外文翻譯---大功率白光LED封裝工藝技術(shù)與研制

1、.附錄A Research&Fabrication of Packaging Technology for High Power White LEDComparing with the traditional incandescent and fluorescent lighting, the high Power white LED has many significant incomparable advantages such as energy saving, envirorunental protection, long life and so on. It represen

2、ts the development direction of green lighting, and is moving into the field of lighting rapidly. From the packaging technology of 1 W high-bower white LED, the cost and performance of several methods were analyzed and compared for white light LED. Based on this, using the“blue chip&YAG phosphor

3、" for producing white light LED is the final selection with its good perfounance and proper price. The results show that in improving the light emitting efficiency, unilounity and stability of high-power white LED, it needs further development of new materials and new technology.IntroductionLED

4、 use semiconductor chips of solid as light emitting materials, the use of electric light-emitting. As a light source, LED's advantages is in energy saving, environmental protection and long-lived three aspects. LED does not depend on heating filament to light-emitting, energy conversion efficien

5、cy is very high, in theory only 10% of the energy consumption of incandescent. compared with fluorescent, LED can be up to 50% of the energy saving effect. Special survey showed that the annual electricity consumption of China's lighting is more than 300 billion, to replace all incandescent lamp

6、s with LED or in part or to replace the fluorescent lamp, can save 1 / 3 of the lighting electricity, means that the saving of 1 000 billion kwh, representing the full-year's generating capacity of Three Gorges Project which investment of more than 200 billion. Using LED to replace fluorescent l

7、amps, bamboo lamps to avoid the breakdown of a spill of mercury pollution, moreover waste and manufacturing backplane LED (Copper Clad Aluminum) reuse can be recycled. LED by solid package, the structure is deep-set , life expectancy can be up to h. In addition, LED also has a low operating voltage,

8、 power consumption in small, high luminous efficiency, response time is very short (ns-grade), pure light color, light weight, small size, such as a series of characteristics of rapid development, especially high-power high-brightness white light LED of the invention, by the insider as the "lig

9、hting the area of the third revolution."following make fire lighting, after Edison invented the lamp .White LED production methodAt present, the way to product white light with LED chips show in the table1.Tab.1 Preparation principle of“blue chip&YAG phosphor"The way of The white light

10、 production methodAdvantagesDisadvantagesCaN single grain Blue light LED +fluorescent materialSingle grain production method, low cost, electronic circuit, designed is simpleLuminous efficiency is low; of poor color; fluorescent material is not easy to find; limited phosphor coating, so thewhite lig

11、ht is not evenUV LED (375nm) + fluorescent materialPhosphor material is not easy to find, will enable the conversion efficiency higher than the YAG fluorescent material, light-emitting efficiency of space; good colorLuminous efficiency is low; packaging materials are easy to produce ultra-violet by

12、UV light ; limited phosphor coating, so thewhite light is not evenZnSe single grainBlue LED + ZnSe substrate Single grain product white light, low cost; low drive voltage (2.7); without the use of phosphorLuminous efficiency is 50% lower than CaN, about 8lM / W; short life, only 8000hDual-wave singl

13、e grainwhite lightSingle grain product white light,Other to be done to be doneMulti-grainGreen, blue & red, green and blue multi-color combinationsHigh luminous efficiency; can be dynamically adjusted color-temperature; of good color; natural colorThe needs of three grains, the grain of the need

14、 for individual electronic circuit design, high cost; poor of the close-up color; multi-color LED light-emitting efficiency is not evenAs a result of "blue light chips + YAG phosphor " have a white LED production method of the lowest cost, practicality's characteristic has become the m

15、ainstream products on the market. Therefore, the experiment chosen this method to product white LED.Key processes and technical measures Compared with the ordinary white-light LED, the high-power (W-class power) white LED has a higher power and more heat, therefore, in the packaging process, be cons

16、idered light, electricity, heat and other factors.Flip-chip technology Installed in the traditional way of LED chip package, because of P-type doped GaN difficulties, the current widely used in the preparation of P-type GaN metal transparent electrodes on the ways in which even the spread of current

17、 in order to achieve the purpose of light-emitting uniformity. P-type GaN on the transparent electrode metal to absorb 30% to 40% of a light, while n-type electrode and the lead will block some of the revealing light, which severely affect the chip LED light efficiency. In the manufacturing process,

18、 in order to improve light efficiency, generally transparent electrode metal thinning methods, so that in turn limits the current in the h-GaN surface evenly spread the impact of the product's reliability, constraint of the LED chip operating current . At the same time, such a structure is insta

19、lled through the PN junction calories derived sapphire substrates, sapphire is the thermal conductivity 35 W / (mK) (worse than the metal layers), a larger thermal resistance, resulting in bamboo core temperature rise, thus affecting the device the performance.This experiment, to take advanced flip

