A Ru / SiO2 hybrid bonding method

Abstract

The application provides a Ru / SiO2 hybrid bonding method, and relates to the technical field of chip manufacturing. The method comprises the following steps: performing plasma activation treatment on a first wafer and a second wafer respectively to obtain a first sample to be bonded and a second sample to be bonded; under the action of a first magnetic field, the first sample to be bonded and the second sample to be bonded are aligned and laminated and pre-bonded to obtain a pre-bonded sample; and the pre-bonded sample is subjected to thermal pressure bonding under the action of a pulse current and a second magnetic field to obtain a hybrid bonding sample; wherein the direction of the pulse current is perpendicular to the bonding interface of the pre-bonded sample, and the direction of the second magnetic field is parallel to the bonding interface of the pre-bonded sample. By using the method, Ru / SiO2 hybrid bonding with high strength can be realized at a lower temperature.

Description

Technical Field

[0001] This invention relates to the field of chip manufacturing technology, and more specifically, to a Ru / SiO2 hybrid bonding method. Background Technology

[0002] With the development of 3D integration, wafer-level packaging, and advanced logic-memory heterogeneous integration technologies, hybrid bonding has attracted widespread attention due to its high interconnect density, low interconnect resistance, and excellent electrical performance. Currently, copper / silicon dioxide (Cu / SiO2) hybrid bonding technology has been mass-produced in some high-end chip products. However, as semiconductor process nodes advance to 3nm and below, device feature sizes continue to shrink, and the linewidth of interconnect structures is approaching the 10nm level, the limitations of traditional Cu-based interconnect technologies are becoming increasingly prominent: First, copper's electromigration reliability is insufficient. Under high current density, copper atoms easily diffuse and migrate along grain boundaries or interfaces, leading to voids or short circuits in the interconnect lines, seriously affecting the long-term stability of the chip. Second, the interface diffusion problem between copper and surrounding dielectric materials is prominent. Copper atoms easily diffuse into dielectric layers such as SiO2, causing dielectric performance degradation and increasing the risk of signal crosstalk. Third, copper has poor thermal stability. Under high-temperature process environments, grain growth is prone to occur, leading to increased interconnect resistance and reduced chip energy efficiency. In addition, Cu / SiO2 hybrid bonding usually requires a high-temperature annealing process above 300°C, which not only increases the process cost, but may also cause thermal damage to sensitive devices in the chip, limiting its application scope in heterogeneous integration scenarios.

[0003] Ruthenium (Ru), as a novel interconnect metal material, possesses a series of excellent physicochemical properties and is considered an ideal candidate to replace copper. Ru has a resistivity of only 7.1 μΩ·cm, close to that of copper (1.7 μΩ·cm), ensuring low resistance characteristics in interconnect circuits. Its melting point is as high as 2334℃, far exceeding copper's 1085℃, exhibiting excellent thermal stability. Simultaneously, Ru's resistance to electromigration is more than 10 times that of copper, and its interfacial diffusion coefficient with dielectric materials such as SiO2 is extremely low, effectively suppressing the impact of metal atom diffusion on device performance. Furthermore, Ru can be directly integrated with the dielectric layer without an additional diffusion barrier layer, further reducing the size of the interconnect structure and increasing integration density.

[0004] Despite the significant performance advantages exhibited by Ru-based interconnect materials, the development of Ru / SiO2 hybrid bonding technology still faces several key challenges. In existing technologies, Ru-Ru direct bonding typically requires high-temperature, high-pressure processes to achieve atomic-level contact. However, the high-temperature environment not only increases process complexity but can also lead to Ru surface oxidation or grain growth, affecting the bonding interface quality. Simultaneously, bonding in the SiO2 dielectric layer requires extremely high surface flatness and cleanliness. The significant differences in surface properties between the Ru metal region and the SiO2 dielectric region make it difficult to achieve high-strength bonding of both metal and dielectric bonds under the same process conditions. Currently, a mature low-temperature Ru / SiO2 hybrid bonding process has not yet been developed in the industry. It is difficult to reduce the process temperature to meet the low thermal budget requirements of heterogeneous integration while ensuring bonding strength and electrical performance, severely restricting the large-scale application of Ru-based interconnect technology in advanced packaging. Therefore, how to achieve high-strength Ru / SiO2 hybrid bonding at lower temperatures has become an urgent technical problem to be solved. Summary of the Invention

[0005] The problem solved by this invention is: how to achieve high-strength Ru / SiO2 mixed bonding at a lower temperature.

