201145547 六、發明說明： 【發明所屬之技術領域】 本發明係有關結晶系太陽能電池，特別是使用矽基板 之太陽能電池的受光面電極之形成方法。 【先前技術】 圖5 ( a )係顯示以往之結晶系太陽能電池的單元構造 槪略圖，圖5 ( b )係顯示以往之結晶系太陽能電池的單元 構造平面圖。 如圖5 ( a ) ( b )所示，以往之結晶系太陽能電池的 單元1〇1係於形成有紋理102之矽基板103的表側面（射入 光：1 〇〇側的面），依序形成n +型半導體層104，反射防止膜 1〇ί;，更且對於反射防止膜105上，延伸成直線狀之受光面 電極106 (母線桿電極l〇6a及指狀電極106b )則呈與η+型 半導體層1 04連接地加以形成。 另一方面，對於矽基板1 03的背側面，係依序形成有 Ρ +型半導體層107，背面電極108。 以往，結晶系太陽能電池的受光面電極1 06係由使用 銀11糊之網版印刷而形成。 但在以往技術中，爲了降低受光面電極1 06的阻抗値 ’必須將指狀電極1 06b的線寬加大爲1 00 m程度，將母線 桿電極106a的線寬加大爲2mm程度，其結果，在以往技術 中，有著開口率爲低的93 %程度之課題。 另外，在網版印刷中，亦有網版與太陽能電池的表面 -5- 201145547 接觸之故而基板產生破損，以及由不銹鋼所成之網目接觸 於石夕層而造成損傷之問題。 然而，做爲有關本發明之先前技術，係有如以下所示 之構成。 以往技術文獻 [專利文獻] [專利文獻1]日本特開昭49- 1 1 48 8 7號公報 [專利文獻2]日本特開2006-295197號公報 [專利文獻3 ]日本特開2 0 0 1 - 1 1 8 4 2 5號公報 【發明內容】 [發明欲解決之課題] 本發明係爲了解決如以往技術之課題所作爲之構成， 作爲其目的係提供可提升開口率之太陽能電池單元之受光 面電極形成技術。 另外，本發明之其他目的係提供未對於矽層造成損傷 之太陽能電池單元之受光面電極形成技術。 [爲解決課題之手段] 爲了解決上述課題所作爲之本發明係具備於光入射側 之表面側具有第1導電型層，且於背面側具有第2導電型層 之半導體基板，於前述半導體基板之第1導電型層上，設 置有反射防止膜和受光面電極之同時，於前述半導體基板 -6- 201145547 之第2導電型層上，設置連接用背面電極，前述受光面電 極則經由導體所成之打線所構成之結晶系太陽能電池單元 〇 在本發明中，對於前述打線則由金，銀，銅，鋁，细 ，或此等合金所成之情況亦有效果。 在本發明中，對於前述受光面電極則藉由含有玻璃料 之導電性燒結體所成之連接膜，電性連接於前述半導體基 板之第1導電型層之情況亦有效果。 在本發明中，對於前述受光面電極則具有設置於前述 半導體基板之第1導電型層上的第1之受光面電極，和設置 於該第1之受光面電極上的第2之受光面電極，前述第1之 受光面電極則藉由前述導電性燒結體所成之第1之連接膜 ，電性連接於前述半導體基板之前述第1導電型層之同時 ，前述第2之受光面電極則藉由前述導電性燒結體所成之 第2之連接膜，電性連接於前述第1之受光面電極之情況亦 有效果。 另一方面，本發明係準備於光入射側之表面側具有第 1導電型層，且在於背面側具有第2導電型層之半導體基板 的第1導電型層上，設置反射防止膜之太陽能電池用基板 ，經由使用含有玻璃料之導電性電糊，燒結該導電性電糊 之時，將經由導體所成之打線加以構成之受光面電極，固 定於前述太陽能電池用基板上之同時’具有將該受光面電 極，對於前述半導體基板之第1導電型層而言加以電性連 接之工程的結晶系太陽能電池單元之製造方法。 201145547 在本發明中，對於具有前述受光面電極具備第1及第2 之受光面電極，於前述反射防止膜上’塗佈乾燥前述導電 性電糊而形成第1之連接膜的工程，和於前述第1之連接膜 上配置前述第1之受光面電極的工程’和燒結前述第1之連 接膜的工程，和於前述第1之受光面電極上，塗佈乾燥前 述導電性電糊而形成第2之連接膜的工程，和燒結前述第2 之連接膜的工程之情況亦有效果。 在本發明中，對於具有準備於前述打線塗佈乾燥前述 導電性電糊而形成連接膜的受光面電極，將前述受光面電 極配置於前述太陽能電池用基板上的工程，和燒結前述受 光面電極之連接膜的工程之情況亦有效果。 在本發明中，對於塗佈前述導電性電糊之工程則經由 分注法或噴墨法之構成的情況亦有效果。 本發明之情況，受光面電極則經由導體所成之打線而 加以構成，與經由以往技術之網版印刷的受光面電極做比 較，於做成具有同等配線阻抗之電極的情況，可將受光面 電極的寬度做成非常小》其結果，可將在以往技術中爲 93%程度之太陽能電池單元之開口率，大幅度提升爲99% 程度。 另外，本發明之情況，從經由導電性電糊之塗佈及燒 結而將受光面電極固定於太陽能電池用基板上之情況，導 電性電糊之塗佈手段則未接觸於太陽能電池用基板，未有 如以往之網版印刷之情況，基板產生破裂，以及對於矽層 造成損傷。 -8 - 201145547 更且’在本發明中，將打線所成之受光面電極，藉由 導電性電糊而配置於反射防止膜上，在此狀態，從燒結含 有玻璃料之導電性電糊所成之第1之連接膜情況，經由根 據反射防止膜與第1之連接膜的反應之燒成貫通，藉由所 燒結之連接膜而可確實地電性連接受光面電極與半導體基 板的第1導電型層。 [發明效果] 如根據本發明，可大幅地提升結晶系太陽能電池單元 之開口率。 【實施方式】 以下，參照圖面詳細說明本發明之理想實施形態。 圖1 ( a ) ~ ( d )係顯示本實施形態之結晶系太陽能電 池單元之製造工程的剖面圖（其1 )、圖2 ( a ) ~ ( c )係 顯示同實施形態之結晶系太陽能電池單元之製造工程的剖 面圖（其2 )。另外，圖3係同實施形態之結晶系太陽能電 池II元之平面圖。 如圖1 ( a )所示，在本實施形態中，首先，準備於形 成有紋理（未圖示）之矽基板（半導體基板）1 〇的表側面 (允射入側的面），依序形成有第1導電型層之n +型半導 體層1 1，反射防止膜1 2，於其背側面，依序形成有第2導 電型層之P +型半導體層13，背面電極層14之太陽能電池用 基板1。 -9 - 201145547 本發明之情況，反射防止膜1 2的材料係並無特別加以 限定，但從確保與後述之燒結時的導電性電糊之反應性的 觀點，係可最佳使用氮化矽（SiN )，氧化矽（Si02 )， 氧化鈦（Ti〇2)。 另外，反射防止膜1 2的厚度係無特別加以限定，但從 降低反射率的觀點’係作爲100〜500nm爲佳》 然而，作爲背面電極層1 4之材料係例如最佳可使用銀 (Ag)電糊。 接著，如圖1 (b)所示，於反射防止膜12的表面，隔 開特定的間隔，塗佈形成由後述之導電性電糊所成之複數 的第1之連接膜（連接膜）15，之後，使此等第1之連接膜 15乾燥。 在此，塗佈形成第1之連接膜1 5之位置係對應於設置 後述之指狀電極（第1之受光面電極）2 1之位置的位置， 例如，塗佈形成爲與指狀電極2 1的長度同等長度即可。 本發明之情況，第1之連接膜1 5的塗佈方法係無特別 加以限定，但從精確度佳地形成第〗之連接膜1 5之觀點， 採用經由分注器的方法，或經由噴墨的方法爲佳。 另外，第1之連接膜1 5的寬度係無特別加以限定，但 從更提升太陽能電池單元之開口率的觀點，較指狀電極2 1 的寬度縮小第1之連接膜15之寬度爲佳。 具體而言，將第1之連接膜15的寬度設定爲5〜15/z mm 佳。 另一方面，形成第1之連接膜1 5的厚度係無特別加以 -10- 201145547 限定，但從確保充分的黏接強度，且更提升太陽能電池單 元之開口率的觀點，作爲較反射防止膜12爲厚爲佳。 具體而言，將第1之連接膜15的厚度設定爲5 0 0〜 lOOOOnm爲佳。 作爲使用於第1之連接膜1 5的導電性電糊，例如最佳 可使用記載於日本特開2006-2 95197號公報之導電性電糊 〇 在本發明所使用導電性電糊係含有導電性金屬，和無 .機結合劑，有機媒介。以下，對於各成分加以說明。 作爲在使用於本發明之導電性電糊可含有之導電性金 屬，可舉出銀粒子，且銀粒子最佳。其銀粒子係理想爲薄 片形態或粉末形態之構成。 本發明之情況，導電性電糊的銀粒子的粒徑係無特別 加以限定，但考慮燒結特性的影響（具有大粒徑之銀粒子 係以較具有小粒徑之銀粒子的速度爲慢的速度進行燒結） 及塗佈之容易度時，銀粒子的平均粒徑係作爲3.0〜1 5.0 # m爲佳，而更佳爲5.0~1 1.0 // m。 銀粒子的粒徑較3.0 // m爲小的情況，銀導電性電糊係 顯六急遽燒結之特性，有著因與鋁電糊的燒結速度的不匹 配引起，在此等2個電極間產生龜裂的傾向。 另一方面，銀粒子的粒徑較1 5.0 // m爲大的情況，導 電性則下降，及電極薄膜的強度則減少。此理由係因未充 分進行燒結。 作爲含於導電性電糊的銀粒子係具有銀爲高純度（ -11 - 201145547 99%以上）爲佳，但對應於電極圖案的電性要求，亦可另 外使用未達99%之純度的物質》 在導電性電糊最佳之導電性金屬係如上述爲銀粒子， 但同樣地可使用銀以外之導電性金屬。例如，如銅（Cu ) 、金（Au)、鈀（Pd)及白金（Pt)之金屬爲有用。加上 ，前述金屬之合金或混合物亦在本發明中同樣爲有用。例 如’可使用 Cu— Au，Ag— Pd’ Pt— Au 等。 在導電性電糊之導電性金屬的含有量係只要爲可達成 本發明之目的量，並無特別加以限定，但從導電性確保的 觀點，係例如對於銀粒子，將導電性電糊的重量作爲基準 ，以40〜93質量％的量而含有爲佳。 然而，以提升所期望的特性之目的，對於導電性電糊 而言，亦可添加銘（A1 )。 使用於本發明之導電性電糊係含有無機結合劑。 作爲如此之無機結合劑，係可最佳使用具有450〜5 50 °C之軟化點的玻璃料（微粒子）。 如此之玻璃料係以6 0 0〜8 0 0 °C燒固導電性電糊，適當 地進行燒結及潤濕，及對於矽基板1 0而言可適當地黏接。 當玻璃料的軟化點較4 5 0 °C爲低時，燒結則成爲過剩 ，有著無法充分得到本發明之效果情況。 另一方面’當玻璃料的軟化點較550 °C爲高時，有著 未發揮充分的黏接強度，且無法促進銀的液相燒結之情況 。其理由係因於燒結中未產生有充分的熔融流動情況引起 -12- 201145547 在本說明書中，作爲軟化點，適用經由ASTM (美國 材料試驗協會：American Society for Testing and Με.terials ) C338-57 之纖維伸長法（fiber elongation m e t h o d )所規定之構成。 作爲含有於導電性電糊之玻璃料係無特別加以限定， 但當考慮軟化點範圍及玻璃可熔性之雙方條件時，例如可 最'圭使用矽酸玻璃，硼矽酸玻璃等。 然而’亦可使用未含有如硼矽酸鋅的鉛之玻璃。 作爲無機結合劑之玻璃料的含有量係只要爲可達成本 發明之目的量’並無特別加以限定，但將導電性電糊的總 重量作爲基準，做成2.0-10.0質量％爲佳，而更佳爲3 〇〜 6.0質量％。 當玻璃料的含有量較2.0質量％爲少時，有著黏接強度 成爲不充分之情況’另一方面，當玻璃料的量較丨〇. 〇質量 %爲多時’例如有著作爲後加工而進行之圖案附加工程則 經曰玻璃之浮游（glass float ing )等而阻害之情況。 使用於本發明之導電性電糊係含有有機媒介。 作爲含於導電性電糊之有機媒介，係可使用非活性液 體= 作爲如此之非活性液體，作爲有機液體，例如可舉出 醇類；醇的酯類（如醋酸鹽或丙酸酯之構成）：澱粉（如 松泊及萜品醇之構成）：樹脂（聚甲基丙烯酸酯等）或乙 基纖維素之松油溶液或乙二醇乙醚醋酸之溶液，或如乙基 纖維素之萜品醇溶液之各種溶液。 -13- 201145547 在本發明中，作爲有機媒介，可最佳使用乙基纖維素 之蔽品醇溶液（乙基纖維素含有量=5〜50質量％)。 有機媒介之理想含有量係將導電性電糊之總重量作爲 基準，爲5〜50質量％。 對於使用於本發明之導電性電糊，係可添加增黏劑或 安定劑，或一般的添加劑。 在使用添加劑時，可添加黏接賦予劑（黏接劑），安 定劑等，或者作爲其他一般的添加劑而亦可添加分散劑， 黏度調整劑等。' 添加劑的量係依據最終所得到之導電性電糊的特性而 加以決定，而有關之製造者可適當做決定。然而，亦可使 用數種的添加劑。 使用於本發明之導電性電糊係具有特定範圍內之黏度 爲佳。 對於導電性電糊而言，爲了賦予適當的黏度，可由添 加上述之黏接賦予劑（增黏劑）而達成。 使用於本發明之導電性電糊係可經由公知3支攪拌機 混合上述各成分而製造。 使用於本發明之導電性電糊的黏度係無特別加以限定 ，但使用黏度計（Brookfield ) HBT黏度計及使用# 14軸 心之功用量杯，在旋轉數1 Orpm及溫度25 °C加以測定時’ 呈成爲50〜300Pa · S地進行調整爲佳。 在本實施形態中，將以上說明之導電性電糊所成之第 1之連接膜1 5，複數塗佈形成於反射防止膜1 2上之後’使 -14 - 201145547 此等第1之連接膜1 5乾燥。此情況，理想之乾燥溫度係1 8〇 t：以下。 更且，如圖1 (c)所示，於各第1之連接膜丨5上，位 置調整打線所成之指狀電極21而配置（載置）。 本發明之情況’構成指狀電極2 1之打線的材料係無特 別加以限定，但可最佳使用金（Au )，銀（Ag )，銅（ Cu)鋁（A1)，鈀（Pd)，或此等合金所成之構成。 其中，從提升導電性的觀點，使用銀（Ag )爲佳。 然而構成指狀電極2 1之打線的剖面形狀係正圓形狀 ，從提升開口率之觀點，其直徑愈小程度爲佳。 但，考慮作爲電極所要求之強度或配線阻抗的大小時 ，直徑作爲10〜100 μ m爲佳。 更且，將配置指狀電極2 1之太陽能電池用基板1，在 空氣中，歷經溫度600〜800°C、2〜15分鐘進行加熱而燒結 。此情況，加壓指狀電極2 1亦可。 由此，含於第1之連接膜15之導電性電糊的玻璃料與 反射防止膜1 2之物質產生反應，反射防止膜1 2則熔解，如 圖1 ( d)所示，燒結之第1之連接膜（以下稱作「第1之燒 結連接膜」）1 6則埋沒（燒成貫通）於反射防止膜1 2中。 更且，經由上述燒結工程，各指狀電極2 1則對於第1 之燒結連接膜1 6而言加以固定。 其結果，第1之燒結連接膜16與n+型半導體層11接觸 而此等加以電性連接之故，藉由連接膜之第1之燒結連接 膜1 6而電性連接指狀電極2 1與n +型半導體層1 1 » -15- 201145547 在此狀態中，第1之燒結連接膜1 6的寬度係較各指狀 電極2 1之寬度爲小。 然而，經由上述之燒結工程，亦燒成表面電極層1 4之 銀電糊，形成燒結背面電極層1 4a。 之後，如圖2 ( a )所示，將上述導電性電糊所成之第 2之連接膜1 7，塗佈形成於各指狀電極2 1上，之後將此等 進行乾燥。 本發明之情況，第2之連接膜17的塗佈方法係無特別 加以限定，但從精確度佳地形成第2之連接膜1 7之觀點， 採用經由分注器的方法，或經由噴墨的方法爲佳。 另外，第2之連接膜1 7的的寬度係無特別加以限定， 但從更提升太陽能電池單元之開口率之觀點，較後述之母 線桿電極22的寬度減少第2之連接膜1 7的長度（對於母線 桿電極22之延伸方向而言垂直交叉之方向的長度）爲佳。 具體而言，將第2之連接膜17的寬度設定爲5-15;/ m爲 佳。 然而，第2之連接膜17的理想之乾燥溫度係I80°C以下 〇 另一方面，第1之連接膜15的厚度係設定爲5〇〇~ lOOOOnm爲佳◊ 更且，如圖2(b)所示，於各第2之連接膜17上，位 置調整打線所成之母線桿電極22而配置（載置）。 本發明之情況，構成母線桿電極2 2之打線的材料係無 特別加以限定，但可最佳使用金（Au )，銀（Ag )，銅 -16- 201145547 (Cu )鋁（A1 )，鈀（Pd )，或此等合金所成之構成。 其中’從提升導電性的觀點，使用銀（Ag )爲佳。 然而’構成母線桿電極22之打線的剖面形狀係正圓形 狀’從提升太陽能電池單元的開口率之觀點，其直徑愈小 程度爲佳。 但’考慮作爲電極所要求之強度或配線阻抗的大小時 ’直徑作爲120〜500 # m爲以下佳。 更且，將配置母線桿電極22之太陽能電池用基板1， 在空氣中，歷經溫度6 0 0〜8 0 0 °C、2〜1 5分鐘進行加熱而燒 結。此情況，加壓母線桿電極22亦可。 由此，燒結第2之連接膜1 7，各指狀電極2 1則對於所 燒結之第2之連接膜（以下稱作「第2之燒結連接膜」）18 而言加以固定之同時，各母線桿電極22則對於第2之燒結 連接膜1 8而言加以固定。 其結果，如圖2 ( c )及圖3所示，藉由連接膜之第2之 燒結連接膜18而電性連接母線桿電極22與指狀電極21，得 到具有對於矽基板10而言加以電性連接之第1及第2之受光 面電極之結晶系太陽能電池單元3 0。 如以上所述，在本實施形態中，受光面電極之指狀電 極2 1及母線桿電極22則經由導體所成之打線所構成，與經 由以往技術之網版印刷的受光面電極做比較，於做成具有 同等之配線阻抗的電極之情況，可非常縮小受光面電極的 寬度。其結果，可大幅地提升結晶系太陽能電池單元之開 □率。 -17- 201145547 另外，在本實施形態中，從經由導電性電糊之塗佈乾 燥及燒結’將指狀電極21及母線桿電極22固定於太陽能電 池用基板1上之情況，導電性電糊之塗佈手段未接觸於太 陽能電池用基板1，而未有如以往之網版印刷之情況’基 板產生破裂，對於矽層造成損傷的情況。 另外，在本實施形態中’將打線所成之指狀電極2 1 ’ 藉由導電性電糊而配置於反射防止膜1 2上，在其狀態’從 燒結含有玻璃料之導電性電糊所成之第1之連接膜1 5之情 況，經由根據反射防止膜12與第1之連接膜15之反應的燒 成貫通，藉由第1之燒結連接膜16而可確實地電性連接指 狀電極21與半導體基板10之n +型半導體層11。 圖4 ( a )〜（c )係顯示本發明之其他實施形態，以下 ，對於與上述實施形態共通的部份係附上同一的符號，省 略其詳細的說明。 在本實施形態中，首先，如參照圖1 ( a )〜（d )加以 說明地，經由進行導電性電糊之塗佈，乾燥及燒結之時， 在太陽能電池用基板1上，藉由第1之燒結連接膜16而電性 連接指狀電極21與11 +型半導體層11。 之後，如圖4 ( a )所示，於母線桿電極22的表面，拉 開特定間隔，塗佈形成上述導電性電糊所成之複數的第2 之連接膜1 7，之後使此等乾燥。 在此，塗佈形成母線桿電極22表面之第2之連接膜17 的位置係作爲與設置於太陽能電池用基板1上之指狀電極 2 1的連接部分爲佳。 -18- 201145547 本發明之情況’第2之連接膜1 7的塗佈方法係無特別 加以限定，但從精確度佳地形成第2之連接膜1 7於母線桿 電極22表面之觀點，採用經由分注器的方法，或經由噴墨 的方法爲佳。 另外，第2之連接膜1 7的寬度係無特別加以限定’但 從更提升太陽能電池單元之開口率之觀點’較母線桿電極 22的寬度減少第2之連接膜17的長度（對於母線桿電極22 之延伸方向而言垂直交叉之方向的長度）爲佳。 另一方面，第2之連接膜1 7的厚度係無特別加以限定 ，但從確保充分的黏接強度，且更提升太陽能電池單元之 開]率的觀點，設定爲500~1 0000nm爲佳。 並且，母線桿電極22之第2之連接膜17，和太陽能電 池用基板1之指狀電極2 1之位置則呈一致地進行位置調整 ，如圖4 ( b )所示，太陽能電池用基板1上之指狀電極2 1 與第2之連接膜17則呈接觸地配置（載置）母線桿電極22 〇 之後，將其太陽能電池用基板1，在空氣中，歷經溫 度¢00〜800 °c、2〜15分鐘進行加熱而燒結。此情況’加壓 母綠桿電極22亦可。 由此，與上述實施形態同樣地，燒結第2之連接膜1 7 ，如圖4 ( c )所示，各指狀電極2 1則對於第2之燒結連接 膜18而言加以固定之同時，各母線桿電極22則對於第2之 燒結連接膜18而言加以固定。 其結果，與上述實施形態同樣，得到藉由第2之燒結 -19- 201145547 連接膜1 8而電性連接母線桿電極2 2與指狀電極2 1，具有對 於矽基板1 0而言加以電性連接之第1及第2之受光面電極的 結晶系太陽能電池單元3 0。 如根據以上所述的本實施形態，加上於與上述實施形 態同樣的效果，有著可降低串連阻抗之效果。對於其他的 構成及作用效果，係與上述實施形態同一之故，省略其詳 細說明。 然而，本發明並不限於上述之實施形態，可進行各種 變更。 例如，在圖4 ( a ) ~ ( c )所示之實施形態中，做成對 於母線桿電極2 2而言，塗佈導電性電糊而形成第2之連接 膜1 7，但本發明並不限於此等，而亦可作爲對於指狀電極 21而言，塗佈導電性電糊而形成第1之連接膜15而燒結。 另外，例如，經由將指狀電極2 1，母線桿電極22浸漬 於導電性電糊之時，亦可於指狀電極2 1，母線桿電極22的 表面全面，各形成連接膜。 更且，使用於本發明之半導體基板係亦可使用單結晶 矽基板，多結晶矽基板之任一。 【圖式簡單說明】 圖1 ( a )〜（d ):顯示本實施形態之結晶系太陽能電 池單元之製造工程的剖面圖（其〇 圖2 ( a )〜（c ):顯示同實施形態之結晶系太陽能電 池單元之製造工程的剖面圖（其2 ) -20- 201145547 圖3係同實施形態之結晶系太陽能電池單元之平面圖 圖4 ( a )〜（c ):本發明之其他實施形態之剖面圖 圖5 ( a ):顯示以往之結晶系太陽能電池的單元構造 槪略圖、（b ):顯示以往之結晶系太陽能電池的單元構 造平面圖 t主要元件符號說明】 1 :太陽能電池用基板 io:矽基板（半導體基板） 11: n +型半導體層（第1導電型層） 1 2 :反射防止膜 13 : P +型半導體層（第2導電型層） 1 4 :背面電極層 15 :第1之連接膜 1 6 :第1之燒結連接膜 1 7 :第2之連接膜 1 8 :第2之燒結連接膜 2 1 :指狀電極（第1之受光面電極） 22 :母線桿電極（第2之受光面電極） 3 〇 :結晶系太陽能電池單元 -21 -BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a light-receiving surface electrode of a crystalline solar cell, particularly a solar cell using a germanium substrate. [Prior Art] Fig. 5(a) shows a schematic diagram of a cell structure of a conventional crystal solar cell, and Fig. 5(b) is a plan view showing a cell structure of a conventional crystal solar cell. As shown in Fig. 5 (a) and (b), the unit 1〇1 of the conventional crystalline solar cell is attached to the front side (injected light: 1 〇〇 side) of the ruthenium substrate 103 on which the texture 102 is formed, The n + -type semiconductor layer 