Image sensing structure and forming method thereof

Abstract

The invention provides an image sensing structure. The image sensing structure includes a first pixel and a second pixel. The first pixel includes a first photodiode, a second photodiode, and a first isolation member. The first isolation member is disposed between the first photodiode and the second photodiode and extends in the first direction. The second pixel is disposed adjacent to the first pixel and includes a third photodiode, a fourth photodiode, and a second isolation member. A second isolation member is disposed between the third photodiode and the fourth photodiode and extends in a second direction substantially perpendicular to the first direction. The embodiment of the invention also provides a method for forming the image sensing structure.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to image sensing structures and methods of forming the same. Background Art

[0002] CMOS image sensors are used in many types of electronic devices, such as video cameras and digital cameras, to capture images.

[0003] As technology standards advance, consumer demand for image sensing devices that take up less space, consume less power, and produce higher-quality images at faster speeds continues to increase. Therefore, there remains a need to develop CMOS image sensors with improved structures. Summary of the Invention

[0004] Some embodiments of the present disclosure provide an image sensing structure, which includes: a first pixel, including a first photodiode, a second photodiode and a first isolation member, the first isolation member is arranged between the first photodiode and the second photodiode and extends along a first direction; and a second pixel, arranged to be adjacent to the first pixel and including a third photodiode, a fourth photodiode and a second isolation member, the second isolation member is arranged between the third photodiode and the fourth photodiode and extends along a second direction substantially perpendicular to the first direction.

[0005] Other embodiments of the present disclosure provide an image sensing structure, which includes: a first sensing member, including a plurality of first pixels adjacent to and separated from each other, wherein each of the plurality of first pixels includes a first photodiode, a second photodiode and a first isolation member, and the first isolation member is arranged between the first photodiode and the second photodiode; and a second sensing member, adjacent to the first sensing member, and including a plurality of second pixels adjacent to and separated from each other, wherein each of the plurality of second pixels includes a third photodiode, a fourth photodiode and a second isolation member, and the second isolation member is arranged between the third photodiode and the fourth photodiode, wherein at least one of the first isolation members extends along a first direction, and at least one of the second isolation members extends along a second direction substantially perpendicular to the first direction.

[0006] Another embodiment of the present disclosure provides a method for forming an image sensing structure, the method comprising: providing a substrate having a first surface and a second surface opposite to the first surface; forming a first photodiode and a second photodiode in the substrate; forming a third photodiode and a fourth photodiode in the substrate; forming a first isolation member, the first isolation member being within the substrate and extending between the first photodiode and the second photodiode; and forming a second isolation member adjacent to the first isolation member, the second isolation member being within the substrate and extending between the third photodiode and the fourth photodiode, wherein the first isolation member extends along a first direction and the second isolation member extends along a second direction substantially perpendicular to the first direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Aspects of the present disclosure will be best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be noted that, in accordance with standard practice in the industry, the various components are not drawn to scale. In fact, the dimensions of the various components may be arbitrarily increased or reduced for clarity of discussion.

[0008] Figure 1 is a schematic top view of a portion of an image sensing structure according to some embodiments of the present disclosure.

[0009] Figure 2 According to some embodiments of the present disclosure Figure 1 Schematic cross-sectional view of a portion of the image sensing structure along line AA′ in FIG.

[0010] Figure 3 According to some embodiments of the present disclosure Figure 1 Schematic cross-sectional view of a portion of the image sensing structure along line BB′ in FIG.

[0011] Figure 4 is a schematic top view of a color filter array (CFA) showing another image sensing structure according to some embodiments of the present disclosure.

[0012] Figure 5A and Figure 5B According to some embodiments of the present disclosure Figure 4 An enlarged top view of parts R10 and R20.

[0013] Figure 6A According to some embodiments of the present disclosure Figure 4 Schematic cross-sectional view of portion R10 taken along line CC′.

[0014] Figure 6B According to some embodiments of the present disclosure Figure 6A Schematic stereogram of .

[0015] Figure 7A According to some embodiments of the present disclosure Figure 4 Schematic cross-sectional view of portion R20 along line DD′ in FIG.

[0016] Figure 7B According to some embodiments of the present disclosure Figure 7A Schematic stereogram of .

[0017] Figures 8 to 10 According to some embodiments of the present disclosure Figure 4 Schematic three-dimensional view of the various parts R30, R40 and R50.

[0018] Figure 11 is a schematic top view of a CFA showing another image sensing structure according to some embodiments of the present disclosure.

[0019] Figure 12A According to some embodiments of the present disclosure Figure 11 Schematic cross-sectional view of portion R60 taken along line EE′.

[0020] Figure 12B According to some embodiments of the present disclosure Figure 12A Schematic stereogram of .

[0021] Figure 13A According to some embodiments of the present disclosure Figure 11 Schematic cross-sectional view of portion R70 taken along line FF′ in FIG.

[0022] Figure 13B According to some embodiments of the present disclosure Figure 13A Schematic stereogram of .

[0023] Figure 14 and Figure 15 According to some embodiments of the present disclosure Figure 11 Schematic perspective view of parts R80 and R90.

[0024] Figure 16 is a schematic top view of a CFA showing another image sensing structure according to some embodiments of the present disclosure.

[0025] Figure 17 is a schematic top view of a CFA showing another image sensing structure according to some embodiments of the present disclosure.

[0026] Figure 18A According to some embodiments of the present disclosure Figure 17 An enlarged view of portion R120 of the image sensing structure.

[0027] Figure 18B and Figure 18CAccording to some embodiments of the present disclosure Figure 18A Schematic cross-sectional and perspective views of .

[0028] Figure 19A and Figure 19B According to some embodiments of the present disclosure Figure 17 Schematic cross-sectional view and perspective view of another portion R130 of the image sensing structure.

[0029] Figure 20 is a flow chart showing a method of forming an image sensing structure according to some embodiments of the present disclosure.

[0030] Figures 21 to 27 is an illustration according to some embodiments of the present disclosure Figure 20 Schematic cross-sectional or top view of sequential operations of the method.

[0031] Figure 28 is a schematic perspective diagram illustrating a combination of two image sensing structures according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0032] The following disclosure provides many different embodiments or examples of different components for implementing the provided subject matter. Specific examples of components and arrangements are described below to simplify the disclosure. Of course, these are merely examples and are not intended to be limiting. For example, in the following description, forming a first component above or on a second component may include an embodiment in which the first component and the second component are directly in contact with each other, and may also include an embodiment in which an additional component may be formed between the first component and the second component so that the first component and the second component may not be in direct contact. In some embodiments, the present disclosure may repeat reference numerals and / or characters in various examples. This repetition is for the purpose of clarity and simplicity and does not, in itself, indicate a relationship between the individual embodiments and / or configurations being discussed.

[0033] Furthermore, for ease of description, spatially relative terms such as "below," "beneath," "lower," "above," and "upper" may be used herein to describe the relationship of one element or component to another element or component as illustrated in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein should likewise be interpreted accordingly.

