An optical imaging alignment system for flip chip precision bonding

Abstract

The present application relates to a kind of optical imaging alignment system for chip precision flip welding, the optical imaging alignment system includes substrate heating self-balancing fixing device, substrate illumination device, wafer self-balancing fixing device, wafer illumination device, half-mirror, full reflection plane mirror and imaging device, substrate heating self-balancing fixing device, half-mirror and wafer self-balancing fixing device are sequentially spaced along first optical axis, half-mirror is obliquely intersected with first optical axis, substrate fixed surface and wafer fixed surface are all towards half-mirror;Full reflection plane mirror, half-mirror and imaging device are sequentially spaced along second optical axis, first optical axis and second optical axis intersect, the reflection surface of full reflection plane mirror and the light receiving end of imaging device are towards half-mirror.The above-mentioned optical imaging alignment system realizes the alignment of wafer and substrate by imaging, it is convenient to realize precision alignment, and optical structure is simple, low in cost, easy to realize.

Description

Technical Field

[0001] This invention relates to the field of photonic optoelectronic device design technology, and in particular to an optical imaging alignment system for precision flip-chip bonding. Background Technology

[0002] In recent years, with the in-depth development of silicon-based photonics, passive devices such as optical switches and optical waveguides have been successfully integrated on SOI platforms. However, research on core devices like lasers on Si has progressed slowly, mainly because Si is an indirect bandgap semiconductor with low luminous efficiency. Currently, a relatively mature method is to heterogeneously integrate III-V group materials with Si through bonding, enabling III-V light sources to output from Si waveguides. Hybrid integration of III-V (such as GaAs, InP, etc.) group materials and silicon is currently considered the most promising photonic or optoelectronic chip technology suitable for high-density integration. Typically, SOI materials (Si / SiO2 / Si substrate) with waveguide structures are bonded to III-V epitaxial materials using organic materials or bonding methods. The III-V substrate is then removed, and photonic or optoelectronic devices and optical paths are fabricated. Light waves are coupled into the underlying SOI waveguide through evanescent field coupling, and electrical injection is performed using coplanar electrodes on the III-V material layer. Bonding technology is crucial in this process. Several issues arise for surface light sources formed through wafer bonding. First, most CMOS factories do not allow the processing of III-V materials for fear of introducing contamination. Second, bonding the materials before making the laser results in a relatively low yield. Third, III-V wafers have a relatively small diameter while silicon-based materials have a relatively large diameter, so bonding the wafers before processing results in significant waste.

[0003] A feasible approach is to first fabricate III-V group laser dies or arrays using conventional semiconductor processes, select suitable ones, and then integrate them using various coupling methods. However, achieving high coupling efficiency is extremely difficult. The challenge lies in the coupling of active and passive waveguide devices. Typical coupling waveguides are wedge-shaped and anti-wedge-shaped waveguide structures, requiring sub-micron or even deep sub-micron level lateral alignment accuracy between the laser unit and the waveguide center. A commonly used method is flip-chip bonding. Flip-chip bonding equipment uses a pick-and-place tool to hold the wafer, then uses complex imaging and alignment to locate the target position and achieve bonding. Typically, the pick-and-place tool's end face must be perfectly parallel to the target wafer plane; otherwise, weak bonding and low coupling efficiency will occur. Summary of the Invention

[0004] The purpose of this invention is to provide an optical imaging alignment system for precision flip-chip bonding, which achieves alignment between the wafer and the substrate while being low-cost, simple in optical system, and easy to implement.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] An optical imaging alignment system for precision flip-chip bonding is used to align a substrate and a wafer, wherein alignment marks are respectively provided on the substrate and the wafer, and the system includes a substrate heating self-balancing fixing device, a substrate illumination device, a wafer self-balancing fixing device, a wafer illumination device, a semi-transparent and semi-reflective plane mirror, a fully reflective plane mirror, and an imaging device.

