201222653 六、發明說明： 【發明所屬之技術領域】 本發明係關於-種於石夕晶片基板表面形成微孔結構或 凹槽結構之方法，尤指一種藉由貴金屬粒子配合特定蝕刻 水溶液之使用以便在石夕晶片基板表面形成微孔結構或 結構之化學蝕刻方法。 a 【先前技術】 近年來國際能源（特別是石油）價格日益高漲，且能 源需求亦日趨緊張。再生能源是一種綠色能源且不危害環 境，其中太陽能電池是一種非常有前景的乾淨能源，其可 直接從陽光產生電能。太陽能電池是一種能量轉換的光電 元件，它是經由太陽光照射後，把光的能量轉換成電能。 不過目前必須有效地降低太陽能電池的生產成本，才能被 廣泛接受而成為主要電力來源，研究指出矽晶片成本已占 結晶矽（crystalline silicon)太陽能電池模組總成本的三分之 一強。因此’為了降低成本，利用多晶矽晶片基板 (multi_crystalline silicon wafer substrate)製作太陽能電池， 及提高太陽能電池的發電效率，已成為重要發展方向。 習知的結晶矽太陽能電池具有層狀的堆疊結構，主要 包含矽晶片基板、表面鈍化/抗反射層以及電極；而矽晶片 基板包含一淺層的P-N接面。表面鈍化/抗反射層的功能之 一係在於減少入射光的反射機率，即提高矽晶片基板的光 吸收率以增進太陽能電池的光電轉換效率。 201222653 一般來說’除了表面鈍化/抗反射層外，太陽能電池之 光照面，即矽晶片基板上表面都會先經過表面制絨化處理 (surface texturing)，更進一步地減少入射光的反射率，以降 低反射損失(reflection loss)並改善光捕捉(light-trapping)特 性0 近來所有高效率石夕晶（crystalline silicon)太陽電池，在 石夕晶片基板上表面均經過表面制絨化處理，即於石夕晶片基 板上表面蝕刻出微孔結構或凹凸結構，並可選擇性添加界 面劑（surfactant) ’提升制絨化處理的效果。 先前技術1揭示一種多孔性矽晶片基板的製造方法， 其係將表面鍍有貴金屬（翻、銀、金或把）粒子的石夕晶片 基板’浸泡於氩氟酸(hydrogen fluoride)溶液中，不須施加 電性偏壓或氧化劑即可進行化學钱刻。 先前技術2揭示一種貴金屬催化之化學蝕刻法，其係 將表面/儿積有奈米銀粒子之石夕晶片基板’浸泡於氫氟酸及 過氧化氩(hydrogen peroxide)之溶液中，探討氫氟酸/過氧化 氫之不同比例，對於蝕刻效率及形態之影響。 先前技術3揭示一種矽晶片的表面制絨化 (texturization)方法，其係藉由無電解鍍覆法（electr〇less plating technique)，將晶圓表面鍍有銀粒子（或鉑粒子等貴 金屬粒子），再浸泡於氫氟酸溶液中’可選擇性添加含氧之 氧化劑（oxygen-containing oxidizer)以進行化學餘刻。 先前技術4至7等專利文獻揭示一種多孔性矽晶片基 板的製造方法，其係將表面鍍有貴金屬（例如鉑、銀、金 201222653 或把）粒子的石夕晶片基板，浸泡於包含氣氣酸及過氧化氮 之水溶液中進行化學勉刻，可在石夕晶片基板表面钱刻出一 層奈米尺度（nano-meter scaie)級之微孔層（micr〇 p〇r〇us 1啊）。此外’先前技術8至16等專利文獻亦揭露相關之 石夕晶片基板微孔或凹槽形成方法，其先於石夕晶片基板表面 沉積貴金屬’之後再以含有氫氟酸及過氧化氫及/或臭氧之 溶液中進行蝕刻。惟，由於上述先前技術於化學蝕刻步驟 時，均使用氫氟酸及過氧化氫及/或臭氧作為主要的姓刻溶 液，故在钱刻溶液之組成成分上非常單調且受限使用者 並無法根據不同的反應條件或參數進行改變。 此外，在矽晶片基板表面形成制絨化之微孔結構，對 於製造如半導體記憶體中之溝槽電容器（先前技術17)、半 導體基板封裝中之貫穿電極（先前技術18)以及喷墨印表 機的喷嘴平板（先前技術19)等元件時，均是不可或缺的 技術。因此，半導體工程師均積極思考，如何形成表面具 φ 凹凸結構之石夕晶片基板，以增加矽晶片基板之表面積。 因此，如何發明出一種於矽晶片基板表面形成微孔結 構或凹槽結構之方法，以改善先前技術之缺點，並於進行 化學#刻時提供多種可選用之钮刻劑（etchant)與含氧之氧 化劑成分，將是本發明所欲積極揭露之處。 [先前技術 1] Shinji Yae et al.，Formation of porous silicon by metal particle enhanced chemical etching in HF solution and its application for efficient solar cells, Electrochemistry Communications, 5, 8, 2003, 632-636. 201222653 [先前技術 2] C. Chartier et al.，Metal-assisted chemical etching of silicon in HF-H2O2, Electrochimica Acta，53，17， 2008, 5509-5516.201222653 VI. Description of the Invention: [Technical Field] The present invention relates to a method for forming a microporous structure or a groove structure on a surface of a stone substrate, in particular, a method of using a noble metal particle in combination with a specific etching aqueous solution. A chemical etching method for forming a microporous structure or structure on the surface of a stone substrate. a [Prior Art] In recent years, international energy (especially oil) prices have become increasingly high, and energy demand has become increasingly tense. Renewable energy is a green energy source that does not harm the environment. Solar cells are a very promising source of clean energy that can generate electricity directly from sunlight. A solar cell is an energy-converting photovoltaic element that converts light energy into electrical energy after being illuminated by sunlight. However, it is necessary to effectively reduce the production cost of solar cells, and it can be widely accepted as the main source of electricity. Research indicates that the cost of germanium wafers has accounted for one-third of the total cost of crystalline silicon solar modules. Therefore, in order to reduce costs, it has become an important development direction to fabricate solar cells using a multi-crystalline silicon wafer substrate and to improve power generation efficiency of solar cells. The conventional crystallization solar cell has a layered stacked structure mainly comprising a ruthenium wafer substrate, a surface passivation/antireflection layer and an electrode; and the ruthenium wafer substrate comprises a shallow P-N junction. One of the functions of the surface passivation/anti-reflection layer is to reduce the probability of reflection of incident light, i.e., to increase the light absorptivity of the germanium wafer substrate to enhance the photoelectric conversion efficiency of the solar cell. 201222653 Generally speaking, in addition to the surface passivation/anti-reflection layer, the illumination