Patent Publication Number: US-2010128155-A1

Title: Image sensors and methods of manufacturing the same

Description:
PRIORITY STATEMENT 
     This application claims the benefit of Korean Patent Application No. 10-2008-0116284 filed on Nov. 21, 2008, the subject matter of which is hereby incorporated in its entirety by reference. 
     BACKGROUND 
     Example embodiments relate to image sensors, and more particularly, to complementary metal oxide semiconductor (CMOS) image sensors and methods of manufacturing the same. 
     Image sensors are devices that convert an optical image into an electrical signal. With recent developments in the computer and communications industries, a demand for CMOS image sensors having improved performance is increasing for various applications such as digital cameras, camcorders, personal communication systems (PCSs), game players, security cameras, medical micro cameras, and robots. 
     CMOS image sensors may include a photo diode for sensing externally-incident light, and a circuit for converting the sensed light into an electrical signal and digitizing the electrical signal. As the amount of light received by the photo diode increases, the photo sensitivity of the CMOS image sensor increases. A CMOS image sensor may include a plurality of photodiodes formed on a semiconductor substrate, a plurality of color filters formed to correspond to the photodiodes in order to pass light in specific wavelength bands (e.g., bandwidths), and a plurality of lenses formed to correspond to the color filters. 
     Light externally incident onto an CMOS image sensor may be focused by the lenses, filtered by the color filters, and fall onto the photo diodes corresponding to the color filters. The CMOS image sensor includes a light guide disposed between the color filters and the photodiodes. The light guide guides light incident from an external source via the lenses and the light is passed through the color filters to fall onto the photo diodes corresponding to the color filters. 
     In conventional CMOS image sensors, the light guide is formed with the same width (for example, a horizontal length) regardless of the types of color filters (e.g., red, green, and blue color filters) or the wavelength and/or range of wavelengths of externally incident light. However, light respectively passed through all channels (e.g., red, green, and blue color filters) of a conventional CMOS image sensor have different wavelengths and/or range of wavelengths, and thus a conventional light guide may not contribute to obtaining highly-efficient and/or improved CMOS image sensors. 
     SUMMARY 
     Example embodiments provide highly-efficient and/or improved image sensors. Example embodiments also provide methods of manufacturing the highly-efficient and/or improved image sensors. 
     According to example embodiments, there is provided an image sensor including a plurality of photoelectric conversion units and a plurality of light guides, at least two of the plurality of light guides having different widths. 
     According to example embodiments, there is also provided a method of manufacturing an image sensor, the method including forming a plurality of photoelectric conversion units and forming a plurality of light guides such that at least two of the plurality of light guides have different widths. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Example embodiments will be more clearly understood from the following brief description taken in conjunction with the accompanying drawings.  FIGS. 1-10  represent non-limiting example embodiments as described herein. 
         FIG. 1  is a circuit diagram of a unit pixel of an image sensor according to an example embodiment; 
         FIG. 2  is a schematic layout of an image sensor according to an example embodiment; 
         FIG. 3  is a cross-sectional diagram illustrating cross-sections taken along lines III-III′ and III′-III″ of  FIG. 2 ; 
         FIGS. 4A and 4B  are graphs of width as a function of optical efficiency, showing the widths of light guides included in the image sensor illustrated in  FIG. 3  as a function of optical efficiency according to a refraction ratio of a material used to form the light guides; and 
         FIG. 5  is a schematic block diagram of an image sensing system including the image sensor illustrated in  FIGS. 2 and 3  according to an example embodiment. 
     
    
    
     It should be noted that these Figures are intended to illustrate the general characteristics of methods, structure and/or materials utilized in certain example embodiments and to supplement the written description provided below. These drawings are not, however, to scale and may not precisely reflect the precise structural or performance characteristics of any given embodiment, and should not be interpreted as defining or limiting the range of values or properties encompassed by example embodiments. For example, the relative thicknesses and positioning of molecules, layers, regions and/or structural elements may be reduced or exaggerated for clarity. The use of similar or identical reference numbers in the various drawings is intended to indicate the presence of a similar or identical element or feature. 
