Device for measuring thermal contact resistance and thermal conductivity of interface
By designing a measuring device including a bracket, a loading device, a heating module and a cooling module, the problems of unstable and inaccurate contact thermal resistance measurement at the copper-copper interface in the prior art are solved, and fast and accurate thermal resistance and thermal conductivity measurement are achieved.
Patent Information
- Application Number
- CN202420611266.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-27
- Publication Date
- 2025-04-15
- Estimated Expiration
- 2034-03-27
AI Technical Summary
The existing devices and methods for measuring contact thermal resistance at the copper-copper interface have problems such as long steady-state conditions and unstable experimental measurements, which leads to inaccurate and reliable measurements.
A measuring device including a bracket, a loading device, a heating module and a cooling module is designed to achieve stable contact of the copper rod through linear bearings, spherical joints and coaxial pressure sensors, and heat and cool with ceramic heating sheets and inverted "U" copper blocks to quickly achieve steady-state conditions.
The device can quickly and stably measure thermal resistance and thermal conductivity of copper-copper contacts, improving the accuracy and reliability of measurements, and complying with ASTM D5470 standards.
Smart Images
Figure CN222762109U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of heat transfer, and in particular relates to a device for measuring interface contact thermal resistance and thermal conductivity. Background Art
[0002] With the rapid development of 5G technology, the miniaturization and integration of electronic devices have become the mainstream trend, which leads to excessive concentration of heat generated during the operation of the devices. Higher operating temperatures will lead to decreased stability, performance and life of electronic devices. Therefore, how to achieve efficient thermal management and heat dissipation of devices has become the key and has important application value in actual production.
[0003] At present, there are various technologies for measuring the contact thermal resistance of materials, which are mainly divided into two categories: transient method and steady-state method. Transient methods include photoacoustic technology, thermal reflection technology, laser flash technology, photothermal technology, infrared thermal imaging and 3ω method. Although the transient measurement method has the advantages of short measurement cycle and fast response, its measurement accuracy is not ideal and its theoretical derivation is complicated. The steady-state method based on ASTM standard D5470 is generally regarded as the standard method for measuring contact thermal resistance due to its high measurement accuracy and simple operation.
[0004] Copper has always been regarded as an excellent device interconnect medium. Copper-copper bonding has a wide range of applications due to its excellent characteristics of low resistivity, high thermal conductivity, high thermal cycle performance and strong mechanical connection. For example, copper-copper interface connection is widely used in miniaturized high-precision electronic products and precision instruments. However, the devices and methods for measuring the contact thermal resistance at the copper-copper interface in the prior art have problems such as a long time to reach the steady-state condition and unstable experimental measurement. Therefore, it is necessary to improve the existing measurement device to make the measurement results more accurate and reliable. Utility Model Content
[0005] The utility model aims to provide a device for measuring interface contact thermal resistance and thermal conductivity, which can measure the contact thermal resistance of a contact interface, especially a copper-copper interface, and improves the stability and accuracy of the measurement.
[0006] Specifically, the utility model provides the following technical solutions:
[0007] A device for measuring contact thermal resistance and thermal conductivity, comprising:
[0008] A bracket, the bracket comprising a base plate at the bottom, a column is arranged on the base plate for support, a main plate and a sub-plate located below the main plate are also arranged on the upper part of the column;
[0009] The loading device includes a linear bearing, two upper and lower spherical joints and a coaxial pressure sensor; the linear bearing passes through a through hole between the secondary disk and the main disk and extends out of the upper end of the main disk; the upper spherical joint is arranged at the lower end of the linear bearing and below the secondary disk, and the lower spherical joint is arranged between the base disk and the coaxial pressure sensor;
[0010] The heating module is arranged at the lower end of the upper spherical joint, and the upper copper rod and the lower copper rod whose contact thermal resistance is to be measured are connected below; the upper copper rod and the lower copper rod are evenly provided with a plurality of thermocouple jacks on their surfaces;
[0011] A cooling module is located above the coaxial pressure sensor and in contact with the lower end of the lower copper rod;
[0012] A knob is provided on the upper end of the linear bearing of the loading device. The knob is controlled to rotate to drive the screw, and the screw drives the screw nut, thereby driving the auxiliary disk to move vertically downward, so that the two copper rods have good thermal contact at the interface.
[0013] In one embodiment of the present invention, a heat insulation block is further provided between the spherical joint and the heating module.
