200810096 二 九、發明說明： 【發明所屬之技術領域】 本發明有關一種影像感測器及其製法，特別是有關一種互補 式金氧半導體電晶體影像感測器及其製法。 【先前技術】 互補式金氧半導體電晶體影像感測器(CMOS image . sensor ’ CIS)和載子偶合裝置(charge-coupled devices，CCDs)都 是習知技術中常用來將光轉換為電子訊號的光學電路元件，兩 者的應用範圍皆很廣泛，包括有掃描器、攝影機、以及照相機 等等’但是因為載子偶合裝置受限於價位高以及體積大的問 題’所以目前市面上以互補式金氧半導體電晶體影像感測器較 為普及。 I 由於互補式金氧半導體電晶體影像感測器是以傳統的半導 體製程製作，因此可以大幅減少所需成本及元件尺寸，而其應 範圍匕括個人電腦相機以及數位相機等數位電子商品，目前 互補式金氧半導體電晶體影像感測器大致分為線型、面型兩 而，型互補式金氧半導體電晶體影像感測器以應用在掃猫 :=等產°"為主’ _互解金氧半導體電晶體影像感測器則以 應用在數位相機等產品為主。 月多考第1圖，第1圖為習知之互補式金氧半導體電晶體 200810096 (CMOS)影像感測器(image sensor) 100之剖面示意圖。如第1 圖所示’影像感測器100包括一像素陣列區1〇2、一光學黑區 (optical black region) 104、及一邏輯區1〇6，分別製作於一半導 體基底110上。半導體基底110包含複數個淺溝隔離(shall〇w trench isolation) 112以及複數個感光二極體U4,各感光二極體 114與至少一相對應之金氧半導體電晶體(未示出）電相連。淺溝 隔離112係用來作為任兩相鄰之感光二極體1M之間的絕緣體 (insulator) 〇 一平坦化層116形成於半導體基底i1Q上，以覆蓋感光二極 體114與淺溝隔離112，接著於平坦化層116上形成圖案化金 屬層118、120、及122。於圖案化金屬層上形成平坦化層124， 平坦化層124可為多層結構，例如由高密度電製(high density plasma)方法製得之氧化矽層（簡稱HDP層)與利用電漿增強式 • 化學氣相沉積方法由乙基正矽酸鹽製得之氧化矽層（簡稱 PETE0S 層（plasma enhanced tetraethyl ortho silicate layer))所組 成。再於平坦化層124上形成保護層(passivation layer) 130，並 沈積頂氧化層132，以防止水氣進入元件區中。 然後’由複數個紅色、綠色、藍色(R/G/B)渡光圖案所構成 • 彩色濾光陣列（colorfllterarray，CFA) 134位於像素陣列區 * :102之頂氧化層132上方。一黑色層136位於光學黑區104之 頂氧化層132上方。並於CFA與黑色層之上及之間形成平坦層 200810096 r 138。並於平坦化層138上方具有複數個微透鏡(micr〇】ens) 140。一頂氧化層142位於最上方，保護微透鏡14〇。位於邏輯 區106的金屬層122則裸露於外部，做為電相連之接合墊。 但是，習知之互補式金氧半導體電晶體影像感測器在製造 時，在製作完成保 m之後，往往使得感光二極體表面上 具有不少的懸空鍵(dangling bond)，而產生漏電流，亦即暗電流 *之問題。習知之解決方式是糊氫氣回火(咖⑽㈣)之方式， 如第2圖所示之回火步驟⑶，使氫原子移動至感光二極體之 表面與懸空鍵反應，以鈍化懸空鍵。但是，由於具有遮光用的 圖案化金屬層120，其金屬會與氫氣反應，妨礙懸空鍵的純化。 因此，仍會產生許多暗電流。 因此’仍需要-觀穎的影像感測元件之結構及製法以解決 φ 暗電流的問題。 、 【發明内容】 的遮光效果 本發明之—目的係提供—種製造影像感瓶件之方法，以料 具有改善之暗電流之影像_元件，並且在絲舰仍具有^好 200810096 u 依據本發明之製造影像感測元件之方法包括下列步驟。首 先’ 供一半導體基底。半導體基底包含有一像素陣列(pixel array)區、一邏輯區、及一光學黑區位於像素陣列區與邏輯區之 間。像素陣列區包括一光感測單元陣列(photo sensing unit array) 及複數個隔離區以隔離各·光感測單元。然後，於半導體基底上 形成一第一平坦化層(planarizedlayer)，覆蓋光感測單元陣列。 _ 於位於像素陣列區及邏輯區之第一平坦化層上形成一圖案化金 屬層。於半導體基底上形成一第二平坦層，且第二平坦化層覆 蓋圖案化金屬層。於低於400°C下，於位於光學黑區之第二平 坦化層上形成一光學黑層。於位於像素陣列區之第二平坦層上 形成一彩色濾光陣列。於光學黑層及彩色濾光陣列上形成一第 —平坦層。於弟二平坦層上形成複數個微透鏡(micr〇iens)，其 中微透鏡係設置於相對應之彩色濾光陣列上方。最後，移除位 於邏輯區之金屬層上方之各層，以曝露位於邏輯區之金屬層以 •做為接合塾。 依據本發明之影像感測元件，包括一半導體基底、一像素陣 列區、一邏輯區、及一光學黑區。像素陣列區係位於半導體基 底上，其包括一光感測單元陣列。邏輯區係位於半導體基底上， \其包括周邊電路。光學黑區係位於半導體基底上之像素陣列區 -與邏輯區之間，其包括一光感測單元位於半導體基底上，一第 平坦化層位於先感測單元上，一第二平坦化層位於第一平挺 化層上，及一光學黑層位於第二平坦化層上。 _ V* 200810096 亀 依據本發明之製造影像感測元件之方法，於光學黑區並不形成 如習知技術所使用之遮光金屬層，而是在形成保護層之後及形成 彩色濾光陣列之前，形成一含有金屬之光學黑層，具有良好遮光 效果。因此於回火以鈍化懸空鍵之製程中，由於沒有習知之遮光 金屬層的阻礙，能夠使光學黑區的懸空鍵鈍化更多，而且，在此 之後可於較低溫度下以包括金屬之材料製作光學黑層，以製得具 有改善之暗電流之影像感測元件。 【實施方式】 請參閱第3圖，第3圖顯示依據本發明之影像感測元件 200。影像感測元件200包括一半導體基底21〇、一像素陣列區 202、一邏輯區206、及一光學黑區2〇4。像素陣列區2〇2係位 於半導體基底210上，包括一光感測單元陣列214。邏輯區200 係位於半導體基底210上，包括周邊電路。光學黑區2〇4係位 於半導體基底上之像素陣列區202與邏輯區206之間，包括一 光感測單元215位於半導體基底2ί〇上、一第一平坦化層216 位於光感測卓元215上、一第二平坦化層224位於第一平坦化 層216上、及一光學黑層236位於第二平坦化層224上。 值付注忍的是’光學黑層236包括一於低溫(例如小於4〇〇〇c) 下製得之金屬層。此金屬層可包括鈦，或是鈦與鈦氮化物之組 合。 200810096 % 光感測單το陣列214可包括感光二極體，其與至少一對應之 金氧半導體電晶體電連接。像素陣列區2〇2除了包括光感測單 元陣列214之外，尚可包括複數個隔離區212以隔離各光感測 單7G，-平坦化層(可為上述第—平坦化層216)覆光感測單 兀陣列214及複數個隔離區212之上；一圖案化金屬層训做 為遮光層位於平坦層上，用以遮光；又一平坦化層覆蓋圖案化 金屬層218，此平坦化層可為多層結構(可為例如上述第二平坦 >化層224);-彩色濾光陣列234位於對應於光感測單元陣列214 之此平坦化層上，及一微透鏡陣列24〇位於彩色濾光陣列 上方。 邏輯區206包括一隔離層213，一平坦化層位於隔離層213 上，圖案化金屬層222做為接合墊位於平坦化層上。平坦化 層可為上述之第一平坦化層216。 請參閱第4至9圖，依據本發明之影像感測元件2〇〇可藉由 下述方法製得。首先，請參閱第4圖，提供一半導體基底21〇， 半導體基底210具有一像素陣列區1〇2、一邏輯區1〇6、及一光 學黑區104位於像素陣列區與邏輯區之間。像素陣列區1〇2包 括一光感測單元陣列214及複數個隔離區212以隔離各光感測 -單元。位於光學黑區104之半導體基底210上具有一光感測單 —元215。邏輯區1〇6之半導體基底上具有一隔離層213。於半導 體基底210上形成一平坦化層216 (planarized layer)，覆蓋各光 12 200810096 感測單兀。平坦化層可藉由沉積方法，形成一介電層再利用 例如化學機_磨，進行平域_得。 接著’請參閱第5圖’於位於像素陣列區1〇2及邏輯區1〇6 之平:L·化層216上形成-圖案化金屬層218及222。