Interface thermal resistance measuring method and device

Abstract

The invention belongs to the related technical field of interface thermal resistance measurement, and discloses an interface thermal resistance measurement method and device, and the method comprises the steps: (1) moving heating light and probe light from one side of a to-be-measured interface to the other side of the to-be-measured interface, and carrying out the frequency domain heat reflection measurement of a to-be-measured sample during the movement, so as to obtain a measurement signal; (2) inputting the initial parameter value and the estimated interface thermal resistance value of the to-be-measured sample into the vertical interface heat transfer model to obtain an analog signal, and comparing the measurement signal with the analog signal based on optimal fitting by taking the minimum deviation between the measurement signal and the analog signal as a target to obtain the interface thermal resistance value of the to-be-measured interface; the vertical interface heat transfer model is obtained by performing integral summation on respective thermal response functions of media, located on the two sides of the interface to be tested, of the sample to be tested and thermal response functions generated by mutual heat transfer of the media on the two sides. According to the invention, even if the interface to be measured is perpendicular to the heating interface, the interface thermal resistance value of the interface to be measured can be accurately fitted.

Description

Technical Field

[0001] The present invention belongs to the technical field related to interface thermal resistance measurement, and more specifically, relates to an interface thermal resistance measurement method and device. Background Art

[0002] The interface thermal resistance of micro-nano devices plays a vital role in the device's heat dissipation performance, stability, efficiency and other aspects of performance. Therefore, it is necessary to accurately measure the interface thermal resistance of micro-nano devices. At present, the common method of measuring the interface thermal resistance of micro-nano devices is to use frequency domain thermoreflectance (FDTR) technology and time domain thermoreflectance (TDTR) technology to perform non-contact heating and detection of micro-nano device samples through lasers, and obtain the interface thermal resistance of micro-nano device samples by fitting the detection signal with the calculated signal of the heat conduction model. Figure 1 As shown, it is a schematic diagram of a multilayer micro-nano device sample, where Layer 1, Layer 2, etc. are different materials, and there is an interface 12 to be measured between the layers. Currently, laser heating and detection are performed at the dotted center position of the heating interface 11 with the z direction as the heating and detection direction.

[0003] Since the thermal conduction models of TDTR and FDTR both rely on the transfer matrix method, which expresses the heat flow transfer process between sample layers by calculating the matrix, it requires that the layers are regular parallel layers. This limits the method to only measure the interface thermal resistance between layers parallel to the sample surface, that is, the heating interface 11 needs to be parallel to the interface 12 to be measured.

[0004] However, for polycrystalline materials, composite materials, heterojunctions, etc., there is a test interface perpendicular to the heating interface, e.g. Figure 2 , two different materials (medium 1 on the left and medium 2 on the right) are separated by the interface 12 to be measured. Since the heating interface 11 is perpendicular to the interface 12 to be measured, the traditional transmission matrix method cannot measure the interface thermal resistance of the interface 12 to be measured. In addition, since the heating effect of the laser can only diffuse to a limited depth, if the position of the interface to be measured exceeds the limited depth, for example Figure 3 Since the position of the interface 12 to be measured exceeds the heat penetration depth, the traditional transfer matrix method cannot measure the interface thermal resistance of the interface 12 to be measured. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides an interface thermal resistance measurement method and device, which aims to solve the problem that the existing transfer matrix method cannot measure the interface thermal resistance of the interface to be measured when the heating interface is perpendicular to the interface to be measured.

[0006] To achieve the above object, according to one aspect of the present invention, a method for measuring interface thermal resistance is provided, the method comprising the following steps:

[0007] (1) moving the heating light and the detection light from one side of the interface to be measured to the other side of the interface to be measured, and performing frequency domain thermal reflection measurement on the sample to be measured to obtain a measurement signal while moving; the interface to be measured intersects the heating interface of the sample to be measured perpendicularly;

[0008] (2) Inputting the initial parameter value and the estimated interface thermal resistance value of the sample to be tested into the vertical interface heat transfer model to obtain a simulation signal, and then based on the best fit, with the goal of minimizing the deviation between the measurement signal and the simulation signal, comparing the measurement signal with the simulation signal to obtain the interface thermal resistance value of the interface to be tested; the vertical interface heat transfer model is obtained by integrating and summing the thermal response functions of the media on both sides of the interface to be tested and the thermal response functions generated by the heat transfer between the media on both sides.

[0009] Furthermore, it is determined whether the deviation between the measurement signal and the simulation signal is less than a preset deviation threshold. If so, the estimated interface thermal resistance value is used as the interface thermal resistance value of the interface to be measured. If not, the estimated interface thermal resistance value is adjusted, and after the adjustment, the process jumps to the step of obtaining the simulation signal.

[0010] Furthermore, the translation stage is controlled to move from one side of the interface to be tested to the other side of the interface to be tested along a direction perpendicular to the interface to be tested on the heating interface of the sample to be tested. During the movement of the translation stage, the heating light and the detection light are used to perform frequency domain thermal reflection measurement on the sample to be tested to obtain a measurement signal.

[0011] Furthermore, after the translation stage moves a preset step each time, the heating light and detection light of multiple preset frequencies are used to perform frequency domain thermal reflection measurement on the sample to be measured, so as to obtain measurement signals corresponding to each position of the translation stage.

[0012] Furthermore, the sample to be tested is divided into two parts by the test interface, and the media of the two parts are medium 1 and medium 2 respectively; the frequency domain thermal reflection signal detected by the detection light is divided into four parts, which are the thermal response of medium 1 itself and medium 2. Indicates the thermal response of medium 2 itself, using It is used to indicate the thermal response of medium 2 heated by interface heat transfer when heating light acts on medium 1. The thermal response of medium 1 heated by heat transfer at the interface when the heating light acts on medium 2 is expressed by express.

