200541100 玖、發明說明 【發明所屬之技術領域】 本發明是有關於一種氮化鎵系發光二極體之形成方 法’且特別是一種具有導電基板之氮化鎵系發光二極體的 形成方法。 【先前技術】 發光二極體（Light Emitting Diode ; LED)因具有生產成 本低、結構簡單、低耗電、體積小以及安裝容易之優勢， 而大量運用於照明光源以及顯示器技術中。其中，又以類 屬氮化鎵系（Gallium Nitride-based ; GaN-based)的發光元 件’例如氮化鎵（GaN)藍光發光二極體，在近幾年的發光元 件市場中，甚受重視。 一般的氮化鎵系發光二極體，基於氮化鎵系膜層之結 晶品質的考量，大多選用藍寶石（sapphire)材質作為基板。 然而，由於藍寶石係為一絕緣材料，因此，使得元件中的 陽極電極與陰極電極須製作於藍寶·石基板的同一面上，而 導致電流傳送時’容易於陰極附近發生電流擁擠（current crowding)的效應，以致降低了光輸出的效率。同時，因為 藍寶石材質的散熱性不佳，亦會導致元件運作過熱的現象產 生，而降低了發光元件之運作效能。 為解決上述以藍寶石作為基材的缺失，故目前的氮化錄系 二極體之製作，係逐漸朝向基板轉移的技術發展，例如主要 是以雷射剝離（laser lift off)的技術，將藍寶石基材移除，並 200541100 以導電性材料取代藍f石基材，作為元件之承载基板。 然而，雷射剝離之進行，一般須由藍寶石基材之背面，整 面性地進行雷射光束之照射’故容易因雷射能量不均的現 象旦而導致二極體結構與藍寳石基材之接觸面獲得不均一的 熱量，尤其是分佈於雷射光束外圍之能量均勾度較差。且為 了使雷射《束確實照㈣二極體與藍f石基材之接觸面上的 所有位置’故難以避免雷射光束照射之重疊部分，而雷射光 束”、、射之重宜位置纟，易形成較高溫度，導致二極體上出現 溫度不均的梯度分佈。上述情形，皆會使基板之剝離效果不 佳’產生不平整的氮化鎵系二極體之剝離面，甚至造成元件 π刀膜層之剝;^或破裂，進而使元件受到損害，以及影響元 件後續之製作。 另外由於一般係於氮化鎵系二極體結構移轉至導電性^ 板之後，#進行元件單體定義a隔離餘刻㈣ati〇n etch^ 步驟’然而使用之導電性基板又大多為金屬㈣，如此q 導致於隔離蝕刻步驟中，甚&么思、一 J ^ ^ T產生金屬巧染的問題，而使製程ί」200541100 发明. Description of the invention [Technical field to which the invention belongs] The present invention relates to a method for forming a gallium nitride-based light-emitting diode ', and particularly to a method for forming a gallium nitride-based light-emitting diode with a conductive substrate. [Previous Technology] Light Emitting Diodes (LEDs) are widely used in lighting sources and display technologies because they have the advantages of low production cost, simple structure, low power consumption, small size, and easy installation. Among them, Gallium Nitride-based (GaN-based) light-emitting devices, such as gallium nitride (GaN) blue light-emitting diodes, have received much attention in the light-emitting device market in recent years. . Generally, GaN-based light-emitting diodes, based on the consideration of the crystal quality of the GaN-based film layer, mostly use sapphire as the substrate. However, because sapphire is an insulating material, the anode and cathode electrodes in the element must be made on the same side of the sapphire stone substrate, which causes current crowding (prone to current crowding near the cathode during current transmission). ) Effect, so that the efficiency of light output is reduced. At the same time, the poor heat dissipation of the sapphire material will also lead to overheating of the component operation, which will reduce the operating efficiency of the light-emitting component. In order to solve the above-mentioned lack of sapphire as the base material, the current production of nitrided diodes is a technology development that is gradually moving towards the substrate. For example, the sapphire is mainly based on laser lift off technology. The substrate was removed, and 200541100 replaced the blue f stone substrate with a conductive material as a carrier substrate for the component. However, the laser stripping generally requires the entire surface of the sapphire substrate to be irradiated with the laser beam. Therefore, it is easy to cause the diode structure and the sapphire substrate due to the phenomenon of uneven laser energy. The contact surface gets uneven heat, especially the uniformity of the energy distributed around the laser beam is poor. And in order to make the laser "the beam really shines at all positions on the contact surface of the diode and the blue f stone substrate ', it is difficult to avoid the overlapping part of the laser beam, and the laser beam", It is easy to form a higher temperature, which results in a gradient distribution of temperature unevenness on the diode. The above conditions will make the substrate peeling effect poor. 'Uneven peeling surface of the gallium nitride based diode will be produced, and even the component will be caused. The peeling of the π knife film layer; or cracking, which will damage the device and affect the subsequent production of the device. In addition, it is generally after the gallium nitride-based diode structure is transferred to the conductive plate, # for the device single The body definition a isolation etch atiati etch ^ step 'However, most of the conductive substrates used are metal 如此, so q in the isolation etch step, even & Mo Si, a J ^ ^ T produces metal cleverly dyed Problems while making the process
