Optical imaging alignment system for chip precision flip-chip bonding

Abstract

The invention relates to an optical imaging alignment system for chip precision flip-chip bonding, which comprises a substrate heating self-balancing fixing device, a substrate lighting device, a wafer self-balancing fixing device, a wafer lighting device, a semi-transparent and semi-reflecting plane mirror, a total-reflecting plane mirror and an imaging device, the substrate heating self-balancing fixing device, the semi-transmitting and semi-reflecting plane mirror and the wafer self-balancing fixing device are sequentially arranged at intervals along the first optical axis, the semi-transmitting and semi-reflecting plane mirror and the first optical axis are obliquely intersected, and the substrate fixing surface and the wafer fixing surface both face the semi-transmitting and semi-reflecting plane mirror; the total-reflection plane mirror, the semi-transparent and semi-reflection plane mirror and the imaging device are sequentially arranged at intervals along the second optical axis, the first optical axis intersects with the second optical axis, and the reflection face of the total-reflection plane mirror and the light receiving end of the imaging device face the semi-transparent and semi-reflection plane mirror. According to the optical imaging alignment system, alignment of the wafer and the substrate is achieved in an imaging mode, precise alignment is conveniently achieved, and the optical imaging alignment system is simple in optical structure, low in cost and easy to achieve.

Description

Technical Field

[0001] The invention relates to the technical field of photon optoelectronic device design, and in particular to an optical imaging alignment system for precise chip flip-chip bonding. Background Art

[0002] In recent years, with the in-depth development of silicon-based photonics, people have successfully realized the integration of passive devices such as optical switches and optical waveguides on the SOI platform. However, the research on the core device Si laser has been slow, mainly because Si is an indirect bandgap semiconductor with low luminous efficiency. At present, the more mature method is to integrate III-V materials with Si heterogeneously through bonding methods to realize the output of III-V light sources from Si waveguides. The hybrid integration of III-V (such as GaAs, InP, etc.) materials and silicon is currently considered to be the most promising photonic or optoelectronic chip technology suitable for high-density integration. Usually, SOI materials (Si / SiO2 / Si substrates) with waveguide structures are bonded with III-V epitaxial materials through organic materials or bonding methods, and the III-V substrate is removed. Then, photonic or optoelectronic devices and optical paths are processed. The light waves are coupled into the lower SOI waveguide through the evanescent field, and the electrical injection is completed in the III-V material layer using coplanar electrodes. Among them, the bonding technology is very important. There are several problems with the surface light source formed by wafer bonding. First, most CMOS factories do not allow the processing of III-V materials for fear of introducing contamination. Second, the yield rate is relatively low if the materials are bonded together before making the laser. Third, the diameter of III-V wafers is relatively small while the diameter of silicon-based materials is relatively large, so bonding the wafers and then performing the process results in serious waste.

[0003] A more feasible method is to first make the III-V laser die or array through conventional semiconductor processes, screen them, and then integrate them through various coupling methods. However, it is very difficult to obtain high coupling efficiency. The difficulty lies in the coupling of active and passive waveguide devices. The usual coupling waveguides are wedge-shaped and anti-wedge-shaped waveguide structures, which require the lateral alignment accuracy between the laser unit and the waveguide center to be in the sub-micron or even deep sub-micron accuracy. The commonly used method is flip-chip welding. The flip-chip welding equipment uses a suction head to hold the wafer, and then finds the target position through complex imaging and alignment to achieve bonding. It is usually required that the end face of the suction head is absolutely parallel to the plane of the target wafer, otherwise there will be problems such as loose bonding and low coupling efficiency. Summary of the invention

[0004] The purpose of the present invention is to provide an optical imaging alignment system for chip precision flip-chip bonding, so that it can achieve alignment between the chip and the substrate while having the characteristics of low cost, simple optical system and easy implementation.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] An optical imaging alignment system for chip precision flip-chip bonding, used for aligning a substrate and a wafer, the substrate and the wafer are respectively provided with alignment marks, comprising a substrate heating self-balancing fixture, a substrate lighting device, a wafer self-balancing fixture, a wafer lighting device, a semi-transparent and semi-reflective plane mirror, a fully reflective plane mirror and an imaging device;

