Image sensor and method of manufacturing the same

Abstract

An image sensor and a method for manufacturing the image sensor are provided. The image sensor comprises: a blocking layer including an absorption layer and a transparent layer; a lens element is located below the blocking layer; and a sensing element is arranged to face the lens element.

Description

[0001] This application claims the benefit of Korean Patent Application No. 10-2018-0039290 filed on April 4, 2018, in the Korean Intellectual Property Office, and Korean Patent Application No. 10-2018-0074099 filed on June 27, 2018, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein in their entirety by reference for all purposes. Technical Field

[0002] The following description relates to an image sensor and a method of manufacturing the image sensor. Background Art

[0003] An image sensor is a device configured to capture an image of an object, and can convert an optical signal including image information of the object into an electrical signal. Image sensors are included in various electronic devices. For example, image sensors such as a charge coupled device (CCD) image sensor and a complementary metal oxide semiconductor (CMOS) image sensor are widely used.

[0004] The CMOS image sensor includes a plurality of pixels including a plurality of transistors and a photoelectric conversion device. A signal photoelectrically converted by the photoelectric conversion device may be processed and output by the plurality of transistors, and image data may be generated based on the pixel signal output from the pixel. Each of the plurality of pixels may photoelectrically convert light or color within a wavelength range to generate and output a signal. Summary of the invention

[0005] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0006] In one general aspect, an image sensor is provided, comprising: a blocking layer including an absorption layer and a transparent layer, the blocking layer being configured to transmit light through openings formed in the absorption layer and the transparent layer; and a lens element being configured to transmit light to a sensing element.

[0007] The sensing element may be spaced apart from the lens element, the sensing element being configured to receive light passing through the opening portion and the lens element.

[0008] The lens element may be configured to refract light and form a focus on the sensing element.

[0009] The barrier layer may be spaced apart from the sensing element by the focal length of the lens element.

[0010] The image sensor may include a transparent substrate configured to transmit light.

[0011] The openings may be located in the barrier layer to correspond to the arrangement of the lens elements.

[0012] The image sensor may include a spacer configured to maintain a space between the blocking layer and the sensing element.

[0013] The absorbent layers and the transparent layers may be arranged alternately in the barrier layer.

[0014] The absorbing layer may include a circular iris opening centered at a point corresponding to the lens element.

[0015] The absorbing layer may include an iris opening having a first diameter centered at a point corresponding to the lens element, and the blocking layer may include another absorbing layer, wherein the other absorbing layer includes another iris opening having a second diameter different from the first diameter.

[0016] The diameter of the opening may gradually change from one surface to the other surface of the barrier layer.

[0017] The transparent layer may be configured to transmit light within a wavelength band.

[0018] The blocking layer may have a height based on the field of view (FOV).

[0019] The number of absorbing layers stacked in the barrier layer may be determined based on the field of view (FOV).

[0020] The diameter of the opening may be based on the amount of light, and the distance between the blocking layer and the sensing element may be determined based on a focal distance determined by the amount of light.

[0021] The transparent layer may include a transparent polymer configured to transmit light.

[0022] The absorption layer may include a black matrix material configured to absorb light.

[0023] The blocking layer may include a plurality of absorbing layers, and the circular iris opening formed in each of the plurality of absorbing layers may have a diameter determined based on a field of view (FOV), a refractive index determined by a transparent layer and a transparent substrate disposed on the blocking layer.

[0024] The lens elements and the sensing elements may be arranged in a planar array pattern, and the absorption layer may include iris openings arranged based on the planar array pattern.

[0025] The transparent substrate may be disposed on a first side of the barrier layer and the lens element may be disposed on a second side of the barrier layer opposite the first side.

[0026] In another general aspect, a method of manufacturing an image sensor is provided, the method comprising: providing a transparent substrate; providing a barrier layer including an absorption layer and a transparent layer; and providing a lens element based on a pattern of openings formed in the barrier layer.

[0027] In another general aspect, a method of manufacturing an image sensor includes providing a barrier layer including an absorption layer and a transparent layer on a transparent substrate; and providing a lens element corresponding to a pattern of openings formed in the barrier layer.

[0028] The step of setting a blocking layer may include: coating a transparent substrate with an opaque polymer; setting a mask having a pattern on a portion of the opaque polymer; emitting ultraviolet (UV) rays to the opaque polymer exposed by the mask pattern; removing the portion of the opaque polymer covered with the mask; coating a transparent layer on and between the remaining opaque polymer, the transparent layer may include a transparent layer of a negative photoresist; and exposing the transparent layer to ultraviolet rays.

[0029] The method may include increasing bonding between the transparent layer and the remaining opaque polymer by performing a hydrophilic treatment.

[0030] The mask may include a circular mask having a grid pattern.

[0031] The coating may include a negative photoresist.

[0032] The step of setting a lens element may include: coating a thermoplastic polymer layer on a barrier layer, the thermoplastic polymer layer may include a positive photoresist; setting a mask having a pattern on a portion of the thermoplastic polymer layer; exposing the thermoplastic polymer layer to ultraviolet (UV) light through the pattern of the mask; dissolving the thermoplastic polymer layer exposed to the UV light by a developer; applying a hydrophobic coating to the patterned thermoplastic polymer layer; and heating the coated thermoplastic polymer layer to form a spherical lens.

[0033] The thermoplastic polymer layer may include a transparent material that is formable by heating.

