Image sensor

Abstract

An image sensor comprises a sensing layer and a color filter layer, and the color filter layer is arranged on the sensing layer. The image sensor also includes a lens layer disposed on the color filter layer. The lens layer includes a plurality of microlenses. The image sensor also includes a first cut-off filter layer disposed over the lens layer. The first surface of the first cut-off filter layer is provided with a plurality of first protruding parts.

Description

Technical Field

[0001] The embodiments of the present invention relate to an image sensor, and more particularly to an image sensor having a cut-off filter layer. Background Art

[0002] Image sensors such as complementary metal oxide semiconductor (CMOS) image sensors (also called CIS (CMOS image sensor)) are widely used in various image acquisition devices such as digital still cameras, digital video cameras, and the like. The light sensing portion of the image sensor can detect environmental color changes, and can generate signal charges according to the amount of light received in the light sensing portion. In addition, the signal charges generated in the light sensing portion can be transmitted and amplified to obtain an image signal.

[0003] Based on industry demand, pixel size is continuously reduced. In order to maintain a high level of performance, a set of Phase Difference Auto Focus (PDAF) pixels can be integrated with traditional pixels. The light received by this set of PDAF pixels is converged through a color filter and collected to the bottom sensing part to detect the image focus of the device. Image sensors with minimized pixel size may experience slight accuracy deviations, which can significantly affect the overall performance of the device. Therefore, these and related issues need to be addressed through image sensor design and manufacturing.

[0004] Generally speaking, the conventional cut-off filter layer has a flat top surface, which may cause the total reflection of the cut-off filter layer to reflect the flare rays into the image sensor. Therefore, in order to maintain the level of product performance, the industry still needs to improve the cut-off filter layer to achieve the expected goal of maintaining the yield of the image sensor. Summary of the invention

[0005] An embodiment of the present invention provides an image sensor, comprising a sensing layer; a color filter layer disposed on the sensing layer; a lens layer disposed on the color filter layer, wherein the lens layer comprises a plurality of micro lenses; and a first cut-off filter layer disposed above the lens layer, wherein a first surface of the first cut-off filter layer has a plurality of first protrusions. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The embodiments of the present invention are best understood by the following detailed description in conjunction with the accompanying drawings. It should be noted that, in accordance with standard practice in the industry, various features are not drawn to scale and are for illustration purposes only. In fact, the sizes of various components may be arbitrarily enlarged or reduced to clearly illustrate the features of the embodiments of the present invention.

[0007] Figure 1 is a cross-sectional schematic diagram showing an image sensor according to some embodiments of the present disclosure.

[0008] Figure 2 , 3 as well as Figure 4 is a perspective schematic diagram showing a protrusion according to some embodiments of the present disclosure.

[0009] Figure 5 , 6 , 7, 8A, 8B, 8C, 9, 10, 11, 12 and Fig.13 is a cross-sectional schematic diagram showing an image sensor according to some embodiments of the present disclosure.

[0010] Fig.14 , 15 , 16 and Fig.17 is a perspective schematic diagram showing a protrusion according to some embodiments of the present disclosure.

[0011] Fig.18 is a cross-sectional schematic diagram showing an image sensor according to another embodiment of the present disclosure.

[0012] Description of reference numerals:

[0013] 10: Image sensor

[0014] 10a, 10b, 10c: Image sensor

[0015] 10d, 10e, 10f: Image sensor

[0016] 10g, 10h, 10i: Image sensor

[0017] 10j: Image sensor

[0018] 100: Sensing layer

[0019] 102: Light-shielding layer

[0020] 104: Sensor components

[0021] 105: Color filter layer

[0022] 110: Lens layer

[0023] 112: Micro lens

[0024] 115: First cut-off filter layer

[0025] 115a: First surface

[0026] 120: First protrusion

[0027] 121: Upper surface

[0028] 122: Surface

[0029] 125: Vertex

[0030] 125a: Vertex

[0031] 128: Sub-protrusion

[0032] 130: Second cut-off filter layer

[0033] 130a: Upper surface

[0034] 130b: Second surface

[0035] 135: Second protrusion

[0036] 140: Optical layer

[0037] 145: Adhesive layer

[0038] 150: Substrate

[0039] 155: Glass substrate

[0040] 160: Support structure

[0041] 165: Second protrusion

[0042] 170: Air

[0043] a: diameter

[0044] b: diameter

[0045] c: diameter

[0046] h: vertical distance

[0047] h c :high

[0048] k: coordinate

[0049] P: Pitch

[0050] P d : Pitch

[0051] P x : Pitch

[0052] P y : Pitch

[0053] X: First direction

[0054] Y: Second direction

[0055] Z: Third direction DETAILED DESCRIPTION

[0056] The following disclosure provides many embodiments or examples for implementing different elements of the subject matter provided. Specific examples of each element and its configuration are described below to simplify the description of the embodiments of the present invention. Of course, these are merely examples and are not intended to limit the embodiments of the present invention. For example, if the description mentions that a first element is formed on a second element, it may include an embodiment in which the first and second elements are in direct contact, and it may also include an embodiment in which an additional element is formed between the first and second elements so that they are not in direct contact. In addition, the embodiments of the present invention may repeat reference values ​​and / or letters in various examples. Such repetition is for the purpose of simplicity and clarity, rather than for indicating the relationship between the different embodiments and / or configurations discussed.

