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

Abstract

The present application provides a detection system and method based on terahertz pulse on-chip radiation detection, which can be applied to the field of terahertz non-destructive testing technology. The detection system includes: 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 used to control the terahertz detection pulse input from the first port to be output through the third port, and to control the terahertz reflected pulse input from the third port to be output through the second port; the terahertz pulse detection unit is connected to the second port and is used to detect the terahertz reflected pulse to obtain a current signal, so as to realize fault defect detection of the sample under test based on the current signal. The detection system avoids damage to the integrated circuit structure during the detection process and solves the problem of poor accuracy in fault defect detection.

Description

Technical Field

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

[0002] With the advancement of integrated circuit stacking technology, its production processes and techniques are becoming increasingly complex. Due to the complex process flow, even slight variations in materials, environmental factors, and other factors can cause faults and defects in the internal wiring of the IC. Therefore, it is necessary to detect the type of faults and defects in the IC and determine their location.

[0003] However, existing detection technologies have various shortcomings, including the inability to locate the fault defect position, damage to the integrated circuit structure, difficulty in distinguishing the complex packaging and high-density wiring of the integrated circuit, etc., resulting in poor fault defect detection accuracy. 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 the fault defect detection of integrated circuits or packaged chips. The above-mentioned detection system includes: a terahertz pulse radiation unit, a pulse control and isolation unit and a terahertz pulse detection unit integrated on the same chip; the above-mentioned terahertz pulse radiation unit is used to radiate terahertz detection pulses under the action of a first femtosecond laser pulse; the above-mentioned pulse control and isolation unit is configured as a planar transmission waveguide structure, including a first port, a second port and a third port, for controlling the terahertz detection pulse input from the above-mentioned 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 the 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 above-mentioned detection system also includes a pulse coupling unit, which includes an on-chip microstrip line and a coaxial waveguide. The first end of the on-chip microstrip line of the above-mentioned pulse coupling unit is connected to the third port of the above-mentioned pulse control and isolation unit, and the second end of the on-chip microstrip line of the above-mentioned pulse coupling unit is connected to the above-mentioned coaxial waveguide; the on-chip microstrip line of the above-mentioned pulse coupling unit is used to transmit the above-mentioned terahertz detection pulse and couple the above-mentioned terahertz detection pulse into the above-mentioned 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. 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 between the terahertz detection pulse and the terahertz reflected pulse.

[0008] According to an embodiment of the present application, the above-mentioned detection system also includes a detection unit, and the above-mentioned detection unit includes a probe, which is connected to the above-mentioned coaxial waveguide. The above-mentioned probe is used to transmit the above-mentioned terahertz detection pulse to the above-mentioned sample to be tested, and transmit the above-mentioned terahertz reflection pulse reflected from the above-mentioned sample to the above-mentioned 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 electrodes, the above-mentioned on-chip KBA structure and the above-mentioned on-chip microstrip line are located on the upper layer of the above-mentioned dielectric substrate, the above-mentioned metal electrodes are 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 above-mentioned first femtosecond laser pulse irradiates the irradiation area in the above-mentioned terahertz pulse radiation unit to generate photogenerated carriers; the above-mentioned photogenerated carriers radiate the above-mentioned terahertz detection pulse under the action of the bias voltage of the metal electrode in the above-mentioned terahertz pulse radiation unit; the above-mentioned terahertz detection pulse is transmitted along the above-mentioned on-chip microstrip line to the first port of the above-mentioned pulse control and isolation unit.

[0013] According to an embodiment of the present application, the second femtosecond laser pulse irradiates the irradiated 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 irradiated 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 above-mentioned terahertz detection pulse is output through the third port, and controlling the terahertz reflection pulse input from the third port so that the above-mentioned terahertz reflection pulse is output through the second port, wherein the above-mentioned terahertz reflection pulse is a pulse transmitted from the above-mentioned terahertz detection pulse to the sample under test and reflected back from the above-mentioned sample under test; the above-mentioned pulse control and isolation unit is configured as a planar transmission waveguide structure and comprises the above-mentioned first port, the above-mentioned second port and the above-mentioned third port; utilizing a terahertz pulse detection unit to detect the above-mentioned 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 above-mentioned sample under test based on the above-mentioned current signal; wherein the above-mentioned terahertz pulse detection unit is connected to the above-mentioned second port.