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
     Example embodiments will now be described more fully with reference to the accompanying drawings, in which example embodiments are shown. Example embodiments may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those of ordinary skill in the art. In the drawings, the thicknesses of layers and regions are exaggerated for clarity. Like reference numerals in the drawings denote like elements, and thus their description will be omitted. 
     It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. Like numbers indicate like elements throughout. As used herein the term “and/or” includes any and all combinations of one or more of the associated listed items. Other words used to describe the relationship between elements or layers should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” “on” versus “directly on”). 
     It will be understood that, although the terms “first”, “second”, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of example embodiments. 
     Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated  90  degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     Example embodiments are described herein with reference to cross-sectional illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of example embodiments. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, example embodiments should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an implanted region illustrated as a rectangle may have rounded or curved features and/or a gradient of implant concentration at its edges rather than a binary change from implanted to non-implanted region. Likewise, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface through which the implantation takes place. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of example embodiments. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, such as those defined in commonly-used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     Image sensors according to example embodiments may include a charge coupled device (CCD) image sensor and/or a complementary metal oxide semiconductor (CMOS) image sensor. A CCD generates small noise and provides a high-quality image as compared with the CMOS image sensor. However, a CCD requires a higher voltage and is manufactured at higher costs. A CMOS image sensor is simply driven and can be implemented according to various scanning methods. Because signal processing circuits can be integrated into a single chip, a CMOS image sensor can be made compact. A CMOS image sensor is compatible with CMOS processing techniques, reducing and/or improving the manufacturing costs of CMOS image sensors. A CMOS image sensor consumes very little power and accordingly is easily applied to products that have limits in battery capacity. 
       FIG. 1  is a circuit diagram of a unit pixel  100  of an image sensor according to an example embodiment. Referring to  FIG. 1 , the unit pixel  100  may include a photoelectric conversion unit  110 , a charge detection unit  120 , a charge transmission unit  130 , a reset unit  140 , an amplification unit  150 , and a selection unit  160 . In the present embodiment, a case where the unit pixel  100  includes four transistors is illustrated. However, the unit pixel  100  may include N transistors, where N is a natural number (e.g., 3 or 5). 
     The photoelectric conversion unit  110  may absorb incident light and accumulate charges corresponding to the intensity of radiation. The photoelectric conversion unit  110  may be, for example, a photo diode, a photo transistor, a photo gate, a pinned photo diode (PPD), or a combination thereof. A floating diffusion (FD) region may be used as the charge detection unit  120 . The charge detection unit  120  may receive the accumulated charges from the photoelectric conversion unit  110 . Because the charge detection unit  120  may have parasitic capacitance, charges may be accumulatively stored in the charge detection unit  120 . The charge detection unit  120  may be electrically connected to a gate of the amplification unit  150  and accordingly may control the amplification unit  150 . 
     The charge transmission unit  130  may transmit the charges from the photoelectric conversion unit  110  to the charge detection unit  120 . The charge transmission unit  130  may generally be made up of one transistor and may be controlled by a charge transmission signal TG. The charge transmission signal TG may be transmitted by the charge transmission line  131 . The reset unit  140  may periodically reset the charge detection unit  120  and may be controlled by a reset signal RST. The reset signal RST may be transmitted by a reset line  141 . A source of the reset unit  140  may be connected to the charge detection unit  120 , and a drain thereof may be connected to a power source VDD. The reset unit  140  may be driven in response to a reset signal RST. 
     The amplification unit  150  may be combined with a static current source (not shown) located outside the unit pixel  100  so as to serve as a source follower buffer amplifier. A voltage that varies in response to a voltage of the charge detection unit  120  may be output to a vertical signal line  162 . A source of the amplification unit  150  may be connected to a drain of the selection unit  160 , and a drain of the amplification unit  150  may be connected to the power source VDD. The selection unit  160  may select the unit pixel  100  which is to be read in units of rows and may be controlled by a selection signal ROW. The selection signal ROW may be transmitted by a row line  161 . The selection unit  160  may be driven in response to the selection signal ROW, and a source of the selection unit  160  may be connected to the vertical signal line  162 . The vertical signal line  162  may transmit an output signal Vout. 