[0013] Furthermore, the four thermal response functions are multiplied by the heating light distribution and then by the detection light distribution, and then the four multiplication results are integrated, and finally the four integration results are summed to obtain the vertical interface heat transfer model.

[0014] Further,

[0015]

[0016] Among them, λ 2x ,λ 2y ,λ 2z They represent the thermal conductivity of medium 1 in the X, Y and Z directions respectively, C1 represents the volume heat capacity of medium 1, λ 2x ,λ 2y ,λ 2z They represent the thermal conductivity of medium 2 in the X, Y and Z directions respectively, c2 represents the volume heat capacity of medium 2, G represents the interface thermal conductivity of the interface to be measured, ξ, ζ represent the Fourier variables of X and Z respectively, ω is the frequency, y′ represents the position of the virtual point source itself, and y represents the position of the virtual point source response.

[0017] Furthermore, the mathematical expression of the vertical interface heat transfer model is:

[0018]

[0019] in, and The calculation formulas are formula (6) and formula (7):

[0020]

[0021] In the formula, y0 represents the center position of the heating light, y1 represents the center position of the detection light, and r p represents the radius of the heating light, r s represents the radius of the detection light, represents the light absorption depth of the heating light in medium 1, represents the light absorption depth of the probe light in medium 1, represents the light absorption depth of the heating light in medium 2, represents the light absorption depth of the probe light in medium 2, represents the temperature response function of the heating light in medium 1, It represents the temperature response function of the heating light in medium 2, and H(ω) represents the frequency domain thermal reflection signal, that is, the vertical interface heat transfer model.

[0022] The present invention also provides an interface thermal resistance measurement system, the system comprising a memory and a processor, the memory storing a computer program, and the processor executing the interface thermal resistance measurement method as described above when executing the computer program.

[0023] The present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores machine-executable instructions. When the machine-executable instructions are called and executed by a processor, the machine-executable instructions prompt the processor to implement the interface thermal resistance measurement method as described above.

[0024] In general, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects:

[0025] 1. The present invention can obtain a vertical interface heat transfer model that can accurately characterize the interface thermal resistance of the vertical interface by integrating the thermal response functions of the media on both sides of the interface to be measured and the thermal response function generated by the heat transfer between the media on both sides. Even if the interface to be measured is perpendicular to the heating interface, the interface thermal resistance value of the interface to be measured can be accurately fitted.

[0026] 2. As long as the interface perpendicular to the interface to be measured is selected as the heating interface, the vertical interface heat transfer model of the present application can be used without considering the relationship between the position of the interface to be measured and the heat penetration depth, and the application range is wider.

[0027] 3. Use heating light and detection light of multiple preset frequencies to perform frequency domain thermal reflection measurement on the sample to be tested, and obtain measurement signals corresponding to each position of the translation stage, so as to more accurately fit the interface thermal resistance.

[0028] 4. The frequency domain thermal reflection signal detected by the detection light is not only related to the thermal response of the media on both sides of the interface to be tested, but also related to the thermal response generated by the heat transfer between the media on both sides. Based on this, the frequency domain thermal reflection signal is divided into four parts, which can solve the problem of different media on both sides of the vertical interface division and improve the accuracy of the model. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of a multi-dimensional micro-nano device;

[0030] Figure 2 It is a schematic diagram that the heating interface is perpendicular to the interface to be measured;

[0031] Figure 3 It is a schematic diagram showing that the position of the interface to be measured exceeds the thermal penetration depth;

[0032] Figure 4 It is a flow chart of a method for measuring interface thermal resistance provided by the present invention;

[0033] Figure 5 It is a schematic diagram of the movement of the heating light and the detection light carried by the translation stage on the heating interface of the sample to be tested;

[0034] Figure 6It is a schematic diagram of Green’s function partitioning;

[0035] Figure 7 It is a schematic diagram of the curve of the change of reflected light intensity and the position of the displacement stage;

[0036] Figure 8 It is the curve of phase and stage position change at each preset frequency;

[0037] Fig. 9 It is a perspective view of modeling the uncoated geometric model;

[0038] Fig.10 This is a schematic diagram of mesh division of the uncoated model;

[0039] Fig.11 It is a structural schematic diagram of an interface thermal resistance measuring device provided by the present invention;

[0040] Fig.12 It is a structural schematic diagram of an electronic device provided by the present invention.

[0041] In all the drawings, the same figure numbers are used to represent the same elements or structures, where: 11-heating interface, 12-interface to be measured, 13-heating light, 14-detection light, 501-control module, 502-measurement module, 503-experimental module, 504-comparison module, 601-processing device, 602-ROM, 603-RAM, 604-bus, 605-input / output (I / O) interface, 606-input device, 607-output device, 608-storage device, 609-communication device. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0043] See also Figure 4 The present invention provides a method for measuring interface thermal resistance, which mainly includes the following steps:

[0044] S401, controlling the translation stage to move on the heating interface of the sample to be tested from one side of the interface to be tested to the other side of the interface to be tested along a direction perpendicular to the interface to be tested; the interface to be tested and the heating interface intersect perpendicularly.

[0045] In one embodiment, an interface in the sample to be tested that is perpendicular to the interface to be tested can be selected as the heating interface, and the translation stage can move on the heating interface, and the moving direction is perpendicular to the interface to be tested. Since the heating interface is perpendicular to the interface to be tested, the heating interface can be divided into two parts by the interface to be tested, and the two parts are respectively set at one side position and the other side position.

