201232804 六、發明說明： 【發明所屬之技術領域】 本發明係關於一種在太陽能電池(solar cell)燒錄 識別石馬（identification)方法，特別是指以雷射於太陽能 電池表面燒錄識別碼的方法。 【先前技術】 近年來，由於環保意識的抬頭和其他能源逐漸的枯 竭’使得世界各國開始重視再生能源的利用。再生能源 包括：太陽能、風能、水力能或生質能等來源無所匱乏 的資源。而台灣地處亞熱帶，曰照豐富，因此在台灣， 利用太陽能電池(solar cell)作為太陽能源的開發，使太陽能 的光電轉換效率提高，為現今各產業研究的焦點。 為了監控每一片晶圓的製程狀況，達到進一步提高 產品良率的目的，在傳統半導體積體電路的製程中，將 識別碼燒錄在晶圓上的技術已經相當成熟。然而，在太 陽能電池(solar cell)的製程中’此方面的技術及應用卻 尚未普及。其中一個原因是，若將識別碼燒錄在太陽能 電池的前表面，會增加遮光的效應，而使光電轉換效率 降低，另一個原因是，對於整體製程的成本來說，這並 不符合經濟效益（一片積體電路晶圓的產值約在數百甚 至數仟倍之多大於太陽電池晶圓）。 沒有識別碼’在製備太陽能電池的過程中就無從追 蹤每一片晶圓的製程參數。更有甚者，當太陽能電池良 率出現異常時’很難即時從生產線製程記錄的資料發現 問題所在’也就無從找出對應的改善措施。因此，若每 201232804 一片晶圓能有各自的識別碼，有助於進一步對製程參數 做最佳化的調整。 在公開案號為20070163634的美國專利申請案 中，僅是概括的揭示太陽能電池在完成製程後，將識別 碼印製於太陽能電池的概念，印製的手段包括以雷射、 喷砂或以抗化學腐蝕的油墨印製於太陽能電池表面、背 面或側邊。 而在另一公開案號為20,080,160,648的美國專利 申請案中，則揭示在進行製程前後，分別記錄晶圓表面 的光致螢光影像（photoluminescence)。一旦太陽能電 池的良率出現異常時，係藉由比對不同晶圓的表面影像 來作為識別的方式。然而，要以這種方法辨識出是哪一 片晶圓’比對將非常不容易。尤其自同一晶棒，它的柱 狀長晶特性將使得切割下的晶圓’相鄰兩片晶圓的表面 圖像會非常相似，容易造成判別錯誤。 另外，目前業界太陽能電池生產的速率每曰至少有 12萬片，可以想見，用來儲存圖像的資料庫需要非常 大的容量，更別說是比對了。 為了方便追溯製程紀錄及太陽能電池的測試數 據，有必要發展一種在太陽能電池上燒錄識別碼的技 術，使識別碼刻錄於太陽能電池照射面時，不僅不影響 太陽能電池的光電轉換效率，又容易判讀。 201232804 【發明内容】 有鑒於上述課題，本發明之目的之一在於提供一種 在太陽能電池表面讀寫識別碼的方法，包括：提供一批 次太陽能電池基板的半成品，半成品是指太陽能電池基 板已完成部分或所有製程；及以雷射對太陽能電池基板 吸光面或背面寫入一識別晶片的識別碼，係以雷射針對 識別碼所在區域做熱處理，以改變識別碼所在區域的光 學性質，其中，識別碼無法以肉眼直接辨識，在可見光 以外的光源才能辨識。 所述可見光以外的光源，最好波長大於1100 nm 或小於400 nm。由於識別碼對於可見光的反射率不 高，肉眼難以辨識，因此，判讀識別碼時，係以一紫外 光電荷搞合元件或一遠紅外光電荷粞合元件讀取。或者 以一配備有可見光濾光片的白光讀取裝置來讀取。 識別碼選自圖形記號、數字標記、文字及其任意組 合所組成的群組其中之一種，圖形記號、數字標記或文 字代表太陽能電池基板的測試數據、製程參數或晶圓代 號。同時配合一對照表，可以追溯各別片太陽能電池的 製程參數及/或測試數據。本發明之另一實施例，是將 太陽能電池基板所有的製程履歷及測試結果，整合成一 圖形記號。 本發明之方法不但可以整合於原本的製程中，相較 於前案而言，除了判讀容易之外，又不會降低太陽能電 池光電轉換效率。並且，當太陽能電池的良率下降時， 檢測人員可以依據每一片太陽能電池基板的製程參數 201232804 貝料’進仃分析及查找問題’並適時調整製程參數，來 使太陽能電池的品質最佳化。 【實施方式] 為使本發明之上述目#、特徵和優點能更明顯易 ^下文依本發明於太陽能電池(solar cell)表面讀寫 識別碼的方法，A4· & > 特舉較佳實施例’並配合所附相關圖 Μ作詳、.，田。兒明如下，其中相同的元件將以相同的元件 付號加以說明。201232804 VI. Description of the Invention: [Technical Field] The present invention relates to a method for identifying an identification of a solar cell in a solar cell, in particular, a laser for burning an identification code on a surface of a solar cell. method. [Prior Art] In recent years, due to the rise of environmental awareness and the gradual depletion of other energy sources, countries around the world have begun to pay attention to the use of renewable energy. Renewable energy includes: resources such as solar energy, wind energy, hydropower or biomass energy. Taiwan is located in the subtropical zone and is rich in sunshine. Therefore, in Taiwan, the use of solar cells as solar energy sources has improved the photoelectric conversion efficiency of solar energy, which is the focus of research in various industries today. In order to monitor the process conditions of each wafer and further improve the yield of the product, the technology of burning the identification code on the wafer in the process of the conventional semiconductor integrated circuit is quite mature. However, in the process of solar cells, the technology and application of this aspect have not yet been popularized. One of the reasons is that if the identification code is burned on the front surface of the solar cell, the effect of shading will increase, and the photoelectric conversion efficiency will be lowered. Another reason is that it is not economical for the cost of the overall process. (The output value of a piece of integrated