[0015] The detection system and method based on terahertz pulse on-chip radiation detection provided in this application integrates the terahertz pulse radiation unit, pulse control and isolation unit, and terahertz pulse detection unit on the same chip. This allows terahertz pulse radiation, transmission, and detection to be performed on-chip, reducing spatial transmission losses, lowering moisture absorption in free space, weakening the impact of environmental noise, and improving system stability. Furthermore, based on terahertz detection pulses and terahertz reflected pulses, the system can detect and locate fault defect types in integrated circuits or packaged chips as test samples. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0017] Figure 2 A schematic diagram of generating a terahertz detection pulse and detecting a terahertz reflected pulse according to an embodiment of the present application is shown;

[0018] Figure 3 A schematic diagram of a pulse control and isolation unit according to an embodiment of the present application is shown;

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

[0020] Figure 5 FIG2 shows a schematic diagram of a pulse coupling unit according to another embodiment of the present application;

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

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

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

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

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

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

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

[0028] Figure 13 A flow chart of a detection method based on terahertz pulse on-chip radiation detection according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[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 exemplary only and are not intended to limit the scope of the present application. In the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present application. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present application.

[0030] The terms used herein are only for describing specific embodiments and are not intended to limit this application. The terms "comprise," "include," etc. used herein indicate the presence of the 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] When expressions such as "at least one of A, B, and C, etc." are used, they should generally be interpreted in accordance with 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 is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0033] During the implementation of this application, we discovered that with the continuous improvement of various new infrastructures such as the artificial intelligence industry, simply improving the performance of integrated circuits by reducing device size and increasing the area of ​​single-layer chips is no longer able to adapt to future technological developments. However, the use of wafer-level multi-layer stacking technology can overcome the performance limitations of single-layer integrated circuits and effectively meet the new requirements for integrated circuits in the future.

[0034] However, with the development of integrated circuit stacking technology, even slight changes in materials, environment, and other factors during the production process can cause internal wiring defects in integrated circuits. Conventional detection technologies currently have various shortcomings. Therefore, high-resolution diagnostics that can accurately locate internal wiring faults in packaged integrated circuits are needed.

[0035] The principle of time-domain reflectometry is to inject a pulse signal into the component under test. The pulse signal propagates along the internal conductors of the component under test. When encountering impedance changes, part of the pulse signal is reflected back to the transmitter. Based on the time difference between the transmitted and reflected pulse signals and the propagation speed of the pulse, the exact location of the defect in the integrated circuit can be calculated. Its detection accuracy is mainly determined by the rise time and jitter of the pulse signal. The shorter the rise time and the lower the jitter, the higher the detection accuracy.

[0036] Traditional time-domain reflectometry typically exhibits signal jitter exceeding 1 picosecond (ps), rise times exceeding 30 ps, ​​and millimeter-level resolution, making it difficult to locate integrated circuit defects with high resolution. However, terahertz pulse widths, measured in picoseconds, offer the advantages of short rise times and minimal signal jitter. Their application in integrated circuit defect detection enables high-precision defect location.

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

[0038] To this end, 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 impact of environmental noise, improve system stability and improve the detection precision and accuracy of fault defects while performing non-destructive testing on multi-layer complex packaged chips or integrated circuits.

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

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

[0041] like Figure 1As shown, the detection system based on terahertz pulse on-chip radiation detection may include a terahertz pulse radiation unit 110, a pulse control and isolation unit 120 and a terahertz pulse detection unit 130, wherein the terahertz pulse radiation unit 110, the pulse control and isolation unit 120 and the terahertz pulse detection unit 130 are integrated on the same chip.

[0042] The terahertz pulse radiating unit 110 can be configured to radiate terahertz detection pulses under the influence of a first femtosecond laser pulse. The pulse control and isolation unit 120 is configured as a planar transmission waveguide structure and can include a first port, a second port, and a third port. The pulse control and isolation unit 120 can be configured to control the terahertz detection pulse input from the first port to be output through the third port, and to control the terahertz reflected pulse input from the third port to be output through the second port.