圖案化金 屬層218係做為遮光層。圖案化金屬層從係做為接合塾。圖 案化金屬層218及222可藉由濺鍍而形成-金屬層，再利用钕 •刻开)成所需圖案。 請參閱第6圖，再於半導體基底210上形成-平坦化層 224，其覆蓋圖案化金屬層218及222。平坦化層為介電材料， 可為一或多層結構，例如由HDp層226與pETE〇s層所 組成’再將PETEOS層228的頂表面平坦化，而形成平坦化層。 可進-步於平坦化層224上形成一保護層23〇，例如電裝增強 φ 式氮化矽(PE-SiN)層。 然後，請參閱第7圖，經過此等製程，在光感測單元214 及215的感光二極體表面上，易有懸空鍵(danglingb〇nd)產生， 例如mo_。懸空鍵會促使暗電流的產生，影響光量的感 測，亦即影響感光一極體的感測靈敏度。因此，可進行一氫回 火231，或是使用聯胺等其他含氫原子之物質，使氫分子或原 子摻併入平坦化層到達感光二極體表面上與懸空鍵反應，而將 懸空鍵鈍化。值得注意的是，於習知技術中發現，在進行回火 200810096 疇 時ά於光予黑區已存在—大片的金屬遮光層，部分之氨原子 或虱分子可能與金屬反應，而阻礙此部分的氣分子或氣原子前 進至更下層的感光二極面，因此，所製得的域測裝置， 於光學黑區仍有高的暗電流值。此現象於本發明中可獲得明顯 改善，此乃因為在進行回火時，於光學黑區的光感測單元上並 無金屬遮光層存在，因此不會有金屬與氫分子或氫原子進行反 應而阻礙其行進至感光二極體表面的情形發生。因此，懸空鍵 之鈍化完整’ *能夠改善暗電流的問題。 請參閱第8圖’於進行回火後，可進-步於保護層230上形 成-氧化層232 ’例如電漿增強式氧化層，以修復保護層23〇 表面化學結構，但氧化層232並非必需。接著，於氧化層说 ^位於光學黑區之處，形成-光學黑層236。光學黑層236可 藉由於低於上述回火製程之溫度，例如4〇〇〇c之溫度下，進行 鲁金屬濺鑛而形成，亦即形成低溫金屬層，可於低溫下賤鑛而形 成膜的金屬材料均可做為本發明之光學黑層，例如鈦、或欽及 鈦氮化物之組合。接著，可在半導體基底21()上形成一頂氧化 層244 ’覆蓋光學黑層236。使頂氧化層244 #他溫下形成，可 為電聚增強之氧化層’可修復前—製程之濺鑛後受損的表面及 提供保護作用。 接著明參閱第9圖，於位於像素陣列區之平坦層224或是 頂氧化層244(若有軸的話)上形成—彩色就_ 234，即， 14 200810096 龜 m 依序形成紅色濾光陣列、綠色濾光陣列、和藍色濾光陣列於相 對應的感光二極體上方。接著於彩色濾光陣列234及部分光學 黑層上方形成一平坦化層238。然後於平坦化層238上方之相 對應的彩色濾光陣列234之處，形成複數個微透鏡(micr〇lens)。 幵y成微透鏡的方式可藉由形成一由壓克力材料(aerylate material)構成之聚合物層（未顯示），再進行一曝光、顯影以及熱 ，回流(reflow)製程而形成。可進一步於光學黑區及彩色濾光陣列 上形成一平坦層，例如頂氧化層242，以做為表面之保護。 最後’可利用例如蝕刻方法移除邏輯區2 〇 6之圖案化金屬層 222上方之各層，即，平坦化層224、保護層23〇、氧化層232、 及頂氧化層244及242，以曝露出圖案化金屬層222，供電連接 之用’而完成依據本發明之影像感測元件製作。 | 或者’移除邏輯區206之圖案化金屬層222上方之各層之步 驟，可在平坦化層224或是保護層230形成之後，藉由例如光 罩與蝕刻方法進行，移除平坦化層224與保護層23〇。再於最 後頂氧化層242形成之後，移除圖案化金屬層222上方之各層， 使之曝露於外部。 _ 值得注意的是，回火鈍化懸空鍵製程後之各步驟，較佳於較 。回火溫度為低的溫度下進行，例如低於400°C之溫度，如此不 破壞之前鈍化懸空鍵的效果。 200810096 依據本發明之方法製得之影像感測元件具有相對較低之暗 電流。請參閱第1()至21圖，其顯示影像感測元件上各部位之 暗電流量麟果’縱座標是暗電流的量，轉秒電子數_來 表示’橫座標是影像感測元件之行編號。 第10至13圖分賴示習知技術所得之影像感測元件之像素 陣列區、像素陣列區右端之光學黑區、像素陣列區下端之光學 黑區、及影像_元件右下肖之鮮舰之暗電㈣測結果。 此影像感測元件於光學黑區使用金屬遮光層，並於製造時，在 形成金屬遮光層之後，才進行氫氣回火(氫氣：氮氣=0·8 ·· 20 (流 量比)），以消除懸空鍵。第10及12圖之曲線於兩邊明顯翹起， 顯示在邊緣部位之暗電流大，第η至13圖之曲線顯示於光學 黑區测彳于之暗電流之值很大，並且像素陣列區與光學黑區之暗 電流值相差大。 第14至17圖分別顯示習知技術所得之影像感測元件之像素 陣列區、像素陣列區右端之光學黑區、像素陣列區下端之光學 黑區、及影像感測元件右下角之光學黑區之暗電流量測結果。 此影像感測元件於光學黑區使用金屬遮光層，並於製造時，在 形成金屬遮光層之後，才進行氫氣回火(使用較高的氫氣濃度， 氫氣··氮氣=2 ·· 20 (流量比》，以消除懸空鍵。第14及16圖之 曲線於兩邊仍有翹起，顯示在邊緣部位之暗電流仍較大，第15 與17圖之曲線顯示於光學黑區測得之暗電流之值仍在約2000 16 200810096 至4000 e/s之多’並且像素陣列區與光學黑區之暗電流值相差大》 • * · 第18至21圖分別顯示依據本發明所得之影像感測元件之像 素陣列區、像素陣列區右端之光學黑區、像素陣列區下端之光 學黑區、及影像感測元件右下角之光學黑區之暗電流量測結 果。依據本發明之影像感測元件於光學黑區，於製造時，進行 氫氣回火(氫氣：氮氣=2 : 20 (流量比))以消除懸空鍵時，並不 具有金屬遮光層，因此能去除較多的懸空鍵。圖中顯示測得之 暗電流明顯較習知之技術為小。第18與20圖之曲線於兩端已 無明顯的翹起，顯示邊緣處的暗電流與其内部的暗電流並無明 顯差別。而如第19至21圖所示，於光學黑區測得之暗電流之 值已降低至約1〇〇〇至約2000 e/s，並且像素陣列區與光學黑區 之暗電流值之相差減少。可知依據本發明之方法所製得之影像 感測元件可具有改善之暗電流。 以上所述僅為本發明之較佳實施例，凡依本發明申請專利範 圍所做之均等變化與修飾，皆應屬本發明之涵蓋範圍。 【圖式簡單說明】 第1圖為習知之CMOS影像感測器之剖面示意圖。 第2圖顯示習知技術之氫氣回火方法。 第3圖顯示依據本發明之影像感測元件。 第4至9圖顯示依據本發明之影像感測元件之製法。 200810096 第10至21圖顯示習知與依據本發明之影像感測元件上各部位 之暗電流量測結果。200810096 IX. INSTRUCTIONS: [Technical Field] The present invention relates to an image sensor and a method of fabricating the same, and more particularly to a complementary MOS transistor image sensor and a method of fabricating the same. [Prior Art] Complementary MOS transistor image sensor (CMOS). Sensors (CIS) and charge-coupled devices (CCDs) are commonly used in conventional techniques to convert light into electronic signals. Optical circuit components, both of which are used in a wide range of applications, including scanners, cameras, and cameras, but because the carrier coupling device is limited by the high price and large volume, it is currently available on the market. Metal oxide semiconductor crystal image sensors are popular. I