透明金屬氧化物膜之反應性磁控濺鍍的方法及裝置Method and device for reactive magnetron sputtering of transparent metal oxide film
本發明涉及一種利用反應性磁控濺鍍在基板上沉積出透明金屬氧化物膜的方法。尤其是涉及沉積出TCO層(透明導電氧化物)的方法及裝置。
The present invention relates to a method of depositing a transparent metal oxide film on a substrate by reactive magnetron sputtering. In particular, it relates to a method and apparatus for depositing a TCO layer (transparent conductive oxide).
磁控濺鍍是在待鍍膜的基板及磁控管(包括一個作為電極的標靶及一個磁系統)之間充滿適當之過程氣體的真空空間中點燃電漿，使電漿的正電荷透過濺射效應侵蝕標靶表面的外層。可以在有反應性氣體存在或是沒有反應性氣體存在的情況下濺鍍金屬，例如在有反應性氣體存在的情況下濺鍍金屬，可以在位於標靶之侵蝕表面的對面的基板上沉積出氧化物或氮化物。以類似的方式也可以用其他的材料組合作為標靶材料進行濺鍍。
為了有利於電漿的形成，以及加快離子轟擊標靶表面的速度，在標靶背對電漿的那一個面上設有一個磁系統，其中這個磁系統具有多個局部交錯極性且相鄰並排的磁鐵。這種用於磁控濺鍍的磁系統通常是由第一極性的一個中央極靴構成，並從兩邊以規律的方式將相反極性的極靴圍住，因此第二極靴以跑道狀的方式將第一極靴環繞住。由於環形的隧道狀磁場的關係，標靶材料在兩個磁極之間的間隙，也就是磁力線以平行於標靶表面的方式經過的區域，受到大幅侵蝕，因此在這個區域形成一個封閉的跑道狀的濺射溝。這個濺射溝也稱為跑道。磁性導引的封閉的電漿環的局部變化與標靶材料的侵蝕有相關性。
已知的標靶是平面標靶及管狀標靶，在放置時，此種標靶的軸向邊與基板通過加速器的運送方向垂直。在標靶連接磁系統之後，視標靶的形狀而定，稱為管狀磁控管或平面磁控管。
管狀磁控管可產生穩定的鍍膜過程及達到很高的標靶利用率，尤其是適於對大面積的基板進行鍍膜，或是應用於連續鍍膜。管狀磁控管包括一個可繞自身之縱軸轉動的圓柱形電極。
管狀磁控管的外殼面是由可濺鍍的標靶材料構成，其中標靶材料可以構成管狀標靶，這樣管狀陰極的圓柱體就完全是由要濺鍍的材料構成，管狀陰極也可以是由鍍有待鍍膜之材料的承載管構成。不論是採用何種構造方式，通常稱之為管狀標靶或管狀標靶。
在管狀標靶的內部設置一個如前面所述的磁系統，這個磁系統的範圍延伸到管狀標靶的整個長度，因此會在管狀標靶的外殼面上形成跑道，且跑道平行於管狀標靶的縱軸延伸到管狀標靶的整個長度。管狀標靶可以相對於磁系統轉動，因此管狀標靶在鍍膜過程中可以轉動，而磁系統在鍍膜室中的定向則始終保持不變。透過管狀標靶在穩定磁場中的均勻轉動，整個圓柱形標靶表面會通過跑道範圍，並使標靶材料被均勻的侵蝕。
所使用的管狀磁控管是單一磁控管(RSM)或具有規律且同步的轉動方向的雙磁控管(RDM)。所謂單一管狀磁控管是指一個與相鄰管狀磁控管間隔相當大的距離、或是與相鄰管狀磁控管被遮擋板或隔板隔開的管狀磁控管，因而使該管狀磁控管的分佈特性不會與相鄰管狀磁控管的分佈特性相交。
在進行反應性濺鍍時，所使用的過程氣體是由一種憜性工作氣體(例如氬或氖)及一種反應性氣體(例如氧或氮)組成，因此沉積在基板上的鍍膜的成分會含有反應性氣體。工作氣體及反應性氣體是經由氣體輸送系統以隔開或混合的方式被輸入處理室。由於反應性濺鍍使用的標靶通常比較便宜，而且鍍膜率通常也比較高，因此已被證明為一種成本較低的濺鍍方法。
透明金屬氧化物膜可應用於許多不同的應用範圍，例如在光學鍍膜系統中作為介電膜，或是在薄膜太陽能電池的面接觸中作為導電膜。例如，用摻雜鋁的氧化鋅(ZnO:Al)薄膜作為CIGS太陽能電池的前接點。視應用目的而定，透明金屬氧化物膜的光學及電學特性主要是由濺鍍方法決定。
在許多情況下，同時具有很小的電阻及很高的透明性是非常重要的，尤其是作為太陽能電池的前接點。由於鍍膜方法的能量平衡或層堆疊中單一層的敏感性，使被證明為對光學及電學薄膜特性非常有利的基板溫度的最佳化源受到明顯的限制。在陶瓷過程中對薄膜特性的最佳電位的其他過程參數，例如壓力、功率及磁場強度，已被證實不利於電阻-透明性組合的改善。但一件已知的事實是，利用一個較大的標靶-基板-間距可以達到較佳的薄膜特性。使用不平衡的極靴也無法達到希望的結果。
此外，透明金屬氧化物的反應性濺鍍也無法在整個膜厚度都同時達到最佳的透明性及電阻。另外一點是，電漿中形成膜的粒子無法達到足夠的化學計量均勻性，這顯示於表面電阻的參數的不均勻性及所產生的膜的透明性的不均勻性。就這方面而言，相較於陶瓷管狀磁控管的非反應性或部分反應性濺鍍，反應性濺鍍(例如ZnO:Al)是比較不利的。
Magnetron sputtering is to ignite the plasma in a vacuum space filled with a suitable process gas between the substrate to be coated and the magnetron (including a target as an electrode and a magnetic system) to cause the positive charge of the plasma to pass through the splash. The ejection effect erodes the outer layer of the target surface. Metal can be sputtered in the presence or absence of a reactive gas, such as sputtering in the presence of a reactive gas, which can be deposited on the opposite substrate on the eroded surface of the target. Oxide or nitride. In a similar manner, other material combinations can also be used as the target material for sputtering.