境以及元件特性受到危害。 除此之外，元件之亮度提升，亦是目前發光二極體技 術的主要發展趨勢’但是，現有之氮化鎵系發光元件的光 輸出強度，係完全取決於二極體本身的發光特⑭，對於向 几件下方射出的錢失部分，無法作有效地利帛，故對於 元件光輸出強度之提升仍有限。 【發明内容】 7 200541100 本發明之目的之一是在提供一種具導電基板之氮化鎵系 (GaN-based)發光二極體的形成方法，不但可以改善元件内的 電流分散情形，以提升發光二極體的光輸出效率，更利用對 元件之發光的有效利用，而大幅增強光輸出的強度，進而提 高元件的品質與亮度呈現。 裡民計之基板轉移技 本發明之另一目的，係在提供 術，將固定之雷射光束，針對定義完成之各元件單體進行照 射，以達成基板剝離效果，並同時維持元件品質。 根據本發明之上述目的，提出一種具導電基板之氮化鎵 系發光二極體的形成方法。依照本發明之方法係為先在基板 上形成複數個氮化鎵系發光元件，且各氮化鎵系發光元件之 間係藉由-溝渠予以分隔，而在溝渠中暴露出基板部分。其 中’溝渠之形成係由圖案化予以定義，例如採用活性離子蝕 刻或是感縣合式電㈣刻製程。至於每—氮化鎵系發光元 件内則包含1型氮化鎵系半導體層、—主動層以及一 p型 氮化鎵系半導體層，而基板係例如使用藍寶石材質，以達到 良好之氮化鎵系結晶品質。 · 接著，利用金屬接合的方；^ 脸 _ 鸯安口的万式，將一導電基材接合至氮化 紅系發光元件之上。違^雷其U曰，丨W , π 卞I上導電基材則例如選用矽、鋼、珅化鎵、 導電金屬或金屬合金等具導電特性之材質。 然後’利用一固定之雷如·止# , 化銨由基㈣面，對準各氮 化銥系發先7G件，分別依序進 ...^ Α 疋灯…射，而使基板與各氮化鎵 系毛光7L件之接觸面分離， 氣- 基板移除’並完整暴露出各 氮化鎵系毛光元件上之n型氮 乳化鎵系+導體層，則氮化鎵系 200541100 發光7L件係改由導電基板所承載。其中，使用之雷射光束係 控制為只足以完整照射到單一之氮化鎵系發光元件，而使雷 射光束之照射邊界恰好落在元件之間的溝渠中。 最後，再製作η型電極於各氮化鎵系發光元件之n型氮 化鎵系半導體層上。至於p f電極則可製作於導電基板上， 以達到元件内之垂直電流分佈。 另外，在上述製作過程中，於使用雷射照射之前，更可 以對各氮化鎵系發光元件，依序形成透明導電層與反射層於p l氮化鎵系半導體層之上，再進行後續之雷射剝離步驟。其 中，透明導電層係用以作為電流分散層，並同時具有高度光 穿透性，而反射層係對於氮化鎵系發光元件之發光具有高反 射率。 上述之η型氮化鎵系半導體層以及p型氮化鎵系半導體 層之材質，例如可為氮化鎵、氮化銦鎵或氮化鋁鎵。至於， 透明導電層係例如選用銦錫氧化物或銦辞氧化物材質。反射 層則選用對藍紫綠光具有高反射特性之金屬材質，例如銀、 紹、錄、把或銦。 - 、在本發明中，由於完成之氮化鎵系元件係為導電基材所 承載，因此，可將陽極電極直接製作於導電基材上，而有利 於元件内形成垂直電流分佈，以提高元件内電流傳遞分散的 效率並同4避免電流擁擠的現象產生，進而增進氮化嫁系 兀件的光輸出效率。另外，選用之導電基材通常亦具有優於 藍寶石的熱傳特性，因此，有助於增加元件的散熱性，而提 供發光元件操作時極佳的散熱效果，以保有元件的運作效能。 200541100 而應用本發明之雷射剝離 先以圖案化步驟定義出各元件 離製程，如此使用之雷射光束 行整面性地照射，而只要控制 即可順利達成基板分離之效果 同時，不論是雷射光束照 之照射邊界，皆可落在元件單 本身造成影響，因此，各元件 一之雷射能量，且不會有表面 不僅有利於基板之完整移除， 性’而不使元件受到損害，進 可靠度。 方法，係於雷射剝離 單體，然後再接著推/ 丹接者進行雷射剝 ，則不須對藍寶石基板背面進 為針對各元件單體進行照射， 〇Environment and component characteristics are endangered. In addition, the increase in the brightness of the device is also the main development trend of the current light-emitting diode technology. However, the light output intensity of existing gallium nitride-based light-emitting devices depends entirely on the light-emitting characteristics of the diode itself. As for the lost part of the money shot to the bottom, it cannot effectively benefit, so the improvement of the light output intensity of the component is still limited. [Summary of the Invention] 7 200541100 One of the objectives of the present invention is to provide a method for forming a GaN-based light emitting diode with a conductive substrate, which can not only improve the current dispersion in the device to improve light emission. The light output efficiency of the diode makes more effective use of the light emission of the element, which greatly enhances the intensity of the light output, thereby improving the quality and brightness of the element. Li Min Ji's substrate transfer technology Another object of the present invention is to provide a technology to irradiate a fixed laser beam to each component that has been defined in order to achieve a substrate peeling effect while maintaining component quality. According to the above object of the present invention, a method for forming a gallium nitride-based light emitting diode with a conductive substrate is proposed. According to the method of the present invention, a plurality of gallium nitride based light emitting elements are formed on a substrate, and each gallium nitride based light emitting element is separated by a trench, and the substrate portion is exposed in the trench. The formation of the 'ditch' is defined by patterning, for example, by active ion etching or electro-engraving. As for each-gallium nitride-based light-emitting element, a type 1 gallium nitride-based semiconductor layer, an active layer, and a p-type gallium nitride-based semiconductor layer are used, and the substrate is made of sapphire, for