201145594 六、發明說明： 【發明所屬之技術領域】 本發明係提供一種氮化鎵發光二極體及其製造方法，尤 指其技術上提供一種藉由基板底部蝕刻孔洞與蒸鍍反色金 屬層，與電鍵銅填滿孔洞，而達到亮度進一步提昇之氮化 鎵發光二極體及其製造方法。 【先前技術】 一般之氮化鎵發光二極體製造方法分成以下步驟： 步驟一，試片之研磨與清洗：成長於藍寶石（sapphire) 基板的GaN LED試片，先使用研磨的方式將藍寶石 (sapphire)基板磨薄至150μιη，經過清洗，使用丙酮去除油 脂，倒入燒杯中後將磊晶片放入，並將整個燒杯放入超音 波震洗機震洗，接著再使用異丙醇以相同的方法放入超音 波震洗，為了去除殘餘的丙酮，最後再使用D·丨震 洗，震洗完後用氮氣吹乾即可完成初步清洗； 步驟二，平台（mesa)蝕刻：於正面磊晶層成長二氧化 矽（Si〇2)，以曝光微影技術定義出平台之圖案，並且以氧化 物触刻液钮刻出平台.圖％，再利用感應式麵合電㈣刻機 (inductivity coupied piasma，icp)蝕刻氮化鎵磊晶結構 層’蝕刻至㈣n型氮化鎵表面為止，最後再使用氧化物 蝕刻液將二氧化矽移除，即完成平台蝕刻； 步驟三，透明導電層以及電極製作：平台蝕刻完之後 3 201145594 ，接下來便是用電子束蒸鍍機在真空狀態下，蒸鍍銦錫氧 化物（indium tin oxide, ΙΤ0)，並使用熱退火爐管退火之 後再使用曝光微影技術定義出所需要的透明電極，並且以 ΙΤ0蝕刻液蝕刻掉不需要的透明電極，再以去離子水清洗試 片後再吹乾。在ρ、η電極的製程上使用曝光微影技術先定 義出電極區域，再以電子束蒸鍍機蒸鍍Ν型電極，接著再 把試片放入丙酮中浸泡，並以f (撥離）方式留下電 極區域之金屬’最後再使用熱退火爐管退火，即可完成電 極製作。 透過上述製造方法所製造之氮化鎵發光二極體，其結 構如第十五圖所示’由下而上主要依序包括一藍寶石基板 (30)、一無摻雜氮化鎵系層（31)、一 η型摻雜氮化鎵系層 (32)、一發光層（MQW)(33)、一 ρ型摻雜氮化鎵系層（34); 另可形成一透明導電層（35)於該p型摻雜氮化鎵系層（34) 之上，及一 p型金屬電極（36)位於該透明導電層（35)之上 ;並利用蝕刻移除部份p型摻雜氮化鎵系層（34)、部分發 光層（33)後，於露出的η型摻雜氮化鎵系層（32)上可形成 一 η型金屬電極（37)。 惟，其上述習知之氮化鎵發光二極體，其發光時光線 從發光層（33)四面八方射出’而部分光線射向藍寶石基板 (30)後，就會由藍寶石基板（30)底部直接射出，而無法被 充分利用到。 201145594 是以，針對上述習知結構 厅存在之問題點，如何開發 —種更具理想實用性之創新社 冓’貫消費者所殷切企盼， 亦係相關業者須努力研發突 % <目標及方向。 有鑑於此’發明人本於 、>年從事相關產品之製造開發 與設計經驗’針對上述之目 > 知’坪加設計與審慎評估後， 終得一確具實用性之本發明。 【發明内容】 之氮化鎵發光二極體在發 ’而部分射向藍寶石基板 出而無法被充分利用到。 欲解決之技術問題點：習知 光時光線從發光層四面八方射出 的光線，會由藍寶石基板底部射 解決問題之技術特點：為改善上述之問題，本發明提 供-種具背面反射鏡與散熱層之氮化鎵發光二極體，其由 下而上依序包括-藍寶石基板、—無摻雜I化鎵系層、一 n Ρ型摻雜氮化鎵系層， 型推雜鼠化嫁系層、一發光層、 其特徵在於：該藍寶石基板底部蝕刻形成數内凹的孔洞 並蒸鍍形成一層反射金屬層於該藍寶石基板底部與數該孔 洞内壁，藉此該發光層往下發出之光線可透過該反射金屬 層而往上反射’而大幅增加該氮化鎵發光二極體的發光亮 度。 本發明另提供如上述之具背面反射鏡與散熱層之氮化 鎵發光二極體之製造方法’係於試片的藍寶石基板底部银 刻形成數内凹的孔洞，並蒸鍍形成一層反射金屬層於該藍 201145594 寶石基板底部與數該孔洞内壁，藉此該發光層往下發出之 光線可透過該反射金屬層而往上反射，而大幅增加該氮化 鎵發光二極體的發光亮度，其中，並可電鍍形成一銅塊填 滿該蝕刻孔洞，藉此減少熱效應產生，進一步提昇發光效 率 0 對照先前技術之功效：本發明藉由基板底部蝕刻形成 數内凹的孔洞與蒸鍍的反射金屬層，可將朝底部射出的光 線反射回去，而達到發光亮度的提昇，並藉由電鍍銅填滿 該孔洞，減少熱效應產生，更進一步提昇發光效率。 有關本發明所採用之技術、手段及其功效，茲舉一較 佳實施例並配合圖式詳細說明於后，相信本發明上述之目 的、構造及特徵’當可由之得一深入而具體的瞭解。 【實施方式】 參閱第一至第五圖所示’本發明係提供一種具背面反 射鏡與散熱層之氮化鎵發光二極體，其由下而上依序包括 一藍寶石基板（10)、一無摻雜氮化鎵系層（丨丨）、一 η型推 雜氮化鎵系層（12)、一發光層（MQW)(13)、一 ρ型換雜氮化 鎵系層（14)，其特徵在於： 該藍寶石基板（1 0 )底部姓刻形成數内凹的孔洞（1 〇 1 ) ’並蒸鍍形成一層反射金屬層（102)於該藍寶石基板（1〇)底 部與數該孔洞（101)内壁，藉此該發光層（13)往下發出之光 線可透過該反射金屬層（1 0 2 )而往上反射，而大幅增加該氮 201145594 化鎵發光二極體的發光亮度。 其中，於蒸鍍形成一層反射金屬層（1 〇 2 )後的數該孔洞 (101)内，可電鍍形成一銅塊（103)填滿該孔洞（1〇1)，藉此 減少熱效應。 其中’該P型摻雜氮化鎵系層（14)上可堆疊一透光導 電層（15) ’該透光導電層（15)為蒸鍍銦錫氧化物（indium tin oxide,ITO)。 其中，该透光導電層（15)上可形成一 p型金屬電極（16) ’ s亥p型金屬電極（16)可為Cr/Au電極。 其中，該η型摻雜氮化鎵系層（12)之表面上可形成η 型金屬電極（17)，該η型金屬電極（17)可為Cr/Au電極。 其中，藍寶石基板（10)底部蝕刻形成的孔洞（1〇1)間隔 位置不同，Μ寶石基板（10)切割出來的形狀也會有所不同 ，藍寶石基板(1。)經切割後可形成略呈梯形的藍寶石基板 (⑻（請參閱第三及第四圖）或呈内凹—孔洞（m)之藍寶 ㈣而本實施例使用耗 刻的方式進行孔洞(101)的姓刻，所以該孔洞(ι〇ι)底部會 呈平面狀。 請參閱第六圖，本發明之製造方法依序如. 化鎵發光二極體（GaN LED)之試片； B.於該試片的兩面各形成一异_ 喈—巩化矽（Si〇2) A.提供-清洗過之試片，該試基板上成長—氮 薄膜 201145594 c.使用曝光微影技術於基板底面製作出預備姓刻孔洞 之圖案’然後使用氧化物I虫刻液（buffer 〇xide etching, ΒΟΕ,ΗΡ.Η2〇-1.6)Ί虫刻，而形成數個内凹的触刻孔 洞； D. 於s玄氮化紅發光一極體上’對該試片進行平***立 (mesa)之製程； E. 於該氮化錄發光一極體上，製作透光導電層以及電 極； F. 在基板底面與數該蝕刻孔洞内壁鍍上一層反射金 屬層薄膜。 其中’於步驟F後可新增一步驟G，該G步驟為電鏟銅 於數該蝕刻孔洞内，以填滿該蝕刻孔洞。 其中’該步驟F所述之反射金屬層薄膜可為 Ti/Al/Ti/Au金屬薄膜。 以下係提供一較佳實施例的製造方法： 〔實施例〕 1 ·試片之研磨與清洗 請參閱第七圖，本發明使用的磊晶片是成長於藍寶石 (sapphire)基板（2〇)的氮化鎵發光二極體（GaN LED)(21)， 在元件開始製作之前必須先將磊晶片使用研磨的方式將藍 寶石基板（20)磨薄至i50um，經過清洗，使用丙酮去除油 201145594 脂’倒入燒杯中後將磊晶片放入，並將整個燒杯放入超音 波震洗機震洗’接著再使用異丙醇以相同的方法放入超音 波震洗機5分鐘，為了去除殘餘的丙酮，最後再使用D. j water震洗，震洗完後用氮氣吹乾即可完成初步清洗。 2.底部藍寶石（sapphire)基板（20)蝕刻 請參閱第七圖，先使用電漿輔助化學氣相沉積法 (plasma enhanced chemical vapor deposition, PECVD) 成長二氧化矽（Si〇2)薄膜（22)，接著再翻到背面成長相同 的二氧化矽薄膜（22)，兩面都有二氧化矽薄膜（22)的原因 是因為在濕钱刻時，二氧化♦能夠保護正面蟲晶層不受敍 刻的傷害。 接著再使用曝光微影技術於藍寶石（sapphire)基板 (⑻面製作出钮刻孔洞之圖形⑵)，並在…晶層使用 光阻完全包覆，即可使用氧化物蝕刻液（buffer 〇χ — 濕#刻出預備飯刻孔洞之圖形 ⑵)，形成钱刻孔洞(24)’最後將試片置於丙酮中震洗以 去除光阻’再以I water清洗。 將晶片放入裝有硫酸和磷酸溶液的結晶皿中，把結晶 皿放上h〇tplate’並用培養皿當蓋+，將結晶皿蓋上，可 使加熱時的蒸氣不會四處飄散’且可讓溫度上升較快速， 並維持溫度穩定；而我們所使用的培養皿上方經過加工， 在上面開有一個直徑“⑽的小洞’可讓溫度計插在培養 201145594 皿的洞裡，以持續觀察在製程中結晶皿内溫度的變化。