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三達編號：TW2861PA 九、發明說明： 【發明所屬之技術領域】 本發明是有關於一種清洗方法，特別是有關於一種濕 ' 蝕刻後之清洗方法及應用其之薄膜電晶體之形成方法。 【先前技術】 . 由於平面顯示器產業的快速進步，各家廠商對於產品 技術的改良莫不卯足全力。其中製程方法的改進，對於元 件效能的改良及生產效率的提升更是有極大的影響。 對於平面顯示器而言，顯示面板是最重要的元件，而 其中薄膜電晶體（thin film transistor，TFT)的形成是 控制平面顯示器電性品質最重要的步驟之一。尤其是金屬 層所形成的閘極、源極及没極，更是直接影響電性的良窳。 傳統TFT液晶顯示陣列製程，主要包括材料沈積、曝 光、顯影、蝕刻等步驟。其中在蝕刻步驟中，為求取較大 的生產效率，便採用濕蝕刻。但當蝕刻液中含有磷酸時， 因與金屬（例如銘）產生化學反應，會在元件（例如閘極、 源極或汲極）上產生結構鬆散的金屬氧化物（例如氧化 銘）。可能的化學反應式如下： 4Al + 6HN〇3—AL2O3+H2O+6NO2 Al2〇3+H3P〇4->2AlP〇4+3H2〇 由於此金屬氧化物表面不平整且大多具有離子捕捉 能力，在TFT作動時會造成漏電流，尤其當驅動電壓較小 時會造成源極、汲極之間導通的起始電壓增加。如此 5 -1273713达达编号号: TW2861PA IX. Description of the Invention: [Technical Field] The present invention relates to a cleaning method, and more particularly to a method of cleaning after wet etching and a method of forming a thin film transistor using the same. [Prior Art] Due to the rapid advancement of the flat panel display industry, various manufacturers have made great efforts to improve product technology. Among them, the improvement of the process method has a great impact on the improvement of component performance and the improvement of production efficiency. For flat panel displays, the display panel is the most important component, and the formation of thin film transistors (TFTs) is one of the most important steps in controlling the electrical quality of flat panel displays. In particular, the gate, source and immersion formed by the metal layer directly affect the electrical properties. The conventional TFT liquid crystal display array process mainly includes steps of material deposition, exposure, development, etching, and the like. Among them, in the etching step, in order to obtain a large production efficiency, wet etching is employed. However, when the etchant contains phosphoric acid, a chemical reaction with the metal (such as ing) produces a loose metal oxide (such as oxidized metal) on the device (such as a gate, source or drain). The possible chemical reaction formula is as follows: 4Al + 6HN〇3—AL2O3+H2O+6NO2 Al2〇3+H3P〇4->2AlP〇4+3H2〇 Due to the uneven surface of the metal oxide and most of the ion trapping ability, Leakage current is caused when the TFT is activated, especially when the driving voltage is small, which causes an increase in the initial voltage between the source and the drain. So 5 -1273713
^ 三達編號：TW2861PA 來，造成不同驅動電壓下，閘極之電壓與源極、汲極之間 的導通電流之特性曲線產生差異，造成整體顯示面板的穩 定性及可靠度降低。 【發明内容】 有鑑於此，本發明的目的就是在提供一種濕蝕刻後之 . 清洗方法及應用其之薄膜電晶體之形成方法，在濕蝕刻金 屬層之後加入一清洗製程，去除元件上的金屬氧化物。由 於去除了具有離子捕捉能力及結構鬆散的金屬氧化物，因 此本發明可以有效減少漏電流，使不同驅動電壓下之閘極 電壓與導通電流的特性曲線趨於^致5提南顯不面板的穩 定性與可靠度。 根據本發明的目的，提出一種清洗方法。首先，提供 基板，基板包括一金屬層；接著，濕姓刻金屬層使得金屬 層上具有一氧化物；然後，以一清洗液去除金屬層上之氧 化物。 根據本發明的另一目的，提出薄膜電晶體之形成方 法。首先，形成第一金屬層於基板上；接著，濕蝕刻第一 金屬層，以形成閘極，閘極上具有第一氧化物；然後，形 成絕緣層於閘極上；接著，形成通道層於絕緣層上；然後， 形成第二金屬層於通道層上；接著，蝕刻第二金屬層，以 形成源極及汲極，源極及汲極之至少一個上具有第二氧化 物；然後，以清洗液去除第一氧化物及第二氧化物之至少 1273713 ί達編號：TW2861PA 【實施方式】 .請同時參照以圖，其繪示本發明的_種薄膜電晶體 之形成方法流程圖。並請同時參照第2A〜2K圖，1洽示 軸本發㈣薄膜電晶體之流㈣面圖。首先，如步驟曰n 及第2A圖所示，形成第一金屬層12〇於基板1丨〇上。 