Research On Thermal Conduction Mechanism And Thermal Measurement Of Thin Layer Interface

The thermal contact resistance of thin-layer interface is hot topic of concern in the fields of microelectronic device cooling and low-temperature superconducting thin film.As the size of integrated circuits continues to decrease and clock frequencies continue to increase,thermal management technology for microelectronic devices and modules is becoming more and more important.The accumulation of heat dissipation will not only limit the performance of the device,but also reduce its life and reliability.Thermal contact resistance refers to the phenomenon of heat dissipation formed between two solid materials,it is particularly important to study the thermal conduction mechanism and thermal measurement of the contact interface.However,at present,the scientific community has not formed any uniform measurement standard for interfacial thermal characteristics,and there is less way to eliminate interfacial thermal resistance.Most of the thermal measurement technologies rely on the contact between heat source of the equipment and the device under test for heat conduction to bring the entire system to a thermal steady state to analyze thermal characteristics.Therefore,the solid-solid contact interface formed between the heat source and the device under test plays an important role in the entire heat dissipation system.The change of total thermal resistance caused by the fluctuation of interfacial thermal resistance will inevitably interfere with the accuracy of internal thermal analysis of the device.In this paper,based on the transient temperature rise technique of electrical thermal resistance measurement,by preparing samples with different surface morphologies,a variety of solid-solid contact interface morphologies have been constructed,then the thermal conduction mechanism and thermal measurement of the thin-layer interface were studied under various experimental environmental conditions.The details are as follows:1.Independently developed an automatic test platform for thermal contact resistance.Including control circuit,working circuit,operation interface and industrial design,real-time interaction with the host computer software is realized through FPGA,and the stepper motor is driven to cooperate with the pressure sensor to generate the appropriate pressure to complete the fixing of device under test.When the device is artificially loaded through a mechanical fixture,the interfacial thermal resistance error caused by inconsistent fixed positions and uncertain pressure is solved.At the same time,the integration of the TTE series thermal resistance tester with this automated test platform has been completed,which has quickly improved the measurement efficiency and accuracy of thermal management technology.2.The thin-layer thermal conduction mechanism of solid-solid contact interface was studied.A variety of surface roughness iron samples were prepared by using a grinding and polishing machine and verified by atomic force microscopy to meet the expected standards.Then,a Si C Schottky diode nested in a round table-shaped copper case was customized for the sample as a heat source probe.The thermal resistance tester was used to thermally measure the different micro-interface morphologies formed by the probe in contact with various samples,and the tests were compared under vacuum and when different types of thermal interface materials were inserted in the solid-solid interface gap.The results show that heat transfer at the interface is always dominated by the heat conduction in the actual contact area of the solid-solid material,and the interface air rarely participates.As surface roughness increases,the actual contact area of the material decreases,and the contribution of interstitial air convection to the interface heat transfer increases,causing an increase in the interfacial thermal resistance of thin layer.3.Proposed a method to increase the accuracy of thermal analysis of devices.Based on the experimental results,for samples with a surface roughness Ra <6.4,when the interface formed by sample and heat source probe is filled with thermal interface materials such as thermal grease or phase change material,the interfacial thermal resistance showed good consistency.This has found a way for researchers to keep the interfacial contact thermal resistance constant: When conducting thermal analysis,it is necessary to uniformly treat the surface roughness of the sample within this range and fill the thermal interface material,thereby effectively ensuring the stability of the external interface contact thermal resistance,and improves the accuracy of thermal analysis of the system.