本 實施例濕式姓刻使用設備所使用的h〇t pUte為德國製 SCHOTT A牌加熱器，表面為精密陶瓷玻璃可耐高溫達 550°C’及具抗強酸腐蝕的能力，且有紅外線加熱的功能； 本實驗所使用的溫度計可量測範圍為-50。〇1 300。(：，加上石 英包覆的細速型熱電偶（ther_uple)，使量測溫度達 500°C，並且有抗強酸的能力。當溫度計顯示的溫度穩定時 ，即可把晶片放入蝕刻液中，並控制蝕刻時間待完成後 馬上把晶片夾起放入D」water中，並用超音波震洗器震 洗，最後再用氮氣吹乾。 3. 平台（mesa)蝕刻 由於先剛已於正面磊晶層成長二氧化矽，所以我們再 次以曝光微影技術定義出平台之圖案，並且以氧化物蝕刻 液蝕刻出平台圖形，再利用感應式耦合電漿蝕刻機 (inductivity coupied Plasma，ICP)蝕刻氮化鎵磊晶結構 層姓刻至露出n型氮化鎵表面為止，最後再使用氧化物 钮刻液將二氧化矽移除，即完成平台蝕刻。 4. 透光導電層以及電極製作 平台蝕刻完之後，接下來便是用電子束蒸鍍機在3χ1〇-6 Torr真空度下，蒸鍍銦錫氧化物（indium tin oxide，IT0) ，並使用熱退火爐管退火之後再使用曝光微影技術定義出 所需要的透明電極，並且以IT0蝕刻液蝕刻掉不需要的透 10 201145594 ”· 3月電極，再以去離子水清洗試片後再吹乾。纟p.n電極的 製程上使用曝光微影技術先定義出電極區域，再以電子束 蒸鍍機蒸鍍Cr/Au電極，接著再把試片放入丙嗣中浸泡， 並以lift-off方式留下電極區域之金屬，最後再使用熱退 火爐管退火，即可完成電極製作。 5.底部藍寶石（sapphire)基板（2〇)電鍍銅填孔 以電子束蒸鑛機3x1 (Γ6 T〇rr真空度下，在藍寳石 (sapphire)面鍍上Ti/A1/Ti/Au薄膜，再使用曝光微影技 術將蝕刻孔之間的間隔以光阻包覆，以避免鋼鍍上孔洞以 外的地方，並將電極面以光阻包覆並硬烤，如此可保護電 極面不受電鍍銅影響，再將欲電鍍之試片置於電鍍槽之陰 極，銅塊（source)置於電鍍槽之陽極，並在硫酸銅溶液中 進行金屬基板之成長。電鍍完成後由電鍍液取出，隨即置 入D. I water中震洗，即完成電鍍銅填孔。 〔本發明量測結果〕 1.發光二極體之背金屬反射之特性 在LED背面的藍寶石（sapphire：^L板上測，我們使用 電子束蒸鍍機來蒸鍍Ti/A1/Ti/Au的背面反射金屬；請參 閱第八圖，由反射率量測的結果，可知在波長46〇nm反射 率可以達到93%左右，而銀膠（Agglue)在全波段的反射率 只有約13%。 請參閱第九及第十圖，在元件的應用上，濕蝕刻過後 11 201145594 具有特殊形狀的藍寶石（sapphire)基板（1〇)與沒有經過濕 蝕刻定義特別形狀相比較，預期可得到更高的光反射再利 用率，由圖中可見，大部分射向底部藍寶石（sapphire)基 板（ίο)的光會更容易被底部的反射金屬層（102)反射出來 ，以增加元件的光取出效率。在反射金屬層（丨〇2)中最外層 使用金（Au)來當作與空氣的阻隔層，可防止銘（A〗）容易氧 化的情形發生；而使用鈦（Ti)是為了當做附著層，並且為 了減少附著層對反射率造成太大影響，所以第一層的鈦 (Ti)只使用較薄厚度，而第三層的鈦（Ti)不僅能夠當做附 著層’也可當做銘（A1)和金（Au)之間防止互相擴散的阻擋 層。 2.電流與光輸出特性 請參閱第十一及第十二圖，在元件電流與光輸出特性 中’我們將實驗（A)、（B)、（C)、（D)四種構造的發光二極 體與一般結構（第十五圖所示之結構）的發光二極體互相作 為比較’由第十二圖中可知在20mA與100mA的操作電流下 ’實驗（A)、（B)、（C)、（D)四種構造與一般結構發光二極 體光輸出倍率分別為表一所示： 表一、發光二極體光輸出倍率光輸出倍率比較 操作 電流 一般 A B C D 20mA 100% 137.47% 262.18% 278.30% 326.95% 100mA 100% 131.66% 245.90% 262.36% 312.12% 12 201145594 結構（A)可看出藍寶石（sapphire)基板（ι〇 )背面鍍上 反射金屬確實得到了 30%〜40%的亮度提昇，而結構（β)、結 構（C)在經過濕姓刻成特殊形狀後，亮度更提昇約丨7左右 :結構（D)除了有反射金屬與特殊結構的幫助，並且在藍寶 石（sapphi re)基板（1 〇 )面的孔洞處填滿了銅，如此可降 低元件的熱效應，並且電鍍銅能夠使整片被磨薄並且蝕刻 過的试片結構更穩定，不容易受到熱效應力的影響而破裂 或是產生其他不良之變異。 清參閱第十三圖，當量測電流增加至丨〇〇mA以上時， 可以看出一般結構的LEI)與背後鍍上反射金屬的LED光輸 出的最同點約在28OmA左右；而結構（]))將銅填入孔洞中， 不但利用高導熱係數取代了空氣，並且使整體試片的結構 更加不易被破壞，能夠確實的將電流提昇至3〇〇mA以上， 才達到光輪出的最高點。 3.電鍍銅影響光之波長偏移研究 請參閱第十一圖與第十四圖’在結構（D)，我們使用電 鑛銅的方式來對濕触刻出的孔洞填銅，目的是為了藉由銅 的间導熱係數來降低熱效應對元件所帶來的影響，而我們 使用電抓對波長偏移的量測來為各種不同實驗試片做比較 由里測結果’我們可以看出所有的試片在1 GOmA下都有 波長藍#的效果，是因為在注入電流時，產生能帶填滿 效應(band fllling⑴如)所致，當施以更高的電流時， 13 201145594 月b帶會爻到熱效應影響而變窄，波長便會產生紅位移的效 果，由第十五圖我們可以看出，在有電鍍填銅的結構（D)， 波長紅位移的值小於其他的實驗試片，由此可見用電鍍鋼 的方式在蝕刻出的孔洞令填孔，確實對元件有較低的熱效 應影響。 透過本發明，藍寶石基板底部經過磨薄與拋光之後， 鍍上反射金屬I，亮度有效提升；而在藍寶石基板底部經 過濕蝕刻後形成不同形狀之基板，在鍍上反射金屬後，由 於其特殊之反射形狀，亮度有更大之提升，並可同時達成 免雷射切割之晶粒切割製程；此外’將銅填進藍寶石基板 的孔/同中’在高電流下可以對減少熱效應、提昇發光效率 加強貫驗試片結構都有顯著的效果。 則文係針對本發明之較佳實施例為本發明之技術特徵 '于’、體之說明’惟’熟悉此項技術之人士當可在不脫離 本發明之精神與原則下對本發明進行變更與修改，而該等 變更與修改，皆應涵蓋於如下申請專利範圍所界定之範疇 中。 ％ 【圖式簡單說明】 第—圓：本發明第一實施例之結構圖。 第二圖：本發明第一實施例之切割位置示意圖。 第~圖·本發明第二實施例之結構圖。 第四圖.本發明第二實施例之切割位置示意圖。 14 201145594 第五圖：本發明第一實施例電鍍填銅於孔洞之結構圖。 第六圖：本發明之製造方法流程圖。 第七圖：本發明其一製造方法實施例之基板底部蝕 J于匕 >同 流程圖。 第八圖：本發明之反射金屬層與其他反射金屬之反射率量 測比較圖。 第九圖：本發明第一實施例之光執跡示意圖。 第十圖：本發明第二實施例之光軌跡示意圖。 第十一圖：電流與光輸出特性所測試的、（⑺、（⑴ 四種構造結構圖。 第十二圖：各種結構的電流與光輸出特性測試比較圖。 第十二圖：各種結構的電流與光輸出特性測試飽和點曲線 圖。 第十四圖·各種結構的電流對波長位移比較圖。 第十五圖：習知之氮化鎵發光二極體結構圖。 【主要元件符號說明】 •習用部分： (30)(32) 藍寶石基板 (3 1 )無摻雜氮化鎵系 層 η型摻雜氮化鎵系層（3 3 )發光層 (3 5 )透明導電層 (3 7) η型金屬電極 4 J Ρ型摻雜氮化鎵系層 (36)ρ型金屬電極 .本創作邹分： 15 201145594 (1 0 )藍寶石基板 （1 0 1 )孔洞 (102)反射金屬層 （103)銅塊 (1 1 )無摻雜氮化鎵系層 （1 2 ) η型掺雜氮化鎵系層 (1 3 )發光層 （1 4 ) ρ型摻雜氮化鎵系層 (15)透光導電層 （16)ρ型金屬電極 (17)η型金屬電極 （20)藍寶石基板 (2 1 )氮化鎵發光二極體（2 2 )二氧化矽薄膜 (2 3 )蝕刻孔洞之圖形 （2 4 )蝕刻孔洞 16201145594 VI. Description of the Invention: [Technical Field] The present invention provides a gallium nitride light-emitting diode and a method for fabricating the same, and particularly provides a method for etching a hole and vapor-depositing a metal layer by a bottom of a substrate. And a GaN light-emitting diode which is further improved in brightness by the copper filling of the electric