Image sensors and methods for manufacturing the same

Image sensors according to some embodiments of the inventive concepts may include a pixel array are including a plurality of pixels, a peripheral area adjacent the pixel array unit, and an organic photoelectric converting layer including a first portion positioned on the pixel area and a second portion positioned on the peripheral area. The second portion may be separated from the first portion.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Application No. 10-2017-0002923 filed in the Korean Intellectual Property Office on Jan. 9, 2017, the disclosure of which is hereby incorporated herein by reference in its entirety.

BACKGROUND

The present disclosure relates to image sensors, methods for manufacturing the image sensors, and electronic devices including the image sensors.

Electronic devices, such as a digital camera and a smart phone, having a function of photographing an image may include image sensors. Image sensors may include, for example, a charged coupled device (CCD) image sensor or a complementary metal oxide semiconductor (CMOS) image sensor as a semiconductor device converting optical information into an electric signal. CMOS image sensors are widely used.

Image sensors may include pixels including photoelectric converters and transistors. Signals photoelectrically converted by the photoelectric converters may be processed by the transistors and may be output as pixel signals, and image data may be generated based on the pixel signals.

Recently, demand for high resolution image sensors has increased, and in this respect, a size of a pixel has decreased. In the case of an inorganic photoelectric converter formed in a semiconductor substrate, a light absorption area decreases as a size of a pixel decreases, and thus sensitivity may decrease. Accordingly, an organic photoelectric converter including an organic photoelectric converting layer, which is capable of replacing or supplementing an inorganic photoelectric converter, has been researched.

SUMMARY

The present inventive concepts have been made in an effort to provide an image sensor, which is capable of reducing or possibly preventing damage to an organic photoelectric converting layer during a manufacturing process and degradation of a characteristic of an organic photoelectric converter of a pixel. The present inventive concepts have been made in an effort to provide a method for manufacturing an image sensor, which is capable of forming an organic photoelectric converting layer with a simple manufacturing process and reducing or possibly preventing damage to the organic photoelectric converting layer.

Image sensors according to some embodiments of the inventive concepts may include a pixel array are including a plurality of pixels, a peripheral area adjacent the pixel array unit, and an organic photoelectric converting layer including a first portion positioned on the pixel area and a second portion positioned on the peripheral area. The second portion may be separated from the first portion.

Image sensors according to some embodiments of the present inventive concepts may include an underlying structure that includes a pixel array area and a peripheral area adjacent the pixel array area. The pixel array area may include a plurality of pixels. The image sensors may also include an insulating layer on the pixel array area, and the insulating layer may expose a portion of the peripheral area. The image sensors may further include a first organic photoelectric converting layer on the insulating layer on the pixel array area and a second organic photoelectric converting layer on the portion of the peripheral area. The insulating layer and the first organic photoelectric converting layer may be sequentially stacked on the underlying structure in a vertical direction, and the first organic photoelectric converting layer may be spaced apart from the second organic photoelectric converting layer in the vertical direction.

Image sensors according to some embodiments of the present inventive concepts may include an underlying structure that includes a pixel array area and a peripheral area adjacent the pixel array area. The pixel array area may include a plurality of pixels. The image sensors may also include a first insulating layer on the pixel array area and a second insulating layer on the peripheral area, and the first insulating layer and the second insulating layer may be spaced apart from each other in a horizontal direction and may define a recess therebetween. The image sensors may further include a first organic photoelectric converting layer on the first insulating layer on the pixel array area and a second organic photoelectric converting layer in the recess. The first organic photoelectric converting layer may be spaced apart from the second organic photoelectric converting layer in a vertical direction that is perpendicular to an upper surface of the underlying structure.

Methods for manufacturing an image sensor according to some embodiments of the present inventive concepts may include: preparing a substrate (e.g., a semiconductor substrate) including a pixel array unit, in which a plurality of pixels is positioned, and a peripheral area around the pixel array unit, and depositing a first insulating layer and a second insulating layer, which have different layer qualities (e.g., properties), on a first surface of the substrate; etching the first insulating layer and the second insulating layer by a first etching method to form a first opening of the first and second insulating layers extending along an area around the pixel array unit; additionally etching a portion of the first insulating layer and the second insulating layer around the first opening by using a second etching method to form a second opening of the first insulating layer, and a third opening, which is larger than the second opening, of the second insulating layer; and depositing an organic photoelectric converting material on the substrate to form an organic photoelectric converting layer including a first portion positioned in the pixel array unit and a second portion positioned in the third opening, in which the second portion is separated from the first portion.

DETAILED DESCRIPTION OF THE EMBODIMENTS

As used herein the term “and/or” includes any and all combinations of one or more of the associated listed items. Like reference numbers refer to like elements throughout.

An image sensor1according to example embodiments will be described with reference toFIGS. 1 and 2. First, a structure of the image sensor1in plan view will be schematically described with reference toFIG. 1, and then a structure of a cross-section of the image sensor1will be described in detail with reference toFIG. 2.

FIG. 1is plan view of an image sensor according to example embodiments, andFIG. 2is a cross-sectional view of the image sensor illustrated inFIG. 1taken along the line II-II′.

Referring toFIG. 1, the image sensor1includes a pixel array unit AA and a peripheral area PA adjacent the pixel array unit AA. In some embodiments, the peripheral area PA may surround the pixel array unit AA in plan view, as illustrated inFIG. 1. It will be understood that the pixel array unit AA refers to a pixel array area.

The pixel array unit AA includes a plurality of pixels PX and a plurality of signal lines10and20. The plurality of pixels PX may be arranged in a form of a matrix, and each pixel PX includes at least one photoelectric converter. The plurality of signal lines10and20may include the plurality of first signal lines10extending in a first direction X, and the plurality of second signal lines20extending in a second direction Y traversing the first direction X. In some embodiments, the first direction X crosses the second direction Y and may be perpendicular to the second direction Y. The first signal line10may transmit a driving signal for driving the pixel PX and drive the pixel PX in the unit of a row. The second signal line20may transmit a pixel signal according to charges generated by the photoelectric converter of each pixel PX in response to light incident on each pixel PX. Each pixel PX may be connected to at least one first signal line10and one second signal line20.

