A chip circuit defect detection system and method based on terahertz on-chip spectroscopy

Abstract

The present invention provides a chip circuit defect detection system and method based on terahertz on-chip spectroscopy. The system includes: a laser for generating femtosecond laser light; a spectroscope for splitting the femtosecond laser light into transmitted light and received light; a transmitting end for generating terahertz waves upon incident light, which are coupled and transmitted to a receiving end; a receiving end for incident light and for generating a current signal based on the received light and the terahertz wave; and a radio frequency probe for transmitting the current signal to the chip to be detected. The present invention transforms traditional far-field detection into near-field detection by coupling terahertz waves transmitted from the transmitting end to the receiving end to generate a current signal for detection at the receiving end. This not only significantly improves the signal-to-noise ratio and transmission efficiency, but also is applicable to higher-frequency terahertz waves, effectively improving detection accuracy.

Description

Technical Field

[0001] The present invention relates to the field of chip detection technology, and in particular to a chip circuit defect detection system and method based on terahertz on-chip spectroscopy. Background Art

[0002] The rapid development of integrated circuits is placing increasingly stringent demands on back-end packaging and testing. Chips are moving towards low power consumption, integration, high speed, and miniaturization. The miniaturization of integrated circuits has led to more complex and diverse internal chip wiring, while the three-dimensional development has also posed significant technical challenges for failure analysis. Consequently, packaging and testing technology has been hailed as one of the fastest-growing technologies in recent years. With the continuous advancement of 2.5D and 3D packaging technologies, many new packaging technologies have emerged, such as system-in-package (SiP), through-silicon via (TSV), and wafer-level packaging (3D WLP). These complex and diverse packaging technologies have created new challenges in the manufacturing process, leading to increased defects and damage during the process.

[0003] Electrical failure analysis is the first step in analyzing IC package failures. Its purpose is to detect the electrical performance between chip pins, as well as any abnormal open circuits, short circuits, and current leakage that may exist between the pins. Subsequent physical failure analysis of the IC package can then be performed using optical microscopy, ultrasonic imaging, thermal imaging, and radiographic imaging. Traditional failure analysis methods have two main problems. First, for advanced processes, commonly used detection methods lack resolution, making it difficult to detect defects at smaller scales, such as tens of microns. Second, detection time is long. For imaging testing, ultrasonic or X-ray methods are commonly used, but ultrasonic testing requires the introduction of a medium, and large-area testing is necessary for unknown defects. X-ray testing is less effective for detecting cracks and air layers, and its resolution is also insufficient.

[0004] Circuit fault detection for chips based on terahertz waves involves transmitting terahertz waveforms with rising edges in the femtosecond range and time jitter in the picosecond range. Therefore, it can handle defects with an accuracy ranging from a few microns to tens of microns. Furthermore, since the detection is waveform-based, it does not require the extensive time consumption of traditional imaging-based detection, resulting in improved timeliness. However, existing circuit fault detection using terahertz waves utilizes vector network analyzers. The low frequency of the terahertz waves generated by vector network analyzers makes it difficult to further improve the accuracy of detectable defects. Furthermore, existing terahertz wave detection is far-field, requiring the terahertz waves to be transmitted and received into free space. This results in high signal noise and low transmission efficiency. Furthermore, the antenna is typically several centimeters to more than ten centimeters in size, with the transmission end even reaching tens of centimeters in size, increasing the size of the detection equipment. Summary of the Invention

[0005] To address the above problems, the present invention proposes a chip circuit defect detection system and method based on terahertz on-chip spectroscopy. The system focuses the emitted light on the terahertz wave generated at the transmitting end and couples it to the receiving end. The receiving end then generates an electrical signal based on the received light and the coupled terahertz wave. Finally, the terahertz wave is input into the chip through a radio frequency probe to complete the chip detection. This not only enables higher frequency terahertz wave detection and effectively improves detection accuracy, but also the transmission of electrical signals belongs to near-field detection. Compared with free space transmission and reception, it can significantly improve the signal-to-noise ratio and transmission efficiency, and the entire transmission structure and detection system are more compact.

