1243237 九、發明說明： 【發明所屬之技術領域】 本專利申請案係基於2002年6月28曰申請之臨時專利申 請案第60/392,380號。 s本發明係關於質流計，而更特定言之，係關於質流計之 晶片類型的溫度感應器，以及四個感應器的橋接電路。 【先前技術】 有許多不同的方法被用來測量氣體與流體的流速。這些 方法通常被分成兩類··測量體積流的，以及測量測量質量 流的。 體積流量計的實例是一種錐形管’氣體或液體流經該 管，會移動管中的浮標。當沒有流量時，浮標靜止於管子 底部，封住其較窄的一端。當液體流經管子時，浮標會升 起’而升起的高度正比於液體體積流量。 體積流量計的主要問題與氣體流速的測量有關。改變氣 體的壓力或溫度，會造成流量測量不準確。 傳統上使用質流計（MFMs)來操作控制液體流經導管流 速的閥；MFM與閥的組合稱為質流控制器（MFC)。這些裝 置用於很多需要精準的氣體或液體流速控制系統中，如在 半導體製程工業中，可以用來傳遞生長或摻雜於半導體材 料中的氣體原子，其中氣體流速是重要的良率參數。2〇〇〇 年5月15-16日，於國立標準與技術研究院（NIST)舉辦之「半 導體工業之質流測量與控制研討會」，其結果發表於2〇〇〇 年7月20曰，其中有討論半導體工業之MFCs。MFCs超越體 93276.doc 1243237 積流量測量的優點，是由於線壓力與溫度的變化的緣故， 質量流會比較容易受精確度誤差的影響。已知的MFCs包含 可浸沒式（immersible)熱MFCs，熱MFCs，與差動壓力MFCs。 熱MFCs是半導體製程工業中，最常使用的MFC類型。他 們是比較便宜的組件，並且在價格與性能之間，提供良好 的妥協。在可浸沒式MFCs中，一或更多感應器就位於流動 的流體中，其同時具有毛細管MFCs，其中毛細管平行主要 的流體導管，而管子外面則有一或更多感應器。 在可浸沒式熱MFCs中，浸沒的溫度感應器也當作加熱-器，當電流經過時，便會加熱。當流體沒有流動時，溫度 感應器保持某些已知的常數溫度。由於流體將熱帶走，流 動的流體會降低感應的溫度。感應溫度下降的幅度正比於 流體的質流速度。在感應器材料會污染流動的流體，或其 本身會被流體污染的應用中，可以將感應器封裝起來。 在另一種近可浸沒式的熱MFCs中，加熱器浸沒於上游， 而溫度感應器則浸沒於下游。上游加熱器之操作所造成之 感應器位置的流體溫度上升量，與流體的質流速率有關聯。 在毛細管熱MFCs中，已知部分流體係經由加熱的毛細管 導引，而剩下的流體則繞過毛細管。該管係由環繞上游外 表面之金屬電線所加熱，其下游並有溫度感應線圈。通常 是使用白金線，因為其電阻隨溫度改變的函數是已知的5 這允許其當作加熱器或溫度感應器。某些MFC製造商使用 薄膜白金電阻溫度裝置，其在薄膜絕緣體（通常是鋁）上，包 含白金薄層，其中該薄膜絕緣體係沈積於毛細管的外表 93276.doc 1243237 面。白金薄膜層的電阻改變是溫度的函數。 經由毛細管轉移的氣體吸收一些來自上游線圈的熱。如 果沒有氣體流動，管子將被均勻地加熱，而上游與下游感 應器將會感應相等的溫度。一旦氣體開始流過管子，其熱 吸收容量會使管子的上游部分降溫，同時加熱下游的部 分；溫差隨氣流增加而增加。板上或遠端的電子零件提供 感應器之激發電壓或電流，同時也監視感應的反應。舉例 來說，如果施加電流，則監視跨過線圈的電壓，使線圈的 電阻是已知的。既然感應器之電阻隨已知溫度函數而變-化，可以由其電流與電壓來決定感應器上的溫度。 熱M F C s可以是固定電流或固定溫度的裝置。在固定電流 的裝置中，溫度感應器以橋狀電路，電子地連接兩個電阻 元件；其他元件則是被動式電阻器。感應器電阻將固定的 激發電流轉換成熱，而沿著毛細管提供均勻的溫度梯度。 在固定溫度的裝置中，感應器也連接成雙感應器橋接電 路，但是MFC電子元件對橋接電路提供固定電壓，而不是 固定電流。流經管子的流體會降低上游感應器的溫度，而 這會降低其電阻（對正的溫度係數感應器而言），使更多電流 流過。激發電流的增加造成感應器散發更多熱，而這補償 流體散失的熱。該額外的電流正比於流體的質流速率。通 常使用白金當作感應元件。 雖然這些已經被廣泛地運用，目前市售的MFCs有下列之 一或更多特徵：相當高的溫度感應偏移，低敏感度，長反 應時間，與製造期間，處理超細白金線之困難度有關的耗 93276.doc 1243237 、 為里化低敏感溫度感應裔之電子反應的額外電子元 件，以及與高敏感度感應器一起使用時，低敏感度溫度感 應益之電路所引起的錯誤。 【發明内容】 在本發明之一態樣中，至少放置四個互相分隔的溫度感 應时以感應流經導管的流體溫度，並且連接成四個感應 裔的橋接電路，以提供流體質流速率的指示。感應器是不 連接的，而且相對於導管對稱地分佈，其中最好是沿著流 動的路徑，在導管的兩個位置上，於每一相對的側面放置-一對感應器。 在本^明之另一恶樣中，溫度感應器是分離晶片類型的 元件感應裔的選擇包含半導體材料，如碳化石夕（Sic)或石夕， 其中在晶片與導電的導管，以及氮化鋁（A1N)基板上的薄膜 鎢層之間，具有氧化物接合面。感應器可以用電子絕緣的 薄膜來包覆，而在薄膜的其他側面上有一電路，該電路延 伸經過薄膜，以接觸感應器。該感應器可以經由感應器與 導官上都有的鈦鎢（TiW)合金或鎳（Ni)層，安裝於導管上， 每個支持一層金（Au)。可以使用各種不同的感應器位 置，包含導管外表面，導管内表面，導管壁的開口，或投 射到導管内部。 曰曰片頒型的感應器使多重感應器可以對稱地放在導管周 圍而且可以是沿著流體流動的路徑放在單一位置或多個 位置上。對稱放置得以獲得更精確的溫度感應，而這對於 四個感應器的橋接電路，或利用一或更多感應器對的其他 93276.doc 1243237 MFM配置，都是有用的。 經由對導管之控制閥施加上述mfm之輸出，則可以使用 MFM來操控流經導管的流體。 對於熟諳此蟄之士而言，從以下詳細敘述與附圖，本發 明之這些與其他特徵與優點，將是顯而易見的。 【實施方式】 圖1說明根據本發明之一具體實施例的毛細管MFM。經由 主導管2流動的一小部分流體，無論是氣體或液體，被轉移 到毛細管4 ;主導管與毛細管結構可以是傳統的型式。主導 官與毛細官的剖面以傳統的方式精確地製作，以確保其流 體流動是相同的。可是，不是之前提供於毛細管周圍的白 金線圈，而是沿著管子，位於上游位置的—對晶片類型的 溫度感應器U1與U2，以及沿著管子，位於下游位置的一對 晶片類型的溫度感應器01與!)2。每一對感應器最好以18〇 度的間隔對稱地放置於管子的對面。在流體溫度從管子一 端到另一端些微變化的情況中，這允許其對管子内之流體 溫度做更精確的感應。舉例來說，如果感應器位於沿著毛 細官水平的部分’而不是所示之垂直的部分，則升高的執 會錄高的感應II制_微高—些的溫度，而較低的感 應器則會摘測到稍微低-些的溫度。對 教消除這些差異，同時更以地將熱引進㈣中。= 管壁具有高的熱傳導率，使管内的流體溫度準確地傳送到 感應器；為此，通常使用不銹鋼。 圖2說明四感應器之橋接電路，其係用來感應經過^之 93276.doc -10- 1243237 :細：之流體的質流速率。該橋接電路被分成左與右分 下二分支具有上與下的部分。左分支包含-對上游與 J感應器，其中上游感應器U2位於其較上的部分，而下 游感應器D2則位於較低的位置。右分支也包含—對上游與 下游感應，但是其在分支中的相對位置是保留的；下游 感應器Di位於較上的部分，而上游感應器川則位於 部分。 一 來自電流源II的啟動電流回饋至橋接電路的上面，而電 流則從橋接電路流出，經由電阻器R，流到接地之參考電 位。橋接電路的輸出分別是在右分支之01與口1之間，以及 在左分支之U2與D2之間的連線上的電壓¥〇1與％2。 每一感應|§具有相同的結構，因此具有相同電阻溫度係 數。流經毛細管的流體會將熱從上游感應器111與1；2，傳送 到下游感應器D1與D2。因此，對於具有正的電阻溫度係數 的感應器，這對D1/D2造成比對U1/U2高的電阻。橋接電路 左为支的總電阻會保持與其右分支相同的總電阻，因此相 同的電流會流經每一分支。可是，因為每一電阻等級的差 異，右分支之較上面的部分，跨越D1的電壓降會是比跨越 較低部分U1之電壓降大的電壓降，而相反地，左分支之較 上面的部分’跨越U2的電壓降會是比其跨越較低部分D2之 電壓降小的電壓降。因此，Vo 1會是比Vo2高的電壓等級， 其中電壓差表示質流速率。 由於除了 Vo 1反應流體流動而上升以外，v〇2還下降，因 而產生複合的效果，所以圖2之電路獲得比先前雙感應器橋 93276.doc -11 - 1243237 接電路更高程度的敏感度。也已經發現可以用此一電路而 播需放大感應器輸出，來達成有用的質流速率監視。 s圖3說明對於四感應器橋接電路而言，模擬的電壓差輸出 是上游與下游感應器之間溫度差的函數。該曲線是實質上 線性的，因此在整個完全線性的範圍上，只需要決定沿著 曲線上的兩個點，即可獲知流速，避免更複雜之方程式的 需求，其中該等方程式可能需要被嵌入微處理器之微晶片 中。 圖4說明在流體導管4上，晶片類^之溫度感應器的配 置，其係根據本發明。碳化邦⑹與石夕晶片是較佳的；其 在電阻溫度係數是正的區域中，具有相似的敏感度。碳化 矽(SiC)具有比矽高的操作溫度，而且沒有擴散。也可以利 用其他半導體材料，但是其他半導體材料通常比較不容易 使用，無法形成天然氧化物，因此不會比碳化矽或矽更敏 感。