SOLID-STATE IMAGE SENSOR

A solid-state image sensor is provided. The solid-state image sensor includes photoelectric conversion elements and a color filter layer disposed above the photoelectric conversion elements. The color filter layer has a first color filter segment and a second color filter segment adjacent to the first color filter segment. The first color filter segment and the second color filter segment correspond to different colors. The solid-state image sensor further includes a light-splitting structure disposed in the first color filter segment or the second color filter segment and a grid structure disposed between the first color filter segment and the second color filter segment. The light-splitting structure is separated from the grid structure.

BACKGROUND

Technical Field

The embodiments of the present disclosure relate to image sensors, and in particular they relate to solid-state image sensors that include a light-splitting structure disposed in the color filter layer.

Description of the Related Art

Solid-state image sensors (e.g., charge-coupled device (CCD) image sensors, complementary metal-oxide semiconductor (CMOS) image sensors, and so on) have been widely used in various image-capturing apparatuses such as digital still-image cameras, digital video cameras, and the like. The light-sensing portion in the solid-state image sensor may be formed at each of pixels, and signal electric charges may be generated according to the amount of light received in the light-sensing portion. In addition, the signal electric charges generated in the light-sensing portion may be transmitted and amplified, whereby an image signal is obtained.

In traditional multi-PD (i.e., one micro lens corresponds to two, four, or more photo diodes) solid-state image sensor, after light with long wavelength enters the solid-state image sensor, it may be focused on the isolation structure (e.g., deep trench isolations (DTI)), which may cause strong scattering and generate crosstalk. Therefore, there are still various challenges in the design and manufacturing of solid-state image sensors.

BRIEF SUMMARY

In some embodiments of the present disclosure, the solid-state image sensor includes a light-splitting structure disposed in (the color filter segment of) the color filter layer, which may effectively reduce scattering and crosstalk, thereby improving the quality of the image signal from the photoelectric conversion elements of the solid-state image sensors.

In accordance with some embodiments of the present disclosure, a solid-state image sensor is provided. The solid-state image sensor includes photoelectric conversion elements and a color filter layer disposed above the photoelectric conversion elements. The color filter layer has a first color filter segment and a second color filter segment adjacent to the first color filter segment. The first color filter segment and the second color filter segment correspond to different colors. The solid-state image sensor further includes a light-splitting structure disposed in the first color filter segment or the second color filter segment and a grid structure disposed between the first color filter segment and the second color filter segment. The light-splitting structure is separated from the grid structure.

In some embodiments, the photoelectric conversion elements are divided into first photoelectric conversion elements and second photoelectric conversion elements. Each the first color filter segment corresponds to the first photoelectric conversion elements, and each second color filter segment corresponds to the second photoelectric conversion elements.

In some embodiments, the solid-state image sensor includes an isolation structure disposed between the photoelectric conversion elements and having first isolation segments and second isolation segments. The first isolation segments are disposed between the first photoelectric conversion elements and the second photoelectric conversion elements, and the second isolation segments are disposed between the first photoelectric conversion elements and between the second photoelectric conversion elements. The grid structure corresponds to the first isolation segments, and the light-splitting structure corresponds to at least one second isolation segment.

In some embodiments, from the top view of the solid-state image sensor, the light-splitting structure overlaps the corresponding second isolation segment.

In some embodiments, from the top view of the solid-state image sensor, when the profile of the light-splitting structure is cross-shaped, the light-splitting structure is offset from the corresponding second isolation segment by 0-45 degrees.

In some embodiments, the grid structure has a first shift with respect to the first isolation segments, and the light-splitting structure has a second shift with respect to the corresponding second isolation segment.

In some embodiments, the first shift is different from the second shift.

In some embodiments, the height of the light-splitting structure is equal to or less than the height of the grid structure.

In some embodiments, from the top view of the solid-state image sensor, the profile of the light-splitting structure is circular, square, rectangular or cross-shaped.

In some embodiments, the width of the light-splitting structure is between 50 nm and 200 nm.

In some embodiments, the ratio of the height of the light-splitting structure to the height of the color filter layer is between 0.3 and 0.9.

In some embodiments, the refractive index of the light-splitting structure is between 1 and 1.45.

In some embodiments, the light-splitting structure has a first portion disposed on the center of the first color filter segment or the second color filter segment and a second portion disposed near at least one corner of the first color filter segment or the second color filter segment.

In some embodiments, the light-splitting structure corresponds to two photoelectric conversion elements or four photoelectric conversion elements.

In some embodiments, the solid-state image sensor includes an inner pillar disposed on the bottom of the light-splitting structure. The inner pillar includes nontransparent material.

In some embodiments, the width of the inner pillar is between 50 nm and 100 nm, and the height of the inner pillar is less than 150 nm.

In some embodiments, the solid-state image sensor further includes an auxiliary light-splitting structure disposed on a bottom of the light-splitting structure.

In some embodiments, the auxiliary light-splitting structure is further disposed on a bottom of the grid structure.

