A7 B7 經濟部中央標準局貝工消費合作社印敢 λ發明説明（/ ) 本發明是有關於一種製作薄膜電晶體（Thin Film Transistor ; TFT)的方法，且特別是有關一種製作薄膜電 晶體鋁閘極的方法。 非晶矽薄膜電晶體常被用來當作主動式矩陣液晶顯 不器仏丨办丨己Crystal Display ; LCD)的切換元件，這是 因舄非晶矽具有可在低溫下沉積，生產成本低，漏電流小 及適合於大面積製作等優點，但是由於一般非晶矽薄膜電 晶體的鋁閘極在高溫時會產生突起（Hillock)的現象，導 致非晶矽薄膜電晶體的特性變差。因此，如何抑制鋁閘極 的突起現象是一個重要的課題。. 鋁閘極突起的現象主要是因爲鋁閘極與基板絕緣層的 熱膨脹係數差異太大，且鋁的熔點太低，容易發生空洞擴 散（Vacancy Diffusion)的情.形。當溫度上升時，由於錦 閘極與基板絕緣層會產生不同的應力，而且鋁閘極內部的 晶格空洞會擴散，以釋放鋁閘極內部的應力，因此容易在 銘鬧極內部的晶粒介面（Grain Boundary)發生突起的現 象。一般抑制鋁突起的現象有下列幾種方式： 第一種方式爲在鋁閘極上沉積一層金屬鎢或鈦，如此 雖然可以在垂直方向抑制鋁閘極突起的現象，但卻會迫使 铝閘極向側邊突出，在元件尺寸以及間距都逐漸縮小的情 況下，會導致鋁閘極與其他相鄰元件相接而產生短路的現 象。 另一種方式爲在鋁閘極內加入一些元素，並且使得這 些加入的元素的量超過金屬鋁的最大溶解度，藉此在晶界 3 本紙張尺度適用t國國家標準{ CNS ) A4規格（210X297公翁） (請先閲讀背面之注意事項再填寫本頁) -裝· 訂A7 B7 Yingan λ Description of the Shellfish Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs (/) The present invention relates to a method for manufacturing thin film transistors (TFTs), and more particularly to a method for manufacturing thin-film transistor aluminum gates Extreme method. Amorphous silicon thin film transistor is often used as an active matrix liquid crystal display (Crystal Display; LCD) switching element. This is because the amorphous silicon can be deposited at low temperatures, and the production cost is low. , Small leakage current and suitable for large-area production, but due to the aluminum gate of the ordinary amorphous silicon thin film transistor at high temperature will produce a bump (Hillock) phenomenon, resulting in poor characteristics of the amorphous silicon thin film transistor. Therefore, how to suppress the protrusion of the aluminum gate is an important issue. The phenomenon of aluminum gate protrusion is mainly because the difference between the thermal expansion coefficient of the aluminum gate and the substrate insulation layer is too large, and the melting point of aluminum is too low, which is prone to Vacancy Diffusion. When the temperature rises, because the gate and the substrate insulation layer will produce different stresses, and the lattice voids inside the aluminum gate will diffuse to release the stress inside the aluminum gate, it is easy to crystallize inside the gate. The interface (Grain Boundary) is protruding. Generally, there are several ways to suppress the phenomenon of aluminum protrusion: The first method is to deposit a layer of metal tungsten or titanium on the aluminum gate. Although this can suppress the phenomenon of aluminum gate protrusion in the vertical direction, it will force the aluminum gate to The side edges protrude. When the component size and pitch are gradually reduced, the aluminum gate will be connected to other adjacent components and a short circuit will occur. Another way is to add some elements in the aluminum gate, and make the amount of these elements exceed the maximum solubility of metal aluminum, thereby applying the national standard {CNS) A4 specification (210X297) Weng) (Please read the notes on the back before filling out this page)
