1287309 九、發明說明·· 【發明所屬之技術領域】 本發明是有關於一種雷射剝離方法，特別是指一種用 於製造氮化鎵基半導體垂直結構元件的雷射制離方法。 【先前技伊】 在藍光發光二極體（light emitiing diode，led)的製作上 ，一般基板的選擇是使用藍f石⑷2〇3)基板，用以成長出 較雨品質之氮化鎵基（GaN_based)蟲晶薄膜，然而藍寶石基 ，之導電性及導熱性不良，限制傳統藍光led僅能採用正 負電極在基板同-側之橫向結構，如此一來，除了減少元 件的發光面積之外，更因電流擁擠效應（current c卿㈣ effect)使元件導通電阻及順向壓降增加。 為了改°上述缺失，目前的做法是使用藍寶石基板成 長GaN基磊晶薄膜後，，接著利用例如電鍍的方法成長一金 屬薄膜’或是利用晶圓接合（wafer b〇nding)的方式，在㈣ 基蟲晶薄臈上形成—新的基板，再使用雷射剝離法（ι_ 肋，來移除藍寶石基K㈣基蟲晶薄膜最後是位於 。亥新的基板上。然而傳統的雷射剝離法移除藍寶石基板， 係利用雷射光地毯式地掃瞒處理整塊藍寶石基板，因此， 、曰將正層GaN基薄膜轉移至新基板上，於元件製程中， :、:頁經由後續微影、蝕刻或切割製程，始能定義出位在新 土 ^上的GaN基薄膜用於發光的晶粒之形狀與尺寸，造成 製程步驟繁複且費時之缺失。 【發明内容】 1287309 即在提供一種可以定義出氮化BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a laser lift-off method, and more particularly to a laser lift-off method for fabricating a gallium nitride-based semiconductor vertical structural component. [Previous technology] In the production of light emitting diodes (LED), the general substrate is selected using a blue f stone (4) 2 〇 3) substrate to grow a rain-quality GaN-based ( GaN_based) film, but sapphire-based, poor conductivity and thermal conductivity, limiting the traditional blue LED can only use the lateral structure of the positive and negative electrodes on the same side of the substrate, so in addition to reducing the light-emitting area of the component, The on-resistance and forward voltage drop of the component increase due to the current crowding effect (current c. In order to change the above-mentioned defects, the current practice is to grow a GaN-based epitaxial film using a sapphire substrate, and then grow a metal film by, for example, electroplating or by wafer bonding, in (4) The base crystal is formed on a thin crucible - a new substrate, and then a laser stripping method (ι_ rib to remove the sapphire-based K(tetra)-based insect crystal film is finally located on the new substrate. However, the conventional laser stripping method In addition to the sapphire substrate, the entire sapphire substrate is processed by a laser-polished broom, so that the positive GaN-based film is transferred to the new substrate, and in the component process, the page is etched through subsequent lithography. Or the cutting process can initially define the shape and size of the GaN-based film on the new soil for illuminating the crystal grains, resulting in complicated and time-consuming process steps. [Summary] 1287309 is to provide a definition Nitriding
(b)設置光罩：將一呈 因此，本發明之目的， / :準備一轉換基板，在該轉換基板 導體層，以及一支持基板。 具有鏤空區的光罩，鄰近該試片單 元之轉換基板設置。 一 （C)…、光·將雷射光穿過光罩之鏤空區並照射該試片單 ^。此時位於轉換基板上的氮化鎵基半導體層具有對應鎮 空區的晶粒區，以及位在晶粒區周圍的分隔區。 (d)加熱··將受雷射光照射後的試片單元加熱。 。（e)剝離·將該轉換基板連同氮化鎵基半導體層之分隔 區，一起剝離氮化鎵基半導體層之晶粒區以及支持基板， 亦卩此日守轉換基板與分隔區是結合在一起，而晶粒區是 與支持基板結合在一起。 藉由上述雷射光搭配光罩使用，使GaN基半導體層在 —即皇立農基.裁—上馮—戒—間*备晶务 一_—匕基Ba粒與支持基板所形成的半導體結構，應用 於發光二極體或其他垂直結構元件上，可以省略傳統雷射 剝離法後續的微影'蝕刻等步驟，故確實具有簡化製程步 驟、節省時間等優點。 本發明較佳地包含一項位在步驟（b)之前的步驟（f)，所 述步驟（f)是將轉換基板拋光，以減少雷射光透過轉換基板 1287309 後造成的能量損耗。 上述轉換基板通常是藍寶石基板，而 η -電鑛於GaN基半導體層上的金屬薄 夺基板則是 合形成於半導體層上的石夕晶圓。 5疋利用晶圓接 本發明之光罩的鏤空區 ^ 疋0形、矩形等形狀，實 施時不以光罩之形狀為限。 在轉換A柘盥Γ Μ # 田射先疋透過該鏤空區照射 在轉換基板與GaN基铸體層介面上，故 成之晶粒區，其大小、报业H^ t “ J $狀疋約略與雷射光的截面相同， 換曰之’晶粒區的形狀亦是由 丄 尤卓之鏤空區的形狀所定義 而成。且利甩雷射光配合氺罝銘 ’ 一心 先罩移動，或疋單獨移動該試月 早凡後’可㈣GaN基半導體層上的適當位置，雷 光，成間隔之晶粒區’所述晶粒區的間距，則是由兩次 擊發雷射光的位置定義而成。亦即，當晶粒區為長寬皆為 则，左右的正方形時，而雷射光是每移動遍哗擊發一 次，則晶粒區之間距即為60μηι。 此外，本發明亦可以利用更換光罩，或者在雷射光射 出光罩之鏤空區後，配合透鏡組合產生聚焦功效，改變雷 射光截面之大小，形成不同尺寸的晶粒區。 