[0034] In another general aspect, an image sensor is provided, comprising: a blocking layer including an absorption layer and a transparent layer alternately stacked together; an opening portion formed in the absorption layer and the transparent layer to transmit light to a lens element; and a sensing element spaced apart from the lens element and configured to receive light from the lens element.

[0035] The diameter of the opening may gradually change between two opposing surfaces of the barrier layer.

[0036] The opening portion may include a circular opening of each of the plurality of absorption layers, a diameter of the circular opening being based on a field of view (FOV) and a refractive index determined by the transparent layer and a transparent substrate disposed on the blocking layer.

[0037] The image sensor may include a spacer located at an outer boundary of the blocking layer and the sensing element, the spacer being configured to maintain a spacing substantially equal to a focal length of the lens element between the blocking layer and the sensing element.

[0038] Other features and aspects will be apparent from the following detailed description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 An example of the configuration of an image sensor is shown.

[0040] Figure 2 Examples of barrier layers and lens elements are shown.

[0041] Figure 3 Examples of cross sections of barrier layers and lens elements are shown.

[0042] Figure 4 An example of the field of view (FOV) of an image sensor is shown.

[0043] Figure 5 An example of the FOV determined by the aperture of the barrier layer is shown.

[0044] Figure 6 Another example of the FOV determined by the opening of the blocking layer is shown.

[0045] Figure 7 is a diagram illustrating an example of a method of manufacturing an image sensor.

[0046] Figure 8 An example of providing a barrier layer is shown.

[0047] Fig. 9 An example of a method of arranging lens elements is shown.

[0048] Fig.10 An example of an image obtained by capturing a structure in which a lens element is integrated on one surface of a barrier layer using an electron scanning electron microscope is shown.

[0049] Fig.11 An example of an image obtained by capturing a structure in which a lens element is integrated on one surface of a barrier layer using an optical microscope is shown.

[0050] Fig.12 An example of transmittance of light based on the number of absorption layers included in the blocking layer is shown.

[0051] Fig.13 An example of an image obtained by capturing the upper surface and side surfaces of an image sensor using a confocal laser scanning microscope is shown.

[0052] Fig.14 An example of intensity distribution of an image sensor is shown.

[0053] Fig.15An example of an image acquired by an image sensor is shown.

[0054] Fig.16 An example of a result obtained by measuring the FOV of an image sensor is shown.

[0055] Fig.17 and Fig.18 An example showing the effect of a barrier layer on the modulation transfer function (MTF).

[0056] Throughout the drawings and detailed description, unless otherwise described or provided, the same figure reference numerals will be understood to refer to the same elements, features and structures. The drawings may not be drawn to scale, and the relative sizes, proportions and descriptions of the elements in the drawings may be exaggerated for clarity, illustration and convenience. DETAILED DESCRIPTION

[0057] The following detailed description is provided to help the reader obtain a comprehensive understanding of the methods, devices and / or systems described herein. However, various changes, modifications and equivalents of the methods, devices and / or systems described herein will be clear after understanding the disclosure of the present application. For example, the order of operations described herein is only an example, and the order of operations is not limited to the order set forth herein, but can be changed as will be clear after understanding the disclosure of the present application, except for operations that must occur in a specific order. In addition, for greater clarity and simplicity, the description of features known in the art may be omitted.

[0058] The features described herein may be implemented in different forms and should not be interpreted as being limited to the examples described herein. Rather, the examples described herein are provided only to illustrate some of the many possible ways to implement the methods, devices and / or systems described herein, which will be clear after understanding the disclosure of this application.

[0059] Hereinafter, examples will be described in detail with reference to the accompanying drawings. However, the scope of the rights should not be understood to be limited to the examples set forth herein. Various modifications may be made to the examples. Here, the examples are not interpreted as being limited to the present disclosure, and should be understood to include all changes, equivalents, and substitutes within the conceptual and technical scope of the present disclosure.

[0060] The terms used herein are for the purpose of describing specific examples only and are not intended to be limiting. As used herein, unless the context clearly indicates otherwise, the singular is intended to include the plural. As used herein, the term "and / or" includes any one of the associated listed items or any combination of any two or more of the associated listed items.

[0061] Although the terms "first" or "second" are used to explain various components, the components are not limited to the terms. These terms should only be used to distinguish one component from another. For example, within the scope of the rights according to the concept of the present disclosure, a "first" component may be referred to as a "second" component, or similarly, a "second" component may be referred to as a "first" component. It will be understood that when a component is referred to as being "connected to" another component, the component may be directly connected or coupled to the other component or there may be intermediate components.

[0062] The use of the term "may" with respect to an example or embodiment herein (e.g., the term "may" with respect to what an example or embodiment may include or implement) means that there is at least one example or embodiment that includes or implements such a feature, while all examples and embodiments are not limited thereto.

[0063] With regard to the reference numerals assigned to the elements in the drawings, it should be noted that, wherever possible, the same elements will be represented by the same reference numerals even if they are shown in different drawings. In addition, in the description of the examples, when it is considered that a detailed description of a well-known related structure or function will lead to an obscure interpretation of the present disclosure, such description will be omitted.

[0064] Figure 1 An example of the configuration of the image sensor 100 is shown.

[0065] The image sensor 100 is a device for capturing an image of an object. In one example, the image sensor 100 includes a lens element 110 , a barrier layer 120 , a transparent substrate 130 , a sensing element 140 , a spacer 150 , and a camera chip 190 .