surface of the solar cell, that is, the upper surface of the silicon wafer substrate, is first subjected to surface texturing to further reduce the reflectance of incident light. Reducing reflection loss and improving light-trapping characteristics. Recently, all high-efficiency crystalline silicon solar cells have been surface-finished on the surface of the stone substrate. The surface of the wafer substrate is etched with a microporous structure or a concave-convex structure, and a surfactant can be selectively added to enhance the effect of the texturing process. Prior Art 1 discloses a method for manufacturing a porous tantalum wafer substrate by immersing a stone wafer substrate having a surface of a noble metal (turned, silver, gold or copper) in a hydrogen fluoride solution, Chemical charges must be applied by applying an electrical bias or oxidant. Prior Art 2 discloses a chemical etching method for noble metal catalysis in which a surface/integrated nano-silver particle substrate is immersed in a solution of hydrofluoric acid and hydrogen peroxide to investigate hydrofluorication. The effect of different ratios of acid/hydrogen peroxide on etching efficiency and morphology. Prior art 3 discloses a surface texturization method for a tantalum wafer by plating silver particles (or noble metal particles such as platinum particles) by an electr〇less plating technique. , and then immersed in a hydrofluoric acid solution 'optionally add an oxygen-containing oxidizer for chemical re-engraving. The prior art patents 4 to 7 and the like disclose a method for producing a porous tantalum wafer substrate, which is a stone substrate coated with a noble metal (for example, platinum, silver, gold 201222653 or copper) particles, and is immersed in a gas-containing acid. Chemical engraving is carried out in an aqueous solution of nitrogen peroxide, and a nano-meter scaie-level microporous layer (micr〇p〇r〇us 1) can be engraved on the surface of the stone substrate. In addition, the prior art patent documents 8 to 16 also disclose a method for forming a micropore or a groove of a related substrate, which deposits a precious metal on the surface of the stone substrate, and then contains hydrofluoric acid and hydrogen peroxide and/or Etching is carried out in a solution of ozone. However, since the above prior art uses hydrofluoric acid and hydrogen peroxide and/or ozone as the main surname solution in the chemical etching step, the composition of the solution is very monotonous and limited. Change according to different reaction conditions or parameters. Further, a napped microporous structure is formed on the surface of the germanium wafer substrate, for manufacturing a trench capacitor such as a semiconductor memory (Prior Art 17), a through electrode in the semiconductor substrate package (Prior Art 18), and an ink jet printer It is an indispensable technology when the machine's nozzle plate (previous technology 19) and other components. Therefore, semiconductor engineers are actively thinking about how to form a stone wafer substrate with a surface roughness of φ to increase the surface area of the germanium wafer substrate. Therefore, how to invent a method for forming a microporous structure or a groove structure on the surface of a germanium wafer substrate to improve the disadvantages of the prior art, and to provide a variety of optional etchants and oxygenates for chemical etching The oxidant component will be actively disclosed by the present invention. [Prior Art 1] Shinji Yae et al., Formation of porous silicon by metal particle enhanced chemical etching in HF solution and its application for efficient solar cells, Electrochemistry Communications, 5, 8, 2003, 632-636. 201222653 [Prior Art 2 C. Chartier et al., Metal-assisted chemical etching of silicon in HF-H2O2, Electrochimica Acta, 53, 17, 2008, 5509-5516.
[先前技術 3] K. Tsujino et al.，Texturization of multicrystalline silicon wafers for solar cells by chemical treatment using metallic catalyst, Solar Energy Materials and Solar Cells, 90, 1, 2006, 100-110.[Prior Art 3] K. Tsujino et al., Textured of multicrystalline silicon wafers for solar cells by chemical treatment using metallic catalyst, Solar Energy Materials and Solar Cells, 90, 1, 2006, 100-110.