The peripheral area PA includes a trench portion OP extending along an outer side of the pixel array unit AA. The trench portion OP may be formed of an opening formed in a plurality of insulating layers (e.g.,130aand130binFIG. 2), which is to be described below. The trench portion OP may have a structure, which extends along the periphery of the pixel array unit AA and surrounds most of the pixel array unit AA. The inventive concepts, however, are not limited thereto. In some embodiments, the trench portion OP may not surround the pixel array unit AA. A width of the trench portion OP in the plan view may be, for example, about 0.5 μm to about 2 μm, but not limited thereto.

Referring toFIG. 2, the image sensor1may include a substrate120(e.g., a semiconductor substrate). The substrate120may be a substrate including, for example, silicon, germanium, silicon-germanium, a Group-VI compound semiconductor, and a Group-V compound semiconductor. The substrate120may be a silicon substrate including impurities having a first conductive type (for example, p-type). In some embodiments, the impurities may be injected into the substrate120by, for example, an implantation process.

The substrate120may include a plurality of photoelectric converters PD, a plurality of conductive plugs121, and a plurality of charge storing units123.

The photoelectric converter PD may be an inorganic photoelectric converter, which is capable of photoelectrically converting incident light and generating charges. Examples of the photoelectric converter PD may include a photodiode, a pinned photodiode, a photogate, and a phototransistor. When the photoelectric converter PD is formed of a photodiode, each photoelectric converter PD may be formed by a pn junction, and may generate a pair of electron and hole in response to incident light and generate charges. In some embodiments, the photoelectric converter PD may be formed by injecting impurities having a second conductive type (for example, n-type) that is opposite to the first conductive type of the impurities included in the substrate120. In some embodiments, the photoelectric converter PD may be formed to include a plurality of doping areas.

Each photoelectric converter PD may receive light of a specific wavelength band (or a specific color) and photoelectrically convert the light. Each pixel PX may include one photoelectric converter PD as illustrated inFIG. 2. In some embodiments, each pixel PX may include a plurality of photoelectric converters. When each pixel PX includes one photoelectric converter PD, the adjacent pixel PX may photoelectrically convert light of different wavelength bands. For example, when one pixel PX includes the photoelectric converter PD, which receives blue light and photoelectrically converts the blue light, the adjacent pixel PX may include the photoelectric converter PD, which receives red light and photoelectrically converts the red light.

The conductive plug121may transmit charges, which are photoelectrically converted in an organic photoelectric converter (e.g., an organic photoelectric converting layer160), which is to be described below, and may extend through the substrate120. An insulating layer122for possibly preventing a short-circuit with the substrate120may be positioned around the conductive plug121. The insulating layer122may include, for example, an inorganic insulating material, such as a silicon oxide (SiOx) and a silicon nitride (SiNx).

One or more insulating layers115and one or more wiring layers110may be disposed on a first surface FS of the substrate120. The one or more insulating layers115may be between the substrate120and the wiring layer110.

The wiring layer110may include a plurality of pixel transistors for reading the charges generated in the photoelectric converter PD as a pixel signal, one or more wires including connection wires111, and one or more interlayer insulating layer.

The insulating layer115may include a pair of conductive connecting units116and117positioned at each pixel PX. The conductive connecting units116and117may include, for example, a metal material, such as tungsten (W), aluminum (Al), copper (Cu). Each of the conductive connecting units116and117may extend through the insulating layer115in a thickness direction of the insulating layer115(e.g., a vertical direction that is perpendicular to a surface of the substrate120). One end of the conductive connecting unit116may be connected to the conductive plug121of the substrate120, and the other end of the conductive connecting unit116may be connected to the connection wire111. One end of the conductive connecting unit117may be connected to the charge storing unit123of the substrate120, and the other end of the conductive connecting unit117may be connected to the connection wire111. Accordingly, the charge storing unit123may be connected to the conductive plug121through the conductive connecting units116and117of the insulating layer115and the connection wire111of the wiring layer110. The charge storing unit123may include a semiconductor area having the second conductive type (for example, n-type). The charge storing unit123may temporarily store the charges photoelectrically converted in the organic photoelectric converter until the charges are read out.

The plurality of insulating layers130is positioned on a second surface BS of the substrate120that is opposite the first surface FS of the substrate120. The plurality of insulating layers130may include an insulating material, such as a silicon oxide (SiOx), a silicon nitride (SiNx), a hafnium oxide (HfOx), and an aluminum oxide (Al2O3). All of the plurality of insulating layers130may include the same material. In some embodiments, the plurality of insulating layers130may include two or more layers including different materials.

The plurality of insulating layers130may include a first insulating layer130a(i.e., an upper insulating layer) and a second insulating layer130b(i.e., a lower insulating layer) which have different layer qualities (e.g. different properties). In some embodiments, the second insulating layer130bis between the first insulating layer130aand the substrate120as illustrated inFIG. 2. For example, a density of the first insulating layer130amay be greater than a density of the second insulating layer130b. Further, the first insulating layer130aand the second insulating layer130bmay be etched at different etching speeds/rates by a specific etching process. Particularly, the first insulating layer130aand the second insulating layer130bmay be etched at different speeds when the first insulating layer130aand the second insulating layer130bare etched by the same wet etching process, and the first insulating layer130amay be etched slower than the second insulating layer130b.

The first insulating layer130aand the second insulating layer130bmay include the same material or different materials. The first insulating layer130aand the second insulating layer130bhaving different layer qualities may be formed by depositing the same insulating material under different deposition process conditions or may be formed by depositing different insulating materials.

When the first insulating layer130aand the second insulating layer130bare adjacent to each other as illustrated, a boundary (e.g., an interface) between the first insulating layer130aand the second insulating layer130bmay be visible or invisible. Further, each of the first insulating layer130aand the second insulating layer130bmay also be formed of a single layer as illustrated or may include a plurality of layers.