104 is formed in sequence, and the anti-reflection film 1 is formed. Further, on the anti-reflection film 105, the light-receiving surface electrode 106 (the bus bar electrode 16a and the finger electrode 106b) extending in a straight line is formed. It is formed in connection with the n + -type semiconductor layer 104. On the other hand, for the back side surface of the ruthenium substrate 103, a Ρ + type semiconductor layer 107 and a back surface electrode 108 are sequentially formed. Conventionally, the light-receiving surface electrode 106 of a crystalline solar cell has been formed by screen printing using a silver 11 paste. However, in the prior art, in order to reduce the impedance of the light-receiving surface electrode 106, the line width of the finger electrode 106b must be increased to about 100 m, and the line width of the bus bar electrode 106a is increased to about 2 mm. As a result, in the prior art, there is a problem that the aperture ratio is as low as 93%. In addition, in screen printing, there is also a problem that the screen is in contact with the surface of the solar cell -5-201145547, and the substrate is damaged, and the mesh made of stainless steel is in contact with the stone layer to cause damage. However, as a prior art relating to the present invention, there is a constitution as shown below. [Patent Document 1] [Patent Document 1] Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. 2006-295197 [Patent Document 3] Japanese Patent Laid-Open No. 2 0 0 1 - 1 1 8 4 2 5 OBJECT OF THE INVENTION [Problem to be Solved by the Invention] The present invention has been made in order to solve the problems of the prior art, and it is an object of the invention to provide light-receiving of a solar cell unit capable of increasing an aperture ratio. Surface electrode forming technology. Further, another object of the present invention is to provide a light-receiving surface electrode forming technique of a solar battery cell which does not cause damage to the ruthenium layer. In order to solve the problem, the present invention provides a semiconductor substrate having a first conductivity type layer on the surface side of the light incident side and a second conductivity type layer on the back surface side, and the semiconductor substrate. The first conductivity type layer is provided with an antireflection film and a light receiving surface electrode, and a rear surface electrode for connection is provided on the second conductivity type layer of the semiconductor substrate -6-201145547, and the light receiving surface electrode is via a conductor. In the present invention, the crystal-based solar cell unit composed of the wire is also effective in the case where the wire is made of gold, silver, copper, aluminum, fine, or the like. In the present invention, the light-receiving surface electrode is also electrically connected to the first conductive type layer of the semiconductor substrate by a connection film made of a conductive sintered body containing a glass frit. In the present invention, the light receiving surface electrode includes a first light receiving surface electrode provided on the first conductive type layer of the semiconductor substrate, and a second light receiving surface electrode provided on the first light receiving surface electrode. The first light-receiving surface electrode is electrically connected to the first conductive type layer of the semiconductor substrate by the first connection film formed of the conductive sintered body, and the second light-receiving surface electrode is It is also effective to electrically connect the second connection film formed of the conductive sintered body to the first light-receiving surface electrode. On the other hand, the present invention is a solar cell in which a first conductivity type layer is provided on the surface side of the light incident side and a reflection preventing film is provided on the first conductivity type layer of the semiconductor substrate having the second conductivity type layer on the back side. When the conductive paste is sintered by using a conductive paste containing a glass frit, the light-receiving surface electrode formed by the wire formed by the conductor is fixed to the solar cell substrate while having a substrate The light-receiving surface electrode is a method for producing a crystalline solar battery cell in which the first conductive type layer of the semiconductor substrate is electrically connected. In the present invention, the light-receiving surface electrode includes the first and second light-receiving surface electrodes, and the conductive film is formed by drying and drying the conductive paste on the anti-reflection film to form a first connection film. a process of arranging the first light-receiving surface electrode on the first connection film and a process of sintering the first connection film, and coating and drying the