key, and a manufacturing method thereof. [Prior Art] The general gallium nitride light-emitting diode manufacturing method is divided into the following steps: Step 1: Grinding and cleaning of the test piece: A GaN LED test piece grown on a sapphire substrate, first using a grinding method to sapphire ( Sapphire) The substrate is thinned to 150μηη, after cleaning, remove the grease with acetone, pour into the beaker, place the epitaxial wafer, and put the whole beaker into the ultrasonic washing machine for shock washing, then use isopropanol to the same The method is placed in ultrasonic washing, in order to remove residual acetone, and finally D·丨 shock washing is used. After the shaking, the preliminary cleaning is completed by blowing with nitrogen; Step 2: Mesa etching: frontal epitaxy Layer growth of cerium oxide (Si〇2), the pattern of the platform is defined by exposure lithography, and the platform is engraved with an oxide etched button. Figure %, and then inductivity (4) engraving (inductivity coupied Piasma, icp) etching the gallium nitride epitaxial layer 'etched to the (iv) n-type gallium nitride surface, and finally removing the germanium dioxide using an oxide etchant to complete the platform etching; step three Conductive layer and electrode fabrication: After the platform is etched 3 201145594, the next step is to evaporate indium tin oxide (ΙΤ0) under vacuum in an electron beam evaporation machine and anneal using a thermal annealing furnace tube. Then, using the exposure lithography technique to define the desired transparent electrode, and etching the unnecessary transparent electrode with ΙΤ0 etching solution, and then washing the test piece with deionized water and then drying it. The electrode area is defined by the exposure lithography technique on the process of the ρ and η electrodes, and then the ruthenium electrode is evaporated by an electron beam evaporation machine, and then the test piece is immersed in acetone, and f is removed. The method of leaving the metal in the electrode area is finally finished using a thermal annealing furnace tube to complete the electrode fabrication. The gallium nitride light-emitting diode manufactured by the above manufacturing method has a structure as shown in FIG. 15 'mainly including a sapphire substrate (30) and an undoped gallium nitride layer from bottom to top ( 31) an n-type doped gallium nitride layer (32), a light emitting layer (MQW) (33), a p-type doped gallium nitride layer (34); and a transparent conductive layer (35) Above the p-type doped gallium nitride layer (34), and a p-type metal electrode (36) on the transparent conductive layer (35); and removing part of the p-type doped nitrogen by etching After the gallium layer (34) and the partial light emitting layer (33) are formed, an n-type metal electrode (37) can be formed on the exposed n-type doped gallium nitride layer (32). However, in the above conventional gallium nitride light-emitting diode, light is emitted from the light-emitting layer (33) in all directions when light is emitted, and part of the light is emitted toward the sapphire substrate (30), and is directly emitted from the bottom of the sapphire substrate (30). Can not be fully utilized. 201145594 Therefore, in view of the problems existing in the above-mentioned structure hall, how to develop a kind of innovative society with more ideal and practicality, the consumers are eagerly awaiting, and the relevant industry must work hard to develop the target. . In view of the fact that the inventor has been engaged in the manufacturing development and design experience of related products in the following years, the invention has been put into practical use for the above-mentioned objectives > SUMMARY OF THE INVENTION The gallium nitride light-emitting diode