JP2019186544A - Image sensor and method of manufacturing image sensor - Google Patents

Abstract

To provide an image sensor and a method of manufacturing the image sensor.SOLUTION: An image sensor 100 includes a block layer including an absorption layer and a transparent layer, a lens element 110 located in a bottom portion of the block layer, and a sensing element 140 located to face the lens element 110.SELECTED DRAWING: Figure 1

Description

  Hereinafter, techniques relating to an image sensor and a manufacturing method thereof are provided.

  The image sensor can convert an optical signal including video information of an object into an electrical signal as an apparatus for capturing an image of the object. Image sensors are included in various electronic devices. For example, CCD (Charge Coupled Device) image sensors and CMOS (Complementary Metal Oxide Semiconductor) image sensors are widely used.

  The CMOS image sensor includes a plurality of pixels including a photoelectric conversion element and a plurality of transistors. A signal photoelectrically converted by the photoelectric conversion element is processed and output by a plurality of transistors, and image data is generated based on the pixel signal output from the pixel. Each pixel can photoelectrically convert light of a specific color or a specific wavelength range and output a signal thereby.

  An object of an image sensor according to an embodiment is to prevent optical crosstalk and adjust the viewing angle during manufacturing.

  An image sensor according to an embodiment includes an absorption layer and a transparent layer, and detects light from a block layer that allows light received from the outside to pass through an opening formed in the absorption layer and the transparent layer. And a lens element that transmits to the element.

  The detection element may be spaced apart from the lens element and receive light that has passed through the opening and the lens element.

  The lens element may refract the light to form a focal point on the detection element.

  The block layer may be separated from the detection element by a focal length of the lens element.

  The image sensor may further include a transparent substrate that allows light to pass through.

  The opening may be formed to be aligned with the arrangement of the lens elements at the block layer.

  The image sensor may further include a spacer that maintains a distance between the block layer and the detection element.

  The absorption layer and the transparent layer may be alternately arranged in the block layer.

  The absorption layer may include a stop formed in a circular area centered on a point corresponding to the lens element.

  The absorbing layer includes a first diameter stop formed around a point corresponding to the lens element, and the block layer has a different absorbing layer formed with a second diameter stop different from the first diameter. May further be included.

  In the block layer, the diameter of the opening may gradually change from one surface of the block layer to another surface.

  The transparent layer can transmit light in a predetermined wavelength band.

  The block layer may have a height that is determined based on a predetermined viewing angle.

  The block layer may include a number of absorption layers determined based on a predetermined field of view (FOV).

  The diameter of the opening may be based on a predetermined amount of light, and the block layer may be separated from the detection element by a focal length determined based on the predetermined amount of light.

  The transparent layer may include a transparent polymer that transmits light.

  The absorption layer may include a black matrix material that absorbs light.

  The block layer includes a plurality of absorption layers, and a circular diaphragm formed in each of the plurality of absorption layers includes a transparent substrate disposed on the block layer, a refractive index of the transparent layer, and a predetermined viewing angle. And having a diameter determined based on

  The lens element and the detection element are arranged in a planar array pattern,

  The absorbing layer may include a stop formed in alignment with the planar array pattern.

  The transparent substrate may be disposed on a first side of the block layer, and the lens element may be disposed on a second side of the block layer opposite to the first side.

  An image sensor manufacturing method according to an embodiment includes a step of providing a transparent substrate, a step of providing a block layer including an absorption layer and a transparent layer, and a lens according to a pattern in which an opening is formed in the block layer. Providing an element.

  An image sensor manufacturing method according to another embodiment provides a step of disposing a block layer including a transparent layer and an absorption layer on a transparent substrate, and a lens element corresponding to a pattern of openings formed in the block layer. Including the step of.

  The step of disposing the block layer comprises: coating the transparent substrate with an opaque polymer; disposing a mask comprising the pattern on a plurality of portions of the opaque polymer; and exposing the block layer according to the pattern of the mask. Irradiating the opaque polymer with ultraviolet light, removing the portions of the opaque polymer covered by the mask, and applying a negative photoresist between and on the remaining opaque polymer. Coating a transparent layer comprising and exposing the transparent layer to ultraviolet light.

  The method may further include a step of strengthening a bond between the remaining opaque polymer and the transparent layer by performing a hydrophilic treatment.

  The mask may include a circular mask made of a lattice pattern.

  The absorption layer may include a negative photoresist.

  Providing the lens element comprises: coating a thermoplastic polymer layer including a positive photoresist on the block layer; and disposing a mask comprising the pattern on a plurality of portions of the thermoplastic polymer layer. Exposing the thermoplastic polymer layer to ultraviolet light in accordance with the pattern of the mask; and patterning the thermoplastic polymer layer by dissolving the thermoplastic polymer layer exposed to ultraviolet light with a developer. And applying a hydrophobic coating to the patterned thermoplastic polymer layer and heating the hydrophobic coated thermoplastic polymer layer to form a spherical lens.

  The thermoplastic polymer layer may include a transparent material that can be deformed by heat.

