A method and system for testing the thermal reflectance coefficient

Abstract

The application belongs to the technical field of heat reflection, and discloses a method and system for testing heat reflection coefficient. The application utilizes a high-precision cold and hot stage to accurately control the surface temperature of a test sample, obtains incident light information and reflected light information based on two detectors, and calculates the heat reflection coefficient of the test sample in a test temperature range in combination with temperature data. The application can measure a heat reflection coefficient with higher accuracy, and the system for testing heat reflection coefficient has simple structure, low cost, convenient operation, high working stability and strong practicability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of heat reflection, and more particularly relates to a method and system for testing a heat reflection coefficient. BACKGROUND

[0002] With the continuous development of electronic technology, high power density has become the main development direction of electronic devices. However, the performance and reliability of the device are deeply affected by the working temperature of the device. Therefore, the detection of the working temperature of the device is of great significance to the design and failure analysis of electronic devices. The heat reflection thermal imaging technology based on the heat reflection principle provides an effective technical means for obtaining the micro temperature distribution of the device. It has high spatial and temporal resolution and has been widely used in the fields of integrated circuit and semiconductor device temperature measurement. This technology can use ultraviolet to visible light band light source for temperature measurement, and its spatial resolution can reach the micro-nanometer level. Moreover, the spatial resolution of this technology can reach nanosecond level, and it can realize transient temperature measurement.

[0003] The basis of this non-contact technology is the heat reflection principle, that is, the change of the reflectivity of the surface of the sample to be measured caused by the change of the local temperature of the surface of the sample to be measured. For most materials, this change relationship is linear within a certain temperature range. The heat reflection coefficient (thermoreflectance coefficient) is an important parameter representing this linear relationship, denoted as C th , and the definition formula is:

[0004]

[0005] In the formula, R is the reference reflectivity, ΔR is the reflectivity change, and ΔT is the temperature change.

[0006] However, the heat reflection coefficient (C th ) is difficult to measure in actual testing process, and is easily affected by environmental factors, sample and other factors, which limits its accuracy in temperature measurement application. SUMMARY

[0007] The present application provides a method and system for testing the heat reflection coefficient, which solves the problem of poor accuracy of testing the heat reflection coefficient of the sample in the prior art.

[0008] The present application provides a method for testing the heat reflection coefficient, comprising the following steps:

[0009] Step 1, placing the test sample in a cold and hot table;

[0010] Step 2, adjust the cold and hot stage to the reference temperature, after thermal equilibrium, use the laser light source to generate the laser beam of the required wavelength for testing; the reflected light beam of the laser beam through the light splitting component is incident to the first detector, the first detector is connected with the signal processing device, and the reference incident light information is obtained through the signal processing device; the light beam transmitted through the light splitting component is focused to the surface of the test sample through the objective lens and reflected, and the reflected probe light beam is guided to the second detector through the light splitting component, the second detector is connected with the signal processing device, and the reference reflected light information is obtained through the signal processing device;

[0011] Step 3, adjust the cold and hot stage to the test temperature, after thermal equilibrium, continue to use the laser light source to generate the laser beam of the required wavelength for testing; the reflected light beam of the laser beam through the light splitting component is incident to the first detector, and the test incident light information is obtained through the signal processing device; the light beam transmitted through the light splitting component is focused to the surface of the test sample through the objective lens and reflected, and the reflected probe light beam is guided to the second detector through the light splitting component, and the test reflected light information is obtained through the signal processing device;

[0012] Step 4, based on the reference temperature, the reference incident light information, the reference reflected light information, the test temperature, the test incident light information and the test reflected light information, the thermal reflection coefficient of the test sample in the test temperature section is calculated, and the test temperature section is the temperature section from the reference temperature to the test temperature.

[0013] Preferably, the thermal reflection coefficient is calculated by the following formula:

[0014]

[0015] Wherein, C th is the thermal reflection coefficient of the test temperature section, T0 is the reference temperature, 0 is the reference reflected light information, r0 is the reference incident light information, T1 is the test temperature, R1 is the test reflected light information, and 1 is the test incident light information.