[0046] like Figure 5 As shown, the sample to be tested is composed of medium one and medium two, and medium one and medium two intersect at the interface to be tested 12. Under the action of the displacement stage, the heating light 13 and the detection light 14 move along the arrow direction on the heating interface 11 from one side position of the interface to be tested 12 (i.e., one part of the medium) to another measuring position (i.e., part of the medium two).

[0047] The step of determining the one side position and the other side position is: controlling a microscope camera to capture an image of the heating interface, and then determining the one side position and the other side position according to the image.

[0048] Taking into account that the method based on image positioning can only locate the approximate positions of one side and the other side, but cannot locate accurately, in order to avoid the need for the translation stage to move multiple times due to inaccurate positioning, in a preferred embodiment, the intersection range of the interface to be measured and the heating interface is determined according to the image; then the translation stage is controlled to move from the leftmost position of the heating interface to the rightmost position on the heating interface along a direction perpendicular to the interface to be measured; during the movement of the translation stage, the heating light and the detection light are used to perform frequency domain thermal reflection measurement on the sample to be measured, the reflected light intensity during the measurement process is collected, and a change curve of the reflected light intensity and the position of the translation stage is generated; and then the position on one side and the position on the other side are determined according to the change curve.

[0049] Since the frequency domain thermal reflection measurement in this embodiment is only used for precise positioning of the interface to be measured, the frequencies of the heating light and the detection light can be kept fixed in the frequency domain thermal reflection measurement, that is, the translation stage moves one step each time to perform frequency domain thermal reflection measurement on the sample to be measured with heating light and detection light of fixed frequency.

[0050] See also Figure 7 The schematic diagram of the curve of the change of the reflected light intensity and the position of the displacement stage is shown in the figure. When the heating light and the detection light move from one side of the interface to be measured to the other side, due to the different reflectivity of the media on both sides of the interface, the reflected light intensity will have a sudden change when passing through the interface. Figure 7 It is manifested as a sudden decrease in the intensity of the reflected light. In this embodiment, the position of the interface to be measured can be determined based on the position of the displacement stage when the intensity of the reflected light suddenly decreases. For example, Figure 7The position of the interface to be measured is approximately 103 micrometers (μm) to 106 micrometers, and then the position on one side and the position on the other side are determined.

[0051] Compared with the image positioning method, the present invention positions the interface to be measured by measuring the curve of the reflected light intensity changing with the position of the displacement stage, and the positioning result is more accurate.

[0052] In order to verify the accuracy of the above curve positioning method, the present invention can extract the phase of the measurement signal after obtaining the measurement signal in the above step S402, and then generate the following Figure 8 The phase and stage position change curves at various preset frequencies are shown. As the heating light and the detection light gradually approach the interface to be measured, the phase delay increases due to the resistance of the interface to be measured to the heat flow. As the heating light and the detection light gradually approach the interface to be measured and then move away from the interface to be measured, the heat flow on the other side of the interface to be measured is transmitted to this side through the interface to be measured, so that the phase delay of the measurement signal decreases. Figure 8 , the position where the phase delay first increases and then decreases is approximately 102.5 microns to 105 microns, which is consistent with the above positioning results.

[0053] S402, during the movement of the translation stage, frequency domain thermal reflection measurement is performed on the sample to be measured using heating light and detection light to obtain a measurement signal.

[0054] Heating light is also called pump light, which can be loaded with a waveform through an electro-optic modulator to periodically heat the surface of the physical hardware material. The surface of the physical hardware material absorbs the heating of the pump light and presents a temperature rise phenomenon, and then the reflectivity of the pump light changes linearly with the temperature rise. The detection light is used to detect the change of the thermal reflectivity of the surface of the physical hardware material, that is, to detect the linear change of the reflectivity of the pump light with the temperature rise.

[0055] For measurement, the translation stage needs to pause when moving on the heating interface so that the heating light and the detection light can be stably used to perform frequency domain thermal reflection measurement on the sample to be measured. Optionally, the translation stage can be moved according to a fixed preset step, and a measurement is performed each time it moves until the translation stage moves from one side to the other side, and the measurement is terminated to obtain all the measurement signals. Here, the measurement signal refers to the frequency domain thermal reflection signal of the heating light, that is, the linear change of the reflectivity of the above-mentioned pump light with the temperature rise. Data acquisition can be performed through a phase-locked amplifier to obtain the measurement signal.

[0056] After each movement of the translation stage by a preset step, frequency domain thermal reflection measurement is performed on the sample to be measured using heating light and detection light of multiple preset frequencies to obtain measurement signals corresponding to each position of the translation stage, wherein the measurement signal corresponding to any position of the translation stage includes measurement signals corresponding to the multiple preset frequencies.