[0034] Although the numerical ranges and parameters setting forth the broad scope of the present disclosure are approximate, the numerical values ​​set forth in the specific examples are reported as accurately as possible. However, any numerical value inherently contains certain errors, which are necessarily caused by the standard deviation found in the corresponding test measurements. In addition, as used herein, the terms "substantially," "approximately," and "about" generally mean within a value or range that would be considered by one of ordinary skill in the art. Alternatively, the terms "substantially," "approximately," and "approximately" mean within an acceptable standard error of the mean value when considered by one of ordinary skill in the art. One of ordinary skill in the art will appreciate that acceptable standard errors may vary depending on the technology. Except in the operating / working examples, or unless otherwise expressly provided, all numerical ranges, amounts, values, and percentages disclosed herein, such as material amounts, durations, temperatures, operating conditions, amount ratios, etc., should in all cases be understood to be modified by "substantially," "approximately," and "approximately." Accordingly, unless otherwise indicated, the numerical parameters set forth in this disclosure and the appended claims are approximate values ​​that may vary as needed. At a minimum, each numerical parameter should be interpreted in light of the number of reported significant figures and by applying ordinary rounding techniques. Ranges may be expressed herein as from one endpoint to the other endpoint or between two endpoints. Unless otherwise stated, all ranges disclosed herein include the endpoints.

[0035] CMOS image sensors can be designed with multiple dual photodiodes (DPDs) arranged in an array. Dual photodiodes absorb more light than a single photodiode with the same number of pixels. Therefore, dual photodiodes provide a more efficient mechanism for generating light-induced charge. CMOS image sensors with DPDs can reduce noise and capture images with vivid colors.

[0036] Figure 1 is a schematic top view of a portion of image sensing structure 100, and Figure 2 It is along Figure 1 Schematic cross-sectional view of a portion of the image sensing structure 100 along line AA′ in FIG. In some embodiments, the image sensing structure 100 is an image sensing device or a portion thereof. The image sensing structure 100 is, for example, a backside illuminated (BSI) image sensing structure. Figure 1A portion of an image sensing structure 100 in a color filter array (CFA) 127A is shown. In some embodiments, the image sensing structure 100 includes an optical portion P1, a pixel portion P2, and a circuit portion P3. The pixel portion P2 is located between the optical portion P1 and the circuit portion P3. The pixel portion P2 includes a substrate 10 having a first surface S1 and a second surface S2 opposite the first surface S1. The substrate 10 includes any type of semiconductor body, such as a silicon wafer or one or more dies on the wafer, and any other type of semiconductor and / or epitaxial layer formed thereon and / or otherwise associated therewith. In some embodiments, the substrate 10 is doped with p-type impurities and thus forms a p-type substrate.

[0037] Several isolation structures 21 are disposed within the substrate 10. In some embodiments, the isolation structures 21 are deep trench isolation (DTI) structures. In some embodiments, the isolation structures 21 extend along a first direction D1 between the first surface S1 and the second surface S2 of the substrate 10. In some embodiments, the isolation structures 21 extend from the second surface S2 toward the substrate 10 to a predetermined depth. In some embodiments, the first direction D1 is a direction along the thickness of the substrate 10 or the height of the image sensing structure 100. The isolation structures 21 are formed of, for example, an oxide, a nitride, a high-k dielectric material such as aluminum oxide (AlO), tantalum oxide (TaO), hafnium oxide (HfO), hafnium silicon oxide (HfSiO), hafnium aluminum oxide (HfAlO), hafnium tantalum oxide (HfTaO), or a combination thereof.

[0038] The isolation structure 21 divides the substrate 10 into a plurality of pixel regions 20. In some embodiments, the isolation structure 21 and the pixel regions 20 are alternately arranged along a second direction D2 perpendicular to the first direction D1. Thus, the isolation structure 21 can be referred to as an inter-pixel DTI structure. The isolation structure 21 is arranged along a third direction D3 perpendicular to the first direction D1 and the second direction D2 (i.e., into the pixel region 20). Figure 2 of paper) extension.

[0039] In some embodiments, pixel regions 20 are formed by providing substrate 10 with dopant impurities, wherein the dopant impurities have a conductivity type opposite to that of substrate 10. In some embodiments, pixel regions 20 are doped with n-type impurities. Due to the opposite dopant types, a PN junction is formed between substrate 10 and pixel regions 20. Thus, each pixel region 20 includes a PN junction. The PN junction comprises a photodiode. In some embodiments, pixel region 20 is a light sensing layer. Isolation structure 21 is used to optically isolate pixel region 20 from adjacent pixel regions 20.

[0040] Several isolation members 23 are disposed within the substrate 10. The isolation members 23 are formed of a material that is different from or the same as the material of the isolation structure 21. In some embodiments, the isolation members 23 extend between the first surface S1 and the second surface S2 of the substrate 10 along a first direction D1. In some embodiments, the isolation members 23 extend from the second surface S2 of the substrate 10 toward the substrate 10 to a predetermined depth. In some embodiments, the length L1 of the isolation members 23 is substantially less than the length L2 of the isolation structure 21, as shown in FIG. Figure 2 In other embodiments, the length L1 of the isolation member 23 is substantially equal to or greater than the length L2 of the isolation structure 21. In some embodiments, the isolation member 23 is parallel to the isolation structure 21 along the third direction D3.

[0041] In some embodiments, an isolation member 23 is disposed within each pixel region 20 and surrounded by an isolation structure 21. The isolation member 23 divides the pixel region 20 into at least two photodiode regions 22. The two photodiode regions 22 in one pixel region 20 are referred to as a dual photodiode (DPD). Therefore, the isolation member 23 is referred to as an in-pixel DTI structure.

[0042] The photodiode region 22 is used to convert radiation entering the substrate 10 from the second surface S2 of the substrate 10 into an electrical signal. When incident light (including photons with sufficient energy) strikes the photodiode region 22, electron-hole pairs are generated.

[0043] In some embodiments, the optical portion P1 includes an anti-reflection layer 24, a plurality of metal grids 25, one or more dielectric layers 26, a plurality of color filters 27, and a plurality of microlenses 28. The anti-reflection layer 24 is disposed on the second surface S2 of the substrate 10. In some embodiments, the anti-reflection layer 24 is formed of an oxide, a nitride, a high-k dielectric material such as aluminum oxide (AlO), tantalum oxide (TaO), hafnium oxide (HfO), hafnium silicon oxide (HfSiO), hafnium aluminum oxide (HfAlO), hafnium tantalum oxide (HfTaO), or a combination thereof. The anti-reflection layer 24 serves to minimize light reflection and thereby allow more light to reach the pixel portion P2.

[0044] In some embodiments, a metal grid 25 is disposed on the anti-reflective layer 24 and aligned with each of the isolation structures 21. The metal grid 25 is formed of tungsten (W), copper (Cu), or aluminum copper (AlCu). The metal grid 25 can be used to reduce optical interference between one pixel region 20 and an adjacent pixel region 20. The metal grid 25 is used to reflect refracted light or reflected light back to the color filter 27, thereby improving optical isolation between adjacent pixels.