20、chip (flip-chip) technology, through the P-chip and n very very bottom of the production of ultrasonic gold wire leads to solder joint as the electrode structure and the outside of the Si chip on the production floor gold lead, to overcome the above-mentioned LED chips are mounted in a light efficie

21、ncy and the shortcomings of current constraints; chip PN junction from the heat generated by gold wire solder through a direct transfer to the Si substrate and heat sink, the heat transfer is far superior to the effect of Sapphire is mounted cooling structure; flip chip solder ball structure of the

22、gold wire to shorten the path, avoiding the chips installed in the traditional structure is a result of a long wire path phenomenon resulting from high fever; At the same time, the production of Si substrate reverse bias the PN junction, the realization of Si substrate and the Cu heat sink electrica

23、l isolation between; thus Increased product life LED, so that package greatly enhance the reliability.Optical design techniques1. To improve the refractive indexHigh-power white light LED chip refractive index of n = 2-4, much higher than the lens plays a role in the refractive index of packaging ma

24、terials (generally of the refractive index of epoxy resin at about 1.4-1.5). Therefore, when the light after the chip packaging materials, in a total reflection from the interface effect occurred, resulting in about 50% of the light reflection back to the chip itself, can not be effectively exported

25、 to become ultra-high brightness LED chips from low light efficiency underlying causes. How different materials will be among the internal refraction, reflection of light energy to be consumed in use, the design of optical systems is the key. Therefore, taking flip-chip technology to enhance the eff

26、iciency of the light at the same time, through on-chip light-emitting layer and Si increase the reflective layer between the bottom of the chip to heat sink side mirror processing methods, the rate of increase in light-emitting devices. In addition, flip-chip in the sapphire substrate surface and be

27、tween the combination of epoxy resin to increase the Si layer of plastic material as a buffer layer, to reduce stress due to thermal expansion caused by the phenomenon of delamination, chip out to improve and enhance the refractive index of light product reliability.2. Optimization of spherical opti

28、cal lensHigh-power LED devices at the top of the spherical lens design, LED light to improve the efficiency of market applications, also plays an important role. In the lens materials, select a high transmittance of the glass or acrylic and other synthetic materials to improve light efficiency; appl

29、ications in the market, according to lighting differences in optical design of the needs of the market demand for the company's largest spherical lens structure basis, taking into account a variety of other lens design. Thermal Packaging Technology Cooling for the power type LED devices is criti

30、cal, if not the current heat generated by the shed in time to maintain the PN junction to allow the junction temperature in the range will not be able to obtain a stable light output and maintenance of the normal life of the device. Thermal materials are usually used, although the best thermal condu

31、ctivity of Ag, but the high cost of the radiator not suitable for general-purpose. And Cu close to the thermal conductivity of Ag, and low cost compared with Ag. Although the thermal conductivity of Al is lower than Cu, but its integrated the lowest cost, is conducive to large-scale manufacturing. A

32、fter the experimental contrast, the approach is: to connect the chip part of the use of Cu or Ag-based matrix for the heat sink, and then the heat sink connected to the A1-based radiator, shed heat (or air-cooled heat transfer mode).This approach's advantages are: cost-effective full account of

33、the radiator, the radiator will be a different combination of features to achieve efficient heat dissipation, and the rationalization of cost control head. In addition, Cu-based heat sink to connect with the material between the chips is also very important to choose the general LED used as a connec

34、ting material silver plastic. However, due to the thermal resistance of plastic Ag high thermal conductivity in the 10-25 W / (mK), using Ag glue to connect the material, it means that people in between the chip and heat sink with a layer of thermal resistance.To this end, the introduction of a new

35、solid materials technology, welding technology that is a total of goods: The goods Sn films as tablets of welding and connecting material between the heat sink. Sn for the thermal conductivity of 67 W / (mK), its cooling effect and physical properties far superior to Ag glue, so to obtain a more ide

36、al thermal effects (thermal resistance coefficient of about 16( C / W).The production process and analyzes finallySplit - Blue light chip testing-The blue light chip sticks the piece-The vacuum dries-Eutectic welds-Wire solder YGA luminous powder-Vacuum drying-Point scattering medicinal preparation-

37、Vacuum drying-Fills the rubber-Vacuum drying-Drawing of patterns-Partly cuts-Test-All cuts-Long roasts-Separation-Packing-Warehousing Based on the above technology means 1w completed the development of high-power white LED to work with a advanced company, 1W high power white LED packages, compared t

38、o the parameters of performance, the laboratory developed 1w high power white light LED products, and its light-emitting efficiency close to the similar products abroad.Specific test results as shown in table 2.Tab.2 Comparison of measurement results with similar foreign products搜索I/mAThis experimen

