Chip pin solder ball height information measuring method and related equipment

Abstract

The invention provides a chip pin solder ball height information measurement method and related equipment, and relates to the technical field of packaged chip pin height measurement, and the method comprises the steps: projecting a preset stripe to a packaged chip from a plurality of preset angles, and obtaining a plurality of stripe phase shift images; determining a first wrapping phase of a preset stripe on a chip pin solder ball according to the stripe phase shift image; recovering the first wrapped phase into a continuous first absolute phase diagram by using a branch cutting method; for each pixel coordinate point in the first absolute phase diagram, performing fitting calibration on the absolute phase of the pixel coordinate point by using a calibration block, and determining initial relative height information of a chip pin solder ball; and superposing the initial relative height information at different preset angles to obtain unshielded relative height information of the chip pin solder balls. The problems that in the prior art, the efficiency of manual one-by-one measurement is very low, the situation of missing measurement is likely to occur, and the inspection quality cannot be ensured are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of measuring the pin height of encapsulated chips, and particularly relates to a method for measuring the height information of chip pin solder balls and related equipment. Background Art

[0002] BGA (Ball Grid Array) packaging is a packaging method in which a certain surface is completely covered or partially covered with pins in a grid arrangement. BGA type chips achieve interconnection with a printed circuit board (PCB) by making an array on the substrate at the bottom of the chip and using spherical solder joints as the I / O ends of the circuit. With the increasing integration of PCBs, certain requirements are imposed on the design of chips. The pins of chips are mainly used for data transmission. The more pins there are, the larger the amount of data exchanged by the chip with the outside. This BGA packaging type has a relatively large upper limit on the coverage area of external input / output interfaces, and more pins can be designed and installed to increase the data throughput of the chip. Currently, the BGA type packaging has become a mainstream electronic packaging technology that has developed very rapidly in recent years.

[0003] BGA packaging type chips are mainly fixed to the circuit board by soldering, and contact the PCB through the chip pins to achieve chip power supply and data interaction with the PCB. The height and coplanarity of the solder balls affect the quality of the contact between the chip and the circuit board. Therefore, after the chip manufacturing is completed, it is necessary to inspect the height of the pin solder balls. Currently, it mainly relies on manual measurement of each chip pin with the help of tools. Due to the large number of chip pins, the efficiency of manual measurement one by one is very low, and it is easy to miss measurements, unable to ensure the inspection quality. Summary of the Invention

[0004] Aiming at the deficiencies in the prior art, the present invention provides a method for measuring the height information of chip pin solder balls and related equipment, which solves the problems in the prior art that the efficiency of manual measurement one by one is very low, and it is easy to miss measurements, unable to ensure the inspection quality.

[0005] At least one embodiment of the present invention provides a method for measuring the height information of chip pin solder balls, including:

[0006] Obtaining a fringe phase-shifted image, where the fringe phase-shifted image is an image obtained by projecting a preset fringe from multiple preset angles onto an encapsulated chip and then photographing the chip;

[0007] For each of the fringe phase-shifted images, determining a first wrapped phase of the preset fringe on the chip pin solder balls according to the fringe phase-shifted image;

[0008] Using the branch-cut method to restore the first wrapped phase into a continuous first absolute phase map;

[0009] For each pixel coordinate point in the first absolute phase diagram, use a calibration block to fit and calibrate the absolute phase of the pixel coordinate point to determine the initial relative height information of the chip pin solder balls;

[0010] Superimpose the initial relative height information at different preset angles to obtain the unobstructed relative height information of the chip pin solder balls.

[0011] The technical solution provided by the present invention at least has the following beneficial effects:

[0012] The present invention projects stripes covering the entire chip, collects the stripe phase-shifted images, sequentially collects the phase-shifted stripe images, and unpacks them to obtain the first wrapped phase and the first absolute phase diagram. Subsequently, use a calibration block to calibrate each pixel point in the first absolute phase diagram, and all the height information of the pin solder balls can be calculated in one go. Through multiple measurement operations, superimpose the initial relative height information at different preset angles, which can eliminate the void invalid areas, improve the measurement and inspection accuracy, and save the time for chip measurement and statistics.