circuit wafer is about hundreds or even several times larger than that of a solar cell wafer). No identification code' has no process parameters to track each wafer during the preparation of the solar cell. What's more, when the solar cell yield is abnormal, it is difficult to find out the problem immediately from the data recorded in the production line process. Therefore, if each wafer has a unique identification code for each 201232804, it will help to further optimize the process parameters. In the U.S. Patent Application Publication No. 20070163634, it is merely a general disclosure of the concept of printing an identification code on a solar cell after the solar cell is completed. The means of printing include laser, sand blasting or resistance. Chemically etched ink is printed on the surface, back or sides of the solar cell. In another U.S. Patent Application Serial No. 20,080,160,648, the disclosure of the entire disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of Once the yield of the solar cell is abnormal, it is identified by comparing the surface images of different wafers. However, it is very difficult to identify which wafer is 'aligned' in this way. Especially from the same ingot, its columnar crystal growth characteristics will make the surface images of the adjacent wafers of the wafer under cutting will be very similar, which is easy to cause discrimination errors. In addition, the current production rate of solar cells in the industry is at least 120,000 per inch. It is conceivable that the database used to store images requires a very large capacity, let alone a comparison. In order to facilitate the traceability of the process record and the test data of the solar cell, it is necessary to develop a technology for burning the identification code on the solar cell, so that when the identification code is recorded on the illuminated surface of the solar cell, the photoelectric conversion efficiency of the solar cell is not affected, and it is easy. Interpretation. 201232804 SUMMARY OF THE INVENTION In view of the above problems, one of the objects of the present invention is to provide a method for reading and writing an identification code on a surface of a solar cell, comprising: providing a semi-finished product of a batch of solar cell substrates, and the semi-finished product means that the solar cell substrate has been completed. Part or all of the process; and writing an identification code of the identification chip to the light absorption surface or the back surface of the solar cell substrate by laser, and performing heat treatment on the area where the identification code is located by the laser to change the optical property of the region where the identification code is located, wherein The identification code cannot be directly recognized by the naked eye, and the light source other than visible light can be recognized. The light source other than the visible light preferably has a wavelength greater than 1100 nm or less than 400 nm. Since the reflectance of the identification code for visible light is not high, it is difficult for the naked eye to recognize. Therefore, when the identification code is interpreted, it is read by an ultraviolet light charge matching element or a far infrared light charge combining element. Or read with a white light reading device equipped with a