example, to achieve good gallium nitride. Department of crystal quality. · Next, use a metal-bonded square; ^ Face _ 鸯 Ankou Wanshi, a conductive substrate is bonded to the nitride red light-emitting device. According to Leiqi U, the conductive substrates on W, π, and I are made of materials such as silicon, steel, gallium halide, conductive metal, or metal alloy with conductive properties. Then, 'Using a fixed 雷 如 · 止 #, ammonium chloride from the base surface, aiming at the 7G pieces of each iridium nitride series, proceed in sequence ... ^ Α 疋 lights ... The contact surface of the gallium nitride-based Maoguang 7L is separated, the gas-substrate is removed, and the n-type nitrogen-emulsified gallium-based + conductor layer on each gallium nitride-based Maoguang device is completely exposed, and the gallium nitride-based 200541100 emits light. 7L parts are carried by conductive substrates. Among them, the laser beam used is controlled to illuminate only a single gallium nitride-based light emitting element completely, so that the irradiation boundary of the laser beam falls exactly in the trench between the elements. Finally, an n-type electrode is fabricated on the n-type gallium nitride-based semiconductor layer of each gallium nitride-based light-emitting device. As for the pf electrode, it can be fabricated on a conductive substrate to achieve vertical current distribution in the device. In addition, in the above manufacturing process, before using laser irradiation, a transparent conductive layer and a reflective layer can be sequentially formed on the gallium nitride-based semiconductor layer for each gallium nitride-based light-emitting element, and then subsequent Laser stripping step. Among them, the transparent conductive layer is used as a current dispersing layer, and at the same time has a high degree of light transmission, and the reflective layer has a high reflectivity for the light emission of the gallium nitride-based light-emitting element. The material of the n-type gallium nitride-based semiconductor layer and the p-type gallium nitride-based semiconductor layer may be, for example, gallium nitride, indium gallium nitride, or aluminum gallium nitride. As for the transparent conductive layer, for example, indium tin oxide or indium oxide is used. The reflective layer is made of a metal material that has high reflection characteristics for blue-violet-green light, such as silver, silver, aluminum, aluminum, or indium. -In the present invention, since the completed gallium nitride-based component is carried by a conductive substrate, the anode electrode can be directly fabricated on the conductive substrate, which is beneficial to the formation of a vertical current distribution in the component to improve the component. The efficiency of the internal current transmission dispersion is the same as that of 4 to avoid the phenomenon of current crowding, thereby improving the light output efficiency of the nitrided system. In addition, the selected conductive substrate usually has better heat transfer characteristics than sapphire. Therefore, it helps to increase the heat dissipation of the device, and provides excellent heat dissipation effect during the operation of the light-emitting device to maintain the operating performance of the device. 200541100 The laser stripping applying the present invention first defines the separation process of each element by a patterning step. The laser beam used in this way is irradiated on the entire surface, and the effect of substrate separation can be smoothly achieved as long as it is controlled. The irradiation boundary of the light beam can fall on the component sheet itself to affect it. Therefore, the laser energy of each component and no surface will not only facilitate the complete removal of the substrate, but also will not damage the component. Reliability. The method is based on the laser stripping of the monomer, and then the laser stripping is carried out by the pusher / danser. Then, it is not necessary to irradiate the back of the sapphire substrate for each element. 〇