[0006] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0007] A chip circuit defect detection system based on terahertz on-chip spectroscopy, comprising:

[0008] A laser for generating femtosecond laser light;

[0009] A beam splitter, used for splitting the femtosecond laser into emitted light and received light;

[0010] A transmitting end, configured to generate a terahertz wave after the incident emission light, and couple the terahertz wave to a receiving end;

[0011] a receiving end, configured to receive the incident light and generate a current signal based on the received light and the terahertz wave;

[0012] The radio frequency probe is used to transmit the terahertz signal generated by the transmitter to the chip to be tested.

[0013] In this technical solution, the detection system's laser emits a femtosecond laser. After being split by a beam splitter, the femtosecond laser produces emitted light for the transmitting end and received light for the receiving end. The emitted light, after being focused and incident on the transmitting end, generates a terahertz wave, which is coupled and transmitted to the receiving end. Upon receipt of the terahertz wave by the receiving end, the terahertz wave's electric field excites the carriers in the receiving end chip to produce directional motion. Simultaneously, under the influence of the received light, an electrical signal is generated, which is amplified by a current amplifier, forming a current signal at the receiving end. Ultimately, the terahertz signal is transmitted to the radio frequency probe and further to the chip under test.

[0014] During detection, the RF probe contacts the chip to be detected, and the generated terahertz wave signal is transmitted to the inside of the chip through the RF probe. When encountering an impedance mismatch condition, a detection echo signal is returned. By comparing the difference in waveform between the standard echo signal and the detection echo signal, it can be determined whether the chip to be detected is faulty, the fault type and the fault location.

[0015] This technical solution transforms traditional far-field detection into near-field detection by coupling terahertz waves transmitted from the transmitter to the receiver, generating a current signal for detection at the receiver. This significantly improves the signal-to-noise ratio and transmission efficiency and is also applicable to higher-frequency terahertz waves, effectively increasing detection accuracy. Furthermore, since the signal transmission end of this signal transmission method is not in free space, the detection system can use a smaller antenna for transmission. This makes the entire transmission and detection system more compact, further improving transmission efficiency and ensuring effective transmission coupling.

[0016] Furthermore, the transmitting end includes a transmitting antenna and two mutually parallel first transmission lines connected to the transmitting antenna, and the first transmission lines are connected to a DC bias source; the receiving end includes a receiving antenna and two mutually parallel second transmission lines connected to the receiving antenna, and the second transmission lines are connected to the radio frequency probe, and an ammeter for weak signal amplification is also provided on the second transmission lines.

[0017] In this technical solution, the transmitting antenna at the transmitting end is arranged on two first transmission lines extending parallel to each other. The transmitting antenna is preferably made of a terahertz transmitting chip material, such as an InGaAs / InAlAs superlattice material. Preferably, the transmitting antenna substrate is InP with a thickness of 1μm to 5μm and a period of 50 to 150 layers. A DC bias source is also connected to the first transmission line to apply an adjustable DC bias to both ends of the transmitting antenna. When the emitted light is focused and incident on the transmitting antenna, activating the carriers, the DC bias causes the carriers to move in a directional manner, thereby radiating terahertz waves.

[0018] The receiving antenna at the receiving end is arranged on two second transmission lines extending parallel to each other. The receiving antenna is preferably made of InGaAs or InAlAs superlattice material. The terahertz wave generated by the transmitting end can be coupled and transmitted to the second transmission line at the receiving end while traveling along the first transmission line. It is then transmitted to the receiving antenna, where it interacts with the received light to form a current signal. A galvanometer connected to the second transmission line is used to detect the current signal. A current amplifier is also connected to the second transmission line to amplify the current signal for detection.

[0019] In order to improve the coupling transmission efficiency of terahertz waves and reduce crosstalk between transmission lines, the distance between adjacent first and second transmission lines is 5μm~20μm. Preferably, the distance between the first and second transmission lines is 5μm~10μm.

[0020] The signal transmission structure in this technical solution allows the transmitting and receiving antennas to use antenna materials with a size of millimeters, and the distance between each transmission line reaches the micron level, so that the area of ​​the entire signal transmission structure is only millimeters in size, which is much smaller than the transmission structure of tens of centimeters in the existing technology. It effectively ensures effective transmission efficiency and transmission coupling, and at the same time greatly reduces the transmission structure and volume of the detection system.

