Compound semiconductor wafer high vacuum bonding apparatus and method

Abstract

The application relates to the technical field of wafer bonding, in particular to a compound semiconductor wafer high-vacuum bonding device and method, which solves the technical problems of high dislocation density of high-temperature epitaxial layers, wafer warping, large wafer interface thermal resistance and easy heat crosstalk during integration of different compound wafers, and the device comprises a high-vacuum transmission unit and a plurality of functional units which are distributed along the circumference of the high-vacuum transmission unit at intervals, the functional units comprise a feeding unit, a pretreatment unit, an activation unit, a film coating unit, an alignment unit, a bonding unit and a discharging unit, the high-vacuum transmission unit is connected with a vacuum supply system, the high-vacuum transmission unit is provided with a vacuum operation cavity, operation windows are formed in the side wall of the vacuum operation cavity and correspond to each functional unit, a vacuum manipulator is arranged in the vacuum operation cavity, and the vacuum manipulator is used for penetrating through the operation windows and extending into the corresponding functional units to realize wafer transfer.

Description

Technical Field

[0001] This invention relates to the field of wafer bonding technology, and more particularly to a high-vacuum bonding apparatus and method for compound semiconductor wafers. Background Technology

[0002] As silicon-based semiconductors approach their physical limits in miniaturization, their performance bottlenecks in high-frequency, high-voltage, and optoelectronic applications are becoming increasingly apparent. Compound semiconductor integration has become a core path to overcome these bottlenecks and achieve performance beyond Moore's Law. Compound semiconductors (GaN, SiC, GaAs, etc.) exhibit unparalleled advantages over silicon-based semiconductors in power electronics, radio frequency microwaves, and optoelectronics due to their wider bandgap, higher breakdown field strength, and electron saturation velocity. Currently, compound semiconductor wafer integration technology has evolved from discrete devices and monolithic integration to heterogeneous integration, achieving complementary advantages between silicon-based CMOS and compound semiconductors to meet the extreme performance requirements of high-end applications.

[0003] Compound semiconductor integration still faces significant differences in the thermal expansion coefficients of different materials and wafer lattices, resulting in high dislocation density in high-temperature epitaxial layers and easy wafer warping. At the same time, high-frequency and high-voltage devices have extremely high heat flux densities, and the interface thermal resistance of different compound wafers is large and prone to thermal crosstalk, affecting device performance and lifespan. Therefore, traditional compound semiconductor wafer heteroepitaxial technology is not suitable for the technical requirements of compound wafer heterointegration. Summary of the Invention

[0004] To overcome the technical defects of high dislocation density in high-temperature epitaxial layers, easy wafer warping, and large thermal resistance at wafer interfaces that easily generate thermal crosstalk when integrating different compound wafers, this invention provides a high-vacuum bonding device and method for compound semiconductor wafers.

[0005] The present invention provides a high vacuum bonding device for compound semiconductor wafers, including a high vacuum transmission unit and a plurality of functional units distributed circumferentially along the high vacuum transmission unit. The functional units include a loading unit, a pretreatment unit, an activation unit, a coating unit, an alignment unit, a bonding unit and a unloading unit. The high vacuum transmission unit is connected to a vacuum supply system.

[0006] The high vacuum transmission unit is equipped with a vacuum operation chamber. The side wall of the vacuum operation chamber has operation windows corresponding to each functional unit. A vacuum manipulator is installed in the vacuum operation chamber. The vacuum manipulator is used to penetrate the operation window and extend into the corresponding functional unit to realize the transfer of the wafer.

[0007] The feeding unit is equipped with a feeding vacuum chamber. A docking window is opened on the side wall of the feeding vacuum chamber. The docking window of the feeding vacuum chamber is sealed and connected to the corresponding operation window on the high vacuum transmission unit through the first partition valve. The feeding unit is used to place a material box containing compound wafers to be processed.

[0008] A pre-alignment unit is provided in the vacuum operation chamber between the high vacuum transmission unit and the loading unit. The pre-alignment unit is used to locate the flat edge or notch of the compound wafer.

[0009] The pretreatment unit is equipped with a pretreatment vacuum chamber. The pretreatment vacuum chamber has a docking window on its side wall. The docking window of the pretreatment vacuum chamber is sealed to the corresponding operation window on the high vacuum transmission unit through a second diaphragm valve. The pretreatment unit is used to bake the compound wafer to remove moisture from the surface of the compound wafer.

[0010] The activation unit is equipped with an activation vacuum chamber, and a docking window is opened on the side wall of the activation vacuum chamber. The docking window of the activation vacuum chamber is sealed to the corresponding operation window on the high vacuum transmission unit through a third diaphragm valve. The activation unit is used to realize the surface activation of compound wafers.

[0011] The coating unit is equipped with a coating vacuum chamber. A docking window is opened on the side wall of the coating vacuum chamber. The docking window of the coating vacuum chamber is sealed to the corresponding operation window on the high vacuum transmission unit through a fourth diaphragm valve. The coating unit is used to sputter a transition layer on the surface of the compound wafer.

[0012] The alignment unit is equipped with an alignment vacuum chamber, and a docking window is opened on the side wall of the alignment vacuum chamber. The docking window of the alignment vacuum chamber is sealed to the corresponding operation window on the high vacuum transmission unit through a fifth diaphragm valve. The alignment unit is used to align two compound wafers.

