201214744 六、發明說明： 【發明所屬之技術領域】 本發明係關於一種具有燒製之後側接觸件的一太陽能電 池之製造方法，且係關於用此一方法製造的一電池。特定 言之，本發明係關於-種太陽能電池之製造方法，該太陽 能電池具有燒製之後側接觸件及具有貫穿該電池之通孔， 以用於使定位於-前側的射極層接觸定位於後側的匯流 條。 【先前技術】 太陽能電池具有兩側：一前側，其相對於光而導向·，及 -後側’其通常具有一至少部分金屬化的表面。在該等側 之間’存在不同層之一堆疊’該等不同層執行不同任務， 諸如抗反射層、收集光的一層、具有一空間電荷層的一p_ η接面&用於建立至該太陽能電池之外部之接觸的接觸 層、。通常可辨別前侧接觸件及後側接觸件，其中前側接觸 件連接至射極層，且後側接觸件連接至基板主體。為在該 前側上收集電荷載子，並排配置狹窄的所謂指狀部，其由 所謂的㈣條料。後者匯流條提供焊㈣域，外部線可 焊接於其上。 因為一太陽能電池之效率強烈取決於可由光照射的區 域’故期望減少在該前側上由金屬覆蓋且因此由指狀部及 匯流條阻擋的區域。對此的一解決方案係提供通孔，其等 將許多前側指狀部之金屬連接至定位於該後側上的一匯流 條。此等電池稱為金屬穿透式背電極電池，或卿丁電 157945.doc 201214744 也 替代解決方案甚至並不提供前側指狀部，但提供較 高數目之緊密間隔的通孔，其等具有半導電的側壁，因此 作為用於連接前側與後侧的構件。因為此等孔被摻雜，且 因此為導電的，此等電池稱為射極穿透式背電極電池，或 EWT電池。再一次強調，提供相應之焊接區域的後側配置 之匯流條及指狀部隨後收集電荷載子。 此等從後側接觸的貫穿式太陽能電池的製造需要複雜的 耘序序列。習知太陽能電池處理步驟對於貫穿式基板的調 適係相當苛求的。當通孔在任意其他處理步驟之前插入至 該基板時’在對比於沒有孔的f池時，所有隨後的處理必 /頁考慮此等貝穿式電池之不同的物理特性。此對於該基板 的易碎性係尤其相關的，該基板的易碎性在貫穿之後明顯 增加。 另一缺點在於以下事實，即，該等指狀部之導電率及 (對於MWT電池）該等金屬化通孔之導電率係不令人滿意 的。此係因為網印係用於塗敷導電膏的典型程序，該導電 膏形成尤其該等指狀部，且其對於MWT電池，亦經壓入 至通孔中以達成導電率。該膏本身不僅含有導電成分，且 亦含有其他程序相關之成分，此繼而減少導電率。此外， 在该膏之溫度引致處理期間可出現空隙。因為粘性膏趨向 於溶解，當產生狹窄的指狀部時，其可達成的寬度被限 制，從而限制例如指狀部之一矩形縱向截面的縱橫比。為 補償低導電率，通孔的數目必須增加。再者，即使一高縱 橫比亦僅在指狀部與基板之間提供一較小接觸面積。因 157945.doc 201214744 此，期望藉由提供一更好的可控制之指狀部截面幾何形狀 x及更向導電率的其他技術替代此網印前側金屬化，亦 期望一可能存在的通孔金屬化。 日又—缺點在於以下事實，即，當在初始摻雜後製作通孔 時，需要另一摻雜步驟以達成孔側壁的一令人滿意之導電 率。實行此額外步驟需要額外的努力料間，此明顯不是 令人期望的。 【發明内容】 匕本七月之目的係提供具有經燒製之後側接觸件及具 有貧穿電池之通孔的一太陽能電池之製造方法，該方法避 免當前最先進技術之缺點。特定言之，該方法應減少將一 製程從不具有通孔之基板調適至具有通孔之基板的努力。 程序應進-步達成可能存在的狹窄指狀部之幾何形狀的一 更好可控性，且改良尤其前側指狀部及/或金屬穿透式背 電極通孔兩者之導電率。應減少程序步驟之數目，且尤盆 應減少對於已貫穿之基板的程序步驟之數目。 【實施方式】 根據本發明之方法尤其用於製造具有燒製之後側接觸件 及具有貫穿電池之通孔的—太陽能電池。對於此—電池之 間’同時進行該等通孔 同義術°#係「具有燒製接觸件之從後側接觸之太陽能電 池」。根據本發明，在製作通孔期 的摻雜。 I57945.doc • 6 - 201214744 (a) 提供該太陽能電池基板。此基板通常由矽組成；然 而’其他材料，尤其玻璃、陶瓷及塑膠可用作一基板 材料。 (b) 將前側及/或後側紋理化。此選用但為典型之步驟係關 於改良（若干）電池表面之吸收特性。 (c) 藉由擴散而摻雜以產生射極。此通常係藉由磷實現以 在P型基板上達成一η摻雜層。一般而言，該摻雜層具 有與主體材料相反的極性《該程序通常在一管爐中實 行。此步驟在隨後稱為「主體擴散」。 (d) 在磷擴散之後，視需要移除一可能存在之玻璃層，例 如PSG(磷矽酸鹽玻璃）。此層可在主體摻雜步驟期間產 生。 (e)視需要但實質上總是在前側上沈積或生長一單一或多 層系統以用於鈍化及抗反射目的。減少反射對於達成 高效率很重要。純化幫助減少重組，因此亦增加太陽 能電池之效率。典型層包括氮化矽及/或二氧化矽。 ⑺金屬化後側以產生接觸件。通常藉由網印執行金屬 化。η型區域之接觸件通常由銀（Ag)組成，p型焊接區 域之接觸件由銀峰gA1)組成，且p型區域之接觸件由 鋁（A1)組成。 („觸件。在仍然潮濕或部分乾燥但具脆性的 八而門可能存在㈣化㈣藉“燒製膏的成 刀而開口，因此4許主體材料與金屬化接觸 157945.doc 201214744 一直接電接觸。 ⑻至少在後側上執行一邊緣隔離。可使用乾式或濕式技 術執行此步驟。當使用濕式技術時，通常在主體摻雜 與純化步驟之間實行該步驟，而乾式技術在隨後之處 理步驟（諸如網印）之後亦係適宜的，或甚至作為一最 終步驟。通常使用雷射執行邊緣隔離。 應注意，提及之步驟的實際序列在某些情況中可改變， 意謂在此呈現的次岸祐非& 斤立非強制的，及/或可能需要額外的 步驟以製造成品。 如前面提及’通孔係必需的，以提供基板之前側與後側 之間的電接觸。 通常，通孔係在-非常早階段插入基板中，即，在上文 ，及之步驟⑻之則。結果，所有隨後步驟在貫穿式基板上 實行，帶來上文描述之缺點。另—方面，已存在的通孔可 在主體擴散步驟期間與基板的剩餘部分一起摻雜。儘管使 得此等孔的一後續分離摻雜可能 』此為非必需的，但是其在當 通孔之摻雜應不同於主體摻雜 八 田 心雜之情况中仍然可能是令人期 望的，例如，以達成不同蓮番·安 u導電率、摻雜劑濃度或摻雜劑類 型。 若通孔的製作在主體摻雜（步驟（顿進行，則-額夕M 雜步驟係必需的，以達成孔側壁之—令人滿意的導電率〇 根據當前最先進技術’此額外換雜步驟在製作通孔自身戈 後實行’通孔自身的製作例如藉由雷射鑽孔進行。相反， 根據本發明，關於通孔的額外換雜步驟與通孔之製作㈣ 157945.doc 201214744 入、引入、開口、鑽孔）同時實行。 應注意，同時製作及摻雜係獨立於通孔之製作的實際時 刻’此亦係為什麼此步驟不在上文的程序序列⑷至附 展不。此意謂組合的鑽孔/摻雜步驟不僅可在上文提及之 步驟⑷之後實行，且亦可在其之前或甚至在其期間實行。 因此’即使尚未進行藉由擴散步驟的射極摻雜，實行組合 的鑽孔/摻雜步驟亦可為有利的，因為通孔的壁可達成比 ?板之剩餘部分更好(更高)的_導電率(因為通孔經摻雜兩 人，而基板的剩餘部分僅經摻雜一次）。此外，對於兩個 t雜y驟之各者可使用不同的摻雜劑及/或摻雜次數。另 外，可與主體摻雜步驟同時實行額外摻雜步驟，使得例如 可在通孔内及通孔外達成不同的摻雜結果。 對於通孔之組合製作/摻雜，較佳使用液體喷流引導雷 射處理技術，尤其LCP(雷射化學處理）及LIp(光致電鍍）， 其等在稍後予以更詳細描述。 根據本如明之一較佳實施例，通孔之製作及摻雜係藉由 雷射化學處理（LCP)進行，Lcp係液體喷流引導雷射處理 之-特殊形式’其使用含有摻雜劑的液體而非水，或其係 藉由乾式雷射處理而執行。在此，兩項技術係使用含有摻 雜劑源的液體。 亦可稱為及描述為「液體噴流引導雷射處理」之LCp使 用耦合進入至一液體噴流且由該液體喷流引導的一雷射光 束°雷射提供主要用於熔化及燒蝕該雷射經導向所至之表 面的能量。雷射亦可遞送對於化學反應所需的能量，或增 157945.doc 201214744 強化學反應。該液體本身含有在雷射照㈣間與表 照射經導向至其上)化學相互作用的成分。典型的液體： 水（在某些材料上的氧化特性），或含有換雜劑之液體，使 得例如-通孔可同時被鑽孔及摻雜。因為雷射與不同材料 不同地相互作用，例如當到達-先前產生之金屬層(例 如，通孔之後側接觸件）時停止鑽孔係不成問題的。然 而，取決於具體隨後的程序步驟，此_通孔可甚至經鑽孔 -直通過基板及接觸件，且㈣提供至定位於前側之射極 的電接觸。 -替代「乾式」技術亦使用一雷射光束，其並不由一液 體喷流引導，但直接撞擊待處理之表面。然而，為達成處 理表面的化學反應或改質，纟雷射處理期間或在其之前將 含有必需化學成分(諸如摻雜劑)之一薄液體層塗敷至該表 面上，因此在實際雷射照射之前實現乾燥。碟酸(H3p〇4) 可有利地使用為此一液體。 兩項技術之目標係製作-通孔且同時摻雜該通孔，使一 可能存在之鈍化層開口，以用於涉及金屬化之進一步處 理’及/或同時使因此暴露的表面改質。然而，此並不暗 示在-太陽能電池的製造期間該等技術限制於此一用途。 根據本發明之另-實施例，通孔的製作在產生—層氮化 石夕及/或二氧化石夕層之後進行。通常需要此一層以達成鈍 化及抗反射目的（亦參見上文的步驟（e))。 根據當前最先進技術，通孔係在—非常早階段插入基板 中，即，在上文提及之步驟（b)之前。結果，所有隨後步驟 157945.doc •10- 201214744 在貫穿式基板上實行，帶來上文始 明制„ ^ ^相㈣。根據本發 ’ I作通孔的程序可在-更日切段執行，即，在 觸件之後執行。因此，上女福万 、 仃U此上文k及之步驟⑷至⑻的大部分 (若並非全部)在標準(即，非貫穿)基板上實行。此等程序 步驟之調適不再適用，或小規模適用。通常易碎之基板的 破損率明顯減小。 另一優點係現可容易地達成一所謂選擇性射極的使用。 一選擇性射極特徵在於為（例如，至指狀部之）金屬化接觸 保留的區域經高度摻雜，因此提供—低薄片電阻（例如， 20歐姆/平方）及—良好的金屬♦接觸，且代表太陽能電池 之被照明表面的剩餘區域摻雜較少，因此提供一較高薄片 電阻（例如，12〇歐姆/平方）及較低的重組。根據本發明， 該選擇性射極係在製作孔之前生產，使得可更容易地製造 太陽能電池，尤其具有通孔及選擇性射極的MWT電池。 此繼而增加電池效率。 