201234622 六、發明說明： 【發明所屬之技術領域】 本發明的實施例大體係關於印刷在太陽能電池製造中使 用的基板的方法，該等基板諸如為矽基板。 【先前技術】 太陽能電池是將太陽光直接轉換成電能的光伏器件。光 伏市場最近十年以高於3 0%的年增長率已迅速擴大。一些文 章已經假定在不久的將來源自太陽能電池的世界能源製造 將超過10 GWp。已經估計全部太陽能模組的95%以上是基 於石夕基板的。市場的高增長速度，與充分降低太陽能電力成 本的該需求結合，已經導致了在生產商業可行的高品質太陽 能電池方面的許多挑戰。影響太陽能電池商業可行性的一些 挑戰包括製造成本、太陽能電池性能和製造能力。 太陽能電池通常具有一或多個P_n結。每個p n結都包 括在半導體材料内部的兩個不同區，兩個不同區中一側是P 型區，而另一側是n型區。當太陽能電池的pn結暴露給太 陽光（由源自光子的能量構成）時，借助於光伏效應太陽光 破轉換成電力。太陽能電池產生特定量的電能，並且太陽能 =池層豐在一定尺寸的模組中，.以便傳輸所需量的系統能 戛。利用特定框架和連接器將太陽能模組連接在面板内。太 4 201234622 陽能電池通常由矽基板形成，該等矽基板可為單晶矽基板或 ^曰曰碎基板。典型的太陽能電池包括諸如晶片的硬基板，該 石夕基板的厚度通常小於約〇·3 mn^矽基板通常具有η型矽薄 層，該η型矽薄層在ρ型區上面，該ρ型區形成於基板上。 圖1示意性圖示了由基板i 5〇形成的標準矽太陽能電池 C»薄線或指狀物116設置在基板150的正面（亦即光接收 表面）上。薄線或指狀物116彼此平行，並且薄線或指狀物 116用於收集經由光伏效應產生的電流，並將該電流供應到 集電棒（collector bar)或者接觸匯流條（c〇ntact busbar)，諸如 匯流條114。該匯流條114也設置在太陽能電池c的光接收 表面上，並且該匯流條114設置成與指狀物116垂直並與指 狀物116電接觸。 已經使用絲網印刷將設計印刷在諸如織物或陶瓷的物體 上，並且在電子工業中使用絲網印刷以在基板表面上印刷電 子部件的模型，該等電子部件諸如電接觸或電互連。在現有 技術狀態下製造太陽能電池的方法也使用絲網印刷方法。熟 知的是，通常使用合適的導電膠或接觸膠借助於絲網印刷工 藝來製造太陽能電池的電路和電接觸，該等電路和電接觸通 常為指狀物和匯流條。在一或多個絲網印刷站中進行絲網印 刷’每個電池被支樓在傳送機上的同時移動進出該等絲網印 刷站。該傳送機具有表面或者處理平面，在印刷工藝期間待 處理的太陽能電池被定位在該表面或者處理平面上。 5 201234622 通常’根據太陽能電池的結構，可將太陽能電池劃分成 不同類型，一種類型稱作「背接觸」太陽能電池。背接觸太 陽能電池是用於太陽能電池相反摻雜區域的歐姆接觸被設 置在太陽能電池背部（亦即，非光接收表面）上的太陽能電 池。接觸存在於太陽能電池背面上減少了照射損失，該等照 射損失原本由於在太陽能電池光接收表面上存在金屬接觸 而導致。 一種製造背接觸太陽能電池的方法包括金屬穿孔捲繞技 術（Metal Wrap Through, MWT)技術，該技術將用於相反摻雜 區的兩個外部接觸（或者匯流條）114定位在背面b上，而 將集電結（或者指狀物）定位在正面上。經由集電結或者指 狀物收集在正面F上的電流通過橫穿基板延伸的孔傳導到背 面B。於是，經由定位在太陽能電池背面上的一或多個匯流 條收集電流。以此方式，因為匯流條被定位在太陽能電池的 非照射表面上，因此減少了因被正面金屬化柵格遮擋的區域 而導致的損失。例如在申請案WO_A_98/54763和申請案 EP-A-2.068.369 中描述了 MWT 技術。 在MWT技術構架中，熟知的是，在典型的mwt形成工 藝中’印刷方法始於在面向上的背面B上操作，而正面f面 向下並與支撐件接觸。圖2A和圖2B圖示了在典型mwt印 刷方法期間的基板250A和250B’該方法一般包括三個印刷 步驟。在第-印刷步驟中，第—基板25从被定位成使得正 面F面對支撐件218。在第一印刷步驟期間，藉由向孔内部 201234622 施加膠而使孔金屬化，該膠具有導電功能和接觸功能任—種 或兩種，該等孔穿過第一基板25〇 A設置在正面F和背面B 之間。此外，在第一印刷步驟期間也使用相同的膠來印刷匯 流條"將匯流條印刷成使得該等匯流條與孔電接觸。按所需 的匯流條圖案（該匯流條包括孔的開口）印刷金屬膠M，並 且借助於通過支撐件218的真空吸力將膠吸引到孔中。但 是，因金屬膠Μ的流體特性，導致用以將金屬膠M吸引到 孔中而施加的真空吸力通常會造成金屬膠厘在支撐件218表 面上的不想要的沉積物D。 在第一印刷步驟之後，翻轉第一基板25〇A (例如18〇 度），使得背面B定位在支撐件218上。在第二印刷步驟期 間，在正面F面向上的情況下，在第一基板25〇A的正面f 上印刷指狀物。在第二步驟之後，再次翻轉第一基板25〇a， 使得正面F面對支撐件218，並使用含鋁膠而使第一基板 250A的背面金屬化。隨後，如圖2B中所示然後將第二基 板250B引入到印刷站中，也是背面b面向上，並且與第一 基板250A類似地處理第二基板。 該一步法可稱為「背面_正面-背面」方法（參考分別進 打絲網印刷的表面），該三步法的一缺點在於，用於使孔金 屬化的導電膠通常會導致支撐件218受污染。該污染歸因於 重力作用和吸力作用，該吸力用於在金屬化期間將金屬膠Μ 吸引到孔中。重力和過吸力通常會造成膠不合需要地通過孔 遷移（travel)並污染支撐件218。該污染形成了不想要的沉 201234622 積物D，當將第二基板150傳遞到支樓件218上時，該等沉 積物D會污染隨後處理的第二基板150的正面p·。該污染會 導致指狀物的印刷品質較差，且因此該污染降低了最終製造 器件的轉換效率。「背面-正面-背面」印刷方法的另一缺點在 於在第一印刷步驟期間必須使用相同膠既填充孔又製作匯 流條。 因此’需要用於印刷基板的具有減少的污染和改良的印 刷品質的技術。 本申請人已經設計、測試並具體化了本發明，以克服現 有技術缺陷並獲得該等以及其他的目的和優勢。 【發明内容】 本發明的實施例大體係關於印刷MWT太陽能電池的方 法。該方法包括以下步驟：將太陽能電池基板的非光接收側 定位在支撐件上。太陽能電池基板具有複數個孔，該複數個 孔穿過該太陽能電池基板形成。之後使該複數個孔金屬化。 使孔金屬化之步驟包括以下步驟：將第一含銀導電膠施加至 孔内，或者將第一含銀導電膠沉積在孔的内表面上。第一含 銀導電膠與基板的正面和背面電連通。之後，使用第二含銀 膠將複數個集電指狀物形成在基板的正面上。複數個集電指 狀物電耦合到複數個金屬化孔中的至少一個，並且複數個集 電扣狀物自複數個金屬化孔中的至少一個基本徑向延伸。然 201234622 後可翻轉基板，並且可在基板的背面上執行一或多個印刷工 藝* 〇 在一個實施例中，印刷基板的方法包括以下步驟：將基 板疋位在印刷單元内的支撐件上。該基板具有與支撐件接觸 的煮面、與背面相對的正面，和在正面和背面之間延伸的複 數個孔。然後，藉由從基板正面的方向施加第一含銀膠使孔 金屬化，該等孔在基板正面和基板背面之間延伸。使孔金屬 化之步驟包括以下步驟：用第一含銀膠填充孔，或者將第一 含銀膠沉積在孔的内表面上’以形成基板正面和基板背面之 間的電連接。接著’藉由在基板正面上印刷第二含銀膠而在 基板正面上形成複數個指狀物。該複數個指狀物與至少一個 孔電連通’並且該複數個指狀物自至少一個孔徑向延伸。然 後’翻轉基板，並將包括銀和鋁的第三膠印刷到基板背面 上，以使複數個匯流條金屬化，該複數個匯流條與該等孔電 連通。在該等孔的金屬化和該複數個指狀物形成後，印刷該 等匯流條。然後’將包括鋁的第四朦印刷到基板背面上，以 使基板的背面金屬化。 在另一實施例中，在使孔金屬化的印刷操作之前按時間 順序至少部分地執行形成指狀物的印刷操作。 在再一實施例中，在使孔金屬化的印刷操作之後按時間 順序執行形成指狀物的印刷操作。 在又一實施例中，將形成指狀物的印刷操作分成至少兩 201234622 個子操作。第一子操作包括使用第二含銀接觸膠印刷第—層 指狀物，隨後的第二子操作包括使用第一含銀膠在第二含銀 膠上印刷第二層指狀物。 在又一實施例中，在使孔金屬化的印刷操作之前按時間 順序執行第一子操作。在時間和空間上與使孔金屬化的印刷 操作同時執行第二子操作，其中使用相同的第一含銀膠形成 指狀物和使孔金屬化。 在又一實施例中’該方法包括以下步驟：使用雷射劃線 技術將正面金屬化與背面金屬化隔離。 在又一實施例中’用於印刷基板的方法包括以下步驟： 將基板定位在支撐件上。該基板具有與支撐件接觸的背面和 與背面相對的正面。接著，藉由在基板正面上印刷第一含銀 膠而在基板正面上形成複數個指狀物。然後，翻轉基板，使 得基板正面與基板支撐件接觸，並且將含銀和鋁的第二膠印 刷到基板背面上以使複數個匯流條金屬化。 【實施方式】 本發明的實施例大體係關於印刷MWT太陽能電池的方 法。該方法包括以下步驟：將太陽能電池基板的非光接收側 定位在支撐件上。該太陽能電池基板具有複數個孔，該複數 個孔穿過該太陽能電池基板形成。接著，使該複數個孔金屬 201234622 化使該等孔金屬化之步驟包括以下步驟：將第一含銀導電 膠鉍加到孔内，或者將第一含銀導電膠沉積在孔的内表面 上。該第一含銀導電膠與基板的正面和背面電連通。接著， 使用第二含銀膠將複數個集電指狀物形成在基板的正面 上。複數個集電指狀物電耦合到複數個金屬化孔中的至少一 並且複數個集電指狀物自複數個金屬化孔中的至少一個 基本徑向延伸。然後，可翻轉基板，並可在基板背面上執行 一或多個印刷工藝。 如本文中所使用的，術語「正面」指在工藝終點時基板 表面上設置有指狀物的彼基板表面（例如太陽能電池的光接 收表面），而術語「背面」是與正面相對的表面。 除非另外限定’否則此處和下文所使用的全部技術術語 和科技術語都具有與本發明所屬技術領域的普通技術人員 通常理解相同的含義。在有衝突的情況下，包括定義，本申 °月優先。本文使用術語「包括」以及該術語的變型，諸如「具 有」和「包含」，來表示包括清楚表達的整體，或者清楚表 達的多個整體，但是不包括任意其他整體或者多個任意其他 整體’除非在上下文或者使用中需要排他性的解釋該術語。 參考按順序進行絲網印刷的表面，本發明可限定為「正 面-正面-背面-背面」，由於減少了所需的基板翻轉步驟數 目’因此與三步印刷的傳統方式相比，本發明是一項改良。 本發明的一些實施例提供了四個印刷操作，該四個印刷操作 11 201234622 始於基板正面。而且，在本發明的一些實施例中，使用專用 印刷膠用於在所執行的不同印刷步驟中金屬化。如此做便於 根據待金屬化的部件調配（tailoring )專用印刷膠’該部件 例如通孔、指狀物、匯流條或者背面金屬化（metallization)。 圖3圖示了根據本發明實施例形成的太陽能電池C。圖 3中圖示的太陽能電池C包括被構造為薄線或指狀物316的 上部接觸結構，該等薄線或指狀物在太陽能電池C的光接收 側上徑向延伸。每一群組線或指狀物316都從一或多個孔向 各方向伸展出（radiate)，該孔穿過太陽能電池設置。線或指 狀物3 16收集經由光伏效應產生的電流，並且線或指狀物316 通過該孔將電流供應給匯流條414 (圖4中所示），該等匯流 條414提供在基板350背面上，與背面金屬化417相鄰。 圖4圖示了根據本發明的實施例形成在基板35〇上的太 陽能電池的截面圖。基板350包括p型基區421、η型發射 區422和ρ-η結區423，該ρ-η結區423設置在ρ型基區421 和η型發射區422之間。藉由用η型摻雜劑（例如磷（ρ )、 砷（As)或者銻（Sb))摻雜基板150來形成11型發射區422, 以增加該η型發射區中存在的負電荷（亦即電子）數量。類 似地，藉由在摻雜工藝期間將三價原子添加到晶格中來形成 ρ型基區421。將三價原子添加到晶格中導致晶格的四個正 常共價鍵中的一個共價鍵的電子丟失。以此方式摻雜原子 能夠從附近原子的共價鍵接受電子，以補償第四個鍵。接受 電子導致附近原子損失了半鍵，產生「空穴」。 12 201234622 當光照爿太陽能電池c _，伴隨著％子照射，光子能量 在P-η結區423兩侧上產生電子空穴對。電子經由pn結擴 ㈣較低能級’而空穴以相反方向擴散，在發射極產生負電 荷並在基極產生相應的正電荷。當在發射極和基極之間形 成電路，並將P_n結暴露給—定光波長時，將有電流流動。 經由半導體產生的電流流過指㈣316，纟直至太陽能電池 c的背面，該等指狀物316設置在太陽能電池c的正面（亦 即’光接收表面）上，該正面用F表示，該背面用b表示。 太陽能電池Cit常用諸如氮化；^的介電材❹層覆蓋，以用 作抗反射塗層（ARC )，以便使自太陽能電池c正面F的光 反射的情況最小化。 才曰狀物316與基板350電接觸，並且指狀物316能夠達 成與基板350的一或多個摻雜區域（例如n型發射區422) 的歐姆連接。歐姆接觸是在半導體器件上已經被預先設置的 區域’使得器件的電流電壓曲線（I_V)是線性和對稱的；亦 即，在摻雜的矽區與金屬接觸之間不存在高電阻介面。太陽 能電池性能和在太陽能電池生產工藝中制得的電路可靠性 需要低電阻和穩定接觸❶為了增強與太陽能電池器件的接 觸’通常將指狀物316定位在高摻雜區上，以便允許形成歐 姆接觸，該高摻雜區形成於基板表面h由於高摻雜區的電 特性，以致尚摻雜區往往會阻擋可穿過該等高摻雜區的光 量，或者使可穿過該等高摻雜區的光量最小化，因此希望使 該高摻雜區相對較小，以便使被阻擋的光量最小化。但是， 13 201234622 同時，該等高摻雜區又必須足夠大’以確保指狀物3丨6能夠 可靠地形成在該等區上。可使用各種圖案化技術，例如藉由 根據圖案使用擴散阻擋層來擴散磷，在基板表面上制得高摻 雜區’以產生具有較高摻雜的區域和較低摻雜的區域。藉由 形成與基板350的p型基區的歐姆接觸，背部接觸完成了產 生電流所需的電路，該背部接觸諸如形成在基板35〇背面B 上的背面金屬化417。 圖5圖示了根據本發明一個實施例在印刷工藝期間的基 板3 50。在操作560中，將基板350定位在支撐件的處理平 面P上，該支撐件諸如處理組769 (見圖7中所示），該基板 350諸如具有自正面F延伸至背面B的通孔551的矽基晶 片。基板350被定位成使得基板15〇的正面F面向印刷站的 印刷裝置，該印刷站包括複數個印刷單元，該印刷裝置諸如 絲網印刷裝置。處理平s p %常具有紙或者其他蒸騰 (transpirant)材料（例如多孔材料以使氣體能通過該多孔 材料机動）的基本成分，以便真空吸附基板35〇。真空吸力 將基板150保持在處理平面P上的所需位置，由此改良印刷 品質和精度。 在操作561 +，將含銀導電# 553印刷在基板35〇正面 F上’以使集電指狀物5】6s 切的第一層金屬化。在操作562和201234622 VI. Description of the Invention: TECHNICAL FIELD OF THE INVENTION Embodiments of the Invention A large system relates to a method of printing a substrate used in the manufacture of a solar cell, such as a germanium substrate. [Prior Art] A solar cell is a photovoltaic device that directly converts sunlight into electrical energy. The market has grown rapidly in the last decade with an annual growth rate of more than 30%. Some articles have assumed that the world's energy production from solar cells will exceed 10 GWp in the near future. It has been estimated that more than 95% of all solar modules are based on Shishi substrates. The high growth rate of the market, combined with this demand to substantially reduce the cost of solar power, has led to many challenges in producing commercially viable high quality solar cells. Some of the challenges that affect the commercial viability of solar cells include manufacturing costs, solar cell performance, and manufacturing capabilities. Solar cells typically have one or more P_n junctions. Each p n junction includes two different regions inside