Offset measurement system and method for flip chip

Abstract

The embodiment of the invention provides a flip chip offset measurement system and method, the measurement system comprises a first light source and a second light source which are different in emergent light beam wavelength, an imaging assembly and a processing assembly, and the first light source is controlled to emit a first light beam which penetrates through a flip chip and irradiates a first target in a deep layer; obtaining a first image containing the first target from the first detector; controlling a second light source to emit a second light beam to irradiate a second target on the surface of the flip chip, acquiring a second image containing the second target from a second detector, and finally acquiring a first offset and a second offset of the flip chip relative to the substrate based on the first image and the second image by a processing assembly, and obtaining the bonding offset of the flip chip according to the first offset and the second offset. According to the invention, the dual-wavelength light source is adopted to cooperatively irradiate the flip chip in a time-sharing / wave-band-sharing manner, so that the penetrability-reflectivity contradiction of single-wavelength detection is broken through, and the accuracy and reliability of lamination offset detection are improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor packaging technology, and in particular to a flip chip offset measurement system and method. Background Art

[0002] Flip chip bonding is an advanced integrated circuit packaging technology that directly connects the chip's electrical connection surface (typically a bump or solder ball array) to a substrate (such as a PCB, ceramic substrate, or silicon interposer) through soldering, conductive adhesive, or other methods to achieve electrical and mechanical connections. Unlike traditional wire bonding, flip chip bonding uses bumps on the chip's underside to achieve a high-density connection to the substrate, eliminating the traditional wire bonding step. This allows for shorter interconnect paths, higher I / O density, and improved electrical performance. It is widely used in high-performance computing, mobile devices, automotive electronics, and other fields.

[0003] The flip-chip bonding process requires high wafer bonding accuracy while ensuring electrical connectivity between wafers. Uniform and consistent bonding offset ensures reliable bonding quality and a secure electrical connection between the upper and lower wafers. However, current chip bonding offset detection technology cannot simultaneously address the alignment requirements for both the chip surface and internal structures, resulting in low offset detection accuracy. Summary of the Invention

[0004] The present application provides a flip chip offset measurement system and method, which can solve the technical problem of low offset detection accuracy in current chip bonding offset detection.

[0005] In a first aspect, embodiments of the present application provide a flip chip offset measurement system, wherein the flip chip is bonded to a substrate and a first target and a second target are provided on the interior and surface of the flip chip, respectively. The offset measurement system includes: The light source assembly includes a first light source and a second light source; the first light source is used to emit a first light beam that penetrates the flip chip and illuminates the first target in a deep layer, and the second light source is used to emit a second light beam that illuminates the second target on the surface of the flip chip; wherein the first light beam and the second light beam emitted by the first light source and the second light source have different wavelengths; an imaging component, configured to capture a first image formed by the first light beam being reflected by the first target, and a second image formed by the second light beam being reflected by the second target; A processing component is used to obtain a first offset of the flip chip relative to the substrate based on the first image, obtain a second offset of the flip chip relative to the substrate based on the second image, and obtain a fitting offset of the flip chip according to the first offset and the second offset.

[0006] In some embodiments, the imaging component includes a first detector and a second detector; the first detector is used to collect the first signal light generated by the first light beam reflected by the first target and form a first image; the second detector is used to collect the second signal light generated by the second light beam reflected by the second target and form a second image.

[0007] In some embodiments, the flip chip offset measurement system further includes an optical component; The optical assembly includes a plurality of optical elements and an objective lens; the plurality of optical elements are used to form a coaxial transmission optical path for the first light beam and the second light beam, so that the first light beam illuminates the first target through the objective lens, or the second light beam illuminates the second target through the objective lens; The plurality of optical elements are further used to form a coaxial transmission optical path of the first signal light and the second signal light, so that the first signal light is transmitted to the first detector through the objective lens, or the second signal light is transmitted to the second detector through the objective lens.

[0008] In some embodiments, the first light beam and the second light beam are incident on the objective lens in a time-sharing manner.

[0009] In some embodiments, the optical assembly includes at least a first optical element, a third optical element, and a fourth optical element, which together constitute a coaxial transmission optical path for the first light beam and the second light beam; the first light beam emitted by the first light source is sequentially reflected by the first optical element and the third optical element, then incident on the objective lens, and then irradiates the first target through the objective lens; the second light beam emitted by the second light source is sequentially reflected by the fourth optical element and the third optical element, then incident on the objective lens, and then irradiates the second target through the objective lens; The optical assembly also includes a fifth optical element and a sixth optical element, which cooperate with the third optical element to form a coaxial transmission optical path for the first signal light and the second signal light; the first signal light generated by reflection from the first target is received by the objective lens, and is sequentially transmitted through the third optical element, and then transmitted or reflected through the fifth optical element to be transmitted to the first detector; the second signal light generated by reflection from the second target is received by the objective lens, and is sequentially transmitted through the third optical element, and then transmitted or reflected through the fifth optical element to be transmitted to the second detector.

[0010] In some embodiments, the optical assembly further comprises a second optical element and / or a sixth optical element; The second optical element is used to reflect the first light beam reflected by the first optical element and the second light beam reflected by the fourth optical element; the sixth optical element is used to reflect the first light beam or the second light beam reflected by the fifth optical element.

[0011] In some embodiments, the first optical element, the fourth optical element and the second optical element are coaxially arranged, and the third optical element and the fifth optical element are coaxially arranged; the fourth optical element is further configured to transmit the first light beam; Among them, the first optical element, the second optical element and the sixth optical element are reflectors; the third optical element is a semi-transparent and semi-reflective mirror; the fourth optical element and the fifth optical element are long-wave dichroic beam splitters or short-wave dichroic beam splitters.