[0013] In a method for measuring the height information of chip pin solder balls provided in one embodiment of the present invention, for each pixel coordinate point in the first absolute phase diagram, using a calibration block to fit and calibrate the absolute phase of the pixel coordinate point to determine the initial relative height information of the chip pin solder balls includes:

[0014] Obtain a calibration stripe phase-shifted image, where the calibration stripe phase-shifted image is an image obtained by projecting a preset stripe onto a calibration block from multiple preset angles and then photographing the chip;

[0015] For each calibration stripe phase-shifted image, determine the second wrapped phase of the preset stripe on the calibration block according to the calibration stripe phase-shifted image;

[0016] Use the branch cut method to restore the second wrapped phase into a continuous second absolute phase diagram;

[0017] For each pixel coordinate point in the second absolute phase diagram, use the true height value of the calibration block to fit and calibrate the absolute phase of the pixel coordinate point to determine the calibration parameter distribution information at each preset angle;

[0018] For each pixel coordinate point in the first absolute phase diagram, use the calibration parameter distribution information at the same preset angle to fit and calibrate the absolute phase of the pixel coordinate point to determine the initial relative height information of the chip pin solder balls.

[0019] The technical solution provided by the present invention at least has the following beneficial effects:

[0020] By measuring the calibration block with known height information through the above steps, each pixel coordinate point in the second absolute phase map can be fitted and calibrated with the known true height information, and the first absolute phase map can be fitted and calibrated using the obtained calibrated parameter distribution information, thereby determining the initial relative height information of the chip pin solder balls.

[0021] In a method for measuring the height information of chip pin solder balls provided in one embodiment of the present invention, the step of generating the preset stripes includes:

[0022] According to the true physical size corresponding to a single resolution unit of the projector and in combination with the theoretical height of the chip pin solder balls, determine the minimum number of stripe periods;

[0023] In combination with the minimum number of stripe periods, generate four-step phase-shifted cosine stripes as the preset stripes.

[0024] The technical solution provided by the present invention at least has the following beneficial effects:

[0025] Using the generated four-step phase-shifted cosine stripes for projection can ensure that one stripe can be equally phase-shifted four times on the solder ball and cannot exceed the diameter range of the solder ball, improving the accuracy of the final measurement and inspection.

[0026] In a method for measuring the height information of chip pin solder balls provided in one embodiment of the present invention, it further includes:

[0027] Obtain a chip pin solder ball height comparison image without stripes;

[0028] According to the chip pin solder ball height comparison image, determine the 2D mask of the solder balls in the preset area on the image;

[0029] In combination with the unobstructed relative height information of the chip pin solder balls and the 2D mask, determine the relative height information of the solder balls in the preset area.

[0030] The technical solution provided by the present invention at least has the following beneficial effects:

[0031] Using the 2D mask can reduce the calculation of the height information of unnecessary areas on the chip surface, reduce the calculation amount, and improve the measurement efficiency.

[0032] In a method for measuring the height information of chip pin solder balls provided in one embodiment of the present invention, according to the chip pin solder ball height comparison image, determining the 2D mask of the solder balls in the preset area on the image includes:

[0033] According to the chip pin solder ball height comparison image, perform preprocessing through mean filtering to obtain a processed intermediate image;

[0034] Extract solder balls in a preset area of the intermediate image using a threshold method to generate a 2D mask.

[0035] In a method for measuring the height information of chip pin solder balls provided in one embodiment of the present invention, it further includes:

[0036] According to the height information of the solder balls in the preset area, determine the coplanarity parameter of the chip pins by fitting a plane.

[0037] The technical solution provided by the present invention at least has the following beneficial effects:

[0038] By calculating the coplanarity parameter of the chip pins based on the obtained height information of the solder balls in the preset area, the quality of the contact between the chip and the circuit board can be clearly judged.