is partially emitted toward the sapphire substrate and cannot be fully utilized. The technical problem to be solved: the light emitted from all directions of the light-emitting layer in the light of the light is solved by the bottom of the sapphire substrate. In order to improve the above problems, the present invention provides a nitrogen with a back mirror and a heat dissipation layer. a gallium-emitting diode, which includes a sapphire substrate, an undoped gallium layer, an n-type doped gallium nitride layer, a zigzag-doped layer, An illuminating layer is characterized in that: a bottom concave hole is formed in the bottom of the sapphire substrate and vapor-deposited to form a reflective metal layer on the bottom of the sapphire substrate and a plurality of inner walls of the hole, whereby the light emitted from the luminescent layer is transparent The reflective metal layer reflects upwards to greatly increase the luminance of the gallium nitride light-emitting diode. The present invention further provides a method for fabricating a gallium nitride light-emitting diode having a back surface mirror and a heat dissipation layer as described above. The bottom of the sapphire substrate of the test piece is silver-cut to form a plurality of concave holes, and is vapor-deposited to form a reflective metal. Layered on the bottom of the blue 201145594 gem substrate and the inner wall of the hole, whereby the light emitted downward from the light-emitting layer can be reflected upward through the reflective metal layer, thereby greatly increasing the brightness of the gallium nitride light-emitting diode. Wherein, a copper block can be electroplated to fill the etching hole, thereby reducing thermal effect generation and further improving luminous efficiency. 0 Compared with the prior art, the present invention forms a plurality of concave holes and vapor deposition reflection by etching the bottom of the substrate. The metal layer can reflect the light emitted toward the bottom to achieve the improvement of the brightness of the light, and fill the hole by electroplating copper, thereby reducing the heat effect and further improving the luminous efficiency. With regard to the technology, the means and the functions of the present invention, it is to be understood that the above-mentioned objects, structures and features of the present invention will be described in detail with reference to the drawings. . [Embodiment] Referring to the first to fifth figures, the present invention provides a gallium nitride light-emitting diode having a back mirror and a heat dissipation layer, which sequentially includes a sapphire substrate (10) from bottom to top, An undoped gallium nitride layer (丨丨), an n-type inductive gallium nitride layer (12), a light emitting layer (MQW) (13), and a p-type alternating gallium nitride layer (14) ), characterized in that: the bottom of the sapphire substrate (10) is formed with a number of concave holes (1 〇 1 ) and vapor deposited to form a reflective metal layer (102) at the bottom of the sapphire substrate (1 与) The inner wall of the hole (101), whereby the light emitted downward from the light-emitting layer (13) can be reflected upward through the reflective metal layer (102), thereby greatly increasing the light emission of the nitrogen 201145594 gallium-emitting diode brightness. Wherein, in the hole (101) after vapor deposition to form a reflective metal layer (1 〇 2 ), a copper block (103) may be electroplated to fill the hole (1〇1), thereby reducing the thermal effect. The light-transmissive conductive layer (15) can be stacked on the P-type doped gallium nitride layer (14). The light-transmissive conductive layer (15) is an indium tin oxide (ITO). Wherein, the p-type metal electrode (16) can be formed on the