Wafer bonding wave uniform diffusion control device and method

Abstract

The invention relates to a wafer bonding wave uniform diffusion control device and method. The device comprises a ring-dividing vacuum chuck which comprises a plurality of independent vacuum rings, and each vacuum ring is provided with an independent vacuum channel, an electromagnetic valve and a pressure sensor; the gas auxiliary system is used for injecting gas into the vacuum ring through a gas hole channel; the gap control mechanism comprises a micron-order adjusting mechanism and is used for controlling the gap between the upper wafer and the lower wafer; and the central control unit receives a signal of the pressure sensor and controls the on-off of the electromagnetic valve according to a preset time sequence. According to the device provided by the invention, the bonding wave diffusion uniformity and the yield are greatly improved through ring separation vacuum release and purge gas assistance.

Description

Technical Field

[0001] This invention relates to the field of semiconductor equipment technology, and in particular to a wafer bonding wave uniform diffusion control device and method. Background Technology

[0002] As Moore's Law advances to process nodes below 3nm, wafer direct bonding technology is widely considered a crucial technological approach supporting 3D chip integration, and has recently become a hot topic of interest for leading semiconductor companies and research institutions both domestically and internationally. The wafer bonding process typically starts from a single point and gradually diffuses across the entire wafer surface, often referred to as the "bonding wave" diffusion process. Influenced by factors such as wafer surface coating materials, circuit design, activation methods, and parameters, the bonding wave diffusion time can range from several seconds to tens of seconds. The propagation morphology of the bonding wave significantly affects the precision and quality of the bonding (e.g., residual stress distribution, wafer morphology, bond strength, etc.).

[0003] Bonding wave uniform diffusion technology has wide applications in semiconductor manufacturing and high-end packaging. Its core value lies in improving device performance and reliability by precisely controlling energy propagation at the bonding interface. Currently, this technology has evolved from a simple process step into a common fundamental technology supporting advanced semiconductor manufacturing and high-end device integration. Its progress will directly drive the continuation of Moore's Law and the implementation of emerging applications.

[0004] In high-precision bonding equipment, a related patent (CN110289222A) has proposed a scheme to monitor bonding waves by arranging light emitting and receiving devices on the upper chuck and observing the morphological changes of the upper wafer before and after bonding.

[0005] Patent (CN119153345A) proposes a scheme where the upper and lower chucks each have multiple independently adjustable adsorption regions; and a return loss feedback system is used to obtain the deformation signal of the lower wafer caused by the bonding wave. CN119153345A involves ring-separated adsorption, but the ring-separated adsorption only serves as a static support structure, achieving coarse adjustment of the wafer surface shape through independently adjustable adsorption regions, without involving dynamic control of the bonding wave; and it only fixes the wafer through adsorption force, without involving the dynamic control of the bonding wave.

[0006] The shortcomings of the existing solution are as follows:

[0007] 1. Because the wafer itself has a crystalline phase, the deformation at different positions of the wafer is inconsistent when the pin is pressed down, and the signal changes detected by the photosensitive device cannot reflect the actual position of the bonding wave.

[0008] 2. Optical sensors occupy a large space and require complex control and wiring layouts, thus limiting the number of sensors that can be placed on the same chuck. The highly discrete data points make accurate fitting of the bonded wave propagation morphology extremely difficult.

[0009] 3. The chuck is set with bumps to place the optical fiber, and the top of the optical fiber is flush with the bumps. During the bonding process, there is a certain amount of contact and friction between the two wafers. The chuck and wafer may cause electromagnetic interference or attenuation to microwave / optical signals, which requires precise shielding and calibration. This can easily lead to signal attenuation and failure.

[0010] 4. The chuck used in the hybrid bonding process is a deformation chuck, which has a significant impact on adjusting the wafer's surface shape. During the deformation of the chuck, the fiber signal experiences deviations and may even fail to be received.

[0011] 5. Maintaining a constant nanometer-scale gap between the waveguide end and the wafer surface is almost impossible; any change in the gap will result in a signal drift much greater than that caused by the bonding waveform change.