Still referring toFIGS. 1 and 2, the first insulating layer130amay include a first opening132a(i.e., an upper portion of the trench portion OP), and the second insulating layer130bmay include a second opening132b(i.e., a lower portion of the trench portion OP). The first opening132aand the second opening132bmay overlap each other in plan view and may be connected in a vertical direction to form the trench portion OP. The first and second openings132aand132bmay extend along an area adjacent an outer side of the pixel array unit AA in the plan view and may surround most of the pixel array unit AA. It will be understood that the substrate120can be considered as an underlying structure under the first insulating layer130aand the second insulating layer130b, and the first and second openings132aand132bmay expose a portion of the substrate120.

As illustrated inFIG. 2, a size of the first opening132aof the first insulating layer130amay be smaller than a size of the second opening132bof the second insulating layer130b, and sides of the first insulating layer130a, which define the first opening132a, may protrude from sides of the second insulating layer130b, which define the second opening132b. Accordingly, the second opening132bmay undercut the first insulating layer130a. In some embodiments, the first opening132amay have a first width WA in the first direction X, the second opening132bmay have a second width WB in the first direction X, and the first width WA is greater than the second width WB, as illustrated inFIG. 2. It will be understood that the first insulating layers130aare spaced apart from each other in the first direction by a first distance (i.e., the first width WA), and the second insulating layers130bare spaced apart from each other in the first direction by the second distance (i.e., the second width WB).

The second insulating layer130bmay also be completely removed under the second opening132bof the second insulating layer130bas illustrated inFIG. 2. In some embodiments, a portion of the second insulating layer130bmay remain under the second opening132b, and the second opening132bmay not expose the substrate120.

AlthoughFIG. 2shows that the first insulating layer130ais the topmost layer of the plurality of insulating layers130, it will be understood that the inventive concepts are not limited thereto. In some embodiments, several layers of the plurality of insulating layers130may be disposed on the first insulating layer130a, and the first insulating layer130ais disposed between the several layers of the plurality of insulating layers130and the substrate120.

The topmost surface of the insulating layer130(e.g., the topmost surface of the first insulating layer130a) may be flat. The topmost surface of the insulating layer130, in some embodiments, may include a plurality of recesses152on the plurality of pixels PX, respectively, as illustrated inFIG. 2and may not be flat.

The plurality of lower electrodes151may be positioned on the insulating layer130. The plurality of lower electrodes151may be positioned so as to correspond to the plurality of pixels PX, respectively. The lower electrodes151may be positioned so as to correspond to the plurality of recesses152of the upper surface of the first insulating layer130a, respectively. Each of the plurality of lower electrodes151may overlap a corresponding one of the plurality of pixels PX and may overlap a corresponding one of the plurality of recesses152in plan view. Upper surfaces of the lower electrodes151and an upper surface of the first insulating layer130amay form a flat surface. In some embodiments, the upper surfaces of the lower electrodes151and an upper surface of the first insulating layer130amay be coplanar as illustrated inFIG. 2.

In some embodiments, the plurality of color filters (not illustrated) may be disposed in the insulating layer130. Further, a reflection preventing layer (not illustrated) may be disposed between the color filter and the substrate120.

The organic photoelectric converting layer160may be on the insulating layer130and the lower electrode151and in the trench portion OP. The organic photoelectric converting layer160may include a first portion160a, which is continuously formed on the pixel array unit AA and is disposed on the insulating layer130, a second portion160b, which is in the trench portion OP, and a third portion160c, which is on the peripheral area PA adjacent an outer side of the trench portion OP and is disposed on the insulating layer130.

The second portion160bof the organic photoelectric converting layer160is separated from the first portion160aof the organic photoelectric converting layer160, and the organic photoelectric converting layer160may not be disposed on a lateral surface of the second opening132bof the second insulating layer130b. That is, the second portion160bis physically separated from the first portion160aand is spaced apart from the first portion160awith an interval. The first portion160amay be spaced apart from the second portion160bin a third direction Z, and a lower surface of the first portion160amay be higher than a lower surface of the second portion160brelative to the upper surface of the substrate120, as illustrated inFIG. 2. The lower surface of the first portion160amay directly contact the first insulating layer130aand the lower surface of the second portion160bmay directly contact the substrate120(i.e., underlying structure).

Most of the first portion160amay be disposed on the pixel array unit AA, and a portion of the first portion160amay be disposed on the peripheral area PA adjacent to the pixel array unit AA. In some embodiments, a portion of the first portion160adisposed on a lateral surface of the first opening132a(i.e., a side of the first insulating layer130a) may be on the peripheral area PA, as illustrated inFIG. 2. In some embodiments, each of the lower electrodes151is disposed outside of a region between the second portion160bof the organic photoelectric converting layer160and the substrate120, as illustrated inFIG. 2. In some embodiments, the second portion160bof the organic photoelectric converting layer160may directly contact the substrate120.

The second portion160bmay extend along the trench portion OP in plan view and may have substantially the same shape as the aforementioned shape of the trench portion OP in plan view. That is, the second portion160bmay extend along the periphery of the pixel array unit AA in plan view, and, in some embodiments, the second portion160bmay surround the pixel array unit AA.

In some embodiments, an edge of the second portion160bmay be aligned with an edge of the first portion160ain plan view, and an opposing edge of the second portion160bmay be aligned with an edge of the third portion160cin plan view. Most of the second portion160bmay be disposed between the first portion160aand the third portion160cin plan view, as illustrated inFIG. 2.

The first portion160aand the third portion160cmay be spaced apart from each other with the trench portion OP interposed therebetween. Each of the first portion160aand the third portion160cmay include a portion on a lateral surface of the first insulating layer130a, which define the first opening132aof the trench portion OP, and a thickness of this portion (i.e., a thickness in the first direction X) may be smaller than a thickness of a portion (i.e., a thickness of the third direction Z) on the upper surface of the first insulating layer130a. It will be understood that an upper surface of an element refer to a surface substantially parallel to the upper surface of the substrate120, and the element also include a lower surface opposite the upper surface and a lateral surface extending between the upper surface and the lower surface. Unlike the illustration, in some embodiments, the organic photoelectric converting layer160may not be disposed on the lateral surface of the first insulating layer130adefining the first opening132aof the first insulating layer130a.