[0057] Furthermore, spatially relative terms such as "under," "below," "lower," "above," "upper," and the like may be used to facilitate description of the relationship between one component or feature and another component or feature in the drawings. Spatially relative terms are used to include different orientations of the device in use or operation, as well as the orientations depicted in the drawings. When the device is turned to a different orientation (rotated 90 degrees or other orientations), the spatially relative adjectives used therein will also be interpreted based on the orientation after the rotation.

[0058] Some embodiments of the present invention are described below. Additional steps may be provided before, during, and / or after the various stages described in these embodiments. Some of the stages described may be replaced or deleted in different embodiments. Additional components may be added to the semiconductor device structure. Some of the components described may be replaced or deleted in different embodiments. Although some of the embodiments discussed are performed in a specific order of steps, these steps may still be performed in another logical order.

[0059] As used herein, the term "about" means that the value of a given quantity may vary based on a particular technology node associated with the target semiconductor device. In some embodiments, based on a particular technology node, the term "about" may mean that the value of a given quantity is within a range of, for example, 10% to 30% of the value (e.g., ±10%, ±20%, or ±30% of the value).

[0060] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meanings as commonly understood by those skilled in the art to which the present invention belongs. It is understood that these terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with the background or context of the relevant technology and the present disclosure, and should not be interpreted in an idealized or overly formal manner unless specifically defined in the embodiments of the present disclosure.

[0061] In conventional configurations, an additional cut-off filter layer, such as an ultraviolet (UV) cut-off filter or an infrared (IR) cut-off filter, is usually added to the image sensor. The cut-off filter layer can block light of a specific wavelength and allow light of a selected wavelength to pass through, such as allowing light of a visible wavelength to pass through. However, the existing configuration of the cut-off filter layer is to integrate a cut-off filter layer with a flat top surface onto the image sensor. Since the blocking ability (or reflection ability) of the cut-off filter is still limited, and a flat cut-off filter layer may cause light to be repeatedly reflected between the cut-off filter layer and the image sensor and generate flare light into the image sensor, there is still a need to improve the design and configuration of the cut-off filter layer. By providing a cut-off filter layer with multiple protrusions, the embodiments of the present invention can effectively improve the problem of flare light and enhance the selectivity of the cut-off filter layer. In other words, the cut-off filter layer of the embodiments of the present invention can more effectively block (or reflect) light of a specific wavelength and reduce the percentage of light of the selected wavelength that is blocked (or reflected), thereby effectively improving the performance of the image sensor.

[0062] Figure 11 is a cross-sectional schematic diagram of an image sensor 10 according to some embodiments of the present disclosure. In some embodiments, the image sensor 10 includes a sensing layer 100, a color filter layer 105, and a lens layer 110. In some embodiments, the sensing layer 100 includes a light shielding layer 102 and a sensor element 104. In some embodiments, the sensing layer 100 may be formed on a substrate (not shown). In some embodiments, the substrate may be an elemental semiconductor including silicon or germanium; a compound semiconductor including gallium nitride (GaN), silicon carbide (SiC), gallium arsenide (GaAs), gallium phosphide (GaP), indium phosphide (InP), indium arsenide (InAs), and / or indium antimonide (InSb); an alloy semiconductor including silicon germanium (SiGe) alloy, gallium arsenide phosphide (GaAsP) alloy, aluminum indium arsenide (AlInAs) alloy, aluminum gallium arsenide (AlGaAs) alloy, gallium indium arsenide (GaInAs) alloy, gallium indium phosphide (GaInP) alloy, and / or gallium indium arsenide phosphide (GaInAsP) alloy; or a combination thereof. In some embodiments, the substrate may be a photoelectric conversion substrate, such as a silicon substrate or an organic photoelectric conversion layer. In other embodiments, the substrate may also be a semiconductor on insulator (SOI) substrate. The semiconductor on insulator substrate may include a substrate, a buried oxide layer disposed on the substrate, and a semiconductor layer disposed on the buried oxide layer. In addition, the conductivity type of the substrate may be N-type or P-type.

[0063] The light shielding layer 102 may define the area of ​​the sensor element 104. The sensor element 104 may include a sensing unit such as a photodiode, which may convert a received optical signal into an electrical signal. In some embodiments, the light shielding layer 102 may have a lower refractive index than the sensor element 104. The refractive index is a property of a substance that changes the speed of light, and is the ratio of the speed of light in a vacuum to the speed of light in a medium. When light propagates between two different materials at a certain angle, its refractive index determines the angle of light transmission (refraction). When incident light enters the sensing layer 100, the light shielding layer 102 may isolate the light within a specific unit to achieve the effect of light capture. In some embodiments, the material of the light shielding layer 102 may include a transparent dielectric material.

[0064] See also Figure 1, the color filter layer 105 is disposed on the sensing layer 100. In some embodiments, the height of the color filter layer 105 may range from about 0.3 μm to 2.0 μm. In a specific embodiment, the height of the color filter layer 105 may be about 0.9 μm. In some embodiments, the color filter layer 105 may include a plurality of units, and the color thereof may be red, green, blue, white, or infrared. In some embodiments, the color filter layer 105 may be formed sequentially by coating, exposing, and developing processes in different steps. Alternatively, the color filter layer 105 may be formed by inkjet printing.

