Detection system and method based on terahertz pulse on-chip radiation detection

Abstract

The invention provides a detection system and method based on terahertz pulse on-chip radiation detection. The detection system and method can be applied to the technical field of terahertz nondestructive detection. The detection system comprises a terahertz pulse radiation unit, a pulse regulation and isolation unit and a terahertz pulse detection unit which are integrated on the same chip, the terahertz pulse radiation unit is used for radiating terahertz detection pulses under the action of the first femtosecond laser pulses; the pulse regulation and isolation unit is used for regulating the terahertz detection pulse input from the first port to be output through the third port and regulating the terahertz reflection pulse input from the third port to be output through the second port; and the terahertz pulse detection unit is connected with the second port and is used for detecting the terahertz reflected pulse to obtain a current signal, so that fault defect detection of the detected sample is realized based on the current signal. According to the detection system, damage to the integrated circuit structure in the detection process is avoided, and the problem of poor fault defect detection accuracy is solved.

Description

Technical Field

[0001] The present application relates to the technical field of terahertz nondestructive testing, and in particular to a detection system and method based on terahertz pulse on-chip radiation detection. Background Art

[0002] With the development of integrated circuit stacking technology, its production process and technology are becoming more and more complicated. In the production process of integrated circuits, due to the complexity of various process flows, slight changes in materials, environment and other factors may cause faults and defects in the internal wires of the integrated circuits. Therefore, it is necessary to detect the fault defect type of the integrated circuit and determine its location.

[0003] However, existing detection technologies have various deficiencies, including the inability to locate the fault defect position, damage to the integrated circuit structure, difficulty in distinguishing the complex packaging and high-density routing of the integrated circuit, etc., resulting in poor accuracy in fault defect detection. Summary of the invention

[0004] In view of the above problems, the present application provides a detection system and method based on terahertz pulse on-chip radiation detection.

[0005] According to a first aspect of the present application, a detection system based on terahertz pulse on-chip radiation detection is provided, which is applied to fault defect detection of integrated circuits or packaged chips. The detection system comprises: a terahertz pulse radiation unit, a pulse control and isolation unit and a terahertz pulse detection unit integrated on the same chip; the terahertz pulse radiation unit is used to radiate terahertz detection pulses under the action of a first femtosecond laser pulse; the pulse control and isolation unit is configured as a planar transmission waveguide structure, comprising a first port, a second port and a third port, for controlling the terahertz detection pulse input from the first port. The terahertz detection pulse is measured, so that the above-mentioned terahertz detection pulse is output through the above-mentioned third port, and the terahertz reflection pulse input from the above-mentioned third port is adjusted, so that the above-mentioned terahertz reflection pulse is output through the above-mentioned second port, wherein the above-mentioned terahertz reflection pulse is a pulse transmitted by the above-mentioned terahertz detection pulse to the sample under test and reflected back from the above-mentioned sample under test; the above-mentioned terahertz pulse detection unit is connected to the above-mentioned second port, and is used for detecting the above-mentioned terahertz reflection pulse under the action of the second femtosecond laser pulse to obtain a current signal, so as to realize fault defect detection of the above-mentioned sample under test based on the above-mentioned current signal.

[0006] According to an embodiment of the present application, the detection system further includes a pulse coupling unit, which includes an on-chip microstrip line and a coaxial waveguide, wherein the first end of the on-chip microstrip line of the pulse coupling unit is connected to the third port of the pulse control and isolation unit, and the second end of the on-chip microstrip line of the pulse coupling unit is connected to the coaxial waveguide; the on-chip microstrip line of the pulse coupling unit is used to transmit the terahertz detection pulse and couple the terahertz detection pulse into the coaxial waveguide.

[0007] According to an embodiment of the present application, the pulse control and isolation unit is provided with an on-chip microstrip line and a dielectric substrate, and the on-chip microstrip line of the pulse control and isolation unit has the first port, the second port and the third port, which are used to achieve isolation of the terahertz detection pulse and the terahertz reflected pulse.

[0008] According to an embodiment of the present application, the detection system further includes a detection unit, which includes a probe connected to the coaxial waveguide, and the probe is used to transmit the terahertz detection pulse to the sample under test, and transmit the terahertz reflection pulse reflected from the sample under test to the coaxial waveguide.

[0009] According to an embodiment of the present application, the above-mentioned detection unit also includes a sample stage and a moving platform, and the above-mentioned probe transmits the above-mentioned terahertz detection pulse and the above-mentioned terahertz reflection pulse through contact coupling; the above-mentioned sample stage is located on the above-mentioned moving platform and is used to carry the above-mentioned sample to be tested; the above-mentioned moving platform is used to adjust the position of the above-mentioned sample to be tested so that the above-mentioned sample to be tested contacts the above-mentioned probe.

[0010] According to an embodiment of the present application, the above-mentioned detection system also includes a processing and display unit, which includes a processing module, a microscope and a display; the above-mentioned processing module is connected to the above-mentioned terahertz pulse detection unit, and is used to process the above-mentioned current signal to determine the fault defect of the above-mentioned sample under test; the above-mentioned microscope is used to observe the degree of contact between the above-mentioned sample under test and the above-mentioned probe; the above-mentioned display is used to display the position of the above-mentioned probe observed through the above-mentioned microscope; the above-mentioned processing module is also used to control the moving direction and distance of the above-mentioned mobile platform and the magnification of the above-mentioned microscope.

[0011] According to an embodiment of the present application, the above-mentioned terahertz pulse radiation unit and the above-mentioned terahertz pulse detection unit are provided with an on-chip KBA structure, at least two metal electrodes, a dielectric substrate and an on-chip microstrip line. The above-mentioned metal electrode, the above-mentioned on-chip KBA structure and the above-mentioned on-chip microstrip line are located in the upper layer of the above-mentioned dielectric substrate, the above-mentioned metal electrode is located on both sides of the above-mentioned on-chip microstrip line, and the area between the above-mentioned metal electrodes is the irradiation area in the above-mentioned on-chip KBA structure; the metal electrode in the above-mentioned terahertz pulse radiation unit is connected to a DC voltage source, and the metal electrode in the above-mentioned terahertz pulse detection unit is connected to an ammeter.

