201143040 六、發明說明： 【發明所屬之技術領域】 本發明係關於一種影像感測器’尤指一種具有降雜訊功能的背面 照光感測器。 【先前技術】 隨著金氧互補(complementary metal-oxide-metal, CMOS)半導體 影像感測器(CMOS image sensor, CIS)中像素尺寸的減小，一感測器 陣列中降低感測效能的各種因素，如：量子效應(quantumefflciency， QE)、串話干擾(crosstalk)以及暗電流(dark current)等，均會變得更加 顯著。對習知影像感測器而言，如：一前面照度感測器(fr〇ntside illuminated sensor) ’每個像素感測器的透鏡均被製造在一基板的一 前面(front side)上。是故，入射光需要穿過金屬層所構成的線路間其 中多層的介電質(dielectric)才能到達-光敏二極體(photodi〇de)，否 則行進中的光會被金屬或其他反射性的物質所吸收或反射。由於光 的行進路線上魏有錢或任何反紐材質，習域·中亦沒有 空間足以容納額外的降雜訊電路。 明“1、第1圖’其為習知前面照度影像感測ϋ陣列中-像素έ士播 之剖面圖。如同第i、'、°構 1圖所不’一入射光行經一微透鏡(micro 201143040 • lens)ML、一彩色濾光片（color filter)CL、多層介電質以及一矽質基 板(silicon substrate)Si ’其中矽質基板Si内具有用以將收集並轉換該 入射光成為電子訊號的一光敏二極體(photo diode)P。一接觸層 (contact layer)C0以及金屬層Ml與M2不可置於該入射光的行進路 線之中’否則光敏二極體P便無法以最有效率的方式運作。因此， 只有極少數的空間能容許使用金屬層來進行布線(t〇uring)，一些功能 性的電路（例如：降雜訊電路、電壓整流電路等）皆難以在這種架 I 構下實現。 【發明内容】 有鑑於此’本發明提供了一種具有一簡易降雜訊元件的背面照光 (backside illuminated，BSI)感測器，其可有效地降低雜訊干擾。 依據本發明之一實施例，其提供了一種背面照光感測器，包含有 • 一基板、至少一透鏡以及至少一像素結構。該基板具有一前面以及 一背面。該透鏡形成於該基板的該背面之上。該像素結構包含有一 第一功率節點、一第二功率節點、一感測元件以及用以降低雜訊之 一電容。該像素結構形成於該基板的該前面上的一像素區域，其中 δ亥像素區域往該基板的一深度方向上的投影區域由該透鏡所覆蓋。 該第一功率節點用以接收一第一供給電壓，而該第二功率節點用以 接收不同於該第一供給電壓之一第二供給電壓。該感測元件用以依 據來自該透鏡的一入射光來產生一感測訊號。該電容包含有一第一 201143040 第一金屬元件、第二金屬元件以及一介電質元件。該第一金屬元件 與該第二金屬元件分別耦接於該第一功率節點與該第二功率節點。 3玄介電負元件則位在该弟一金屬元件以及該第二金屬元件之間。 【實施方式】 請參照第2圖，其為依據本發明之一實施所實現的一背面照光 (backside illuminated，BSI)影像感測器陣列令一像素結構之剖面圖。 如第2圖所示，-入射光行經一财鏡(micr〇lens)ML'一彩色渡光 片(color filteOCL，最後到達一石夕質基板㈣_ _麵卿^的:光 敏二極體(photo diode)P。由於該人射光是_ f基板&的背面所投 射進來，金制Μ卜M2與其他線路均位於韻基板&的另一面 上，故電路的布線也因此有了較大的空間而簡單許多，是故，金屬 層Ml與M2便可應用在改善整體效能之上。 凊參照第3圖，其為依據本發明之一實施例所實現的一像素結構 3〇〇的電路示意圖。像素結構3〇〇形成在基板&之一前面(fr〇nt surface)上的-像素區域ΡΑ±，像素區域伙在往基板&的一深度 ㈣(thickness direction)D上的一投影區域ρΑ，會由微透鏡胤所覆 蓋。像素結構300包含有(但不偏限於）帛以接收一供給電壓wd 的第-功率節點NP、用以接收一接地電壓GN〇的一第二功率節 點NG、一感測兀件31 〇以及耦接於供給電壓VDD與接地電壓gnd 之間的-P争雜訊兀件320。感測元件31〇包含有一重置電晶體㈣的 201143040 transistor)Rx、一輸出電晶體⑽仙紅加耶丨迦)^、四個傳輸電晶體 Txl〜Tx4以及四個分別對應傳輸電晶體Τχ1〜Τχ4的光敏二極體 PD1〜PD4 °重置電晶體Rx具有用以接收一重置指令Srx之一控制 節點、耦接至供給電壓VDD之一第一節點，以及一第二節點。傳 輸電晶體PD 1〜PD 4中料一傳輸電晶體均具有用以接收一傳輸指 令Stx之一控制節點、耦接至重置電晶體之該第二節點之一第一 節點，以及一第二節點。光敏二極體pD1〜pD4中的每一光敏二極 體具有耦接至接地電壓GND之一第一節點，以及耦接至其所對應 的傳輸電aa體之該第二節點的一第二節點。此外，輸出電晶體(在 此貫施例中輸出電晶體SF為一源極隨辆器(source f〇u〇wer))具有 麵接至重置電晶體Rx的該第二節點以及所有傳輸電晶Μχ1〜Τχ4 之該第一節點的一控制節點、耦接至降雜訊元件32〇之一端的一第 -節點，以及用以輸出—感測訊號_的—第二節點。當感測功能 啟動時’光敏二極體pD1〜PD4會接收該入射光並將其轉換為相對 應的電子訊號。傳輸電晶體Τχ1〜Τχ4則由轉輸指令％所啟動，分 別開始將來自相對應光敏二極體Pm〜PD4的電子訊號傳送給輸出 電晶體SF，在此實施例中’輸出電晶體SF是用以作為一緩衝器 (buffer)，並依據傳輸電晶體Τχ1〜Τχ4傳輸的電子訊號總和來輸出感 測訊號Sout給後續的處理裝置。 當傳輸電晶體Τχ1〜Τχ4經過相對應的控制節點接收傳輸指令洳 時’傳輸電晶體Txi〜Tx4會分別傳送光敏二極體pm〜腦所轉換 的電子訊號給輸出電晶體Srx，而輸出電晶體SF會依據傳輸電晶體 201143040201143040 VI. Description of the Invention: [Technical Field] The present invention relates to an image sensor, and more particularly to a backlight sensor having a noise reduction function. [Prior Art] With the reduction of pixel size in a complementary metal-oxide-metal (CMOS) semiconductor image sensor (CIS), various sensor performance reductions in a sensor array Factors such as quantum effect (QE), crosstalk, and dark current become more pronounced. For conventional image sensors, such as a fr〇ntside illuminated sensor, the lens of each pixel sensor is fabricated on a front side of a substrate. Therefore, the