In some embodiments, the auxiliary light-splitting structure includes at least one material that is different from the light-splitting structure, and the refractive index of the auxiliary light-splitting structure is between 1 and 1.65.

In some embodiments, the width of the auxiliary light-splitting structure is equal to or greater than the width of the light-splitting structure, and the height of the auxiliary light-splitting structure is between 50 nm and 350 nm.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, or examples, for implementing different features of the subject matter provided. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, a first feature is formed on a second feature in the description that follows may include embodiments in which the first feature and second feature are formed in direct contact, and may also include embodiments in which additional features may be formed between the first feature and second feature, so that the first feature and second feature may not be in direct contact.

It should be understood that additional steps may be implemented before, during, or after the illustrated methods, and some steps might be replaced or omitted in other embodiments of the illustrated methods.

In the present disclosure, the terms “about,” “approximately” and “substantially” typically mean +/-20% of the stated value, more typically +/-10% of the stated value, more typically +/-5% of the stated value, more typically +/-3% of the stated value, more typically +/-2% of the stated value, more typically +/-1% of the stated value and even more typically +/-0.5% of the stated value. The stated value of the present disclosure is an approximate value. That is, when there is no specific description of the terms “about,” “approximately” and “substantially”, the stated value includes the meaning of “about,” “approximately” or “substantially”.

The present disclosure may repeat reference numerals and/or letters in following embodiments. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

FIG.1is a top view illustrating a portion of the solid-state image sensor100in accordance with some embodiments of the present disclosure.FIG.2is a cross-sectional view CS1that may illustrate a portion of the solid-state image sensor100in accordance with some embodiments of the present disclosure. For example,FIG.2may be a cross-sectional view of a portion of the solid-state image sensor100along line A-A′ inFIG.1. It should be noted that some components of the solid-state image sensor100have been omitted inFIG.1andFIG.2for the sake of brevity.

Referring toFIG.2, in some embodiments, the solid-state image sensor100includes a semiconductor substrate10. The semiconductor substrate10may be a wafer or a chip. For example, the semiconductor substrate10may include silicon, but the present disclosure is not limited thereto.

In some embodiments, the semiconductor substrate10has a plurality of photoelectric conversion elements11, such as photoelectric conversion elements11B and photoelectric conversion elements11R as shown inFIG.2. The photoelectric conversion elements11are used for receiving different color lights. For example, the photoelectric conversion elements11B may be used for receiving blue light, and the photoelectric conversion elements11R may be used for receiving red light, but the present disclosure is not limited thereto. The semiconductor substrate10may have other photoelectric conversion elements that may be used for receiving, for example, green, yellow, white, cyan light, or IR/NIR, which may be adjusted depending on actual needs.

As shown inFIG.2, in some embodiments, the solid-state image sensor100includes an isolation structure13disposed between the photoelectric conversion elements11. For example, the isolation structure13may include a shallow trench isolation (STI) or a deep trench isolations (DTI). The isolation structure13may be formed in the semiconductor substrate10using etching process to form trenches and filling the trenches with an insulating or dielectric material, but the present disclosure is not limited thereto.

As shown in the cross-sectional view CS1ofFIG.2, in some embodiments, the isolation structure13has (or is divided into) first isolation segments13S1and second isolation segments13S2, the first isolation segments13S1are disposed between the photoelectric conversion elements11B and the photoelectric conversion elements11R, and the second isolation segments13S2are disposed between the photoelectric conversion elements11B and between the photoelectric conversion elements11R. In other words, the first isolation segments13S1may be used to separate the photoelectric conversion elements11that receive different color lights, and the second isolation segments13S2may be used to separate the photoelectric conversion elements11that receive the same color light. It should be noted that the first isolation segments13S1and the second isolation segments13S2are illustrated as dashed lines in the top view ofFIG.1.

Referring toFIG.1andFIG.2, in some embodiments, the solid-state image sensor100includes a color filter layer20disposed above the photoelectric conversion elements11(the semiconductor substrate10). In some embodiments, the color filter layer20has (or is divided into) color filter segments that correspond to the photoelectric conversion elements11. For example, as shown inFIG.2, the color filter layer20may have a blue color filter segment20SB that corresponds to the photoelectric conversion elements11B, and a red color filter segment20SR that corresponds to the photoelectric conversion elements11R. Moreover, as shown inFIG.1, the color filter layer20may have a green color filter segment20SG (there are two green color filter segments20SG shown inFIG.1) that corresponds to other photoelectric conversion elements, but the present disclosure is not limited thereto.

In some other embodiments, the color filter layer20has (or is divided into) other color filter segments. For example, the color filter layer20may have a yellow color filter segment, a white color filter segment, a cyan color filter segment, a magenta color filter segment, or an IR/NIR color filter, but the present disclosure is not limited thereto.