[0007] The substrate heating self-balancing fixture, the semi-transparent and semi-reflective plane mirror and the wafer self-balancing fixture are sequentially arranged at intervals along the first optical axis, the semi-transparent and semi-reflective plane mirror is tilted and intersected with the first optical axis, the substrate heating self-balancing fixture has a substrate fixing surface for fixing the substrate, the wafer self-balancing fixture has a wafer fixing surface for fixing the wafer, the substrate fixing surface and the wafer fixing surface are both facing the semi-transparent and semi-reflective plane mirror, the substrate heating self-balancing fixture and the wafer self-balancing fixture are used to make the substrate parallel to the wafer, the substrate lighting device is used to perform imaging lighting on the substrate on the substrate heating self-balancing fixture, and the wafer lighting device is used to perform imaging lighting on the wafer on the wafer self-balancing fixture;

[0008] The total reflection plane mirror, the semi-transparent and semi-reflective plane mirror and the imaging device are arranged in sequence 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 the present application, the substrate heating self-balancing fixing device comprises:

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

[0011] A first suction cup, wherein a first spherical protrusion is disposed on one side surface of the first suction cup, the first spherical groove is engaged 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 groove and the first spherical protrusion is a concave spherical surface, and the other is a convex spherical surface, and a plurality of first air holes are disposed on a side surface of the first suction cup away from the first spherical protrusion;

[0012] A heating device, the heating device is arranged in the first suction cup;

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

[0014] In one embodiment of the present application, the heating device includes a thermocouple, a resistance wire and a temperature controller, the resistance wire is coiled in the first suction cup, the thermocouple is used to detect the temperature of the first suction cup, and the temperature controller is used to control the working state of the circuit where the resistance wire is located according to the detection value of the thermocouple.

[0015] In one embodiment of the present application, the wafer self-balancing fixture comprises:

[0016] A second fixed base, wherein the second fixed base is provided with a second spherical groove;

[0017] A second suction cup, wherein a second spherical protrusion is disposed on one side surface of the second suction cup, and the second spherical clamping groove is engaged with the second spherical protrusion so that the second fixed base and the second suction cup can rotate relative to each other, and one of the mating surfaces of the second spherical clamping groove and the second spherical protrusion is a concave spherical surface, and the other is a convex spherical surface, and a plurality of second air holes are disposed on a side surface of the second suction cup away from the second spherical protrusion;

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

[0019] In one embodiment of the present application, it also includes an optical box, the semi-transparent and semi-reflective plane mirror and the total-reflective plane mirror are arranged in the optical box, and a first entrance hole and a second entrance hole are respectively arranged on two box walls of the optical box that are arranged opposite to each other along the first optical axis, the substrate heating self-balancing fixture is arranged outside the optical box opposite to the first entrance hole, the wafer self-balancing fixture is arranged outside the optical box opposite to the second entrance hole, an exit hole is arranged on one of the two box walls of the optical box that are arranged opposite to each other along the second optical axis and is located on a side of the semi-transparent and semi-reflective plane mirror away from the total-reflective plane mirror, and the light receiving end of the imaging device is arranged outside the optical box opposite to the exit hole.

[0020] In one embodiment of the present application, the semi-transparent and semi-reflective plane mirror is adjustably arranged in the optical box through a first angle adjustment device, the first angle adjustment device includes a plurality of first telescopic adjustment mechanisms arranged at intervals along the circumference of the semi-transparent and semi-reflective plane mirror, the first telescopic adjustment mechanism includes a first mounting seat, a first threaded sleeve and a first threaded adjustment rod, the first threaded sleeve can be rotatably arranged on the first mounting seat around its own axis, the first threaded adjustment rod is threadedly matched with the first threaded sleeve, the first mounting seat and the first threaded adjustment rod are rotatably connected to the semi-transparent and semi-reflective plane mirror and the optical box respectively.