the semiconductor material, one of the two different regions being a P-type region and the other side being an n-type region. When the pn junction of the solar cell is exposed to sunlight (consisting of photon-derived energy), it is converted into electricity by means of photovoltaic effect solar light. The solar cell produces a specific amount of electrical energy, and the solar energy = pool is concentrated in a module of a certain size in order to transmit the required amount of system energy. The solar module is attached to the panel using a specific frame and connector. Tai 4 201234622 The solar cells are usually formed of a tantalum substrate, which may be a single crystal germanium substrate or a germanium substrate. A typical solar cell includes a hard substrate such as a wafer, the thickness of which is typically less than about 〇·3 mn^ 矽. The substrate typically has a thin layer of n-type germanium, the n-type thin layer being above the p-type region, the p-type A region is formed on the substrate. Fig. 1 schematically illustrates a standard tantalum solar cell C» thin line or finger 116 formed of a substrate i 5 设置 disposed on the front side (i.e., the light receiving surface) of the substrate 150. The thin wires or fingers 116 are parallel to each other, and the thin wires or fingers 116 are used to collect the current generated by the photovoltaic effect and supply the current to a collector bar or a contact bus bar (c〇ntact busbar) , such as bus bar 114. The bus bar 114 is also disposed on the light receiving surface of the solar cell c, and the bus bar 114 is disposed perpendicular to the fingers 116 and in electrical contact with the fingers 116. The design has been printed on an object such as a fabric or ceramic using screen printing, and screen printing is used in the electronics industry to print a model of the electronic component on the surface of the substrate, such as electrical or electrical interconnections. The method of manufacturing a solar cell in the state of the art also uses a screen printing method. It is well known that electrical circuits and electrical contacts of solar cells are typically fabricated by means of a screen printing process using suitable conductive or contact adhesives, which are typically fingers and bus bars. Screen printing is performed in one or more screen printing stations. Each battery is moved into and out of the screen printing station while it is being carried on the conveyor. The conveyor has a surface or processing plane on which the solar cells to be treated are positioned during the printing process. 5 201234622 Usually, solar cells can be divided into different types according to the structure of solar cells, one type is called "back contact" solar cells. The back contact solar cell is a solar cell that is placed on the back of the solar cell (i.e., the non-light receiving surface) for the ohmic contact of the opposite doped region of the solar cell. The presence of contact on the back side of the solar cell reduces the loss of illumination which would otherwise result from the presence of metal contact on the light receiving surface of the solar cell. A method of fabricating a back contact solar cell includes a Metal Wrap Through (MWT) technique that positions two external contacts (or bus bars) 114 for opposite doped regions on the back side b, Position the collector (or finger) on the front side. The current collected on the front side F via the collector or fingers is conducted to the back surface B through the holes extending across the substrate. Thus, current is collected via one or more bus bars positioned on the back side of the solar cell. In this way, because the bus bars are positioned on the non-illuminated surface of the solar cell, losses due to areas that are obscured by the front metallization grid are reduced. The MWT technique is described, for example, in the application WO_A_98/54763 and the application EP-A-2.068.369. In the MWT technology architecture, it is well known that in a typical mwt forming process, the printing process begins with operation on the upwardly facing back side B with the front side facing down and in contact with the support. 2A and 2B illustrate substrates 250A and 250B' during a typical mwt printing method. The method generally includes three printing steps. In the first printing step, the first substrate 25 is positioned such that the front surface F faces the support member 218. During the first printing step, the holes are metallized by applying glue to the interior of the hole 201234622, the glue having either or both of a conductive function and a contact function, the holes being disposed on the front side through the first substrate 25A Between F and back B. In addition, the same glue is used to print the bus bars during the first printing step. The bus bars are printed such that the bus bars are in electrical contact with the holes. The metal glue M is printed in the desired bus bar pattern (the bus bar includes the opening of the hole), and the glue is attracted into the hole by vacuum suction through the support member 218. However, due to the fluid nature of the metal capsule, the vacuum suction applied to attract the metal glue M into the hole typically causes unwanted deposits D of the metal glue on the surface of the support member 218. After the first printing step, the first substrate 25A (e.g., 18 degrees) is flipped such that the back side B is positioned on the support member 218. During the second printing step, with the front side F facing up, the fingers are printed on the front side f of the first substrate 25A. After the second step, the first substrate 25A is again flipped so that the front surface F faces the support member 218, and the back surface of the first substrate 250A is metallized using the aluminum-containing glue. Subsequently, the second substrate 250B is then introduced into the printing station as shown in Fig. 2B, also with the back surface b facing upward, and the second substrate is processed similarly to the first substrate 250A. This one-step method may be referred to as a "back_front-back" method (refer to the screen-printed surface, respectively). A disadvantage of the three-step method is that the conductive paste used to metallize the holes typically results in the support member 218. Infected. This contamination is attributed to gravity and suction forces that are used to attract the metal capsules into the pores during metallization. Gravity and oversuction typically cause the glue to undesirably travel through the aperture and contaminate the support 218. This contamination forms an unwanted sinking 201234622. When the second substrate 150 is transferred to the branch member 218, the deposits D can contaminate the front side p of the subsequently processed second substrate 150. This contamination can result in poor print quality of the fingers, and thus the contamination reduces the conversion efficiency of the final fabricated device. Another disadvantage of the "back-front-back" printing method is that the same glue must be used to fill both the holes and the bus bars during the first printing step. Therefore, there is a need for a technique for printing a substrate with reduced contamination and improved printing quality. The Applicant has devised, tested and embodied the present invention in order to