[0066] The lens element 110 is an element that refracts light received from the outside and gathers the light. The lens element 110 refracts the light to form a focus on the sensing element 140. In one example, one surface of the lens element 110 has a protrusion, and the other surface is a flat surface. In one example, the lens element 110 is a microlens with a convex surface. Without departing from the spirit and scope of the described illustrative examples, other shapes of the surface of the lens element 110 with a protrusion (such as, for example, a spherical, aspherical, concave lens, or Fresnel shape) may be used.

[0067] A group of lens elements 110 is referred to as a lens array. For example, a lens array includes a plurality of lens elements arranged in a planar array pattern such as, for example, a grid pattern.

[0068] The blocking layer 120 is a layer that blocks light. In one example, the blocking layer 120 includes a transparent layer and an absorption layer forming a pattern (e.g., a hole pattern). In one example, the blocking layer 120 includes an opening portion formed by the pattern of the absorption layer. The blocking layer 120 transmits light received from the outside to the lens element 110 through the opening portion. Figure 2 and Figure 3 Examples of the transparent layer and the absorption layer included in the blocking layer 120 are further described.

[0069] The transparent substrate 130 is a transparent substrate configured to transmit light. In one example, the transparent substrate 130 is disposed on the barrier layer 120. However, the arrangement of the transparent substrate 130 is not limited thereto, and the transparent substrate 130 is also disposed on the lens element 110 located on the barrier layer 120. In one example, the transparent substrate 130 includes a glass wafer, however, the type of the transparent substrate 130 is not limited thereto. Other types of transparent substrates 130 may be used without departing from the spirit and scope of the described illustrative examples.

[0070] In one example, the sensing element 140 is spaced apart from the lens element 110 and receives light passing through the opening of the barrier layer 120 and the lens element 110. The sensing element 140 receives light gathered by the lens element 110 after the light passes through the transparent substrate 130 and the opening of the barrier layer 120. The sensing element 140 outputs a signal indicating the intensity of the received light. In one example, the sensing element 140 senses light corresponding to a color channel and outputs a signal indicating the intensity of the corresponding color. The color channel is a channel representing a color corresponding to a portion of the visible region, and includes, for example, a red channel, a green channel, and a blue channel. In one example, a separate sensing element 140 senses light corresponding to one of the red channel, the green channel, and the blue channel. The wavelength that the sensing element 140 can sense is not limited to the visible region. In other examples, the sensing element 140 can sense infrared or ultraviolet rays according to the design.

[0071] A group of sensing elements 140 is referred to as a sensor array. For example, the sensor array includes a plurality of sensing elements arranged in a planar array pattern (e.g., a grid pattern). In one example, the sensor array includes a sensing element 140 that senses red, a sensing element 140 that senses green, and a sensing element 140 that senses blue. In one example, the sensor array can sense three colors distinguishably.

[0072] The spacer 150 maintains the interval between the barrier layer 120 and the sensing element 140. Here, maintaining the interval between the barrier layer 120 and the sensing element 140 may be understood as maintaining the interval between the barrier layer 120 and the sensing element 140 within a predetermined range of a predetermined value. For example, the spacer 150 supports the barrier layer 120 and the sensing element 140. Figure 1 As shown in FIG. 1 , in one example, spacers 150 are arranged along the outer boundary of the sensor array and support the outer boundary of barrier layer 120 .

[0073] The camera chip 190 is a chip that implements a sensor array. For example, the camera chip 190 is implemented at a wafer level.

[0074] In one example, the lens element 110 , the barrier layer 120 , the transparent substrate 130 , the sensing element 140 , the spacer 150 , and the camera chip 190 are combined by an integration process.

[0075] Figure 2 Examples of barrier layer 220 and lens element 210 are shown.

[0076] The blocking layer 220 includes an absorption layer 221 and a transparent layer 222. The blocking layer 220 transmits light received from the outside through openings 229 formed in the absorption layer 221 and the transparent layer 222. In one example, the blocking layer 220 provides the lens element 210 with light received from the outside through the openings 229.

[0077] The absorption layer 221 is a layer that absorbs light and is re-referred to as, for example, a "light absorption layer". In one example, the absorption layer 221 includes a black matrix material that absorbs light. For example, the black matrix material includes black SU-8. However, the material of the absorption layer 221 is not limited thereto, and in another example, the absorption layer 221 includes a negative photoresist that absorbs light. In one example, the absorption layer 221 includes a circular iris opening formed with a point corresponding to the lens element 210 as the center based on the arrangement of the lens element 210. The absorption layer 221 includes an iris opening formed and arranged based on a planar array pattern.

[0078] The transparent layer 222 is a layer that transmits light. In one example, the transparent layer 222 includes a transparent polymer that transmits light. For example, the transparent polymer includes SU-8. However, the material of the transparent layer 222 is not limited thereto, and the transparent layer 222 includes any negative photoresist that transmits light. In one example, the transparent layer 222 transmits light within a band. In another example, the transparent layer 222 transmits light within the visible light band.

[0079] In one example, the barrier layer 220 forms the opening 229 by a structure in which the absorption layer 221 and the transparent layer 222 are alternately arranged. In one example, the surface of the barrier layer 220 where the absorption layer 221 is arranged is opposite to the surface of the barrier layer 220 where the lens element 210 is arranged. However, the arrangement of the absorption layer 221 is not limited thereto, and the absorption layer 221 and the lens element 210 are located on the same surface.