[0065] Continue to see Figure 1 , the lens layer 110 is disposed on the color filter layer 105. The lens layer 110 includes a plurality of micro lenses 112. The micro lenses 112 can allow light to converge together for tracking and detection. In some embodiments, the function of the lens layer 110 is to converge the incident light into the sensing layer 100 through the color filter layer 105. In some embodiments, the material of the lens layer 110 can be a transparent material. For example, the material can include glass, epoxy resin, silicone, polyurethane, any other applicable material, or a combination of the above, but the present disclosure is not limited thereto. In some embodiments, the lens layer 110 can be formed by a photoresist reflow method, a hot embossing method, any other applicable method, or a combination of the above. In some embodiments, the step of forming the lens layer 110 can include a spin-on coating process, a photolithography process, an etching process, any other applicable process, or a combination of the above, but the present disclosure is not limited thereto.

[0066] Still see Figure 1, the image sensor 10 further includes a first cut-off filter layer 115 disposed above the lens layer 110. In some embodiments, the first surface 115a of the first cut-off filter layer 115 has a plurality of first protrusions 120. As described above, a flat cut-off filter may cause light to be repeatedly reflected between the cut-off filter and the image sensor, and generate flare light in the image sensor. Therefore, an embodiment of the present invention provides a cut-off filter layer having a plurality of protrusions. The protrusions have a refractive index gradient characteristic in spatial material density, which improves the transmittance of selected wavelengths and the reflectivity of unwanted wavelengths. In some embodiments, the refractive index of the lens layer 110 is greater than the refractive index of the first cut-off filter layer 115. In some embodiments, the material of the first protrusion 120 of the first cut-off filter layer 115 includes ZrO2, TiO2, Si3N4, SiO2, indium tin oxide (ITO), Si, amorphous silicon, polycrystalline silicon, III-V semiconductor compounds, or combinations thereof. In some embodiments, the material of the first protrusion 120 includes photoresist, acrylic, plastic, glass, glue, polydimethylsiloxane (PDMS), light-curing material, heat-curing material, or a combination thereof. In some embodiments, the first protrusion 120 is formed by a nanoimprinting process, an optical lithography process, a material reflow process, a molding process, a laser engraving process, an electron beam engraving process, or a combination thereof. In some embodiments, the first protrusion 120 is formed by light curing, heat curing, stress curing, electron curing, or a combination thereof.

[0067] See also Figure 2 . Figure 2 is a perspective schematic diagram showing the first protrusion 120 according to some embodiments of the present disclosure. In some embodiments, each first protrusion 120 satisfies the following formula (1) in the cross section in the first direction X and the second direction Y:

[0068] (xk) 2 =q(y-200r) (1)

[0069] Wherein x is the coordinate of each first protrusion 120 in the first direction X, y is the coordinate of each first protrusion 120 in the second direction Y, k is the coordinate of the vertex 125 of each first protrusion 120 in the first direction X, q is a constant less than 0, r is a constant greater than 1, and the first direction X is perpendicular to the second direction Y. In some embodiments, the larger q is, the larger the opening of the bottom surface of the first protrusion 120 in the cross section is. In some embodiments, the height h of each first protrusion 120 satisfies h=200r. That is, the larger r is, the larger h is. In some embodiments, the first protrusion 120 is a periodic structure, in other words, the entire structure has the same period and structural appearance. In some embodiments, the pitch P of two adjacent first protrusions 120 is less than about 700nm. The pitch P represents the distance between any two adjacent protrusions.

[0070] See also Figure 3 . Figure 3 is a perspective schematic diagram showing the first protrusion 120 according to other embodiments of the present disclosure. In some embodiments, each first protrusion 120 has a flat upper surface 121, and the diameter a of the flat upper surface 121 is smaller than the diameter b of the bottom surface of each first protrusion 120. In some embodiments, the curved surface 122 connecting the flat upper surface 121 and the bottom surface of each first protrusion 120 satisfies the following formula (2) in the cross section in the first direction X and the second direction Y:

[0071] y=q(xk) 2 +h (2)

[0072] Wherein x is the coordinate of each first protrusion 120 in the first direction X, y is the coordinate of each first protrusion 120 in the second direction Y, k is the coordinate of the vertex 125a of each first protrusion 120 in the first direction X, q is a constant less than 0, h is the vertical distance between the flat upper surface 121 and the bottom surface of each first protrusion 120, and the first direction X is perpendicular to the second direction Y.

[0073] See also Figure 4 . Figure 4According to other embodiments of the present disclosure, a perspective schematic diagram showing the first protrusion 120 is presented. In some embodiments, each first protrusion 120 has a flat upper surface 121, and the diameter a of the flat upper surface 121 is smaller than the diameter b of the bottom surface of each first protrusion 120. In addition, in some embodiments, each first protrusion 120 has a sub-protrusion 128 on the flat upper surface 121. In some embodiments, the sub-protrusion 128 on the flat upper surface 121 is a conical structure. In some embodiments, the curved surface 122 connecting the flat upper surface 121 and the bottom surface of each first protrusion 120 satisfies the following formula (2) in the cross-section of the first direction X and the second direction Y:

[0074] y = q(x - k) 2 + h(2)

[0075] where x is the coordinate of each first protrusion 120 in the first direction X, y is the coordinate of each first protrusion 120 in the second direction Y, k is the coordinate of the vertex 125a of the flat upper surface 121 of each first protrusion 120 in the first direction X, q is a constant less than 0, h is the vertical distance between the flat upper surface 121 and the bottom surface of each first protrusion 120, and the first direction X is perpendicular to the second direction Y. In some embodiments, the diameter c of the bottom surface of the sub-protrusion 128 on the flat upper surface 121 satisfies c ≤ a < b. In some embodiments, the height h of the sub-protrusion 128 c will satisfy h > h c .