[0043] Thus, the terahertz detection pulse is input into the pulse modulation and isolation unit 120 through the first port thereof and output through the third port thereof for use in testing the sample under test. The terahertz reflected pulse reflected from the sample under test is input into the pulse modulation and isolation unit 120 through the third port thereof and output through the second port thereof to enter the terahertz pulse detection unit 130.

[0044] The terahertz reflected pulse is a pulse transmitted by the terahertz detection pulse to the sample under test and reflected back from the sample under test; the sample under test may include one of the following: an integrated circuit, a packaged chip.

[0045] The terahertz detection pulse is transmitted in the sample under test, and when it encounters a fault defect, it will be reflected to reflect back a terahertz reflection pulse, wherein the terahertz reflection pulse carries the fault defect information of the sample under test.

[0046] The terahertz pulse detection unit 130 is connected to the second port of the pulse control and isolation unit 120, and is used to detect the input terahertz reflected pulse under the action of the 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.

[0047] The fault defect of the tested sample may include whether the tested sample has a fault defect, the type of the fault defect, and the location of the fault defect point.

[0048] Figure 2 A schematic diagram of generating a terahertz detection pulse and detecting a terahertz reflected pulse according to an embodiment of the present application is shown.

[0049] like Figure 2As shown, 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. 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 domain of the first trigger signal and the second trigger signal differ by ±1 MHz.

[0051] When receiving the first trigger signal, the first femtosecond laser 230 emits a first femtosecond laser pulse, wherein the center wavelength of the first femtosecond laser pulse may be 800-1600 nm, the repetition frequency may be 30-100 MHz, and the pulse width may be 30-59 fs.

[0052] After receiving the first femtosecond laser pulse, the terahertz pulse radiation unit 110 radiates a terahertz detection pulse to be transmitted to the sample under test and reflects a terahertz reflection pulse back from the sample under test.

[0053] Upon receiving the second trigger signal, the second femtosecond laser 240 emits a second femtosecond laser pulse, wherein the center wavelength of the second femtosecond laser pulse may be 800-1600 nm, the repetition frequency may be 30-100 MHz, and the pulse width may be 30-59 fs.

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

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

[0056] For example, the terahertz pulse detection unit 130 may periodically receive the second femtosecond laser pulse, but the terahertz pulse detection unit 130 may perform detection only when it also receives the terahertz reflected pulse.

[0057] According to the embodiments of this application, a detection system based on on-chip terahertz pulse radiation detection integrates the terahertz pulse radiation unit, pulse control and isolation unit, and terahertz pulse detection unit on a single chip. This allows terahertz pulse radiation, transmission, and detection to all be performed on-chip, reducing spatial transmission losses, lowering moisture absorption in free space, weakening the impact of environmental noise, and improving system stability. Furthermore, based on terahertz detection pulses and terahertz reflected pulses, the system can detect and locate fault defects in integrated circuits or packaged chips as test samples.

[0058] Figure 3 A schematic diagram of a pulse control and isolation unit according to an embodiment of the present application is shown.

[0059] like Figure 3 As shown, the pulse control and isolation unit 120 is a planar transmission waveguide structure. The pulse control 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 control and isolation unit 120 is as follows: Figure 3 As shown in FIG, the on-chip microstrip line is located on the upper layer of the dielectric substrate, wherein the material of the dielectric substrate includes but is not limited to GaAs (gallium arsenide).

[0060] The on-chip microstrip line of the pulse control and isolation unit 120 has a first port (Port 1 ), a second port (Port 2 ), and a third port (Port 3 ), which are used to isolate the terahertz detection pulse from the terahertz reflected pulse.

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

[0062] Based on the connection relationship between the first port, the second port, and the third port, a controllable isolation core region is formed. In this controllable isolation core region, the terahertz detection pulse input from the first port is controlled to be output from the third port, and the terahertz reflected pulse input from the third port is controlled to be output from the second port. On this basis, the terahertz detection pulse and the terahertz reflected pulse are isolated.