Since the complementary MOS transistor image sensor is fabricated in a traditional semiconductor process, it can significantly reduce the cost and component size, including digital computer products such as personal computer cameras and digital cameras. The complementary MOS transistor image sensor is roughly divided into a line type and a surface type. The complementary type MOS transistor crystal image sensor is applied to the sweeping cat: = equal production ° "mainly _ mutual The MOS semiconductor transistor image sensor is mainly applied to products such as digital cameras. FIG. 1 is a cross-sectional view of a conventional complementary MOS transistor 200810096 (CMOS) image sensor 100. As shown in Fig. 1, the image sensor 100 includes a pixel array region 1-2, an optical black region 104, and a logic region 〇6, which are respectively formed on the half of the conductor substrate 110. The semiconductor substrate 110 includes a plurality of shallow trench isolations 112 and a plurality of photodiodes U4. The photodiodes 114 are electrically connected to at least one corresponding MOS transistor (not shown). . The shallow trench isolation 112 is used as an insulator between any two adjacent photodiodes 1M. A planarization layer 116 is formed on the semiconductor substrate i1Q to cover the photodiode 114 and the shallow trench isolation 112. Then, patterned metal layers 118, 120, and 122 are formed on the planarization layer 116. A planarization layer 124 is formed on the patterned metal layer, and the planarization layer 124 can be a multi-layer structure, such as a hafnium oxide layer (HDP layer) obtained by a high density plasma method and a plasma enhanced type. • The chemical vapor deposition method consists of a ruthenium oxide layer (PETO0S layer (plasma enhanced tetraethyl ortho silicate layer). A passivation layer 130 is formed on the planarization layer 124, and a top oxide layer 132 is deposited to prevent moisture from entering the element region. Then 'consisting of a plurality of red, green, blue (R/G/B) light-emitting patterns. • A color filter array (CFA) 134 is located above the top oxide layer 132 of the pixel array region *:102. A black layer 136 is over the top oxide layer 132 of the optical black region 104. A flat layer is formed on and between the CFA and the black layer 200810096 r 138. And a plurality of microlenses ens 140 above the planarization layer 138. A top oxide layer 142 is located at the top to protect the microlens 14〇. The metal layer 122 located in the logic region 106 is exposed to the outside as a bonding pad for electrical connection. However, the conventional complementary MOS transistor image sensor is often made to have a dangling bond on the surface of the photosensitive diode after the fabrication is completed, and a leakage current is generated. That is, the problem of dark current*. The conventional solution is to paste hydrogen gas tempering (Cai (10) (4)). As shown in Fig. 2, the tempering step (3) moves the hydrogen atom to the surface of the photosensitive diode to react with the dangling bond to passivate the dangling bond. However, since the patterned metal layer 120 for light shielding has a metal which reacts with hydrogen gas, the purification of the dangling bonds is hindered. Therefore, many dark currents are still generated. Therefore, the structure and manufacturing method of the image sensing element of the spectator are still needed to solve the problem of φ dark current. OBJECT OF THE INVENTION The present invention is