Flip-chip defect ultrasonic nondestructive testing system and method
By designing an ultrasonic non-destructive testing system for flip-chip defects and utilizing a three-dimensional motion control system for internal chip defect detection, this system solves the problems of existing detection methods being greatly affected by the external environment, having insufficient resolution, and being harmful to the human body. It achieves efficient, accurate, and non-destructive chip defect detection and possesses independent design capabilities.
Patent Information
- Application Number
- CN202511283691.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-09
- Publication Date
- 2025-12-09
AI Technical Summary
Existing technologies for detecting defects in electronic products, especially in chips, suffer from several drawbacks: detection methods are greatly affected by the external environment, have insufficient resolution, cannot pinpoint the depth of defects, and are harmful to human health. Furthermore, high-end equipment relies on imports, which restricts independent design and integration.
Design an ultrasonic non-destructive testing system for defects in flip-chip, including a host computer, a pulse transceiver, a data acquisition card, an ultrasonic sensor, a displacement platform, a three-dimensional motion platform, and a motion controller. The three-dimensional motion control system realizes the transmission, reception, and image conversion of ultrasonic signals, and performs overall chip inspection, avoiding damage to the chip from current, temperature, electromagnetic fields, and X-rays.
It achieves efficient and accurate detection of internal defects in chips, improves detection efficiency, is non-destructive and safe for human use, can identify multiple defect types, is unaffected by the external environment, and has independent design capabilities.
Smart Images
Figure CN121090684A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of ultrasonic nondestructive testing, and particularly relates to an ultrasonic nondestructive testing system and method for flip-chip defects. BACKGROUND
[0002] With the rapid development of machines towards automation and intelligence, the requirements for electronic products, such as smaller size, lighter weight, more functions, faster speed, and safer reliability, promote the packaging of components and devices to develop in the direction of high density and multi-function. During the later stage of the service of machines, due to the influence of external temperature, impact, vibration and other factors, the soldering deviation and insufficient solder joints are prone to crack and continuously expand, leading to the failure of electronic components and devices, and according to statistics, the proportion is more than 50%. Therefore, before the service of machines, the solder joint defect detection of electronic systems is required to exclude faults, and the high-precision nondestructive testing technology becomes particularly important.
[0003] Common nondestructive testing methods for internal defects of chips include thermal imaging, X-ray detection and ultrasonic nondestructive testing. The thermal imaging technology uses a thermal imager to sense and measure the infrared radiation emitted by the chip, so as to obtain the distribution image of the chip surface. The thermal imaging method does not need to be in direct contact with the measured object, has fast detection speed and strong real-time performance, but the detection result is easily affected by the external environment, and the spatial resolution is poor. The X-ray detection technology uses the principle that the energy is absorbed or scattered by different parts inside the chip to form an X-ray image. The X-ray detection technology is nondestructive to the object, has high sensitivity and high resolution, and can display the internal plane of the object, but it cannot locate the defect depth, and the X-ray is harmful to the human body, and the protection cost is high.
[0004] In the field of industrial production and manufacturing, the ultrasonic nondestructive testing technology has strong penetration, fast speed, high accuracy and high efficiency, and is widely used in many fields, such as concrete crack detection, generator blade defect detection, internal defect detection of electronic components and devices, and body welding casting defect detection, especially the nondestructive testing of internal defects of chips, which can improve the stability and reliability of the control terminal. The ultrasonic nondestructive testing technology detects macroscopic defects and measures geometric characteristics of the chip through the interaction between ultrasonic waves and the internal structure of the chip, realizes the visualization of the internal three-dimensional structure of the chip, and has the advantages of strong penetration, high sensitivity, accurate defect positioning, low detection cost and fast speed. However, the key devices and high-end equipment related to the ultrasonic nondestructive testing system technology depend on imports, and are restricted in designability and integrability, and it is urgent to realize the self-innovation of design and preparation technology. SUMMARY
[0005] In order to overcome the prior art, the present application provides a flip-chip defect ultrasonic nondestructive testing system and method, comprising a host computer, a pulse transceiver, a collection card, an ultrasonic sensor, a displacement platform, a three-dimensional motion platform and a motion controller; the host computer serves as a control platform responsible for issuing control instructions and data processing; the pulse transceiver, the collection card and the high-frequency ultrasonic sensor constitute a signal acquisition and transmission platform responsible for ultrasonic signal transmission, reception, transmission and analog-to-digital conversion; the displacement platform is used for fixing the flip-chip; the three-dimensional motion platform and the motion controller constitute a three-dimensional motion control system responsible for carrying out scanning at different spatial positions by the ultrasonic sensor. The present application detects the chip as a whole, without detecting the solder joints one by one, which can greatly improve the defect detection efficiency.