[0039] At least one embodiment of the present invention also provides a system for measuring the height information of chip pin solder balls, including:

[0040] A data acquisition module, including an image acquisition unit and a projection control unit, where the projection control unit is used to project preset stripes from multiple preset angles onto the packaged chip, and the image acquisition unit is used to obtain multiple fringe phase-shifted images;

[0041] A calibration measurement module, including an unpacking unit, a calibration unit, and a measurement unit. Among them, the unpacking unit is used for each of the fringe phase-shifted images to determine the first wrapped phase of the preset stripes on the chip pin solder balls according to the fringe phase-shifted image; use the branch cut method to restore the first wrapped phase into a continuous first absolute phase map;

[0042] The calibration unit is used for each pixel coordinate point in the first absolute phase map to fit and calibrate the absolute phase of the pixel coordinate point using a calibration block to determine the initial relative height information of the chip pin solder balls;

[0043] The measurement unit is used to superimpose the initial relative height information at different preset angles to obtain the unobstructed relative height information of the chip pin solder balls.

[0044] In a system for measuring the height information of chip pin solder balls provided in one embodiment of the present invention, it includes:

[0045] The projection control unit is further used to project preset stripes from multiple preset angles onto the calibration block, and the image acquisition unit is further used to obtain multiple calibration fringe phase-shifted images;

[0046] The unpacking unit is further configured to, for each of the calibrated fringe phase-shifted images, determine the second wrapped phase of the preset fringe on the calibration block according to the calibrated fringe phase-shifted image; and use the branch cut method to restore the second wrapped phase into a continuous second absolute phase map.

[0047] The calibration unit is configured to, for each pixel coordinate point in the second absolute phase map, use the true height value of the calibration block to perform fitting calibration on the absolute phase of the pixel coordinate point to determine the distribution information of the calibration parameters at each preset angle; and for each pixel coordinate point in the first absolute phase map, use the distribution information of the calibration parameters at the same preset angle to perform fitting calibration on the absolute phase of the pixel coordinate point to determine the initial relative height information of the chip pin solder balls.

[0048] The present invention also provides a computer-readable storage medium, in which instructions are stored. When the instructions are run on a terminal device, the terminal device is caused to execute a method for measuring the height information of chip pin solder balls as described above.

[0049] The present invention also provides an electronic device, including a memory, a processor, and a program stored on the memory and running on the processor. When the processor executes the program, a method for measuring the height information of chip pin solder balls as described above is implemented. Description of the Drawings

[0050] Figure 1 is a schematic flowchart of a method for measuring the height information of chip pin solder balls;

[0051] Figure 2 is a logical relationship diagram of a system for measuring the height information of chip pin solder balls;

[0052] Figure 3 is a layout relationship diagram of an image acquisition unit, a projection control unit, and a chip;

[0053] Figure 4 is a three-dimensional view of a calibration block;

[0054] Figure 5 is a schematic structural diagram of the electronic device provided by the present invention.

[0055] In the drawings, the list of components represented by each reference numeral is as follows:

[0056] 10. Electronic device, 11. Processor, 12. Read-only memory (ROM), 13. Random access memory (RAM), 14. Bus, 15. Input / output (I / O) interface, 16. Input unit, 17. Output unit, 18. Storage unit, 19. Communication unit. Detailed Embodiments

[0057] The principles and features of the present invention will be described below. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0058] The present invention provides a method for measuring the height information of chip pin solder balls, with reference here Figure 1 as shown, including:

[0059] Obtain a fringe phase-shifted image, where the fringe phase-shifted image is an image obtained by projecting a preset fringe from multiple preset angles onto a packaged chip and then photographing the chip;

[0060] For each of the fringe phase-shifted images, determine the first wrapped phase of the preset fringe on the chip pin solder balls according to the fringe phase-shifted image;

[0061] Use the branch cut method to restore the first wrapped phase into a continuous first absolute phase map;

[0062] For each pixel coordinate point in the first absolute phase map, use a calibration block to fit and calibrate the absolute phase of the pixel coordinate point to determine the initial relative height information of the chip pin solder balls;

[0063] Superimpose the initial relative height information at different preset angles to obtain the unobstructed relative height information of the chip pin solder balls.