本發明之雷射光是採用準分子雷射（excimer lase〇，雷 射光的波長小於或等於355nm。f GaN基半導體層之晶粒 區接受雷射光照射後，由於雷射光照射加溫，於晶粒區上 鄰近轉換基板之一側會發生解離反應，當溫度達到9〇(rc 〜1000°C時，GaN產生解離反應的反應式為：(b) Setting a reticle: a purpose of the present invention, /: preparing a conversion substrate, a conductor layer on the conversion substrate, and a support substrate. A reticle having a cutout is disposed adjacent to the conversion substrate of the test strip unit. One (C)..., light. The laser light is passed through the hollow area of the reticle and the test piece is illuminated. The gallium nitride based semiconductor layer on the conversion substrate at this time has a grain region corresponding to the void region, and a spacer region located around the grain region. (d) Heating · The test piece unit irradiated with the laser light is heated. . (e) stripping the strip substrate of the gallium nitride-based semiconductor layer and the supporting substrate together with the separation region of the conversion substrate and the gallium nitride-based semiconductor layer, and also the bonding substrate and the separation region are combined And the grain region is combined with the support substrate. By using the above-mentioned laser light with a reticle, the semiconductor structure formed by the GaN-based semiconductor layer in the support substrate is formed by the GaN-based semiconductor layer. It can be applied to the light-emitting diode or other vertical structural components, and the subsequent lithography 'etching steps of the conventional laser stripping method can be omitted, so it has the advantages of simplifying the process steps and saving time. The present invention preferably comprises a step (f) prior to step (b) of polishing the conversion substrate to reduce the energy loss caused by the passage of the laser light through the conversion substrate 1287309. The conversion substrate is usually a sapphire substrate, and the metal thin substrate on which the η-electrode is deposited on the GaN-based semiconductor layer is formed on the semiconductor layer. 5. The wafer is connected to the hollow region of the reticle of the present invention, such as a 疋0 shape or a rectangular shape, and is not limited to the shape of the reticle. In the conversion A柘盥Γ Μ #田射先疋 illuminates the interface between the conversion substrate and the GaN-based casting layer through the hollow region, so the size of the grain region, the size of the newspaper, and the newspaper H^t “J $ 疋The cross section of the laser light is the same, and the shape of the 'grain area' is also defined by the shape of the hollow area of the 丄 卓 卓 卓 卓 卓 甩 。 。 。 。 。 。 。 。 。 。 。 。 。 ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' The test month is as follows: the appropriate position on the (four) GaN-based semiconductor layer, the lightning, the interval between the grain regions, and the spacing of the grain regions are defined by the position of two shots of laser light. When the grain area is both long and wide, the left and right squares, and the laser light is fired once per movement, the distance between the die areas is 60 μm. In addition, the present invention can also utilize the replacement mask, or After the laser light is emitted from the hollow area of the reticle, the lens combination is combined to produce a focusing effect, and the size of the laser light