incident light needs to pass through a plurality of dielectrics between the lines formed by the metal layer to reach the photodiode (photodi〇de), otherwise the traveling light will be metal or other reflective. Absorbed or reflected by matter. Because there is money or any anti-Buddhist material on the path of light, there is no room for Xiyu·zhong to accommodate additional noise reduction circuits. Ming "1, Fig. 1" is a cross-sectional view of a pixel illuminator in a conventional illuminance image sensing array. As in the i, ', and 1 configuration, an incident light passes through a microlens ( Micro 201143040 • lens) ML, a color filter CL, a multilayer dielectric, and a silicon substrate Si 'where the enamel substrate Si has a function for collecting and converting the incident light into A photodiode P of the electronic signal. A contact layer C0 and metal layers M1 and M2 are not placed in the path of the incident light. Otherwise, the photodiode P cannot be the most Operating in an efficient manner. Therefore, only a very small amount of space allows the use of metal layers for wiring, and some functional circuits (eg, noise reduction circuits, voltage rectifier circuits, etc.) are difficult to In view of the above, the present invention provides a backside illuminated (BSI) sensor with a simple noise reduction component, which can effectively reduce noise interference. One embodiment of the present invention The invention provides a backlight illumination sensor comprising: a substrate, at least one lens and at least one pixel structure. The substrate has a front surface and a back surface. The lens is formed on the back surface of the substrate. The pixel structure a first power node, a second power node, a sensing component, and a capacitor for reducing noise. The pixel structure is formed on a front surface of the substrate, wherein the pixel area is a projection area in a depth direction of the substrate is covered by the lens. The first power node is configured to receive a first supply voltage, and the second power node is configured to receive a second supply different from the first supply voltage The sensing component is configured to generate a sensing signal according to an incident light from the lens. The capacitor includes a first 201143040 first metal component, a second metal component, and a dielectric component. The component and the second metal component are respectively coupled to the first power node and the second power node. 3 And the second metal element. [Embodiment] Please refer to FIG. 2, which is a cross-sectional illumination (BSI) image sensor array realized by one embodiment of the present invention. Fig. 2, as shown in Fig. 2, the incident light passes through a micr〇lens ML' color illuminator (color filteOCL, finally reaches a lithographic substrate (4) _ _ 卿 ^ ^: photosensitive diode ( Photo diode)P. Since the person's light is projected from the back of the _f substrate & the gold Μ M2 and other lines are located on the other side of the substrate & The large space is much simpler, so the metal layers M1 and M2 can be applied to improve overall