visible light filter. The identification code is selected from the group consisting of a graphic mark, a digital mark, a text, and any combination thereof, and the graphical mark, digital mark, or text represents test data, process parameters, or wafer code of the solar cell substrate. At the same time, a comparison table can be used to trace the process parameters and/or test data of the individual solar cells. Another embodiment of the present invention integrates all process history and test results of the solar cell substrate into a graphical symbol. The method of the present invention can be integrated not only in the original process, but also in comparison with the previous case, it does not reduce the photoelectric conversion efficiency of the solar cell. Moreover, when the yield of the solar cell is lowered, the inspector can optimize the quality of the solar cell according to the process parameters of each solar cell substrate, 201232804, and the process parameters are adjusted in time to adjust the process parameters. [Embodiment] In order to make the above-mentioned objects, features, and advantages of the present invention more obvious, the method for reading and writing an identification code on a surface of a solar cell according to the present invention is preferably A4· & The embodiment 'and the accompanying drawings are detailed, . It is as follows, in which the same elements will be described by the same component.
請來昭圖1 Λ 、 ΙΑ’本發明實施例中，利用雷射於太陽 :b^池,板10上’形成-識別晶片的識別碼11。值得 /主忍的疋’本發明中以雷射燒錄識別碼11時，係使表 面曰曰粒結構局部繞灼，識別碼11所在區域的光學性質 會隨之改變。 在太陽能電池製程中’一批次太陽能電池基板至少 1依序經過清潔、結構化(texturing)、擴散、絕緣、鍍 优反射層、網印電極及燒結等製程，並進行電性測試。 而本發明之以雷射燒錄識別碼的步驟，可以在 月匕電池基板完成結構化(texturing)的製程後進行。除 選擇，是在太陽能電池基板完成所有的製程及電性更奸 後進行，以一併將測試結果整合至識別碼中。 /則試 又一較佳實施例’是針對具有選擇性射極結 陽能電池，在該批次太陽能電池基板以雷射補助換的太 成選擇性射極結構的製程後，進行燒錄識別碑的 在本發明實施例中，識別碼可以選擇性地燒錄 驟。 電池基板的吸光面或背面 於太陽 能 201232804 本發明實施例_，係使用光波長為532 nm的掺鈥 釩酸釔（Nd:YV04)雷射，燒錄識別碼時所使用的功率僅 有大約5至25W，脈衝頻率大約讣至50kHz，相較於 一般太陽能電池製程中，用來圖案化所使用的雷射脈衝 頻率（大於100kHz)更低。In the embodiment of the present invention, the identification code 11 of the wafer is formed by using a laser on the solar panel. In the present invention, when the identification code 11 is burned by the laser, the surface granule structure is partially burned, and the optical properties of the region where the identification code 11 is located are changed. In the solar cell process, at least one batch of solar cell substrates is sequentially cleaned, texturing, diffused, insulated, plated with reflective layers, screen printed electrodes, and sintered, and electrically tested. The step of laser-burning the identification code of the present invention can be performed after the process of completing the texturing of the moon-shaped battery substrate. In addition to the selection, it is done after the solar cell substrate has completed all the processes and electrical traits, and the test results are integrated into the identification code. A further preferred embodiment is directed to a process with a selective emitter-junction solar cell, after the batch of solar cell substrates is replaced by a laser-assisted elective selective emitter structure. In the embodiment of the present invention, the identification code can be selectively burned. The light absorbing surface or the back surface of the battery substrate is solar energy 201232804. In the embodiment of the present invention, a neodymium-doped yttrium vanadate (Nd:YV04) laser having a wavelength of 532 nm is used, and the power used for burning the identification code is only about 5 Up to 25W, the pulse frequency is about 50 kHz, which is lower than the laser pulse frequency (greater than 100 kHz) used for patterning compared to the general solar cell process.