[0006] To address the above problems, this invention provides a Ru / SiO2 mixed bonding method, comprising: Step S1: Perform plasma activation treatment on the first wafer and the second wafer respectively to obtain the first sample to be bonded and the second sample to be bonded; wherein, the bonding surfaces of the first wafer and the second wafer both include a Ru metal interconnect region and a SiO2 dielectric region; a ferromagnetic functional layer is provided on the inner side of the Ru metal interconnect region; the plasma gas used in the plasma activation treatment includes Ar, H2, NH3 and H2O; Step S2: Under the action of the first magnetic field, the first sample to be bonded and the second sample to be bonded are aligned, bonded, and pre-bonded to obtain a pre-bonded sample; wherein, the direction of the first magnetic field is parallel to the contact interface between the first sample to be bonded and the second sample to be bonded during the alignment and bonding process. Step S3: The pre-bonded sample is thermo-bonded under the action of a pulsed current and a second magnetic field to obtain a hybrid bonded sample; wherein, the direction of the pulsed current is perpendicular to the bonding interface of the pre-bonded sample, and the direction of the second magnetic field is parallel to the bonding interface of the pre-bonded sample.

[0007] Optionally, in step S1, the volume ratio of Ar, H2, NH3 and H2O in the plasma gas is (2 to 5): (1 to 3): (1 to 2): (1 to 2).

[0008] Optionally, in step S1, the plasma activation treatment time is 1 min to 3 min, and the gas pressure is 0.4 mbar to 0.8 mbar.

[0009] Optionally, in step S1, the surface roughness of both the first wafer and the second wafer is below 0.5 nm.

[0010] Optionally, in step S2, the pre-bonding pressure is 0.1 MPa to 1 MPa, and the time is 5 min to 10 min.

[0011] Optionally, in step S3, the density of the pulse current is 100 A / cm. 2 Up to 10000A / cm 2 The frequency ranges from 0.1 kHz to 10 kHz.

[0012] Optionally, in step S3, the magnetic induction intensity of the second magnetic field is 0.1T to 2T.

[0013] Optionally, in step S3, the temperature of the hot-press bonding is 240°C to 260°C.

[0014] Optionally, in step S3, the pressure of the hot-press bonding is 0.5 MPa to 2 MPa.

[0015] Optionally, in step S3, the hot-press bonding time is 10 min to 60 min.

[0016] Compared with related technologies, this invention first uses a multi-element plasma composed of Ar, H2, NH3 and H2O to activate the sample. The physical bombardment of Ar ions can precisely etch the natural oxide layer on the surface of the Ru metal interconnect region and the micro-nano-scale rough structure of the SiO2 dielectric region, providing a smooth physical basis for subsequent tight bonding of the interface. The reducing atmosphere of H2 further removes residual oxide impurities on the Ru metal surface, exposes Ru active atoms, and avoids the oxide layer from hindering Ru metal bonding. The synergistic effect of NH3 and H2O can introduce a large number of active hydroxyl groups on the surface of the SiO2 dielectric region, making the originally inert SiO2 surface reactive at low temperatures. Dehydration condensation reactions between hydroxyl groups can occur without high temperatures, which is beneficial for obtaining high-strength mixed-bonded samples at lower temperatures. Furthermore, in this invention, because a ferromagnetic functional layer is provided inside the Ru metal interconnect region, a first magnetic field in a specific direction is applied during the alignment and bonding process of the first and second samples to be bonded. Under the action of the first magnetic field, a magnetic dipole moment and magnetic force gradient are generated, thereby automatically correcting the misalignment between the upper and lower samples, which is beneficial to improving the alignment and bonding accuracy, and thus beneficial to improving the strength of the Ru / SiO2 hybrid bond. In addition, during the subsequent hot-pressing bonding process, the pulsed current perpendicular to the bonding interface can quickly focus the Joule heating effect in the Ru metal interconnect region, precisely heating the metal contact interface, avoiding thermal damage to the wafer structure caused by overall high temperature, and enabling Ru atoms to obtain sufficient diffusion kinetic energy at a lower temperature, breaking the dependence of traditional bonding on high-temperature environment; while the second magnetic field parallel to the bonding interface drives Ru atoms to migrate directionally along the interface through Lorentz force, forming a synergy with the thermal effect generated by the pulsed current: the thermal effect generated by the pulsed current enhances atomic activity, and the second magnetic field guides the direction of atomic movement. Under the combined action of the two, Ru atoms can efficiently fill the metal contact gap, achieving atomic-level tight bonding, which is beneficial to obtaining a Ru / SiO2 hybrid bond with high strength. Furthermore, during the hot-press bonding process, a ferromagnetic functional layer introduced into the inner side of the Ru metal interconnect region generates periodic micro-strain under the action of a second magnetic field. This induces a "dynamic compression-release" at the bonding interface, disrupting the residual gaps and thereby increasing the atomic contact rate. This facilitates accelerated diffusion bonding and further enhances the strength of the Ru / SiO2 mixed bond. In summary, the method of this invention enables the achievement of high-strength Ru / SiO2 mixed bonds at relatively low temperatures (240°C to 260°C). Attached Figure Description