[0076] Figure 5 According to some embodiments of the present disclosure, a cross-sectional schematic diagram showing the image sensor 10a is presented. In some embodiments, the first surface 115a of the first filter layer 115 is concave. In addition, in some embodiments, the image sensor 10a further includes a second cut-off filter layer 130, and the second cut-off filter layer 130 is disposed between the first cut-off filter layer 115 and the lens layer 110, that is, the second cut-off filter layer 130 is disposed on the lens layer 110 and the first cut-off filter layer 115 is disposed on the second cut-off filter layer 130. Using the second cut-off filter layer 130 with a lower refractive index allows the lens layer 110 to have a higher optical power. In some embodiments, the refractive index of the lens layer 110 is greater than the refractive index of the second cut-off filter layer 130. In some embodiments, the refractive index of the first cut-off filter layer 115 is greater than the refractive index of the second cut-off filter layer 130.

[0077] Figure 6 According to some embodiments of the present disclosure, a cross-sectional schematic diagram showing the image sensor 10b is presented. Figure 6 Approximates Figure 5 , but the difference is that the second cut-off filter layer 130 also has a plurality of protrusions. In some embodiments, the first surface 115a of the first filter layer 115 is a concave surface. In some embodiments, the image sensor 10b further includes a second cut-off filter layer 130 disposed between the first cut-off filter layer 115 and the lens layer 110. In some embodiments, the upper surface 130a of the second cut-off filter layer 130 has a plurality of second protrusions 135. The use of the second cut-off filter layer 130 having the second protrusions 135 and a lower refractive index allows the lens layer 110 to have a higher transparency and a higher optical magnification. In some embodiments, the refractive index of the lens layer 110 is greater than the refractive index of the second cut-off filter layer 130. In some embodiments, the refractive index of the first cut-off filter layer 115 is greater than the refractive index of the second cut-off filter layer 130.

[0078] Figure 7 is a cross-sectional schematic diagram showing an image sensor 10 c according to some embodiments of the present disclosure. Figure 7 Approximately Figure 5 , but the difference is that the second cut-off filter layer 130 has a concave surface. In some embodiments, the first surface 115a of the first filter layer 115 is a concave surface. In some embodiments, the image sensor 10c further includes a second cut-off filter layer 130 disposed between the first cut-off filter layer 115 and the lens layer 110. In some embodiments, the upper surface 130a of the second cut-off filter layer 130 has a plurality of second protrusions 135. In some embodiments, the upper surface 130a of the second filter layer 130 is a concave surface. Using the second cut-off filter layer 130 having the second protrusions 135 and the concave surface allows the image sensor 10c to adjust image distortion and reduce flare light from the image sensor 10c. In some embodiments, the refractive index of the lens layer 110 is greater than the refractive index of the second cut-off filter layer 130. In some embodiments, the refractive index of the first cut-off filter layer 115 is greater than the refractive index of the second cut-off filter layer 130.

[0079] Fig. 8A , 8B as well as Figure 8C FIG. 1 is a cross-sectional schematic diagram of an image sensor 10d according to some embodiments of the present disclosure. Fig. 8A As shown, the first surface 115a of the first cut-off filter layer 115 is concave. However, in other embodiments, such as Figure 8B as well as Figure 8C As shown, the first surface 115a of the first cut-off filter layer 115 may be a convex surface or a conical surface. In some embodiments, the first surface 115a of the first cut-off filter layer 115 satisfies the following formula (3) in the cross section in the first direction X and the second direction Y:

[0080]

[0081] Wherein x is the coordinate of each first protrusion 120 in the first direction X, y is the coordinate of each first protrusion 120 in the second direction Y, k is the cone constant, c is the curvature, a, b, d, e, f, g are constants, and the first direction X is perpendicular to the second direction Y. In some embodiments, the profile of the concave surface is an aspheric continuous surface.

[0082] Fig. 9 1 is a cross-sectional schematic diagram of an image sensor 10e according to some embodiments of the present disclosure. In some embodiments, the first surface 115a of the first cut-off filter layer 115 is a free-form surface. Fig. 9 As shown, the first surface 115a of the first filter layer 115 also satisfies formula (3) in the cross section along the first direction X and the second direction Y. By using a free-form surface, the image sensor 10e can have better image quality.

[0083] Fig.10 1 is a cross-sectional schematic diagram of an image sensor 10f according to some embodiments of the present disclosure. In some embodiments, the first surface 115a of the first cut-off filter layer 115 is a free-form surface. In some embodiments, the image sensor 10f further includes a second cut-off filter layer 130 and an optical layer 140, and the second cut-off filter layer 130 and the optical layer 140 are disposed between the first cut-off filter layer 115 and the lens layer 110. In some embodiments, the second cut-off filter layer 130 is disposed on the lens layer 110, and the optical layer 140 is disposed on the second cut-off filter layer 130 and in direct contact with the first cut-off filter layer 115. In some embodiments, the refractive index of the lens layer 110 is greater than the refractive index of the second cut-off filter layer 130. In some embodiments, the second cut-off filter layer 130 has a flat upper surface. Using the second cut-off filter layer 130 with a lower refractive index allows the lens layer 110 to have a higher optical magnification. In some embodiments, the optical layer 140 can be a multi-film for passing a specific wavelength. In some embodiments, the optical layer 140 may be a film layer having optical functions, such as an IR cut-off filter, a UV cut-off filter, a band pass filter, an anti-glare filter, or a combination thereof.