light-transmissive conductive layer (15). The p-type metal electrode (16) can be a Cr/Au electrode. An n-type metal electrode (17) may be formed on the surface of the n-type doped gallium nitride layer (12), and the n-type metal electrode (17) may be a Cr/Au electrode. Wherein, the holes (1〇1) formed by etching at the bottom of the sapphire substrate (10) are differently spaced, and the shape of the sapphire substrate (10) is also different, and the sapphire substrate (1.) can be formed after being cut. a trapezoidal sapphire substrate ((8) (please refer to the third and fourth figures) or a sapphire (4) with a concave-hole (m) and this embodiment uses the inexacting method to perform the last name of the hole (101), so the hole (ι〇ι) The bottom portion will be planar. Referring to the sixth figure, the manufacturing method of the present invention is sequentially performed as a test piece of a gallium luminescent LED (GaN LED); B. formed on both sides of the test piece. A different _ 喈 - Gonghua 矽 (Si〇2) A. Provide - cleaned test piece, the test substrate grows - nitrogen film 201145594 c. Use exposure lithography technology to create a pattern ' Then use the oxide I insect engraving (buffer 〇xide etching, ΒΟΕ, ΗΡ. Η 2〇-1.6) Ί insect engraving, and form a number of concave contact holes; D. s sth. Physically performing a platform independent (mesa) process on the test piece; E. on the nitrided light emitting body Making a light-transmissive conductive layer and an electrode; F. depositing a reflective metal film on the bottom surface of the substrate and the inner wall of the etching hole. Wherein, a step G may be added after the step F, and the G step is the number of the electric shovel copper. The etching hole is filled in the hole to fill the etching hole. The film of the reflective metal layer described in the step F may be a Ti/Al/Ti/Au metal film. The following is a manufacturing method of a preferred embodiment: 】 1 · Grinding and cleaning of the test piece, please refer to the seventh figure. The epitaxial wafer used in the present invention is a gallium nitride light-emitting diode (GaN) (21) grown on a sapphire substrate (2). Before the component is started, the sapphire substrate (20) must be ground to i50um by grinding. After cleaning, use acetone to remove oil 201145594. After pouring into the beaker, put the wafer into the beaker and place the whole beaker. Into the ultrasonic washing machine shock washing 'and then use isopropyl alcohol in the same way into the ultrasonic shock washing machine for 5 minutes, in order to remove residual acetone, and finally use D. j water shock wash, after the shock wash Dry with nitrogen Step cleaning 2. Bottom sapphire substrate (20) etching Please refer to the seventh figure, first using plasma enhanced chemical vapor deposition (PECVD) to grow cerium oxide (Si〇2) film (22), and then turn to the back to grow the same cerium oxide film (22), both sides have ruthenium dioxide film (22) because the oxidized ♦ can protect the front worm layer during wet etching Subject to the damage of the legend. Then use the exposure lithography technique on the sapphire substrate (the pattern of the button hole (2) is formed on the (8) surface), and the photoresist layer is completely coated with the photoresist layer, and the oxide etchant (buffer 〇χ can be used). Wet# engrave the pattern of the hole in the prepared meal (2)), form the hole in the hole (24)' Finally, the test piece is placed in acetone to be shaken to remove the photoresist' and then washed with I water. Place the wafer in a crystallizing dish containing sulfuric acid and phosphoric acid solution, place the crystallizing dish on h〇tplate' and cover it with a petri dish, and cover the crystallizing dish so that the vapor during heating will not drift