[0021] Furthermore, the four transmission lines can be arranged parallel to each other and extend in a straight line. This structure is simpler. If the loss of the terahertz wave coupled between the first and second transmission lines is desired to be minimized, the distance between the first and second transmission lines should be smaller. If the crosstalk generated by the terahertz wave on the first transmission line is desired to be minimized, the distance between the first and second transmission lines should be larger. Therefore, it is preferred that the first transmission line be arranged in a multi-segment structure.

[0022] Furthermore, the first transmission line is parallel to the second transmission line, the first transmission line includes a coupled transmission section and an uncoupled transmission section, and the distance between the coupled transmission section and the second transmission line is smaller than the distance between the uncoupled transmission section and the second transmission line.

[0023] In this technical solution, the first transmission line has a multi-segment structure, which includes a coupled transmission segment and an uncoupled transmission segment. All areas of the first transmission line except the coupled transmission segment are uncoupled transmission segments, wherein the distance between each point on the coupled transmission segment and the second transmission line is closer, while the distance between each point on the uncoupled transmission segment and the second transmission line is farther. By providing the coupled transmission segment, the distance between the first and second transmission lines can be made closer, reducing the transmission loss of the terahertz wave and improving the transmission efficiency. Preferably, the transmitting antenna can be provided in the coupled transmission segment to achieve efficient coupling of the terahertz wave to the second transmission line after it is generated. At the same time, the distance between the uncoupled transmission segment on the first transmission line and the second transmission line can be set farther, significantly reducing the crosstalk caused by the terahertz wave on the second transmission line when propagating in the uncoupled transmission segment, while achieving high transmission efficiency and low crosstalk of the terahertz wave, which is conducive to further improving the accuracy of detection.

[0024] Preferably, the distance between the coupled transmission section and the second transmission line may be 5 μm to 20 μm, and the distance between the uncoupled transmission section and the second transmission line may be 15 μm to 50 μm.

[0025] Furthermore, the coupled transmission segment includes a transmission segment parallel to the second transmission line and a connection segment connected between the transmission segment and the uncoupled transmission segment, and the distance between the transmission segment and the second transmission line is 5 μm-10 μm.

[0026] In this technical solution, the transmission segment of the coupled transmission section is primarily used for terahertz wave coupling, and the connecting segment is used to connect the transmission segment with the uncoupled transmission segment. The transmission segment must be parallel to the second transmission line, and preferably, the distance between the transmission segment and the second transmission line is 5μm to 10μm. The connecting segment can be configured in a variety of ways, extending along a straight line, a broken line, or a curve. Different configurations of the connecting segment also affect the final form of the coupled transmission segment.

[0027] Preferably, the connecting segment is a straight line or a curve.

[0028] Preferably, the connecting section is a straight line, and the angle between the connecting section and the transmission section is a right angle.

[0029] Preferably, the connecting segment may also be a curve.

[0030] Furthermore, the first angle between the transmission segment and the connecting segment, and the second angle between the connecting segment and the uncoupled transmission segment, are both obtuse angles. In this technical solution, by setting the first and second angles to obtuse angles, compared to right angles, the loss of terahertz waves propagating along the first transmission line can be reduced, further improving the transmission efficiency of terahertz waves.

[0031] Furthermore, the coupling transmission section is located on a side of the receiving antenna away from the radio frequency probe. In this technical solution, the terahertz wave coupled to the second transmission line via the coupling transmission section can better act on the received light focused by the receiving antenna.

[0032] Furthermore, the first transmission line and the second transmission line are provided with photonic bandgap filters. The photonic bandgap filters provided on the first and second transmission lines can eliminate the echo of the reflected signal during the detection process, thereby more effectively detecting the detection echo signal returned by the chip to be detected.

[0033] Another object of the present invention is to provide a chip circuit defect detection method based on terahertz on-chip spectroscopy. This method is based on a special terahertz signal transmission method and can achieve higher-frequency terahertz wave detection, significantly improving the signal-to-noise ratio and transmission efficiency compared to traditional far-field detection.