  An image sensor according to an embodiment includes a block layer including an absorption layer and a transparent layer that are alternately stacked together, an opening formed in the transparent layer and the absorption layer to transmit light to a lens element, A detection element spaced from the lens element and configured to receive light from the lens element.

  The diameter of the opening may gradually change between both sides of the block layer.

  The opening includes a circular stop in each of the absorption layers, and the diameter of the circular stop is based on a viewing angle and a refractive index of the transparent substrate and the transparent layer disposed on the block layer.

  The spacer further includes a spacer positioned at an outer boundary between the detection element and the block layer, and the spacer is configured to maintain a substantially same distance as a focal length of the lens element between the block layer and the detection element. Can be done.

  An image sensor according to an embodiment can reduce optical crosstalk through a block layer including an absorption layer and a transparent layer, can adjust a viewing angle during manufacturing, and can be made thinner.

It is a figure which shows the structure of the image sensor which concerns on one Embodiment. It is a figure which shows the block layer and lens element which concern on one Embodiment. It is a figure which shows the cross section of the block layer and lens element which concern on one Embodiment. It is a figure explaining the viewing angle which the image sensor concerning one embodiment has. It is a figure explaining the viewing angle determined by the opening part of the block layer which concerns on one Embodiment. It is a figure explaining the viewing angle determined by the opening part of the block layer which concerns on other one Embodiment. It is a flowchart explaining the manufacturing method of the image sensor which concerns on one Embodiment. It is a figure explaining the provision method of the block layer which concerns on one Embodiment. It is a figure explaining the provision method of the lens element which concerns on one Embodiment. 3 shows an image of a structure in which lens elements according to an embodiment are integrated on one surface of a block layer, taken by a scanning electron microscope. 3 shows an image of a structure in which lens elements according to an embodiment are integrated on one surface of a block layer, taken by an optical microscope. It is a figure which shows the light transmittance by the number of the absorption layers contained in the block layer which concerns on one Embodiment. 1 illustrates an image taken by a confocal laser scanning microscope of an upper surface and side surfaces of an image sensor according to an embodiment. It is a figure which shows the intensity | strength profile (intensity profile) of the image sensor which concerns on one Embodiment. 3 shows an image taken through an image sensor according to an embodiment. The result by which the viewing angle of the image sensor concerning one embodiment was measured is shown. It is a figure explaining the influence which the block layer which concerns on one Embodiment has on MTF (modulation transfer function). It is a figure explaining the influence which the block layer concerning one Embodiment exerts on MTF.

  Various modifications can be made to the embodiments described below. The scope of the patent application is not limited or limited by such embodiments. The same reference numerals provided in each drawing denote the same members.

  The specific structural or functional descriptions disclosed herein are merely exemplary for the purpose of illustrating the embodiments, which may be implemented in a variety of different forms and are described herein. It is not limited to the described embodiments.

  The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. An expression used in the singular encompasses the expression of the plural, unless it has a clearly different meaning in the context. In this specification, terms such as “including” or “having” indicate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification. It should be understood as not excluding the possibility of the presence or addition of one or more other features or numbers, steps, actions, components, parts, or combinations thereof.

  Unless defined differently, all terms used herein, including technical or scientific terms, are the same as commonly understood by one of ordinary skill in the art to which this embodiment belongs. Has meaning. Commonly used predefined terms should be construed as having a meaning consistent with the meaning possessed in the context of the related art and are ideal or excessive unless explicitly defined herein. It is not interpreted as a formal meaning.

  Further, in the description with reference to the accompanying drawings, the same constituent elements are given the same reference numerals regardless of the reference numerals, and the overlapping description thereof is omitted. In the description of the embodiment, when it is determined that a specific description of a related known technique unnecessarily obscure the gist of the embodiment, a detailed description thereof will be omitted.

  FIG. 1 is a diagram illustrating a configuration of an image sensor according to an embodiment.

  The image sensor 100 represents an apparatus for capturing an image of a subject. According to one embodiment, the image sensor 100 includes a lens element 110, a block layer 120, a transparent substrate 130, a detection element 140, a spacer 150, and a camera chip 190.

  The lens element 110 is an element that refracts light received from the outside and collects light. The lens element 110 refracts light to form a focal point on the detection element 140. For example, one surface of the lens element 110 has a protruding portion, and the other surface has a flat surface. For example, the lens element 110 may be a microlens having a full surface, but is not limited thereto. One surface having a protruding portion of the lens element 110 is formed into a spherical shape, an aspherical shape, a concave lens, a Fresnel shape, or the like. However, the present invention is not limited to this, and the lens element 110 may be embodied as a concave lens.

  A set of lens elements 110 is denoted as a lens array. For example, the lens array includes a plurality of lens elements arranged along a planar array pattern (eg, a lattice pattern).

  The block layer 120 indicates a layer that blocks light. The block layer 120 includes an absorption layer in which a transparent layer and a pattern (for example, a hole pattern) are formed. The block layer 120 includes an opening formed by the pattern of the absorption layer. The block layer 120 can transmit light received from the outside to the lens element 110 only through the opening. The absorption layer and the transparent layer included in the block layer 120 will be described in detail with reference to FIGS. 2 and 3 below.