[0012] According to an embodiment of the present application, the first femtosecond laser pulse irradiates the irradiation area in the terahertz pulse radiation unit to generate photogenerated carriers; the photogenerated carriers radiate the terahertz detection pulse under the action of the bias voltage of the metal electrode in the terahertz pulse radiation unit; the terahertz detection pulse is transmitted along the on-chip microstrip line to the first port of the pulse control and isolation unit.

[0013] According to an embodiment of the present application, the second femtosecond laser pulse irradiates the irradiation area in the terahertz pulse detection unit to generate photogenerated carriers; when the terahertz reflected pulse is transmitted along the on-chip microstrip line to the irradiation area in the terahertz pulse detection unit, the photogenerated carriers move in a direction under the action of the terahertz time-domain electric field to form the current signal; wherein the ammeter is used to measure the current value of the current signal.

[0014] The second aspect of the present application provides a detection method based on terahertz pulse on-chip radiation detection, comprising: utilizing a terahertz pulse radiation unit to radiate a terahertz detection pulse under the action of a first femtosecond laser pulse; utilizing a pulse control and isolation unit to control the terahertz detection pulse input from the first port so that the terahertz detection pulse is output through the third port, and controlling the terahertz reflection pulse input from the third port so that the terahertz reflection pulse is output through the second port, wherein the terahertz reflection pulse is a pulse transmitted from the terahertz detection pulse to the sample under test and reflected back from the sample under test; the pulse control and isolation unit is configured as a planar transmission waveguide structure and comprises the first port, the second port and the third port; utilizing a terahertz pulse detection unit to detect the terahertz reflection pulse under the action of a second femtosecond laser pulse to obtain a current signal, so as to realize fault defect detection of the sample under test based on the current signal; wherein the terahertz pulse detection unit is connected to the second port.

[0015] According to the detection system and method based on on-chip terahertz pulse radiation detection provided by the present application, in the detection system based on on-chip terahertz pulse radiation detection, the terahertz pulse radiation unit, the pulse regulation and isolation unit, and the terahertz pulse detection unit are integrated on the same chip, enabling terahertz pulse radiation, transmission, and detection to be carried out on the chip, reducing spatial transmission loss, decreasing the absorption of moisture in free space, weakening the influence of environmental noise, and enhancing system stability. On this basis, based on terahertz detection pulses and terahertz reflection pulses, the detection and positioning of the types of faults and defects in integrated circuits or packaged chips as the samples to be measured are realized. Description of the Drawings

[0016] Figure 1 Shows a schematic diagram of the detection system based on on-chip terahertz pulse radiation detection according to an embodiment of the present application;

[0017] Figure 2 Shows a schematic diagram of generating terahertz detection pulses and detecting terahertz reflection pulses according to an embodiment of the present application;

[0018] Figure 3 Shows a schematic diagram of the pulse regulation and isolation unit according to an embodiment of the present application;

[0019] Figure 4 Shows a schematic diagram of the pulse coupling unit according to an embodiment of the present application;

[0020] Figure 5 Shows a schematic diagram of the pulse coupling unit according to another embodiment of the present application;

[0021] Figure 6 Shows a schematic diagram of the on-chip structure in the detection system according to an embodiment of the present application;

[0022] Figure 7 Shows a schematic diagram of the detection unit according to an embodiment of the present application;

[0023] Figure 8 Shows a schematic diagram of the terahertz pulse radiation unit according to an embodiment of the present application;

[0024] Figure 9 Shows a schematic diagram of the terahertz pulse detection unit according to an embodiment of the present application;

[0025] Figure 10 Shows a schematic diagram of the processing module in the detection system according to an embodiment of the present application;

[0026] Figure 11 Shows a schematic diagram of the processing module according to an embodiment of the present application;

[0027] Figure 12A schematic diagram showing the correlation between the reflection coefficient and the type of fault defect according to an embodiment of the present application;

[0028] Figure 13 A flowchart showing a detection method based on terahertz pulse on-chip radiation detection according to an embodiment of the present application. Detailed implementation manners

[0029] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present application. In the following detailed description, for the sake of explanation, many specific details are set forth in order to provide a comprehensive understanding of the embodiments of the present application. However, obviously, one or more embodiments can also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present application.

[0030] The terms used herein are merely for describing specific embodiments and are not intended to limit the present application. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0031] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0032] In the case of using expressions such as "at least one of A, B, and C", generally, it should be interpreted according to the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0033] In the process of implementing the present application, it is found that with the continuous improvement of various new infrastructures such as the artificial intelligence industry, it is difficult for integrated circuits to adapt to future technological development by simply reducing device size and increasing the area of a single-layer chip. However, the use of wafer-level multi-layer stacking technology can break through the performance limitations of single-layer integrated circuits and well meet the new requirements for integrated circuits in the future.

[0034] However, with the development of integrated circuit stacking technology, slight variations in factors such as materials and environment during the production process may lead to faults and defects in internal wires of integrated circuits. Currently, all common detection technologies have various deficiencies. Therefore, a diagnosis with high resolution and the ability to accurately locate faults in the internal wires of packaged integrated circuits is needed.

[0035] The principle of time domain reflectometry is to inject a pulsed signal into the device under test. The pulsed signal will propagate along the internal wires of the device under test. When encountering an impedance change, part of the pulsed signal will be reflected back to the transmitting end. Thus, based on the time difference between the transmitted pulsed signal and the reflected pulsed signal, as well as the propagation speed of the pulse, the accurate position of the defect point in the integrated circuit can be calculated. Its detection accuracy is mainly determined by the rise time and jitter degree of the pulsed signal. The shorter the rise time and the smaller the jitter degree, the higher the detection accuracy.