[0034] Specifically, a chip circuit defect detection method based on terahertz on-chip spectroscopy includes the following steps:

[0035] generating a femtosecond laser, wherein the femtosecond laser is split into an emission light and a reception light;

[0036] The transmitted light is incident on the transmitting antenna to generate a terahertz wave that is transmitted along the first transmission line. The terahertz wave is coupled and transmitted to the second transmission line connected to the receiving antenna. The terahertz wave interacts with the received light at the receiving antenna chip to generate a current signal.

[0037] The terahertz signal is transmitted to the chip to be tested via the radio frequency probe, and a return detection echo signal is generated from the chip to be tested. The echo signal interacts with the received light again at the receiving antenna to generate an electrical signal for detection;

[0038] Compare the detection echo signal of the chip to be detected with the standard echo signal of the standard chip sample, and judge whether the chip to be detected is faulty, the fault type and the fault location based on the comparison result.

[0039] In this technical solution, the current signal generated at the receiving antenna is transmitted along the transmission line to the RF probe. The RF probe contacts the circuit board of the chip to be tested and transmits the terahertz current signal through the probe into the chip. When an impedance mismatch is encountered, an echo signal is returned and then returned to the receiving antenna. By comparing the waveform differences between the echo signals of the standard chip sample and the chip to be tested, it is possible to determine whether the chip to be tested is faulty and the type of fault. At the same time, after obtaining the dielectric constant of the chip material to be tested in the terahertz frequency band, the transmission distance of the terahertz current signal within the medium can also be calculated. This distance can be used to locate the specific location of the defect. This method is suitable for high-precision detection of open circuit and short circuit defects in 2.5D and 3D chip packages.

[0040] Furthermore, the steps of determining whether the chip to be detected is faulty and the type of fault are as follows:

[0041] Acquire reference impedance information of each position of the standard chip sample based on the standard echo signal, and acquire detection impedance information of each position of the chip to be detected based on the detection echo signal;

[0042] Calculating a reflection coefficient based on the reference impedance information and the detection impedance information;

[0043] If the reflection coefficient is 0, the chip to be tested has no fault;

[0044] If the reflection coefficient is 1, the chip to be tested has an open circuit fault;

[0045] If the reflection coefficient is -1, the chip to be detected has a short circuit fault.

[0046] Furthermore, the step of determining the fault location of the chip to be detected is:

[0047] The dielectric constant of the material of the chip to be detected in the terahertz frequency band, the first time when the radio frequency probe contacts the chip to be detected, and the second time when impedance mismatch occurs in the echo signal to be detected are obtained, and the fault location of the chip to be detected is calculated based on the dielectric constant, the first time, and the second time.

[0048] Compared with the prior art, the present invention has the following beneficial technical effects:

[0049] The present invention is based on the terahertz wave coupling transmission from the transmitting end to the receiving end, and generates a current signal for detection at the receiving end, thereby transforming traditional far-field detection into near-field detection. This not only significantly improves the signal-to-noise ratio and transmission efficiency, but also can be applied to higher-frequency terahertz waves, effectively improving the detection accuracy.

[0050] The signal transmission method of the present invention enables the transmitting and receiving antennas to use antenna materials with dimensions of millimeters, and the distance between each transmission line reaches the micrometer level. As a result, the area of ​​the entire signal transmission structure is only millimeters in size, which is much smaller than the transmission structure of tens of centimeters in the existing technology. This effectively ensures effective transmission efficiency and transmission coupling, while significantly reducing the transmission structure and volume of the detection system.

[0051] The present invention provides a coupled transmission section to bring the first and second transmission lines closer together, thereby reducing terahertz wave transmission loss and improving transmission efficiency. At the same time, the uncoupled output section can be set farther from the second transmission line, significantly reducing the crosstalk caused by the terahertz wave on the second transmission line when propagating in the uncoupled transmission section. This simultaneously achieves high terahertz wave transmission efficiency and low crosstalk, which helps further improve detection accuracy.