  The transparent substrate 130 indicates a transparent substrate that can transmit light. The transparent substrate 130 is disposed on the block layer 120. However, the arrangement of the transparent substrate 130 is not limited to this, and the transparent substrate 130 may be arranged on the lens element 110 arranged on the block layer 120. For example, the transparent substrate 130 includes a glass wafer, but the type of the transparent substrate 130 is not limited to this.

  The detection element 140 is separated from the lens element 110 and receives light that has passed through the opening of the block layer 120 and the lens element 110. The detection element 140 receives the light collected by the lens element 110 from the light that has passed through the openings of the transparent substrate 130 and the block layer 120. The detection element 140 outputs a signal indicating the intensity of the received light. For example, the detection element 140 detects light corresponding to an arbitrary color channel and outputs a signal indicating the intensity of the corresponding color. The color channel includes, for example, a red channel, a green channel, and a blue channel as channels indicating colors corresponding to a part of the visible region. Each detection element 140 detects light corresponding to one color channel of the red channel, the green channel, and the blue channel. However, the wavelength that can be detected by the detection element 140 is not limited to this, and the detection element 140 can also detect infrared rays or ultraviolet rays depending on the design.

  The set of detection elements 140 is referred to as a sensor array. For example, the sensor array includes a plurality of detection elements arranged along a planar array pattern (eg, a lattice pattern). The sensor array may include a detection element 140 that detects red, a detection element 140 that detects green, and a detection element 140 that detects blue. The sensor array is detected by distinguishing three colors.

  The spacer 150 maintains a distance between the block layer 120 and the detection element 140. For example, the spacer 150 supports the block layer 120 and the detection element 140. In FIG. 1, the spacer 150 is shown as being disposed along the outer boundary of the sensor array, and the spacer 150 supports the outer boundary of the block layer 120.

  The camera chip 190 is a chip on which a sensor array is implemented. The camera chip 190 may be embodied at a wafer level, for example.

  According to one embodiment, the lens element 110, the block layer 120, the transparent substrate 130, the detection element 140, the spacer 150, and the camera chip 190 are combined through an integration process.

  FIG. 2 is a diagram illustrating a block layer and a lens element according to an embodiment.

  The block layer 220 includes an absorption layer 221 and a transparent layer 222. The block layer 220 allows light received from the outside to pass through the opening 229 formed in the absorption layer 221 and the transparent layer 222. For example, the block layer 220 provides the lens element 210 with light received from the outside through the opening 229.

  The absorption layer 221 may be shown as a light absorption layer, for example, as a layer that absorbs light. The absorption layer 221 includes a black matrix material that absorbs light. The black matrix material includes, for example, Black SU-8. However, the material of the absorption layer 221 is not limited to this, and the absorption layer 221 may include a negative photoresist that absorbs light. The absorption layer 221 includes a stop formed in a circular region centered on a point corresponding to the lens element 210 in the absorption layer 221 according to the arrangement of the lens element 210. The absorption layer 221 includes a stop formed in alignment with the planar array pattern.

  The transparent layer 222 indicates a layer that transmits light. The transparent layer 222 includes a transparent polymer that transmits light. The transparent polymer may include, for example, SU-8. However, the material of the transparent layer 222 is not limited to this, and the transparent layer 222 may include a negative photoresist that transmits light. As a further example, the transparent layer 222 may transmit light in a predetermined wavelength band. For example, the transparent layer 222 may transmit only light in the visible light band.

  The block layer 220 forms the opening 229 with a structure in which the absorption layer 221 and the transparent layer 222 are alternately arranged. The layer corresponding to the opposite surface of the block layer 220 on which the lens element 210 is disposed is the absorption layer 221. However, the arrangement of the absorption layer 221 is not limited to this, and the absorption layer 221 may be arranged on the same surface as the surface on which the lens element 210 is arranged.

  A circular diaphragm is formed in the absorption layer 221 along the lattice pattern. For example, when the block layer 220 includes a plurality of absorption layers, the apertures of the plurality of absorption layers form the openings 229. The opening 229 indicates a portion through which light passes through the block layer 220. The opening 229 is formed to align with the arrangement of the lens element 210 in the block layer 220. The opening 229 will be described with reference to FIG.

  The lens element 210 transmits light received from the outside to the detection element. For example, the lens element 210 is disposed below the block layer 220 and allows light provided from the opening 229 to pass therethrough. The lens element 210 has a protruding portion on one surface of the lens element 210, and the protruding portion is arranged to face the detection element. For example, the lens element 210 transmits light provided from the opening 229 to the detection element corresponding to the corresponding opening 229. However, the above-described structure is merely an example, and the present invention is not limited to this. For example, the lens element 210 is not limited to be disposed below the block layer 220, and the lens element 210 may be disposed above the block layer 220 or may be disposed both above and below the block layer 220. Further, instead of the protruding portion of the lens element 210 facing the detection element, the flat portion may be arranged to face the detection element. The lens element 210 may have a recessed portion instead of a portion protruding on one surface.