[0080] The circular iris openings are formed in a grid pattern in the absorption layer 221. For example, when the barrier layer 220 includes a plurality of absorption layers, the iris openings of the plurality of absorption layers form an opening portion 229. The opening portion 229 is a portion of the barrier layer 220 through which light passes. The opening portion 229 is formed based on the arrangement of the lens elements 210 in the barrier layer 220. Figure 3 The opening portion 229 is further described.

[0081] The lens element 210 transmits light received from the outside to the sensing element. In one example, the lens element 210 is located below the barrier layer 220 and transmits the light provided through the opening 229. In one example, a protrusion is formed on one surface of the lens element 210, and the protrusion is arranged so that the protrusion faces the sensing element. For example, the lens element 210 transmits the light provided through the opening 229 to the sensing element corresponding to the opening 229. However, the above structure is only an example, and the example is not limited thereto. In another example, the lens element 210 is located above the barrier layer 220, rather than below the barrier layer 220, or the lens element 210 is located above and below the barrier layer 220. In another example, a flat portion of the lens element 210 is arranged to face the sensing element instead of the protrusion. In another example, the lens element 210 has a concave portion formed on the surface instead of the protrusion.

[0082] The pattern (e.g., hole pattern) formed in the blocking layer 220 allows light passing through the opening 229 in the blocking layer 220 to be transmitted to the sensing element corresponding to the opening 229 and prevents the light from propagating toward another sensing element. Therefore, the blocking layer 220 having the pattern reduces optical crosstalk. In addition, for example, a wide field of view (FOV) of the image sensor is designed based on the diameter of the hole pattern or the height of the blocking layer 220.

[0083] Figure 3 Examples of cross-sections of barrier layer 320 and lens element 310 are shown.

[0084] The image sensor includes a lens element 310 located below a barrier layer 320 and a barrier layer 320 forming an opening 329. Figure 3 As shown in FIG. 3 , the barrier layer 320 has a structure in which absorption layers 321 and transparent layers 322 are alternately stacked. The absorption layer 321 alone includes a circular iris opening, and the circular iris opening is filled with the same material as that of the transparent layer 322.

[0085] In the absorption layer 321, the area where the iris opening is formed transmits light, while the other area where the iris opening is not formed absorbs light. The light that passes through the iris opening of any absorption layer 321 passes through the next transparent layer 322. The light that passes through the next transparent layer 322 passes through the iris opening of the next absorption layer. Therefore, the iris opening of each absorption layer in the plurality of absorption layers forms an opening portion 329 that has a cylindrical shape and transmits light received from the outside.

[0086] The light passing through the opening portion 329 is provided to the lens element 310. The lens element 310 collects the light passing through the opening portion 329 and transmits the light to the sensing element.

[0087] Figure 4 An example of the FOV of an image sensor is shown.

[0088] The blocking layer 420 has a height H determined based on the FOV. For example, the FOV of the image sensor represents a maximum angle θ at which light received from the outside reaches the sensing element relative to the transparent substrate 430. 1 The light incident to the transparent substrate 430 is refracted based on the refractive index of each of the transparent substrate 430 and the transparent layer 422. For example, Figure 4 In the example, assume that the light is at an angle θ 1 The light is incident on the transparent substrate 430. Since the light is absorbed by the absorption layer 421 in the blocking layer 420, the maximum angle θ at which the light is allowed to pass through the blocking layer 420 through the opening is 2 For example, the maximum angle θ of the light received from the outside that is allowed to pass through the blocking layer 420 is 2 The height H of the opening portion corresponds to the height H of the barrier layer 420.

[0089] In one example, the angle θ in the image sensor is shown in Table 1 below: 1 and angle θ 2 and the height H of the barrier layer 420 .

[0090] [Table 1]

[0091] H(μm) <![CDATA[θ 2 (°)]]> <![CDATA[θ 1 (°)]]> 120 22.61 33.92 110 24.44 36.66 100 26.56 39.84 90 29.054 43.58 80 32.00 48.00 70 35.53 53.30 60 39.80 59.70 50 45 67.5 40 51.340 77.01 30 59.036 88.55 20 68.198 77.7

[0092] In Table 1, when the height H of the blocking layer 420 is 110 μm, the FOV of the image sensor is about 70°.

[0093] However, the configuration of the barrier layer 420 is not limited to the above description. The number of the absorption layers 421 stacked in the barrier layer 420 is determined based on the FOV. For example, the height of the barrier layer 420 is determined based on the FOV, and the number of the stacked absorption layers 421 is determined based on the intervals between the absorption layers 421 and the height of the barrier layer 420. The intervals between the absorption layers 421 correspond to the thickness of the transparent layer 422.

[0094] Figure 5 An example of the FOV determined by the opening of the barrier layer is shown.

[0095] In one example, the barrier layer 520 includes an absorption layer 521, wherein the absorption layer 521 includes an iris opening having a first diameter D1 formed at a point corresponding to the lens element 510 as a center. The barrier layer 520 includes a second absorption layer (i.e., absorption layer 522) including an iris opening having a second diameter D2 different from the first diameter D1. The barrier layer 520 includes a third absorption layer (i.e., absorption layer 523) including an iris opening having a third diameter D3 different from the second diameter D2. In one example, the first diameter D1, the second diameter D2, and the third diameter D3 have values ​​that gradually increase or decrease. For example, the barrier layer 520 has a structure in which the diameter of the opening portion 529 gradually changes from one surface of the barrier layer 520 to the other surface of the barrier layer 520. The number of absorption layers in the barrier layer 520 is a non-exhaustive example, and other numbers of absorption layers may be used without departing from the spirit and scope of the described illustrative examples.