[0064] The present invention projects fringes covering the entire chip, collects fringe phase-shifted images, sequentially collects phase-shifted fringe images, unpacks them to obtain the first wrapped phase and the first absolute phase map, and then uses a calibration block to calibrate each pixel point in the first absolute phase map, so that the height information of all pin solder balls can be calculated at one time. Through multiple measurement operations, the initial relative height information at different preset angles is superimposed, which can eliminate and reduce the void invalid areas, improve the measurement and inspection accuracy, and save the time for chip measurement and statistics.

[0065] In a more specific embodiment provided by the present invention, the method for measuring the height information of chip pin solder balls includes:

[0066] S1. Project a preset fringe from multiple preset angles onto a packaged chip to obtain multiple fringe phase-shifted images. In this embodiment, the multiple preset angles are 2, which are distributed on the left and right sides of the packaged chip;

[0067] Specifically, the generation steps of the preset fringe include:

[0068] Determine the minimum number of fringe periods according to the true physical size corresponding to a single resolution unit of the DLP projector and the theoretical height of the chip pin solder balls;

[0069] Combined with the minimum number of fringe periods, a four-step phase-shifted cosine fringe is generated using a fringe generation tool as the preset fringe.

[0070] The relationship of the four-step phase-shifted cosine fringe is shown in Formula 1; it is written into the DLP projector system through a DLP projector burning tool, and the projection timing and projection trigger mechanism are set;

[0071] I1(x,y) = a(x,y) + b(x,y)cos(φ)

[0072] I2(x,y) = a(x,y) + b(x,y)cos(φ - π / 2)

[0073] I3(x,y) = a(x,y) + b(x,y)cos(φ - π)

[0074] I4(x,y) = a(x,y) + b(x,y)cos(φ - 3π / 2)

[0075] Where a is the background gray level, b is the modulation gray level, and I is the fringe image.

[0076] Subsequently, a CCD camera is used for shooting to obtain multiple fringe phase-shifted images.

[0077] S2. For each of the fringe phase-shifted images, determine the first wrapped phase of the four-step phase-shifted cosine fringe on the chip pin solder ball according to the fringe phase-shifted image and the following formula;

[0078]

[0079] S3. Use the branch cut method to restore the first wrapped phase into a continuous first absolute phase map;

[0080] For each pixel coordinate point in the first absolute phase map, use a calibration block to fit and calibrate the absolute phase of the pixel coordinate point to determine the initial relative height information of the chip pin solder ball;

[0081] Specifically, the structure of the calibration block refers to Figure 4 as shown. The height of the calibration block should be higher than the measurement height range, and the calibration model is a parallel axis model;

[0082] Project the four-step phase-shifted cosine fringe onto the calibration block from left and right angles to obtain at least two calibration fringe phase-shifted images;

[0083] For each of the calibration fringe phase-shifted images, determine the second wrapped phase of the preset fringe on the calibration block according to the calibration fringe phase-shifted image;

[0084] Use the branch cut method to restore the second wrapped phase into a continuous second absolute phase map;

[0085] For each pixel coordinate point in the second absolute phase diagram, use the true height value of the calibration block to perform fitting calibration on the absolute phase of the pixel coordinate point, and determine the distribution information of the calibration parameters at each preset angle;

[0086] For each pixel coordinate point in the first absolute phase diagram, use the distribution information of the calibration parameters at the same preset angle to perform fitting calibration on the absolute phase of the pixel coordinate point, and determine the initial relative height information of the chip pin solder balls.

[0087] S4. Superimpose the initial relative height information from the left and right angles to obtain the unobstructed relative height information of the chip pin solder balls, so as to eliminate the occlusion area.

[0088] S5. Set the CCD camera to the exposure state, and collect a height comparison image of the chip pin solder balls without stripes. In this way, a high-contrast image of the chip solder balls can be obtained without relying on external lighting; control the DLP to start and stop projection through the I2C communication method. A trigger signal can be synchronously output during each projection to trigger the camera acquisition module to acquire the corresponding timing projection image. After the projection is completed, the host computer module packs the image data in sequence and transfers it to the calibration measurement module for measurement of the chip pins;

[0089] S6. According to the height comparison image of the chip pin solder balls, perform preprocessing through mean filtering to obtain the processed intermediate image;

[0090] Use the threshold method to extract the solder balls in the preset area of the intermediate image to generate a 2D mask, and then only focus on the height data corresponding to the 2D mask area

[0091] Combine the unobstructed relative height information of the chip pin solder balls and the 2D mask to determine the relative height information of the solder balls in the preset area. In this embodiment, the height information only needs to include the average relative height and the extreme height of the local solder balls.

