201216333 六、發明說明： 【發明所屬之技術領域】 本發明係關於用以在藉由化合物半導體所形成的半導 體發光元件的製造製程中，對形成在基板上的材料層照射 雷射光，藉此將該材料層分解而由該基板剝離（以下稱爲 雷射剝離）的雷射剝離方法及雷射剝離裝置。 尤其，本發明係關於一面時時刻刻改變工件上的雷射 光照射領域，一面使被照射在工件上相鄰接的照射領域的 各雷射光相重疊而照射雷射光，藉此將材料層由基板剝離 的雷射剝離方法及雷射剝離裝置。 術 技 前 先 在藉由GaN (氮化鎵）系化合物半導體所形成的半導 體發光元件的製造製程中，將形成在藍寶石基板之上的 GaN系化合物結晶層，藉由由該藍寶石基板的背面照射雷 射光來進行剝離的雷射剝離的技術已爲人所知。 例如，在專利文獻1中，係關於在藍寶石基板之上形 成GaN層，由該藍寶石基板的背面照射雷射光，藉此使形 成GaN層的GaN分解，而將該GaN層由藍寶石基板剝離的 技術有所記載。 但是，爲了將形成在藍寶石基板之上的GaN系化合物 結晶層，藉由由該藍寶石基板的背面照射雷射光來進行剝 離，照射具有用以將GaN系化合物分解爲Ga與N2所需的分 解臨限値以上的照射能量的雷射光乃極爲重要。 -5- 201216333 在此，在照射雷射光時，由於GaN分解而發生N2氣體 ，因此對該GaN層施加剪切應力，會有在該雷射光的照射 領域的交界部發生裂痕的情形。例如，如第1 〇圖所示，若 雷射光的1發射的照射領域1 1〇爲正方形狀，會有在GaN層 1 1 1的雷射光照射領域的交界1 1 2發生裂痕的問題。 尤其，若使用數μιη以下厚度的GaN系化合物結晶層來 形成元件時，亦會有GaN系化合物結晶層不具有用以承受 因N2氣體發生所造成的剪切應力的充分強度的情形，而容 易發生裂痕。此外，不僅GaN系化合物結晶層，裂痕在形 成於其上的結晶層傳播，亦會有元件本身受到破壞的情形 ，造成形成微小尺寸元件時的問題。 針對該問題，在專利文獻2係揭示一種技術，其形成 用以將形成在藍寶石基板上的GaN層以與半導體發光元件 的晶片相對應的方式進行分離的界道（street )，在執行 雷射剝離工程中，藉由該界道來緩和在藍寶石基板與GaN 層的界面所發生的殘留應力。 根據該文獻，將GaN層分割爲小領域，使得因來自周 圍的殘留應力所造成的影響爲最小，此外，小領域本身係 僅有最小的殘留應力，藉此可減低雷射剝離當中的GaN層 的破損。 如上所示，在GaN層形成界道（晶片分離用交界線： 切割線）而執行雷射剝離工程時，較佳爲如專利文獻2的 Fig. 1 3所示，以雷射光的照射領域的邊緣部與該界道相一 致的方式照射雷射光。此係基於雖然各雷射光的照射領域 ⑧ -6 - 201216333 必然地使各自的端部彼此相重疊，但是若各雷射光的照射 領域在GaN層的表面（亦即界道以外的部分）中相重疊時 ，被照射在該重疊領域的雷射光的能量會變得過大，因此 會有在GaN層發生不良影響之虞之故。 但是，若在GaN層形成界道，爲了緩和前述殘留應力 ，必須將界道的寬幅加大一定程度，但是由於如此，會有 由1枚藍寶石基板所採取的半導體發光元件的晶片個數會 減少的問題。 然後，在GaN層形成界道時，必須以雷射光的照射領 域的邊緣部與界道相一致的方式，將雷射光的照射領域與 形成在藍寶石基板上的GaN層精度佳地進行對準。因此， 減小界道的寬幅時，不易將雷射光的照射領域的邊緣部精 度佳地對準在形成於GaN層的界道上，不僅供對準之用的 裝置構成變得較爲複雜，亦變得較難進行其操作/管理》 此外，在每次半導體發光元件的晶片尺寸不同時，即 必須進行上述對準，因此會產生雷射剝離工程極爲複雜化 的問題。 另一方面，在專利文獻3中揭示一種技術，其並非如 上所述在GaN層形成界道，而是以減低GaN層的破損爲目 的，如第1 1圖所示，以對於藍寶石基板121與GaN系化合物 的結晶層122的界面的照射領域123成爲線狀的方式成形雷 射光124，一面使藍寶石基板121朝向與雷射光124的長邊 方向呈垂直方向移動，一面由藍寶石基板121的背面照射 該雷射光124。在該文獻中記載雷射光124以成爲光學系統 201216333 之解析度以下的線幅的方式進行成形，藉此如第12圖所示 ，雷射光124的線幅方向的光強度分布在大致中央具有峰 値而由該峰値朝向邊緣部平緩地形成。 根據該文獻，將雷射光1 24如上所述進行成形，藉此 不會在照射於將雷射光1 24照射在結晶層1 22時的雷射光 1 24的線幅方向的邊緣部的照射領域進行急劇的雷射剝蝕 。因此，在屬於GaN層的結晶層122分解時不會有急劇發生 N2的情形，因此不會對結晶層122施加過量的應力，可減 低對結晶層1 2 2及形成在其上的元件發生裂痕。 但是，本發明人等査證上述專利文獻3所揭示的雷射 剝離工程，結果確認出減低在屬於GaN層的結晶層所發生 的破損的效果並不充分。 〔先前技術文獻〕 〔專利文獻〕 [專利文獻1]日本特表2001-501778號公報 [專利文獻2]日本特表2007-534164號公報 [專利文獻3]日本特開2003-168820號公報 【發明內容】 (發明所欲解決之課題） 具體而言’本發明人等係按照專利文獻3，確認出使 形成在藍寶石基板上的結晶層朝向與以線狀成形的雷射光 的長邊方向呈垂直的方向移動，適當變更藍寶石基板的移 動速度及間歇性照射的脈衝雷射光的照射間隔，將以線狀 ⑧ -8 - 201216333 成形的雷射光照射在結晶層，結果會在屬於結晶層的GaN 層發生裂痕。 本發明係爲解決上述問題點而硏創者，本發明之第i 目的在提供不會在形成於基板上的結晶層（以下稱爲材料 層）發生破損’可將該材料層由該基板剝離的雷射剝離方 法及雷射剝離裝置。 此外’本發明之第2目的在提供不會藉由供予用以使 材料層由基板剝離所需之充分的雷射能量而在形成於基板 上的材料層發生破損’而且不會發生材料層再接著在基板 等不良情形’可將該材料層由該基板剝離的雷射剝離方法 及雷射剝離裝置。 (解決課題之手段） 在雷射剝離中，一般進行使形成有材料層的藍寶石基 板（以下稱爲工件）或雷射源掃描，一面時時刻刻改變對 工件的雷射光的照射領域，一面對材料層照射雷射光。此 係基於不易使由雷射源出射的雷射光的照射領域形成爲與 工件爲同等大小之故。因此，工件上相鄰接的各雷射光的 照射領域的邊緣部係必然相重疊，但是在雷射剝離工程中 ’要如何使各雷射光相重疊乃極爲重要。關於此，使用第 2圖加以說明。 在雷射剝離工程中，係使用出射脈衝雷射光的雷射源 ’以雷射光的照射領域時時刻刻改變的方式來照射雷射光 。亦即，若使用後述的第2圖加以說明，在對脈衝雷射光 -9 - 201216333 的照射領域s 1照射雷射光後’搬送工件或雷射源而對接下 來的領域S 2照射雷射光。此時，脈衝雷射光的照射領域S 1 與S2的各自的邊緣部會相重疊。 在此，在照射領域S1與S2的各自的邊緣部相重疊的領 域ST中，基於以下理由，被照射在照射領域S1及S2的各個 領域的脈衝雷射光的照射量未被積算。此係基於在對照射 領域S 1照射雷射光後使照射領域由S 1移至S2時，照射領域 S1的GaN的溫度降至至室溫水準爲止所需時間會遠短於使 照射領域由S1移至S2爲止的時間，因此領域S1的溫度係成 爲已降低至室溫水準的狀態之故。 本發明人等藉由模擬進行檢討後的結果，照射領域S 1 的GaN的溫度降低至室溫水準爲止所需時間係被推定爲100 微秒以內。假設在照射領域S 1的溫度已降低至室溫水準的 狀態下對照射領域S2照射雷射光，照射領域S 1與S2相重疊 的領域ST亦僅藉由被照射在照射領域S2的雷射光而予以加 熱。 如上所示，在照射領域SI、S2相重疊的領域ST中，被 照射在各自的照射領域S 1、S2的脈衝雷射光的照射量未被 積算，因此必須使被照射在領域S 1、S2的各個領域的脈衝 雷射光在超過材料層之分解臨限値的能量領域中相重疊。 另一方面，確認出若上述照射領域S1與S2的各自的邊 緣部相重疊的領域ST中各自的脈衝雷射光的強度，相對使 前述材料層由前述基板剝離所需的分解臨限値爲過大時， 會在基板發生材料層再接著等不良情形。 ⑧ -10- 201216333 此被§忍爲係在相同領域，因強度較大的脈衝雷射光被 照射2次’而使一次由基板剝離的材料層因被照射第2次的 脈衝雷射光而再接著。 藉由實驗等可知，各雷射光相重疊的領域中的雷射光 的強度’相對使前述材料層由前述基板剝離所需之分解臨 限値VE’以形成爲VExl.15以下爲宜。因此，爲了避免如 上所述之基板與材料層再接著的不良情形，最好使各雷射 光相重疊的領域中的雷射光的強度不會過大。 在此’若將[雷射光相重疊的領域中的雷射光的強度（ 最大値）]/[分解臨限値VE]定義爲重疊度T，爲了不會在形 成於基板上的材料層發生破損，而使材料層由基板確實剝 離’較佳爲將重疊度T形成爲1ST，此外，爲了避免基板 與材料層的再接著，較佳爲形成爲TS1.15。 根據以上，在本發明中，如以下所示來解決前述課題 〇 (1) 一種雷射剝離方法，係通過在基板上形成有材 料層而成的前述基板而照射脈衝雷射光，在前述基板與前 述材料層的界面，將前述材料層由前述基板剝離的雷射剝 離方法，其中，將前述脈衝雷射光一面時時刻刻改變對工 件的照射領域，一面以在前述工件中相鄰接的各照射領域 相重疊的方式進行照射，相重疊的各個的脈衝雷射光的大 小係成爲超過使前述材料層由前述基板剝離所需的分解臨 限値的能量的大小。 (2 )在上述（1 )中，將被照射在前述工件中相鄰接 -11 - 201216333 的各照射領域的各雷射光相重疊的領域中的雷射光的強度 ，相對使前述材料層由前述基板剝離所需的分解臨限値VE ，形成爲VExl.15以下。 (3)在上述（1) (2)中，將前述工件依序執行： 朝第1搬送方向搬送的第1搬送動作；朝向與第1搬送動作 的搬送方向呈正交的方向搬送的第2搬送動作：及朝向與 前述第1搬送動作的搬送方向相差180°的方向搬送的第3 搬送動作，依序對各照射領域照射前述脈衝雷射光。 (4 )在進行上述雷射剝離的雷射剝離裝置中，成形 由雷射源所發出的脈衝雷射光，設置照射在前述工件之具 有投影透鏡的雷射光學系統，前述工件的光入射面以在前 述雷射光的光軸方向中與前述投影透鏡的焦點位置不相一 致的方式作配置。 (發明之效果） 藉由本發明之雷射剝離方法，可期待以下效果。 (1 )由於被照射在工件上相鄰接的照射領域的雷射 光在超過用以將材料層分解所需的分解臨限値的能量領域 中相重疊，因此在各雷射光以相重疊的方式進行照射的領 域中，被供予用以使材料層由基板剝離所需之充分的雷射 能量，因此在形成於基板上的材料層不會發生破損，而可 使材料層由基板確實剝離。 (2 )將被照射在相鄰接的各照射領域的各雷射光相 重疊的領域中的雷射光的強度，相對使前述材料層由前述 ⑧ -12- 201216333 基板剝離所需的分解臨限値V E，形成爲V Ε χ 1 . 1 5以下，藉 此可避免基板與材料層再接著的不良情形。 (3)工件的光入射面以在前述雷射光的光軸方向中 與前述投影透鏡的焦點位置不相一致的方式作配置，藉此 可將被照射在工件的脈衝雷射光的光束輪廓形成爲平緩的 形狀（將所被照射的脈衝雷射光的周緣部的光照度分布形 成爲由峰値部朝向邊緣部平緩地降低的形狀）。藉此，藉 由調整脈衝雷射光的照射間隔（以一定速度搬送工件時） ，或者調整工件的搬送速度（脈衝雷射光的照射間隔爲一 定時），可改變各雷射光相重疊的領域中的各雷射光的強 度。 【實施方式】 第1圖係說明本發明之實施例之雷射剝離處理槪要的 槪念圖。 如該圖所示，在本實施例中，雷射剝離處理係如下進 行。 在透射雷射光的基板1上形成有材料層2的工件3被載 置在工件載台31上。載置工件3的工件載台31係被載置在 如傳送機般的搬送機構32，藉由搬送機構3 2而以預定速度 進行搬送。工件3係一面連同工件載台31 —起朝向圖中的 箭號ABC方向搬送，一面通過基板1而被照射由未圖示的 脈衝雷射源所出射的脈衝雷射光L。 工件3係在由藍寶石所構成的基板1的表面形成GaN ( -13- 201216333 氮化鎵）系化合物的材料層2而成者。基板1若爲可良好形 成GaN系化合物的材料層，而且透射用以將GaN系化合物 材料層分解所需波長的雷射光者即可。在材料層2係使用 GaN系化合物，俾以藉由較低的輸入能量，效率佳地輸出 高輸出的藍色光。 雷射光應與基板1及構成由基板1剝離的材料層的物質 相對應來作適當選擇。將GaN系化合物的材料層2由藍寶石 的基板1剝離時，係可使用例如放射波長248nm的KrF (氟 化氪）準分子雷射。雷射波長248nm的光能量係位於GaN 的能隙（3.4 e V )與藍寶石的能隙（9 · 9 e V )之間。因此， 波長248 nm的雷射光由於將GaN系化合物的材料層由藍寶 石的基板剝離，故較爲理想。 接著，關於本發明之實施例的雷射剝離處理，使用第 1及2圖加以說明。第2圖係顯示雷射光L被照射在工件3的 態樣圖。 第2圖（a )係顯示對工件3的雷射光的照射方法，第2 圖（b)係放大顯示第2圖（a)的X部者，在第2圖（b)中 係顯示工件3之各照射領域所被照射的雷射光的光強度分 布的剖面之一例。其中，第2圖所示工件3上的實線係僅假 想顯示雷射光的照射領域者。 工件3係藉由搬送機構32而朝向第2圖所示之箭號HA 、HB、HC的方向反覆搬送。雷射光L係由藍寶石的基板1 的背面被照射，被照射在基板1與材料層2的界面。雷射光 L的形狀係成形爲大致方形狀。 -14- 201216333 如第1、2圖所示，工件3係與工件本身的尺寸相對應 依序執行：朝向第1圖的箭號A的方向搬送的第1搬送動作 Η A ;以由相當於雷射光之1發射的照射領域S的距離減掉 重疊領域ST後的距離，朝向與第1搬送動作HA的搬送方向 呈正交的方向（第1圖的箭號C的方向）搬送的第2搬送動 作HB;及朝向第1圖的箭號B的方向搬送的第3搬送動作HC 。第1搬送動作HA及第3搬送動作HC的各個的搬送方向係 相差1 80°。 在此，雷射光的光學系統係保持在被固定的情況下， 並未被搬送。亦即，在將雷射光的光學系統固定的狀態下 僅搬送工件3，藉此會使工件3中的雷射光L的照射領域如 第2圖的箭號所示，依S 1至S 1 2的順序相對上時時刻刻在改 變。 接著，針對本發明之實施例的雷射剝離處理，更加具 體說明。在第2圖所示之實施例中，工件3係具有圓形狀輪 廓者，惟針對雷射光的照射領域形成爲大致方形狀，對如 上所示之方形狀照射領域的雷射照射方法加以說明。 如第2圖所示，一面使工件3朝向第2圖的HA方向搬送 ，一面對SI、S2、S3、S4的4個照射領域，分別經過各1次 、合計4次照射雷射光》此爲第1搬送動作。 接著，由於雷射光被照射在工件3之接下來的照射領 域S5，因此將工件3朝向第2圖的HB方向搬送。此爲第2搬 送動作。工件3朝向箭號HB方向搬送的距離係等於由相當 於脈衝雷射光的1發射（1脈衝）份的照射領域的距離減掉 -15- 201216333 重疊領域ST後所得的距離》 接著，一面使工件3朝向第2圖的HC方向搬送，一面對 S5、S6、S7、S8、S9、S10的6個照射領域，分別經過各1 次、合計6次照射雷射光。此爲第3搬送動作。關於工件3 的其他照射領域，亦按照上述一連串順序來搬送工件3， 藉此遍及工件3的全域來照射雷射光。 雷射光的照射領域係如第2圖所示按照SI、S2、S3的 順序相對移動，但是各自的照射領域爲例如0.5mmx〇.5mm ，面積爲0.25mm2。相對於此，工件3的面積爲4560mm2。 亦即，雷射光的照射領域S 1、S2、S3係遠小於工件面積。 在本實施例的雷射剝離處理中，小於工件3的照射領域 的雷射光一面朝向第1圖所示箭號A及B的方向（亦即工件 的左右方向）掃描，一面對工件3進行照射。其中，與本 發明之實施例相反地，亦可保持將工件固定，按照上述搬 送動作HA至HC搬送雷射的光學系統。簡單地說，若以工 件上的雷射光的照射領域隨同時間時時刻刻變化的方式， 對工件照射雷射光即可。 在此，在本發明之雷射剝離處理中，如第2圖（b )所 示’雷射光在工件3彼此相鄰接的照射領域SI、S2、S3中 ，以間歇性照射的各雷射光的寬幅方向的端部彼此相重疊 的方式被照射在工件3。雷射光L係脈衝雷射光，間歇性被 照射在工件3。在工件3的照射領域S 1、S 2、S 3中，雷射光 相重疊的寬幅爲例如0.1 mm。 雷射光的脈衝間隔係考慮到工件3的搬送速度、及被 -16- 201216333 照射在工件3上相鄰接之照射領域S 1、S2、S3、…的雷射 光的重疊領域S T的寬幅來作適當設定。 基本上，以在工件3移動至接下來的照射領域之前不 會有雷射光被照射在工件的情形的方式，來決定雷射光的 脈衝間隔。亦即，雷射光的脈衝間隔係被設定爲比工件3 移動相當於雷射光之1發射份的照射領域的距離所需時間 爲更長。例如，工件3的搬送速度爲100mm/秒，雷射光的 重疊領域ST的寬幅爲0.1mm時，雷射光的脈衝間隔爲0.004 秒（250Hz)。 第3圖係顯示以在第2圖所示之工件3之彼此相鄰接的 領域S 1、S2相重疊的方式照射在工件的雷射光的光強度分 布圖，爲第2圖（b )中的a-a’線剖面圖。 該圖中縱軸係表示被照射在工件之各照射領域的雷射 光的強度（能量値），橫軸係表示工件的搬送方向。此外 ’ L 1、L2係表示分別被照射在工件的照射領域S 1、S 2的雷 射光的輪廓（profile)。其中，雷射光LI、L2並非同時照 射’而是在雷射光L1被照射之後，間隔1脈衝後再照射雷 射光L2。 在該例中，如第3圖所示，雷射光L 1、L2的剖面係 形成爲接續朝圓周方向平緩地擴展的邊緣部LE，在頂點 (峰値能量PE )具有平坦面的大致梯形狀。接著，雷射 光LI、L2係如第3圖中以虛線所示，在超過用以將GaN系 化合物的材料層分解而由藍寶石基板剝離所需的分解臨 限値VE的能量領域中相重疊。 -17- 201216333 亦即，各雷射光的光強度分布中在雷射光L1與L2的交 叉位置C的雷射光的強度（能量値）CE係以成爲超過上述 分解臨限値VE的値的方式進行設定。 此係如前所述，在對第2圖的照射領域S 1照射雷射光 後使照射領域由S 1移至S2時，領域S 1的溫度係成爲已經降 低至室溫水準的狀態，因此假設在照射領域S 1的溫度已降 低至室溫水準的狀態下對照射領域S2照射雷射光，亦使被 照射在各自的照射領域S 1、S2的脈衝雷射光的照射量未被 積算之故。 