在視需要存在前側指狀部之情況中，對於此等前側指狀 部，上文提及之執行於通孔上的Lcp處理及摻雜較佳係與 局部摻雜組合用於一純化層的前側開口。 根據一進一步較佳之實施例，該等通孔之金屬化藉由光 致電鍍（UP)或無電式電鍍而進行。至於上文提及2Lcp處 理及摻雜，此金屬化方法有利地使用於視需要存在之前側 指狀部。 如前面提及’通常使用於太陽能電池製造的網印膏之導 電率以及可達成的幾何形狀係不足的。可用促成一純且因 157945.doc 201214744 此極低電阻之金屬化層的電鍍技術達成一更好的導電率。 此外，不再使用隨後的燒製。 然而大致上，所有可能類型之電鍍技術可有利地使用於 本發明，尤其較佳為熟知之光致電鍍技術或使用無電式電 鍍。當照射製造中的一太陽能電池時，產生電荷載子且電 荷載子可將電流從一側傳導至另一側。將一側連接至一第 一電極，且使用一第二鍍槽電極，因此導致與電解液接觸 之電池表面的電鍍。此同樣適用於已使用LCP鑽孔及摻雜 的電池通孔，而一太陽能電池之經遮罩或非導電區域（諸 如鈍化區域）保持未電鍍。由此電鍍產生之典型金屬堆疊 為例如 Ni-Ag、Ni-Cu-Sn 或 Ni-Cu-Ag。 無電式電鍍並不使用一外部電流，且亦可用於電鍍或強 化一太陽能電池之導電結構。 因為沒有金屬必須經過之高粘性相，金屬化結構之不僅 是導電率而且品質及幾何形狀之可控性均遠勝於使用膏可 達成者。儘官在製程中無法完全省略網印的使用，網印步 驟的數目明顯減小。例如，對於先前四個網印步驟係必需 的一電池，即，（1)對於後側射極匯流條及孔接觸件，（2) 對於基極焊接墊’（3)對於後側鋁區域’及（4)對於前側射 極接觸件’可省略第一及第四步驟，由於一更高的導電 率’不僅導致一更好的產品品質’而且亦導致節省部分含 銀且因此為昂貴的膏。此外，由雙側網印程序步驟所致之 電池的可此必需之翻轉亦可省略，導致進一步簡化程序且 減小破損之危險。再者，若執行一隨後燒製程序，^其〇 I57945.doc 12 201214744 經設計以「最佳化 雜性* 更少的要求’導致進_ 步減小程序複 二：τ電池，電鐘通孔之高導電率導致非常有利地減 電池表面上的必需之孔分佈密度。 根據本發明之另—實施例，待執行於後側上的至少—邊 ，隔離步《由液时流引導#射或其他（例如 處理進行。 ％ 邊緣隔離係必需的，以防止在不同極性之導電區域（諸 如太％能電池之陽極與陰極，即’前側射極與後側接觸 们之間的分流。若在上文之步驟⑷中描述之射極產生實 行於電池之整個表面上’則導電層不僅覆蓋前側及後側， 且亦覆蓋邊，緣。因此，邊緣隔離係必需的。㈣，較佳可 使用LCP或乾式t射處理執行其他必需之隔離步驟，例如 在前側上的一邊緣隔離步驟，或在後側射極與基極區域之 間的一接觸隔離步驟。 此程序步驟之典型的液體為水（Η")或氧化性液體。 根據另一實施例，邊緣隔離係使用濕式化學蝕刻而非 LCP來執行，且射極帶留在後側上，其上隨後進行射極匯 流條金屬化《帶區域可相應地經遮罩，使得僅在該等帶之 外的區域被開口，且帶區域仍由射極擴散覆蓋。 根據一進一步實施例，金屬化通孔直接被用作用於模組 製造之射極接觸件之焊接墊。在後側上不執行額外的射極 匯流條金屬化。此意謂在後側上不存在射極指狀部及/或 射極匯流條’但金屬化射極通孔被直接焊接至互連突片。 157945.doc 】3· 201214744 模組後部薄片可具焊接凸塊特徵，使電池分別對準該等通 孔。隨後，在模組後部薄片上的該等焊接凸塊被焊接至金 屬化通孔’且達成電池互連。在此的優點為在電池後側上 必須執行的材料及製造步驟較少，從而降低電池之成本。 在面板上的墊及/或對應區域可由一焊料覆蓋，該焊料在 加熱期間液化且當冷卻時在連接的位置固化。 根據一進一步實施例’射極之一控制回蝕在如上文描述 為步驟（C)之藉由擴散而摻雜以產生射極的步驟之後進行， 以增加薄片電阻。此選用步驟亦幫助改良藍色靈敏度，且 減乂表面重組效應，因為一高度摻雜之表面區域（無感層 (dead layer))經移除。因此，回蝕增強電池效率。可藉由 例如氫氟酸/確酸（HF_HN〇3)溶液，或藉由反應性離子^刻 (RIE)技術執行回触。 根據另-實施例，此外’後側拋光係在一通常存在之前 側鈍化之刖執行。此步驟有利地直接在選用的回蝕步驟之 後執行，或若未執行此回蝕，則在擴散步驟之後執行。拋 光導致一更平滑表面，且幫助減小重組損耗。 根據又另貫加例，額外或單獨地進行電池之後側之鈍 化。此在除上文提及之步驟（e)之外另外進行或代替步驟 (e)而進行，該步驟（e)目前為止僅提及前側。然而，若亦 進行前側鈍化，在步驟（e)之前或之後直接實行後側鈍化步 驟係有利的。亦可一次執行兩個步驟，即，鈍化整個基 板，例如，藉由將其浸入適當溶液中，或藉由使用pEcvD (電漿增強化學氣相沈積）。可行的層材料可為例如八12〇3、 157945.doc -14- 201214744201214744 VI. Description of the Invention: [Technical Field] The present invention relates to a method of manufacturing a solar cell having a side contact after firing, and to a battery manufactured by the method. In particular, the present invention relates to a method of manufacturing a solar cell having a side contact after firing and having a through hole penetrating the battery for positioning the emitter layer positioned on the front side The bus bar on the back side. [Prior Art] A solar cell has two sides: a front side that is oriented relative to light, and a - rear side that typically has an at least partially metallized surface. Between the sides, 'there is one of the different layers stacked', the different layers perform different tasks, such as an anti-reflective layer, a layer that collects light, a p_n junction with a space charge layer & a contact layer that contacts the outside of the solar cell. The front side contact and the rear side contact are generally discernible, wherein the front side contact is connected to the emitter layer and the back side contact is connected to the substrate body. In order to collect the charge carriers on the front side, a narrow so-called finger is arranged side by side, which is called a (four) strip. The latter bus bar provides a weld (four) field to which the outer wire can be soldered. Since the efficiency of a solar cell strongly depends on the area that can be illuminated by light, it is desirable to reduce the area covered by metal on the front side and thus blocked by the fingers and bus bars. One solution to this is to provide a through hole that connects the metal of the plurality of front side fingers to a bus bar positioned on the back side. These batteries are referred to as metal-transmissive back-electrode cells, or butyl 157945.doc 201214744. An alternative solution does not even provide front-side fingers, but provides a higher number of closely spaced through-holes, etc. The conductive side walls are thus used as members for connecting the front side and the rear side. Because such holes are doped and therefore electrically conductive, such cells are referred to as emitter-penetrating back electrode cells, or EWT cells. Again, it is emphasized that the bus bars and fingers that