201240127 六、發明說明： 【發明所屬之技術領域】 本發明是有關於一種太陽能電池的製造方法，特別是 指一種以RIE技術進行表面粗糙化後之製程改良的太陽能 電池的製造方法。 【先前技術】 已知太陽能電池結構中，其光照面通常具有凹凸結構 ，藉此降低太陽能電池表面對於光的反射率，提升太陽光 入射比例。上述的表面凹凸結構，可以利用反應式離子蝕 刻法（Reactive Ion Etching，簡稱RIE)蝕刻基板表面而形成 〇 參閱圖1，雖然RIE製程能蝕刻基板u而達到基板u 表面凹凸的需求，但此製程中的帶電粒子（電漿）也會因此與 基板11材料反應，使基板U表面形成一電漿破壞層12, 該電漿破壞層12的存在將增加載子的再結合率（ Recombinaticm)，因而會降低太陽能電池的光電轉換效率， 所以在RIE製程之後，必需再透過溼式蝕刻方式移除該電 焚破壞層i2’由於其材料是时⑶）、㈣氧化物（si(：^為 主，所以蝕刻液通常使用氳氧化鉀（K〇H)、氫氟酸等溶 液，當該電漿破壞層12移除後，後續再進行熱擴散 (thermal diffusion)製程使該基板u表面形成p n接面。 但是用於進行座式姓刻的儀器設備昂t，而且在熱擴 散製程之後還有另一次的溼式蝕刻必需進行，即是以移 除基板11表面因高溫所產生的Si〇2，所以如上述的太陽能 201240127 造成設備及 電池製造設備中，必、需有兩組溼式蝕刻設備 製造成本高’不利於工業量產。 【發明内容】 因此’本發明之目的，即在提供一種降低設備成本、 符合量產需求的太陽能電池的製造方法。 於是，本發明太陽能電池的製造方法，包含： ⑷利用乾式蝕刻方式蝕刻一第一導電型基板，使其表 面成為高低起伏狀，且該第一導電型基板的表面還形成一 個電漿破壞層； (B) 對該第一導電型基板進行熱擴散處理，使該第一導 電型基板形成一個位於該電漿破壞層的下方的第二導電型 射極層，並將該電漿破壞層氧化而轉變成一個氧化層，所 述熱擴散處理包括一個沉積階段以及一個驅入階段，該驅 入階段是在-驅人溫度下持續—驅人時間，該驅入溫度為 800 C〜950C，該驅入時間為20分鐘〜5〇分鐘； (C) 利用渔式姓刻方式移除該氧化層’完成製作該太陽 能電池的半成品；及 (D) 在該太陽能電池的半成品上形成電極。 當驅入溫度太低而小於80(rc時，由於溫度不足，無法 使反應氣體分子產生足夠的移動動能，因此擴散效果不好 不利於第二導電型射極層的形成，也無法將該電漿破壞 層氧化’當驅入溫度太高而大於95〇°c時，超過第一導電型 基板的耐溫範圍，會產生翹曲現象。而驅入時間過短時， 反應氣體分子未能充分擴散，亦不利於形成該第二導電型 4 201240127 射極層’該電㈣壞層也無法充分氧化；驅入時間最多50 分鐘就能達到效果，再增加時間只是造成能源浪費。 本發明之功效：透過改善熱擴散處理的驅入階段，使 電漿破壞層氧化’並利用熱擴散處理之後的溼式蝕刻去除 該氧化層，使本發明可以省略熱擴散處理前㈣式钱刻:、 如此可以降低設備成本、有利於量產，而且製作出的太陽 能電池仍然維持一定以上的轉換效率。 【實施方式】 有關本發明之前述及其他技術内容'特點與功效，在 以下配合參考圖式之—個較佳實施例及數個實驗例的詳細 說明中，將可清楚的呈現。 參閱圖2，本發明製造方法之較佳實施例，用於製造一 太陽能電、池’所述太陽能電池包括丨下往上疊置的一第一 導電型基板2、一第二導電型射極層4、一抗反射層5,以 及二個各別位於該第—導電型基板2的下表面及抗反射層5 的表面的電極6。 參閱圖3、4,本發明太陽能電池的製造方法包含： ⑴進行步驟71:準備該第一導電型基板2，本實施例 為P型半導體石夕（Si)基板，實施時不限於此，也可以使用n 型基板。 ⑺進行步驟72:利用乾式敍刻方式餘刻該第—導電型 基板2的表面，本實施例是使肢應式離子㈣法咖“ -Etching，簡稱Rm)，並以％、a* 〇2混合作為反應 氣體使第|電型基板2的表面成為高低起伏狀也就 201240127 是形成凹Λ狀的粗糙微結構（Texturing)e而且因為該第一 導電型基板2的表面會與電漿產生反應，因此會在此凹凸 狀的粗链微結構表面形成一個電漿破壞層3,該電漿破壞層 3材料主要為矽及矽的氧化物（Si〇j。 (3)進行步驟73:對該第一導電型基板2進行熱擴散處理 ，所述熱擴散處理包括一個沉積階段以及一個驅入（drive_in) 階段。首先為沉積階段，將該第一導電型基板2置入一高溫 爐管，爐管内的溫度約為750〇c〜8〇(rc，並且在爐管内通入 一反應氣體’本實施例為N^POCl3(三氯氧磷）、〇2及N2的 混合氣體，但不限於此，並進一步於該第一導電型基板2表 面沉積磷（P)。 接著進行驅入階段，該驅入階段是在一驅入溫度下持續 一驅入時間，該驅入溫度為8〇(rc〜95(rc ,較佳地為81〇它 〜950 C，更佳地為850°C〜90CTC ;該驅入時間為2〇分鐘〜 50分鐘，較佳地為25分鐘〜37·5分鐘，使該第一導電型基 板2表面的磷（p)進入該第一導電型基板2的表層，進而在該 電漿破壞層3下方形成η型的第二導電型射極層4,其材料 主要為磷玻璃（PSG)。 而且在驅入階段中，反應氣體分子也會擴散進入該電漿 破壞層3,並因較高的溫度與時間之設定’使其氧化而轉變 成為一個氧化層3，’該氧化層3,材料主要為二氧化矽、磷與 矽的氧化物等。 需要說明的是，若第一導電型基板2使用η型半導體， 則熱擴散處理而形成的第二導電型射極層4為卩型半導體。 6 201240127 :(4)進订步驟74 :利用溼式蝕刻方式移除該氧化層3,， 、h第一導電型射極層4露出。本實施例使用氫氟酸（HF)等 溶液作為蝕刻液。 一 (5)進行步驟75 ··在該第二導電型射極層4的表面形成 氮化矽之抗反射層5 ,抗反射層5能降低太陽光反射，提升 光線入射比例。於實施上’可以利用濺鍍（Sputtering)或電 漿輔助化學氣相沉積（PECVD)等技術進行。 此時已完成製作該太陽能電池的半成品，但須注意的 是形成抗反射層5並非必要步驟，因此太陽能電池的半 成品中’也可以不包含該抗反射層5。 (6) 進行步驟76 :在該太陽能電池的半成品上形成電極 6，電極6主要是透過網印的方式，形成於抗反射層5的上 表面及該第一導電型基板2的下表面。其中圖3中電極6 之型態僅為示意而非限定，亦可為其他設計之態樣。 (7) 進行步驟77 :將進行完步驟76的樣品置於高溫的燒 結爐中，燒結爐内有複數個溫度不同的高溫區域，爐内的 滾輪帶動樣品持續前進並且受到不同高溫的燒結，電極6 因此能牢固地附著，如此即完成太陽能電池的製作。 本發明相對於現有製程而言’主要是省略熱擴散處理 前的渔式姓刻’並且改良熱擴散處理的驅入階段，藉由驅 入溫度及驅入時間的配合，能夠在形成該第二導電型射極 層4時，還使該電漿破壞層3氧化，其優點在於：現有太 陽能電池製程中，在熱擴散處理之後原本就必需進行溼式 触刻，又因為氫氟酸溶液對於氧化物有良好的蝕刻效果， 7 201240127 所以本發明直接利用此渔式钮刻步驟移除該氧化層3，，而 且氧化層3’是透過氧化該電漿破壞層3而得，所以氧化層 3’的厚度原則上相對於電漿破壞層3更厚，較容易控制將其 完全蝕刻，並避免傷害該第二導電型射極層4。 參閱表一’以下透過實驗例證明本發明製造出的太陽 能電池仍然具有良好的性能。表一的V。。代表開路電壓，Js£ 代表短路電流’ F.F值代表mi factor，Eff.為轉換效率。在 本發明實驗例1〜8所限定的驅入溫度及驅入時間範圍内， 各樣品的短路電流、F.F值及轉換效率都能達到一定的標準 反觀比較例1，其驅入溫度為780 C而低於800°C，反麻氣 體分子的移動動能不足、擴散效果不好，不利於第二導電 型射極層4的形成，其電漿破壞層3也無法充分氧化及完 全移除，造成比較例1的短路電流及轉換效率較差。 【表一】 樣品 驅入溫度(°C ) 驅入時間(分鐘） V〇c(V) Jsc(mA/cm2) F.F.