[0017] Figure 1 This is a schematic flowchart of the Ru / SiO2 mixed bonding method in an embodiment of the present invention; Figure 2 This is a schematic diagram of the mixed-bonded sample obtained in an embodiment of the present invention. Detailed Implementation

[0018] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0019] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0020] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first," "second," etc., mentioned in this invention are used to distinguish different objects, not to describe a specific order or hierarchy. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0021] It should be noted that, in this invention, the bonding interface of the pre-bonded sample refers to the interface formed by two wafers being bonded face to face in the pre-bonded sample.

[0022] Taking the first wafer as an example, when the bonding surface of the first wafer faces downward, the inner side of the Ru metal interconnect region is the upper side of the Ru metal interconnect region in the first wafer; when the bonding surface of the first wafer faces upward, the inner side of the Ru metal interconnect region is the lower side of the Ru metal interconnect region in the first wafer.

[0023] like Figure 1 As shown, an embodiment of the present invention provides a Ru / SiO2 mixed bonding method, comprising: Step S1: Perform plasma activation treatment on the first wafer and the second wafer respectively to obtain the first sample to be bonded and the second sample to be bonded; wherein, the bonding surfaces of the first wafer and the second wafer both include a Ru metal interconnect region and a SiO2 dielectric region; a ferromagnetic functional layer is provided on the inner side of the Ru metal interconnect region; the plasma gas used in the plasma activation treatment includes Ar, H2, NH3 and H2O; Step S2: Under the action of the first magnetic field, the first sample to be bonded and the second sample to be bonded are aligned, bonded, and pre-bonded to obtain a pre-bonded sample; wherein, the direction of the first magnetic field is parallel to the contact interface between the first sample to be bonded and the second sample to be bonded during the alignment and bonding process. Step S3: The pre-bonded sample is thermo-bonded under the action of a pulsed current and a second magnetic field to obtain a hybrid bonded sample; wherein, the direction of the pulsed current is perpendicular to the bonding interface of the pre-bonded sample, and the direction of the second magnetic field is parallel to the bonding interface of the pre-bonded sample.

[0024] In this embodiment of the invention, the sample is first activated using a multi-element plasma composed of Ar, H2, NH3, and H2O. The physical bombardment of Ar ions precisely etches the natural oxide layer on the surface of the Ru metal interconnect region and the micro-nano-scale rough structure of the SiO2 dielectric region, providing a smooth physical basis for subsequent tight interface bonding. The reducing atmosphere of H2 further removes residual oxide impurities on the Ru metal surface, exposing Ru active atoms and preventing the oxide layer from hindering Ru metal bonding. The synergistic effect of NH3 and H2O introduces a large number of active hydroxyl groups on the surface of the SiO2 dielectric region, giving the originally inert SiO2 surface low-temperature reactivity. Dehydration condensation reactions between hydroxyl groups can occur without high temperatures, which is beneficial for obtaining high-strength mixed-bonded samples at lower temperatures. Furthermore, in this embodiment of the invention, since a ferromagnetic functional layer is provided inside the Ru metal interconnect region, a first magnetic field in a specific direction is applied during the alignment and bonding process of the first and second samples to be bonded. Under the action of the first magnetic field, a magnetic dipole moment and magnetic gradient are generated, thereby automatically correcting the misalignment in the upper and lower samples, which is beneficial to improving the alignment and bonding accuracy, and thus beneficial to improving the strength of the Ru / SiO2 mixed bond. In addition, during the subsequent hot-pressing bonding process, the pulsed current perpendicular to the bonding interface can quickly focus the Joule heating effect in the Ru metal interconnect region, precisely heating the metal contact interface, avoiding thermal damage to the wafer structure caused by the overall high temperature, and enabling Ru atoms to obtain sufficient diffusion kinetic energy at a lower temperature, breaking the dependence of traditional bonding on a high-temperature environment; while the second magnetic field parallel to the bonding interface drives Ru atoms to migrate directionally along the interface through the Lorentz force, forming a synergy with the thermal effect generated by the pulsed current: the thermal effect generated by the pulsed current enhances atomic activity, and the second magnetic field guides the direction of atomic movement. Under the combined action of the two, Ru atoms can efficiently fill the metal contact gap, achieving atomic-level tight bonding, which is beneficial to obtaining a Ru / SiO2 mixed bond with high strength. Furthermore, during the hot-press bonding process, a ferromagnetic functional layer introduced into the inner side of the Ru metal interconnect region generates periodic micro-strain under the action of a second magnetic field, inducing a "dynamic compression-release" at the bonding interface. This disrupts the residual gaps at the bonding interface, thereby increasing the atomic contact rate, which is beneficial for accelerating diffusion bonding and further enhancing the strength of the Ru / SiO2 mixed bond. In summary, the method of this invention can achieve high-strength Ru / SiO2 mixed bonding at relatively low temperatures (240°C to 260°C).