conductive paste on the first light-receiving surface electrode. It is also effective in the case of the second connection film and the case of sintering the second connection film. In the present invention, the light-receiving surface electrode having the connection film formed by the wire coating and drying of the conductive paste is disposed on the solar cell substrate, and the light-receiving surface electrode is sintered. The case of the connection film is also effective. In the present invention, the process of applying the conductive paste described above is also effective in the case of the composition of the dispensing method or the ink jet method. In the case of the present invention, the light-receiving surface electrode is formed by wire bonding of a conductor, and compared with the light-receiving surface electrode of the conventional screen printing, the light-receiving surface can be formed when the electrode having the same wiring resistance is formed. As a result, the width of the electrode is made very small. As a result, the aperture ratio of the solar cell unit of 93% in the prior art can be greatly improved to 99%. Further, in the case of the present invention, when the light-receiving surface electrode is fixed to the solar cell substrate by application and sintering of the conductive paste, the coating method of the conductive paste does not contact the solar cell substrate. There is no case of screen printing as in the past, the substrate is broken, and damage to the ruthenium layer is caused. -8 - 201145547 Further, in the present invention, the light-receiving surface electrode formed by wire bonding is placed on the anti-reflection film by a conductive paste, and in this state, the conductive paste containing the glass frit is sintered. In the case of the first connection film, the first connection of the light-receiving surface electrode and the semiconductor substrate can be reliably electrically connected by the sintering of the connection film by the reaction between the anti-reflection film and the first connection film. Conductive layer. [Effect of the Invention] According to the present invention, the aperture ratio of the crystalline solar cell can be greatly improved. [Embodiment] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 (a) to (d) show a cross-sectional view (1) of a manufacturing process of the crystalline solar cell of the present embodiment, and Figs. 2(a) to (c) show a crystalline solar cell of the same embodiment. A sectional view of the manufacturing process of the unit (2). Further, Fig. 3 is a plan view of a crystalline solar battery II of the same embodiment. As shown in Fig. 1 (a), in the present embodiment, first, a front side surface (a surface on the incident side) of a tantalum substrate (semiconductor substrate) 1 on which a texture (not shown) is formed is sequentially prepared. The n + -type semiconductor layer 1 having the first conductivity type layer is formed, and the anti-reflection film 12 is formed on the back side, and the P + -type semiconductor layer 13 of the second conductivity type layer is sequentially formed, and the solar energy of the back electrode layer 14 is formed. Battery substrate 1. -9 - 201145547 In the case of the present invention, the material of the anti-reflection film 12 is not particularly limited. However, from the viewpoint of ensuring reactivity with the conductive paste at the time of sintering described later, it is preferable to use tantalum nitride. (SiN), cerium oxide (SiO 2 ), titanium oxide (Ti 〇 2). In addition, the thickness of the anti-reflection film 12 is not particularly limited, but it is preferably from 100 to 500 nm from the viewpoint of reducing the reflectance. However, as the material of the back electrode layer 14, for example, silver (Ag is preferably used. ) Electric paste. Next, as shown in FIG. 1(b), a plurality of first connection films (connection films) 15 formed of a conductive paste described later are applied to the surface of the anti-reflection film 12 at a predetermined interval. Then, the first connecting film 15 of these first is dried. Here, the position at which the first connection film 15 is formed is applied to a position at which the position of the finger electrode (first light-receiving surface electrode) 2 1 to be described later is provided, for example, coating is formed with the finger electrode 2 The length of 1 can be the same length. In the case of the present invention, the coating method of the first connecting film 15 is not particularly limited, but from the viewpoint of accurately forming the first connecting film 15, a method via a dispenser or a spray is employed. The method of ink is better. Further, the width of the first connecting film 15 is not particularly limited. However, from the viewpoint of further increasing the aperture ratio of the solar cell, the width of the first connecting film 15 is preferably