[0013] The bonding unit is equipped with a bonding vacuum chamber, and a docking window is opened on the side wall of the bonding vacuum chamber. The docking window of the bonding vacuum chamber is sealed and connected to the corresponding operation window on the high vacuum transmission unit through the sixth partition valve. The bonding unit achieves wafer bonding by applying pressure to two compound wafers.

[0014] The unloading unit is equipped with an unloading vacuum chamber. A docking window is opened on the side wall of the unloading vacuum chamber. The docking window of the unloading vacuum chamber is sealed and connected to the corresponding operation window on the high vacuum transmission unit through the seventh partition valve. The unloading unit is used to place the material box containing the bonded wafers.

[0015] A flipping unit is provided in the vacuum operating cavity between the high vacuum transmission unit and the feeding unit. The flipping unit is equipped with a flipping mechanism for flipping the compound wafer.

[0016] Preferably, the feeding vacuum chamber is equipped with a feeding box lifting mechanism, and the unloading vacuum chamber is equipped with a unloading box lifting mechanism. Both the feeding vacuum chamber and the unloading vacuum chamber are connected to the vacuum supply system.

[0017] Preferably, the pretreatment vacuum chamber is equipped with a hot plate and a wafer lifting mechanism, and is connected to the vacuum supply system.

[0018] Preferably, the activation unit is provided with a first wafer carrier stage and an atomic gun, the atomic gun is connected to an activation power supply, and the activation vacuum chamber is connected to a vacuum supply system.

[0019] Preferably, the coating vacuum chamber is equipped with a target material, a second wafer support stage, and an ion beam generator. The ion beam generator is connected to an radio frequency power supply, and the coating vacuum chamber is connected to a vacuum supply system.

[0020] Preferably, the alignment vacuum chamber is equipped with a motion mechanism, a lower support stage, a vision system, and a pre-bonding mechanism, and is connected to the vacuum supply system.

[0021] Preferably, the bonding vacuum chamber is provided with an upper pressure stage mechanism, a lower pressure stage mechanism and a corresponding driving mechanism, and the bonding vacuum chamber is connected to the vacuum supply system.

[0022] Preferably, the feeding unit, pretreatment unit, activation unit, alignment unit, bonding unit, coating unit, and unloading unit are arranged sequentially and at intervals along the circumference of the high vacuum transfer unit.

[0023] A high-vacuum bonding method for compound semiconductor wafers, based on the high-vacuum bonding apparatus for compound semiconductor wafers described in this invention, includes the following steps:

[0024] S1: The compound wafers to be processed are placed sequentially into the feed box of the feeding unit, and the vacuum degree of the feeding vacuum chamber reaches 1×10⁻⁶. -5 Pa, the material box lifting mechanism moves its inner material box to the material feeding position in the material feeding vacuum chamber;

[0025] S2: Open the first diaphragm valve, use a vacuum robot to pick up the first compound wafer from the loading vacuum chamber, and transfer it to the pre-alignment unit, then close the first diaphragm valve;

[0026] S3: The pre-alignment unit completes the search for the flat edge or notch of the first compound wafer and performs coarse alignment;

[0027] S4: Open the second diaphragm valve, the vacuum robot picks up the first compound wafer in the pre-aligned vacuum chamber and transfers it to the wafer lifting mechanism in the pre-processing vacuum chamber. Close the second diaphragm valve, and provide a vacuum environment to the pre-processing vacuum chamber through the vacuum supply system. The wafer lifting mechanism descends to bring the first compound wafer closer to the hot plate, and the pre-processing process is started to bake the first compound wafer to remove moisture from its surface. Open the second diaphragm valve again, and the wafer lifting mechanism rises to move the first compound wafer away from the hot plate. The vacuum robot picks up the first compound wafer in the pre-processing vacuum chamber and enters the vacuum operation chamber of the high vacuum transmission unit. Close the second diaphragm valve again.

[0028] S5: Open the third diaphragm valve, the vacuum robot transfers the first compound wafer to the first wafer stage of the activation vacuum chamber, close the third diaphragm valve, the vacuum supply system provides a vacuum environment for the activation vacuum chamber, the activation unit starts the activation process, the activation power supply and the atomic gun work together to generate a plasma beam or atomic beam, irradiating the surface of the first compound wafer to complete the removal of surface oxides and contaminants from the first compound wafer; open the third diaphragm valve again, the vacuum robot picks up the first compound wafer from the first wafer stage and enters the vacuum operating chamber of the high vacuum transfer unit, and closes the third diaphragm valve;

[0029] S6: Open the fourth diaphragm valve, the vacuum robot transfers the first compound wafer to the second wafer carrier stage of the coating unit, close the fourth diaphragm valve, the vacuum supply system provides a vacuum environment for the coating vacuum chamber, start the coating process, the radio frequency power supply and ion beam generator excite and generate an ion beam, and irradiate the target material, sputtering the target material onto the first compound wafer on the second wafer carrier stage, so that a uniform transition layer film is formed on the surface of the first compound wafer; open the fourth diaphragm valve again, the vacuum robot picks up the first compound wafer on the second wafer carrier stage and enters the vacuum operation chamber of the high vacuum transmission unit, and close the fourth diaphragm valve again;

[0030] S7: The vacuum robot transfers the first compound wafer to the flipping mechanism of the flipping unit. After the first compound wafer is flipped by the flipping mechanism, the vacuum robot picks up the first compound wafer and enters the vacuum operation chamber of the high vacuum transmission unit.