將在雷射光L1與L2的交叉位置C的雷射光的強度CE， 亦即雷射光相重疊照射的領域中的各自的脈衝雷射光的強 度，以成爲超過上述分解臨限値VE的値的方式進行設定， 藉此可供予用以使材料層由基板剝離所需的充分雷射能量 ，而不會在形成於基板上的材料層發生破損，而可使材料 層由基板確實剝離。亦即，前述段落所定義的重疊度T係 以形成爲1 ST爲宜。 其中，相對於工件3與雷射光的相對移動量，雷射光 的脈衝間隔係以被照射在工件3相鄰接的照射領域的雷射 光如前所述相重疊的方式預先進行調整。在該圖所示之實 施例中，由於材料層爲GaN，因此分解臨限値爲500〜 1 5 00J/cm2。分解臨限値VE係必須按照每個構成材料層的 物質來作設定。 在此，如上所述，可知雷射光L1與L2係在超過分解臨 限値VE的能量領领相重疊，但是如後所述，爲了避免基板 ⑧ -18- 201216333 與材料層再接著的不良情形，必須將相對相重疊的各自雷 射光的分解臨限値VE的大小的比例設定爲適當的値，具體 而言，對上述分解臨限値VE，以成爲VE xl .15以下的方式 作設定爲宜。 在第3圖的實施例中，在各雷射光的光強度分布中在 雷射光L1與L2的交叉位置C的雷射光的強度（能量値）CE 係相對於使前述材料層由前述基板剝離所需之分解臨限値 VE，以成爲VExl.15以下的方式進行設定。 亦即，前述重疊度T係以形成爲TS1.15爲宜。 第4圖係本發明之實施例之雷射剝離裝置的槪念圖。 在該圖中，雷射剝離裝置1 0係具備有：出射前述脈衝雷射 光的雷射源20 ;用以將雷射光成形爲預定形狀的雷射光學 系統40;供載置工件3的工件載台31 ;搬送工件載台31的 搬送機構32 ;及控制在雷射源20所發生的雷射光的照射間 隔及搬送機構32的動作的控制部33 » 光學系統40係具備有：柱狀透鏡41、42 ;朝向工件的 方向反射雷射光的反射鏡43 ;用以將雷射光成形爲預定形 狀的遮罩44;及使通過遮罩44的雷射光L聚光在工件3上的 投影透鏡4 5。 在光學系統40的前方配置有工件3。工件3係被載置於 工件載台31上。工件載台31係被載置於搬送機構32，被搬 送機構32所搬送。藉此’工件3朝向前述第1圖所示的箭號 A、B、C的方向依序搬送，工件3中的雷射光的照射領域 時時刻刻改變。控制部3 3係以被照射在工件3相鄰接的照 -19- 201216333 射領域的各雷射光的重疊度成爲所希望的値的方式，來控 制在雷射源20所發生的脈衝雷射光的脈衝間隔。 由雷射源20所發生的雷射光L係發生波長248nm之紫外 線的例如KrF準分子雷射。以雷射源而言，亦可使用ArF雷 射或Y A G雷射。 在此，工件3的光入射面3A亦可相較於投影透鏡45的 焦點F，在雷射光的光軸方向中配置在較爲遠方側，或者 與其相反地，在雷射光的光軸方向中，將工件3的光入射 面3 A以比投影透鏡45的焦點F更爲接近投影透鏡45的方式 進行配置。如上所示，藉由將工件3的光入射面3 A以與投 影透鏡45的焦點F不相一致的方式作配置，可得如第3圖所 示之具有雷射光LI、L2的光束輪廓的邊緣部LE平緩地降 低且剖面爲梯形狀的光強度分布的雷射光。 在雷射源20所發生的雷射光L係在通過柱狀透鏡41、 42、反射鏡43、遮罩44之後，藉由投影透鏡45被聚光在工 件3上。 藉由投影透鏡45而被入射在工件3的光入射面3A的雷 射光係在第3圖所示剖面中，以具有接續朝圓周方向平緩 地擴展的邊緣部LE而在頂點具有平坦面的大致梯形狀的光 強度分布的方式予以成形。 以與工件相鄰接的照射領域相重疊的方式所照射的各 個雷射光的光強度分布係以如上所述剖面爲大致梯形狀較 爲理想，但是亦可不一定爲梯形狀。 第5圖係顯示被照射在工件的雷射光的光強度分布的 -20- 201216333 其他實施例。 第5圖（a )所示之雷射光的光強度分布係形成爲峰値 位在中央並且具有接續該峰値而平緩地擴展的邊緣部LE的 大致山狀。雷射光的光強度分布係可藉由調整第4圖所示 之投影透鏡45的焦點F與工件3的光入射面3A的距離來作適 當變更。 雷射光的光強度分布係隨著投影透鏡45的焦點F與工 件3的光入射面3A的距離愈接近，愈形成爲清晰的矩形狀 ，隨著投影透鏡45的焦點F與工件3的光入射面3A的距離愈 遠，邊緣愈平緩形成，並且形成爲山狀。 此外，如第5圖（b)所示，亦可將雷射光LI、L2的光 強度分布形成爲矩形狀。此時，若將雷射光L 1、L2相重疊 的領域中的雷射光的強度（在雷射光L1與L2的交叉位置的 雷射光的強度，此時係與雷射光L 1的峰値値相對應）設爲 CE ’前述重疊度T係以T = CE/[分解臨限値VE]進行計算。 在此時亦爲在上述雷射光L1與L2的交叉位置的雷射光 的強度C E係大於使前述材料層由前述基板剝離所需的分解 臨限値VE，而且相對分解臨限値VE，以形成爲VE X 1 · 1 5以 下爲宜。 在此，使用第3圖、第6圖，來說明藉由執行本實施例 之雷射剝離處理所得的效果。 第3圖係顯示本實施例之雷射剝離方法所使用的雷射 光的光強度分布’第6圖係顯示用以與其作比較的雷射光 的光強度分布。第3圖、第6圖的LI、L2係表示被照射在第 -21 - 201216333 2圖所示之SI、S2的照射領域的雷射光。關於被照射在工 件相鄰接的照射領域的雷射光的重疊度對由基板剝離後的 材料層所造成的影響，使用第3、6圖來作比較檢討。 第3圖所示之雷射光LI、L2係具有接續朝圓周方向平 緩地擴展的邊緣部LE而在頂點具有平坦面的大致梯形狀的 光強度分布，而且在超過分解臨限値VE的能量領域中，雷 射光LI、L2係以重疊度T成爲適當的値（1以上、1.15以內 )的方式相重疊。 因此，第3圖的實施例的雷射剝離方法係當雷射光被 照射在與基板1的界面側的材料層2的表面而使構成材料層 2的GaN分解時，不會有急劇發生N2氣體的情形。而且， 第3圖的實施例的雷射剝離方法係由於對第2圖中雷射光L1 與L2相重疊的重疊領域ST所照射的雷射光的能量不會過與 不足而成爲最適能量’因此可避免材料層2與基板1再接著 的不良情形，而可使材料層2由基板1確實剝離。 實際上將如第3圖所示之實施例之雷射光照射在工件 時之剝離後的材料層的表面狀態非常漂亮’並未發現髒污 、損傷等對發光特性造成不良影響者。 相對於此，若將第6圖（a )的比較例所示雷射光照射 在工件時，雷射光L1與L2的各自的光強度分布在低於分解 臨限値V E的能量領域相交叉，因此會有在第2圖所示工件 中，被照射在雷射光L1與L2之重疊領域ST的雷射光能量不 足等不良情形。 實際上若將第6圖（a )所示比較例的雷射光照射在工 -22- 201216333 件時，形成構成材料層的GaN的未分解領域，無法使材料 層由基板充分剝離。GaN的未分解領域係與在工件中雷射 光L1與L2相重疊的重疊領域ST相一致。 另一方面，若將第6圖（b )的比較例所示雷射光照射 在工件時，由於雷射光L1與L2的重疊度T會變得過大，因 此會有在第2圖所示工件中，對雷射光L1與L2的重疊領域 ST照射過剩能量的雷射光的不良情形。 如後述之第7圖（b-4 )所示，將實際上第6圖（b )所 示比較例的雷射光照射在工件時之剝離後的材料層的表面 狀態，係在表面形成多數如黑色污垢般的髒污。 此係被認爲由於能量較大的雷射光照射2次在相同部 位，一次由基板剝離的材料層藉由被照射第2次的雷射光 而再接著，構成基板的藍寶石成分產生附著。如上所示形 成在材料層表面的黑色污垢係對發光特性造成不良影響。 爲確認上述效果，針對雷射光相重疊的照射領域中的 雷射光的重疊度對剝離後的材料層所造成的影響進行實驗 〇 第7圖係顯示其結果的圖。第7圖（a )係顯示實驗所 使用之重疊照射在相鄰接領域的雷射光的光強度分布圖， 在本實驗中，如該圖所示，將具有矩形狀光強度分布的雷 射光LI、L2 ( KrF雷射所輸出的脈衝雷射光）照射在於藍 寶石基板上形成有GaN材料層的工件來進行。 將雷射光L 1、L2相重疊領域中的雷射光的強度，相對 GaN材料層的分解臨限値VE ( 870mJ/cm2)改變爲105%、 -23- 201216333 110%、115%、120%來進行照射，而對剝離後的材料層的 表面進行調查。 在第 7 圖（b-1) 、 （b-2) (b-3) 、 （b-4)中顯示將 相重疊領域中的雷射光強度相對分解臨限値VE，分別改變 爲105%、110%、115%、120%時之剝離後的材料層的表面 〇 如第7圖（b-1) 、（b-2) (b-3)所示，相對分解臨 限値V E，在相重疊領域中的雷射光的強度爲1 〇 5 %、1 1 0 % 、1 1 5%時，剝離後的材料層的表面狀態良好，並未發現髒 污、傷等對發光特性造成不良影響者。相對於此，若將雷 射光的強度相對分解臨限値VE形成爲120%時，如第7圖（ b-4 )所示，剝離後的材料層的表面狀態係形成有多數如 黑色污垢般的髒污。 其中，雖在第7圖中未顯示，但確認出相對分解臨限 値VE，在重疊領域中的雷射光的強度爲1〇〇 %以下時，亦 在重疊照射雷射光的領域，會在GaN材料層發生未分解部 分。 但是，在第7圖所示例中，係使用具有矩形狀光強度 分布的雷射光LI、L2，此時，無法如第8圖（a)所示調整 在重疊領域中的雷射光的強度，在重疊領域中的雷射光的 強度的調整係必須藉由調整各雷射光LI、L2的強度來進行 〇 相對於此，將雷射光LI、L2的光強度分布（光束輪廓 )如前述第3圖所示，藉由形成爲具有朝圓周方向平緩地 ⑧ -24- 201216333 擴展的邊緣部LE的形狀，來調整雷射光L 1、L2的照射間 隔（或工件的移動速度），且調整上述邊緣部LE的相重疊 程度，藉此可隨意地調整重疊部分中的雷射光的強度。 第8圖（b-Ι)係雷射光LI、L2的重疊量爲適正的情形 ，且爲適當調整照射間隔（或工件的移動速度）的情形， 如該圖（b-2 )所示，剝離後的材料層的表面狀態良好， 並未發現如髒污、傷等對發光特性造成不良影響者。 第8圖（c-1)係雷射光LI、L2的重疊量大，重疊領域 中的雷射光的強度相對分解臨限値VE爲超過1 1 5 %的情形 ，如該圖（c-2 )所示，剝離後的材料層的表面狀態係形 成有多數如黑色污垢般的髒污。 此外，將雷射光107藉由第4圖所示的雷射光學系統40 ，以在第3圖所示剖面中，具有接續朝圓周方向平緩地擴 展的邊緣部LE而在頂點具有平坦面的大致梯形狀的光強度 分布的方式進行成形，藉此當將第9圖所示之雷射光照射 在GaN層102時，可緩和在雷射光的照射領域的邊緣部中進 行急劇的雷射剝蝕的情形。 因此，緩和GaN層102分解時因急劇發生N2氣體所造 成的過量應力施加於GaN層1 02的情形，而可確實減低對剝 離後的GaN層102發生裂痕。 此外，在本發明中，雷射光係以被照射在GaN層102相 鄰接的照射領域的雷射光成爲適當的重疊度的方式相重疊 。藉此，被照射在GaN層1 02的雷射光的各照射領域的邊緣 部的雷射光的能量由於使GaN層102剝離，故爲充分，可使 -25- 201216333201216333 VI. Description of the Invention: [Technical Field] The present invention relates to irradiating a material layer formed on a substrate with laser light in a manufacturing process of a semiconductor light emitting element formed by a compound semiconductor, thereby This material layer is decomposed and is peeled off by the substrate (hereinafter referred to as laser peeling) and a laser peeling method. In particular, the present invention relates to the field of laser light irradiation on a workpiece at one time, and irradiates the laser light by superimposing the respective laser light irradiated on the adjacent irradiation field on the workpiece, thereby irradiating the material layer from the substrate. Stripped laser stripping method and laser stripping device. In the manufacturing process of a semiconductor light-emitting device formed of a GaN (gallium nitride)-based compound semiconductor, a GaN-based compound crystal layer formed on a sapphire substrate is irradiated by the back surface of the sapphire substrate. The technique of laser stripping for laser stripping is known. For example, Patent Document 1 discloses a technique in which a GaN layer is formed on a sapphire substrate, and laser light is irradiated from the back surface of the sapphire substrate to decompose GaN forming the GaN layer, thereby peeling the GaN layer from the sapphire substrate. There are records. However, in order to form a GaN-based compound crystal layer formed on the sapphire substrate, the laser beam is irradiated by the back surface of the sapphire substrate to perform separation, and the irradiation is required to decompose the GaN-based compound into Ga and N2. Laser light with an illumination energy above the limit is extremely important. -5-201216333 Here, when laser light is irradiated, N2 gas is generated by decomposition of GaN. Therefore, shear stress is applied to the GaN layer, and cracks may occur at the boundary portion of the field of irradiation of the laser light. For example, as shown in Fig. 1, if the irradiation area of the 1st emission of the laser light is square, there is a problem that the boundary of the GaN layer 1 1 1 in the field of laser light irradiation is cracked. In particular, when a device is formed using a GaN-based compound crystal layer having a thickness of several μm or less, the GaN-based compound crystal layer does not have sufficient strength to withstand shear stress caused by N2 gas generation, and is easy. A crack has occurred. Further, not only the GaN-based compound crystal layer, but also the crack propagates in the crystal layer formed thereon, and the element itself is damaged, causing a problem in forming a minute-sized element. In order to solve this problem, Patent Document 2 discloses a technique of forming a slab for separating a GaN layer formed on a sapphire substrate in correspondence with a wafer of a semiconductor light-emitting element, and performing laser irradiation. In the stripping process, the boundary is used to alleviate residual stress occurring at the interface between the sapphire substrate and the GaN