section is changed to form a grain area of different sizes. The laser light of the present invention uses an excimer laser (excimer lase〇, thunder) The wavelength of the light is less than Equal to 355 nm. After the grain region of the f GaN-based semiconductor layer is irradiated with laser light, due to the irradiation of the laser light, a dissociation reaction occurs on the side of the grain region adjacent to the conversion substrate, when the temperature reaches 9 〇 (rc ～ 1000) At °C, the reaction formula of GaN to generate dissociation reaction is:
GaN~^Ga^y2N2{g) 1287309 其中氮氣會填塞於GaN基半導體層與轉換基板間，使 GaN基半導體層之晶粒區易於與轉換基板分離。 一般而言，當雷射光能量密度為4〇〇 mJ/cm2時，即可 達到使GaN.基半導體層產生解離反應所需之溫度，亦即為 9曰⑼。C〜麵。，雷射光通過藍寶石基板日夺會產生能 量衰減，以厚度4 450 _之藍寶石基板為例，雷射光透過 藍寶石基板後，其能量將衰減4〇〜5〇%，因此必需將雷射光 輸出能量設定在750 mJ/cm2以上。故·本發明所需要的雷射 光之能量密度，是依據轉換基板之厚度與雷射光脈衝時間 適田m。以厚度為鳩〜450 μηι之藍寳石基板為例，當 脈衝時間為20〜40如時，則雷射光之能量密度設定為500田〜 850 mJ/cm2 〇 。而本發明之加熱步驟’只需要將試片單元加熱至川〜 40 C，即可輕易地將試片單元之藍寶石轉換基板剝除，並 於支持基板上留下所需要的形狀與尺权㈣基半導體層 :之，留在支持基板上的為GaN基半導體層之晶㈣ 支持基板上形成數條縱橫交錯並位在晶粒區之間的切. 二㈣切割道之寬度即為相鄰日日日粒區的間距，故亦是 兩-人擊發雷射光的位置所定義而成。 【實施方式】 以下==前述及其他技術内容、特點與功效，在 清楚的呈現。 “η例的坪細說明中，將可 [實施例一] 8 1287309 如圖1、2、3所示，本發明雷射剝離方法之第一較佳 實施例包含以下步驟··GaN~^Ga^y2N2{g) 1287309 wherein nitrogen gas is interposed between the GaN-based semiconductor layer and the conversion substrate, so that the grain regions of the GaN-based semiconductor layer are easily separated from the conversion substrate. In general, when the laser light energy density is 4 〇〇 mJ/cm 2 , the temperature required for the dissociation reaction of the GaN.-based semiconductor layer can be reached, that is, 9 曰 (9). C ~ face. Laser light passes through the sapphire substrate to generate energy attenuation. Taking a sapphire substrate with a thickness of 4 450 _ as an example, after the laser light passes through the sapphire substrate, its energy will be attenuated by 4〇~5〇%, so it is necessary to set the laser light output energy. Above 750 mJ/cm2. Therefore, the energy density of the laser light required by the present invention is based on the thickness of the conversion substrate and the laser light pulse time. Taking a sapphire substrate having a thickness of 450~450 μηι as an example, when the pulse time is 20 to 40, the energy density of the laser light is set to 500 to 850 mJ/cm2 〇 . However, the heating step of the present invention only needs to heat the test piece unit to ～40 C, and the sapphire conversion substrate of the test piece unit can be easily peeled off, and the desired shape and the ruler are left on the support substrate (4) a semiconductor layer: a crystal of a GaN-based semiconductor layer remaining on the support substrate. (4) A plurality of criss-crossings are formed on the supporting substrate and are cut between the crystal grain regions. The width of the second (four) cutting track is the adjacent day. The spacing of the daily grain area is defined by the position of the two-person firing laser light. [Embodiment] The following == The foregoing and other technical contents, features and effects are clearly presented. In the detailed description of the η example, the first embodiment of the laser stripping method of the present invention is as shown in Figs. 1, 2 and 3, and the first preferred embodiment of the laser stripping method of the present invention comprises the following steps:
(1)進行步驟11製備一試片單元2:準備一轉換基板 21 ’該轉換基板21具有間隔的一第一面211，以及一第二 面212 ’再於轉換基板21之第一面211上形成一 G aN基半 導體層22，接著於GaN基半導體層22上形成一支持基板 23 ’故所述試片單元2包括該轉換基板2丨、GaN基半導體 層22，以及支持基板23。 在本實施例中，該轉換基板21是採用藍寶石基板，而 该支持基板23是一層電鍍於GaN基半導體層22上的金屬 薄膜。 (2) 進行步驟12將轉換基板21拋光：使用一圖未示出 的拋光機將藍寶石基板拋光，使藍寶石基板達到一適當厚 度、力為3 00〜450 μιη左右，以利於進行後續步驟。在本 實施例中，該藍寳石基板的厚度為4〇〇μηι。 (3) 進行步驟π設置光罩3 :將該試片單元2放置在一 未气出的雷射機台之卫作平台上，並使轉換基板^之 2。面212朝向上，且於轉換基板21上方設置一個具有鏤 31的光罩3。本實施例的光罩3的鏤空區31為矩形， 其長寬皆為3mm。 革心、進行步驟14照光：使用波長為248_的KrF準分 “ ^光4 m脈衝時間為38ns，輸出能量為75〇 ⑽，使雷射光4 .穿過光罩3之 抓力忠當 早J之鏤工區31，並透過一個 °又 3與試片單元2之間’且圖中未示出的十倍聚焦 9 1287309 透鏡組合’照射該試片單元2，該GaN基半導體層22即形 • 成對應鏤空區31 ,並受雷射光4照射的晶粒區221，以及 位在晶粒區221周圍的分隔區222。 由於本實施例之雷射光4是透過透鏡組合聚焦，所以 雷射光4聚焦後的截面積的長及寬，皆為光罩3之鏤空區 31的長、寬的十分之一，亦即為3〇〇μιη，故基半導體 層22的晶粒區221大致上亦為矩形，尺寸為3〇〇μηιχ3〇〇μιη 一 〇 • ^ (5) 剷後左右地移動試片單元2，且每距離36〇^m，擊 \ 發一次雷射光4，使GaN基半導體層22之晶粒區221為間 ^ 12又置’且晶粒區221之間隔為όΟμιη。接受照射後的晶粒 區221在鄰近轉換基板21之一側，亦即於該第一面21丨上 產生分解反應，所述分解反應的產物223為以與N2(g)。 (6) 進行步驟15加熱：將該照射雷射光4後的試片單 兀2置於一圖中未示出的加熱墊上，溫度控制在％〜4〇 % • 間。’ (7) 續如步驟16剝離：加熱後即可將該轉換基板2丨連 、 同GaN基半導體層22之分隔區222，一起剝離GaN基半導 ★ 體層22之晶粒區221以及支持基板23，換言之，此時轉換 基板21與分隔區222是結合在-起，而晶粒區221是如圖 4所不’與支持基板23結合在-起，且支持基板23上形成 ，條縱橫交錯並位在晶粒區221之間的切割道231，該等切 231之寬度即為相鄰晶粒區221的間距，亦為$叫爪。 ()進行步驟17移除分解反應之產物223 ··將鹽酸與水 10 1287309 以1 : 1的比例混合來調配出稀鹽酸水溶液，將上述支持基 板23與位於其上的晶粒區221，浸泡在該稀鹽酸水溶液中 ’時間維持3 0秒左右’以洗去殘留的反應產物Ga，而得到 乾淨的GaN基晶粒區221。 [實施例二](1) Step 11 is performed to prepare a test strip unit 2: a conversion substrate 21 is prepared. The conversion substrate 21 has a first surface 211 spaced apart, and a second surface 212' is further disposed on the first surface 211 of the conversion substrate 21. A GaN-based semiconductor layer 22 is formed, and then a support substrate 23 is formed on the GaN-based semiconductor layer 22. The test strip unit 2 includes the conversion substrate 2, the GaN-based semiconductor layer 22, and the support substrate 23. In the present embodiment, the conversion substrate 21 is a sapphire substrate, and the support substrate 23 is a metal thin film plated on the GaN-based semiconductor layer 22. (2) Performing step 12 to polish the conversion substrate 21: polishing the sapphire substrate using a polishing machine not shown, so that the sapphire substrate reaches a suitable thickness and a force of about 300 to 450 μm to facilitate the subsequent steps. In this embodiment, the sapphire substrate has a thickness of 4 μm. (3) Step π is performed to set the reticle 3: the test strip unit 2 is placed on a turret of a laser machine that is not vented, and the substrate is switched. The face 212 faces upward, and a mask 3 having a weir 31 is disposed above the conversion substrate 21. The hollowed-out area 31 of the reticle 3 of the present embodiment is rectangular, and its length and width are both 3 mm. Gravity, step 14 illumination: use KrF quasi-minute of wavelength 248_ " ^ 4 m pulse time is 38 ns, output energy is 75 〇 (10), so that the laser light 4 through the mask 3 grasping force early The working area 31 of J is irradiated with the test piece unit 2 through a combination of a lens and a ten-fold focus 9 1287309 lens (not shown) between the test piece unit 2, and the GaN-based semiconductor layer 22 is a pattern 221 corresponding to the hollow region 31 and irradiated by the laser light 4, and a separation region 222 positioned around the grain region 221. Since