[0031] S8: Open the fifth diaphragm valve, the vacuum robot transfers the first compound wafer to the alignment unit, the first compound wafer is adsorbed onto the pre-bonding mechanism in the alignment vacuum chamber, waiting for the second compound wafer, close the fifth diaphragm valve, and the vacuum supply system provides a vacuum environment for the alignment vacuum chamber;

[0032] S9: Repeat S1-S6 to complete the pre-processing of the second compound wafer, open the fifth diaphragm valve, and the vacuum robot will transfer the second compound wafer to the lower support stage of the alignment vacuum chamber. The alignment of the first and second compound wafers will be completed through the cooperation of the vision system and the motion mechanism. At the same time, the pre-bonding mechanism will descend, so that the first and second compound wafers will come into contact and press together, completing the pre-bonding of the first and second compound wafers and forming a pre-bonded wafer pair.

[0033] S10: Open the sixth diaphragm valve. The vacuum robot transfers the pre-bonded wafer pair to the lower pressure stage mechanism of the bonding vacuum chamber. Close the sixth diaphragm valve. The vacuum supply system provides a vacuum environment for the alignment vacuum chamber. The drive mechanism in the alignment vacuum chamber drives the upper pressure stage mechanism to descend, thereby pressing the pre-bonded wafer pair onto the lower pressure stage mechanism, completing the bonding process and obtaining a bonded wafer pair. Open the sixth diaphragm valve again. The vacuum robot picks up the bonded wafer pair and enters the vacuum operating chamber of the high vacuum transfer unit. Close the sixth diaphragm valve again.

[0034] S11: Open the seventh partition valve. The vacuum robot takes the bonding wafer pair out of the alignment vacuum chamber and transfers it to the unloading vacuum chamber. The unloading cassette lift adjusts the height of the cassette. The bonding wafer pair is placed in the cassette of the unloading unit. The vacuum robot leaves the unloading vacuum chamber and closes the seventh partition valve, thus completing one wafer bonding process.

[0035] Preferably, in S4, the pretreatment temperature in the pretreatment unit is ≤400℃; in S6, the target material in the coating unit is selected from one of silicon target, ceramic target and metal target; in S9, the vision system performs edge alignment or surface marking alignment on the first compound wafer and the second compound wafer; in S10, the maximum bonding pressure of the upper pressure stage mechanism and the lower pressure stage mechanism in the bonding unit is 100Kn and the maximum bonding temperature is 200℃.

[0036] Compared with existing technologies, the technical solution provided by this invention has the following technical advantages: The compound semiconductor wafer vacuum bonding device and method described in this invention overcomes the limitations of lattice matching. By directly "attaching" a pre-prepared high-quality compound semiconductor thin film to the target substrate, the lattice matching requirement is completely bypassed, enabling heterogeneous integration of arbitrary material combinations and greatly expanding the freedom of material selection. This invention also avoids damage to materials caused by high-temperature growth environments. Heteroepitaxy typically requires high temperatures (often above 1000°C), which can cause severe damage to the formed devices or materials, leading to warping or even cracking during high-temperature cooling. This invention, however, can be completed at lower temperatures, avoiding damage to sensitive materials and better preserving their intrinsic properties. The process described in this invention is simpler, lower in cost, and more suitable for mass production. The process is simpler, does not require complex gas environments and high-temperature conditions, reduces dependence on expensive epitaxial equipment, and is more suitable for large-scale mass production. Attached Figure Description

[0037] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is an overall assembly diagram of a high-vacuum bonding apparatus for compound semiconductor wafers according to a certain embodiment of the present invention;

[0040] Figure 2 This is a schematic diagram of the feeding unit and the unloading unit according to a certain embodiment of the present invention;

[0041] Figure 3 This is a schematic diagram of the preprocessing unit in a certain embodiment of the present invention;

[0042] Figure 4 This is a schematic diagram of the flipping unit in a certain embodiment of the present invention;

[0043] Figure 5 This is a schematic diagram of the activation unit in a certain embodiment of the present invention;

[0044] Figure 6 This is a schematic diagram of the coating unit described in a certain embodiment of the present invention;

[0045] Figure 7 This is a schematic diagram of the alignment unit according to a certain embodiment of the present invention;

[0046] Figure 8 This is a schematic diagram of the bonding unit described in a certain embodiment of the present invention;

[0047] Figure 9 This is a schematic diagram of the high vacuum transmission unit described in a certain embodiment of the present invention.