directed to providing a method of manufacturing an image sensing bottle member for imaging an image having an improved dark current, and still having a good sound in the ship: 200810096 u according to the present invention The method of manufacturing an image sensing element includes the following steps. First, a semiconductor substrate is provided. The semiconductor substrate includes a pixel array region, a logic region, and an optical black region between the pixel array region and the logic region. The pixel array region includes a photo sensing unit array and a plurality of isolation regions to isolate the respective light sensing units. Then, a first planarized layer is formed on the semiconductor substrate to cover the photo sensing unit array. Forming a patterned metal layer on the first planarization layer of the pixel array region and the logic region. A second planarization layer is formed on the semiconductor substrate, and the second planarization layer covers the patterned metal layer. An optical black layer is formed on the second planarization layer on the optical black region below 400 °C. A color filter array is formed on the second planar layer of the pixel array region. A first flat layer is formed on the optical black layer and the color filter array. A plurality of microlenses (micr〇iens) are formed on the flat layer of the second brother, wherein the microlens is disposed above the corresponding color filter array. Finally, the layers above the metal layer of the logic region are removed to expose the metal layer in the logic region as the junction. An image sensing device in accordance with the present invention includes a semiconductor substrate, a pixel array region, a logic region, and an optical black region. The pixel array region is on a semiconductor substrate that includes an array of light sensing cells. The logic is located on the semiconductor substrate, which includes peripheral circuitry. The optical black region is located between the pixel array region and the logic region on the semiconductor substrate, and includes a photo sensing unit on the semiconductor substrate, a first planarization layer on the first sensing unit, and a second planarization layer on the second optical layer. On the first flattening layer, and an optical black layer on the second planarizing layer. _ V* 200810096 亀 The method of manufacturing an image sensing element according to the present invention does not form a light-shielding metal layer as used in the prior art in the optical black region, but after forming the protective layer and before forming the color filter array, Forming a metal-containing optical black layer with good light blocking effect. Therefore, in the process of tempering to passivate the dangling bonds, since there is no obstruction of the conventional light-shielding metal layer, the dangling bonds of the optical black region can be more passivated, and thereafter, the material including metal can be used at a lower temperature. An optical black layer is fabricated to produce an image sensing element with improved dark current. [Embodiment] Please refer to Fig. 3, which shows an image sensing element 200 in accordance with the present invention. The image sensing device 200 includes a semiconductor substrate 21, a pixel array region 202, a logic region 206, and an optical black region 2〇4. The pixel array region 2〇2 is located on the semiconductor substrate 210 and includes a photo sensing cell array 214. Logic region 200 is located on semiconductor substrate 210 and includes peripheral circuitry. The optical black area 2〇4 is located between the pixel array area 202 and the logic area 206 on the semiconductor substrate, and includes a light sensing unit 215 on the semiconductor substrate 2, and a first planarization layer 216 in the light sensing element. 