[0006] The technical scheme adopted by the present application to solve its technical problems is as follows:
[0007] A flip-chip defect ultrasonic nondestructive testing system, comprising a host computer, a pulse transceiver, a collection card, an ultrasonic sensor, a displacement platform, a three-dimensional motion platform and a motion controller;
[0008] The host computer serves as a control platform responsible for issuing control instructions and data processing;
[0009] The pulse transceiver, the collection card and the high-frequency ultrasonic sensor constitute a signal acquisition and transmission platform responsible for ultrasonic signal transmission, reception, transmission and analog-to-digital conversion;
[0010] The displacement platform is used for fixing the flip-chip;
[0011] The three-dimensional motion platform and the motion controller constitute a three-dimensional motion control system responsible for carrying out scanning at different spatial positions by the ultrasonic sensor.
[0012] Preferably, the control of each module of the detection system is completed through a serial port.
[0013] Preferably, the three-dimensional motion control system has the function of moving along the X, Y and Z axes.
[0014] Preferably, the distance between the flip-chip and the ultrasonic sensor is 0.5mm-5mm, and when the ultrasonic sensor is moved, it is ensured that the surface of the flip-chip does not touch the end of the ultrasonic sensor.
[0015] Preferably, the types of solder joint defects include missing solder joints, bridging solder joints, offset solder joints, virtual solder joints and solder joint cracks.
[0016] Preferably, the scanning ranges of the X and Y axes of the three-dimensional motion control system are 500mm and 300mm respectively, the highest resolution reaches 0.1μm, and the scanning range of the Z axis is 10mm, the highest resolution reaches 10μm.
[0017] Preferably, the ultrasonic sensor mounted on the three-dimensional motion control system is detachable.
[0018] Preferably, the detection frequency range of the ultrasonic sensor is 0.1-200 MHz, reaching the ultra-high frequency range.
[0019] An ultrasonic non-destructive testing method for flip-chip defects, comprising the following steps:
[0020] Step 1: Fix the ultrasonic sensor on the three-dimensional motion control system, and place the packaged flip-chip in a water tank filled with deionized water;
[0021] Step 2: Move the ultrasonic sensor above the flip-chip and the displacement platform, with the flip-chip located between the ultrasonic sensor and the displacement platform, adjust the positions of the ultrasonic sensor and the displacement platform so that the center point of the flip-chip and the ultrasonic sensor are located on the same vertical line;
[0022] Step 3: Turn on the ultrasonic sensor, and set the scanning parameters to adjust the scanning range and accuracy of the flip-chip;
[0023] Step 4: Collect and measure the signals reflected from the flip-chip by the ultrasonic sensor, and convert the collected acoustic information into images by the image processor;
[0024] Step 5: Adjust the definition and grayscale of the images, and determine the defect type by comparing with the detection schematic diagram, to determine whether the solder joint has defects and the defect type.
[0025] The beneficial effects of the present application are as follows:
[0026] (1) The present application uses ultrasonic waves to detect defects in flip-chip, without applying current, temperature, electromagnetic, X-ray, etc. to the flip-chip, without damaging the components of the device, and harmless to the human body.
[0027] (2) The present application does not need to rotate or tilt the flip-chip, only needs to adjust the distance between the displacement platform and the ultrasonic sensor.
[0028] (3) The present application uses the ultrasonic sensor to emit ultrasonic waves to the sample, and analyzes the echo signals to obtain the internal information of the chip, realizing the three-dimensional imaging of the chip. In the prior art, the images of the internal via, pad, and solder joint of the device overlap during the rotation and tilting of the device, which cannot realize the imaging of the internal structure of the chip, affecting the accuracy of defect detection.
[0029] (4) The present application detects the chip as a whole, without the need for one-by-one detection of the solder joint, which can greatly improve the detection efficiency of defects.
[0030] (5) The ultrasonic sensor of the present application can be freely disassembled and selected with different center frequencies, and can realize detection of defects of different sizes and types.