     An image sensor  400  according to an example embodiment will now be described with reference to  FIGS. 2 and 3 .  FIG. 2  is a schematic layout of the image sensor  400  according to an example embodiment.  FIG. 3  is a cross-sectional diagram illustrating cross-sections taken along lines III-III′ and III′-III″ of  FIG. 2 . 
     The image sensor  400  according to the present example embodiment may include a plurality of the unit pixels  100  laid out in a matrix form and may convert an optical image into an electrical signal. Light incident from an external source passes through color filters and reaches photoelectric conversion units (e.g., photo diodes). Charges may be accumulated, the charges corresponding to incident light of a wavelength and/or a range of wavelengths in a region. In particular, although the color filters in the present embodiment may be arranged in a Bayer pattern as illustrated in  FIG. 2 , example embodiments are not limited to this arrangement. 
     Referring to  FIGS. 2 and 3 , the image sensor  400  may include a plurality of channels, for example, a first channel, a second channel, and a third channel, on a semiconductor substrate  101 . The first through third pixels may include first through third photoelectric conversion units  110 R,  110 G, and  110 B, first through third light guides  330 R,  330 G, and  330 B, and first through third color filters  340 R,  340 G, and  340 B, respectively. For example, the first channel may include the first photoelectric conversion unit  11  OR within the semiconductor substrate  101 , the first light guide  330 R over the first photoelectric conversion unit  110 R so as to correspond to the first photoelectric conversion unit  110 R, and the first color filter  340 R (e.g., a red color filter) on the first light guide  330 R so as to correspond to the first photoelectric conversion unit  110 R and/or the first light guide  330 R. 
     The second channel may include the second photoelectric conversion unit  110 G within the semiconductor substrate  101 , the second light guide  330 G over the second photoelectric conversion unit  110 G so as to correspond to the second photoelectric conversion unit  110 G, and the second color filter  340 G (e.g., a green color filter) on the second light guide  330 G so as to correspond to the second photoelectric conversion unit  110 G and/or the second light guide  330 G. The third channel may include the third photoelectric conversion unit  110 B within the semiconductor substrate  101 , the third light guide  330 B over the third photoelectric conversion unit  110 B so as to correspond to the third photoelectric conversion unit  110 B, and the third color filter  340 B (e.g., a blue color filter) on the third light guide  330 B so as to correspond to the third photoelectric conversion unit  110 B and/or the third light guide  330 B. 
     The first through third photoelectric conversion units  110 R,  110 G, and  110 B may be separated from one another by isolation regions STI within the semiconductor substrate  101 , and may be adjacent to one another. The isolation regions STI may be in the semiconductor substrate  101  so as to define active regions. The first through third channels may be respectively in the active regions defined by the isolation regions STI. The isolation regions STI may be Field OXide (FOX) or shallow trench isolation (STI) regions which may be formed using a LOCal Oxidation of Silicon (LOCOS) method. 
     The first through third photoelectric conversion units  110 R,  110 G, and  110 B may be in the active regions defined in the semiconductor substrate  101  by the isolation regions STI, and may accumulate charges generated due to absorption of light energy incident from an external source. The first through third photoelectric conversion units  110 R,  110 G, and  110 B may include N-type photo diodes  112 R,  112 G, and  112 B, respectively, and P+-type pinning layers  114 R,  114 G, and  114 B, respectively. 
     On each of the first through third photoelectric conversion units  110 R,  110 G, and  110 B, a charge transmission unit  130  may be located, and transistors corresponding to the charge detection unit  120 , the reset unit  140 , the amplification unit  150 , and the selection unit  160  may be connected. At least one dielectric layer structure  310  (e.g., a dielectric layer structure  310  including at least one layer) may be on the first through third photoelectric conversion units  110 R,  110 G, and  110 B or on the charge transmission units  130  such as to cover the entire surface of the semiconductor substrate  101  and to fill empty spaces. 