provide the rear side configuration of the corresponding weld zone then collect charge carriers. The manufacture of such through-cell solar cells that are contacted from the back side requires a complex sequence of sequences. Conventional solar cell processing steps are quite demanding for the through substrate. When the vias are inserted into the substrate prior to any other processing steps, all subsequent processing must take into account the different physical characteristics of the cell-through cells when compared to the f-cell without the holes. This is especially relevant for the friability of the substrate, the friability of which is significantly increased after penetration. Another disadvantage lies in the fact that the conductivity of the fingers and the conductivity of the metallized vias (for MWT cells) are unsatisfactory. This is because the screen printing is a typical procedure for applying a conductive paste which forms, in particular, the fingers, and which is also pressed into the through holes for the MWT battery to achieve electrical conductivity. The paste itself contains not only conductive components, but also other process-related components, which in turn reduces electrical conductivity. In addition, voids may occur during the temperature of the paste causing the treatment. Because the viscous paste tends to dissolve, the achievable width is limited when a narrow finger is created, thereby limiting, for example, the aspect ratio of the rectangular longitudinal section of one of the fingers. To compensate for low conductivity, the number of vias must be increased. Moreover, even a high aspect ratio provides a small contact area only between the fingers and the substrate. 157945.doc 201214744 Thus, it is desirable to replace this screen front side metallization by providing a better controllable finger cross-section geometry x and other techniques for more conductivity, and also to suggest a possible via metal. Chemical. Again, the disadvantage is due to the fact that when the vias are formed after the initial doping, another doping step is required to achieve a satisfactory conductivity of the sidewalls of the holes. Performing this extra step requires additional effort, which is clearly not desirable. SUMMARY OF THE INVENTION The purpose of this July is to provide a method of manufacturing a solar cell having a post-fired side contact and a through-hole that is lean through the battery, which avoids the shortcomings of current state of the art technology. In particular, the method should reduce the effort to adapt a process from a substrate having no vias to a substrate having vias. The procedure should further achieve a better controllability of the geometry of the narrow fingers that may be present, and improve the conductivity of both the front side fingers and/or the metal penetrating back electrode vias. The number of program steps should be reduced and the number of program steps for the substrate that has been traversed should be reduced. [Embodiment] The method according to the present invention is particularly useful for manufacturing a solar cell having a side contact after firing and a through hole penetrating the battery. For this - between the batteries, the through holes are simultaneously performed. The synonym is the "solar battery with the contact of the fired contacts from the rear side". According to the present invention, doping during the via period is made. I57945.doc • 6 - 201214744 (a) Provide the solar cell substrate. This substrate is usually composed of tantalum; however, other materials, particularly glass, ceramics and plastics, can be used as a substrate material. (b) Texture the front side and/or the back side. This optional but typical procedure is related to improving the absorption characteristics of the surface of the battery. (c) doping by diffusion to produce an emitter. This is typically achieved by phosphorus to achieve an n-doped layer on the P-type substrate. In general, the doped layer has a polarity opposite to that of the host material. The procedure is typically performed in a tube furnace. This step is referred to as "subject diffusion". (d) After the phosphorus has diffused, remove a possibly existing glass layer, such as PSG (phosphorite glass). This layer can be produced during the bulk doping