[0007] The substrate heating self-balancing fixing device, the semi-transparent and semi-reflective plane mirror, and the wafer self-balancing fixing device are arranged sequentially at intervals along the first optical axis. The semi-transparent and semi-reflective plane mirror intersects the first optical axis at an angle. The substrate heating self-balancing fixing device has a substrate fixing surface for fixing the substrate, and the wafer self-balancing fixing device has a wafer fixing surface for fixing the wafer. Both the substrate fixing surface and the wafer fixing surface face the semi-transparent and semi-reflective plane mirror. The substrate heating self-balancing fixing device and the wafer self-balancing fixing device are used to make the substrate and the wafer parallel to each other. The substrate illumination device is used to illuminate the substrate on the substrate heating self-balancing fixing device, and the wafer illumination device is used to illuminate the wafer on the wafer self-balancing fixing device.

[0008] The total reflection plane mirror, the semi-transparent and semi-reflective plane mirror, and the imaging device are arranged sequentially at intervals along the second optical axis. The first optical axis intersects the second optical axis, and the reflecting surface of the total reflection plane mirror and the light receiving end of the imaging device face the semi-transparent and semi-reflective plane mirror.

[0009] In one embodiment of this application, the substrate heating self-balancing fixing device includes:

[0010] A first fixed base, wherein the first fixed base is provided with a first spherical slot;

[0011] The first suction cup has a first spherical protrusion on one side surface. The first spherical slot engages with the first spherical protrusion so that the first fixed base and the first suction cup can rotate relative to each other. One of the mating surfaces of the first spherical slot and the first spherical protrusion is a concave spherical surface and the other is a convex spherical surface. The first suction cup has a plurality of first air holes on the side surface away from the first spherical protrusion.

[0012] A heating device, wherein the heating device is disposed within the first suction cup;

[0013] The first negative pressure device is connected to each of the first air holes.

[0014] In one embodiment of this application, the heating device includes a thermocouple, a resistance wire, and a temperature controller. The resistance wire is wound inside the first suction cup. The thermocouple is used to detect the temperature of the first suction cup. The temperature controller is used to control the operating state of the circuit containing the resistance wire based on the detection value of the thermocouple.

[0015] In one embodiment of this application, the wafer self-balancing fixing device includes:

[0016] The second fixed base is provided with a second spherical slot.

[0017] The second suction cup has a second spherical protrusion on one side surface. The second spherical groove engages with the second spherical protrusion so that the second fixed base and the second suction cup can rotate relative to each other. One of the mating surfaces of the second spherical groove and the second spherical protrusion is a concave spherical surface and the other is a convex spherical surface. The second suction cup has a plurality of second air holes on the side surface away from the second spherical protrusion.

[0018] The second negative pressure device is connected to each of the second air holes.

[0019] In one embodiment of this application, an optical housing is further included. The semi-transparent and semi-reflective plane mirror and the total reflection plane mirror are disposed inside the optical housing. A first entrance hole and a second entrance hole are respectively provided on two housing walls that are arranged opposite to each other along the first optical axis. The substrate heating self-balancing fixing device is disposed outside the optical housing opposite to the first entrance hole. The wafer self-balancing fixing device is disposed outside the optical housing opposite to the second entrance hole. An exit hole is provided on one of the two housing walls that are arranged opposite to each other along the second optical axis on the side of the semi-transparent and semi-reflective plane mirror away from the total reflection plane mirror. The light receiving end of the imaging device is disposed outside the optical housing opposite to the exit hole.

[0020] In one embodiment of this application, the semi-transparent and semi-reflective plane mirror is angle-adjustably disposed within the optical housing via a first angle adjustment device. The first angle adjustment device includes a plurality of first telescopic adjustment mechanisms arranged circumferentially at intervals along the semi-transparent and semi-reflective plane mirror. Each first telescopic adjustment mechanism includes a first mounting base, a first threaded sleeve, and a first threaded adjustment rod. The first threaded sleeve is rotatably disposed on the first mounting base about its own axis. The first threaded adjustment rod is threadedly engaged with the first threaded sleeve. The first mounting base and the first threaded adjustment rod are rotatably connected to the semi-transparent and semi-reflective plane mirror and the optical housing, respectively.