     For example, an interlayer dielectric layer  311  may be on the first through third photoelectric conversion units  110 R,  110 G, and  110 B or on the charge transmission units  130  such as to cover the entire surface of the semiconductor substrate  101 . The interlayer dielectric layer  311  may be, for example, an oxide layer or a combination of an oxide layer and a nitride layer. Wiring patterns  320  may be on the interlayer dielectric layer  311 . Each of the wiring patterns  320  may be a single layer or made up of multiple layers (e.g., 2 or 3 layers). In the present example embodiment, each of the wiring patterns  320  may include a first wiring pattern  321  and a second wiring pattern  323 . 
     The first wiring patterns  321  may be on the interlayer dielectric layer  311 . The first wiring patterns  321  may be, for example, aluminum (Al), tungsten (W), or copper (Cu) and may be in peripheral circuit regions. The peripheral circuit regions may denote regions not occupied by channels, for example, regions not occupied by the first through third photoelectric conversion units  110 R,  110 G, and  110 B, on the semiconductor substrate  101 . Regions occupied by the first through third photoelectric conversion units  110 R,  110 G, and  110 B on the semiconductor substrate  101  may be defined as light-receiving regions. 
     A first metal-interlayer dielectric layer  313  may be on the first wiring patterns  321  and/or on the interlayer dielectric layer  311 . The first metal-interlayer dielectric layer  313  may be, for example, an oxide layer and/or a combination of the oxide layer and a nitride layer. The second wiring patterns  323  may be on the first metal-interlayer dielectric layer  313 . The second wiring patterns  323  may be arranged over the first wiring patterns  321  so as to face each other, and may be connected to the first wiring patterns  321  through vias (not shown). The second wiring patterns  323  may be of the same material as the material used to form the first wiring patterns  321  (e.g., Al, W, or Cu). A second metal-interlayer dielectric layer  315  may be on the second wiring patterns  323  or on the first metal-interlayer dielectric layer  313 . The second metal-interlayer dielectric layer  315  may be of the same material as the material used to form the first metal-interlayer dielectric layer  313  (e.g., an oxide layer and/or a combination of the oxide layer and a nitride layer). 
     The first and second metal-interlayer dielectric layers  313  and  315  may be, for example, flowable oxide (FOX), high density plasma (HDP), Tonen SilaZene (TOSZ), spin on glass (SOG), undoped silica glass (USG), or the like. A region of the dielectric layer structure  310 , for example, regions of the interlayer dielectric layer  311  and the first and second metal-interlayer dielectric layers  313  and  315 , may include a plurality of opening regions  317 R,  317 G, and  317 B corresponding to the first through third photoelectric conversion units  110 R,  110 G, and  110 B, respectively. 
     Hereinafter, the opening regions  317 R,  317 G, and  317 B will be referred to as first, second, and third opening regions  317 R,  317 G, and  317 B. Each of the first through third opening regions  317 R,  317 G, and  317 B may be formed by etching the dielectric layer structure  310 , including the interlayer dielectric layer  311  and the first and second metal-interlayer dielectric layers  313  and  315 . The dielectric layer structure  310  may be etched by, for example, wet etching. 
     The first opening region  317 R may extend from the second metal-interlayer dielectric layer  315  to a region over the first photoelectric conversion unit  110 R, for example, to a portion of the interlayer dielectric layer  311  on the first photoelectric conversion unit  110 R. The second opening region  317 G may extend from the second metal-interlayer dielectric layer  315  to a region over the second photoelectric conversion unit  110 G, for example, to a portion of the interlayer dielectric layer  311  on the second photoelectric conversion unit  110 G. The third opening region  317 B may extend from the second metal-interlayer dielectric layer  315  to a region over the third photoelectric conversion unit  110 B, for example, to a portion of the interlayer dielectric layer  311  on the third photoelectric conversion unit  110 B. 