射之重疊1立罟，4、e I 且位置，或是雷射光束 體之間的溝渠處，而不對元件 單體之剝離面皆得以接收到均 溫度分佈不均的現象。如此， 更能保有元件單體之結構完整 而提昇產品之製造良率與元件 除此之外，本發明更利用反射層的形成，而使元件内向 下射出的光，能藉由反射層的反射作用，而提供成為向上輸 出的光源’以對元件内之發光作更有效地利用，進而增加元 件可達成的光輸出強度。同時，再配合上透明導電層，一方 面以有助於電流之分散，另一方面則使氮化鎵元件内之發 光’可大量穿透透明導電層，而傳送至反射層上，供反射層 進行光反射，以增加元件實際可擷取的反射光量，使更有利 於光輸出強度之大幅提升，進而提高元件之亮度呈現。 【實施方式】 本發明係提供一種氮化鎵系（GaN-based)發光二極體之形 成方法，結合隔離#刻（isolation etching)與雷射剝離（laser lift ίο 200541100 off)製程，以良好控制雷射剝離之進行，而達到基板轉移之目 的，形成具導電基板之氮化鎵發光二極體結構，有利於元件 内部產生垂直電流分佈。另外，並利用反射層之設置，以提 高元件之光輸出強度。以下將以實施例對本發明之方法加以 詳細說明。 實施例 本發明揭露了一種具導電基板之氮化鎵（GaN)發光二極 體的形成方法。依序參照第1A〜1F圖，第1A〜1F圖係為依照 本發明較佳實施例之一種氮化鎵發光二極體形成方法的流程 剖面示意圖。 在第1A圖中，首先在基板1〇〇上製作氮化鎵二極體結 構，係為分別依序形成一 n型氮化鎵半導體層1 〇4，一具有多 層量子井（Multi-Quantum Well)結構之發光主動層1〇6，以及 一 P型氮化鎵半導體層108於基板100之上。其中，基板1〇〇 例如選用藍寶石（sapphire)材質，以獲得結晶品質良好的氮化 鎵半導體層。 - 在P型氮化鎵半導體層108之上，形成一蝕刻保護層 no，並對蝕刻保護層110進行圖案化，以定義出開口 Ul。 接著，利用圖形定義後的蝕刻保護層110作為蝕刻罩幕（hard mask)，由開口 111的位置，往下進行隔離蝕刻步驟，以定義 出氮化鎵二極體之元件單體，且於隔離蝕刻進行完成後，將 餘刻保護層11 〇移除，如第i B圖所示。其中，蝕刻保護層i J 〇 係選用對氮化鎵具有高蝕刻選擇比之材質，例如較佳可為二 11 200541100 氧化碎（Si〇2)，以於隔離姓刻步驟進行時，作為餘刻罩幕，並 避免餘刻保護層1 10下方之氮化鎵結構遭受蝕刻之傷害。 在第1B圖中，溝渠112係為隔離蝕刻進行後，形成於各 氮化鎵二極體之元件單體間的通道，且溝渠112中完整暴露 出基板100，以區隔各元件單體之電性。上述用以形成溝渠 112之隔離蝕刻步驟，則例如可採用活性離子蝕刻The overlapping of the shots is 1 ridge, 4, e I, and the position, or the trench between the laser beam bodies, and the non-uniform temperature distribution of the component alone can be received. In this way, the structural integrity of the element alone can be maintained and the manufacturing yield and components of the product can be improved. In addition, the present invention makes more use of the formation of a reflective layer, so that the light emitted downward from the element can be reflected by the reflective layer. Function, and provide a light source that becomes an upward output to make more effective use of the light emission in the element, thereby increasing the light output intensity that the element can achieve. At the same time, with the transparent conductive layer, on the one hand, it helps to disperse the current, and on the other hand, the light emission in the gallium nitride element can penetrate the transparent conductive layer in large quantities and be transmitted to the reflective layer for the reflective layer. Light reflection is performed to increase the amount of reflected light that can be actually captured by the component, which is more conducive to a substantial increase in light output intensity, and thus improves the brightness presentation of the component. [Embodiment] The present invention provides a method for forming a gallium nitride-based (GaN-based) light-emitting diode, which combines an isolation etching process and a laser lift (200541100 off) process for good control. The laser stripping is performed to achieve the purpose of substrate transfer, forming a gallium nitride light emitting diode structure with a conductive substrate, which is beneficial to the vertical current distribution inside the device. In addition, the arrangement of the reflective layer is used to increase the light output intensity of the device. Hereinafter, the method of the present invention will be described in detail with examples. Embodiments The present invention discloses a method for forming a gallium nitride (GaN) light emitting diode with a conductive substrate. Figures 1A to 1F are sequentially referred to, and Figures 1A to 1F are schematic cross-sectional views showing the flow of a method for forming a gallium nitride light emitting diode according to a preferred embodiment of the present invention. In FIG. 1A, a gallium nitride diode structure is first fabricated on a substrate 100, which is to sequentially form an n-type gallium nitride semiconductor layer 104 and a multi-quantum well (Multi-Quantum Well). A light-emitting active layer 106 of a) structure, and a P-type gallium nitride semiconductor layer 108 on the