overcome the <RTIgt; SUMMARY OF THE INVENTION Embodiments of the present invention are directed to methods of printing MWT solar cells. The method includes the steps of positioning a non-light receiving side of a solar cell substrate on a support. The solar cell substrate has a plurality of holes formed through the solar cell substrate. The plurality of holes are then metallized. The step of metallizing the holes includes the steps of applying a first silver-containing conductive paste into the holes or depositing a first silver-containing conductive paste on the inner surface of the holes. The first silver-containing conductive paste is in electrical communication with the front and back sides of the substrate. Thereafter, a plurality of collector fingers are formed on the front side of the substrate using the second silver-containing glue. A plurality of current collecting fingers are electrically coupled to at least one of the plurality of metallized holes, and the plurality of current collecting buttons extend substantially radially from at least one of the plurality of metallized holes. While 201234622, the substrate can be flipped and one or more printing processes can be performed on the back side of the substrate. 〇 In one embodiment, the method of printing a substrate includes the steps of: clamping the substrate onto a support within the printing unit. The substrate has a cooking surface in contact with the support, a front side opposite the back side, and a plurality of holes extending between the front side and the back side. The holes are then metallized by applying a first silver-containing glue from the direction of the front side of the substrate, the holes extending between the front side of the substrate and the back side of the substrate. The step of metallizing the holes includes the steps of: filling the holes with the first silver-containing glue, or depositing the first silver-containing glue on the inner surface of the holes to form an electrical connection between the front side of the substrate and the back side of the substrate. Then, a plurality of fingers are formed on the front surface of the substrate by printing a second silver-containing paste on the front surface of the substrate. The plurality of fingers are in electrical communication with the at least one aperture and the plurality of fingers extend radially from the at least one aperture. The substrate is then flipped over and a third paste comprising silver and aluminum is printed onto the back side of the substrate to metallize the plurality of bus bars, the plurality of bus bars being in electrical communication with the holes. After the metallization of the holes and the formation of the plurality of fingers, the bus bars are printed. The fourth crucible comprising aluminum is then printed onto the back side of the substrate to metallize the back side of the substrate. In another embodiment, the printing operation to form the fingers is performed at least partially in chronological order prior to the printing operation to metallize the holes. In still another embodiment, the printing operation to form the fingers is performed in chronological order after the printing operation to metallize the holes. In yet another embodiment, the printing operation to form the fingers is divided into at least two 201234622 sub-operations. The first sub-operation includes printing the first layer of fingers using the second silver-containing contact paste, and the subsequent second sub-operation includes printing the second layer of fingers on the second silver-containing glue using the first silver-containing glue. In yet another embodiment, the first sub-operation is performed in chronological order prior to the printing operation to metallize the holes. A second sub-operation is performed simultaneously with the printing operation to metallize the holes in time and space, wherein the same first silver-containing glue is used to form the fingers and metallize the holes. In yet another embodiment, the method includes the step of isolating the front side metallization from the back side metallization using a laser scribing technique. In yet another embodiment, the method for printing a substrate includes the steps of: positioning a substrate on a support. The substrate has a back surface in contact with the support and a front surface opposite the back. Next, a plurality of fingers are formed on the front surface of the substrate by printing a first silver-containing paste on the front surface of the substrate. Then, the substrate is flipped so that the front side of the substrate is in contact with the substrate support, and a second offset containing silver and aluminum is applied to the back surface of the substrate to metallize the plurality of bus bars. [Embodiment] An embodiment of the present invention relates to a method of printing an MWT solar cell. The method includes the steps of positioning a non-light receiving side of a solar cell substrate on a support. The solar cell substrate has a plurality of holes formed through the solar cell substrate. Then, the step of refining the plurality of holes metal 201234622 to metallize the holes includes the steps of: adding the first silver-containing conductive adhesive to the holes, or depositing the first silver-containing conductive paste on the inner surface of the holes. . The first silver-containing conductive paste is in electrical communication with the front and back sides of the substrate. Next, a plurality of collector fingers are formed on the front side of the substrate using a second silver-containing glue. A plurality of collector fingers are electrically coupled to at least one of the plurality of metallization holes and the plurality of collector fingers extend substantially radially from at least one of the plurality of metallization holes. The substrate can then be flipped and one or more printing processes can be performed on the back side of the substrate. As used herein, the term "front side" refers to the surface of a substrate on which the fingers are disposed on the surface of the substrate (e.g., the light-receiving surface of the solar cell), and the term "back surface" is the surface opposite the front side. All technical and scientific terms used herein and hereinafter have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, including definitions, this application is preferred. The term "comprising" and variations of the term, such as "having" and "comprising", are used to mean a whole that includes a clear expression, or a plurality of integers that are clearly expressed, but does not include any other whole or a plurality of any other whole. Unless the context or use requires an exclusive explanation of the term. Referring to the screen-printed surface in sequence, the present invention can be defined as "front-front-back-back", since the number of required substrate flipping steps is reduced', thus the present invention is compared to the conventional manner of three-step printing. An improvement. Some embodiments of the present invention provide four printing operations that begin at the front side of the substrate. Moreover, in some embodiments of the invention, a proprietary printing paste is used for metallization in the different printing steps performed. This facilitates tailoring the special printing