The third portion160cincludes a lateral surface defining a part of an outer boundary surface EL outside of the pixel array unit AA. The organic photoelectric converting layer160may be removed from and thus may not be present outside of the outer boundary surface EL on the peripheral area PA. Referring again toFIG. 1, the outer boundary surface EL may be on the peripheral area PA, may extend along the periphery of the pixel array unit AA, and, in some embodiments, may surround the pixel array unit AA. The outer boundary surface EL may also extend along the outer periphery of the trench portion OP as illustrated inFIG. 1. In some embodiments, the outer boundary surface EL may extend while overlapping the trench portion OP. Referring again toFIG. 2, the outer boundary surface EL may be substantially vertical to the upper surface of the substrate120in the cross-sectional view.

The organic photoelectric converting layer160may include an organic photoelectric converting material. The organic photoelectric converting layer160may be formed of a single layer as illustrated or may include a plurality of organic material layers. Particularly, the organic photoelectric converting layer160may include a p-type semiconductor compound and an n-type semiconductor compound to form a pn junction, may receive incident light and generate excitons, and may separate the generated excitons into holes and electrons.

The organic photoelectric converting layer160may photoelectrically convert light of a specific wavelength band (or a specific color). For example, the organic photoelectric converting layer160may photoelectrically convert light of a green color, and in this case, the organic photoelectric converting layer160may include a rhodamine-based pigment, a nerocyanine-based pigment, quinacridone, and/or the like. In addition, the organic photoelectric converting layer160may also photoelectrically convert light of a red color or a blue color, and/or infrared rays.

The difference in the etching speeds of the first insulating layer130aand the second insulating layer130bmay have the degree, in which the trench portion OP may have an appropriate size in plan view, and the first and second insulating layers130aand130bhave an appropriate undercut structure. Here, the appropriate undercut structure of the first and second insulating layers130aand130bmay have the degree, in which the first portion160a, the second portion160b, and the third portion160cof the organic photoelectric converting layer160may be separately formed from one another when the organic photoelectric converting layer160is deposited during a process for manufacturing the image sensor1.

An upper electrode170is positioned on the organic photoelectric converting layer160. The organic photoelectric converting layer160is positioned between the lower electrode151and the upper electrode170in each pixel PX. The upper electrode170may include a fourth portion170a, which is continuously formed on the pixel array unit AA and is disposed on the first portion160aof the organic photoelectric converting layer160, a fifth portion170b, which is disposed in the trench portion OP and is disposed on the second portion160bof the organic photoelectric converting layer160, and a sixth portion170c, which is disposed on the peripheral area PA at the external side of the trench portion OP and is disposed on the third portion160cof the organic photoelectric converting layer160.

In some embodiments, an edge of the sixth portion170bmay be aligned with an edge of the fifth portion170ain plan view, and an opposing edge of the sixth portion170bmay be aligned with an edge of the seventh portion170cin plan view. Most of the fifth portion170bmay be disposed between the fourth portion170aand the sixth portion170cin plan view, as illustrated inFIG. 2.

The fourth portion170aand the sixth portion170cmay be spaced apart from each other with the trench portion OP interposed therebetween. The fourth portion170aand the sixth portion170cmay further include a portion on a lateral surface the organic photoelectric converting layer160defining the trench portion OP, and a thickness (i.e., a thickness in the first direction X) of this portion may be smaller than a thickness (i.e., a thickness in the third direction Z) of a portion on the upper surface of the organic photoelectric converting layer160. Unlike the illustration, the upper electrode170may not be disposed on the lateral surface of the organic photoelectric converting layer160defining the trench portion OP.

The sixth portion170cincludes a lateral surface defining a part of the outer boundary surface EL. The upper electrode170may be removed and thus may not be present outside of the outer boundary surface EL on the peripheral area PA.

The lower electrode151and the upper electrode170may include, for example, a transparent conductive material, such as an Indium tin oxide (ITO) and an Indium zinc oxide (IZO).

The organic photoelectric converting layer160, the lower electrode151, and the upper electrode170in each pixel PX, collectively, form one organic photoelectric converter. The lower electrode151may be connected with the conductive plug121of the substrate120through the conductive connecting unit141extending through the insulating layer130in the thickness direction (i.e., the third direction Z). The conductive connecting unit141may include, for example, a metal material, such as tungsten (W), aluminum (Al), copper (Cu). The charges, which are photoelectrically converted and generated in the organic photoelectric converter, may be collected in the charge storing unit123through the conductive connecting unit141, the conductive plug121, the conductive connecting units116and117, and the conductive wire111.

In some embodiments, one pixel PX of the image sensor may include a plurality of the organic photoelectric converters, which overlaps one another. In this case, another lower electrode, another organic photoelectric converting layer, and another upper electrode, which may be formed of, respectively, the lower electrode151, the organic photoelectric converting layer160, and the upper electrode170, may be additionally deposited on the organic photoelectric converter to form another organic photoelectric converter. When one organic photoelectric converter positioned in one pixel PX photoelectrically converts light of a first wavelength band (or a first color) and reads a signal, another organic photoelectric converter of the same pixel PX may photoelectrically convert light of a second wavelength band (or a second color) different from the first wavelength band and read a signal. Further, when at least one organic photoelectric converter is positioned in one pixel PX and at least one photoelectric converter (e.g., inorganic photoelectric converter) is in the substrate120, the photoelectric converters may photoelectrically convert light of different wavelength bands and may read signals, respectively.

A passivation layer180is positioned on the upper electrode170. The passivation layer180may protect the organic photoelectric converter form an external material, and compensate for stress applied to the organic photoelectric converter.

