本文選題：LED散熱 + COB封裝　； 參考：《湖北大學(xué)》2014年碩士論文

【摘要】：應(yīng)用于照明領(lǐng)域的LED功率不斷提高,其散熱問題日益突出,開發(fā)新的封裝方式與散熱材料成為LED照明技術(shù)的核心問題。Chip on Board (COB)封裝因具有更小的熱阻而成為一種極具潛力的封裝形式。高可靠性的COB封裝基板必須具有高熱導(dǎo)率、高絕緣性及與芯片匹配的熱膨脹系數(shù)TEC；當(dāng)應(yīng)用于LED封裝時,為了獲得高出光率,封裝基板需兼具高反射率。 目前應(yīng)用于封裝的基板材料主要有金屬與陶瓷。金屬基板中鏡面鋁雖具有高熱導(dǎo)率與高反射率,然而其TEC失配與絕緣性問題導(dǎo)致其可靠性較差。陶瓷材料中氮化鋁(A1N)各方面性能優(yōu)越,但成本高,加工困難。基于陶瓷絕緣層的金屬基板(IMS)因結(jié)合了金屬與陶瓷的優(yōu)點而受到關(guān)注,例如Al-AIN基板：高熱導(dǎo)率、絕緣性與反射率。然而由于與A1N之間熱膨脹系數(shù)差異大,結(jié)合強度不高,高速率沉積A1N困難,而使得該技術(shù)未能有效應(yīng)用。為了獲得高絕緣、高導(dǎo)熱、熱膨脹系數(shù)匹配及高反射率的鋁基封裝基板,本文主要做了以下幾項工作： 1)利用磁控濺射制備A1N薄膜。在真空環(huán)境下,磁控濺射法能夠高速率沉積A1N薄膜,在現(xiàn)有數(shù)據(jù)資料的條件下,通過多次的實驗,并對薄膜的電學(xué)性能,膜厚、結(jié)晶態(tài)進行了測試、分析,最終尋找到了最佳的實驗條件：工作氣壓0.2Pa,氮氬比為1：1,濺射功率200W。 2)為了解決A1N與金屬鋁基結(jié)合強度差的問題,對金屬鋁進行陽極氧化預(yù)處理。在對氧化膜的膜厚、電學(xué)性能分析后,得到了陽極氧化膜膜厚、電阻率、擊穿電壓與氧化時間與環(huán)境溫度的關(guān)系。 3)為了制備高絕緣、高導(dǎo)熱、熱膨脹系數(shù)匹配及高反射率的金屬基板,在對金屬鋁基預(yù)處理后,利用磁控濺射在鋁基上沉積氮化鋁薄膜。在不同實驗參數(shù)下制得的金屬基板在結(jié)合力、電阻率、擊穿電壓、抗熱沖擊等方面的性能存在差異。為了能夠應(yīng)用在實際生產(chǎn),需要在低成本的前提下,選擇性能最佳的實驗參數(shù)：金屬鋁基底陽極氧化4h后,在工作氣壓0.2Pa,氮氬比為1：1,濺射功率200W的條件下濺射氮化鋁30min。 本文通過磁控濺射制備高抗電強度的A1N薄膜,在非晶薄膜中抗電強度達到700V/um。在鋁基底上沉積A1N之前,采用陽極氧化對鏡面拋光的鋁基底進行預(yù)處理,有效緩解了由A1N與A1之間TEC失配導(dǎo)致的A1N膜破裂的問題,同時提高了A1N薄膜與Al基底的結(jié)合強度。 實驗制得的復(fù)合基板陽極氧化鋁膜厚度為10um,氮化鋁膜lum時,耐壓值超過1350V,絕緣電阻率為1.7x106AIN薄膜與基底結(jié)合強度大于8Mpa；在260℃熱沖擊下,基板未發(fā)生形變,氮化鋁膜未破裂,電學(xué)特性無明顯變化。
[Abstract]:The power of LED used in lighting field is increasing, and the problem of heat dissipation is becoming more and more serious. The development of new packaging methods and heat dissipation materials has become the core problem of LED lighting technology. Chip on Board (COB) packaging has become a potential packaging form because of its smaller thermal resistance. The high reliability COB packaging substrate must have high thermal conductivity, high insulation and thermal expansion coefficient matching with the chip. When used in LED packaging, the packaging substrate must have high reflectivity in order to obtain high luminous rate. At present, the main substrate materials used in packaging are metals and ceramics. Although the mirror aluminum in the metal substrate has high thermal conductivity and high reflectivity, its TEC mismatch and insulation lead to poor reliability. Aluminum nitride (A1N) has excellent properties in ceramic materials, but its cost is high and it is difficult to process. Metal substrate (IMS) based on ceramic insulator has attracted much attention because of its advantages of combining metal with ceramics, such as Al-AIN substrate: high thermal conductivity, insulation and reflectivity. However, due to the large difference of thermal expansion coefficient with A1N, the low binding strength and the difficulty of high rate deposition of A1N, the technology can not be applied effectively. In order to obtain high insulation, high thermal conductivity, thermal expansion coefficient matching and high reflectivity aluminum based packaging substrate, the main work of this paper is as follows: 1) A1N thin films are prepared by magnetron sputtering. In vacuum environment, magnetron sputtering can deposit A1N thin films at a high rate. Under the condition of available data, the electrical properties, film thickness and crystalline state of the films are tested and analyzed through many experiments. Finally, the optimum experimental conditions were found: working pressure 0.2 Pa, ratio of nitrogen to argon 1: 1, sputtering power 200W.2) in order to solve the problem of poor bonding strength between A1N and aluminum, anodic oxidation pretreatment of metal aluminum was carried out. After analyzing the film thickness and electrical properties of the oxide film, the relationship between the thickness, resistivity, breakdown voltage and oxidation time and ambient temperature of the anodic oxide film is obtained. 3) in order to prepare high insulation and high heat conduction, the anodic oxide film thickness, resistivity, breakdown voltage and oxidation time are obtained. Aluminum nitride thin films were deposited on aluminum substrates by magnetron sputtering after pretreatment of metal substrates with matching thermal expansion coefficient and high reflectivity. The properties of the metal substrate fabricated under different experimental parameters are different in terms of adhesion, resistivity, breakdown voltage, thermal shock resistance and so on. In order to be used in practical production, the best experimental parameters should be selected on the premise of low cost: after anodizing of metal aluminum substrate for 4 hours, the working pressure is 0.2 Pa, the ratio of nitrogen to argon is 1: 1, the sputtering power is 200 W, and the sputtering power is 200 W for 30 min. A1N thin films with high electrical resistance were prepared by magnetron sputtering. The electrical resistance of A1N thin films in amorphous films was 700 V / m ~ (um). Before the deposition of A1N on the aluminum substrate, anodic oxidation was used to pretreat the mirror-polished aluminum substrate, which effectively alleviated the rupture of the A1N film caused by the mismatch between A1N and A1, and improved the bonding strength between A1N film and Al substrate. The thickness of anodic alumina film of the composite substrate is 10 um.When the aluminum nitride film lum, the voltage resistance is more than 1350V, the insulation resistivity is 1.7x106AIN film and the bonding strength between the substrate and the substrate is more than 8Mpa.The substrate is not deformed and the aluminum nitride film is not broken under the thermal shock at 260 鈩，

本文編號：2114712