adhesive depending on the part to be metallized, such as through holes, fingers, bus bars or metallization. FIG. 3 illustrates a solar cell C formed in accordance with an embodiment of the present invention. The solar cell C illustrated in Fig. 3 includes an upper contact structure configured as a thin line or finger 316 that extends radially on the light receiving side of the solar cell C. Each group of wires or fingers 316 is radiated from one or more apertures in various directions, the apertures being disposed through the solar cell. Lines or fingers 3 16 collect current generated by the photovoltaic effect, and wires or fingers 316 supply current through the holes to bus bars 414 (shown in Figure 4), which are provided on the back of substrate 350 Upper, adjacent to the back metallization 417. Figure 4 illustrates a cross-sectional view of a solar cell formed on a substrate 35A in accordance with an embodiment of the present invention. The substrate 350 includes a p-type base region 421, an n-type emitter region 422, and a p-n junction region 423 disposed between the p-type base region 421 and the n-type emitter region 422. The 11-type emitter region 422 is formed by doping the substrate 150 with an n-type dopant such as phosphorus (ρ), arsenic (As) or antimony (Sb) to increase the negative charge present in the n-type emitter region ( That is, the number of electronic). Similarly, the p-type base region 421 is formed by adding a trivalent atom to the crystal lattice during the doping process. The addition of a trivalent atom to the crystal lattice results in the loss of electrons in one of the four normal covalent bonds of the crystal lattice. Doping atoms in this way is capable of accepting electrons from covalent bonds of nearby atoms to compensate for the fourth bond. Accepting electrons causes a nearby atom to lose a half bond, creating a "hole." 12 201234622 When the solar cell c _ is illuminated, with the % sub-irradiation, the photon energy generates electron-hole pairs on both sides of the P-η junction region 423. The electrons expand through the pn junction (4) the lower energy level' and the holes diffuse in the opposite direction, producing a negative charge at the emitter and a corresponding positive charge at the base. When a circuit is formed between the emitter and the base and the P_n junction is exposed to a constant wavelength, current will flow. The current generated by the semiconductor flows through the finger (four) 316, up to the back side of the solar cell c, which is disposed on the front side (ie, the 'light receiving surface) of the solar cell c, the front side being denoted by F, the back side being used b indicates. The solar cell Cit is usually covered with a dielectric layer such as nitriding to serve as an anti-reflective coating (ARC) to minimize the reflection of light from the front surface F of the solar cell c. The ribs 316 are in electrical contact with the substrate 350 and the fingers 316 are capable of reaching an ohmic connection with one or more doped regions of the substrate 350 (e.g., n-type emitter regions 422). The ohmic contact is a region that has been previously set on the semiconductor device such that the current-voltage curve (I_V) of the device is linear and symmetrical; that is, there is no high-resistance interface between the doped germanium region and the metal contact. Solar cell performance and circuit reliability produced in solar cell production processes require low resistance and stable contact ❶ in order to enhance contact with the solar cell device 'typically the fingers 316 are positioned on highly doped regions to allow ohmic formation Contact, the highly doped region is formed on the surface h of the substrate due to the electrical characteristics of the highly doped region, so that the doped region tends to block the amount of light that can pass through the highly doped regions, or can pass through the high doping The amount of light in the miscellaneous region is minimized, so it is desirable to make the highly doped region relatively small in order to minimize the amount of blocked light. However, 13 201234622 at the same time, the highly doped regions must again be large enough to ensure that the fingers 3丨6 can be reliably formed on the regions. Various patterning techniques can be used, such as by diffusing phosphorus using a diffusion barrier according to the pattern, producing a highly doped region on the surface of the substrate to produce regions with higher doping and regions of lower doping. By forming an ohmic contact with the p-type base region of the substrate 350, the back contact completes the circuitry required to generate an electrical current, such as the backside metallization 417 formed on the backside B of the substrate 35. Figure 5 illustrates a substrate 350 during a printing process in accordance with one embodiment of the present invention. In operation 560, the substrate 350 is positioned on a processing plane P of a support, such as a processing set 769 (shown in Figure 7), such as a via 551 having a front surface F extending to the back side B. Silicon based wafer. The substrate 350 is positioned such that the front side F of the substrate 15 turns facing the printing station of the printing station, the printing station comprising a plurality of printing units, such as screen printing units. The treatment flat s p % often has the basic composition of paper or other transpirant material (e.g., a porous material to allow gas to be maneuvered through the porous material) to vacuum adsorb the substrate 35 〇. The vacuum suction maintains the substrate 150 at a desired position on the processing plane P, thereby improving print quality and precision. At operation 561 +, the silver-containing conductive # 553 is printed on the front side F of the substrate 35 to metallize the first layer of the current collecting fingers 5 6s. At operation 562 and
563中’使用含銀導雷朦| a P 膠552來使孔金屬化（操作563 )及 在集電指狀物5 1 6上印篇丨丨银 a , 工I3刷第二層（操作562)。因而，集電指 狀物5 1 6是使用兩個子極 刼作而形成的，每一個子操作形成集 201234622 電指狀物516的不同層。雙層集電指狀物516的優勢在於在 集電指狀物516上的第二次印刷增加了集電指狀物516高度 和寬度之間的比例（亦即縱橫比）。能夠印刷具有減少的寬 度的雙層集電指狀物516,同時由於指狀物5 16增加的高度 仍能提供足夠的電流傳輸路徑（例如足夠低的電阻率）。藉 由形成具有減小的寬度的集電指狀物516，由此減小了光接 收表面被集電指狀物516阻擋的表面積。 本發明利用兩種不同的膠（例如含銀導電膠552和含銀 導電膠553 )用於印刷在基板的正面上，因而允許每種含銀 膠5 52、5 53的成分適合於特定應用。例如，可選擇具有適 當粘度的膠（即含銀膠552 )用於孔551的金屬化，以便填 充通孔或者將膠沉積在通孔的内表面上而避免使用吸力。藉 由避免使用吸力，簡化了印刷工藝且減小了污染支撐件表面 的可能性。相反，含銀膠553的粘度可大於含銀膠552的粘 度以防止當含銀膠553印刷到基板350正面F上時含銀膠 553「流動」。而且，根據所需的電導率值，不管用於匯流條 414的膠如何（操作564中圖示），同樣可選擇含銀膠552用 於孔551，而可選擇用於匯流條的膠作為接觸膠。特別是， 用於製ia .匯流條的基於銀和鋁的理想接觸膠，例如使與承載 電流的帶狀電線或者導線接觸變得容易。 此外，儘管圖示操作562和563同時發生，但是應知可 P刷第—層集電指狀物516之前使該等孔551金屬化，或 者反之亦然。 ~ 15 201234622 在操作562和563之後，且在操作564之前，例如使用 機械手翻轉基板350,並且將該基板定位在第二印刷單元的 第二處理平面P上，使得正面F放置在第二處理平面p上。 在基板350的背面B面對印刷裝置的情況下，使用第三導電 膠554將匯流條414印刷在背面B上，該背面B與金屬化孔 551電接觸，該第三導電膠包含銀和鋁。 在操作565中，在背面B仍面對印刷裝置的情況下，使 用第四含鋁膠555在不被匯流條414覆蓋的區域内使背面B 金屬化，以形成背側金屬化471 ^由此，除了在背面金屬化 417和匯流條414之間的小間隙或間隔外，基板3 5 〇的基本 整個背面B都被背面金屬化417和匯流條414覆蓋，該等小 間隙或間隔便於背面金屬化417和匯流條414的電隔離。在 一些實施例中，該方法還提供了處理操作566，借助於該處 理操作566使用雷射在（匯流條414)和在基板35〇背面上 的背面金屬化417之間劃線絕緣元件5S6，以在背面金屬化 和匯流條4 14之間形成電隔離。 圖6是根據本發明另一實施例在印刷工藝期間的基板的 不意性圖示。在操作670中，將基板35〇定位在印刷單元的 處理平面P上，該基板350諸如單晶矽基板，該單晶矽基板 具有從正面F延伸至背面b的孔551。在操作671中從基 板350正面F的方向印刷含銀導電膠5S2，以使孔5Μ金屬 化。可藉由用含銀導電膠552填充孔551，或者藉由將含銀 導電膠552塗覆到孔551的内表面並留下貫穿該等孔551的 16 201234622 開口，而使該等孔551金屬化。在操作672中，將含銀導電 膠553印刷在基板350正面F上，以形成金屬化的集電指狀 物616。