值 Eff (%) 實驗例1 800 25 0.615 34.15 77.45 16 27 實驗例2 800 37.5 0.616 34.21 77.26 16 28 實驗例3 820 37.5 0.615 34.26 77.51 16 33 實驗例4 850 37.5 0.615 34.51 77.39 16 42 實驗例5 950 37.5 0.615 Ί 34.74 77.36 16 53 實驗例6 900 25 0.615 34.45 77.38 16.39 實驗例7 900 37.5 0.616 34.67 77.13 16.47 實驗例8 900 50 0.615 35.06 77.31 16.66 比較例1 780 37.5 0.616 34.05 77.31 16.21 細上所述，本發明改善熱擴散處理中的驅入階段，並 且省略傳統方法在熱擴散處理前的溼式蝕刻，因此本發明 製程中只需要一組溼式蝕刻設備，進而降低設備成本、有 8 201240127 利於1產’而且製作出的太陽能電池仍然維持一定以上的 轉換效率’因此本發明兼顧量產的可行性及太陽能電池品 質。 惟以上所述者，僅為本發明之較佳實施例而已，當不 能以此限定本發明實施之範圍，即大凡依本發明申請專利 範圍及發明說明内容所作之簡單的等效變化與修飾，皆仍 屬本發明專利涵蓋之範圍内。 【圖式簡單說明】 圖1是一種已知太陽能電池的示意圖； 圖2是一示意圖，顯示本發明太陽能電池的製造方法 之較佳實施例製造出的太陽能電池； 圖3是該較佳實施例各步驟進行時的示意圖；及 圖4是該較佳實施例的步驟流程圖。 201240127 【主要元件符號說明】 2 ···.. ••…第一導電型基板 5 ......... •抗反射層 3 ··.·· ……電漿破壞層 6 ......... •電極 3,.... .....氧化層 71 〜77 . .步驟 4 ··.·· ••…第二導電型射極層 10201240127 SUMMARY OF THE INVENTION [Technical Field] The present invention relates to a method of manufacturing a solar cell, and more particularly to a method of manufacturing a solar cell improved by a surface roughening by RIE technique. [Prior Art] In the solar cell structure, the illuminating surface generally has a concave-convex structure, thereby reducing the reflectance of the surface of the solar cell to light and increasing the incident ratio of sunlight. The surface uneven structure described above can be formed by etching the surface of the substrate by reactive ion etching (RIE). Referring to FIG. 1, although the RIE process can etch the substrate u to meet the unevenness of the surface of the substrate u, the process is The charged particles (plasma) in the substrate also react with the material of the substrate 11 to form a plasma destruction layer 12 on the surface of the substrate U. The presence of the plasma destruction layer 12 will increase the recombination rate of the carrier, thus The photoelectric conversion efficiency of the solar cell is lowered. Therefore, after the RIE process, the electro-inflammation destruction layer i2' must be removed by wet etching because the material is time (3) and (iv) oxide (si(:^ is mainly, Therefore, the etching solution usually uses a solution of potassium pentoxide (K〇H), hydrofluoric acid or the like. After the plasma destruction layer 12 is removed, a thermal diffusion process is subsequently performed to form a pn junction on the surface of the substrate u. However, the equipment used for the seat type engraving is not necessary, and another wet etching is necessary after the thermal diffusion process, that is, the surface of the substrate 11 is removed due to the high temperature. Raw Si〇2, so as the above-mentioned solar energy 201240127 causes equipment and battery manufacturing equipment, it is necessary to have two sets of wet etching equipment, which is expensive to manufacture, which is not conducive to industrial mass production. [Invention] Therefore, the object of the present invention The method for manufacturing a solar cell according to the present invention includes: (4) etching a first conductive type substrate by dry etching to make the surface high or low. An undulating shape, and a surface of the first conductive type substrate further forms a plasma destruction layer; (B) thermally diffusing the first conductive type substrate to form the first conductive type substrate in the plasma destruction layer a second conductive type emitter layer underneath, and oxidizing the plasma destruction layer to form an oxide layer, the thermal diffusion process including a