As shown inFIG.1andFIG.2, in some embodiments, the solid-state image sensor100includes a grid structure30disposed between the color filter segments. For example, as shown inFIG.1(andFIG.2), the grid structure30may be disposed between the green color filter segment20SG and the red color filter segment20SR, and between the green color filter segment20SG and the blue color filter segment20SB, but the present disclosure is not limited thereto. The grid structure30may include a transparent dielectric material that has a low refractive index in the range from about 1.0 to about 1.99. In some embodiments, the refractive index of the grid structure30is lower than the refractive index of the color filter layer20(that includes red color filter segment20SR, green color filter segment20SG, blue color filter segment20SB, and so on).

The grid structure30may be formed by depositing a dielectric layer on the semiconductor substrate10and then patterning the dielectric layer using photolithography and etching processes, but the present disclosure is not limited thereto. As shown inFIG.2, in some embodiments, the grid structure30corresponds to the first isolation segments13S1. For example, the central axis C30of the grid structure30may overlap the central axis C13S1of the first isolation segments13S1as shown inFIG.2. Moreover, the grid structure30may be aligned with the first isolation segments13S1, but the present disclosure is not limited thereto.

Referring toFIG.1andFIG.2, in some embodiments, the solid-state image sensor100includes a light-splitting structure40disposed in at least one color filter segment. For example, as shown inFIG.1andFIG.2, the light-splitting structures40may be disposed in the red color filter segment20SR, the green color filter segment20SG, and the blue color filter segment20SB, but the present disclosure is not limited thereto.

The material and the manufacturing method of the light-splitting structure40may be the same or similar to those of the grid structure30. In other words, the light-splitting structure40may include a transparent dielectric material, but the present disclosure is not limited thereto. In some embodiments, the refractive index of the light-splitting structure40is between about 1 and about 1.45.

As shown inFIG.1andFIG.2, in some embodiments, the light-splitting structure40is separated from the grid structure30. Moreover, in some embodiments, the light-splitting structure40corresponds to at least one second isolation segment13S2. For example, the central axis C40of the light-splitting structure40may overlap the central axis C13S2of the corresponding second isolation segment13S2as shown inFIG.2, but the present disclosure is not limited thereto.

In some embodiments, from the top view of the solid-state image sensor100(e.g.,FIG.1), the profile of the light-splitting structure40is square, but the present disclosure is not limited thereto. In some other embodiments, the profile of the light-splitting structure40is circular, rectangular, cross-shaped, or any other suitable shape. Moreover, in some embodiments, the width W40 of the light-splitting structure40is between about 50 nm and about 200 nm. Here, the width W40 of the light-splitting structure40is defined as the shortest distance of two parallel sides of the light-splitting structure40. Take the solid-state image sensor100(which is shown inFIG.1) as an example, the width W40 of the light-splitting structure40is defined as the side length of the square.

As shown inFIG.2, in some embodiments, the height H20 of the color filter layer20is equal to the height H30 of the grid structure30. Moreover, in some embodiments, the height H40 of the light-splitting structure40is lower than the height H20 of the color filter layer20. In some embodiments, the ratio of the height H40 of the light-splitting structure40to the height H20 of the color filter layer20(i.e., H40/H20) is between about 0.3 and about 0.9.

In the embodiments of the present disclosure, the light-splitting structure40disposed in (the color filter segment of) the color filter layer20may effectively reduce scattering and crosstalk, thereby improving the quality of the image signal from the photoelectric conversion elements11of the solid-state image sensor100. If the ratio of the height H40 of the light-splitting structure40to the height H20 of the color filter layer20(i.e., H40/H20) is less than 0.3, then the light-splitting structure40may not reduce scattering and crosstalk; if the ratio of the height H40 of the light-splitting structure40to the height H20 of the color filter layer20(i.e., H40/H20) is greater than 0.9, then crosstalk may occur in the color filter layer20.

In the embodiment shown inFIG.1, the light-splitting structure40is disposed in every color filter segment (e.g., red color filter segment20SR, green color filter segment20SG, and blue color filter segment20SB), but the present disclosure is not limited thereto. In some other embodiments, the light-splitting structure40is disposed merely in the specific color filter segment (e.g., green color filter segment20SG). As shown inFIG.1, each splitting structure40corresponds to four photoelectric conversion elements11, and the four photoelectric conversion elements11form a 2×2 array, but the present disclosure is not limited thereto. In some other embodiments, the light-splitting structure40corresponds to two photoelectric conversion elements11.

As shown inFIG.1andFIG.2, the solid-state image sensor100includes a light-shielding layer32disposed on the bottom of the grid structure30. The light-shielding layer32may include metal and may be referred to as a metal grid structure. For example, the metal may include gold (Au), nickel (Ni), platinum (Pt), palladium (Pd), iridium (Ir), titanium (Ti), chromium (Cr), tungsten (W), aluminum (Al), copper (Cu), the like, an alloy thereof, or a combination thereof, but the present disclosure is not limited thereto.