substrate 100. The substrate 100 is made of sapphire, for example, to obtain a gallium nitride semiconductor layer with good crystal quality. -An etch protection layer no is formed on the P-type GaN semiconductor layer 108, and the etch protection layer 110 is patterned to define an opening Ul. Then, the etching protection layer 110 defined by the pattern is used as an etching mask (hard mask), and an isolation etching step is performed from the position of the opening 111 to define a single element of the gallium nitride diode and isolate the element. After the etching is completed, the remaining protective layer 110 is removed, as shown in FIG. IB. Among them, the etching protection layer i J 〇 is made of a material that has a high etching selection ratio to gallium nitride. For example, it may be preferably 2 11 200541100 oxide chip (Si〇2), which is used as the remaining time when the isolation step is performed. Cover the screen and prevent the gallium nitride structure under the protective layer 1 10 from being damaged by etching. In FIG. 1B, the trench 112 is a channel formed between the individual elements of each gallium nitride diode after the isolation etching is performed, and the substrate 100 is completely exposed in the trench 112 to separate the individual elements from each other. Electricity. In the above-mentioned isolation etching step for forming the trench 112, for example, active ion etching may be used.
Ion Etching; RIE)或是感應耦合式電漿（Inductively c〇upledIon Etching; RIE) or inductively coupled plasma
Plasma ; ICP)蝕刻技術，以對氮化鎵二極體結構進行蝕刻。 接著’參照第1 C圖，再依序形成透明導電層丨丨4與反射 層116於各氮化鎵元件單體上，其中，透明導電層114係用以 與P型氮化鎵半導體層1〇8形成良好之歐姆接觸（〇hmic contact)，以及作為電流分散層（current- spreading lay^)，提 供電流分散作用，同時，透明導電層114具有之高度光穿透 特性，可使氮化鎵之發光大量穿透至反射層116之上，以供 反射層116進行反射。透明導電層114的材質例如可選用錮錫 氧化物（Indium Tin 0xide; IT〇)或銦鋅氧化物（Indium_zi加 Oxxde ; IZO)。另外，反射層116則係選用對於紫藍綠光波長 範圍之發光具有高反射率的材質，例如可為銀（Ag)、鋁（A1)、 鎳（Ni)、鈀（Pd)或等金屬材質。 在反射層116形成之後，於反射層116的表面製作一金屬 接合層117,以與一導電基材12〇上的金屬接合層119相接 觸，藉由金屬接合（metal bonding)的方式，使導電基材12〇形 成於反射層116之上方，與製作於基板1〇〇上的氮化鎵元件 單體相結合。其中，金屬接合層117的材質例如可為鎳、金 12 200541100 (Au)、銅（Cu)、鈀、銦（in)或錫（Sn)，而金屬接合層119的材 質則例如可為鎳、金、銅、鈀、氮化钽（TaN)或氮化鈦（TiN)。 金屬接合層117與金屬接合層11 9係以金屬鍵結的型式進行接 合，而達到將導電基材120連接於反射層116之上的目的。 同時，為了承受金屬接合之高溫操作過程，亦可將上述之透 明導電層114的材質，特別選用鎢（w)、鈀或鉑（pt)等耐熱金 屬或耐熱金屬合金。另外，導電基材12〇係選用具有導電性 的材質，例如可為矽（Si)、銅、砷化鎵（GaAs)、導電金屬或金 屬合金。 然後，參照第1D圖，使用雷射光束13〇照射，以進行雷 射剝離（laser lift off)製程，利用條件均一之雷射光束13〇，由 基板100之背面，對準已定義好之各氮化鎵元件單體，分別 予以照射，使雷射光束130穿透基板1〇〇，並被n型氮化鎵半 導體層104所吸收，產生氮化鎵的分解現象，而由n型氮化 鎵半導體g 1G4與基板⑽之界面，形成基板丨⑼與η型氮 化蘇半導體層1 〇4的分離狀態，以將基板} 移除。 其中，照射於各元件單體上之雷.射光束13〇，係具有相同 能量與相同光束尺寸（beam size)l4〇，並將光束尺寸14〇控制 為與各元件單體尺寸接近，但略大於各元件單體之尺寸，以 使各7L件單體能完整位在雷射光束13〇之照射範圍中，例如 疋件單體尺寸為0.3mm*0.3mm時，則控制光束尺寸14〇較佳 約為〇.32mm*0.32mm。如此，雷射光束13〇的照射邊界，將 落在各元件單體之外，且不論是雷射光束13〇照射之重疊位 置，或是雷射光束130之照射邊界部分，皆能恰好落在各元 13 200541100 件單體之間的溝渠112中，而不致於使各元件單體上的^型 氮4化鎵半導體層104，產生溫度不均之溫度梯度分布現象。 因此’各元件單體上之η型氮化鎵半導體層1 04所接收 到的雷射能量，係來自於雷射光束13〇内能量分布較為均勻 的中心部分，故有助於各元件單體之η型氮化鎵半導體層1 04 與基板100的接觸面，皆獲得均一的雷射能量。同時，又因 為/、須針對有元件單體存在的位置予以照射，即可達到分離 基板1 00之目的’故可有效避免雷射照射出現重疊部分，甚 至減少雷射光束實際使用之次數。 經由雷射剝離製程，將基板i 〇〇移除之後，即完成基板 轉移之目的，形成如第1E圖所示的下方p型之氮化鎵發光二 極體結構，P型氮化鎵半導體層1〇8位於η型氮化鎵半導體層 104之下方，且各疋件單體係承載於具有導電特性之導電基材 120之上。Plasma; ICP) etching technology to etch the gallium nitride diode structure. Next, referring to FIG. 1C, a transparent conductive layer 4 and a reflective layer 116 are sequentially formed on each gallium nitride element. Among them, the transparent conductive layer 114 is used to communicate with the P-type GaN semiconductor layer 1 〇8 form a good ohmic contact (〇hmic contact), and as a current-spreading layer (current- spreading lay ^), to provide current spreading effect, at the same time, the transparent conductive layer 114 has a high light transmission characteristics, can make gallium nitride A large amount of luminescence penetrates above the reflective layer 116 for reflection by the reflective layer 116. The material of the transparent conductive layer 114 can be, for example, osmium tin oxide (Indium Tin