In order to facilitate the formation of the plasma and accelerate the speed of the ion bombardment of the target surface, a magnetic system is provided on the surface of the target opposite to the plasma, wherein the magnetic system has a plurality of local staggered polarities and adjacent side by side Magnet. The magnetic system for magnetron sputtering is usually composed of a central pole piece of a first polarity and encloses the pole pieces of opposite polarity from both sides in a regular manner, so that the second pole piece is in the form of a racetrack. Surround the first pole piece. Due to the circular tunnel-like magnetic field, the gap between the two magnetic poles of the target material, that is, the region where the magnetic lines of force pass in parallel with the surface of the target, is greatly eroded, thus forming a closed racetrack in this region. Sputtering trench. This sputtering ditch is also known as the runway. The local variation of the magnetically guided closed plasma ring is related to the erosion of the target material.
Known targets are planar targets and tubular targets that, when placed, have axial sides that are perpendicular to the direction of transport of the substrate through the accelerator. After the target is connected to the magnetic system, depending on the shape of the target, it is called a tubular magnetron or a planar magnetron.
Tubular magnetrons produce a stable coating process and achieve high target utilization, especially for large-area substrates or for continuous coating. The tubular magnetron includes a cylindrical electrode that is rotatable about its longitudinal axis.
The outer surface of the tubular magnetron is composed of a sputterable target material, wherein the target material can constitute a tubular target, such that the cylindrical body of the tubular cathode is completely composed of a material to be sputtered, and the tubular cathode can also be It consists of a carrier tube coated with the material to be coated. Regardless of the configuration used, it is often referred to as a tubular target or a tubular target.
A magnetic system as described above is disposed inside the tubular target, the magnetic system extending over the entire length of the tubular target, thus forming a runway on the outer surface of the tubular target, and the runway is parallel to the tubular target The longitudinal axis extends to the entire length of the tubular target. The tubular target can be rotated relative to the magnetic system so that the tubular target can be rotated during the coating process while the orientation of the magnetic system in the coating chamber remains constant. Through the uniform rotation of the tubular target in a stable magnetic field, the entire cylindrical target surface will pass through the runway range and the target material will be uniformly eroded.