[0096] Figure 4 An example of a constant diameter of an opening is shown in FIG. Figure 5 An example is shown in which the diameter of the opening 529 gradually increases. Figure 5 , the diameter of the iris opening formed in the absorption layer gradually increases from the absorption layer close to the lens element 510 to the absorption layer far from the lens element 510. When the diameter of the opening 529 gradually increases, the maximum angle θ allowed for light to pass through the blocking layer 520 through the opening 529 is 2 In this example, based on the desired FOVθ 1 The degree to which the diameter of the opening 529 is increased is determined by the refractive index of the transparent substrate 530 and the refractive index of each of the plurality of transparent layers. 1 The angle at which the refracted light is incident on the blocking layer 520 determines the degree to which the diameter of the opening 529 is increased. The degree to which the diameter of the opening 529 is increased corresponds to the maximum angle θ at which the light is allowed to pass through the blocking layer 520. 2 Thus, the circular iris opening in each of the plurality of absorbing layers formed in the barrier layer 520 has a desired FOVθ based on 1and a diameter determined by a refractive index determined by each of the transparent layer and the transparent substrate 530 .

[0097] In one example, the barrier layer 520 is spaced from the sensing element 540 by the focal length of the lens element 510. Figure 5 As shown in FIG. 5 , the barrier layer 520 is arranged to face the sensing element 540 based on the lens element 510. However, the arrangement of the barrier layer 520 is not limited thereto, and the barrier layer 520 is arranged on the same side as the sensing element 540 based on the lens element 510.

[0098] For example, the opening has a diameter determined based on the amount of light, and the blocking layer 520 and the sensing element 540 are spaced apart by a focal distance determined based on the amount of light.

[0099] Already referred to Figure 5 An example in which the diameter of the opening 529 gradually increases is described below. Figure 6 An example in which the diameter of the opening portion gradually decreases is described.

[0100] Figure 6 Another example of the FOV determined by the opening of the blocking layer is shown.

[0101] The blocking layer 620 includes, based on the lens element 610, a first absorption layer 621 including an iris opening having a first diameter D1, a second absorption layer 622 including an iris opening having a second diameter D2, and a third absorption layer 623 including an iris opening having a third diameter D3. The first diameter D1, the second diameter D2, and the third diameter D3 have gradually decreasing values. For example, the blocking layer 620 has a structure in which the diameter of the opening portion 629 gradually decreases from one surface of the blocking layer 620 to the other surface of the blocking layer 620. Therefore, based on the above structure, the image sensor allows a distant object to be observed larger.

[0102] Figure 7 is a diagram showing an example of a method for manufacturing an image sensor. The steps may be performed in the order and manner shown. Figure 7 However, the order of some operations may be changed or some operations may be omitted without departing from the spirit and scope of the described illustrative examples. Figure 7 Many of the operations shown in can be performed in parallel or simultaneously. Figure 7 One or more blocks and combinations of blocks may be implemented by a computer based on dedicated hardware or a combination of dedicated hardware and computer instructions that perform specific functions. Figure 7 In addition to the description, Figures 1 to 6 The description also applies to Figure 7 , and is incorporated herein by reference. Therefore, the above description may not be repeated here.

[0103] In one example, an image sensor is formed by sequentially stacking a transparent substrate, a barrier layer, a lens element, and a sensing element.

[0104] Reference Figure 7 In operation 710, a transparent substrate is provided. The transparent substrate is a glass wafer as described above, however, examples are not limited thereto.

[0105] In operation 720, a barrier layer including an absorption layer and a transparent layer is provided. For example, the barrier layer is provided on a transparent substrate. In one example, as described above, the absorption layer and the transparent layer are alternately stacked. Figure 8 An example of forming the barrier layer is further described.

[0106] In operation 730, a lens element is disposed based on the pattern of the openings formed in the barrier layer. For example, the lens element is disposed on the barrier layer. Fig. 9 An example in which a microlens array is provided as a lens element is further described.

[0107] Figure 8 An example of providing a barrier layer is shown.

[0108] Reference Figure 8 In operation 821, an absorption layer is disposed on a transparent substrate. For example, the transparent substrate is coated with an opaque polymer such as a black polymer (eg, black SU-8) as the absorption layer.

[0109] In operation 822, a mask is aligned on the absorption layer. In one example, the mask is arranged on the absorption layer in a planar array pattern. For example, a circular mask is arranged based on a grid pattern. Ultraviolet (UV) light is emitted to the mask aligned on the absorption layer. Portions of the absorption layer other than the mask are exposed to the ultraviolet light. The absorption layer includes a negative photoresist. The photoresist is a photosensitive material used in various processes and forms a patterned coating on a surface.

[0110] In operation 823, the absorbing layer patterned by UV exposure is developed by a developer. In one example, a solvent called a "developer" is applied to the surface. The portion of the negative photoresist exposed to the UV light is insoluble in the developer. The portion of the negative photoresist not exposed to the UV light is dissolved by the photoresist developer. Therefore, as Figure 8 As shown in , a portion of the absorption layer corresponding to the shape of the mask is dissolved and removed.