[0057] In one embodiment, in order to fit the interface thermal resistance more accurately, preferably, the displacement stage can be moved by a preset step, and the heating light and the detection light of multiple preset frequencies can be used to perform frequency domain thermal reflection measurement on the sample to be tested. For example, when the displacement stage moves to position 1 (in this embodiment, the displacement stage position is the center position of the heating light and the detection light), the frequency of the heating light and the detection light is adjusted to the preset frequency 1, and the heating light and the detection light at the preset frequency 1 are used to perform frequency domain thermal reflection measurement on the sample to be tested, and a measurement signal 1 is obtained; then, the frequency of the heating light and the detection light is adjusted to the preset frequency 2, and the heating light and the detection light at the preset frequency 2 are used to perform frequency domain thermal reflection measurement on the sample to be tested, and a measurement signal 2 is obtained; finally, the frequency of the heating light and the detection light is adjusted to the preset frequency 3, and the heating light and the detection light at the preset frequency 3 are used to perform frequency domain thermal reflection measurement on the sample to be tested, and a measurement signal 3 is obtained. After the measurement, the displacement stage is controlled to move a preset step to move the displacement stage to position 2, and then the frequencies of the heating light and the detection light are adjusted to the preset frequency 1, and the heating light and the detection light at the preset frequency 1 are used to perform frequency domain thermal reflection measurement on the sample to be measured, and a measurement signal 4 is obtained; then, the frequencies of the heating light and the detection light are adjusted to the preset frequency 2, and the heating light and the detection light at the preset frequency 2 are used to perform frequency domain thermal reflection measurement on the sample to be measured, and a measurement signal 5 is obtained; finally, the frequencies of the heating light and the detection light are adjusted to the preset frequency 3, and the heating light and the detection light at the preset frequency 3 are used to perform frequency domain thermal reflection measurement on the sample to be measured, and a measurement signal 6 is obtained. And so on. Each time the displacement stage is moved, the detection light signal needs to be rebalanced, that is, the intensity of the heating light and the detection light is adjusted to be consistent; the preset step is 0.1 micrometer.

[0058] S403, inputting the initial parameter value and the estimated interface thermal resistance value of the sample to be tested into the vertical interface heat transfer model to obtain a simulation signal; the vertical interface heat transfer model is obtained by integrating and summing the thermal response functions of the media on both sides of the interface to be tested and the thermal response functions generated by the heat transfer between the media on both sides.

[0059] The traditional transfer matrix method is applicable to the scenario where the heating interface is parallel to the interface to be measured, and the heat transfer model involved is a model generated using a layered heat transfer structure. However, for the scenario where the heating interface is perpendicular to the interface to be measured, the layered heat transfer structure no longer holds true, so the traditional transfer matrix method cannot be applied to the scenario where the heating interface is perpendicular to the interface to be measured.

[0060] In this implementation, the steps of acquiring the analog signal are:

[0061] Inputting the initial parameter value and the estimated interface thermal resistance value of the sample to be tested into the vertical interface heat transfer model to obtain the target vertical interface heat transfer model after parameter transfer;

[0062] The graphics processor is called to perform parallel calculation on the target initial vertical interface heat transfer model according to a preset number of integration nodes to obtain the simulation signal.

[0063] Preferably, the integration adopts Gauss-Legendre integration method.

[0064] In one embodiment, for a scenario where the heating interface is perpendicular to the interface to be measured, the two sides of the interface to be measured are different media, such as Figure 5 As shown, the left and right sides of the interface 12 to be tested are medium 1 and medium 2 respectively. In order to solve the problem of the vertical interface dividing the different media on both sides, the frequency domain thermal reflection signal detected by the detection light is not only related to the thermal response of the media on both sides of the interface to be tested, but also related to the thermal response generated by the heat transfer between the media on both sides. The frequency domain thermal reflection signal can be divided into four parts, namely the thermal response of medium 1 itself (with The thermal response of medium 2 itself (expressed by When the heating light acts on medium 1, the thermal response of medium 2 is generated by heat transfer at the interface (expressed by ), and the thermal response of medium 1 to medium 2 through interface heat transfer when the heating light acts on medium 1 (expressed by express).

[0065] Considering the distribution of heating light and interface heat transfer, the above four thermal responses can be expressed as four Green's functions. Figure 6 As shown, this is a schematic diagram of Green's function partitioning.

[0066] When the heating light is incident on the sample to be tested, it will show a Gaussian distribution, such as Figure 6 The heating light distribution is shown on the left. Figure 6 In the example, the heating light is divided by the interface 12 to be tested into the heating light in the medium 1 and the heating light in the medium 2, which directly heat the medium 1 and the medium 2 respectively, and also heat the medium on the other side through the interface, for example, see Figure 6 In the upper right sub-figure, the virtual point source δ(yy′) corresponding to the heating light heats medium 2 and heats medium 1 through interface heat transfer, where y′ represents the position of the virtual point source δ(yy′) itself and y represents the position of the virtual point source response.

[0067] In Green's function, the thermal response of the heating light can be considered as the superposition of the point source response in the space of the heating light distribution, and the above four thermal responses can be obtained based on this, namely: and

[0068] Among them, λ 2x ,λ 2y,λ 2z They represent the thermal conductivity of medium 1 in the X, Y and Z directions respectively, C1 represents the volume heat capacity of medium 1, λ 2x ,λ 2y ,λ 2z They represent the thermal conductivity of medium 2 in the X, Y and Z directions respectively, C2 represents the volume heat capacity of medium 2, G represents the interface thermal conductivity of the interface to be measured, ζ, ξ represent the Fourier variables of X and Z respectively, ω is the frequency, y′ represents the position of the virtual point source itself, and y represents the position of the virtual point source response.

[0069] The vertical interface heat transfer model of the present invention can be obtained by integrating and summing the above four thermal response functions. Specifically, the above four thermal response functions are first multiplied by the heating light distribution and then by the detection light distribution, and then the four product results are integrated, and finally the four integral results are summed to obtain the vertical interface heat transfer model.

[0070] In this embodiment, the calculation formula of the vertical interface heat transfer model is formula (5):

[0071]

[0072] in, and The calculation formulas are formula (6) and formula (7):

[0073]

[0074] In the formula, y0 represents the center position of the heating light, y1 represents the center position of the detection light, and r p represents the radius of the heating light, r s represents the radius of the detection light, represents the light absorption depth of the heating light in medium 1, represents the light absorption depth of the probe light in medium 1, represents the light absorption depth of the heating light in medium 2, represents the light absorption depth of the probe light in medium 2, represents the temperature response function of the heating light in medium 1, It represents the temperature response function of the heating light in medium 2, and H(ω) represents the frequency domain thermal reflection signal, that is, the vertical interface heat transfer model.