around. Let the temperature rise faster and maintain the temperature stability; and the culture dish we used above is processed, and a diameter "(10) hole" is placed on it to allow the thermometer to be inserted into the hole of the 201145594 dish for continuous observation. The change of the temperature in the crystallizing dish in the process. In this example, the h〇t pUte used in the wet type engraving equipment is a SCHOTT A brand heater made in Germany, and the surface is made of precision ceramic glass, which can withstand high temperature up to 550 °C' and has resistance. Strong acid corrosion resistance and infrared heating function; The thermometer used in this experiment can measure from -50 to 3001 300. (:, plus quartz-coated fine-speed thermocouple (ther_uple), The temperature is up to 500 ° C, and has the ability to resist strong acid. When the temperature indicated by the thermometer is stable, the wafer can be placed in the etching solution, and the etching time is controlled to be put into the D"water immediately after the completion of the etching. It is shaken with an ultrasonic scrubber and finally blown dry with nitrogen. 3. Mesa etching Since the cerium oxide has just grown in the front epitaxial layer, we have again defined the pattern of the platform by exposure lithography. And etching the platform pattern with an oxide etching solution, and then etching the gallium nitride epitaxial layer by using an inductivity coupled plasma (ICP) to expose the n-type gallium nitride surface, and finally The cerium oxide is removed by using an oxide button engraving, that is, the etching of the platform is completed. 4. After the transparent conductive layer and the electrode fabrication platform are etched, the next step is to use an electron beam evaporation machine at a vacuum of 3χ1〇-6 Torr. Under the indium tin oxide (IT0), and after annealing using a thermal annealing furnace tube, use the exposure lithography technology to define the required transparent electrode, and etch away the unwanted penetration with the IT0 etching solution. ”· March electrode, then clean the test piece with deionized water and then dry it. The process of 纟pn electrode uses the exposure lithography technology to define the electrode area first, then evaporate with electron beam evaporation machine. The Cr/Au electrode is then immersed in a propane, and the metal in the electrode area is left in a lift-off manner, and finally the electrode is fabricated by annealing with a thermal annealing tube. 5. Bottom sapphire ( Sapphire) substrate (2〇) electroplated copper fill hole with electron beam steamer 3x1 (Γ6 T〇rr vacuum, sapphire surface is coated with Ti/A1/Ti/Au film, then use exposure lithography The technique coats the gap between the etched holes with a photoresist to prevent the steel from being plated outside the hole, and coats the electrode surface with a photoresist and hard-baked, thus protecting the electrode surface from the influence of electroplating copper, and then The test piece to be electroplated is placed at the cathode of the plating bath, the source of the copper is placed at the anode of the plating bath, and the growth of the metal substrate is carried out in a copper sulfate solution. After the electroplating is completed, it is taken out by the plating solution, and then the D. I water is shaken in, and the electroplated copper is filled. [Measurement Results of the Invention] 1. The characteristics of the back metal reflection of the light-emitting diode are measured on the sapphire of the LED (sapphire: ^L plate, we use an electron beam evaporation machine to vaporize Ti/A1/Ti/Au Reflected metal on the back side; please refer to the eighth figure. From the results of reflectance measurement, it can be seen that the reflectivity at