.「M 經濟部中央標準局貝工消費合作社印製 4257t^.|〇Q(g〇g^ A7 B7 五、發明説明（2) (Grain Boundary)產生多餘的析出物，由於這些析出物能 夠防止晶格空洞擴散，所以可以防止鋁閘極突起的現象。 但是這種方式只能降低鋁閘極突起的現象，並不能有效的 抑制鋁閘極的突起，而且這些析出物在鋁閘極由高溫快速 降至低溫時，較易造成析出物跑入閘極介電層內，使得閘 極介電層的品質變差的情形。 第三種方式則是在鋁閘極內加入矽元素，完成後再於 鋁閘極的表面上沉積一層金屬鈦，，如此雖然可以防止鋁閘 極突起的現象，但是由於加入矽元素會使鋁閘極的阻値過 大，將導致元件的操作速度變慢。 本發明提供一種製作薄膜電晶體鋁閘極的方法，避免 在製作薄膜電晶體時，鋁閘極的表面產生突起的現象。其 方法爲在絕緣基板上定義出鋁閘極區域之後，將具有鋁閘 極的絕緣基板浸入含有反應性低於鋁之貴重金屬的貴重 金屬溶液中，使鋁閘極與貴重金屬發生置換反應，在鋁閘 極的表面上形成一層保護層，將鋁閘極表面以及側邊完全 包圍住。之後再形成源極/汲極導電層以及包括閘極介電 層、通道非晶矽薄膜與高濃度非晶矽薄膜的覆蓋層，以完 成薄膜電晶體的製程。 由於保護層將鋁閘極的表面以及側邊完全包鼠住’所 以可以有效抑制鋁鬧.極發生突起的現象，也不會造成經由 側邊與相鄰元件短路的狀況，並且仍然可以保持鋁閘極低 阻値的特性。由於本發明的方法只需在定義鋁閘極之後’ 將鋁閘極與絕緣基板浸入貴重金屬溶液中形成保護層’即 4 ^^尺度適肉中國國家標準（<^^)八4規格（2!0父297公釐> ^^^1. I - — —rtit - .^1 (請先聞讀背面之注意事項再填寫本頁) -訂 ，摄 經減部屮决榡卑局员二消资合作社印" 4257iwf,do 41^0 383 A7 __- _B7___ 五、發明説明（彡） 可達到保護鋁閘極的目的，因此具有製程簡單與成本低的 優點。 爲讓本發明之上述和其他目的、特徵、和優點能更明 顯易懂，下文特舉一較佳實施例，並配合所附圖式，作詳 細說明如下。 圖示之簡單說明： 第1A圖至第1E圖繪示依照本發明之一較佳實施例製 作薄膜電晶體鋁閘極的剖面流程圖。 圖示標記說明： 100 絕緣基板 102 鋁閘極 104 保護層 106 閘極介電層 108 通道非晶矽薄膜 110 高濃度非晶矽薄膜 112 覆蓋層 114 源極/汲極導電層 實施例 '請參照第1A圖，在一個絕緣基板100上形成一個鋁 閘極102。形成鋁閘極102的方法比如爲先在絕緣基板100 上形成一層鋁金屬層（未繪示於圖中），再以微影蝕刻的方 式定義出鋁閘極102。 接著，請參照第1B圖，將絕緣基板1〇〇與鋁閘極1〇2 浸入含有反應性低於鋁之貴重金屬的貴重金屬溶液’使得 5 本紙張尺度ϋ中國囤家掠哗（巧S)A4規格（ 210X297公ί) (請先閱讀背面之注意事項再填寫本頁) 裝. ¥ 42 5 7twf.d^i-〇0383 A7 B7 五、發明説明（> ) 鋁閘極102與貴重金屬發生置換反應，在鋁閘極102的表 面與側壁形成一層保護層104，將鋁閘極102的表面以及 側壁包圍起來。形成保護層104的作用在於使鋁閘極102 與外界隔絕，以抑制在後續的製程中鋁閘極102產生突起 的現象。貴重金屬溶液比如爲含有硫酸銅（CuSOO、硝酸銀 (AgNCb)或是氯化鈀（PdCh)的溶液。形成保護層104的方 法比如爲在酸性的環境中，溫度爲攝氏20度至50度之 間，將該絕緣基板浸入貴重金屬濃度約爲0.05至0.5莫 耳濃度之該貴重金屬溶液大約3至10分鐘。貴重金屬溶 液中的銅、銀或是鈀皆爲反應性較鋁低的貴重金屬，與鋁 閘極102的金屬鋁發生置換反應後，會在鋁閘極102的表 面形成一層保護層104，藉以保護鋁閘極102，以避免在 後續製程中發生鋁閘極102突起的現象。 之後，請參照第1C圖，在絕緣基板100以及鋁閘極 102上依序形成閘極介電層106、通道非晶矽薄膜108以 及高濃度非晶矽薄膜110,之後再以微影成像與蝕刻的方 式移除部分的閘極介電層106、通道非晶矽薄膜108以及 高濃度非晶矽薄膜110，以定義出覆蓋層112。其中，閘 極介電層的材質比如爲氮化矽。 _接著，請參照第1D圖，在覆蓋層110上形成源極/ 汲極導電層114,其中源極/汲極導電層114覆蓋住高濃度 非晶矽薄膜108的側邊以及部分上表^。形成此源極/汲 極導電層114的方法比如爲先沉積一層與覆蓋層112共 形，且材質比如爲鋁的金屬層（未繪示於圖中），再利用微 6 本紙張尺度冗用中國围家棉冷（（'NS ) Λ4規格（210X297公釐） (請先閱讀背面之注意事項再填寫本頁) -裝.. "M Printed by the Shell Standard Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs 4257t ^. | 〇Q (g〇g ^ A7 B7 V. Description of the invention (2) (Grain Boundary) produces extra precipitates, because these precipitates can prevent Lattice voids are diffused, so that the phenomenon of aluminum gate protrusion can be prevented. However, this method can only reduce the phenomenon of aluminum gate protrusion, and cannot effectively suppress the aluminum gate protrusion, and these precipitates in the aluminum gate are affected by high temperature. When the temperature drops rapidly, it is easier to cause precipitates to run into the gate dielectric layer, which will cause the quality of the gate dielectric layer to deteriorate. The third method is to add silicon element to the aluminum gate. A layer of metal titanium is deposited on the surface of the aluminum gate. Although the phenomenon of aluminum gate protrusion can be prevented, the addition of silicon element will cause the resistance of the aluminum gate to be too large, which will cause the operation speed of the component to slow. The invention provides a method for making a thin-film transistor aluminum gate, which avoids the phenomenon of protrusions on the surface of the aluminum gate when making a thin-film transistor. The method