[0063] According to an embodiment of the present application, the pulse control and isolation unit 120 is configured to control the forward-transmitted terahertz detection pulse and the reverse-transmitted terahertz reflection pulse carrying integrated circuit and packaged chip fault defect information, isolate the terahertz reflection pulse from the terahertz detection pulse, and enable the terahertz reflection pulse to be transmitted to the terahertz pulse detection unit 130, so that the terahertz detection pulse can be transmitted to the sample under test.

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

[0065] like Figure 4 As 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 control and isolation unit 120 is connected to the terahertz pulse radiation unit 110 , the second port of the pulse control and isolation unit 120 is connected to the terahertz pulse detection unit 130 , and the third port of the pulse control and isolation unit 120 is connected to the pulse coupling unit 410 .

[0067] Figure 5 FIG. 4 is a schematic diagram of a pulse coupling unit according to another embodiment of the present application.

[0068] like Figure 5 As shown, the pulse coupling unit 410 includes an on-chip microstrip line and a coaxial waveguide. The first end (Port 4) of the on-chip microstrip line of the pulse coupling unit 410 is connected to the third port of the pulse control and isolation unit 120, and the second end (Port 5) 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 the terahertz detection pulse and couple the terahertz detection pulse into the coaxial waveguide, thereby transmitting the terahertz detection pulse to the sample under test through the coaxial waveguide.

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

[0070] 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 terahertz detection pulse may be coupled from the on-chip microstrip line to the coaxial waveguide at the microstrip-coaxial connection portion.

[0072] According to an embodiment of the present application, pulse coupling unit 410 is used to couple a terahertz detection pulse from an on-chip microstrip line to a coaxial waveguide, thereby transmitting the terahertz detection pulse to the sample under test and transmitting the reflected terahertz pulse to the coaxial waveguide for transmission to the terahertz pulse detection unit. Because the coupling process of the terahertz detection pulse from the on-chip microstrip line to the coaxial waveguide is performed on-chip, spatial coupling losses are reduced.

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

[0074] According to an embodiment of the present application, a probe in a detection unit is connected to a sample under test and is configured to transmit a terahertz detection pulse to the sample, so that the terahertz detection pulse is transmitted through the sample and reflected back as a terahertz reflection pulse. The probe is also configured to transmit the terahertz reflection pulse to a pulse coupling unit, thereby enabling detection of faults and defects in the sample based on the terahertz reflection pulse, thereby enabling timely discovery and location of faults and defects in the sample.

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

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

[0077] exist Figure 6 In the embodiment, the on-chip microstrip line portion of the pulse coupling unit 410 is integrated on the same chip as the terahertz pulse radiation unit 110, the pulse control 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 portion 610, ensuring that the terahertz detection pulse is effectively transmitted to the probe for testing the sample under test.

[0078] Specifically, the coupling point 610 is an on-chip to off-chip coupling transition region, 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 be provided between the terahertz pulse radiation unit 110 and the pulse control and isolation unit 120 to transmit the terahertz detection pulse to the first port of the pulse control and isolation unit 120. A second pulse transmission unit may be provided between the terahertz pulse detection unit 130 and the pulse control and isolation unit 120 to transmit the terahertz reflected 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, with the on-chip microstrip line being 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 moving platform may be a multi-dimensional precision translation stage, the probe may be a broadband probe, and the probe may be connected to the sample to be measured by physical contact.

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

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

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

[0085] Specifically, the mobile platform can adjust the position of the sample to be tested from multiple dimensions including up, down, left, right, and 360-degree rotation, so that the sample to be tested contacts the probe.

[0086] According to an embodiment of the present application, the position of the sample under test can be modulated by the sample stage and the mobile platform so that the sample under test contacts the probe, thereby ensuring that the probe can effectively transmit the terahertz detection pulse to the sample under test and effectively receive the terahertz reflection pulse reflected back from the sample under test, thereby facilitating improving the accuracy of fault defect detection in the sample under test.

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

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

[0089] like Figure 8 and Figure 9 As shown, the terahertz pulse radiation unit 110 and the terahertz pulse detection unit 130 are both provided with an on-chip K-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 K-type 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 serves as the irradiated area of ​​the on-chip K-type 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 may be a terahertz photoconductive radiation antenna, and its specific structure may be as follows: Figure 8 The terahertz pulse detection unit 130 may be a terahertz photoconductive detection antenna, and its specific structure may be as follows: Figure 9 As shown in .