[0021] In one embodiment of the present application, the total-reflective plane mirror is adjustably arranged in the optical box through a second angle adjustment device, the second angle adjustment device includes a plurality of second telescopic adjustment mechanisms arranged at intervals along the circumference of the total-reflective plane mirror, the second telescopic adjustment mechanism includes a second mounting seat, a second threaded sleeve and a second threaded adjustment rod, the second threaded sleeve can be rotatably arranged on the second mounting seat around its own axis, the second threaded adjustment rod is threadedly matched with the second threaded sleeve, and the second mounting seat and the second threaded adjustment rod are rotatably connected to the total-reflective plane mirror and the optical box respectively.

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

[0023] In one embodiment of the present application, the chip lighting device is disposed between the chip self-balancing fixture and the optical box, and the chip lighting device includes a second fixing ring and a plurality of second light-emitting elements uniformly distributed on the second fixing ring along the circumferential direction.

[0024] In one embodiment of the present application, the imaging device is a telephoto and variable-focus monocular microscope.

[0025] It can be seen from the above technical scheme that the present invention discloses an optical imaging alignment system for chip precision flip-chip bonding, the optical imaging alignment system is used to align a substrate with a wafer, and alignment marks are respectively arranged on the substrate and the wafer, and the optical imaging alignment system comprises a substrate heating self-balancing fixture, a substrate lighting device, a wafer self-balancing fixture, a wafer lighting device, a semi-transparent and semi-reflective plane mirror, a fully reflective plane mirror and an imaging device, wherein the substrate heating self-balancing fixture, the semi-transparent and semi-reflective plane mirror and the wafer self-balancing fixture are sequentially arranged at intervals along a first optical axis, the semi-transparent and semi-reflective plane mirror is inclined to intersect with the first optical axis, and the substrate heating self-balancing fixture has a structure for fixing the substrate. The wafer self-balancing fixture has a wafer fixing surface for fixing the wafer, the substrate fixing surface and the wafer fixing surface are both facing the semi-transparent and semi-reflective plane mirror, the substrate heating self-balancing fixture and the wafer self-balancing fixture are used to make the substrate and the wafer parallel and opposite, the substrate lighting device is used to perform imaging lighting on the substrate on the substrate heating self-balancing fixture, and the wafer lighting device is used to perform imaging lighting on the wafer on the wafer self-balancing fixture; the fully-reflective plane mirror, the semi-transparent and semi-reflective plane mirror and the imaging device are arranged in sequence along the second optical axis, the first optical axis intersects the second optical axis, and the reflecting surface of the fully-reflective plane mirror and the light receiving end of the imaging device face the semi-transparent and semi-reflective plane mirror.

[0026] When in use, the substrate heating self-balancing fixture fixes the substrate and adjusts the position of the substrate, the wafer self-balancing fixture fixes the wafer and adjusts the position of the wafer until the substrate is parallel to the wafer, the substrate lighting device performs imaging lighting on the substrate on the substrate heating self-balancing fixture, the substrate light is reflected by the semi-transparent and semi-reflective plane mirror, reaches the total-reflective plane mirror, and is reflected by the total-reflective plane mirror to the semi-transparent and semi-reflective plane mirror, and then is transmitted parallel to the semi-transparent and semi-reflective plane mirror into the imaging device for imaging, the wafer lighting device performs imaging lighting on the wafer on the wafer self-balancing fixture, the wafer light is reflected by the semi-transparent and semi-reflective plane mirror and enters the imaging device for imaging, when the alignment marks on the substrate and the wafer imaging coincide, it indicates that the two are aligned, it can be seen that the above-mentioned optical imaging alignment system realizes the alignment of the wafer and the substrate by imaging, which is convenient for precise alignment, and only uses a semi-transparent and semi-reflective plane mirror and a total-reflective plane mirror to form an optical structure, which has a simple structure, low cost, and is easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

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

[0029] In the figure:

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

[0031] The core of the present invention is to provide an optical imaging alignment system for chip precision flip-chip bonding. The structural design of the optical imaging alignment system enables it to achieve alignment between the chip and the substrate while having the characteristics of low cost, simple optical system and easy implementation.

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] See also Figure 1 , Figure 1 A schematic diagram of the structure of an optical imaging alignment system for chip precision flip-chip bonding provided by an embodiment of the present invention.