layer. According to this document, the GaN layer is divided into small areas so that the influence due to residual stress from the surroundings is minimized, and in addition, the small field itself has only minimal residual stress, thereby reducing the GaN layer in the laser peeling. Broken. As described above, when the laser detachment process is performed on the GaN layer formation boundary (the wafer separation boundary line: the dicing line), it is preferably as shown in Patent Document 2. As shown in Fig. 13, the laser light is irradiated in such a manner that the edge portion of the irradiation field of the laser light is in conformity with the boundary. This is based on the fact that although the illumination fields of the respective laser light 8 -6 - 201216333 necessarily overlap the respective end portions, if the irradiation fields of the respective laser lights are on the surface of the GaN layer (ie, the portion other than the boundary) When overlapping, the energy of the laser light irradiated in the overlapping region becomes excessively large, and thus there is a possibility that the GaN layer is adversely affected. However, if a boundary is formed in the GaN layer, in order to alleviate the residual stress, the width of the boundary must be increased to some extent. However, the number of wafers of the semiconductor light-emitting device taken by one sapphire substrate is increased. Reduced problems. Then, when the GaN layer forms a boundary, it is necessary to precisely align the irradiation field of the laser light with the GaN layer formed on the sapphire substrate so that the edge portion of the irradiation region of the laser light coincides with the boundary. Therefore, when the width of the boundary is reduced, it is difficult to accurately align the edge portion of the irradiation field of the laser light on the boundary formed on the GaN layer, and the configuration of the device not only for alignment is complicated. It has also become difficult to carry out its operation/management. Further, each time the wafer size of the semiconductor light-emitting element is different, the alignment must be performed, which causes a problem that the laser peeling process is extremely complicated. On the other hand, Patent Document 3 discloses a technique in which the boundary of the GaN layer is not formed as described above, but the purpose of reducing the damage of the GaN layer is as shown in FIG. 1 for the sapphire substrate 121 and The irradiation region 123 of the interface of the crystal layer 122 of the GaN-based compound forms the laser light 124 in a linear shape, and the sapphire substrate 121 is irradiated to the back surface of the sapphire substrate 121 while being vertically moved in the longitudinal direction of the laser light 124. The laser light 124. In this document, it is described that the laser beam 124 is formed so as to have a line width equal to or lower than the resolution of the optical system 201216333. As shown in FIG. 12, the light intensity distribution in the linear direction of the laser light 124 has a peak at substantially the center. The peak is formed gently toward the edge portion. According to this document, the laser light 1 24 is formed as described above, and thus it is not performed in the field of irradiation of the edge portion in the line direction of the laser light 1 24 when the laser light 1 24 is irradiated onto the crystal layer 1 22 . Sharp laser ablation. Therefore, when the crystal layer 122 belonging to the GaN layer is decomposed, there is no case where N2 is sharply generated, so that excessive stress is not applied to the crystal layer 122, and cracking of the crystal layer 12 2 and the elements formed thereon can be reduced. . However, the present inventors have examined the laser peeling process disclosed in Patent Document 3, and as a result, it has been confirmed that the effect of reducing the damage caused by the crystal layer belonging to the GaN layer is insufficient. [PRIOR ART DOCUMENT] [Patent Document 1] Japanese Patent Publication No. 2001-501768 (Patent Document 2) Japanese Patent Publication No. 2007-534164 (Patent Document 3) JP-A-2003-168820 (Invention) In particular, the inventors of the present invention have confirmed that the crystal layer formed on the sapphire substrate is oriented perpendicular to the longitudinal direction of the laser beam formed in a line shape according to Patent Document 3. In the direction of the movement, the movement speed of the sapphire substrate and the irradiation interval of the pulsed laser light intermittently irradiated are appropriately changed, and the laser light formed by the linear 8 -8 - 201216333 is irradiated onto the crystal layer, and as a result, the GaN layer belonging to the crystal layer is formed. A crack has occurred. The present invention has been made in order to solve the above problems, and an object of the present invention is to provide a crystal layer (hereinafter referred to as a material layer) which is not formed on a substrate, and which can be peeled off from the substrate. Laser stripping method and laser stripping device. Further, the second object of the present invention is to provide a material layer which is not damaged by the sufficient laser energy required to peel the material layer from the substrate, and which does not occur in the material layer. Then, in the case of a problem such as a substrate, a laser peeling method and a laser peeling device which can peel the material layer from the substrate can be used. (Means for Solving the Problem) In the laser detachment, a sapphire substrate (hereinafter referred to as a workpiece) or a laser source on which a material layer is formed is generally scanned, and the field of irradiation of the laser light to the workpiece is changed at all times. The material layer is irradiated with laser light. This is based on the fact that it is difficult to make the field of illumination of the laser light emitted from the laser source equal to the size of the workpiece. Therefore, the edge portions of the irradiation fields of the adjacent laser light on the workpiece are necessarily overlapped, but it is extremely important to overlap each of the laser lights in the laser stripping process. This will be explained using Fig. 2 . In the laser stripping process, a laser source that emits pulsed laser light is used to illuminate the laser light in such a manner that the field of illumination of the laser light changes from time to time. In other words, when the laser beam s 1 is irradiated with the laser beam s 1 in the irradiation field s 1 - 201216333, the field S 2 is irradiated with the laser beam by irradiating the workpiece or the laser source. At this time, the respective edge portions of the irradiation areas S 1 and S 2 of the pulsed laser light overlap. Here, in the field ST in which the respective edge portions of the irradiation areas S1 and S2 overlap, the irradiation amount of the pulsed laser light irradiated to each of the areas of the irradiation areas S1 and S2 is not integrated for the following reason. This is based on the fact that when the irradiation field is moved from S 1 to S2 after irradiating the irradiation field S 1 , the time required for the temperature of the GaN of the irradiation field S1 to fall to the room temperature level is much shorter than that of the irradiation field by S1. Since the time until the time S2 is moved, the temperature of the field S1 is in a state of being lowered to the room temperature level. As a result of the review by the simulation of the present inventors, the time required for the temperature of the GaN in the irradiation region S 1 to fall to the room temperature