A patch type electrode and preparation method and material thermal conductivity testing method

Abstract

The present application is applicable to the field of thermal property testing technology of semiconductor materials, and provides a patch electrode and preparation method and material thermal conductivity testing method, wherein the patch electrode comprises: a metal strip, the metal strip is in a Π shape; a power pad and a test sampling pad, which are arranged on the metal strip; wherein, after the patch electrode is bonded to the material to be tested, an alternating current with a frequency of ω is applied to the power pad through a power-on device, and the test sampling pad is connected to collect a harmonic voltage with a frequency of 3ω through a collection device. The patch electrode is applied to the working scenario of testing the thermal conductivity of the chip by the 3ω test method, which improves the convenience and versatility of using the 3ω method to test the thermal conductivity of the chip.

Description

Technical Field

[0001] The present application belongs to the technical field of thermal property testing of semiconductor materials, and in particular relates to a patch-type electrode and a preparation method thereof, and a material thermal conductivity testing method. Background Art

[0002] The 3ω test method is mainly used to test the thermal conductivity of materials, especially in the testing of thermal properties of thin film materials at the micro-nano scale. This method is to make micro electrodes on the material to be tested for measurement, and the electrodes have the functions of heaters and sensors at the same time. In the current 3ω test method, metal electrodes are generally made on the surface of the material to be tested by semiconductor process methods such as evaporation and sputtering.

[0003] However, there are the following problems in making metal electrodes through semiconductor process methods: 1. Semiconductor process is relatively complex, which not only requires the manufacturer to have high process capabilities, but also requires the size and physical properties of the material to be tested to meet the process requirements. The conditions for testing through the above method are relatively harsh and less convenient.

[0004] 2. It is impossible to test finished semiconductor chips, because if you want to test the thermal conductivity of finished chips, the metal electrodes used for testing must be made during the chip manufacturing process. Once the chip is manufactured, it is impossible to make electrodes on the finished chip for measurement. The types of chips that can be tested by the above method are relatively small, and the versatility is poor.

[0005] In addition, some people have tried to use semiconductor technology to make it on a flexible film, and then use it together with the flexible film as a patch electrode. However, the use of flexible film electrodes, like making metal electrodes on chips, also needs to match the semiconductor process, which is not convenient. At the same time, the thermal conductivity of flexible film materials is often poorer than that of metal or semiconductor materials, which has a greater impact on the test results and reduces the accuracy of the thermal conductivity test results. Summary of the invention

[0006] In view of this, the embodiments of the present application provide a patch-type electrode and a preparation method and a material thermal conductivity testing method, which improve the convenience and versatility of material thermal conductivity testing using the 3ω testing method.

[0007] This application is implemented through the following technical solutions:

[0008] In the first aspect, an embodiment of the present application provides a patch electrode, comprising: a metal strip, the metal strip is in a Π shape; a powered pad and a test sampling pad, which are arranged on the metal strip; wherein, after the patch electrode is bonded to the material to be tested, an alternating current with a frequency of ω is applied to the powered pad through a powered device, and the test sampling pad is connected to the acquisition device to acquire a harmonic voltage with a frequency of 3ω.

[0009] In the embodiment of the present application, a patch electrode with a specific pattern is produced. The patch electrode is provided with a pad and a metal strip for sensing and heating. The 3ω thermal conductivity test can be performed by applying power to the pad. It is easy to transfer and can be directly applied to the processed chip. The patch electrode is used to test the material or chip under test, which improves the convenience and versatility of the material thermal conductivity test using the 3ω test method.

[0010] Based on the first aspect, in some embodiments, there are two power pads, which are respectively disposed at two ends of the metal strip.

[0011] Based on the first aspect, in some embodiments, there are two test sampling pads, which are arranged on one side of the metal strip and located between the two powered pads.

[0012] Based on the first aspect, in some embodiments, the patch electrode is made of platinum material.

[0013] Based on the first aspect, in some embodiments, the patch electrode has a thickness of 30 μm to 500 μm.

[0014] Based on the first aspect, in some embodiments, the surface of the patch electrode is further provided with a low-emissivity coating, and the emissivity of the coating is less than 0.3.

[0015] In the second aspect, an embodiment of the present application provides a method for preparing a patch electrode, comprising: laser cutting a metal film to obtain a patch electrode with a specific pattern; the patch electrode comprises a metal strip in a Π shape and a powered pad and a test sampling pad arranged on the metal strip; wherein, after the patch electrode is bonded to the material to be tested, an alternating current with a frequency of ω is applied to the powered pad through a power-on device, and the acquisition device is connected to the test sampling pad to acquire a harmonic voltage with a frequency of 3ω.