[0075] In this embodiment, the initial parameter values ​​and the estimated interface thermal resistance value of the sample to be tested may be input into the vertical interface heat transfer model to obtain a simulation signal.

[0076] The above initial parameter values ​​need to be consistent with the parameter values ​​used when obtaining the measurement signal in step S402.

[0077] Step S403 is further described in detail:

[0078] The vertical interface heat transfer model is a quadruple integral function, so the process of calculating the simulation signal based on the vertical interface heat transfer model will consume a lot of time. In order to improve the calculation speed, optionally, after the initial parameter value and the estimated interface thermal resistance value of the sample to be tested are input into the vertical interface heat transfer model and the target vertical interface heat transfer model after parameter transfer is obtained, the graphics processor GPU can be called to perform parallel calculations on the target initial vertical interface heat transfer model to obtain the simulation signal.

[0079] Since there is a relatively complete function library for GPU parallel computing acceleration in Python, the torchquad function in the pytorch library can be used to implement the GPU parallel computing process.

[0080] Since the torchquad function can support multiple numerical integration methods such as trapezoidal integration method and Gauss-Legendre integration method, and since the node division of Gauss-Legendre integration method is more consistent with the Gaussian distribution of the function, it is suitable for GPU parallel computing. Therefore, optionally, the Gauss-Legendre integration method can be used when integrating the four thermal response functions.

[0081] Optionally, the number of integration nodes when calling the GPU to perform parallel calculations on the target initial vertical interface heat transfer model can be pre-set to 70 per dimension, that is, 70 integration nodes are set for each integral in the quadruple integral.

[0082] For example, for the y-multiple integral, 70 integration nodes are set, and the GPU can calculate the y values ​​at the 70 integration nodes respectively, and then sum the 70 y values ​​as the final integration result of the y-multiple integral.

[0083] It should be noted that the above setting of 70 integration nodes is only an example and is not intended to limit the present invention. If the video memory is sufficient, more integration nodes may be divided as much as possible to reduce errors.

[0084] In this embodiment, an integral cutoff may be set to replace the above integral range of 0 to ∞. Optionally, the integral cutoffs for y, y′, ξ, and ζ may be set to 10×r S , 10×r p , and According to tests, the integral truncation set in this embodiment can achieve better accuracy in the numerical calculation of the frequency domain thermal reflection signal (ie, the analog signal).

[0085] The embodiment of the present invention can calculate the simulation signal more quickly and accurately by calling the GPU and setting a suitable integration method, integration node and integration cutoff, thereby improving the fitting process of the interface thermal resistance value of the interface to be measured.

[0086] S404, determine whether the deviation between the measurement signal and the simulation signal is less than a preset deviation threshold, if so, use the estimated interface thermal resistance value as the interface thermal resistance value of the interface to be measured, if not, adjust the estimated interface thermal resistance value, and jump to step S403 after adjustment.

[0087] In this embodiment, the deviation between the measurement signal and the simulation signal can be calculated. For each position where the translation stage moves, it can include measurement signals at multiple preset frequencies. Similarly, the above-mentioned initial parameter values ​​can be set so that for each simulated translation stage position, it includes simulation signals at multiple preset frequencies. The deviation in this embodiment may refer to the sum of the deviations between the measurement signal and the simulation signal at all preset frequencies corresponding to all translation stage positions.

[0088] For example, for position 1, this embodiment obtains measurement signal 1 and analog signal 1 at preset frequency 1, measurement signal 2 and analog signal 2 at preset frequency 2, and measurement signal 3 and analog signal 3 at preset frequency 3; for position 2, measurement signal 4 and analog signal 4 at preset frequency 1, measurement signal 5 and analog signal 5 at preset frequency 2, and measurement signal 6 and analog signal 6 at preset frequency 3 are obtained, then the deviation of the measurement signal and the analog signal in this embodiment = (measurement signal 1-analog signal 1) + (measurement signal 2-analog signal 2) + (measurement signal 3-analog signal 3) + (measurement signal 4-analog signal 4) + (measurement signal 5-analog signal 5) + (measurement signal 6-analog signal 6).

[0089] Of course, the deviation calculation method provided above is only an example, and other methods may also be used, for example, respectively extracting the phases of the measurement signal and the analog signal and then calculating the root mean square of the phase difference based on the extracted phases as the calculated deviation, or respectively extracting the amplitudes of the measurement signal and the analog signal and then calculating the root mean square of the amplitude difference based on the extracted amplitudes as the calculated deviation, etc. The present invention is not limited thereto.

[0090] If the above calculated deviation is greater than the preset deviation threshold, it means that the measurement signal and the simulation signal cannot fit well, and further means that the estimated interface thermal resistance value is very different from the actual interface thermal resistance value of the interface to be measured. In this case, the estimated interface thermal resistance value can be adjusted. For example, the estimated interface thermal resistance value is adjusted from value 1 to value 2, and then value 2 is input into the vertical interface heat transfer model, the simulation signal is calculated again and the deviation is calculated. If the deviation is less than the preset deviation threshold at this time, value 2 is used as the interface thermal resistance value of the interface to be measured. If the deviation is still greater than the preset deviation threshold at this time, the estimated interface thermal resistance value is adjusted from value 2 to value 3, and is input into the vertical interface heat transfer model again, and so on, until an estimated interface thermal resistance value is obtained that makes the deviation between the measurement signal and the simulation signal less than the preset deviation threshold, and then it is used as the interface thermal resistance value of the interface to be measured.