電子接觸襯墊6係用來當作每一晶片之相對端的金屬化 層並使电子引線至晶片能夠連線，而能夠施加激發電壓 或電流，以及監視晶片的反應。 圖4所示之引線配置對應於圖2之四元件橋接電路，其中 上游晶片υι之一端經由引線8，連接至晶片D2的下游端， 其他上游晶片U2之上游端經由引線1〇，連接至其他下游晶 片D1的下游端，ui與D1的正面，經由引線12連接在一起， U2與D2的正面，經由引線14連接在一起，n施加於引線1〇， 電阻益尺連接引線8，Vol取自引線12，而v〇2則取自引線 14。雖然將引線12與14說明成是簡短的，但是他們的實際 93276.doc -12- 1243237 長度可以有相當的延伸，例如將其連接至引線輸出電子。 為了質流速率監視的㈣’這可以將連接晶片之間的熱路 位長度杧加至引線貫負上不是熱傳導的位置，因此避免晶 片之間額外的熱路徑中這些額外的熱路徑可能會干擾 測量。其他引線將以類似的方式安排。 圖5疋個不合尺度比例的剖面圖，說明對稱配置的晶片 U1與U2可以黏合於導管4。電子絕緣，但是熱傳導的層‘工 與16-2分別形成於^與！；]的面上，以允許導電的晶片直 接觸不錄鋼導管4與黏合材料，而不需產生短小的電子電 路。電子絕緣層16-1與16·2可以整個整合在—起，沈積或黏 合於晶片部分上。使用碳切（Sic)切作為感應器，最好 藉由氧化晶片面對導管的表面來形成電子絕緣層。 熱傳導接合材料18將晶片類型的感應器黏合於導管。如 果黏合材料不直接肖晶片氧化物與導管材料接纟，則首先 將適當財間接合材料沈積料録面±，其巾黏合材料 通常是焊料。在圖5中’接合材料18是金/錫共溶合金焊料， 其將不會直接黏合於電子絕緣的氧化物層i“與Μ，或者 是不錢鋼管4上。為了產生良好的接合，鶴欽（)合全或 錄（Ni)的2(M與20_2層最好是約彻_15〇〇埃厚，其分別沈積 於晶片氧化物層⑹與心上。類似的鎢鈦(Tiw)合金或‘ ⑽層20-3沈積於管子4的外表面。金㈣層叫，瓜技 22-3最好是4__25_埃厚，其接著分別沈積於鶴欽㈣) 合金或錄（N0中間層20_丄，2〇_2與2〇_3上。接著可以施用黏 合至金㈣表面的金/錫共炼合金焊料18，以將兩晶片㈣ 93276.doc Ϊ243237 U2結合於管子的對面 有非常高的熱傳導， 的焊料。 。金是最好的接合材料，因為其具 而且不會很快氧化。有很多金接合金 為了進步4呆瘦整個配件，並對適當地方的感應器提供 額外的支持，可以將配件遮蔽於絕緣套管24中，如由e.工.1243237 IX. Description of the invention: [Technical field to which the invention belongs] This patent application is based on provisional patent application No. 60 / 392,380 filed on June 28, 2002. The present invention relates to a mass flow meter, and more specifically, to a wafer type temperature sensor of the mass flow meter, and a bridge circuit of four sensors. [Prior art] There are many different methods used to measure the velocity of gas and fluid. These methods are usually divided into two categories: • measuring volume flow and measuring mass flow. An example of a volumetric flow meter is a conical tube 'through which gas or liquid flows, which moves the buoy in the tube. When there is no flow, the buoy rests at the bottom of the tube, sealing its narrower end. When the liquid flows through the tube, the buoy will rise 'and its height is proportional to the liquid volume flow. The main problem of volume flow meters is related to the measurement of gas flow rate. Changing the pressure or temperature of the gas will cause inaccurate flow measurement. Mass flow meters (MFMs) have traditionally been used to operate valves that control the flow rate of liquid through a conduit; the combination of MFM and valve is called a mass flow controller (MFC). These devices are used in many gas or liquid flow control systems that require precision, such as in the semiconductor process industry, and can be used to transfer gas atoms that are grown or doped in semiconductor materials, where the gas flow rate is an important yield parameter. "Semiconductor Mass Flow Measurement and Control Seminar" held at the National Institute of Standards and Technology (NIST) on May 15-16, 2000. The results were published on July 20, 2000. Among them are MFCs that discuss the semiconductor industry. The advantage of MFCs transcendence body 93276.doc 1243237 is that due to changes in line pressure and temperature, mass flow is more susceptible to accuracy errors. Known MFCs include immersible thermal MFCs, thermal MFCs, and differential pressure MFCs. Thermal MFCs are the most commonly used type of MFC in the semiconductor process industry. They are relatively inexpensive components and offer a good compromise between price and performance. In submersible MFCs, one or more sensors are located in the flowing fluid, and they also have capillary MFCs, where the capillary is parallel to the main fluid conduit and the tube has one or more sensors outside. In submersible thermal MFCs, the immersed temperature sensor also acts as a heater, and when the current passes, it heats up. When the fluid is not flowing, the temperature sensor maintains some known constant temperature. As the fluid moves tropically, the flowing fluid will reduce the induced temperature. The magnitude of the induced temperature drop is proportional to the mass flow velocity of the fluid. The sensor can be packaged in applications where the