[0034] An embodiment of the present invention discloses an optical imaging alignment system for chip precision flip-chip bonding, the optical imaging alignment system is used to align a substrate 1 with a wafer 2, the substrate 1 is a packaging substrate 1, including but not limited to a semiconductor substrate, a ceramic substrate, and a PCB board substrate, the substrate 1 is provided with alignment marks and solder, the solder is a gold-tin alloy, indium, tin-lead, etc., and can also be silver glue, the substrate 1 and the wafer 2 are bonded by thermal curing bonding, the optical imaging alignment system comprises a substrate heating self-balancing fixing device, a substrate lighting device 10, a wafer self-balancing fixing device, a wafer lighting device 11, a semi-transparent and semi-reflective plane mirror 5, a fully-reflective plane mirror 8 and an imaging device 9.

[0035] Among them, the substrate heating self-balancing fixture, the semi-transparent and semi-reflective plane mirror 5 and the wafer self-balancing fixture are arranged in sequence along the first optical axis, the semi-transparent and semi-reflective plane mirror 5 is tilted and intersected with the first optical axis, the substrate heating self-balancing fixture has a substrate fixing surface for fixing the substrate 1, the wafer self-balancing fixture has a wafer fixing surface for fixing the wafer 2, the substrate fixing surface and the wafer fixing surface are both facing the semi-transparent and semi-reflective plane mirror 5, the substrate heating self-balancing fixture and the wafer self-balancing fixture are used to make the substrate 1 parallel to the wafer 2, and the substrate lighting device 10 is used The substrate 1 on the substrate heating self-balancing fixture is imaged and illuminated, and the chip illumination device 11 is used to image and illuminate the chip 2 on the chip self-balancing fixture; the total reflection plane mirror 8, the semi-transparent and semi-reflective plane mirror 5 and the imaging device 9 are arranged in sequence along the second optical axis, and the first optical axis intersects the second optical axis. In a specific embodiment of the present case, the first optical axis is perpendicular to the second optical axis, and the angles between the semi-transparent and semi-reflective plane mirror 5 and the first and second optical axes are both 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 and semi-reflective plane mirror 5.

[0036] When in use, the substrate heating self-balancing fixture fixes the substrate 1 and adjusts the position of the substrate 1, the wafer self-balancing fixture fixes the wafer 2 and adjusts the position of the wafer 2 until the substrate 1 is parallel to the wafer 2, the substrate lighting device 10 performs imaging lighting on the substrate 1 on the substrate heating self-balancing fixture, the light of the substrate 1 is reflected by the semi-transparent and semi-reflective plane mirror 5, reaches the total-reflective plane mirror 8, and is reflected by the total-reflective plane mirror 8 to the semi-transparent and semi-reflective plane mirror 5, and is transmitted parallel to the semi-transparent and semi-reflective plane mirror 5 to enter the imaging device 9 for imaging, the wafer lighting device 11 performs imaging lighting on the wafer 2 on the wafer self-balancing fixture, the light of the wafer 2 is reflected by the semi-transparent and semi-reflective plane mirror 5 to enter the imaging device 9 for imaging, and when the alignment marks on the imaging of the substrate 1 and the wafer 2 coincide, it indicates that the two are aligned.