The passivation layer180may be continuously formed on an entirety of the substrate120, including all of the pixel array unit AA, the peripheral area PA, and the trench portion OP. The passivation layer180may extend from the pixel array unit AA into the peripheral area PA. The passivation layer180in the trench portion OP may include a portion on a lateral surface of the upper electrode170, a portion on an exposed bottom surface of the first insulating layer130a, a portion on a lateral surface of the second insulating layer130bdefining the second opening132b, a portion on an exposed upper surface of the substrate120in the trench portion OP, a portion on the lateral surface of the second portion160bof the organic photoelectric converting layer160, and a lateral surface and an upper surface of the fifth portion170bof the upper electrode170, and the like.

A thickness of the passivation layer180may be substantially uniform.

The passivation layer180may include a lateral surface defining a part of the outer boundary surface EL. The passivation layer180may be removed and thus may not be present outside of the outer boundary surface EL on the peripheral area PA.

As illustrated inFIG. 2, the organic photoelectric converting layer160, the upper electrode170, and the passivation layer180may have the outer lateral surfaces aligned with the outer boundary surface EL, and the organic photoelectric converting layer160, the upper electrode170, and the passivation layer180may be removed and may not be present outside of the outer boundary surface EL in plan view.

The passivation layer180may include, for example, an insulating material, such as a silicon oxide (SiOx), a silicon nitride (SiNx), silicon oxynitride (SiON), an aluminum oxide (Al2O3), and may be formed of a single layer or multiple layers (for example, Al2O3/SiON).

The lateral surfaces of the first and second insulating layers130aand130bin the trench portion OP and the lateral surfaces of the portions160a,160b, and160cof the organic photoelectric converting layer160may be substantially perpendicular to the upper surface of the substrate120, but the inventive concepts are not limited thereto.

In some embodiments, a lens layer (not illustrated) including multiple micro-lenses, each of which corresponds to each pixel PX, may be disposed on the passivation layer180. Each micro-lens may collect incident light and may make the collected light be incident to the pixel PX. The lens layer may include, for example, a silicon oxynitride (SiON), and/or a resin-based material, such as styrene-based resin, acryl-based resin, styrene-acryl copolymer resin, and/or siloxane-based resin.

Still referring toFIG. 2, a circuit board100may be on a lower surface of the wiring layer110. The circuit board100may include, for example, a driving circuit inputting a driving signal for driving the plurality of pixels PX, a signal processing circuit processing each pixel signal from the pixel PX, a timing control circuit, and the like. The circuit board100may be connected to the substrate120and the wiring layer110by various methods, such as a wafer to wafer bonding method and a wire bonding method.

When light is incident on an upper side (i.e., the second surface BS side of the substrate120) of the image sensor1, the light of the wavelength band (or the color, for example, the green color) detected by the organic photoelectric converter may be photoelectrically converted in the organic photoelectric converting layer160of the organic photoelectric converter, the charges may be stored in the charge storing unit123and then may be read out, and the light of other wavelength bands (or the color, for example, the red color or the blue color) may be photoelectrically converted in the photoelectric converter PD within the substrate120and may be read out.

Then, examples of various structures of the portion A of the image sensor1illustrated inFIG. 2will be described with reference toFIGS. 3A, 3B, 3C, 3D, and 3E, together withFIGS. 1 and 2.

FIGS. 3A, 3B, 3C, 3D, and 3Eare cross-sectional views illustrating various structures of the portion A of the image sensor illustrated inFIG. 2.

Referring toFIG. 3A, the lateral surfaces of the portions160a,160b, and160cof the organic photoelectric converting layer160are not perpendicular to the upper surface of the substrate120, but are oblique to form tapered forms.

A thickness of a portion of the upper electrode170on the lateral surface of the organic photoelectric converting layer160may be smaller than that of a portion of the upper electrode170on the upper surface (i.e., a surface substantially parallel to the upper surface of the substrate120) of the organic photoelectric converting layer160. That is, a thickness of the upper electrode170may be different according to locations. In some embodiments, the thickness of the upper electrode170may gradually decrease as the upper electrode170becomes closer to an edge of the organic photoelectric converting layer160, as illustrated inFIG. 3A.

Next, referring toFIG. 3B, a structure around the trench portion OP may be substantially the same as that ofFIG. 3A, but at least parts of the lateral surfaces of the first and second insulating layers130aand130bdefining the first and second openings132aand132bof the trench portion OP may have curved surfaces, particularly, concave surfaces. Further, sizes of the first and second openings132aand132bmay vary according to a height of a portion of the first and second openings132aand132bfrom the substrate120. An area of the first opening132amay increase along the third direction Z, and an area of the second opening132bmay increase along the third direction Z. That is, the lateral surfaces of the first and second insulating layers130aand130bmay have the curved surfaces and the forms oblique to the upper surface of the substrate120.

Next, referring toFIG. 3C, a structure around the trench portion OP may be substantially the same as that ofFIG. 3B, but an area of the first opening132amay be largest adjacent a center of the first insulating layer130ain the third direction Z, and an area of the second opening132bmay be largest adjacent a center of the second insulating layer130bin the third direction Z.

Next, referring toFIG. 3D, the trench portion OP may be formed up to an inner side of the substrate120. A lower portion of the trench portion OP may be in the substrate120. That is, the upper surface of the substrate120corresponding to the trench portion OP may form a recess portion125, which is concave in a down direction and the second portion160bof the organic photoelectric converting layer160and the fifth portion170bof the upper electrode170may be positioned on the recess portion125.

Next,FIG. 3Eillustrates the example, in which the plurality of insulating layers130includes three layers. That is, the plurality of insulating layers130may include the first insulating layer130a, the second insulating layer130b, and a third insulating layer130c. As described above, the first insulating layer130aand the second insulating layer130bmay have different layer qualities (e.g. different properties), and the second insulating layer130band the third insulating layer130cmay also have different layer qualities (e.g. different properties). The first to third insulating layers130a,130b, and130cmay have different etching speeds. The first to third insulating layers130a,130b, and130cmay be etched at different rates by an etching process. In some embodiments, the insulating layer, which is farther from the substrate120, among the plurality of insulating layers130may have a lower etching speed.