As shown inFIG.2, the solid-state image sensor100includes condensing structures50disposed above the color filter layer20. The condensing structure50may include glass, epoxy resin, silicone resin, polyurethane, any other applicable material, or a combination thereof, but the present disclosure is not limited thereto. For example, the condensing structure50may be formed by a photoresist reflow method, a hot embossing method, any other applicable method, or a combination thereof. Moreover, the steps of forming the condensing structure50may include a spin coating process, a lithography process, an etching process, any other applicable process, or a combination thereof, but the present disclosure is not limited thereto.

As shown inFIG.2, in some embodiments, each condensing structure50corresponds to one color filter segment (e.g., red color filter segment20SR, green color filter segment20SG, or blue color filter segment20SB). Similarly, in some embodiments (e.g., the embodiment shown inFIG.1), each condensing structure50corresponds to four photoelectric conversion elements11, and the four photoelectric conversion elements11form a 2×2 array (which may be referred to as quadratic photo diodes (QPD)), but the present disclosure is not limited thereto. In some other embodiments, each condensing structure50corresponds to two photoelectric conversion elements11(which may be referred to as dual photo diodes (DPD)).

The condensing structure50may be a micro-lens. For example, the micro-lens may include a semi-convex lens or a convex lens, but the present disclosure is not limited thereto. The condensing structure50may also include micro-pyramid structures (e.g., circular cone, quadrangular pyramid, and so on), or micro-trapezoidal structures (e.g., flat top cone, truncated square pyramid, and so on). Alternatively, the condensing structure50may be a gradient-index structure.

FIG.3is a schematic diagram of the energy field distribution of incident light L. Referring toFIG.3, when the incident light L enters the solid-state image sensor100(through the condensing structure50) and contacts the light-splitting structure40, it may be split (divided) into light L1 and light L2. Since the light-splitting structure40includes a transparent dielectric material that has a low refractive index (e.g., between about 1 and about 1.45), the incident light L is only split with low energy loss, and the energy field of the incident light L near the center of the light-splitting structure40may present an evanescent wave as shown inFIG.3.

FIG.4is a top view illustrating a portion of the solid-state image sensor102in accordance with some other embodiments of the present disclosure.FIG.5is a top view illustrating a portion of the solid-state image sensor104in accordance with some other embodiments of the present disclosure.FIG.6is a top view illustrating a portion of the solid-state image sensor106in accordance with some other embodiments of the present disclosure. For example, the solid-state image sensor102shown inFIG.4, the solid-state image sensor104shown inFIG.5, and the solid-state image sensor106shown inFIG.6may have a similar cross-sectional view to the solid-state image sensor100shown inFIG.1.

In other words,FIG.2may also be a cross-sectional view of a portion of the solid-state image sensor102along line B-B′ inFIG.4, a portion of the solid-state image sensor104along line C-C′ inFIG.5, or a portion of the solid-state image sensor106along line D-D′ inFIG.6. Similarly, some components of the solid-state image sensor102, the solid-state image sensor104, and the solid-state image sensor106have been omitted inFIG.4toFIG.6for the sake of brevity.

Referring toFIG.4, the solid-state image sensor102has a similar structure to the solid-state image sensor100shown inFIG.1. The main difference from the solid-state image sensor100shown inFIG.1is that each light-splitting structure40corresponds to two photoelectric conversion elements11, and the two photoelectric conversion elements11form a 1×2 (or 2×1) array. Furthermore, each condensing structure50(not shown inFIG.4) corresponds to two photoelectric conversion elements11(which may be referred to as dual photo diodes (DPD)).

Referring toFIG.5, the solid-state image sensor104has a similar structure to the solid-state image sensor102shown inFIG.4. The main difference from the solid-state image sensor102shown inFIG.4is that from the top view of the solid-state image sensor104(e.g.,FIG.5), the profile of the light-splitting structure40is rectangular. Moreover, in some embodiments, the width W40 of the light-splitting structure40is between about 50 nm and about 200 nm. Take the solid-state image sensor104(which is shown inFIG.5) as an example, the width W40 of the light-splitting structure40is defined as the short side length of the rectangle.

Referring toFIG.6, the solid-state image sensor106has a similar structure to the solid-state image sensor100shown inFIG.1. The main difference from the solid-state image sensor100shown inFIG.1is that from the top view of the solid-state image sensor106(e.g.,FIG.6), the profile of the light-splitting structure40is cross-shaped. That is, from the top view of the solid-state image sensor106(e.g.,FIG.6), the profile of the light-splitting structure40may be formed by two intersecting rectangles. Moreover, in some embodiments, the width W40 of the light-splitting structure40is between about 50 nm and about 200 nm. Take the solid-state image sensor106(which is shown inFIG.6) as an example, the width W40 of the light-splitting structure40is defined as the short side length of each rectangle.

FIG.7is a top view illustrating a portion of the solid-state image sensor108in accordance with some embodiments of the present disclosure.FIG.8is a cross-sectional view CS2 that may illustrate a portion of the solid-state image sensor108in accordance with some embodiments of the present disclosure. For example,FIG.8may be a cross-sectional view of a portion of the solid-state image sensor108along line E-E′ inFIG.7. It should be noted that some components of the solid-state image sensor108have been omitted inFIG.7andFIG.8for the sake of brevity.