[0036] The signal jitter of traditional time domain reflectometers is usually greater than 1 ps (Picosecond), the rising edge time is generally greater than 30 ps, and the resolution is only on the order of millimeters. It is difficult to achieve high-resolution positioning of faults and defects in integrated circuits. The pulse width of terahertz is on the order of picoseconds, with the advantages of short rise time and small signal jitter. Applying it to the detection of faults and defects in integrated circuits can achieve high-precision detection of faults and defects.

[0037] Traditional terahertz time domain spectroscopy systems achieve the coupling of terahertz pulses from photoconductive antennas to probes through spatial coupling, but there are defects such as low spatial coupling efficiency, large influence of environmental noise, and weak system stability.

[0038] Therefore, the embodiments of the present application provide a detection system and method based on terahertz pulse on-chip radiation detection, so as to reduce the loss of spatial transmission and coupling, weaken the influence of environmental noise, improve the system stability, and improve the detection accuracy and accuracy of faults and defects while performing non-destructive detection on multi-layer complex packaged chips or integrated circuits.

[0039] Figure 1 Shows a schematic diagram of a detection system based on terahertz pulse on-chip radiation detection according to an embodiment of the present application.

[0040] The detection system based on terahertz pulse on-chip radiation detection can be applied to the detection of faults and defects in integrated circuits or packaged chips, that is, used to detect faults and defects in integrated circuits or packaged chips and locate the fault defect points in integrated circuits or packaged chips.

[0041] Such as Figure 1As shown in the figure, a detection system based on on-chip radiation detection of terahertz pulses may include a terahertz pulse radiation unit 110, a pulse regulation and isolation unit 120, and a terahertz pulse detection unit 130. Among them, the terahertz pulse radiation unit 110, the pulse regulation and isolation unit 120, and the terahertz pulse detection unit 130 are integrated on the same chip.

[0042] The terahertz pulse radiation unit 110 can be used to radiate terahertz detection pulses under the action of a first femtosecond laser pulse. The pulse regulation and isolation unit 120 is set as a planar transmission waveguide structure. The pulse regulation and isolation unit 120 may include a first port, a second port, and a third port. The pulse regulation and isolation unit 120 can be used to regulate the terahertz detection pulses input from the first port to be output through the third port, and to regulate the terahertz reflection pulses input from the third port to be output through the second port.

[0043] Thus, the terahertz detection pulses are input into the pulse regulation and isolation unit 120 through the first port of the pulse regulation and isolation unit 120 and output through the third port for testing the sample to be measured. The terahertz reflection pulses reflected from the sample to be measured are input into the pulse regulation and isolation unit 120 through the third port of the pulse regulation and isolation unit 120 and output through the second port to enter the terahertz pulse detection unit 130.

[0044] Among them, the terahertz reflection pulses are the pulses that the terahertz detection pulses are transmitted to the sample to be measured and reflected back from the sample to be measured; the sample to be measured may include one of the following: integrated circuits, packaged chips.

[0045] The terahertz detection pulses are transmitted in the sample to be measured. When encountering faults and defects, they will be reflected to reflect back terahertz reflection pulses. Among them, the terahertz reflection pulses carry the fault and defect information of the sample to be measured.

[0046] The terahertz pulse detection unit 130 is connected to the second port of the pulse regulation and isolation unit 120 and is used to detect the input terahertz reflection pulses under the action of a second femtosecond laser pulse to obtain current signals, so as to realize the detection of faults and defects of the sample to be measured based on the current signals.

[0047] Among them, the faults and defects of the sample to be measured may include whether there are faults and defects in the sample to be measured, the types of existing faults and defects, and the positions of the fault and defect points.

[0048] Figure 2 The figure shows a schematic diagram of generating terahertz detection pulses and detecting terahertz reflection pulses according to an embodiment of the present application.

[0049] As Figure 2As shown in the figure, the detection system based on terahertz pulse on-chip radiation detection may further include a system control unit 210, a signal trigger 220, a first femtosecond laser 230, and a second femtosecond laser 240.

[0050] The system control unit 210 can be used to control the signal trigger 220. For example, the system control unit 210 can send a trigger signal sending instruction to the signal trigger 220, and the signal trigger 220 can send a first trigger signal and a second trigger signal in response to the trigger signal sending instruction. Among them, the first trigger signal can be sent to the first femtosecond laser 230, and the second trigger signal can be sent to the second femtosecond laser 240. The repetition frequency difference between the first trigger signal and the second trigger signal is ±1 MHz.

[0051] When the first femtosecond laser 230 receives the first trigger signal, it emits a first femtosecond laser pulse. Among them, the central wavelength of the first femtosecond laser pulse can be 800 - 1600 nm, the repetition frequency is 30 - 100 MHz, and the pulse width is 30 - 59 fs.

[0052] The terahertz pulse radiation unit 110, after receiving the first femtosecond laser pulse, will radiate a terahertz detection pulse to be transmitted into the sample under test and reflect a terahertz reflection pulse from the sample under test.

[0053] When the second femtosecond laser 240 receives the second trigger signal, it emits a second femtosecond laser pulse. Among them, the central wavelength of the second femtosecond laser pulse can be 800 - 1600 nm, the repetition frequency is 30 - 100 MHz, and the pulse width is 30 - 59 fs.

[0054] Based on the above content, the system control unit 210 can be used to control the on and off of the signal trigger 220, and adjust the repetition frequencies of the first femtosecond laser pulse and the second femtosecond laser pulse.

[0055] The terahertz pulse detection unit 130 detects the terahertz reflection pulse after receiving the second femtosecond laser pulse and the terahertz reflection pulse.

[0056] For example, the terahertz pulse detection unit 130 receives the second femtosecond laser pulse periodically, but the terahertz pulse detection unit 130 will only detect when it also receives the terahertz reflection pulse.