215, a second planarization layer 224 is located on the first planarization layer 216, and an optical black layer 236 is located on the second planarization layer 224. The value of the optical black layer 236 includes a metal layer produced at a low temperature (e.g., less than 4 〇〇〇 c). The metal layer may comprise titanium or a combination of titanium and titanium nitride. The 200810096% photo-sensing unit τ array 214 can include a photodiode electrically coupled to at least one corresponding MOS transistor. The pixel array region 2〇2 may include a plurality of isolation regions 212 to isolate the respective light sensing sheets 7G, and the planarization layer (which may be the above-described first planarization layer 216), in addition to the light sensing unit array 214. The light sensing unit array 214 and the plurality of isolation regions 212; a patterned metal layer is disposed as a light shielding layer on the flat layer for shielding; and another planarization layer covers the patterned metal layer 218, and the planarization is performed. The layer may be a multi-layer structure (which may be, for example, the second flat layer 224 described above); the color filter array 234 is located on the planarization layer corresponding to the photo sensing cell array 214, and a microlens array 24 is located Above the color filter array. The logic region 206 includes an isolation layer 213, a planarization layer is disposed on the isolation layer 213, and the patterned metal layer 222 is disposed as a bonding pad on the planarization layer. The planarization layer can be the first planarization layer 216 described above. Referring to Figures 4 through 9, the image sensing element 2 according to the present invention can be obtained by the following method. First, referring to Fig. 4, a semiconductor substrate 21 is provided. The semiconductor substrate 210 has a pixel array region 1-2, a logic region 1-6, and an optical black region 104 between the pixel array region and the logic region. The pixel array area 1 〇 2 includes a photo sensing unit array 214 and a plurality of isolation regions 212 to isolate the respective photo sensing units. A photo sensing unit 215 is disposed on the semiconductor substrate 210 of the optical black area 104. The semiconductor substrate of the logic region 1-6 has an isolation layer 213 thereon. A planarized layer 216 is formed on the semiconductor substrate 210 to cover the respective light 12 200810096 to sense the single turn. The planarization layer can be formed by a deposition method to form a dielectric layer and then, for example, a chemical machine. Next, please refer to FIG. 5 to form patterned metal layers 218 and 222 on the flat: L· layer 216 located in the pixel array region 1〇2 and the logic region 1〇6. The patterned metal layer 218 is used as a light shielding layer. The patterned metal layer is used as a joint. The patterned metal layers 218 and 222 can be formed by sputtering to form a metal layer, which is then engraved into a desired pattern. Referring to FIG. 6, a planarization layer 224 is formed over the semiconductor substrate 210, which covers the patterned metal layers 218 and 222. The planarization layer is a dielectric