smaller than the width of the finger electrode 2 1 . Specifically, the width of the first connecting film 15 is preferably set to 5 to 15/z mm. On the other hand, the thickness of the first connecting film 15 is not particularly limited to -10-201145547, but it is a more anti-reflection film from the viewpoint of ensuring sufficient bonding strength and further increasing the aperture ratio of the solar cell. 12 is thicker. Specifically, it is preferable to set the thickness of the first connecting film 15 to 500 to 1000 nm. As the conductive paste for use in the first connection film 15 , for example, a conductive paste having a conductivity can be preferably used in the conductive paste according to JP-A No. 2006-2 95197. Metal, and no machine binder, organic medium. Hereinafter, each component will be described. As the conductive metal which can be contained in the conductive paste used in the present invention, silver particles are mentioned, and silver particles are most preferable. The silver particles are preferably formed into a sheet form or a powder form. In the case of the present invention, the particle diameter of the silver particles of the conductive paste is not particularly limited, but the influence of the sintering characteristics is considered (the silver particles having a large particle diameter are slower than the silver particles having a small particle diameter). When the speed is sintered and the ease of coating, the average particle diameter of the silver particles is preferably 3.0 to 15.0 #m, and more preferably 5.0 to 1 1.0 // m. When the particle size of the silver particles is smaller than 3.0 // m, the silver conductive electric paste exhibits the characteristics of the six-electrode sintering, which is caused by the mismatch with the sintering speed of the aluminum electric paste, and is generated between the two electrodes. The tendency to crack. On the other hand, when the particle diameter of the silver particles is larger than 15.0 // m, the electrical conductivity is lowered and the strength of the electrode film is decreased. This reason is due to insufficient sintering. The silver particles contained in the conductive paste are preferably high in purity (-11 - 201145547 99% or more), but may be used in an amount of less than 99% in purity in accordance with the electrical requirements of the electrode pattern. The conductive metal which is optimal in the conductive paste is silver particles as described above, but a conductive metal other than silver can be used in the same manner. For example, metals such as copper (Cu), gold (Au), palladium (Pd), and platinum (Pt) are useful. Additionally, alloys or mixtures of the foregoing metals are also useful in the present invention. For example, 'Cu- Au, Ag-Pd' Pt- Au, etc. can be used. The content of the conductive metal in the conductive paste is not particularly limited as long as it can be used for the purpose of the invention. From the viewpoint of ensuring conductivity, for example, the weight of the conductive paste is silver particles. As a standard, it is preferable to contain in an amount of 40 to 93% by mass. However, for the purpose of improving the desired characteristics, it is also possible to add a mark (A1) to the conductive paste. The conductive electric paste used in the present invention contains an inorganic binder. As such an inorganic binder, a glass frit (fine particles) having a softening point of 450 to 5 50 ° C can be preferably used. Such a glass frit is obtained by firing a conductive paste at 60 to 80 ° C, suitably sintering and wetting, and suitably bonding the substrate 10 . When the softening point of the glass frit is lower than 405 °C, the sintering becomes excessive, and the effect of the present invention cannot be sufficiently obtained. On the other hand, when the softening point of the glass frit is higher than 550 °C, there is a case where the adhesive strength is not sufficiently exhibited and the liquid phase sintering of silver cannot be promoted. The reason is due to the fact that sufficient melt flow does not occur during sintering. -12- 201145547 In this specification, as a softening point, it is applicable via ASTM (American Society for Testing and Testing and Με.terials) C338-57 The composition specified by the fiber elongation method. The glass frit contained in the conductive paste is not particularly limited. However, when both the softening point range and the glass fusibility are considered, for example, silicate glass or borosilicate glass can be used most. However, it is also possible to use a glass which does not contain lead such as zinc borosilicate. The content of the glass frit as the inorganic binder is not particularly limited as long as it is a target amount of the invention, but it is preferably 2.0 to 10.0% by mass based on the total weight of the conductive paste. More preferably 3 〇 ~ 6.0% by mass. When the content of the glass frit is less than 2.0% by mass, the adhesive strength is insufficient. On the other hand, when the amount of the glass frit is higher than that of 〇. 