sensor material can contaminate flowing fluids, or where the fluid itself can be contaminated by the fluid. In another type of near-submersible thermal MFCs, the heater is immersed upstream and the temperature sensor is immersed downstream. The increase in fluid temperature at the sensor location caused by the operation of the upstream heater is related to the mass flow rate of the fluid. In capillary thermal MFCs, it is known that a partial flow system is directed through a heated capillary tube, while the remaining fluid bypasses the capillary tube. The tube is heated by a metal wire that surrounds the upstream outer surface and has a temperature sensing coil downstream. Platinum wire is usually used because its resistance as a function of temperature is known5 This allows it to be used as a heater or temperature sensor. Some MFC manufacturers use thin-film platinum resistance temperature devices that contain a thin layer of platinum on a thin-film insulator (usually aluminum), where the thin-film insulation system is deposited on the outer surface of the capillary tube 93276.doc 1243237. The resistance change of the platinum thin film layer is a function of temperature. The gas transferred via the capillary absorbs some of the heat from the upstream coil. If no gas is flowing, the tube will be heated uniformly, and the upstream and downstream sensors will sense equal temperatures. Once the gas begins to flow through the tube, its heat absorption capacity will cool the upstream portion of the tube and heat the downstream portion at the same time; the temperature difference will increase as the airflow increases. Electronic parts on the board or at the far end provide the excitation voltage or current of the sensor and also monitor the induced response. For example, if a current is applied, the voltage across the coil is monitored so that the resistance of the coil is known. Since the resistance of an inductor changes with a known temperature function, the temperature on the inductor can be determined by its current and voltage. The thermal M F C s may be a fixed current or fixed temperature device. In a fixed current device, the temperature sensor is connected in a bridge circuit electronically to two resistive elements; the other elements are passive resistors. The inductor resistance converts a fixed excitation current into heat, while providing a uniform temperature gradient along the capillary. In fixed temperature devices, the sensors are also connected as a dual inductor bridge circuit, but the MFC electronics provide a fixed voltage instead of a fixed current to the bridge circuit. Fluid flowing through the tube reduces the temperature of the upstream sensor, which reduces its resistance (for positive temperature coefficient sensors) and allows more current to flow. An increase in the excitation current causes the sensor to emit more heat, which compensates for the heat lost by the fluid. This additional current is proportional to the mass flow rate of the fluid. Platinum is usually used as the sensing element. Although these have been widely used, currently commercially available MFCs have one or more of the following characteristics: considerable temperature-induced offset, low sensitivity, long response time, and difficulty in handling ultra-fine platinum wires during manufacturing Consumption 93276.doc 1243237, additional electronic components to reduce the electronic response of low-sensitivity temperature sensors, and errors caused by low-sensitivity temperature-sensing circuits when used with high-sensitivity sensors. [Summary of the Invention] In one aspect of the present invention, at least four mutually spaced temperature sensors are placed to sense the temperature of the fluid flowing through the conduit, and are connected into a bridge circuit of the four sensor lines to provide a fluid mass flow rate. Instructions. The sensors are not connected and are symmetrically distributed with respect to the catheter. It