step. (e) Deposit or grow a single or multi-layer system on the front side as needed for passivation and anti-reflection purposes, as needed. Reducing reflection is important to achieve high efficiency. Purification helps reduce recombination and therefore increases the efficiency of solar cells. Typical layers include tantalum nitride and/or hafnium oxide. (7) Metallizing the back side to create a contact. Metallization is usually performed by screen printing. The contacts of the n-type region are usually composed of silver (Ag), the contacts of the p-type pad region are composed of silver peak gA1), and the contacts of the p-type region are composed of aluminum (A1). („Contacts. Eight-doors that are still wet or partially dry but brittle may exist (4). (4) By opening the knife with a knife, so the contact between the main material and the metallization is 157945.doc 201214744 Contact (8) Perform an edge isolation on at least the back side. This step can be performed using dry or wet techniques. When using wet technology, this step is typically performed between the bulk doping and purification steps, while the dry technique is followed. The processing steps (such as screen printing) are also suitable, or even as a final step. Edge separation is usually performed using a laser. It should be noted that the actual sequence of steps mentioned may be changed in some cases, meaning This presentation of the sub-shore is not mandatory and/or may require additional steps to manufacture the finished product. As mentioned earlier, the 'through-hole system is required to provide electricity between the front side and the back side of the substrate. Contact. Typically, the via is inserted into the substrate at a very early stage, ie, above, and step (8). As a result, all subsequent steps are performed on the through substrate, bringing the above Disadvantages. In other aspects, existing vias may be doped with the remainder of the substrate during the bulk diffusion step. Although it is not necessary to have a subsequent separation doping of such holes, it is It may still be desirable when the doping of the vias is different from the doping of the main body doping, for example, to achieve different conductivity, dopant concentration or dopant type. The fabrication of vias is doped in the bulk (steps are performed, then - the E-M steps are necessary to achieve the sidewalls of the holes - satisfactory conductivity 〇 according to current state of the art technology) After making the via hole itself, the fabrication of the via hole itself is performed, for example, by laser drilling. On the contrary, according to the present invention, the additional replacement step and the via hole for the via hole are made (IV) 157945.doc 201214744 Opening and drilling) are carried out at the same time. It should be noted that the simultaneous production and doping are independent of the actual time of fabrication of the through-holes. This is why this step is not in the above sequence of procedures (4) to the accompanying exhibition. The combined drilling/doping step can be carried out not only after step (4) mentioned above, but also before or even during it. Therefore, even if the emitter doping by the diffusion step has not been carried out, the implementation is carried out. The combined drilling/doping step can also be advantageous because the walls of the vias can achieve a better (higher) conductivity than the remainder of the board (because the vias are doped by two people, while the substrate The remaining portion is only doped once.) Furthermore, different dopants and/or doping times can be used for each of the two t-hybrids. Additionally, an additional doping step can be performed simultaneously with the bulk doping step, This makes it possible, for example, to achieve different doping results in and through the vias. For the combined fabrication/doping of vias, it is preferred to use liquid jet-guided laser processing techniques, in particular LCP (laser chemical processing) and LIp. (Photolithography), which will be described in more detail later. According to a preferred embodiment of the present invention, the fabrication and doping of vias are performed by laser chemical processing (LCP), and the liquid droplets of Lcp are used to guide laser processing - a special form - using dopants Liquid