KR20030056338A - Image sensor with improved light efficiency and fabricating method of the same - Google Patents
Image sensor with improved light efficiency and fabricating method of the same Download PDFInfo
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- H—ELECTRICITY
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- H01L27/146—Imager structures
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- H—ELECTRICITY
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- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14601—Structural or functional details thereof
- H01L27/14609—Pixel-elements with integrated switching, control, storage or amplification elements
- H01L27/1461—Pixel-elements with integrated switching, control, storage or amplification elements characterised by the photosensitive area
Abstract
Description
본 발명은 이미지센서에 관한 것으로 특히, 광효율을 향상시키기 위한 이미지센서 및 그 제조 방법에 관한 것이다.The present invention relates to an image sensor, and more particularly, to an image sensor and a manufacturing method for improving the light efficiency.
일반적으로, 이미지센서라 함은 광학 영상(Optical image)을 전기 신호로 변환시키는 반도체소자로서, 이중 전하결합소자(CCD : Charge Coupled Device)는 개개의 MOS(Metal-Oxide-Silicon) 캐패시터가 서로 매우 근접한 위치에 있으면서 전하 캐리어가 캐패시터에 저장되고 이송되는 소자이며, CMOS(Complementary MOS; 이하 CMOS) 이미지센서는 제어회로(Control circuit) 및 신호처리회로(Signal processing circuit)를 주변회로로 사용하는 CMOS 기술을 이용하여 화소수만큼 MOS트랜지스터를 만들고 이것을 이용하여 차례차례 출력(Output)을 검출하는 스위칭 방식을 채용하는 소자이다.In general, an image sensor is a semiconductor device that converts an optical image into an electric signal, and a charge coupled device (CCD) has individual metal-oxide-silicon (MOS) capacitors that are very different from each other. A device in which charge carriers are stored and transported in a capacitor while being in close proximity, and a CMOS (Complementary MOS) image sensor is a CMOS technology that uses a control circuit and a signal processing circuit as peripheral circuits. Is a device that employs a switching method that creates MOS transistors by the number of pixels and sequentially detects the output using them.
이러한 다양한 이미지센서를 제조함에 있어서, 이미지센서의 감광도(Photo sensitivity)를 증가시키기 위한 노력들이 진행되고 있는 바, 그 중 하나가 집광기술이다. 예컨대, CMOS 이미지센서는 빛을 감지하는 포토다이오드와 감지된 빛을 전기적 신호로 처리하여 데이터화하는 CMOS 로직회로부분으로 구성되어 있는 바,광감도를 높이기 위해서는 전체 이미지센서 면적에서 포토다이오드의 면적이 차지하는 비율(이를 통상 Fill Factor"라 한다)을 크게 하려는 노력이 진행되고 있다.In manufacturing such various image sensors, efforts are being made to increase the photo sensitivity of the image sensor, and one of them is a light condensing technology. For example, the CMOS image sensor is composed of a photodiode for detecting light and a portion of a CMOS logic circuit for processing the detected light as an electrical signal to make data. In order to increase the light sensitivity, the ratio of the photodiode to the total image sensor area is increased. Efforts have been made to increase (usually referred to as Fill Factor).
이미지 센서는 적,녹,청(Red, Green, Blue)의 칼라필터 어레이(Colour Filter Array; 이하 CFA라 함)를 구비함으로써 각각의 색상을 혼합하여 색상을 구현하도록 한다.The image sensor includes red, green, and blue color filter arrays (hereinafter referred to as CFAs) to mix colors to implement colors.
도 1은 종래기술에 따른 이미지 센서를 도시한 단면도이다.1 is a cross-sectional view showing an image sensor according to the prior art.