[先前技術4]美國專利第6790785 B1號。 [先前技術5]美國專利第7135414 B2號。 [先前技術6]日本特許公開第2007-194485號。 [先前技術7]美國專利第7718254 B2號。 [先前技術8]日本特許公開第2005-183505號。 [先前技術9]日本特許公開第2〇〇5_142457號。 [先前技術10]曰本特許公開第2007-194485號。 [先前技術11]美國專利公開第2〇〇8/〇〇9〇〇74 A1號。 [先前技術12]美國專利第6329296 B1號。 [先前技術13]日本特許公開第2〇〇5_129741號。 [先前技術14]PCT專利公開第2003-105209號。 [先前技術15]PCT專利公開第2002-023607號。 [先前技術16]美國專利第6762134 B2號。 [先前技術17]日本特許公表第2〇〇4_514276號。 [先前技術18]日本特許公開第2〇〇4_95849號。 [先前技術19]日本特開平第u_268281號。 201222653 【發明内容】 盖，！=上3前技術之缺槭’發明人有感其未臻於完 善’遂竭其心智悉心研贫券 研見服，憑其從事該項產業多年之 研發出一種”晶片基板表面形成微孔結 構t凹槽結構之方法’以期於氫紐、過氧化氫、臭氧之 外提供更多種的化學蝕刻液組成。 儋 瘦 本發明之主要目的在提供—種於石夕晶片基板表面形成 微孔(m1Cr〇-P〇res)結構或凹槽（trench)結構之方法並原理 _由貴金屬粒子催化與其接觸之⑽^基板表㈣層之 氧化反應，以形成二氧化⑪，同時間水溶液中之酸性化合 物（如I化驗或氟化銨等）會㈣二氧切，此種連續 之夕氧化及—氧化⑦*刻反應會在與貴金屬粒子接觸處之 石夕晶片基板表面產生局部微_效果，而切晶片基板表 面形成微孔結構或凹槽結構，其可有效降财晶片基板之 表面反射率，&尚太陽能電池的發電效率，並降低製造成 本，進而達到提升太陽能電池的生產效益之目的。 為達上述目的，本發明提供一種於矽晶片基板表面形 成微孔結構或凹槽結構之方法，其步驟包含： (A)形成至少一種選自銀(Ag)、金(au)、鉑（Pt)或鈀(pd) 之貝金屬粒子於石夕晶片基板表面；（B)之後使用一触刻水溶 液對矽晶片基板表面實施化學溼蝕刻製程；蝕刻水溶液包 含至少一種可於水溶液中釋放氟離子(flu〇ride i〇n releasing) 之酸性化合物’及至少一種含氧之氧化劑 (oxygen-containing oxidizer);其中’該酸性化合物係選自 201222653 氟化銨(NHJ)、氟化氩銨(NH4HF2)、氫氟酸之金屬鹽或銨 鹽、二氟乙酸(CF3C〇2H)、三氟乙酸(cf3c〇2H)之金屬鹽或 敍鹽、四氟硼酸(HBF4)、四氟硼酸之金屬鹽或銨鹽、六氟 矽酸((NH4)2(SiF6))或六氟矽酸之金屬鹽或銨鹽；而該含氧 之氧化劑係選自過硫酸鈉(Na^Og)、過猛酸钟(KMn04)、 硝酸（ηνο3)、硝酸銨（νη4Ν03)、硫酸（h2S04)、硫酸銨 ((νΗ4)θ〇4)、過氧二硫酸銨（(ΝΗ4)Α〇8)、過氧二硫酸鉀 - (HOs)、過氣酸(HC104)、過氯酸銨(NH4C104)、過氯酸鈉 • ® (NaC1〇4)、過氣酸鉀(KC104)、過蛾酸(ΗΙ〇4 · 2H20)、過磁 酸納(NaI〇4)、過碘酸鉀(κΐ〇4)、曱磺酸(Ch3S〇2〇h)或硫酸 乙二胺（C2H10N2SO4)。 於本發明中’形成在石夕晶片基板表面之貴金屬粒子可 催化石夕晶片基板表面之氧化反應，且姓刻水溶液中之氟離 子會蝕刻二氧化矽’藉此連續反應而造成局部微蝕刻，而 在矽晶片基板表面形成微孔結構或凹槽結構。 φ 於上述之方法步驟（A)中，貴金屬粒子之粒徑尺度 ^ (Partide feature scale)可為 1 奈米（nanometer)至 5000 奈米之 間，較佳之尺度範圍在30奈米至3000奈米之間。 於上述之方法步驟(A)中’金屬粒子形成之方法可使用 無電解鑛覆法（electroless plating technique)在石夕晶片基板 表面上沉積(deposit)形成粒狀或島狀之貴金屬粒子。舉例而 言，由於矽之化學活性較低，水溶液中銀離子在石夕晶片基 板上之無電解鍍覆(electroless plating)是一種自催化還原反 應（autocatalytic reduction reaction)，在石夕晶片基板表面上還 201222653 原成銀原子，並逐漸沉積成銀粒子。 一般而言，無電解鍍覆法中使用之化學藥液之溫度、 貴金屬離子莫耳濃度與酸鹼值皆會強烈影響貴金屬離子之 還原反應（即原子沉積速率）與化學藥液之穩定度。此外， 一般可添加一還原劑（reducing agent)使貴金屬離子還原反 應速率加快，以便增加貴金屬（原子）之沉積速率。常見 之還原劑包括有次亞填酸納（s〇diuin hypophosphite monohydrate，NaH2P02.H20)、曱醛（formaldehyde，CH20)、 硫酸聯氨（hydrazine sulfate，N2H4.H2S04 )、酒石酸鈉钟 (Rochelle salt or potassium sodium tartrate ， KNaC4H4CV4H20)等化學藥劑。 於上述之方法步驟(A)中，亦可使用其他形成貴金屬粒 子的方法’例如電鍵法（electroplating technique)、電泳法 (electrophoresis technique)、網印法（stencil printing technique)、喷墨法（ink-jet printing technique)、噴賤法 (spraying technique)、濺鍍法（sputtering technique)及蒸鍍法 (evaporating technique)中之任一者。 其中電鍍法及電泳法與無電解鍍覆法有些相似性，差 異處在於前兩者有外加之電極與外加之電流，及使用不同 化學藥品。若在較短時間内使用較低之電流量，則可在矽 晶片基板表面上沉積(deposit)形成粒狀或島狀之金屬層。 其中網印法、喷墨法係使用含有貴金屬粒子之漿料 (paste) ’按照預定之圖樣(pattern)在矽晶片基板表面上進行 局部之塗佈，後續並增加一烘乾(dry)過程。其中喷濺法係 201222653 使用含有貝金屬粒子之有機溶劑（s〇lvent)，在較大面積之 範圍内機將貴金屬粒子丨麗佈在（Spray 〇nt〇)石夕晶片基板表 面上’後續並增加一烘乾過程。 其中濺鍍法(sputtering technique)係使用貴金屬之濺鍍 靶材（sputter target) ’將貴金屬粒子局部沉積（dep〇s⑴或全 部沉積在矽晶片基板表面上，後續並可選擇性地增加一圖 樣化(patterning)製程，例如使用微影（iith〇graphy)技術或硬 膜(hard mask)做一圖樣之定義及使用一蝕刻液移除外露之 貝金屬層，因而可決定貴金屬粒子之附著位置，或使貴金 屬粒子以特定圖案沉積於矽晶片基板表面。而蝕刻水溶液 可選用鹽酸(HC1)水溶液、硫酸(H2S04)水溶液、硝酸(hn〇3) 水溶液或任兩者或三者之混合水溶液。 其中蒸鐘法（evaporating technique)使用貴金屬元素蒸 鍍在（co-evaporate onto)矽晶片基板表面上，形成一貴金屬 層’後續並可選擇性地增加一圖樣化(patterning)製程，與 濺鍍法中使用之後續製程雷同。 於上述之方法中，步驟(B)係於一蝕刻水溶液中進行化 學濕钱刻，姓刻水溶液包含至少一種能於水溶液中釋放氟 離子（fluoride ion releasing)之酸性化合物，及至少一種含氧 之氧化劑（oxygen-containing oxidizer)，其中，酸性化合物 係選自：氟化銨(NH4F)、氟化氫銨(NH4HF2)、氫氟酸之金 屬鹽或銨鹽、三氟乙酸(cf3co2h)、三氟乙酸(cf3co2h)之 金屬鹽或銨鹽、四氟硼酸(HBF4)、四氟硼酸之金屬鹽或銨 鹽、六氟矽酸((NH4)2(SiF6))或六氟矽酸之金屬鹽或銨鹽； 201222653 而含氧之氧化劑係選自過硫酸鈉（NkhO8)、過錳酸鉀 (ΚΜη04)、硝酸(HN〇3)、硝酸銨(NH4N〇3)、硫酸(H2S〇4)、 硫酸銨((NH4)2S〇4)、過氧二硫酸銨((NH4)2S2〇8)、過氧二硫 酸鉀(K2S208)、過氣酸(HC104)、過氣酸銨(NH4C104)、過氯 酸鈉(NaC104)、過氣酸鉀(KC104)、過碘酸(m〇4 · 2H20)、 過碘酸鈉(NaI〇4)、過碘酸鉀(KI〇4)、甲磺酸(CH3S〇2〇H)或 硫酸乙二胺（C2H10N2SO4)。 其原理係藉由貴金屬粒子催化與其接觸之矽晶片基板 表面氧化以形成二氧化矽’同時間蝕刻水溶液中氟離子會 蝕刻二氧化矽’此連續之氧化及蝕刻反應會造成矽晶片基 板表面局部微蝕刻效果，而於矽晶片基板表面形成微孔 (micro-pores)結構或凹槽（trench)結構。 依據本發明之方法，貴金屬粒子較佳係藉由無電解鍍 覆法’將貴金屬元素鍍覆沉積於矽晶片基板表面形成貴金 屬粒子’作為後續化學濕姓刻之氧化觸媒（oxidation catalyst)。而於溼蝕刻步驟中，藉此觸媒與蝕刻液中之氧化 劑使（與貴金屬粒子的外表面接觸之）矽晶體氧化成二氧 化石夕’同時钱刻水溶液中氟離子將二氧化矽溶解於蝕刻水 溶液中之連續反應，進而繼續溶解矽晶體，因而形成（與 貴金屬粒子粒徑相近的）微孔或凹槽，並繼續朝矽晶片基 板内部延伸發展（develop)，使矽晶片基板表面形成微孔結 構或凹槽結構’並在微孔或凹槽底部殘留該貴金屬粒子。 因此’本發明由於提供各種可使用於化學蝕刻步驟中 之成分’而克服先前技術中僅能利用氫氟酸、過氧化氫、 201222653 臭氧之限制，讓使用者在進行化學⑽】時可根據不同的反 應條件或參數選擇適合的化學㈣丨液組成，❿達成理想之 餘刻效果及微孔或凹槽形態。 