[0012] In some embodiments, the optical assembly includes at least a first optical element, a second optical element, a third optical element, and a fourth optical element, which together constitute a coaxial transmission optical path for the first light beam and the second light beam; the first light beam emitted by the first light source is sequentially reflected by the first optical element, the second optical element, and the third optical element, and then enters the objective lens, and then illuminates the first target through the objective lens; the second light beam emitted by the second light source is sequentially reflected by the fourth optical element, the second optical element, and the third optical element, and then enters the objective lens, and then illuminates the second target through the objective lens; The optical assembly also includes a fifth optical element and a sixth optical element, which cooperate with the third optical element to form a coaxial transmission optical path for the first signal light and the second signal light; the first signal light generated by reflection from the first target is received by the objective lens, and is sequentially projected by the third optical element and reflected by the fifth optical element and the sixth optical element before being transmitted to the first detector; the second signal light generated by reflection from the second target is received by the objective lens, and is sequentially transmitted by the third optical element and the fifth optical element before being transmitted to the second detector.

[0013] In some embodiments, the first optical element, the fourth optical element and the second optical element are coaxially arranged, and the third optical element and the fifth optical element are coaxially arranged; the fourth optical element is further configured to transmit the first light beam; Among them, the first optical element, the second optical element and the sixth optical element are reflectors; the third optical element is a semi-transparent and semi-reflective mirror; the fourth optical element is a long-wave dichroic beam splitter, and the fifth optical element is a short-wave dichroic beam splitter.

[0014] In some embodiments, the angle between the reflective surface of each of the first optical element, the second optical element, the third optical element, the fourth optical element, the fifth optical element, and the sixth optical element and its normal is 45°.

[0015] In some embodiments, the first light source is an infrared light source, and the second light source is a visible light source; the first detector is an infrared camera, and the second detector is a visible light camera.

[0016] In some embodiments, the light source assembly further includes a first modulation unit for modulating the first light beam and a second modulation unit for modulating the second light beam; the imaging assembly further includes a third modulation unit for modulating the first signal light and a fourth modulation unit for modulating the second signal light.

[0017] In some embodiments, a long-wave band-pass filter is provided in front of the first detector, and a short-wave band-pass filter is provided in front of the second detector.

[0018] In a second aspect, an embodiment of the present application provides a method for measuring the offset of a flip chip, wherein the flip chip is bonded to a substrate and a first target and a second target are respectively provided on the interior and the surface of the flip chip, and the first target and the second target are located on the same side of the flip chip; The offset measurement method includes: Controlling the first light source to emit a first light beam to penetrate the flip chip and illuminate the first target in a deep layer, and acquiring a first image including the first target from a first detector; Controlling a second light source to emit a second light beam to illuminate a second target on the surface of the flip chip, and acquiring a second image including the second target from a second detector; wherein the first light source is an infrared light source and the second light source is a visible light source; acquiring a first offset of the flip chip relative to the substrate based on the first image, and acquiring a second offset of the flip chip relative to the substrate based on the second image; The bonding offset of the flip chip is obtained according to the first offset and the second offset.

[0019] In some embodiments, obtaining a first offset of the flip chip relative to the substrate based on the first image includes: performing morphological denoising on the first image; Determining the optimal matching position between the denoised first image and the predefined template according to the predefined template; wherein the predefined template includes at least one sub-image having the same shape or pattern as the first target; determining first coordinates of the first target based on the best matching position; A first offset of the flip chip relative to the substrate is determined according to the first coordinate.

[0020] In some embodiments, determining the best matching position between the denoised first image and the predefined template according to the predefined template includes: Slide the predefined template and compare it pixel by pixel with the denoised first image; Calculating the similarity between the denoised first image and a sub-image on a predefined template; The position with the highest similarity is used as the best matching position between the denoised first image and the predefined template.

[0021] In some embodiments, obtaining a second offset of the flip chip relative to the substrate based on the second image includes: performing sub-pixel edge detection on the second image to obtain pixel grayscale distribution of the second image; determining second coordinates of the second target based on a pixel grayscale distribution of the second image; A second offset of the flip chip relative to the substrate is determined according to the second coordinate.

[0022] In some embodiments, the flip chip offset measurement method described in any embodiment of the second aspect is applied to the flip chip offset measurement system described in any embodiment of the first aspect.

[0023] The flip chip offset measurement system and method provided in the embodiments of the present application utilize a dual-wavelength light source to collaboratively illuminate the flip chip in a time-sharing / band-sharing manner. This utilizes long-wavelength light to penetrate the chip material and directly reach a first target deep within the chip, while simultaneously utilizing short-wavelength light with high reflectivity to illuminate a second target on the surface. After the imaging component acquires the double-layer reflection images in separate channels, the processing component uses a multimodal data fusion algorithm to comprehensively analyze the deep and surface offsets to achieve measurement of the flip chip's fit offset. This application effectively addresses the technical limitations of conventional short-wavelength light, which cannot reach the internal markings of the chip, and the blurred imaging caused by the low reflectivity of long-wavelength light on the surface markings. It also overcomes the penetration-reflectivity contradiction of single-wavelength detection, and achieves high-precision three-dimensional measurement of chip-substrate fit offset, significantly improving the accuracy, reliability, and anti-interference capability of fit offset detection, providing a more comprehensive quality control approach for high-density packaging processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0025] Figure 1A schematic diagram of a flip-chip packaged chip structure; Figure 2 A schematic structural diagram of a flip chip offset measurement system provided by an embodiment of the present application; Figure 3 A schematic structural diagram of a flip chip offset measurement system provided by another embodiment of the present application; Figure 4 A schematic structural diagram of an optical assembly provided in one embodiment of the present application; Figure 5 A schematic structural diagram of an optical assembly provided in another embodiment of the present application; Figure 6 A schematic structural diagram of a flip chip offset measurement system provided by another embodiment of the present application; Figure 7 A flowchart of a method for measuring the offset of a flip chip provided in one embodiment of the present application; Figure 8 A flowchart of a method for measuring the offset of a flip chip provided in another embodiment of the present application; Figure 9 This is a flow chart of a method for measuring the offset of a flip chip provided in yet another embodiment of the present application.