[0092] When calculating the average height of the local solder balls, calculate the average height within the effective height range in the set average area according to the extracted solder ball coordinates and the set average area size; when calculating the extreme height of the local solder balls, calculate the maximum height within the set average area range;

[0093] S7. After all the solder balls are measured, according to the height information of the solder balls in the preset area, determine the coplanarity parameters of the chip pins by fitting a plane, and generate a measurement report.

[0094] A method for measuring the height information of chip pin solder balls proposed by the present invention mainly measures the pin height of a packaged chip through visual technology means to solve the current situation of manually measuring each pin one by one with the help of tools. In the present invention, a visual imaging system composed of a projector and an industrial camera is used to calculate and measure all pins at one time, greatly improving the efficiency of measuring the height of chip pin solder balls.

[0095] The present invention also provides a measurement system for the height information of chip pin solder balls. Please refer to Figure 2 as shown, including:

[0096] A data acquisition module, including an image acquisition unit and a projection control unit. The projection control unit is used to project a preset stripe from multiple preset angles onto the packaged chip, and the image acquisition unit is used to obtain multiple stripe phase-shifted images;

[0097] A calibration and measurement module, including an unpacking unit, a calibration unit, and a measurement unit. Among them, the unpacking unit is used for each of the stripe phase-shifted images to determine the first wrapped phase of the preset stripe on the chip pin solder ball according to the stripe phase-shifted image; and use the branch cut method to restore the first wrapped phase into a continuous first absolute phase map;

[0098] The calibration unit is used for each pixel coordinate point in the first absolute phase map to fit and calibrate the absolute phase of the pixel coordinate point by using a calibration block to determine the initial relative height information of the chip pin solder ball;

[0099] The measurement unit is used to superimpose the initial relative height information at different preset angles to obtain the unobstructed relative height information of the chip pin solder ball.

[0100] Furthermore: The projection control unit is also used to project the preset stripe from multiple preset angles onto the calibration block, and the image acquisition unit is also used to obtain multiple calibration stripe phase-shifted images;

[0101] The unpacking unit is also used for each of the calibration stripe phase-shifted images to determine the second wrapped phase of the preset stripe on the calibration block according to the calibration stripe phase-shifted image; and use the branch cut method to restore the second wrapped phase into a continuous second absolute phase map;

[0102] The calibration unit is used for each pixel coordinate point in the second absolute phase map to fit and calibrate the absolute phase of the pixel coordinate point by using the true height value of the calibration block to determine the calibration parameter distribution information at each preset angle; for each pixel coordinate point in the first absolute phase map, use the calibration parameter distribution information at the same preset angle to fit and calibrate the absolute phase of the pixel coordinate point to determine the initial relative height information of the chip pin solder ball.

[0103] Further: The projection control unit is further configured to determine the minimum number of fringe periods according to the true physical size corresponding to a single resolution unit of the projector and in combination with the theoretical height of the solder balls on the chip pins.

[0104] Generate four-step phase-shifted cosine fringes as the preset fringes in combination with the minimum number of fringe periods.

[0105] Further: The image acquisition unit is further configured to acquire a comparison image of the height of the solder balls on the chip pins without fringes.

[0106] The measurement unit is further configured to determine a 2D mask of the solder balls in the preset area on the image according to the comparison image of the height of the solder balls on the chip pins.

[0107] Determine the relative height information of the solder balls in the preset area in combination with the unobstructed relative height information of the solder balls on the chip pins and the 2D mask.

[0108] Further: The measurement unit is further configured to perform preprocessing on the comparison image of the height of the solder balls on the chip pins through mean filtering to obtain a processed intermediate image.

[0109] Extract the solder balls in the preset area in the intermediate image by using a threshold method to generate a 2D mask.