performance. Referring to Figure 3, there is shown a circuit diagram of a pixel structure 3〇〇 implemented in accordance with an embodiment of the present invention. The pixel structure 3〇〇 is formed on a front surface of the substrate & a pixel region ΡΑ±, and the pixel region is in a projection region ρ of a depth direction D toward the substrate & , will be covered by microlenses. The pixel structure 300 includes, but is not limited to, a first power node NP for receiving a supply voltage wd, a second power node NG for receiving a ground voltage GN , a sensing element 31 , and a coupling The -P between the supply voltage VDD and the ground voltage gnd competes with the noise element 320. The sensing element 31A includes a 201143040 transistor) Rx for resetting the transistor (4), an output transistor (10), a red transfer transistor, and four transfer transistors Tx1 to Tx4 and four corresponding transfer transistors Τχ1~ The photodiode PD1 to PD4 of the Τχ4 reset transistor Rx has a control node for receiving a reset command Srx, a first node coupled to the supply voltage VDD, and a second node. The transmission transistors PD 1 to PD 4 have a transmission transistor having a control node for receiving a transmission command Stx, a first node coupled to the second node of the reset transistor, and a second node. Each of the photodiodes pD1 to pD4 has a first node coupled to the ground voltage GND and a second node coupled to the second node of the corresponding transmission aa body . In addition, the output transistor (in this embodiment, the output transistor SF is a source follower) has the second node that is surface-connected to the reset transistor Rx and all of the transmitted power A control node of the first node of the crystal 1~Τχ4, a first node coupled to one end of the noise reduction component 32, and a second node for outputting a sense signal_. When the sensing function is activated, the photosensitive diodes pD1 to PD4 receive the incident light and convert it into a corresponding electronic signal. The transmission transistors Τχ1 to Τχ4 are activated by the transfer command %, and respectively start transmitting the electronic signals from the corresponding photodiodes Pm to PD4 to the output transistor SF. In this embodiment, the output transistor SF is used. The sensing signal Sout is output to the subsequent processing device as a buffer and according to the sum of the electronic signals transmitted by the transmission transistors Τχ1 to Τχ4. When the transmission transistors Τχ1~Τχ4 receive the transmission command through the corresponding control node, the transmission transistors Txi~Tx4 respectively transmit the electronic signals converted by the photodiode pm~brain to the output transistor Srx, and the output transistor SF will be based on transmission transistor 201143040