material, which may be one or more layers, such as composed of HDp layer 226 and pETE(R) layer, and then the top surface of PETEOS layer 228 is planarized to form a planarization layer. A protective layer 23, such as an electrical-enhanced φ-type tantalum nitride (PE-SiN) layer, may be formed on the planarization layer 224. Then, referring to FIG. 7, after the processes, on the surface of the photodiode of the photo sensing units 214 and 215, dangling b〇nd is generated, for example, mo_. The dangling button promotes the generation of dark current, affecting the sensing of the amount of light, that is, the sensing sensitivity of the photosensitive body. Therefore, one hydrogen tempering 231 may be performed, or other hydrogen atom-containing substances such as hydrazine may be used to cause a hydrogen molecule or an atom to be incorporated into the planarization layer to reach the surface of the photosensitive diode to react with the dangling bond, and the dangling bond is Passivation. It is worth noting that, in the prior art, it is found that in the tempering of the 200810096 domain, the luminescence of the black zone has existed - a large metal light-shielding layer, and some of the ammonia atoms or ruthenium molecules may react with the metal, which hinders this part. The gas molecules or gas atoms advance to the lower photosensitive surface, and therefore, the resulting domain measuring device still has a high dark current value in the optical black region. This phenomenon can be significantly improved in the present invention because there is no metal light-shielding layer on the photo-sensing unit of the optical black region during tempering, so that no metal reacts with hydrogen molecules or hydrogen atoms. The situation that hinders its travel to the surface of the photodiode occurs. Therefore, the passivation integrity of the dangling bonds can improve the problem of dark current. Referring to FIG. 8 ' after tempering, an oxide layer 232 ′ may be formed on the protective layer 230, such as a plasma-enhanced oxide layer, to repair the surface chemical structure of the protective layer 23, but the oxide layer 232 is not essential. Next, at the place where the oxide layer is located at the optical black region, an optical black layer 236 is formed. The optical black layer 236 can be formed by performing a metal splattering at a temperature lower than the temperature of the tempering process, for example, 4 〇〇〇c, that is, forming a low-temperature metal layer, which can form a film at a low temperature. The metal material can be used as the optical black layer of the present invention, such as titanium, or a combination of titanium and titanium nitride. Next, a top oxide layer 244' may be formed over the semiconductor substrate 21() to cover the optical black layer 236. The top oxide layer 244 # is formed under temperature, which can be used to protect the damaged surface of the electro-polymerized enhanced oxide layer from the pre-repair process and provide protection. Referring to FIG. 9 , a color _ 234 is formed on the flat layer 224 or the top oxide layer 244 (if any) located in the pixel array region, that is, 14 200810096 turtle m sequentially forms a red filter array, The green filter array and the blue filter array are above the corresponding photodiode. A planarization layer 238 is then formed over the color filter array 234 and a portion of the optical black layer. A plurality of microlenses are then formed at the corresponding color filter array 234 above the planarization