Solder post height measurement method, chip tilt angle measurement method, and solder post height measurement system

Abstract

This application provides a method for measuring solder pillar height, a method for measuring chip tilt angle, and a system for measuring solder pillar height. The method involves acquiring an image of the solder pillar distribution of a sample under test, measuring the height of the sample using a height measuring device to obtain the distance between the first surface and the second surface of the substrate facing the chip, and, based on the target position of the target solder pillar in the solder pillar distribution image, controlling an infrared spectrometer to be positioned above the target solder pillar so that the infrared light source in the infrared spectrometer emits a light beam towards the chip. The reflected light from the two surfaces of the chip interferes, obtaining an infrared spectral signal. The chip thickness is determined based on the infrared spectral signal. Based on the distance and chip thickness, the target solder pillar height is determined. This application first quickly and accurately obtains the total height of the chip and solder pillars using a height measuring device, then determines the chip thickness based on the interference information, and finally calculates the solder pillar height. The operation is simple and convenient, and it greatly improves the accuracy of the solder pillar height measurement.

Description

Technical Field

[0001] This application relates to the field of semiconductor measurement, and in particular to a method for measuring solder post height, a method for measuring chip tilt angle, and a system for measuring solder post height. Background Technology

[0002] In the field of chip packaging, chip tilt testing is a core yield factor that determines the success or failure of 3D stacking. Accurately measuring the solder pillar height between the chip and the substrate is crucial for ensuring chip packaging quality and improving the performance of electronic products.

[0003] Currently, tilt testing is commonly performed on upper-layer chips; however, this method ignores the impact of substrate tilt on the chip's tilt angle. Furthermore, existing technologies typically measure solder joint height using white light triangulation or numerical simulation. White light triangulation, by establishing a measurement simulation model or actual measurement system, analyzes the changes in the reflected light spot at the top of the bump during the movement of the sample (composed of the chip and substrate) to measure the solder joint height. However, it is significantly affected by external factors such as ambient light, leading to measurement deviations. Numerical simulation proposes numerical prediction models to predict the final support height of the solder joint, but often results in inaccurate predictions due to inconsistencies between the assumptions and actual conditions.

[0004] Therefore, providing an accurate method for testing chip tilt angle and measuring solder post height has become an urgent problem to be solved. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a method for measuring solder post height, a method for measuring chip tilt angle, and a system for measuring solder post height, which greatly improves the accuracy of measuring solder post height. The specific solution is as follows: On the one hand, this application provides a method for measuring the height of a weld column, including: Acquire a pin distribution image of the sample to be tested, wherein the sample to be tested includes a substrate, a chip, and multiple pins located between the substrate and the chip, and the multiple pins include target pins; The height of the sample under test is measured by a height measuring device to obtain the distance between the first surface of the chip facing away from the substrate and the second surface of the substrate facing the chip. Based on the target position of the target weld post in the weld post distribution image, the infrared spectroscopy device is positioned above the target weld post, so that the infrared light source in the infrared spectroscopy device emits a light beam toward the chip. The reflected light from the light beam on both sides of the chip interferes to obtain an infrared spectral signal. The chip thickness is determined based on the infrared spectral signal; The target bonding pillar height is determined based on the spacing and the chip thickness.

[0006] In one possible implementation, determining the chip thickness based on the infrared spectral signal includes: The infrared spectral signal is converted into a reflectance spectral signal with respect to wavenumber; Perform a Fourier transform on the reflected spectrum signal to obtain the spectrum; The spectrum is processed to find peaks, and the chip thickness is determined based on the thickness coordinates corresponding to the peaks.

[0007] In one possible implementation, measuring the height of the sample under test using a height measuring device to obtain the distance between the first surface of the chip facing away from the substrate and the second surface of the substrate facing the chip includes: Based on the target position of the target weld column in the weld column distribution image, the height measuring device is controlled to be positioned above the target weld column, and the height of the first surface is measured by the height measuring device to obtain the first height between the first surface and the height measuring device. The height measuring device is positioned in an exposed area of ​​the substrate not covered by the chip. The height of the second surface of the exposed area is measured by the height measuring device to obtain a second height between the second surface and the height measuring device. The distance between the first surface and the second surface is determined based on the first height and the second height.

[0008] In one possible implementation, the height measuring device is a white light interferometer or a white light confocal device.

[0009] In one possible implementation, when the height measuring device is a white light interferometer, the step of measuring the height of the first surface using the height measuring device to obtain a first height between the first surface and the height measuring device includes: Incident light is emitted onto the first surface through a white light source in the white light interferometer. The measured reflected light from the first surface interferes with the reference reflected light. The distance between the white light interferometer and the first surface is adjusted until the interference fringes meet the sharpness requirements, and the first height is obtained. The step of measuring the height of the second surface of the exposed area using the height measuring device to obtain a second height between the second surface and the height measuring device includes: Incident light is emitted onto the second surface through a white light source in the white light interferometer. The measured reflected light from the second surface interferes with the reference reflected light. The distance between the white light interferometer and the second surface is adjusted until the interference fringes meet the sharpness requirements, thus obtaining the second height.

[0010] In one possible implementation, acquiring the weld bead distribution image of the sample under test includes: An initial image is obtained by acquiring an image of the first surface of the sample to be tested located on the sample stage using an infrared camera; Based on a preset grayscale threshold, the region where the weld column is located is extracted from the initial image to obtain the weld column distribution image.

[0011] In one possible implementation, the method further includes: A circular fit is performed on the area where the weld column is located in the weld column distribution image to determine the coordinates of the center of the circle relative to the sample stage, thereby obtaining the position of the weld column in the weld column distribution image.

[0012] In another aspect, embodiments of this application also provide a method for measuring chip tilt angle, the method comprising: The first weld column height of the first target weld column and the second weld column height of the second target weld column are determined. The first target weld column and the second target weld column are arranged along the target direction. The first weld column height and the second weld column height are obtained by the weld column height measurement method. Based on the height of the first solder post, the height of the second solder post, and the length of the chip in the target direction, the tilt angle of the chip relative to the substrate in the target direction is determined.

[0013] In another aspect, embodiments of this application also provide a weld column height measurement system, the system comprising: An image acquisition device is used to acquire a pin distribution image of a sample to be tested, the sample to be tested including a substrate, a chip, and multiple pins located between the substrate and the chip, the multiple pins including a target pin; A height measuring device is used to measure the height of the sample to be tested, and to obtain the distance between the first surface of the chip facing away from the substrate and the second surface of the substrate facing the chip. An infrared spectroscopy device is used to emit a light beam toward the chip through an infrared light source in the infrared spectroscopy device. The reflected light from the light beam on both sides of the chip interferes to obtain an infrared spectral signal. The first switching device is used to switch one of the image acquisition device, the height measurement device, and the infrared spectroscopy device to perform the measurement. A computing device is configured to determine the chip thickness of the chip based on the infrared spectral signal, and to determine the target bonding height of the target bonding post based on the spacing and the chip thickness.

[0014] In one possible implementation, the height measuring device is a white light interferometer or a white light confocal device.

[0015] In one possible implementation, the computing device is specifically configured to: convert the infrared spectral signal into a wavenumber-related reflectance spectral signal; perform a Fourier transform on the reflectance spectral signal to obtain a spectrum; perform peak-finding processing on the spectrum, and determine the chip thickness based on the thickness coordinates corresponding to the peaks.