[0045] Color filters 27 are disposed on the anti-reflection layer 24 and adjacent to the metal grid 25. Adjacent pairs of color filters 27 are separated by one metal grid 25. The space above the metal grid 25 is filled with a dielectric layer 26 made of oxide. The color filters 27 are separated from the substrate 10 or the pixel region 20 by the anti-reflection layer 24.

[0046] In other embodiments, the dielectric layer 26 is disposed on the anti-reflective layer 24. In such embodiments, the metal grids 25 are individually embedded in the dielectric layer 26 and aligned with the isolation structure 21. That is, the dielectric layer 26 separates the metal grids 25 from the substrate 10. The color filter 27 is surrounded by the dielectric layer 26, and the top surface of the color filter 27 is coplanar with or below the top surface of the dielectric layer 26.

[0047] In some embodiments, the color filter 27 is aligned with the pixel region 20. The color filter 27 is disposed above the two photodiode regions 22 and the isolation member 23 between the two photodiode regions 22. This arrangement can increase the radiation of incident light onto the pixel region 20. The color filter 27 is configured to allow light or radiation having a wavelength within a specific range to pass through. For example, the color filter 27 configured to transmit incident light having a wavelength between approximately 620 nanometers (nm) and approximately 750 nm (i.e., red light) is referred to as a red filter 27R. The color filter 27 configured to transmit incident light having a wavelength between approximately 495 nm and approximately 570 nm (i.e., green light) is referred to as a green filter 27G. The color filter 27 configured to transmit incident light having a wavelength between approximately 450 nm and approximately 495 nm (i.e., blue light) is referred to as a blue filter 27B. The red filter 27R, the green filter 27G, and the blue filter 27B are illustrated in the figures and described below.

[0048] In some embodiments, microlens 28 is disposed on portions of color filter 27 and dielectric layer 26. Microlens 28 has a curved surface (or convex surface) that guides an incident light beam and promotes light beam convergence. Microlens 28 is aligned with color filter 27 and pixel region 20. This arrangement can increase the radiation of the light beam on pixel region 20. Since paired photodiode regions 22 are formed in a single pixel region 20, one color filter 27 is disposed above the two photodiode regions 22, and one microlens 28 is disposed above the two photodiode regions 22.

[0049] In some embodiments, circuit portion P3 includes one or more transistors T10, one or more interlayer dielectric (ILD) layers 42, and a plurality of conductive lines 44. Transistors T10 are disposed on the first surface S1 of substrate 10 and surrounded by ILD layer 42. Wires 44 are interconnected and embedded in ILD layer 42. ILD layer 42 is formed of an oxide or a suitable material. Wires 44 are formed of a metal or an alloy.

[0050] Although Figure 2 Although not specifically shown, transistor T10 includes a transfer transistor serving as a transfer gate, a reset transistor serving as a reset gate, a source follower transistor serving as a source follower gate (amplifier gate), and a select transistor serving as a select gate. Some or all of these transistors are provided in circuit portion P3. In some embodiments, floating node (or floating diffusion region) 14 is provided in pixel portion P2.

[0051] In some embodiments, floating node 14 is used to store charge transferred and generated from pixel region 20. The charge stored in floating node 14 is then converted into a voltage signal. Multiple pixel regions 20 can measure different components of a light beam based on the multiple voltage signals converted by floating node 14. The voltage signals can be read or processed by circuit portion P3 of image sensing structure 100. Thus, image sensing structure 100 can provide measurement results for generating a 2D or 3D image of a scene.

[0052] like Figure 1 As shown, all isolation members 23 extend along a third direction D3. In some embodiments, isolation members 23 are perpendicular to some isolation structures 21. CFA 127A can separate individual colors from a color image. The resulting output from image sensing structure 100 with CFA 127A can be interpolated to form a full-color image. In some embodiments, CFA 127A is a square arrangement of red filter 27R, green filter 27G, and blue filter 27B above the image sensing structure (i.e., photodiode region 22). Red filter 27R, green filter 27G, and blue filter 27B each allow incident light within a specific wavelength range to pass. Pixel region 20 corresponding to red filter 27R is red pixel region 20R (or simply red pixel), pixel region 20 corresponding to green filter 27G is green pixel region 20G (or simply green pixel), and pixel region 20 corresponding to blue filter 27B is blue pixel region 20B (or simply blue pixel). Every four red pixel regions 20R form a 2×2 red pixel unit 120R, every four green pixel regions 20G form a 2×2 green pixel unit 120G, and every four blue pixel regions 20B form a 2×2 blue pixel unit 120B.

[0053] Figure 3 for Figure 1 FIG. 1 is a schematic cross-sectional view of a portion of the image sensing structure 100 along line BB′. Figure 3 Used to illustrate the operating principle of the image sensing structure 100. In some embodiments, the light beam hv is incident on the second surface S2 of the substrate 10 through the microlens 28, the red filter 27R / the green filter 27G and the anti-reflection layer 24 in sequence. The first light beam hv1 (i.e., the red light in the light beam hv) can pass through the red filter 27R, and the second light beam hv2 (i.e., the green light in the light beam hv) can pass through the green filter 27G. After the first light beam hv1 passes through the red filter 27R, it is split into at least two red light beams hv1a and hv1b. After the second light beam hv2 passes through the green filter 27G, it is split into at least two green light beams hv2a and hv2b. Figure 2 , the photodiode regions 22 corresponding to the red filter 27R, the green filter 27G, and the blue filter 27B are represented as photodiode region 22R, photodiode region 22G, and photodiode region 22B, respectively. Then, the red light beams hv1a and hv1b interact with the photodiode region 22R. Then, the green light beams hv2a and hv2b interact with the photodiode region 22G. As a result, the photodiode regions 22R and 22G generate a plurality of photoinduced carriers (e.g., electrons) and collect the plurality of photoinduced carriers (e.g., electrons), and then the photoinduced carriers are transferred from the pixel regions 20R and 20G to the floating node 14.

[0054] The circuit portion P3 processes signals of photoinduced carrier generation in the pixel portion P2 and performs any appropriate operation based on these signals.

[0055] The isolation structure 21 is used to reflect the refracted light or the reflected light back to the pixel region 20 , and thus can increase the full well capacity of the image sensing structure 100 and thus improve the optical isolation of adjacent pixels.

[0056] However, in some cases, due to the diffraction behavior of the red light beams hv1a and hv1b, they may not be able to propagate in a straight line along the substrate 10 from the second surface S2 toward the first surface S1. Light with a longer wavelength is more likely to diffract or penetrate obstacles. Accordingly, light with a longer wavelength can reach a greater depth of the substrate 10. The red light beams hv1a and hv1b tend to penetrate the isolation structure 21 and reach other adjacent pixel regions 20. Therefore, despite the use of the isolation structure 21, some red light (such as the red light beams hv1a and hv1b) will still illuminate, for example, the adjacent photodiode region 22G. This phenomenon is called "crosstalk". The red light beams hv1a and hv1b that penetrate the isolation structure 21 cause some photodiode regions 22G illuminated by such red light beams hv1a and hv1b to produce more photoinduced carriers.