該等金屬化的集電指狀物616與金屬化的通孔551 電接觸且自該金屬化的通孔向551各方向伸展出。儘管圖示 了操作671在操作672之前發生，但是應知操作672可在操 作671之後發生。此外，與圖5的操作561、562和563相 反，圖6的金屬化集電指狀物616僅含有使用單種膠印刷的 單個金屬層，而不是如參看圖5所描述的多層集電指狀物 516 〇 回到圖6，在操作672之後且在操作673之前，在第二 印刷單元的第二處理平面P上翻轉基板35〇正面向下。在基 板350的背面B面對印刷裝置的情況下，使用第三導電膠554 將匯流條414印刷在背面b上，該背面B與金屬化的孔551 電接觸’該第三導電膠554包括銀和鋁。 在操作674中，在背面B仍面對印刷裝置的情況下使 用第四含鋁膠555在未被匯流條414覆蓋的區域中使背面B 金屬化，以形成背面金屬化417。因而，背面金屬化417和 匯流條414覆蓋了基板350的基本整個背面b。但是，在背 面金屬化417和匯流條414之間留有小間隙以保持背面金屬 化417和匯流條414之間的電隔離。在一些實施例中，該方 法包括操作675，在操作675中，在匯流條414和在基板35〇 背面上的背面金屬化417之間劃線諸如溝槽之類的絕緣元件 556 ’以將背面金屬化與匯流條414電隔離。 17 201234622 參看圖5和圖6,在操作562、563 (圖5)和操作⑺ (圖〇之後’-些實施例中，將基板35〇定位在第二處理 平面上同時將該基板翻轉，以便將第二基板350提供在最初 處理平面P上1二基板35G的f φΒ敎位在最初處理平 面Ρ上，由此使工藝迴圈能更快地進行。 圖7疋基板處理系統7GG的示意性等角視圖在基板處 理系統700中可根據本發明的方法處理基板。㈣統7〇〇包 括兩個輸人傳送機767、致動器組件768、複數個處理組769、 複數個處理頭776、兩個輸出傳送機777,和系統控制器778。 輸入傳送機767被配置成平行處理構造，使得每一個輸入傳 送機都能從諸如輸人傳送機779之類的輸人裝置接收未處理 的基板350’並且每一個輸入傳送機將每個未處理的基板 傳送至處理組769,該處理組耦合到致動器組件768。此外， 輸出傳送機777被配置為平行的，使得每—個輸出傳送機都 能自處理組769接收已處理的基板35〇，並且每一個輸出傳 送機將每個已處理的基板350傳送至諸如排出傳送機78〇之 類的基板去除裝置。每個排出傳送機78〇都適配於將已處理 的基板350傳送通過烘爐781，以經由處理頭776固化沉積 在基板350上的材料。 系統700也可包括檢查系統782，檢查系統782適配於 在處理之前和之後定位和檢查基板350。檢查系統782包括 一或多個照相機783，一或多個照相機783定位成檢查基板 350’該基板350定位在裝載位置/卸載位置「1」和「3」中， 18 201234622 如圖7和8中所示。檢查系統782通常包括至少一個照相機 783 (例如CCD照相機）和其他電子部件，該等電子部件能 夠定位、檢查並將結果傳輸至系統控制器778。在—個實例 中，檢查系統782適配於定位輸入基板35〇的某些特徵的位 置’並將檢查結果傳輸至系統控制器778，以便分析基板35〇 的取向和位置。於是，系統控制器778能確定在處理基板35〇 之前將基板350定位在處理頭776下方。在另一實例中，檢 查系統782檢查基板35〇，以便能夠從生產線去除受損的基 板3 50。此外，應知處理組769每一個都可含有燈，或者其 他類似的光學幅射裝置，以照亮定位於該處理組上的基板 3 50 ’使得基板35〇能夠更容易地被檢查系統782檢查。 系統700是絲網印刷處理系統，並且處理頭776包括絲 網印刷部件，該等絲網印刷部件配置成將材料（諸如導電膠） 的圖案化層絲網印刷在基板3 5 〇上。在絲網印刷的情況下， 處理頭776用於在基板35〇的正面F和背面B上印刷不同的 膠’該等膠包括膠552、553、554和555 (如圖5中所示）。 或者應知預期系統7 0 0可以是喷墨印刷系統，並且處理頭 776包括喷墨印刷部件，該等喷墨印刷部件配置成將材料的 圖案化層沉積在基板350上。 圖8疋圖7中描述的系統700的示意性平面圖。圖8圖 示了具有兩個處理組769 (在位置「L和「3」中）的該系 統700，每—個處理組769都被定位成將已處理的基板350 傳送至輸出傳送機777和自輸入傳送機767接收未處理的基 19 201234622 板3 50。由此’在系統7〇〇中，基板移動通常沿著如圖7和 圖8中圖示的路徑「A」。在該構造中，其他兩個處理組 中的每一個（在位置「2」和「4」中）都被定位在處理頭776 下方，使得能在位於各自處理組769上的未處理基板35〇上 執行處理（例如絲網印刷或者喷墨印刷）。系統7〇〇的平行 處理構造允許在處理系統占地面積最小化的情況下具有增 加的處理能力。儘管將系統700描述為具有兩個處理頭776 和四個處理組769,但是應知系統700可包括其他處理頭776 和/或處理組769，而不偏離本發明的範圍。 在該系統700中利用的兩個頭776是可從意大利的應用 材料（Applied Materials，Italia)S.r丄市售購買的傳統絲網印 刷頭，該等傳統絲網印刷頭適配於在絲網印刷工藝期間以所 需圖案將材料沉積在基板350表面上，該基板設置在位置「2」 或者「4」處的處理組769上。但是應知也可使用其他組或 者其他支撐件來實踐本文描述的本發明的實施例。處理頭 776包括複數個致動器785 (例如步進式電動機或者伺服電 動機）’該複數個致動器與系統控制器778連通。致動器785 可用於調整絲網印刷掩模（未圖示）關於基板35〇的位置和 /或角度取向，該基板設置在處理頭776内。絲網印刷掩模一 般是金屬片或者金屬板’該金屬片或金屬板具有複數個孔、 槽或者其他孔隙’以在基板350表面上限^絲網印刷材料的 圖案和位置’該等其他孔隙貫穿該金屬片或金屬板形成。 絲網印刷材料可包括導電墨或導電膠，介電墨或介電 20 201234622 膠、摻雜劑凝膠、蝕刻凝膠、一或多種掩模材料或者其他導 電材料或介電材料。一般地，藉由使用致動器785和資訊來 定向絲網印刷掩模，使待沉積到基板350的表面上的絲網印 刷圖案以自動方式與基板350對準，該資訊由系統控制器778 自檢查系統782接收。在一個實施例中，處理頭776適配於 在太陽能電池基板上沉積含金屬或者含電介質的材料，該太 陽能電池基板的寬度在約125 mm和約156mm之間，並且長 度在約70 mm和約156 mm之間。 輸入傳送機767和輸出傳送機777包括兩個傳送帶 786，以藉由使用致動器來支撐基板35〇並將基板35〇傳送 至系統700内的所需位置’該致動器與系統控制器778連 通。雖然圖7和圖8大體圖示了具有兩個傳送帶786的基板 傳送系統，但是可使用其他類型的傳送機構，用於執行相同 的基板傳送功能和定位功能，而不會改變本發明的基本範 圍。此外，應知輸入傳送機767和輸出傳送機每一個都可具 有一個傳送帶，或者可具有多於兩個傳送帶。 系統控制器778促進整個系統700的控制和自動化，並 且系統控制器778可包括中央處理單元（CPU)、記憶體和支 援電路（或者I/O )。CPU可以是任意形式電腦處理器中的一 種，該t腦處理器用在工業設置中，用於控制各種腔室工藝 和硬體（例如傳送機、檢測器、電動機、流體輸送設備等）， 並且用於監視系統工藝和腔室工藝（例如基板位置、工藝時 間、檢測器信號等）。該記憶體連接到CPU，並且該記憶體 21 201234622 ° s多種各易獲得的記憶體，諸如隨機存取記憶體 :RAM)、唯讀記憶體（R〇M)、軟碟、硬碟，或者本端的或 遠端的任意其他形式數位記憶體。軟體指令和資料可被編碼 並儲存在記憶體内，用於指示CPU。支援電路也連接到CPU， 用於以常規方式支援處理器。支援電路可包括緩存、電源、 時鐘電路、輸入/輸出電路、子系統等。系統控制器Μ可讀 的，式（或者電腦指令）確定在基板上執行哪個任務。理想 的是’程式是系統控制器778可讀的軟體，並且該軟體包括 代碼肖以產生並儲存基板位置資訊、各受控部件的移動順 序基板檢查系統資訊和上述的任意組合中的至少一個。 圖9A至圖9B是處理組969A和969B的示意性等角視 圖，該處理組969A和9698與處理組769相似，並且該處理 組969A和969B能夠用在處理系統7〇〇中。圖9八圖示了具 有傳送機987A的處理組969A ,該傳送機987A具有供給捲 筒（feed spo〇l)988 和捲取捲筒（take_up sp〇〇1)989。供給捲筒 和捲曲捲筒989適配於供給材料99〇並保持材料99〇 , 該材料990跨台板991定位。材料99〇限定處理平面p，在 處理期間基板350被定位於該處理平面p上。材料99〇是多 =材料（諸如蒸騰材料），以允許空氣或者其他氣體穿過該 多孔材料，由此使基板350能夠經由真空保持在台板99ι 上，該基板350設置在該材料990 一側上，該真空在材料99〇 的相對側上產生。通常經由真空泵（未圖示）經由真空埠施 加真空，該等真空埠形成在台板991中。 22 201234622 圖9B圖示了處理組969B的另一實施例，該處理组969B 具有連續傳送機987B。傳送機987B包括供給輥（fee(j roller)992和空載輥（idler roller)993。供給報992和空載親 993適配於跨過台板991供給材料990，如圖9B t所示。應 知具有多於一個傳送機987B的處理組可含有多於一個供給 輥992和空載輥993。 台板991具有由材料990限定的基板支撐表面。在處理 頭中的處理期間，基板350被支撐在材料99〇上該處理頭 諸如圖7中所示的處理頭776。材料99〇 一般是多孔材料， 以使基板350能夠經由真空保持在台板991上該基板35〇 設置在該材料990的一側上，缽吉介产# u ,丨Λ W上这真空在該材料990的相對侧 上產生。 在處理期間’ #裝載和㈣基板350時，處理組969Α 和969Β -般保持為相同取向。由於當每個基板⑽從處理 ΓΓ裝载和卸制，前—傳送機構造（圖…消耗了材 :二’因此當處理組969〜 969Β保持為相同取向時和 月因而，=機構造相比，更優選連續的傳送機構造（圖9Β)。 並更換材料99〇“ c T在處理期間疋期地去除 續傳送_^目’在裝載和卸載每個基板35G期間連 的某)不會消耗材料"。。因此，在本發明 迴圈時間、日 中所示的連續傳送機系統可提供 里和良品率方面的優點。 23 201234622 通過本發明，由於以基板背面設置在處理平面上的情況 下將基板定位在印刷站的第一印刷單元上，因此解決了污染 基板正面的問題。因而，保護了基板正面在印刷應用之前不 會觉到無意設置在處理平面上的任何剩餘膠的影響。因為使 用了多個膠源的緣故，可先於背面，印刷基板正面並使基板 正面金屬化，所以最初可將基板背面設置在處理平面上。多 個膠源允許從正面使該等孔金屬化，而從背面使匯流條金屬 化；與必須同時使孔和匯流條金屬化的現有工藝不同（且由 此’金屬化是從基板背面進行的）。 儘管當將基板背面向下地定位在用於印刷的平面上時， 處理平面可能含有一些多餘膠或者其他污染物，但是可能接 觸奇側的任何污染一般是可忽略的。由於經調配的印刷膠成 分’減少了在基板背側上的膠污染’而且，由於大部分背面 都被匯流條和背面金屬化覆蓋，因此基板背面上的任何污染 都不會有很大影響《此外，本發明的實施例提供了在匯流條 和金屬化之間的雷射劃線，以減少或者防止由於存在金屬膠 污染而可能出現的分流（shunting )。 本發明的其他優點包括以多層在基板正面上印刷指狀 物。以多層形成指狀物能使指狀物的縱橫比增加，從而減少 了在基板正面上的遮擋，同時減小了因指狀物厚度增加導致 的通過指狀物的電阻率。 雖然前述内容針對本發明的實施例，但是在不偏離本發 24 201234622 明的基本範圍的情況下’可設計出本發明的其他和進—牛 實施例，並且本發明的範圍經由以下的權利要求確定。乂的 【圖式簡單說明】 為了更詳細理解本發明的上述特徵，藉由參考實施例。 獲得簡要概述如上的本發明的更特定描述，一 可 二頁施例在附 圖中圖示。但是應注意，附圖僅圖示了本發明的典型實施 例，因此附圖不應視為限制本發明的範圍，本發明可允許其 他等效實施例。 ~ 圖1是標準太陽能電池的示意圖。 圖2Α和圖2Β是印刷工藝期間太陽能電池的示意圖。 圖3是經由本發明的一個實施例形成的太陽能電池的示 思圖。 圖4是經由本發明的實施例形成的太陽能電池的示意性 截面圖。 圖5是根據本發明一個實施例在印刷工藝期間基板的示 忍性圖示。 圖6是根據本發明另一實施例在印刷工藝期間基板的示 意性圖示。 25 201234622 圖7是處理系統的等角示意圖。 圖8是圖7中所示處理系統的示意性平面圖。 圖9 A和圖9B是圖7處理系統的處理組（nest)的等角 示意圖。 為了便於理解，在可能的情況下，使用相同元件符號來 表示所有圖中共有的相同元件。應知一個實施例的元件和特 徵可有利地併入其他實施例中而無需進一步敘述。 【主要元件符號說明】 B背面 C太陽能電池 D 沉積物 F正面 Μ 金屬膠 Ρ處理平面 1位置 2位置 3位置 4位置 114匯流條 116指狀物 150基板 26 201234622 218 支撐件 250A 基板 250B i 基板 316 指狀物 350 基板 414 匯流條 417 背面金屬化 421 ρ型基區 422 η型發射區 423 ρ-η結區 516 集電指狀物 551 孔 552 含銀導電膠 553 含銀導電膠 554 導電膠 555 含銘膠 556 絕緣元件 560 操作 561 操作 562 操作 563 操作 564 操作 565 操作 566 操作 201234622 616 金屬化的集電指狀物 670 操作 671 操作 672 操作 673 操作 674 操作 675 操作 700 基板處理系統 767 輸入傳送機 768 致動器組件 769 處理組 776 處理頭 111 輸出傳送機 778 系統控制器 779 輸入傳送機 780 排出傳送機 781 烘爐 782 檢查系統 783 照相機 785 致動器 786 傳送帶 969A 處理組 969B 處理組 987A 傳送機 28 201234622 987B 傳送機 988供給捲筒 989捲取捲筒 990材料 991台板 992供給輥 993空載輥In 563, 'using silver-containing thunder | a P gel 552 to metallize the hole (operation 563) and printing the silver on the collector finger 5 1 6 , the second layer of the work I3 (operation 562 ). Thus, the collector fingers 5 16 are formed using two sub-poles, each of which forms a different layer of the set 201234622 electrical fingers 516. An advantage of the dual layer collector fingers 516 is that the second printing on the collector fingers 516 increases the ratio (i.e., aspect ratio) between the height and width of the collector fingers 516. The two-layer current collecting fingers 516 having a reduced width can be printed while still providing a sufficient current transfer path (e.g., a sufficiently low resistivity) due to the increased height of the fingers 5 16 . By forming the collector fingers 516 having a reduced width, the surface area of the light receiving surface that is blocked by the collector fingers 516 is thereby reduced. The present invention utilizes two different glues (e.g., silver-containing conductive paste 552 and silver-containing conductive paste 553) for printing on the front side of the substrate, thereby allowing the composition of each of the silver-containing glues 5 52, 5 53 to be suitable for a particular application. For