[0016] In one possible implementation, based on the target position of the target weld post in the weld post distribution image, the first switching device moves the sample stage or the height measuring device so that the height measuring device is positioned above the target weld post. The height of the first surface is measured by the height measuring device to obtain a first height between the first surface and the height measuring device. Furthermore, the first switching device moves the sample stage or the height measuring device so that the height measuring device is positioned in an exposed area of ​​the substrate not covered by the chip. The height of the second surface in the exposed area is measured by the height measuring device to obtain a second height between the second surface and the height measuring device. The computing device determines the distance between the first surface and the second surface based on the first height and the second height.

[0017] In one possible implementation, when the height measuring device is a white light interferometer, incident light is emitted from a white light source in the white light interferometer toward the first surface. The measured reflected light from the first surface interferes with the reference reflected light. The first switching device adjusts the distance between the white light interferometer and the first surface until the interference fringes meet the sharpness requirement, thus obtaining the first height. Similarly, incident light is emitted from a white light source in the white light interferometer toward the second surface. The measured reflected light from the second surface interferes with the reference reflected light. The first switching device adjusts the distance between the white light interferometer and the second surface until the interference fringes meet the sharpness requirement, thus obtaining the second height. The calculation device determines the distance between the first and second surfaces based on the first and second heights.

[0018] In one possible implementation, the image acquisition device includes an infrared camera, specifically configured to: acquire an image of the first surface of the sample to be tested located on the sample stage using the infrared camera to obtain an initial image; and extract the area where the weld pillars are located from the initial image based on a preset grayscale threshold to obtain the weld pillar distribution image.

[0019] In one possible implementation, the computing device is specifically configured to: perform circular fitting on the area where the weld column is located in the weld column distribution image, determine the coordinates of the center of the circle relative to the sample stage, and obtain the position of the weld column in the weld column distribution image.

[0020] In one possible implementation, the solder post height measurement system determines a first solder post height of a first target solder post and a second solder post height of a second target solder post by measurement, the first and second target solder posts being arranged along a target direction. The computing device determines the tilt angle of the chip relative to the substrate in the target direction based on the first solder post height, the second solder post height, and the length of the chip in the target direction.

[0021] This application provides a method for measuring solder pillar height, a method for measuring chip tilt angle, and a system for measuring solder pillar height. The method acquires an image of the solder pillar distribution of a sample under test. The sample includes a substrate, a chip, and multiple solder pillars located between the substrate and the chip. These multiple solder pillars include a target solder pillar. To accurately measure the solder pillar height, a height measuring device is first used to measure the height of the sample under test, obtaining the distance between the first surface of the chip facing away from the substrate and the second surface of the substrate facing the chip, which is the total height of the chip and the solder pillars. Next, the chip thickness needs to be accurately determined. Based on the target position of the target solder pillar in the solder pillar distribution image, an infrared spectrometer is positioned above the target solder pillar, causing the infrared light source in the infrared spectrometer to emit a light beam towards the chip. Since infrared light can penetrate the chip but cannot penetrate the solder pillars, the reflected light from the two surfaces of the chip interferes, obtaining an infrared spectral signal. Because the infrared spectral signal carries the interference information of the two surfaces of the chip, the chip thickness is determined based on the infrared spectral signal. Based on the distance and the chip thickness, the target solder pillar height is determined. In summary, this application first uses a height measuring device to quickly and accurately obtain the total height of the chip and the bonding pillars, then determines the chip thickness based on interference information, and finally calculates the height of the bonding pillars. The operation is simple and convenient, and greatly improves the accuracy of the bonding pillar height. Furthermore, the tilt angle of the chip relative to the substrate can be determined by at least two bonding pillar heights and the chip's length in the target direction. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A flowchart illustrating the weld column height measurement method provided in an embodiment of this application is shown. Figure 2 A cross-sectional view of the sample to be tested provided in an embodiment of this application is shown; Figure 3 Another cross-sectional view of the sample to be tested provided in an embodiment of this application is shown; Figure 4 A flowchart of the chip tilt angle measurement method provided in an embodiment of this application is shown; Figure 5 A schematic diagram of the structure of the weld column height measurement system provided in an embodiment of this application is shown; Figures 6A to 6C A detailed structural schematic diagram of the weld column height measurement system provided in an embodiment of this application is shown. Detailed Implementation

[0024] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0025] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0026] Secondly, this application provides a detailed description in conjunction with schematic diagrams. When detailing the embodiments of this application, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of this application. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0027] As described in the background section, the white light triangulation method measures the solder post height by analyzing the changes in the reflected light spot at the top of the bump during the movement of the sample under test, which consists of a chip and a substrate, through a measurement simulation model or actual measurement system. However, it is greatly affected by external factors such as ambient light, which can lead to deviations in the measurement results. Numerical simulation methods propose numerical prediction models to predict the final support height of the solder joint, but these often result in inaccurate predictions due to discrepancies between the assumptions and actual conditions. Therefore, providing an accurate method for measuring solder post height and chip tilt angle has become an urgent problem to be solved.

[0028] Based on the above technical problems, this application provides a method for measuring the height of a solder post, a method for measuring the tilt angle of a chip, and a system for measuring the height of a solder post. First, the total height of the chip and the solder post is obtained quickly and accurately through a height measuring device. Then, the thickness of the chip is determined based on interference information, and the height of the solder post can be calculated. The operation is simple and convenient, and the accuracy of measuring the height of the solder post is greatly improved.

[0029] For ease of understanding, the following detailed description, in conjunction with the accompanying drawings, provides a method for measuring solder pillar height, a method for measuring chip tilt angle, and a system for measuring solder pillar height according to embodiments of this application.

[0030] refer to Figure 1 , Figure 1 This is a flowchart illustrating a method for measuring the height of a weld column provided in an embodiment of this application. The method may include the following steps.

[0031] S101, acquire a pin distribution image of the sample to be tested. The sample to be tested includes a substrate, a chip, and multiple pins located between the substrate and the chip. The multiple pins include the target pin.

[0032] A device under test (DUT) is a sample for which the height of the solder pads needs to be measured. The DUT can include, from bottom to top, a substrate, solder pads, and a chip. Multiple solder pads are typically used to stably fix the substrate and chip in place. (Reference) Figure 2 , Figure 2 This is a cross-sectional view of the sample to be tested provided in an embodiment of this application. Multiple bonding pillars 102 are present between the substrate 101 and the chip 103. The shape of the bonding pillars 102 is not limited in this application and can be as follows: Figure 2 The diagram shows a two-layer structure, but it can also be a single-layer structure. The two-layer structure can be a lower layer connected to the substrate 101 and an upper layer connected to the chip 103. The single-layer structure can be a single-layer structure connected to both the substrate 101 and the chip 103.

[0033] To accurately measure the height of weld columns, it is first necessary to know their distribution within the sample to be tested; that is, to obtain a weld column distribution image. A weld column distribution image is an image showing the location and quantity distribution of the weld columns, from which the location and approximate size of each weld column can be determined. To facilitate the subsequent explanation of the weld column height measurement process, we will take a target weld column among multiple weld columns as an example to calculate its height. A target weld column refers to any one of the multiple weld columns.