[0084] Fig.111 is a schematic cross-sectional view of an image sensor 10g according to some embodiments of the present disclosure. In some embodiments, the first surface 115a of the first cut-off filter layer 115 is a free-form surface. In some embodiments, the image sensor 10g further includes a glue layer 145 and a substrate 150. In some embodiments, the glue layer 145 is disposed on the lens layer 110, and the substrate 150 is fixed above the lens layer 110 through the glue layer 145 and is in direct contact with the first cut-off filter layer 115. In some embodiments, the glue layer 145 and the substrate 150 are disposed between the first cut-off filter layer 115 and the lens layer 110. The glue layer 145 is used to attach the substrate 150 to the lens layer 110. In some embodiments, the material of the substrate 150 may be photoresist, acrylic, plastic, glass, or a high-transmittance material. In some embodiments, the substrate 150 may be packaged on the image sensor 10g to increase the reliability of the image sensor 10g.

[0085] Fig.12 1 is a cross-sectional schematic diagram of an image sensor 10h according to some embodiments of the present disclosure. In some embodiments, the first surface 115a of the first cut-off filter layer 115 is a free-form surface. In some embodiments, the image sensor 10h further includes a second cut-off filter layer 130, a glue layer 145, and a substrate 150. In some embodiments, the second cut-off filter layer 130 is disposed on the lens layer 110. In some embodiments, the refractive index of the lens layer 110 is greater than the refractive index of the second cut-off filter layer 130. In some embodiments, the second cut-off filter layer 130 has a flat upper surface. In some embodiments, the glue layer 145 is disposed on the second cut-off filter layer 130. In some embodiments, the substrate 150 fixes the second cut-off filter layer 130 on the second cut-off filter layer 130 through the glue layer 145 and is in direct contact with the first cut-off filter layer 115. In some embodiments, the second cut-off filter layer 130, the glue layer 145, and the substrate 150 are disposed between the first cut-off filter layer 115 and the lens layer 110.

[0086] Fig.131 is a cross-sectional schematic diagram of an image sensor 10i according to some embodiments of the present disclosure. In some embodiments, the first surface 115a of the first cut-off filter layer 115 is a free-form surface. In some embodiments, the image sensor 10i further includes a second cut-off filter layer 130, an optical layer 140, a glue layer 145, and a substrate 150. In some embodiments, the second cut-off filter layer 130 is disposed on the lens layer 110. In some embodiments, the refractive index of the lens layer 110 is greater than the refractive index of the second cut-off filter layer 130. In some embodiments, the refractive index of the lens layer 110 is greater than the refractive index of the second cut-off filter layer 130. In some embodiments, the second cut-off filter layer 130 has a flat upper surface. In some embodiments, the optical layer 140 is disposed on the second cut-off filter layer 130. In some embodiments, the glue layer 145 is disposed on the optical layer 140. In some embodiments, the substrate 150 is fixed above the optical layer 140 through the glue layer 145 and is in direct contact with the first cut-off filter layer 115. In some embodiments, the second cut-off filter layer 130 , the optical layer 140 , the adhesive layer 145 , and the substrate 150 are disposed between the first cut-off filter layer 115 and the lens layer 110 .

[0087] The arrangement of the first protrusions 120 affects the quality of the optical performance. The denser the arrangement, the better the performance. The first protrusions 120 can be arranged in a square, an offset square, a regular hexagon, or a random arrangement. For example, Fig.14 1 is a perspective schematic diagram showing the first protrusion 120 according to some embodiments of the present disclosure. In some embodiments, the first protrusion 120 is, for example, Figure 1 , Figure 5 ,or FIG. 8A to FIG. 8C The position in the first direction X can be projected onto the sensing layer 100. In some embodiments, after the position of the first protrusion 120 is projected onto the sensing layer 100, the pitch P of two adjacent first protrusions 120 in the first direction X is x is equal to the pitch P of two adjacent first protrusions 120 in the second direction Y y .

[0088] Fig.15 1 is a perspective schematic diagram showing the first protrusion 120 according to some embodiments of the present disclosure. In some embodiments, the first protrusion 120 is, for example, Figure 1 , Figure 5 ,or FIG. 8A to FIG. 8C The position in the first direction X can be projected onto the sensing layer 100. In some embodiments, after the position of the first protrusion 120 is projected onto the sensing layer 100, the pitch P of two adjacent first protrusions 120 in the first direction X is x is equal to the pitch P of two adjacent first protrusions 120 in the second direction Y y half.

[0089] Fig.16 1 is a perspective schematic diagram showing the first protrusion 120 according to some embodiments of the present disclosure. In some embodiments, the first protrusion 120 is, for example, Figure 1 , Figure 5 ,or FIG. 8A to FIG. 8C The position in the image may be projected onto the sensing layer 100. In some embodiments, after the position of the first protrusions 120 is projected onto the sensing layer 100, any two first protrusions have the same pitch P. d .

[0090] Fig.17 1 is a perspective schematic diagram showing the first protrusion 120 according to some embodiments of the present disclosure. In some embodiments, the first protrusion 120 is, for example, Figure 1 , Figure 5 ,or FIG. 8A to FIG. 8C The positions in the image may be projected onto the sensing layer 100. In some embodiments, after the positions of the first protrusions 120 are projected onto the sensing layer 100, the first protrusions 120 are randomly arranged.