[0025] In some embodiments of the present invention, in step S1, the volume ratio of Ar, H2, NH3 and H2O in the plasma gas is (2 to 5): (1 to 3): (1 to 2): (1 to 2).

[0026] In some embodiments of the present invention, in step S1, the plasma activation treatment time is 1 min to 3 min, and the gas pressure is 0.4 mbar to 0.8 mbar. If the plasma activation treatment time is too short, the activation will be insufficient, resulting in inadequate hydroxyl density; if the plasma activation treatment time is too long, it will lead to excessive surface etching or the introduction of defects. A gas pressure in the range of 0.4 mbar to 0.8 mbar can maintain a stable non-equilibrium plasma, ensuring moderate ion energy, effectively removing contaminants and oxides while avoiding deep damage to the Ru metal interconnect or structural destruction of the SiO2 dielectric layer.

[0027] In some embodiments of the present invention, in step S1, the surface roughness of both the first wafer and the second wafer is below 0.5 nm. In this embodiment, controlling the surface roughness of both the first wafer and the second wafer to be below 0.5 nm results in a larger contact area between Ru and Ru, SiO2 and SiO2, and Ru and SiO2, providing near-ideal physical contact conditions for hydrogen bond formation and metal diffusion under pulsed current in the pre-bonding stage, which is the basis for achieving high-strength hybrid bonding.

[0028] In some embodiments of the present invention, in step S2, the ferromagnetic functional layer material is selected from at least one of Ni, Co and NiFe alloy, and the thickness of the ferromagnetic functional layer is 100 nm to 500 nm; the magnetic induction intensity of the second magnetic field is 0.1 T to 2 T; preferably, the second magnetic field is a non-uniform magnetic field, which can generate different magnetic forces at different positions, thereby achieving a "magnetic tweezers" effect, which is beneficial to improving the accuracy of alignment and bonding.

[0029] In some embodiments of the present invention, in step S2, the pre-bonding pressure is 0.1 MPa to 1 MPa, and the time is 5 min to 10 min.

[0030] In some embodiments of the present invention, in step S3, the density of the pulse current is 100 A / cm². 2 Up to 10000A / cm 2 The frequency ranges from 0.1 kHz to 10 kHz.

[0031] In some embodiments of the present invention, in step S3, the magnetic induction intensity of the second magnetic field is 0.1T to 2T. When the magnetic induction intensity of the second magnetic field is less than 0.1T, the Lorentz force is insufficient to guide atomic migration; when the magnetic induction intensity of the second magnetic field is greater than 2T, it may induce lattice distortion.

[0032] In some embodiments of the present invention, in step S3, the preset pressure is 0.5 MPa to 2 MPa.

[0033] In some embodiments of the present invention, in step S3, the temperature of the hot-press bonding is 240°C to 260°C, the pressure of the hot-press bonding is 0.5MPa to 2MPa, and the time of the hot-press bonding is 10min to 60min.

[0034] The present invention will be further described below with reference to specific embodiments.

[0035] Example 1 A1. The first wafer and the second wafer are subjected to plasma activation treatment respectively to obtain the first sample to be bonded and the second sample to be bonded; wherein, the bonding surfaces of the first wafer and the second wafer both include a Ru metal interconnect region and a SiO2 dielectric region; a ferromagnetic functional layer is provided on the inner side of the Ru metal interconnect region, the ferromagnetic functional layer is made of Ni and has a thickness of 250nm; the plasma gas used in the plasma activation treatment includes Ar, H2, NH3 and H2O; the volume ratio of Ar, H2, NH3 and H2O in the plasma gas is 3:2:1:1; the plasma activation treatment time is 2min and the gas pressure is 0.6mbar.