39、t's 1W high power white LEDAdvanced company 1W high power white LED/W/V/W/V30065.413.493783.533Although high efficiency white light LED develops successfully, but to achieve and surpass the international advanced level, and realizes the batched production, but also has the following question to

40、need to solve: a. color uniformity is not highThis experiment selects “the blue light chip +YAG luminous powder” to have the white light LED manufacture method, because of using the manual spot rubber, will cause the luminous powder to be uneven distribution inevitably, causes in various directions,

41、 the yellow light colour blending allocated proportion not to be inconsistent blue, thus t influencing product's illumination luster and the uniformity, The white light color temperature change fluctuation which send out by it will be big, initiates the so-called facula effect. The chromaticity

42、uniform enhancement also depends on the new technological development.b. color rendering property index is insufficient The development of high-power white light LED products is the ultimate goal for general lighting, and therefore the color index is very important evaluation. This experiment using

43、blue, yellow blending methods produce white LED, so the performance of red is bad, causing part of the spectrum is not continuous, the spectrum can not be part of reflection to the human eye, which will feel the objects in the human eye color distortion. At present, the insider has been trying to us

44、e ultra-violet light-emitting chip make up RGB luminous powder, to fill the existing lack of red performance deficiencies of LED white light , but because ultraviolet luminous energy, extremely easy to destroy many seal materials, if works as when epoxy resin ultraviolet ray long-term illumination,

45、its structure in contains under the oxygen environment the very easy broken bond deterioration, produces the color machine group, causes the seal material yellow stain, then largely influence the white light LED brightness and white homogeneity. Therefore, the development of anti-ultraviolet transpa

46、rent materials as a package become enhances the colored index uniform new challenge. Coclusion In brief, high-power white light LED package is a multi-disciplinary involved, such as optical, electrical, thermal, materials and other study. From a certain perspective, high-power white light LED packag

47、e is not only a manufacturing technology, but also a constant innovation in the development of basic sciences. The need for good packaging technology of optical, electrical, thermal, materials and other physical nature of the understanding and use of the package to be introduced to update the struct

48、ural design and process technology.附錄B 大功率白光LED封裝工藝技術(shù)與研制與傳統(tǒng)的白熾燈、熒光燈照明相比，由于大功率白光LED具有顯著的節(jié)能、環(huán)保、使用壽命長等一系列不可比擬的優(yōu)勢，代表著新型綠色、環(huán)保照明的發(fā)展方向，正迅速進(jìn)軍照明領(lǐng)域。從1W大功率白光LED的封裝工藝技術(shù)出發(fā)，在分析比較了幾種產(chǎn)生白光LED方法的成本、性能的基礎(chǔ)上，最終選取性價(jià)比相對(duì)較高的“藍(lán)光芯片+YAG熒光粉”產(chǎn)生白光LED的制作方法。實(shí)踐證明，在提高大功率白光LED發(fā)光效率、均勻性和穩(wěn)定性等方面，還需要進(jìn)一步開發(fā)新材料，采用新工藝。引言LED是利用固體半導(dǎo)體芯片作為發(fā)光材料，采用電

49、場發(fā)光。作為光源，LED優(yōu)勢體現(xiàn)在節(jié)能、環(huán)保和長壽命三個(gè)方面。LED不依靠燈絲發(fā)熱來發(fā)光，能量轉(zhuǎn)化效率非常高，理論上只需要白熾燈10%的能耗，相比熒光燈，LED也可以達(dá)到50%的節(jié)能效果。專項(xiàng)調(diào)查表明，我國照明用電每年在3000億度以上，用LED取代全部白熾燈或部分取代熒光燈，可節(jié)省1/3的照明用電，意味著節(jié)約1000億度，相當(dāng)于一個(gè)總投資超過2000億三峽工程全年的發(fā)電量。用LED替代熒光燈，避免熒光燈竹破裂溢出汞的一次污染，而且制造LED的廢棄底板(鋁基覆銅板)可以回收重復(fù)利用。LED采用固體封裝，結(jié)構(gòu)牢固，壽命可達(dá)h。此外，LED還具有工作電壓低、耗電量小、光效高、響應(yīng)時(shí)間極短(ns級(jí))