Referring toFIG.7andFIG.8, the solid-state image sensor108has a similar structure to the solid-state image sensor100shown inFIG.1. The main difference from the solid-state image sensor100shown inFIG.1is that the solid-state image sensor108further includes an inner pillar45disposed on the bottom of the light-splitting structure40. In some embodiments, the number of inner pillars45is the same as the number of light-splitting structures40, so that there are four inner pillars45disposed on the bottoms of the corresponding light-splitting structures40inFIG.7, but the present disclosure is not limited thereto. In some other embodiments, the number of inner pillars45is different from (less than) the number of light-splitting structures40, which may be adjusted by actual needs.

In some embodiments, the inner pillar45includes nontransparent material. The transmittance of the inner pillar45may be less than about 50%, but the present disclosure is not limited thereto. The inner pillar45disposed on the bottom of the light-splitting structure40may further reduce scattering and crosstalk. The inner pillar45may include the same material or similar to the light-shielding layer32, and may be formed simultaneously with the light-shielding layer32by the same process, but the present disclosure is not limited thereto.

For example, the inner pillar45may include a metal, such as copper (Cu), silver (Ag), and so on, but the present disclosure is not limited thereto. Alternately, the inner pillar45may include a photoresist (e.g., a black photoresist, or any other applicable photoresist which is not transparent), an ink (e.g., a black ink, or any other applicable ink which is not transparent), a molding compound (e.g., a black molding compound, or any other applicable molding compound which is not transparent), a solder mask (e.g., a black solder mask, or any other applicable solder mask which is not transparent), (black-)epoxy polymer, any other applicable material, or a combination thereof.

In some embodiments, from the top view of the solid-state image sensor108(e.g.,FIG.7), the profile of the inner pillar45is square, but the present disclosure is not limited thereto. Moreover, in some embodiments, the width W45 of the inner pillar45is between about 50 nm and about 100 nm. Here, the width W45 of the inner pillar45is defined as the shortest distance of two parallel sides of the inner pillar45. Take the solid-state image sensor108(which is shown inFIG.7) as an example, the width W45 of the inner pillar45is defined as the side length of the square.

As shown inFIG.8, in some embodiments, the height H45 of the inner pillar45is equal to the height H32 of the light-shielding layer32, but the present disclosure is not limited thereto. In some other embodiments, the height H45 of the inner pillar45is lower than the height H32 of the light-shielding layer32. Moreover, in some embodiments, the height H45 of the inner pillar45is less than 150 nm.

FIG.9is a top view illustrating a portion of the solid-state image sensor110in accordance with some embodiments of the present disclosure.FIG.10is a cross-sectional view CS3 that may illustrate a portion of the solid-state image sensor110in accordance with some embodiments of the present disclosure. For example,FIG.10may be a cross-sectional view of a portion of the solid-state image sensor110along line F-F′ inFIG.9. It should be noted that some components of the solid-state image sensor110have been omitted inFIG.9andFIG.10for the sake of brevity.

Referring toFIG.9andFIG.10, the solid-state image sensor110has a similar structure to the solid-state image sensor106shown inFIG.6. That is, from the top view of the solid-state image sensor110(e.g.,FIG.9), the profile of the light-splitting structure40is cross-shaped. The main difference from the solid-state image sensor106shown inFIG.6is that from the top view of the solid-state image sensor110(e.g.,FIG.9), the light-splitting structure40is offset from the corresponding second isolation segments13S2by about 45 degrees. In other words, from the top view of the solid-state image sensor110(e.g.,FIG.9), the included angle θ between the light-splitting structure40and the corresponding second isolation segments13S2is about 45 degrees, but the present disclosure is not limited thereto. In some other embodiments, from the top view of the solid-state image sensor110, the light-splitting structure40is offset from the corresponding second isolation segments13S2by 0 to about 45 degrees.

FIG.11is a top view illustrating a portion of the solid-state image sensor110′ in accordance with some other embodiments of the present disclosure.FIG.12is a cross-sectional view CS3′ that may illustrate a portion of the solid-state image sensor110′ in accordance with some other embodiments of the present disclosure. For example,FIG.12may be a cross-sectional view of a portion of the solid-state image sensor110′ along line F-F′ inFIG.11. It should be noted that some components of the solid-state image sensor110′ have been omitted inFIG.11andFIG.12for the sake of brevity.

Referring toFIG.11andFIG.12, the solid-state image sensor110′ has a similar structure to the solid-state image sensor110shown inFIG.9. The main difference from the solid-state image sensor110shown inFIG.9is that the solid-state image sensor110′ further includes an inner pillar45disposed on the bottom of the light-splitting structure40. Moreover, from the top view of the solid-state image sensor110′ as shown inFIG.11, the inner pillar45is disposed on the center of the light-splitting structure40. In this embodiment, the number of inner pillars45is the same as the number of light-splitting structures40, so that there are four inner pillars45disposed on the bottoms of the corresponding light-splitting structures40inFIG.11, but the present disclosure is not limited thereto.