[0048] In the diagram: 1. High-vacuum transfer unit; 101. Vacuum operating chamber; 102. Vacuum robot; 2. Loading unit; 201. Loading vacuum chamber; 202. First diaphragm valve; 203. Loading tray lifting mechanism; 3. Pre-processing unit; 301. Pre-processing vacuum chamber; 302. Second diaphragm valve; 303. Hot plate; 304. Wafer lifting mechanism; 4. Activation unit; 401. Activation vacuum chamber; 402. Third diaphragm valve; 403. First wafer support stage; 404. Atomic gun; 405. Activation power supply; 5. Coating unit; 501. Coating vacuum chamber; 502. Fourth diaphragm valve; 503. Target material; 504. Second wafer. 505. Support stage; 506. Ion beam generator; 507. Radio frequency power supply; 6. Alignment unit; 608. Alignment vacuum chamber; 609. Fifth diaphragm valve; 6000. Motion mechanism; 6001. Lower support stage; 601. Vision system; 602. Pre-bonding mechanism; 7. Bonding unit; 701. Bonding vacuum chamber; 702. Sixth diaphragm valve; 703. Upper pressure stage mechanism; 704. Lower pressure stage mechanism; 705. Drive mechanism; 8. Unloading unit; 801. Unloading vacuum chamber; 802. Seventh diaphragm valve; 803. Unloading box lifting mechanism; 9. Vacuum supply system; 13. Pre-alignment unit; 14. Tilting unit; 1401. Tilting mechanism. Detailed Implementation

[0049] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0050] In this description, it should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. It should also be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joint" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0051] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.

[0052] The following is in conjunction with the appendix Figures 1 to 9 Specific embodiments of the present invention will be described in detail below.

[0053] In one embodiment, a high vacuum bonding apparatus for compound semiconductor wafers is disclosed, including a high vacuum transmission unit 1 and a plurality of functional units distributed circumferentially along the high vacuum transmission unit 1. The functional units include a loading unit 2, a pretreatment unit 3, an activation unit 4, a coating unit 5, an alignment unit 6, a bonding unit 7, and a unloading unit 8. The high vacuum transmission unit 1 is connected to a vacuum supply system 9.

[0054] The high vacuum transmission unit 1 is provided with a vacuum operation chamber 101. The side wall of the vacuum operation chamber 101 has operation windows corresponding to each functional unit. A vacuum manipulator 102 is provided in the vacuum operation chamber 101. The vacuum manipulator 102 is used to penetrate the operation window and extend into the corresponding functional unit to realize the transfer of the wafer.

[0055] The loading unit 2 is provided with a loading vacuum chamber 201. A docking window is opened on the side wall of the loading vacuum chamber 201. The docking window of the loading vacuum chamber 201 is sealed and connected to the corresponding operation window on the high vacuum transmission unit 1 through the first partition valve 202. The loading unit 2 is used to place a material box containing compound wafers to be processed.

[0056] A pre-alignment unit 13 is provided in the vacuum operation cavity 101 between the high vacuum transmission unit 1 and the loading unit 2. The pre-alignment unit 13 is used to find the flat edge or notch of the compound wafer.

[0057] The pretreatment unit 3 is equipped with a pretreatment vacuum chamber 301. A docking window is opened on the side wall of the pretreatment vacuum chamber 301. The docking window of the pretreatment vacuum chamber 301 is sealed and connected to the corresponding operation window on the high vacuum transmission unit 1 through the second partition valve 302. The pretreatment unit 3 is used to bake the compound wafer to remove moisture from the surface of the compound wafer. This can improve the bonding success rate and reduce bonding defects.

[0058] The activation unit 4 is equipped with an activation vacuum chamber 401. The activation vacuum chamber 401 has a docking window on its side wall. The docking window of the activation vacuum chamber 401 is sealed to the corresponding operation window on the high vacuum transmission unit 1 through the third partition valve 402. The activation unit 4 is used to realize the surface activation of the compound wafer. The activation unit 4 can use a fast atomic beam activation process or an ion beam activation process.

[0059] The coating unit 5 is equipped with a coating vacuum chamber 501. A docking window is opened on the side wall of the coating vacuum chamber 501. The docking window of the coating vacuum chamber 501 is sealed and connected to the corresponding operation window on the high vacuum transmission unit 1 through the fourth partition valve 502. The coating unit 5 is used to sputter a transition layer on the surface of the compound wafer. The intermediate transition layer is heterobonded between different compound wafers to meet different process requirements. The coating unit 5 can use fast atomic beam irradiation technology, ion beam irradiation technology, magnetron sputtering technology or electron cyclotron resonance technology.

[0060] The alignment unit 6 is provided with an alignment vacuum chamber 601. A docking window is opened on the side wall of the alignment vacuum chamber 601. The docking window of the alignment vacuum chamber 601 is sealed and connected to the corresponding operation window on the high vacuum transmission unit 1 through the fifth diaphragm valve 602. The alignment unit 6 is used to align two compound wafers. The alignment unit 6 realizes the precise alignment of two compound wafers.

[0061] The bonding unit 7 is provided with a bonding vacuum chamber 701. A docking window is opened on the side wall of the bonding vacuum chamber 701. The docking window of the bonding vacuum chamber 701 is sealed and connected to the corresponding operation window on the high vacuum transmission unit 1 through the sixth partition valve 702. The bonding unit 7 achieves wafer bonding by applying pressure to two compound wafers.

[0062] The unloading unit 8 is provided with an unloading vacuum chamber 801. A docking window is opened on the side wall of the unloading vacuum chamber 801. The docking window of the unloading vacuum chamber 801 is sealed and connected to the corresponding operation window on the high vacuum transmission unit 1 through the seventh partition valve 802. The unloading unit 8 is used to place the material box containing the bonded wafer.

[0063] A flipping unit 14 is provided in the vacuum operating cavity 101 between the high vacuum transmission unit 1 and the feeding unit 8. The flipping unit 14 is provided with a flipping mechanism 1401 for flipping the compound wafer.