[0021] In one embodiment of this application, the total reflection plane mirror is angle-adjustably disposed within the optical housing via a second angle adjustment device. The second angle adjustment device includes a plurality of second telescopic adjustment mechanisms arranged circumferentially spaced along the total reflection plane mirror. Each second telescopic adjustment mechanism includes a second mounting base, a second threaded sleeve, and a second threaded adjustment rod. The second threaded sleeve is rotatably disposed on the second mounting base around its own axis. The second threaded adjustment rod is threadedly engaged with the second threaded sleeve. The second mounting base and the second threaded adjustment rod are rotatably connected to the total reflection plane mirror and the optical housing, respectively.

[0022] In one embodiment of this application, the substrate lighting device is disposed between the substrate heating self-balancing fixing device and the optical housing, and the substrate lighting device includes a first fixing ring and a plurality of first light-emitting elements evenly distributed on the first fixing ring in the circumferential direction.

[0023] In one embodiment of this application, the wafer illumination device is disposed between the wafer self-balancing fixing device and the optical housing, and the wafer illumination device includes a second fixing ring and a plurality of second light-emitting elements evenly distributed on the second fixing ring in the circumferential direction.

[0024] In one embodiment of this application, the imaging device is a long-focal-length variable-focus monocular microscope.

[0025] As can be seen from the above technical solutions, this invention discloses an optical imaging alignment system for precision flip-chip bonding. This optical imaging alignment system is used to align a substrate and a wafer. Alignment marks are respectively provided on the substrate and the wafer. The optical imaging alignment system includes a substrate heating self-balancing fixing device, a substrate illumination device, a wafer self-balancing fixing device, a wafer illumination device, a semi-transparent and semi-reflective plane mirror, a fully reflective plane mirror, and an imaging device. The substrate heating self-balancing fixing device, the semi-transparent and semi-reflective plane mirror, and the wafer self-balancing fixing device are arranged sequentially and at intervals along a first optical axis. The semi-transparent and semi-reflective plane mirror intersects the first optical axis at an angle. The substrate heating self-balancing fixing device has a function for fixing the substrate... The substrate fixing surface and the wafer self-balancing fixing device have a wafer fixing surface for fixing the wafer. Both the substrate fixing surface and the wafer fixing surface face the semi-transparent and semi-reflective plane mirror. The substrate heating self-balancing fixing device and the wafer self-balancing fixing device are used to make the substrate and the wafer parallel to each other. The substrate illumination device is used to image and illuminate the substrate on the substrate heating self-balancing fixing device, and the wafer illumination device is used to image and illuminate the wafer on the wafer self-balancing fixing device. The total reflection plane mirror, the semi-transparent and semi-reflective plane mirror and the imaging device are arranged sequentially and at intervals along the second optical axis. The first optical axis intersects the second optical axis. The reflecting surface of the total reflection plane mirror and the light receiving end of the imaging device face the semi-transparent and semi-reflective plane mirror.

[0026] In application, the substrate heating self-balancing fixing device fixes the substrate and adjusts its position, while the wafer self-balancing fixing device fixes the wafer and adjusts its position until the substrate and wafer are parallel and opposite. The substrate illumination device illuminates the substrate on the substrate heating self-balancing fixing device. The substrate light is reflected by a semi-transparent and semi-reflective plane mirror, reaches a fully reflective plane mirror, is reflected by the fully reflective plane mirror back to the semi-transparent and semi-reflective plane mirror, and then transmitted parallel through the semi-transparent and semi-reflective plane mirror into the imaging device. The wafer illumination device illuminates the wafer on the wafer self-balancing fixing device. The wafer light is reflected by a semi-transparent and semi-reflective plane mirror and enters the imaging device. When the alignment marks on the substrate and wafer images coincide, it indicates that the two are aligned. It can be seen that the above optical imaging alignment system achieves the alignment of the wafer and the substrate through imaging, which facilitates precise alignment. Moreover, it only uses a semi-transparent and semi-reflective plane mirror and a fully reflective plane mirror to form the optical structure, which is simple in structure, low in cost, and easy to implement. Attached Figure Description

[0027] 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, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of an optical imaging alignment system for precision flip-chip bonding provided in an embodiment of the present invention.