Oxide; IT0) or indium zinc oxide (Indium_zi plus Oxxde; IZO). In addition, the reflective layer 116 is made of a material that has high reflectivity for light emission in the wavelength range of purple, blue, and green, and can be silver (Ag), aluminum (A1), nickel (Ni), palladium (Pd), or other metal materials. . After the reflective layer 116 is formed, a metal bonding layer 117 is formed on the surface of the reflective layer 116 to be in contact with the metal bonding layer 119 on a conductive substrate 120, and conductive by metal bonding. The base material 120 is formed above the reflective layer 116 and is combined with a gallium nitride element monomer fabricated on the substrate 100. The material of the metal bonding layer 117 may be nickel, gold 12 200541100 (Au), copper (Cu), palladium, indium or tin (Sn), and the material of the metal bonding layer 119 may be nickel, Gold, copper, palladium, tantalum nitride (TaN) or titanium nitride (TiN). The metal bonding layer 117 and the metal bonding layer 119 are bonded in a metal bonding type to achieve the purpose of connecting the conductive substrate 120 to the reflective layer 116. At the same time, in order to withstand the high temperature operation process of metal bonding, the transparent conductive layer 114 may be made of a heat-resistant metal or heat-resistant metal alloy such as tungsten (w), palladium, or platinum (pt). In addition, the conductive substrate 120 is made of a conductive material, and may be, for example, silicon (Si), copper, gallium arsenide (GaAs), a conductive metal, or a metal alloy. Then, referring to FIG. 1D, the laser beam 130 is irradiated to perform a laser lift off process, and the laser beam 13 which is uniform in condition is used to align the defined ones from the back of the substrate 100. The gallium nitride element is irradiated separately, so that the laser beam 130 penetrates the substrate 100, and is absorbed by the n-type gallium nitride semiconductor layer 104, resulting in the decomposition of gallium nitride, and the n-type nitride The interface between the gallium semiconductor g 1G4 and the substrate 形成 forms a separated state between the substrate ⑼ and the n-type nitride semiconductor semiconductor layer 104 to remove the substrate}. Among them, the laser beam 13 irradiated on the individual elements has the same energy and the same beam size 14, and the beam size 14 is controlled to be close to the individual element sizes, but slightly It is larger than the size of each element, so that each 7L unit can be completely located in the irradiation range of 13 °. For example, when the size of the unit is 0.3mm * 0.3mm, the beam size is controlled to 14 °. It is preferably about 0.32mm * 0.32mm. In this way, the irradiation boundary of the laser beam 130 will fall outside each element, and regardless of the overlapping position of the laser beam 130 or the irradiation boundary portion of the laser beam 130, it can fall exactly on In each of the trenches 112 200541100, the temperature gradient distribution phenomenon of uneven temperature in the gallium nitride gallium nitride semiconductor layer 104 on each element is not caused. Therefore, the laser energy received by the n-type gallium nitride semiconductor layer 104 on each of the individual elements comes from the central part of the laser beam with a relatively uniform energy distribution, so it contributes to the individual elements. The contact surfaces of the n-type gallium nitride semiconductor layer 104 and the substrate 100 all obtain uniform laser energy. At the same time, because it is necessary to irradiate the location where there is a single element, the purpose of separating the substrate 100 can be achieved. Therefore, it is possible to effectively avoid overlapping portions of the laser irradiation, and even reduce the number of times the laser beam is actually used. After the substrate is removed through the laser lift-off process, the purpose of the substrate transfer is completed, and a p-type GaN light emitting diode structure and a P-type GaN semiconductor layer are formed as shown in FIG. 1E. 108 is located below the n-type gallium nitride semiconductor layer 104, and each component is supported on a conductive substrate 120 having conductive characteristics.