[0031] (6) The defect detection method of the present application detects the overall flip-chip, has the characteristics of non-destructive, high defect recognition, high detection efficiency, simple defect judgment, etc., and through further processing of ultrasonic imaging data, the self-recognition of the solder joint defect can be realized, which greatly enhances the defect detection capability and efficiency of the flip-chip device, especially the solder joint missing, solder joint offset, and especially the solder joint virtual welding. BRIEF DESCRIPTION OF DRAWINGS
[0032] Figure 1 The figure is a schematic diagram of the system of the present application.
[0033] Figure 2 The figure is a schematic diagram of the different types of defect detection provided by the embodiment of the present application.
[0034] BRIEF DESCRIPTION OF DRAWINGS: motion controller 1, host computer 2, acquisition card 3, pulse transceiver 4, ultrasonic sensor 5, water tank 6, flip-chip 7, displacement platform 8, first solder joint 9, second solder joint 10, third solder joint 11, fourth solder joint 12, fifth solder joint 13, and sixth solder joint 14. DETAILED DESCRIPTION
[0035] The present application will be further described below in combination with the drawings and embodiments.
[0036] The present application aims to design a detection system, so that the system realizes A-scan, B-scan, C-scan, X-scan and other ultrasonic scanning imaging modes, successfully applies to three-dimensional imaging of the internal structure of the chip, and provides a new method and way for the detection of flip-chip solder joint defects.
[0037] As Figure 1 , in order to achieve the above-mentioned purpose, the present application provides a flip-chip defect ultrasonic non-destructive testing system, which mainly includes a host computer, a pulse transceiver, an acquisition card, an ultrasonic sensor, a displacement platform, a three-dimensional motion platform and a motion controller, wherein the host computer serves as a control platform responsible for issuing control instructions and data processing; the pulse transceiver, the acquisition card and the high-frequency ultrasonic sensor form a signal acquisition and transmission platform, responsible for the transmission, reception, transmission and analog-to-digital conversion of ultrasonic signals; the three-dimensional motion platform and the motion controller form a three-dimensional motion control system, responsible for carrying out scanning of the ultrasonic sensor at different spatial positions, the synchronization between hardware modules is realized through the position comparison function of the motion controller, and the control of the system on the hardware is completed through the communication interface such as serial port.
[0038] A flip-chip defect ultrasonic non-destructive testing method, comprising the following steps:
[0039] Step 1, fix the high-frequency ultrasonic sensor on the three-dimensional motion control system, and place the packaged flip-chip in the water tank filled with deionized water;
[0040] Step 2, move the ultrasonic sensor above the flip-chip and the displacement platform, adjust the positions of the ultrasonic sensor and the displacement platform so that the flip-chip is perpendicular to the ultrasonic sensor;
[0041] Step 3, turn on the ultrasonic sensor, and adjust the scanning range and accuracy of the flip-chip by setting the scanning parameters of the three-dimensional motion control system;
[0042] Step 4, collect and measure the signals reflected from the flip-chip by the ultrasonic sensor, and convert the collected acoustic information into images by the image processor;
[0043] Step 5, adjust the clarity and grayscale of the images, and determine the defect type by comparing with the detection diagram, to determine whether the solder joint has defects and the defect type.
[0044] The three-dimensional motion control system has the function of moving along the X, Y, and Z axes, and when the ultrasonic sensor is in the vertical position, the displacement platform ensures that the flip-chip is perpendicular to the ultrasonic sensor.
[0045] Adjust the distance between the flip-chip and the ultrasonic sensor to 0.5-5 mm, and ensure that the surface of the flip-chip does not touch the end of the ultrasonic sensor when moving the ultrasonic sensor.
[0046] The defect types of the solder joint include missing solder joint, solder joint bridging, solder joint offset, solder joint virtual welding, and solder joint crack.
[0047] The scanning range of the X and Y axes of the three-dimensional motion control system is 500 mm and 300 mm respectively, and the highest resolution can reach 0.1 μm, the scanning range of the Z axis is 10 mm, and the highest resolution can reach 10 μm, and multiple mode imaging such as A, B, C, and X can be performed.
[0048] The ultrasonic sensor installed on the three-dimensional motion platform and the motion controller is detachable.
[0049] The detection frequency range of the ultrasonic sensor is 0.1-200 MHz, which can reach the ultra-high frequency (>100 MHz) range.