[0057] According to an embodiment of the present application, in a detection system based on on-chip terahertz pulse radiation detection, a terahertz pulse radiation unit, a pulse regulation and isolation unit, and a terahertz pulse detection unit are integrated on the same chip, enabling terahertz pulse radiation, transmission, and detection to be performed on-chip, reducing spatial transmission loss, reducing water absorption in free space, weakening the influence of environmental noise, and improving system stability. On this basis, based on terahertz detection pulses and terahertz reflection pulses, detection and localization of the types of faults and defects in an integrated circuit or a packaged chip as the sample to be measured are achieved.

[0058] Figure 3 FIG. shows a schematic diagram of a pulse regulation and isolation unit according to an embodiment of the present application.

[0059] As Figure 3 shown, the pulse regulation and isolation unit 120 is a planar transmission waveguide structure. The pulse regulation and isolation unit 120 is provided with an on-chip microstrip line and a dielectric substrate. The specific structure of the on-chip microstrip line in the pulse regulation and isolation unit 120 is as Figure 3 shown, and the on-chip microstrip line is located on the upper layer of the dielectric substrate. Among them, the material of the dielectric substrate includes but is not limited to GaAs (gallium arsenide).

[0060] The on-chip microstrip line of the pulse regulation and isolation unit 120 has a first port (Port1), a second port (Port2), and a third port (Port3) for isolating terahertz detection pulses and terahertz reflection pulses.

[0061] According to an embodiment of the present application, the relationship between the first port, the second port, and the third port is as Figure 3 shown. Specifically, the first port is connected to the second port through an on-chip microstrip line, the second port is connected to the third port through an on-chip microstrip line, and the third port is connected to the first port through an on-chip microstrip line.

[0062] Based on the connection relationship between the first port, the second port, and the third port, a regulation and isolation core area is formed. In this regulation and isolation core area, the terahertz detection pulse input from the first port is regulated and output from the third port, and the terahertz reflection pulse input from the third port is regulated and output from the second port. On this basis, the terahertz detection pulse and the terahertz reflection pulse are isolated.

[0063] According to an embodiment of the present application, the pulse regulation and isolation unit 120 is configured to regulate the forward-transmitted terahertz detection pulse and the backward-transmitted terahertz reflection pulse carrying fault and defect information of an integrated circuit and a packaged chip, isolate the terahertz reflection pulse from the terahertz detection pulse, enable the terahertz reflection pulse to be transmitted to the terahertz pulse detection unit 130, and enable the terahertz detection pulse to be transmitted to the sample to be measured.

[0064] Figure 4 Shows a schematic diagram of a pulse coupling unit according to an embodiment of the present application.

[0065] As Figure 4 shown, the detection system based on terahertz pulse on-chip radiation detection further includes a pulse coupling unit 410.

[0066] In one embodiment, the first port of the pulse regulation and isolation unit 120 is connected to the terahertz pulse radiation unit 110, the second port of the pulse regulation and isolation unit 120 is connected to the terahertz pulse detection unit 130, and the third port of the pulse regulation and isolation unit 120 is connected to the pulse coupling unit 410.

[0067] Figure 5 Shows a schematic diagram of a pulse coupling unit according to another embodiment of the present application.

[0068] As Figure 5 shown, the pulse coupling unit 410 includes an on-chip microstrip line and a coaxial waveguide. The first end (Port4) of the on-chip microstrip line of the pulse coupling unit 410 is connected to the third port of the pulse regulation and isolation unit 120, and the second end (Port5) of the on-chip microstrip line of the pulse coupling unit 410 is connected to the coaxial waveguide; the on-chip microstrip line of the pulse coupling unit 410 is used to transmit terahertz detection pulses and couple the terahertz detection pulses into the coaxial waveguide, so as to transmit the terahertz detection pulses to the sample to be measured through the coaxial waveguide.

[0069] The on-chip microstrip line of the pulse coupling unit 410 is also used to transmit terahertz reflection pulses and input the terahertz reflection pulses into the third port of the pulse regulation and isolation unit 120.

[0070] Among them, the on-chip microstrip line of the pulse coupling unit 410 is located on the upper layer of the dielectric substrate.

[0071] In one embodiment, the coupling of terahertz detection pulses from the on-chip microstrip line to the coaxial waveguide can be realized at the microstrip-coaxial connection part.

[0072] According to an embodiment of the present application, the pulse coupling unit 410 is used to couple terahertz detection pulses from the on-chip microstrip line to the coaxial waveguide, so as to transmit the terahertz detection pulses to the sample to be measured, and transmit the terahertz reflection pulses to the coaxial waveguide to be transmitted to the terahertz pulse detection unit. Since the coupling process of terahertz detection pulses from the on-chip microstrip line to the coaxial waveguide is carried out on the chip, the spatial coupling loss is reduced.

[0073] According to an embodiment of the present application, the detection system based on on-chip terahertz pulse radiation further includes a detection unit. The detection unit may include a probe, one end of the probe is connected to the coaxial waveguide in the pulse coupling unit 410, and the other end of the probe is connected to the sample to be measured. The probe is used to transmit the terahertz detection pulse into the sample to be measured and transmit the terahertz reflection pulse reflected from the sample to be measured to the coaxial waveguide in the pulse coupling unit 410.

[0074] According to an embodiment of the present application, the probe in the detection unit is connected to the sample to be measured and is used to transmit the terahertz detection pulse to the sample to be measured, so that the terahertz detection pulse is transmitted in the sample to be measured and reflected back as a terahertz reflection pulse. The probe is also used to transmit the terahertz reflection pulse to the pulse coupling unit to realize the detection of the faults and defects of the sample to be measured based on the terahertz reflection pulse, so as to timely discover and locate the faults and defects in the sample to be measured.

[0075] Figure 6 The schematic diagram of the on-chip structure in the detection system according to an embodiment of the present application is shown.

[0076] As Figure 6 shown, the terahertz pulse radiation unit 110, the pulse regulation and isolation unit 120, and the terahertz pulse detection unit 130 are integrated on the same chip.