[0014] In one embodiment of the present invention, the upper copper rod and the lower copper rod are identical rectangular parallelepipeds, and the cross-section of the upper copper rod and the lower copper rod is 10 mm×10 mm, and the length is 50 mm to 100 mm.
[0015] In one embodiment of the present invention, the heating module is composed of a ceramic heating plate, and the ceramic heating plate is selected from a 96% alumina ceramic substrate; the size of the ceramic heating plate is 20 mm×20 mm×2 mm.
[0016] In one embodiment of the present invention, the cooling module is a copper block with an inverted "U"-shaped structure; three columns are arranged between the base plate and the main plate.
[0017] In one embodiment of the utility model, four thermocouple jacks are respectively provided at 6mm, 26mm, 46mm and 66mm from the contact interface of the copper rods on the upper copper rod and the lower copper rod, with a jack diameter of 1mm and a hole depth of 5mm, extending to the center of the copper rod;
[0018] Preferably, the thermocouple socket is filled with thermally conductive grease.
[0019] In one embodiment of the utility model, the heating module is a rectangular box made of fine copper, with a ceramic heating plate embedded inside, and the heating module forms a non-bonded joint with the upper copper rod; a quartz insulation sheet is placed above the rectangular box.
[0020] In one embodiment of the utility model, the lower copper rod has two small copper rods extending into the cooling module to increase the contact area between the lower copper rod and the ice-water mixture in the cooling module.
[0021] Excellent effects of the utility model:
[0022] The utility model provides a device and method for measuring the contact thermal resistance and thermal conductivity of a material. According to the ASTMD5470 standard, a copper-copper contact thermal resistance and copper thermal conductivity measuring device is built. It is an axial steady-state heat flow method measuring instrument, which can quickly measure the contact thermal resistance at the interface of two identical or different materials, and can accurately measure the intrinsic thermal conductivity of the material at the same time. The two data can be obtained at the same time. The heat flow steady-state measuring device provided by the utility model has a simple structure and is easy to build. The measuring method is simple to operate. At the same time, the data collection is efficient and easy to process. It has the advantages of high measurement accuracy and good stability. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 It is a structural schematic diagram of the contact thermal resistance and thermal conductivity measuring device of the utility model;
[0024] Figure 2 It is a schematic diagram of temperature variation with time;
[0025] Figure 3 This is a schematic diagram of the change of thermal conductivity of a material interface with contact pressure measured by the measuring device of the utility model;
[0026] Figure 4 The utility model is used to measure the change of the thermal conductivity of the material interface along with the interface temperature by using the measuring device. DETAILED DESCRIPTION
[0027] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be emphasized that the specific embodiments described here are only used to better illustrate the utility model, which are some embodiments of the utility model, not all embodiments, and are not used to limit the utility model. In addition, the technical features involved in the embodiments of the utility model described below can be combined with each other as long as they do not conflict with each other.
[0028] like Figure 1 As shown, the utility model provides a device for measuring contact thermal resistance and thermal conductivity, including a bracket, a loading device, a heating module 7 and a cooling module 9, wherein the bracket includes a base plate 1 located at the bottom, a column 2 for support arranged on the base plate 1, a main plate 3 arranged on the upper part of the column 2, and a sub-plate 5 below the main plate 3.
[0029] Preferably, three columns 2 are arranged between the base plate 1 and the main plate 3 .
[0030] Specifically, the loading device includes a linear bearing 4, two upper and lower spherical joints 6 and a coaxial pressure sensor 10. The linear bearing 4 passes through the through hole between the sub-disk 5 and the main disk 3 and extends out of the upper end of the main disk 3; the upper spherical joint 6 is arranged at the lower end of the linear bearing 4 and is located below the sub-disk 5, and the lower spherical joint 6 is arranged between the base disk 1 and the coaxial pressure sensor 10.
[0031] Specifically, the heating module 7 is arranged at the lower end of the upper spherical joint 6, and the upper copper rod 8 and the lower copper rod 81 of the contact thermal resistance to be measured are connected below. Preferably, the heating module 3 is composed of a ceramic heating plate, and the ceramic heating plate is selected from a 96% alumina ceramic substrate. The size of the ceramic heating plate can be, for example, 20mm×20mm×2mm.
[0032] In one embodiment, Figure 1 As shown, the heating module is a rectangular box made of fine copper, with a ceramic heating sheet buried inside. The heating module forms a non-bonded joint with the upper copper rod, and a quartz insulation sheet needs to be placed above the rectangular box. The cooling module 9 is located above the coaxial pressure sensor 10 and contacts the lower end of the lower copper rod 81.