[0050] Embodiment:
[0051] The ultrasonic sensor emits ultrasonic waves to the sample, and the greater the difference in acoustic resistance of the two media, the greater the difference in the quality of the medium, and the greater the change in the speed of sound, the greater the ultrasonic wave reflection ability, the greater the ultrasonic sensor receives the reflected acoustic energy from the surface of the imaging object, and the internal information of the chip is obtained by analyzing the echo signal to realize the three-dimensional imaging of the chip. The solder joint with defects has a discontinuous welding material, which causes a significant change in the acoustic impedance in the solder joint range, so that the received echo signal intensity is different, and the gray scale distribution map is obtained by offline processing the echo signal.
[0052] As shown in Figure 2 The displacement platform 8 can fix the flip-chip 7, and the chip needs to be fixed on the object table by bonding. The displacement platform 8 can move along the three-axis direction, and can adjust the position of the chip to ensure that the surface of the chip is parallel to the X and Y axis movement planes of the ultrasonic sensor 5.
[0053] The ultrasonic sensor 5 can generate ultrasonic waves. By replacing the ultrasonic sensor 5, the parameters (center frequency, bandwidth, focal length, resolution, etc.) of the ultrasonic waves can be adjusted. The ultrasonic sensor 5 can move vertically along the Z-axis direction, and the focal point position of the ultrasonic sensor 5 can be adjusted to be in the imaging plane.
[0054] The ultrasonic sensor 5 is perpendicular to the surface of the chip and the displacement platform 8. The ultrasonic sensor 5 receives the reflected echo from the chip to perform imaging, and judges whether the chip solder joint has defects according to the image.
[0055] The flip-chip solder joint defect nondestructive detection method of the application comprises the following steps:
[0056] (1) Fix the device on the displacement platform 8 and place it at the bottom of the water tank 6 to ensure that the deionized water completely floods the surface of the chip. The displacement platform 8 has the ability to move along the X, Y and Z three-axis directions. When the chip is fixed, the surface of the chip faces the ultrasonic sensor 5 and the surface of the chip is perpendicular to the ultrasonic sensor;
[0057] (2) Slowly adjust the angle of the displacement platform 8 to make the ultrasonic sensor 5 perpendicular to the displacement platform 8 and the surface of the chip. Adjust the distance between the surface of the chip and the ultrasonic sensor 5 to 0.5mm-5mm. When moving the device, ensure that the surface of the chip does not touch the end of the ultrasonic sensor 5;
[0058] (3) Select the center frequency of the ultrasonic sensor 5 as 100MHz, the bandwidth as 100%, and the focal length as 2mm. Turn on the pulse transmitter. Perform continuous scanning detection. First, the upper computer 2 sends configuration parameters and control instructions to all other hardware. Then the motion controller 1 sends step pulses to the three-dimensional motion control system according to the scanning instructions to realize scanning motion in different trajectories.
[0059] (4) During the scanning process, the three-dimensional motion control system feeds back its position information to the motion controller 1, and then the motion controller 1 generates a position synchronization signal and transmits it to the pulse transceiver 4 and the acquisition card 3.
[0060] (5) The trigger mode of the pulse transceiver 4 and the acquisition card 3 is set to external triggering. After receiving the position synchronization signal, the pulse transceiver 4 transmits an excitation signal to the ultrasonic sensor 5 and receives the echo signal from the ultrasonic sensor 5, and the acquisition card 3 converts the analog echo signal from the pulse transceiver 4 into a digital signal. The host computer 2 processes the digital signal to convert it into an image.
[0061] (6) After processing by the host computer 2, the solder joint distribution image is displayed, and the spacing between the chip surface and the ultrasonic sensor 5 and the image grayscale are further adjusted to obtain images of different depths inside the chip. By comparing with the detection schematic, the presence or absence of defects and the type of defects of the solder joint are determined. The solder joint detection schematic is as follows:
[0062] For qualified devices, the sixth solder joint 14 presents a regular circular shape and the size is basically consistent, and the position of the sixth solder joint 14 is consistent with the actual distribution of the solder joint;
[0063] For missing solder joints, since there is no second solder joint 10 at this position, the space originally occupied by the solder joint is completely occupied by the bottom filling glue, making the image show that this part presents high contrast (white);
[0064] For solder joint bridging, the solder of the first solder joint 9 in the adjacent position is combined in the middle area, presenting a "strip-shaped" connection structure, and the soldering material is connected to the adjacent solder joint. Therefore, the black image representing the position of the first solder joint 9 in the image increases, and the position of the first solder joint 9 may remain in place or may shift slightly;
[0065] For solder joint offset, the image shows that the third solder joint 11 has a significant offset compared to the original position;
[0066] For solder joint virtual welding, since the fourth solder joint 12 does not make full contact, only the central part of the solder joint realizes welding, causing the solder joint to be suspended around the pad, so that the bottom filling glue can enter the area not contacted by the fourth solder joint 12, forming a virtual solder joint, which appears as a decrease in the area of the black image on the image, and the smaller the area, the more serious the virtual welding;
[0067] For solder joint cracking, the image shows that there is a gap between the fifth solder joint 13 and the chip, which appears as a high-contrast (white) linear pattern on the image, and the larger the area, the larger the crack;
[0068] The method has the advantages that the ultrasonic nondestructive testing device and method do not apply current, temperature, electromagnetic, X-ray and the like to the flip-chip, are nondestructive to each component of the device, and are harmless to the human body; in addition, the device can be freely disassembled and replaced with ultrasonic sensors of different center frequencies, internal information of the chip is obtained by analyzing echo signals received by the ultrasonic sensors, three-dimensional imaging of the chip interior can be realized, each solder joint does not need to be detected one by one, and the detection efficiency of different defects can be greatly improved.