[0110] Further, it further includes:

[0111] A statistical module, configured to determine the coplanarity parameter of the chip pins by fitting a plane according to the height information of the solder balls in the preset area.

[0112] The host computer module is mainly responsible for UI interaction operations, scheduling other modules, and displaying; the user can select left projection measurement calibration or right projection measurement calibration on the interface popped up by the host computer, and can separately control and operate the left and right projection devices to perform calibration respectively.

[0113] The projection control unit projects an image onto the chip surface according to the fringes pre-downloaded to the DLP image acquisition unit according to the set projection timing, and synchronously outputs a trigger signal.

[0114] The image acquisition unit performs the first soft-trigger image acquisition according to the camera exposure parameters set by the host computer module. When adjusted to normal acquisition of fringe images, it is set to the external trigger mode, follows the projector projection timing to acquire fringe images, and sends them to the host computer module, which packs and conveys them to the calibration measurement module.

[0115] The calibration measurement module mainly includes an unpacking unit, a calibration unit, and a measurement unit. The unpacking unit is used to determine the first wrapped phase of the preset stripe on the chip pin solder ball according to the stripe phase-shifted image, and restore the first wrapped phase into a continuous first absolute phase map by using the branch cut method. The calibration unit calibrates the phase-height model parameters of the left and right projection systems through a calibration block. The measurement unit restores the height image according to the stripe images projected by the two projection systems respectively, combined with the calibrated phase-height model parameters, and then calculates the relative height of each solder ball according to the extracted pin solder ball coordinates, and sends it to the host computer system for the statistical module;

[0116] For the described statistical module, after receiving the height information of each pin, according to the output strategy, it can calculate the relative height information of a certain pin of the chip or calculate the coplanarity of the heights of each chip pin, and export a measurement report;

[0117] In summary, the host computer module schedules the projection control unit and the image acquisition unit. Please refer to Figure 3 as shown Figure 3 In the figure, DLP1 and DLP2 are two projection control units respectively, which are used to project stripes from two different preset angles on the left and right. CCD is the image acquisition unit, which is used to take pictures of the chip surface and obtain the stripe phase-shifted image after the projection control unit projects the stripes. First, the image acquisition unit acquires a chip pin solder ball height comparison image without stripes. Secondly, control the left and right projection control units in the projection control unit to project the designed stripes on the pin surface of the BGA chip to be measured in turn, and synchronously control the image acquisition unit to acquire the images with the projected stripes;

[0118] Import the stripe phase-shifted image and the chip pin solder ball height comparison image without stripes into the calibration measurement module, analyze the chip pin solder ball height comparison image without stripes, and extract the 2D mask of the solder balls in the preset area on the image. Analyze the stripe phase-shifted image, calculate the wrapped phase map of the projected stripes through the relative phase relationship, obtain the absolute phase map through the phase unwrapping algorithm, and combine the phase-height relationship calibrated by the system through the phase-height model, so as to restore the initial relative height information of the BGA package chip pins. Superimpose the initial relative height information restored by the left and right groups of projections to eliminate the void invalid areas. Then, using the extracted 2D mask, the unobstructed relative height information of the solder balls in the preset area can be calculated, and the calculated unobstructed relative height information is returned to the host computer module. The phase unwrapping algorithm described here is based on the branch cut method in space to solve the continuous wrapped phase;

[0119] After the host computer module collects the solder ball height information, it is sent to the statistical module. The statistical module calculates information such as 3σ and coplanarity of the BGA chip solder ball height according to the calculation height strategy set by the user, and can export a measurement report.

[0120] The present invention also provides a computer-readable storage medium storing instructions that, when run on a terminal device, cause the terminal device to execute a method for measuring the height information of solder balls on chip pins as described above.

[0121] The present invention also provides an electronic device, including a memory, a processor, and a program stored on the memory and running on the processor, where the processor implements a method for measuring the height information of solder balls on chip pins as described above when executing the program.

[0122] Figure 5 FIG. shows a schematic structural diagram of an electronic device 10 that can be used to implement embodiments of the present invention. The electronic device is intended to represent various forms of digital computers, such as, for example, laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as, for example, personal digital processors, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the present invention described and / or claimed herein.