[0037] Compared with the prior art, the optical imaging alignment system for chip precision flip-chip bonding provided in the embodiment of the present invention realizes the alignment of the chip 2 and the substrate 1 by imaging, which facilitates the realization of precise alignment, and only uses a semi-transparent and semi-reflective plane mirror 5 and a fully-reflective plane mirror 8 to form an optical structure, which has a simple structure, low cost and is 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), wherein the first fixed base is provided with a first spherical groove, and a first spherical protrusion 4 is provided on one side surface of the first suction cup 3. The first spherical groove and the first spherical protrusion 4 are engaged with each other so that the first fixed base and the first suction cup 3 can rotate relative to each other. The first suction cup 3 is made of a material that is resistant to high temperature, corrosion-resistant, chemically stable and easy to process. In this case, the first suction cup 3 is made of stainless steel, and the first suction cup 3 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 substrate heating self-balancing fixing device fixes the substrate 1 by negative pressure adsorption. Therefore, a plurality of first air holes are arranged on the surface of the side of the first suction cup 3 away from the first spherical protrusion 4. To facilitate the positioning of the substrate 1, a limiting structure can also be arranged on the surface of the side of the first suction cup 3 away from the first spherical protrusion 4, that is, on the substrate fixing surface. The overall shape of the limiting structure is consistent with the outer contour of the substrate 1. The limiting structure includes but is not limited to a limiting groove, a plurality of limiting bosses surrounding the outer contour of the substrate 1, and the like. The heating device is arranged in the first suction cup 3, and the first negative pressure device is connected to each first air hole. 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 substrate 1. The substrate heating self-balancing fixing device using the above structure can meet the needs of 2-inch to 6-inch substrates 1.

[0040] Specifically, the above-mentioned heating device includes a thermocouple, a resistance wire and a temperature controller. The resistance wire is coiled in 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 according to the detection value of the thermocouple to achieve control of the temperature of the first suction cup 3.

[0041] In one embodiment of the present application, Figure 1 As shown, the wafer self-balancing fixture adopts a similar structure to the above-mentioned substrate heating self-balancing fixture, and the wafer self-balancing fixture includes a second fixed base (not shown in the figure), a second suction cup 6 and a second negative pressure device (not shown in the figure), wherein the second fixed 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 with each other so that the second fixed base and the second suction cup 6 can 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 is 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, and 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 fixed base to achieve self-balancing adjustment.

[0042] The chip self-balancing fixing device fixes the chip 2 by negative pressure adsorption. Therefore, a plurality of second air holes are arranged 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 second air hole. To facilitate the positioning of the chip 2, a limiting structure can also be arranged on the side surface of the second suction cup 6 away from the second spherical protrusion 7, that is, the chip fixing surface. The overall shape of the limiting structure is consistent with the outer contour of the chip 2. The limiting structure includes but is not limited to a limiting groove, a plurality of limiting bosses surrounding the outer contour of the chip 2, and the like. The chip self-balancing fixing device adopting the above structure can meet the needs of chips 2 within 10x10mm.

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

[0044] In a specific embodiment of the present application, the optical box 12 is a rectangular parallelepiped structure with a wall thickness of 3 mm and a size of 50 mm×50 mm×60 mm.

[0045] In a specific embodiment, the semi-transparent and semi-reflective plane mirror 5 is a disc structure with a diameter of 2 cm, a thickness of 0.5 mm, and a material of quartz, on which a semi-transparent and semi-reflective film is coated. The distance from the substrate lighting device is 102-4 cm. The semi-transparent and semi-reflective plane mirror 5 is used for imaging the substrate 1 and the wafer 2 at the same time. The fully reflective plane mirror 8 is located 2 cm-3 cm below the semi-transparent and semi-reflective plane mirror 5, and is a disc structure with a diameter of 2 cm, a thickness of 0.5 mm, and a material of quartz, on which a fully reflective silver film is coated to prevent imaging astigmatism distortion.

[0046] Further optimize the above technical solution, such as Figure 1 As shown, the semi-transparent and semi-reflective plane mirror 5 is adjustably arranged in the optical box 12 through a first angle adjustment device, and the first angle adjustment device includes a plurality of first telescopic adjustment mechanisms 13 arranged at intervals along the circumference of the semi-transparent and semi-reflective plane mirror 5. The first telescopic adjustment mechanism 13 is preferably made of a material that is not easy to rust. In the present case, the first telescopic adjustment mechanism 13 is made of stainless steel. The first telescopic adjustment mechanism 13 includes a first mounting seat, a first threaded sleeve and a first threaded adjustment rod. The first threaded sleeve can be rotatably arranged on the first mounting seat around its own axis, and the first threaded adjustment rod is threadedly matched with the first threaded sleeve. The first mounting seat and the first threaded adjustment rod are rotatably connected to the semi-transparent and semi-reflective plane mirror 5 and the optical box 12 respectively. The first angle adjustment device can realize micro-adjustment of the semi-transparent and semi-reflective plane mirror 5, which is used to precisely control the position and angle of the semi-transparent and semi-reflective plane mirror 5.