[0029] In the picture:

[0030] 1 is the substrate; 2 is the wafer; 3 is the first suction cup; 4 is the first spherical protrusion; 5 is a semi-transparent and semi-reflective plane mirror; 6 is the second suction cup; 7 is the second spherical protrusion; 8 is the fully reflective plane mirror; 9 is the imaging device; 10 is the substrate illumination device; 1001 is the first fixing ring; 1002 is the first light-emitting element; 11 is the wafer illumination device; 1101 is the second fixing ring; 1102 is the second light-emitting element; 12 is the optical housing; 13 is the first telescopic adjustment mechanism; 14 is the second telescopic adjustment mechanism. Detailed Implementation

[0031] The core of this invention is to provide an optical imaging alignment system for precision flip-chip bonding. The structural design of this optical imaging alignment system enables it to achieve alignment between the wafer and the substrate while being low-cost, with a simple optical system and easy to implement.

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of an optical imaging alignment system for precision flip-chip bonding provided in an embodiment of the present invention.

[0034] This invention discloses an optical imaging alignment system for precision flip-chip bonding. The optical imaging alignment system is used to align a substrate 1 and a wafer 2. The substrate 1 is a packaging substrate, including but not limited to a semiconductor substrate, a ceramic substrate, or a PCB substrate. Alignment marks and solder are arranged on the substrate 1. The solder is a gold-tin alloy, indium, tin-lead, or silver paste. The substrate 1 and the wafer 2 are bonded by thermosetting. The optical imaging alignment system includes a substrate heating self-balancing fixing device, a substrate illumination device 10, a wafer self-balancing fixing device, a wafer illumination device 11, a semi-transparent and semi-reflective plane mirror 5, a fully reflective plane mirror 8, and an imaging device 9.

[0035] The substrate heating self-balancing fixing device, the semi-transparent and semi-reflective plane mirror 5, and the wafer self-balancing fixing device are arranged sequentially and at intervals along the first optical axis. The semi-transparent and semi-reflective plane mirror 5 intersects the first optical axis at an angle. The substrate heating self-balancing fixing device has a substrate fixing surface for fixing the substrate 1, and the wafer self-balancing fixing device has a wafer fixing surface for fixing the wafer 2. Both the substrate fixing surface and the wafer fixing surface face the semi-transparent and semi-reflective plane mirror 5. The substrate heating self-balancing fixing device and the wafer self-balancing fixing device are used to make the substrate 1 and the wafer 2 parallel and opposite to each other. The substrate illumination device 10 is used for... Imaging illumination is provided for the substrate 1 on the self-balancing fixing device for substrate heating, and the wafer illumination device 11 is used to image and illuminate the wafer 2 on the self-balancing fixing device for wafer imaging. The total reflection plane mirror 8, the semi-transparent semi-reflective plane mirror 5, and the imaging device 9 are arranged sequentially at intervals along the second optical axis. The first optical axis intersects the second optical axis. In a specific embodiment of this case, the first optical axis is perpendicular to the second optical axis. The angle between the semi-transparent semi-reflective plane mirror 5 and both the first and second optical axes is 45°. The reflecting surface of the total reflection plane mirror 8 and the light receiving end of the imaging device 9 face the semi-transparent semi-reflective plane mirror 5.

[0036] In application, the substrate heating self-balancing fixing device fixes the substrate 1 and adjusts its position. The wafer self-balancing fixing device fixes the wafer 2 and adjusts its position until the substrate 1 and wafer 2 are parallel and opposite. The substrate illumination device 10 illuminates the substrate 1 on the substrate heating self-balancing fixing device. The light from the substrate 1 is reflected by the semi-transparent and semi-reflective plane mirror 5 and reaches the fully reflective plane mirror 8. After being reflected by the fully reflective plane mirror 8 back to the semi-transparent and semi-reflective plane mirror 5, it is transmitted parallel through the semi-transparent and semi-reflective plane mirror 5 and enters the imaging device 9 for imaging. The wafer illumination device 11 illuminates the wafer 2 on the wafer self-balancing fixing device. The light from the wafer 2 is reflected by the semi-transparent and semi-reflective plane mirror 5 and enters the imaging device 9 for imaging. When the alignment marks on the images of the substrate 1 and wafer 2 coincide, it indicates that the two are aligned.