[0016] Preferably, the reference temperature, the reference incident light information and the reference reflected light information are recorded as reference information; the test temperature in step 3 is recorded as the first test temperature, and the test incident light information and the test reflected light information obtained at the first test temperature are recorded as the first test information;

[0017] The method for testing the thermal reflection coefficient further comprises:

[0018] In the step 3, after obtaining the first test information, the cold and hot stage is adjusted to the nth test temperature and the nth test information is obtained, the nth test information including test incident light information and test reflected light information obtained at the nth test temperature;

[0019] In the step 4, the thermal reflectance coefficient of the test sample in the nth test temperature section is calculated based on the reference information and the nth test information, the nth test temperature section being a temperature section from the reference temperature to the nth test temperature.

[0020] Preferably, in the step 2, after adjusting the cold and hot stage to the reference temperature and waiting for thermal equilibrium, the step further includes recording the position of a mark point of the test sample at the reference temperature.

[0021] In the step 3, after adjusting the cold and hot stage to the test temperature and waiting for thermal equilibrium, the step further includes resetting the mark point based on the position of the mark point, and then detecting the light information after the resetting is completed.

[0022] Preferably, the mark point is a dirty point or a damaged point on the surface of the test sample selected by observing the test sample through the objective lens at the reference temperature, and the mark point is reset by using a displacement stage based on the position of the mark point.

[0023] In another aspect, the present application provides a system for testing thermal reflectance coefficient, comprising a cold and hot stage, a laser light source, a light splitting assembly, an objective lens, a first detector, a second detector and a signal processing device.

[0024] The system for testing thermal reflectance coefficient is used to implement the steps in the method for testing thermal reflectance coefficient as described above.

[0025] Preferably, the system for testing thermal reflectance coefficient further comprises a first optical assembly and a second optical assembly.

[0026] The light splitting assembly comprises a first light splitting mirror and a second light splitting mirror arranged between the laser light source and the objective lens; the first optical assembly is arranged between the first light splitting mirror and the first detector, and comprises a first filter and a first lens arranged in sequence along an optical path; the second optical assembly is arranged between the second light splitting mirror and the second detector, and comprises a second filter and a second lens arranged in sequence along an optical path.

[0027] Preferably, the laser light source is a continuous tunable wavelength laser light source or a fixed wavelength laser light source.

[0028] Preferably, the signal processing device is an oscilloscope.

[0029] Preferably, the temperature control accuracy of the cold and hot stage is better than 0.1℃.

[0030] The one or more technical solutions provided in the present application have at least the following technical effects or advantages:

[0031] (1) The present application places the test sample in the cold and hot stage, and uses the high-precision cold and hot stage to accurately control the surface temperature of the test sample, which helps to obtain more accurate thermal reflectance.

[0032] (2) The present application uses the first detector and the second detector to detect the received incident light information r and the reflected light information R respectively, and R / r is the relative reflected light information. The relative reflected light information can be used to represent the reflectivity of the sample, and the thermal reflectance of the test sample in the test temperature range can be calculated by combining the temperature data. The test method of the thermal reflectance proposed in the present application can obtain relative reflected light information which is less affected by environmental factors and laser stability, improve the measurement accuracy of the change rate of reflected light information, and further obtain more accurate thermal reflectance.

[0033] (3) The present application records and resets the position of the mark point of the test sample during the test process, which can avoid the influence of the micro-deformation of the material itself caused by the change of the material temperature of the test sample on the test process, reduce the uncertainty and error in the process of measuring the change rate of reflected light information, and help to obtain more accurate thermal reflectance.

[0034] (4) The system for testing thermal reflectance provided by the present application has simple structure, low cost, convenient operation, high working stability and strong practicality.

[0035] (5) When the present application uses a continuously adjustable wavelength laser source, it can measure the thermal reflectance of multiple materials without replacing the laser, only by adjusting the wavelength, which improves the test efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 A structural schematic diagram of a system for testing thermal reflectance provided by Embodiment 1 of the present application. DETAILED DESCRIPTION

[0037] In order to better understand the above technical solutions, the above technical solutions will be described in detail in combination with the drawings and specific embodiments of the specification.