  The pattern (for example, hole pattern) formed on the block layer 220 according to an embodiment transmits light that has passed through an arbitrary opening 229 in the block layer 220 to a detection element corresponding to the corresponding opening 229, and Is prevented from going to other detection elements. Therefore, the block layer 220 having the hole pattern described above can reduce optical crosstalk. Further, the wide viewing angle of the image sensor can be designed according to the diameter of the hole pattern, the height of the block layer 220, and the like.

  FIG. 3 is a diagram illustrating a cross section of a block layer and a lens element according to an embodiment.

  The image sensor according to an embodiment includes a block layer 320 in which an opening 329 is formed and a lens element 310 disposed under the block layer 320. As shown in FIG. 3, the block layer 320 has a structure in which an absorption layer 321 and a transparent layer 322 are alternately stacked. Each absorbing layer 321 may include a circular aperture, which may be filled with the same material as the transparent layer 322.

  The region where the diaphragm is formed in the absorption layer 321 transmits light, and the remaining region where the diaphragm is not formed absorbs light. The light that has passed through the diaphragm of the arbitrary absorption layer 321 passes through the next transparent layer 322. The light that has passed through the next transparent layer 322 passes through the stop of the next absorption layer. Therefore, the apertures of each of the plurality of absorption layers form a cylindrical opening 329 that allows light received from the outside to pass therethrough.

  The light that has passed through the opening 329 is provided to the lens element 310. The lens element 310 can collect the light that has passed through the opening 329 and transmit it to the detection element.

  FIG. 4 is a diagram illustrating the viewing angle of the image sensor according to the embodiment.

The block layer 420 has a height H determined based on a predetermined viewing angle. For example, the viewing angle of the image sensor indicates the maximum incident angle θ ₁ with respect to the transparent substrate 430 at which light received from the outside can reach the detection element. The light incident on the transparent substrate 430 is refracted according to the refractive indexes of the transparent substrate 430 and the transparent layer 422. For example, in FIG. 4, it is assumed that light is incident on the transparent substrate 430 at an angle θ ₁ . The absorption layer 421 at block layer 420 absorbs light, the light by opening up the angle theta ₂ which can pass through the block layer 420 is determined. For example, the maximum angle θ ₂ at which light received from the outside can pass through the block layer 420 is determined according to the diameter of the opening formed in the block layer 420 and the height of the opening. The height of the opening corresponds to the height H of the block layer 420.

For example, in the image sensor, the relationship between the height H, θ ₂ , and θ ₁ of the block layer 420 can be shown as in Table 1 below.

  For example, according to Table 1, when the height H of the block layer 420 is 110 μm, the viewing angle of the image sensor is about 70 °.

  However, the configuration of the block layer 420 is not limited as described above. The block layer 420 includes a number of absorption layers 421 determined based on a predetermined viewing angle. For example, the height of the block layer 420 is determined based on a predetermined viewing angle, and the number of absorption layers 421 to be stacked is determined by the height of the block layer 420 and the interval between the absorption layers 421. The interval between the absorption layers 421 corresponds to the thickness of the transparent layer 422.

  FIG. 5 is a diagram illustrating the viewing angle determined by the opening of the block layer according to an embodiment.

  The absorption layer 521 includes a stop having a first diameter D1 formed around a point corresponding to the lens element 510. The block layer 520 further includes a different absorbing layer 522 formed with a diaphragm having a second diameter D2 different from the first diameter D1. The further absorbent layer 523 includes a stop with a third diameter D3 different from the second diameter D2. The first diameter D1, the second diameter D2, and the third diameter D3 have values that gradually increase or decrease. For example, the block layer 520 has a structure in which the diameter of the opening 529 gradually changes from one surface of the block layer 520 to the other surface. The number of absorption layers in the block layer 520 is not limited to that described.

FIG. 4 illustrates that the diameter of the opening 529 is constant, but FIG. 5 illustrates an example in which the diameter of the opening 529 increases. In FIG. 5, the diameter of the diaphragm formed in each absorption layer gradually increases from the absorption layer close to the lens element 510 to the absorption layer far from the lens element 510. As the diameter of the opening 529 gradually increases, the maximum angle θ _{2 at} which light can pass through the block layer 520 is increased by the opening 529. Here, the degree to which the diameter of the opening 529 increases is determined based on the refractive indexes of the transparent substrate 530 and the transparent layer and a desired viewing angle θ ₁ (hereinafter, a predetermined viewing angle). After the light incident on the transparent substrate 530 is refracted at a predetermined viewing angle θ ₁ , the degree to which the diameter of the opening 529 increases is determined according to the angle at which the corresponding light enters the block layer 520. . The degree to which the diameter of the opening 529 increases corresponds to the maximum angle θ ₂ that can pass through the block layer 520. Accordingly, the circular diaphragm formed in each of the plurality of absorption layers included in the block layer 520 has a diameter determined based on the refractive indexes of the transparent substrate 530 and the transparent layer and a predetermined viewing angle θ _1. Have.