[0037] Compared with the prior art, the optical imaging alignment system for precision flip-chip bonding provided in this embodiment of the invention achieves alignment between the wafer 2 and the substrate 1 through imaging, which facilitates precision alignment. Moreover, the optical structure is composed of only a semi-transparent and semi-reflective plane mirror 5 and a fully reflective plane mirror 8, which is simple in structure, low in cost, and easy to implement.

[0038] like Figure 1 As shown, the substrate heating self-balancing fixing device includes a first fixed base (not shown in the figure), a first suction cup 3, a heating device (not shown in the figure), and a first negative pressure device (not shown in the figure). The first fixed base is provided with a first spherical groove, and one side surface of the first suction cup 3 is provided with a first spherical protrusion 4. The first spherical groove and the first spherical protrusion 4 are engaged to allow the first fixed base and the first suction cup 3 to rotate relative to each other. The first suction cup 3 is made of a material that is resistant to high temperature, corrosion, chemically stable, and easy to process. In this case, the first suction cup 3 is made of stainless steel and is disc-shaped. The diameter of the first suction cup 3 is greater than or equal to the diameter of the substrate 1 to be adsorbed. One of the mating surfaces of the first spherical groove and the first spherical protrusion 4 is a concave spherical surface, and the other is a convex spherical surface, that is, the first suction cup 3 can swing freely relative to the first fixed base to achieve self-balancing adjustment.

[0039] The self-balancing base heating device uses negative pressure adsorption to fix the base 1. Therefore, multiple first air holes are provided on the surface of the first suction cup 3 away from the first spherical protrusion 4. To facilitate the positioning of the base 1, a limiting structure can also be provided on the surface of the first suction cup 3 away from the first spherical protrusion 4, i.e., the base fixing surface. The overall shape of the limiting structure matches the outer contour shape of the base 1. The limiting structure includes, but is not limited to, limiting grooves, multiple limiting protrusions that form the outer contour of the base 1, etc. The heating device is set inside the first suction cup 3, and the first negative pressure device is connected to each of the first air holes. The first negative pressure device includes, but is not limited to, a negative pressure fan. The heating device is used to heat the silver corner or preheat the base 1. The self-balancing base heating device with the above structure can meet the needs of 2-inch to 6-inch bases 1.

[0040] Specifically, the heating device includes a thermocouple, a resistance wire, and a temperature controller. The resistance wire is wound inside the first suction cup 3. The thermocouple is used to detect the temperature of the first suction cup 3. The temperature controller is used to control the working state of the circuit where the resistance wire is located based on the detection value of the thermocouple, so as to control the temperature of the first suction cup 3.

[0041] In one embodiment of this application, such as Figure 1 As shown, the wafer self-balancing fixing device adopts a similar structure to the above-mentioned substrate heating self-balancing fixing device. The wafer self-balancing fixing device includes a second fixing base (not shown in the figure), a second suction cup 6, and a second negative pressure device (not shown in the figure). The second fixing base is provided with a second spherical groove, and a second spherical protrusion 7 is provided on one side surface of the second suction cup 6. The second spherical groove and the second spherical protrusion 7 are engaged to allow the second fixing base and the second suction cup 6 to rotate relative to each other. The second suction cup 6 is made of a material that is resistant to high temperature, corrosion, chemically stable, and easy to process. The second suction cup 6 has a disc-shaped structure, and the diameter of the second suction cup 6 is greater than or equal to the diameter of the wafer 2 to be adsorbed. In this case, the second suction cup 6 is made of stainless steel. One of the mating surfaces of the second spherical groove and the second spherical protrusion 7 is a concave spherical surface, and the other is a convex spherical surface, that is, the second suction cup 6 can swing freely relative to the second fixing base to achieve self-balancing adjustment.