level is estimated to be within 100 microseconds. It is assumed that the irradiation field S2 is irradiated with the laser light in a state where the temperature of the irradiation area S 1 has been lowered to the room temperature level, and the field ST in which the irradiation areas S 1 and S2 overlap is also only by the laser light irradiated to the irradiation area S2. Heat it. As described above, in the field ST in which the irradiation areas SI and S2 overlap, the irradiation amount of the pulsed laser light irradiated to the respective irradiation areas S1 and S2 is not integrated, and therefore it is necessary to be irradiated in the fields S1, S2. The pulsed laser light of various fields overlaps in the energy field beyond the decomposition threshold of the material layer. On the other hand, it is confirmed that the intensity of the respective pulsed laser light in the field ST in which the respective edge portions of the irradiation regions S1 and S2 overlap each other is excessively large with respect to the decomposition threshold required to peel the material layer from the substrate. When the material layer occurs on the substrate, it is followed by a bad situation. 8 -10- 201216333 This is forbidden to be in the same field, because the intensity of the pulsed laser light is irradiated twice, and the material layer peeled off from the substrate is irradiated with the second pulsed laser light. . It is known from experiments and the like that the intensity of the laser light in the field in which the respective laser beams overlap each other is relatively constant 値 VE' required to peel the material layer from the substrate to form VExl. 15 or less is appropriate. Therefore, in order to avoid the problem of the subsequent adhesion of the substrate and the material layer as described above, it is preferable that the intensity of the laser light in the field in which the respective laser beams overlap is not excessive. Here, 'the intensity (maximum 値) of the laser light in the field where the laser light overlaps)/[decomposition threshold VE] is defined as the degree of overlap T, so that the material layer formed on the substrate is not damaged. And the material layer is actually peeled off from the substrate. Preferably, the degree of overlap T is formed to be 1ST. Further, in order to avoid the subsequent adhesion of the substrate and the material layer, it is preferably formed as TS1. 15. As described above, in the present invention, the above problem is solved as follows (1) A laser peeling method in which pulsed laser light is irradiated by the substrate on which a material layer is formed on a substrate, and the substrate is irradiated with a laser stripping method in which the material layer is peeled off from the substrate by the interface of the material layer, wherein the pulsed laser light changes the irradiation field to the workpiece at a time, and each of the adjacent ones of the workpieces is irradiated Irradiation is performed in such a manner that the fields overlap, and the size of each of the overlapping pulsed laser beams is greater than the energy of the decomposition threshold required to peel the material layer from the substrate. (2) In the above (1), the intensity of the laser light irradiated in the field in which the respective laser beams of the respective irradiation regions adjacent to each other in the -11 - 201216333 are overlapped, and the material layer is relatively The decomposition threshold 値 VE required for the substrate peeling is formed as VExl. 15 or less. (3) In the above (1) and (2), the workpiece is sequentially executed: the first transport operation that is transported in the first transport direction, and the second transport that is transported in the direction orthogonal to the transport direction of the first transport operation. The transport operation: the third transport operation that is transported in a direction that is different from the transport direction of the first transport operation by 180°, and sequentially irradiates the pulsed laser light to each of the illumination regions. (4) in the laser stripping apparatus for performing the above-described laser peeling, forming pulsed laser light emitted from a laser source, and providing a laser optical system having a projection lens that is irradiated onto the workpiece, the light incident surface of the workpiece being It is arranged in such a manner that the optical axis direction of the aforementioned laser light does not coincide with the focal position of the aforementioned projection lens. (Effects of the Invention) According to the laser peeling method of the present invention, the following effects can be expected. (1) Since the laser light irradiated to the adjacent illumination field on the workpiece overlaps in the energy field exceeding the decomposition threshold required to decompose the material layer, the laser light is superimposed in each other. In the field of irradiation, sufficient laser energy for stripping the material layer from the substrate is supplied, so that the material layer formed on the substrate is not damaged, and the material layer can be reliably peeled off from the substrate. (2) the intensity of the laser light to be irradiated in the field in which the respective laser beams of the adjacent irradiation fields overlap, and the decomposition threshold required for the material layer to be peeled off from the above-mentioned 8-12-201216333 substrate値VE, formed as V Ε χ 1 . Below 15, the disadvantages of the substrate and the material layer can be avoided. (3) the light incident surface of the workpiece is disposed so as not to coincide with the focal position of the projection lens in the optical axis direction of the laser light, whereby the beam profile of the pulsed laser light irradiated to the workpiece can be formed as The gradual shape (the illuminance distribution of the peripheral portion of the pulsed laser light to be irradiated is formed into a shape in which the peak portion is gently lowered toward the edge portion). Thereby, by adjusting the irradiation interval of the pulsed laser light (when the workpiece is transported at a constant speed) or adjusting the conveyance speed of the workpiece (the irradiation interval of the pulsed laser light is constant), it is possible to change the field in which the respective laser beams overlap. The intensity of each laser light. [Embodiment] Fig. 1 is a view showing a schematic diagram of a laser stripping process according to an embodiment of the present invention. As shown in the figure, in the present embodiment, the laser peeling treatment is carried out as follows. The workpiece 3 on which the material layer 2 is formed on the substrate 1 through which the laser light is transmitted is placed on the workpiece stage 31. The workpiece stage 31 on which the workpiece 3 is placed is placed on a transport mechanism 32 such as a conveyor, and is transported at a predetermined speed by the transport mechanism 32. The workpiece 3 is conveyed along with the workpiece stage 31 in the direction of the arrow ABC in the drawing, and is irradiated with the pulsed laser light L emitted from a pulse laser source (not shown) through the substrate 1. The workpiece 3 is formed by forming a material layer 2 of a GaN (-13-201216333 gallium nitride)-based compound on the surface of the substrate 1 made of sapphire. The substrate 1 may be a material layer which can form a GaN-based compound well, and transmits a laser beam for decomposing a GaN-based compound material layer at a desired wavelength. In the material layer 2, a GaN-based compound is used, and high-output blue light is efficiently outputted with a low input energy. The laser light should be appropriately selected in accordance with the substrate 1 and the material constituting the material layer peeled off from the substrate 1. When the material layer 2 of the GaN-based compound is peeled off from the substrate 1 of sapphire, for example, a KrF (fluorene fluoride) excimer laser having a wavelength of 248 nm can be used. The optical energy of the laser wavelength of 248 nm is located in the energy gap of GaN (3. 