layer 238. The method of forming the microlens can be formed by forming a polymer layer (not shown) composed of an aerate material, followed by exposure, development, and heat and reflow processes. A flat layer, such as a top oxide layer 242, may be further formed on the optical black areas and the color filter array to protect the surface. Finally, the layers above the patterned metal layer 222 of the logic region 2 〇6, ie, the planarization layer 224, the protective layer 23, the oxide layer 232, and the top oxide layers 244 and 242, may be removed by, for example, an etching method to expose The patterned metal layer 222 is formed, and the power supply connection is used to complete the image sensing element fabrication according to the present invention. The step of removing the layers above the patterned metal layer 222 of the logic region 206 may be performed after the planarization layer 224 or the protective layer 230 is formed by, for example, a mask and an etching method to remove the planarization layer 224. With the protective layer 23〇. After the formation of the last top oxide layer 242, the layers above the patterned metal layer 222 are removed and exposed to the outside. _ It is worth noting that the steps after the tempering passivation dangling key process are better. The tempering temperature is carried out at a low temperature, for example, a temperature lower than 400 ° C, so that the effect of previously passivating dangling bonds is not destroyed. 200810096 An image sensing element made in accordance with the method of the present invention has a relatively low dark current. Please refer to the first () to 21 figure, which shows the dark current amount of each part on the image sensing element. The ordinate's ordinate is the amount of dark current, and the number of seconds of electrons _ indicates that the 'horizontal coordinate is the image sensing element. Line number. Figures 10 to 13 are based on the pixel array area of the image sensing element obtained by the conventional technique, the optical black area at the right end of the pixel array area, the optical black area at the lower end of the pixel array area, and the fresh ship of the image_component right lower corner Dark electricity (four) test results. The image sensing element uses a metal light-shielding layer in the optical black region, and at the time of manufacture, after the metal light-shielding layer is formed, hydrogen tempering (hydrogen: nitrogen=0·8··20 (flow ratio)) is performed to eliminate Dangling key. The curves of Figures 10 and 12 are obviously lifted on both sides, showing that the dark current is large at the edge portion, and the curves of the η to 13 graphs show that the value of the dark current measured in the optical black region is large, and the pixel array region and The dark current values of the optical black areas differ greatly. The figures 14 to 17 respectively show the pixel array area of the image sensing element obtained by the prior art, the optical black area at the right end of the pixel array area, the optical black area at the lower end of the pixel array area, and the optical black area of the lower right corner of the image sensing element. Dark current measurement results. The image sensing element uses a metal light-shielding layer in the optical black region, and is hydrogen tempered after the metal light-shielding layer is formed at the time of manufacture (using a higher hydrogen concentration, hydrogen··nitrogen=2··20 (flow rate) Ratio to eliminate