[0052] The present invention reduces the loss of terahertz waves propagating along the first transmission line by setting the first angle between the transmission section and the connecting section, and the second angle between the connecting section and the uncoupled transmission section to obtuse angles, thereby further improving the transmission efficiency of terahertz waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0054] Figure 1 This is a structural block diagram of a chip circuit defect detection system based on terahertz on-chip spectroscopy provided by an embodiment of the present invention;

[0055] Figure 2 Schematic diagram of the structure of the transmitting end and the receiving end provided by the embodiment of the present invention;

[0056] Figure 3 Schematic diagram of a defect detection system provided by an embodiment of the present invention testing a chip through a radio frequency probe;

[0057] Figure 4 This is a schematic diagram of a configuration of a transmission line at a transmitting end provided by an embodiment of the present invention;

[0058] Figure 5 Schematic diagram of another configuration of a transmission line at a transmitting end provided by an embodiment of the present invention;

[0059] Figure 6 The present invention provides a flow chart of a chip circuit defect detection method based on terahertz on-chip spectroscopy.

[0060] Explanation of the accompanying drawings: 1-laser, 2-splitter, 3-transmitting end, 4-receiving end, 5-RF probe; 31-first transmission line, 311-connecting section, 312-transmission section, 32-transmitting antenna, 33-DC bias source, 34-first photonic bandgap filter, 35-second photonic bandgap filter; 41-second transmission line, 42-receiving antenna, 43-galvanometer, 44-third photonic bandgap filter. DETAILED DESCRIPTION

[0061] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0062] In the description of the present invention, it should be understood that the terms "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present invention.

[0063] like Figure 1 As shown, the present invention proposes a chip circuit defect detection system based on terahertz on-chip spectroscopy, comprising:

[0064] Laser 1, for generating femtosecond laser;

[0065] A beam splitter 2, used for splitting the femtosecond laser into emitted light and received light;

[0066] The transmitting end 3 is used to generate a terahertz wave after the incident light, and the terahertz wave is coupled and transmitted to the receiving end 4;

[0067] A receiving end 4, configured to receive the incident received light and generate an amplified current signal to be measured based on the interaction between the received light and the terahertz wave at a receiving chip end;

[0068] The radio frequency probe 5 is used to transmit the terahertz signal generated by the transmitter 3 to the chip to be detected;

[0069] like Figure 2 As shown, the transmitting end 3 includes a transmitting antenna 32 and two mutually parallel first transmission lines 31 connected to the transmitting antenna 32, and the first transmission line 31 is connected to a DC bias source 33; the receiving end 4 includes a receiving antenna 42 and two mutually parallel second transmission lines 41 connected to the receiving antenna 42, the second transmission line 41 is connected to the RF probe 5, and the second transmission line 41 is also provided with an ammeter 43.

[0070] In some preferred embodiments, the parameters of the femtosecond laser are: wavelength 1560 nm, pulse width 100 fs, repetition frequency 100 MHz, and power 60 mW.

[0071] In some preferred embodiments, the radio frequency probe 5 is a GSG probe.

[0072] In some embodiments, the transmitting antenna 32 and the receiving antenna 42 are made of the same material. In one or more embodiments, the transmitting antenna 32 and the receiving antenna 42 are made of InGaAs or InAlAs superlattice materials. In some preferred embodiments, the receiving antenna 42 has an InP substrate with a thickness of 1 μm to 5 μm and a period of 50 to 150 layers.

[0073] In some preferred embodiments, in order to improve the coupling transmission efficiency of the terahertz wave and reduce the crosstalk between the transmission lines, the distance D3 between the adjacent first transmission lines 31 and the second transmission lines 41 is 5 μm to 20 μm. Preferably, the distance between the first and second transmission lines is 5 μm to 10 μm.

[0074] In one or more embodiments, the distance D1 between the two first transmission lines 31 is 5 μm to 15 μm. Preferably, the distance between the two first transmission lines 31 is 10 μm to 15 μm, and more preferably, it is 10 μm. In one or more embodiments, the distance D2 between the two second transmission lines 41 is 5 μm to 15 μm. Preferably, the distance between the two second transmission lines 41 is 10 μm to 15 μm, and more preferably, it is 10 μm. In some preferred embodiments, the distance between the two first transmission lines 31 is equal to the distance between the two second transmission lines 41.

[0075] In some embodiments, photonic bandgap filters are provided on the first transmission line 31 and the second transmission line 41 .

