201248128 六、發明說明： 【發明所屬之技術領域】 特別是指具三層結構 本發明是一種熱電堆感測元件， 紅外線吸收體之熱電堆感測元件。 【先前技術】 電偶具有相對兩端 可輸出電壓信號， 熱電堆感測元件在主要是由複數熱電偶串聯構成，熱 ’只要該兩端之間有溫度差，熱電偶即 而溫度差越大，熱電偶輸出.的電壓信號 越大；藉由量測熱電偶輸出電壓的大小， 體的溫度，因此熱電堆感測元件可作為量測溫::用… 請參考® 8所示，係揭示美國專利第6949286號的熱 電堆感測元件，其包含有一基板5〇,該基板5〇上形成一 開口朝上的空穴51 ’該基板50上並設有一膜片52且該 膜片52覆蓋該空穴51，該膜片51上形成一熱電偶層 3並於忒熱電偶層53上局部形成一熱吸收層54 ,•其中 熱電偶層53被熱吸收㉟54覆蓋的區域稱為熱接點，未被 熱吸收層54覆蓋的區域稱為冷接點。 當該熱吸收層54吸收紅外線熱能而溫度升高時，係 可將溫度直接傳導至熱電偶層53的熱接點上，因冷接點 未破熱吸收層54覆蓋’此時熱電偶層53於熱接點的溫度 高於冷接點的溫度而產生溫度差，因此熱電偶層53即可 輸出電壓訊號。201248128 VI. Description of the invention: [Technical field to which the invention pertains] In particular, the invention relates to a three-layer structure. The invention is a thermopile sensing element, a thermopile sensing element of an infrared absorber. [Prior Art] The galvanic couple has a voltage signal outputted at opposite ends, and the thermopile sensing element is mainly composed of a plurality of thermocouples in series, and the heat is as long as there is a temperature difference between the two ends, and the thermocouple has a temperature difference. The larger the voltage signal of the thermocouple output. By measuring the output voltage of the thermocouple and the temperature of the body, the thermopile sensing component can be used as the temperature measurement:: Use... The thermopile sensing component of U.S. Patent No. 6,949,286, which comprises a substrate 5?, the substrate 5 is formed with an opening 51 facing upwardly. The substrate 50 is provided with a diaphragm 52 and the diaphragm 52 is covered. The cavity 51, a thermocouple layer 3 is formed on the diaphragm 51, and a heat absorbing layer 54 is partially formed on the 忒 thermocouple layer 53. The region in which the thermocouple layer 53 is covered by the heat absorbing layer 3554 is called a hot junction. The area not covered by the heat absorbing layer 54 is referred to as a cold junction. When the heat absorbing layer 54 absorbs infrared heat energy and the temperature rises, the temperature can be directly transmitted to the hot junction of the thermocouple layer 53 because the cold junction is not covered by the heat absorbing layer 54. At this time, the thermocouple layer 53 The temperature difference between the hot junction and the cold junction creates a temperature difference, so the thermocouple layer 53 can output a voltage signal.
惟’該美國專利案所揭示的# -…· 石夕與金（Au)顆粒混合構成的塊體 201248128 使用】的材料，&法在半導體代工廠裡以廉價的標準製程生 產製造’而需導入特殊的材料製程，導致成本提高。 此外，因該熱吸收層54係額外製作，導致其體積較 大導致熱容增力。’使得與熱容成正比關係的熱反應時間也 隨之增加，因此降低元件的熱反應速度。 【發明内容】 因此本發明的主要目的是提供一種熱電堆感測元件， 使其上的熱吸收層可相容於一般的半導體製程，且可使熱 吸收層的體積薄化以降低熱容。 為達前揭目的，本發明所採用的技術手段係令熱電堆 感測元件包含有： 一基板’具有一空穴； 基底層’係形成在該基板上並覆蓋於該空穴上方； 一熱電偶層’形成在該基底層上，其包含有複數串接 的熱電偶對，各熱電偶對具有相對兩端，一端形成一熱接 點部且位在對應於該空穴上方，另端形成一冷接點部且位 在對應於該基板上方；以及 一红外線吸收體，係設置在該熱電偶層上，並與該複 數熱電偶對的熱接點部構成熱接觸，該紅外線吸收體包含 有： 一第一金屬層； 一介電質層’形成在該第一金屬層上；及 一第二金屬層，形成在該介電質層上。 藉由上述構造’本發明之熱電堆感測元件可達以下功 .201248128 效： 1 ·該紅外線吸收體係一層狀結構，而可在一般電晶體 製私中，以金屬沉積、介電質沉積及蝕刻製程手段完成， 而可以低廉的成本生產製造。 2 _本發明之熱電堆感測元件可依欲吸收紅外線波段的 耑求對應凋整第一、第二金屬層的片電阻值與介電值層 的厚度與折射率等參數，使紅外線吸收體在特定的紅外線 波段有最佳的吸收率，且藉由控制該介電值層的厚度，進 而將紅外線吸收體的體積控制在一定的範圍内，使紅外線 吸收體的熱容降低而縮短紅外線吸收體的熱反應時間。 【實施方式】 。月參考圖1與圖2所示，係揭示本發明的一較佳實施 例，該熱電堆感測元件包含有一基板10、一基底層2〇、 一熱電偶層3 0與一紅外線吸收體4 〇。 該基板1 0具有一空穴1 00。 忒基底層20係形成在該基板1〇上並覆蓋於該空穴 1〇〇上方，其中該基底層2〇可全面覆蓋於空穴1〇〇上 方’或者該基底層20可形成一 μ刻窗口，*局部地覆蓋 在該空穴1〇〇上方。 