterized in that: In step S3, the pressure of the pre-bonding treatment is 0.8-1.2 MPa, and the treatment time is 8-24 hours.

9. A SiC / InP heterogeneous wafer bonding method based on magnetron sputtering of amorphous silicon as claimed in claim 1, characterized in that: In step S3, the temperature of the low temperature annealing treatment is 200-300° C., and the annealing time is 12-24 hours.

10. A heterogeneous wafer, characterized in that: The heterogeneous wafer is prepared by the heterogeneous wafer bonding method according to any one of claims 1 to 9, and the thickness of the bonding layer of the heterogeneous wafer is 10-30 nm.

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