[0012] 6. Anti-interference waveguide systems will significantly increase equipment costs, making them expensive and difficult to maintain. Summary of the Invention

[0013] To address some or all of the problems in the prior art, the present invention provides a wafer bonding wave uniform diffusion control device, the device comprising:

[0014] A split-ring vacuum chuck comprises multiple independent vacuum rings, each of which is equipped with an independent vacuum channel, solenoid valve, and pressure sensor.

[0015] A gas-assisted system that injects gas into the vacuum ring through gas channels; and

[0016] The central control unit receives pressure sensor signals and controls the opening and closing of the solenoid valves according to a preset timing sequence.

[0017] Furthermore, the wafer bonding wave uniform diffusion control device further includes:

[0018] The gap control mechanism includes a micron-level adjustment mechanism for controlling the gap between the upper and lower wafers.

[0019] Furthermore, the diameter of the vacuum ring ranges from 7 mm to 293 mm; and / or

[0020] The adsorption force of the vacuum ring ranges from 10 kg to 60 kg; and / or

[0021] The response time of the solenoid valve is <10ms; and / or

[0022] The response time of the pressure sensor is <5ms; and / or

[0023] The gap between the upper and lower wafers ranges from 10μm to 50μm.

[0024] Furthermore, the gas injected into the vacuum ring is a purge gas with a pressure range of 0.17 MPa to 0.41 MPa; and / or

[0025] The pressure of the purge gas is controlled by an electronic regulator; and / or

[0026] The purge gas is nitrogen with a purity greater than 99%.

[0027] Furthermore, the micrometer-level adjustment mechanism includes an electrically driven microprobe; and / or

[0028] The gap control mechanism also includes an O-ring elastic support structure.

[0029] The present invention also provides a wafer bonding wave uniform diffusion control method based on the aforementioned wafer bonding wave uniform diffusion control device, the method comprising the following steps:

[0030] Adjust the gap between the upper and lower wafers to the set interval range;

[0031] The upper chuck pin is activated, pressing down on the center of the upper wafer, causing the center of the upper wafer to bulge, thus allowing the bonding wave to diffuse outward from the wafer center; and

[0032] Vacuum rings are released sequentially in order of increasing radius.

[0033] Furthermore, the wafer bonding wave uniform diffusion control method further includes:

[0034] Pressure sensors are used to monitor the adsorption force of each vacuum ring in real time. When the decrease in the adsorption force of a vacuum ring exceeds a set threshold, purge gas is injected into the adjacent vacuum ring.

[0035] When the bonding wave reaches the outermost ring of the vacuum ring, the full-ring purge gas homogenization process is initiated.

[0036] Furthermore, the set interval range is 10μm-50μm; and / or

[0037] The release interval of the vacuum ring is 50ms-200ms.

[0038] Furthermore, the gap adjustment is achieved through the linkage between the O-ring elastic support structure and the electric microprobe; and / or

[0039] The coordinated operation of the vacuum ring release and purge pressurization is dynamically adjusted by the central control unit based on real-time adsorption force feedback.

[0040] Furthermore, when the wafer gap is ≥50μm, forced pressurization is applied through a purge gas pressure of 0.24MPa throughout the ring; and / or

[0041] When the wafer thickness is ≥500μm, the release interval is 100ms-200ms; and / or

[0042] The pressure of the purge gas is selected according to the region of the vacuum ring: 0.41 MPa in the inner ring, 0.38 MPa in the middle ring, and 0.20 MPa in the outer ring.

[0043] Further, the set threshold is 66.67%; and / or

[0044] After the bonding wave reaches the outermost ring, a purge pressure of 0.20 MPa is applied to the entire ring for 1 second to eliminate residual stress at the interface.

[0045] The present invention also provides a wafer bonding apparatus, including the aforementioned bonding wave uniform diffusion control device.

[0046] The present invention also provides a semiconductor device manufacturing method, which uses the wafer bonding wave control method to realize the connection of the wafer bonding interface.

[0047] The technical solution provided by this invention has the following advantages:

[0048] 1. The wafer bonding wave uniform diffusion control device proposed in this invention does not require an optical or acoustic monitoring system, but only adopts mechanical gap control and solenoid valve array, reducing hardware costs by 60%; the control algorithm is based on timing logic and threshold judgment, requiring no machine learning model, and the software implementation is simple.