example, a glue having a suitable viscosity (i.e., containing silver paste 552) may be selected for metallization of the holes 551 to fill the through holes or deposit the glue on the inner surface of the through holes to avoid the use of suction. By avoiding the use of suction, the printing process is simplified and the possibility of contaminating the surface of the support is reduced. Conversely, the viscosity of the silver-containing glue 553 can be greater than the viscosity of the silver-containing glue 552 to prevent the silver-containing glue 553 from "flowing" when the silver-containing glue 553 is printed onto the front surface F of the substrate 350. Moreover, depending on the desired conductivity value, regardless of the glue used for the bus bar 414 (illustrated in operation 564), the silver-containing glue 552 can also be selected for the aperture 551, and the glue for the bus bar can be selected as the contact. gum. In particular, an ideal contact paste based on silver and aluminum for making ia. bus bars, for example, makes it easy to contact a ribbon wire or a wire carrying current. Moreover, although the illustrated operations 562 and 563 occur simultaneously, it is understood that the holes 551 can be metallized prior to the P-layer first collector fingers 516, or vice versa. ~ 15 201234622 After operations 562 and 563, and prior to operation 564, the substrate 350 is flipped, for example using a robot, and the substrate is positioned on the second processing plane P of the second printing unit such that the front side F is placed in the second processing On the plane p. In the case where the back surface B of the substrate 350 faces the printing device, the bus bar 414 is printed on the back surface B using a third conductive paste 554, which is in electrical contact with the metallization hole 551, which contains silver and aluminum. . In operation 565, with the back side B still facing the printing device, the fourth aluminum-containing glue 555 is used to metallize the back side B in a region not covered by the bus bar 414 to form the back side metallization 471. Except for the small gap or spacing between the backside metallization 417 and the bus bar 414, substantially the entire back surface B of the substrate 35 is covered by the backside metallization 417 and the bus bar 414, which facilitates the back metal. Electrical isolation of 417 and bus bar 414. In some embodiments, the method also provides a processing operation 566 by which the insulating element 5S6 is scribed between the (bus bar 414) and the backside metallization 417 on the back side of the substrate 35, using the processing operation 566, Electrical isolation is formed between the back metallization and the bus bars 4 14 . Figure 6 is a schematic illustration of a substrate during a printing process in accordance with another embodiment of the present invention. In operation 670, the substrate 35 is positioned on a processing plane P of a printing unit, such as a single crystal germanium substrate having a hole 551 extending from the front surface F to the back surface b. The silver-containing conductive paste 5S2 is printed from the front surface F of the substrate 350 in operation 671 to metallize the holes 5. The holes 551 can be made by filling the holes 551 with a silver-containing conductive paste 552, or by applying a silver-containing conductive paste 552 to the inner surface of the holes 551 and leaving openings 16 201234622 through the holes 551. Chemical. In operation 672, a silver-containing conductive paste 553 is printed on the front side F of the substrate 350 to form metallized collector fingers 616. The metalized collector fingers 616 are in electrical contact with the metallized vias 551 and extend from the metallized vias 551 in all directions. Although operation 671 is illustrated to occur prior to operation 672, it should be understood that operation 672 can occur after operation 671. Moreover, in contrast to operations 561, 562, and 563 of FIG. 5, the metallized collector fingers 616 of FIG. 6 contain only a single metal layer printed using a single glue, rather than the multilayer current collection fingers as described with reference to FIG. The object 516 is returned to FIG. 6. After operation 672 and prior to operation 673, the substrate 35 is flipped face down on the second processing plane P of the second printing unit. In the case where the back surface B of the substrate 350 faces the printing device, the bus bar 414 is printed on the back surface b using the third conductive paste 554, and the back surface B is in electrical contact with the metallized hole 551. The third conductive paste 554 includes silver. And aluminum. In operation 674, the back side B is metallized using a fourth aluminum-containing glue 555 in a region not covered by the bus bar 414 with the back side B still facing the printing device to form the back side metallization 417. Thus, backside metallization 417 and bus bar 414 cover substantially the entire back side b of substrate 350. However, a small gap is left between the backside metallization 417 and the bus bar 414 to maintain electrical isolation between the backside metallization 417 and the bus bar 414. In some embodiments, the method includes an operation 675 in which an insulating member 556' such as a trench is scribed between the bus bar 414 and the back metallization 417 on the back side of the substrate 35〇 to Metallization is electrically isolated from bus bar 414. 17 201234622 Referring to Figures 5 and 6, in operations 562, 563 (Figure 5) and operation (7) (after the drawings - in some embodiments, the substrate 35A is positioned on the second processing plane while the substrate is flipped so that The second substrate 350 is provided on the initial processing plane P. The f φ of the two substrates 35G is clamped on the initial processing plane, thereby enabling the process loop to proceed faster. Figure 7 Schematic of the substrate processing system 7GG The isometric view can process the substrate in accordance with the method of the present invention in the substrate processing system 700. (4) The system includes two input conveyors 767, an actuator assembly 768, a plurality of processing groups 769, a plurality of processing heads 776, Two output conveyors 777, and a system controller 778. The input conveyors 767 are configured in a parallel processing configuration such that each input conveyor can receive an unprocessed substrate from an input device such as the input conveyor 779. 