deposition stage and a drive-in stage, the drive-in stage is in-drive The temperature continues to drive time, the driving temperature is 800 C~950C, and the driving time is 20 minutes to 5 minutes; (C) Forming the oxide layer to complete the fabrication of the semi-finished product of the solar cell; and (D) forming an electrode on the semi-finished product of the solar cell. When the driving temperature is too low and less than 80 (rc, the reaction gas cannot be obtained due to insufficient temperature The molecule generates sufficient moving kinetic energy, so the diffusion effect is not good for the formation of the second conductive type emitter layer, and the plasma destruction layer cannot be oxidized. 'When the driving temperature is too high and is greater than 95 〇 ° C, the first is exceeded. The temperature resistance range of the conductive substrate may cause warpage. When the driving time is too short, the reaction gas molecules are not sufficiently diffused, which is not conducive to the formation of the second conductivity type 4 201240127 emitter layer 'the electric (four) bad layer It can't be fully oxidized; it can be achieved by driving in for up to 50 minutes, and increasing the time is just a waste of energy. The effect of the invention is that the plasma destruction layer is oxidized by improving the driving-in stage of the thermal diffusion treatment and the oxide layer is removed by wet etching after the thermal diffusion treatment, so that the invention can omit the heat diffusion treatment before the fourth :, this can reduce equipment costs, facilitate mass production, and the solar cells produced still maintain a certain conversion efficiency. [Embodiment] The above-mentioned and other technical contents of the present invention will be clearly described in the following detailed description of the preferred embodiments and the several experimental examples. Referring to FIG. 2, a preferred embodiment of the manufacturing method of the present invention is for manufacturing a solar cell, and the solar cell comprises a first conductive type substrate 2 and a second conductive type emitter stacked one above another. The layer 4, an anti-reflection layer 5, and two electrodes 6 respectively located on the lower surface of the first-conductivity-type substrate 2 and the surface of the anti-reflection layer 5. Referring to FIGS. 3 and 4, the method for manufacturing a solar cell of the present invention comprises: (1) performing step 71: preparing the first conductive type substrate 2, and the present embodiment is a P-type semiconductor stone (Si) substrate, which is not limited thereto, and is also not limited thereto. An n-type substrate can be used. (7) Step 72: Residually engraving the surface of the first conductive substrate 2 by dry stenciling, in this embodiment, the limb-type ion (4) method "-Etching, referred to as Rm", and %, a* 〇 2 Mixing as a reaction gas makes the surface of the first electric substrate 2 high and low undulating, that is, 201240127 is a rough texture forming a concave shape and because the surface of the first conductive type substrate 2 reacts with the plasma. Therefore, a plasma destruction layer 3 is formed on the surface of the embossed thick chain microstructure, and the material of the plasma destruction layer 3 is mainly an oxide of lanthanum and cerium (Si〇j. (3) Step 73: The first conductive type substrate 2 is subjected