FIG.13is a top view illustrating a portion of the solid-state image sensor112in accordance with some embodiments of the present disclosure.FIG.14is a cross-sectional view CS4 that may illustrate a portion of the solid-state image sensor112in accordance with some embodiments of the present disclosure. For example,FIG.14may be a cross-sectional view of a portion of the solid-state image sensor112along line G-G′ inFIG.13. It should be noted that some components of the solid-state image sensor112have been omitted inFIG.13andFIG.14for the sake of brevity.

Referring toFIG.13andFIG.14, the solid-state image sensor112has a similar structure to the solid-state image sensor100shown inFIG.1. The main difference from the solid-state image sensor100shown inFIG.1is that the light-splitting structure40of the solid-state image sensor112has a first portion41and a second portion42. As shown inFIG.13andFIG.14, the first portion41is disposed on the center of the color filter segment (e.g., red color filter segment20SR, green color filter segment20SG, or blue color filter segment20SB), and the second portion42is disposed near at least one corner of the color filter segment. For example, as shown inFIG.10, there are four second portions42disposed near four corners in each color filter segment, but the present disclosure is not limited thereto. The number of second portions42and the positions of these second portions42may be adjusted according to actual needs.

FIG.15is a top view illustrating a portion of the solid-state image sensor112′ in accordance with some other embodiments of the present disclosure.FIG.16is a cross-sectional view CS4′ that may illustrate a portion of the solid-state image sensor112′ in accordance with some other embodiments of the present disclosure. For example,FIG.16may be a cross-sectional view of a portion of the solid-state image sensor112′ along line G-G′ inFIG.15. It should be noted that some components of the solid-state image sensor112′ have been omitted inFIG.15andFIG.16for the sake of brevity.

Referring toFIG.15andFIG.16, the solid-state image sensor112′ has a similar structure to the solid-state image sensor112shown inFIG.13. The main difference from the solid-state image sensor112shown inFIG.13is that the solid-state image sensor112′ further includes an inner pillar45disposed on the bottom of the light-splitting structure40. In more detail, the inner pillar45disposed on the bottom of the first portion41of the light-splitting structure40. Moreover, from the top view of the solid-state image sensor112′ as shown inFIG.15, the inner pillar45is disposed on the center of first portion41of the light-splitting structure40. In this embodiment, the number of inner pillars45is the same as the number of first portions41of the light-splitting structure40, so that there are four inner pillars45disposed on the bottoms of the corresponding first portions41inFIG.15, but the present disclosure is not limited thereto.

In the foregoing embodiments, the height H20 of the color filter layer20is equal to the height H30 of the grid structure30, and the height H40 of the light-splitting structure40is lower than the height H20 of the color filter layer20(or the height H30 of the grid structure30), but the present disclosure is not limited thereto.FIG.17is a cross-sectional view CS5that may illustrate a portion of the solid-state image sensor in accordance with some embodiments of the present disclosure. For example, the cross-sectional view CS5show inFIG.17may replace the cross-sectional view CS1shown inFIG.2as the cross-sectional view of the solid-state sensing devices100,102,104, or106, but the present disclosures is not limited thereto.

In the embodiment shown inFIG.17, the height H40 of the light-splitting structure40is equal to the height H30 of the grid structure30, and the height H40 of the light-splitting structure40(or the height H30 of the grid structure30) is lower than the height H20 of the color filter layer20, but the present disclosure is not limited thereto.

FIG.18is a top view illustrating a portion of the solid-state image sensor114in accordance with some embodiments of the present disclosure.FIG.19is a cross-sectional view CS6 that may illustrate a portion of the solid-state image sensor114in accordance with some embodiments of the present disclosure. For example,FIG.19may be a cross-sectional view of a portion of the solid-state image sensor114along line H-H′ inFIG.18. It should be noted that some components of the solid-state image sensor114have been omitted inFIG.18andFIG.19for the sake of brevity.

Referring toFIG.18andFIG.19, the solid-state image sensor114has a similar structure to the solid-state image sensor100shown inFIG.1andFIG.2. The main difference from the solid-state image sensor100shown inFIG.1andFIG.2is that in the solid-state image sensor114, the grid structure30has a shift S1with respect to the corresponding first isolation segments13S1, and the light-splitting structure40has a shift S2with respect to the corresponding second isolation segment13S2.

Here, the shift S1may be defined as the distance d1 between the central axis C30of the grid structure30and the central axis C13S1of the corresponding first isolation segments13S1, and the shift S2may be defined as the distance d2 between the central axis C40of the light-splitting structure40and the central axis C13S2of the corresponding second isolation segment13S2. In the embodiment shown inFIG.18andFIG.19, the shift S1is the same as the shift S2. That is, the distance d1 between the central axis C30of the grid structure30and the central axis C13S1of the corresponding first isolation segments13S1is equal to the distance d2 between the central axis C40of the light-splitting structure40and the central axis C13S2of the corresponding second isolation segment13S2, but the present disclosure is not limited thereto.