[0049] 2. The wafer bonding wave uniform diffusion control device proposed in this invention, through the use of split-loop vacuum release and purge gas assistance, significantly improves the bonding wave diffusion uniformity and yield. This structural design avoids the errors and correction time caused by the dual closed loop of sensing and control, thereby improving production output and efficiency.

[0050] 3. The wafer bonding wave uniform diffusion control device proposed in this invention is applicable to various materials such as silicon, glass, and compound semiconductors. It adapts to the interface characteristics of different materials by adjusting the vacuum ring suction force and purge gas pressure.

[0051] 4. The wafer bonding wave uniform diffusion control device proposed in this invention can achieve forced uniform pressurization by full-ring purge (0.24MPa) when the wafer gap increases to 50μm (van der Waals force weakens), thus compensating for the gap limitation of traditional van der Waals force bonding. Attached Figure Description

[0052] To further illustrate the above and other advantages and features of the various embodiments of the present invention, a more specific description of the various embodiments of the present invention will be presented with reference to the accompanying drawings. It is to be understood that these drawings depict only typical embodiments of the invention and are therefore not intended to limit its scope. In the drawings, identical or corresponding parts will be indicated by identical or similar reference numerals for clarity.

[0053] Figure 1 A schematic diagram of the wafer bonding wave uniform diffusion control device according to an embodiment of the present invention is shown;

[0054] Figure 2 A top view schematic diagram of a split-ring vacuum chuck according to an embodiment of the present invention is shown;

[0055] Figure 3 This diagram illustrates the electrical control principle of a wafer bonding wave uniform diffusion control device according to an embodiment of the present invention.

[0056] Figure 4 A schematic flowchart of a wafer bonding wave uniform diffusion control method according to an embodiment of the present invention is shown.

[0057] Figure 5 A schematic diagram of the mechanical equilibrium of the bonding wavefront according to an embodiment of the present invention is shown;

[0058] Figures 6a-6b This diagram illustrates a simulation process for wafer bonding with a small wafer gap according to an embodiment of the present invention; and

[0059] Figures 7a-7d A schematic diagram of a simulation process for wafer bonding when the wafer gap is large, according to an embodiment of the present invention, is shown. Detailed Implementation

[0060] In the following description, the invention is described with reference to various embodiments. However, those skilled in the art will recognize that the embodiments may be implemented without one or more specific details or with other alternatives and / or additional means or components. In other instances, well-known structures or operations are not shown or described in detail so as not to obscure the inventive points of the invention. Similarly, for illustrative purposes, specific numbers and configurations are set forth to provide a comprehensive understanding of embodiments of the invention. However, the invention is not limited to these specific details.

[0061] In this specification, references to "an embodiment" or "this embodiment" mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the invention. The phrase "in one embodiment" appearing throughout this specification does not necessarily refer to the same embodiment in all instances.

[0062] It should be noted that the embodiments of the present invention describe the device steps in a specific order; however, this is only for illustrating the specific embodiment and not for limiting the order of the steps. On the contrary, in different embodiments of the present invention, the order of the steps can be adjusted according to actual needs.

[0063] Uniform diffusion of the bond wave during wafer bonding is a core indicator of high-quality bonding, bringing benefits across multiple dimensions, including electrical performance, mechanical reliability, thermal management, and mass production efficiency. Non-uniform diffusion leads to residual stress at the interface (such as high-stress areas at the edges), causing wafer warping or cracking. Uniform diffusion ensures atomic-level tight contact at the bonding interface, reducing microvoids and impurity-rich areas. Microvoids are the starting point of delamination, and uniform diffusion reduces the void ratio to <0.1%. Hybrid bonding requires synchronous metal diffusion and dielectric layer fusion, making uniform diffusion of the bond wave crucial. Uniform diffusion of the bond wave is not merely an "optional action" for process optimization, but an essential path to achieving highly reliable and high-performance chips.

[0064] This application provides a wafer bonding wave uniform diffusion control device. The segmented vacuum design serves as a dynamic driving source. Through sequential release of vacuum rings and the assistance of purge gas, a mechanical gradient is formed to propagate the bonding wave, representing an innovation in actively controlling the bonding wave propagation path. This application utilizes a pressure sensor to provide real-time feedback on changes in adsorption force, combined with purge gas pressure compensation, to generate a bonding wave driving force, achieving active adjustment of mechanical balance.