is best to place a pair of sensors on each of the opposite sides of the catheter at two locations along the path of the flow. In another aspect of the present invention, the temperature sensor is a component of a separate wafer type. The selection of the sensor family includes semiconductor materials, such as carbon carbide (Sic) or stone, where the wafer and conductive conduit, and aluminum nitride (A1N) The thin-film tungsten layer on the substrate has an oxide bonding surface. The inductor can be covered with an electrically insulating film, and there is a circuit on the other side of the film that extends through the film to contact the inductor. The sensor can be mounted on the catheter via a titanium tungsten (TiW) alloy or nickel (Ni) layer on both the sensor and the guide, each supporting a layer of gold (Au). A variety of different sensor positions can be used, including the outer surface of the catheter, the inner surface of the catheter, the opening in the catheter wall, or projection into the catheter. The film-type sensors allow multiple sensors to be placed symmetrically around the catheter and can be placed in a single location or multiple locations along the path of fluid flow. Symmetric placement enables more accurate temperature sensing, which is useful for bridge circuits with four sensors, or other 93276.doc 1243237 MFM configurations that use one or more sensor pairs. By applying the above mfm output to the control valve of the catheter, the MFM can be used to manipulate the fluid flowing through the catheter. To those skilled in the art, these and other features and advantages of the present invention will be apparent from the following detailed description and accompanying drawings. Embodiment FIG. 1 illustrates a capillary MFM according to a specific embodiment of the present invention. A small part of the fluid, whether gas or liquid, flowing through the main conduit 2 is transferred to the capillary 4; the main conduit and the capillary structure may be of a conventional type. The cross-sections of the chief and capillaries are accurately made in a traditional manner to ensure that their fluid flow is the same. However, instead of the platinum coil previously provided around the capillary, it is located upstream along the tube-pair of wafer-type temperature sensors U1 and U2, and a pair of wafer-type temperature sensors located downstream along the tube.器 01 与!) 2. Each pair of sensors is preferably placed symmetrically across the tube at 180 ° intervals. In the case where the temperature of the fluid changes slightly from one end of the tube to the other, this allows it to more accurately sense the temperature of the fluid in the tube. For example, if the sensor is located along the horizontal portion of the capillary ', rather than the vertical portion shown, then the elevated induction will record a high induction II system_slightly higher temperature, and a lower induction The device will pick up a slightly lower temperature. Religion eliminates these differences, and at the same time introduces heat into the country. = The high thermal conductivity of the tube wall allows the temperature of the fluid in the tube to be accurately transmitted to the sensor; for this reason, stainless steel is usually used. FIG. 2 illustrates a bridge circuit of four sensors, which is used to sense the mass flow rate of a fluid passing through the 93276.doc -10- 1243237. The bridge circuit is divided into left and right branches and the two branches have upper and lower sections. The left branch contains-pairs of upstream and J sensors, where the upstream sensor U2 is located in the upper part and the downstream sensor D2 is located in the lower position. The right branch also contains the upstream and downstream induction, but its relative position in the branch is reserved; the downstream sensor Di is located in the upper part, and the upstream sensor Chuan is located in the part. A starting current from the