[0038] Embodiment 1:

[0039] Embodiment 1 provides a system for testing thermal reflectance, which is shown in Figure 1The application relates to a laser thermal reflectance coefficient testing device, which comprises a cold-hot stage 11, a laser light source 1, a light splitting assembly, a first optical assembly, a second optical assembly, an objective lens 4, a first detector 5, a second detector 6 and a signal processing device. The light splitting assembly comprises a first light splitting mirror 2 and a second light splitting mirror 3, a test sample 12 is arranged in the cold-hot stage 11, and the laser light source 1, the first light splitting mirror 2, the second light splitting mirror 3, the objective lens 4 and the test sample 12 are sequentially arranged. The first optical assembly is arranged between the first light splitting mirror 2 and the first detector 5, and the first optical assembly comprises a first filter 7 and a first lens 8 which are sequentially arranged along an optical path; the second optical assembly is arranged between the second light splitting mirror 3 and the second detector 6, and the second optical assembly comprises a second filter 9 and a second lens 10 which are sequentially arranged along an optical path. The first detector 5 and the second detector 6 are connected with the signal processing device.

[0040] The cold-hot stage 11 is used for accurately controlling the surface temperature of the test sample 12 arranged in the cold-hot stage 11, and the temperature control accuracy of the cold-hot stage 11 is better than 0.1 DEG C.

[0041] The laser light source 1 is a continuous adjustable wavelength laser light source or a fixed wavelength laser light source, and is used for generating a laser light beam with a required wavelength for testing. In addition, the number of the laser light source 1 can be multiple, and the light source can be replaced according to the testing requirement to obtain a laser light beam with a required wavelength.

[0042] The light splitting assembly is mainly used for leading out a new light beam, and is used together with other elements to form a testing light path of the application. Specifically, a part of the laser light beam is led out from an incident light path through the first light splitting mirror 2 and is received by the first detector 5 (that is, a new laser light beam is led out from the light path by using the first light splitting mirror 2, and the incident light is directly received by the first detector 5), and the incident light signal r is measured by combining the signal processing device. The laser light beam is focused on the surface of the test sample 12 through the objective lens 4 and is reflected, the reflected detection light beam is guided by the second light splitting mirror 3 and is finally received by the second detector 6, and the reflected light signal R is measured by combining the signal processing device.

[0043] The objective lens 4 is used for laser focusing, and the test sample 12 can also be observed by using the objective lens 4, a mark point of the test sample 12 is selected, and more accurate thermal reflectance coefficients are obtained. The mark point can be reset by using a displacement stage or other ways.

[0044] The first detector 5 is used for receiving the incident light signal, and the second detector 6 is used for receiving the reflected light signal after the surface of the test sample 12 is reflected, and the two detectors can adopt a small-size photoelectric signal detector.

[0045] The signal processing device is used to process the detection signals of the incident light signal and the reflected light signal, and obtain corresponding reference light information and test light information based on different temperature conditions, wherein the reference light information includes reference incident light information and reference reflected light information, and the test light information includes test incident light information and test reflected light information. The test light information can include one or more groups of test light information at different temperatures. The signal processing device can adopt an oscilloscope.

[0046] The thermal reflectance coefficient of the test sample at the test temperature section can be calculated based on the reference temperature, the reference incident light information, the reference reflected light information, the test temperature, the test incident light information and the test reflected light information. The test temperature section is a temperature section from the reference temperature to the test temperature. Alternatively, an additional data analysis device is used to calculate the thermal reflectance coefficient of the test sample at the test temperature section based on the above information.

[0047] When the thermal reflectance coefficient is tested by using the above system, first, the temperature of the cold and hot table 11 is adjusted to T0 (such as 30°C), and after thermal equilibrium, the reference state of the test sample 12 is determined, the position of the mark point of the test sample 12 at the reference temperature is recorded, the light path is made to pass light and the light beam is focused on the surface of the test sample 12, the reflected light signal R0 of the surface of the test sample is measured by the signal processing device (recorded as reference reflected light information), and the incident light signal r0 is recorded as reference incident light information); Then, the temperature of the cold and hot table 11 is adjusted to T1 (such as 70°C), and after thermal equilibrium, the mark point of the test sample 12 is reset by using the double-axis linear displacement table, the light path is made to pass light again and the light beam is focused on the surface of the test sample 12, the reflected light signal R1 of the surface of the test sample is measured by the signal processing device (recorded as test reflected light information), and the incident light signal r1 is recorded as test incident light information).

[0048] The reference state is the thermal reflectance coefficient C th The initial state of the test, each group of test results needs to be processed based on the reference state, that is, the formula The temperature change T1-T0 and the change of the reflected light signal are calculated based on the selected reference temperature T0, the reference reflected light information R0 and the reference incident light information r0.