[0033] Preferably, the cooling module is a copper block with an inverted "U"-shaped structure. Two small copper rods are formed at the lower end of the lower copper rod, and the small copper rods extend into the cooling module to increase the contact area between the lower copper rod and the ice-water mixture in the cooling module and improve the cooling effect.
[0034] For example, the upper copper rod 8 and the lower copper rod 81 are the same rectangular parallelepiped, and the cross-section of the upper copper rod and the lower copper rod is 10 mm×10 mm, and the length is 50 mm to 100 mm.
[0035] The utility model limits the length and cross-sectional area of the copper rod within the above range, which is beneficial to the heat flow transmission in the copper rod and improves the accuracy of equipment measurement.
[0036] Specifically, two copper rods are arranged between the heating module and the cooling module, and multiple thermocouple sockets are evenly arranged on the upper copper rod 8 and the lower copper rod 81. Preferably, the thermocouple sockets are filled with high thermal conductivity grease (Japan Shin-Etsu 7921 thermal grease).
[0037] Among them, the upper copper rod 8 and the lower copper rod 81 are respectively provided with 4 thermocouple jacks at 6mm, 26mm, 46mm and 66mm away from the copper rod contact interface, with a jack diameter of 1mm and a hole depth of 5mm, reaching the center of the copper rod.
[0038] Among them, a knob is set on the upper end of the linear bearing 4 of the loading device, and the knob can be manually rotated to drive the screw, and the screw drives the screw nut, thereby driving the auxiliary disk 5 to move vertically downward, so that the two copper rods form good thermal contact at the interface.
[0039] The utility model also provides a method for measuring contact thermal resistance and thermal conductivity using a measuring device, comprising the following steps:
[0040] S1, start the loading device, heating module and cooling module; the screw is driven to rotate by controlling the top knob above the loading device, and the screw drives the screw nut to drive the sub-disk to move vertically downward, so that the upper copper rod and the lower copper rod are in thermal contact at the contact interface;
[0041] S2, after the system is running normally and stably, temperature data collection is carried out for at least one hour; during the collection process, the readings of 8 thermocouples are recorded every 60 seconds, the data are recorded three times in succession, and the average value of the three data is taken as the temperature data of the time period;
[0042] S3, plotting the data measured in step S2 as a time-temperature curve, obtaining the temperature drop ΔT at the interface based on the linear correlation of the temperatures at the eight measurement points, and then using Fourier's law to calculate the heat flux density q of the two copper samples 1 and q 2 , the specific formula is as follows:
[0043]
[0044] q=(q 1 +q 2 ) / 2;
[0045]
[0046] Among them, the heat flux density q is the heat flow through the copper rod per unit area per unit time, κ is the thermal conductivity of the copper rod, is the temperature gradient; the interface thermal conductivity G is the inverse of the interface contact thermal resistance R; the heat flux density q through the interface is the heat flux density q of the two samples 1 and q 2 The average value of .
[0047] In one embodiment of the present invention, the pressure range of the loading device is 1-9 MPa; the heating temperature range of the heating module is 20°C-180°C.
[0048] Example 1
[0049] use Figure 1 The measurement setup shown measures the thermal contact resistance and thermal conductivity of two copper bars.
[0050] The measuring device is as follows: two high thermal conductivity rectangular copper samples (the cross-sectional area of the two copper rods is 10 mm × 10 mm, the length is 80 mm, and each copper rod is provided with 4 thermocouple sockets; the core part uses pure copper material, which has better electrical conductivity, thermal conductivity and excellent mechanical properties), a heating block, a cooling block, 8 thermocouples, a loading device, and an insulating block located between the ball joint and the heating module.
[0051] Two identical copper rods with high thermal conductivity as described above are placed between the heating module and the cooling module to achieve axial downward heat flow. The heating module is a rectangular box made of fine copper with a ceramic heating plate embedded in it, forming a bond-free joint with the upper copper rod. A quartz insulation sheet is placed above the rectangular box to maximize axial heat transfer. In order to improve the heat dissipation efficiency, two small copper rods are formed at the bottom of the lower copper rod sample and extend into the ice-water mixture of the cooling module to increase the contact area with the ice-water mixture and improve the cooling effect.