〇% by mass, for example, there is a work for post-processing. The pattern addition project performed is hindered by glass float ing or the like. The conductive electric paste used in the present invention contains an organic medium. As the organic medium contained in the conductive electric paste, an inactive liquid can be used as such an inactive liquid, and as the organic liquid, for example, an alcohol; an ester of an alcohol (such as an acetate or a propionate) can be used. ): starch (such as the composition of pine and terpineol): resin (polymethacrylate, etc.) or ethyl cellulose in pine oil solution or glycol ether ethyl acetate solution, or such as ethyl cellulose Various solutions of the alcohol solution. In the present invention, as the organic medium, a solution of ethyl alcohol in an alcohol solution (ethylcellulose content = 5 to 50% by mass) can be preferably used. The content of the organic medium is preferably 5 to 50% by mass based on the total weight of the electrically conductive paste. For the conductive electric paste used in the present invention, a tackifier or a stabilizer, or a general additive may be added. When an additive is used, a tackifier (adhesive), a stabilizer, or the like may be added, or a dispersant, a viscosity adjuster, or the like may be added as another general additive. The amount of the additive is determined based on the characteristics of the conductive paste obtained in the end, and the manufacturer concerned can make a decision. However, several additives can also be used. The conductive electric paste used in the present invention preferably has a viscosity within a specific range. The conductive electric paste can be obtained by adding the above-mentioned adhesion-imparting agent (tackifier) in order to impart an appropriate viscosity. The conductive electric paste used in the present invention can be produced by mixing the above components with three known mixers. The viscosity of the conductive paste used in the present invention is not particularly limited, but is measured using a Brookfield HBT viscometer and a #14 axial force measuring cup at a rotation number of 1 O rpm and a temperature of 25 ° C. It is better to adjust to 50 to 300 Pa · S. In the present embodiment, the first connecting film 15 made of the conductive paste described above is applied to the anti-reflection film 1 2 in multiple layers, and then the first connecting film of '-14 - 201145547 is used. 1 5 dry. In this case, the ideal drying temperature is 1 8 〇 t: or less. Further, as shown in Fig. 1 (c), the finger electrodes 21 formed by the wire bonding are placed on the first connection film 5 of each of the first layers, and placed (placed). In the case of the present invention, the material constituting the wire of the finger electrode 2 1 is not particularly limited, but gold (Au), silver (Ag), copper (Cu) aluminum (A1), palladium (Pd) may be preferably used. Or the composition of these alloys. Among them, silver (Ag) is preferred from the viewpoint of improving conductivity. However, the cross-sectional shape of the wire constituting the finger electrode 2 1 is a perfect circular shape, and the smaller the diameter is, from the viewpoint of increasing the aperture ratio. However, in consideration of the strength required for the electrode or the magnitude of the wiring impedance, the diameter is preferably 10 to 100 μm. Further, the solar cell substrate 1 on which the finger electrodes 21 are placed is heated and sintered in air at a temperature of 600 to 800 ° C for 2 to 15 minutes. In this case, the pressurized finger electrode 2 1 may also be used. Thereby, the glass frit of the conductive paste contained in the first connection film 15 reacts with the substance of the anti-reflection film 12, and the anti-reflection film 12 is melted, as shown in Fig. 1 (d), the first The connection film of 1 (hereinafter referred to as "the first sintered connection film") 16 is buried (fired through) in the anti-reflection film 1 2 . Further, each of the finger electrodes 21 is fixed to the first sintered connecting film 16 via the above-described sintering process. As a result, the first sintered connection film 16 is in contact with the n + -type semiconductor layer 11 and electrically connected thereto, and the finger electrode 2 1 is electrically connected by the first sintered connection film 16 of the connection film. n + -type semiconductor layer 1 1 » -15- 201145547 In this state, the width of the first sintered connecting film 16 is smaller than the width of each of the finger electrodes 2 1 . However, the silver paste of the surface electrode layer 14 is also fired through the above-described sintering process to form the sintered back electrode layer 14a. Thereafter, as shown in Fig. 