[0049] The present application is based on the photoelectric detector to obtain the light information of the laser beam, and the principle is that the photoelectric detector can generate the voltage or current signal in direct proportion to the light intensity of the captured light beam, that is, the first detector captures the incident light beam to obtain the incident light information, and the second detector captures the reflected light beam to obtain the reflected light information, and then the relative reflected light information can be used to represent the reflectivity of the sample, and finally the thermal reflectance coefficient is obtained. The present application reduces the influence of environmental factors and the stability of the laser by testing the relative reflected light information of the reflected light signal and the incident light signal, so that the thermal reflectance coefficient calculated by the present application using the relative reflected light information is more accurate.

[0050] Specifically, the thermal reflectance coefficient in the present application is calculated by the following formula:

[0051]

[0052] Wherein, C th is the thermal reflectance coefficient of the test temperature section, T0 is the reference temperature, 0 is the reference reflected light information, r0 is the reference incident light information, T1 is the test temperature, R1 is the test reflected light information, and 1 is the test incident light information.

[0053] The system provided in Example 1 can realize the test of the thermal reflectance coefficient, and the method for testing the thermal reflectance coefficient corresponding to the system provided in Example 1 for testing the thermal reflectance coefficient is given as Example 2.

[0054] Example 2:

[0055] Example 2 provides a method for testing the thermal reflectance coefficient, mainly including the following steps:

[0056] Step 1, placing the test sample in the cold and hot table;

[0057] Step 2, adjusting the cold and hot table to the reference temperature, and after thermal equilibrium, using the laser light source to generate the laser beam of the required wavelength for testing; the reflected light beam of the laser beam after the light splitting component is incident to the first detector, the first detector is connected with the signal processing device, and the reference incident light information is obtained through the signal processing device; the light beam transmitted through the light splitting component is focused to the surface of the test sample through the objective lens and reflected, and the reflected probe light beam is guided to the second detector through the light splitting component, the second detector is connected with the signal processing device, and the reference reflected light information is obtained through the signal processing device;

[0058] Step 3, adjust the cold and hot stage to the test temperature, after thermal equilibrium, continue to generate a laser beam of a test required wavelength using the laser light source; the laser beam after reflection by the light splitting assembly is incident to the first detector, and the test incident light information is obtained by the signal processing device; the laser beam after transmission by the light splitting assembly is focused to the surface of the test sample by the objective lens and reflected, and the reflected probe light beam is guided to the second detector by the light splitting assembly, and the test reflected light information is obtained by the signal processing device;

[0059] Step 4, based on the reference temperature, the reference incident light information, the reference reflected light information, the test temperature, the test incident light information and the test reflected light information, the thermal reflectance coefficient of the test sample in the test temperature range is calculated, and the test temperature range is the temperature range from the reference temperature to the test temperature.

[0060] Wherein, the thermal reflectance coefficient is calculated by the following formula:

[0061]

[0062] Wherein, C th is the thermal reflectance coefficient of the test temperature range, T0 is the reference temperature, 0 is the reference reflected light information, r0 is the reference incident light information, T1 is the test temperature, R1 is the test reflected light information, and 1 is the test incident light information.

[0063] In addition, the reference temperature, the reference incident light information and the reference reflected light information are recorded as reference information; the test temperature in step 3 is recorded as the first test temperature, and the test incident light information and the test reflected light information obtained at the first test temperature are recorded as the first test information; the method for testing the thermal reflectance coefficient can further comprise: in step 3, after obtaining the first test information, continue to adjust the cold and hot stage to the nth test temperature and obtain the nth test information, the nth test information includes the test incident light information and the test reflected light information obtained at the nth test temperature; in step 4, based on the reference information and the nth test information, the thermal reflectance coefficient of the test sample in the nth test temperature range is calculated, and the nth test temperature range is the temperature range from the reference temperature to the nth test temperature.

[0064] For example, if the reference temperature is 30℃, and the cold and hot stage temperature is adjusted to 50℃, the test result is the thermal reflectance coefficient C th; the subsequent process can also control the cold and hot stage at 70, 90, 110, 130, 150℃, etc. The test result is the thermal reflectance C of the test sample at 30370℃, 30390℃, 303110℃, 303130℃, 303150℃, etc. th .