to a thermal diffusion process including a deposition stage and a drive_in stage. First, in the deposition stage, the first conductive type substrate 2 is placed in a high temperature furnace tube, the furnace The temperature in the tube is about 750 〇c~8 〇 (rc, and a reaction gas is introduced into the furnace tube. The present embodiment is a mixed gas of N^POCl3 (phosphorus oxychloride), 〇2 and N2, but is not limited thereto. And further depositing phosphorus on the surface of the first conductive type substrate 2 P). The drive-in phase is followed by a drive-in time at a drive-in temperature of 8 〇 (rc~95 (rc, preferably 81 〇 it ~ 950 C) More preferably, it is 850 ° C to 90 CTC; the driving time is 2 minutes to 50 minutes, preferably 25 minutes to 37. 5 minutes, so that phosphorus (p) on the surface of the first conductive substrate 2 enters. The surface layer of the first conductive type substrate 2 further forms an n-type second conductive type emitter layer 4 under the plasma destruction layer 3, and the material thereof is mainly phosphorus glass (PSG). Gas molecules will also diffuse into the plasma destruction layer 3, and will be converted into an oxide layer 3 due to the higher temperature and time setting, 'the oxide layer 3, the material is mainly cerium oxide, phosphorus and In the first conductive type substrate 2, when the n-type semiconductor is used, the second conductive type emitter layer 4 formed by thermal diffusion treatment is a germanium type semiconductor. 6 201240127 : (4) Step 74: The oxide layer 3 is removed by wet etching, and the first conductive type emitter layer 4 is exposed. For example, a solution such as hydrofluoric acid (HF) is used as the etching liquid. (5) Step 75 is performed. · An anti-reflection layer 5 of tantalum nitride is formed on the surface of the second conductive type emitter layer 4, and the anti-reflection layer 5 can be used. Reducing the reflection of sunlight and increasing the incident ratio of light. In practice, it can be carried out by techniques such as sputtering or plasma-assisted chemical vapor deposition (PECVD). At this point, the semi-finished product of the solar cell has been completed, but it must be noted. It is not necessary to form the anti-reflection layer 5, so the anti-reflection layer 5 may not be included in the semi-finished product of the solar cell. (6) Step 76: forming an electrode 6 on the semi-finished product of the solar cell. The electrode 6 is formed on the upper surface of the anti-reflection layer 5 and the lower surface of the first conductive type substrate 2 mainly by screen printing. The shape of the electrode 6 in FIG. 3 is merely illustrative and not limiting, and may be in other designs. (7) Performing step 77: placing the sample subjected to step 76 in a high temperature sintering furnace, wherein the sintering furnace has a plurality of high temperature regions having different temperatures, and the rollers in the furnace drive the sample to advance and are sintered at different high temperatures, the electrodes 6 Therefore, it can be firmly attached, thus completing the fabrication of the solar cell. Compared with the prior art process, the present invention mainly eliminates the fishing type before the thermal diffusion treatment and improves the driving stage of the thermal diffusion treatment, and can form the second by the combination of the driving temperature and the