[0093] Among them, the on-chip high-voltage line structure has the function of suppressing the back 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 irradiation unit 110 to irradiate the 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 reflected pulse.

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

[0096] exist Figure 8 In the embodiment, after the terahertz pulse radiation unit 110 receives the first femtosecond laser pulse, the first femtosecond laser pulse is irradiated onto the irradiated area to generate photogenerated carriers in the irradiated area. Under the influence of the bias voltage of the metal electrode, the photogenerated carriers move in a direction along the on-chip microstrip line, and then radiate terahertz detection pulses outward. In one embodiment, the intensity of the terahertz detection pulses ultimately radiated by the photogenerated carriers is affected by the bias voltage. That is, by controlling the bias voltage, the signal radiated by the photogenerated carriers is made stronger. 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 a first femtosecond laser pulse is irradiated to the irradiation area and under the action of a bias voltage, the terahertz pulse radiation unit can irradiate the terahertz detection unit for transmission to the sample under test, thereby detecting fault defects in the sample under test.

[0099] According to an embodiment of the present application, a second femtosecond laser pulse irradiates an irradiation area in a terahertz pulse detection unit to generate photogenerated carriers. When the terahertz reflected pulse is transmitted along an 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, forming a current signal.

[0100] Among them, the ammeter is used to measure the current value of the current signal.

[0101] exist Figure 9 In the terahertz pulse detection unit 130, after receiving the second femtosecond laser pulse, the second femtosecond laser pulse is irradiated onto the irradiated area to generate photogenerated carriers in the irradiated area. When the reflected terahertz pulse is transmitted along the microstrip line to the irradiated area, the photogenerated carriers move in a direction driven by the terahertz time-domain electric field, forming an electric 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 electric field magnitude of the terahertz reflected pulse can be extracted, thereby realizing the detection of the terahertz reflected pulse.

[0103] 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 is irradiated to the irradiated area and the terahertz reflected pulse is also transmitted to the irradiated area, the terahertz pulse detection unit can be used to detect the terahertz reflected pulse to locate the fault defect in the sample under test 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, which may include a processing module, a microscope and a display; the processing module is connected to the terahertz pulse detection unit, and is used to process the current signal to determine the fault defects of the sample under test; the microscope is used to observe the degree of contact between the sample under test and the probe; the display is used to display the position of the probe observed through the microscope; the processing module is also used to control the moving direction and distance of the mobile platform and the magnification of the microscope.

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

[0107] like Figure 10As shown in FIG, processing module 1020 is connected to terahertz pulse detection unit 130. Processing module 1020 is configured to receive and process the current signal generated by terahertz pulse detection unit 130. Processing module 1020 is also connected to detection unit 1010 and is configured to control detection unit 1010, for example, by controlling the direction and distance of movement of the mobile platform, when poor contact between the sample under test and the probe is observed through the microscope and display.

[0108] The processing module 1020 may also be connected to a microscope to adjust the magnification of the microscope when the contact degree between the sample under test and the probe is not clearly observed through the microscope and the display mirror.

[0109] Specifically, the processing module 1020 can be configured to receive a directional current signal, and process and analyze the current signal to determine whether the tested sample has a fault defect, the type of fault defect, and locate the fault defect point based on the results of processing and analysis.

[0110] In one embodiment, the microscope may be a high-magnification microscope that is located directly above the mobile platform and can observe the specific position of the probe through an eyepiece to ensure the contact degree between the sample being tested and the probe.

[0111] The microscope can be connected to a display to display the probe's position in real time. The display can also be connected to the terahertz pulse detection unit 130 to display in real time the current signal output by the terahertz pulse detection unit 130 after processing the terahertz reflected pulse. The display can also be connected to the processing module 1020 to display the location of the fault defect in the sample being tested.

[0112] In one embodiment, the microscope may be connected to a system control unit 210, which may also be used to control the magnification of the microscope. The types of fault defects in the sample under test may include short circuits, open circuits, wire size jumps, wire bends, through-hole failures, electrode cracks, etc.