The tubular magnetron used is a single magnetron (RSM) or a dual magnetron (RDM) with a regular and synchronized direction of rotation. By single tubular magnetron is meant a tubular magnetron that is spaced a considerable distance from an adjacent tubular magnetron or that is separated from the adjacent tubular magnetron by a baffle or baffle, thus making the tubular magnet The distribution characteristics of the control tubes do not intersect the distribution characteristics of adjacent tubular magnetrons.
In the case of reactive sputtering, the process gas used consists of an inert working gas (such as argon or helium) and a reactive gas (such as oxygen or nitrogen), so the composition of the coating deposited on the substrate will contain Reactive gas. The working gas and the reactive gas are supplied to the processing chamber in a spaced or mixed manner via a gas delivery system. Since the targets used for reactive sputtering are generally cheaper and the coating rate is usually higher, it has proven to be a lower cost sputtering method.
Transparent metal oxide films can be used in many different applications, for example as dielectric films in optical coating systems or as conductive films in surface contact of thin film solar cells. For example, an aluminum-doped zinc oxide (ZnO:Al) film is used as a front contact point for a CIGS solar cell. The optical and electrical properties of the transparent metal oxide film are primarily determined by the sputtering method, depending on the application.
In many cases, it is very important to have both small electrical resistance and high transparency, especially as a front point for solar cells. Due to the energy balance of the coating process or the sensitivity of the single layer in the layer stack, the source of optimization of the substrate temperature which proves to be very advantageous for optical and electrical film properties is significantly limited. Other process parameters such as pressure, power and magnetic field strength for the optimum potential of the film properties during the ceramic process have proven to be detrimental to the improvement in the resistance-transparency combination. However, it is a known fact that better film properties can be achieved with a larger target-substrate-pitch. The use of unbalanced pole pieces also does not achieve the desired results.
In addition, reactive sputtering of transparent metal oxides does not achieve optimum transparency and electrical resistance at the same time throughout the film thickness. On the other hand, the particles forming the film in the plasma cannot achieve sufficient stoichiometric uniformity, which is manifested by the non-uniformity of the parameters of the surface resistance and the unevenness of the transparency of the resulting film. In this regard, reactive sputtering (eg, ZnO:Al) is less advantageous than non-reactive or partially reactive sputtering of ceramic tubular magnetrons.
本發明的目的是提出透明金屬氧化物膜之反應性磁控濺鍍的方法及裝置，這種方法及裝置在反應性濺鍍中要能夠進一步改善光學及電學薄膜特性。
採用申請專利範圍第1項的方法及申請專利範圍第7項的裝置即可達到上述目的。附屬於這兩個主申請專利項目的附屬專利項目的內容均為本發明的有利的實施方式。