[0077] In Figure 6 it, the on-chip microstrip line part in the pulse coupling unit 410 is integrated on the same chip with the terahertz pulse radiation unit 110, the pulse regulation and isolation unit 120, and the terahertz pulse detection unit 130. In the pulse coupling unit 410, the terahertz detection pulse transmitted by the on-chip microstrip line is coupled to the coaxial waveguide through the coupling point 610 to ensure that the terahertz detection pulse is effectively transmitted to the probe for detecting the sample to be measured.

[0078] Specifically, the coupling point 610 is a coupling transition region from on-chip to off-chip, which couples the terahertz detection pulse transmitted on the on-chip microstrip line to the off-chip coaxial waveguide.

[0079] A first pulse transmission unit may also be provided between the terahertz pulse radiation unit 110 and the pulse regulation and isolation unit 120 for transmitting the terahertz detection pulse to the first port of the pulse regulation and isolation unit 120. A second pulse transmission unit may also be provided between the terahertz pulse detection unit 130 and the pulse regulation and isolation unit 120 for transmitting the terahertz reflection pulse to the terahertz pulse detection unit 130. Both the first pulse transmission unit and the second pulse transmission unit include an on-chip microstrip line and a dielectric substrate, and the on-chip microstrip line is located on the upper layer of the dielectric substrate.

[0080] According to an embodiment of the present application, the detection unit may further include a sample stage and a moving platform.

[0081] In one embodiment, the mobile platform can be a multi-dimensional precision displacement stage, the probe can be a broadband probe, and the probe can be connected to the sample under test in a physical contact manner.

[0082] Figure 7 The schematic diagram of the detection unit according to an embodiment of the present application is shown.

[0083] As Figure 7 shown, the detection unit may further include a sample stage and a multi-dimensional precision displacement stage.

[0084] In one embodiment, the broadband probe can transmit terahertz detection pulses and terahertz reflection pulses through contact coupling; the sample stage, located on the multi-dimensional precision displacement stage, is used to carry the sample under test; the multi-dimensional precision displacement stage is used to adjust the position of the sample under test so that the sample under test contacts the probe.

[0085] Specifically, the mobile platform can adjust the position of the sample under test in multiple dimensions of up, down, left, right, and 360-degree rotation so that the sample under test contacts the probe.

[0086] According to an embodiment of the present application, the position of the sample under test can be modulated through the sample stage and the mobile platform so that the sample under test contacts the probe, in order to ensure that the probe can effectively transmit the terahertz detection pulse into the sample under test and effectively receive the terahertz reflection pulse reflected from the sample under test, thereby facilitating improving the accuracy of detecting faults and defects in the sample under test.

[0087] Figure 8 The schematic diagram of the terahertz pulse radiation unit according to an embodiment of the present application is shown.

[0088] Figure 9 The schematic diagram of the terahertz pulse detection unit according to an embodiment of the present application is shown.

[0089] As Figure 8 and Figure 9 shown, both the terahertz pulse radiation unit 110 and the terahertz pulse detection unit 130 are provided with an on-chip high-Bao line structure, a dielectric substrate, and an on-chip microstrip line.

[0090] According to an embodiment of the present application, the terahertz pulse radiation unit 110 and the terahertz pulse detection unit 130 may further include at least two metal electrodes. The metal electrodes, the on-chip high-Bao line structure, and the on-chip microstrip line are located on the upper layer of the dielectric substrate. The metal electrodes are located on both sides of the on-chip microstrip line, and the area between the metal electrodes is the irradiation area in the on-chip high-Bao line structure.

[0091] In one embodiment, the metal electrode in the terahertz pulse radiation unit 110 is connected to a DC voltage source, and the metal electrode in the terahertz pulse detection unit 130 is connected to an ammeter.

[0092] In one embodiment, the terahertz pulse radiation unit 110 can be a terahertz photoconductive radiation antenna, and its specific structure can be as Figure 8 shown. The terahertz pulse detection unit 130 can be a terahertz photoconductive detection antenna, and its specific structure can be as Figure 9 shown.

[0093] Among them, the on-chip high-bao line structure has the function of suppressing the backward radiation of terahertz pulses.

[0094] According to an embodiment of the present application, the first femtosecond laser pulse can be irradiated to the irradiation area in the terahertz pulse radiation unit 110 to radiate a terahertz detection pulse, and the second femtosecond laser pulse can be irradiated to the irradiation area in the terahertz pulse detection unit 130 to detect the terahertz reflection pulse.

[0095] According to an embodiment of the present application, the first femtosecond laser pulse irradiates the irradiation area in the terahertz pulse radiation unit to generate photo-generated carriers; under the action of the bias voltage of the metal electrode in the terahertz pulse radiation unit, the photo-generated carriers radiate a terahertz detection pulse; the terahertz detection pulse is transmitted along the on-chip microstrip line to the first port of the pulse regulation and isolation unit.

[0096] In Figure 8 it, after the terahertz pulse radiation unit 110 receives the first femtosecond laser pulse, the first femtosecond laser pulse irradiates the irradiation area to generate photo-generated carriers in the irradiation area. The photo-generated carriers move directionally along the on-chip microstrip line under the action of the bias voltage of the metal electrode, and then radiate a terahertz detection pulse outward. In one embodiment, the intensity of the terahertz detection pulse finally radiated by the photo-generated carriers is affected by the bias voltage, that is, by controlling the bias voltage, the signal radiated by the photo-generated carriers is relatively strong. Among them, the system control unit 210 can also be used to control the bias voltage.

[0097] In one embodiment, the frequency band of the terahertz radiation pulse covers 0.1~1 THz, and the pulse width is 2~20 ps.

[0098] According to an embodiment of the present application, when the first femtosecond laser pulse irradiates the irradiation area and under the action of the bias voltage, the terahertz pulse radiation unit can radiate a terahertz detection unit for transmission to the sample to be measured, so as to detect the faults and defects in the sample to be measured.