Txl〜Τχ4所傳輸的電子訊號總和來輸出感測訊號Sout。當重置電晶 體Rx被啟動時，重置電晶體Rx會強制將輸出電晶體SF的該控制 節點(例如：閘極)停留一預定電位上(在此實施例中，輸出電晶體Sf 之該控制節點上的預定電位為”高電位”)，而感測訊號S〇ut也於是在 被強制停留在一預定數值。 然而，由於輸出電晶體SF在此為一源極隨耦器，在該第一節點 (例如：及極)上任何的電壓抖動均會汙染所輸出的感測訊號3〇如。 對4知的則面照度感測ϋ來說，大部分的空間須保留給人射光行進 之用，在其中加入-降雜訊電路幾乎是不可能的。因此，對習知的 刖面照度感測器而言，從參考電壓(如供給電壓VDD與接地電壓 來的雜訊會影響中輸出電晶體的效能。請再次參照第2 圖，該入射光由基板Sl的該背面投射進來，其中的金屬層與介電質 可以用來提昇祕的效能而不會_龍人射光。舉例來說，第2 圖中的金屬層Ml與M2可經由任意的布線來形成一電容或是形成 其他電路元件。在第3圖中則引進了—降雜訊元件汹，在此實施 例中，降雜訊元件32〇是以一電容來實現，用來提供一簡單而有效 解決供給電壓VDD上的穩制題，並達成降低雜訊的目 私。U，上述結構並_來限制本發鴨 用其他電路來進—步設計較為複雜的結構以達到更佳的t. Γ 外，降雜訊功能的處理對Ια 、> ， 對象也不限疋為來自參考電壓的電源雜訊。 降雜訊元細可以採用許多種架構來加以實現，例如：一金屬 201143040 -氧化物-金屬(metal-oxide-metal，MOM)電容、一金屬-絕緣體-金屬 (metal-insulator-metal，MIM)電容或是上述兩者的結合。為了詳細說 明上述結構’請分別參照第4圖、第5圖以及第6圖。第4圖為依 據本發明之一實施例所實現的降雜訊元件320的結構示意圖，第5 圖為依據本發明之另一實施例所實現的降雜訊元件320的剖面圖， 而第6圖為依據本發明之另一實施例所實現的降雜訊元件32〇的立 體結構示意圖。在第4圖中，降雜訊元件32〇為應用金屬層Ml(或 疋金屬層]VC2)所形成的一指叉(interdigital)電容，在第5圖中，降雜 訊元件320為金屬層Ml、金屬層M2以及其間的一層介電質所形成 的一金屬-絕緣體-金屬(MIM)電容，而在第6圖中，降雜訊元件32〇 為二層金屬層、灌孔(via)以及其間的介電質所構成的一電容。簡單 來說，任何應用至少一金屬層以及介電質與氧化物的背面照光感應 器均落在本發明的範鳴之内。 ’ "丁、上所述，本發明提供了一種具有一降雜訊元件的背面照光感應 益，遠降雜訊號元件可以是金屬_氧化物_金屬電容、金屬絕緣體_ 金屬電容，或是以複數個金屬層與其間的介電層所構成的電容。 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，皆闕本發明之涵蓋範圍。 【圖式簡單說明】 201143040 第1圖為習知前面照度影像感測器陣列中的像素結構的剖面圖。 第2圖為依據本發明之—實施所實現之背面照光影像感測㈣列 的像素結構的剖面圖。 圖 第3圖為依據本發明之—實施例所實現之像素結構的電路示意圖。 ^圖為依據本發明之—實施撕實現之降雜訊元件的結構=意 第5圖為依據本發明之另一實施例所實現之降雜訊元件的剖面圖。 第6圖為依據本發明之另—實施例所實現之降雜訊元件的立體結構 示意圖。 【主要元件符號說明】 300 像素結構 310 感測元件 320 降雜訊元件 ML 微透鏡 CF 彩色濾光片 Ml ' M2 金屬層 CO 接觸層 Si 基板 Txl 〜Tx4 傳輪電晶體 Rx 重置電晶體 SF 輪出電晶體 201143040 P ' PD1-PD4 光敏二極體 NP 第一功率節點 NG 第二功率節點 VDD 供給電壓 GND 接地電壓 Stx 傳輸指令 Srx 重置指令 Sout 感測訊號 參 11The sum of the electronic signals transmitted by Tx1~Τχ4 outputs the sensing signal Sout. When the reset transistor Rx is activated, resetting the transistor Rx forces the control node (eg, the gate) of the output transistor SF to stay at a predetermined potential (in this embodiment, the output transistor Sf) The predetermined potential on the control node is "high potential"), and the sense signal S〇ut is then forced to stay at a predetermined value. However, since the output transistor SF is here a source follower, any voltage jitter on the first node (e.g., the pole) can contaminate the sensed signal 3 output. For the four senses, the illuminance sensor ϋ, most of the space must be reserved for the light to travel, and it is almost impossible to add a noise reduction circuit. Therefore, for the conventional illuminance sensor, the noise from the reference voltage (such as the supply voltage VDD and the ground voltage will affect the performance of the output transistor. Please refer to Figure 2 again, the incident light is The back side of the substrate S1 is projected, wherein the metal layer and the dielectric can be used to enhance the secret performance without the ray of the dragon. For example, the metal layers M1 and M2 in FIG. 2 can be passed through any cloth. The line forms a capacitor or forms other circuit components. In Figure 3, a noise reduction component is introduced. In this embodiment, the noise reduction component 32 is implemented by a capacitor to provide a Simple and effective solution to the stability problem on the supply voltage VDD, and achieve the purpose of reducing noise. U, the above structure and _ to limit the hair of the duck with other circuits to further design a more complex structure to achieve better t. Γ In addition, the processing of the noise reduction