[0065] Figure 1 A schematic diagram of a wafer bonding wave uniform diffusion control device according to an embodiment of the present invention is shown. Figure 2 A top view schematic diagram of a split-ring vacuum chuck according to an embodiment of the present invention is shown. Figure 3 A schematic diagram of the electrical control principle of a wafer bonding wave uniform diffusion control device according to an embodiment of the present invention is shown below. Figures 1-3 This invention provides a wafer bonding wave uniform diffusion control device. Figure 1 As shown, a wafer bonding wave uniform diffusion control device includes a split-ring vacuum chuck, a gas-assisted system, a gap control mechanism, and a central control unit.

[0066] like Figure 2 As shown, the segmented vacuum chuck comprises multiple independent vacuum rings 201 and purge rings 202. In one embodiment of the invention, the purge rings 202 are used to inject purge gas, and the vacuum rings 201 and purge rings 202 are arranged at intervals. Each vacuum ring is equipped with an independent vacuum channel, a solenoid valve, and a pressure sensor.

[0067] In one embodiment of the present invention, the diameter of the vacuum ring can be in the range of 7mm-293mm; and / or the adsorption force of the vacuum ring can be in the range of 10kg-60kg.

[0068] In one embodiment of the present invention, the vacuum rings are arranged in an array design, comprising an inner ring, a middle ring, and an outer ring. For example, the vacuum rings may include SV1 to SV7; the inner rings (e.g., from SV1 to SV2) have a diameter of 7 mm and an area of ​​7.065 mm². 2 Designed with a suction power of 10kg for center positioning; middle ring (e.g., from SV3 to SV5): diameter 60mm, area 28.26mm². 2 Combined with a purge pressure of 0.38 MPa, mid-range diffusion control is achieved; outer ring (e.g., from SV6 to SV7): diameter 290 mm, area 660.185 mm². 2 Edge bonding is achieved using a 0.20 MPa pressure aerator. It's worth noting that the pressure uniformity design employs the isobaric adsorption principle, meaning the adsorption force per unit area is consistent. F = P * S, where: F is the adsorption force (kg), P is the vacuum level (MPa), and S is the ring area (mm²). 2 Example parameters: Inner ring (7mm) 2 Vacuum degree: 0.14 MPa; Adsorption force: 10 kg (0.14 × 7 ≈ 10); Outer ring (660 mm) 2 Vacuum degree 0.09MPa, adsorption force 60kg (0.09×660≈60), the vacuum degree of each ring can be independently adjusted by solenoid valve to achieve the adaptation of adsorption force under different areas.

[0069] It should be noted that the diameter of the vacuum ring is not limited to the range of 7mm-293mm; and / or the area of ​​the vacuum ring is not limited to 7.065mm². 2 -660.185mm 2 The range; and / or the adsorption force range of the vacuum ring is not limited to 10kg-60kg; the specific range can be determined according to the specific situation of the vacuum ring.

[0070] In one embodiment of the present invention, multiple 3-port solenoid valves are used, which are evenly distributed around the chuck. Each solenoid valve controls the vacuum / atmosphere / purge state of one vacuum ring, with a response time of <10ms.

[0071] In one embodiment of the present invention, the pressure sensor has an accuracy of ±0.2%FS and a response time of <5ms (the measured value can be 3.2ms), meeting the 50ms level control cycle (the response time accounts for only 6.4% of the control cycle). Figure 3As shown, the purge ring 4 and vacuum ring 5 are spaced apart, the wafer 3 is on the left, the vacuum control valve 7 includes a solenoid valve and a pressure sensor, the vacuum control system 8 is used to control the opening and closing of the vacuum control valve 7, and the pin pressing control system 9 is used to control the pressing down of the pin 6.

[0072] like Figure 3 As shown, the gas-assisted system injects gas into the vacuum ring through a gas channel; the gas can be purge gas. The gas-assisted system is the purge control system 11, which controls the opening and closing of the purge control valve 10, injecting purge gas into the purge ring 4. In one embodiment of the invention, the pressure of the purge gas injected into the vacuum ring is controllable, ranging from 0.17 MPa to 0.41 MPa; and / or the pressure of the purge gas is controlled by an electronic regulator, with a maximum flow rate of 6 L / min; and / or the purge gas is nitrogen with a purity greater than 99%.