[0123] As Figure 5 shown, the electronic device 10 includes at least one processor 11, and a memory communicatively connected to at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc. Among them, the memory stores a computer program executable by at least one processor, and the processor 11 can execute various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 into the random access memory (RAM) 13. In the RAM 13, various programs and data required for the operation of the electronic device 10 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. The input / output (I / O) interface 15 is also connected to the bus 14.

[0124] Multiple components in the electronic device 10 are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a magnetic disk, an optical disc, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0125] The processor 11 may be various general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as a method for measuring the height information of the solder balls on the chip pins.

[0126] In some embodiments, a method for measuring the height information of the solder balls on the chip pins may be implemented as a computer program tangibly embodied in a computer-readable storage medium, such as the storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed onto the electronic device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the method for measuring the height information of the solder balls on the chip pins described above may be executed. Alternatively, in other embodiments, the processor 11 may be configured to execute a method for measuring the height information of the solder balls on the chip pins by any other suitable means (e.g., by means of firmware).

[0127] The various embodiments of the systems and techniques described above in this document may be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SOCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include: being implemented in one or more computer programs that may be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a special-purpose or general-purpose programmable processor, and may receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit the data and instructions to the storage system, the at least one input device, and the at least one output device.

[0128] The computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to the processors of general-purpose computers, special-purpose computers, or other programmable data processing devices such that when the computer programs are executed by the processors, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The computer programs may be executed entirely on the machine, partially on the machine, as an independent software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0129] In the context of the present invention, a computer-readable storage medium can be a tangible medium that can contain or store a computer program for use by or in connection with an instruction execution system, apparatus, or device. The computer-readable storage medium can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. Alternatively, the computer-readable storage medium can be a machine-readable signal medium. More specific examples of the machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0130] To provide for interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device for displaying information to the user (e.g., a CRT (cathode ray tube) or an LCD (liquid crystal display)); and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the electronic device. Other kinds of devices can also be used to provide for interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).

[0131] The systems and techniques described herein can be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer having a graphical user interface or a web browser through which the user can interact with an implementation of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0132] A computing system may include a client and a server. The client and the server are generally far from each other and usually interact via a communication network. The relationship between the client and the server is generated by computer programs running on respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or a cloud host, which is a host product in the cloud computing service system, solving the defects of difficult management and weak business scalability existing in traditional physical hosts and VPS services.

[0133] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0134] In the present invention, unless otherwise clearly specified and defined, terms such as "install", "connect", "connection", "fix", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0135] In the description of this specification, the description with reference to terms such as "an embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0136] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for measuring the height information of solder balls on chip pins, characterized in that, Comprising: Obtain a fringe phase-shifted image, where the fringe phase-shifted image is an image obtained by projecting a preset fringe from multiple preset angles onto a chip and then photographing the chip; For each of the fringe phase-shifted images, determine a first wrapped phase of the preset fringe on the solder balls of the chip pins according to the fringe phase-shifted image; Use the branch cut method to restore the first wrapped phase into a continuous first absolute phase map; For each pixel coordinate point in the first absolute phase map, use a calibration block to perform fitting calibration on the absolute phase of the pixel coordinate point to determine the initial relative height information of the chip pin solder balls; Superimpose the initial relative height information at different preset angles to obtain the unobstructed relative height information of the chip pin solder balls.

2. The measuring method of the tin ball height information of the chip pins according to claim 1, characterized in that The step of using a calibration block to perform fitting calibration on the absolute phase of each pixel coordinate point in the first absolute phase map to determine the initial relative height information of the chip pin solder balls includes: Obtain a calibration fringe phase-shifted image, where the calibration fringe phase-shifted image is an image obtained by projecting a preset fringe from multiple preset angles onto a calibration block and then photographing the chip; For each of the calibration fringe phase-shifted images, determine a second wrapped phase of the preset fringe on the calibration block according to the calibration fringe phase-shifted image; Use the branch cut method to restore the second wrapped phase into a continuous second absolute phase map; For each pixel coordinate point in the second absolute phase map, use the true height value of the calibration block to perform fitting calibration on the absolute phase of the pixel coordinate point to determine the calibration parameter distribution information at each preset angle; For each pixel coordinate point in the first absolute phase map, use the calibration parameter distribution information at the same preset angle to perform fitting calibration on the absolute phase of the pixel coordinate point to determine the initial relative height information of the chip pin solder balls.