[0064] Based on the above embodiments, in a preferred embodiment, a feeding box lifting mechanism 203 is provided in the feeding vacuum chamber 201, and a discharging box lifting mechanism 803 is provided in the discharging vacuum chamber 801. Both the feeding vacuum chamber 201 and the discharging vacuum chamber 801 are connected to the vacuum supply system 9.

[0065] Based on the above embodiments, in a preferred embodiment, the pretreatment vacuum chamber 301 is provided with a hot plate 303 and a wafer lifting mechanism 304, and is connected to the vacuum supply system 9.

[0066] Based on the above embodiments, in a preferred embodiment, the activation unit 4 is provided with a first wafer carrier stage 403 and an atomic gun 404, the atomic gun 404 is connected to an activation power supply 405, and the activation vacuum chamber 401 is connected to the vacuum supply system 9.

[0067] Based on the above embodiments, in a preferred embodiment, the coating vacuum chamber 501 is provided with a target material 503, a second wafer support stage 504 and an ion beam generator 505, the ion beam generator 505 is connected to an RF power supply 506, and the coating vacuum chamber 501 is connected to the vacuum supply system 9.

[0068] Based on the above embodiments, in a preferred embodiment, the alignment vacuum cavity 601 is provided with a motion mechanism 603, a lower support stage 604, a vision system 605 and a pre-bonding mechanism 606, and is connected to the vacuum supply system 9.

[0069] Based on the above embodiments, in a preferred embodiment, the bonding vacuum cavity 701 is provided with an upper pressure stage mechanism 703, a lower pressure stage mechanism 704 and a corresponding driving mechanism 705, and the bonding vacuum cavity 701 is connected to the vacuum supply system 9.

[0070] Based on the above embodiments, in a preferred embodiment, the feeding unit 2, pretreatment unit 3, activation unit 4, alignment unit 6, bonding unit 7, coating unit 5 and unloading unit 8 are arranged sequentially at intervals along the circumference of the high vacuum transfer unit 1.

[0071] In this device, the connection and cooperation of the components in the feeding unit 2, pretreatment unit 3, activation unit 4, alignment unit 6, bonding unit 7, coating unit 5, unloading unit 8, pre-alignment unit 13 and flipping unit 14 are existing.

[0072] A high-vacuum bonding method for compound semiconductor wafers, based on the high-vacuum bonding apparatus for compound semiconductor wafers described in this invention, includes the following steps:

[0073] S1: The compound wafers to be processed are placed sequentially into the feed box of the feeding unit 2. The vacuum degree of the feeding vacuum chamber 201 reaches 1×10-5Pa. The feeding box lifting mechanism 203 moves the inner box to the feeding position in the feeding vacuum chamber 201.

[0074] S2: Open the first diaphragm valve 202, use the vacuum robot 102 to pick up the first compound wafer from the loading vacuum chamber 201, and transfer it to the pre-alignment unit 13, then close the first diaphragm valve 202.

[0075] S3: The pre-alignment unit 13 completes the search for the flat edge or Notch of the first compound wafer and performs coarse alignment;

[0076] S4: Open the second diaphragm valve 302, the vacuum robot 102 picks up the first compound wafer in the pre-aligned vacuum chamber 601 and transfers it to the wafer lifting mechanism 304 of the pre-processing vacuum chamber 301. Close the second diaphragm valve 302, and provide a vacuum environment for the pre-processing vacuum chamber 301 through the vacuum supply system 9. The wafer lifting mechanism 304 descends to bring the first compound wafer closer to the hot plate 303, and the pre-processing process is started to bake the first compound wafer to remove moisture from its surface. Open the second diaphragm valve 302 again, and the wafer lifting mechanism 304 rises to move the first compound wafer away from the hot plate 303. The vacuum robot 102 picks up the first compound wafer in the pre-processing vacuum chamber 301 and enters the vacuum operation chamber 101 of the high vacuum transmission unit 1. Close the second diaphragm valve 302 again.

[0077] S5: Open the third diaphragm valve 402, and the vacuum robot 102 transfers the first compound wafer to the first wafer support stage 403 of the activation vacuum chamber 401. Close the third diaphragm valve 402, and the vacuum supply system 9 provides a vacuum environment for the activation vacuum chamber 401. The activation unit 4 starts the activation process, and the activation power supply 405 and the atomic gun 404 work together to generate a plasma beam or atomic beam to irradiate the surface of the first compound wafer, completing the removal of oxides and contaminants from the surface of the first compound wafer. Then, the third diaphragm valve 402 opens again, and the vacuum robot 102 picks up the first compound wafer from the first wafer support stage 403 and enters the vacuum operation chamber 101 of the high vacuum transmission unit 1. Close the third diaphragm valve 402.

[0078] S6: Open the fourth partition valve 502, the vacuum robot 102 transfers the first compound wafer to the second wafer support stage 504 of the coating unit 5, close the fourth partition valve 502, the vacuum supply system 9 provides a vacuum environment for the coating vacuum chamber 501, start the coating process, the radio frequency power supply 506 and the ion beam generator 505 excite and generate an ion beam, and irradiate the target material 503, sputtering the target material 503 onto the first compound wafer on the second wafer support stage 504, so that a uniform transition layer film is formed on the surface of the first compound wafer; open the fourth partition valve 502 again, the vacuum robot 102 picks up the first compound wafer on the second wafer support stage 504 and enters the vacuum operation chamber 101 of the high vacuum transmission unit 1, and close the fourth partition valve 502 again;

[0079] S7: The vacuum robot 102 transfers the first compound wafer to the flipping mechanism 1401 of the flipping unit 14. After the first compound wafer is flipped by the flipping mechanism 1401, the vacuum robot 102 picks up the first compound wafer and enters the vacuum operation chamber 101 of the high vacuum transmission unit 1.