[0034] In one possible implementation, S101, acquiring the weld column distribution image of the sample to be tested can specifically involve acquiring an image of the first surface of the sample to be tested located on the sample stage using an infrared camera to obtain an initial image; and extracting the area where the weld columns are located from the initial image based on a preset grayscale threshold to obtain the weld column distribution image.

[0035] The sample to be tested is placed on a sample stage with its first surface facing the infrared camera. The first surface refers to the surface of the chip in the sample that is furthest from the substrate, such as the top surface of the chip. Infrared light generated by an infrared light source is irradiated onto the first surface of the sample, and then the infrared camera captures an image of the first surface to obtain an initial image. Since the infrared camera (e.g., an infrared CCD camera) can receive infrared light, and infrared light can penetrate silicon chips but cannot penetrate tin solder pillars, the initial image acquired by the infrared camera can show the distribution of the solder pillars, but it is relatively blurry and requires further image processing.

[0036] As an example, during the acquisition of the initial image, a step scan is performed along the X / Y axes of the sample stage. The step size can be less than the field of view of the infrared camera lens, for example, 80% of the lens field of view, to avoid missed scans. Of course, the step size can also be equal to the lens field of view. Multiple sub-images are captured using the infrared camera. These multiple sub-images are then matched based on feature points to synthesize a panoramic initial image covering the entire weld column array area. The X-axis or Y-axis can be an axis within the plane of the sample stage. For example, the X-axis can be along one direction within the plane of the sample stage, and the Y-axis can be along another direction within the plane of the sample stage. The X-axis and Y-axis can be perpendicular to each other. The Z-axis can be a direction perpendicular to the XY plane of the sample stage.

[0037] To make the weld column distribution in the initial image clearer, the regions where the weld columns are located can be extracted based on a preset grayscale threshold. For example, bright spots (corresponding to weld column reflection signals) exceeding the preset grayscale threshold can be identified as weld column regions, while other regions can be identified as regions without weld columns, thus obtaining a clearer weld column distribution image. This preset grayscale threshold can be obtained by capturing grayscale images of the weld column locations on the sample and grayscale images of the locations without weld columns on the sample, and using the average grayscale value of the two images as the preset grayscale threshold. As an example, the preset grayscale threshold can be automatically adjusted based on the local grayscale distribution in the initial image to identify bright spot regions and obtain the weld column distribution image.

[0038] In summary, by first acquiring an initial image with a general distribution of solder pillars using an infrared camera, and then extracting the area where the solder pillars are located, a solder pillar distribution image with a precise distribution of solder pillars is obtained. This greatly improves the accuracy of the solder pillar distribution image, and the image acquisition is relatively simple, enabling accurate acquisition of the distribution of solder pillars located under the chip after chip packaging.

[0039] In one possible implementation, after obtaining the weld column distribution image, a circular fit can be performed on the area where the weld column is located in the weld column distribution image to determine the coordinates of the circle center relative to the sample stage, thereby obtaining the position of the weld column in the weld column distribution image.

[0040] To accurately represent the position of each weld post in the weld post distribution image, a circular fitting can be performed on the region where the weld post is located. The XY coordinates of the circle's center relative to the XY plane where the sample stage is located are used as the position of the circular weld post in the weld post distribution image. For example, the coordinates of weld post 1 are (X1, Y1), and the coordinates of weld post 2 are (X2, Y2), and so on. This achieves an accurate representation of the position of each weld post in the weld post array. Using the sample stage as the position reference makes the position of the weld posts more accurate, and the coordinates more uniform and concise.

[0041] S102, the height of the sample to be tested is measured by a height measuring device to obtain the distance between the first surface of the chip away from the substrate and the second surface of the substrate facing the chip.

[0042] Since the sample to be tested includes a chip and a substrate that have been fixed with solder pillars, and the lateral dimension of the substrate in the XY plane is usually larger than that of the chip in the XY plane, in order to determine the height of the solder pillars, the total height of the solder pillars and the chip, i.e., the distance between the first surface and the second surface, can be determined first.

[0043] The second surface refers to the surface of the substrate facing the chip, i.e., the surface on the substrate where the bonding pillars are located, such as the upper surface of the substrate. The height measuring device is a device used to measure the height of the surface. By using the height measuring device to measure the sample under test, the distance between the first and second surfaces can be obtained.

[0044] As an example, refer to Figure 2 As shown, the distance H2 between the upper surface of chip 103 and the upper surface of substrate 101 can be measured.

[0045] S103, based on the target position of the target weld pillar in the weld pillar distribution image, controls the infrared spectroscopy device to be positioned above the target weld pillar, so that the infrared light source in the infrared spectroscopy device emits a beam of light towards the chip, and the reflected light of the beam interferes on both sides of the chip to obtain an infrared spectral signal.

[0046] An infrared spectroscopy device may include an infrared light source for emitting infrared light, an infrared probe (i.e., an infrared objective lens), and a spectrometer for receiving reflected infrared signals. The infrared light may be infrared light in the wavelength range of 820 nanometers to 1550 nanometers. For example, see [reference needed]. Figures 6A-6B As shown, Figures 6A-6B This is a detailed schematic diagram of the weld column height measurement system provided in the embodiments of this application. Referring to 6A, in the infrared spectroscopy device 503, infrared light emitted by the infrared light source 5031 is incident on the surface of the sample to be tested through the second infrared objective lens 5034, and the reflected light from the surface to be tested returns to the second spectrometer 5036 through the infrared objective lens 5034.

[0047] Since infrared light continues to propagate downwards after passing through the upper chip 103, if there is no other structure (such as solder post 102) blocking the infrared light at this time, that is, in the area where there is no solder post 102, the infrared light will be incident on the surface of the lower substrate 101 and reflected. The reflected signal will interfere with the measurement of the solder post height and affect the measurement of the solder post height.

[0048] Therefore, in order to accurately measure the height of the solder pillars, it is necessary to prevent infrared light from incident on the substrate 101. That is, the incident position of the infrared light needs to be in the area where the solder pillars are located, and the solder pillars 102 are used to block the infrared light from continuing to propagate downward after penetrating the chip 103. This application first obtains an image of the solder pillar distribution to identify the area where the solder pillars are located. Then, it controls the infrared light emitted by the infrared spectroscopy device to be incident on the area where the solder pillars 102 are located to obtain the infrared spectral signals formed by the reflection of infrared light on the upper and lower surfaces of the chip 103.

[0049] In short, by placing the infrared spectroscopy device above the target weld column, infrared light is prevented from penetrating the weld column 102 and incident on the substrate 101, thereby avoiding interference from other signals on the infrared spectral signal and ensuring the accuracy of the weld column height measurement.

[0050] The target position refers to the location of the target solder post in the solder post distribution image, such as the XY coordinates of the target solder post relative to the XY plane of the sample stage. Since infrared light cannot penetrate the solder post, the beam emitted by the infrared light source 5031 towards the chip will penetrate the chip and be reflected on the top and bottom surfaces of the chip, such as... Figure 2 The middle arrow indicates light reflection. The reflected light from the upper surface of the chip and the reflected light from the lower surface of the chip interfere with each other, forming interference fringes. These fringes are then collected by the second spectrometer 5036, resulting in a single frame of infrared spectral signal. The infrared spectral signal carries information related to the interference fringes.

[0051] As an example, the infrared objective lens 5034 can be positioned at the location of the target solder post, such as at the coordinates (X1, Y1). The infrared light is reflected on the upper and lower surfaces of the chip, and the two reflected beams form interference fringes, which are received by the spectrometer.