請參照圖1B，為太陽能電池吸光面經粗糙化之 後，對於不同光波長的反射率。由圖中可以看出，太陽 月匕龟池吸光面對於可見光及紅外線（波長大約4〇〇至 1050 nm)而言’反射率僅有大約1〇%至18。/〇，對光波 長大於1100 nm或小於400 nm(圖16中被圈選的區域) 的反射率至少大於25%。 也就是說，在識別碼所在區域，表面晶粒的結 二雖=改變了 ’但在可見光下’报難直接觀察到差異所 ΐ。在可見光以外的光源下，最好波長大於1100 _ 的區域。換言之，本性質已經被改變 果。而圖2B為圖2A的局^放置^買取識別碼的結 清楚觀察到經過雷射熱處理後，晶二圖=中即可 域。所述的識別碼讀取襄置=生變化的區 件或-遠紅外光電雜合元件， 陽能電池基板=紀錄於太 率幾乎沒有任何影響。 此电池的光電轉換效 識別碼選自圖形記號、數字標記、文字及其任意組 201232804 合所組成的群組其中之一種。而圖形記號、數字標記或 文字可以代表太陽能電池基板的測試數據、製程參數或 晶圓代號。 本發明實施例中，更包括建立一對照表（丨〇〇k-up table)，包含識別碼圖形、數字標記或文字所對應的資 訊。比如：以數字標記代表個別片晶圓的編號，以星形 記號代表製程過程中的異常，或是以英文字母A〜D對 該片太陽能電池測試結果分級等等。整體而言，在該片 太陽能電池基板上紀錄的資訊，可以依照實際製程需求 來做設計。 本發明較佳實施例以圖2A的識別碼為例，圖2A 中的識別碼11為一經過設計的圖形，圖形的不同區域 可以分別代表晶圓編號、測試數據、製程參數等情況。 也就是說，將該片太陽能電池的製程履歷及測試結果全 部整合一個識別碼圖形中，只要針對此圖形進行解碼， 即可追溯該片太陽能電池的製程狀況。 综上所述，本發明所提供的在太陽能電池基板燒錄 識別碼的方法，具有下列優點： (1) 製程參數校正更容易。由於每一片太陽能電池 基板都擁有各自的識別碼，使得每一片太陽能電池基板 在製備過程中的參數可以被記錄及建檔。當太陽能電池 的良率下降時，檢測人員可以依據每一片太陽能電池基 板的製程參數資料，進行分析及查找問題，並適時調整 製程參數，來使太陽能電池的品質最佳化。 (2) 不影響光電轉換效率。由於識別碼所在區域對 可見光的反射率很低，因此，該區域仍然可以吸收太陽 201232804 光來產生載子，對於整體光電轉換效率來說，並無太大 影響。 (3)判讀容易，又不造成系統負擔。本發明中，只 要使用一紫外線或遠紅外線電荷耦合元件，即可讀取識 別碼，不需要如同先前技術一般比對晶圓的表面圖像， 來辨識晶圓，非常方便。另外，資料庫中不需要儲存大 量圖片，只需要儲存對照表即可，因此，不會造成系統 過大的負擔。 本發明雖以較佳實例闡明如上，然其並非用以限定 本發明精神與發明實體僅止於上述實施例。凡熟悉此項 技術者，當可輕易了解並利用其它元件或方式來產生相 同的功效。是以，在不脫離本發明之精神與範疇内所作 之修改，均應包含在下述之申請專利範圍内。 201232804 【圖式簡單說明】 圖1A顯示本發明實施例之具有識別碼的太陽能電池 基板； 圖1B顯示太陽能電池基板吸光面結構化之後對不同 波長的光反射率； 圖2A顯示本發明實施例中，以識別碼讀取裝置所讀取 到的識別碼；及 圖2 B顯示圖2A識別碼的局部放大圖。 【主要元件符號說明】 10 :太陽能電池基板 11 :識別碼 12 :識別碼讀取裝置Please refer to FIG. 1B, which is a reflectance for different light wavelengths after the light absorption surface of the solar cell is roughened. As can be seen from the figure, the reflectance of the solar moon's turtle pool is only about 1% to 18 for visible light and infrared light (wavelength of about 4 〇〇 to 1050 nm). /〇, the reflectance for light wavelengths greater than 1100 nm or less than 400 nm (the circled area in Figure 16) is at least greater than 25%. That is to say, in the region where the identification code is located, the surface grain of the second layer = changed 'but the visible light' is difficult to directly observe the difference. In a light source other than visible light, a region having a wavelength greater than 1100 _ is preferred. In other words, this property has been changed. 2B is the result of the mounting of the identification code of FIG. 2A. It is clearly observed that after the laser heat treatment, the crystal two maps are in the middle field. The identification code reading device = the zone of the change or the far-infrared photoelectric hybrid component, and the solar cell substrate = the recording rate has almost no effect. The photoelectric conversion identification code of this battery is selected from the group consisting of graphic symbols, digital markers, text and any group of 201232804. The graphical mark, digital mark or text may represent the test data, process parameters or wafer designation of the solar cell substrate. In the embodiment of the present invention, a 丨〇〇k-up table is further included, and the