[0057] refer to Figure 1 and Figure 3 The red light beams hv1a and hv1b (indicated by arrows) that penetrate adjacent photodiode regions 22G cause some green pixel units 120G to appear brighter. Other green pixel units 120G that are not affected by the red light (i.e., those not indicated by arrows) appear relatively darker. This problem results in uneven brightness across the pixels of image sensing structure 100.

[0058] Figure 4 FIG2 is a schematic top view of CFA 127B illustrating another image sensing structure 110. Image sensing structure 110 is similar to image sensing structure 100, except that image sensing structure 110 has a different orientation of isolation members 23. In some embodiments, image sensing structure 110 includes a plurality of first isolation members 23X extending along a second direction D2 and a plurality of second isolation members 23Y extending along a third direction D3. When viewed from above, first isolation members 23X are perpendicular to second isolation members 23Y.

[0059] Figure 5A and Figure 5B They are Figure 4 For clarity, some components are not shown. Figure 5APortion R10 includes two red pixel regions 20R and two green pixel regions separated by two isolation structures 21 perpendicular to each other. In some embodiments, the red pixel cell 120R includes four second isolation members 23Y extending along the third direction D3, and no first isolation members 23X extending along the second direction D2 are present. The second isolation members 23Y separate the two photodiode regions 22R in each red pixel region 20R. The second isolation member 23Y is located between the two photodiode regions 22R in each red pixel region 20R. In some embodiments, the second isolation members 23Y are connected to the isolation structures 21.

[0060] refer to Figure 5B Portion R20 includes two red pixel regions 20R and two green pixel regions 20G separated by two mutually perpendicular isolation structures 21. In some embodiments, portion R20 includes two first isolation members 23X extending along the second direction D2. The first isolation members 23X separate the two photodiode regions 22R in each red pixel region 20R. The first isolation member 23X is located between the two photodiode regions 22R in each red pixel region 20R. In some embodiments, the first isolation member 23X is connected to the isolation structure 21. In some embodiments, portion R20 includes two second isolation members 23Y extending along the third direction D3. The second isolation member 23Y separates the two photodiode regions 22G in each green pixel region 20G. The second isolation member 23Y is located between the two photodiode regions 22G in each green pixel region 20G. In some embodiments, the second isolation member 23Y is connected to the isolation structure 21. In some embodiments, the thickness T1 of the isolation structure 21 is substantially equal to or greater than the thickness T2 of the first isolation member 23X or the thickness T3 of the second isolation member 23Y. In some embodiments, the thickness T2 of the first isolation member 23X is substantially equal to the thickness T3 of the second isolation member 23Y.

[0061] Figure 6A It is along Figure 4 Schematic cross-sectional view of portion R10 taken along line CC′. Figure 6B yes Figure 6A The isolation structure 21, the first isolation member 23X and the second isolation member 23Y are all embedded in the substrate 10. The isolation structure 21, the first isolation member 23X and the second isolation member 23Y are all strip-shaped walls, such as Figure 6B For the convenience of explanation, only part of the isolation structure 21 is shown in the stereograms mentioned below.

[0062] Reference to the above Figure 3The principle discussed is similar, when the incident light beam hv10 passes through the microlens 28, the red filter 27R and the anti-reflection layer 24, the incident light beam hv10 is split into at least two red light beams hv11 and hv12 by the second isolation member 23Y. The red light beams hv11 and hv12 can penetrate the adjacent photodiode region 22G in the green pixel region 20G located on the opposite side of the isolation structure 21. Therefore, the portion of the green pixel region 20G that receives the additional red light beams (such as hv11 and hv12) will appear brighter. Figure 4 , the portion of the green pixel unit 120G located to the right of portion R10 (near the arrow) will appear brighter than the rest of the green pixel unit 120G.

[0063] Figure 7A for Figure 4 Schematic cross-sectional view of portion R20 along line DD′. Figure 7B for Figure 7A Schematic perspective view of the middle part R20. Figure 3 The principles discussed are similar. When the incident light beam hv20 passes through the microlens 28, the red filter 27R, and the anti-reflection layer 24, the incident light beam hv20 is split by the first isolation member 23X into at least two red light beams hv21 and hv22. The red light beams hv21 and hv22 can penetrate the adjacent photodiode region 22G in the green pixel region 20G located on the opposite side of the isolation structure 21. Therefore, the portion of the green pixel region 20G that receives the additional red light beams (such as hv21 and hv22) will appear brighter. Figure 4 , the portion of the green pixel unit 120G located at the bottom of portion R20 (near the arrow) will appear brighter than the rest of the green pixel unit 120G.

[0064] The image sensing structure 110 includes both a first isolation member 23X and a second isolation member 23Y. Compared to the isolation member 23Y in the portion R10, the first isolation member 23X in the portion R20 is "rotated" by 90 degrees. Thus, in each green pixel unit 120G, the two green pixel regions 20G receive the red light beam from the adjacent red pixel region 20R, as shown in FIG. Figure 4 As shown by the arrow in the middle. As a result, all green pixel cells 120G have substantially the same average brightness (i.e., half are bright and half are dark). This improves the brightness uniformity of the pixels of image sensing structure 110. In some embodiments, when all green pixel cells 120G have the same average brightness, image sensing structure 110 has better color performance than a design in which some green pixel cells 120G are physically bright and others are physically dark.

[0065] Figures 8 to 10 for Figure 4 Schematic perspective view of each part R30, R40 and R50. Figure 4 and Figure 8 Portion R30 includes a red pixel region 20R, two green pixel regions 20G, and a blue pixel region 20B, adjacent to each other and separated by two mutually perpendicular isolation structures 21. Portion R30 includes four second isolation members 23Y extending along the second direction D2 and no first isolation members 23X extending along the first direction D1. Second isolation members 23Y are provided in the red pixel region 20R, the green pixel region 20G, and the blue pixel region 20B.

[0066] refer to Figure 4 and Figure 9 The portion R40 includes a red pixel unit 120R and a green pixel unit 120G adjacent to each other and separated by an isolation structure 21. The portion R40 includes four isolation members 23X extending along the second direction D2 and four isolation members 23Y extending along the third direction D3.

[0067] refer to Figure 4 and Figure 10 Portion R50 includes a red pixel unit 120R and a green pixel unit 120G adjacent to each other and separated by an isolation structure 21. Portion R50 is similar to portion R40, except that, in portion R40, first isolation member 23X is provided in red pixel unit 120R and second isolation member 23Y is provided in green pixel unit 120G; whereas, in portion R50, first isolation member 23X is provided in green pixel unit 120G and second isolation member 23Y is provided in red pixel unit 120R.