接著，如步驟12及第2B圖所示，濕蝕刻第一金屬層 】2〇，以形成閘極122，閘極122上具有第一氧化物123曰。 本實施例中由於第一金屬層120的材料中包含鋁、銦或 鈦，因此經過含有磷酸的蝕刻液浸泡後，在閘極122表面 產生之第一氧化物123(例如氧化鋁）等較為鬆散的結構。 主然後，如步驟13及第2C圖所示，以喷灑或浸泡於一 清洗液，例如氫氟酸（HF)水溶液的方式，去除閘極122上 的第氧化物123。氫氟酸水溶液之重量百分比濃度約為 1至1之間’或疋〇 · 1至〇 · 5之間，而整個以氫氟酸: 除氧化物123的過程大約歷時1〇秒至30秒之間。 接著，如步驟14所示，以乾淨的水，例如去離子水 去除氫氟酸水溶液，以防止氫氟酸進一步侵蝕而損壞開極 122。 、 ^ 然後’如步驟15及第2D圖所示，形成絕緣層1覆 蓋於閘極122之上。 -1273713^ Sanda number: TW2861PA, resulting in a difference in the characteristic curve between the voltage of the gate and the conduction current between the source and the drain under different driving voltages, resulting in a decrease in the stability and reliability of the overall display panel. SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a method for forming a thin film transistor after wet etching, and a method for forming a thin film transistor by using a cleaning process after wet etching the metal layer to remove metal on the device. Oxide. Since the metal oxide having the ion capturing capability and the loose structure is removed, the present invention can effectively reduce the leakage current, and the characteristic curve of the gate voltage and the conduction current under different driving voltages tends to be 5 Stability and reliability. According to the purpose of the present invention, a cleaning method is proposed. First, a substrate is provided, the substrate comprising a metal layer; then, the wet metal layer is patterned to have an oxide on the metal layer; then, the oxide on the metal layer is removed by a cleaning solution. According to another object of the present invention, a method of forming a thin film transistor is proposed. First, a first metal layer is formed on the substrate; then, the first metal layer is wet-etched to form a gate having a first oxide thereon; then, an insulating layer is formed on the gate; then, a channel layer is formed on the insulating layer Forming a second metal layer on the channel layer; then, etching the second metal layer to form a source and a drain, and having a second oxide on at least one of the source and the drain; and then, cleaning the solution At least 1273713 of the first oxide and the second oxide are removed. 达达达: TW2861PA. [Embodiment] Referring to the drawings, a flow chart of a method for forming a thin film transistor of the present invention is shown. Please also refer to the 2A~2K diagram at the same time, 1 for the shaft (4) of the film transistor (4). First, as shown in steps 曰n and 2A, the first metal layer 12 is formed on the substrate 1A. Next, as shown in steps 12 and 2B, the first metal layer is wet-etched to form a gate 122 having a first oxide 123?. In the present embodiment, since the material of the first metal layer 120 contains aluminum, indium or titanium, the first oxide 123 (for example, alumina) generated on the surface of the gate 122 is relatively loose after being immersed in the etching solution containing phosphoric acid. Structure. Mainly, as shown in steps 13 and 2C, the oxide 123 on the gate 122 is removed by