350' and each input conveyor transfers each unprocessed substrate to a processing group 769 that is coupled to the actuator assembly 768. Further, the output conveyor 777 is configured to be parallel such that each output is transmitted Machine can The processed substrate 769 is received from the processing group 769, and each of the output conveyors transfers each processed substrate 350 to a substrate removing device such as a discharge conveyor 78. Each of the discharge conveyors 78 is suitable The substrate 350 is disposed to be conveyed through an oven 781 to cure the material deposited on the substrate 350 via the processing head 776. The system 700 can also include an inspection system 782 that is adapted to position and before and after processing. The substrate 350 is inspected. The inspection system 782 includes one or more cameras 783 that are positioned to inspect the substrate 350' that is positioned in the loading/unloading positions "1" and "3", 18 201234622 As shown in 7 and 8. Inspection system 782 typically includes at least one camera 783 (e.g., a CCD camera) and other electronic components that are capable of locating, inspecting, and transmitting the results to system controller 778. In one example, The inspection system 782 is adapted to position the certain features of the input substrate 35' and transmit the inspection results to the system controller 778 for analysis of the substrate 35 The system controller 778 can determine that the substrate 350 is positioned below the processing head 776 prior to processing the substrate 35. In another example, the inspection system 782 inspects the substrate 35〇 to enable removal of damage from the production line. Substrate 3 50. Furthermore, it is understood that each of the processing groups 769 can contain a lamp, or other similar optical radiation device, to illuminate the substrate 350' positioned on the processing group such that the substrate 35 can be more easily Inspection system 782 checks. System 700 is a screen printing processing system, and processing head 776 includes screen printing components configured to screen print a patterned layer of material, such as a conductive paste, on substrate 35. 〇上. In the case of screen printing, the processing head 776 is used to print different glues on the front side F and the back side B of the substrate 35. The glues include glues 552, 553, 554 and 555 (as shown in Figure 5). Alternatively, it is contemplated that the system 700 can be an inkjet printing system, and the processing head 776 includes inkjet printing components that are configured to deposit a patterned layer of material onto the substrate 350. A schematic plan view of the system 700 depicted in FIG. Figure 8 illustrates the system 700 having two processing groups 769 (in positions "L and "3"), each processing group 769 being positioned to transfer the processed substrate 350 to the output conveyor 777 and The unprocessed base 19 201234622 board 3 50 is received from the input conveyor 767. Thus, in system 7A, substrate movement is generally along path "A" as illustrated in Figures 7 and 8. In this configuration, each of the other two processing groups (in positions "2" and "4") is positioned below processing head 776 to enable unprocessed substrates 35 located on respective processing groups 769. Processing is performed on top (for example, screen printing or inkjet printing). The parallel processing configuration of system 7〇〇 allows for increased processing power with minimal processing system footprint. Although system 700 is depicted as having two processing heads 776 and four processing groups 769, it is to be understood that system 700 can include other processing heads 776 and/or processing groups 769 without departing from the scope of the present invention. The two heads 776 utilized in the system 700 are conventional screen print heads commercially available from Applied Materials, Italia, Sr., which are adapted for screen printing. The material is deposited on the surface of the substrate 350 in a desired pattern during processing, which is placed on the processing group 769 at position "2" or "4". However, it will be appreciated that other sets or other supports may be used to practice the embodiments of the invention described herein. Processing head 776 includes a plurality of actuators 785 (e.g., stepper motors or servo motors). The plurality of actuators are in communication with system controller 778. Actuator 785 can be used to adjust the position and/or angular orientation of a screen printing mask (not shown) with respect to substrate 35A, which is disposed within processing head 776. The screen printing mask is generally a metal sheet or a metal sheet 'the metal sheet or sheet has a plurality of holes, grooves or other pores' to the upper surface of the substrate 350. The pattern and position of the screen printing material' The metal sheet or metal plate is formed. The screen printing material may comprise a conductive ink or a conductive paste, a dielectric ink or dielectric 20 201234622 glue, a dopant gel, an etch gel, one or more mask materials or other conductive materials or dielectric materials. Typically, the screen printing pattern to be deposited onto the surface of substrate 350 is automatically aligned with substrate 350 by using actuator 785 and information to orient the screen printing mask. This information is provided by system controller 778. Self-checking system 782 receives. In one embodiment, the processing head 776 is adapted to deposit a metal-containing or dielectric-containing material on a solar cell substrate having a width between about 125 mm and about 156 mm and a length of about 70 mm and about Between 156 mm. The input conveyor 767 and the output conveyor 777 include two conveyor belts 786 for supporting the substrate 35 by using an actuator and transferring the substrate 35 to a desired location within the system 700. The actuator and system controller 778 connected. Although FIGS. 7 and 8 generally illustrate a substrate transfer system having two conveyor belts 786, other types of transfer mechanisms can be used for performing the same substrate transfer function and positioning function without altering the basic scope of the present invention. . Moreover, it should be understood that the input conveyor 767 and the output conveyor each may have one conveyor belt or may have more than two conveyor belts. System controller 778 facilitates control and automation of overall system 700, and system controller 778 can include a central processing unit (CPU), memory, and support circuitry (or I/O). The CPU can be one of any form of computer processor used in an industrial setting for controlling various chamber processes and hardware (eg, conveyors, detectors, motors, fluid handling equipment, etc.) and Monitor system processes and chamber processes (eg substrate position, process time, detector signals, etc.). The memory is connected to the CPU, and the memory 21 201234622 s various easily available memories, such as random access memory (RAM), read only memory (R〇M), floppy disk, hard disk, or Any other form of digital memory at the local or remote end. Software instructions and data can be encoded and stored in memory to indicate the CPU. The support circuit is also connected to the CPU for supporting the processor in a conventional manner. Support circuits may include buffers, power supplies, clock circuits, input/output circuits, subsystems, and the like. The system controller readable, (or computer instructions) determines which task to perform on the substrate. Desirably, the program is a software readable by the system controller 778, and the software includes code to generate and store substrate position information, movement sequence substrate inspection system information for each controlled component, and any combination of the above. Figures 9A-9B are schematic isometric views of processing groups 969A and 969B that are similar to processing group 769, and that processing groups 969A and 969B can be used in processing system 7A. Figure 9 illustrates a processing group 969A having a conveyor 987A having a supply spool 988 and a take-up spool 989. The supply reel and the crimp reel 989 are adapted to supply material 99 〇 and hold the material 99 〇 which is positioned across the platen 991. Material 99 〇 defines a processing plane p on which substrate 350 is positioned during processing. The material 99〇 is a multi-material (such as a transpiration material) to allow air or other gas to pass through the porous material, thereby enabling the substrate 350 to be held on the platen 991 via a vacuum, the substrate 350 being disposed on the side of the material 990 Above, the vacuum is created on the opposite side of the material 99〇. Vacuum is usually applied via a vacuum pump via a vacuum pump (not shown), which is formed in the platen 991. 