最後在矽晶片基板表面形成微孔結構或凹槽結構後， 可增加一去除(remove)貴金屬粒子之步驟，例如使用一蝕刻 水各液移除殘留之貴金屬粒子，*似彳水溶液可選用鹽酸 (Ηα)水溶液、硫酸(h2S〇4)水溶液、硝酸_〇3)水溶液或 其中兩者或三者之混合水溶液。 藉此本發明之-種於石夕晶片基板表面形成微孔結構 或凹槽結構之方法’係沉積至少—種貴金屬粒子，藉由貴 金屬粒子催化與其接觸之以片基板表面之氧化反應及藉 :飯刻水溶液_二氧切反應，造成石夕晶片基板局部微 刻’二便在秒晶片基板表面形成微孔結構或凹槽結構， 二可有效降低矽晶片基板之表面反射率，提高太陽能電池 二電j率，並降低製造成本，進而達到提升太陽能電池 的生產效益之目的。 【實施方式】 為充分瞭解本發明之目的、特徵及功效，錢由下述 具體之實施例’並配合所附之圖式’對本發明做一詳細說 明，說明如後： 請同時參閱第1圖及第2圖，其為本發明不同較佳具 體實施例的剖面示意圖’係用以分別顯示本發明各階段之 乂驟如圖所示，首先係提供一石夕晶片基板】，之後使用無 12 201222653 電解鑛覆法於石夕晶片基板1表面形成貴金屬粒子2。U 藉由=水溶液（圖未示）料w基板丨表面實施^ 祕f製程，以形成微孔結構或凹槽結構。 子[Prior Art 4] U.S. Patent No. 6,790,785 B1. [Prior Art 5] U.S. Patent No. 7,135,414 B2. [Prior Art 6] Japanese Patent Laid-Open No. 2007-194485. [Prior Art 7] U.S. Patent No. 7,718,254 B2. [Prior Art 8] Japanese Patent Laid-Open No. 2005-183505. [Prior Art 9] Japanese Patent Laid-Open No. 2_142457. [Prior Art 10] Japanese Patent Laid-Open No. 2007-194485. [Prior Art 11] U.S. Patent Publication No. 2/8/9, No. 74 A1. [Prior Art 12] U.S. Patent No. 6,329,296 B1. [Prior Art 13] Japanese Patent Laid-Open No. 2 No. 5_129741. [Prior Art 14] PCT Patent Publication No. 2003-105209. [Prior Art 15] PCT Patent Publication No. 2002-023607. [Prior Art 16] U.S. Patent No. 6,762,134 B2. [Prior Art 17] Japanese Patent Application No. 2_514276. [Prior Art 18] Japanese Patent Laid-Open No. 2_95849. [Prior Art 19] Japanese Patent Laid-Open No. U_268281. 201222653 [Summary content] Cover,! = The lack of technology in the previous 3 'Inventors have felt that they have not been perfected. 'Exhaustion of their minds and research and development of the plaques, with the development of the industry for many years to develop a micro-porous structure on the surface of the wafer substrate The method of the t-groove structure is to provide more kinds of chemical etching liquids in addition to hydrogen hydride, hydrogen peroxide, and ozone. The main purpose of the present invention is to provide micropores on the surface of the wafer substrate ( m1Cr〇-P〇res) Structure or Trench Structure Method and Principle _ Oxidation reaction of (10)^ substrate (4) layer catalyzed by noble metal particles to form dioxide 11, while acidic compound in aqueous solution (such as I test or ammonium fluoride, etc.) will (4) dioxotomy, this continuous oxidation and oxidation - 7 * engraved reaction will produce a local micro-effect on the surface of the stone substrate at the contact with the precious metal particles, and cut A microporous structure or a groove structure is formed on the surface of the wafer substrate, which can effectively reduce the surface reflectivity of the wafer substrate, & the power generation efficiency of the solar cell, and reduce the manufacturing cost, thereby achieving the improvement of the solar power For the above purpose, the present invention provides a method for forming a microporous structure or a groove structure on a surface of a tantalum wafer substrate, the steps comprising: (A) forming at least one selected from the group consisting of silver (Ag) and gold ( Au), platinum (Pt) or palladium (pd) shell metal particles on the surface of the stone substrate; (B) then using a etched aqueous solution to perform a chemical wet etching process on the surface of the germanium wafer substrate; the etching aqueous solution contains at least one An aqueous compound that releases fluoride ions and at least one oxygen-containing oxidizer in an aqueous solution; wherein the acidic compound is selected from 201222653 ammonium fluoride (NHJ), fluorinated Argon ammonium (NH4HF2), metal or ammonium salt of hydrofluoric acid, difluoroacetic acid (CF3C〇2H), metal or salt of trifluoroacetic acid (cf3c〇2H), tetrafluoroboric acid (HBF4), tetrafluoroboric acid a metal salt or an ammonium salt, a hexafluoroantimonic acid ((NH4)2 (SiF6)) or a metal salt or an ammonium salt of hexafluoroantimonic acid; and the oxygen-containing oxidizing agent is selected from the group consisting of sodium persulfate (Na^Og), Excessive acid clock (KMn04), nitric acid (ηνο3), ammonium nitrate (νη4Ν03), sulfuric acid (h2S 04), ammonium sulfate ((νΗ4)θ〇4), ammonium peroxodisulfate ((ΝΗ4)Α〇8), potassium