[0073] The gap control mechanism includes a micrometer-level adjustment mechanism for controlling the gap between the upper and lower wafers within the range of 10μm-50μm, ensuring the effective action of van der Waals forces. In one embodiment of the invention, the micrometer-level adjustment mechanism includes an electric microprobe; and / or the gap control mechanism further includes an O-ring elastic support structure. In one embodiment of the invention, the electric microprobe has a measurement accuracy of ±0.5μm, a repeatability of ±0.3μm, and a response time of <30ms (at a stroke of 20μm); the O-ring elastic support structure can be made of fluororubber with a coefficient of thermal expansion of 2.5×10⁻⁶. -4 / ℃, thermal deformation <1μm at 100℃ process temperature; the electric micro probe collects gap data every 50ms and adjusts the O-ring compression amount through PID algorithm to counteract thermal deformation.

[0074] The central control unit receives pressure sensor signals and controls the opening and closing of the solenoid valve and the pressure of the purging gas according to a preset timing sequence. The control logic of the central control unit is as follows: the pressure sensor sampling frequency is 200Hz (period 5ms), and the central control unit adopts an interrupt triggering mechanism. When the adsorption force changes beyond the threshold, the purging solenoid valve is activated within 10ms, with a total delay of <15ms, which is much less than the 50ms control interval.

[0075] The accuracy of purge gas flow control and the stability of gas pressure satisfy the formula.

[0076]

[0077] Where ΔP is the pressure fluctuation (MPa), and μ is the gas viscosity (N·s / m³). 2 L is the gas path length (m), and ΔQ is the flow rate fluctuation (m).3 / s), A is the cross-sectional area of ​​the gas path (m²) 2 ), where ρ is the gas density (kg / m³) 3 P0 is the reference pressure (MPa).

[0078] The measured data is as follows: when the flow control accuracy is ±0.1 L / min (i.e., ΔQ = 1.67 × 10⁻⁶ m³), ​​the flow rate is within the range of ±0.1 L / min. 3 With a gas path length of 0.5m and a pipe diameter of 2mm, the gas pressure stability is ±0.3% (0.17-0.41MPa range). The gas pressure stability is good with minimal fluctuations.

[0079] It's worth noting that the purging gas is generally located on the back side of the bonded wafer and does not contact the bonding interface. The purging gas used is 99.999% high-purity nitrogen (melting point < -70℃, particle size < 0.1μm); the filtration system includes a 0.01μm polytetrafluoroethylene (PTFE) filter connected in series in the gas path to remove particulate impurities; and the sealing design uses VCR metal seals at the gas path interfaces to prevent the release of contaminating gases from rubber components. Inert gases (such as nitrogen) do not react with semiconductor materials at the bonding temperature (< 400℃), and the gas flow rate (6L / min) creates positive pressure purging, which can remove trace contaminants (such as oxides) remaining at the interface, improving bonding quality.

[0080] This invention also provides a wafer bonding wave uniform diffusion control method based on the aforementioned wafer bonding wave uniform diffusion control device, the process of which is as follows: Figure 4 As shown, the method includes the following steps:

[0081] First, the gap between the upper and lower wafers is adjusted to a set interval range. In one embodiment of the invention, the set interval range can be 10μm-50μm. This step is the initial gap setting. Preferably, the gap between the upper and lower wafers can be adjusted to 20μm, at which point the van der Waals force is relatively strong (on the order of 10^-5N), providing a basic driving force for bonding wave diffusion. In one embodiment of the invention, gap control is achieved through the linkage of an O-ring elastic support structure and an electric microprobe, realizing mechanical locking of the 20μm gap, eliminating the need for complex displacement sensors, and reducing costs by approximately 40%. It is worth noting that the 20μm gap is stabilized through a triple stabilization mechanism: material selection, the O-ring is made of low-expansion fluororubber (Shore hardness of about 70A), with an expansion of <1.5μm at 100℃; structural design, the O-ring is embedded in the chuck groove (depth of about 25μm), with a compression of 5μm, forming an interference fit to offset processing errors; dynamic compensation, the electric micro probe scans the gap every 100ms, and when the offset is >2μm, it is corrected in real time by a piezoelectric ceramic fine-tuning mechanism (accuracy of 0.1μm).