  Further, the block layer 520 is separated from the detection element 540 by the focal length of the lens element 510. For example, the block layer 520 is disposed on the opposite side of the detection element 540 with respect to the lens element 510 as shown in FIG. However, the arrangement of the block layer 520 is not limited to this, and the block layer 520 can be arranged on the same side as the detection element 540 with the lens element 510 as a reference.

  For example, the block layer 520 has an opening diameter determined based on a predetermined amount of light, and is separated from the detection element 540 by a focal length determined based on the predetermined amount of light.

  FIG. 5 illustrates that the diameter of the opening 529 gradually increases, but FIG. 6 below illustrates an opposite example.

  FIG. 6 is a diagram illustrating the viewing angle determined by the opening of the block layer according to another embodiment.

  The block layer 620 is based on the lens element 610, and includes a first absorption layer 621 including a stop having a first diameter D1, a second absorption layer 622 including a stop having a second diameter D2, and a third including a stop having a third diameter. An absorption layer 623 is included. The first diameter D1, the second diameter D2, and the third diameter D3 gradually decrease. For example, the block layer 620 has a structure in which the diameter of the opening 629 gradually decreases from one surface of the block layer 620 to the other surface. Due to the structure in which the diameter of the opening 629 gradually decreases, the image sensor can observe a distant object more fully.

  FIG. 7 is a flowchart illustrating a method for manufacturing an image sensor according to an embodiment.

  According to one embodiment, the image sensor is stacked in the order of a transparent substrate, a block layer, a lens element, and a detection element.

  First, in step S710, a transparent substrate is provided. As described above, the transparent substrate may be a glass wafer, but is not limited thereto.

  In step S720, a block layer including an absorption layer and a transparent layer is provided. For example, the block layer is provided on a transparent substrate. As described above, the absorption layer and the transparent layer are alternately laminated, and the formation of such a block layer will be described with reference to FIG.

  Next, in step S730, a lens element is provided according to a pattern in which an opening is formed in the block layer. For example, the lens element is provided on the block layer. Hereinafter, a method of providing a microlens array as a lens element will be described with reference to FIG.

  FIG. 8 is a diagram for explaining a block layer providing method according to an embodiment.

  First, in step S821, an absorption layer is provided on a transparent substrate. For example, a black polymer (for example, Black SU-8) is coated as an absorption layer.

  In step S822, a mask is disposed on the absorption layer. The mask is arranged in a planar array pattern on the absorbing layer. For example, a circular mask is arranged along the lattice pattern. Ultraviolet rays are irradiated through a mask disposed on the absorption layer. The portion of the absorption layer excluding the mask is exposed to ultraviolet rays. The absorption layer may be composed of a negative photoresist. Photoresist represents a photosensitive material used in various processes and forms a patterned coating on the surface.

  Next, in step S823, the absorption layer patterned by ultraviolet exposure is developed with a developer. A solvent called a developer is applied to the surface. The portion of the negative photoresist exposed to ultraviolet light is insoluble in the developer. The portion not exposed by the negative photoresist is dissolved by the photoresist developer. Therefore, as shown in FIG. 8, the portion corresponding to the mask form in the absorption layer is dissolved and removed.

  In step S824, a transparent layer is coated on the absorption layer on which the pattern is formed. The block layer is exposed to ultraviolet light on the transparent layer coated on the patterned absorption layer. The transparent layer may also be composed of a negative photoresist, and the portion exposed to ultraviolet light is insoluble in the developer. Due to the exposure to UV light without a mask, the entire coated transparent layer can be fixed.

  Next, in step S825, a hydrophilic process is applied to the transparent layer. By the hydrophilic treatment, the bonding strength between the transparent layer and the absorbing layer is increased. The hydrophilic treatment can be, for example, an oxygen plasma treatment.

  In step S826, a plurality of layers (for example, N layers) are stacked by repeating steps S821 to S825 described above. Here, N is an integer of 2 or more. Absorbing layers and transparent layers are alternately laminated. While steps S821 to S825 described above are repeated, alignment is maintained between the patterns formed on each of the absorption layers. Therefore, a set of stops formed in each absorption layer corresponds to the opening.

  FIG. 9 is a diagram for explaining a lens element providing method according to an embodiment.

  First, in step S931, a thermoplastic polymer is provided on the block layer. The thermoplastic polymer indicates a material that can be deformed by heat as a transparent material for manufacturing a lens. For example, the thermoplastic polymer may exhibit AZ9260.

  Then, in step S932, a mask having a pattern aligned with the planar array pattern formed on the absorbing layer is disposed on the thermoplastic polymer. With the mask placed on the thermoplastic polymer, the thermoplastic polymer is exposed to ultraviolet light.