도 1을 참조하면 종래의 이미지센서는, 고농도의 P++ 기판과 P-에피층이 적층된 P형 반도체층(Sub)과, 반도체층(Sub) 하부에 형성된 다수의 포토다이오드(PD)와, 포토다이오드(PD) 사이의 반도체층(Sub)에 형성된 STI(Shallow Trench Isolation)형 또는 LOCOS(LOCal Oxidation of Siicon)형의 필드절연막(Fox)과, 필드절연막(Fox)과 포토다이오드(PD) 상부에 형성된 절연막(PMD, Pre-Metal Dielectric)과, 절연막(PMD) 상의 필드절연막(Fox) 상부에 형성된 제1금속배선(M1)과, 제1금속배선(M1)이 형성된 프로파일을 따라 후속 평탄화막 형성에 따른 수분 등에 의한 제1금속배선(M1, Metal line-1)의 특성 열화를 방지하기 위한 금속간절연막(IMD1, Inter Metal Layer-1)과 제1금속배선(M1)에 의해 발생한 단차를 완화하기 위해 포토다이오드(PD) 상부의 타폴로지가 낮은 부분에 평탄화되어 형성된 SOG(Spin On Glass) 계열의 평탄화막(PL, PLanalization Layer)과, 평탄화막(PL) 상에 형성된 금속간절연막(IMD2, Inter Metal Layer-2)과, 금속간 절연막절연막(IMD2) 상의 필드절연막(Fox) 상부에 형성된 제2금속배선(M2)과, 제2금속배선(M2) 상에 형성된 보호막(P, Passivation layer)과, 보호막(P) 상의 포토다이오드(PD)와 오버랩되는 상부에 형성된 칼라필터(CF, Color Filter)와, 칼라필터(CF) 상에 평탄화되어 형성된 평탄화막(OCL, Over Coating Layer)와, 평탄화막(OCL) 상의 포토다이오드(PD) 및 칼라필터(CF)와 오버랩되는 상부에 형성된 마이크로렌즈(ML, MocroLens)와, 마이크로렌즈(ML)를 보호하기 위해 마이크로렌즈(ML)의 곡면을 따라 형성된 마이크로렌즈 보호막(MLP, Microlens Passivation layer)을 구비하여 구성된다.Referring to FIG. 1, a conventional image sensor includes a P-type semiconductor layer Sub on which a high concentration P ++ substrate and a P-epi layer are stacked, a plurality of photodiodes PD formed under the semiconductor layer Sub, and a photo. On the field insulating film Fox of the shallow trench isolation or LOCOS type formed on the semiconductor layer Sub between the diodes PD, on the field insulating film Fox and the photodiode PD. Subsequent planarization films are formed along the formed insulating film PMD, the pre-metal dielectric, the first metal wiring M1 formed on the field insulating film Fox on the insulating film PMD, and the first metal wiring M1 formed thereon. To reduce the step caused by the intermetal insulation layer (IMD1, Inter Metal Layer-1) and the first metal wiring (M1) to prevent deterioration of the characteristics of the first metal wiring (M1, Metal line-1) due to moisture, etc. In order to achieve this, the top of the photodiode (PD) has a flat on the lower part of the SOG (Spin On Glass) A second planarization layer PL, an intermetallic insulation layer IMD2 and intermetallic layer-2 formed on the planarization layer PL, and a second upper portion of the field insulation layer Fox on the intermetallic insulation layer IMD2 A passivation layer (P) formed on the metal line (M2), the second metal line (M2), and a color filter (CF) formed on an upper portion overlapping the photodiode (PD) on the passivation layer (P). And a planarization film (OCL) formed on the color filter CF and planarized on the color filter CF, and a microlens ML formed on an upper portion overlapping the photodiode PD and the color filter CF on the planarization film OCL. , MocroLens, and a microlens passivation layer (MLP) formed along the curved surface of the microlens ML to protect the microlens ML.
전술한 이미지센서는 마이크로렌즈(ML)를 통해 집광된 빛을 하부의 포토다이오드(PD)를 포함하는 광감지영역에서 감지하여 트랜스퍼 게이트를 통해 센싱확산영역으로 전달하는 일련의 메카니즘을 통해 광신호를 전기적인 신호로 변화하게 되는 바, 최대한의 빛을 받아들이는 것이 무엇보다도 우선한다고 할 수 있다.The above-described image sensor detects the light collected through the microlens ML in the light sensing area including the lower photodiode PD and transmits the optical signal through a series of mechanisms that transfer the light to the sensing diffusion area through the transfer gate. As electrical signals change, it is said that receiving the maximum amount of light is the first priority.