[0091] Fig.18 1 is a cross-sectional schematic diagram of an image sensor 10j according to some embodiments of the present disclosure. In some embodiments, the first surface 115a of the first cut-off filter layer 115 is a free-form surface. In some embodiments, the image sensor 10j further includes a second cut-off filter layer 130, a glass substrate 155, and a support structure 160. In some embodiments, the second cut-off filter layer 130 is disposed above the lens layer 110 and below the first cut-off filter layer 115. In some embodiments, the second surface 130b of the second cut-off filter layer 130 has a plurality of second protrusions 165. In some embodiments, the glass substrate 155 is disposed between the first cut-off filter layer 115 and the second cut-off filter layer 130 and fixes the first cut-off filter layer 115 and the second cut-off filter layer 130. In some embodiments, the support structure 160 separates the lens layer 110 from the first cut-off filter layer 115, the glass substrate 155, and the second cut-off filter layer 130, so that the second cut-off filter layer 130 is separated from the lens layer 110 by air 170. In other words, the film layer with a low refractive index is replaced by air 170 .

[0092] In summary, the embodiments of the present invention provide a cut-off filter layer having a plurality of protrusions, which can effectively improve the flare light problem and enhance the selectivity of the cut-off filter layer. In other words, the cut-off filter layer of the embodiments of the present invention can more effectively block (or reflect) light of a specific wavelength and reduce the percentage of light of the selected wavelength that is blocked (or reflected), which effectively improves the performance of the image sensor. Therefore, the various embodiments described in the present disclosure provide multiple advantages over the prior art. It should be understood that not all advantages are necessarily discussed here, not all embodiments need to have specific advantages, and other embodiments may provide different advantages.

[0093] An embodiment of the present invention provides an image sensor, which includes a sensing layer; a color filter layer disposed on the sensing layer; a lens layer disposed on the color filter layer, wherein the lens layer includes a plurality of micro lenses; and a first cut-off filter layer disposed above the lens layer, wherein a first surface of the first cut-off filter layer has a plurality of first protrusions.

[0094] In some embodiments, each first protrusion satisfies the following formula (1) in the cross-sections in the first direction and the second direction:

[0095] (xk) 2 =q(y-200r)(1)

[0096] Wherein x is the coordinate of each first protrusion in the first direction, y is the coordinate of each first protrusion in the second direction, k is the coordinate of the vertex of each first protrusion in the first direction, q is a constant less than 0, r is a constant greater than 1, and the first direction is perpendicular to the second direction.

[0097] In some embodiments, the height h of each first protrusion satisfies h=200r. In some embodiments, the pitch between two adjacent first protrusions is less than about 700 nanometers, and each first protrusion has a flat upper surface, and the diameter a of the flat upper surface is smaller than the diameter b of the bottom surface of each first protrusion.

[0098] In some embodiments, the curved surface connecting the flat upper surface and the bottom surface of each first protrusion satisfies the following formula (2) in the cross section in the first direction and the second direction:

[0099] y=q(xk) 2 +h(2)

[0100] Wherein x is the coordinate of each first protrusion in the first direction, y is the coordinate of each first protrusion in the second direction, k is the coordinate of the vertex of each first protrusion in the first direction, q is a constant less than 0, h is the vertical distance between the flat upper surface and the bottom surface of each first protrusion, and the first direction is perpendicular to the second direction.

[0101] In some embodiments, each of the first protrusions has sub-protrusions on the flat upper surface, and the sub-protrusions are conical structures, and the diameter c of the bottom surface of the sub-protrusions satisfies c ≤ a < b, and the height h of the sub-protrusions c satisfies h > h c . In some embodiments, the first surface of the first cut-off filter layer is a concave surface, a convex surface, a conical surface, or a free-form surface. In some embodiments, the image sensor further includes a second cut-off filter layer disposed between the first cut-off filter layer and the lens layer, the refractive index of the lens layer is greater than that of the second cut-off filter layer, and the refractive index of the first cut-off filter layer is greater than that of the second cut-off filter layer, and the upper surface of the second cut-off filter layer has a plurality of second protrusions.

[0102] In some embodiments, the first surface of the first cut-off filter layer satisfies the following formula (3) in the cross-section in the first direction and the second direction:

[0103]

[0104] where x is the coordinate of the first surface in the first direction, y is the coordinate of the first surface in the second direction, k is the conic constant, c is the curvature, and a, b, d, e, f, g are constants, and the first direction is perpendicular to the second direction.

[0105] In some embodiments, the image sensor further includes a second cut-off filter layer disposed on the lens layer, the refractive index of the lens layer is greater than that of the second cut-off filter layer, and the second cut-off filter layer has a flat upper surface; and an optical layer disposed on the second cut-off filter layer and in direct contact with the first cut-off filter layer, and the second cut-off filter layer and the optical layer are disposed between the first cut-off filter layer and the lens layer. In some embodiments, the image sensor further includes an adhesive layer disposed on the lens layer; and a substrate fixed above the lens layer through the adhesive layer and in direct contact with the first cut-off filter layer, and the adhesive layer and the substrate are disposed between the first cut-off filter layer and the lens layer.