spraying or immersing in a cleaning solution such as an aqueous solution of hydrofluoric acid (HF). The concentration of the aqueous solution of hydrofluoric acid is between about 1 and 1 ' or between 疋〇·1 and 〇·5, and the whole is hydrofluoric acid: the process of removing oxide 123 takes about 1 sec to 30 sec. between. Next, as shown in step 14, the hydrofluoric acid aqueous solution is removed with clean water, such as deionized water, to prevent further attack of hydrofluoric acid and damage the open electrode 122. Then, as shown in steps 15 and 2D, the insulating layer 1 is formed over the gate 122. -1273713
二達編5虎· TW2861PA 不，形成一半導體層 之材料可包括非晶矽 接著，如步驟16及第2E圖所 14〇於絕緣層13〇上。半導體層140 或多晶每^。 15〇^H步,驟17及第2F圖所示，形絲刻終止層 於+¥體層140上，並將半導體層14〇 韻刻之步驟後定義主動層驰。 』、先，“、 接著，如步驟18及第2G圖所示，形成N+半 _或稱之為N+層）於主動層刚a及㈣終止層15〇上曰。 ί發明並不侷限於形成晴體層，例如P+半導體層也可 患用’視所需薄膜電晶體型態而定。 然後，如步驟19及第2Η圖所示，形成一第二 no於r半導體層160上。 弟盈屬層 接著，如步驟2〇及第21圖所示，濕蝕刻第二金屬層 —、，开乂成源極172及〉及極174，並钱刻半導體層16〇 以定義完成圖案化N+半導體層施。而源極172及没極 Π4之間的相對内側表面上，同樣因祕刻製程而 二氧化物175。 尸/後，如步驟21及第2 J圖所示，同樣以喷灑或浸泡 於氫氟酸水溶液之方式，以去除源極172及祕174上之 第二氧化物175。 紅 > 接著，如步驟22所示，同樣以乾淨的水洗去殘餘之 虱氟酸水溶液。 取後，如第2K圖所示，進一步形成保護層18〇覆蓋 絕緣層130、源極172、没極m及钱刻終止層15〇。保護 1273713Erda 5 Hu TW2861PA No, the material forming a semiconductor layer may include amorphous 矽 Next, as shown in steps 16 and 2E on the insulating layer 13A. The semiconductor layer 140 or polycrystalline each. 15 〇 ^ H step, step 17 and 2F, the shape of the wire is terminated on the +¥ body layer 140, and the step of the semiconductor layer 14 is engraved to define the active layer. 』, first, “, then, as shown in steps 18 and 2G, an N+semi_ or N+ layer is formed) on the active layer a and the (4) termination layer 15〇. The invention is not limited to formation. A fine layer, such as a P+ semiconductor layer, may also be subjected to a desired film transistor type. Then, as shown in steps 19 and 2, a second no is formed on the r semiconductor layer 160. Layers, as shown in steps 2 and 21, wet etching the second metal layer, opening the source 172 and the > and 174, and engraving the semiconductor layer 16 to define the patterned N+ semiconductor layer. On the opposite inner side surface between the source 172 and the electrodeless electrode 4, the dioxide 175 is also formed by the secret engraving process. The corpse/back, as shown in steps 21 and 2 J, is also sprayed or soaked. In the form of an aqueous solution of hydrofluoric acid, the second oxide 175 on the source 172 and the secret 174 is removed. Red > Next, as shown in step 22, the residual aqueous solution of hydrofluoric acid is also washed away with clean water. As shown in FIG. 2K, the protective layer 18 is further formed to cover the insulating layer 130, the source 172, the poleless m, and the money engraved 15〇 stop layer protective 1,273,713