[0091] Optionally, the process of continuously adjusting the estimated node thermal resistance value and comparing the deviation with a preset deviation threshold may be implemented using a minimum value search function.

[0092] The measurement method provided by the present invention first controls the displacement stage to move from one side of the interface to be measured to the other side along the direction perpendicular to the interface to be measured on the heating interface of the sample to be measured, and in the process of moving, the heating light and the detection light are used to perform frequency domain thermal reflection measurement on the sample to be measured to obtain a measurement signal, and then the initial parameter value and the estimated interface thermal resistance value of the sample to be measured are input into the vertical interface heat transfer model to obtain a simulation signal, and finally the deviation of the measurement signal and the simulation signal is calculated and compared with a preset deviation threshold, if the calculated deviation is greater than or equal to the preset deviation threshold, the estimated interface thermal resistance value is continuously adjusted, and then input into the vertical interface heat transfer model to calculate the simulation signal, until the calculated deviation is less than the preset deviation threshold, and the estimated interface thermal resistance value at this time is used as the interface thermal resistance value of the interface to be measured. The present invention can integrate the thermal response functions of the media on both sides of the interface to be measured and the thermal response functions generated by the mutual heat transfer of the media on both sides, so as to obtain a vertical interface heat transfer model that can accurately characterize the interface thermal resistance of the vertical interface, so that even if the interface to be measured is perpendicular to the heating interface, the interface thermal resistance value of the interface to be measured can be accurately fitted. At the same time, as long as an interface perpendicular to the interface to be measured is selected as the heating interface, the vertical interface heat transfer model of the present invention can be used without considering the relationship between the position of the interface to be measured and the heat penetration depth, and the application range is wider.

[0093] A thermal reflection model can be established by COMSOL software to verify whether the interface thermal resistance value fitted by the present invention is accurate.

[0094] Specifically, a model was established in COMSOL according to specific working conditions, and the temperature response of the sample surface was solved through simulation. The weighted average of the detection light intensity distribution of the temperature response was performed to simulate the reflection signal of the detection light under experimental conditions, and then the phase delay was obtained. By modifying the heating light position, a parametric scan was performed, and the phase and amplitude curves changing with the heating light position were calculated.

[0095] First, set the parameters of the working condition to be investigated in the software. Take the Gaussian light with power of 2mW, frequency of 1MHz, and radius of 1μm to heat the sample surface, and the center position of the heating light moves from 3μm to the left of the interface to be tested to 3μm to the right of the interface as an example. Set variables: power P = 2mW, frequency f = 1MHz, heating light radius r p =1μm, detection light radius r S =1μm, heating light position x0=250, y0=500, heating light distribution expression Flux=2*p0 / pi / rp^2*exp((-2*(y-y0)^2-2*(x-x0)^2) / rp^2).

[0096] Next, a geometric model was constructed by splicing two solid blocks with a length, width and height of 500 μm to simulate semi-infinite heat transfer. The material thermal properties were set to thermal conductivity λ1 = λ2 = 10 W / (m 2 ·K), density is 2500kg / m3, constant pressure heat capacity is 1000J / (kg·K). A cylinder with a radius of 5μm and a height of 2μm is set at the junction of the heating surface and the interface to be measured. Fig. 9 Modeling perspective of the uncoated geometry shown.

[0097] The physical field setting uses the COMSOL solid thermal conductivity module. The initial value is set to room temperature by default; the ideal thermal insulation condition is set on the heating surface; the boundary conditions of the convective heat flux are set on the four sides and the bottom, and the convective heat transfer coefficient h = 10W / (K·m2); the contact thermal resistance is set on the contact surface of the two blocks, the type is thin layer contact thermal resistance, and the interface thermal resistance of the four working conditions is set to 10-20, 10-7, 10-6, 1K·m2·W-1 respectively; the boundary heat source added on the surface of the cylinder is set to harmonic perturbation.

[0098] The meshing of the uncoated model is as follows: Fig.10 As shown in the figure, the heating area is small and the temperature change sampling points are fine, so a more detailed temperature distribution needs to be obtained. Therefore, the cylindrical area is finely meshed, and a free quadrilateral mesh is used to generate a surface mesh with a maximum of 0.1μm and a minimum of 0.005μm on the surface. The entire cylindrical area is meshed by sweeping, and the swept mesh size is set to a maximum of 0.1μm. The remaining part simulates the semi-infinite situation, and the temperature change is small, so the free tetrahedral mesh is used for automatic division.

[0099] Set it to solve the frequency domain disturbance, and set the frequency to f=1MHz, and you can get the temperature distribution and isothermal surface in the cylindrical area.

[0100] In order to simulate the scanning of heating light and detection light in the experiment and obtain the corresponding frequency domain thermal reflection signal curve, it is necessary to change the heating light coordinates so that it scans from -3μm of the interface to 3μm, and calculate the corresponding phase and amplitude curves. The scanning and weighted average process of the detection light intensity distribution are completed by COMSOL Multiphysics 6.1with MATLAB module, which can realize the functions of controlling COMSOL to change parameters, run simulations, process data, etc. through MATLAB program. The present invention uses a program for data extraction, processing and storage of simulation results. The program first constructs a sampling matrix to extract the temperature response of 1000×1000 points uniformly sampled in a square area of ​​20μm×20μm around the center of the heating light. Next, the detection light intensity distribution function is set to multiply the obtained temperature distribution matrix by the detection light intensity function, and then sum to obtain the thermal reflection signal of the point and store it. By cyclically changing the coordinates of the heated photosynthetic detection light, the 3μm area on both sides of the interface is linearly divided into two hundred scanning points. The coordinates of the center position of the heating light are changed successively and the simulation is rerun. The two hundred heating position coordinates are traversed, and the frequency domain temperature response is calculated one by one to simulate the signal of the detection light reflected into the phase-locked amplifier in the experiment.