[0036] A2. Under the action of the first magnetic field, the first sample to be bonded and the second sample to be bonded are aligned and bonded together to obtain a pre-bonded sample; the pre-bonding pressure is 0.5 MPa and the time is 8 min; the direction of the first magnetic field is parallel to the contact interface between the first sample to be bonded and the second sample to be bonded during the alignment and bonding process; the magnetic induction intensity of the second magnetic field is 1.5 T.

[0037] A3. The pre-bonded sample is thermo-bonded under the action of a pulsed current and a second magnetic field to obtain a hybrid bonded sample; wherein, the direction of the pulsed current is perpendicular to the bonding interface of the pre-bonded sample, and the direction of the second magnetic field is parallel to the bonding interface of the pre-bonded sample; the preset pressure is 1 MPa, and the density of the pulsed current is 5000 A / cm². 2 The frequency is 5kHz; the magnetic induction intensity of the second magnetic field is 1T; the temperature of the hot-press bonding is 250℃, the pressure is 1MPa, and the time is 35min.

[0038] Example 2 A1. The first wafer and the second wafer are subjected to plasma activation treatment respectively to obtain the first sample to be bonded and the second sample to be bonded; wherein, the bonding surfaces of the first wafer and the second wafer both include a Ru metal interconnect region and a SiO2 dielectric region; a ferromagnetic functional layer is provided on the inner side of the Ru metal interconnect region, the ferromagnetic functional layer is made of Ni and has a thickness of 250 nm; the plasma gas used in the plasma activation treatment includes Ar, H2, NH3 and H2O; the volume ratio of Ar, H2, NH3 and H2O in the plasma gas is 3:2:1:1; the plasma activation treatment time is 3 min and the gas pressure is 0.4 mbar.

[0039] A2. Under the action of the first magnetic field, the first sample to be bonded and the second sample to be bonded are aligned and bonded together to obtain a pre-bonded sample; the pre-bonding pressure is 1 MPa and the time is 5 min; the direction of the first magnetic field is parallel to the contact interface between the first sample to be bonded and the second sample to be bonded during the alignment and bonding process; the magnetic induction intensity of the second magnetic field is 1.5 T.

[0040] A3. The pre-bonded sample is thermo-bonded under the action of a pulsed current and a second magnetic field to obtain a hybrid bonded sample; wherein, the direction of the pulsed current is perpendicular to the bonding interface of the pre-bonded sample, and the direction of the second magnetic field is parallel to the bonding interface of the pre-bonded sample; the density of the pulsed current is 1000 A / cm. 2 The frequency is 10kHz; the magnetic induction intensity of the second magnetic field is 2T; the temperature of the hot-press bonding is 240℃, the pressure is 2MPa, and the time is 10min.

[0041] Example 3 A1. The first wafer and the second wafer are subjected to plasma activation treatment respectively to obtain the first sample to be bonded and the second sample to be bonded; wherein, the bonding surfaces of the first wafer and the second wafer both include a Ru metal interconnect region and a SiO2 dielectric region; a ferromagnetic functional layer is provided on the inner side of the Ru metal interconnect region, the ferromagnetic functional layer is made of Ni and has a thickness of 250nm; the plasma gas used in the plasma activation treatment includes Ar, H2, NH3 and H2O; the volume ratio of Ar, H2, NH3 and H2O in the plasma gas is 3:2:1:1; the plasma activation treatment time is 1min and the gas pressure is 0.8mbar.

[0042] A2. Under the action of the first magnetic field, the first sample to be bonded and the second sample to be bonded are aligned and bonded together to obtain a pre-bonded sample; the pre-bonding pressure is 0.1 MPa and the time is 10 min; the direction of the first magnetic field is parallel to the contact interface between the first sample to be bonded and the second sample to be bonded during the alignment and bonding process; the magnetic induction intensity of the second magnetic field is 1.5 T.

[0043] A3. The pre-bonded sample is thermo-bonded under the action of a pulsed current and a second magnetic field to obtain a hybrid bonded sample; wherein, the direction of the pulsed current is perpendicular to the bonding interface of the pre-bonded sample, and the direction of the second magnetic field is parallel to the bonding interface of the pre-bonded sample; the density of the pulsed current is 10000 A / cm. 2 The frequency is 0.1kHz; the magnetic induction intensity of the second magnetic field is 0.1T; the temperature of the hot-press bonding is 260℃, the pressure is 0.5MPa, and the time is 60min.