rather than water, or it is performed by dry laser processing. Here, both techniques use a liquid containing a source of dopant. An LCp, also referred to as and described as "liquid jet guided laser processing," uses a laser beam that is coupled into a liquid jet and directed by the liquid jet. The laser provides primary use for melting and ablating the laser. The energy that is directed to the surface to which it is directed. Lasers can also deliver the energy required for a chemical reaction, or increase the chemical reaction by 157945.doc 201214744. The liquid itself contains components that chemically interact between the laser (four) and the surface to which the illumination is directed. Typical liquids: water (oxidation characteristics on certain materials), or liquids containing a dopant, such that, for example, the through holes can be drilled and doped at the same time. Because the laser interacts differently with different materials, such as when reaching a previously created metal layer (e.g., a through-hole rear side contact), stopping the drilling system is not a problem. However, depending on the particular subsequent procedural steps, the vias may even be drilled through the substrate and contacts and (iv) provided to the electrical contacts positioned at the front side of the emitter. - Instead of the "dry" technique, a laser beam is also used which is not guided by a liquid jet but directly strikes the surface to be treated. However, in order to achieve a chemical reaction or modification of the treated surface, a thin liquid layer containing one of the necessary chemical components (such as dopants) is applied to the surface during or prior to the laser treatment, thus the actual laser Drying is achieved prior to irradiation. The dish acid (H3p〇4) can advantageously be used for this liquid. The goal of both techniques is to fabricate through-vias and simultaneously dope the vias to allow a passivation layer opening that may be present for further processing involving metallization' and/or to simultaneously modify the thus exposed surface. However, this does not imply that these techniques are limited to this use during the manufacture of solar cells. In accordance with another embodiment of the present invention, the fabrication of the vias is performed after the formation of a layer of nitride and/or a layer of dioxide. This layer is usually required for both passivation and anti-reflection purposes (see also step (e) above). According to current state of the art technology, vias are inserted into the substrate at very early stages, i.e., prior to step (b) mentioned above. As a result, all subsequent steps 157945.doc •10-201214744 are carried out on the through-substrate, bringing the above-mentioned „^^ phase (4). According to the present invention, the procedure for through-holes can be performed in the -day segment That is, it is performed after the contact. Therefore, most, if not all, of the steps (4) to (8) of the above-mentioned k and the above steps are performed on the standard (ie, non-penetrating) substrate. The adaptation of the program steps is no longer applicable, or small-scale application. The breakage rate of the generally fragile substrate is significantly reduced. Another advantage is that the use of a so-called selective emitter can now be easily achieved. The regions reserved for metallized contacts (eg, to the fingers) are highly doped, thus providing - low sheet resistance (eg, 20 ohms/square) and - good metal ♦ contact, and representing the illumination of the solar cell The remaining area of the surface is less doped, thus providing a higher sheet resistance (e.g., 12 ohms/square) and lower recombination. According to the present invention, the selective emitter is produced prior to fabrication of the aperture, making it possible to Easy to make Solar cells, especially MVT cells with through-holes and selective emitters. This in turn increases cell efficiency. In the case where front-side fingers are present as needed, for these front-side fingers, the above mentioned implementation is The Lcp treatment and doping on the holes is preferably used in combination with local doping for the front side opening of a purification layer. According to a further preferred embodiment, the metallization of the vias is by photo-plating (UP) or