[0042] The self-balancing fixing device for wafers uses negative pressure adsorption to fix wafers 2. Therefore, multiple second air holes are provided on the side surface of the second suction cup 6 away from the second spherical protrusion 7. The second negative pressure device is connected to each of the second air holes. In order to facilitate the positioning of wafers 2, a limiting structure can also be provided on the side surface of the second suction cup 6 away from the second spherical protrusion 7, that is, the wafer fixing surface. The overall shape of the limiting structure matches the outer contour shape of the wafer 2. The limiting structure includes, but is not limited to, limiting grooves, multiple limiting protrusions that form the outer contour of the wafer 2, etc. The self-balancing fixing device for wafers with the above structure can meet the needs of wafers 2 within 10x10mm.

[0043] To improve image quality and reduce external interference, such as Figure 1 As shown, in one embodiment of this application, the optical imaging alignment system further includes an optical housing 12. The optical housing 12 is made of a material that is not easily corroded and has a certain strength, such as aluminum alloy. A semi-transparent and semi-reflective plane mirror 5 and a fully reflective plane mirror 8 are disposed inside the optical housing 12. A first entrance hole and a second entrance hole are respectively disposed on two housing walls that are arranged opposite to each other along the first optical axis. A substrate heating self-balancing fixing device is disposed opposite to the first entrance hole outside the optical housing 12. A wafer self-balancing fixing device is disposed opposite to the second entrance hole outside the optical housing 12. An exit hole is disposed on the side of the semi-transparent and semi-reflective plane mirror 5 away from the fully reflective plane mirror 8 in one of the two housing walls that are arranged opposite to each other along the second optical axis. The light receiving end of the imaging device 9 is disposed opposite to the exit hole outside the optical housing 12.

[0044] In one specific embodiment of this application, the optical housing 12 is a cuboid structure with a wall thickness of 3mm and dimensions of 50mm×50mm×60mm.

[0045] In one specific embodiment, the semi-transparent and semi-reflective plane mirror 5 is a circular disc structure with a diameter of 2 cm and a thickness of 0.5 mm. It is made of quartz and coated with a semi-transparent and semi-reflective film. It is positioned 102-4 cm away from the substrate illumination device. This semi-transparent and semi-reflective plane mirror 5 is used for imaging both the substrate 1 and the wafer 2. The total reflection plane mirror 8 is located 2-3 cm below the semi-transparent and semi-reflective plane mirror 5. It is also a circular disc structure with a diameter of 2 cm and a thickness of 0.5 mm. It is made of quartz and coated with a total reflection silver film to prevent astigmatism distortion.

[0046] Further optimize the above technical solutions, such as Figure 1 As shown, the semi-transparent and semi-reflective plane mirror 5 is angle-adjustably mounted inside the optical housing 12 via a first angle adjustment device. The first angle adjustment device includes multiple first telescopic adjustment mechanisms 13 arranged circumferentially along the semi-transparent and semi-reflective plane mirror 5. The first telescopic adjustment mechanisms 13 are preferably made of a material that is not easily corroded. In this case, the first telescopic adjustment mechanisms 13 are made of stainless steel. The first telescopic adjustment mechanism 13 includes a first mounting base, a first threaded sleeve, and a first threaded adjustment rod. The first threaded sleeve is rotatably mounted on the first mounting base around its own axis. The first threaded adjustment rod is threadedly engaged with the first threaded sleeve. The first mounting base and the first threaded adjustment rod are rotatably connected to the semi-transparent and semi-reflective plane mirror 5 and the optical housing 12, respectively. Through the aforementioned first angle adjustment device, the micro-adjustment of the semi-transparent and semi-reflective plane mirror 5 can be realized, which is used to precisely control the position and angle of the semi-transparent and semi-reflective plane mirror 5.