[0111] In operation 824, the patterned absorbing layer is coated with a transparent layer. With the transparent layer coated on the patterned absorbing layer, the barrier layer is exposed to ultraviolet light. The transparent layer also includes a negative photoresist, and the portion of the transparent layer exposed to ultraviolet light is insoluble in a developer. Because all portions of the transparent layer are exposed to ultraviolet light without a mask, the transparent layer is fixed. In one example, the transparent layer including the negative photoresist is coated on top of and between the remaining (or undissolved) opaque polymer.

[0112] In operation 825, a hydrophilic treatment is applied to the transparent layer. Through the hydrophilic treatment, the bonding force between the transparent layer and the absorption layer is increased. For example, the hydrophilic treatment is an oxygen plasma treatment.

[0113] In operation 826, a plurality of layers (e.g., "N" layers) are stacked by repeating operations 821 to 825. "N" is an integer greater than or equal to "2". The absorption layer and the transparent layer are alternately stacked. While repeating operations 821 to 825, the alignment between the patterns formed for the absorption layer is maintained. Therefore, a set of iris openings formed for the absorption layer corresponds to the opening portion.

[0114] Fig. 9 An example of arranging lens elements is shown.

[0115] Reference Fig. 9 In operation 931, a thermoplastic polymer (or a thermoplastic polymer layer) is disposed on the barrier layer. Thermoplastic polymer is a transparent material used to make a lens and is a material that can be molded by heating. For example, the thermoplastic polymer is AZ9260.

[0116] In operation 932, a mask arranged in a pattern about the planar array pattern formed on the absorption layer is disposed on the thermoplastic polymer. In the case where the mask is arranged on the thermoplastic polymer, the thermoplastic polymer is exposed to ultraviolet light. In other words, the thermoplastic polymer is exposed to ultraviolet (UV) light through the pattern of the mask.

[0117] In operation 933, the thermoplastic polymer patterned by UV exposure is developed by a developer. For example, if the thermoplastic polymer is a positive photoresist, the portion of the positive photoresist exposed to UV light is dissolved by the photoresist developer. The portion of the positive photoresist not exposed to UV light is insoluble in the developer. Therefore, if Fig. 9 As shown in , the portion of the thermoplastic polymer corresponding to the shape of the mask remains unchanged after UV exposure. For example, when a circular mask is used, the thermoplastic polymer remains in the form of a cylinder based on the planar array pattern.

[0118] In operation 934, a hydrophobic coating 901 (eg, a fluorocarbon nanofilm coating) is applied to the patterned structure of the thermoplastic polymer. The hydrophobic coating 901 increases the cohesion of the thermoplastic polymer.

[0119] In operation 935, a microlens array is manufactured by a thermal reflow process. Since the cohesive force of the thermoplastic polymer is increased by the hydrophobic coating 901 of operation 934, the thermoplastic polymer is aggregated in the form of a sphere.

[0120] However, the example of manufacturing the image sensor is not limited to Figures 7 to 9 , and may vary according to design. In addition, the above reference Figures 7 to 9 The operation order of each of the described multiple manufacturing processes is not limited to the above description, and the order may be changed. In some embodiments, a part of the process may be omitted or added.

[0121] Fig.10 An example of an image obtained by capturing a structure in which a lens element is integrated on one surface of a barrier layer using an electron scanning electron microscope is shown.

[0122] Fig.10 Shows the lens elements captured by a scanning electron microscope. Fig.10 In the embodiment, spherical lens elements are uniformly formed in a grid pattern below the barrier layer.

[0123] Fig.11 An example of an image obtained by capturing a structure in which a lens element is integrated on one surface of a barrier layer using an optical microscope is shown.

[0124] Fig.11 shows a lens element captured by an optical microscope. Fig.11 In the figure, the focal points of the lens elements are uniformly formed and are represented by white dots.

[0125] Fig.12 An example of transmittance of light based on the number of absorption layers included in the blocking layer is shown.

[0126] Fig.12 Results indicating that the transmittance of light passing through the barrier layer decreases as the number of absorption layers included in the barrier layer increases are shown. For example, when coating of a 4.5 μm absorption layer is performed, about 40% to 50% of light is transmitted through a single layer. About 10% of light is transmitted through two layers. Light in the visible light region is hardly transmitted through four layers.

[0127] Fig.13 An example of an image acquired by capturing an upper surface (eg, a plane formed by the x-axis and the y-axis) and a side surface (eg, a plane formed by the x-axis and the z-axis) of an image sensor using a confocal laser scanning microscope is shown.

[0128] Acquired using confocal laser scanning microscopy Fig.13 The images represent a structure without a lens array (w / o MLA) 1310, a structure without a barrier layer (w / o MBL) 1320, and a structure with a lens array and a barrier layer (w MLA+MBL) 1330.

[0129] In structure 1310, the path of light is not focused. In structure 1320, light is not blocked.

[0130] In the structure 1330, the path of light is focused and the light is blocked in a portion other than the opening portion.

[0131] Fig.14 An example of intensity distribution of an image sensor is shown.

[0132] Fig.14 Show Fig.13 The comparison results of the intensity distribution of structure 1310 to structure 1330 are shown in FIG. Fig.14 In the figure, the dashed line w / oMLA represents the intensity distribution without the microlens array, the dashed line w / oMBL represents the intensity distribution without the multiple blocking layers, and the solid line wMLA+MBL represents the intensity distribution with both the microlens array and the multiple blocking layers. The image sensor can block about 60% of the light more effectively than the structure without the blocking layer. In addition, in terms of focus, the image sensor presents a uniform amount of light. The uniform amount of light indicates that the lens is uniformly manufactured.