no electricity. Electroplating is carried out. As mentioned above for 2Lcp treatment and doping, this metallization method is advantageously used for the presence of front side fingers as needed. As mentioned above, the conductivity of screen printing pastes commonly used in solar cell manufacturing The rate and the achievable geometry are insufficient. A better conductivity can be achieved by electroplating techniques that contribute to a pure metallization layer of 157945.doc 201214744. Furthermore, subsequent firing is no longer used. In general, however, all possible types of electroplating techniques can be advantageously used in the present invention, especially preferred photolithographic techniques or electroless plating. In the case of a solar cell, charge carriers are generated and charge carriers can conduct current from one side to the other. One side is connected to a first electrode and a second plated electrode is used, thus causing contact with the electrolyte Electroplating of the surface of the battery. The same applies to battery vias that have been drilled and doped with LCP, while a masked or non-conductive region of a solar cell, such as a passivation region, remains unplated. The metal stack is, for example, Ni-Ag, Ni-Cu-Sn or Ni-Cu-Ag. Electroless plating does not use an external current, and can also be used to electroplate or strengthen the conductive structure of a solar cell. The highly viscous phase, the metallized structure is not only the conductivity but also the controllability of the quality and geometry is far better than the use of the paste. The use of screen printing cannot be completely omitted in the process, and the number of screen printing steps is significantly reduced. For example, for a battery that was necessary for the previous four screen printing steps, ie, (1) for the rear side emitter bus bar and hole contact, (2) for the base pad '(3) for the rear side aluminum region' And (4) the first and fourth steps may be omitted for the front side emitter contact', since a higher conductivity 'not only results in a better product quality' but also results in the saving of a portion of the silver-containing and therefore expensive paste. . In addition, the necessary flipping of the battery by the two-sided screen printing procedure can be omitted, resulting in further simplification of the procedure and reduced risk of breakage. Furthermore, if a subsequent firing procedure is performed, ^ 〇 I57945.doc 12 201214744 is designed to "optimize the impurity * less requirements" resulting in a step-by-step reduction of the second: τ battery, electric clock pass The high conductivity of the holes results in a very advantageous reduction of the necessary pore distribution density on the surface of the cell. According to a further embodiment of the invention, at least the side to be performed on the back side, the isolation step "is guided by the liquid flow guide" Or other (eg processing proceeds. % edge isolation is necessary to prevent cross-flow between conductive regions of different polarity (such as the anode and cathode of the battery), ie the shunt between the front side emitter and the back side contact. The emitter described in the above step (4) is generated on the entire surface of the battery. The conductive layer covers not only the front side and the back side but also the side edges. Therefore, edge isolation is necessary. (4) It is preferably used. The LCP or dry-tray processing performs other necessary isolation steps, such as an edge isolation step on the front side, or a contact isolation step between the rear side emitter and the base region. Typical liquid for this procedure step Is water (Η") or an oxidizing liquid. According to another embodiment, the edge isolation is performed using wet chemical etching instead of LCP, and the emitter strip remains on the back side, on which the emitter bus bar metal is subsequently applied The strip regions may be masked accordingly such that only regions outside the strip are opened and the strip regions are still covered by the emitter diffusion. According to a further embodiment, the metallized vias are used directly for the mold The solder pads of the emitter contacts of the group are fabricated. No additional emitter bus bar metallization is performed on the back side. This means