2 (a), the second connecting film 17 made of the conductive paste is applied to each of the finger electrodes 21, and then dried. In the case of the present invention, the method of applying the second connecting film 17 is not particularly limited, but from the viewpoint of accurately forming the second connecting film 17 with a precision, a method via a dispenser, or via an ink jet The method is better. Further, the width of the second connecting film 17 is not particularly limited. However, from the viewpoint of further increasing the aperture ratio of the solar cell, the width of the second connecting film 17 is reduced from the width of the bus bar electrode 22 to be described later. (the length in the direction perpendicular to the extending direction of the bus bar electrode 22) is preferable. Specifically, the width of the second connecting film 17 is set to 5-15; / m is preferable. However, the ideal drying temperature of the second connecting film 17 is 180 ° C or less. On the other hand, the thickness of the first connecting film 15 is set to 5 〇〇 to 1000 nm, more preferably, as shown in Fig. 2 (b). In the second connection film 17, the bus bar electrodes 22 formed by the wire bonding are placed and placed (placed). In the case of the present invention, the material constituting the bonding of the bus bar electrode 22 is not particularly limited, but gold (Au), silver (Ag), copper-16-201145547 (Cu) aluminum (A1), palladium can be preferably used optimally. (Pd), or the composition of these alloys. Among them, silver (Ag) is preferred from the viewpoint of improving conductivity. However, the cross-sectional shape of the wire constituting the bus bar electrode 22 is a perfect circular shape. From the viewpoint of increasing the aperture ratio of the solar cell, the smaller the diameter, the better. However, when considering the strength required for the electrode or the magnitude of the wiring impedance, the diameter is preferably 120 to 500 #m. Further, the solar cell substrate 1 on which the bus bar electrode 22 is disposed is heated and sintered in the air at a temperature of 60 to 80 ° C for 2 to 15 minutes. In this case, the pressure bus bar electrode 22 may also be used. Thereby, the second connection film 17 is sintered, and the respective finger electrodes 21 are fixed to the sintered second connection film (hereinafter referred to as "second sintered connection film") 18, The bus bar electrode 22 is fixed to the second sintered connecting film 18. As a result, as shown in FIG. 2(c) and FIG. 3, the bus bar electrode 22 and the finger electrode 21 are electrically connected by the second sintered connection film 18 of the connection film, and the obtained result is obtained for the ruthenium substrate 10. The crystal of the first and second light-receiving surface electrodes electrically connected is a solar cell 30. As described above, in the present embodiment, the finger electrode 2 1 and the bus bar electrode 22 of the light-receiving surface electrode are formed by wire bonding of the conductor, and compared with the light-receiving surface electrode of the conventional screen printing. In the case of forming an electrode having the same wiring resistance, the width of the light-receiving surface electrode can be greatly reduced. As a result, the opening rate of the crystalline solar cell can be greatly improved. In the present embodiment, in the case where the finger electrode 21 and the bus bar electrode 22 are fixed to the solar cell substrate 1 by coating drying and sintering via a conductive paste, the conductive paste is used. The coating means is not in contact with the solar cell substrate 1, and there is no case where the substrate is broken and the ruthenium layer is damaged as in the case of conventional screen printing. Further, in the present embodiment, the finger electrode 2 1 ' formed by wire bonding is placed on the anti-reflection film 1 2 by a conductive paste, and in its state, the conductive paste containing the glass frit is sintered. In the case of the first connection film 15 of the first, the first connection of the sintered connection film 16 can be reliably electrically connected to the fingers via the firing through the reaction between the anti-reflection film 12 and the first connection film 15 The electrode 21 and the n + -type semiconductor layer 11 of the semiconductor substrate 10. 