the laser light 4 of the present embodiment is focused through the lens combination, the laser light is 4 The length and width of the cross-sectional area after focusing are one tenth of the length and width of the hollow region 31 of the mask 3, that is, 3 〇〇μιη, so that the grain region 221 of the base semiconductor layer 22 is substantially Also rectangular, the size is 3〇〇μηιχ3〇〇μιη 一〇• ^ (5) Move the test piece unit 2 left and right behind the shovel, and each distance 36〇^m, hit a laser light 4 to make GaN-based semiconductor The grain region 221 of the layer 22 is interposed and the interval between the die regions 221 is όΟμιη. The grain region 221 after receiving the irradiation is A decomposition reaction occurs on one side of the conversion substrate 21, that is, on the first surface 21, and the product 223 of the decomposition reaction is heated in step 15 with N2 (g). (6): irradiating the laser light After 4, the test piece 2 is placed on a heating pad not shown in the figure, and the temperature is controlled between % and 4%%. ' (7) Continued as in step 16: the substrate 2 can be heated after heating The junction region 222 of the GaN-based semiconductor layer 22 and the support substrate 23 are stripped together with the separation region 222 of the GaN-based semiconductor layer 22, in other words, the conversion substrate 21 and the separation region 222 are combined at this time. The die region 221 is formed on the support substrate 23 as shown in FIG. 4, and is formed on the support substrate 23, and the strips are vertically and horizontally staggered and positioned between the die regions 221, and the cut lines 231 are The width is the spacing of the adjacent grain areas 221, which is also called the claw. () Step 17 removes the product of the decomposition reaction 223 ·· Mix hydrochloric acid and water 10 1287309 in a ratio of 1:1 to prepare dilute hydrochloric acid In the aqueous solution, the support substrate 23 and the crystal grain region 221 located thereon are immersed in the dilute hydrochloric acid aqueous solution' The time is maintained for about 30 seconds to wash away the residual reaction product Ga to obtain a clean GaN-based crystal grain region 221. [Embodiment 2]
如圖5所示，實施例二之步驟大致與該實施例一相同 ’所形成的晶粒區221的大小亦為3〇0μηιχ3〇〇μπι，本實施 例與貫施例一不同之處在於：本實施例之試片單元2的移 動距離為550μηι，故形成於GaN基半導體層22上的晶粒區 221的間距，亦即支持基板23之切割道231的寬度為 250μηι 〇 [實施例三] 如圖ό所示，實施例三之步驟大致與該實施例一相同 ，不同之處在於：本實施例使用具有不同大小之鏤空區 的光罩3,並於支持基板上製成四個大致呈正方形但是邊長 不同的晶粒區221，該等晶粒區221之邊長由大至小分別為 :360μηι、„ 30〇μηι、230μιη、90μπι。 由以上說明得知，藉由雷射光4搭配光罩3使甩，使 ㈣基半導體層22在剝離該轉換基板21之同時，即於支 ^基板23上形成間隔之晶粒區22卜此㈣ 導體結構，應用在發光二極體或其他垂 直、““件上，可以省略傳統雷射剝 _、崎步驟才能定義“aN基晶粒的缺== 月具有製程步驟簡單、節省時間、降低製作成本之優點 11 73〇( 並且有利於應用在發光二極體元件的製作上。 准以上所述者，僅為本發明之較佳實施例而已，當不 :以此限疋本發明實施之範圍，即大凡依本發明申請專利 :圍及^明說明内容所作之簡單的等效變化與修飾，皆仍 屬本發明專利涵蓋之範圍内。 【圖式簡單說明】 圖1疋本發明用於製造氮化鎵基半導體垂直結構元件 的雷射剝離方法的流程圖； 一圖2.是一立體圖，顯示本發明之一第一較佳實施例的 一先罩、-雷射光’以及—試片單元的設置狀態； 圖3是該第一較佳實施例的各步驟的加工示意圖； 曰圖4,是該第一較佳實施例所得結果的圖片，圖中顯示 晶粒區邊長為300μιη，切割道寬度為; 圖5是本發明之一第二Μ# f _ 平乂1土貫施例所得結果的圖片， 圖中顯示晶粒區邊長為3〇〇μπι τ刀剖道見度為250μΐΉ ;及 圖6是本發明之一第三較佳每 门丄 平1土只加例所得結果的圖片， 圖中晶粒區邊長由大至小分別為 刀〜马 36〇_、3〇〇 23〇 90μηι。 