Claims
1. An ultrasonic non-destructive testing system for defects in flip-chip bonding, characterized in that, It includes a host computer, pulse transceiver, data acquisition card, ultrasonic sensor, displacement platform, three-dimensional motion platform, and motion controller; The host computer, acting as a control platform, is responsible for issuing control commands and processing data. The pulse transceiver, acquisition card, and high-frequency ultrasonic sensor constitute a signal acquisition and transmission platform, which is responsible for the transmission, reception, transmission, and analog-to-digital conversion of ultrasonic signals. The displacement platform is used to fix the flip-chip. The three-dimensional motion platform and motion controller together form a three-dimensional motion control system, which is responsible for carrying ultrasonic sensors to perform scanning at different spatial positions.
2. The ultrasonic non-destructive testing system for defects in flip-chip bonding according to claim 1, characterized in that, The detection system controls each module via a serial port.
3. An ultrasonic non-destructive testing system for defects in flip-chip bonding according to claim 1, characterized in that, The three-dimensional motion control system has the function of moving along the X, Y, and Z axes.
4. An ultrasonic non-destructive testing system for defects in flip-chip bonding according to claim 1, characterized in that, The distance between the flip-chip and the ultrasonic sensor is 0.5mm to 5mm, ensuring that the surface of the flip-chip does not touch the end of the ultrasonic sensor when the ultrasonic sensor is moved.
5. An ultrasonic non-destructive testing system for defects in flip-chip bonding according to claim 1, characterized in that, The types of solder joint defects include missing solder joints, solder joint bridging, solder joint misalignment, solder joint cold solder joints, and solder joint cracks.
6. An ultrasonic non-destructive testing system for defects in flip-chip bonding according to claim 1, characterized in that, The X-axis and Y-axis scanning ranges of the three-dimensional motion control system are 500mm and 300mm respectively, with a maximum resolution of 0.1μm. The Z-axis scanning range is 10mm, with a maximum resolution of 10μm.
7. An ultrasonic non-destructive testing system for defects in flip-chip bonding according to claim 1, characterized in that, The ultrasonic sensor installed in the three-dimensional motion control system is detachable.
8. An ultrasonic non-destructive testing system for defects in flip-chip bonding according to claim 1, characterized in that, The ultrasonic sensor has a detection frequency range of 0.1MHz-200MHz, and can reach ultra-high frequency, i.e., >100MHz.
9. A testing method using the ultrasonic nondestructive testing system as described in claim 1, characterized in that, Includes the following steps: Step 1: Fix the ultrasonic sensor onto the three-dimensional motion control system, and place the packaged flip-chip in a water tank filled with deionized water; Step 2: Move the ultrasonic sensor above the flip-chip and the displacement platform. The flip-chip is located between the ultrasonic sensor and the displacement platform. Adjust the position of the ultrasonic sensor and the displacement platform so that the center point of the flip-chip and the ultrasonic sensor are on the same vertical line. Step 3: Turn on the ultrasonic sensor and adjust the scanning range and accuracy of the flip-chip by setting the scanning parameters; Step 4: The ultrasonic sensor collects and measures the signal reflected from the flip-chip, and the image processor converts the collected acoustic information into an image. Step 5: Adjust the image clarity and grayscale, and determine the defect type by referring to the inspection diagram to determine whether there are defects in the solder joint and the type of defects.