4 (a) to (c) show other embodiments of the present invention, and the same portions as those of the above-described embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted. In the present embodiment, first, as described with reference to FIGS. 1(a) to 1(d), when the conductive paste is applied, dried and sintered, the solar cell substrate 1 is used. The sintered connection film 16 of 1 is electrically connected to the finger electrode 21 and the 11 + type semiconductor layer 11. Thereafter, as shown in FIG. 4(a), a plurality of second connecting films 1 7 formed by forming the conductive paste are applied to the surface of the bus bar electrode 22 by a predetermined interval, and then dried. . Here, the position at which the second connecting film 17 forming the surface of the bus bar electrode 22 is applied is preferably a portion to be connected to the finger electrode 2 1 provided on the solar cell substrate 1. -18- 201145547 In the case of the present invention, the coating method of the second connecting film 17 is not particularly limited, but from the viewpoint of accurately forming the second connecting film 17 on the surface of the bus bar electrode 22, A method via a dispenser, or a method via inkjet is preferred. Further, the width of the second connecting film 17 is not particularly limited 'but from the viewpoint of further increasing the aperture ratio of the solar cell unit', the length of the second connecting film 17 is reduced from the width of the bus bar electrode 22 (for the bus bar) The length of the direction in which the electrodes 22 extend in the direction perpendicularly intersecting is preferred. On the other hand, the thickness of the second connecting film 17 is not particularly limited, but it is preferably 500 to 1000 nm from the viewpoint of ensuring sufficient bonding strength and further increasing the opening ratio of the solar cell. Further, the second connection film 17 of the bus bar electrode 22 and the position of the finger electrode 2 1 of the solar cell substrate 1 are aligned in position, as shown in Fig. 4 (b), the solar cell substrate 1 is shown. The upper finger electrode 2 1 and the second connecting film 17 are placed in contact with each other (the mounting of the bus bar electrode 22 〇), and then the solar cell substrate 1 is subjected to a temperature of 00 to 800 ° C in the air. It is heated and sintered for 2 to 15 minutes. In this case, the pressurized mother green rod electrode 22 may be used. Thus, as in the above-described embodiment, the second connecting film 17 is sintered, and as shown in FIG. 4(c), each of the finger electrodes 21 is fixed to the second sintered connecting film 18, Each of the bus bar electrodes 22 is fixed to the second sintered connecting film 18. As a result, in the same manner as in the above embodiment, the bus bar electrode 2 2 and the finger electrode 2 1 are electrically connected by the second sintered -19-201145547 connecting film 18, and the germanium substrate 10 is electrically charged. The crystalline solar cell 30 of the first and second light-receiving electrodes is connected. According to the present embodiment described above, the same effect as the above-described embodiment is applied, and the effect of reducing the series resistance can be obtained. The other configurations and effects are the same as those of the above embodiment, and detailed description thereof will be omitted. However, the present invention is not limited to the above embodiments, and various modifications can be made. For example, in the embodiment shown in FIGS. 4( a ) to ( c ), the conductive bar is applied to the bus bar electrode 2 2 to form the second connecting film 17 , but the present invention The first connection film 15 is formed by applying a conductive paste to the finger electrode 21 and sintering it. Further, for example, when the finger electrode 2 and the bus bar electrode 22 are immersed in the conductive paste, the surface of the finger electrode 2 1 and the bus bar electrode 22 may be integrated to form a connection film. Further, the semiconductor substrate used in the present invention may be any of a single crystal germanium substrate or a polycrystalline germanium substrate. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 (a) to (d) are cross-sectional views showing a manufacturing process of a crystalline solar battery cell of the present embodiment (Fig. 2 (a) to (c): showing the same embodiment Sectional view of the manufacturing process of the crystalline solar cell unit (Part 2) -20- 201145547 Fig. 3 is a plan view of the crystalline solar cell of the same embodiment. Fig. 4 (a) to (c): other embodiments of the present invention Fig. 5 (a): shows a schematic diagram of a unit structure of a conventional crystal solar cell, (b): shows a unit structure plan view of a conventional crystal solar cell t. Description of main components and symbols: 1 : Substrate for solar cell io:矽 substrate (semiconductor substrate) 11: n + -type semiconductor layer (first conductivity type layer) 1 2 : anti-reflection film 13 : P + -type semiconductor layer (second conductivity type layer) 1 4 : back electrode layer 15 : first Connecting film 1 6 : first sintered connecting film 1 7 : second connecting film 1 8 : second sintered connecting film 2 1 : finger electrode (first light receiving surface electrode) 22 : bus bar electrode (first 2 light-receiving electrode) 3 〇: crystalline solar cell -twenty one -