[0052] S104 determines the chip thickness based on infrared spectral signals.

[0053] Next, since the interference information carried in the infrared spectral signal is formed by the interference of reflected light from the upper and lower surfaces of the chip, the infrared spectral signal will reflect the optical path difference between the two reflected beams. Therefore, the chip thickness H1 can be determined based on the infrared spectral signal.

[0054] In one possible implementation, S104, determining the chip thickness based on the infrared spectral signal can specifically involve converting the infrared spectral signal into a wavenumber-related reflectance spectral signal; performing a Fourier transform on the reflectance spectral signal to obtain a spectrum; performing peak-finding processing on the spectrum; and determining the chip thickness based on the thickness coordinates corresponding to the peaks.

[0055] In other words, specifically, the infrared spectral signal can first be converted into a reflectance spectral signal I(k) with respect to wavenumber k. This reflectance spectral signal includes multiple discrete function points for subsequent processing. Assuming the spectrum of the infrared source is S(k), the reflectance spectral signal I(k) of the M-layer structure can be obtained by superimposing the signals from each layer, and can be expressed as: .

[0056] in, Let m be the reflectivity of the m-th reflective layer. Let m be the distance of the m-th reflective layer relative to the zero position, and n be the refractive index of the reflective layer.

[0057] exist Figure 2 In this context, the zero-position refers to the location of the chip's upper surface. At the zero-position, the optical path difference between the reflected light (i.e., the reference light) from the chip's upper surface and the reflected light from the zero-position itself is zero. Figure 2In the structure shown, M can be considered to be 2, and the two reflective layers are the upper surface and the lower surface of the chip, respectively.

[0058] Next, a Fourier transform is performed on the reflection spectrum signal I(k) to obtain the spectrum F(z), where z is the distance between each reflection layer and the zero position relative to the zero position, such as z1, z2, etc. Since the zero position is the location of the first reflection layer, i.e. the upper surface of the chip, z1=0. z2 is the distance between the second reflection layer, i.e. the lower surface of the chip, and the zero position, i.e. the chip thickness H1.

[0059] Peak finding processing is performed on the spectrum F(z). Since only one interference occurred, there is only one peak in the spectrum. The horizontal coordinate of the peak in the spectrum, i.e., the thickness coordinate z2, is determined as the chip thickness H1. In summary, by first performing wavenumber conversion on the infrared spectral signal and then performing peak finding processing, the chip thickness is determined based on the coordinates of the peak, ensuring accurate measurement of the chip thickness without the need for complex operations.

[0060] S105, based on the spacing H2 and the chip thickness H1, determine the target bonding pillar height.

[0061] Since the spacing H2 is the sum of the chip thickness and the solder post height, the target solder post height can be obtained by subtracting the spacing H2 from the chip thickness H1, i.e., the target solder post height S = H2 - H1.

[0062] Among them, spacing and chip thickness refer to the spacing and thickness at the same or adjacent positions in the horizontal projection direction of the sample under test.

[0063] In summary, this application first uses a height measurement device to quickly and accurately obtain the total height of the chip and the solder pillars, then determines the chip thickness based on interference information, and finally calculates the height of the solder pillars. The operation is simple and convenient, and it greatly improves the accuracy of the solder pillar height. This application overcomes the limitation of white light interferometry in measuring the thickness of multi-layer structures separately, while retaining its high precision advantage, providing a better solution for measuring chip packaging-related parameters.

[0064] In one possible implementation, step S102, which involves measuring the height of the sample under test using a height measuring device to obtain the distance between the first surface of the chip facing away from the substrate and the second surface of the substrate facing the chip, may specifically include steps S1021-S1023.

[0065] S1021, based on the target position of the target weld column in the weld column distribution image, control the height measuring device to be positioned above the target weld column, and measure the height of the first surface through the height measuring device to obtain the first height between the first surface and the height measuring device.

[0066] The target position refers to the XY position of the target solder post in the solder post distribution image, such as the XY coordinates of the target solder post relative to the sample stage. Based on the target position, a height measuring device can be positioned above the target solder post. The height measuring device is used to measure the first surface of the chip, obtaining the distance between the first surface and the height measuring device (i.e., the height of the height measuring device), denoted as the first height Zs1. The position "above the target solder post" can be directly above the target solder post or diagonally above it, meaning it can be appropriately offset from directly above. For example, the height measuring device can be offset within a 15° range from directly above the target solder post.

[0067] S1022, the height measuring device is positioned above the exposed area of ​​the substrate not covered by the chip. The height measuring device measures the second surface of the exposed area to obtain the distance between the second surface and the height measuring device, that is, the second height Zs2 of the height measuring device relative to the second surface.

[0068] Since the substrate typically has a portion of bare area not covered by the chip, the height measuring device can be positioned above this bare area to measure the second surface of the substrate, obtaining the distance between the second surface and the height measuring device, denoted as the second height Zs2. The test position of the second height and the target position of the target bond post are located adjacent to each other in the horizontal projection direction of the sample under test; for example, the test position of the second height and the target position of the target bond post do not overlap in the horizontal projection on the substrate of the sample under test.

[0069] S1023, Based on the first height and the second height, determine the spacing between the first surface and the second surface.

[0070] By subtracting the first height and the second height, the distance between the first surface of the chip and the second surface of the substrate can be obtained, i.e., the distance H2 = This spacing is the sum of the chip thickness and the solder post height.

[0071] In summary, by first measuring the first height corresponding to the first surface of the chip and the second height corresponding to the second surface of the substrate, and then obtaining the spacing based on the two, the spacing can be calculated more easily and accurately, which also facilitates the subsequent calculation of the solder post height.

[0072] In one possible implementation, the height measuring device can be a white light interferometer or a white light confocal device.

[0073] A white light interferometer is a height measurement device based on the principle of white light interference; for example, it is a white light interferometer. A white light confocal device is a height measurement device based on the principle of white light confocalization; for example, it is a white light confocalist. Of course, other devices can also be used for height measurement, such as laser rangefinders. Using white light interferometers or white light confocal devices for height measurement provides greater accuracy and convenience.

[0074] In one possible implementation, when the height measuring device is a white light interferometer, S1021, the height of the first surface is measured by the height measuring device to obtain a first height between the first surface and the height measuring device. Specifically, incident light is emitted onto the first surface through a white light source in the white light interferometer, and the measured reflected light from the first surface interferes with the reference reflected light. The distance between the white light interferometer and the first surface is adjusted until the interference fringes meet the sharpness requirements, thus obtaining the first height Zs1. S1022, the height of the second surface of the exposed area is measured by the height measuring device to obtain a second height between the second surface and the height measuring device. Specifically, incident light is emitted onto the second surface through a white light source in the white light interferometer, and the measured reflected light from the second surface interferes with the reference reflected light. The distance between the white light interferometer and the second surface is adjusted until the interference fringes meet the sharpness requirements, thus obtaining the second height Zs2.