[0082] It is worth noting that when the wafer gap increases to 50μm (van der Waals forces weaken), forced uniform pressurization can be achieved through full-ring purge (0.24MPa) to compensate for the gap limitation of traditional van der Waals bonding.

[0083] Next, the pins of the upper chuck are activated, pressing down on the center of the upper wafer, causing the center of the upper wafer to bulge, allowing the bonding wave to diffuse outward from the wafer center. Through vacuum adsorption in the central region, the wafer center makes initial contact, allowing the bonding wave to diffuse outward from the wafer center.

[0084] Next, vacuum rings are released sequentially in ascending order of radius. In one embodiment of the invention, the release interval of the vacuum rings can be 50ms-200ms, with 1-2 vacuum rings released each time. The dynamic adjustment mechanism of the release interval is as follows: the adsorption force decay rate is monitored by a pressure sensor. When the decay rate is <0.5kg / ms, the interval is automatically extended to 150ms to adapt to wafers of different thicknesses. For general wafers, the release interval can be 100ms-200ms; when the wafer thickness is ≥500μm, the release interval can be 100ms-200ms to avoid bonding wave propagation lag. Physical pressurization is performed on the vacuum rings corresponding to the bonding wave diffusion lag region (the gas pressure can be 0.17MPa-0.41MPa) to compensate for insufficient local van der Waals forces. It should be noted that the pressurization method can also be a physical pressurization method other than purge.

[0085] COMSOL simulations show that a 20-vacuum-ring design can be used for 12-inch wafers (300mm in diameter). This design can control the radial pressure gradient of the 12-inch wafer within ±5%. When the number of vacuum rings is less than 10, the edge pressure unevenness exceeds 15%. When the number of vacuum rings is greater than 30, the chuck processing complexity increases, the cost increases by about 30%, and the uniformity improvement is only 2%. Another suitable solution for 12-inch wafers is to increase the number of vacuum rings to 28 and reduce the outer ring width to 5mm while maintaining radial resolution. The outer rings can use stepped gas pressure control, that is, the purge pressure of the outermost ring is 0.05MPa higher than that of the inner ring, to offset the attenuation of edge adhesion force (experiments have shown that this can improve edge bonding strength by 12%).

[0086] Next, pressure sensors are used to monitor the adsorption force of each vacuum ring in real time. When the decrease in the adsorption force of a vacuum ring exceeds a set threshold, purge gas is injected into the adjacent vacuum ring. When the decrease in the adsorption force of a vacuum ring exceeds the set threshold, it is determined that a bonding wave has reached the region of that vacuum ring, and purge gas is injected into the adjacent vacuum ring. In one embodiment of the present invention, the set threshold can be 66.67%.

[0087] In one embodiment of the invention, another approach can be used to monitor bond wave diffusion: capacitive or pressure sensors are arranged on the chuck. Because the patterned wafer is affected by the internal wiring, to understand and control this situation, the sensors cannot simply be arranged in a crosshair pattern; multiple sensors need to be distributed at a certain angle (22.5°) to monitor and adjust the diffusion in each area. This approach can use 16 x 4 = 64 sensors to accurately locate the diffusion problem and adjust it through hardware matching.

[0088] Finally, when the bonding wave reaches the outermost ring of the vacuum ring, the full-ring purge gas homogenization process is initiated.

[0089] Figure 5 A schematic diagram of the mechanical equilibrium of the bonding wavefront according to an embodiment of the present invention is shown. The forces acting on the bonding wavefront satisfy: Fvacuum release + Fpurge = Fvan der Waals + Finterfacial resistance. Wherein: Fvacuum release is the pressure gradient generated by the release of the vacuum ring, Fpurge is the gas-assisted pressure, Fvan der Waals is the van der Waals force, and Finterfacial resistance is the atomic diffusion resistance.

[0090] In one embodiment of the invention, the purge pressure is selected according to the regional location of the vacuum ring: 0.41 MPa in the inner ring region, 0.38 MPa in the middle ring region, and 0.20 MPa in the outer ring region. In another embodiment of the invention, after the bonding wave reaches the outermost ring, a purge pressure of 0.20 MPa is applied to the entire ring for 1 second to eliminate residual stress at the interface.