  Next, in step S933, the thermoplastic polymer patterned by ultraviolet exposure is developed with a developer. The thermoplastic polymer may be a positive photoresist, and a portion exposed by the positive photoresist is dissolved by a photoresist developer. The portion not exposed by the positive photoresist is insoluble in the phenomenon solution. Accordingly, as shown in FIG. 9, the portion of the coated thermoplastic polymer corresponding to the mask form is retained after UV exposure. If the mask is a circular mask, the thermoplastic polymer is held in a cylindrical form along the planar array pattern.

  Then, in step S934, a hydrophobic coating 901 (eg, Fluorocarbon nanofilm coating) is applied over the structure patterned with the thermoplastic polymer. The hydrophobic coating 901 increases the cohesive strength of the thermoplastic polymer.

  Next, in step S935, the shape of the microlens array is manufactured through a thermal reflow process. Since the cohesive force of the thermoplastic polymer is increased by the hydrophobic coating 901 applied in step S934 described above, the thermoplastic polymer is aggregated spherically.

  However, manufacture of the image sensor which concerns on one Embodiment is not limited to FIG. 7-9 mentioned above, It can change according to a design. Moreover, the order of each step of the manufacturing process described with reference to FIGS. 7 to 9 is not limited to that described above, and some processes may be omitted or added.

  FIG. 10 shows an image of a structure in which lens elements according to an embodiment are integrated on one surface of a block layer, taken by a scanning electron microscope. FIG. 10 shows a lens element taken by a scanning electron microscope. As shown in FIG. 10, the lens element is formed in a spherical shape along the lattice pattern below the block layer.

  FIG. 11 shows an image of a structure in which lens elements according to an embodiment are integrated on one surface of a block layer, taken by an optical microscope. FIG. 11 shows a lens element photographed by an optical microscope. As shown in FIG. 11, the focal points of the lens elements are uniformly formed and are indicated by white dots.

  FIG. 12 is a diagram illustrating the light transmittance according to the number of absorption layers included in the block layer according to the embodiment. FIG. 12 shows a result that the transmittance of light passing through the block layer decreases as the number of absorption layers included in the block layer increases. For example, when a 4.5 μm absorption layer is coated, about 40 to 50% of light is transmitted in one layer. Approximately 10% of the light is transmitted through the two layers. The four layers hardly transmit light in the visible light region.

  FIG. 13 shows an image obtained by photographing a top surface and a side surface of an image sensor according to an embodiment with a confocal laser scanning microscope. FIG. 13 shows images taken for a structure 1310 without a lens array, a structure 1320 without a block layer, and a structure 1330 having a lens array and a block layer, respectively.

  A structure 1310 without a lens array photographed by a confocal laser scanning microscope shows a shape in which the light path is not focused. A structure 1320 without a block layer photographed by a confocal laser scanning microscope shows a shape in which light is not blocked.

  The image sensor according to the embodiment has a structure 1330 having a lens array and a block layer, and has a shape in which light is blocked in the remaining portion except the opening while the light path is focused.

  FIG. 14 is a diagram illustrating an intensity profile of an image sensor according to an embodiment. FIG. 14 shows the result of comparing the intensity profiles for each structure shown in FIG. The image sensor according to one embodiment can effectively block light by about 60% compared to a structure without a block layer. Also in the focal plane, the image sensor according to the embodiment shows a uniform amount of light. A uniform amount of light indicates that the lens is manufactured uniformly.

  FIG. 15 shows an image taken through an image sensor according to an embodiment.

  The result of the image sensor shooting the original image on the upper row is shown as the lower image. The image sensor according to an embodiment can acquire a plurality of clear divided images while preventing crosstalk through the block layer.

  FIG. 16 shows a result of measuring the viewing angle of the image sensor according to the embodiment.

  When the image sensor according to an embodiment captures a target object image, the viewing angle of the image sensor is calculated from the distance observed as if the object is filled with the image captured by the image sensor and the length of the target object image. Is measured. The viewing angle of the image sensor shown in FIG. 16 is about 70 °.

  FIGS. 17 and 18 are diagrams for explaining the influence of a block layer according to an embodiment on an MTF (Modulation Transfer Function).

  FIG. 17 shows an MTF measurement image for structure 1710 without a block layer and an MTF measurement image for structure 1720 with a block layer. The MTF measurement image for the structure 1710 without the block layer has a low sharpness quality, whereas the structure 1720 with the block layer shows a high sharpness. As shown in FIG. 18, MTF can be measured for an image sensor having a block layer structure.

  An image sensor according to an embodiment is mounted on an ultra-thin camera application product such as a mobile digital camera. The image sensor is applied to ultra-small optical image equipment such as an endoscope camera and a drone.

  In an image sensor according to an embodiment, an absorption layer for preventing optical crosstalk is disposed on the opposite side of the detection element with respect to the lens element, and a vacant space between the lens element and the detection element is formed by a spacer. Retained. Accordingly, the image sensor according to the embodiment is thinly implemented.

  An image sensor according to an embodiment reduces optical crosstalk through a block layer including an absorption layer and a transparent layer, and the viewing angle is adjusted during manufacturing.