function is not limited to the power supply noise from the reference voltage. The noise reduction unit can be implemented by many kinds of architectures, for example: a metal 201143040 -oxide-metal E-metal, MOM) capacitor, metal-insulator-metal (MIM) capacitor or a combination of the two. For the detailed description of the above structure, please refer to Figure 4, Figure 5 and 6 is a block diagram of a noise reduction component 320 implemented in accordance with an embodiment of the present invention, and FIG. 5 is a cross-sectional view of a noise reduction component 320 implemented in accordance with another embodiment of the present invention. 6 is a schematic perspective view of a noise reduction component 32A implemented in accordance with another embodiment of the present invention. In FIG. 4, the noise reduction component 32 is an application metal layer M1 (or a metal layer). An interdigital capacitor formed by VC2). In FIG. 5, the noise reducing component 320 is a metal layer M1, a metal layer M2, and a metal-insulator-metal (MIM formed by a dielectric layer therebetween). Capacitor, and in Figure 6, the noise-reducing component 32 is a capacitor formed by a two-layer metal layer, a via, and a dielectric therebetween. In simple terms, any application of at least one metal layer and Both the dielectric and oxide backlights are in the fanning of the present invention. In the above, the present invention provides a back-illumination sensor having a noise-reducing component, which can be a metal_oxide_metal capacitor, a metal insulator_metal capacitor, or The capacitor is composed of a plurality of metal layers and a dielectric layer therebetween. The above is only a preferred embodiment of the present invention, and all the equivalent changes and modifications made according to the scope of the present invention are as follows. [Simplified illustration] 201143040 Figure 1 is a cross-sectional view of a pixel structure in a conventional front illumination image sensor array. Figure 2 is a back illumination image sensing according to the present invention (4) A cross-sectional view of the column's pixel structure. Figure 3 is a circuit diagram of a pixel structure implemented in accordance with an embodiment of the present invention. The figure shows the structure of the noise reduction element implemented by the tearing according to the present invention. FIG. 5 is a cross-sectional view of the noise reducing element implemented in accordance with another embodiment of the present invention. Fig. 6 is a perspective view showing the three-dimensional structure of the noise reducing element realized in accordance with another embodiment of the present invention. [Main component symbol description] 300 pixel structure 310 sensing element 320 noise reduction component ML microlens CF color filter Ml ' M2 metal layer CO contact layer Si substrate Txl ~ Tx4 transmission transistor Rx reset transistor SF wheel Output transistor 201143040 P 'PD1-PD4 Photodiode NP First power node NG Second power node VDD Supply voltage GND Ground voltage Stx Transfer command Srx Reset command Sout Sense signal Ref 11