最後’參照、帛1F «，再分別於各元件單體上製造陰極電 極122’以完成氮化鎵發光元件之製作，至於陽極電極則可另 外裝設於導電基材12〇表面上的任何位置。 利用導電基材120具有之導雷牲从 π & β _ ^ , <导電特性，可使陽極電極直指 製作於導電基材120之下方，而佶条儿於交 ^ 卜万而使虱化鎵發光元件内之電淡 、呈現垂直電流之分佈，避免電流擁擠效應，以提高電涕 刀政之成效，進而有效提升元件之光輸出效率。 另外，更利用反射層丨丨6的形士 ^ ^ 咚τ 加八士 i 的幵7成’而使元件内的發光， 除了一部份直接向上輸出之外， Μ , . ^ ^ 4 卜另一部份向下發出的光，則 籍由反射層的反射作用，而接 供成為向上輸出的光源，使元 14 200541100 件内的發光能被有效地利用，以增加元件可達成的光輸出強 度。同時，配合上透明導電層114, 一方面以有助於電流之分 散，另一方面則使氮化鎵元件内之發光，可大量穿透透明導 電層，而傳送至反射層上，供反射層進行光反射，以增加元 件實際可擷取的反射光量，進而更有利於光輸出強度之提升。 除了上述之結構外，亦可再於陰極電極122與n型氮化 鎵半導體I 104之間，設置一透明氧化物導電層，例如銦錫 氧化物或銦鋅氧化物’具有近似η型之導電特性，以使陰極 電極122上的電流能均勻分散至u氮化鎵半導㈣1〇4之 中’而有利於大面積之功率元件（p〇wer chip)的製作，進而提 高元件尺寸定義之彈性度。 製程， 元件内 率，並 的光輸 離製程 單體， ’則不 為針對 射光束 對元件 收到均 如此， 根據上述本發明之實施例的方法，應用雷射剝離 可將原本的絕緣性基板，轉換為導電性基板，以利於 形成垂直電流分佈’而提高元件内電流傳遞分散的效 同時避免電流擁擠的現象產生，進而增進氣化嫁元件 出效率。而應用本發明之雷射剝離製程，係於雷射剝 進行前’ t以隔離蝕刻之圖案化步驟，定義出各元件 然後再接著進行雷射剝離製程，如此使用之雷射光束 須由藍寶石基板背面進行整面性地照射，巾只要控制 各元件單體進行照射，即可順利達成基板分離之效果 同時’不論是雷射光束照射之重疊位置，或是雷 之照射邊界’皆可落在元件單體之間的溝渠處，而不 本身造成影響’因1各元件單體之剝離面皆得以接 -之雷射能量，且不會有表面溫度分佈不均的現象。 15 200541100 不僅有利於藍寶石基板之完整移除，更能保有元件單體之結 構完整性，而不使元件受到損害，進而提昇產品之製造良率 與元件可靠度。 除此之外，本發明更利用反射層與透明導電層之結合， 以同時提高電流分散的效果，以及對氮化鎵元件之發光的有 效利用’使氮化鎵元件的光輸出強度得以大幅增加，進而提 高元件之亮度呈現。 本發明不只侷限於使用在氮化鎵發光二極體的技術上， 其他所有屬於氮化鎵系發光二極體元件之製作，例如氮化銦 鎵（InGaN)發光二極體或氮化鋁鎵（A1GaN)紫外光發光二極 體，亦可藉由本發明之方法製作，而大幅提升產品的特性。 雖然本發明已以實施例揭露如上，然其並非用以限定本 發明，任何熟習此技藝者，在不脫離本發明之精神和範圍内， 當可作各種之更動與修飾，因此本發明之保護範圍當視後附 之申請專利範圍所界定者為準。 【圖式簡單說明】 _ 為讓本發明之上述特徵、方法、目的及優點能更明顯易 懂，配合所附圖式，加以說明如下： 第1A〜1F圖係為依照本發明較佳實施例之一種氮化鎵發 光·一極體形成方法的流程剖面示意圖。 【元件代表符號簡單說明】 1 〇 〇 :基板 200541100 104、108:氮化鎵半導體層 1 0 6 :主動層 1 1 1 ··開口 1 1 4 :透明導電層 1 1 7、1 1 9 ··金屬接合層 1 2 2 :電極 1 4 0 :光束尺寸 1 1 0 :蝕刻保護層 1 1 2 :溝渠 1 1 6 :反射層 1 2 0 :導電基材 1 3 0 :雷射光束Finally, 'reference, 帛 1F «, and then manufacture the cathode electrode 122 on each element individually to complete the production of gallium nitride light-emitting elements. As for the anode electrode, it can be additionally installed at any position on the surface of the conductive substrate 12 . Using the conductive properties of the conductive substrate 120 from π & β _ ^, < conductive properties, the anode electrode can be made directly below the conductive substrate 120, and the purlins can be made at the same time. The electric light in the gallium lice light-emitting element presents a vertical current distribution, avoiding the current crowding effect, in order to improve the effectiveness of the electric knife, and then effectively improve the light output efficiency of the element. In addition, the shape of the reflective layer 丨 丨 6 is also used ^^ 咚 τ plus 幵 70% of the eighth i to make the light inside the element, except that a part directly outputs upward, Μ,. ^ ^ 4 A part of the light emitted downward is reflected by the reflection layer, and is used as the light source for upward output, so that the light emission in the element 14 200541100 can be effectively used to increase the light output intensity that the component can achieve. . At the same time, in conjunction with the transparent conductive layer 114, on the one hand, it helps to disperse the current, and on the other hand, it makes the gallium nitride element emit light, which can penetrate the transparent conductive layer in large quantities and be transmitted to the reflective layer for the reflective layer. Perform light reflection to increase the amount of reflected light that can be actually captured by the component, which is more conducive to the improvement of light output intensity. In addition to the structure described above, a transparent oxide conductive layer, such as indium tin oxide or indium zinc oxide, may be provided between the cathode electrode 122 and the n-type gallium nitride semiconductor I 104. Characteristics, so