The first insulating layer130a, the second insulating layer130b, and the third insulating layer130cinclude the first, second and third openings132a,132b, and132c, respectively, and the first, second and third openings132a,132b, and132c, collectively, form the trench portion OP. The first, second and third openings132a,132b, and132cmay overlap one another in plan view and may be connected in the vertical direction. A size of the first opening132a(i.e., an upper portion of the trench portion OP) of the first insulating layer130amay be smaller than a size of the second opening132bof the second insulating layer130b(i.e., a middle portion of the trench portion OP), and the size of the second opening132bof the second insulating layer130bmay be smaller than a size of the third opening132c(i.e., a lower portion of the trench portion OP) of the third insulating layer130c. Accordingly, the lateral surfaces of the first to third insulating layers130a,130b, and130cmay form the plurality of undercut structures in the trench portion OP.

According toFIG. 3E, the undercut structure of the insulating layer130in the trench portion OP may ensure separation of the first portion160a, the second portion160b, and the third portion160cof the organic photoelectric converting layer160when the organic photoelectric converting layer160is deposited.

Next, the image sensor1having a different structure according to example embodiments will be described with reference toFIGS. 4, 5A, and 5B.

FIG. 4is a cross-sectional view of the image sensor1according to example embodiments,FIG. 5Ais a plan view of an image sensor according to example embodiments, andFIG. 5Bis a cross-sectional view of the image sensor illustrated inFIG. 5Ataken along the line VA-VA′.

First, referring toFIG. 4, the image sensor1according to example embodiments may be substantially the same as the image sensors1discussed with reference toFIG. 2. The image sensor1ofFIG. 4may further include at least one of a first auxiliary layer161including portions161a,161b, and161cbetween an organic photoelectric converting layer160and the lower electrode151or the first insulating layer130a, and a second auxiliary layer162including portions162a,162b, and162cbetween the organic photoelectric converting layer160and the upper electrode170.

Each of the first auxiliary layer161and the second auxiliary layer162may include, for example, at least one selected from a hole injecting layer (HIL) for easily injecting holes, a hole transporting layer (HTL) for easily transporting holes, an electron blocking layer (EBL) for blocking a movement of electrons, an electron injecting layer (EIL) for easily injecting electrons, an electron transporting layer for easily transporting electrons (ETL), and a hole blocking layer (HBL) for blocking a movement of holes. For example, the first auxiliary layer161may be an electron blocking layer, and the second auxiliary layer162may be a hole blocking layer.

The first auxiliary layer161and the second auxiliary layer162may include, for example, an organic material, an inorganic material, and/or an organic-inorganic material.

In some embodiments, one of the first auxiliary layer161and the second auxiliary layer162may be omitted.

Next, referring toFIGS. 5A and 5B, an image sensor1aaccording to example embodiments may be substantially the same as the image sensor1illustrated inFIGS. 1 and 2, but may be different in a position of an outer boundary surface EL in plan view. The outer boundary surface EL may overlap a trench portion OP in plan view. That is, the outer lateral surfaces of the organic photoelectric converting layer160, the upper electrode170, and a passivation layer180aligned in the outer boundary surface EL may be in the trench portion OP.

Referring toFIG. 5B, a second portion160bof the organic photoelectric converting layer160, a fifth portion170bof the upper electrode170, and the passivation layer180include lateral surfaces defining the outer boundary surface EL that is in the trench portion OP. That is, the organic photoelectric converting layer160, the upper electrode170, and the passivation layer180may be removed and may not be present outside of the outer boundary surface EL disposed in the trench portion OP. Accordingly, a third portion160cof the organic photoelectric converting layer160and a sixth portion170cof the upper electrode170inFIG. 2may be omitted, and the lateral surface of the passivation layer180may be in the trench portion OP.

In some embodiments, a portion of the passivation layer180may be disposed on a lateral surface facing a left side of a second opening132bof a second insulating layer130bin the trench portion OP. However, as described above, the passivation layer180may not be outside of the outer boundary surface EL.

Now, a method of manufacturing an image sensor according to example embodiments will be described with reference toFIGS. 6 to 10together withFIGS. 1 and 2. Herein, an operation of forming a lens layer (e.g.,190inFIG. 11) which is not illustrated inFIG. 2will also be described.

FIGS. 6 to 10are cross-sectional views sequentially illustrating a manufacturing operation according to a method of manufacturing an image sensor according to example embodiments.

First, referring toFIG. 6, a plurality of photoelectric converters PD, a plurality of conductive plugs121, and a plurality of charge storing units123are formed in a substrate120. The operation may be performed on a first surface FS of the substrate120. Next, an insulating layer115is deposited on the first surface FS of the substrate120and then conductive connecting units116and117are formed, and a plurality of pixel transistors, one or more wires including a connection wire111, and a wiring layer110including one or more interlayer insulating layers are formed on the insulating layer115.

Next, a circuit board100may be bonded onto the wiring layer110(a lower surface of the wiring layer110inFIG. 6). However, the bonding operation of the circuit board100may also be performed later.

The substrate120may be reversed so that a second surface BS that is opposite the first surface FS heads a front side. One end of the conductive plug121may be exposed by removing a portion of the substrate120at the second surface BS side by a predetermined thickness by using a process, such as chemical mechanical polishing (CMP).

Next, the plurality of insulating layers130including a first insulating layer130aand a second insulating layer130bis sequentially deposited on the second surface BS of the substrate120exposing the conductive plug121. The first insulating layer130aand the second insulating layer130bmay be formed by sequentially depositing different insulating materials by using a chemical vapor deposition (CVD) process and the like, or may be formed to have different layer qualities (e.g., properties) by depositing the same insulating material under different deposition conditions.