driving time. In the case of the conductive emitter layer 4, the plasma destruction layer 3 is also oxidized, which has the advantage that in the existing solar cell process, wet-touching is necessary after the thermal diffusion treatment, and the hydrofluoric acid solution is oxidized. The material has a good etching effect, 7 201240127. Therefore, the present invention directly removes the oxide layer 3 by using the fishing button engraving step, and the oxide layer 3' is obtained by oxidizing the plasma destruction layer 3, so the oxide layer 3' The thickness is in principle thicker relative to the plasma destruction layer 3, it is easier to control to completely etch it, and to avoid damage to the second conductivity type emitter layer 4. Referring to Table 1 below, it is exemplified by experiments that the solar cell manufactured by the present invention still has good performance. Table V. . Represents the open circuit voltage, Js £ represents the short circuit current 'F.F value represents mi factor, and Eff. is conversion efficiency. In the range of driving temperature and driving time defined in Experimental Examples 1 to 8, the short-circuit current, FF value and conversion efficiency of each sample can reach a certain standard. In Comparative Example 1, the driving temperature is 780 C. Below 800 ° C, the moving kinetic energy of the anti-anaesthetic gas molecules is insufficient, and the diffusion effect is not good, which is disadvantageous for the formation of the second conductive type emitter layer 4, and the plasma destruction layer 3 cannot be sufficiently oxidized and completely removed, resulting in The short-circuit current and conversion efficiency of Comparative Example 1 were inferior. [Table 1] Sample driving temperature (°C) Driving time (minutes) V〇c(V) Jsc(mA/cm2) FF value Eff (%) Experimental example 1 800 25 0.615 34.15 77.45 16 27 Experimental example 2 800 37.5 0.616 34.21 77.26 16 28 Experimental Example 3 820 37.5 0.615 34.26 77.51 16 33 Experimental Example 4 850 37.5 0.615 34.51 77.39 16 42 Experimental Example 5 950 37.5 0.615 Ί 34.74 77.36 16 53 Experimental Example 6 900 25 0.615 34.45 77.38 16.39 Experimental Example 7 900 37.5 0.616 34.67 77.13 16.47 Experimental Example 8 900 50 0.615 35.06 77.31 16.66 Comparative Example 1 780 37.5 0.616 34.05 77.31 16.21 As described above, the present invention improves the driving-in stage in the thermal diffusion treatment, and omits the conventional method before the thermal diffusion treatment. Wet etching, so only a set of wet etching equipment is needed in the process of the invention, thereby reducing the equipment cost, and the solar cell of the produced solar cell still maintains a certain conversion efficiency. Feasibility and quality of solar cells. The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a known solar cell; FIG. 2 is a schematic view showing a solar cell manufactured by a preferred embodiment of the method for fabricating a solar cell of the present invention; FIG. 3 is a preferred embodiment A schematic diagram of each step as it proceeds; and Figure 4 is a flow chart of the steps of the preferred embodiment. 201240127 [Description of main component symbols] 2 ···.. ••...first conductivity type substrate 5 ..........anti-reflection layer 3 ·····...plasma destruction layer 6 .. . . . • Electrode 3, ........ Oxide layer 71 to 77. Step 4 ·····••...Second conductive emitter layer 10