that there are no emitter fingers and/or emitter bus bars on the back side but metal The emitter vias are soldered directly to the interconnecting tabs. 157945.doc 】3· 201214744 The rear foil of the module can be soldered with bumps to align the cells to the vias. Then, on the back of the module The solder bumps are soldered to the metallized vias and achieve cell interconnection. The advantage here is that less material and manufacturing steps must be performed on the back side of the cell, thereby reducing the cost of the cell. Pad and / or corresponding area can be Solder covering, which liquefies during heating and solidifies at the location of the connection when cooled. According to a further embodiment 'one of the emitters controls etch back by doping by diffusion as described above for step (C) to produce The step of the emitter is performed to increase the sheet resistance. This optional step also helps to improve the blue sensitivity and reduce the surface recombination effect because a highly doped surface region (dead layer) is removed. Thus, etch back enhances cell efficiency. The touchback can be performed by, for example, a hydrofluoric acid/acid (HF_HN〇3) solution, or by a reactive ion etching (RIE) technique. According to another embodiment, The side polishing is performed after a side passivation is usually present. This step is advantageously performed directly after the optional etch back step, or if the etch back is not performed, after the diffusion step. Polishing results in a smoother surface and helps reduce recombination losses. According to yet another example, the passivation of the rear side of the battery is performed additionally or separately. This is done additionally or in place of step (e) in addition to step (e) mentioned above, which step (e) has only referred to the front side so far. However, if the front side passivation is also performed, it is advantageous to directly perform the back side passivation step before or after step (e). It is also possible to perform two steps at a time, i.e., passivate the entire substrate, for example, by dipping it in a suitable solution, or by using pEcvD (plasma enhanced chemical vapor deposition). Possible layer materials can be, for example, eight 12〇3, 157945.doc -14- 201214744
Al2〇3加上由 PECVD沈積之一層、Al2〇3+SiNx、Ai2〇3+si〇x、Al2〇3 plus one layer deposited by PECVD, Al2〇3+SiNx, Ai2〇3+si〇x,
Si〇x、Si〇2、SiNj Si〇2 + SiNx。此外，許多堆疊材料的X 一 序列係可行的。 根據又另一實施例，後側鈍化層之開口藉由LCp進行。 因為該程序較佳地使用於如上文所描述之邊緣隔離，兩個 步驟可有利地由相同的技術執行.相應的液體係水或含有 摻雜劑之液體。在此步驟之後，進行後側金屬化。Lcp代 替乾式雷射f汗1 口的ϋ優點為避免在燒钱期間可能以 其他方式產生的灰塵。 總而言之，LCP不僅對於邊緣隔離係較佳的，而且對於 為製造匯流條而在稍後經金屬化（即，網印或電鍍）的區域 之開口亦係較佳的。 相應地，隨後的後側金屬化藉由網印或LIp進行。在 此 酼後」指先前實行之藉由濕式蝕刻或LCP使鈍化層 開口的步驟。 因為已在上文中詳細描述所有程序，不再提供其進一步 之解釋。 根據一較佳實施例，後側金屬化藉由網印進行，且之後 穿透燒製鈍化層而無須該鈍化層之分離開口。換句話說， 該鈍化層之開口藉由穿透燒製本身而進行。如上文所提 及’網印膏之相應成分的溫度觸發之化學反應冑致由該膏 覆蓋之處該鈍化層被蝕刻掉，在未進一步需要執行一開口 步驟之情況下導致一電接觸。 根據本發明之另—實施例，在惰性或還原性氛圍中進行 157945.doc 15 201214744 最，，·； /m度處理作為一實例，較佳地使用在〗〇〇°C與5〇〇。〇 之間之皿度及自〇·5分鐘至30分鐘之處理時間。該氛圍有 利地由純氮氣（N2)組成，或由成形氣體（諸如氮氣中作。的 氫氣）組成。 本發明進一步係關於具有燒製之接觸件及具有貫穿電池 之通孔的一金屬穿透式背電極（MWT)或射極穿透式背電極 (EWT)太陽能電池’其中該電池特徵為在該等通孔之至少 諸壁上的一無空隙、純且平滑的金屬化層。 特疋《之本叙明係關於由上文定義之一方法獲得及/ 或可獲得的此一電池。 因為根據當前最先進技術製造的一太陽能電池係使用網 印及相應的膏而生產，此膏導致不均句填充的導電體積。 一方面，例如對於該膏之適當粘性所必需之額外成分並不 貢獻於（期望之）導電率。另一方面，在該膏的固化期間， 此等添加劑可收縮或甚至消失，從而留下空隙。此不僅減 小導電率，且亦可為減小機械穩定性的一起源。此外，此 等固化膏之表面在微觀標度上通常不平坦及平滑，而β凹 凸不平及充滿裂縫《相反地，當檢驗例如一通孔或—指狀 部（若存在）之一截面時，根據本發明製造（即，藉由使用 LCP及UP以及在如上文所描述之—較後階段插入至基板 中的通孔）的一太陽能電池顯示平滑及平坦之金屬化表面 以及實質上無空隙之體積。此外，因為在金屬化期間沒有 添加劑沈積於層上或層内’所得材料由純金屬組成，亦提 供一較好的導電率。 157945.doc -16 - 201214744 如_明’本❹解決此項技術t已知之許多問題。特 疋，之，當應經摻雜之通孔的製作係在藉由擴散步驟的一 主體摻雜之後、同時或之前進行時，根據本發明之方法減 少程序步驟的數目。其進―步減小將_製程從不具有通孔 之基板調適至具有通孔之基板的努力，因為根據一：施 例’孔的製作在製造電池期間的—極後階段進行。該程序 達成可能存在之狹窄指狀部之幾何形狀的_更好可控性， 此係因為其允許用LIP替代一些通用網印步驟。复亦改， 尤其前側指狀部及/或金屬穿透式背電極通孔兩者的導電又 率。若在太陽能電池製造之處理序列將近結束時實行通孔 :;作其則可明顯減少程序步驟之數目，且尤其是對於已 貝穿之基板的程序步驟之數目。 