peroxydisulfate-(HOs), peroxyacid (HC104), ammonium perchlorate ( NH4C104), sodium perchlorate • ® (NaC1〇4), potassium peroxylate (KC104), mothoic acid (ΗΙ〇4 · 2H20), sodium peroxyacid (NaI〇4), potassium periodate (κΐ) 〇4), hydrazine sulfonic acid (Ch3S〇2〇h) or ethylenediamine sulfate (C2H10N2SO4). In the present invention, the noble metal particles formed on the surface of the stone substrate can catalyze the oxidation reaction of the surface of the substrate, and The fluoride ion in the aqueous solution is etched to etch the cerium oxide, thereby causing local micro-etching by continuous reaction, and forming a microporous structure or a groove structure on the surface of the ruthenium wafer substrate. φ In the above method step (A), the particle size scale of the noble metal particles (Partide feature scale) may be between 1 nanometer and 5000 nanometers, preferably in the range of 30 nm to 3000 nm. between. The method of forming metal particles in the above step (A) of the method can deposit deposits of granular or island-shaped noble metal particles on the surface of the stone substrate by using an electroless plating technique. For example, due to the low chemical activity of ruthenium, the electroless plating of silver ions in the aqueous solution on the shixi wafer substrate is an autocatalytic reduction reaction, and is also on the surface of the shixi wafer substrate. 201222653 Originally formed into silver atoms and gradually deposited into silver particles. In general, the temperature of the chemical liquid used in the electroless plating method, the molar concentration of the noble metal ions, and the pH value strongly influence the reduction reaction of the noble metal ions (i.e., the atomic deposition rate) and the stability of the chemical liquid. Further, a reducing agent may be generally added to accelerate the rate of reduction of the noble metal ions in order to increase the deposition rate of the noble metal (atoms). Common reducing agents include s〇diuin hypophosphite monohydrate (NaH2P02.H20), furfural (formaldehyde, CH20), hydrazine sulfate (N2H4.H2S04), sodium tartrate clock (Rochelle salt or Potassium sodium tartrate, KNaC4H4CV4H20) and other chemicals. In the above method step (A), other methods for forming noble metal particles can also be used, such as electroplating technique, electrophoresis technique, stencil printing technique, inkjet method (ink- Any of a jet printing technique, a spraying technique, a sputtering technique, and an evaporation technique. Among them, the electroplating method and the electrophoresis method have some similarities with the electroless plating method, and the difference is that the first two have an external electrode and an applied current, and different chemicals are used. If a lower amount of current is used in a shorter period of time, a granular or island-like metal layer can be deposited on the surface of the ruthenium wafer substrate. Among them, the screen printing method and the ink jet method use a paste containing noble metal particles to perform partial coating on the surface of the tantalum wafer substrate in accordance with a predetermined pattern, followed by a dry process. Among them, the sputtering method 201222653 uses an organic solvent containing shell metal particles, and the precious metal particles are clothed on the surface of the (Spray 〇nt〇) stone substrate on a large area. Add a drying process. The sputtering technique uses a sputter target of a precious metal to deposit a precious metal particle locally (dep〇s(1) or all deposited on the surface of the germanium wafer substrate, and subsequently selectively add a patterning. (patterning) a process, such as using a lithography technique or a hard mask to define a pattern and using an etchant to remove the exposed shell metal layer, thereby determining the attachment position of the precious metal particles, or The noble metal particles are deposited on the surface of the germanium wafer substrate in a specific pattern, and the etching aqueous solution may be selected from an aqueous solution of hydrochloric acid (HC1), an aqueous solution of sulfuric acid (H2S04), an aqueous solution of nitric acid (hn〇3), or a mixed