the wavelength of 46 〇nm can reach about 93%, while the reflectivity of Agglue in the whole band is only about 13%. Please refer to the ninth and tenth figures. In the application of the component, the wet-etched 11 201145594 sapphire substrate (1〇) with a special shape is expected to be higher than the special shape without wet etching. Light reflection re-utilization, as can be seen from the figure, most of the light that is directed toward the bottom sapphire substrate ( ίο) will be more easily reflected by the bottom reflective metal layer (102) to increase the light extraction efficiency of the component. The outermost layer of the reflective metal layer (丨〇2) uses gold (Au) as a barrier layer with air to prevent the occurrence of easy oxidation (M), while titanium (Ti) is used as an adhesion layer. And in order to reduce the attachment The layer has too much influence on the reflectivity, so the first layer of titanium (Ti) uses only a thinner thickness, while the third layer of titanium (Ti) can be used not only as an adhesion layer but also as an imprint (A1) and gold (Ti). Au) A barrier layer that prevents interdiffusion. 2. For current and light output characteristics, see Figures 11 and 12. In the component current and light output characteristics, we will experiment (A), (B), ( C), (D) The light-emitting diodes of the four structures and the light-emitting diodes of the general structure (the structure shown in Fig. 15) are compared with each other. 'The operating current at 20 mA and 100 mA is known from the twelfth figure. The light output magnifications of the following four experiments (A), (B), (C), and (D) and the general structure of the light-emitting diode are shown in Table 1: Table 1. Light output of the light-emitting diode Magnification comparison operation current general ABCD 20mA 100% 137.47% 262.18% 278.30% 326.95% 100mA 100% 131.66% 245.90% 262.36% 312.12% 12 201145594 Structure (A) can be seen on the back of sapphire (sapphire) substrate (ι〇) plated with reflection The metal does get a brightness increase of 30% to 40%, while the structure (β), knot After the structure (C) is carved into a special shape by wetness, the brightness is increased by about 丨7: the structure (D) is in addition to the help of reflective metal and special structure, and is on the surface of the sapphire substrate (1 〇). The hole is filled with copper, which reduces the thermal effect of the component, and the copper plating can make the entire piece of the thinned and etched test piece structure more stable, not susceptible to thermal effect forces, or other undesirable variations. . Referring to the thirteenth figure, when the equivalent current is increased above 丨〇〇mA, it can be seen that the LEI of the general structure is about 28OmA with the LED light output of the reflective metal behind it; ])) Filling the holes into the holes not only replaces the air with high thermal conductivity, but also makes the structure of the whole test piece less susceptible to damage. It can surely raise the current to more than 3 mA to reach the highest light output. point. 3. Electroplating copper affects the wavelength shift of light. Please refer to Figure 11 and Figure 14. In Structure (D), we use copper ore to fill the holes in the wet contact. The purpose is to By using the thermal conductivity between copper to reduce the effect of thermal effects on the components, we use the electric offset to measure the wavelength shift to compare various experimental test pieces. The results of the test are 'we can see all the The test piece has the effect of wavelength blue # at 1 GOmA because the band filling effect (band fllling (1), for example) occurs when the current is injected. When a higher current is applied, 13 201145594 b When the effect of the thermal