本發明的方法及所使用的裝置可以降低鍍膜過程中磁控管的能量輸入。磁控管的能量輸入以溫度路由器的形式決定鍍膜過程中能夠達到的最高溫度。使用單一管狀磁控管，其中這個管狀磁控管的外極靴的張開角(中央極靴及外極靴之間的角度)通常小於30度及/或小於60度(兩個外極靴之間的角度)，同時具有很窄的跑道且輸入基板的能量很高，由於本發明將張開角放大且基板-標靶間距大於通常的距離(例如80mm)，使得作為光學及電學特性的最佳化源的基板溫度的可調整性明顯變大。經過改良的參數一方面會改變粒子發射特性，另一方面會使跑道變寬。
至於應調整磁系統的兩個外極靴之間的那一個角度則是由可能進入薄膜的能量輸入決定，其中由於均勻的較大的張開角的能量輸入較低，因此較為有利，同時基板-標靶間距的界限是由待沉積的鍍膜的形態學特性及附著特性決定。張開角可以是90度，或甚至大到180度都可以。例如，120度的張開角可以達到非常好的薄膜特性。
基板-標靶間距的上限是由待沉積之薄膜的特性(例如形態學特性及附著特性)決定，同時沉積速率是由電漿分佈決定。其中沉積速率對工業上使用的連續鍍膜製程是一個很重要的最佳化值。
根據一種實施方式，本發明的方法及所使用的裝置特別適於金屬標靶的沉積，因其可充分發揮反應性鍍膜方法及標靶製造的優點。
根據另一種實施方式，所使用的標靶是一種含有摻雜鋅的管狀標靶，且這個管狀標靶還有摻雜鋁及鎵中的至少一種元素。ZnO:Al膜的應用範圍很廣，因此其光學及電學特性的最佳化可視許多不同的要求而定，同時擴大其可使用的參數範圍是有利的。
根據本發明之方法的一種實施方式及所使用的裝置，在沉積出金屬氧化物膜之前，先以適當的加熱裝置至少將基板的部分段落加熱到一個基板溫度，以便在沉積過程中達到一個事先定義的最高溫度，或至少是至達一個不會被超越的溫度，至少可以將基板的部分段落均勻加熱，並使其溫度盡可能接近最大基板溫度。因為以這種方式不僅可以在通過管狀磁控管時直接調整容許的最高溫度，而且也可以在管狀磁控管間距較大的情況下調整容許的最高溫度，因此能夠確保最佳的薄膜生長。此外，將基板加熱的另一個好處是，在較大的磁控管間距下，由散逸蒸汽沉積出的薄膜部分也可以在最佳溫度或至少是接近最佳溫度的情況下生長。
可以由包含金屬氧化物膜的薄膜系統及其應用的不同的已知或可確定的參數，以及鍍膜方法的參數，決定最高溫度。其中鍍膜方法的參數可以在產生金屬氧化物的鍍膜方法中被考慮進去，或是在整個薄膜系統的鍍膜之前及/或之後的其他製程之間的相互影響中被考慮進去。例如，在將金屬氧化物膜應用於CIGS太陽能電池時， TCO沉積過程中，基板溫度在被限制在最高約200℃，否則吸收器會退化。但如果基板在之前的製程中已經被明顯加熱，則在保持最高溫度時要將這個因素考慮進去。其他的鍍膜、鍍膜系統及鍍膜方法可能會有其他的最高溫度，而這些最高溫度都可以透過試驗及模擬來決定。
例如，在製造建築玻璃鍍膜的金屬氧化物膜時，透明性是一個非常重要且有待優化的特性，或是在製造太陽能電池的前接點時，透明性及導電性是非常重要且有待優化的特性，在製程中透過加熱基板，以便對基板溫度進行特定的調整，可以將上述任何一個特性的值單獨最大化，也可以將複數個特性的值同時最大化。此外，在製造過程中，外極靴之張開角的參數及基板-標靶間距的參數是保持不變的。
對基板平面可以是由下往上濺鍍(sputter-up)或是由上往下濺鍍(sputter-down)，在鍍膜室內基板被支承在鍍膜面上，或是被一個鍍膜設置運送。前面關於本發明之方法及所使用之裝置的說明不受這兩個濺鍍方向的限制。本發明的方法及裝置亦可應用於垂直基板配置。以下描述的一個由上往下濺鍍的實施例僅供說明之用，並不會對本發明的方法及裝置造成任何限制。
SUMMARY OF THE INVENTION The object of the present invention is to provide a method and apparatus for reactive magnetron sputtering of transparent metal oxide films which are capable of further improving optical and electrical film properties in reactive sputtering.
The above object can be achieved by adopting the method of claim 1 and the device of claim 7 of the patent application. The contents of the affiliated patent items attached to the two main patent applications are all advantageous embodiments of the present invention.
The method of the invention and the apparatus used can reduce the energy input to the magnetron during the coating process. The energy input of the magnetron determines the maximum temperature that can be achieved during the coating process in the form of a temperature router. A single tubular magnetron is used, wherein the opening angle of the outer pole piece of the tubular magnetron (the angle between the central pole piece and the outer pole piece) is typically less than 30 degrees and/or less than 60 degrees (between the two outer pole pieces) The angle) has a very narrow runway and the input substrate has high energy. Since the present invention amplifies the opening angle and the substrate-target spacing is larger than the usual distance (for example, 80 mm), the optical and electrical characteristics are optimized. The adjustability of the substrate temperature is significantly increased. The improved parameters on the one hand change the particle emission characteristics and on the other hand widen the runway.