그러나, 도시된 'A'와 같이 마이크로렌즈(ML)를 통과한 빛이 포토다이오드(PD) 상부를 아무리 광흡수성이 우수한 물질 또는 박막평탄도를 유지한다 하여도 포토다이오드(PD)에서 100% 흡수하지 못하고 반사하는 빛이 존재하게 된다.However, as shown in 'A', light passing through the microlens ML absorbs 100% of the photodiode PD even if the light absorbing material or thin film flatness maintains the upper portion of the photodiode PD. There is a reflected light.
따라서, 반사되는 빛 만큼 효율이 감소하게 되며, 이러한 반사되는 빛은 이미지센서의 다른 구성요소 예컨대, 제1금속배선(M1) 등에 의해 난반사되어 빛이 들어와서는 안되는 게이트전극 또는 주변회로영역 등에 입사하게 되어 암전류 등의 발생 소스로 작용하여 이미지센서의 성능을 열화시킨다.Therefore, the efficiency is reduced as much as the reflected light, and the reflected light is diffusely reflected by other components of the image sensor, for example, the first metal wiring M1 or the like, and the incident light is incident on the gate electrode or the peripheral circuit region. It acts as a generation source of dark current, thereby degrading the performance of the image sensor.
도 2는 마이크로렌즈를 통과하여 광감지영역으로 입사하는 빛의 경로를 추적한 시뮬레이션 분석도이다.FIG. 2 is a simulation analysis diagram for tracking a path of light passing through a microlens and entering the light sensing region.
도 2에 도시된 'X'와 같이, 광감지영역 상부에 초점이 존재하며, 그 초점 역시 하나의 점 형태로 포커싱(Focusing)된 것이 아닌 일정한 면적을 형성하게 되며, 광감지영역 상부에서 퍼져있음을 알 수 있다.As shown by 'X' in FIG. 2, a focus exists in the upper portion of the light sensing region, and the focus also forms a constant area rather than focusing as a single point, and spreads in the upper portion of the light sensing region. It can be seen.
따라서, 마이크로렌즈를 통해 입사된 빛을 광감지영역에서 최대한 포커싱되도록 하며, 그 빛이 반사되지 않도록 하는 기술이 필요하게 된다.Therefore, there is a need for a technique for focusing light incident through the microlens in the light sensing region and preventing the light from being reflected.
상기와 같은 종래 기술의 문제점을 해결하기 위해 제안된 본 발명은, 광감지영역에 입사되는 빛의 반사를 감소시키며, 포커싱을 극대화시키기에 적합한 이미지센서 및 그 제조 방법을 제공하는데 그 목적이 있다.The present invention proposed to solve the problems of the prior art as described above, the object of the present invention to reduce the reflection of the light incident on the light sensing area, and to provide an image sensor suitable for maximizing focusing and its manufacturing method.
도 1은 종래기술에 따른 이미지 센서를 도시한 단면도,1 is a cross-sectional view showing an image sensor according to the prior art,
도 2는 마이크로렌즈를 통과하여 광감지영역으로 입사하는 빛의 경로를 추적한 시뮬레이션 분석도,FIG. 2 is a simulation analysis diagram for tracking a path of light passing through a microlens and entering the light sensing region; FIG.
도 3a 내지 도 3c는 본 발명의 일실시에에 따른 이미지센서 제조 공정을 도시한 단면도3A to 3C are cross-sectional views illustrating an image sensor manufacturing process according to an embodiment of the present invention.
도 4는 본발명의 일실시예에 따라 형성된 이미지센서를 도시한 단면도4 is a cross-sectional view showing an image sensor formed according to an embodiment of the present invention.
도 5는 도 4의 일부분을 확대한 단면도,5 is an enlarged cross-sectional view of a portion of FIG. 4;
도 6은 도 5의 평면도.6 is a plan view of FIG.