[0026] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0027] The present application is further described in detail below by means of specific embodiments in conjunction with the accompanying drawings. Similar elements in different embodiments are numbered with associated similar elements. In the following embodiments, many detailed descriptions are provided to enable the present application to be better understood. However, those skilled in the art will readily appreciate that some of the features may be omitted in different circumstances, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the present application are not shown or described in the specification. This is to avoid the core portion of the present application being overwhelmed by excessive descriptions. For those skilled in the art, it is not necessary to describe these related operations in detail. They can fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0028] In addition, the features, operations, or characteristics described in the specification may be combined in any appropriate manner to form various embodiments. Furthermore, the steps or actions in the method description may be reordered or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various sequences in the specification and drawings are provided solely for the purpose of clearly describing a particular embodiment and are not intended to be mandatory, unless otherwise specified.

[0029] The terms "first," "second," and so on, in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of this application can be implemented in an order other than that illustrated or described herein. Furthermore, the objects distinguished by "first," "second," and so on generally refer to a class and do not limit the number of objects. For example, the first object can be one or more. Furthermore, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the objects connected are in an "or" relationship. The terms "connection" and "coupling" used in this application, unless otherwise specified, include both direct and indirect connections (couplings).

[0030] The flip-chip bonding process is a high-density, high-performance semiconductor packaging technology. This involves inverting the active surface of the chip and bonding it directly to the substrate, using solder bumps to achieve electrical connection and mechanical fixation. In the flip-chip bonding process, wafer height consistency is a key prerequisite for ensuring bonding quality. Ideally, all solder bumps are of the same height and contact the substrate simultaneously during bonding, forming uniform solder joints. However, if there are height variations on the wafer surface (such as uneven bump height or wafer warpage), if high bumps prematurely contact the substrate during bonding, the substrate will be subjected to excessive pressure, potentially leading to solder extrusion and short circuits. If low bumps do not fully contact the substrate, cold solder joints and open circuits may occur, ultimately affecting device reliability and yield.

[0031] It should be noted that the current flip-chip bonding offset detection technology often uses a single detection method, which results in low offset detection accuracy. For example, visible light imaging technology is used for offset detection. However, since there is a silicon layer or metal layer on the outside of the bonding part of the chip and the substrate, and visible light cannot penetrate the silicon layer or the metal layer, it can only identify the surface marks of the chip, but cannot penetrate the silicon layer to detect the internal or back marks, and cannot meet the packaging and bonding alignment requirements of multi-layer chips. For example, when using infrared imaging technology for offset detection, although infrared light (wavelength>1100nm) can penetrate the silicon layer, the reflectivity of the metal marks on the chip surface is low, and the imaging resolution is limited by the infrared sensor pixel size (usually>5μm) and the target surface size, and cannot meet the requirements. The technical solution of the present application can overcome the problem of low detection accuracy of the existing technology, and adopts a set of optical structures to achieve alignment between the chip surface and the internal structure, thereby improving the offset detection accuracy.

[0032] Figure 1 Figure 1 is a schematic diagram of a flip-chip packaged chip structure. Figure 1 As shown, the flip-chip packaged chip includes a plurality of micro-grain units, and adjacent micro-grain units are electrically isolated by a heat conduction channel filled with high thermal conductivity insulating ceramic. Each micro-grain unit includes a sapphire substrate 1, an N-type nitride layer 2, a light-emitting layer 3, a P-type nitride layer 4, a reflective layer 5, a P-type electrode 10, an N-type electrode 9 and a passivation layer 8 grown in sequence on the sapphire substrate 1, and the micro-grain units are connected in series or / and in parallel through metal wiring on the substrate 12; the N-type electrode 9 is located on the substrate. The thin rectangular structure on plate 12 is composed of a zigzag strip structure that penetrates reflective layer 5, P-type nitride layer 4, and light-emitting layer 3 and connects to N-type nitride layer 2. The N-type electrode is a zigzag strip structure when viewed from above, and a comb-like structure when viewed in section. N-type electrode 9 is electrically isolated from reflective layer 5, P-type nitride layer 4, light-emitting layer 3, and P-type electrode 10 by passivation layer 8. N-type electrode 9 is connected to N-type nitride layer 2, and P-type electrode 10 is connected to P-type nitride layer 4 through reflective layer 5. High thermal conductivity insulating ceramics are made of high thermal conductivity ceramic materials such as aluminum nitride (AlN) ceramics or silicon carbide (SiC) ceramics.

[0033] Based on the above, it can be seen that while achieving electrical connection between wafers, the wafer bonding accuracy is very high. Before flip chip bonding and packaging, the offset of the flip chip needs to be measured to ensure the uniformity and consistency of the bonding offset during packaging. Figure 1As shown, there is a silicon layer or metal layer on the outside of the bonding area between the chip and the substrate. Traditional offset detection is achieved by using visible light imaging technology, but visible light cannot penetrate the silicon layer or metal layer and can only identify the surface marks of the chip. It cannot penetrate the silicon layer to detect the internal or back marks, and cannot meet the packaging and bonding alignment requirements of multi-layer chips. Another method is to use infrared imaging technology. Although infrared light can penetrate the silicon layer, the reflectivity of the metal marks on the chip surface is low, and the imaging resolution is also limited by the pixel size of the infrared sensor and the target surface size. This method cannot meet the requirements.

[0034] This application proposes a flip chip offset measurement system and method, which integrates the imaging advantages of infrared and visible light to achieve synchronous or time-sharing recognition of chip surface and internal marks, and realize accurate measurement of the offset of the flip chip.

[0035] The following specific embodiments describe in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0036] Figure 2 This is a schematic diagram of the structure of a flip chip offset measurement system provided by an embodiment of the present application. Figure 2 As shown, the flip chip offset measurement system provided in this embodiment is used to measure the offset of a flip chip. The flip chip is bonded to a substrate, and a first target and a second target are respectively provided inside and on the surface of the flip chip. The flip chip offset measurement system includes at least a light source component, an imaging component, and a processing component 230.