The angle between the two outer pole pieces that should be adjusted for the magnetic system is determined by the energy input that may enter the film, wherein the energy input due to the uniform larger opening angle is lower, which is advantageous, and the substrate-standard The limit of the target pitch is determined by the morphological characteristics and adhesion characteristics of the coating to be deposited. The opening angle can be 90 degrees, or even as large as 180 degrees. For example, an opening angle of 120 degrees can achieve very good film properties.
The upper limit of the substrate-to-target spacing is determined by the characteristics of the film to be deposited (e.g., morphological properties and adhesion characteristics), while the deposition rate is determined by the plasma distribution. The deposition rate is an important optimization value for the continuous coating process used in the industry.
According to one embodiment, the method of the invention and the apparatus used are particularly suitable for the deposition of metal targets, since they take full advantage of the reactive coating method and target manufacturing.
According to another embodiment, the target used is a tubular target containing zinc doped, and this tubular target is also doped with at least one of aluminum and gallium. ZnO:Al films have a wide range of applications, so the optimization of their optical and electrical properties can be determined by many different requirements, while it is advantageous to expand the range of parameters that can be used.
According to an embodiment of the method of the present invention and the apparatus used, at least a portion of the substrate is heated to a substrate temperature by a suitable heating device before depositing the metal oxide film, so as to achieve a prior The defined maximum temperature, or at least up to a temperature that will not be exceeded, can at least uniformly heat a portion of the substrate and bring the temperature as close as possible to the maximum substrate temperature. In this way, not only the maximum allowable temperature can be directly adjusted when passing through the tubular magnetron, but also the maximum allowable temperature can be adjusted with a large pitch of the tubular magnetron, so that optimum film growth can be ensured. In addition, another benefit of heating the substrate is that at a larger magnetron spacing, the portion of the film deposited by the fugitive vapor can also grow at an optimum temperature or at least near optimal temperature.
The maximum temperature can be determined by different known or determinable parameters of the thin film system comprising the metal oxide film and its application, as well as the parameters of the coating method. The parameters of the coating method can be taken into account in the coating method for producing metal oxides or in the interaction between other processes before and/or after coating of the entire film system. For example, when a metal oxide film is applied to a CIGS solar cell, the substrate temperature is limited to a maximum of about 200 ° C during TCO deposition, otherwise the absorber may degrade. However, if the substrate has been significantly heated in the previous process, this factor is taken into account when maintaining the maximum temperature. Other coatings, coating systems, and coating methods may have other maximum temperatures that can be determined by testing and simulation.
For example, transparency is a very important and to be optimized feature in the manufacture of glass-coated metal oxide films, or transparency and conductivity are important and desirable for the fabrication of solar cell front contacts. The characteristic is that by heating the substrate in the process to make a specific adjustment of the substrate temperature, the value of any of the above characteristics can be maximized individually, and the values of the plurality of characteristics can be simultaneously maximized. In addition, during the manufacturing process, the parameters of the opening angle of the outer pole piece and the parameters of the substrate-to-target spacing remain unchanged.
The substrate plane may be sputter-up or sputter-down, and the substrate in the coating chamber is supported on the coating surface or transported by a coating. The foregoing description of the method of the invention and the apparatus used is not limited by the two sputtering directions. The method and apparatus of the present invention can also be applied to vertical substrate configurations. The embodiment of the above-described sputtering from top to bottom is for illustrative purposes only and does not impose any limitation on the method and apparatus of the present invention.