In some embodiments, the solid-state image sensor100shown inFIG.1andFIG.2and the solid-state image sensor114shown inFIG.18andFIG.19may be different regions of the same solid-state image sensor. For example, the solid-state image sensor100shown inFIG.1andFIG.2may be the central region of the solid-state image sensor, and the solid-state image sensor114shown inFIG.18andFIG.19may be the peripheral (edge) region of the solid-state image sensor, but the present disclosure is not limited thereto.

FIG.20is a top view illustrating a portion of the solid-state image sensor116in accordance with some embodiments of the present disclosure.FIG.21is a cross-sectional view CS7 that may illustrate a portion of the solid-state image sensor116in accordance with some embodiments of the present disclosure. For example,FIG.21may be a cross-sectional view of a portion of the solid-state image sensor116along line I-I′ inFIG.20. It should be noted that some components of the solid-state image sensor116have been omitted inFIG.20andFIG.21for the sake of brevity.

In the solid-state image sensor116, the grid structure30has a shift S1with respect to the corresponding first isolation segments13S1, one light-splitting structure40′ does not have a shift with respect to the corresponding second isolation segment13S2, and another light-splitting structure40″ has a shift S2′ with respect to the corresponding second isolation segment13S2. That is, the distance between the central axis C40′ of the light-splitting structure40′ and the central axis C13S2of the corresponding second isolation segment13S2is 0, the distance d2′ between the central axis C40″ of the light-splitting structure40″ and the central axis C13S2of the corresponding second isolation segment13S2is greater than 0. In other words, the shift S2/S2′ may be variable. Moreover, in the embodiment shown inFIG.20andFIG.21, the shift S1is different from the shift S2′.

In the foregoing embodiments (e.g.,FIGS.1,4-7,9,11,13,15,18, or20), one red color filter segment20SR, two green color filter segments20SG, and one blue color filter segment20SB of the color filter layer20form a 2×2 array, which may be referred to as a 4C quadratic photo diodes (QPD) or dual photo diodes (DPD), but the present disclosure is not limited thereto.

FIG.22is a top view illustrating a portion of the solid-state image sensor118in accordance with some other embodiments of the present disclosure. Referring toFIG.22, eight green color filter segments20SG form two 2×2 arrays, four red color filter segments20SR form a 2×2 array, and four blue color filter segments20SB form a 2×2 array. As shown inFIG.22, the light-splitting structures40are disposed in all color filter segments, but the present disclosure is not limited thereto. In some other embodiments, the light-splitting structures40may be disposed merely in some color filter segments.

Moreover, the forgoing color filter segments (i.e., red color filter segments20SR, green color filter segments20SG, and blue color filter segments20SB) form a 4×4 array, which may be referred to as a16C quadratic photo diodes (QPD) or dual photo diodes (DPD), but the present disclosure is not limited thereto. The number and arrangement of color filter segments may be adjusted according to the actual needs.

In the foregoing embodiments, the light-splitting structures40are disposed in all color filter segments, but the present disclosure is not limited thereto.FIGS.23A-23Fare top views illustrating a portion of the solid-state image sensors120-130in accordance with some other embodiments of the present disclosure. Similarly, some components of the solid-state image sensor120-130have been omitted inFIGS.23A-23Ffor the sake of brevity.

As shown inFIG.23A, two light-splitting structures40are disposed in two green color filter segments20S. As shown inFIG.23B, one light-splitting structure40is disposed in one red color filter segment20R. As shown inFIG.23C, one light-splitting structure40is disposed in one blue color filter segment20B. As shown inFIG.23D, three light-splitting structures40are disposed in two green color filter segments20S and one blue color filter segment20B. As shown inFIG.23E, three light-splitting structures40are disposed in two green color filter segments20S and one red color filter segment20R. As shown inFIG.23F, two light-splitting structures40are disposed in one red color filter segment20R and one blue color filter segment20B.

FIG.24is a top view illustrating a portion of the solid-state image sensor132in accordance with some embodiments of the present disclosure.FIG.25is a cross-sectional view CS8 that may illustrate a portion of the solid-state image sensor132in accordance with some embodiments of the present disclosure. For example,FIG.25may be a cross-sectional view of a portion of the solid-state image sensor132along line J-J′ inFIG.24. It should be noted that some components of the solid-state image sensor132have been omitted inFIG.24andFIG.25for the sake of brevity.

Referring toFIG.24andFIG.25, the solid-state image sensor132has a similar structure to the solid-state image sensor100shown inFIG.1. The main difference from the solid-state image sensor100shown inFIG.1is that the solid-state image sensor132further includes an auxiliary light-splitting structure44disposed on the bottom of the light-splitting structure40. The auxiliary light-splitting structure44may include a transparent dielectric material, but the present disclosure is not limited thereto. In some embodiments, the auxiliary light-splitting structure44includes at least one material that is different from the light-splitting structure40, and the refractive index of the auxiliary light-splitting structure44is between about 1 and about 1.65.