current source II is fed back to the bridge circuit, and the current flows from the bridge circuit and flows through the resistor R to the ground reference potential. The outputs of the bridge circuit are the voltages 〇1 and% 2 on the connection between 01 and port 1 on the right branch, and U2 and D2 on the left branch, respectively. Each induction | § has the same structure and therefore has the same resistance temperature coefficient. The fluid flowing through the capillary will transfer heat from the upstream sensors 111 and 1; 2 to the downstream sensors D1 and D2. Therefore, for an inductor with a positive temperature coefficient of resistance, this results in a higher resistance for D1 / D2 than for U1 / U2. Bridge Circuit The total resistance of the left branch will maintain the same total resistance as its right branch, so the same current will flow through each branch. However, because of the difference in each resistance level, the voltage drop across D1 on the right branch will be greater than the voltage drop across U1 on the lower branch, and conversely, the left branch will be on the upper section. 'The voltage drop across U2 will be a smaller voltage drop than the voltage drop across its lower portion D2. Therefore, Vo 1 will be a higher voltage level than Vo2, where the voltage difference represents the mass flow rate. Because in addition to the flow of Vo 1 reaction fluid rises, v〇2 also drops, resulting in a composite effect, the circuit of Figure 2 obtains a higher degree of sensitivity than the previous dual sensor bridge 93276.doc -11-1243237 . It has also been found that this circuit can be used to broadcast the sensor output to achieve useful mass flow rate monitoring. Figure 3 illustrates that for a four-inductor bridge circuit, the simulated voltage difference output is a function of the temperature difference between the upstream and downstream inductors. The curve is substantially linear, so over the entire linear range, you only need to decide two points along the curve to get the flow rate, avoiding the need for more complex equations, which may need to be embedded Microprocessor chip. Fig. 4 illustrates the configuration of a wafer-like temperature sensor on the fluid conduit 4 according to the present invention. Carbonized wafers and Shixi wafers are preferred; they have similar sensitivities in areas where the temperature coefficient of resistance is positive. Silicon carbide (SiC) has a higher operating temperature than silicon and does not diffuse. Other semiconductor materials can also be used, but other semiconductor materials are usually less easy to use and cannot form natural oxides, so they are not more sensitive than silicon carbide or silicon. The electronic contact pad 6 serves as a metallization layer on the opposite end of each wafer and enables electronic leads to be connected to the wafer, to apply an excitation voltage or current, and to monitor the reaction of the wafer. The lead arrangement shown in FIG. 4 corresponds to the four-element bridge circuit of FIG. 2, in which one end of the upstream chip υι is connected to the downstream end of the chip D2 via the lead 8, and the upstream ends of the other upstream chips U2 are connected to the other via the lead 10. The downstream end of the downstream chip D1, the front sides of ui and D1, are connected together through the lead 12, the front sides of U2 and D2 are connected together through the lead 14, n is applied to the lead 10, and the resistance scale is connected to the lead 8. Vol is taken from Lead 12 is taken from v02. Although the leads 12 and 14 are described briefly, their actual 93276.doc -12- 1243237 can be extended considerably, such as connecting them to the leads to output electrons. For mass flow rate monitoring, this can increase the length of the thermal path between the connected wafers to positions that are not thermally conductive on the lead wires, so avoiding these additional thermal paths in the additional