[0099] According to an embodiment of the present application, a second femtosecond laser pulse irradiates an irradiation region in a terahertz pulse detection unit to generate photo-generated carriers; when the terahertz reflection pulse travels along the on-chip microstrip line to the irradiation region in the terahertz pulse detection unit, the photo-generated carriers move directionally under the action of the terahertz time-domain electric field to form a current signal;

[0100] wherein, an ammeter is used to measure the current value of the current signal.

[0101] In Figure 9 , after the terahertz pulse detection unit 130 receives the second femtosecond laser pulse, the second femtosecond laser pulse irradiates the irradiation region to generate photo-generated carriers in the irradiation region. When the terahertz reflection pulse travels along the on-chip microstrip line to the irradiation region, the photo-generated carriers move directionally under the drive of the terahertz time-domain electric field to form a current.

[0102] Specifically, the magnitude and direction of the current are proportional to the amplitude and direction of the terahertz time-domain electric field. By measuring the current value, the magnitude of the electric field of the terahertz reflection pulse can be extracted, and thus the detection of the terahertz reflection pulse can be realized.

[0103] wherein, the current value of the generated current can be measured by an ammeter.

[0104] According to an embodiment of the present application, when the second femtosecond laser pulse irradiates the irradiation region and the terahertz reflection pulse also travels to the irradiation region, the terahertz pulse detection unit can be used to detect the terahertz reflection pulse to locate the fault defects in the sample to be measured based on the current signal.

[0105] According to an embodiment of the present application, a detection system based on terahertz pulse on-chip radiation detection may further include a processing and display unit, and the processing and display unit may include a processing module, a microscope and a display; the processing module, connected to the terahertz pulse detection unit, is used to process the current signal to determine the fault defects of the sample to be measured; the microscope is used to observe the contact degree between the sample to be measured and the probe; the display is used to display the position of the probe observed through the microscope; the processing module is further used to control the moving direction and distance of the moving platform and the magnification of the microscope.

[0106] Figure 10 Fig. shows a schematic diagram of the processing module in the detection system according to an embodiment of the present application.

[0107] As Figure 10As shown in the figure, the processing module 1020 is connected to the terahertz pulse detection unit 130. The processing module 1020 is used to receive the current signal generated in the terahertz pulse detection unit 130 to process the current signal. The processing module 1020 is also connected to the detection unit 1010 and is used to control the detection unit 1010 when the contact degree between the sample to be measured and the probe is observed to be poor through the microscope and the display. For example, it can control the moving direction and distance of the moving platform.

[0108] The processing module 1020 can also be connected to the microscope and is used to adjust the magnification of the microscope when the contact degree between the sample to be measured and the probe is observed to be unclear through the microscope and the display mirror.

[0109] Specifically, the processing module 1020 can be configured to receive the directional current signal, process and analyze the current signal, and judge whether there are fault defects in the sample to be measured, the types of fault defects existing, and locate the fault defect points based on the results of the processing and analysis.

[0110] In one embodiment, the microscope can be a high-magnification microscope. The microscope can be located directly above the moving platform and can observe the specific position of the probe through the eyepiece to ensure the contact degree between the sample to be measured and the detection.

[0111] The microscope can be connected to the display to display the position of the probe in the display in real time. The display can also be connected to the terahertz pulse detection unit 130 to display the current signal output after the terahertz pulse detection unit 130 processes the terahertz reflection pulse in real time. The display can also be connected to the processing module 1020 to display the location of the fault defects in the sample to be measured.

[0112] In one embodiment, the microscope can also be connected to the system control unit 210, and the system control unit 210 can also be used to control the magnification of the microscope. Among them, the types of fault defects of the sample to be measured can include short circuit, open circuit, wire size jump, wire bend, via failure, electrode crack, etc.

[0113] According to the embodiments of the present application, the processing module is used to process the current signal output by the terahertz pulse detection unit 130 to determine the fault defects of the sample to be measured, realizing the detection and location of the fault defects in the sample to be measured. The microscope and the display are used to observe and display the contact degree between the sample to be measured and the probe to ensure that the terahertz detection pulse is effectively transmitted into the probe.

[0114] Figure 11 The figure shows a schematic diagram of the processing module according to the embodiments of the present application.

[0115] As Figure 11As shown, the processing module 1020 can be a computer host software processing system. Specifically, the processing module 1020 can include 7 sub-modules: a user interface sub-module 1110, a communication and device management sub-module 1120, a calibration and parameter management sub-module 1130, a test management sub-module 1140, a data processing sub-module 1150, a waveform display sub-module 1160, and a storage and auxiliary sub-module 1170.

[0116] The user interface sub-module 1110 can be used for user command interaction and setting graphic display parameters.

[0117] In one embodiment, setting the graphic display parameters can specifically include setting the range of the x-axis and y-axis of the displayed graph, and selecting a specific graphic area for magnification or reduction.

[0118] The communication and device management sub-module 1120 can be used for checking the connection status of devices, setting the network connection status, and detecting system updates. Among them, the device refers to the detection system for terahertz pulse on-chip radiation detection, and the connection status of each unit and module in the detection system is checked.

[0119] The calibration and parameter management sub-module 1130 is used for calibrating the detection system and setting calibration parameters. Among them, the calibration and parameter management sub-module 1130 includes system calibration programs for calibration methods such as two-point calibration and multi-point calibration.

[0120] Specifically, due to the different positions of the probe that may contact the sample to be measured and the influence of laboratory environment, temperature or other various factors, there will also be a certain error in the test. There will be a standard part relative to the sample to be measured before testing the sample to be measured. Based on the standard part, the laboratory environment is normalized to set the parameters involved in the detection system in advance.

[0121] The test management sub-module 1140 includes a system test program and can be used for controlling the start and stop of test tasks, controlling the moving direction and distance of the moving platform, and adjusting the magnification of the microscope.

[0122] The data processing sub-module 1150 can be used for calculating the position of the fault defect point relative to the test point, processing the original data using processing methods such as filtering and noise reduction, and appropriately adjusting and correcting the processing method. Among them, the original data refers to the current signal output by the terahertz pulse detection unit 130; the test point refers to the position where the terahertz detection pulse enters the sample to be measured.