information corresponding to the identification code graphic, the digital mark or the text is included. For example, the number of individual wafers is represented by a digital mark, the anomaly during the process is represented by a star mark, or the test results of the solar cell are graded by the letters A to D, and so on. Overall, the information recorded on the solar cell substrate can be designed according to actual process requirements. In the preferred embodiment of the present invention, the identification code of FIG. 2A is taken as an example. The identification code 11 in FIG. 2A is a designed graphic, and different regions of the graphic may respectively represent the wafer number, test data, process parameters, and the like. That is to say, the process history and the test result of the solar cell are integrated into one identification code pattern, and the process state of the solar cell can be traced back by decoding the pattern. In summary, the method for burning an identification code on a solar cell substrate provided by the present invention has the following advantages: (1) Process parameter correction is easier. Since each solar cell substrate has its own identification code, the parameters of each solar cell substrate during preparation can be recorded and documented. When the yield of the solar cell drops, the inspector can analyze and find the problem according to the process parameter data of each solar cell substrate, and adjust the process parameters in time to optimize the quality of the solar cell. (2) Does not affect the photoelectric conversion efficiency. Since the area where the identification code is located has a low reflectance to visible light, the area can still absorb the sun 201232804 light to generate carriers, which has little effect on the overall photoelectric conversion efficiency. (3) It is easy to interpret without causing system burden. In the present invention, it is very convenient to use a UV or far-infrared charge-coupled component to read the identification code without having to compare the surface image of the wafer as in the prior art. In addition, there is no need to store a large number of images in the database, only the comparison table needs to be stored, so there is no excessive burden on the system. The present invention has been described above by way of a preferred embodiment, and it is not intended to limit the spirit of the invention and the inventive subject matter. Anyone familiar with this technology can easily understand and utilize other components or methods to produce the same effect. Modifications made without departing from the spirit and scope of the invention are intended to be included within the scope of the appended claims. 201232804 [Simplified Schematic] FIG. 1A shows a solar cell substrate with an identification code according to an embodiment of the present invention; FIG. 1B shows light reflectance for different wavelengths after structuring a light-absorbing surface of a solar cell substrate; FIG. 2A shows an embodiment of the present invention. The identification code read by the identification code reading device; and FIG. 2B shows a partial enlarged view of the identification code of FIG. 2A. [Description of main component symbols] 10 : Solar cell substrate 11 : Identification code 12 : Identification code reading device
[s] 10[s] 10