[0080] S8: Open the fifth diaphragm valve 602, the vacuum robot 102 transfers the first compound wafer to the alignment unit 6, the first compound wafer is adsorbed onto the pre-bonding mechanism 606 in the alignment vacuum chamber 601, waiting for the second compound wafer, close the fifth diaphragm valve 602, and the vacuum supply system 9 provides a vacuum environment for the alignment vacuum chamber 601.

[0081] S9: Repeat S1-S6 to complete the pre-processing of the second compound wafer. Open the fifth diaphragm valve 602. The vacuum robot 102 transfers the second compound wafer to the lower support stage 604 of the alignment vacuum chamber 601. The alignment of the first and second compound wafers is completed through the cooperation of the vision system 605 and the motion mechanism 603. At the same time, the pre-bonding mechanism 606 descends, so that the first and second compound wafers come into contact and press together, completing the pre-bonding of the first and second compound wafers and forming a pre-bonded wafer pair.

[0082] S10: Open the sixth partition valve 702. The vacuum robot 102 transfers the pre-bonded wafer pair to the lower pressure stage mechanism 704 of the bonding vacuum chamber 701. Close the sixth partition valve 702. The vacuum supply system 9 provides a vacuum environment for the alignment vacuum chamber 601. The drive mechanism 705 in the alignment vacuum chamber 601 drives the upper pressure stage mechanism 703 to descend, thereby pressing the pre-bonded wafer pair on the lower pressure stage mechanism 704 to complete the bonding process and obtain a bonded wafer pair. Open the sixth partition valve 702 again. The vacuum robot 102 picks up the bonded wafer pair and enters the vacuum operation chamber 101 of the high vacuum transmission unit 1. Close the sixth partition valve 702 again.

[0083] S11: Open the seventh partition valve 802. After the vacuum robot 102 takes the bonding wafer pair out of the alignment vacuum chamber 601, it is transferred to the unloading vacuum chamber 801. The unloading box lift adjusts the height of the box. The bonding wafer pair is placed in the box of the unloading unit 8. The vacuum robot 102 withdraws from the unloading vacuum chamber 801 and closes the seventh partition valve 802, thus completing one wafer bonding process.

[0084] The above embodiments are only one high-vacuum bonding method for compound semiconductor wafers. The high-vacuum bonding apparatus for compound semiconductor wafers described in this invention can achieve different process combinations, such as bonding process routes that do not go through the coating unit 5, or bonding process routes that do not go through the coating unit 5 and the alignment unit 6.

[0085] Based on the above embodiments, in a preferred embodiment, in S4, the pretreatment temperature in the pretreatment unit 3 is ≤400℃; in S6, the target material 503 in the coating unit 5 is selected from one of silicon target, ceramic target and metal target; in S9, the vision system 605 performs edge alignment or surface marking alignment on the first compound wafer and the second compound wafer; in S10, the maximum bonding pressure of the upper pressure stage mechanism 703 and the lower pressure stage mechanism 704 in the bonding unit 7 is 100Kn and the maximum bonding temperature is 200℃.

[0086] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the present invention. Although detailed descriptions have been provided with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments, and they should all be covered within the protection scope of the claims.