[0037] In this embodiment, the light source assembly includes a first light source 2101 and a second light source 2102, wherein the first light source 2101 is used to emit a first light beam that penetrates the flip chip and illuminates the first target in the deep layer, and the second light source 2102 is used to emit a second light beam that illuminates the second target on the surface of the flip chip; wherein the wavelengths of the first light beam and the second light beam emitted by the first light source 2101 and the second light beam 2102 are different. In other words, the first light beam emitted by the first light source 2101 can penetrate the silicon layer or metal layer outside the bonding area between the chip and the substrate and reach the first target set in the deep layer of the flip chip, while the second light beam emitted by the second light source 2102 can illuminate the second target set on the surface of the flip chip. At the same time, considering that the first light beam has good reflectivity after penetrating the silicon layer or metal layer, while the second light beam only needs to have good reflectivity for the second target set on the surface, the wavelengths of the first light beam and the second light beam emitted by the first light source 2101 and the second light beam 2102 are different.

[0038] In some embodiments, the first light source 2101 can be infrared light, X-rays, or gamma rays, all of which can penetrate the metal layer or silicon layer on the outer layer of the chip. In practice, X-rays and gamma rays may cause physical reactions when irradiating memory chips, potentially causing electrical failure of the memory chips, and have certain radioactivity and high cost, so they are not considered the optimal choice. The second light source 2102 uses visible light, which has a high reflectivity on the metal markings on the chip surface and is relatively low in cost, and is considered the optimal choice.

[0039] In this embodiment, the imaging component is arranged on the reflection light path of the first light beam reflected by the first target, and on the reflection light path of the second light beam reflected by the second target. The imaging component is used to collect a first image formed by the first light beam reflected by the first target and a second image formed by the second light beam reflected by the second target. The first image and the second image will be used as the basis for calculating the flip chip bonding offset.

[0040] In some embodiments, the imaging component includes a first detector 2201 and a second detector 2202, wherein the first detector 2201 is used to collect the first signal light generated by the first light beam reflected by the first target and form a first image, and the second detector 2202 is used to collect the second signal light generated by the second light beam reflected by the second target and form a second image.

[0041] In some embodiments, the first detector 2201 and the second detector 2202 are photodetectors, CCD cameras, or CMOS sensors. Since the first detector 2201 is used to capture the first signal light reflected by the first light beam, and the second detector 2202 is used to capture the second signal light reflected by the second light beam, the spectral response characteristics of the first detector 2201 cover the wavelength band of the first light beam emitted by the first light source 2101. Similarly, the spectral response characteristics of the second detector 2202 cover the wavelength band of the second light beam emitted by the second light source 2102.

[0042] In some embodiments, when the first light source 2101 is an infrared light source, the first detector 2201 is an infrared camera; when the second light source 2102 is a visible light source, the second detector 2202 is a visible light camera.

[0043] In this embodiment, the processing component 230 is used to obtain a first offset of the flip chip relative to the substrate based on the first image, obtain a second offset of the flip chip relative to the substrate based on the second image, and obtain a bonding offset of the flip chip based on the first offset and the second offset.

[0044] It can be understood that the processing component 230 is used to receive the first image and the second image transmitted by the first detector 2201 and the second detector 2202. Based on the first target information carried by the first image and the second target information carried by the second image, the offset of the first target relative to the substrate, that is, the first offset of the flip chip relative to the substrate, and the offset of the second target relative to the base, that is, the second offset of the flip chip relative to the substrate can be obtained. Further, based on the first offset and the second offset, the fitting offset of the flip chip to the substrate can be obtained.

[0045] In summary, the flip chip offset measurement system provided in this embodiment utilizes a dual-wavelength light source to collaboratively illuminate the flip chip in time and bands. This system utilizes long-wavelength light to penetrate the chip material directly to a first target deep within the chip, while simultaneously utilizing short-wavelength light with high reflectivity to illuminate a second target on the surface. After the imaging component acquires the dual-layer reflection images in separate channels, the processing component uses a multimodal data fusion algorithm to comprehensively analyze the deep and surface offsets to measure the flip chip's fit offset. This measurement system effectively addresses the technical limitations of conventional short-wavelength light, which cannot reach internal chip markings, and the fuzzy imaging caused by the low reflectivity of long-wavelength light on surface markings. It also overcomes the penetration-reflectivity contradiction inherent in single-wavelength detection, enabling high-precision three-dimensional measurement of chip-substrate fit offsets. This significantly improves the accuracy, reliability, and anti-interference capability of fit offset detection, providing a more comprehensive quality control approach for high-density packaging processes.

[0046] Figure 3 This is a schematic diagram of the structure of a flip chip offset measurement system provided by another embodiment of the present application. Figure 3 As shown, the flip chip offset measurement system provided in this embodiment, based on any of the above embodiments, includes, in addition to the light source component, the imaging component and the processing component 230 , an optical component 240 .

[0047] In this embodiment, the optical assembly 240 includes a plurality of optical elements and an objective lens 2407, which are used to form a transmission optical path for the first light beam and the second light beam. Specifically, the plurality of optical elements are used to form a coaxial transmission optical path for the first light beam and the second light beam, so that the first light beam illuminates the first target through the objective lens 2407, or the second light beam illuminates the second target through the objective lens 2407; and to form a coaxial transmission optical path for the first signal light and the second signal light, so that the first signal light is transmitted to the first detector 2201 through the objective lens 2407, or the second signal light is transmitted to the second detector 2202 through the objective lens 2407.

[0048] In some embodiments, when the optical assembly 240 includes only one objective lens 2407 , the first light beam and the second light beam are incident on the objective lens 2407 in a time-sharing manner.

[0049] As can be understood, the time-sharing incident signal of the first and second light beams on objective lens 2407 effectively avoids signal aliasing caused by interference, scattering, or nonlinear detector response when light beams of different wavelengths or polarization states are incident simultaneously. This also simplifies system complexity, reduces requirements for detector bandwidth and dynamic range, and enables simultaneous multi-parameter measurement in dynamic scenarios. Therefore, temporal isolation eliminates crosstalk and interference between the first and second light beams, improving the imaging system's signal-to-noise ratio, dynamic range, and measurement accuracy, ultimately facilitating higher-resolution, lower-noise imaging.