     The first through third opening regions  317 R,  317 G, and  317 B may have regions of the interlayer dielectric layer  311  on the first through third photoelectric conversion units  110 R,  110 G, and  110 B that are exposed (e.g., by etching). The first through third opening regions  317 R,  317 G, and  317 B may have different widths, for example, different horizontal lengths d 1 , d 2 , and d 3 . The first through third light guides  330 R,  330 G, and  330 B may have different widths according to the widths d 1 , d 2 , and d 3  of the first through third opening regions  317 R,  317 G, and  317 B. For example, the width d 1  of the first opening region  317 R may be the same as a width d 1  of the first light guide  330 R, the width d 2  of the second opening region  317 G may be the same as a width d 2  of the second light guide  330 G, and the width d 3  of the third opening region  317 B may be the same as a width d 3  of the third light guide  330 B. 
     The widths d 1 , d 2 , and d 3  of the first through third opening regions  317 R,  317 G, and  317 B may vary according to, for example, a wavelength and/or a range of wavelengths of a first incident light beam A, a wavelength and/or a range of wavelengths of a second incident light beam B, turns, and/or a refraction ratio “n” of a material included in the first through third light guides  330 R,  330 G, and  330 B. The first incident light beam A may be a light beam incident from an external source (e.g., a dedicated light source and/or ambient light). A range of wavelengths of a second incident light beam B may be determined by the passing of the first incident light beam A through one or more of the first through third color filters  340 R,  340 G, and  340 B. A material used to form the first through third light guides  330 R,  330 G, and  330 B may be a light guide material. 
     A range of wavelengths of the first incident light beam A may include all, or less than all, of the wavelengths that may be passed by one of the first through third color filters  340 R,  340 G, and  340 B. For example, the first incident light beam may include half of the wavelengths that may be passed by one of the first through third color filters  340 R,  340 G, and  340 B. The first through third color filters  340 R,  340 G, and  340 B, may pass the second incident light beam B having a wavelength or a range of wavelengths according to the first incident light beam. For example, the second incident light beam B may include half the wavelengths that may be passed by one of the first through third color filters  340 R,  340 G, and  340 B. The widths d 1 , d 2 , and d 3 , may vary according to a wavelength and/or a range of wavelengths of a first incident light beam A, and/or a wavelength and/or a range of wavelengths of a second incident light beam B. The widths d 1 , d 2 , and d 3  may vary based on any number of parameters affecting optical transmission and may be tailored for optimal and/or improved optical efficiency. The widths d 1 , d 2 , and d 3  may be calculated or may be empirically determined. 
       FIGS. 4A and 4B  are graphs of width as a function of optical efficiency, showing the widths d 1 , d 2 , and d 3  of the first through third light guides  330 R,  330 G, and  330 B illustrated in  FIG. 3  as a function of optical efficiency according to the refraction ratio of a material used to form the first through third light guides  330 R,  330 G, and  330 B. 
     Referring to  FIGS. 3 and 4A , when the material used for the first through third light guides  330 R,  330 G, and  330 B has a first refraction ratio n 1  of about 1.57, the width d 1  of the first opening region  317 R (and/or the width of the first light guide  330 R) may be about 0.6 μm in order to obtain optimal and/or improved light efficiency. The width d 2  of the second opening region  317 G (and/or the width of the second light guide  330 G) may be about 0.6 μm in order to obtain optimal and/or improved light efficiency. The width d 3  of the third opening region  317 B (and/or the width of the third light guide  330 B) may be about 0.8 μm in order to obtain optimal and/or improved light efficiency. 
     Referring to  FIGS. 3 and 4B , when the material used for the first through third light guides  330 R,  330 G, and  330 B has a second refraction ratio n 2  of about 1.68, the width d 1  of the first opening region  317 R (and/or the width of the first light guide  330 R) may be about 0.4 μm in order to obtain optimal and/or improved light efficiency. The width d 2  of the second opening region  317 G (and/or the width of the second light guide  330 G) may be about 0.8 μm in order to obtain optimal and/or improved light efficiency. The width d 3  of the third opening region  317 B (and/or the width of the third light guide  330 B) may be about 0.5 μm in order to obtain optimal and/or improved light efficiency. 