4 e V ) between the energy gap of sapphire (9 · 9 e V ). Therefore, laser light having a wavelength of 248 nm is preferable because the material layer of the GaN-based compound is peeled off from the sapphire substrate. Next, the laser peeling treatment of the embodiment of the present invention will be described using Figs. 1 and 2 . Fig. 2 is a view showing a state in which the laser light L is irradiated on the workpiece 3. Fig. 2(a) shows a method of irradiating the laser light to the workpiece 3, Fig. 2(b) shows an enlarged view of the X portion of Fig. 2(a), and Fig. 2(b) shows the workpiece 3 An example of a cross section of the light intensity distribution of the laser light to be irradiated in each of the irradiation fields. Among them, the solid line on the workpiece 3 shown in Fig. 2 is only intended to show the field of illumination of the laser light. The workpiece 3 is repeatedly conveyed in the direction of the arrows HA, HB, and HC shown in FIG. 2 by the transport mechanism 32. The laser light L is irradiated on the back surface of the substrate 1 of sapphire, and is irradiated on the interface between the substrate 1 and the material layer 2. The shape of the laser light L is formed into a substantially square shape. -14- 201216333 As shown in the first and second figures, the workpiece 3 is sequentially executed in accordance with the size of the workpiece itself: the first transport operation Η A that is transported in the direction of the arrow A in Fig. 1; The second distance of the distance S (the direction of the arrow C in the first figure) that is transmitted in the direction perpendicular to the transport direction of the first transport operation HA (the direction of the arrow C in the first figure) The transport operation HB; and the third transport operation HC transported in the direction of the arrow B in the first diagram. The conveyance directions of the first conveyance operation HA and the third conveyance operation HC are different by 180°. Here, the optical system of the laser light is kept in a fixed state and is not transported. That is, only the workpiece 3 is conveyed while the optical system of the laser light is fixed, whereby the irradiation field of the laser light L in the workpiece 3 is as indicated by the arrow of Fig. 2, according to S 1 to S 1 2 The order is relatively constant at all times. Next, the laser peeling treatment of the embodiment of the present invention will be more specifically described. In the embodiment shown in Fig. 2, the workpiece 3 has a circular shape, but the irradiation field of the laser light is formed into a substantially square shape, and a laser irradiation method in the square-shaped irradiation field as shown above will be described. As shown in Fig. 2, the workpiece 3 is conveyed in the HA direction of Fig. 2, and each of the four irradiation fields of SI, S2, S3, and S4 is irradiated with laser light for one time and four times in total. It is the first transport operation. Then, since the laser light is irradiated onto the next irradiation region S5 of the workpiece 3, the workpiece 3 is conveyed toward the HB direction of Fig. 2 . This is the second transfer operation. The distance that the workpiece 3 is transported in the direction of the arrow HB is equal to the distance from the field of illumination corresponding to 1 shot (1 pulse) of the pulsed laser light minus the distance obtained after the overlap field ST of -15-201216333. 3 is conveyed in the HC direction of Fig. 2, and faces the six irradiation fields of S5, S6, S7, S8, S9, and S10, and irradiates the laser light once every six times. This is the third transfer operation. Regarding the other irradiation fields of the workpiece 3, the workpiece 3 is also conveyed in the above-described series of steps, thereby irradiating the laser light over the entire area of the workpiece 3. The irradiation field of the laser light is relatively moved in the order of SI, S2, and S3 as shown in Fig. 2, but the respective irradiation fields are, for example, 0. 5mmx〇. 5mm, the area is 0. 25mm2. On the other hand, the area of the workpiece 3 is 4560 mm 2 . That is, the irradiation fields S 1 , S 2 , and S 3 of the laser light are much smaller than the workpiece area. In the laser stripping process of the present embodiment, the laser light that is smaller than the irradiation area of the workpiece 3 is scanned toward the direction of the arrows A and B shown in FIG. 1 (that is, the left and right direction of the workpiece), and is faced to the workpiece 3. Irradiation. In contrast to the embodiment of the present invention, it is also possible to maintain an optical system that fixes the workpiece and transports the laser in accordance with the above-described transport operations HA to HC. Simply put, if the field of illumination of the laser light on the workpiece changes with the moment of the moment, the workpiece can be irradiated with laser light. Here, in the laser stripping process of the present invention, as shown in FIG. 2(b), each of the laser beams intermittently irradiated in the irradiation areas SI, S2, and S3 in which the laser light is adjacent to each other The ends of the wide direction are irradiated on the workpiece 3 in such a manner as to overlap each other. The laser light L is pulsed laser light and is intermittently irradiated on the workpiece 3. In the irradiation fields S1, S2, S3 of the workpiece 3, the width of the overlapping of the laser light is, for example, 0. 1 mm. The pulse interval of the laser light is in consideration of the conveyance speed of the workpiece 3 and the width of the overlapping field ST of the laser light irradiated by the radiation field S 1 , S 2 , S 3 , ... which are adjacent to the workpiece 3 on the workpiece 3 - 16 16 16 333 Make appropriate settings. Basically, the pulse interval of the laser light is determined in such a manner that no laser light is irradiated on the workpiece before the workpiece 3 is moved to the next irradiation field. That is, the pulse interval of the laser light is set to be longer than the time required for the workpiece 3 to move by a distance equivalent to the irradiation area of one shot of the laser light. For example, the conveying speed of the workpiece 3 is 100 mm/sec, and the width of the overlapping field ST of the laser light is 0. At 1 mm, the pulse interval of the laser light is 0. 