[0050] Figure 4 This is a schematic diagram of the structure of an optical component provided by an embodiment of the present application. Figure 4 As shown, the optical assembly 240 provided in this embodiment includes at least a first optical element 2401 , a second optical element 2402 , a third optical element 2403 , a fourth optical element 2404 , a fifth optical element 2405 and a sixth optical element 2406 .

[0051] Specifically, the first optical element 2401, the second optical element 2402, the third optical element 2403, and the fourth optical element 2404 together form a coaxial transmission optical path for the first and second light beams. The first light beam emitted by the first light source 2101 is sequentially reflected by the first optical element 2401, the second optical element 2402, and the third optical element 2403 before entering the objective lens 2407 and irradiating the first target through the objective lens 2407. The second light beam emitted by the second light source 2102 is sequentially reflected by the fourth optical element 2404, the second optical element 2402, and the third optical element 2403 before entering the objective lens 2407 and irradiating the second target through the objective lens 2407.

[0052] The fifth optical element 2405 and the sixth optical element 2406 cooperate with the third optical element 2403 to form a coaxial transmission optical path for the first signal light and the second signal light; the first signal light generated by reflection from the first target is received by the objective lens 2407, and is transmitted to the first detector 2201 after being sequentially transmitted through the third optical element 2403 and the fifth optical element 2405; the second signal light generated by reflection from the second target is received by the objective lens 2407, and is sequentially transmitted through the third optical element 2403, reflected by the fifth optical element 2405, and reflected by the sixth optical element 2406, and is transmitted to the second detector 2202.

[0053] It should be noted that the purpose of providing the second optical element 2402 and the sixth optical element 2406 is to enable light, which would otherwise have to travel a long distance in a straight line to reach its target location, to instead bend and travel at a specific angle after being reflected by the reflector. This effectively folds the optical path structure without changing the optical performance of the light, optimizing the optical path layout. This helps reduce the overall physical size of the system or accommodate specific spatial installation constraints, thereby achieving efficient transmission of optical signals within limited spaces. Therefore, in optical path layouts different from the above-described embodiment, the second optical element 2402 and the sixth optical element 2406 may be omitted.

[0054] In some embodiments, to further shorten the beam propagation path and ensure coaxial transmission of the first and second beams, the first optical element 2401, the fourth optical element 2404, and the second optical element 2402 are coaxially arranged in a vertical direction, and the third optical element 2403 and the fifth optical element 2405 are coaxially arranged in a vertical direction. In this case, the fourth optical element 2404 is also used to receive the first beam reflected by the first optical element 2401 and transmit it to the second optical element 2402.

[0055] In some embodiments, the first optical element 2401 and the sixth optical element 2406 are coaxially arranged in the horizontal direction.

[0056] In some embodiments, the first optical element 2401, the second optical element 2402 and the sixth optical element 2406 are reflectors; the third optical element 2403 is a semi-transparent and semi-reflective mirror; the fourth optical element 2404 and the fifth optical element 2405 are long-wave dichroic spectrometers, that is, the fourth optical element 2404 and the fifth optical element 2405 can transmit the first light beam with a longer wavelength and reflect the second light beam with a shorter wavelength.

[0057] Figure 5 This is a schematic diagram of the structure of an optical component provided in another embodiment of the present application. Figure 5 As shown, the optical assembly 240 provided in this embodiment includes at least a first optical element 2401 , a second optical element 2402 , a third optical element 2403 , a fourth optical element 2404 , a fifth optical element 2405 and a sixth optical element 2406 .

[0058] Specifically, the first optical element 2401, the second optical element 2402, the third optical element 2403 and the fourth optical element 2404 constitute a coaxial transmission optical path for the first light beam and the second light beam; the first light beam emitted by the first light source 2101 is reflected by the first optical element 2401, the second optical element 2402 and the third optical element 2403 in sequence, and then enters the objective lens 2407, and irradiates the first target through the objective lens 2407; the second light beam emitted by the second light source 2102 is reflected by the fourth optical element 2404, the second optical element 2402 and the third optical element 2403 in sequence, and then enters the objective lens 2407, and then irradiates the second target through the objective lens 2407.

[0059] The fifth optical element 2405 and the sixth optical element 2406 cooperate with the third optical element 2403 to form a coaxial transmission optical path for the first signal light and the second signal light; the first signal light generated by reflection from the first target is received by the objective lens 2407, and is sequentially projected by the third optical element 2403 and reflected by the fifth optical element 2405 and the sixth optical element 2406 before being transmitted to the first detector 2201; the second signal light generated by reflection from the second target is received by the objective lens 2407, and is sequentially transmitted by the third optical element 2403 and the fifth optical element 2405 before being transmitted to the second detector 2202.

[0060] As described above, in an optical path layout different from that of this embodiment, the second optical element 2402 and the sixth optical element 2406 may also be omitted.

[0061] In some embodiments, to shorten the beam propagation path and ensure coaxial transmission of the first and second beams, the first optical element 2401, the fourth optical element 2404, and the second optical element 2402 are coaxially arranged in a vertical direction, and the third optical element 2403 and the fifth optical element 2405 are coaxially arranged in a vertical direction. In this case, the fourth optical element 2404 is also used to receive the first beam reflected by the first optical element 2401 and transmit it to the second optical element 2402.

[0062] In some embodiments, the first optical element 2401 and the sixth optical element 2406 are coaxially arranged in the horizontal direction.

[0063] In some embodiments, the first optical element 2401, the second optical element 2402 and the sixth optical element 2406 are reflectors; the third optical element 2403 is a semi-transparent mirror; the fourth optical element 2404 is a long-wave dichroic beam splitter; and the fifth optical element 2405 is a short-wave dichroic beam splitter.