[0047] Accordingly, if Figure 1As shown, the total reflection plane mirror 8 is adjustably arranged in the optical box 12 by a second angle adjustment device, and the second angle adjustment device includes a plurality of second telescopic adjustment mechanisms 14 arranged at intervals along the circumference of the total reflection plane mirror 8. The second telescopic adjustment mechanism 14 is preferably made of a material that is not easy to rust. In the present case, the second telescopic adjustment mechanism 14 is made of stainless steel. The second telescopic adjustment mechanism 14 includes a second mounting seat, a second threaded sleeve and a second threaded adjustment rod. The second threaded sleeve can be rotatably arranged on the second mounting seat around its own axis, and the second threaded adjustment rod is threadedly matched with the second threaded sleeve. The second mounting seat and the second threaded adjustment rod are rotatably connected to the total reflection plane mirror 8 and the optical box 12 respectively. The above-mentioned second angle adjustment device can realize micro-adjustment of the total reflection plane mirror 8, which is used to precisely control the position and angle of the total reflection plane mirror 8.

[0048] like Figure 1 As shown, the base lighting device 10 is arranged between the base heating self-balancing fixing device and the optical box 12. The base lighting device 10 includes a first fixing ring 1001 and a plurality of first light-emitting elements 1002 uniformly distributed on the first fixing ring 1001 along the circumferential direction. In a specific embodiment, in this case, the first light-emitting element 1002 is an LED white light lamp bead. Eight LED white light lamp beads are arranged on the circumference of the first fixing ring 1001, and the distance between the first fixing ring 1001 and the base 1 is 1cm-2cm.

[0049] The wafer illumination device 11 has a substantially similar structure to the substrate illumination device 10. Figure 1 As shown, the chip lighting device 11 is arranged between the chip self-balancing fixture and the optical box 12. The chip lighting device 11 includes a second fixing ring 1101 and a plurality of second light-emitting elements 1102 uniformly distributed circumferentially on the second fixing ring 1101. In a specific embodiment, in this case, the second light-emitting element 1102 is an LED white light bead. Eight LED white light beads are arranged circumferentially on the second fixing ring 1101, and the distance between them and the chip 2 is 1cm-2cm.

[0050] In a specific embodiment of the present application, the imaging device 9 is a telephoto variable-focus monocular microscope, which is located on the side of the semi-transparent and semi-reflective plane mirror 5 away from the total-reflective plane mirror 8, with an object distance greater than 80 mm, a zoom factor of 0.5-12 times, and a high-resolution (1024×1080) high-contrast CCD, and 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, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0052] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. An optical imaging alignment system for precision flip-chip bonding, used for aligning a substrate with a wafer, wherein alignment marks are provided on the substrate and the wafer, respectively, and characterized in that: It includes a substrate heating self-balancing fixture, a substrate lighting device, a wafer self-balancing fixture, a wafer lighting device, a semi-transparent and semi-reflective plane mirror, a fully-reflective plane mirror and an imaging device; The substrate heating self-balancing fixture, the semi-transparent and semi-reflective plane mirror and the wafer self-balancing fixture are sequentially arranged at intervals along the first optical axis, the semi-transparent and semi-reflective plane mirror is tilted and intersected with the first optical axis, the substrate heating self-balancing fixture has a substrate fixing surface for fixing the substrate, the wafer self-balancing fixture has a wafer fixing surface for fixing the wafer, the substrate fixing surface and the wafer fixing surface are both facing the semi-transparent and semi-reflective plane mirror, the substrate heating self-balancing fixture and the wafer self-balancing fixture are used to make the substrate parallel to the wafer, the substrate lighting device is used to perform imaging lighting on the substrate on the substrate heating self-balancing fixture, and the wafer lighting device is used to perform imaging lighting on the wafer on the wafer self-balancing fixture; The total reflection plane mirror, the semi-transparent and semi-reflective plane mirror and the imaging device are arranged in sequence 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.