[0052] The core components are connected to the stainless steel bracket with a universal floating ball joint to achieve precise alignment. Three columns connect the main plate, auxiliary plate and base plate to facilitate the insertion and removal of samples.
[0053] The measurement steps are as follows:
[0054] 1) Before operation, gently clean the surface of the upper copper rod and the lower copper rod with alcohol, acetone, and isopropyl alcohol in turn. The thermocouple sockets (diameter 1.1mm) of the two copper rods are filled with high thermal conductivity grease (Japan Shin-Etsu 7921 thermal conductive silicone grease). The RS pro K-type thermocouple with extremely low temperature drift, extremely accurate, and extremely stable is inserted into the four thermocouple sockets of the copper rod, extending to its center line, with a depth of 5mm. The four thermocouple sockets of the upper copper rod and the lower copper rod are located at 6mm, 26mm, 46mm, and 66mm from the bottom of the upper copper rod and the top of the lower copper rod, respectively. The thermocouple completes the acquisition of temperature changes over time through the Keithey DAQ6510 data acquisition device, and can monitor 8 signals simultaneously.
[0055] 2) Start the loading device, heating module and cooling module at the same time, and rotate the knob on the top of the frame above the loading device. The knob drives the screw, the screw drives the screw nut, and the screw nut drives the sub-disk to move vertically downward, so that the upper and lower copper rods form good thermal contact at the contact interface. The pressure gauge is connected to the weighing controller, and the controller displays the loading value, with a measurement range of 1 to 9Mpa.
[0056] The ceramic heating module is connected to a Tektronix PWS2323 DC power supply with a measurement range of 0-32V. The maximum temperature of the ceramic heating plate in the heating module can reach 200°C. To ensure the continuity and stability of the operation of the heating plate, the safe operation interval is 20-180°C.
[0057] 3) The system keeps running normally until the sample reaches a stable temperature, and the pressure and temperature of 8 thermocouple positions are read simultaneously. If the temperature change at each thermocouple position does not exceed 0.1°C within 15 minutes, the temperature is considered to be in a stable state. Figure 2 As shown, when the pressure on the contact surface is 1.34 MPa, the system reaches thermal equilibrium after running for 70 minutes.
[0058] 4) Change the load of the loading device and obtain stable temperature readings in the same way. Repeat the measurement three times under the same contact, temperature and pressure conditions to verify the repeatability and reliability of the measurement data.
[0059] Heat transfer can occur at interfaces through discrete points of contact between two solids in the form of conduction, or through gaps at interfaces in the form of conduction, convection, and radiation. Relative heat loss is a key factor affecting the accuracy of contact heat transfer measurements. At temperatures below 600°C, radiation accounts for less than 1-2% of the total heat transfer.
[0060] The maximum temperature in Example 1 does not exceed 150°C, and the contribution of thermal radiation can be ignored in this case. Under vacuum conditions, the thermal convection and thermal conduction in the contact surface gap can be completely ignored. Therefore, the interface thermal conductivity G is approximately equal to the point contact thermal conductivity of the solid.
[0061] Considering the ratio of the transverse heat transfer rate to the longitudinal heat transfer rate, the utility model regards the steady-state heat transfer in the system as one-dimensional, that is, there is no radial temperature gradient. The heat flow flows from the upper copper rod to the lower copper rod in one dimension, and the temperature is linearly distributed in each copper rod. At the same time, due to the incomplete contact at the interface, the temperature is reduced. The calculation of the contact thermal resistance is as follows:
[0062]
[0063] q=(q 1 +q 2 ) / twenty two)
[0064]
[0065] Among them, the heat flux q is the heat passing through per unit area and per unit time, κ is the thermal conductivity of the copper rod, is the temperature gradient. The interface thermal conductivity G is the inverse of the contact thermal resistance R. The heat flux density q through the interface is the heat flux density q of the two samples in equation (2) 1 and q 2 The linear correlation of the temperatures at the eight measurement points can be used to obtain the temperature drop ΔT at the interface. Based on this, Fourier's law can be used to calculate q 1 and q 2 .