[0091] In one embodiment of the present invention, the coordinated operation of vacuum ring release and purge pressurization is dynamically adjusted by the central control unit based on real-time adsorption force feedback.

[0092] Figures 6a-6b This diagram illustrates a simulation process for wafer bonding with a small wafer gap, according to an embodiment of the present invention. Figures 7a-7d This diagram illustrates a simulation process for wafer bonding when the wafer gap is large, according to one embodiment of the present invention. Figures 6a-6b and Figures 7a-7d In this configuration, purge ring 4 and vacuum ring 5 are located on the upper wafer 3, while the lower wafer 12 is supported by the lower chuck 13. It should be noted that a smaller gap is typically <30µm, while a gap >30µm is considered larger. Figures 6a-6b As shown, when the wafer gap is small, the vacuum ring is gradually released to achieve uniform diffusion of the bonding wave. Figures 7a-7d As shown, when the wafer gap is large, there is an anomaly during the gradual release of the vacuum ring. Figure 7c and Figure 7dThe red area indicates a situation where bonding wave diffusion is uneven. By using purge gas to forcibly diffuse the bonding wave diffusion length in the poorly diffused area, uniform diffusion is achieved, thereby improving the bonding yield and reducing the residual stress at the interface.

[0093] Taking a 12-inch wafer as an example, the wafer bonding wave uniform diffusion control method provided by this invention is explained. The 12-inch wafer is divided into 20 vacuum rings. RG1-RG7 are the first 7 of the 20 vacuum rings, arranged in ascending order of radius: RG1, inner diameter 7mm, outer diameter 10mm; RG2, outer diameter 15mm; ...; RG7, outer diameter 60mm (middle ring boundary). The remaining RG8-RG20 are the edge regions. The control logic of the wafer bonding wave uniform diffusion control method is that RG1-RG7 are used for the initial propagation stage of the bonding wave (from the center to the 60mm radius), and RG8-RG20 subsequently control the edge regions, forming a timing control chain of center initiation - mid-range advancement - edge termination.

[0094] In actual designs, there are RG1-RG20. The following is a simplified description of the diffusion process of RG1-RG7. The process of RG8-RG20 is similar and will not be described in detail here.

[0095] The wafer bonding wave uniform diffusion control method provided by this invention is as follows: After the upper and lower wafers are aligned, the alignment mark (10-30μm) is confirmed by an IR camera, and the gap is adjusted to 20μm; vacuum adsorption (20kg suction force) is applied to the central φ30mm area for 500ms to form the central bonding start point; one vacuum ring is released every 100ms in the order of RG1→RG2→RG3, while RG2 is purged at 0.41MPa to push the bonding wave outward; when the pressure sensor detects that the adsorption force of RG4 drops from 30kg to 10kg (at which point the bonding wave is determined to have arrived), RG5 is activated with 0.38MPa purge assistance; after the bonding wave reaches RG7, 0.20MPa nitrogen purge is introduced into the entire ring and maintained for 1s to complete homogenization.

[0096] This invention proposes a wafer bonding wave uniform diffusion control device that eliminates the need for optical or acoustic monitoring systems, employing only mechanical gap control and a solenoid valve array, reducing hardware costs by 60%. The control algorithm, based on timing logic and threshold judgment, requires no machine learning model, simplifying software implementation. This wafer bonding wave uniform diffusion control device, through a combination of vacuum release and purge gas assistance, significantly improves bonding wave diffusion uniformity and yield. This structural design avoids errors and correction time associated with dual closed-loop sensing and control, increasing production output and efficiency. This wafer bonding wave uniform diffusion control device is applicable to various materials such as silicon, glass, and compound semiconductors, adapting to different material interface characteristics by adjusting the vacuum ring suction and purge gas pressure.

[0097] The present invention also provides a wafer bonding apparatus, including the aforementioned bonding wave uniform diffusion control device.

[0098] The present invention also provides a semiconductor device manufacturing method, which uses the wafer bonding wave control method to realize the connection of the wafer bonding interface.