is to define an aluminum gate region on an insulating substrate, and then An insulating substrate with an aluminum gate is immersed in a precious metal solution containing a precious metal that is less reactive than aluminum, so that the aluminum gate and the precious metal undergo a substitution reaction, and a protective layer is formed on the surface of the aluminum gate. The surface and sides are completely enclosed. Then, a source / drain conductive layer and a cover layer including a gate dielectric layer, a channel amorphous silicon film, and a high-concentration amorphous silicon film are formed to complete the thin film transistor process. Because the protective layer completely covers the surface and sides of the aluminum gate electrode, it can effectively suppress aluminum noise. The phenomenon of protrusion of the electrode can not cause a short circuit with adjacent components via the side edges, and it can still maintain aluminum. The characteristics of low resistance of the gate electrode. Because the method of the present invention only needs to 'immerse the aluminum gate electrode and the insulating substrate in a precious metal solution to form a protective layer' after defining the aluminum gate electrode, that is, the 4 ^^ scale is suitable for Chinese national standards ; ^^) 8 4 specifications (2! 0 father 297 mm > ^^^ 1. I-— —rtit-. ^ 1 (please read the precautions on the back before filling out this page)-order, photo by Reduction of Ministry of Justice Zuosha Seal " 4257iwf, do 41 ^ 0 383 A7 __- _B7___ 5. Explanation of the Invention (彡) The purpose of protecting the aluminum gate can be achieved, so it has the advantages of simple process and low cost. In order to make the above and other aspects of the present invention The purpose, features, and advantages can be more clearly understood, and a preferred embodiment is given below in conjunction with the accompanying drawings to make a detailed description as follows. A brief description of the figures: Figures 1A to 1E are shown in accordance with the present invention. One preferred embodiment of the invention is a cross-sectional flow chart of making a thin film transistor aluminum gate. The symbols indicate: 100 insulating substrate 102 aluminum gate 104 protective layer 106 gate dielectric layer 108 channel amorphous silicon film 110 Example of crystalline silicon film 112 cover layer 114 source / drain conductive layer 'Please refer to FIG. 1A, an aluminum gate 102 is formed on an insulating substrate 100. The method for forming the aluminum gate 102 is, for example, firstly forming an aluminum metal layer (not shown in the figure) on the insulating substrate 100, and then defining the aluminum gate 102 by means of lithographic etching. Next, referring to FIG. 1B, the insulating substrate 100 and the aluminum gate electrode 102 were immersed in a precious metal solution containing a precious metal less reactive than aluminum. ) A4 specification (210X297), (please read the precautions on the back before filling this page). Pack. ¥ 42 5 7twf.d ^ i-〇0383 A7 B7 V. Description of the invention () Aluminum gate 102 and precious A metal substitution reaction occurs, and a protective layer 104 is formed on the surface and the side wall of the aluminum gate 102 to surround the surface and the side wall of the aluminum gate 102. The protective layer 104 is formed to isolate the aluminum gate 102 from the outside, so as to suppress the phenomenon that the aluminum gate 102 is protruded in a subsequent process. The precious metal solution is, for example, a solution containing copper sulfate (CuSOO, silver nitrate (AgNCb), or palladium chloride (PdCh). The method for forming the protective layer 104 is, for example, in an acidic environment at a temperature between 20 ° C and 50 ° C The insulating substrate is immersed in the precious metal solution having a precious metal concentration of about 0.05 to 0.5 mol for about 3 to 10 minutes. Copper, silver or palladium in the precious metal solution are all precious metals having a lower reactivity than aluminum. After the substitution reaction with the metal aluminum of the aluminum gate 102, a protective layer 104 is formed on the surface of the aluminum gate 102, thereby protecting the aluminum gate 102 to avoid the protrusion of the aluminum gate 102 in subsequent processes. Referring to FIG. 1C, a gate dielectric layer 106, a channel amorphous silicon film 108, and a high-concentration amorphous silicon film 110 are sequentially formed on the insulating substrate 100 and the aluminum gate 102, and then lithographically imaged and etched. The gate dielectric layer 106, the channel amorphous silicon film 108, and the high-concentration amorphous silicon film 110 are partially removed to define the cover layer 112. The material of the gate dielectric layer is, for example, silicon nitride. _then, Referring to FIG. 1D, a source / drain conductive layer 114 is formed on the cover layer 110, wherein the source / drain conductive layer 114 covers the side and a part of the high-concentration amorphous silicon film 108. The source is formed. The method of the electrode / drain conductive layer 114 is, for example, firstly depositing a metal layer conforming to the cover layer 112, and the material is aluminum (not shown in the figure). Cotton cold (('NS) Λ4 specifications (210X297 mm) (Please read the precautions on the back before filling out this page)-Packing.
、1T 線 經满部中央摞準局Μ.Τ.消资合作社印來 經濟部中央榡準局6J.消处合作社印？水 410383 4257lwi'.doc/00 6 A7 _B7___ 五、發明説明（ 影成像與蝕刻方式定義出源極/汲極導電層114。其中’源 極/汲極導電層114暴露出部分的高濃度非晶矽薄膜108。 請參照第1E圖’移除高濃度非晶矽薄膜108暴露出 來的部分，完成薄膜電晶體的製程。移除部分高濃度非晶 矽薄膜1(38的方法比如爲以源極/汲極導電層爲蝕刻 罩幕，進行非等向性蝕刻’移除未被源極/汲極導電層114 覆蓋的高濃度非晶矽薄膜1〇8 ° 本發明的特徵爲在絕緣基板上定義出鋁閘極之後’以 含有銅、銀或是鈀等反應性較鋁低之貴重金屬的貴重金屬 溶液浸泡具有鋁閘極的絕緣基板，使得鋁閘極的表面與側 壁形成一層保護層，如此一來’鋁閘極就不會因爲與絕緣 基板的熱膨脹係數差異太大以及因爲晶格空洞擴散釋放 應力而發生突起的現象，同時鋁閘極的側邊也不會與相鄰 元件發生短路的問題，並且可以維持鋁閘極低阻値的特 性。 由於本發明的方法所增加的薄膜電晶體製程步驟只有 在定義出鋁閘極之後先以貴重金屬溶液浸泡，之後就可以 進行形成覆蓋層以及源極/汲極導電層等後續的製程，因 此本發明的方法具有製程簡單的優點，也因其製程步驟簡 單'.，製程成本也相對的降低，因此是一種相當實用的薄膜 電晶體鋁閘極製程方法。 < .雖然本發明已以一較佳實施例揭露&上，然其並非用 以限定本發明，任何熟習此技藝者，在不脫離本發明之精 神和範圍內，當可作些許之更動與潤飾，因此本發明之保 7 本紙冗尺政中國囤家標？？_( CNS } Λ4現格（2)0X297公釐) " ' (讀先閲讀背面之注意事項再填寫本頁) 裝. 訂 經滅部中夾標卑历β工消处合作社印架 410S83 4257twf.d〇c/00 6 A 7 B7 五、發明説明（6 ) 護範圍當視後附之申請專利範圍所界定者爲準。 .(請先閱讀背面之注意事項再填寫本頁) -裝. 丁 一線 本紙張尺度诚州中國S家標肀（（’NS) Λ4规格（210X297公釐）Line 1T printed by the Ministry of Economic Affairs Central Bureau of Commerce M.T. Consumer Cooperatives? Water 410383 4257lwi'.doc / 00 6 A7 _B7___ V. Description of the invention (The imaging / etching method defines the source / drain conductive layer 114. Among them, the source / drain conductive layer 114 exposes a portion of the high-concentration amorphous Silicon film 108. Please refer to FIG. 1E 'Remove the exposed part of the high-concentration amorphous silicon film 108 to complete the thin film transistor process. The method of removing a part of the high-concentration amorphous silicon film 1 (38) is to use a source The / drain conductive layer is an etching mask, and anisotropic etching is performed to remove the high-concentration amorphous silicon thin film not covered by the source / drain conductive layer 114. The present invention is characterized in that it is on an insulating substrate. After the aluminum gate is defined, the insulating substrate with the aluminum gate is immersed in a precious metal solution containing precious metals with lower reactivity than aluminum, such as copper, silver or palladium, so that the surface of the aluminum gate and the side wall form a protective layer. In this way, the aluminum gate will not protrude due to the difference in thermal expansion coefficient from the insulating substrate and the stress released by the diffusion of the lattice cavity. At the same time, the sides of the aluminum gate will not short-circuit with adjacent components. Ask And can maintain the characteristics of low resistance of the aluminum gate. Because the thin film transistor process step added by the method of the present invention is only after the aluminum gate is defined, it is first immersed in a precious metal solution, and then the cover layer and the source can be formed. Subsequent processes such as electrode / drain conductive layers, the method of the present invention has the advantage of simple process, and also because of the simple process steps. ', The process cost is relatively reduced, so it is a quite practical thin film transistor aluminum gate Process method < Although the present invention has been disclosed in a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make it without departing from the spirit and scope of the present invention. Some changes and retouching, so the guarantee of the present invention 7 This paper is a redundant rule of the Chinese storehouse? _ (CNS} Λ4 is now (2) 0X297 mm) " '(Read the precautions on the back before filling in this Page) Assembled. Orders printed in the Ministry of Destruction of the Ministry of Economics and Social Affairs Office Cooperatives 410S83 4257twf.d〇c / 00 6 A 7 B7 5. Description of the invention (6) The scope of protection shall be attached as the scope of the patent application Definer Associate (Please read the notes on the back of this page to fill out) -. This paper loaded line Ding Cheng-scale Chinese state S standard home Nie (( 'NS) Λ4 size (210X297 mm).