effect is narrowed, the wavelength will produce a red displacement effect. From the fifteenth figure, we can see that in the structure with electroplated copper (D), the value of the wavelength red shift is smaller than other experimental test pieces. It can be seen that the etched holes in the way of galvanizing steel make the holes fill, which has a low thermal effect on the components. Through the invention, after the bottom of the sapphire substrate is thinned and polished, the reflective metal I is plated, and the brightness is effectively improved; and after the wet etching on the bottom of the sapphire substrate, different shapes of the substrate are formed, and after the reflective metal is plated, due to its special Reflective shape, brightness is improved, and the laser cutting process can be achieved at the same time. In addition, 'filling copper into the hole/same of the sapphire substrate' can reduce the thermal effect and improve the luminous efficiency at high current. Strengthening the structure of the test piece has a significant effect. The present invention is directed to the preferred embodiment of the present invention, which is a technical feature of the present invention, and the subject matter of the present invention can be changed and modified without departing from the spirit and scope of the invention. And such changes and modifications shall be covered by the scope of the following patent application. % [Simplified description of the drawings] - Circle: A structural diagram of the first embodiment of the present invention. Second drawing: Schematic diagram of the cutting position of the first embodiment of the present invention. Fig. 1 is a structural view showing a second embodiment of the present invention. Figure 4 is a schematic view showing the cutting position of the second embodiment of the present invention. 14 201145594 Fig. 5 is a structural view showing the electroplating of copper in the hole in the first embodiment of the present invention. Figure 6 is a flow chart showing the manufacturing method of the present invention. Figure 7 is a bottom view of a substrate of an embodiment of the manufacturing method of the present invention. Figure 8 is a graph comparing the reflectance of the reflective metal layer of the present invention with other reflective metals. Figure 9 is a schematic view of the light trace of the first embodiment of the present invention. Figure 11 is a schematic view showing the light trajectory of the second embodiment of the present invention. Figure 11: Current and light output characteristics tested ((7), ((1) four structural diagrams. Twelfth: Comparison of current and light output characteristics of various structures. Figure 12: Various structures Current and light output characteristics test saturation point graph. Figure XIV. Comparison of current versus wavelength displacement of various structures. Figure 15: Structure of a conventional gallium nitride light-emitting diode. [Key component symbol description] Conventional part: (30) (32) sapphire substrate (3 1 ) undoped gallium nitride layer n-type doped gallium nitride layer (3 3 ) luminescent layer (3 5 ) transparent conductive layer (3 7) η Metal electrode 4 J Ρ-type doped gallium nitride layer (36) p-type metal electrode. This creation is divided into: 15 201145594 (1 0 ) sapphire substrate (1 0 1) hole (102) reflective metal layer (103) Copper block (1 1 ) undoped gallium nitride layer (1 2 ) n-type doped gallium nitride layer (1 3 ) light-emitting layer (1 4 ) p-type doped gallium nitride layer (15) Photoconductive layer (16) p-type metal electrode (17) n-type metal electrode (20) sapphire substrate (2 1 ) gallium nitride light-emitting diode (2 2 ) ceria film (2 3 ) etching the hole pattern (2 4) etching the hole 16