[0076] In some preferred embodiments, Figure 2As shown, two first transmission lines 31 extend in parallel, one end of each of the two first transmission lines 31 being connected to a first photonic bandgap filter 34 and the other end being connected to a second photonic bandgap filter 35. Furthermore, the two first transmission lines 31 are also connected to a DC bias source 33. Two second transmission lines 41 also extend in parallel, one end of which is grounded and the other end is connected to a current meter 43 via a third photonic bandgap filter 44. The other second transmission line 41 has one end connected to a radio frequency probe 5 and the other end is also connected to the current meter 43 via the third photonic bandgap filter 44.

[0077] This invention transforms traditional far-field detection into near-field detection by coupling terahertz waves transmitted from a transmitter (3) to a receiver (4) to generate a current signal for detection at the receiver. This significantly improves the signal-to-noise ratio and transmission efficiency and is also applicable to higher-frequency terahertz waves, effectively increasing detection accuracy. This transmission structure can be used not only for chip defect detection but also for other new material detection applications.

[0078] On the other hand, Figure 2 As shown, the first transmission line 31 is parallel to the second transmission line 41. The first transmission line 31 includes a coupled transmission section and an uncoupled transmission section. The distance between the coupled transmission section and the second transmission line 41 is less than the distance between the uncoupled transmission section and the second transmission line 41. By providing the coupled transmission section, the distance between the first and second transmission lines can be made closer, reducing the transmission loss of the terahertz wave and improving the transmission efficiency. In one or more embodiments, the transmitting antenna can be set in the coupled transmission section to achieve efficient coupling of the terahertz wave to the second transmission line 41 after it is generated. At the same time, the distance between the uncoupled transmission section on the first transmission line 31 and the second transmission line 41 can be set farther, significantly reducing the crosstalk caused by the terahertz wave on the second transmission line 41 when propagating in the uncoupled transmission section, while achieving high transmission efficiency and low crosstalk of the terahertz wave, which is conducive to further improving the detection accuracy. In one or more embodiments, the distance between the coupled transmission section and the second transmission line 41 can be 5μm~20μm, and the distance between the uncoupled transmission section and the second transmission line 41 can be 15μm~50μm.

[0079] Preferably, the coupled transmission segment includes a transmission segment 312 parallel to the second transmission line 41, and a connecting segment 311 connected between the transmission segment 312 and the uncoupled transmission segment. The transmission segment 312 needs to be parallel to the second transmission line 41, and the distance between the transmission segment 312 and the second transmission line 41 is 5μm~10μm; the coupled transmission segment is located on the side of the receiving antenna 42 away from the radio frequency probe 5; the first angle between the transmission segment 312 and the connecting segment 311, and the second angle between the connecting segment 311 and the uncoupled transmission segment are both obtuse angles. There are many ways to set the connecting segment 311, which can extend along a straight line, a broken line or a curve. The different settings of the connecting segment 311 also affect the final form of the coupled transmission segment. The transmission segment 312 of the coupled transmission segment is mainly used for coupling terahertz waves, and the connecting segment 311 is used to connect the transmission segment 312 and the uncoupled transmission segment.

[0080] In this embodiment, the signal transmission method allows the transmitting and receiving antennas to use antenna materials with a size of millimeters, and the distance between each transmission line reaches the micron level, so that the area of ​​the entire signal transmission structure is only millimeters in size, which is much smaller than the transmission structure of tens of centimeters in the existing technology. It effectively ensures effective transmission efficiency and transmission coupling, and at the same time greatly reduces the transmission structure and volume of the detection system.

[0081] Preferably, if Figure 4 As shown, the first angle and the second angle in the first transmission line 31 are both right angles. This structure can also achieve coupled transmission of terahertz waves, but the loss of right angles is higher than that of obtuse angles.

[0082] Preferably, if Figure 5 As shown, the connecting section of the first transmission line 31 may also be a curve.

[0083] The present invention also provides a chip circuit defect detection method based on terahertz on-chip spectroscopy, such as Figure 6 As shown, the method includes the following steps:

[0084] generating a femtosecond laser, wherein the femtosecond laser is split into an emission light and a reception light;

[0085] The transmitted light enters the transmitting antenna 32 to generate a terahertz wave that is transmitted along the first transmission line 31. The terahertz wave is coupled and transmitted to the second transmission line 41 connected to the receiving antenna 42. The terahertz wave and the received light generate a current signal at the receiving antenna 42.