For example, the second insulating layer130bmay be formed on the second surface BS of the substrate120by using a tetraethylorthosilicate (TEOS) CVD process and the like, and then the first insulating layer130, which is denser than the second insulating layer130b, may be formed by using a high density plasma (HDP) CVD process and the like. The first insulating layer130aand the second insulating layer130bformed as described above may include an insulating material, such as a silicon oxide (SiOx), a silicon nitride (SiNx), a hafnium oxide (HfOx), and an aluminum oxide (Al2O3).

Next, a plurality of openings is formed by patterning the first and second insulating layers130aand130bby using a photolithography process, and then conductive connecting units141, which extend through the insulating layer130in the third direction Z, is formed by depositing, patterning, and polishing a conductive (e.g., metal) material, such as tungsten (W), aluminum (Al), and copper (Cu).

Next, a plurality of lower electrodes151is formed by depositing a transparent conductive material, such as an ITO and an IZO, on the first insulating layer130a, and pattering the transparent conductive material by using a photolithography process and the like. Next, an insulating material (for example, the same material as that of the first insulating layer130a) may be deposited on the lower electrodes151and the first insulating layer130a, and then an upper surface of the first insulating layer130amay be polished by a CMP method and the like until upper surfaces of the lower electrodes151and an upper surface of the first insulating layer130amay form a flat surface together. In some embodiments, upper surfaces of the lower electrodes151and the first insulating layer130amay be coplanar.

Next, first and second preliminary openings131aand131bare formed by patterning the insulating layer130along the outer periphery of the pixel array unit AA by using a photolithography process and the like. A photoresist50patterned by the photolithography process may be formed on the insulating layer130, and the insulating layer130may be etched by using a first etching method. The first etching method may be an anisotropic etching method, such as a dry etching. According to the first etching method, as illustrated inFIG. 6, a lateral surface of the first preliminary opening131aof the first insulating layer130aand a lateral surface of the second preliminary opening131bof the second insulating layer130bmay be vertically aligned and may be substantially perpendicular to an upper surface of the substrate120to form one vertical surface.

Next, referring toFIG. 7, portions of the first and second insulating layers130aand130baround the first and second preliminary openings131aand131bare additionally etched by using a second etching method. The second etching method may have higher isotropy than that of the first etching method, and may be, for example, a wet etching method. During the second etching method, a wet etching speed of the second insulating layer130bis higher than a wet etching speed of the first insulating layer130a, so that the second insulating layer130bis more rapidly etched and thus an undercut structure is formed in the first insulating layer130aand the second insulating layer130bas illustrated inFIG. 7. Accordingly, an first opening132ahaving a first width WA in the first direction X is formed in the first insulating layer130aand an second opening132bhaving a second width WB in the first direction X is formed in the second insulating layer130bto form a trench portion OP. The second width WB may be greater than the first width WA. The second width WB may be, for example, about 0.5 μm to about 2 μm, but not limited thereto.

As illustrated inFIG. 7, when a virtual straight line VL, which is in contact with a lateral surface of the first insulating layer130a, is drawn from a bottom end of a lateral surface of the second insulating layer130b, an angle at between the virtual straight line VL and a line vertical to the upper surface of the substrate120may be, for example, about 20° or more, but not limited thereto. The degree of undercut in the first and second openings132aand132bof the first and second insulating layers130aand130bmay be appropriately adjusted to the degree, in which the portion of the organic photoelectric converting layer160positioned on the first insulating layer130ais separable from the portion of the organic photoelectric converting layer160positioned inside the second opening132bwhen the organic photoelectric converting layer160is deposited by a subsequent process.

Next, referring toFIG. 8, the organic photoelectric converting layer160is formed by depositing an organic photoelectric converting material on the entire surface of the substrate120by using a first depositing method. The first depositing method may be an anisotropy depositing method, such as a physical vapor deposition (PVD) process. According to the first depositing method, the organic photoelectric converting layer160is not formed on the lateral surface of the second opening132bof the second insulating layer130band the organic photoelectric converting layer160is formed so as to include separated first portion160a, second portion160b, and third portion160cby the undercut structures of the first and second openings132aand132bof the first and second insulating layers130aand130b. The first portion160aand the third portion160care positioned on the first insulating layer130awhile being spaced apart from each other, and the second portion160bis positioned in the trench portion OP. Accordingly, the first portion160aof the organic photoelectric converting layer160positioned in the pixel array unit AA may be physically separated from the second portion160band the third portion160cof the organic photoelectric converting layer160positioned in a peripheral area PA.

Next, an upper electrode170is formed by depositing a transparent conductive material, such as an ITO and an IZO, on the organic photoelectric converting layer160by using the anisotropy depositing method (the first depositing method), such as a PVD process. According to the first depositing method, the upper electrode170is not formed on the lateral surface of the second opening132bof the second insulating layer130band the upper electrode170is formed so as to include separated fourth portion170a, fifth portion170b, and sixth portion170cby the undercut structures of the first and second openings132aand132bof the first and second insulating layers130aand130b. The fourth portion170aand the sixth portion170care positioned on the organic photoelectric converting layer160while being spaced apart from each other, and the fifth portion170bis positioned in the trench portion OP.

Next, referring toFIG. 9, a passivation layer180is formed by depositing, for example, an insulating material, such as a silicon oxide (SiOx), a silicon nitride (SiNx), a silicon oxynitride (SiON), an aluminum oxide (Al2O3), on the entire surface of the substrate120by using a second depositing method. The second depositing method is a depositing method having higher isotropy than that of the first depositing method, and may be, for example, a chemical vapor deposition (CVD) process.

The passivation layer180may also be formed on the lateral surface of the second opening132bof the second insulating layer130b, so that the passivation layer180may be continuously formed with a substantially uniform thickness.