[0068] Figure 11 FIG. 1 is a schematic top view of a CFA 127C of another image sensing structure 120. Image sensing structure 120 is similar to image sensing structure 100 or 110, except that image sensing structure 120 has a different orientation of the isolation members. In image sensing structure 120, because both green pixel regions 20G in each green pixel unit 120G receive red light beams from the adjacent red pixel region 20R, all green pixel units 120G have substantially the same average brightness, as shown in FIG. Figure 11 As shown by the arrow in the middle, the brightness uniformity of the pixels of the image sensing structure 120 is improved.

[0069] Figure 12A For the Figure 11 Schematic cross-sectional view of portion R60 along center line EE'. Figure 12B for Figure 12ASchematic perspective view of portion R60 in FIG. Portion R60 is a blue pixel unit 120B, which includes four blue pixel regions 20B adjacent to each other and separated by two isolation structures 21 perpendicular to each other. In some embodiments, portion R60 includes four second isolation members 23Y extending along the third direction D3. Each isolation member 23Y is disposed between two photodiode regions 22B, such as Figure 12A or Figure 12B As shown, the isolation member 23Y separates the two photodiode regions 22B in the blue pixel region 20B. Therefore, there are eight photodiode regions 22B in the portion R60 (blue pixel unit 120B).

[0070] Figure 13A For the Figure 11 Schematic cross-sectional view of portion R70 along center line FF'. Figure 13B for Figure 13A Schematic perspective view of section R70 in FIG. Section R70 is another blue pixel unit 120B similar to section R60, except that section R70 includes four first isolation members 23X extending along the second direction D2. Each first isolation member 23X is disposed between two photodiode regions 22B within the blue pixel region 20B. Compared to the second isolation members 23Y in section R60, the first isolation members 23X in section R70 are "rotated" 90 degrees. Therefore, not only can the isolation members in the red pixel unit 120R be rotated, but also the isolation members in the blue pixel unit 120B can be rotated.

[0071] Figure 14 and Figure 15 for Figure 11 Schematic perspective view of parts R80 and R90. Figure 11 and Figure 14 Portion R80 includes a red pixel region 20R, two green pixel regions 20G, and a blue pixel region 20B, adjacent to each other and separated by two perpendicular isolation structures 21. Portion R80 includes a first isolation member 23X extending along a second direction D2 and three second isolation members 23Y extending along a third direction D3. The first isolation member 23X is provided in the red pixel region 20R, and the second isolation members 23Y are provided in the green pixel region 20G and the blue pixel region 20B.

[0072] refer to Figure 11 and Figure 15Portion R90 includes a red pixel region 20R, two green pixel regions 20G, and a blue pixel region 20B, adjacent to each other and separated by two perpendicular isolation structures 21. Portion R90 includes a first isolation member 23X extending along a second direction D2 and three second isolation members 23Y extending along a third direction D3. The first isolation member 23X is provided in the blue pixel region 20B, and the second isolation members 23Y are provided in the red pixel region 20R and the green pixel region 20G.

[0073] Figure 16 FIG2 is a schematic top view of CFA 127D of another image sensing structure 130. Image sensing structure 130 is similar to image sensing structures 100, 110, or 120, except that image sensing structure 130 has a different orientation of isolation members. In some embodiments, image sensing structure 130 includes portion R100 and portion R110, each of which includes one red pixel cell 120R, two green pixel cells 120G, and one blue pixel cell 120B separated by isolation structure 21. Portion R100 includes multiple second isolation members 23Y extending along a third direction D3 and lacks first isolation members 23X, while portion R110 includes multiple first isolation members 23X extending along a second direction D2 and lacks isolation members 23Y. Compared to the second isolation members 23Y in portion R100, the first isolation members 23X in portion R110 are "rotated" 90 degrees. In the image sensing structure 130, since the two green pixel regions 20G in each green pixel unit 120G receive the red light beams from the adjacent red pixel region 20R, all green pixel units 120G have substantially the same average brightness, as shown in FIG. Figure 16 As shown by the arrow in the middle, the brightness uniformity of the pixels of the image sensing structure 130 is improved.

[0074] Figure 17FIG1 is a schematic top view of CFA 127E illustrating another image sensing structure 140. Image sensing structure 140 is similar to image sensing structures 100, 110, 120, or 130, except that image sensing structure 140 has a different orientation of isolation members. Image sensing structure 140 includes a plurality of red pixel cells 120R, a plurality of green pixel cells 120G, and a plurality of blue pixel cells 120B. In some embodiments, a plurality of first isolation members 23X extending along a second direction D2 and a plurality of second isolation members 23Y extending along a third direction D3 are disposed in each of the red pixel cells 120R, the green pixel cells 120G, and the blue pixel cells 120B. The first isolation members 23X and the second isolation members 23Y may be arranged alternately. In some embodiments, each of the red pixel cells 120R, the green pixel cells 120G, and the blue pixel cells 120B includes 50% of the first isolation members 23X and 50% of the second isolation members 23Y. That is, half of the partition members in each pixel unit are rotated 90 degrees, and the other half of the partition members are not rotated.

[0075] Figure 18A for Figure 17 FIG. 1 is an enlarged view of portion R120 of image sensing structure 140 . Figure 18B and Figure 18C for Figure 18A Schematic cross-sectional view and perspective view of part R120. Figure 18A Portion R120 is a red pixel unit 120R, which includes four adjacent red pixel regions 20R separated by two perpendicular isolation structures 21. In some embodiments, red pixel unit 120R includes two first isolation members 23X extending along a second direction D2 and two second isolation members 23Y extending along a third direction D3. In some embodiments, the two first isolation members 23X are connected to the same isolation structure 21, and the two second isolation members 23Y are connected to another isolation structure 21.

[0076] from Figure 18A As can be seen from the top view, the two first isolation members 23X are diagonally opposite to each other, and the two second isolation members 23Y are diagonally opposite to each other. Figure 18A As shown, in the upper left red pixel region 20R or the lower right red pixel region 20R, the two photodiode regions 22R are separated from each other by the DTI 23Y in the pixel. That is, the two photodiode regions 22R are arranged along the first direction D1. Figure 18A As shown, in the upper right red pixel region 20R or the lower left red pixel region 20R, two photodiode regions 22R are separated from each other by the first isolation member 23X. That is, the paired photodiode regions 22R are arranged along the second direction D2. Figure 18B and Figure 18C It is shown that the first isolation member 23X, the second isolation member 23Y, and the isolation structure 21 are embedded in the substrate 10 and extend along a specific direction in the substrate 10 .

[0077] Figure 19A and Figure 19B yes Figure 17 Schematic cross-sectional view and perspective view of a portion R130 of the image sensing structure 140. Figure 17 、 Figure 19A and Figure 19B Portion R130 includes a red pixel region 20R, two green pixel regions 20G, and a blue pixel region 20B, adjacent to each other and separated by two perpendicular isolation structures 21. Portion R130 includes a first isolation member 23X located in red pixel region 20R, a first isolation member 23X located in blue pixel region 20B, and two first isolation members 23X located in green pixel region 20G. First isolation member 23X, second isolation member 23Y, and isolation structures 21 are embedded in substrate 10 and extend along a specific direction within substrate 10.