[0016] Based on the second aspect, in some embodiments, the method for preparing the patch electrode further includes: polishing the surface of the patch electrode.

[0017] Based on the second aspect, in some embodiments, after polishing the surface of the patch electrode, it also includes: forming a low-emissivity coating on the surface of the patch electrode through a coating process.

[0018] In a third aspect, an embodiment of the present application provides a material thermal conductivity testing method, which is applied to the patch electrode described in any one of the first aspects, and is characterized in that the material thermal conductivity testing method includes: bonding the patch electrode to the surface of the material to be tested; applying an alternating current with a frequency of ω to the powered pad through a power-on device; connecting the test sampling pad through a collection device to collect a harmonic voltage with a frequency of 3ω; obtaining the temperature rise information of the material to be tested based on the harmonic voltage, and calculating the thermal conductivity of the material to be tested based on the temperature rise information.

[0019] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0021] Figure 1 It is a schematic diagram of the application scenario of the patch electrode provided in the embodiment of the present application;

[0022] Figure 2 It is a schematic diagram of the patch type electrode pattern structure provided in the embodiment of the present application;

[0023] Figure 3 It is a schematic diagram of typical dimensions of patch-type electrodes provided in the embodiments of the present application;

[0024] Figure 4 is a flow chart of a patch electrode preparation method provided in an embodiment of the present application;

[0025] Figure 5 It is a flow chart of a thermal conductivity testing method using the above-mentioned patch-type electrode provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0027] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0028] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0029] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0030] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0031] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0032] The 3ω test method is mainly used to test the thermal conductivity of materials, especially in the testing of thermal properties of thin film materials at the micro-nano scale. In the prior art, 3ω measurement is generally performed by making microelectrodes on the material to be tested. The microelectrodes have the functions of heaters and sensors at the same time. The scenarios for thermal conductivity testing using the 3ω test method include: Figure 1 As shown, an alternating current I with a frequency of ω is applied to the metal points on the left and right sides. ω , causing the metal electrode to produce a temperature fluctuation with a frequency of 2ω. At this time, the electrode resistance will also change with a frequency of 2ω, and a harmonic voltage V with a frequency of 3ω will be generated under the action of the alternating current with a frequency of ω.3ω , sampling can be carried out through the middle metal point.

[0033] The traditional electrodes used in the current 3ω test method are made through semiconductor technology, and electrode patterns are formed on the surface of the material by means of evaporation, sputtering, etc. The advantage of this method is that it can achieve a smaller design. On the one hand, it reduces the impact of electrode thermal radiation on test accuracy, and on the other hand, the small thickness makes it easy to achieve the production of metal electrodes with larger resistance values. However, this method also has obvious defects. First, it has high requirements on the manufacturing process and material properties, requiring the tester to have the corresponding semiconductor process capabilities. Second, the electrodes must be made together with the chip manufacturing process. For a finished chip that has already been manufactured, this method can no longer be used.

[0034] To this end, the present invention provides a patch electrode, which is obtained by laser cutting an electrode pattern on a metal sheet. The produced patch electrode can be stored and transported independently, and can be used by bonding it to the surface of the material to be tested, which greatly improves the convenience and versatility of the 3ω test method.

[0035] like Figure 2 As shown, a patch electrode provided in an embodiment of the present application includes a metal strip 1, a power pad 2 and a test sampling pad 3. The metal strip 1 is in a Π shape; the power pad 2 and the test sampling pad 3 are arranged on the metal strip 1. The metal strip 1, the power pad 2 and the test sampling pad 3 are an integrally formed structure.

[0036] After the patch electrode is attached to the material to be tested, an alternating current with a frequency of ω is applied to the powered pad 2 through a power supply device, and the test sampling pad 3 is connected through a collection device to collect a harmonic voltage with a frequency of 3ω.

[0037] In some embodiments, there are two power pads 2 , which are respectively disposed at two ends of the metal strip 1 .

[0038] In some embodiments, there are two test sampling pads 3 , which are disposed on one side of the metal strip 1 and located between the two powered pads 2 .