[0106] In some embodiments, the image sensor further comprises a second cut-off filter layer disposed on the lens layer, wherein the refractive index of the lens layer is greater than the refractive index of the second cut-off filter layer, and the second cut-off filter layer has a flat upper surface; a glue layer disposed on the second cut-off filter layer; and a substrate fixed on the second cut-off filter layer through the glue layer and in direct contact with the first cut-off filter layer, and the second cut-off filter layer, the glue layer, and the substrate are disposed between the first cut-off filter layer and the lens layer. In some embodiments, the image sensor further comprises a second cut-off filter layer disposed on the lens layer, wherein the refractive index of the lens layer is greater than the refractive index of the second cut-off filter layer, and the second cut-off filter layer has a flat upper surface; an optical layer disposed on the second cut-off filter layer; a glue layer disposed on the optical layer; and a substrate fixed on the optical layer through the glue layer and in direct contact with the first cut-off filter layer, and the second cut-off filter layer, the optical layer, the glue layer, and the substrate are disposed between the first cut-off filter layer and the lens layer.

[0107] In some embodiments, after the position of the first protrusion is projected onto the sensing layer, the pitch of two adjacent first protrusions in the first direction is equal to the pitch of two adjacent first protrusions in the second direction. In some embodiments, after the position of the first protrusion is projected onto the sensing layer, the pitch of two adjacent first protrusions in the first direction is equal to half of the pitch of two adjacent first protrusions in the second direction. In some embodiments, after the position of the first protrusion is projected onto the sensing layer, any two of the first protrusions have the same pitch. In some embodiments, after the position of the first protrusion is projected onto the sensing layer, the first protrusions are randomly arranged.

[0108] In some embodiments, the material of the first protrusion of the first cut-off filter layer includes: ZrO2, TiO2, Si3N4, SiO2, indium tin oxide (ITO), Si, amorphous silicon, polycrystalline silicon, III-V semiconductor compounds, or a combination thereof, or wherein the material of the first protrusions of the first cut-off filter layer includes: photoresist, acrylic, plastic, glass, glue, polydimethylsiloxane (PDMS), photocurable material, thermal curable material, or a combination thereof. In some embodiments, the first protrusion is formed by a nanoimprint process, an optical lithography process, a material reflow process, a molding process, a laser engraving process, an electron beam engraving process, or a combination thereof, or in some embodiments, the first protrusion is formed by photocuring, thermal curing, stress curing, electronic curing, or a combination thereof.

[0109] In some embodiments, the image sensor further includes a second cutoff filter layer, which is disposed above the lens layer and below the first cutoff filter layer, and the second surface of the second cutoff filter layer has a plurality of second protrusions; a glass substrate, which is disposed between the first cutoff filter layer and the second cutoff filter layer and fixes the first cutoff filter layer and the second cutoff filter layer; and a supporting structure, which separates the lens layer from the first cutoff filter layer, the glass substrate, and the second cutoff filter layer, so that the second cutoff filter layer and the lens layer are separated by air.

[0110] The scope of the present invention is not limited to the technical solutions formed by a specific combination of the above-mentioned technical features, but should also cover other technical solutions formed by any combination of the above-mentioned technical features or their equivalent features.

[0111] The above embodiments can be arbitrarily combined to form new embodiments, and all new embodiments formed by such combinations are within the protection scope of the present invention.

[0112] The features of several embodiments are summarized above so that those skilled in the art to which the present invention belongs can better understand the viewpoints of the embodiments of the present invention. Those skilled in the art to which the present invention belongs should understand that other processes and structures can be easily designed or modified based on the embodiments of the present invention to achieve the same purposes and / or advantages as the embodiments introduced herein. Those skilled in the art to which the present invention belongs should also understand that such equivalent structures do not deviate from the concept and scope of the present invention, and various changes, substitutions, and replacements can be made without violating the concept and scope of the present invention. Therefore, the scope of protection of the present invention shall be defined as defined by the claims.

[0113] References throughout this specification to features, advantages, or similar language do not imply that all features and advantages that may be realized using the present disclosure should or may be realized in any single embodiment of the present disclosure. Conversely, language referring to features and advantages is understood to mean that a particular feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present disclosure. Thus, discussions of features and advantages and similar language throughout this specification may, but do not necessarily, represent the same embodiment.

[0114] Furthermore, in one or more embodiments, the described features, advantages, and characteristics of the present disclosure may be combined in any suitable manner. Based on the description herein, those skilled in the relevant art will appreciate that the present disclosure may be implemented without one or more specific features or advantages of a particular embodiment. In other cases, additional features and advantages may be identified in certain embodiments that may not be present in all embodiments of the present disclosure.

Claims

1. An image sensor, comprising: a sensing layer; a color filter layer, disposed on the sensing layer; a lens layer disposed on the color filter layer, wherein the lens layer includes a plurality of micro lenses; and A first cut-off filter layer is disposed above the lens layer, wherein a first surface of the first cut-off filter layer has a plurality of first protrusions.

2. The image sensor as claimed in claim 1, wherein each of the first protrusions satisfies the following formula (1) in a cross section in a first direction and a second direction: (x-k) 2 =q(y-200r) (1) Wherein x is the coordinate of each of the first protrusions in the first direction, y is the coordinate of each of the first protrusions in the second direction, k is the coordinate of a vertex of each of the first protrusions in the first direction, q is a constant less than 0, r is a constant greater than 1, and the first direction is perpendicular to the second direction, and wherein the height h of each of the first protrusions satisfies h=200r.

3. The image sensor as claimed in claim 1, wherein a pitch between two adjacent first protrusions is less than about 700 nanometers, and wherein each of the first protrusions has a flat upper surface, and a diameter a of the flat upper surface is smaller than a diameter b of a bottom surface of each of the first protrusions.