* 도면의 주요부분에 대한 부호의 설명 *Explanation of symbols on the main parts of the drawings
Sub : 반도체층PL, OCL : 평탄화막Sub: semiconductor layer PL, OCL: planarization film
ML : 마이크로렌즈CF : 칼라필터ML: Micro Lens CF: Color Filter
P : 보호막M1, M2 : 금속배선P: Protective film M1, M2: Metal wiring
PD : 포토다이오드RL : 반사층PD: Photodiode RL: Reflective layer
Fox : 필드절연막MLP : 마이크로렌즈 보호막Fox: Field Insulation MLP: Micro Lens Protective Film
PMD, IMD1, IMD2 : 금속간 절연막PMD, IMD1, IMD2: Intermetallic Insulation
상기 목적을 달성하기 위하여 본 발명은, 광감지영역; 상기 광감지영역 상에 배치된 절연막; 및 상기 광감지영역의 중앙부를 오픈시키며 그 주변부를 덮는 구조로 배치되어, 상기 광감지영역에서 반사된 빛을 상기 광감지영역으로 재반사하기 위해 상기 절연막 상에 배치된 반사층을 포함하는 이미지센서를 제공한다.In order to achieve the above object, the present invention, the light sensing region; An insulating film disposed on the light sensing region; And a reflection layer disposed on the insulating layer to open the central portion of the light sensing area and to cover the periphery thereof, so that the light reflected from the light sensing area is reflected back to the light sensing area. to provide.
바람직하게, 본 발명의 상기 반사층은 W, Ti, TiN, Al, Cu, Pt, Ir, Ru, Rb, La, Hf, Ta, Au, Rh, Cr, Ce, Th, Os, V 및 이들의 산화물으로 이루어진 그룹으로부터 선택된 적어도 하나를 포함하는 것을 특징으로 하며,Preferably, the reflective layer of the present invention is W, Ti, TiN, Al, Cu, Pt, Ir, Ru, Rb, La, Hf, Ta, Au, Rh, Cr, Ce, Th, Os, V and oxides thereof Characterized in that it comprises at least one selected from the group consisting of,
상기 반사층은 100Å ∼ 2000Å의 두께인 것을 특징으로 한다.The reflective layer is characterized by having a thickness of 100 kPa to 2000 kPa.
또한 상기 목적을 달성하기 위하여 본 발명은, 광감지영역을 포함하는 반도체층 상에 절연막을 형성하는 단계; 상기 절연막 상에 반사층을 형성하는 단계; 및 상기 반사층을 선택적으로 식각하여, 상기 광감지영역 중앙부를 제외한 주변부에만 남도록 하는 단계를 포함하는 이미지센서 제조 방법을 제공한다.In addition, to achieve the above object, the present invention comprises the steps of forming an insulating film on a semiconductor layer including a light sensing region; Forming a reflective layer on the insulating film; And selectively etching the reflective layer to leave only the peripheral portion except the center of the light sensing region.
본 발명은, 광감지영역의 포커싱되는 부분을 포함한 중앙부를 제외한 주변부를 금속계열의 반사층을 금속간절연막 상부에 형성함으로써, 광감지영역의 초점부분을 제외한 나머지 부분의 빛을 차단하여 포커싱이 퍼지는 것을 방지하며, 광감지영역에서 반사된 빛을 반사막을 통해 다시 광감지영역으로 입사시킴으로써, 광효율을 증대시키는 것을 기술적 특징으로 한다.According to the present invention, by forming a metal-based reflective layer on the intermetallic insulating layer, except for the central portion including the focused portion of the light sensing region, the light is prevented from spreading the focus by blocking light in the remaining portions except the focus portion of the light sensing region. It is characterized by preventing the light reflected from the light sensing area to be incident to the light sensing area through the reflective film, thereby increasing the light efficiency.
이하, 본 발명이 속하는 기술분야에서 통상의 지식을 가진 자가 본 발명의 기술적 사상을 용이하게 실시할 수 있을 정도로 상세히 설명하기 위하여, 본 발명의 가장 바람직한 실시예를 첨부한 도면을 참조하여 설명하는 바, 도 3a 내지 도 3c는 본 발명의 일실시에에 따른 이미지센서 제조 공정을 도시한 단면도이며, 도 4는 본발명의 일실시예에 따라 형성된 이미지센서를 도시한 단면도이며, 도 5는 도 4의 일부분을 확대한 단면도이며, 도 6은 도 5의 평면도이다.DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the technical idea of the present invention. 3A to 3C are cross-sectional views illustrating an image sensor manufacturing process according to an embodiment of the present invention, FIG. 4 is a cross-sectional view showing an image sensor formed according to an embodiment of the present invention, and FIG. An enlarged cross-sectional view of a portion of FIG. 6, which is a plan view of FIG. 5.