Claims

1. A high-vacuum bonding apparatus for compound semiconductor wafers, characterized in that, It includes a high vacuum transmission unit (1) and multiple functional units distributed circumferentially along the high vacuum transmission unit (1). The functional units include a loading unit (2), a pretreatment unit (3), an activation unit (4), a coating unit (5), an alignment unit (6), a bonding unit (7), and a unloading unit (8). The high vacuum transmission unit (1) is connected to a vacuum supply system (9). The high vacuum transmission unit (1) is provided with a vacuum operation chamber (101). The side wall of the vacuum operation chamber (101) has operation windows corresponding to each functional unit. A vacuum manipulator (102) is provided in the vacuum operation chamber (101). The vacuum manipulator (102) is used to penetrate the operation window and extend into the corresponding functional unit to realize the transfer of the wafer. The loading unit (2) is provided with a loading vacuum chamber (201). A docking window is opened on the side wall of the loading vacuum chamber (201). The docking window of the loading vacuum chamber (201) is sealed and connected to the corresponding operation window on the high vacuum transmission unit (1) through the first partition valve (202). The loading unit (2) is used to place a material box containing compound wafers to be processed. A pre-alignment unit (13) is provided in the vacuum operation cavity (101) between the high vacuum transfer unit (1) and the loading unit (2). The pre-alignment unit (13) is used to find the flat edge or Notch of the compound wafer. The pretreatment unit (3) is provided with a pretreatment vacuum chamber (301). A docking window is opened on the side wall of the pretreatment vacuum chamber (301). The docking window of the pretreatment vacuum chamber (301) is sealed and connected to the corresponding operation window on the high vacuum transmission unit (1) through the second partition valve (302). The pretreatment unit (3) is used to bake the compound wafer to remove the water vapor on the surface of the compound wafer. The activation unit (4) is provided with an activation vacuum chamber (401). A docking window is opened on the side wall of the activation vacuum chamber (401). The docking window of the activation vacuum chamber (401) is sealed and connected to the corresponding operation window on the high vacuum transmission unit (1) through the third diaphragm valve (402). The activation unit (4) is used to realize the surface activation of the compound wafer. The coating unit (5) is provided with a coating vacuum chamber (501). A docking window is opened on the side wall of the coating vacuum chamber (501). The docking window of the coating vacuum chamber (501) is sealed and connected to the corresponding operation window on the high vacuum transmission unit (1) through the fourth partition valve (502). The coating unit (5) is used to sputter a transition layer on the surface of the compound wafer. The alignment unit (6) is provided with an alignment vacuum chamber (601). A docking window is opened on the side wall of the alignment vacuum chamber (601). The docking window of the alignment vacuum chamber (601) is sealed and connected to the corresponding operation window on the high vacuum transmission unit (1) through the fifth diaphragm valve (602). The alignment unit (6) is used to align two compound wafers. The bonding unit (7) is provided with a bonding vacuum chamber (701). A docking window is opened on the side wall of the bonding vacuum chamber (701). The docking window of the bonding vacuum chamber (701) is sealed and connected to the corresponding operation window on the high vacuum transmission unit (1) through the sixth partition valve (702). The bonding unit (7) achieves wafer bonding by applying pressure to two compound wafers. The unloading unit (8) is provided with an unloading vacuum chamber (801). A docking window is opened on the side wall of the unloading vacuum chamber (801). The docking window of the unloading vacuum chamber (801) is sealed and connected to the corresponding operation window on the high vacuum transmission unit (1) through the seventh partition valve (802). The unloading unit (8) is used to place a material box containing bonded wafers. A flipping unit (14) is provided in the vacuum operation cavity (101) between the high vacuum transmission unit (1) and the feeding unit (8). The flipping unit (14) is provided with a flipping mechanism (1401) for flipping the compound wafer.

2. The high-vacuum bonding apparatus for compound semiconductor wafers according to claim 1, characterized in that, The loading vacuum chamber (201) is equipped with a loading box lifting mechanism (203), and the unloading vacuum chamber (801) is equipped with an unloading box lifting mechanism (803). Both the loading vacuum chamber (201) and the unloading vacuum chamber (801) are connected to the vacuum supply system (9).

3. The high-vacuum bonding apparatus for compound semiconductor wafers according to claim 2, characterized in that, The pretreatment vacuum chamber (301) is equipped with a hot plate (303) and a wafer lifting mechanism (304), and is connected to the vacuum supply system (9).

4. The high-vacuum bonding apparatus for compound semiconductor wafers according to claim 3, characterized in that, The activation unit (4) is equipped with a first wafer carrier stage (403) and an atomic gun (404). The atomic gun (404) is connected to an activation power supply (405), and the activation vacuum chamber (401) is connected to the vacuum supply system (9).

5. The high-vacuum bonding apparatus for compound semiconductor wafers according to claim 4, characterized in that, The coating vacuum chamber (501) is equipped with a target material (503), a second wafer support stage (504) and an ion beam generator (505). The ion beam generator (505) is connected to a radio frequency power supply (506). The coating vacuum chamber (501) is connected to a vacuum supply system (9).

6. The high-vacuum bonding apparatus for compound semiconductor wafers according to claim 5, characterized in that, The alignment vacuum chamber (601) is equipped with a motion mechanism (603), a lower support stage (604), a vision system (605), and a pre-bonding mechanism (606), and is connected to the vacuum supply system (9).

7. The high-vacuum bonding apparatus for compound semiconductor wafers according to claim 6, characterized in that, The bonding vacuum chamber (701) is provided with an upper pressure stage mechanism (703), a lower pressure stage mechanism (704) and a corresponding drive mechanism (705), and the bonding vacuum chamber (701) is connected to the vacuum supply system (9).

8. A high-vacuum bonding apparatus for compound semiconductor wafers according to any one of claims 1-7, characterized in that, The loading unit (2), pretreatment unit (3), activation unit (4), alignment unit (6), bonding unit (7), coating unit (5) and unloading unit (8) are arranged sequentially and at intervals along the circumference of the high vacuum transfer unit (1).