[0086] The current signal is transmitted to the chip to be tested via the radio frequency probe 5, and an echo signal is returned for detection;

[0087] Compare the detection echo signal of the chip to be detected with the standard echo signal of the standard chip sample, and determine whether the chip to be detected is faulty, the fault type, and the fault location based on the comparison result.

[0088] In this embodiment, if Figure 3 As shown, after the transmitted light is focused and incident on the transmitting antenna 32, the generated terahertz wave is transmitted to the second transmission line 41 in the bent coupling transmission section. After the receiving light is focused and incident and the terahertz wave is transmitted at the receiving antenna 42, a current signal is generated at the receiving antenna 42. The terahertz signal is transmitted along the transmission line to the radio frequency probe 5. The radio frequency probe 5 contacts the circuit board of the chip to be tested and transmits the terahertz current signal into the chip through the probe. When an impedance mismatch condition is encountered, the signal is returned and then returned to the receiving antenna 42. By comparing the waveform difference of the echo signal of the standard chip sample and the chip to be tested, it can be determined whether the chip to be tested is faulty and the type of fault. At the same time, after obtaining the dielectric constant of the material of the chip to be tested in the terahertz frequency band, the transmission distance of the terahertz current signal inside the medium can also be calculated. This distance can be used to locate the specific location of the defect.

[0089] The steps of determining whether the chip to be tested is faulty and the type of fault are as follows:

[0090] Acquire reference impedance information of each position of the standard chip sample based on the standard echo signal, and acquire detection impedance information of each position of the chip to be detected based on the detection echo signal;

[0091] Calculating a reflection coefficient based on the reference impedance information and the detection impedance information;

[0092] If the reflection coefficient is 0, the chip to be tested has no fault;

[0093] If the reflection coefficient is 1, the chip to be tested has an open circuit fault;

[0094] If the reflection coefficient is -1, the chip to be detected has a short circuit fault.

[0095] In this embodiment, the reference impedance information based on the standard chip sample is set as Z Ref , and the detection impedance information of the chip to be detected is Z L , the reflection coefficient ρ can be calculated as follows:

[0096] ;

[0097] Based on the calculation results of the reflection coefficient, it is determined whether the chip to be tested is faulty and the type of fault. If the reflection coefficient is 0, it indicates that there is no defect inside the circuit of the chip to be tested and the impedances are matched at all locations; if the reflection coefficient is 1, it indicates that an open circuit defect occurs inside the circuit, and the detected detection echo signal waveform is positive at this time; if the reflection coefficient is -1, it indicates that a short circuit defect occurs inside the circuit, and the detected detection echo signal waveform is negative at this time.

[0098] The step of determining the fault location of the chip to be detected is as follows:

[0099] The dielectric constant of the material of the chip to be detected in the terahertz frequency band, the first time when the radio frequency probe contacts the chip to be detected, and the second time when impedance mismatch occurs in the echo signal to be detected are obtained, and the fault location of the chip to be detected is calculated based on the dielectric constant, the first time, and the second time.

[0100] In this embodiment, when the circuit is judged to have failed based on the reflection coefficient, the dielectric constant of the material of the chip to be tested in the terahertz frequency band can be obtained, and the flight distance of the terahertz current signal inside the medium can be calculated based on the dielectric constant, the first time, and the second time. This distance is the distance between the contact point between the RF probe 5 and the chip to be tested and the position of the short circuit or open circuit defect, and the calculation method is:

[0101] ;

[0102] Where c is the speed of light, t0 is the first time, t1 is the second time, is the dielectric constant.