Next, referring toFIG. 10, a portion positioned at the external side of the pixel array unit AA (a portion positioned at an external side of an outer boundary surface EL) is removed by patterning the organic photoelectric converting layer160, the upper electrode170, and the passivation layer180. Portions of the organic photoelectric converting layer160, the upper electrode170, and the passivation layer180outside the outer boundary surface EL may be removed. The patterning method may use, for example, a photolithography process, and a etching process (e.g., a dry etching process using plasma), but is the patterning method is not limited thereto. According to the patterning method, the organic photoelectric converting layer160, the upper electrode170, and the passivation layer180are left only at an inside of the outer boundary surface EL, and the organic photoelectric converting layer160, the upper electrode170, and the passivation layer180include the lateral surfaces defining the outer boundary surface EL. The outer boundary surface EL may also be positioned in the peripheral area PA at the external side of the trench portion OP as illustrated inFIG. 10, and may also be positioned in an area overlapping the trench portion OP.

As appreciated by the inventors, the organic photoelectric converting layer160may be easily affected by oxygen, moisture, an etchant, and the like, so that when the organic photoelectric converting layer160is exposed to those, a characteristic of the organic photoelectric converter may be degraded. According to example embodiments of the present inventive concepts, the second portion160bor the third portion160cof the organic photoelectric converting layer160, which are exposed to the etchant and the like, is physically separated from the first portion160aon the pixel array unit AA, so that the first portion160aof the organic photoelectric converting layer160on the pixel array unit AA may not be exposed to oxygen, moisture, the etchant, and the like and may not affected. Therefore, properties of the organic photoelectric converter may not be changed or degraded. Further, the etching process is performed in the state where the passivation layer180completely covers the first portion160aof the organic photoelectric converting layer160on the pixel array unit AA, so that the organic photoelectric converting layer160on the pixel array unit AA may not be damaged.

Further, patterning the organic photoelectric converting layer160, the upper electrode170, and the passivation layer180may use a conventional photolithography process, so that additional process for protecting the organic photoelectric converting layer160may not be necessary. Therefore, additional costs and process time may not be required, and there may be no concern about the complexity of the manufacturing process. Further, it may be possible to etch and pattern the organic photoelectric converting layer160, the upper electrode170, and the passivation layer180at one time, so that the manufacturing process may be simplified and the manufacturing time may decrease.

Subsequently, a material of the lens, such as a resin-based material, may be deposited on the entire surface of the substrate120by using, for example, a spin coating method and the like, a photoresist (not illustrated) shaped like a micro-lens may be formed on the material, and then a lens layer190including micro-lenses ML positioned on corresponding pixels PX may be formed by, for example, an etch back process.

Next, an image sensor according to example embodiments will be described with reference toFIG. 11together with the aforementioned drawings.

FIG. 11is a cross-sectional view of an image sensor according to example embodiments.

Referring toFIG. 11, an image sensor1according to example embodiments may be substantially the same as the image sensor illustrated inFIGS. 2 and 10, but each pixel PX may include a plurality of photoelectric converters PD1and PD2in a substrate120.FIG. 11illustrates an example, in which each pixel PX includes two photoelectric converters PD1and PD2. The photoelectric converters PD1and PD2may receive light of different wavelength bands (or different colors) and photoelectrically convert the light. For example, the photoelectric converter PD1may receive blue light and photoelectrically convert the received blue light, and the photoelectric converter PD2may receive red light and photoelectrically convert the received red light.

The plurality of photoelectric converters PD1and PD2in each pixel PX may be overlap each other in a vertical direction as illustrated inFIG. 11. In some embodiments, the plurality of photoelectric converters PD1and PD2may not overlap and may be positioned in different areas in plan view.

Next, an image sensor according to example embodiments will be described with reference toFIGS. 12 and 13together with the aforementioned drawings.

FIG. 12is a plan view of an image sensor according to example embodiments, andFIG. 13is a cross-sectional view of the image sensor illustrated inFIG. 12taken along the line XIII-XIII′.

Referring toFIG. 12, an image sensor1baccording to example embodiments may be substantially the same as the image sensor1illustrated inFIGS. 1 and 2, but the image sensor1bmay further include a driving circuit, such as a first driver400, a second driver500, and a controller600positioned in the peripheral area PA.

The first driver400may be connected with a plurality of first signal lines10and transmit a driving signal for driving a pixel PX to the first signal lines10.

The second driver500, which is a signal processing circuit, may be connected with a plurality of second signal lines20, and may receive and process a pixel signal according to charges, which are generated according to the amount of light received by a photoelectric converter of each pixel PX, and generate image data.

The controller600may provide a timing signal and a control signal to the first driver400and the second driver500and control the operations of the first driver400and the second driver500.

Referring toFIG. 13, a structure of a cross-section of the image sensor1bmay be substantially the same as that discussed above, so that differences will be mainly described.

The image sensor1bmay include a substrate120A (e.g., a semiconductor substrate), and the substrate120A may include a plurality of photoelectric converters PD and a plurality of charge storing units123A.

A wiring layer110A may be positioned on a first surface FS of the substrate120A. The wiring layer110A may include a plurality of pixel transistors for reading charges generated in the photoelectric converter PD as a pixel signal or a plurality of conductive layers for forming several wires, and one or more interlayer insulating layers, and may include a driving circuit, such as a first driver400, a second driver500, and a controller600, which are described above.

The wiring layer110A may include a plurality of conductive layers113, which is vertically and sequentially connected in each pixel PX and extends through the wiring layer110A, and one or more conductive connecting units114. The conductive layers113and the conductive connection units114may be alternately disposed in each pixel PX, and may transmit the charges photoelectrically converted in an organic photoelectric converter to the charge storing unit123A of the substrate120A.

A plurality of insulating layers130, a plurality of lower electrodes151, an organic photoelectric converting layer160, an upper electrode170, and a passivation layer180may be sequentially positioned on the wiring layer110A. It will be understood that the wiring layer110A can be considered as an underlying layer under the plurality of insulating layers130, and the first and second openings132aand132bmay expose a portion of the wiring layer110A.

The image sensors according to example embodiments may be applied to various electronic devices, such as a mobile phone, a digital camera, a camcorder, a robot, and a biosensor.