[0039] In some embodiments, a typical size of a patch electrode is as follows: Figure 3 As shown, all dimensions are in the micrometer order. Among them, the width of the metal strip 1 is 40μm, the power pad 2 and the test sampling pad 3 can be a square of 400μm*400μm, the distance between the test sampling pad 3 and the metal strip 1 is 185μm, the width of the subsidiary metal strip between the test sampling pad 3 and the metal strip 1 is 40μm, the distance between the two subsidiary metal strips is 2000μm, and the distance between the power pad 2 and the nearest subsidiary metal strip is 400μm.

[0040] From the perspective of reducing the impact of thermal radiation, the size should be as small as possible. However, from the perspective of the feasibility of laser cutting and subsequent operations, if the size is too small, it is not suitable for processing, and it is easy to break during subsequent transfer, pasting and other operations.

[0041] 3ω electrodes are made of pure metals. Traditional methods use gold, silver, nickel, platinum, aluminum and other metals. The thickness of the metal electrode obtained by metal cutting will be much greater than the thickness of the semiconductor process. The greater the thickness and the larger the cross-sectional area, the smaller the resistance value. As shown in formula (1):

[0042]

[0043] Where ρ is the material resistivity, L is the resistor length, and S is the cross-sectional area.

[0044] In order to ensure that the electrode has sufficient resistance, on the one hand, the film thickness is reduced as much as possible, and on the other hand, metal platinum with a higher resistivity is selected to obtain a higher electrode resistance.

[0045] In some embodiments, the patch electrode is made of platinum material, and the thickness of the patch electrode can be 30μm to 500μm, generally 30μm is selected. The thinner the electrode thickness, the higher the resistance value can be obtained. When used in a high temperature environment, the surface of the patch electrode has a low emissivity coating. The emissivity should be less than 0.3, and the emissivity detection result is less affected and more accurate. The coating materials that can be selected include metal micropowder coatings, which disperse low-emissivity metal micropowders into resins, typically flaky aluminum powder coatings. Alternatively, an inorganic low-emissivity coating such as a phosphate binder can be used.

[0046] like Figure 4 As shown, a method for preparing a patch electrode provided in an embodiment of the present application includes steps 101 to 102.

[0047] Step 101: Laser cutting the metal film to obtain a patch electrode with a specific pattern. The patch electrode includes a metal strip in a shape of a letter "Π" and a power pad and a test sampling pad arranged on the metal strip. After the patch electrode is bonded to the material to be tested, an AC current with a frequency of ω is applied to the power pad through a power device, and the test sampling pad is connected to the acquisition device to acquire a harmonic voltage with a frequency of 3ω.

[0048] Step 102: Polishing the surface of the patch electrode.

[0049] Since the size of the patch electrode in the present invention is larger than that of the metal electrode made by ordinary semiconductor process, its thermal radiation effect will be more obvious. In order to reduce the influence of thermal radiation as much as possible, the surface of the patch electrode is polished to improve the flatness and cleanliness of the electrode surface, thereby reducing the surface emissivity of the material and achieving the effect of reducing thermal radiation.

[0050] In some embodiments, when the test condition is at a high temperature, a coating process may be used to form a low-emissivity coating on the surface of the patch electrode to reduce the emissivity of the electrode surface.

[0051] like Figure 5 As shown, the embodiment of the present application also provides a material thermal conductivity testing method using the above-mentioned patch electrode, including steps 201 to 204.

[0052] Step 201: Bonding the patch electrode to the surface of the material to be tested by bonding means.

[0053] In some embodiments, a thermally conductive adhesive with high thermal conductivity is used to bond the patch electrode to the surface of the material to be tested. To avoid oxidation and contamination of the electrode, the finished electrode needs to be stored in a purified and nitrogen environment. When in use, the electrode is bonded to the surface of the material to be tested by bonding. Since the thermal conductivity of the bonding material is often low, in order to minimize its impact on the test, a thermally conductive adhesive with the highest possible thermal conductivity is required for bonding. The thermal conductivity should be better than 2W / (mK). The thermally conductive adhesive that can be used is epoxy resin filled with aluminum nitride / graphene oxide, inorganic thermally conductive insulating adhesive based on phosphate and diamond, etc.

[0054] Step 202: Apply an alternating current with a frequency of ω to the powered pad through a powered device.

[0055] Applying an alternating current with a frequency of ω to the powered pad causes the electrode to produce a temperature fluctuation with a frequency of 2ω.

[0056] Step 203: Connect the test sampling pad with a collection device to collect the harmonic voltage with a frequency of 3ω.