[0123] Figure 12 The figure shows a schematic diagram of the correlation between the reflection coefficient and the fault defect type according to an embodiment of the present application.

[0124] When the measured sample has an open - circuit fault, the terahertz reflection pulse reflected back from the measured sample by the terahertz detection pulse is a positive - peak pulse signal, that is, the terahertz reflection pulse detected by the terahertz pulse detection unit 130 is a positive pulse; when the measured sample has a short - circuit fault, the terahertz reflection pulse reflected back from the measured sample by the terahertz detection pulse is a negative - peak pulse signal, that is, the terahertz reflection pulse detected by the terahertz pulse detection unit 130 is a negative pulse.

[0125] As Figure 12 shown, the fault defects of the measured sample can be evaluated through the reflection coefficient. When there is no fault defect point at the test position in the sample to be measured, the current signal output by the terahertz pulse detection unit 130 is output to the data processing sub - module 1150 in the processing module 1020 to process the current signal, and the obtained reflection coefficient is 0; when there is an open - circuit fault in the sample to be measured, the reflection coefficient is 1; when there is a short - circuit fault in the sample to be measured, the reflection coefficient is - 1.

[0126] Further, the time when the terahertz detection pulse enters the measured sample is , and the time when reflection occurs at the fault defect point is , then the distance length between the wire fault defect point and the test point in the measured sample is , where is the transmission speed of the terahertz reflection pulse on the wire, , is the speed of light, is the equivalent dielectric constant of the measured sample.

[0127] The waveform display sub - module 1160 can be used to display the reference waveform, the real - time test waveform, move or scale the test waveform, display the fault defect type, and identify and display the fault defect point in the layout of the measured sample.

[0128] The storage and auxiliary sub - module 1170 can be used to store the original waveform and data, store the data after data processing, store the data processing methods and processes, file management, storage and export of test results and log data, etc.

[0129] The detection system based on terahertz pulse on - chip radiation detection may further include a buffer unit, which is connected to the processing module 1020. The buffer unit can be used to cache the collected terahertz reflection pulses and the processing results of the processing module 1020.

[0130] Specifically, the buffer unit can be used to save the original data of the terahertz pulses reflected by the terahertz pulse detection unit 130, the fault defect type, the position of the fault defect point, and the image under the microscope.

[0131] Based on the above, the basic principle of non-destructive testing and diagnosis of internal wires in packaged chips or integrated circuits using terahertz pulse time-domain reflectometry is as follows: When the terahertz detection pulse encounters impedance mismatch in the internal wires of the sample under test during transmission, the waveform of the reflected terahertz pulse will change. By comparing and analyzing the amplitude and phase of the reflected terahertz pulse with those of the emitted terahertz detection pulse, information about the size, position, and nature of the impedance mismatch point can be obtained.

[0132] Therefore, a detection system based on terahertz pulse on-chip radiation detection for detecting faults and defects in packaged chips or integrated circuits can utilize the penetrability of terahertz pulses through plastic encapsulation materials and composite materials, as well as the high-resolution localization characteristics of time-domain reflectometry for defects in multi-layer structures, to achieve non-destructive diagnosis and localization of faults and defects in the sample under test, targeting faults and defects such as line width loss, poor contact, and microcracks at the interfaces between internal layers of multi-layer complex packaged chips and multi-layer PCBs.

[0133] Figure 13 The flowchart of a detection method based on terahertz pulse on-chip radiation detection according to an embodiment of the present application is shown.

[0134] As Figure 13 shown, the detection method 1300 includes operations S1310 to S1330.

[0135] According to an embodiment of the present application, the detection method 1300 can be applied to a detection system as shown in Figures 1 - 10 for detecting faults and defects in integrated circuits or packaged chips.

[0136] In operation S1310, a terahertz detection pulse is radiated using a terahertz pulse radiation unit under the action of a first femtosecond laser pulse.

[0137] In one embodiment, the terahertz pulse radiation unit can be as shown in Figure 8 the figure.

[0138] In operation S1320, a terahertz detection pulse input from a first port is regulated using a pulse regulation and isolation unit so that the terahertz detection pulse is output through a third port, and a terahertz reflected pulse input from the third port is regulated so that the terahertz reflected pulse is output through a second port.

[0139] Wherein, the terahertz reflected pulse is the pulse reflected back from the sample under test after the terahertz detection pulse is transmitted to the sample under test; the pulse regulation and isolation unit is set as a planar transmission waveguide structure and can include a first port, a second port, and a third port; the sample under test can include one of the following: an integrated circuit, a packaged chip.

[0140] According to an embodiment of the present application, the pulse regulation and isolation unit may be as shown Figure 3 as follows.

[0141] In operation S1330, the terahertz pulse detection unit is used to detect the terahertz reflected pulse under the action of the second femtosecond laser pulse to obtain a current signal, so as to realize the detection of faults and defects of the sample to be measured based on the current signal.

[0142] Among them, the terahertz pulse detection unit is connected to the second port.

[0143] According to an embodiment of the present application, the terahertz pulse detection unit may be as shown Figure 9 as follows.

[0144] According to an embodiment of the present application, in the detection system based on terahertz pulse on-chip radiation detection, the terahertz pulse radiation unit, the pulse regulation and isolation unit, and the terahertz pulse detection unit are integrated on the same chip, so that terahertz pulse radiation, transmission, and detection are all carried out on the chip, reducing spatial transmission loss, reducing the absorption of moisture in free space, weakening the influence of environmental noise, and improving the system stability. Moreover, through the detection system based on terahertz pulse on-chip radiation detection, non-destructive diagnostic detection and positioning of internal faults (such as short circuits, open circuits, wire size jumps, wire bends, via failures, electrode cracks, etc.) of multi-layer complex packaged chips or integrated circuits can be realized, so that while improving the detection accuracy and accuracy of faults and defects, the sample to be measured will not be damaged.