[0047] Accordingly, such as Figure 1As shown, the total reflection plane mirror 8 is angle-adjustably mounted inside the optical housing 12 via a second angle adjustment device. The second angle adjustment device includes multiple second telescopic adjustment mechanisms 14 arranged circumferentially around the total reflection plane mirror 8. The second telescopic adjustment mechanisms 14 are preferably made of a material that is not easily corroded. In this case, the second telescopic adjustment mechanisms 14 are made of stainless steel. The second telescopic adjustment mechanism 14 includes a second mounting base, a second threaded sleeve, and a second threaded adjustment rod. The second threaded sleeve is rotatably mounted on the second mounting base around its own axis. The second threaded adjustment rod is threadedly engaged with the second threaded sleeve. The second mounting base and the second threaded adjustment rod are rotatably connected to the total reflection plane mirror 8 and the optical housing 12, respectively. Through the above-mentioned second angle adjustment device, the total reflection plane mirror 8 can be finely adjusted for precise control of its position and angle.

[0048] like Figure 1 As shown, the substrate lighting device 10 is disposed between the substrate heating self-balancing fixing device and the optical housing 12. The substrate lighting device 10 includes a first fixing ring 1001 and a plurality of first light-emitting elements 1002 evenly distributed on the first fixing ring 1001 in the circumferential direction. In a specific embodiment, the first light-emitting element 1002 is an LED white light bulb. Eight LED white light bulbs are arranged in the circumferential direction of the first fixing ring 1001, and the distance between the first fixing ring 1001 and the substrate 1 is 1cm-2cm.

[0049] The chip illumination device 11 and the substrate illumination device 10 have basically the same structure, such as Figure 1 As shown, the chip illumination device 11 is disposed between the chip self-balancing fixing device and the optical housing 12. The chip illumination device 11 includes a second fixing ring 1101 and a plurality of second light-emitting elements 1102 evenly distributed on the second fixing ring 1101 in the circumferential direction. In a specific embodiment, the second light-emitting element 1102 is an LED white light bulb. Eight LED white light bulbs are arranged in the circumferential direction of the second fixing ring 1101, and the distance between the ring and the chip 2 is 1cm-2cm.

[0050] In one specific embodiment of this application, the imaging device 9 is a long-focal-length variable-focus monocular microscope. The long-focal-length variable-focus monocular microscope is located on the side of the semi-transparent and semi-reflective plane mirror 5 away from the total reflection plane mirror 8. The object distance is greater than 80mm, the zoom magnification is 0.5-12 times, and it has a high-resolution (1024×1080) high-contrast CCD with an overall magnification greater than 600 times.

[0051] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0052] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. An optical imaging alignment system for flip chip precision bonding, for aligning a substrate and a wafer, the substrate and the wafer respectively provided with alignment marks thereon, characterized in that, The self-balancing fixing device comprises a substrate heating self-balancing fixing device, a substrate illuminating device, a wafer self-balancing fixing device, a wafer illuminating device, a half-transmissive half-reflective plane mirror, a full-reflective plane mirror and an imaging device. The substrate heating self-balancing fixing device, the half-transmissive half-reflective plane mirror and the wafer self-balancing fixing device are sequentially and spacedly arranged along a first optical axis, the half-transmissive half-reflective plane mirror is obliquely intersected with the first optical axis, the substrate heating self-balancing fixing device has a substrate fixing surface for fixing the substrate, the wafer self-balancing fixing device has a wafer fixing surface for fixing the wafer, the substrate fixing surface and the wafer fixing surface are both directed to the half-transmissive half-reflective plane mirror, the substrate heating self-balancing fixing device and the wafer self-balancing fixing device are used for making the substrate and the wafer parallel to each other, the substrate illuminating device is used for imaging and illuminating the substrate on the substrate heating self-balancing fixing device, and the wafer illuminating device is used for imaging and illuminating the wafer on the wafer self-balancing fixing device. The full-reflective plane mirror, the half-transmissive half-reflective plane mirror and the imaging device are sequentially and spacedly arranged along a second optical axis, the first optical axis and the second optical axis are intersected, and a reflecting surface of the full-reflective plane mirror and a light receiving end of the imaging device are both directed to the half-transmissive half-reflective plane mirror.