3. A method for measuring the height information of solder balls on chip pins according to claim 1, characterized in that, The generation steps of the preset fringe include: According to the true physical size corresponding to a single resolution unit of the projector, combined with the theoretical height of the chip pin solder balls, determine the minimum number of fringe periods; Combined with the minimum number of fringe periods, generate four-step phase-shifted cosine fringes as the preset fringe.

4. The measuring method of the tin ball height information of the chip pins according to claim 1, characterized in that Also included: Obtain a height comparison image of the chip pin solder balls without fringes; According to the height comparison image of the chip pin solder balls, determine a 2D mask of the solder balls in the preset area on the image; Combined with the unobstructed relative height information of the chip pin solder balls and the 2D mask, determine the relative height information of the solder balls in the preset area.

5. The measuring method for the height information of the solder balls on the chip pins according to claim 4, characterized in that, According to the height comparison image of the chip pin solder balls, determining a 2D mask of the solder balls in the preset area on the image includes: According to the height comparison image of the chip pin solder balls, perform preprocessing through mean filtering to obtain a processed intermediate image; Use the threshold method to extract the solder balls in the preset area in the intermediate image to generate a 2D mask.

6. The measuring method for the height information of the solder balls on the chip pins according to claim 4, wherein Also included: According to the height information of the solder balls in the preset area, determine the coplanarity parameters of the chip pins by fitting a plane.

7. A measurement system for the height information of chip pin solder balls, characterized in that, Comprising: A data acquisition module, including an image acquisition unit and a projection control unit, wherein the projection control unit is configured to project preset stripes from multiple preset angles onto a packaged chip, and the image acquisition unit is configured to capture multiple fringe phase-shifted images; A calibration measurement module, including an unpacking unit, a calibration unit, and a measurement unit. Among them, the unpacking unit is configured to, for each of the fringe phase-shifted images, determine a first wrapped phase of the preset stripes on the chip pin solder balls according to the fringe phase-shifted image; Use the branch cut method to restore the first wrapped phase into a continuous first absolute phase map; The calibration unit is configured to, for each pixel coordinate point in the first absolute phase map, use a calibration block to perform fitting calibration on the absolute phase of the pixel coordinate point to determine the initial relative height information of the chip pin solder balls; The measurement unit is configured to superimpose the initial relative height information at different preset angles to obtain the unobstructed relative height information of the chip pin solder balls.

8. A measuring system for the height information of solder balls on chip pins according to claim 7, characterized in that Including: The projection control unit is further configured to project preset stripes from multiple preset angles onto a calibration block, and the image acquisition unit is further configured to capture multiple calibration fringe phase-shifted images; The unpacking unit is further configured to, for each of the calibration fringe phase-shifted images, determine a second wrapped phase of the preset stripes on the calibration block according to the calibration fringe phase-shifted image; Use the branch cut method to restore the second wrapped phase into a continuous second absolute phase map; The calibration unit is configured to, for each pixel coordinate point in the second absolute phase map, use the true height value of the calibration block to perform fitting calibration on the absolute phase of the pixel coordinate point to determine the calibration parameter distribution information at each preset angle; for each pixel coordinate point in the first absolute phase map, use the calibration parameter distribution information at the same preset angle to perform fitting calibration on the absolute phase of the pixel coordinate point to determine the initial relative height information of the chip pin solder balls.

9. A computer-readable storage medium, characterized in that, Instructions are stored in the computer-readable storage medium, and when the instructions are run on a terminal device, the terminal device is caused to execute a method for measuring the height information of chip pin solder balls according to any one of claims 1 to 6.

10. An electronic device, comprising a memory, a processor, and a program stored on the memory and running on the processor, characterized in that, When the processor executes the program, it implements a method for measuring the height information of chip pin solder balls according to any one of claims 1 to 6.

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