[0078] In the image sensing structure 140, the two green pixel regions 20G in each green pixel unit 120G receive the red light beam from the adjacent red pixel region 20R. Figure 17 As shown by the arrows in the middle, all green pixel units 120G have substantially the same average brightness, thereby improving the brightness uniformity of the pixels of the image sensing structure 140.

[0079] Figure 20 FIG. 1 is a flow chart illustrating a method 200 of forming an image sensing structure 110 . Figures 21 to 27 To show Figure 20 Schematic cross-sectional or top view of sequential operations of method 200. Operations 201, 203, 205, 207, 209, and 211 are used to form a pixel portion P2 connected to a circuit portion P3.

[0080] In order to form the pixel portion P2, Figure 20 In operation 201, a substrate 10 is provided, such as Figure 21 As shown. The substrate 10 has a first surface S1 (or front side S1) and a second surface S2 (or back side S2) opposite the first surface S1. The substrate 10 includes any type of semiconductor body, such as a silicon (Si) wafer, a silicon germanium (SiGe) wafer, a silicon-on-insulator (SOI) substrate, etc. Although not shown, the substrate 10 includes one or more semiconductor layers and / or epitaxial layers formed thereon. In some embodiments, the substrate 10 is doped with p-type impurities and thus forms a p-type substrate.

[0081] exist Figure 20 In operation 203, a transistor T10 is formed on the first surface S1 of the substrate 10, as shown in FIG. Figure 22 As shown. The transistor T10 includes a gate structure and a source / drain structure, which can be formed using an appropriate method, such as lithography, etching, epitaxy, implantation, or deposition. In some embodiments, the transistor T10 includes a transfer transistor used as a transfer gate, a reset transistor used as a reset gate, a source follower transistor used as a source follower gate (amplification gate), and a select transistor used as a select gate. In some embodiments, a floating node (or floating diffusion region) 14 is formed within the substrate 10 and near the first surface S1. The floating node 14 is formed as a high implant (e.g., an N+ implant) in the substrate 10. The floating node 14 is electrically connected to the source follower transistor and / or the select transistor.

[0082] exist Figure 20 In operation 205, a circuit portion P3 (or interconnection portion P3) is formed on the first surface S1 of the substrate 10, as shown in FIG. Figure 23 As shown. Circuit portion P3 includes one or more interlayer dielectric (ILD) layers 42 and a plurality of conductors 44. Circuit portion P3 can be formed using a suitable method, such as photolithography, etching, deposition, electroplating or planarization. ILD layer 42 can be formed of oxide or other suitable materials. ILD layer 42 can be formed of one or more of a low-k dielectric layer (i.e., a dielectric material having a dielectric constant less than about 3.9), an ultra-low-k dielectric layer or an oxide (e.g., silicon oxide). Conductor 44 can be formed of copper (Cu), cobalt (Co), aluminum (Al), silver (Ag), gold (Au), tungsten (W), etc. or a combination thereof. Conductor 44 is interconnected and embedded in ILD layer 42 through conductive vias (not shown). Transistor T10 is covered and surrounded by ILD layer 42. Circuit portion P3 is electrically connected to transistor T10.

[0083] exist Figure 20 In operation 207, a plurality of isolation structures 21 are formed in the substrate 10, such as Figure 24A and Figure 24B Reference Figure 24A , turn the substrate 10 over so that the second surface S2 faces upward. Figure 24B Although not specifically shown, a plurality of trenches extending from the second surface S2 of the substrate 10 to a predetermined depth of the substrate 10 are formed using a photolithography or etching operation. The trenches are filled with a dielectric material using a deposition operation. The dielectric material includes, for example, silicon oxide (SiO), silicon nitride (SiN), aluminum oxide (AlO), tantalum oxide (TaO), hafnium oxide (HfO), hafnium silicon oxide (HfSiO), hafnium aluminum oxide (HfAlO), hafnium tantalum oxide (HfTaO), or a combination thereof.

[0084] exist Figure 20 In operation 209, a plurality of pixel regions 20 are formed in the substrate 10, such as Figure 25A and Figure 25B Reference Figure 25A , an implantation operation is used to dope n-type impurities 18 into the substrate 10. Figure 25B , substrate 10 is doped with n-type impurities 18 to form pixel regions 20. Pixel regions 20 include a PN junction formed between undoped substrate 10 (which is p-type) and doped substrate 10 (which is n-type). The PN junction can form a photodiode. Pixel regions 20 are separated by isolation structures 21.

[0085] exist Figure 20 In operation 211, a plurality of first isolation members 23X and second isolation members 23Y are formed in the substrate 10, as shown in FIG. Figures 26A to 26E Reference Figure 26A A photoresist pattern 40 is formed on the substrate 10 using a photomask. The photoresist pattern 40 includes a plurality of openings O1 that expose portions of the second surface S2 corresponding to the pixel region 20.

[0086] See also Figure 26B , Figure 26B for Figure 26A Schematic top view of FIG. In some embodiments, the opening O1 has a strip shape. In some embodiments, the opening O1 includes a first opening O1X extending along the second direction D2 and a second opening O1Y extending along the third direction D3. In some embodiments, the first opening O1X is substantially perpendicular to the second opening O1Y.

[0087] refer to Figure 26C , using the photoresist pattern 40 as an etching mask, an etching operation is used to remove portions of the substrate 10. The photoresist pattern 40 is then removed. As a result, a plurality of trenches O2 are formed in the substrate 10. The trenches O2 extend from the second surface S2 of the substrate 10 to a predetermined depth of the substrate 10.

[0088] refer to Figure 26D A deposition operation is used to deposit a dielectric material into trench O2. The dielectric material includes, for example, silicon oxide (SiO), silicon nitride (SiN), aluminum oxide (AlO), tantalum oxide (TaO), hafnium oxide (HfO), hafnium silicon oxide (HfSiO), hafnium aluminum oxide (HfAlO), hafnium tantalum oxide (HaTaO), or a combination thereof. A planarization operation can be used to remove excess dielectric material. Thus, an isolation member 23 is formed in substrate 10. Isolation member 23 has a top surface that is coplanar with second surface S2 of substrate 10 or isolation structure 21.

[0089] refer to Figure 26E , Figure 26E for Figure 26D Schematic top view of the structure. In some embodiments, the isolation member 23 has a strip shape. In some embodiments, the isolation member 23 includes a first isolation member 23X extending along the second direction D2 and a second isolation member 23Y extending along the third direction D3. In some embodiments, the first isolation member 23X and the second isolation member 23Y are connected to the isolation structure 21. Thus, the formation of the pixel portion P2 and the circuit portion P3 is completed.