[0064] Figure 5 The optical assembly 240 shown is similar to the above embodiment ( Figure 4) is that the fourth optical element 2404 is configured as a long-wavelength dichroic beam splitter, that is, the fourth optical element 2404 can transmit the first light beam with a longer wavelength and reflect the second light beam with a shorter wavelength. The fifth optical element 2405 is configured as a short-wavelength dichroic beam splitter, that is, the fifth optical element 2405 can reflect the first light beam with a longer wavelength and transmit the second light beam with a shorter wavelength.

[0065] In some embodiments, based on the structure of the optical component 240 of any of the above embodiments, the angle between the reflective surface of each of the first optical element 2401, the second optical element 2402, the third optical element 2403, the fourth optical element 2404, the fifth optical element 2405 and the sixth optical element 2406 and its own normal is 45°, so as to achieve coaxial transmission of the first light beam and the second light beam, and can utilize the symmetry of mirror reflection or the splitter film to separate the incident light and the reflected light path at 90 degrees, thereby simplifying the system structure and reducing space occupancy, and can also balance the reflection / transmission efficiency of the splitter film, ultimately achieving compact, stable and multifunctional optical path control.

[0066] Figure 6 This is a schematic diagram of the structure of a flip chip offset measurement system provided by another embodiment of the present application. Figure 6 As shown, the flip chip offset measurement system provided in this embodiment, based on any of the above embodiments, further includes a modulation unit and a filtering unit for modulating the first light beam and the second light beam.

[0067] In some embodiments, the light source assembly includes a first modulation unit 2103 for modulating the first light beam and a second modulation unit 2104 for modulating the second light beam.

[0068] Among them, the first modulation unit 2103 and the second modulation unit 2104 are respectively arranged on the outgoing light path of the first light source 2101 and the outgoing light path of the second light source 2102, and are used to dynamically adjust the first light beam and the second light beam, including intensity modulation, phase modulation, wavelength / frequency modulation and / or polarization state modulation of the light beam, so as to realize encoding, modulation or wavelength control of the first light beam and the second light beam, and provide customized light input for the subsequent optical system, so that the first detector 2201 and the second detector 2202 can capture clearer first and second images.

[0069] In some embodiments, the imaging component includes a third modulation unit 2203 for modulating the first signal light and a fourth modulation unit 2204 for modulating the second signal light.

[0070] Among them, the third modulation unit 2203 and the fourth modulation unit 2204 are respectively arranged at the front end of the first detector 2201 and the second detector 2202, and are used to dynamically adjust the characteristics of the first signal light and the second signal light before the optical signal reaches the detector, including polarization control, phase compensation and light intensity balance, so as to improve the imaging quality of the detector and suppress noise.

[0071] In some embodiments, a long-wave bandpass filter is provided in front of the first detector 2201, and a short-wave bandpass filter is provided in front of the second detector 2202, which are used to selectively transmit light signals in a specific wavelength range while suppressing interference from other wavelengths, thereby optimizing the signal-to-noise ratio of the detector and improving system performance.

[0072] Figure 7 This is a flow chart of a method for measuring the offset of a flip chip provided by an embodiment of the present application. Figure 7 As shown, the flip chip offset measurement method provided in this embodiment includes the following steps: a flip chip is bonded to a substrate and a first target and a second target are provided on the interior and surface of the flip chip, respectively, and the first target and the second target are located on the same side of the flip chip. Step S710: Control the first light source to emit a first light beam to penetrate the flip chip and illuminate the first target at a deep layer, and obtain a first image including the first target from the first detector.

[0073] Step S720: Control the second light source to emit a second light beam to illuminate a second target on the surface of the flip chip, and obtain a second image containing the second target from the second detector; wherein the first light source is an infrared light source and the second light source is a visible light source.

[0074] It should be noted that in steps S710 and S720, controlling the first light source 2101 and the second light source 2102 to illuminate the flip chip can be performed in a time-sharing manner or simultaneously. Generally, time-sharing control of the first light source 2101 and the second light source 2102 can effectively avoid signal aliasing caused by interference, scattering, or nonlinear detector response when light beams of different wavelengths or polarization states are simultaneously incident, eliminate crosstalk and interference between the first light beam and the second light beam, improve the signal-to-noise ratio, dynamic range, and measurement accuracy of the imaging system, and ultimately achieve higher resolution and lower noise imaging effects.

[0075] Step S730: Acquire a first offset of the flip chip relative to the substrate based on the first image, and acquire a second offset of the flip chip relative to the substrate based on the second image.

[0076] Step S740: Obtain the flip chip bonding offset according to the first offset and the second offset.

[0077] It is understood that the offset measurement method can be configured in the processing component 230 of the offset measurement system, which includes at least a light source component and an imaging component. The light source component includes a first light source 2101 and a second light source 2102, wherein the first light source 2101 is an infrared light source and the second light source 2102 is a visible light source. In other words, the first light beam emitted by the first light source 2101 can penetrate the silicon layer or metal layer outside the bonding area between the chip and the substrate and reach the first target disposed deep inside the flip chip, while the first light beam emitted by the second light source 2102 can reach the second target on the surface of the chip. The imaging component includes a first detector 2201 and a second detector 2202. The first detector 2201 is used to collect the first signal light generated by the first light beam reflected from the first target and form a first image, and the second detector 2202 is used to collect the second signal light generated by the second light beam reflected from the second target and form a second image.

[0078] After receiving the first image and the second image transmitted by the first detector 2201 and the second detector 2202, the processing component 230 of the offset measurement system can obtain the offset of the first target relative to the substrate, that is, the first offset of the flip chip relative to the substrate, and the offset of the second target relative to the base, that is, the second offset of the flip chip relative to the substrate, based on the first target information carried by the first image and the second target information carried by the second image. Further, based on the first offset and the second offset, the fitting offset of the flip chip to the substrate can be obtained.