aqueous solution of any two or three. The evaporating technique uses a noble metal element to evaporate onto the surface of the wafer substrate to form a precious metal layer 'subsequently and optionally to add a patterning process, which is used in the sputtering method. The subsequent process is similar. In the above method, the step (B) is performed in an etching aqueous solution for chemical wet etching, and the surname is enzymatic solution. At least one acidic compound capable of releasing fluoride ion release in an aqueous solution, and at least one oxygen-containing oxidizer, wherein the acidic compound is selected from the group consisting of ammonium fluoride (NH4F) and ammonium hydrogen fluoride ( NH4HF2), metal or ammonium salt of hydrofluoric acid, metal or ammonium salt of trifluoroacetic acid (cf3co2h), trifluoroacetic acid (cf3co2h), tetrafluoroboric acid (HBF4), metal salt or ammonium salt of tetrafluoroboric acid, Hexafluoroantimonic acid ((NH4)2(SiF6)) or a metal salt or ammonium salt of hexafluoroantimonic acid; 201222653 The oxygen-containing oxidant is selected from the group consisting of sodium persulfate (NkhO8), potassium permanganate (ΚΜη04), nitric acid (HN〇3), ammonium nitrate (NH4N〇3), sulfuric acid (H2S〇4), ammonium sulfate ((NH4)2S〇4), ammonium peroxodisulfate ((NH4)2S2〇8), peroxydisulfate Potassium (K2S208), peroxyacid (HC104), ammonium peroxyacid (NH4C104), sodium perchlorate (NaC104), potassium peroxylate (KC104), periodic acid (m〇4 · 2H20), periodic acid Sodium (NaI〇4), potassium periodate (KI〇4), methanesulfonic acid (CH3S〇2〇H) or ethylenediamine sulfate (C2H10N2SO4). The principle is based on the ruthenium wafer substrate catalyzed by noble metal particles.The surface is oxidized to form cerium oxide. At the same time, etching the fluorine ions in the aqueous solution etches the cerium oxide. This continuous oxidation and etching reaction causes a local micro-etching effect on the surface of the germanium wafer substrate, and micropores are formed on the surface of the germanium wafer substrate. -pores) structure or trench structure. According to the method of the present invention, the noble metal particles are preferably deposited by depositing a noble metal element on the surface of the tantalum wafer substrate by an electroless plating method to form a noble metal particle as an oxidation catalyst for subsequent chemical wetness. In the wet etching step, the catalyst and the oxidant in the etching solution cause the ruthenium crystal (which is in contact with the outer surface of the noble metal particle) to be oxidized to the sulphur dioxide, while the fluorine ion in the aqueous solution dissolves the cerium oxide. The continuous reaction in the aqueous solution is etched to further dissolve the ruthenium crystal, thereby forming micropores or grooves (similar to the particle size of the noble metal particles), and continuing to develop toward the inside of the ruthenium wafer substrate, so that the surface of the ruthenium wafer substrate is microscopically formed. The pore structure or the groove structure 'and the precious metal particles remain at the bottom of the micropores or grooves. Therefore, the present invention overcomes the limitations of prior art that only hydrofluoric acid, hydrogen peroxide, and 201222653 ozone can be used because of the various components that can be used in the chemical etching step, so that the user can perform the chemical (10) according to the difference. The reaction conditions or parameters select the appropriate chemical (iv) sputum composition to achieve the desired residual effect and micropore or groove morphology. Finally, after the microporous structure or the groove structure is formed on the surface of the germanium wafer substrate, a step of removing the precious metal particles may be added, for example, using an etching water to remove residual precious metal particles, and the aqueous solution may be selected from hydrochloric acid. Ηα) an aqueous solution, an aqueous solution of sulfuric acid (h2S〇4), an aqueous solution of nitric acid (〇3), or a mixed aqueous solution of two or three of them. Therefore, the method for forming a microporous structure