[0075] As an example, refer to Figures 6A-6B The white light interferometer in the device may include a white light source 5021, a second beam splitter 5023, an interferometer objective lens 5024, a second tube mirror 5025, and a first spectrometer 5026. Furthermore, during the measurement process, the white light interferometer 502 and the infrared spectrometer 503 can be switched for measurement. To ensure measurement accuracy, both the white light interferometer 502 and the infrared spectrometer 503 need to be positioned above the welding post. In one example of this application, for convenient switching, the white light interferometer 502 and the infrared spectrometer 503 can be positioned above the target welding post by moving the sample stage in steps along the X / Y axes. The X-axis or Y-axis can be an axis within the plane of the sample stage. Moving the sample on the sample stage ensures accurate white light interferometry and infrared interferometry measurements. The stepping movement of the sample stage can be achieved using a three-dimensional coordinate system. The sample stage is moved by motion sensors (such as accelerometers, gyroscopes, etc.) and a three-dimensional motor.

[0076] White light emitted from the white light source 5021 is directed by the second beam splitter 5023 onto the first surface of the chip in the test sample (DUT). The first surface reflects the light to obtain the measurement reflected light. Additionally, the white light, after passing through the beam splitter 5023, can also be incident on an interference objective lens, which includes a reference mirror. The reference mirror reflects the light to obtain reference reflected light. The measurement reflected light and the reference reflected light interfere to form interference fringes. By moving the sample stage and continuously adjusting the distance between the white light interference device and the first surface until the interference fringes are sufficiently clear, the first height Zs1 between the first surface of the chip and the height measurement device can be obtained.

[0077] As an example, by moving the sample stage, the field of view of the white light interferometer is moved to the marked target solder post position, for example, directly above (X1, Y1). The Z-axis height of the sample stage is adjusted to change the height of the sample under test, thereby adjusting the distance between the first surface of the chip and the interferometer objective lens until the interference fringes on the first surface of the chip are clear. The image and Z-axis coordinates are saved and recorded as the first height Zs1. In another example, the height of the interferometer objective lens can also be adjusted to adjust the distance between the first surface and the interferometer objective lens until the interference fringes are clear, thus determining the first height Zs1. Yet another example, the distance between the objective lens and the reference mirror in the reference optical path can also be adjusted until the interference fringes are clear to obtain the first height Zs1.

[0078] Similarly, when the white light interferometer is positioned above the exposed area of ​​the substrate, the measurement reflected light from the second surface of the substrate interferes with the reference reflected light from the reference mirror to form interference fringes. The distance between the white light interferometer and the second surface is continuously adjusted until the interference fringes are sufficiently clear. At this point, the second height Zs2 between the second surface and the height measuring device can be obtained.

[0079] As an example, the exposed area of ​​the packaging substrate at the edge of the chip (the substrate surface without chip coverage) is moved into the field of view of the white light interferometer. The height of the substrate is adjusted by adjusting the sample stage, and the image is saved and recorded as the second height Zs2. Alternatively, the height of the interferometer objective lens can be adjusted to regulate the distance between the second surface and the interferometer objective lens until the interference fringes are clear, thus determining the second height Zs2. Yet another example is that the distance between the beam splitter or measuring lens and the reference mirror in the reference optical path can be adjusted until the interference fringes are clear, thus obtaining the second height Zs2.

[0080] In summary, the first and second heights can be measured using a white light interferometer, which is simple to operate and has high measurement accuracy.

[0081] This application also provides a method for measuring chip tilt angle. (Reference) Figure 3 and Figure 4The method includes the following steps S401-S402.

[0082] S401: Determine the first weld column height of the first target weld column and the second weld column height of the second target weld column. The first target weld column and the second target weld column are arranged along the target direction. The first weld column height and the second weld column height can be measured according to the aforementioned weld column height measurement method.

[0083] S402: Based on the height of the first bonding post, the height of the second bonding post, and the length of the chip in the target direction, determine the tilt angle of the chip relative to the substrate in the target direction.

[0084] The first target bonding post or the second target bonding post can be the aforementioned target bonding post. The arrangement direction of the first target bonding post and the second target bonding post is denoted as the target direction. The first target bonding post can be considered to be located at one end of the chip, and the second target bonding post can be considered to be located at the other end of the chip.

[0085] As an example, refer to Figure 3 The image shows a cross-section of another sample to be tested according to an embodiment of this application. The leftmost solder post can be used as the first target solder post, and the rightmost solder post as the second target solder post. The direction from the first target solder post to the second target solder post can be any direction, such as the X or Y direction of the substrate. The first solder post height of the first target solder post is S1, the second solder post height of the second target solder post is S2, and the length of the chip in the target direction is W. Therefore, based on the first solder post height, the second solder post height, and the chip length, the tilt angle θ of the chip relative to the substrate in the target direction can be determined, which can be specifically expressed as: ; In summary, this application can not only measure the height of the solder pillars, but also obtain the tilt angle of the chip relative to the substrate based on the height of the solder pillars, thereby providing a more reliable test basis for chip packaging and realizing comprehensive testing of chip packaging effect.

[0086] Based on the aforementioned method for measuring weld column height, this application also provides a system for measuring weld column height, with reference to... Figure 5 and Figures 6A-6B The system includes an image acquisition device 501, a height measurement device 502, an infrared spectroscopy device 503, a first switching device 504, and a computing device 505.

[0087] Image acquisition device 501 is used to acquire images of the solder pillar distribution of a sample under test. The sample under test includes a substrate, a chip, and multiple solder pillars located between the substrate and the chip. The multiple solder pillars include target solder pillars.

[0088] As an example, see reference Figure 6A , Figure 6AThis is a detailed structural schematic diagram of the weld column height measurement system according to an embodiment of this application. The image acquisition device 501 may include a first infrared light source 5011 and an infrared camera 5012. The first infrared light source 5011 is configured to generate infrared light that illuminates a first surface of the sample to be tested. The wavelength of this infrared light may be in the range of 900 nanometers to 2500 nanometers.

[0089] Infrared camera 5012 is used to acquire images of the first surface of the sample under test located on the sample stage, obtaining an initial image. Based on a preset grayscale threshold, the region where the weld pillars are located is extracted from the initial image to obtain a weld pillar distribution image. As shown in the figure, infrared camera 5012 can be located above the first surface of the sample under test, that is, on the opposite side from the sample stage.

[0090] In some examples of this application, references Figure 6A The infrared camera 5012 may include a first modulation mirror assembly 50121, a first beam splitter 50122, a first infrared objective lens 50123, a first tube mirror 50124, and an infrared detector 50125. The first modulation mirror assembly 50121 receives illumination infrared light from a first infrared light source 5011 and focuses the light onto the first beam splitter 50122. The first beam splitter 50122 splits the infrared light into illumination light that illuminates the first infrared objective lens 50123, which then illuminates the first surface of the sample to be tested. The reflected light generated on the first surface is collected by the first infrared objective lens 50123 and propagates through the first beam splitter 50122 and the first tube mirror 50124 to the infrared detector 50125. The infrared detector 50125 analyzes the reflected light to obtain an initial image of the weld post. It should be understood that... Figure 6A The infrared camera 5012 shown is merely an example. Other structures can also be used for infrared cameras. For example, the infrared camera 5012 may not include the first modulation mirror assembly 50121 and the first beam splitter 50122, but only includes a first infrared objective lens 50123, a first tube mirror 50124, and an infrared detector 50125. The first infrared light source 5011 directly illuminates the first surface of the sample under test with infrared light through the modulation mirror, and the infrared light is reflected from the first surface of the sample. The first infrared objective lens 50123 is configured to collect the reflected light directly from the first surface of the sample, and the reflected light propagates to the first tube mirror 50124 and then to the infrared detector 50125. Specific structures can be derived from... Figure 6A This leads to the conclusion that, in this case, the infrared camera 5012 could be any other camera capable of capturing infrared images, such as an infrared CCD camera.