thermal paths between the chips may interfere measuring. The other leads will be arranged in a similar manner. FIG. 5 is a cross-sectional view of an out-of-scale scale, illustrating that the symmetrically arranged wafers U1 and U2 can be adhered to the catheter 4. Electronically insulated, but the thermally conductive layers ‘工 和 16-2 are formed at ^ and! ;] To allow the conductive wafer to directly contact the non-recording steel conduit 4 and the bonding material without generating a short electronic circuit. The electronic insulating layers 16-1 and 16 · 2 can be integrated together, deposited or adhered to the wafer portion. Using a carbon cut (Sic) cut as the sensor, it is best to form the electronic insulation layer by oxidizing the surface of the wafer facing the catheter. The thermally conductive bonding material 18 bonds a wafer-type sensor to the catheter. If the bonding material is not directly connected to the wafer oxide and the catheter material, first deposit the appropriate material for the bonding material ±. The towel bonding material is usually solder. In FIG. 5 'the joining material 18 is a gold / tin eutectic alloy solder, which will not directly adhere to the electronically insulated oxide layer i' and M, or the non-ferrous steel pipe 4. In order to produce a good joint, Qin () Hequan or Lu (Ni) 2 (M and 20_2 layer is preferably about _1500 Å thick, which are deposited on the wafer oxide layer ⑹ and the core respectively. Similar tungsten-titanium (Tiw) alloy Or the ⑽ layer 20-3 is deposited on the outer surface of the pipe 4. The gold ㈣ layer is called, the melon 22-3 is preferably 4__25_ Angstrom thick, which is then deposited on the He Qin㈣) alloy or recorded (N0 intermediate layer 20_丄, 2〇_2 and 2〇_3. Then, a gold / tin co-melted alloy solder 18 bonded to the surface of gold ㈣ can be applied to bond the two wafers ㈣ 93276.doc Ϊ 243237 U2 to the opposite side of the tube with a very high Thermally conductive solder. Gold is the best bonding material because it has and does not oxidize very quickly. There are many gold bonding golds to improve the quality of the whole part and provide additional support for the appropriate place of the sensor. The accessories are shielded in the insulating sleeve 24, such as by e. 工.
Dupont de Nemours 公 al ^Ιτ Μ /3£ ^ ^ α .Dupont de Nemours, al ^ Ιτ Μ / 3 £ ^ ^ α.
了均勻的熱分佈，當對鎢導體施加加熱電流時，鎢導體最 好沿著基板30上彎彎曲曲的圖案，並且終止於一對分隔之 接觸襯墊32的每一終端。鎢提供高度的熱敏感度， 和氮化鋁（Α1Ν)—起使用時，因為兩者很匹配的溫度膨脹係 數，其可以容許大的溫度範圍。薄膜鎢層通常是大約 10-1000微米厚。此一溫度感應器是由本發明之發明人其中 之一，詹姆斯帕绅（James D_ Parsons)於本申請案同一天申 請，目前為申請中之專利申請案第1〇/6〇8,737號的主題。 圖7說明根據本發明之感應器34，放在沿著導管4内壁上 的位置。該感應器以類似於外部感應器的方式，結合於壁 上，並且由感應器使用的材料，決定感應器與導管壁之間 有或沒有電子絕緣層。感應器引線36可以從導管遠端的位 置，或直接從導管壁中的絕緣套引出。如所說明之感應器 在導管内的放置，允許對流經導管之液體非常快速與準確 93276.doc -14· !243237 的追蹤’但是其要求感應|§或結合材料不能與流體起反應。 現在請參考圖8 ’其說明安裝感應器36之其他選擇，其中 感應器安裝於導管壁之開口，使流體直接加熱其面對導管 内部的表面。感應器接觸點3 8位於其外表面，並且是容易 接近的。該感應器與其安裝之導管開口，應該夠小，使感 應器不會突出到進入導管，而且沿其周圍，要能獲得良好 的接合，以將感應器固定於適當的地方，避免流體從導管 流失° 如上所述，该感應裔可以是四元件橋接的一部分，無論· 是雙感應器MFM之上游或下游元件，或是以單一感應器 MFM獨自運作的。所顯示之電流源12經由感應器引導電 流，並具有一電壓計40,該電壓計4〇監視感應器反應施加 電流的電壓。比較施加電流與所測量之電壓，得出感應器 的電阻；這可以和沒有流動時的電阻比較，或者是與上或 下游感應器的電阻比較，以決定導管内的流體質流速率。 為了避免流體與感應器或其接合材料起反應，以保護感 應器與/或避免流體污染，圖％與处所示之晶片類型的感應 f 42,可以安裝於保護罩44的裡面，其中該保護罩料在^ 巨4内形成封閉的隔間，避開流經導管的流體。對於不銹鋼 導管而言，保護罩44最好是不銹鋼。引線46可以從感應器' 經過導管壁内的外罩（未顯示），向上延伸。 圖10說明浸沒式熱MFM，纟中將_導體或熱敏電阻之晶 片頡型的感應器48，固定於導管4内流動的流體中，位於陶 尤晶片基板50的終端上。該基板承載由沈積金屬之薄層所 93276.doc -15- 1243237 形成的電子弓丨線52，其允許對感應器48施加激發電壓或電 流’也允許電路板上或遠端的MFM電子元件監視感應器的 電阻。 圖11說明利用圖1〇之浸沒式]^117]^的MFC，其亦可以使用 本發明所提議之任何其他MFM具體實施例。流動控制閥54 位於浸沒式感應器48之上游，其中電子封包56經由基板5〇 上的引線痕跡（未顯示），監視感應器的特性。MFC系統外罩 60外面上的電子接合面58，對該系統提供電子輸入與輸 出。電子元件56經由引線64,提供信號給控制閥促動器62，一 以反應偵測到的流體質流速率，控制控制閥的運作，而允 許流速維持在理想的程度，而不受上游或下游線壓力或溫 度變化的干擾。 雖然已經顯示與敘述本發明之特定具體實施例，熟諳此 藝之士將了解，可以有很多變化或其他具體實施例。因此， 不希望本發明僅限於延伸申請專利範圍所陳述的。 【圖式簡單說明】 圖1係毛細-管MFM之簡化的剖面圖，其係根據本發明； 圖2係四感應器橋接電路之概圖，其反應圖1之感應器， 提供MFM輸出； 圖3係一曲線圖，說明上游與下游感應器之間的溫度，對 橋接輸出的線性關係； 圖4係晶片類型溫度感應器之透視圖與概圖的合成簡 圖，其中根據本發明，將晶片類型之溫度感應器安排成mfm 四感應器橋接狀態； 93276.doc -16- 1243237 圖5係圖4中所說明之社 心、、。