芯片互連層及封裝基板對大功率LED器件光熱性能的影響
發(fā)布時間：2018-10-25 06:29
【摘要】：LED具有尺寸小、亮度高、節(jié)能環(huán)保、壽命長、效率高等優(yōu)點,因此被廣泛應(yīng)用于交通信號燈、汽車后燈、液晶顯示、夜景照明及普通照明等,白光LED是繼白熾燈和熒光燈照明的新一代照明光源。但LED電光轉(zhuǎn)換效率較低,多余的電能在芯片內(nèi)轉(zhuǎn)化為熱能,若不能及時將熱量導(dǎo)出,會導(dǎo)致芯片結(jié)溫升高,從而影響LED器件散熱及可靠性。LED器件散熱問題成為制約其產(chǎn)業(yè)發(fā)展的主要瓶頸,因此需要優(yōu)化熱設(shè)計降低LED器件熱阻即提高LED散熱性能�；ミB材料及互連層空洞率(互連層空洞體積與互連層體積之比)對大功率LED散熱有著重要影響,大功率LED封裝基板對其擴散熱阻有一定的影響,因此互連材料、互連層空洞率及封裝基板是大功率LED熱設(shè)計中的關(guān)鍵。首先采用T3ster熱阻測試儀和ANSYS熱學(xué)仿真對LED器件及模型進(jìn)行熱學(xué)分析,以三種互連材料(金錫、錫膏及銀膠)對LED器件熱阻及芯片結(jié)溫的影響為例,分析了互連材料的熱導(dǎo)率及厚度對LED器件熱學(xué)性能的影響。實驗結(jié)果表明:互連層熱阻約占LED器件總熱阻的1/3,是影響LED結(jié)溫的主要因素之一;金錫互連質(zhì)量最好,其互連層熱阻最小;金錫共晶互連封裝器件互連層厚度最小,厚度越小對HP-LED散熱越有利。熱學(xué)模擬結(jié)果表明:互連材料熱導(dǎo)率升高到20 W/m K時,再提高互連材料熱導(dǎo)率對HP-LED散熱性能的影響不再顯著;互連層與芯片和基板的有效接觸面率從100%減小到10%,LED結(jié)溫升高了8.7%�；ミB材料的熱導(dǎo)率、厚度及互連層與芯片和基板的有效接觸面積均會影響LED芯片的結(jié)溫,因此在LED器件互連的設(shè)計中,需綜合考慮以上三個關(guān)鍵參數(shù),以實現(xiàn)散熱性能最佳化。其次研究了互連層空洞率對大功率LED的光學(xué)、熱學(xué)及電學(xué)性能的影響,通過實驗及仿真數(shù)據(jù)分析互連層空洞率對大功率LED的光學(xué)、熱學(xué)及電學(xué)性能的影響,實驗結(jié)果表明:共晶壓力從0 N增加到2 N,互連層空洞率從62.45%減小到16.53%,互連層熱阻(由互連材料及互連層空洞共同產(chǎn)生的熱阻)減小了82.7%;光通量隨著互連層熱阻的減小而增大,光通量增大了6.87%。有限元模擬結(jié)果表明:互連層空洞對LED芯片的熱應(yīng)力及熱應(yīng)變分布有較大影響,仿真結(jié)果發(fā)現(xiàn)互連層30%的空洞率使LED芯片的熱應(yīng)力及熱應(yīng)變分別增加了49.87%和50%;互連層空洞對有源層的電場強度及芯片最大電流密度均有較大影響,空洞使LED芯片最大電流密度及電場強度分別增大了161.06%和37.15%。最后研究了大功率LED封裝模塊擴散熱阻的影響因素。運用T3ster熱阻測試儀、有限元仿真及擴散熱阻計算公式對LED封裝模塊進(jìn)行熱學(xué)分析,對于LED單芯片擴散熱阻研究結(jié)果表明:①擴散熱阻在LED封裝模塊熱阻中占較大比重,約占60.49%;②熱源與基板之間的接觸面率是擴散熱阻的主要影響因素,接觸面率增大有利于減小擴散熱阻;③擴散熱阻隨著基板厚度的增大而先減小后變大,存在最佳基板厚度使得擴散熱阻最小;④芯片與基板的中心距對LED模塊的擴散熱阻及芯片結(jié)溫有著重要影響。對于LED多芯片封裝模型,運用有限元仿真LED多芯片溫度場分布,建立基板到空氣熱阻模型樹,提出了直接求解多芯片熱源擴散熱阻方法,模擬不同熱源位置對溫度場分布的影響。研究結(jié)果表明:①對比直接法與間接法求解多芯片熱源擴散熱阻,結(jié)果驗證了直接法的準(zhǔn)確性;②運用MATLAB求解了多芯片模塊溫度場結(jié)果,驗證了有限元仿真多芯片熱源溫度場分布的準(zhǔn)確性;③分析不同基板尺寸對擴散熱阻和總熱阻的影響,結(jié)果表明隨著基板面積的增大,擴散熱阻逐漸升高,而總熱阻卻逐漸下降。因此在基板尺寸設(shè)計時,需要綜合考慮導(dǎo)體熱阻、空氣對流熱阻與擴散熱阻,使總熱阻達(dá)到最佳值。
[Abstract]:The LED has the advantages of small size, high brightness, energy conservation, environmental protection, long service life, high efficiency and the like, and is widely applied to traffic signal lamps, automobile rear lights, liquid crystal display, night scene lighting and common lighting, and the like, and the white light LED is a new generation of illumination light sources which follow incandescent lamp and fluorescent lamp illumination. but the LED electro-optical conversion efficiency is low, the excess electric energy is converted into thermal energy in the chip, and if the heat can not be exported in time, the chip junction temperature is increased, thereby influencing the heat dissipation and the reliability of the LED device. LED device heat dissipation is the main bottleneck restricting its industrial development. Therefore, it is necessary to optimize the thermal design to reduce the thermal resistance of LED devices, that is, to improve the heat dissipation performance of LED devices. Interconnection material and interconnection layer void ratio (ratio of cavity volume of interconnect layer and interconnection layer volume) have an important effect on the heat dissipation of high-power LED, and the high-power LED package substrate has a certain influence on the diffusion resistance of the high-power LED, so that the interconnection material, The cavity rate of the interconnect layer and the package substrate are the key in high power LED thermal design. In this paper, the thermal analysis of LED devices and models was carried out using T3ster thermal resistance tester and ANSYS thermal simulation. The effects of thermal conductivity and thickness on the thermal properties of LED devices were analyzed by using three kinds of interconnect materials (gold tin, tin paste and silver glue) as examples. The experimental results show that the thermal resistance of the interconnect layer accounts for about 1/ 3 of the total thermal resistance of the LED device, which is one of the main factors affecting the junction temperature of the LED. The thermal simulation results show that when the thermal conductivity of the interconnect material rises to 20 W/ m K, the effect of increasing the thermal conductivity of the interconnect material on the heat dissipation performance of HP-LED is no longer significant; the effective contact surface rate of the interconnect layer and the chip and the substrate is reduced from 100% to 10%, and the temperature of the LED junction is increased by 8. 