[0091] Optionally, after obtaining the weld column distribution image, the computing device 505 can obtain the weld column distribution image from the infrared detector 50125, perform circular fitting on the area where the weld column is located in the weld column distribution image, determine the coordinates of the center of the circle relative to the sample stage, and obtain the position of the weld column in the weld column distribution image.

[0092] refer to Figure 6A The height measuring device 502 is used to measure the height of the sample under test, obtaining the distance between the first surface of the chip facing away from the substrate and the second surface of the substrate facing the chip. In some examples, the height measuring device 502 can be a white light interferometer or a white light confocal device, for example... Figure 6A The white light interferometer and white light confocal device shown are height measuring devices based on the principle of white light confocalization, such as a white light confocalist. Of course, the height measuring device 502 can also be other devices, such as a laser rangefinder. Height measurement using a white light interferometer or a white light confocal device is more accurate and convenient. To save space, this article will not describe the white light focusing device and the laser rangefinder in detail. The principles of the white light focusing device and the laser rangefinder are understandable to those skilled in the art.

[0093] As an example, when the height measuring device 502 includes a white light interferometer, the white light interferometer 502 includes a white light source 5021, a second modulation mirror assembly 5022, a second beam splitter 5023, an interferometer objective lens 5024, a second tube mirror 5025, and a first spectrometer 5026.

[0094] Specifically, based on the target position of the target weld bead in the weld bead distribution image, the white light interferometer 502 is positioned directly above the target weld bead by moving the sample stage (i.e., the light emitted by the white light interferometer 502 illuminates the target weld bead). The white light source 5021 in the white light interferometer 502 emits white light. The wavelength range of the white light can be 380 nm to 780 nm. The second modulation mirror assembly 5022 can be a white light modulation mirror assembly. The white light is irradiated onto the first surface of the chip via the second modulation mirror assembly 5022, the second beam splitter 5023, and the interferometer objective 5024. Reflected light is generated on the first surface of the chip. This reflected light is collected by the interferometer objective 5024. The measured reflected light from the first surface interferes with the reference light generated by the interferometer objective 5024. After passing through the second beam splitter 5023, the interference light passes through the second tube mirror 5025 and reaches the first spectrometer 5026, forming a spectrum of interference fringes on the first spectrometer 5026. By moving the sample stage or the white light interferometer 502, the distance between the white light interferometer 502 and the first surface is adjusted until the interference fringes meet the clarity requirements. The interference fringes are then analyzed by the first spectrometer 5026, and the first height is obtained using the computing device 505.

[0095] The white light interferometer 502 is moved to the second surface of the exposed area by moving the sample stage or by moving the white light interferometer 502. The height of the second surface of the exposed area is measured to obtain the second height between the second surface and the white light interferometer 502. Specifically, incident light is emitted onto the second surface of the substrate by the white light source 5021 in the white light interferometer 502. The measured reflected light from the second surface interferes with the reference reflected light from the interferometer objective 5024. The distance between the white light interferometer 502 and the second surface is adjusted until the interference fringes meet the sharpness requirements. The interference fringes are analyzed by the first spectrometer 5026, and the second height is obtained using the calculation device 505. Based on the first height and the second height, the calculation device 502 determines the distance between the first surface and the second surface. By subtracting the first height and the second height, the distance between the first surface of the chip and the second surface of the substrate can be obtained, i.e., the distance H2 = This spacing is the sum of the chip thickness and the solder post height.

[0096] In this example of the application, the interference objective 5024 is a Mirau-type interferometer. The interference objective 5024 includes a white light objective 50241, an objective beam splitter 50242, and a reference mirror 50243. The white light objective 50241 propagates white light from the second beam splitter 5023 onto the objective beam splitter 50242. The objective beam splitter 50242 is a semi-transparent, semi-reflective film that splits the light into incident (transmitted) illumination light onto the first surface of the sample under test and reference light incident (reflected) onto the reference mirror 50243. The reference mirror 50243 reflects the reference light from the objective beam splitter 50242, and the reflected reference light illuminates the objective beam splitter 50242. Irradiating light incident on the first surface of the sample under test produces reflected light at the surface of the sample. This reflected light meets the reflected light of the reference light at the beam splitter 50242 of the objective lens, thus interfering and forming interference light. This interference light passes through the white light objective lens 50241, the second beam splitter 5023, and the second tube lens 5025 to reach the first spectrometer 5026. The first spectrometer 5026 analyzes the spectrum of the interference light.

[0097] As another example, the Milau-type interferometer objective 5024 included in the white light interferometer device 502 can be replaced with a Michelson-type interferometer objective, a Linnik-type interferometer objective, or other types of interferometer objectives. The structures of the Michelson-type and Linnik-type interferometer objectives can be designed by those skilled in the art as needed, and are not described in detail herein. Both the Michelson-type and Linnik-type interferometer objectives interfere with the reflected light generated from the first surface of the sample under test and the reflected light from the reference light to form interference light, which is acquired by the first spectrometer 5026.

[0098] The first switching device 504 is used to switch one of the image acquisition device 501, the height measurement device 502, and the infrared spectroscopy device 503 to perform the measurement.

[0099] In some embodiments, the first switching device 504 may include a driving device for driving the sample stage. When switching between the image acquisition device 501, the height measurement device 502, and the infrared spectroscopy device 503 for measurement, the sample stage can be driven to move, thereby moving the sample to be measured into the field of view of the image acquisition device 501, the height measurement device 502, or the infrared spectroscopy device 503. Optionally, the first switching device 504 may also include a stepper motor, a scale, and a motion axis, etc. The stepper motor, scale, and motion axis, etc., can be used to drive the sample stage and / or drive one or more of the image acquisition device 501, the height measurement device 502, or the infrared spectroscopy device to move along the X-axis and / or Y-axis and / or Z-axis. The associated stepper motor and scale, etc., are foreseeable to those skilled in the art. They are not described in detail herein.

[0100] Infrared spectroscopy device 503 is used to emit a light beam onto the chip via an infrared light source within the infrared spectroscopy device 503. The reflected light from the light beam interferes with the light reflected from both sides of the chip, thus obtaining an infrared spectral signal. Infrared spectroscopy device 503 can be... Figures 6A-6B The infrared spectroscopy device 503 shown is shown.

[0101] refer to Figure 6A The infrared spectrometer 503 includes a second infrared light source 5031, a third modulation mirror assembly 5032, a third beam splitter 5033, a second infrared objective lens 5034, a third tube mirror 5035, and a second spectrometer 5036. The infrared spectrometer 503 emits a light beam towards the chip through the second infrared light source 5031. The reflected light from the two surfaces of the chip interferes to obtain an infrared spectral signal. The third modulation mirror assembly 5032 can be an infrared modulation mirror assembly.