[0133] Fig.15 An example of an image acquired by an image sensor is shown.

[0134] By using image sensors to capture Fig.15 The original image shown at the top of Fig.15 The image sensor acquires multiple clear segmented images while using a blocking layer to prevent crosstalk.

[0135] Fig.16 An example of a result obtained by measuring the FOV of an image sensor is shown.

[0136] When an image sensor captures an image of a target object, the FOV of the image sensor is measured from the length of the target object image and the distance that allows a user to observe the image filled with the object and captured by the image sensor. Fig.16 As shown in , the FOV of the image sensor is approximately 70°.

[0137] Fig.17 and Fig.18 An example showing the effect of a barrier layer on the modulation transfer function (MTF).

[0138] Fig.17 17 shows an MTF measurement image of a structure 1710 without a barrier layer, and an MTF measurement image of a structure 1720 with a barrier layer. The MTF measurement image of the structure 1710 has a relatively low definition, whereas the MTF measurement image of the structure 1720 has a relatively high definition. Fig.18 As shown in , for an image sensor having a structure with a blocking layer, the MTF can be measured.

[0139] According to an example, the image sensor disclosed herein is installed in an ultra-thin camera application product (e.g., a mobile digital camera). In addition, the image sensor is applicable to other imaging devices, such as ultra-small optical imaging devices (e.g., an endoscopic camera or a drone).

[0140] According to an example, in an image sensor, an absorption layer for preventing optical crosstalk is arranged to face a sensing element based on a lens element, and an empty space between the lens element and the sensing element is maintained by a spacer. Therefore, a thin image sensor can be realized.

[0141] According to an example, the image sensor uses a barrier layer including an absorption layer and a transparent layer to reduce optical crosstalk. In addition, the FOV of the image sensor is adjusted during the manufacture of the image sensor.

[0142] According to an example, in an image sensor, a lens element is arranged on a lower surface of a barrier layer. Because the barrier layer is arranged on the lens element, optical crosstalk is reduced. In addition, in the image sensor, a transparent substrate is arranged on the barrier layer. Because the transparent substrate is located on the barrier layer, received light is refracted to effectively increase the FOV of the image sensor. The FOV is adjusted based on the thickness of the transparent layer and the number of stacked absorption layers. In addition, the diameter or width of the iris opening formed in one absorption layer is designed to be different from the diameter or width of the iris opening formed in another absorption layer, so the FOV is determined.

[0143] According to an example, an image sensor is integrated in a semiconductor to be used as an ultra-thin camera. In addition, the amount of light received by the image sensor is adjusted by designing the width of an iris opening formed in each of a plurality of stacked absorption layers and the f-number of a lens element.

[0144] According to an example, a method of manufacturing an image sensor enables the manufacture of an accurate image sensor using a material capable of UV patterning. In addition, the method of manufacturing an image sensor enables the manufacture of an ultra-thin lens. An iris opening formed in an absorption layer is set to have different diameters, and thus, the FOV of received light can be adjusted. In addition, the focal length based on the curvature of the lens element and the height of the spacer can be varied according to the design.

[0145] According to an example, the FOV of the image sensor for the individual sensing elements included in the sensor array can be adjusted by designing a lens element and a blocking layer that provide light to the individual sensing elements. The image sensor acquires multiple segmented images using multiple sensing elements. The image sensor acquires segmented images with an adjusted degree of overlap based on the adjustment of the FOV by designing the blocking layer as described above. The image sensor enhances the MTF for a high-quality ultra-thin camera, or extracts 3D depth information for a three-dimensional (3D) camera.

[0146] Although the present disclosure includes specific examples, it will be clear after understanding the disclosure of the present application that various changes in form and detail may be made in these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein will be considered to be descriptive only, not for the purpose of limitation. The description of the features or aspects in each example will be considered to be applicable to similar features or aspects in other examples. If the described techniques are performed in a different order, and / or if the components in the described systems, architectures, devices, or circuits are combined in different ways and / or replaced or supplemented by other components or their equivalents, suitable results may be achieved. Therefore, the scope of the present disclosure is not limited by specific embodiments, but by the claims and their equivalents, and all changes within the scope of the claims and their equivalents will be interpreted as included in the present disclosure.

Claims

1. An image sensor, comprising: a transparent substrate configured to refract light; a blocking layer including an absorption layer and a transparent layer, the blocking layer being configured to transmit light refracted through the transparent substrate through openings formed in the absorption layer and the transparent layer; a lens element configured to collect light transmitted through the opening portion and transmit the collected light to the sensing element, The transparent substrate is arranged on a first side of the barrier layer, and the lens element is arranged on a second side of the barrier layer opposite to the first side.

2. The image sensor according to claim 1, wherein: The sensing element is spaced apart from the lens element, and is configured to receive light passing through the opening portion and the lens element.

3. The image sensor according to claim 1, wherein: The lens element is also configured to refract the light and form a focus on the sensing element.

4. The image sensor according to claim 1, wherein: The barrier layer is spaced from the sensing element by the focal length of the lens element.

5. The image sensor according to claim 1, wherein: The openings are located in the barrier layer to correspond to the arrangement of the lens elements.

6. The image sensor according to claim 1, further comprising: The spacer is configured to maintain a spacing between the barrier layer and the sensing element.