三達編號：TW2861PA 層180上具有一貫孔185，並進一步在保護層180上形成 晝素電極層190，使晝素電極層190透過貫孔185與汲極 174耦接。至此薄膜電晶體100便告完成。 * 然而，本發明所屬之技術領域具有通常知識者，可知 本發明之技術不限於此。例如，本實施例雖以氳氟酸水溶 液做為清洗液以去除氧化物，但是也可以採用硝酸（HNOs) 水溶液或碗酸（H3PO4)水溶液做為清洗液。只要在金屬層於 蝕刻完成後加入一清洗製程，以一清洗液去除金屬層上與 姓刻液作用所產生之氧化物，皆屬於本發明之範圍。而本 實施例雖以具有蝕刻終止層150之薄膜電晶體100說明， 然而亦可用於不具蝕刻終止層薄膜電晶體。 本發明上述實施例所揭露之濕蝕刻後之清洗方法及 應用其之薄膜電晶體之形成方法，係在金屬層經濕蝕刻後 加入一清洗步驟，以去除所定義之結構上之鬆散的氧化 物。使得定義完成之元件於導通時不會產生漏電流，提供 丨具有穩定電性的薄膜電晶體。 綜上所述，雖然本發明已以一較佳實施例揭露如上， 然其並非用以限定本發明。本發明所屬技術領域中具有通 常知識者，在不脫離本發明之精神和範圍内，當可作各種 之更動與潤飾。因此，本發明之保護範圍當視後附之申請 專利範圍所界定者為準。 9 Ϊ273713Sanda number: TW2861PA layer 180 has a uniform hole 185, and further forms a halogen electrode layer 190 on the protective layer 180, so that the halogen electrode layer 190 is coupled to the drain 174 through the through hole 185. At this point, the thin film transistor 100 is completed. * However, the technical field to which the present invention pertains is generally known, and the technology of the present invention is not limited thereto. For example, in the present embodiment, an aqueous solution of hydrofluoric acid is used as a cleaning liquid to remove oxides, but an aqueous solution of nitric acid (HNOs) or an aqueous solution of a bowl of acid (H3PO4) may be used as the cleaning liquid. It is within the scope of the present invention to add a cleaning process to the metal layer after the etching is completed, and to remove the oxide generated by the action of the etchant on the metal layer with a cleaning liquid. While the present embodiment is illustrated by a thin film transistor 100 having an etch stop layer 150, it can also be used for a thin film transistor without an etch stop layer. The method for cleaning after wet etching disclosed in the above embodiments of the present invention and the method for forming the thin film transistor thereof are characterized in that after the metal layer is wet-etched, a cleaning step is added to remove loose oxides on the defined structure. . The defined component does not generate leakage current when it is turned on, and provides a thin film transistor with stable electrical properties. In view of the above, the present invention has been disclosed in a preferred embodiment, and is not intended to limit the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims. 9 Ϊ273713
三達編號：TW2861PA 【圖式簡單說明】 第1圖繪示本發明的一種薄膜電晶體之形成方法流 程圖；以及 - 第2A〜2K圖繪示形成本發明的薄膜電晶體之流程剖 . 面圖。 【主要元件符號說明】 110 :基板 120 :第一金屬層 122 :閘極 123 :第一氧化物 130 :絕緣層 140 :半導體層 140a :主動層 150 :蝕刻終止層 160 : N+半導體層 160a :圖案化N+半導體層 170 :第二金屬層 172 :源極 174 :没極 175 :第二氧化物 180 :保護層 185 :貫孔 190 :晝素電極層Sanda number: TW2861PA [Simplified description of the drawings] Fig. 1 is a flow chart showing a method of forming a thin film transistor of the present invention; and - Figs. 2A to 2K are diagrams showing the flow of forming a thin film transistor of the present invention. Figure. [Main component symbol description] 110: substrate 120: first metal layer 122: gate 123: first oxide 130: insulating layer 140: semiconductor layer 140a: active layer 150: etch stop layer 160: N+ semiconductor layer 160a: pattern N+ semiconductor layer 170: second metal layer 172: source 174: gate 175: second oxide 180: protective layer 185: through hole 190: halogen electrode layer