1：管狀磁控管
2：標靶材料
3：托架管
4：縱軸
5：磁系統
7：中央極靴
9；外極靴
11：跑道
20：真空室
21：基板
22：基板平面
23：電極
25：基板運送方向
27：運送裝置
29：氣體輸送裝置
31：通道
α：外極靴之間的張開角
H：基板-標靶間距
Tmax：最大透明度
1: tubular magnetron
2: Target material
3: bracket tube
4: vertical axis
5: Magnetic system
7: Central pole boots
9; outer pole boots
11: Runway
20: vacuum chamber
21: substrate
22: substrate plane
23: Electrode
25: substrate transport direction
27: transport device
29: Gas delivery device
31: channel α: opening angle between outer pole pieces
H: substrate-target spacing
Tmax: maximum transparency
以下配合一個實施例對本發明的內容做進一步的說明。其中：
第1圖：根據本發明之管狀磁控管的一個斷面圖。
第2圖：一個用於執行本發明之方法的真空室。
第3圖：以本發明之方法及先前技術產生之透明金屬氧化物膜的光電薄膜特性在反應性製程中的不同工作點的比較曲線圖。
The content of the present invention will be further described below in conjunction with an embodiment. among them:
Figure 1 is a cross-sectional view of a tubular magnetron in accordance with the present invention.
Figure 2: A vacuum chamber for carrying out the method of the invention.
Figure 3: Comparative graph of the different operating points of the photovoltaic film properties of the transparent metal oxide film produced by the method of the present invention and prior art in a reactive process.
如第1圖的管狀磁控管包括一個托架管3，其外殼面被待濺鍍的標靶材料2(在本實施例中是摻雜鋁的鋅)覆蓋住。托架管3的內部設有一個磁系統5，其中磁系統5平行於托架管3(垂直於圖面)的縱軸4延伸到托架管3的整個長度。托架管3以可以轉動的方式被支撐住，也就是如式中的箭頭所示，可以繞托架管3的縱軸4轉動。磁系統5的安裝方式使其可以相對於托架管3移動，因此當托架管3 轉動時，磁系統5可以保持其相對於托架管3的位置。
磁系統5是由一個中央想靴7及一個外極靴9構成，在本實施例中，中央極靴7是構成北極，同時外極靴9是磁系統5 的南極。極性也可以是反過來的，也就是說N-S-N。磁系統5的定向是以中央極靴7在垂直於在鍍膜期間位於管狀磁控管1下方的基板(未在第1圖中繪出)的方向上進行。外極靴9先是平行於中央極靴7延伸，繞過中央極靴7的第一個終端(未在第1圖中繪出)，然後沿著反方向再度平行於中央極靴7延伸，最後閉合成一個環，其中外極靴9也會繞過中央極靴的另一個終端。在第1圖顯示的斷面圖中，磁系統5具有一個形狀類似W的斷面。
在斷面上位於中央極靴7的兩邊的外極靴9的邊以托架管3的縱軸4為準夾一個張開角α=120度。張開角也可以大到180度。
如第1圖中的虛線所示，跑道11的兩個在標靶材料2的表面上並與其平行的段落在極靴7，9之間伸展。由於張開角α相當大，使跑道11在托架管3的圓周的一個很大段落上延伸。
第3圖是以示意方式顯示一個具有如第1圖之管狀磁控管1的濺鍍設備的一個真空室20的所有元件。
在真空室20內有一個單一的管狀磁控管1，其作用是作為產生電漿之電極配置的陰極，其中電極配置還需要另一個電極23。第2圖僅是以示意方式繪出電極23，因此並未繪出與電極23連接的接線，例如電接線或冷卻劑接線，而且和真空室壁一樣可以靠在外殼上。
管狀磁控管1的延伸方向垂直於基板運送方向25，基板21被一個適當的運送置27沿著基板運送方向25運送，通過真空室，並繼續向前通過整個鍍膜設備。管狀磁控管1的縱向邊垂直於圖面，管狀磁控管1的範圍大致相當於基板寬度或是超出基板寬度。將基板21及管狀磁控管1之間的基板-標靶間距H調整為120mm。這個間距是指基板21被運送通過真空室20的基板平面22及管狀磁控管1的下緣之間的距離。
分離的氣體輸送裝置29將憜性工作氣體(氬)及反應性氣體(氧)輸送到真空室20內，使其分佈在管狀磁控管1的整個長度上。例如可以從管狀磁控管1的側面輸入工作氣體，以及從管狀磁控管1的上方輸入反應性氣體，或是反過來從管狀磁控管1的側面輸入反應性氣體，以及從管狀磁控管1的上方輸入工作氣體。如果是使用其他的鍍膜材料，則改變至少一種氣體的輸送位置也可以能是有利的。
位於基板平面22上的基板21被運送通過真空室20，在此過程中會經過管狀磁控管1，以進行反應性鍍膜。
真空室20的入口端及出口端各具有一個供基板21進出用的通道31。
可以利用一個設置在真空室20或鍍膜設備在真空室20之前的其他處理室中的加熱裝置(未在圖式中繪出)將基板21加熱，或是在之前的處理過程或鍍膜過程中將基板21加熱到所希望的溫度，如前面所述，這個溫度應使基板21的溫度在鍍膜過程中不會超過所希望的最高溫度。
在鍍膜過程中，磁力線以平行於標靶表面的方式通過的地方會點燃電漿，也就是在磁系統5的兩個極靴7，9之間的中間區域會點燃電漿。跑首道11形成於這個區域，在跑道11上，標靶材料1會從轉動中的管狀磁控管1的外表面濺射出來。由於轉動的關係，管狀磁控管1的整個表面的標靶材料會均勻的被損耗掉。濺射的標靶材料朝被加熱的基板21的方向傳播，並與被輸入真空室20的反應性氣體產生反應，成為沉積在基板21上的透明金屬氧化物。