  A lens element may be disposed on the lower surface of the block layer in the image sensor according to an embodiment. Since the block layer is disposed on the upper surface of the lens element, optical crosstalk can be reduced. Further, a transparent substrate is arranged on the upper surface of the block layer by the image sensor. Since the transparent substrate is disposed on the upper surface of the block layer, the received light may be refracted and the viewing angle may be efficiently expanded. The viewing angle of the image sensor can be adjusted according to the thickness of the transparent layer and the number of absorption layers stacked. In addition, the viewing angle of the image sensor is determined by designing the absorption layers with different widths or diameters of the diaphragms formed in the individual absorption layers and having different widths or diameters.

  An image sensor according to an embodiment is integrated in a semiconductor and used in an ultra thin camera. Further, the amount of light received by the image sensor can be adjusted according to the size of the diaphragm formed in the laminated absorption layer and the design of the f value (f number) of the lens element.

  The method for manufacturing an image sensor according to an embodiment can manufacture a precise image sensor using a material capable of ultraviolet patterning. Further, the method for manufacturing the image sensor can manufacture an ultra-thin lens. The diameter of the diaphragm formed in the absorption layer can be made different for each absorption layer, and the viewing angle through which light enters can be adjusted. The focal length due to the height of the spacer and the curvature of the lens element can also be changed according to the design.

  In an image sensor according to an embodiment, a viewing angle with respect to each detection element is adjusted through a design of a block layer and a lens element that provide light to each detection element included in the sensor array. The image sensor can acquire a plurality of divided images using a plurality of detection elements. The image sensor can acquire a divided image having the adjusted degree of superimposition by adjusting the viewing angle according to the design of the block layer or the like described above. The image sensor can improve the MTF for a high-quality ultra-thin camera or extract 3D depth information for a three-dimensional camera.

  The apparatus described above may be implemented as a hardware component, a software component, or a combination of hardware and software components. For example, the apparatus and components described in this embodiment include, for example, a processor, a controller, an ALU (arithmetic logic unit), a digital signal processor (digital signal processor), a microcomputer, an FPA (field programmable array), and a PLU (programmable logarithm). It may be implemented using one or more general purpose or special purpose computers, such as units, microprocessors, or different devices that execute and respond to instructions. The processing device executes an operating system (OS) and one or more software applications running on the operating system. The processing device also accesses, stores, manipulates, processes, and generates data in response to software execution. For convenience of understanding, one processing device may be described as being used, but those having ordinary skill in the art may recognize that a processing device may have multiple processing elements and / or It is understood that multiple types of processing elements are included. For example, the processing device includes a plurality of processors or one processor and one controller. Other processing configurations are also possible, such as a parallel processor.

  Software includes computer programs, code, instructions, or a combination of one or more of them, and can configure a processor to operate as desired, or can instruct a processor independently or in combination . Software and / or data may be interpreted by the processing device or provide instructions or data to the processing device, any type of machine, component, physical device, virtual device, computer storage medium or device, Alternatively, it can be embodied permanently or temporarily in the transmitted signal wave. Software is distributed over computer systems coupled to a network and may be stored and executed in a distributed manner. Software and data may be stored on one or more computer readable recording media.

  The method according to the present embodiment is embodied in the form of program instructions executed via various computer means and recorded on a computer-readable recording medium. The recording medium includes program instructions, data files, data structures, etc. alone or in combination. The recording medium and the program instructions may be specially designed and configured for the purpose of the present invention, and may be known and usable by those skilled in the art having computer software technology. . Examples of computer-readable recording media include magnetic media such as hard disks, floppy (registered trademark) disks and magnetic tapes, optical recording media such as CD-ROMs and DVDs, and magneto-opticals such as floppy disks. Media and hardware devices specially configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language code generated by a compiler but also high-level language code executed by a computer using an interpreter or the like. A hardware device may be configured to operate as one or more software modules to perform the operations illustrated in the present invention, and vice versa.

  Although the embodiments have been described with reference to the limited drawings as described above, various technical modifications and variations can be applied based on the above description as long as the person has ordinary knowledge in the art. . For example, the described techniques may be performed in a different order than the described method, and / or components of the described system, structure, apparatus, circuit, etc. may be combined or differently configured from the described method. Appropriate results can be achieved even if they are combined and replaced or replaced by other components or equivalents.

  Therefore, the scope of the present invention is not limited to the disclosed embodiments, but is defined by the claims and equivalents of the claims.