004 seconds (250Hz). Fig. 3 is a view showing the light intensity distribution of the laser light irradiated to the workpiece in such a manner that the fields S1 and S2 adjacent to each other in the workpiece 3 shown in Fig. 2 overlap, which is shown in Fig. 2(b). A-a' line profile. In the figure, the vertical axis indicates the intensity (energy enthalpy) of the laser light that is irradiated to each of the irradiation areas of the workpiece, and the horizontal axis indicates the conveyance direction of the workpiece. Further, 'L1, L2' indicate the profile of the laser light that is irradiated to the irradiation areas S1 and S2 of the workpiece, respectively. Here, the laser light LI and L2 are not irradiated simultaneously, but after the laser light L1 is irradiated, the laser light L2 is irradiated after being separated by one pulse. In this example, as shown in Fig. 3, the cross sections of the laser beams L1 and L2 are formed as edge portions LE which are smoothly extended in the circumferential direction, and have a substantially trapezoidal shape at the vertex (peak energy PE). . Next, as shown by the broken line in Fig. 3, the laser light LI and L2 overlap each other in the energy field exceeding the decomposition limit 値 VE required for decomposing the material layer of the GaN-based compound and peeling off the sapphire substrate. -17-201216333 In other words, the intensity (energy 値) CE of the laser light at the intersection C of the laser light L1 and L2 in the light intensity distribution of each of the laser beams is performed so as to exceed the enthalpy of the decomposition threshold VE. set up. As described above, when the irradiation field is irradiated with S1 to S2 after irradiating the irradiation field S1 of FIG. 2, the temperature of the field S1 is lowered to the room temperature level, so it is assumed When the temperature of the irradiation region S1 has been lowered to the room temperature level, the irradiation field S2 is irradiated with the laser light, and the irradiation amount of the pulsed laser light irradiated to the respective irradiation fields S1 and S2 is not integrated. The intensity of the respective pulsed laser light in the field where the intensity CE of the laser light at the intersection C of the laser light L1 and L2, that is, the laser light is superimposed, is a mode that exceeds the enthalpy of the above-described decomposition threshold VE The setting is such that sufficient laser energy for stripping the material layer from the substrate is provided without causing damage to the material layer formed on the substrate, and the material layer can be reliably peeled off from the substrate. That is, the degree of overlap T defined in the preceding paragraph is preferably formed to be 1 ST . Here, with respect to the relative movement amount of the workpiece 3 and the laser light, the pulse interval of the laser light is adjusted in advance so that the laser light irradiated to the irradiation region adjacent to the workpiece 3 overlaps as described above. In the embodiment shown in the figure, since the material layer is GaN, the decomposition threshold is 500 to 1 500 00/cm2. The decomposition threshold VE system must be set for each material constituting the material layer. Here, as described above, it is understood that the laser light L1 and L2 overlap with the energy leader exceeding the resolution threshold VE, but as will be described later, in order to avoid the defect of the substrate 8 -18-201216333 and the material layer. It is necessary to set the ratio of the magnitudes of the decomposition thresholds VE of the respective overlapping laser beams to be appropriate, specifically, to the above-described decomposition threshold VE, to become VE xl . It is advisable to set the following 15 ways. In the embodiment of Fig. 3, the intensity (energy enthalpy) CE of the laser light at the intersection C of the laser light L1 and L2 in the light intensity distribution of each of the laser light is relative to the peeling of the material layer from the substrate. Need to break down the threshold 値 VE to become VExl. Set by 15 or less. That is, the aforementioned degree of overlap T is formed to be TS1. 15 is appropriate. Fig. 4 is a view showing a laser peeling apparatus of an embodiment of the present invention. In the figure, the laser stripping device 10 is provided with a laser source 20 that emits the pulsed laser light, a laser optical system 40 for forming laser light into a predetermined shape, and a workpiece for mounting the workpiece 3. The table 31; the transport mechanism 32 that transports the workpiece stage 31; and the control unit 33 that controls the irradiation interval of the laser light generated by the laser source 20 and the operation of the transport mechanism 32. The optical system 40 includes a lenticular lens 41. a mirror 43 that reflects the laser light toward the direction of the workpiece; a mask 44 for shaping the laser light into a predetermined shape; and a projection lens 45 that condenses the laser light L passing through the mask 44 on the workpiece 3. . A workpiece 3 is disposed in front of the optical system 40. The workpiece 3 is placed on the workpiece stage 31. The workpiece stage 31 is placed on the transport mechanism 32 and transported by the transport mechanism 32. Thereby, the workpiece 3 is sequentially conveyed in the direction of the arrows A, B, and C shown in the first drawing, and the irradiation field of the laser light in the workpiece 3 is constantly changed. The control unit 3 3 controls the pulsed laser light generated at the laser source 20 such that the overlapping degree of the respective laser light irradiated to the field of the illuminating -19-201216333 adjacent to the workpiece 3 becomes a desired enthalpy. Pulse interval. The laser light L generated by the laser source 20 is, for example, a KrF excimer laser which emits ultraviolet rays having a wavelength of 248 nm. For laser sources, ArF lasers or Y A G lasers can also be used. Here, the light incident surface 3A of the workpiece 3 may be disposed on the far side in the optical axis direction of the laser light, or vice versa, in the optical axis direction of the laser light, compared to the focus F of the projection lens 45. The light incident surface 3 A of the workpiece 3 is disposed closer to the projection lens 45 than the focal point F of the projection lens 45. As described above, by arranging the light incident surface 3 A of the workpiece 3 so as not to coincide with the focal point F of the projection lens 45, the beam profile having the laser light LI, L2 as shown in Fig. 3 can be obtained. The edge portion LE is gently lowered and has a laser light having a trapezoidal light intensity distribution. The laser light L generated by the laser source 20 passes through the lenticular lenses 41, 42, the mirror 43, and the mask 44, and is then collected by the projection lens 45 on the workpiece 3. The laser light incident on the light incident surface 3A of the workpiece 3 by the projection lens 45 is in the cross section shown in Fig. 3, and has a flat surface LE that smoothly spreads in the circumferential direction and has a flat surface at the vertex. The shape of the trapezoidal light intensity distribution is shaped. The light intensity distribution of each of the laser beams irradiated so as to overlap the irradiation area adjacent to the workpiece is preferably a trapezoidal shape as described above, but may not necessarily be a trapezoidal shape. Fig. 5 is a view showing the light intensity distribution of the laser light irradiated on the workpiece -20-201216333 Other embodiments. The light intensity distribution of the laser light shown in Fig. 5(a) is formed in a substantially mountain shape in which the peak portion is at the center and has an edge portion LE which smoothly expands after the peak. The light intensity distribution of the laser light can be appropriately changed by adjusting the distance between the focal point F of the projection lens 45 shown in Fig. 4 and the light incident surface 3A of the workpiece 3. The light intensity distribution of the laser light is closer to the distance between the focal point F of the projection lens 45 and the light incident surface 3A of the workpiece 3, and is formed into a clear rectangular shape, with the light incident from the focal point F of the projection lens 45 and the workpiece 3. The farther the distance of the face 3A is, the more smoothly the edge is formed and formed into a mountain shape. Further, as shown in Fig. 5(b), the light intensity distributions