50、、光色純、重量輕、體積小等一系列特性，發(fā)展突飛猛進(jìn)，尤其是大功率高亮度白光LED的發(fā)明，被業(yè)界稱為繼取火照明、愛迪生發(fā)明電燈之后的“照明領(lǐng)域的第三次革命”。白光LED的制作方法 目前，用LED芯片產(chǎn)生白光的方法見表(1)由于“藍(lán)光芯片+YAG熒光粉”產(chǎn)生白光LED的制作方法，其成本最低，實(shí)用性強(qiáng)，已經(jīng)成為目前市場產(chǎn)品的主流。因此，本實(shí)驗(yàn)選用該方法制作白光LED。表1白光LED產(chǎn)生方法的比較白光產(chǎn)生方式優(yōu)點(diǎn)缺點(diǎn)CaN單晶粒藍(lán)光LED+熒光材料單一晶粒產(chǎn)生白光,成本低,電子回路,設(shè)計(jì)簡單發(fā)光效率低；顯色性不佳；熒光材料不易尋找；限于熒光粉涂布，使白色光不夠均勻紫外光LED（375nm）+熒光材料熒

51、光粉材質(zhì)不容易尋找，可使轉(zhuǎn)換效率高于YAG的熒光材料，發(fā)光效率有提高空間；顯色性佳發(fā)光效率低；封裝材料被紫外光照射易產(chǎn)生老化；限于熒光粉涂布，使白色光不夠均勻ZnSe單晶粒藍(lán)光LED+ZnSe基板單粒產(chǎn)生白光，成本低；低驅(qū)動(dòng)電壓（2.7）；不需使用熒光粉發(fā)光效率較CaN低50%，約8lM/W；壽命短，僅8000h雙波長疊層單晶粒白光單晶粒產(chǎn)生白光；其他待研究待研究多晶粒綠、藍(lán)&紅、綠、藍(lán)多種色光組合發(fā)光效率較高；可動(dòng)態(tài)調(diào)整色溫；顯色性佳；顏色自然需要三顆晶粒，各晶粒需有個(gè)別的電子回路設(shè)計(jì)，成本高；近距離混色性不佳；多色LED發(fā)光效率不均關(guān)鍵工藝及技術(shù)措施相對(duì)于普通白光LED而言，大功率

52、(W級(jí)功率)白光LED具有更高的功率和更大的發(fā)熱量，因此，在封裝過程中，需要綜合考慮光、電、熱等多方面因素。倒裝芯片技術(shù)在傳統(tǒng)的正裝LED芯片封裝方式中，由于P型GaN摻雜困難，當(dāng)前普遍采用在P型GaN上制備金屬透明電極的方法，使電流均勻擴(kuò)散，以達(dá)到發(fā)光均勻性的目的。P型GaN上的金屬透明電極要吸收30%-40%的光，同時(shí)H型電極和引線也會(huì)遮擋部分光線的透出，這嚴(yán)重地影響著LED芯片的出光效率。在制造過程中，為改善出光效率，普遍采取減薄金屬透明電極的方法，這樣反過來又限制了電流在H型GaN表面的均勻擴(kuò)散，影響了產(chǎn)品的可靠性，制約著LED芯片的工作電流。同時(shí)，這種正裝結(jié)構(gòu)的PN結(jié)熱量通過藍(lán)寶石襯

53、底導(dǎo)出，藍(lán)寶石的導(dǎo)熱系數(shù)為35 W/ (mK)(比金屬層要差)，熱阻較大，導(dǎo)致竹芯溫度上升，從而影響器件的各項(xiàng)性能。本實(shí)驗(yàn)中，采取先進(jìn)的flip chip(倒裝芯片)技術(shù)，通過在芯片的P極和n極下方制作超聲波金絲球焊點(diǎn)作為電極的引出結(jié)構(gòu)，并在芯片外側(cè)的Si底板上制作金絲引線，克服了上述正裝LED芯片在出光效率與電流制約方面的缺點(diǎn);從芯片PN結(jié)產(chǎn)生的熱量通過金絲球焊點(diǎn)，直接傳導(dǎo)至Si基板和熱沉，其傳熱效果遠(yuǎn)優(yōu)于正裝藍(lán)寶石的散熱結(jié)構(gòu)；flip chip的金絲球焊結(jié)構(gòu)縮短了導(dǎo)線路徑，避免了在傳統(tǒng)正裝芯片結(jié)構(gòu)中因?qū)Ь€路徑較長而產(chǎn)生的高熱現(xiàn)象；同時(shí)，在Si基板上制作反向偏置的PN結(jié)，實(shí)現(xiàn)Si基板與Cu熱沉之間的電隔離;從而提高了LED產(chǎn)品壽命，使封裝的可靠性得到極大提升。光學(xué)設(shè)計(jì)技術(shù)1. 折射率的改善大功率白光LED的芯片折射率n= 2-4，遠(yuǎn)高于起著透鏡作用的封裝材料的折射率(一般環(huán)氧樹脂的折射率約在1.4-1.5)。因此，當(dāng)芯片發(fā)出的光經(jīng)過封裝材料時(shí)，在一者界面處發(fā)生全反射效應(yīng)，造成約50%的光線反射回芯片內(nèi)部，無法有效導(dǎo)出，成為超高亮度L