忒熱電偶層30形成在該基底層2〇上，其包含有複數 串接的熱電偶對300,各熱電偶對3〇〇具有相對兩端，— 端形成一熱接點部321且位在對應於該空穴1〇〇上方另 端形成一冷接點部322且位在對應於該基板上方且i 複數熱電偶對300略呈放射狀排列；各熱電㈣3〇〇包> 201248128 有第熱電偶31與一第二熱電偶32，其中該第一、第 一熱電偶31、32彼此為不同的熱電偶材料製成，該第一熱 電偶31形成在該基底層2〇上，該第二熱電偶32形成在 玄第熱電偶31上且連接另一相鄰熱電偶對3〇〇的第一熱 電偶之上，因此使該複數熱電偶對300構成串接結構；其 中有-熱電偶對300的第二熱電偶32未連接另一相鄰熱電 偶對300的第一熱電偶31，因此使兩相鄰熱電偶對3〇〇彼 刀隔可將该兩熱電偶對定義為一始熱電偶對3〇1與一 末熱電偶對302。 ' .忒紅外線吸收體40係設置在該熱電偶層3〇上，並與 a玄複數熱電偶對細的熱接點部321構成熱接觸。 當紅外線吸收體40吸熱而產生溫度變化時，其熱係 傳導至該熱電偶層3Q的熱接點冑321，使熱接點部321 =溫度相對冷接點冑322的溫度升高而產生溫度差，進而 ，始熱電偶對3〇1與末熱電偶對3〇2輸出電壓訊號，藉由 里測泫電壓訊號的大小，即可推算溫度變化。 '' 丨小·^不緣蛛深吸收體 4 紅外線吸收體40包含有一第一金屬層41、 構，該 質層42與一第二金屬層43,該介電質層42形成在 一金屬層41上，且該第二金屬層43形成在該介電 42上，使該第一金屬層41、介電質層42與第二省 43形成由下而上堆4的結構，其中該第—金屬層 為反射層，而該第二金屬層43具有半透光之特^。 本發明熱電堆感測元件的特點是可針對特定波^ 外線波段設計出高吸收率的紅外線吸收體4〇。請參」 6 201248128 至圖7所示’係揭示紅外線吸收體4〇相對不同紅外線波 長的熱吸收率波形圖，其中橫軸表示紅外線波長（|Jm)，縱 軸表示紅外線吸收體40對應紅外線波長的吸收率。舉例 而言’因熱電堆感測元件通常操作在紅外線波段 8〜14(μΓΠ)，假設欲找出紅外線吸收體4〇在紅外線波段約 在8〜14(μηι)時，平均熱吸收率可達9〇%，以下做了四種 模擬試驗。 如圖4所示，係先將第_、第二金屬層41、43的片 電阻值R「、RS與介電質層42的厚度d預設為一定值，本 實施例中，係將第一金屬層41的片電阻值設定為 1.2(ohm/sq.) ’將該第二金屬層43的片電阻值Rs設定為 377(ohm/sq·)，將該介電質層42的厚度d設定為 1250(nm)’藉由調整介電質層42數種不同的折射率η, 得知介電質層42在何種折射率時，可使紅外線吸收體4〇 在紅外線波段於8〜14(μΓΠ)時達最佳的吸收率。由圖4可 以見及，當介電質層42的折射率設定為2時，該紅外線 吸收體40於紅外線波段約8〜14(pm)時的平均熱吸收率可 達90%，一般作法係將介電質層42的折射率設定為14 以上。 如圖5所示，係先將第一、第二金屬層41、43的片 電阻值R「、Rs與介電質層42的折射率”貝設為一定值， 本實施例中’係將第-金屬| 41 @片電阻值R「設定為 1.2(〇hm/Sq·)，將該第二金屬層43的片電阻值Rs設定為 377(〇hm/Sq·)’將該介電質層42的折射率门設定為2，因 此可藉由調整介電質層42數種不同的厚度d，得知介電質 201248128 在夕少厚度d時，使紅外線吸收體40在紅外線波段 於8〜14(Mm)時達最佳的吸收率。由圖5可以見及，當介 電質層42的厚度d設定為125。(_)時，該紅外線吸收體 40於、，工外線波段約8 i 14加）波 般作㈣將介電„42的厚度d設定; 以上。 同樣地，如圖6所示，在本模擬試驗中，係將第一金 屬層41 W電阻值Rf設定為彳2(Qhm/sq )，將該介電質 M2的折射率定為2,將該介電質層42的厚度d設 定為1250_)，由圖6可以見及’當第二金屬層43的片 電阻值Rs設定為細或獅（Qhm/sq)時，該紅外線吸收 體40於紅外線波段約8至14(μπι)波段的平均熱吸收率可 達90 /〇，般作法係將第二金屬層43的片電阻值Rs設定 為大於 100(〇hm/sq.)。 如圖7所示’在本模擬試驗中，係將第二金屬層43 的片電阻值Rs設定為377(ohm/sq.)，將該介電質層42的 折射率η設定為2 ’將該介電質層42的厚度d設定為 1250(nm)’由圖7可以見及，當第一金屬層的片電阻 值Rr設定為1或l〇(〇hm/sq.)時，該紅外線吸收體4〇於 紅外線波段約8至14(μιτι)波段的平均熱吸收率皆可達 90% ’ 一般作法係將第一金屬層43的片電阻值Rr設定為 小於 200(ohm/sq.) 〇 综合以上所述’該紅外線吸收體40係三層的堆疊结 構’係可在已知的半導體製程中’以金屬沉積、介電質沉 積及钮刻手段完成’而金屬沉積、介電質沉積及钮刻製程 201248128 係目前半導體代工廠可輕易完成，因此可以低廉的成本生 產；另一方面’從該熱感測元件的結構而言，且可依欲吸 收紅外線波段的需求而對應調整該紅外線吸收體4 〇中， 各個組成構件的參數，例如第一、第二金屬層的片電阻值 與介電值層的厚度與折射率等，使紅外線吸收體4 Q在期 望的紅外線波段内具有最佳的吸收率。 【圖式簡單說明】 圖1 :本發明熱電堆感測元件之平面示意圖。 圖2 :本發明熱電堆感測元件之剖視示意圖。 圖3 :紅外線吸收體之剖視圖。 圖4〜圖7:本發明熱電堆感測元件之數種較佳實施例 紅外線波長相對吸收率的曲線圖。 圖8 :以知熱電堆感測元件示意圖。 【主要元件符號說明】 10 基板 100 空穴 20 基底層 30 熱電偶層 300 熱電偶對 301 始熱電偶對 302 末熱電偶對 31 第一熱電偶 32 第二熱電偶 321 熱接點部 322 冷接點部 40 紅外線吸收體 41 第一金屬層 42 介電質層 43 第二金屬層 50 基板 51 空穴 201248128 53熱電偶層 52膜片 54熱吸收層 10However, the material of the block 201248128, which is made up of the mixture of #夕... and the gold (Au) particles disclosed in the U.S. patent, is used in a semiconductor factory to manufacture in a cheap standard process. Importing special material processes leads to increased costs. In addition, since the heat absorbing layer 54 is additionally fabricated, its bulk is increased to cause heat capacity enhancement. The thermal reaction time, which is proportional to the heat capacity, also increases, thus reducing the thermal reaction rate of the element. SUMMARY OF THE INVENTION It is therefore a primary object of the present invention to provide a thermopile sensing element such that the heat absorbing layer thereon is compatible with a typical semiconductor process and the volume of the heat absorbing layer can be thinned to reduce heat capacity. For the purpose of the prior art, the technical means adopted by the present invention is such that the thermopile sensing element comprises: a substrate 'having a cavity; a base layer' formed