[0101] By fitting the experimental data obtained by COMSOL simulation with the measurement signal calculated by inputting the interface thermal resistance value of the interface to be measured into the vertical interface heat transfer model, the fitting results are basically consistent, which can verify that the vertical interface heat transfer model provided by the present invention can accurately obtain the interface thermal resistance value of the interface to be measured.

[0102] See also Fig.11 The present invention also provides an interface thermal resistance measuring device, the device comprising:

[0103] The control module 501 is used to control the translation stage to move from one side of the test interface to another side of the test interface along a direction perpendicular to the test interface on the heating interface of the test sample; wherein the test interface is perpendicular to the heating interface;

[0104] The measuring module 502 is used to perform frequency domain thermal reflection measurement of the sample to be measured using the heating light and the detection light during the movement of the translation stage to obtain a measurement signal;

[0105] Experimental module 503, used to input the initial parameter value and the estimated interface thermal resistance value of the sample to be tested into the vertical interface heat transfer model to obtain a simulation signal; wherein the vertical interface heat transfer model is obtained by integrating and summing the thermal response functions of the media on both sides of the interface to be tested and the thermal response functions generated by the heat transfer between the media on both sides;

[0106] The comparison module 504 is used to determine whether the deviation between the measurement signal and the simulation signal is less than a preset deviation threshold. If so, the estimated interface thermal resistance value is used as the interface thermal resistance value of the interface to be measured. If not, the estimated interface thermal resistance value is adjusted. After adjustment, the initial parameter value of the sample to be measured and the estimated interface thermal resistance value are returned and input into the vertical interface heat transfer model.

[0107] When the control module determines the position on one side and the position on the other side, it may specifically be:

[0108] Controlling a microscope camera to capture an image of the heated interface;

[0109] The position of one side and the position of the other side are determined based on the image.

[0110] In a possible implementation, when the control module determines the position of one side and the position of the other side according to the image, specifically:

[0111] Determine the intersection range of the interface to be tested and the heating interface according to the image;

[0112] Controlling the translation stage to move from the leftmost position of the heating interface to the rightmost position on the heating interface along a direction perpendicular to the interface to be measured;

[0113] During the movement of the translation stage, the heating light and the detection light are used to perform frequency domain thermal reflection measurement on the sample to be measured, and the reflected light intensity during the measurement process is collected to generate a curve of the change of the reflected light intensity and the position of the translation stage;

[0114] The position on one side and the position on the other side are determined according to the change curve.

[0115] In a possible implementation, the measurement module uses heating light and detection light to perform frequency domain thermal reflection measurement on the sample to be measured during the process of controlling the movement of the translation stage, and when obtaining the measurement signal, it can be specifically:

[0116] Each time the translation stage moves a preset step, frequency domain thermal reflection measurement is performed on the sample to be measured using heating light and detection light of multiple preset frequencies to obtain measurement signals corresponding to each position of the translation stage, wherein the measurement signal corresponding to any position of the translation stage includes measurement signals corresponding to multiple preset frequencies.

[0117] In a possible implementation, when the above experimental module inputs the initial parameter value and the estimated interface thermal resistance value of the sample to be tested into the vertical interface heat transfer model to obtain the simulation signal, specifically:

[0118] Inputting the initial parameter value and the estimated interface thermal resistance value of the sample to be tested into the vertical interface heat transfer model to obtain the target vertical interface heat transfer model after parameter transfer;

[0119] The graphics processor is called to perform parallel calculation on the target initial vertical interface heat transfer model according to a preset number of integration nodes to obtain a simulation signal.

[0120] See also Fig.12 The present invention also provides an electronic device, which may include but is not limited to fixed terminals such as mobile phones, notebook computers, PDAs (personal digital assistants), PADs (tablet computers), desktop computers, etc. Fig.12 The electronic device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present invention.

[0121] like Fig.12 As shown, the electronic device may include a processing device (such as a central processing unit, a graphics processor, etc.) 601, which can perform various appropriate actions and processes according to a program stored in a read-only memory ROM 602 or a program loaded from a storage device 608 to a random access memory RAM 603, so that the electronic device can implement the interface thermal resistance measurement method provided by any of the above embodiments. When the electronic device is powered on, various programs and data required for the operation of the electronic device are also stored in RAM 603. The processing device 601, ROM 602 and RAM 603 are connected to each other via a bus 604. An input / output (I / O) interface 605 is also connected to the bus 604.

[0122] Typically, the following devices may be connected to the I / O interface 605: an input device 606 including, for example, a touch screen, a touch pad, a keyboard, a mouse, a camera, a microphone, an accelerometer, a gyroscope, etc.; an output device 607 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; a storage device 608 including, for example, a memory card, a hard disk, etc.; and a communication device 609. The communication device 609 may allow the electronic device to communicate with other devices wirelessly or by wire to exchange data.

[0123] An embodiment of the present invention further provides a computer program product including computer-readable instructions. When the computer-readable instructions are executed on an electronic device, the electronic device implements any interface thermal resistance measurement method provided by the embodiment of the present invention.

[0124] A computer-readable storage medium is also provided in an embodiment of the present invention. The storage medium carries one or more computer programs. When the one or more computer programs are executed by an electronic device, the electronic device can implement any interface thermal resistance measurement method provided in an embodiment of the present invention.