도 4를 참조하면, 본 발명의 이미지센서는, 고농도의 P++ 기판과 P-에피층이 적층된 P형 반도체층(Sub)과, 반도체층(Sub) 하부에 형성된 다수의 포토다이오드(PD)와, 포토다이오드(PD) 사이의 반도체층(Sub)에 형성된STI(Shallow Trench Isolation)형 또는 LOCOS(LOCal Oxidation of Siicon)형의 필드절연막(Fox)과, 필드절연막(Fox)과 포토다이오드(PD) 상부에 형성된 절연막(PMD, Pre-Metal Dielectric)과, 절연막(PMD) 상의 필드절연막(Fox) 상부에 형성된 제1금속배선(M1)과, 제1금속배선(M1)이 형성된 프로파일을 따라 후속 평탄화막 형성에 따른 수분 등에 의한 제1금속배선(M1, Metal line-1)의 특성 열화를 방지하기 위한 금속간절연막(IMD1, Inter Metal Layer-1)과 제1금속배선(M1)에 의해 발생한 단차를 완화하기 위해 포토다이오드(PD) 상부의 타폴로지가 낮은 부분에 평탄화되어 형성된 SOG(Spin On Glass) 계열의 평탄화막(PL, PLanalization Layer)과, 평탄화막(PL) 상에 형성된 금속간절연막(IMD2, Inter Metal Layer-2)과, 금속간 절연막절연막(IMD2) 상의 필드절연막(Fox) 상부에 형성된 제2금속배선(M2)과, 제2금속배선(M2) 상에 형성된 보호막(P, Passivation layer)과, 보호막(P) 상의 포토다이오드(PD)와 오버랩되는 상부에 형성된 칼라필터(CF, Color Filter)와, 칼라필터(CF) 상에 평탄화되어 형성된 평탄화막(OCL, Over Coating Layer)와, 평탄화막(OCL) 상의 포토다이오드(PD) 및 칼라필터(CF)와 오버랩되는 상부에 형성된 볼록 또는 오목 구조의 마이크로렌즈(ML, MocroLens)와, 마이크로렌즈(ML)를 보호하기 위해 마이크로렌즈(ML)의 곡면을 따라 형성된 마이크로렌즈 보호막(MLP, Microlens Passivation layer)을 구비하여 구성된다.Referring to FIG. 4, the image sensor of the present invention includes a P-type semiconductor layer Sub, in which a high concentration P ++ substrate and a P-epi layer are stacked, a plurality of photodiodes PD formed under the semiconductor layer Sub, A field insulating film Fox, a shallow trench isolation or LOCOS type formed in the semiconductor layer Sub between the photodiodes PD, a field insulating film Fox and a photodiode PD Subsequent planarization along the profile of the insulating film PMD (Pre-Metal Dielectric) formed on the upper surface, the first metal wiring M1 formed on the field insulating film Fox on the insulating film PMD, and the first metal wiring M1 formed thereon. Step difference caused by intermetal insulation layer (IMD1, Inter Metal Layer-1) and first metal wiring (M1) to prevent deterioration of characteristics of the first metal wiring (M1, Metal line-1) due to moisture due to film formation Spin on glass (SOG) system formed by flattening the lower part of the top of photodiode PD Formed on the planarization layer PL, the intermetallic insulation layer IMD2 and the intermetal layer-2 formed on the planarization layer PL, and the field insulation layer Fox on the intermetallic insulation layer IMD2. Passivation layer (P) formed on the second metal wiring (M2), the second metal wiring (M2), and a color filter (CF, Color Filter) formed on the upper portion overlapping the photodiode (PD) on the protective film (P) ), A planarization film (OCL) formed on the color filter CF to be flattened, and a convex or concave formed at an upper portion overlapping the photodiode PD and the color filter CF on the planarization film OCL. And a microlens passivation layer (MLP) formed along the curved surface of the microlens ML to protect the microlens ML.