[0113] According to the embodiments of the present application, a processing module processes the current signal output by the terahertz pulse detection unit 130 to determine the fault defect in the sample under test, thereby enabling the detection and location of the fault defect in the sample under test. A microscope and a display are used to observe and display the contact between the sample under test and the probe to ensure that the terahertz detection pulse is effectively transmitted to the probe.

[0114] Figure 11 A schematic diagram of a processing module according to an embodiment of the present application is shown.

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

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

[0117] In one embodiment, setting the graphic display parameters may specifically include setting the range of the x-axis and the y-axis of the displayed graphic, and selecting a specific graphic area to zoom in or out.

[0118] The communication and device management submodule 1120 can be used to check the connection status of the device, set the network connection status, and detect system updates. The device refers to the detection system for terahertz pulse on-chip radiation detection, and check the connection status of each unit and module in the detection system.

[0119] The calibration and parameter management submodule 1130 is used to calibrate the detection system and set calibration parameters. The calibration and parameter management submodule 1130 includes system calibration procedures for calibration methods such as two-point calibration and multi-point calibration.

[0120] Specifically, due to the varying locations of the sample the probe may contact, as well as the influence of laboratory environment, temperature, and other factors, which can cause certain errors in testing, a standard component relative to the sample is used before testing. Using this standard component, the laboratory environment is normalized, allowing for pre-setting of the parameters involved in the detection system.

[0121] The test management submodule 1140 includes a system test program, which can be used to control the start and stop of test tasks, control the moving direction and distance of the mobile platform, and adjust the magnification of the microscope.

[0122] The data processing submodule 1150 calculates the distance between the fault defect and the test point, processes the raw data using filtering, noise reduction, and other processing methods, and adjusts and corrects the processing method as appropriate. The raw data refers to the current signal output by the terahertz pulse detection unit 130; the test point refers to the location where the terahertz detection pulse enters the sample under test.

[0123] Figure 12 A schematic diagram showing the correlation between the reflection coefficient and the fault defect type according to an embodiment of the present application is shown.

[0124] When an open circuit fault exists in the sample under test, the terahertz reflected pulse reflected from the sample under test by the terahertz detection pulse is a positive peak pulse signal, that is, the terahertz reflected pulse detected by the terahertz pulse detection unit 130 is a positive pulse; when a short circuit fault exists in the sample under test, the terahertz reflected pulse reflected from the sample under test by the terahertz detection pulse is a negative peak pulse signal, that is, the terahertz reflected pulse detected by the terahertz pulse detection unit 130 is a negative pulse.

[0125] like Figure 12 As shown, the reflection coefficient can be used to evaluate the fault defects of the sample under test. If there is no fault defect point at the test location in the sample under test, the current signal output by the terahertz pulse detection unit 130 is output to the data processing submodule 1150 in the processing module 1020 to process the current signal and obtain a reflection coefficient of 0. If there is an open circuit fault in the sample under test, the reflection coefficient is 1; if there is a short circuit fault in the sample under test, the reflection coefficient is -1.

[0126] Furthermore, the time it takes for the terahertz detection pulse to enter the sample is , the time for reflection to occur at the fault defect point is , then the distance between the fault defect point of the wire in the tested sample and the test point is ,in, is the transmission speed of the terahertz reflected pulse on the wire, , is the speed of light, is the equivalent dielectric constant of the sample being tested.

[0127] The waveform display submodule 1160 can be used to display a reference waveform, a real-time test waveform, move or zoom a test waveform, display a fault defect type, and identify and display a fault defect point in a layout of a sample under test.

[0128] The storage and auxiliary submodule 1170 can be used to store original waveforms and data, store processed data, store data processing methods and processes, manage files, store and export test results and log data, etc.

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

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

[0131] Based on the above content, it can be seen that the basic principle of using terahertz pulse time-domain reflection technology for non-destructive testing and diagnosis of internal wires of packaged chips or integrated circuits is: when the terahertz detection pulse encounters impedance mismatch during transmission on the internal wires of the sample under test, the waveform of the reflected terahertz pulse will change. By comparing and analyzing it with the amplitude and phase of the transmitted terahertz detection pulse, the size, position and properties of the impedance mismatch point can be obtained.