7%. The thermal conductivity, thickness and the effective contact area of the interconnection layer and the chip and the substrate can affect the junction temperature of the LED chip, therefore, in the design of the LED device interconnection, the above three key parameters need to be comprehensively considered, so as to realize the best heat dissipation performance. Secondly, the influence of the cavity rate on the optical, thermal and electrical properties of the high power LED is studied, and the influence of the cavity rate on the optical, thermal and electrical properties of the high power LED is analyzed through experiments and simulation data. The experimental results show that the eutectic pressure increases from 0 N to 2N, The cavity rate of interconnect layer is reduced from 62. 45% to 16.53%, and the thermal resistance of interconnect layer (thermal resistance generated by interconnect material and interconnect layer cavity) is reduced by 82.7%; the luminous flux increases with the decrease of thermal resistance of interconnect layer and the luminous flux increases by 6.87%. The results of the finite element simulation show that the thermal stress and thermal strain distribution of the LED chip are affected by the void ratio of the interconnect layer cavity, and the thermal stress and thermal strain of the LED chip are increased by 49. 87% and 50%, respectively. The electric field intensity of the active layer and the maximum current density of the chip are greatly influenced by the cavity of the interconnection layer, and the maximum current density and the electric field strength of the LED chip are increased by 161. 06% and 37.15% respectively. Finally, the influence factors of the diffusion thermal resistance of the high power LED package module were studied. The thermal analysis of LED package module using T3ster thermal resistance tester, finite element simulation and diffusion thermal resistance calculation formula was carried out. The results show that the thermal resistance of LED single chip is about 60. 49% of the thermal resistance of LED package module. the contact surface ratio between the heat source and the substrate is the main influencing factor of the diffusion thermal resistance, the contact surface rate is increased, and the diffusion thermal resistance is reduced; The center distance between the LED chip and the substrate has an important influence on the diffusion thermal resistance and the chip junction temperature of the LED module. For LED multi-chip package model, the temperature field distribution of LED multi-chip is simulated by finite element simulation, and a substrate-to-air thermal resistance model tree is built, and the influence of different heat source positions on temperature field distribution is simulated by directly solving the multi-chip heat source diffusion thermal resistance method. The results show that direct method and indirect method are used to solve the diffusion thermal resistance of multi-chip heat source, and the accuracy of direct method is verified. The results of temperature field of multi-chip module are solved by using MATLAB, and the accuracy of temperature field distribution of multi-chip heat source is verified by finite element method. The effect of different substrate sizes on diffusion thermal resistance and total thermal resistance is analyzed. The results show that with the increase of the area of the substrate, the diffusion thermal resistance increases gradually, but the total thermal resistance gradually decreases. Therefore, when the size of the substrate is designed, it is necessary to comprehensively consider the thermal resistance of the conductor, the convection thermal resistance of the air and the diffusion thermal resistance, so that the total thermal resistance reaches the optimum value.