[0057] When the electrode generates a temperature fluctuation with a frequency of 2ω, the resistance of the electrode will also change with a frequency of 2ω, and generate a harmonic voltage with a frequency of 3ω under the action of the alternating current of the frequency ω, and the above harmonic voltage is collected through the test sampling pad.

[0058] Step 204: obtaining temperature rise information of the material under test according to the harmonic voltage, and calculating the thermal conductivity of the material under test according to the temperature rise information.

[0059] The sampled 3ω frequency voltage contains temperature fluctuation information. By measuring the voltage, the temperature rise information can be obtained, as shown in formula (2):

[0060]

[0061] Among them, V 3ω is the harmonic voltage with a frequency of 3ω at both ends of the electrode, V ωis the fundamental voltage with frequency ω at both ends of the electrode, α R is the resistance temperature coefficient of the electrode itself.

[0062] When the electrode size is relatively small, the electrode on the surface of the material being tested can be regarded as a finite width line heat source on a semi-infinite solid surface, and its wave approximate solution is:

[0063]

[0064] Among them, P is the electrode heating power, l is the effective heating length of the electrode, κ is the thermal conductivity of the material being measured, b is the half width of the electrode, C is the volume heat capacity of the material being measured, and η is a constant.

[0065] From formula (3), we can see that there is a linear relationship between the electrode temperature fluctuation ΔT and ln(2ω), that is:

[0066]

[0067] Formula (2) is further used to obtain the electrode temperature rise at different frequencies. After plotting the curve, the slope coefficient K of the curve can be obtained, and then the thermal conductivity of the material can be obtained:

[0068]

[0069] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0070] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0071] In the embodiments provided in the present application, it should be understood that the disclosed devices / network equipment and methods can be implemented in other ways. For example, the device / network equipment embodiments described above are merely schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0072] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0073] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A patch electrode, characterized in that: include: A metal strip, wherein the metal strip is in a shape of a letter "Π"; wherein the metal strip is obtained by laser cutting on a metal sheet; The power-on pad and the test sampling pad are arranged on the metal strip; the metal strip, the power-on pad and the test sampling pad are an integrally formed structure; After the patch electrode is bonded to the material to be tested, an alternating current with a frequency of ω is applied to the powered pad through a power supply device, and the test sampling pad is connected through a collection device to collect a harmonic voltage with a frequency of 3ω.

2. The patch electrode according to claim 1, characterized in that: There are two power-on pads, which are respectively arranged at two ends of the metal strip.

3. The patch electrode according to claim 2, characterized in that: There are two test sampling pads, which are arranged on one side of the metal strip and located between the two powered pads.

4. The patch electrode according to claim 1, characterized in that: The patch type electrode is made of platinum material.

5. The patch electrode according to claim 1, characterized in that: The patch electrode has a thickness of 30 μm to 500 μm.

6. The patch electrode according to claim 1, characterized in that: The surface of the patch electrode is also provided with a low-emissivity coating, and the emissivity of the coating is ≤0.

3.

7. A method for preparing a patch electrode, applied to the patch electrode according to any one of claims 1 to 6, characterized in that: include: Laser cutting of metal film to obtain patch electrodes with specific patterns; The patch electrode comprises a metal strip in a shape of a letter "Π" and a power-on pad and a test sampling pad arranged on the metal strip; Among them, after the patch electrode is attached to the material to be tested, an alternating current with a frequency of ω is applied to the powered pad through a power-on device, and the test sampling pad is connected through a collection device to collect a harmonic voltage with a frequency of 3ω.

8. The method for preparing a patch type electrode according to claim 7, characterized in that: Also includes: The surface of the patch electrode is polished.

9. The method for preparing a patch type electrode according to claim 7, characterized in that: After polishing the surface of the patch electrode, the method further comprises: A low-emissivity coating is formed on the surface of the patch-type electrode through a coating process.

10. A material thermal conductivity testing method, applied to the patch electrode as claimed in any one of claims 1 to 6, characterized in that: The material thermal conductivity testing method includes: Bonding the patch electrode to the surface of the material to be tested; Applying an alternating current with a frequency of ω to the powered pad through a powered device; Connecting the test sampling pad with a collection device to collect harmonic voltage with a frequency of 3ω; The temperature rise information of the material under test is obtained according to the harmonic voltage, and the thermal conductivity of the material under test is calculated according to the temperature rise information.

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