[0132] Therefore, the detection system based on terahertz pulse on-chip radiation detection used for packaged chip or integrated circuit fault defect detection can target fault defects such as line width loss, poor contact, and microcracks in the interconnected interface between internal layers of multi-layer complex packaged chips and multi-layer PCBs. By utilizing the penetration of terahertz pulses into plastic packaging materials and composite materials, and the high-resolution positioning characteristics of time domain reflection technology for defects in multi-layer structures, it can achieve non-destructive diagnosis and positioning of fault defects in the tested samples.

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

[0134] like Figure 13 As 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 Figures 1 to 10 The detection system shown in is used for fault defect detection of integrated circuits or packaged chips.

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

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

[0138] In operation S1320, the pulse control and isolation unit is used to control the terahertz detection pulse input from the first port so that the terahertz detection pulse is output through the third port, and to control the terahertz reflection pulse input from the third port so that the terahertz reflection pulse is output through the second port.

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

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

[0141] In operation S1330, a 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 detect fault defects of the sample under test based on the current signal.

[0142] 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 can be as follows Figure 9 shown.

[0144] According to an embodiment of the present application, a detection system based on terahertz pulse on-chip radiation detection integrates the terahertz pulse radiation unit, pulse control and isolation unit, and terahertz pulse detection unit on the same chip, enabling terahertz pulse radiation, transmission, and detection to be performed on-chip. This reduces spatial transmission losses, lowers moisture absorption in free space, weakens the impact of environmental noise, and improves system stability. Furthermore, this detection system based on terahertz pulse on-chip radiation detection can perform non-destructive diagnostic detection and location of internal faults (such as short circuits, open circuits, wire size jumps, wire bends, via failures, and electrode cracks) in multi-layer, complex packaged chips or integrated circuits, improving the precision and accuracy of fault defect detection without causing damage to the sample being tested.

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

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

Claims

1. A detection system based on terahertz pulse on-chip radiation detection, applied to fault defect detection of integrated circuits or packaged chips, characterized in that: 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 a terahertz detection pulse under the action of the first femtosecond laser pulse; The pulse control and isolation unit is configured as a planar transmission waveguide structure, including a first port, a second port, and a third port, and is configured to control a terahertz detection pulse input from the first port so that the terahertz detection pulse is output through the third port, and to control a terahertz reflected pulse input from the third port so that the terahertz reflected pulse is output through the second port, wherein the terahertz reflected pulse is a pulse transmitted by the terahertz detection pulse to the sample under test and reflected back from the sample under test; The terahertz pulse detection unit is connected to the second port and 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 fault defect detection of the sample under test based on the current signal.

2. The detection system according to claim 1, characterized in that The detection system also includes a pulse coupling unit, which 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 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.

3. The detection system according to claim 1, characterized in that The pulse control and isolation unit is provided with an on-chip microstrip line and a dielectric substrate. 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 between the terahertz detection pulse and the terahertz reflected pulse.

4. The detection system according to claim 2, characterized in that The detection system further includes a detection unit, which includes a probe connected to the coaxial waveguide. 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.

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 by contact coupling; The sample stage is located on the mobile platform and is used to carry the sample to be tested; The movable platform is used to adjust the position of the sample to be tested so that the sample to be tested contacts the probe.

6. The detection system according to claim 5, characterized in that: The detection system further comprises a processing and display unit, wherein the processing and display unit comprises a processing module, a microscope and a display; The processing module is connected to the terahertz pulse detection unit and is used to process the current signal to determine the fault defect of the tested sample; The microscope is used to observe the contact degree between the sample to be tested 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.

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 KBA structure, at least two metal electrodes, a dielectric substrate and an on-chip microstrip line, wherein the metal electrodes, the on-chip KBA 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 KBA structure; The metal electrode in the terahertz pulse radiation unit is connected to a DC 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, characterized in that: 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 terahertz pulse on-chip radiation detection, applied to the detection system according to any one of claims 1 to 9, characterized in that: The detection method comprises: Utilizing a terahertz pulse radiation unit, under the action of a first femtosecond laser pulse, radiates a terahertz detection 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 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 detect fault defects 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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