     As described above, the widths d 1 , d 2 , and d 3  of the first through third opening regions  317 R,  317 G, and  317 B of the dielectric layer structure  310  (and/or the widths of the first through third light guides  330 R,  330 G, and  330 B) may be set differently according to the refraction ratio of the material used to form the first through third light guides  330 R,  330 G, and  330 B, so that high and/or improved light efficiency may be obtained for each channel. Although the widths d 1 , d 2 , and d 3  of the first through third opening regions  317 R,  317 G, and  317 B of  FIG. 3  are the same as those illustrated in  FIG. 4B , example embodiments are not limited thereto. In  FIGS. 4A and 4B , the X axis may denote the widths d 1 , d 2 , and d 3  of the first through third opening regions  317 R,  317 G, and  317 B (and/or the first through third light guides  330 R,  330 G, and  330 B), and the Y axis may denote light efficiency. 
     Referring to  FIG. 3 , the first through third light guides  330 R,  330 G, and  330 B may be over the first through third photoelectric conversion units  110 R,  110 G, and  110 B so as to face the first through third photoelectric conversion units  110 R,  110 G, and  110 B, respectively. For example, the first through third light guides  330 R,  330 G, and  330 B may be obtained by forming a light guide layer  330  on the first through third opening regions  317 R,  317 G, and  317 B and/or on the second metal-interlayer dielectric layer  315  by using a light guide material (e.g., an oxide-based material). The light guide material may have a higher refraction ratio than a material used to form the dielectric layer structure  310 , namely, the material(s) of the interlayer dielectric layer  311  and the first and second metal-interlayer dielectric layers  313  and  315 . 
     The first through third light guides  330 R,  330 G, and  330 B may entirely reflect externally-incident light. The first incident light beam A or the second incident light beam B may be reflected at least once so that the externally-incident light falls on the first through third photoelectric conversion units  110 R,  110 G, or  110 B adjacent to the externally-incident light. For example, the first light guide  330 R may receive the second incident light beam B incident from an external source via the first color filter  340 R, and may perform at least one entire reflection (e.g., total internal reflection) so that the second incident light beam B falls on the first photoelectric conversion unit  110 R. The second light guide  330 G may perform at least one entire reflection so that the second incident light beam B incident via the second color filter  340 G is received by the second photoelectric conversion unit  110 G. The third light guide  330 B may perform at least one entire reflection so that the second incident light. beam B incident via the third color filter  340 B is received by the third photoelectric conversion unit  110 B. 
     Reflection of incident light may occur because a light guide material(s) used to form the first through third light guides  330 R,  330 G, and  330 B may have a higher refraction ratio than the material used to form the dielectric layer structure  310  adjacent to the first through third light guides  330 R,  330 G, and  330 B. The first through third light guides  330 R,  330 G, and  330 B may be formed, for example, by filling the first through third opening regions  317 R,  317 G, and  317 B, respectively, with a light guide material coated on the second metal-interlayer dielectric layer  315 . 
     The first light guide  330 R may be formed by, for example, filling the first opening region  317 R with a light guide material. One surface of the first light guide  330 R may be adjacent to the first photoelectric conversion unit  110 R, and the other surface thereof may be adjacent to the first color filter  340 R. The first light guide  330 R may guide the second incident light beam B that is passed through the first color filter  340 R to the first photoelectric conversion unit  110 R. 
     The second light guide  330 G may be formed by, for example, filling the second opening region  317 G with a light guide material. One surface of the second light guide  330 G may be adjacent to the second photoelectric conversion unit  110 G, and the other surface thereof may be adjacent to the second color filter  340 G. The second light guide  330 G may guide the second incident light beam B that is passed through the second color filter  340 G to the second photoelectric conversion unit  110 G. 
     The third light guide  330 B may be formed by, for example, filling the third opening region  317 B with a light guide material. One surface of the third light guide  330 B may be adjacent to the third photoelectric conversion unit  110 B, and the other surface thereof may be adjacent to the third color filter  340 B. The third light guide  330 B may guide the second incident light beam B that is passed through the third color filter  340 B to the third photoelectric conversion unit  110 B. 