여기서, 포토다이오드(PD)의 광 흡수영역 즉, 광감지영역과 오버랩되는 금속간절연막(IMD1) 상에 반사층(RL, Reflection Layer)을 배치하되, 광감지영역의 중앙부를 오픈시키며 그 주변부에 배치되도록 하는 바, 이하 도면부호 'B'를 확대 도시한 도 5 및 도 6을 참조하여 후술한다.Here, a reflection layer RL is disposed on the light absorbing region of the photodiode PD, that is, the intermetallic insulating layer IMD1 overlapping with the light sensing region, but the center portion of the photosensitive region is opened to be disposed at the periphery thereof. The reference numeral 'B' will be described later with reference to FIGS. 5 and 6.
도 5 및 도 6에 도시된 구성은 전술한 바와 같으며, 광감지영역(PD, 사실상 포토다이오드 영역과 동일하므로 동일부호를 사용)의 중앙부가 오픈되도록 광감지영역(PD)과 오버랩되는 금속간 절연막(PMD) 상에 W, Ti, TiN, Al, Cu, Pt, Ir, Ru, Rb, La, Hf, Ta, Au, Rh, Cr, Ce, Th, Os, V 등의 금속 또는 이들의 산화물을 단독 또는 적층으로 이용하여 반사층(RL)을 형성한다.5 and 6 are the same as described above, and the metal overlaps with the photosensitive region PD so that the central portion of the photosensitive region PD (which is substantially the same as the photodiode region and uses the same reference numeral) is opened. Metals such as W, Ti, TiN, Al, Cu, Pt, Ir, Ru, Rb, La, Hf, Ta, Au, Rh, Cr, Ce, Th, Os, V, or oxides thereof on the insulating film PMD Is used alone or in a stack to form the reflective layer RL.
따라서, '가'와 같이 원하지 않는 경로로 입사하는 빛을 '나'와 같이 반사층(RL)이 차단하며, '다'와 같이 광감지영역(PD)에서 반사하는 빛을 '라'와 같이 반사층(RL)에서 재반사하여 광감지영역(PD)으로 입사시킨다.Therefore, the reflective layer RL blocks the light that enters an unwanted path such as 'A' and the reflective layer RL reflects the light reflected from the photosensitive area PD, such as 'D'. The light is re-reflected at (RL) to enter the light sensing area PD.
따라서, 광효율을 증가시킬 수 있으며, 사광에 의한 영향을 방지하여 포커싱을 향상시킬 수 있다.Therefore, the light efficiency can be increased, and the focusing can be improved by preventing the influence of the projection.
전술한 본 발명에 따른 이미지센서의 제조 공정을 도 3a 내지 도 3c를 참조하여 설명한다.The manufacturing process of the image sensor according to the present invention described above will be described with reference to FIGS. 3A to 3C.
먼저, 도 3a에 도시된 바와 같이 반도체층(Sub) 상에 국부적으로 필드절연막(Fox)를 형성한 다음, 필드절연막(Fox)에 접하는 반도체층(Sub) 하부에 포토다이오드(PD) 즉, 베리드 포토다이오드를 형성한 다음, 필드절연막(Fox)이 형성된 프로파일을 따라 절연막(PMD)을 형성한 다음, 절연막(PMD) 상에 반사층(RL)을 형성하는 바, 반사 특성이 우수한 전술한 금속 또는 그 산화물을 이용하여 100Å ∼ 2000Å의 두께로 증착한다.First, as shown in FIG. 3A, a field insulating film Fox is locally formed on the semiconductor layer Sub, and then a photodiode PD, that is, a berry, is formed under the semiconductor layer Sub in contact with the field insulating film Fox. After forming the photodiode, the insulating film PMD is formed along the profile of the field insulating film Fox, and then the reflective layer RL is formed on the insulating film PMD. It deposits in thickness of 100 kV-2000 kV using this oxide.