on the substrate and covering the cavity; a thermocouple a layer 'on the base layer, comprising a plurality of series of thermocouple pairs, each thermocouple pair having opposite ends, one end forming a hot junction portion and being located above the hole, the other end forming a a cold junction portion corresponding to the substrate; and an infrared absorber disposed on the thermocouple layer and in thermal contact with the hot junction portion of the plurality of thermocouple pairs, the infrared absorber comprising a first metal layer; a dielectric layer 'on the first metal layer; and a second metal layer formed on the dielectric layer. According to the above configuration, the thermopile sensing element of the present invention can achieve the following work. 201248128 Effect: 1 · The infrared absorbing system has a layered structure, and can be deposited by metal deposition and dielectric deposition in general transistor manufacturing. And the etching process is completed, and the manufacturing process can be performed at a low cost. 2 _ The thermopile sensing element of the present invention can absorb the infrared band to meet the parameters of the sheet resistance value of the first and second metal layers and the thickness and refractive index of the dielectric layer to make the infrared absorber It has an optimum absorption rate in a specific infrared band, and by controlling the thickness of the dielectric layer, the volume of the infrared absorber is controlled within a certain range, so that the heat capacity of the infrared absorber is lowered to shorten the infrared absorption. The thermal reaction time of the body. [Embodiment] Referring to FIG. 1 and FIG. 2, a preferred embodiment of the present invention is disclosed. The thermopile sensing element comprises a substrate 10, a substrate layer 2, a thermocouple layer 30 and an infrared absorber 4. Hey. The substrate 10 has a cavity 100. The ruthenium substrate layer 20 is formed on the substrate 1 并 and over the hole 1 ,, wherein the substrate layer 2 〇 can completely cover the hole 1 ' above or the base layer 20 can form a μ moment The window, * is partially covered over the hole 1〇〇. A thermocouple layer 30 is formed on the base layer 2, which comprises a plurality of series of thermocouple pairs 300, each thermocouple pair 3 has opposite ends, and the end forms a hot junction portion 321 and is located at Corresponding to the upper end of the hole 1〇〇, a cold junction portion 322 is formed and is located above the substrate and the plurality of thermocouple pairs 300 are arranged radially. Each of the thermoelectric (4) 3 packs has a number of a thermocouple 31 and a second thermocouple 32, wherein the first and first thermocouples 31, 32 are made of different thermocouple materials, and the first thermocouple 31 is formed on the base layer 2? The two thermocouples 32 are formed on the first thermocouple 31 and connected to the first thermocouple of the adjacent thermocouple pair 3, so that the plurality of thermocouple pairs 300 form a tandem structure; wherein there is a thermocouple The second thermocouple 32 of the pair 300 is not connected to the first thermocouple 31 of another adjacent thermocouple pair 300, so that the two adjacent thermocouple pairs can be defined as the first thermocouple pair. Thermocouple pair 3〇1 and a last thermocouple pair 302. The infrared absorber 40 is disposed on the