or a groove structure on the surface of the stone substrate of the present invention is to deposit at least a kind of noble metal particles, and the oxidation reaction of the surface of the substrate is contacted by the precious metal particles to catalyze and lend: The enzymatic solution of the rice solution _ dioxolysis reaction causes the Si Xi wafer substrate to be partially micro-etched to form a microporous structure or a groove structure on the surface of the second wafer substrate, which can effectively reduce the surface reflectance of the ruthenium wafer substrate and improve the solar cell 2 The rate of electricity is reduced, and the manufacturing cost is reduced, thereby achieving the purpose of improving the production efficiency of the solar cell. [Embodiment] In order to fully understand the object, features and effects of the present invention, the present invention will be described in detail by the following specific embodiments 'with the accompanying drawings', and the description is as follows: Please also refer to FIG. And FIG. 2 is a schematic cross-sectional view showing different preferred embodiments of the present invention for respectively showing the stages of the present invention as shown in the figure, firstly providing a stone wafer substrate, and then using no 12 201222653 The electrolytic metal coating method forms the noble metal particles 2 on the surface of the Shihua wafer substrate 1. U is processed by the surface of the substrate by means of an aqueous solution (not shown) to form a microporous structure or a groove structure. child
刖述❹j水溶液包含選自氣化錢(nH4F)、氣化氣 (NH4HF2)、氫氟酸之金屬鹽或錢鹽、三氟乙酸(❿⑺、、 一氟乙自文(CF3C〇2H)之金屬鹽或銨鹽、四氟硼酸(HBF4)、四 氟硼酸之金屬鹽或銨鹽、六氟矽酸((NH4)2(SiF6))或六轰功 酸之金屬鹽或銨鹽之至少一種可於水溶液中釋放氟離子之 酸性化合物；以及選自過硫酸鈉（Nad2。8)、過錳酸鉀 (ΚΜη04)、硝酸(hn〇3)、硝酸銨(NH4N〇3)、硫酸(h2s〇4)、 硫酸銨((NHASO4)、過氧二硫酸銨((NH4)2S2〇8)、過氧二硫 酸鉀(κΛ〇8)、過氣酸(HCl〇4)、過氣酸銨(NH4C104)、過氣 酸鈉(NaC104)、過氣酸鉀(KCl〇4)、過碘酸(ηι〇4 · 2H20)、 過碘酸鈉(NaI04)、過碘酸鉀(KIO4)、曱磺酸(CH3S020H)或 硫酸乙二胺（C2H10N2SO4)之至少一種含氧之氧化劑。 由於貴金屬粒子2於蝕刻進行時存在於微孔結構或凹 槽結構内，故可於含有貴金屬粒子2之矽晶片基板1表面 使用包含鹽酸、硝酸及硫酸之混合蝕刻水溶液，實施一貴 金屬粒子去除之步驟，將貴金屬粒子2完全去除，以完成 矽晶片基板1表面之微孔結構或凹槽結構。 [實施例] 實施例1 準備一經切割、表面光滑之單晶矽晶片（尺寸約150 厘米），並配製下列水溶液。 13 201222653 清洗液：30 %過氧化氫及98 %濃硫酸以1:4(體積比） 混合之水溶液。 無電解鑛覆藥液(electroless plating solution):含有 0.05The aqueous solution of ❹j contains a metal selected from the group consisting of gasification (nH4F), gasification gas (NH4HF2), hydrofluoric acid metal salt or money salt, trifluoroacetic acid (❿7), and fluoroethylene (CF3C〇2H). At least one of a salt or an ammonium salt, a tetrafluoroboric acid (HBF4), a metal salt or an ammonium salt of tetrafluoroboric acid, a hexafluoroantimonic acid ((NH4)2 (SiF6)) or a metal salt or an ammonium salt of a hexahydroic acid An acidic compound that releases fluoride ions in an aqueous solution; and is selected from the group consisting of sodium persulfate (Nad 2. 8), potassium permanganate (ΚΜη04), nitric acid (hn〇3), ammonium nitrate (NH4N〇3), and sulfuric acid (h2s〇4) ), ammonium sulfate ((NHASO4), ammonium peroxodisulfate ((NH4)2S2〇8), potassium peroxydisulfate (κΛ〇8), peroxyacid (HCl〇4), ammonium peroxyacid (NH4C104) , sodium percarbonate (NaC104), potassium peroxylate (KCl〇4), periodic acid (ηι〇4 · 2H20), sodium periodate (NaI04), potassium periodate (KIO4), sulfonic acid ( At least one oxygen-containing oxidizing agent of CH3S020H) or ethylenediamine sulfate (C2H10N2SO4). Since the noble metal particles 2 are present in the microporous structure or the groove structure during etching, the surface of the wafer substrate 1 containing the noble metal particles 2 may be Use containing hydrochloric acid, The mixed etching solution of acid and sulfuric acid is subjected to a step of removing the noble metal particles, and the noble metal particles 2 are completely removed to complete the microporous structure or the groove structure on the surface of the tantalum wafer substrate 1. [Examples] Example 1 Preparation for cutting, A single-crystal germanium wafer with a smooth surface (about 150 cm in size) and the following aqueous solution is prepared. 13 201222653 Cleaning solution: 30% hydrogen peroxide and 98% concentrated sulfuric acid in an aqueous solution of 1:4 (volume ratio). Electroless plating solution: contains 0.05