다음으로, 도 3b에 도시된 바와 같이 포토레지스트를 도포한 다음, 노광 및현상 공정을 통해 포토레지스트 패턴(PR)을 형성하는 바, 반사층(RL)의 광감지영역 즉, 포토다이오드(PD)와 오버랩되는 상부의 광감지영역 주변부를 덮도록 형성한다.Next, as shown in FIG. 3B, the photoresist is coated, and then the photoresist pattern PR is formed through an exposure and development process. As a result, the photosensitive region PD, that is, the photodiode PD, It is formed to cover the periphery of the light sensing region of the upper portion overlapping.
이 때, 광감지영역 중앙부의 바나사층(RL)은 노출된다.At this time, the bar screw layer RL in the center of the light sensing region is exposed.
다음으로, 도 3c에 도시된 바와 같이 포토레지스트 패턴(PR)을 식각마스크로 하여 반사층(RL)을 선택적으로 식각하여 광감지영역(PD)의 중앙부를 제외한 주변부에만 반사층(RL)을 형성한 다음, 포토레지스트 패턴(PR)을 제거한다.Next, as illustrated in FIG. 3C, the reflective layer RL is selectively etched using the photoresist pattern PR as an etch mask to form the reflective layer RL only at the periphery except for the center portion of the photosensitive region PD. The photoresist pattern PR is removed.
계속해서, 금속배선(M1, M2)과 금속간 절연막(IMD1, IMD2)과 칼라필터(CF) 및 마이크로렌즈(ML)을 차례로 형성함으로써, 도 4의 이미지센서 제조가 완료된다.Subsequently, by forming the metal wirings M1 and M2, the intermetallic insulating films IMD1 and IMD2, the color filter CF and the microlens ML in that order, the image sensor manufacture of FIG. 4 is completed.
한편, 본 발명에서 반사층은 금속배선과 겹치는 부분에서는 형성하지 않고 화소어레이영역 이외에 주변회로영역에서도 적용할 수 있다.Meanwhile, in the present invention, the reflective layer may be applied to the peripheral circuit region in addition to the pixel array region without forming the reflective layer.
전술한 본 발명은 절연막 상에 광감지영역의 주변부 만을 오픈시키는 반사층을 추가로 형성함으로써, 포커싱을 향상시키며 반사되는 빛을 재입사하로록 하여 광효율을 향상시킬 수 있으며, 사광에 의한 영향을 최소화하여 암전류 등에 의한 특성 열화를 방지할 수 있음을 실시예를 통해 알아 보았다.The present invention as described above further forms a reflective layer on the insulating film to open only the periphery of the photosensitive region, thereby improving focusing and improving the light efficiency by re-inciding the reflected light, and minimizing the influence of the projection light. It was found through the examples that the deterioration of characteristics due to dark current or the like can be prevented.
본 발명의 기술 사상은 상기 바람직한 실시예에 따라 구체적으로 기술되었으나, 상기한 실시예는 그 설명을 위한 것이며 그 제한을 위한 것이 아님을 주의하여야 한다. 또한, 본 발명의 기술 분야의 통상의 전문가라면 본 발명의 기술 사상의 범위 내에서 다양한 실시예가 가능함을 이해할 수 있을 것이다.Although the technical idea of the present invention has been described in detail according to the above preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.
상술한 본 발명은, 이미지센서의 광효율을 향상시킬 수 있어, 궁극적으로 이미지센서의 성능을 크게 향상시킬 수 있는 탁월한 효과를 기대할 수 있다.The present invention described above can improve the light efficiency of the image sensor, it can be expected to have an excellent effect that can ultimately greatly improve the performance of the image sensor.
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| KR100720482B1 (en) * | 2005-12-09 | 2007-05-22 | 동부일렉트로닉스 주식회사 | Cmos image sensor and method for manufacturing the same |
| KR100745991B1 (en) * | 2006-08-11 | 2007-08-06 | 삼성전자주식회사 | Image sensor and method for fabricating the same |
| KR100871793B1 (en) * | 2007-06-26 | 2008-12-02 | 주식회사 동부하이텍 | Method for manufacturing image sensor |
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| KR100745991B1 (en) * | 2006-08-11 | 2007-08-06 | 삼성전자주식회사 | Image sensor and method for fabricating the same |
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