that the current on the cathode electrode 122 can be uniformly dispersed in the uGaN gallium semiconductors 104, which is beneficial to the production of large-area power devices (power chips), thereby improving the flexibility of the definition of the device size degree. The manufacturing process, the internal rate of the element, and the light transmission from the manufacturing process are not the same for receiving the element for the beam. According to the method of the embodiment of the present invention described above, the original insulating substrate can be removed by applying laser peeling. It is converted into a conductive substrate to facilitate the formation of a vertical current distribution, thereby improving the efficiency of current transfer and dispersion in the element while avoiding the phenomenon of current crowding, thereby improving the efficiency of gasification of the element. The application of the laser stripping process of the present invention is a patterning step of isolation etching before the laser stripping is performed, defining each component and then performing the laser stripping process. The laser beam used in this way must be a sapphire substrate The whole surface is irradiated on the back surface. As long as the individual components are controlled to irradiate, the substrate separation effect can be achieved smoothly. At the same time, 'regardless of the overlapping position of the laser beam irradiation or the irradiation boundary of the lightning', it can fall on the element At the trench between the monomers, it does not affect the laser energy because the peeling surfaces of the individual component monomers can be connected, and there is no uneven surface temperature distribution. 15 200541100 Not only facilitates the complete removal of the sapphire substrate, but also maintains the structural integrity of the component monomer without damaging the component, thereby improving the product yield and component reliability. In addition, the present invention further utilizes the combination of a reflective layer and a transparent conductive layer to simultaneously improve the effect of current dispersion and the effective use of the light emission of the gallium nitride device, so that the light output intensity of the gallium nitride device can be greatly increased. , Thereby improving the brightness of the component. The present invention is not limited to the technology used in gallium nitride light-emitting diodes, all other gallium nitride-based light-emitting diode devices are manufactured, such as indium gallium nitride (InGaN) light-emitting diodes or aluminum gallium nitride. (A1GaN) ultraviolet light-emitting diodes can also be produced by the method of the present invention, which greatly improves the characteristics of the product. Although the present invention has been disclosed as above by way of examples, it is not intended to limit the present invention. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection of the present invention The scope shall be determined by the scope of the attached patent application. [Brief description of the drawings] _ In order to make the above features, methods, objectives and advantages of the present invention more comprehensible, in conjunction with the accompanying drawings, the description is as follows: Figures 1A to 1F are the preferred embodiments according to the present invention A schematic flow cross-sectional view of a method for forming a gallium nitride light-emitting monopole. [Simple description of element representative symbols] 1 00: substrate 200541100 104, 108: gallium nitride semiconductor layer 1 06: active layer 1 1 1 ·· opening 1 1 4: transparent conductive layer 1 1 7, 1 1 9 ·· Metal bonding layer 1 2 2: electrode 1 4 0: beam size 1 1 0: etching protection layer 1 1 2: trench 1 1 6: reflective layer 1 2 0: conductive substrate 1 3 0: laser beam
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