In some embodiments, from the top view of the solid-state image sensor132(e.g.,FIG.24), the profile of the auxiliary light-splitting structure44is square, but the present disclosure is not limited thereto. In other words, from the top view of the solid-state image sensor132, the profile of the auxiliary light-splitting structure44may be the same as or similar to the profile of the light-splitting structure40, but the present disclosure is not limited thereto. Moreover, in some embodiments, the width W44 of the auxiliary light-splitting structure44is equal to or greater than the width W40 of the light-splitting structure40. For example, the width W44 of the auxiliary light-splitting structure44may be between about 70 nm and about 300 nm. Here, the width W44 of the auxiliary light-splitting structure44is defined as the shortest distance of two parallel sides of the auxiliary light-splitting structure44. Take the solid-state image sensor132(which is shown inFIG.24) as an example, the width W44 of the auxiliary light-splitting structure44is defined as the side length of the square.

As shown inFIG.25, in some embodiments, the height H44 of the auxiliary light-splitting structure44is between about 50 nm and about 350 nm. Moreover, as shown inFIG.24andFIG.25, in some embodiments, the auxiliary light-splitting structure44is further disposed on the bottom of the grid structure30. That is, the auxiliary light-splitting structure44may cover at least a portion of the light-shielding layer32, but the present disclosure is not limited thereto.

FIG.26is a top view illustrating a portion of the solid-state image sensor132′ in accordance with some other embodiments of the present disclosure.FIG.27is a cross-sectional view CS8′ that may illustrate a portion of the solid-state image sensor132′ in accordance with some other embodiments of the present disclosure. For example,FIG.27may be a cross-sectional view of a portion of the solid-state image sensor132′ along line K-K′ inFIG.26. It should be noted that some components of the solid-state image sensor132′ have been omitted inFIG.26andFIG.27for the sake of brevity.

Referring toFIG.26andFIG.27, the solid-state image sensor132′ has a similar structure to the solid-state image sensor132shown inFIG.24. The main difference from the solid-state image sensor132shown inFIG.24is that the solid-state image sensor132′ further includes an inner pillar45disposed on the bottom of the light-splitting structure40. That is, the auxiliary light-splitting structure44may cover at least a portion of the inner pillar45, but the present disclosure is not limited thereto.

In the foregoing embodiments, the light-shielding layer32is disposed on the bottom of the grid structure30, but the present disclosure is not limited thereto.FIG.28is a top view illustrating a portion of the solid-state image sensor134in accordance with some other embodiments of the present disclosure.FIG.29is a cross-sectional view CS9 that may illustrate a portion of the solid-state image sensor134in accordance with some other embodiments of the present disclosure. For example,FIG.29may be a cross-sectional view of a portion of the solid-state image sensor134along line L-L′ inFIG.28. It should be noted that some components of the solid-state image sensor134have been omitted inFIG.28andFIG.29for the sake of brevity.

Referring toFIG.28andFIG.29, the solid-state image sensor134has a similar structure to the solid-state image sensor100shown inFIG.1. The main difference from the solid-state image sensor100shown inFIG.1is that the solid-state image sensor134includes no light-shielding layer32disposed on the bottom of the grid structure30. Similarly, in some other embodiments, the solid-state image sensor134further includes an inner pillar45disposed on the bottom of the light-splitting structure40(not shown inFIG.28andFIG.29). Other similar features will not be repeated here.

FIG.30is a top view illustrating a portion of the solid-state image sensor136in accordance with some other embodiments of the present disclosure.FIG.31is a cross-sectional view CS10that may illustrate a portion of the solid-state image sensor136in accordance with some other embodiments of the present disclosure. For example,FIG.31may be a cross-sectional view of a portion of the solid-state image sensor136along line L-L′ inFIG.30. It should be noted that some components of the solid-state image sensor136have been omitted inFIG.30andFIG.31for the sake of brevity.

Referring toFIG.30andFIG.31, the solid-state image sensor136has a similar structure to the solid-state image sensor134shown inFIG.28. The main difference from the solid-state image sensor134shown inFIG.28is that the solid-state image sensor136further includes an auxiliary light-splitting structure44disposed on the bottom of the light-splitting structure40. Moreover, as shown inFIG.30andFIG.31, in some embodiments, the auxiliary light-splitting structure44is further disposed on the bottom of the grid structure30.

In summary, the solid-state image sensor of the embodiments of the present disclosure includes a light-splitting structure disposed in (the color filter segment of) the color filter layer, which may effectively reduce scattering and crosstalk, thereby improving the quality of the image signal from the photoelectric conversion elements of the solid-state image sensors.

The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure. Therefore, the scope of protection should be determined through the claims. In addition, although some embodiments of the present disclosure are disclosed above, they are not intended to limit the scope of the present disclosure.