[0102] During the measurement process, based on the weld pillar distribution image obtained by the image acquisition device 501, the sample stage or the infrared spectrometer 503 can be moved via the first switching device 504, controlling the infrared spectrometer 503 to be positioned above the target weld pillar. The second infrared light source 5031 in the infrared spectrometer 503 emits a beam of light towards the chip. The beam emitted by the second infrared light source 5031 is modulated by the third modulation mirror assembly 5032, generating a beam that illuminates the third beam splitter 5033. The third beam splitter 5033 splits the beam emitted by the second infrared light source 5031 into beams that are emitted towards the second infrared objective lens 5034. The second infrared objective lens 5034 illuminates the first surface of the sample under test. This beam is reflected from the upper and lower surfaces of the chip under test, respectively. The reflected light superimposes to form interference light, which is collected by the second infrared objective lens 5034. The third beam splitter 5033 propagates the interference light to the third tube mirror 5035, and after passing through the third tube mirror 5035, it reaches the second spectrometer 5036. The second spectrometer 5036 obtains a single-frame infrared spectral signal. This infrared spectral signal carries interference information from the reflected light from the upper and lower surfaces of the chip, reflecting the optical path difference between these two reflected beams. The second spectrometer 5036 can be an infrared spectrometer.

[0103] The computing device 505 obtains an infrared spectral signal from the second spectrometer 5036 and can determine the chip thickness based on the spectral signal from the second spectrometer 5036. Specifically, the computing device 505 converts the infrared spectral signal into a reflectance spectral signal with respect to wavenumber. The computing device 505 performs a Fourier transform on the reflectance spectral signal to obtain a spectrum; it performs peak-finding processing on the spectrum and determines the chip thickness based on the thickness coordinates corresponding to the peaks. The computing device 505 is further configured to determine the target bonding pillar height based on the spacing and the chip thickness.

[0104] In some embodiments, reference Figure 6BThe first infrared light source 5011 and the second infrared light source 5031 can use the same light source; the first modulation mirror assembly 50212 and the third modulation mirror assembly 5032 can use the same mirror group; the first beam splitter 50122 and the third beam splitter 5033 can use the same beam splitter; the first tube mirror 50124 and the third tube mirror 5035 can use the same tube mirror; the first infrared objective lens 50123 and the second infrared objective lens 5034 can be the same objective lens. In this case, the weld column height measurement system can further include a fourth beam splitter 50126. In this embodiment, the weld column height measurement system also includes a fourth infrared beam splitter 50126. The fourth beam splitter 50126 is located within the optical path of the infrared detector 50125 and also within the optical path of the second spectrometer 5036. When the image acquisition device 501 acquires an infrared image of the first surface of the chip, the fourth beam splitter 50126 guides the reflected light from the first surface of the chip into the field of view of the infrared detector 50125, thereby acquiring an infrared image of the first surface of the chip. When the infrared spectroscopy device 503 obtains the reflection interference spectrum of the first and second surfaces of the chip, the fourth beam splitter 50126 guides the reflected light from the first surface of the chip into the second spectrometer 5036, thereby obtaining a single-frame infrared spectral signal. The infrared spectral signal carries interference information of the reflected light from the upper surface and the lower surface of the chip.

[0105] In some embodiments, the fourth beam splitter 50126 can be replaced by a movable first reflector. When the image acquisition device 501 acquires an infrared image of the first surface of the chip, the second switching device can be used to move the first reflector into the optical path of the second spectrometer 5036. The reflective surface of the first reflector faces the infrared detector 50125, and the backlight surface of the first reflector faces the infrared spectrometer 5036. The first reflector blocks the reflected light from the first surface of the chip from reaching the infrared spectrometer 5036 and guides the reflected light from the first surface of the chip into the field of view of the infrared detector 50125, thereby acquiring an infrared image of the first surface of the chip. When the infrared spectroscopy device 503 obtains the reflection interference spectrum of the first and second surfaces of the chip, the second switching device can be used to move the first reflector out of the optical path of the second spectrometer 5036, so that the reflected light from the upper and lower surfaces of the chip illuminates the infrared spectrometer 5036. In other embodiments, the positions of the infrared detector 50125 and the second spectrometer 5036 are different. Figure 6BThe positions of the two components are interchanged. The first reflector is configured such that when the image acquisition device 501 acquires an infrared image of the first surface of the chip, the first reflector is moved out of the optical path of the infrared detector 50125; when the infrared spectroscopy device 503 acquires interference light, the first reflector is moved into the optical path of the second spectrometer 5036, thereby acquiring the interference light. The second switching device may include a stepper motor, a scale, and a motion axis, etc. The stepper motor, scale, and motion axis, etc., can be used for the first reflector.

[0106] In some embodiments, reference Figure 6C The height measuring device 502 and the image acquisition device 501 can share some optical components. Figure 6C In this embodiment, the white light source 5021 of the height measuring device 502 can be a xenon lamp. The xenon lamp emits light with a color temperature range of 3000K to 12000K (Kelvin). An infrared filter 50111 filters the light emitted by the xenon lamp 5021, thus the combination of the infrared filter 50111 and the xenon lamp 5021 constitutes the first infrared light source 5011 of the image acquisition device 501. The first infrared modulation mirror assembly 50121 and the second modulation mirror assembly 5022 can be the same modulation mirror assembly. The first beam splitter 50122 and the second beam splitter 5023 can be the same beam splitter, and the first tube mirror 50124 and the second tube mirror 5025 can be the same tube mirror. In this embodiment, the first infrared objective lens 50123 of the image acquisition device 501 and the interference objective lens 5024 of the height measuring device 502 are not the same assembly.

[0107] The weld column height measurement system further includes a third switching device. This third switching device is configured to, when using the image acquisition device 501 to capture an infrared image of the first surface of the sample under test, move the infrared filter 50111 into the output optical path of the xenon lamp 5021, so that the first modulation mirror assembly 50121 obtains infrared light from the infrared filter 50111. The third switching device is further configured to switch the first infrared objective lens 50123 to the range of the beam splitter of the first beam splitter 50122. When using the height measurement device 502 to measure the height, the infrared filter 50111 is moved out of the output optical path of the xenon lamp 5021, so that the second modulation mirror assembly 5022 obtains white light from the xenon lamp 5021, and the interference objective lens 504 is switched to the range of the beam splitter of the second beam splitter 5023. The third switching device can use a linear motion axis or a rotation axis for switching. The fourth switching device 509 can use a linear motion axis or a rotation axis to switch between the first infrared objective lens 50123 and the interference objective lens 5024. The fourth switching device 509 may include a linear axis or a rotational axis. When the fourth switching device 509 includes a linear axis, the first infrared objective lens 50123 of the image acquisition device 501 and the interferometer objective lens 5024 of the height measurement device 502 are both disposed on the linear axis, and the first infrared objective lens 50123 of the image acquisition device 501 and the interferometer objective lens 5024 of the height measurement device 502 move linearly along the linear axis, thereby achieving switching. When the fourth switching device 509 includes a rotational axis, the first infrared objective lens 50123 of the image acquisition device 501 and the interferometer objective lens 5024 of the height measurement device 502 rotate around the rotational axis, thereby achieving switching. In this embodiment, the weld post height measurement system also includes a fifth beam splitter 508. When the image acquisition device 501 acquires an infrared image of the first surface of the chip, the fifth beam splitter 508 guides the reflected light from the first surface of the chip into the field of view of the infrared detector 50125, thereby acquiring an infrared image of the first surface of the chip. When the height measuring device 502 is used for measurement, the fifth beam splitter 508 guides the interference light into the first spectrometer 5026.