the dangling key. The curves of Figures 14 and 16 are still tilted on both sides, showing that the dark current is still large at the edge, and the curves of Figures 15 and 17 show the dark current measured in the optical black area. The value is still about 2000 16200810096 to 4000 e/s and the difference between the dark current values of the pixel array region and the optical black region is large. • * · Figures 18 to 21 respectively show the image sensing elements obtained according to the present invention. The dark area measurement result of the pixel array area, the optical black area at the right end of the pixel array area, the optical black area at the lower end of the pixel array area, and the optical black area of the lower right corner of the image sensing element. The image sensing element according to the present invention is In the optical black zone, hydrogen tempering (hydrogen: nitrogen = 2: 20 (flow ratio)) at the time of manufacture eliminates the dangling bond, and does not have a metal light-shielding layer, so that many dangling bonds can be removed. Dark current measured The more conventional technique is small. The curves of Figures 18 and 20 have no obvious tilt at both ends, and the dark current at the edge is not significantly different from the dark current inside. As shown in Figures 19-21, The value of the dark current measured in the optical black region has been reduced to about 1 〇〇〇 to about 2000 e/s, and the difference between the dark current values of the pixel array region and the optical black region is reduced. It is known that the method according to the present invention is The resulting image sensing element can have an improved dark current. The above is only a preferred embodiment of the present invention, and all variations and modifications made to the scope of the present invention should fall within the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view of a conventional CMOS image sensor. Fig. 2 shows a hydrogen tempering method of the prior art. Fig. 3 shows an image sensing element according to the present invention. Figure 9 shows a method of fabricating an image sensing element in accordance with the present invention. 200810096 Figures 10 through 21 show the results of dark current measurements at various locations on conventional image sensing elements in accordance with the present invention.
【主要元件符號說明】 100 習知之CMOS影像感測器 200 依據本發明之影像感測元件 102 、 202 像素陣列區 104 、 204 光學黑區 106、206 邏輯區 110 、 210 半導體基底 112 淺溝隔離 114 感光二極體 116 、 216 平坦化層 118、120、122、 218、222圖案化金蜃層 124 、 224 •平坦化層 126、226 HDP層 128、228 PETEOS 層 130 、 230 保護層 131 回火步驟 132、142、242 、244 頂氧化層 134 、 234 彩色濾光陣列 136、236 光學黑層 138 > 238 平坦化層 18 200810096 140 、 240 微透鏡 212 、 213 隔離區 214 光感測單元陣列 215 光感測單元 231 氫回火 232 氧化雇 19[Major component symbol description] 100 conventional CMOS image sensor 200 image sensing element 102, 202 pixel array area 104, 204 optical black area 106, 206 logic area 110, 210 semiconductor substrate 112 shallow trench isolation 114 in accordance with the present invention Photodiode 116, 216 planarization layer 118, 120, 122, 218, 222 patterned gold germanium layer 124, 224 • planarization layer 126, 226 HDP layer 128, 228 PETEOS layer 130, 230 protective layer 131 tempering step 132, 142, 242, 244 top oxide layer 134, 234 color filter array 136, 236 optical black layer 138 > 238 planarization layer 18 200810096 140 , 240 microlens 212 , 213 isolation region 214 light sensing unit array 215 light Sensing unit 231 hydrogen tempering 232 oxidation hiring 19