[0103] The terms "first," "second," and so on (e.g., first transmission line, second transmission line, etc.) used in this disclosure are used solely to distinguish between corresponding components for clarity of description and are not intended to limit any order or emphasize importance. Furthermore, the term "connected" used in this disclosure, unless otherwise specified, may refer to a direct connection or an indirect connection via other components.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A chip circuit defect detection system based on terahertz on-chip spectroscopy, characterized in that: The system comprises: A laser (1) for generating femtosecond laser light; A beam splitter (2) for splitting the femtosecond laser into emitted light and received light; A transmitting end (3) is used to generate a terahertz wave after the emission light is incident, and the terahertz wave is coupled and transmitted to a receiving end (4); A receiving end (4), configured to receive the incident light and generate a current signal based on the received light and the terahertz wave; A radio frequency probe (5) is used to transmit the terahertz signal generated by the transmitting end (3) to the chip to be detected; The transmitting end (3) includes a transmitting antenna (32) and two mutually parallel first transmission lines (31) connected to the transmitting antenna (32), and the first transmission lines (31) are connected to a DC bias source (33); the receiving end (4) includes a receiving antenna (42) and two mutually parallel second transmission lines (41) connected to the receiving antenna (42), and the second transmission lines (41) are connected to the radio frequency probe (5), and a weak signal amplifying ammeter (43) is also provided on the second transmission line (41); The first transmission line (31) is parallel to the second transmission line (41), the first transmission line (31) comprises a coupled transmission section and an uncoupled transmission section, and the distance between the coupled transmission section and the second transmission line (41) is smaller than the distance between the uncoupled transmission section and the second transmission line (41).

2. The chip circuit defect detection system based on terahertz on-chip spectroscopy according to claim 1, characterized in that: The coupled transmission section comprises a transmission section (312) parallel to the second transmission line (41) and a connection section (311) connected between the transmission section (312) and the uncoupled transmission section, and the distance between the transmission section (312) and the second transmission line (41) is 5 μm to 10 μm.

3. The chip circuit defect detection system based on terahertz on-chip spectroscopy according to claim 2, characterized in that: The first angle between the transmission section (312) and the connecting section (311) and the second angle between the connecting section (311) and the non-coupling transmission section are both obtuse angles.

4. The chip circuit defect detection system based on terahertz on-chip spectroscopy according to claim 1, characterized in that: The coupling transmission section is located on a side of the receiving antenna (42) away from the radio frequency probe (5).

5. The chip circuit defect detection system based on terahertz on-chip spectroscopy according to any one of claims 1 to 4, characterized in that: Photonic bandgap filters are provided on the first transmission line (31) and the second transmission line (41).

6. A chip circuit defect detection method based on terahertz on-chip spectroscopy, characterized in that: The method comprises the following steps: generating a femtosecond laser, wherein the femtosecond laser is split into an emission light and a reception light; The emitted light enters the transmitting antenna (32) to generate a terahertz wave that is transmitted along the first transmission line (31), the terahertz wave is coupled and transmitted to the second transmission line (41) connected to the receiving antenna (42), and the terahertz wave and the received light generate a current signal at the receiving antenna (42); The terahertz wave generated by the transmitting end is transmitted to the chip to be detected via the radio frequency probe (5), and the echo signal is returned for detection. The echo signal interacts with the received light again at the receiving antenna (42) to generate an electrical signal for detection; Compare the detection echo signal of the chip to be detected with the standard echo signal of the standard chip sample, and determine whether the chip to be detected is faulty, the fault type and the fault location based on the comparison result.

7. The chip circuit defect detection method based on terahertz on-chip spectroscopy according to claim 6, characterized in that: The steps of determining whether the chip to be tested is faulty and the fault type are as follows: Acquire reference impedance information of each position of the standard chip sample based on the standard echo signal, and acquire detection impedance information of each position of the chip to be detected based on the detection echo signal; Calculating a reflection coefficient based on the reference impedance information and the detection impedance information; If the reflection coefficient is 0, the chip to be tested has no fault; If the reflection coefficient is 1, the chip to be tested has an open circuit fault; If the reflection coefficient is -1, the chip to be detected has a short circuit fault.

8. The chip circuit defect detection method based on terahertz on-chip spectroscopy according to claim 7, characterized in that: The steps of determining the fault location of the chip to be detected are: The dielectric constant of the material of the chip to be detected in the terahertz frequency band, the first time when the radio frequency probe (5) contacts the chip to be detected, and the second time when impedance mismatch occurs in the echo signal to be detected are obtained, and the fault position of the chip to be detected is calculated based on the dielectric constant, the first time, and the second time.

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