[0065] In order to avoid the influence of the micro-deformation of the material itself on the test process caused by the change of the material temperature of the test sample, reduce the uncertainty and error in the test, and further improve the test accuracy, in step 2, after the cold and hot stage is adjusted to the reference temperature and heat balance, the method can further include: recording the position of the mark point of the test sample at the reference temperature; in step 3, after the cold and hot stage is adjusted to the test temperature and heat balance, the method can further include: mark point resetting based on the position of the mark point, and then detecting the light information after the resetting is completed. Specifically, the mark point is a dirty point or a damaged point (i.e. a clear mark point) on the surface of the test sample selected after observing the test sample through the objective lens at the reference temperature; based on the position of the mark point, the mark point is reset by using the displacement stage, and the adjusting and resetting process can ensure a position accuracy of 2μm.

[0066] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application is described in detail with reference to the examples, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A method for testing the thermal reflectance factor, characterized in that, The method comprises the following steps: Step 1, placing a test sample on a cold and hot stage; Step 2, adjusting the cold and hot stage to a reference temperature, recording the position of a mark point of the test sample at the reference temperature after thermal equilibrium, and generating a laser beam of a required wavelength for testing by using a laser light source; the laser beam reflected by a light splitting component is incident on a first detector connected with a signal processing device, and reference incident light information is obtained by the signal processing device; the laser beam transmitted by the light splitting component is focused on the surface of the test sample by an objective lens and reflected, and the reflected probe light beam is guided to a second detector by the light splitting component, and reference reflected light information is obtained by the signal processing device; Step 3, adjusting the cold and hot stage to a test temperature, resetting the mark point based on the position of the mark point after thermal equilibrium, and continuing to generate a laser beam of a required wavelength for testing by using the laser light source; the laser beam reflected by the light splitting component is incident on the first detector, and test incident light information is obtained by the signal processing device; the laser beam transmitted by the light splitting component is focused on the surface of the test sample by the objective lens and reflected, and the reflected probe light beam is guided to the second detector by the light splitting component, and test reflected light information is obtained by the signal processing device; Step 4, calculating the thermal reflectance coefficient of the test sample in a test temperature range from the reference temperature to the test temperature based on the reference temperature, the reference incident light information, the reference reflected light information, the test temperature, the test incident light information and the test reflected light information; The thermal reflectance coefficient is calculated by the following formula: wherein, is the thermal reflectance coefficient for the temperature segment under test, is the reference temperature, is the reference reflected light information, is the reference incident light information, is the test temperature, is the test reflected light information, is the test incident light information; Wherein, the mark point is a dirty point or a damaged point on the surface of the test sample selected after observing the test sample by the objective lens at the reference temperature; the mark point is reset by using a displacement stage based on the position of the mark point.

2. The method for testing the heat reflection coefficient according to claim 1, characterized in that, The reference temperature, the reference incident light information and the reference reflected light information are recorded as reference information; The test temperature in step 3 is recorded as a first test temperature, and the test incident light information and the test reflected light information obtained at the first test temperature are recorded as first test information; The method for testing the thermal reflectance coefficient further comprises: In step 3, after obtaining the first test information, the cold and hot stage is continuously adjusted to an n-th test temperature, and an n-th test information is obtained, the n-th test information comprising test incident light information and test reflected light information obtained at the n-th test temperature; In step 4, the thermal reflectance coefficient of the test sample in an n-th test temperature range from the reference temperature to the n-th test temperature is calculated based on the reference information and the n-th test information.

3. The method for testing the heat reflection coefficient according to claim 1, characterized in that, The light splitting component comprises a first light splitting mirror and a second light splitting mirror arranged between the laser light source and the objective lens; A first optical assembly is arranged between the first beamsplitter and the first detector, and the first optical assembly comprises a first filter and a first lens arranged in sequence along an optical path; A second optical assembly is arranged between the second beamsplitter and the second detector, and the second optical assembly comprises a second filter and a second lens arranged in sequence along an optical path.

4. The method for testing the heat reflection coefficient according to claim 1, characterized in that, The laser light source is a continuous tunable wavelength laser light source or a fixed wavelength laser light source.

5. The method for testing the heat reflection coefficient according to claim 1, characterized in that, The signal processing device is an oscilloscope.

6. The method for testing the heat reflection coefficient according to claim 1, wherein, The temperature control precision of the cold and hot stage is better than 0.1 DEG C.

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