100: Image sensor 110: Lens element 120: Block layer 130: Transparent substrate 140: Detection element 150: Spacer 190: Camera chip

Claims (32)

In the image sensor,
A block layer including an absorption layer and a transparent layer, and allowing light received from the outside to pass through an opening formed in the absorption layer and the transparent layer;
A lens element that transmits the light to the detection element;
Including image sensor.   The image sensor according to claim 1, wherein the detection element is separated from the lens element and receives light that has passed through the opening and the lens element.   The image sensor according to claim 1, wherein the lens element refracts the light to form a focal point on the detection element.   The image sensor according to claim 1, wherein the block layer is separated from the detection element by a focal length of the lens element.   The image sensor according to claim 1, further comprising a transparent substrate that allows light to pass through.   The image sensor according to claim 1, wherein the opening is formed to be aligned with respect to the arrangement of the lens elements in the block layer.   The image sensor according to claim 1, further comprising a spacer that maintains a distance between the block layer and the detection element.   The image sensor according to claim 1, wherein the absorption layer and the transparent layer are alternately arranged in the block layer.   The image sensor according to claim 1, wherein the absorption layer includes a diaphragm formed in a circular region centered on a point corresponding to the lens element. The absorbing layer includes a first diameter stop formed around a point corresponding to the lens element;
The image sensor according to claim 1, wherein the block layer further includes a different absorption layer in which a diaphragm having a second diameter different from the first diameter is formed.   The image sensor according to claim 1, wherein the diameter of the opening gradually changes from one surface of the block layer to another surface of the block layer.   The image sensor according to claim 1, wherein the transparent layer transmits light in a predetermined wavelength band.   The image sensor according to claim 1, wherein the block layer has a height determined based on a predetermined viewing angle.   The image sensor according to claim 1, wherein the block layer includes a number of absorption layers determined based on a predetermined viewing angle (FOV). The diameter of the opening is based on a predetermined amount of light,
The image sensor according to claim 1, wherein the block layer is separated from the detection element by a focal length determined based on the predetermined light amount.   The image sensor according to claim 1, wherein the transparent layer includes a transparent polymer that transmits light.   The image sensor according to claim 1, wherein the absorption layer includes a black matrix material that absorbs light. The block layer includes a plurality of absorption layers,
The circular diaphragm formed in each of the plurality of absorption layers has a diameter determined based on a transparent substrate disposed on the block layer and a refractive index of the transparent layer and a predetermined viewing angle. The image sensor according to claim 1. The lens element and the detection element are arranged in a planar array pattern,
The image sensor according to claim 1, wherein the absorption layer includes a diaphragm formed in alignment with the planar array pattern. The transparent substrate is disposed on a first side of the block layer;
The image sensor according to claim 5, wherein the lens element is disposed on a second side of the block layer that is opposite to the first side. In the manufacturing method of the image sensor,
Providing a transparent substrate;
Providing a block layer including an absorbent layer and a transparent layer;
Providing a lens element according to a pattern in which an opening is formed in the block layer;
Of manufacturing an image sensor. In the image sensor manufacturing method,
Disposing a block layer including a transparent layer and an absorption layer on a transparent substrate;
Providing a lens element corresponding to a pattern of openings formed in the block layer;
An image sensor manufacturing method comprising: The step of arranging the block layer includes:
Coating the transparent substrate with an opaque polymer;
Disposing a mask comprising the pattern on a plurality of portions of the opaque polymer;
Irradiating the opaque polymer exposed according to the pattern of the mask with ultraviolet rays;
Removing the portions of the opaque polymer covered by the mask;
Coating a transparent layer comprising a negative photoresist between and on the remaining opaque polymer;
Exposing the transparent layer to ultraviolet light;
The image sensor manufacturing method according to claim 22, comprising:   The image sensor manufacturing method according to claim 23, further comprising a step of strengthening a bond between the remaining opaque polymer and the transparent layer by performing a hydrophilic treatment.   The image sensor manufacturing method according to claim 23, wherein the mask includes a circular mask made of a lattice pattern.   The image sensor manufacturing method according to claim 23, wherein the absorption layer includes a negative photoresist. Providing the lens element comprises:
Coating a thermoplastic polymer layer comprising a positive photoresist on the block layer;
Disposing a mask comprising the pattern on a plurality of portions of the thermoplastic polymer layer;
Exposing the thermoplastic polymer layer to ultraviolet light in accordance with the pattern of the mask;
Dissolving a portion of the thermoplastic polymer layer exposed to ultraviolet light with a developer to pattern the thermoplastic polymer layer;
Applying a hydrophobic coating to the patterned thermoplastic polymer layer;
Heating the hydrophobically coated thermoplastic polymer layer to form a spherical lens;
The image sensor manufacturing method according to claim 22, comprising:   The image sensor manufacturing method according to claim 27, wherein the thermoplastic polymer layer includes a transparent material that is deformable by heat. In the image sensor,
A block layer including an absorbent layer and a transparent layer stacked together in alternating;
An opening formed in the transparent layer and the absorbing layer to transmit light to the lens element;
A detection element spaced from the lens element and configured to receive light from the lens element;
Including image sensor.   30. The image sensor according to claim 29, wherein a diameter of the opening gradually changes between both surfaces of the block layer. The opening includes a circular aperture in each of the absorbing layers;
30. The image sensor according to claim 29, wherein the diameter of the circular aperture is based on a viewing angle, a transparent substrate disposed on the block layer, and a refractive index of the transparent layer. A spacer located at an outer boundary of the detection element and the block layer;
30. The image sensor of claim 29, wherein the spacer is configured to maintain substantially the same spacing as the focal length of the lens element between the block layer and the detection element.