構的剖面圖，該結構具有環繞感 應器之絕緣套管； 圖6係另一晶片類创夕片、^ 、之感應器組態的透視圖，其中該感應 器於氮化鋁（A1N)基板上，|右锋^ 具有溽艇鵡感應器； 圖7係一感應器晶片之简各AA w 、 間化的剖面圖，其中該感應器安裝 於流體導管之内壁； 其中该感應器安 圖8係一感應器之簡化的剖面圖與概圖 裝於流體導管的開口中； 其中該MFM感應器安裝- 圖9a係一 MFM感應器之剖面圖 於導管内部之遮蔽的環境中； 圖9b係沿著圖9a之線段外_外所採取的剖面圖； 圖10係一感應1§之剖面圖，其係根據本發明— 體實* Μ例，其中該感應器浸沒於流體流動的管子中；及For a uniform heat distribution, when a heating current is applied to the tungsten conductor, the tungsten conductor preferably follows a meandering pattern on the substrate 30 and terminates at each end of a pair of spaced contact pads 32. Tungsten provides a high degree of thermal sensitivity, and when used together with aluminum nitride (AlN), it can tolerate a wide temperature range because of the very good temperature expansion coefficients. The thin film tungsten layer is usually about 10-1000 microns thick. This temperature sensor was filed by James D_Parsons, one of the inventors of the present invention, on the same day as this application, and is currently the subject of a pending patent application No. 10 / 6008,737. FIG. 7 illustrates a sensor 34 according to the present invention positioned along the inner wall of the catheter 4. As shown in FIG. The sensor is bonded to the wall in a manner similar to an external sensor, and the material used by the sensor determines whether or not an electrical insulation layer is placed between the sensor and the duct wall. The sensor lead 36 may be led from a position on the distal end of the catheter or directly from an insulating sleeve in the catheter wall. The placement of the sensor in the catheter as described allows very fast and accurate convection of the fluid flowing through the catheter. 93276.doc -14 ·! 243237 Tracking ’but it requires the induction | § or the binding material not to react with the fluid. Referring now to Fig. 8 ', other options for installing the sensor 36 are described, in which the sensor is installed in the opening of the duct wall so that the fluid directly heats its surface facing the interior of the duct. The sensor contact point 38 is located on its outer surface and is easily accessible. The sensor and the opening of the conduit where it is installed should be small enough so that the sensor does not protrude into the conduit, and a good joint can be obtained along its surroundings to secure the sensor in place and avoid fluid loss from the conduit ° As mentioned above, this sensor can be part of a four-element bridge, whether it is an upstream or downstream element of a dual-sensor MFM, or it operates independently with a single-sensor MFM. The current source 12 shown directs current through the inductor and has a voltmeter 40 which monitors the voltage of the inductor in response to the applied current. Comparing the applied current with the measured voltage results in the resistance of the sensor; this can be compared with the resistance when no flow is present, or with the resistance of the upstream or downstream sensors to determine the rate of fluid mass flow in the conduit. In order to prevent the fluid from reacting with the sensor or its bonding material to protect the sensor and / or prevent fluid contamination, the chip-type inductor f 42, shown in Figures and Figures, can be installed inside the protective cover 44, where The cover material forms a closed compartment within the ^ giant 4 to avoid fluid flowing through the catheter. For a stainless steel catheter, the protective cover 44 is preferably stainless steel. Leads 46 may extend upward from the sensor 'through a housing (not shown) in the wall of the catheter. Fig. 10 illustrates an immersion type thermal MFM, in which a wafer-type inductor 48 of a conductor or a thermistor is fixed to the fluid flowing in the conduit 4 and located on the terminal of the ceramic wafer substrate 50. This substrate carries an electronic bow 52 formed by a thin layer of deposited metal 93276.doc -15-1243237, which allows the excitation voltage or current to be applied to the sensor 48 and also allows monitoring of MFM