[0079] The flip chip offset measurement method provided in this embodiment adopts a dual-wavelength light source to collaboratively illuminate the flip chip in time-sharing / band-sharing manner, that is, long-wavelength light is used to penetrate the chip material directly to reach the deep first target, while short-wavelength light with high reflectivity is used to illuminate the surface second target. Combined with a multimodal data fusion algorithm, the method comprehensively analyzes the deep and surface offsets, significantly improving the accuracy, reliability and anti-interference ability of the fitting offset detection, and providing a more comprehensive quality control method for high-density packaging processes.

[0080] Figure 8 This is a flow chart of a method for measuring the offset of a flip chip provided by another embodiment of the present application. Figure 8 As shown, based on the above embodiment, in step S730, obtaining a first offset of the flip chip relative to the substrate based on the first image specifically includes: Step S810: Perform morphological denoising on the first image.

[0081] Step S820: Determine the best matching position between the denoised first image and the predefined template according to the predefined template; wherein the predefined template includes at least one sub-image having the same shape or pattern as the first target.

[0082] In some embodiments, determining the best matching position between the denoised first image and the predefined template according to the predefined template includes: Step S8201: Slide the predefined template and compare it pixel by pixel with the denoised first image; Step S8202: Calculate the similarity between the denoised first image and the sub-image on the predefined template; Step S8203: The position with the highest similarity is used as the best matching position between the denoised first image and the predefined template.

[0083] Step S830: Determine the first coordinates of the first target based on the best matching position.

[0084] Step S840: Determine a first offset of the flip chip relative to the substrate according to the first coordinate.

[0085] It can be understood that before obtaining the first offset of the flip chip relative to the substrate based on the first image, first, the first image is subjected to morphological denoising, such as opening and closing operations, to eliminate noise caused by tiny particles, scratches or uneven lighting on the chip surface, improve image quality, and lay the foundation for subsequent precise matching; then, based on a predefined template containing a sub-image with the same shape or pattern as the first target, the template and the denoised image are compared pixel by pixel through a sliding window, and the similarity between the two is calculated (such as normalized cross correlation NCC, structural similarity SSIM and other indicators), and finally the area with the highest similarity is located as the best matching position, and then the first coordinate of the target in the image coordinate system is extracted; finally, based on the mapping relationship between the first coordinate of the target and the substrate reference coordinate system (which can be obtained through the coordinate transformation matrix), the actual offset of the flip chip relative to the substrate is calculated, such as the X / Y direction displacement and rotation angle.

[0086] Figure 9 This is a flow chart of a method for measuring the offset of a flip chip provided in another embodiment of the present application. Figure 9 As shown, based on the above embodiment, in step S730, obtaining a second offset of the flip chip relative to the substrate based on the second image specifically includes: Step S910: Perform sub-pixel edge detection on the second image to obtain pixel grayscale distribution of the second image.

[0087] Step S920: Determine the second coordinates of the second target based on the pixel grayscale distribution of the second image.

[0088] Step S930: Determine a second offset of the flip chip relative to the substrate according to the second coordinate.

[0089] It can be understood that before obtaining the first offset of the flip chip relative to the substrate based on the first image, sub-pixel edge detection is first performed on the second image. By analyzing the grayscale gradient changes of the pixel-level edge, the edge positioning accuracy is improved to the sub-pixel level, so as to capture the subtle features of the target edge and generate a high-precision pixel grayscale distribution map, providing richer detail information for subsequent coordinate calculations; secondly, based on the grayscale distribution map, the center coordinates of the second target are determined using a geometric fitting method (such as least squares fitting of a circle or a straight line), and the second coordinates are converted into the actual physical offset of the flip chip relative to the substrate.

[0090] In summary, by combining the first offset calculation method of morphological denoising and template matching with the second offset calculation method based on sub-pixel edge detection and grayscale distribution fitting, the overall performance of flip-chip offset measurement can be significantly improved. The former ensures the robustness of target positioning through denoising and template matching, effectively suppressing the impact of image noise and local distortion on the measurement results; the latter improves positioning accuracy to the micron level using sub-pixel edge detection, while further enhancing anti-interference capabilities based on geometric fitting of grayscale distribution. The two methods work together to ensure the stability and repeatability of measurement results while achieving a balance between high precision and high efficiency. Ultimately, they provide a reliable quality control method for the flip-chip packaging process and significantly reduce the yield loss caused by offset deviations.

[0091] It should be noted that the flip chip offset measurement method provided in any of the above embodiments can be applied to the above embodiments. Figure 1-6 In the flip chip offset measurement system described in any embodiment, the steps of the flip chip offset measurement method of any embodiment described above can be implemented in the processing component 230 of the flip chip offset measurement system by the processing component 230 or the processor in the processing component 230.

[0092] In some embodiments, the offset measurement method for a flip chip provided in any of the above embodiments may be configured in a computer storage medium or a computer program product. The computer storage medium or the computer program product stores a program or instruction. When the program or instruction is executed by a processor, the various processes of any embodiment of the offset measurement method for a flip chip as described above can be implemented, and the same technical effect can be achieved. To avoid repetition, it will not be described here.

[0093] The processor may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application. The readable storage medium includes a computer-readable storage medium, such as a computer read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0094] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can make several simple deductions, modifications or replacements based on the ideas of the present application without departing from the scope of protection of the purpose of the present application and the claims. All of these are within the protection of the present application.

Claims

1. A flip chip offset measurement system, characterized in that: The flip chip is used to be attached to a substrate, and a first target and a second target are respectively provided inside and on a surface of the flip chip. The offset measurement system includes: The light source assembly includes a first light source and a second light source; the first light source is used to emit a first light beam that penetrates the flip chip and illuminates the first target in a deep layer, and the second light source is used to emit a second light beam that illuminates the second target on the surface of the flip chip; wherein the first light beam and the second light beam emitted by the first light source and the second light source have different wavelengths; an imaging component, configured to capture a first image formed by the first light beam being reflected by the first target, and a second image formed by the second light beam being reflected by the second target; A processing component is used to obtain a first offset of the flip chip relative to the substrate based on the first image, obtain a second offset of the flip chip relative to the substrate based on the second image, and obtain a fitting offset of the flip chip according to the first offset and the second offset.