r 12 1287309 •【主要元件符號說明】 11 〜17 —步驟 222… •…为Pw £ 2,…… •…試片單元 223… •…分解反應的產物 21..... —轉換基板 23 …，· •…支持基板 211… …·第一面 231… •…切割道 212… —第二面 3*…… —光罩 22…… *…氮化叙基半導體層 3 1 …*· …·鏤空區 221… 日日粒£ 4……. •…雷射光As shown in FIG. 5, the steps of the second embodiment are substantially the same as those of the first embodiment. The size of the die region 221 formed is also 3〇0μηιχ3〇〇μπι. The difference between this embodiment and the first embodiment is: The distance of the die unit 2 of the present embodiment is 550 μm, so that the pitch of the die regions 221 formed on the GaN-based semiconductor layer 22, that is, the width of the dicing streets 231 of the support substrate 23 is 250 μm 〇 [Example 3] As shown in FIG. 3, the steps of the third embodiment are substantially the same as those of the first embodiment, except that the present embodiment uses the photomasks 3 having different sizes of hollowed-out regions, and four substantially formed on the support substrate. The grain areas 221 having squares but different side lengths, the side lengths of the grain areas 221 are: 360μηι, „30〇μηι, 230μιη, 90μπι, respectively. It is known from the above description that the laser light 4 is matched with The photomask 3 is used to make the (four)-based semiconductor layer 22 form the spaced-grained grain region 22 on the support substrate 23 while peeling off the conversion substrate 21, and the (four) conductor structure is applied to the light-emitting diode or other vertical , "" on the piece, can be omitted The system can define the “aN-based grain defect== month. It has the advantages of simple process steps, time saving and low production cost. 11 73〇 (and is beneficial for the production of LED components). The above is only the preferred embodiment of the present invention, and is not limited to the scope of the present invention, that is, the patent application according to the present invention: the simple content of the description and the content of the description The effect variation and modification are still within the scope of the present invention. [Simplified Schematic] FIG. 1 is a flow chart of a laser stripping method for fabricating a gallium nitride-based semiconductor vertical structural component according to the present invention; Is a perspective view showing a state of a hood, a laser light, and a test strip unit of a first preferred embodiment of the present invention; and FIG. 3 is a schematic view of the processing of the steps of the first preferred embodiment. 4 is a picture of the result of the first preferred embodiment, showing a grain length of 300 μm and a scribe line width; FIG. 5 is a second Μ# f _ 乂1 of the present invention. Picture of the results obtained from the application of the example, It is shown that the side length of the crystal grain region is 3〇〇μπι τ, and the cross-sectional visibility is 250 μΐΉ; and FIG. 6 is a picture of the third preferred example of the first best case of the first flat soil in the present invention. The length of the grain area is from knife to horse 36〇_, 3〇〇23〇90μηι. r 12 1287309 • [Main component symbol description] 11~17 — Step 222... •... is Pw £ 2,...... • The test piece unit 223... • The product of the decomposition reaction 21..... The conversion substrate 23 ..., • The support substrate 211... The first surface 231... The cutting channel 212... The second surface 3 *...... —Photomask 22... *...Nitrided semiconductor layer 3 1 ...*· ...· cutout area 221... 日日粒£ 4....... •...Laser light
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