第3圖顯示在可視範圍內，摻雜鋁的氧化鋅膜(ZnO:Al)在玻璃基板上能夠達到的最大透明度Tmax與出現在反應過程中的不同的工作點的表面電阻Rs的關係。第3圖中，曲線40顯示採用先前技術之外極靴之間的張開角α沉積出的ZnO:Al膜的最大透明度。在本例中α=50度。曲線42顯示顯示採用本發明建議之α=120度及基板-標靶間距H=150mm沉積出的ZnO:Al膜的最大透明度。在本實施例中，基板-標靶間距H被到真空室20的幾何形狀的限制，因此在不同的幾何形狀條件下，可以如前面所述採用不同的基板-標靶間距H，以達到最佳的薄膜特性。
The tubular magnetron as in Fig. 1 comprises a carrier tube 3 whose outer surface is covered by a target material 2 to be sputtered (in this embodiment, aluminum-doped zinc). The interior of the carrier tube 3 is provided with a magnetic system 5 in which the magnetic system 5 extends parallel to the longitudinal axis 4 of the carrier tube 3 (perpendicular to the drawing) to the entire length of the carrier tube 3. The carrier tube 3 is rotatably supported, i.e., rotatable about the longitudinal axis 4 of the carrier tube 3 as indicated by the arrows in the formula. The magnetic system 5 is mounted in such a way as to be movable relative to the carrier tube 3 so that the magnetic system 5 can maintain its position relative to the carrier tube 3 as the carrier tube 3 rotates.
The magnetic system 5 is composed of a central shoe 7 and an outer pole shoe 9. In the present embodiment, the center pole piece 7 constitutes the north pole and the outer pole piece 9 is the south pole of the magnetic system 5. The polarity can also be reversed, that is to say NSN. The orientation of the magnetic system 5 is carried out in the direction of the central pole piece 7 perpendicular to the substrate (not depicted in Figure 1) below the tubular magnetron 1 during the coating process. The outer pole piece 9 first extends parallel to the central pole piece 7, bypasses the first end of the central pole piece 7 (not depicted in Figure 1), and then extends parallel to the central pole piece 7 in the opposite direction, and finally Closed into a loop in which the outer pole piece 9 also bypasses the other end of the central pole piece. In the cross-sectional view shown in Fig. 1, the magnetic system 5 has a section shaped like W.
The sides of the outer pole piece 9 on both sides of the central pole piece 7 in cross section are sandwiched by the longitudinal axis 4 of the carrier tube 3 by an opening angle α = 120 degrees. The opening angle can also be as large as 180 degrees.
As indicated by the dashed lines in Fig. 1, two sections of the runway 11 on the surface of the target material 2 and parallel thereto extend between the pole pieces 7, 9. Since the opening angle α is relatively large, the runway 11 is extended over a large section of the circumference of the bracket tube 3.
Figure 3 is a schematic representation of all of the elements of a vacuum chamber 20 having a sputtering apparatus such as the tubular magnetron 1 of Figure 1.