electronic components on the circuit board or at the far end. The resistance of the sensor. FIG. 11 illustrates an MFC using the immersion type] ^ 117] ^ of FIG. 10, which can also use any other specific embodiment of the MFM proposed by the present invention. The flow control valve 54 is located upstream of the immersion sensor 48, and the electronic package 56 monitors the characteristics of the sensor via a lead trace (not shown) on the substrate 50. An electrical interface 58 on the outside of the MFC system housing 60 provides electronic input and output to the system. The electronic component 56 provides a signal to the control valve actuator 62 via the lead 64. One controls the operation of the control valve in response to the detected mass flow rate of the fluid, and allows the flow rate to be maintained at a desired level without being affected upstream or downstream. Disturbance in line pressure or temperature. Although specific embodiments of the invention have been shown and described, those skilled in the art will appreciate that many variations and other specific embodiments are possible. Therefore, it is not intended that the present invention be limited to what is stated in the extended patentable scope. [Schematic description] Figure 1 is a simplified cross-sectional view of a capillary-tube MFM according to the present invention; Figure 2 is a schematic diagram of a four-inductor bridge circuit, which responds to the inductor of Figure 1 and provides MFM output; Series 3 is a graph illustrating the linear relationship between the temperature of the upstream and downstream sensors and the bridge output; Figure 4 is a composite diagram of a perspective view and a schematic diagram of a chip-type temperature sensor. According to the present invention, the chip is The type of temperature sensor is arranged in a bridge state of mfm four sensors; 93276.doc -16- 1243237 Fig. 5 is the social heart, and as explained in Fig. 4. Figure 6 is a perspective view of the sensor configuration of another chip-type Chuang Xi film, ^, and the inductor, which is on an aluminum nitride (A1N) substrate. Upper, right front ^ has a boat sensor, Figure 7 is a simplified cross-sectional view of each sensor chip AA w, where the sensor is installed on the inner wall of the fluid conduit; where the sensor is shown in Figure 8 A simplified cross-sectional view and outline of a sensor are installed in the opening of the fluid conduit; where the MFM sensor is installed-Figure 9a is a sectional view of an MFM sensor in a sheltered environment inside the conduit; Figure 9b is along the Fig. 10 is a cross-sectional view of the induction 1§, which is an example of a physical embodiment according to the present invention, in which the sensor is immersed in a fluid flowing tube; and
圖11係一 MFC系統之簡化的剖面圖，其中該MFc系統且 有本發明之MFM。 ' 0 I 【主要元件符號說明】 2, 4 - 毛細管 6 電子接觸襯塾 8, 10, 12, 14 引線 16-1，16_2 熱傳導層 18 熱傳導接合材料 20-1，20-2, 20-3 鎮鈦（TiW)合金或銻（Ni)層 22-1，22-2, 22-3 金層 24 絕緣套管 93276.doc -17- 1243237 26 接觸襯墊金屬化 28 鎢薄膜 30 絕緣氮化鋁（A1N)基板 32 接觸襯墊 34 感應器 36 感應器引線 38 感應器接觸點 40 電壓計 42, 48 晶片類型感應器 44 保護罩 46, 52, 64 引線 50 陶瓷晶片基板50 54 流動控制閥 56 電子封包 58 接合面 60 外罩 62 控制閥促動器 93276.doc - 18 -Fig. 11 is a simplified cross-sectional view of an MFC system in which the MFc system has the MFM of the present invention. '0 I [Description of main component symbols] 2, 4-Capillary 6 Electronic contact liner 8, 10, 12, 14 Lead 16-1, 16_2 Thermally conductive layer 18 Thermally conductive bonding material 20-1, 20-2, 20-3 Titanium (TiW) alloy or antimony (Ni) layer 22-1, 22-2, 22-3 Gold layer 24 Insulating sleeve 93276.doc -17- 1243237 26 Contact pad metallization 28 Tungsten film 30 Insulating aluminum nitride ( A1N) substrate 32 contact pad 34 sensor 36 sensor lead 38 sensor contact 40 voltmeter 42, 48 chip type sensor 44 protective cover 46, 52, 64 lead 50 ceramic wafer substrate 50 54 flow control valve 56 electronic package 58 Joint surface 60 Housing 62 Control valve actuator 93276.doc-18-