[0145] Those skilled in the art can understand that the features described in the various embodiments of the present application can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present application. In particular, without departing from the spirit and teachings of the present application, the features described in the various embodiments of the present application can be combined and / or combined in various ways. All such combinations and / or combinations fall within the scope of the present application.

[0146] The above describes the embodiments of the present application. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present application. Although the embodiments are described separately above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Without departing from the scope of the present application, those skilled in the art can make various substitutions and modifications, and all such substitutions and modifications should fall within the scope of the present application.

Claims

1. A detection system based on on-chip radiation detection of terahertz pulses, which is applied to the fault defect detection of integrated circuits or packaged chips, and is characterized in that, The detection system includes: A terahertz pulse radiation unit, a pulse regulation and isolation unit, and a terahertz pulse detection unit integrated on the same chip; The terahertz pulse radiation unit is configured to radiate a terahertz detection pulse under the action of a first femtosecond laser pulse; The pulse regulation and isolation unit is arranged as a planar transmission waveguide structure, including a first port, a second port, and a third port, and is configured to regulate the terahertz detection pulse input from the first port so that the terahertz detection pulse is output through the third port, and to regulate the terahertz reflection pulse input from the third port so that the terahertz reflection pulse is output through the second port, where the terahertz reflection pulse is the pulse that the terahertz detection pulse transmits to the measured sample and reflects back from the measured sample; The terahertz pulse detection unit is connected to the second port and is configured to detect the terahertz reflection pulse under the action of a second femtosecond laser pulse to obtain a current signal, and to realize the fault defect detection of the measured sample based on the current signal.

2. The detection system according to claim 1, characterized in that, The detection system further includes a pulse coupling unit, the pulse coupling unit includes an on-chip microstrip line and a coaxial waveguide, the first end of the on-chip microstrip line of the pulse coupling unit is connected to the third port of the pulse regulation and isolation unit, and the second end of the on-chip microstrip line of the pulse coupling unit is connected to the coaxial waveguide; the on-chip microstrip line of the pulse coupling unit is configured to transmit the terahertz detection pulse and couple the terahertz detection pulse into the coaxial waveguide.

3. The detection system according to claim 1, characterized in that, The pulse regulation and isolation unit is provided with an on-chip microstrip line and a dielectric substrate, and the on-chip microstrip line of the pulse regulation and isolation unit has the first port, the second port, and the third port, and is configured to isolate the terahertz detection pulse and the terahertz reflection pulse.

4. The detection system according to claim 2, characterized in that, The detection system further includes a detection unit, the detection unit includes a probe, the probe is connected to the coaxial waveguide, and the probe is configured to transmit the terahertz detection pulse to the measured sample and transmit the terahertz reflection pulse reflected from the measured sample to the coaxial waveguide.

5. The detection system according to claim 4, characterized in that The detection unit further includes a sample stage and a moving platform, and the probe transmits the terahertz detection pulse and the terahertz reflection pulse in a contact coupling manner; The sample stage is located on the moving platform and is configured to carry the measured sample; The moving platform is configured to adjust the position of the measured sample so that the measured sample contacts the probe.

6. The detection system according to claim 5, wherein, The detection system further includes a processing and display unit, the processing and display unit includes a processing module, a microscope, and a display; The processing module is connected to the terahertz pulse detection unit and is configured to process the current signal to determine the fault defect of the measured sample; The microscope is configured to observe the contact degree between the measured sample and the probe; The display is configured to display the position of the probe observed through the microscope; The processing module is further configured to control the moving direction and distance of the moving platform and the magnification of the microscope.

7. The detection system according to claim 1, characterized in that, The terahertz pulse radiation unit and the terahertz pulse detection unit are provided with an on-chip KPB structure, at least two metal electrodes, a dielectric substrate and an on-chip microstrip line, wherein the metal electrodes, the on-chip KPB structure and the on-chip microstrip line are located on the upper layer of the dielectric substrate, the metal electrodes are located on both sides of the on-chip microstrip line, and the area between the metal electrodes is the irradiation area in the on-chip KPB structure; The metal electrode in the terahertz pulse radiation unit is connected to a direct current voltage source, and the metal electrode in the terahertz pulse detection unit is connected to an ammeter.

8. The detection system according to claim 7, wherein The first femtosecond laser pulse irradiates the irradiation area in the terahertz pulse radiation unit to generate photogenerated carriers; the photogenerated carriers radiate the terahertz detection pulse under the action of the bias voltage of the metal electrode in the terahertz pulse radiation unit; the terahertz detection pulse is transmitted along the on-chip microstrip line to the first port of the pulse control and isolation unit.

9. The detection system according to claim 7, characterized in that, The second femtosecond laser pulse irradiates the irradiation area in the terahertz pulse detection unit to generate photogenerated carriers; when the terahertz reflected pulse is transmitted along the on-chip microstrip line to the irradiation area in the terahertz pulse detection unit, the photogenerated carriers move directionally under the action of the terahertz time-domain electric field to form the current signal; Wherein, the ammeter is used to measure the current value of the current signal.

10. A detection method based on on-chip radiation detection of terahertz pulses, applied to the detection system described in any one of claims 1 to 9, characterized in that, The detection method comprises: Using a terahertz pulse radiation unit, radiating a terahertz detection pulse under the action of a first femtosecond laser pulse; A pulse control and isolation unit is used to control a terahertz detection pulse input from the first port so that the terahertz detection pulse is output through the third port, and a terahertz reflection pulse input from the third port is controlled so that the terahertz reflection pulse is output through the second port, wherein the terahertz reflection pulse is a pulse transmitted from the terahertz detection pulse to the sample under test and reflected back from the sample under test; the pulse control and isolation unit is configured as a planar transmission waveguide structure and includes the first port, the second port and the third port; A terahertz pulse detection unit is used to detect the terahertz reflected pulse under the action of a second femtosecond laser pulse to obtain a current signal, so as to realize fault defect detection of the sample under test based on the current signal; wherein the terahertz pulse detection unit is connected to the second port.

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