9. A high-vacuum bonding method for compound semiconductor wafers, characterized in that, It is implemented based on the high vacuum bonding apparatus for compound semiconductor wafers as described in claim 8, and includes the following steps: S1: The compound wafers to be processed are placed sequentially into the material box of the feeding unit (2). The vacuum degree of the feeding vacuum chamber (201) reaches 1×10-5Pa. The feeding material box lifting mechanism (203) moves its inner material box to the feeding position in the feeding vacuum chamber (201). S2: Open the first diaphragm valve (202), use the vacuum robot (102) to pick up the first compound wafer from the loading vacuum chamber (201) and transfer it to the pre-alignment unit (13), then close the first diaphragm valve (202). S3: The pre-alignment unit (13) completes the search for the flat edge or Notch of the first compound wafer and performs coarse alignment; S4: Open the second diaphragm valve (302), the vacuum manipulator (102) picks up the first compound wafer in the pre-aligned vacuum chamber (601) and transfers it to the wafer lifting mechanism (304) of the pre-processing vacuum chamber (301), close the second diaphragm valve (302), provide a vacuum environment for the pre-processing vacuum chamber (301) through the vacuum supply system (9), the wafer lifting mechanism (304) descends to bring the first compound wafer closer to the hot plate (303), start the pre-processing process, bake the first compound wafer to remove moisture from its surface, open the second diaphragm valve (302) again, the wafer lifting mechanism (304) rises and drives the first compound wafer away from the hot plate (303), the vacuum manipulator (102) picks up the first compound wafer in the pre-processing vacuum chamber (301) and enters the vacuum operation chamber (101) of the high vacuum transmission unit (1), and close the second diaphragm valve (302) again. S5: Open the third diaphragm valve (402), the vacuum manipulator (102) transfers the first compound wafer to the first wafer carrier stage (403) of the activation vacuum chamber (401), close the third diaphragm valve (402), the vacuum supply system (9) provides a vacuum environment for the activation vacuum chamber (401), the activation unit (4) starts the activation process, the activation power supply (405) and the atomic gun (404) cooperate to generate a plasma beam or atomic beam to irradiate the surface of the first compound wafer, and complete the removal of surface oxides and contaminants of the first compound wafer; open the third diaphragm valve (402) again, the vacuum manipulator (102) picks up the first compound wafer on the first wafer carrier stage (403) and enters the vacuum operation chamber (101) of the high vacuum transmission unit (1), and close the third diaphragm valve (402). S6: Open the fourth partition valve (502), the vacuum robot (102) transfers the first compound wafer to the second wafer carrier (504) of the coating unit (5), close the fourth partition valve (502), the vacuum supply system (9) provides a vacuum environment for the coating vacuum chamber (501), start the coating process, the radio frequency power supply (506) and the ion beam generator (505) excite and generate an ion beam, and irradiate the target material (503), sputtering the target material (503) onto the first compound wafer on the second wafer carrier (504), so that a uniform transition layer film is formed on the surface of the first compound wafer; open the fourth partition valve (502) again, the vacuum robot (102) picks up the first compound wafer on the second wafer carrier (504) and enters the vacuum operation chamber (101) of the high vacuum transmission unit (1), and close the fourth partition valve (502) again; S7: The vacuum manipulator (102) transfers the first compound wafer to the flipping mechanism (1401) of the flipping unit (14). After the first compound wafer is flipped by the flipping mechanism (1401), the vacuum manipulator (102) picks up the first compound wafer and enters the vacuum operation chamber (101) of the high vacuum transmission unit (1). S8: Open the fifth diaphragm valve (602), the vacuum manipulator (102) transfers the first compound wafer to the alignment unit (6), the first compound wafer is adsorbed onto the pre-bonding mechanism (606) in the alignment vacuum chamber (601), wait for the second compound wafer, close the fifth diaphragm valve (602), and the vacuum supply system (9) provides a vacuum environment for the alignment vacuum chamber (601); S9: Repeat S1-S6 to complete the pre-processing of the second compound wafer, open the fifth diaphragm valve (602), and the vacuum robot (102) transfers the second compound wafer to the lower support stage (604) of the alignment vacuum chamber (601). The alignment of the first compound wafer and the second compound wafer is completed through the cooperation of the vision system (605) and the motion mechanism (603). At the same time, the pre-bonding mechanism (606) descends, so that the first compound wafer and the second compound wafer come into contact and press together, completing the pre-bonding of the first compound wafer and the second compound wafer, forming a pre-bonded wafer pair. S10: Open the sixth diaphragm valve (702), and the vacuum robot (102) transfers the pre-bonded wafer pair to the lower pressure stage mechanism (704) of the bonding vacuum chamber (701). Close the sixth diaphragm valve (702), and the vacuum supply system (9) provides a vacuum environment for the alignment vacuum chamber (601). The drive mechanism (705) in the alignment vacuum chamber (601) drives the upper pressure stage mechanism (703) to descend, thereby pressing the pre-bonded wafer pair on the lower pressure stage mechanism (704) to complete the bonding process and obtain the bonded wafer pair. Open the sixth diaphragm valve (702) again, and the vacuum robot (102) picks up the bonded wafer pair and enters the vacuum operation chamber (101) of the high vacuum transmission unit (1). Close the sixth diaphragm valve (702) again. S11: Open the seventh partition valve (802), and the vacuum robot (102) takes the bonding wafer pair out of the alignment vacuum chamber (601) and transfers it to the unloading vacuum chamber (801). The unloading box lift adjusts the height of its box, and the bonding wafer pair is placed in the box of the unloading unit (8). The vacuum robot (102) withdraws from the unloading vacuum chamber (801) and closes the seventh partition valve (802), thus completing one wafer bonding process.

10. The high-vacuum bonding method for compound semiconductor wafers according to claim 9, characterized in that, In S4, the pretreatment temperature in the pretreatment unit (3) is ≤400℃; in S6, the target material (503) in the coating unit (5) is selected from one of silicon target, ceramic target and metal target; in S9, the vision system (605) performs edge alignment or surface marking alignment on the first compound wafer and the second compound wafer; in S10, the maximum bonding pressure of the upper pressure stage mechanism (703) and the lower pressure stage mechanism (704) in the bonding unit (7) is 100Kn and the maximum bonding temperature is 200℃.

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