     As described above, the first through third light guides  330 R,  330 G, and  330 B may have different widths d 1 , d 2 , and d 3 , respectively. For example, the widths d 1 , d 2 , and d 3  of first through third light guides  330 R,  330 G, and  330 B may be the same as the widths d 1 , d 2 , d 3  of the first through third opening regions  317 R,  317 G, and  317 B, respectively. The first through third color filters  340 R,  340 G, and  340 B (e.g., red, green, and blue color filters) may be on the first through third light guides  330 R,  330 G, and  330 B and/or on the light guide layer  330 . 
     The red color filter  340 R (e.g., the first color filter  340 R) may be on the first light guide  330 R. The red color filter  340 R may be at a location that faces the first light guide  330 R and/or the first photoelectric conversion unit  110 R. The green color filter  340 G (e.g., the second color filter  340 G), may be on the second light guide  330 G. The green color filter  340 G may be at a location that faces the second light guide  330 G and/or the second photoelectric conversion unit  110 G. The blue color filter  340 B (e.g., the third color filter  340 B) may be on the third light guide  330 B. The blue color filter  340 B may be at a location that faces the third light guide  330 B and/or the third photoelectric conversion unit  110 B. 
     The first through third color filters  340 R,  340 G, and  340 B may have larger widths than the first through third light guides  330 R,  330 G, and  330 B, respectively. A passivation film  319  may be on the upper surfaces of the first through third color filters  340 R,  340 G, and  340 B. The passivation film  319  may protect structures located under the passivation film  319 , for example, the first through third color filters  340 R,  340 G, and  340 B, the first through third photoelectric conversion units  110 R,  110 G, and  110 B, and the first through third light guides  330 R,  330 G, and  330 B. The passivation film  319  may be of a material that allows externally-incident light (e.g., the first incident light beam A), to easily pass. 
     Micro lenses  350  may be on the passivation film  319  so as to align with the red, green, and blue color filters  340 R,  340 G, and  340 B (e.g., the first through third color filters  340 R,  340 G, and  340 B). The micro lenses  350  may be, for example, TMR-based resin or MFR-based resin. 
       FIG. 5  is a schematic block diagram of an image sensing system  500  including the image sensor  400  described above with reference to  FIGS. 1-4 , according to example embodiments. The image sensing system  500  may be, for example, a computer system, a camera system, a scanner, a mechanized clock system, a navigation system, a video phone, a management system, an auto focusing system, an operation-monitoring system, an image stabilization system, or the like. Various other systems may be used as the image sensing system  500 . 
     Referring to  FIG. 5 , the image sensing system  500 , which may be a computer system, may include a bus  520 , a central processing unit (CPU)  510 , the image sensor  400 , and a memory  530 . Although not shown in  FIG. 5 , the image sensing system  500  may further include an interface that is connected to the bus  520  so as to communicate with the outside. The interface may be an input/output (I/O) interface or a wireless interface. The CPU  510  may generate a control signal for controlling an operation of the image sensor  400 , and provide the control signal to the image sensor  400  via the bus  520 . The image sensor  400  may include, for example, an APS array, a row driver, and an analog-to-digital converter (ADC). The image sensor  400  may sense light according to the control signal provided from the CPU  510  and convert the light into an electrical signal to thereby generate an image signal. The memory  530  may receive the image signal from the image sensor  400  via the bus  520  and store the image signal. The image sensor  400  may be integrated with the CPU  510 , the memory  530 , and the like. In some cases, the image sensor  400  may be integrated with a digital signal processor (DSP), or only the image sensor  400  may be integrated into a separate chip. 
     Provided are image sensors and a methods of manufacturing the image sensors, according to one or more example embodiments, including a plurality of light guides that may be formed to have different widths. Light efficiency of the image sensor with respect to externally incident light may improve. 
     While example embodiments have been particularly shown and described with, it will be understood by one of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the claims.