of the laser beams L1 and L2 may be formed in a rectangular shape. At this time, the intensity of the laser light in the field in which the laser beams L1 and L2 overlap each other (the intensity of the laser light at the intersection of the laser light L1 and L2, at this time, the peak of the laser light L1 Corresponding) is set to CE 'The above overlap degree T is calculated by T = CE / [decomposition threshold 値 VE]. At this time, the intensity CE of the laser light at the intersection of the laser light L1 and L2 is greater than the decomposition threshold VE required to peel the material layer from the substrate, and the relative decomposition threshold VE is formed to form It is suitable for VE X 1 · 1 5 or less. Here, the effects obtained by performing the laser lift-off process of the present embodiment will be described using Figs. 3 and 6 . Fig. 3 is a view showing the light intensity distribution of the laser light used in the laser stripping method of the present embodiment. Fig. 6 is a view showing the light intensity distribution of the laser light for comparison therewith. LI and L2 in Fig. 3 and Fig. 6 show laser light that is irradiated to the irradiation areas of SI and S2 shown in Fig. -21 - 201216333. Regarding the influence of the degree of overlap of the laser light irradiated on the adjacent irradiation area of the workpiece on the material layer peeled off from the substrate, the third and sixth figures are used for comparative review. The laser light LI and L2 shown in Fig. 3 have a substantially trapezoidal light intensity distribution having a flat portion extending toward the circumferential direction and having a flat surface at the apex, and an energy field exceeding the decomposition threshold VE. In the laser light LI and L2, the degree of overlap T becomes an appropriate 値 (1 or more, 1. The way within 15) overlaps. Therefore, in the laser peeling method of the embodiment of Fig. 3, when the laser light is irradiated on the surface of the material layer 2 on the interface side with the substrate 1 to decompose the GaN constituting the material layer 2, the N2 gas does not suddenly occur. The situation. Further, the laser peeling method of the embodiment of Fig. 3 is based on the fact that the energy of the laser light irradiated by the overlapping field ST in which the laser light L1 and L2 overlap in the second drawing is not excessively insufficient and becomes optimum energy. The disadvantage of the material layer 2 and the substrate 1 being avoided is avoided, and the material layer 2 can be surely peeled off from the substrate 1. Actually, the surface state of the material layer after peeling off the laser light of the embodiment shown in Fig. 3 is very beautiful. No contamination or damage is caused to cause adverse effects on the light-emitting characteristics. On the other hand, when the laser light of the comparative example of FIG. 6( a ) is irradiated onto the workpiece, the respective light intensity distributions of the laser light L1 and L2 cross each other in the energy region lower than the decomposition threshold VE, so In the workpiece shown in Fig. 2, there is a problem that the amount of laser light that is irradiated to the overlapping area ST of the laser light L1 and L2 is insufficient. Actually, when the laser beam of the comparative example shown in Fig. 6(a) is irradiated to the -22-201216333, the undecomposed field of GaN which constitutes the material layer is formed, and the material layer cannot be sufficiently peeled off from the substrate. The undecomposed field of GaN coincides with the overlapping field ST in which the laser light L1 and L2 overlap in the workpiece. On the other hand, when the laser beam shown in the comparative example of Fig. 6(b) is irradiated onto the workpiece, the degree of overlap T between the laser light L1 and L2 is excessively large, so that it is present in the workpiece shown in Fig. 2. A problem of laser light that irradiates excess energy to the overlapping area ST of the laser light L1 and L2. As shown in Fig. 7 (b-4), which will be described later, the surface state of the material layer after peeling off the laser light of the comparative example shown in Fig. 6(b) is actually formed on the surface. Black dirt-like dirt. In this case, it is considered that the laser light having a large energy is irradiated twice in the same portion, and the material layer peeled off from the substrate at a time is irradiated with the second laser light, and the sapphire component constituting the substrate adheres. The black stain formed on the surface of the material layer as described above adversely affects the luminescence characteristics. In order to confirm the above effects, the effect of the degree of overlap of the laser light in the irradiation field in which the laser light is superimposed on the material layer after the peeling is experimentally performed. Fig. 7 is a view showing the result. Fig. 7(a) is a view showing the light intensity distribution of the laser light in the adjacent area used for the experiment, and in this experiment, as shown in the figure, the laser light LI having a rectangular light intensity distribution is shown. L2 (pulse laser light output by KrF laser) is irradiated on a workpiece on which a GaN material layer is formed on a sapphire substrate. The intensity of the laser light in the overlapping field of the laser light L 1 and L2 is changed to 105%, -23-201216333 110%, 115%, 120% with respect to the decomposition threshold VE (870 mJ/cm 2 ) of the GaN material layer. Irradiation was performed, and the surface of the material layer after peeling was investigated. In Figures 7(b-1), (b-2), (b-3), and (b-4), it is shown that the intensity of the laser light in the overlapping field is relatively decomposed to the threshold 値VE, which is changed to 105%, The surface of the material layer after peeling at 110%, 115%, and 120% is as shown in Fig. 7 (b-1) and (b-2) (b-3), and the relative decomposition threshold 値 VE is in the phase. When the intensity of the laser light in the overlap region is 1 〇 5 %, 1 10 0 %, and 1 1 5%, the surface state of the material layer after peeling is good, and no adverse effect on the luminescence characteristics such as dirt or damage is found. . On the other hand, when the intensity of the laser light is 120% with respect to the decomposition threshold VE, as shown in FIG. 7(b-4), the surface state of the material layer after the peeling is formed like a black stain. Dirty. However, although it is not shown in FIG. 7, it is confirmed that the relative decomposition threshold 値 VE, when the intensity of the laser light in the overlapping region is 1% or less, is also in the field of overlapping irradiation of laser light, and will be in GaN. The undecomposed portion of the material layer occurs. However, in the example shown in Fig. 7, the laser light L1 and L2 having a rectangular light intensity distribution are used. In this case, the intensity of the laser light in the overlapping region cannot be adjusted as shown in Fig. 8(a). The adjustment of the intensity of the laser light in the overlapping field must be performed by adjusting the intensity of each of the laser light L1, L2, and the light intensity distribution (beam profile) of the laser light L1, L2 is as shown in FIG. It is shown that the irradiation interval (or the moving speed of the workpiece) of the laser light L 1 , L2 is adjusted by forming the shape of the edge portion LE which is extended in the circumferential direction from 8 to 24 to 201216333, and the edge portion LE is adjusted. The degree of overlap, whereby the intensity of the laser light in the overlapping portion can be arbitrarily adjusted. Fig. 