7. The image sensor according to claim 1, wherein: The absorption layers and the transparent layers are arranged alternately in the barrier layer.

8. The image sensor according to claim 1, wherein: The absorbing layer includes a circular iris opening centered at a point corresponding to the lens element.

9. The image sensor according to claim 1, wherein: the absorbing layer includes an iris opening having a first diameter centered at a point corresponding to the lens element, The barrier layer further comprises a further absorbent layer, wherein the further absorbent layer comprises a further iris opening having a second diameter different from the first diameter.

10. The image sensor according to claim 1, wherein: The diameter of the opening gradually changes from one surface to the other surface of the barrier layer.

11. The image sensor according to claim 1, wherein: The transparent layer is configured to transmit light within a wavelength band.

12. The image sensor according to claim 1, wherein: The blocking layer has a height based on the field of view.

13. The image sensor according to claim 1, wherein: The number of absorbing layers stacked in the barrier layer is determined based on the field of view.

14. The image sensor according to claim 1, wherein: The diameter of the opening is based on the amount of light, and the distance between the blocking layer and the sensing element is a focal distance determined based on the amount of light.

15. The image sensor according to claim 1, wherein: The transparent layer includes a transparent polymer configured to transmit light.

16. The image sensor according to claim 1, wherein: The absorbing layer includes a black matrix material configured to absorb light.

17. The image sensor according to claim 1, wherein: The barrier layer includes a plurality of absorbing layers, and the degree to which the diameter of the circular iris opening formed in the plurality of absorbing layers increases from the absorbing layer close to the lens element to the absorbing layer far from the lens element is determined based on the following items: the field of view, the refractive index determined by the transparent layer and the transparent substrate.

18. The image sensor according to claim 1, wherein: The lens elements and sensing elements are arranged in a planar array pattern. The absorbing layer includes iris openings arranged based on a planar array pattern.

19. A method for manufacturing an image sensor, the method comprising: providing a transparent substrate configured to refract light; providing a barrier layer including an absorbent layer and a transparent layer; providing lens elements based on a pattern of openings formed in the barrier layer, wherein the blocking layer is configured to transmit the light refracted by the transparent substrate through the opening portion, and the lens element is configured to collect the light transmitted through the opening portion and transmit the collected light to the sensing element, The transparent substrate is arranged on a first side of the barrier layer, and the lens element is arranged on a second side of the barrier layer opposite to the first side.

20. A method of manufacturing an image sensor, the method comprising: Disposing a barrier layer including an absorption layer and a transparent layer on a transparent substrate; providing a lens element corresponding to the pattern of the openings formed in the barrier layer, wherein the blocking layer is configured to transmit light received from the outside through the opening portion, and the lens element is configured to collect the light transmitted through the opening portion and transmit the collected light to the sensing element, The transparent substrate is arranged on a first side of the barrier layer, and the lens element is arranged on a second side of the barrier layer opposite to the first side.

21. The method according to claim 20, wherein: The steps of setting the barrier layer include: Coating a transparent substrate with an opaque polymer; disposing a mask having a pattern over a portion of the opaque polymer; emitting ultraviolet light to the opaque polymer exposed through the pattern of the mask; removing the portion of the opaque polymer where the mask is disposed; applying a transparent layer comprising a negative photoresist over and between the remaining opaque polymer; The clear layer is exposed to ultraviolet light.

22. The method according to claim 21, further comprising: The bonding force between the transparent layer and the remaining opaque polymer is increased by performing a hydrophilic treatment.

23. The method according to claim 21, wherein: The mask includes a circular mask having a grid pattern.

24. The method according to claim 21, wherein: Opaque polymers include negative photoresists.

25. The method according to claim 20, wherein: The steps of setting up the lens element include: coating a thermoplastic polymer layer including a positive photoresist on the barrier layer; placing a mask having a pattern over portions of the thermoplastic polymer layer; exposing the thermoplastic polymer layer to ultraviolet light through a pattern of a mask; Dissolving the thermoplastic polymer layer exposed to ultraviolet light by a developer; applying a hydrophobic coating to the patterned thermoplastic polymer layer; The applied thermoplastic polymer layer is heated to form a spherical lens.

26. The method according to claim 25, wherein: The thermoplastic polymer layer comprises a transparent material that is formable by heating.

27. An image sensor comprising: a transparent substrate configured to refract light; a barrier layer comprising alternately stacked absorbing layers and transparent layers; an opening portion formed in the absorption layer and the transparent layer to transmit the light refracted by the transparent substrate to the lens element; a sensing element spaced apart from the lens element and configured to receive light collected by the lens element, The transparent substrate is arranged on a first side of the barrier layer, and the lens element is arranged on a second side of the barrier layer opposite to the first side.

28. The image sensor according to claim 27, wherein: The diameter of the opening gradually changes between two opposing surfaces of the barrier layer.

29. The image sensor according to claim 27, wherein: The opening portion includes a circular opening in each of the multiple absorption layers, and the degree to which the diameter of the circular opening formed in the multiple absorption layers increases from the absorption layer close to the lens element to the absorption layer away from the lens element is based on the field of view and the refractive index determined by the transparent layer and the transparent substrate arranged on the blocking layer.

30. The image sensor according to claim 27, further comprising: A spacer is located at an outer boundary of the barrier layer and the sensing element, wherein the spacer is configured to maintain a spacing between the barrier layer and the sensing element equal to a focal length of the lens element.

Images