4. The image sensor as claimed in claim 3, wherein a curved surface connecting the flat upper surface and the bottom surface of each of the first protrusions satisfies the following formula (2) in a cross section in a first direction and a second direction: y=q(x-k) 2 +h (2) Wherein x is the coordinate of each of the first protrusions in the first direction, y is the coordinate of each of the first protrusions in the second direction, k is the coordinate of a vertex of each of the first protrusions in the first direction, q is a constant less than 0, h is the vertical distance between the flat upper surface and the bottom surface of each of the first protrusions, and the first direction is perpendicular to the second direction.

5. The image sensor according to claim 4, wherein each of the first protrusions has a sub-protrusion on the flat upper surface, and wherein the sub-protrusion is a conical structure, and wherein the diameter c of a bottom surface of the sub-protrusion satisfies c ≤ a < b, and wherein the height h of the sub-protrusion c satisfies h > h c .

6. The image sensor as claimed in claim 1, wherein the first surface of the first cut-off filter layer is a concave surface, a convex surface, a conical surface, or a free-form surface, wherein the first protrusions are formed by a nano-imprinting process, an optical photolithography process, a material reflow process, a molding process, a laser engraving process, an electron beam engraving process, or a combination thereof, or wherein the first protrusions are formed by photocuring, thermal curing, stress curing, electronic curing, or a combination thereof.

7. The image sensor of claim 6, further comprising: A second cut-off filter layer is disposed between the first cut-off filter layer and the lens layer, wherein the refractive index of the lens layer is greater than the refractive index of the second cut-off filter layer, wherein the refractive index of the first cut-off filter layer is greater than the refractive index of the second cut-off filter layer, and wherein an upper surface of the second cut-off filter layer has a plurality of second protrusions.

8. The image sensor as claimed in claim 6, wherein the first surface of the first cut-off filter layer satisfies the following formula (3) in cross-sections in a first direction and a second direction: Wherein x is the coordinate of the first surface in the first direction, y is the coordinate of the first surface in the second direction, k is the cone constant, c is the curvature, a, b, d, e, f, g are constants, and the first direction is perpendicular to the second direction.

9. The image sensor of claim 6, further comprising: a second cut-off filter layer disposed on the lens layer, wherein the refractive index of the lens layer is greater than the refractive index of the second cut-off filter layer, wherein the second cut-off filter layer has a flat upper surface; as well as An optical layer is disposed on the second cut-off filter layer and directly contacts the first cut-off filter layer, wherein the second cut-off filter layer and the optical layer are disposed between the first cut-off filter layer and the lens layer.

10. The image sensor of claim 6, further comprising: an adhesive layer disposed on the lens layer; as well as A substrate is fixed on the lens layer through the adhesive layer and is in direct contact with the first cut-off filter layer, wherein the adhesive layer and the substrate are arranged between the first cut-off filter layer and the lens layer.

11. The image sensor of claim 6, further comprising: a second cut-off filter layer disposed on the lens layer, wherein the refractive index of the lens layer is greater than the refractive index of the second cut-off filter layer, wherein the second cut-off filter layer has a flat upper surface; a glue layer, disposed on the second cut-off filter layer; as well as A substrate is fixed on the second cut-off filter layer through the adhesive layer and is in direct contact with the first cut-off filter layer, wherein the second cut-off filter layer, the adhesive layer, and the substrate are disposed between the first cut-off filter layer and the lens layer.

12. The image sensor of claim 6, further comprising: a second cut-off filter layer disposed on the lens layer, wherein the refractive index of the lens layer is greater than the refractive index of the second cut-off filter layer, wherein the second cut-off filter layer has a flat upper surface; an optical layer, disposed on the second cut-off filter layer; an adhesive layer disposed on the optical layer; as well as A substrate is fixed on the optical layer through the adhesive layer and is in direct contact with the first cut-off filter layer, wherein the second cut-off filter layer, the optical layer, the adhesive layer, and the substrate are disposed between the first cut-off filter layer and the lens layer.

13. The image sensor as claimed in claim 1, wherein after the positions of the first protrusions are projected onto the sensing layer, a pitch between two adjacent first protrusions in a first direction is equal to a pitch between two adjacent first protrusions in a second direction, or a pitch between two adjacent first protrusions in the first direction is equal to half of a pitch between two adjacent first protrusions in the second direction.

14. The image sensor as claimed in claim 1, wherein the material of the first protrusions of the first cut-off filter layer comprises: ZrO2, TiO2, Si3N4, SiO2, indium tin oxide, Si, amorphous silicon, polycrystalline silicon, III-V semiconductor compounds, or a combination thereof, or the material of the first protrusions of the first cut-off filter layer includes: photoresist, acrylic, plastic, glass, glue, polydimethylsiloxane, photocurable material, thermosetting material, or a combination thereof.

15. The image sensor of claim 1, further comprising: a second cut-off filter layer, disposed above the lens layer and below the first cut-off filter layer, wherein a second surface of the second cut-off filter layer has a plurality of second protrusions; a glass substrate disposed between the first cut-off filter layer and the second cut-off filter layer and fixing the first cut-off filter layer and the second cut-off filter layer; as well as A supporting structure is used to separate the lens layer from the first cut-off filter layer, the glass substrate, and the second cut-off filter layer, so that the second cut-off filter layer and the lens layer are separated by air.

Images