Within the vacuum chamber 20 is a single tubular magnetron 1 which acts as a cathode for the electrode configuration of the plasma, wherein the electrode configuration also requires another electrode 23. Fig. 2 only depicts the electrode 23 in a schematic manner, so that the wiring connected to the electrode 23, such as an electrical wiring or a coolant wiring, is not depicted, and can be placed against the outer casing like the vacuum chamber wall.
The tubular magnetron 1 extends in a direction perpendicular to the substrate transport direction 25, and the substrate 21 is transported in a substrate transport direction 25 by a suitable transport 27, through the vacuum chamber, and continues through the entire coating apparatus. The longitudinal side of the tubular magnetron 1 is perpendicular to the plane of the drawing, and the extent of the tubular magnetron 1 is substantially equivalent to the width of the substrate or beyond the width of the substrate. The substrate-target pitch H between the substrate 21 and the tubular magnetron 1 was adjusted to 120 mm. This pitch refers to the distance between the substrate plane 22 through which the substrate 21 is carried through the vacuum chamber 20 and the lower edge of the tubular magnetron 1.
The separated gas delivery device 29 delivers the inert working gas (argon) and the reactive gas (oxygen) into the vacuum chamber 20 to be distributed over the entire length of the tubular magnetron 1. For example, a working gas can be input from the side of the tubular magnetron 1, and a reactive gas can be input from above the tubular magnetron 1, or vice versa, and a reactive gas can be input from the side of the tubular magnetron 1, and from the tubular magnetron A working gas is input above the tube 1. If other coating materials are used, it may also be advantageous to change the delivery position of the at least one gas.
The substrate 21 on the substrate plane 22 is carried through the vacuum chamber 20, during which it passes through the tubular magnetron 1 for reactive coating.
The inlet end and the outlet end of the vacuum chamber 20 each have a passage 31 for the substrate 21 to enter and exit.
The substrate 21 may be heated by a heating device (not shown in the drawings) disposed in the vacuum chamber 20 or other processing chambers before the vacuum chamber 20, or during the previous process or coating process. The substrate 21 is heated to a desired temperature which, as previously described, is such that the temperature of the substrate 21 does not exceed the desired maximum temperature during the coating process.
During the coating process, the magnetic field lines ignite the plasma in a manner parallel to the surface of the target, that is, the plasma is ignited in the middle between the two pole pieces 7, 9 of the magnetic system 5. The running track 11 is formed in this area, and on the runway 11, the target material 1 is sputtered from the outer surface of the rotating tubular magnetron 1. Due to the rotational relationship, the target material of the entire surface of the tubular magnetron 1 is uniformly lost. The sputtered target material propagates in the direction of the heated substrate 21 and reacts with the reactive gas introduced into the vacuum chamber 20 to become a transparent metal oxide deposited on the substrate 21.
Figure 3 shows the relationship between the maximum transparency Tmax that the aluminum-doped zinc oxide film (ZnO:Al) can achieve on a glass substrate and the surface resistance Rs at different operating points during the reaction in the visible range. In Fig. 3, curve 40 shows the maximum transparency of the ZnO:Al film deposited using the opening angle α between the pole pieces outside the prior art. In this example α = 50 degrees. Curve 42 shows the maximum transparency of the ZnO:Al film deposited using the proposed alpha = 120 degrees and substrate-to-target spacing H = 150 mm. In the present embodiment, the substrate-to-target pitch H is limited to the geometry of the vacuum chamber 20, so that under different geometric conditions, different substrate-target pitches H can be used as described above to achieve the most Good film properties.
1：管狀磁控管
2：標靶材料
3：托架管
4：縱軸
5：磁系統
20：真空室
21：基板
22：基板平面
23：電極
25：基板運送方向
27：運送裝置
29：氣體輸送裝置
31：通道
α：外極靴之間的張開角
H：基板-標靶間距
1: tubular magnetron
2: Target material
3: bracket tube
4: vertical axis
5: Magnetic system
20: vacuum chamber
21: substrate
22: substrate plane
23: Electrode
25: substrate transport direction
27: transport device
29: Gas delivery device
31: channel α: opening angle between outer pole pieces
H: substrate-target spacing