157945.doc 17-Si〇x, Si〇2, SiNj Si〇2 + SiNx. In addition, many X-sequences of stacked materials are possible. According to yet another embodiment, the opening of the backside passivation layer is performed by LCp. Since the procedure is preferably used for edge isolation as described above, the two steps can advantageously be performed by the same technique. The corresponding liquid system water or liquid containing the dopant. After this step, backside metallization is performed. The advantage of Lcp for dry laser f 1 1 port is to avoid dust that may otherwise be generated during the burning process. In summary, LCP is preferred not only for edge isolation but also for openings that are later metallized (i.e., screen printed or plated) for the fabrication of bus bars. Accordingly, subsequent backside metallization is performed by screen printing or LIp. "After this" refers to the previously performed step of opening the passivation layer by wet etching or LCP. Since all the procedures have been described in detail above, no further explanation is provided. According to a preferred embodiment, the backside metallization is performed by screen printing and then the fired passivation layer is penetrated without the separate opening of the passivation layer. In other words, the opening of the passivation layer is performed by penetrating the firing itself. As discussed above, the temperature-triggered chemical reaction of the corresponding component of the screen printing paste causes the passivation layer to be etched away from the paste, resulting in an electrical contact without further need to perform an opening step. According to another embodiment of the present invention, 157945.doc 15 201214744 is used in an inert or reducing atmosphere as an example, preferably used at 〇〇 ° C and 5 〇〇. Between the 〇 and the processing time of 5 minutes to 30 minutes. The atmosphere is advantageously composed of pure nitrogen (N2) or a forming gas such as hydrogen in nitrogen. The invention further relates to a metal-transmissive back electrode (MWT) or emitter-transmissive back electrode (EWT) solar cell having a fired contact and having a through hole through the battery, wherein the battery is characterized in that A void-free, pure and smooth metallization layer on at least the walls of the via. The present specification is directed to such a battery obtained and/or available by one of the methods defined above. Since a solar cell manufactured according to the current state of the art technology is produced using screen printing and a corresponding paste, this paste results in a conductive volume filled with unevenness. On the one hand, the additional ingredients necessary for the proper viscosity of the paste, for example, do not contribute to the (desired) conductivity. On the other hand, during the curing of the paste, these additives may shrink or even disappear, leaving a void. This not only reduces the electrical conductivity, but can also be a source of reduced mechanical stability. In addition, the surface of such curing pastes is generally not flat and smooth on the microscopic scale, while the β is uneven and full of cracks. Conversely, when examining a cross section such as a through hole or a finger (if present), A solar cell fabricated in accordance with the present invention (i.e., by using LCP and UP and through-holes inserted into the substrate at a later stage as described above) exhibits a smooth and flat metallized surface and a substantially void-free volume . In addition, because no additives are deposited on or in the layer during metallization, the resulting material is composed of pure metal, which also provides a better conductivity. 157945.doc -16 - 201214744 Many problems are known to solve this technique. In particular, the number of procedural steps is reduced in accordance with the method of the present invention when the fabrication of the via which is to be doped is performed after, simultaneously with or prior to doping by a bulk of the diffusion step. This further reduces the effort to adapt the process from a substrate having no vias to a substrate having vias, since the fabrication of the holes according to one example is performed at the post-stage during the manufacture of the cell. This procedure achieves a better controllability of the geometry of the narrow fingers that may exist because it allows for some common screen printing steps to be replaced with LIP. The conductivity is also changed, especially for the front side fingers and/or the metal penetrating back electrode through holes. The vias are implemented at the end of the processing sequence for solar cell fabrication; as such, the number of program steps can be significantly reduced, and in particular the number of program steps for the substrate that has been worn. 157945.doc 17-