[0090] exist Figure 20 In operation 213, an optical portion P1 is formed on the second surface S2 of the substrate 10, as shown in FIG. Figure 27 As shown. In some embodiments, the optical portion P1 includes an anti-reflection layer 24, a plurality of metal grids 25, one or more dielectric layers 26, a plurality of color filters 27, and a plurality of microlenses 28. The anti-reflection layer 24 is formed on the second surface S2 of the substrate 10. In some embodiments, the anti-reflection layer 24 is formed of an oxide, a nitride, a high-k dielectric material, such as aluminum oxide (AlO), tantalum oxide (TaO), hafnium oxide (HfO), hafnium silicon oxide (HfSiO), hafnium aluminum oxide (HfAlO), hafnium tantalum oxide (HfTaO), or a combination thereof. The anti-reflection layer 24 can minimize light reflection and thus allow more light to reach the pixel region 20.

[0091] In some embodiments, a metal grid 25 is formed on the anti-reflective layer 24 and is aligned with each of the isolation structures 21. The metal grid 25 can be formed of tungsten (W), copper (Cu), or aluminum copper (AlCu). The metal grid 25 can be used to reduce optical interference between one pixel region 20 and an adjacent pixel region 20.

[0092] Color filters 27 are formed on the anti-reflection layer 24 and are adjacent to the metal grid 25. Adjacent color filters 27 are separated by one metal grid 25. The space above the metal grid 25 can be filled with a dielectric layer 26 made of oxide. The color filters 27 are separated from the substrate 10 or the pixel region 20 by the anti-reflection layer 24.

[0093] In some embodiments, each color filter 27 is aligned with a corresponding pixel area 20. The color filter 27 is formed above the two photodiode regions 22 and the isolation member 23 between the two photodiode regions 22. Such an arrangement can increase the radiation of incident light onto the pixel area 20. The color filter 27 is used to allow light or radiation having a wavelength within a specific range to pass through. For example, the color filter 27 for transmitting incident light with a wavelength between about 620 nanometers (nm) and about 750 nm (i.e., red light) is referred to as a red filter 27R. The color filter 27 for transmitting incident light with a wavelength between about 495 nm and about 570 nm (i.e., green light) is referred to as a green filter 27G. The color filter 27 for transmitting incident light with a wavelength between about 450 nm and about 495 nm (i.e., blue light) is referred to as a blue filter 27B.

[0094] In some embodiments, microlenses 28 are formed on portions of color filter 27 and dielectric layer 26. Microlenses 28 have curved surfaces (or convex surfaces) that guide incident light and promote convergence of the incident light. Microlenses 28 are aligned with color filter 27 and pixel region 20. This arrangement can increase the radiation of incident light on pixel region 20. Since paired photodiode regions 22 are formed in a single pixel region 20, color filter 27 is formed above the two photodiode regions 22, and microlenses 28 are formed above the two photodiode regions 22. As a result, the formation of image sensing structure 110 is completed.

[0095] Figure 28 Schematic diagram of a combination of two image sensing structures 150 and 160. In some embodiments, image sensing structure 150 is part of an image sensing device formed on a first wafer, and image sensing structure 160 is part of an image sensing device formed on a second wafer. In some embodiments, image sensing structure 150 includes a plurality of first isolation members 23X and second isolation members 23Y. For example, first isolation members 23X may be provided in red pixel units 120R and blue pixel units 120B, but the present disclosure is not limited thereto. In some embodiments, image sensing structure 160 includes a plurality of second isolation members 23Y. Compared to image sensing structure 160, half of the second isolation members 23Y in image sensing structure 150 are rotated 90 degrees to form first isolation members 23X.

[0096] In some embodiments, the image sensing structure 150 includes a plurality of first transistors T12 arranged symmetrically with respect to one another. The first transistors T12 include transfer (TX) transistors or transfer gates. In some embodiments, the first transistors T12 are disposed below and on both sides of a first isolation member 23X. In some embodiments, the first transistors T12 are disposed below and on both sides of a second isolation member 23Y. In some embodiments, the image sensing structure 160 includes a plurality of second transistors T14 disposed adjacent to the second isolation member 23Y. The second transistors T14 may be arranged parallel to the extension direction of the second isolation member 23Y. The second transistors T14 may include a reset (RST) transistor, a source follower (SF) transistor, a row select (SEL) transistor, and the like. In some embodiments, the image sensing structure 150 is aligned with and bonded to the image sensing structure 160. In such embodiments, the first transistors T12 may be electrically connected to the second transistors T14. This design simplifies the transistor layout and wiring of the image sensing structure. Furthermore, it can also address the issue of uneven pixel brightness.

[0097] One aspect of the present disclosure provides an image sensing structure. The image sensing structure includes: a first pixel, the first pixel including a first photodiode, a second photodiode, and a first isolation member, the first isolation member being disposed between the first photodiode and the second photodiode and extending along a first direction; and a second pixel, the second pixel being disposed adjacent to the first pixel and including a third photodiode, a fourth photodiode, and a second isolation member, the second isolation member being disposed between the third photodiode and the fourth photodiode and extending along a second direction substantially perpendicular to the first direction.

[0098] One aspect of the present disclosure provides another image sensing structure. The image sensing structure includes: a first sensing member, the first sensing member including a plurality of first pixels adjacent to and separated from each other, wherein each of the plurality of first pixels includes a first photodiode, a second photodiode, and a first isolation member disposed between the first and second photodiodes; and a second sensing member, the second sensing member being adjacent to the first sensing member and including a plurality of second pixels adjacent to and separated from each other, wherein each of the plurality of second pixels includes a third photodiode, a fourth photodiode, and a second isolation member disposed between the third and fourth photodiodes, wherein at least one of the first isolation members extends along a first direction, and at least one of the second isolation members extends along a second direction substantially perpendicular to the first direction.

[0099] Another aspect of the present disclosure provides a method for forming an image sensing structure. The method includes providing a substrate having a first surface and a second surface opposite the first surface; forming a first photodiode and a second photodiode in the substrate; forming a third photodiode and a fourth photodiode in the substrate; forming a first isolation member, the first isolation member extending within the substrate between the first photodiode and the second photodiode; and forming a second isolation member adjacent to the first isolation member, the second isolation member extending within the substrate between the third photodiode and the fourth photodiode, wherein the first isolation member extends along a first direction and the second isolation member extends along a second direction substantially perpendicular to the first direction.

[0100] Some embodiments of the present application provide an image sensing structure, including: a first pixel, including a first photodiode, a second photodiode and a first isolation member, the first isolation member being arranged between the first photodiode and the second photodiode and extending along a first direction; and a second pixel, arranged to be adjacent to the first pixel and including a third photodiode, a fourth photodiode and a second isolation member, the second isolation member being arranged between the third photodiode and the fourth photodiode and extending along a second direction substantially perpendicular to the first direction.