thermocouple layer 3, and is in thermal contact with the thin thermal contact portion 321 of the austempering thermocouple. When the infrared absorbing body 40 absorbs heat to cause a temperature change, the heat is conducted to the hot junction 321 of the thermocouple layer 3Q, so that the temperature of the hot junction portion 321 = temperature relative to the cold junction 322 increases to generate a temperature. Poor, in turn, the initial thermocouple pair 3〇1 and the last thermocouple pair 3〇2 output voltage signal, by measuring the magnitude of the voltage signal, the temperature change can be estimated. The 'infrared absorber 40 includes a first metal layer 41, a texture layer 42 and a second metal layer 43 formed on a metal layer. 41, and the second metal layer 43 is formed on the dielectric 42 such that the first metal layer 41, the dielectric layer 42 and the second province 43 form a structure of the bottom-up stack 4, wherein the first The metal layer is a reflective layer, and the second metal layer 43 has a semi-transmissive property. The thermopile sensing element of the present invention is characterized in that an infrared absorbing body 4 高 having a high absorption rate can be designed for a specific wave band. Please refer to "6 201248128 to Fig. 7" for revealing the heat absorption rate waveform of the infrared absorber 4 〇 with respect to different infrared wavelengths, wherein the horizontal axis represents the infrared wavelength (|Jm), and the vertical axis represents the infrared absorption wavelength of the infrared absorber 40 Absorption rate. For example, 'the thermoelectric stack sensing element is usually operated in the infrared band 8~14 (μΓΠ). If you want to find the infrared absorber 4〇 in the infrared band about 8~14 (μηι), the average heat absorption rate can reach 9〇%, four simulation tests were performed below. As shown in FIG. 4, the sheet resistance values R", RS of the first and second metal layers 41, 43 and the thickness d of the dielectric layer 42 are preset to a certain value. In this embodiment, The sheet resistance value of a metal layer 41 is set to 1.2 (ohm/sq.) 'The sheet resistance value Rs of the second metal layer 43 is set to 377 (ohm/sq·), and the thickness d of the dielectric layer 42 is set. It is set to 1250 (nm)'. By adjusting several different refractive indices η of the dielectric layer 42, when the refractive index of the dielectric layer 42 is known, the infrared absorber 4 can be placed in the infrared band at 8~. The optimum absorption rate is obtained at 14 (μΓΠ). As can be seen from Fig. 4, when the refractive index of the dielectric layer 42 is set to 2, the infrared absorber 40 is about 8 to 14 (pm) in the infrared band. The average heat absorption rate can reach 90%, and the general method is to set the refractive index of the dielectric layer 42 to 14 or more. As shown in Fig. 5, the sheet resistance values R of the first and second metal layers 41 and 43 are first. "The refractive index of Rs and the dielectric layer 42" is set to a constant value. In the present embodiment, the first metal|41 @ sheet resistance value R is set to 1.2 (〇hm/Sq·), and Sheet resistance value R of the second metal layer 43 s is set to 377 (〇hm/Sq·)' to set the refractive index gate of the dielectric layer 42 to 2, so that the dielectric layer 42 can be adjusted by adjusting several different thicknesses d of the dielectric layer 