[0066] The copper-copper contact surface experiment was carried out under room temperature with a load of 1 to 9 MPa. The loading device applied pressure uniformly at the interface and converted the load value into a pressure value based on the calibrated contact area. The effect of contact pressure on contact thermal conductivity is shown in Figure 3 As shown. Generally speaking, in the range of 1 to 9 MPa, as the copper-copper interface pressure increases, the contact thermal conductivity increases. The magnitude of the applied load directly affects the degree of deformation of the micro-bumps at the contact interface. The greater the load, the greater the degree of deformation, and the larger the actual contact area, resulting in an increase in contact thermal conductivity. When the load value exceeds the elastic limit of the material, irreversible plastic deformation occurs at the interface. Therefore, under the same temperature and pressure conditions, the interface thermal conductivity after plastic deformation is greater than the value before plastic deformation.
[0067] Thermal loads are essentially the same as mechanical loads, and the contact thermal resistance can be improved by changing the morphology of the contact interface. Figure 4 As shown in the figure, for the interface formed by the contact of the same materials, under a certain pressure, as the interface temperature increases, the contact thermal conductivity will increase. Due to the change in interface temperature, the intrinsic thermal conductivity and mechanical properties such as elastic modulus and hardness of the two solid samples will also change accordingly. Ultimately, the increase in interface temperature leads to interface deformation, which is manifested as an increase in the actual contact area, resulting in an increase in contact thermal conductivity.
[0068] Therefore, the measuring device and method provided by the utility model can stably and accurately measure the contact thermal resistance of the sample, and are simple to operate and have a wide range of applications, and can realize the measurement of contact thermal resistance under different pressures and temperatures.
[0069] The above is only a preferred application implementation of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.
Claims
1. A device for measuring contact thermal resistance and thermal conductivity, characterized in that: include: A support, the support comprising a base plate (1) located at the bottom, a column (2) being arranged on the base plate (1) for support, a main plate (3) and a secondary plate (5) located below the main plate (3) being arranged on the upper part of the column (2); The loading device comprises a linear bearing (4), two upper and lower spherical joints (6) and a coaxial pressure sensor (10); the linear bearing (4) passes through a through hole between the auxiliary disk (5) and the main disk (3) and extends out of the upper end of the main disk (3); the upper spherical joint (6) is arranged at the lower end of the linear bearing (4) and below the auxiliary disk (5), and the lower spherical joint (6) is arranged between the base disk (1) and the coaxial pressure sensor (10); The heating module (7) is arranged at the lower end of the upper spherical joint (6), and is connected to an upper copper rod (8) and a lower copper rod (81) whose contact thermal resistance is to be measured. A plurality of thermocouple jacks are evenly arranged on the surface of the upper copper rod (8) and the lower copper rod (81); A cooling module (9) is located above the coaxial pressure sensor (10) and is in contact with the lower end of the lower copper rod (81); The upper end of the linear bearing (4) of the loading device is provided with a knob, which is controlled to rotate to drive the screw, and the screw drives the screw nut, thereby driving the auxiliary disk (5) to move vertically downward, so that the two copper rods are in good thermal contact at the interface.
2. The measuring device according to claim 1, characterized in that The upper copper rod (8) and the lower copper rod (81) are identical rectangular parallelepipeds with a cross section of 10 mm×10 mm and a length of 50 mm to 100 mm.
3. The measuring device according to claim 1, characterized in that The heating module (7) is composed of a ceramic heating plate, and the ceramic heating plate is selected from a 96% alumina ceramic substrate; the size of the ceramic heating plate is 20 mm×20 mm×2 mm.
4. The measuring device according to claim 1, characterized in that The cooling module (9) is a copper block with an inverted "U"-shaped structure; three columns (2) are arranged between the base plate (1) and the main plate (3).
5. The measuring device according to claim 1, characterized in that A heat insulation block is also provided between the spherical joint (6) and the heating module (7).
6. The measuring device according to claim 1, characterized in that Four thermocouple jacks are respectively provided on the upper copper rod (8) and the lower copper rod (81) at 6 mm, 26 mm, 46 mm and 66 mm from the copper rod contact interface, with the jack diameter being 1 mm and the hole depth being 5 mm, extending to the center of the copper rod.
7. The measuring device according to claim 6, characterized in that The thermocouple socket is filled with thermally conductive grease.
8. The measuring device according to any one of claims 1 to 7, characterized in that The heating module is a rectangular box made of fine copper, with a ceramic heating sheet buried inside. The heating module forms a non-bonded joint with the upper copper rod; a quartz insulation sheet is placed above the rectangular box.
9. The measuring device according to any one of claims 1 to 7, characterized in that The lower copper rod has two small copper rods extending into the cooling module to increase the contact area between the lower copper rod and the ice-water mixture in the cooling module.