[0101] In some embodiments, the first pixel includes a first color filter disposed over the first photodiode, the second photodiode, and the first isolation member, and the second pixel includes a second color filter disposed over the third photodiode, the fourth photodiode, and the second isolation member. In some embodiments, the first color filter is a red filter, and the second color filter is a green filter or a blue filter. In some embodiments, the first color filter is a red filter or a blue filter, and the second color filter is a green filter. In some embodiments, the first color filter and the second color filter are red filters. In some embodiments, the image sensing structure further includes a third isolation member disposed between the first pixel and the second pixel and extending along the second direction. In some embodiments, the third isolation member is disposed between the first photodiode and the third photodiode, and between the first photodiode and the fourth photodiode. In some embodiments, the thickness of the first isolation member and the thickness of the second isolation member are each less than the thickness of the third isolation member. In some embodiments, a second image sensing structure is bonded to the image sensing structure, the image sensing structure including a first transistor, and the second image sensing structure including a second transistor electrically connected to the first transistor. In some embodiments, the first transistor comprises a pass transistor, and the second transistor comprises a reset transistor, a source follower transistor, or a row select transistor.

[0102] Other embodiments of the present application provide an image sensing structure, including: a first sensing member, including a plurality of first pixels adjacent to and separated from each other, wherein each of the plurality of first pixels includes a first photodiode, a second photodiode and a first isolation member, and the first isolation member is arranged between the first photodiode and the second photodiode; and a second sensing member, adjacent to the first sensing member, and including a plurality of second pixels adjacent to and separated from each other, wherein each of the plurality of second pixels includes a third photodiode, a fourth photodiode and a second isolation member, and the second isolation member is arranged between the third photodiode and the fourth photodiode, wherein at least one of the first isolation members extends along a first direction, and at least one of the second isolation members extends along a second direction substantially perpendicular to the first direction.

[0103] In some embodiments, all first isolation members extend along the first direction, and all second isolation members extend along the second direction. In some embodiments, each of the plurality of first pixels is a red pixel, and each of the plurality of second pixels is a green pixel or a blue pixel. In some embodiments, each of the plurality of first pixels is a red pixel or a blue pixel, and each of the plurality of second pixels is a green pixel. In some embodiments, the plurality of first pixels includes a first red pixel, a first green pixel, and a first blue pixel, and the plurality of second pixels includes a second red pixel, a second green pixel, and a second blue pixel.

[0104] Some other embodiments of the present application provide a method for forming an image sensing structure, comprising: providing a substrate having a first surface and a second surface opposite to the first surface; forming a first photodiode and a second photodiode in the substrate; forming a third photodiode and a fourth photodiode in the substrate; forming a first isolation member, the first isolation member being within the substrate and extending between the first photodiode and the second photodiode; and forming a second isolation member adjacent to the first isolation member, and the second isolation member being within the substrate and extending between the third photodiode and the fourth photodiode, wherein the first isolation member extends along a first direction and the second isolation member extends along a second direction substantially perpendicular to the first direction.

[0105] In some embodiments, the first photodiode and the second photodiode extend along the first direction, and the third photodiode and the fourth photodiode extend along the second direction, and the first photodiode, the second photodiode, the third photodiode, and the fourth photodiode are formed by an ion implantation operation. In some embodiments, the formation of the first photodiode and the second photodiode and the formation of the third photodiode and the fourth photodiode are performed before the formation of the first isolation member and before the formation of the second isolation member. In some embodiments, the formation of the first isolation member includes removing a first portion of the substrate from the first surface toward the second surface to form a first trench, and filling the first trench with a dielectric material, and the formation of the second isolation member includes removing a second portion of the substrate from the first surface toward the second surface to form a second trench, and filling the second trench with the dielectric material. In some embodiments, the first trench is substantially perpendicular to the second trench.

[0106] The features of several embodiments have been summarized above so that those skilled in the art can better understand aspects of the present disclosure. Those skilled in the art will appreciate that they can easily use this disclosure as a basis to design or modify other operations and structures for implementing the same purposes and / or achieving the same advantages as the embodiments described herein. Those skilled in the art will also appreciate 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 modifications herein without departing from the spirit and scope of the present disclosure.

[0107] Furthermore, the scope of this application is not intended to be limited to the particular embodiments of the processes, machines, manufactures, compositions of matter, means, methods, and steps described in the specification. A person of ordinary skill in the art will readily understand from the disclosure of this application that, in accordance with this application, processes, machines, manufactures, compositions of matter, means, methods, or steps currently existing or later developed that perform substantially the same functions or achieve substantially the same results as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufactures, compositions of matter, means, methods, or steps.

Claims

1. An image sensing structure, comprising: a first pixel comprising a first photodiode, a second photodiode, and a first isolation member, wherein the first isolation member is disposed between the first photodiode and the second photodiode and extends along a first direction; as well as A second pixel is disposed adjacent to the first pixel and includes a third photodiode, a fourth photodiode, and a second isolation member disposed between the third photodiode and the fourth photodiode and extending in a second direction substantially perpendicular to the first direction.

2. The image sensing structure according to claim 1, wherein: The first pixel includes a first color filter disposed over the first photodiode, the second photodiode, and the first isolation member, and the second pixel includes a second color filter disposed over the third photodiode, the fourth photodiode, and the second isolation member.

3. The image sensing structure according to claim 2, wherein: The first color filter is a red filter, and the second color filter is a green filter or a blue filter.

4. The image sensing structure according to claim 2, wherein: The first color filter is a red filter or a blue filter, and the second color filter is a green filter.

5. The image sensing structure according to claim 2, wherein: The first color filter and the second color filter are red filters. 6 . The image sensing structure according to claim 1 , further comprising a third isolation member disposed between the first pixel and the second pixel and extending along the second direction.

7. The image sensing structure according to claim 6, wherein: The third isolation member is disposed between the first photodiode and the third photodiode, and between the first photodiode and the fourth photodiode.

8. The image sensing structure according to claim 6, wherein: The thickness of the first isolation member and the thickness of the second isolation member are respectively smaller than the thickness of the third isolation member.

9. An image sensing structure comprising: a first sensing member comprising a plurality of first pixels adjacent to and spaced apart from each other, wherein each of the plurality of first pixels comprises a first photodiode, a second photodiode, and a first isolation member disposed between the first photodiode and the second photodiode; and a second sensing member adjacent to the first sensing member and comprising a plurality of second pixels adjacent to and spaced apart from each other, wherein each of the plurality of second pixels comprises a third photodiode, a fourth photodiode, and a second isolation member, the second isolation member being disposed between the third photodiode and the fourth photodiode; At least one of the first isolation members extends along a first direction, and at least one of the second isolation members extends along a second direction substantially perpendicular to the first direction.

10. A method of forming an image sensing structure, comprising: providing a substrate having a first surface and a second surface opposite to the first surface; forming a first photodiode and a second photodiode in the substrate; forming a third photodiode and a fourth photodiode in the substrate; forming a first isolation member within the substrate and extending between the first photodiode and the second photodiode; as well as forming a second isolation member adjacent to the first isolation member and extending within the substrate and between the third photodiode and the fourth photodiode, The first isolation member extends along a first direction, and the second isolation member extends along a second direction substantially perpendicular to the first direction.

Images