42. When the thickness d is small, the infrared absorber 40 is brought to an optimum absorption ratio in the infrared band at 8 to 14 (Mm). As can be seen from Fig. 5, the thickness d of the dielectric layer 42 is set to 125. In the case of (_), the infrared absorbing body 40 is set to be in the range of about 8 i 14 in the outer line, and the thickness d of the dielectric „42 is set. Similarly, as shown in FIG. 6, in the simulation test, the first metal layer 41 W resistance value Rf is set to 彳 2 (Qhm / sq), and the dielectric M2 refractive index is set to 2, The thickness d of the dielectric layer 42 is set to 1250_). As can be seen from FIG. 6, when the sheet resistance value Rs of the second metal layer 43 is set to fine or lion (Qhm/sq), the infrared absorber 40 is The average heat absorption rate in the infrared band of about 8 to 14 (μπι) is up to 90 / 〇. The conventional method is to set the sheet resistance value Rs of the second metal layer 43 to be greater than 100 (〇hm/sq.). As shown in FIG. 7 'In this simulation test, the sheet resistance value Rs of the second metal layer 43 is set to 377 (ohm/sq.), and the refractive index η of the dielectric layer 42 is set to 2 ' The thickness d of the dielectric layer 42 is set to 1250 (nm)'. As can be seen from FIG. 7, when the sheet resistance value Rr of the first metal layer is set to 1 or 1 〇 (〇hm/sq.), the infrared ray The average heat absorption rate of the absorber 4 in the infrared band of about 8 to 14 (μιτι) is up to 90%. The general method is to set the sheet resistance value Rr of the first metal layer 43 to less than 200 (ohm/sq.). 〇Integrally described above, 'the infrared absorber 40 is a three-layer stacked structure' can be completed by metal deposition, dielectric deposition and button etching in a known semiconductor process, and metal deposition, dielectric deposition And the button engraving process 201248128 is currently easily completed by the semiconductor foundry, so it can be produced at low cost; on the other hand, from the structure of the thermal sensing element, the infrared ray can be adjusted according to the demand of the infrared ray band. In the absorber 4, the parameters of each component, such as the first and second gold The sheet resistance value of the genus layer and the thickness and refractive index of the dielectric layer make the infrared absorbing body 4 Q have an optimum absorption rate in the desired infrared ray band. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic plan view of a thermopile sensing element of the present invention. 2 is a schematic cross-sectional view of a thermopile sensing element of the present invention. Fig. 3 is a cross-sectional view of the infrared absorbing body. 4 to 7 are graphs showing the relative absorption rates of infrared wavelengths in several preferred embodiments of the thermopile sensing elements of the present invention. Figure 8: Schematic diagram of the sensing element of the thermopile. [Main component symbol description] 10 substrate 100 hole 20 base layer 30 thermocouple layer 300 thermocouple pair 301 initial thermocouple pair 302 terminal thermocouple pair 31 first thermocouple 32 second thermocouple 321 hot junction portion 322 cold junction Point portion 40 Infrared absorber 41 First metal layer 42 Dielectric layer 43 Second metal layer 50 Substrate 51 Hole 201248128 53 Thermocouple layer 52 Film 54 Heat absorbing layer 10