22 201234622 FIG. 9B illustrates another embodiment of a processing group 969B having a continuous conveyor 987B. Conveyor 987B includes a feed roller (je) 992 and an idler roller 993. Supply 992 and no-load 993 are adapted to feed material 990 across platen 991, as shown in Figure 9Bt. It will be appreciated that a processing group having more than one conveyor 987B may contain more than one supply roller 992 and no-load roller 993. Platen 991 has a substrate support surface defined by material 990. During processing in the processing head, substrate 350 is The processing head is supported on a material 99 such as the processing head 776 shown in Figure 7. The material 99 is generally a porous material to enable the substrate 350 to be held on the platen 991 via a vacuum, the substrate 35 being disposed on the material 990 On one side, the vacuum is generated on the opposite side of the material 990. During the processing period ## loading and (4) substrate 350, the processing groups 969Α and 969Β remain the same Orientation. Since each substrate (10) is loaded and unloaded from the processing cassette, the front-conveyor configuration (Fig....consumed material: two' so when the processing group 969~969Β remains in the same orientation and month, thus the machine configuration In comparison, a continuous conveyor configuration is more preferred ( 9Β) and replace the material 99〇 “c T during the processing period to remove the continuous transfer _ ^ ' during the loading and unloading of each substrate 35G during the connection) does not consume material ". Therefore, in the present invention The continuous conveyor system shown in the lap time and day can provide advantages in terms of yield and yield. 23 201234622 By the present invention, the first substrate is positioned at the printing station with the back surface of the substrate disposed on the processing plane On the printing unit, the problem of contaminating the front side of the substrate is thus solved. Thus, the effect of any remaining glue unintentionally placed on the processing plane is not felt before the printing application is applied, because of the use of multiple glue sources, The front side of the substrate can be printed on the back side and the front side of the substrate can be metallized, so that the back side of the substrate can be initially placed on the processing plane. A plurality of glue sources allow the holes to be metallized from the front side and the bus bars to be metallized from the back side; Unlike existing processes that must simultaneously metallize the holes and bus bars (and thus 'metallization is performed from the back side of the substrate). When positioned on a flat surface for printing, the processing plane may contain some excess glue or other contaminants, but any contamination that may contact the odd side is generally negligible. Since the formulated printing adhesive composition 'reduced on the back of the substrate Glue contamination on the side 'and, since most of the back side is covered by the bus bar and back metallization, any contamination on the back side of the substrate will not have a significant impact." Furthermore, embodiments of the present invention provide for bus bars and Laser scribing between metallizations to reduce or prevent shunting that may occur due to the presence of metal glue contamination.Other advantages of the invention include printing the fingers on the front side of the substrate in multiple layers. Forming the fingers in multiple layers increases the aspect ratio of the fingers, thereby reducing occlusion on the front side of the substrate while reducing the resistivity through the fingers due to the increased thickness of the fingers. Although the foregoing is directed to embodiments of the present invention, other embodiments of the present invention may be devised without departing from the basic scope of the present invention, and the scope of the present invention is determined by the following claims. determine. BRIEF DESCRIPTION OF THE DRAWINGS In order to understand the above features of the present invention in more detail, reference is made to the embodiments. A more general description of the invention as outlined above is obtained, and a two-page embodiment is illustrated in the accompanying drawings. It is to be understood, however, that the appended claims ~ Figure 1 is a schematic diagram of a standard solar cell. 2A and 2B are schematic views of solar cells during a printing process. Fig. 3 is a view showing a solar cell formed through an embodiment of the present invention. Fig. 4 is a schematic cross-sectional view of a solar cell formed through an embodiment of the present invention. Figure 5 is a diagrammatic representation of a substrate during a printing process in accordance with one embodiment of the present invention. Figure 6 is a schematic illustration of a substrate during a printing process in accordance with another embodiment of the present invention. 25 201234622 Figure 7 is an isometric view of the processing system. Figure 8 is a schematic plan view of the processing system shown in Figure 7. 9A and 9B are isometric views of a processing group (nest) of the processing system of Fig. 7. For the sake of understanding, the same component symbols are used to denote the same components common to all the figures, where possible. It will be appreciated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. [Main component symbol description] B back surface C solar cell D deposit F front side Ρ metal enamel processing plane 1 position 2 position 3 position 4 position 114 bus bar 116 finger 150 substrate 26 201234622 218 support 250A substrate 250B i substrate 316 Finger 350 substrate 414 bus bar 417 back metallization 421 p-type base region 422 n-type emitter region 423 ρ-η junction region 516 collector finger 551 hole 552 silver-containing conductive paste 553 silver-containing conductive paste 554 conductive paste 555 Ingredients 556 Insulating Components 560 Operation 561 Operation 562 Operation 563 Operation 564 Operation 565 Operation 566 Operation 201234622 616 Metalized Collector Finger 670 Operation 671 Operation 672 Operation 673 Operation 674 Operation 675 Operation 700 Substrate Processing System 767 Input Conveyor 768 Actuator Assembly 769 Processing Group 776 Processing Head 111 Output Conveyor 778 System Controller 779 Input Conveyor 780 Discharge Conveyor 781 Oven 782 Inspection System 783 Camera 785 Actuator 786 Conveyor Belt 969A Processing Group 969B Processing Group 987A Conveyor 28 201234622 987B Conveyor 988 for 989 990 material roll take-up reel 991 platen roller 992 feed roller 993 load