[0108] In some embodiments, to prevent infrared reflected light from interfering with the first spectrometer 5026 or white light interference light from interfering with the infrared detector 50125 when measuring using the image acquisition device 501 or the height measurement device 502, the fifth infrared beam splitter 508 in the weld column height measurement system can be replaced with a second reflector 508. The second reflector 508, driven by the second switching device, can move into the field of view of the first tube mirror 50124 when the image acquisition device 501 captures an infrared image. The reflective surface of the second reflector 508 faces the infrared detector 50125, and the backlight surface faces the first spectrometer 5026, thereby reflecting the infrared light from the first tube mirror 50124 to the infrared detector 50125. The second reflector 508 is further configured to move out of the field of view of the second tube mirror 5025 when the height is measured using the height measurement device 502, driven by the second switching device 509, so that the interference light from the second tube mirror 5025 enters the first spectrometer 5026. In other embodiments, the positions of the first spectrometer 5026 and the infrared detector 50125 may be relative to each other. Figure 6C The positions of the two mirrors are interchanged. In this case, when the image acquisition device 501 captures an infrared image, the second reflector 508 can be moved out of the field of view of the first tube mirror 50124, so that the infrared light from the first tube mirror 50124 directly illuminates the infrared detector 50125; when the height measurement device 502 measures the height, the second reflector 508 moves into the field of view of the second tube mirror 5025, with the reflective surface facing the first spectrometer 5026 and the backlight surface facing the infrared detector 50125, so that the interference light from the second tube mirror 5025 is reflected to the first spectrometer 5026.

[0109] The third and fourth switching devices may include stepper motors, scales, and motion axes. The stepper motors, scales, and motion axes can be used to drive the first infrared objective 50123, the interference objective 5024 infrared filter, and the second reflecting mirror 508.

[0110] The computing device 505 is also used to measure the chip tilt angle. Specifically, the computing device 505 is configured to: determine a first post height of a first target post and a second post height of a second target post, the first target post and the second target post being arranged along a target direction; and determine the tilt angle of the chip relative to the substrate in the target direction based on the first post height, the second post height, and the length of the chip in the target direction.

[0111] The computing device disclosed herein may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a complex programmable logic device (CPLD), and the processor may also adopt a multi-core architecture.

[0112] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by program instructions in hardware. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium can be at least one of the following media: read-only memory (ROM), RAM, magnetic disk, or optical disk, etc., and other media capable of storing program code.

[0113] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0114] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, the apparatus embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0115] The above description is merely a preferred embodiment of this application. Although this application has disclosed preferred embodiments above, it is not intended to limit this application. Any person skilled in the art can make many possible variations and modifications to the technical solutions of this application using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the technical solutions of this application. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application shall still fall within the protection scope of the technical solutions of this application.

Claims

1. A stud height measurement method, characterized by, include: Acquire a pin distribution image of the sample to be tested, wherein the sample to be tested includes a substrate, a chip, and multiple pins located between the substrate and the chip, and the multiple pins include target pins; The height of the sample under test is measured by a height measuring device to obtain the distance between the first surface of the chip facing away from the substrate and the second surface of the substrate facing the chip. Based on the target position of the target weld post in the weld post distribution image, the infrared spectroscopy device is controlled to be positioned above the target weld post, so that the infrared light source in the infrared spectroscopy device emits a light beam toward the chip, and the reflected light of the light beam on both sides of the chip interferes to obtain an infrared spectral signal. The chip thickness is determined based on the infrared spectral signal; The target bonding pillar height is determined based on the spacing and the chip thickness.

2. The method of claim 1, wherein, Determining the chip thickness based on the infrared spectral signal includes: The infrared spectral signal is converted into a reflectance spectral signal with respect to wavenumber; Perform a Fourier transform on the reflected spectrum signal to obtain the spectrum; The spectrum is processed to find peaks, and the chip thickness is determined based on the thickness coordinates corresponding to the peaks.

3. The method according to claim 1 or 2, characterized in that, The step of measuring the height of the sample under test using a height measuring device to obtain the distance between the first surface of the chip facing away from the substrate and the second surface of the substrate facing the chip includes: Based on the target position of the target weld column in the weld column distribution image, the height measuring device is controlled to be positioned above the target weld column, and the height of the first surface is measured by the height measuring device to obtain the first height between the first surface and the height measuring device. The height measuring device is positioned in an exposed area of ​​the substrate not covered by the chip. The height of the second surface of the exposed area is measured by the height measuring device to obtain a second height between the second surface and the height measuring device. The distance between the first surface and the second surface is determined based on the first height and the second height.

4. The method according to claim 3, characterized in that, The height measuring device is a white light interferometer or a white light confocal device.

5. The method according to claim 4, characterized in that, When the height measuring device is a white light interferometer, the step of measuring the height of the first surface using the height measuring device to obtain the first height between the first surface and the height measuring device includes: Incident light is emitted onto the first surface through a white light source in the white light interferometer. The measured reflected light from the first surface interferes with the reference reflected light. The distance between the white light interferometer and the first surface is adjusted until the interference fringes meet the sharpness requirements, and the first height is obtained. The step of measuring the height of the second surface of the exposed area using the height measuring device to obtain a second height between the second surface and the height measuring device includes: Incident light is emitted onto the second surface through a white light source in the white light interferometer. The measured reflected light from the second surface interferes with the reference reflected light. The distance between the white light interferometer and the second surface is adjusted until the interference fringes meet the sharpness requirements, thus obtaining the second height.

6. The method according to claim 1, characterized in that, The acquisition of the weld column distribution image of the sample to be tested includes: An initial image is obtained by acquiring an image of the first surface of the sample to be tested located on the sample stage using an infrared camera; Based on a preset grayscale threshold, the region where the weld column is located is extracted from the initial image to obtain the weld column distribution image.

7. The method according to claim 6, characterized in that, The method further includes: A circular fit is performed on the area where the weld column is located in the weld column distribution image to determine the coordinates of the center of the circle relative to the sample stage, thereby obtaining the position of the weld column in the weld column distribution image.

8. A method for measuring chip tilt angle, characterized in that, The method includes: The first weld column height of the first target weld column and the second weld column height of the second target weld column are determined. The first target weld column and the second target weld column are arranged along the target direction. The first weld column height and the second weld column height are obtained by the weld column height measurement method according to any one of claims 1-7. Based on the height of the first solder post, the height of the second solder post, and the length of the chip in the target direction, the tilt angle of the chip relative to the substrate in the target direction is determined.

9. A system for measuring the height of a weld column, characterized in that, The system includes: An image acquisition device is used to acquire a pin distribution image of a sample to be tested, the sample to be tested including a substrate, a chip, and multiple pins located between the substrate and the chip, the multiple pins including a target pin; A height measuring device is used to measure the height of the sample to be tested, and to obtain the distance between the first surface of the chip facing away from the substrate and the second surface of the substrate facing the chip. An infrared spectroscopy device is used to emit a light beam toward the chip through an infrared light source in the infrared spectroscopy device. The reflected light from the light beam on both sides of the chip interferes to obtain an infrared spectral signal. The first switching device is used to switch one of the image acquisition device, the height measurement device, and the infrared spectroscopy device to perform the measurement. A computing device is configured to determine the chip thickness of the chip based on the infrared spectral signal, and to determine the target bonding height of the target bonding post based on the spacing and the chip thickness.

10. The system according to claim 9, characterized in that, The height measuring device is a white light interferometer or a white light confocal device.

Images