[0099] Although various embodiments of the present invention have been described above, it should be understood that they are presented by way of example only and not as limitations. It will be apparent to those skilled in the art that various combinations, modifications, and alterations can be made without departing from the spirit and scope of the invention. Therefore, the breadth and scope of the invention disclosed herein should not be limited by the exemplary embodiments disclosed above, but should be defined according to the technical solutions of the invention and their equivalents.

Claims

1. A wafer bonding wave uniform diffusion control device, characterized in that, include: A split-ring vacuum chuck comprises multiple independent vacuum rings, each of which is equipped with an independent vacuum channel, solenoid valve, and pressure sensor. A gas-assisted system that injects gas into the vacuum ring through gas channels; and The central control unit receives pressure sensor signals and controls the opening and closing of the solenoid valves according to a preset timing sequence.

2. The wafer bonding wave uniform diffusion control device according to claim 1, characterized in that, Also includes: The gap control mechanism includes a micron-level adjustment mechanism for controlling the gap between the upper and lower wafers.

3. The wafer bonding wave uniform diffusion control device according to claim 1 or 2, characterized in that, The diameter of the vacuum ring ranges from 7mm to 293mm; and / or The adsorption force of the vacuum ring ranges from 10 kg to 60 kg; and / or The response time of the solenoid valve is <10ms; and / or The response time of the pressure sensor is <5ms; and / or The gap between the upper and lower wafers ranges from 10μm to 50μm.

4. The wafer bonding wave uniform diffusion control device according to claim 1, characterized in that, The gas injected into the vacuum ring is a purge gas, and the pressure range of the purge gas is 0.17 MPa-0.41 MPa; and / or The pressure of the purge gas is controlled by an electronic regulator; and / or The purge gas is nitrogen with a purity greater than 99%.

5. The wafer bonding wave uniform diffusion control device according to claim 1 or 2, characterized in that... , The micron-level adjustment mechanism includes an electrically driven microprobe; and / or The gap control mechanism also includes an O-ring elastic support structure.

6. A wafer bonding wave uniform diffusion control method based on the wafer bonding wave uniform diffusion control device according to any one of claims 1-5, characterized in that, Includes the following steps: Adjust the gap between the upper and lower wafers to the set interval range; The upper chuck pin is activated, pressing down on the center of the upper wafer, causing the center of the upper wafer to bulge, thus allowing the bonding wave to diffuse outward from the wafer center; and Vacuum rings are released sequentially in order of increasing radius.

7. The wafer bonding wave uniform diffusion control method according to claim 6, characterized in that, Also includes: Pressure sensors are used to monitor the adsorption force of each vacuum ring in real time. When the decrease in the adsorption force of a vacuum ring exceeds a set threshold, purge gas is injected into the adjacent vacuum ring. When the bonding wave reaches the outermost ring of the vacuum ring, the full-ring purge gas homogenization process is initiated.

8. The wafer bonding wave uniform diffusion control method according to claim 6, characterized in that, The set interval range is 10μm-50μm; and / or The release interval of the vacuum ring is 50ms-200ms.

9. The wafer bonding wave uniform diffusion control method according to claim 6 or 7, characterized in that, The gap adjustment is achieved through the linkage between the O-ring elastic support structure and the electric microprobe; and / or The coordinated operation of the vacuum ring release and purge pressurization is dynamically adjusted by the central control unit based on real-time adsorption force feedback.

10. The wafer bonding wave uniform diffusion control method according to claim 6 or 7, characterized in that, When the wafer gap is ≥50μm, forced pressurization is applied through a purge gas pressure of 0.24MPa throughout the ring; and / or When the wafer thickness is ≥500μm, the release interval is 100ms-200ms; and / or The pressure of the purge gas is selected according to the region of the vacuum ring: 0.41 MPa in the inner ring, 0.38 MPa in the middle ring, and 0.20 MPa in the outer ring.

11. The wafer bonding wave uniform diffusion control method according to claim 7, characterized in that, The set threshold is 66.67%; and / or After the bonding wave reaches the outermost ring, a purge pressure of 0.20 MPa is applied to the entire ring for 1 second to eliminate residual stress at the interface.

12. A wafer bonding apparatus, characterized in that, Includes a bonding wave uniform diffusion control device according to any one of claims 1-5.

13. A method for manufacturing a semiconductor device, characterized in that, The wafer bonding interface connection is achieved using the wafer bonding wave control method according to any one of claims 6-11.

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