2. The flip chip offset measurement system according to claim 1, wherein: The imaging assembly includes a first detector and a second detector; the first detector is used to collect the first signal light generated by the first light beam reflected by the first target and form a first image; the second detector is used to collect the second signal light generated by the second light beam reflected by the second target and form a second image.

3. The flip chip offset measurement system according to claim 2, wherein: Also included are optical components; The optical assembly includes a plurality of optical elements and an objective lens; the plurality of optical elements are used to form a coaxial transmission optical path for the first light beam and the second light beam, so that the first light beam illuminates the first target through the objective lens, or the second light beam illuminates the second target through the objective lens; The plurality of optical elements are further used to form a coaxial transmission optical path of the first signal light and the second signal light, so that the first signal light is transmitted to the first detector through the objective lens, or the second signal light is transmitted to the second detector through the objective lens.

4. The flip chip offset measurement system according to claim 3, wherein: The first light beam and the second light beam are incident on the objective lens in a time-division manner.

5. The flip chip offset measurement system according to claim 3, wherein: The optical assembly comprises at least a first optical element, a third optical element, and a fourth optical element, which together form a coaxial transmission optical path for the first light beam and the second light beam; the first light beam emitted by the first light source is reflected by the first optical element and the third optical element in sequence, and then enters the objective lens, and then illuminates the first target through the objective lens; The second light beam emitted by the second light source is reflected by the fourth optical element and the third optical element in sequence and then enters the objective lens, and then illuminates the second target through the objective lens; The optical assembly further includes a fifth optical element, which cooperates with the third optical element to form a coaxial transmission optical path for the first signal light and the second signal light; the first signal light generated by reflection from the first target is received by the objective lens, and is sequentially transmitted through the third optical element, and then transmitted or reflected through the fifth optical element to be transmitted to the first detector; The second signal light generated after being reflected by the second target is received by the objective lens, sequentially transmitted through the third optical element, and then reflected or transmitted through the fifth optical element before being transmitted to the second detector.

6. The flip chip offset measurement system according to claim 5, wherein: The optical assembly further comprises a second optical element and / or a sixth optical element; The second optical element is used to reflect the first light beam reflected by the first optical element and the second light beam reflected by the fourth optical element; The sixth optical element is used to reflect the first light beam or the second light beam reflected by the fifth optical element.

7. The flip chip offset measurement system according to claim 6, wherein: The first optical element, the fourth optical element and the second optical element are coaxially arranged, and the third optical element and the fifth optical element are coaxially arranged; the fourth optical element is further used to transmit the first light beam; Among them, the first optical element, the second optical element and the sixth optical element are reflectors; the third optical element is a semi-transparent and semi-reflective mirror; the fourth optical element and the fifth optical element are long-wave dichroic beam splitters or short-wave dichroic beam splitters.

8. The flip chip offset measurement system according to any one of claims 5 to 7, characterized in that: The angle between the reflective surface of each of the first optical element, the second optical element, the third optical element, the fourth optical element, the fifth optical element and the sixth optical element and its normal is 45°.

9. The flip chip offset measurement system according to claim 2, wherein: The first light source is an infrared light source, and the second light source is a visible light source; the first detector is an infrared camera, and the second detector is a visible light camera.

10. The flip chip offset measurement system according to claim 2, wherein: The light source assembly further includes a first modulation unit for modulating the first light beam and a second modulation unit for modulating the second light beam; the imaging assembly further includes a third modulation unit for modulating the first signal light and a fourth modulation unit for modulating the second signal light.

11. The flip chip offset measurement system according to claim 2, wherein: A long-wave band-pass filter is provided in front of the first detector, and a short-wave band-pass filter is provided in front of the second detector.

12. A method for measuring the offset of a flip chip, characterized in that: The flip chip is used to be attached to a substrate, and a first target and a second target are respectively provided on the interior and the surface of the flip chip, and the first target and the second target are located on the same side of the flip chip; The offset measurement method includes: Controlling the first light source to emit a first light beam to penetrate the flip chip and illuminate the first target in a deep layer, and acquiring a first image including the first target from a first detector; Controlling a second light source to emit a second light beam to illuminate a second target on the surface of the flip chip, and acquiring a second image including the second target from a second detector; wherein the first light source is an infrared light source and the second light source is a visible light source; acquiring a first offset of the flip chip relative to the substrate based on the first image, and acquiring a second offset of the flip chip relative to the substrate based on the second image; The bonding offset of the flip chip is obtained according to the first offset and the second offset.

13. The flip chip offset measurement method according to claim 12, wherein: The acquiring a first offset of the flip chip relative to the substrate based on the first image includes: performing morphological denoising on the first image; Determining the optimal matching position between the denoised first image and the predefined template according to the predefined template; wherein the predefined template includes at least one sub-image having the same shape or pattern as the first target; determining first coordinates of the first target based on the best matching position; A first offset of the flip chip relative to the substrate is determined according to the first coordinate.

14. The flip chip offset measurement method according to claim 13, wherein: The step of determining the best matching position between the denoised first image and the predefined template according to the predefined template includes: Slide the predefined template and compare it pixel by pixel with the denoised first image; Calculating the similarity between the denoised first image and a sub-image on a predefined template; The position with the highest similarity is used as the best matching position between the denoised first image and the predefined template.

15. The flip chip offset measurement method according to claim 13, wherein: The acquiring a second offset of the flip chip relative to the substrate based on the second image includes: performing sub-pixel edge detection on the second image to obtain pixel grayscale distribution of the second image; determining second coordinates of the second target based on a pixel grayscale distribution of the second image; A second offset of the flip chip relative to the substrate is determined according to the second coordinate. 16 . The method for measuring the offset of a flip chip according to claim 12 , applied to the system for measuring the offset of a flip chip according to claim 1 .

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