2. The optical imaging alignment system for chip precision flip-chip bonding according to claim 1, characterized in that: The substrate heating self-balancing fixing device comprises: A first fixed base, wherein the first fixed base is provided with a first spherical groove; A first suction cup, wherein a first spherical protrusion is disposed on one side surface of the first suction cup, the first spherical groove is engaged 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 groove and the first spherical protrusion is a concave spherical surface, and the other is a convex spherical surface, and a plurality of first air holes are disposed on a side surface of the first suction cup away from the first spherical protrusion; A heating device, the heating device is arranged in the first suction cup; A first negative pressure device is connected to each of the first air holes.

3. The optical imaging alignment system for chip precision flip-chip bonding according to claim 2, characterized in that: The heating device includes a thermocouple, a resistance wire and a temperature controller. The resistance wire is coiled in 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 working state of the circuit where the resistance wire is located according to the detection value of the thermocouple.

4. The optical imaging alignment system for chip precision flip-chip bonding according to claim 1, characterized in that: The wafer self-balancing fixture comprises: A second fixed base, wherein the second fixed base is provided with a second spherical groove; A second suction cup, wherein a second spherical protrusion is disposed on one side surface of the second suction cup, and the second spherical clamping groove is engaged with the second spherical protrusion so that the second fixed base and the second suction cup can rotate relative to each other, and one of the mating surfaces of the second spherical clamping groove and the second spherical protrusion is a concave spherical surface, and the other is a convex spherical surface, and a plurality of second air holes are disposed on a side surface of the second suction cup away from the second spherical protrusion; A second negative pressure device is connected to each of the second air holes.

5. The optical imaging alignment system for chip precision flip-chip bonding according to claim 1, characterized in that: It also includes an optical box, the semi-transparent and semi-reflective plane mirror and the total-reflective plane mirror are arranged in the optical box, the first entrance hole and the second entrance hole are respectively arranged on the two box walls of the optical box that are arranged opposite to each other along the first optical axis, the substrate heating self-balancing fixture is arranged outside the optical box opposite to the first entrance hole, the wafer self-balancing fixture is arranged outside the optical box opposite to the second entrance hole, one of the two box walls of the optical box that are arranged opposite to each other along the second optical axis and is located on the side of the semi-transparent and semi-reflective plane mirror away from the total-reflective plane mirror is provided with an exit hole, and the light receiving end of the imaging device is arranged outside the optical box opposite to the exit hole.

6. The optical imaging alignment system for chip precision flip-chip bonding according to claim 5, characterized in that: The semi-transparent and semi-reflective plane mirror is adjustably arranged in the optical box through a first angle adjustment device, the first angle adjustment device includes a plurality of first telescopic adjustment mechanisms arranged at intervals along the circumference of the semi-transparent and semi-reflective plane mirror, the first telescopic adjustment mechanism includes a first mounting seat, a first threaded sleeve and a first threaded adjustment rod, the first threaded sleeve is rotatably arranged on the first mounting seat around its own axis, the first threaded adjustment rod is threadedly matched with the first threaded sleeve, the first mounting seat and the first threaded adjustment rod are rotatably connected to the semi-transparent and semi-reflective plane mirror and the optical box respectively.

7. The optical imaging alignment system for chip precision flip-chip bonding according to claim 5, characterized in that: The total reflection plane mirror is adjustably arranged in the optical box through a second angle adjustment device, the second angle adjustment device includes a plurality of second telescopic adjustment mechanisms arranged at intervals along the circumference of the total reflection plane mirror, the second telescopic adjustment mechanism includes a second mounting seat, a second threaded sleeve and a second threaded adjustment rod, the second threaded sleeve is rotatably arranged on the second mounting seat around its own axis, the second threaded adjustment rod is threadedly matched with the second threaded sleeve, the second mounting seat and the second threaded adjustment rod are rotatably connected to the total reflection plane mirror and the optical box respectively.

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

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

10. The optical imaging alignment system for chip precision flip-chip bonding according to any one of claims 1 to 9, characterized in that: The imaging device is a telephoto and variable-focus monocular microscope.

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