[0125] It should also be noted that the device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment. In addition, in the drawings of the device embodiments provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, which may be specifically implemented as one or more communication buses or signal lines.

[0126] Through the description of the above implementation mode, the technicians in the relevant field can clearly understand that the present invention can be implemented by means of software plus necessary general hardware, and of course, it can also be implemented by special hardware including special integrated circuits, special CPUs, special memories, special components, etc. In general, all functions completed by computer programs can be easily implemented by corresponding hardware, and the specific hardware structure used to implement the same function can also be various, such as analog circuits, digital circuits or special circuits. However, for the present invention, software program implementation is a better implementation mode in more cases. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a readable storage medium, such as a computer floppy disk, a U disk, a mobile hard disk, a ROM, a RAM, a magnetic disk or an optical disk, etc., including a number of instructions to enable a computer device (which can be a personal computer, a training device, or a network device, etc.) to execute the methods described in each embodiment of the present invention.

[0127] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments may be implemented in the form of a computer program product.

[0128] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present invention is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website, a computer, a training device, or a data center to another website, a computer, a training device, or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a training device, a data center, etc. that includes one or more available media integrated. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)), etc.

[0129] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for measuring interface thermal resistance, characterized in that: The method comprises the following steps: (1) moving the heating light and the detection light from one side of the interface to be measured to the other side of the interface to be measured, and performing frequency domain thermal reflection measurement on the sample to be measured to obtain a measurement signal while moving; the interface to be measured intersects the heating interface of the sample to be measured perpendicularly; (2) Inputting the initial parameter value and the estimated interface thermal resistance value of the sample to be tested into the vertical interface heat transfer model to obtain a simulation signal, and then based on the best fit, with the minimum deviation angle between the measurement signal and the simulation signal as the goal, comparing the measurement signal with the simulation signal to obtain the interface thermal resistance value of the interface to be tested; the vertical interface heat transfer model is obtained by integrating and summing the thermal response functions of the media on both sides of the sample to be tested located at the interface to be tested and the thermal response functions generated by the heat transfer between the media on both sides.

2. The method for measuring interfacial thermal resistance according to claim 1, wherein: Determine whether the deviation between the measurement signal and the simulation signal is less than a preset deviation threshold. If so, use the estimated interface thermal resistance value as the interface thermal resistance value of the interface to be measured. If not, adjust the estimated interface thermal resistance value and jump to the step of obtaining the simulation signal after adjustment.

3. The method for measuring interfacial thermal resistance according to claim 1, wherein: The displacement stage is controlled to move from one side of the interface to be tested to the other side of the interface to be tested along a direction perpendicular to the interface to be tested. During the movement of the displacement stage, the heating light and the detection light are used to perform frequency domain thermal reflection measurement on the sample to be tested to obtain a measurement signal.

4. The method for measuring interfacial thermal resistance according to claim 1, wherein: After the translation stage moves a preset step, the sample to be measured is subjected to frequency domain thermal reflection measurement using heating light and detection light of multiple preset frequencies to obtain measurement signals corresponding to each position of the translation stage.

5. The method for measuring interfacial thermal resistance according to claim 1, wherein: The sample to be tested is divided into two parts by the test interface, and the media of the two parts are medium 1 and medium 2 respectively; the frequency domain thermal reflection signal detected by the detection light is divided into four parts, which are the thermal response of medium 1 itself, Indicates the thermal response of medium 2 itself, using It is used to indicate the thermal response of medium 2 when heating light acts on medium 1 through interface heat transfer. The thermal response of medium 1 heated by heat transfer at the interface when the heating light acts on medium 2 is expressed by express.

6. The method for measuring interfacial thermal resistance according to claim 5, characterized in that: The four thermal response functions are multiplied by the heating light distribution and then by the detection light distribution, and then the four product results are integrated. Finally, the four integral results are summed to obtain the vertical interface heat transfer model.

7. The method for measuring interfacial thermal resistance according to claim 5, characterized in that: Among them, λ 2x ,λ 2y ,λ 2z They represent the thermal conductivity of medium 1 in the X, Y and Z directions respectively, C1 represents the volume heat capacity of medium 1, λ 2x ,λ 2y ,λ 2z They represent the thermal conductivity of medium 2 in the X, Y and Z directions respectively, C2 represents the volume heat capacity of medium 2, G represents the interface thermal conductivity of the interface to be measured, ξ, ζ represent the Fourier variables of X and Z respectively, ω is the frequency, y′ represents the position of the virtual point source itself, and y represents the position of the virtual point source response.

8. The method for measuring interfacial thermal resistance according to any one of claims 1 to 7, characterized in that: The mathematical expression of the vertical interface heat transfer model is: in, and The calculation formulas are formula (6) and formula (7): In the formula, y0 represents the center position of the heating light, y1 represents the center position of the detection light, and r p represents the radius of the heating light, r s represents the radius of the detection light, represents the light absorption depth of the heating light in medium 1, represents the light absorption depth of the probe light in medium 1, represents the light absorption depth of the heating light in medium 2, represents the light absorption depth of the probe light in medium 2, represents the temperature response function of the heating light in medium 1, It represents the temperature response function of the heating light in medium 2, and H(ω) represents the frequency domain thermal reflection signal, that is, the vertical interface heat transfer model.

9. An interface thermal resistance measurement system, characterized in that: The system includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the interface thermal resistance measurement method according to any one of claims 1 to 8 when executing the computer program.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores machine-executable instructions. When the machine-executable instructions are called and executed by a processor, the machine-executable instructions prompt the processor to implement the interface thermal resistance measurement method according to any one of claims 1 to 8.

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