Mole/L硝酸銀(AgN03)及1.0 Mole/L氫氧化鈉(NaOH)混合 之水溶液。 餘刻液：10 %氟化銨及30 %過氯酸以1〇 : 1 (體積比) 混合之水溶液。 使該晶片浸泡在清洗液中1〇分鐘，以洗淨該晶片。接 著’將該晶片浸泡在無電解鍍覆藥液中約2〇分鐘，以使銀 離子形成銀粒子沉積於該晶片表面。其次，將沉積有銀粒 子之晶片浸泡在蝕刻液中1〇分鐘至30分鐘。 實施例2 除將實施例1中蝕刻液組成更換為2〇 %氟化氫銨及3〇 %硝酸銨以10: 1 (體積比）混合之水溶液外，其餘實施條 件及步驟均與實施例1相同。 實施例3 除將實施例1中蝕刻液組成更換為1〇 %四氟硼酸及3〇 %過碘酸以10 . 1 (體積比）混合之水溶液外，其餘實施條 件及步驟均與實施例1相同。 實施例4 除將實施例1中蝕刻液組成更換為10%六氟矽酸及3〇 %硫酸銨U 10 : 1 (體積比）混合之水溶液夕卜其餘實施條 件及步驟均與實施例1相同。 藉由掃瞄式電子顯微鏡(SEM),觀察實施例〗至4經浸 201222653 泡無電解鍍覆藥液步驟後之晶片表面，可發現沉積之貴金 屬粒子的直徑約10至100奈米；且藉SEM觀察經浸泡蝕 刻液步驟後之晶片表面及剖面，可發現晶圓表面形成有直 徑約70奈米至100奈米之微孔結構，而微孔的深度約達1 微米（micrometer)至10微米。 如上所述，本發明完全符合專利三要件：新穎性、進 步性和產業上的可利用性。以新穎性和進步性而言，本發 明藉由提供有別於先前技術之化學蝕刻液成分，可提供使 用者於進行蝕刻時更多的選擇，進而達到降低太陽能電池 的生產成本之目的；就產業上的可利用性而言，利用本發 明所衍生的產品，當可充分滿足目前市場的需求。 本發明在上文中已以較佳實施例揭露，然熟習本項技 術者應理解的是，該實施例僅用於描繪本發明，而不應解 讀為限制本發明之範圍。應注意的是，舉凡與該實施例等 效之變化與置換，均應設為涵蓋於本發明之範疇内。因此， 本發明之保護範圍當以下文之申請專利範圍所界定者為 準。 【圖式簡單說明】 第1圖與第2圖係本發明各較佳具體實施例的剖面示 意圖。 【主要元件符號說明】 1 秒晶片基板 15 201222653 2 貴金屬粒子An aqueous solution of Mole/L silver nitrate (AgN03) and 1.0 Mole/L sodium hydroxide (NaOH). Residual solution: 10% ammonium fluoride and 30% perchloric acid in an aqueous solution of 1 〇 : 1 (volume ratio). The wafer was immersed in the cleaning solution for 1 minute to wash the wafer. Next, the wafer is immersed in an electroless plating solution for about 2 minutes to deposit silver ions on the surface of the wafer. Next, the wafer on which the silver particles are deposited is immersed in the etching solution for 1 minute to 30 minutes. [Example 2] The conditions and procedures were the same as in Example 1 except that the composition of the etching solution in Example 1 was changed to an aqueous solution in which 2% by weight of ammonium hydrogen fluoride and 3 % by weight of ammonium nitrate were mixed in a ratio of 10:1 (volume ratio). Example 3 Except that the composition of the etching solution in Example 1 was changed to an aqueous solution in which 1% by weight of tetrafluoroboric acid and 3% by% of periodic acid were mixed in a volume ratio of 10.1 (volume ratio), the remaining conditions and steps were the same as in Example 1. the same. Example 4 except that the composition of the etching solution in Example 1 was changed to 10% hexafluoroantimonic acid and 3% by weight ammonium sulfate U 10 : 1 (volume ratio) mixed aqueous solution, the remaining conditions and steps were the same as in Example 1. . By scanning electron microscopy (SEM), observing the surface of the wafer after the steps of the electroless plating solution of the examples 22 to 4, 201222653, the deposited precious metal particles can be found to have a diameter of about 10 to 100 nm; SEM observation of the surface and cross section of the wafer after the immersion etching step, it can be found that the surface of the wafer is formed with a microporous structure having a diameter of about 70 nm to 100 nm, and the depth of the micropores is about 1 micrometer to 10 micrometers. . As described above, the present invention fully complies with the three requirements of the patent: novelty, advancement, and industrial applicability. In terms of novelty and advancement, the present invention provides a user with more choices in etching by providing a chemical etching liquid component different from the prior art, thereby achieving the purpose of reducing the production cost of the solar cell; In terms of industrial applicability, products derived from the present invention can sufficiently satisfy the needs of the current market. The invention has been described above in terms of the preferred embodiments thereof, and it is understood by those skilled in the art that the present invention is not intended to limit the scope of the invention. It should be noted that variations and permutations that are equivalent to the embodiments are intended to be within the scope of the present invention. Therefore, the scope of the invention is defined by the scope of the following claims. BRIEF DESCRIPTION OF THE DRAWINGS Figs. 1 and 2 are cross-sectional views of preferred embodiments of the present invention. [Main component symbol description] 1 second wafer substrate 15 201222653 2 Precious metal particles