2. The optical imaging alignment system for flip chip precision flip-chip bonding according to claim 1, wherein, The substrate heating self-balancing fixing device comprises: a first fixing base provided with a first spherical clamping groove; a first suction disc provided with a first spherical convex on one side surface, the first spherical clamping groove and the first spherical convex are clamped and matched to make the first fixing base and the first suction disc relatively rotatable, one of matching surfaces of the first spherical clamping groove and the first spherical convex is a concave spherical surface, and the other is a convex spherical surface, and a plurality of first air holes are arranged on the side surface of the first suction disc away from the first spherical convex; a heating device arranged in the first suction disc; a first negative pressure device connected with each first air hole.

3. The optical imaging alignment system for flip chip precision flip-chip bonding according to claim 2, wherein, The heating device comprises a thermocouple, a resistance wire and a temperature controller, the resistance wire is coiled in the first suction disc, the thermocouple is used for detecting the temperature of the first suction disc, and the temperature controller is used for controlling the working state of a circuit in which the resistance wire is located according to the detection value of the thermocouple.

4. The optical imaging alignment system for flip chip precision flip-chip bonding according to claim 1, wherein, The wafer self-balancing fixing device comprises: a second fixing base provided with a second spherical clamping groove; a second suction disc provided with a second spherical convex on one side surface, the second spherical clamping groove and the second spherical convex are clamped and matched to make the second fixing base and the second suction disc relatively rotatable, one of matching surfaces of the second spherical clamping groove and the second spherical convex is a concave spherical surface, and the other is a convex spherical surface, and a plurality of second air holes are arranged on the side surface of the second suction disc away from the second spherical convex; a second negative pressure device connected with each second air hole.

5. The optical imaging alignment system for flip chip precision flip-chip bonding according to claim 1, wherein, The optical box is provided with a first entrance hole and a second entrance hole on two opposite walls along the first optical axis, the substrate self-balancing fixing device is arranged outside the optical box opposite to the first entrance hole, the wafer self-balancing fixing device is arranged outside the optical box opposite to the second entrance hole, and one of the two opposite walls along the second optical axis is provided with an exit hole on the side away from the total reflection plane mirror.

6. The optical imaging alignment system for flip chip precision flip-chip bonding according to claim 5, wherein, The semi-transmissive and semi-reflective plane mirror is adjustably arranged in the optical box through a first angle adjusting device, the first angle adjusting device comprises a plurality of first telescopic adjusting mechanisms arranged at intervals along the circumference of the semi-transmissive and semi-reflective plane mirror, the first telescopic adjusting mechanism comprises a first mounting seat, a first threaded sleeve and a first threaded adjusting rod, the first threaded sleeve is rotatably arranged on the first mounting seat, and the first threaded adjusting rod is threadedly connected with the first threaded sleeve.

7. The optical imaging alignment system for flip chip precision flip-chip bonding according to claim 5, wherein, The total reflection plane mirror is adjustably arranged in the optical box through a second angle adjusting device, the second angle adjusting device comprises a plurality of second telescopic adjusting mechanisms arranged at intervals along the circumference of the total reflection plane mirror, the second telescopic adjusting mechanism comprises a second mounting seat, a second threaded sleeve and a second threaded adjusting rod, the second threaded sleeve is rotatably arranged on the second mounting seat, and the second threaded adjusting rod is threadedly connected with the second threaded sleeve.

8. The optical imaging alignment system for flip chip precision flip-chip bonding according to claim 5, wherein, The substrate illuminating device is arranged between the substrate self-balancing fixing device and the optical box, and the substrate illuminating device comprises a first fixing ring and a plurality of first light emitting elements uniformly distributed on the first fixing ring in the circumferential direction.

9. The optical imaging alignment system for flip chip precision flip-chip bonding according to claim 5, wherein, The wafer illuminating device is arranged between the wafer self-balancing fixing device and the optical box, and the wafer illuminating device comprises a second fixing ring and a plurality of second light emitting elements uniformly distributed on the second fixing ring in the circumferential direction.

10. The optical imaging alignment system for flip chip precision flip-chip bonding according to any one of claims 1-9, wherein, The imaging device is a long-focus variable-focus monocular microscope.

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