8 (b-Ι) is a case where the amount of overlap of the laser light LI and L2 is correct, and the irradiation interval (or the moving speed of the workpiece) is appropriately adjusted, as shown in the figure (b-2), peeling off The surface of the material layer was in good condition, and no adverse effects such as dirt and damage on the luminescent properties were observed. Fig. 8(c-1) shows the case where the amount of overlap of the laser light LI and L2 is large, and the intensity of the laser light in the overlapping field is more than 11.5 % relative to the decomposition threshold VE, as shown in the figure (c-2). As shown, the surface state of the material layer after peeling is formed with a lot of dirt such as black dirt. In addition, the laser light 40 shown in FIG. 4 has a flat portion which is smoothly extended in the circumferential direction and has a flat surface at the apex in the cross section shown in FIG. By forming the light intensity distribution of the trapezoidal shape, when the laser light shown in FIG. 9 is irradiated onto the GaN layer 102, the sharp laser ablation in the edge portion of the irradiation field of the laser light can be alleviated. . Therefore, when the GaN layer 102 is decomposed, excessive stress caused by the rapid occurrence of the N2 gas is applied to the GaN layer 102, and cracking of the GaN layer 102 after peeling can be surely reduced. Further, in the present invention, the laser light is superimposed so that the laser light irradiated to the irradiation region adjacent to the GaN layer 102 has an appropriate degree of overlap. Thereby, the energy of the laser light irradiated to the edge portion of each of the irradiation regions of the laser light of the GaN layer 102 is sufficient to cause the GaN layer 102 to be peeled off, so that it can be made -25-201216333
GaN層102由藍寶石基板101確實剝離。 接著說明可適用上述雷射剝離處理的半導體發光元件 的製造方法。以下係使用第9圖來說明藉由GaN系化合物材 料層所形成的半導體發光元件的製造方法。 在結晶成長用的基板係使用可透射雷射光而使構成材 料層的氮化鎵（GaN )系化合物半導體作結晶成長的藍寶 石基板。 如第9圖（a)所示，在藍寶石基板101上，係使用例 如有機金屬氣相成長法（MOCVD法），迅速形成由GaN系 化合物半導體所構成的GaN層102。接著，如第9圖（b )所 示，在GaN層1Q2的表面係層積有作爲發光層的n型半導體 層103與ρ型半導體層104。例如，以η型半導體而言，係使 用摻雜有矽的GaN，以ρ型半導體而言，係使用摻雜有鎂的 GaN。接著，如第9圖（c)所示，在ρ型半導體層104上塗 佈有焊料105。接著，如第9圖（d)所示，在焊料105上安 裝支持基板1 06。支持基板1 06係由例如銅與鎢的合金所構 成。接著，如第9圖（e)所示，由藍寶石基板101的背面 側朝向藍寶石基板101與GaN層102的界面照射雷射光107， 而將GaN層102分解，藉此剝離藍寶石基板101。在由藍寶 石基板101剝離後的GaN層102的表面，藉由蒸鍍形成作爲 透明電極的ITO108，在ITO108的表面安裝電極109。 【圖式簡單說明】 第1圖係說明本發明之實施例的雷射剝離處理槪要的 ⑧ -26- 201216333 槪念圖。 第2圖係顯示雷射光被照射在工件的態樣圖。 第3圖係顯示在本發明之實施例中，重疊照射在工件 之彼此相鄰接的領域S 1、S2的雷射光的光強度分布圖。 第4圖係本發明之實施例的雷射剝離裝置的槪念圖。 第5圖係顯示雷射光的光強度分布的其他實施例的圖 〇 第6圖係顯示用以與本實施例的雷射光的光強度分布 作比較的比較例的圖。 第7圖係顯示對雷射光的重疊度對剝離後的材料層所 造成的影響進行調查後的實驗結果的圖。 第8圖係說明可藉由將雷射光的光強度分布形成爲平 緩的形狀，來調整重疊部分中的雷射光的強度的圖。 第9圖係說明可適用雷射剝離處理的半導體發光元件 的製造方法的圖。 第1 〇圖係顯示雷射光的1發射的照射領域爲正方形狀 時的圖。 第1 1圖係說明使線狀雷射光一面朝與雷射光的長邊方 向呈垂直方向移動，一面由基板的背面照射的習知技術的 圖。 第12圖係顯示第11圖所示之習知技術中的雷射光的光 強度分布圖。 【主要元件符號說明】 -27- 201216333 1 :基板 2 :材料層 3 :工件 1 〇 :雷射剝離裝置 2 0 :雷射源 3 1 :工件載台 32 :搬送機構 3 3 :控制部 40 :雷射光學系統 41、42 :柱狀透鏡 43 :反射鏡 44 :遮罩 45 :投影透鏡 1 〇 1 :藍寶石基板 102 : GaN層 1〇3 : n型半導體層 104 : ρ型半導體層 1 0 5 :焊料 106 :支持基板 1 〇 7 :雷射光 108:透明電極（ΙΤΟ) 1 09 :電極 1 1 〇 : 1發射的照射領域 1 1 1 : GaN層 ⑧ -28- 201216333 1 12 :交界 1 2 1 :藍寶石基板 1 2 2 :結晶層 123 :照射領域 1 2 4 :雷射光 A、B、C :方向 C E :雷射光的強度 F :焦點 L、LI、L2:雷射光 LE :邊緣部 PE :峰値能量 VE :分解臨限値 -29-The GaN layer 102 is surely peeled off by the sapphire substrate 101. Next, a method of manufacturing a semiconductor light-emitting device to which the above-described laser lift-off treatment can be applied will be described. Hereinafter, a method of manufacturing a semiconductor light-emitting device formed of a GaN-based compound material layer will be described using FIG. In the substrate for crystal growth, a sapphire substrate in which a gallium nitride (GaN)-based compound semiconductor constituting a material layer is crystal-grown is used to transmit laser light. As shown in Fig. 9(a), on the sapphire substrate 101, a GaN layer 102 made of a GaN-based compound semiconductor is rapidly formed by, for example, an organometallic vapor phase growth method (MOCVD method). Next, as shown in Fig. 9(b), an n-type semiconductor layer 103 and a p-type semiconductor layer 104 as light-emitting layers are laminated on the surface of the GaN layer 1Q2. For example, in the case of an n-type semiconductor, GaN doped with germanium is used, and in the case of a p-type semiconductor, GaN doped with magnesium is used. Next, as shown in Fig. 9(c), the p-type semiconductor layer 104 is coated with solder 105. Next, as shown in Fig. 9(d), the support substrate 106 is mounted on the solder 105. The support substrate 106 is made of an alloy such as copper and tungsten. Next, as shown in Fig. 9(e), the sapphire substrate 101 is peeled off by irradiating the glare substrate 107 with the ray layer 107 by illuminating the GaN layer 102 from the back surface side of the sapphire substrate 101 toward the interface between the sapphire substrate 101 and the GaN layer 102. On the surface of the GaN layer 102 which was peeled off from the sapphire substrate 101, ITO 108 as a transparent electrode was formed by vapor deposition, and an electrode 109 was attached to the surface of the ITO 108. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a summary of the laser detachment treatment of the embodiment of the present invention 8-26-201216333. Fig. 2 is a view showing a state in which laser light is irradiated on a workpiece. Fig. 3 is a view showing a light intensity distribution of laser light which is superimposed on the fields S1, S2 adjacent to each other in the workpiece in the embodiment of the present invention. Fig. 4 is a view showing a laser peeling apparatus of an embodiment of the present invention. Fig. 5 is a view showing another embodiment of the light intensity distribution of the laser light. Fig. 6 is a view showing a comparative example for comparison with the light intensity distribution of the laser light of the present embodiment. Fig. 7 is a graph showing experimental results after investigating the influence of the degree of overlap of the laser light on the material layer after peeling. Fig. 8 is a view for explaining the adjustment of the intensity of the laser light in the overlapping portion by forming the light intensity distribution of the laser light into a gentle shape. Fig. 9 is a view for explaining a method of manufacturing a semiconductor light-emitting device to which laser lift-off treatment can be applied. The first diagram shows a diagram in which the illumination field of the 1 emission of the laser light is square. Fig. 1 is a view showing a conventional technique in which linear laser light is moved in a direction perpendicular to the longitudinal direction of the laser light and is irradiated on the back surface of the substrate. Fig. 12 is a view showing the light intensity distribution of the laser light in the conventional technique shown in Fig. 11. [Description of main component symbols] -27- 201216333 1 : Substrate 2 : Material layer 3 : Workpiece 1 〇: Laser peeling device 2 0 : Laser source 3 1 : Workpiece stage 32 : Transport mechanism 3 3 : Control unit 40 : Laser optical system 41, 42: lenticular lens 43: mirror 44: mask 45: projection lens 1 〇1: sapphire substrate 102: GaN layer 1〇3: n-type semiconductor layer 104: p-type semiconductor layer 1 0 5 : Solder 106 : Support substrate 1 〇 7 : Laser light 108 : Transparent electrode (ΙΤΟ) 1 09 : Electrode 1 1 〇 : 1 Irradiated field of emission 1 1 1 : GaN layer 8 -28- 201216333 1 12 : Junction 1 2 1 : sapphire substrate 1 2 2 : crystal layer 123 : irradiation field 1 2 4 : laser light A, B, C: direction CE: intensity of laser light F: focus L, LI, L2: laser light LE: edge portion PE: peak値Energy VE: Decomposition threshold 値-29-