【學(xué)位授予單位】：上海大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TN312.8
本文編號：2292900
[Abstract]:The LED has the advantages of small size, high brightness, energy conservation, environmental protection, long service life, high efficiency and the like, and is widely applied to traffic signal lamps, automobile rear lights, liquid crystal display, night scene lighting and common lighting, and the like, and the white light LED is a new generation of illumination light sources which follow incandescent lamp and fluorescent lamp illumination. but the LED electro-optical conversion efficiency is low, the excess electric energy is converted into thermal energy in the chip, and if the heat can not be exported in time, the chip junction temperature is increased, thereby influencing the heat dissipation and the reliability of the LED device. LED device heat dissipation is the main bottleneck restricting its industrial development. Therefore, it is necessary to optimize the thermal design to reduce the thermal resistance of LED devices, that is, to improve the heat dissipation performance of LED devices. Interconnection material and interconnection layer void ratio (ratio of cavity volume of interconnect layer and interconnection layer volume) have an important effect on the heat dissipation of high-power LED, and the high-power LED package substrate has a certain influence on the diffusion resistance of the high-power LED, so that the interconnection material, The cavity rate of the interconnect layer and the package substrate are the key in high power LED thermal design. In this paper, the thermal analysis of LED devices and models was carried out using T3ster thermal resistance tester and ANSYS thermal simulation. The effects of thermal conductivity and thickness on the thermal properties of LED devices were analyzed by using three kinds of interconnect materials (gold tin, tin paste and silver glue) as examples. The experimental results show that the thermal resistance of the interconnect layer accounts for about 1/ 3 of the total thermal resistance of the LED device, which is one of the main factors affecting the junction temperature of the LED. The thermal simulation results show that when the thermal conductivity of the interconnect material rises to 20 W/ m K, the effect of increasing the thermal conductivity of the interconnect material on the heat dissipation performance of HP-LED is no longer significant; the effective contact surface rate of the interconnect layer and the chip and the substrate is reduced from 100% to 10%, and the temperature of the LED junction is increased by 8. 7%. The thermal conductivity, thickness and the effective contact area of the interconnection layer and the chip and the substrate can affect the junction temperature of the LED chip, therefore, in the design of the LED device interconnection, the above three key parameters need to be comprehensively considered, so as to realize the best heat dissipation performance. Secondly, the influence of the cavity rate on the optical, thermal and electrical properties of the high power LED is studied, and the influence of the cavity rate on the optical, thermal and electrical properties of the high power LED is analyzed through experiments and simulation data. The experimental results show that the eutectic pressure increases from 0 N to 2N, The cavity rate of interconnect layer is reduced from 62. 45% to 16.53%, and the thermal resistance of interconnect layer (thermal resistance generated by interconnect material and interconnect layer cavity) is reduced by 82.7%; the luminous flux increases with the decrease of thermal resistance of interconnect layer and the luminous flux increases by 6.87%. The results of the finite element simulation show that the thermal stress and thermal strain distribution of the LED chip are affected by the void ratio of the interconnect layer cavity, and the thermal stress and thermal strain of the LED chip are increased by 49. 87% and 50%, respectively. The electric field intensity of the active layer and the maximum current density of the chip are greatly influenced by the cavity of the interconnection layer, and the maximum current density and the electric field strength of the LED chip are increased by 161. 06% and 37.15% respectively. Finally, the influence factors of the diffusion thermal resistance of the high power LED package module were studied. The thermal analysis of LED package module using T3ster thermal resistance tester, finite element simulation and diffusion thermal resistance calculation formula was carried out. The results show that the thermal resistance of LED single chip is about 60. 49% of the thermal resistance of LED package module. the contact surface ratio between the heat source and the substrate is the main influencing factor of the diffusion thermal resistance, the contact surface rate is increased, and the diffusion thermal resistance is reduced; The center distance between the LED chip and the substrate has an important influence on the diffusion thermal resistance and the chip junction temperature of the LED module. For LED multi-chip package model, the temperature field distribution of LED multi-chip is simulated by finite element simulation, and a substrate-to-air thermal resistance model tree is built, and the influence of different heat source positions on temperature field distribution is simulated by directly solving the multi-chip heat source diffusion thermal resistance method. The results show that direct method and indirect method are used to solve the diffusion thermal resistance of multi-chip heat source, and the accuracy of direct method is verified. The results of temperature field of multi-chip module are solved by using MATLAB, and the accuracy of temperature field distribution of multi-chip heat source is verified by finite element method. The effect of different substrate sizes on diffusion thermal resistance and total thermal resistance is analyzed. The results show that with the increase of the area of the substrate, the diffusion thermal resistance increases gradually, but the total thermal resistance gradually decreases. Therefore, when the size of the substrate is designed, it is necessary to comprehensively consider the thermal resistance of the conductor, the convection thermal resistance of the air and the diffusion thermal resistance, so that the total thermal resistance reaches the optimum value.
【學(xué)位授予單位】：上海大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TN312.8
【參考文獻(xiàn)】
相關(guān)期刊論文 前2條
1 苗洪利,王進(jìn),王晶,陳靜波,孟繼武;LED白光照明光源的研制[J];光電子·激光;2004年06期
2 許敏;;結(jié)合面接觸熱阻模型研究與應(yīng)用[J];機械制造;2006年01期
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