[0044] Comparative Example 1 The difference from Example 1 is that the plasma gas used in the plasma activation treatment includes Ar, NH3 and H2O; the volume ratio of Ar, NH3 and H2O in the plasma gas is 3:1:1.

[0045] Comparative Example 2 (No pulsed current applied) The pre-bonded sample is hot-pressed under the action of a second magnetic field to obtain a hybrid bonded sample; wherein, the direction of the second magnetic field is parallel to the bonding interface of the pre-bonded sample; the magnetic induction intensity of the second magnetic field is 1T; the hot-pressing bonding temperature is 250℃, the pressure is 1MPa, and the time is 35min.

[0046] Comparative Example 3 (No second magnetic field was applied in step A3) The difference from Example 1 is that step A3 is: the pre-bonded sample is hot-pressed and bonded under the action of a pulsed current to obtain a mixed-bonded sample; wherein, the direction of the pulsed current is perpendicular to the bonding interface of the pre-bonded sample, and the density of the pulsed current is 5000 A / cm. 2 The frequency is 5kHz; the hot-press bonding temperature is 250℃, the pressure is 1MPa, and the time is 35min.

[0047] Effect Example The tensile strength of the mixed-bonded samples prepared in Examples 1 to 3 and Comparative Examples 1 to 3 was tested, and the results are shown in Table 1. As can be seen from Table 1, the tensile strength of the mixed-bonded samples prepared in Examples 1 to 3 is higher than that of Comparative Examples 1 to 3.

[0048] Table 1

[0049] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A Ru / SiO2 mixed bonding method, characterized in that, include: Step S1: Perform plasma activation treatment on the first wafer and the second wafer respectively to obtain the first sample to be bonded and the second sample to be bonded; wherein, the bonding surfaces of the first wafer and the second wafer both include a Ru metal interconnect region and a SiO2 dielectric region; a ferromagnetic functional layer is provided on the inner side of the Ru metal interconnect region; the plasma gas used in the plasma activation treatment includes Ar, H2, NH3 and H2O; Step S2: Under the action of the first magnetic field, the first sample to be bonded and the second sample to be bonded are aligned, bonded, and pre-bonded to obtain a pre-bonded sample; wherein, the direction of the first magnetic field is parallel to the contact interface between the first sample to be bonded and the second sample to be bonded during the alignment and bonding process. Step S3: The pre-bonded sample is thermo-bonded under the action of a pulsed current and a second magnetic field to obtain a hybrid bonded sample; wherein, the direction of the pulsed current is perpendicular to the bonding interface of the pre-bonded sample, and the direction of the second magnetic field is parallel to the bonding interface of the pre-bonded sample.

2. The Ru / SiO2 mixed bonding method according to claim 1, characterized in that, In step S1, the volume ratio of Ar, H2, NH3 and H2O in the plasma gas is (2 to 5): (1 to 3): (1 to 2): (1 to 2).

3. The Ru / SiO2 mixed bonding method according to claim 1, characterized in that, In step S1, the plasma activation treatment time is 1 min to 3 min, and the gas pressure is 0.4 mbar to 0.8 mbar.

4. The Ru / SiO2 mixed bonding method according to claim 1, characterized in that, In step S1, the surface roughness of both the first wafer and the second wafer is below 0.5 nm.

5. The Ru / SiO2 mixed bonding method according to claim 1, characterized in that, In step S2, the pre-bonding pressure is 0.1 MPa to 1 MPa, and the time is 5 min to 10 min.

6. The Ru / SiO2 mixed bonding method according to claim 1, characterized in that, In step S3, the density of the pulse current is 100 A / cm². 2 Up to 10000A / cm 2 The frequency ranges from 0.1 kHz to 10 kHz.

7. The Ru / SiO2 hybrid bonding method according to claim 1, characterized in that, In step S3, the magnetic induction intensity of the second magnetic field is 0.1T to 2T.

8. The Ru / SiO2 hybrid bonding method according to claim 1, characterized in that, In step S3, the temperature of the hot-press bonding is 240°C to 260°C.

9. The Ru / SiO2 mixed bonding method according to claim 1, characterized in that, In step S3, the pressure of the hot-press bonding is 0.5 MPa to 2 MPa.

10. The Ru / SiO2 mixed bonding method according to claim 1, characterized in that, In step S3, the hot-press bonding time is 10 min to 60 min.

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