Solid-state imaging device

Abstract

The disclosed embodiment provides a solid-state imaging device having a first area and a second area surrounding the first area. The solid-state imaging device includes a substrate having a plurality of photoelectric conversion elements. The solid-state imaging device also includes a color filter layer, which is disposed on the substrate. The color filter layer includes a plurality of color filter segments, and the color filter segments correspond to the photoelectric conversion elements. The solid-state imaging device also includes an optical waveguide layer, which is disposed above the color filter layer. The optical waveguide layer includes a waveguide separation grid, a waveguide material in the gap of the waveguide separation grid, and an anti-reflection film on the waveguide separation grid and the waveguide material. The width of the top of the waveguide separation grid is greater than the width of the bottom of the waveguide separation grid.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to an imaging device, and more particularly to a solid-state imaging device including a waveguide partitioning grid, wherein the waveguide partitioning grid has a variable width. Background Art

[0002] Solid-state imaging devices, such as charge-coupled device (CCD) imaging devices, complementary metal-oxide semiconductor (CMOS) imaging devices, etc., have been widely used in various image capturing devices, such as digital still cameras, digital video cameras, and similar devices. In these solid-state imaging devices, a light sensing portion is formed at each of a plurality of pixels, and a signal charge can be generated according to the amount of light received in the light sensing portion. In addition, the signal charge generated in the light sensing portion can be transmitted and amplified to obtain an image signal.

[0003] In recent years, in order to increase the number of pixels to provide high-resolution images, the trend of solid-state imaging devices, especially complementary metal oxide semiconductor (CMOS) imaging devices, is to reduce the pixel size. However, as the pixel size continues to decrease, various challenges still exist in the design and manufacture of solid-state imaging devices. Summary of the invention

[0004] An object of the embodiments of the present disclosure is to provide a solid-state imaging device to solve at least one of the above problems.

[0005] In an edge region or a peripheral region (or vicinity) of a solid-state imaging device, incident light radiated into the solid-state imaging device may be inclined, and the sensitivity of the photoelectric conversion element may be non-uniform due to the different refractive indices of different color filter segments. In an embodiment of the present disclosure, the solid-state imaging device includes a waveguide separation grid having different grid widths, which can improve the uniformity of pixel sensitivity in an edge region or a peripheral region of the solid-state imaging device.

[0006] According to some embodiments of the present disclosure, a solid-state imaging device is provided, which has a first area and a second area surrounding the first area. The solid-state imaging device includes a substrate having a plurality of photoelectric conversion elements. The solid-state imaging device also includes a color filter layer, which is disposed on the substrate. The color filter layer includes a plurality of color filter segments, and the color filter segments correspond to the photoelectric conversion elements. The solid-state imaging device also includes an optical waveguide layer, which is disposed above the color filter layer. The optical waveguide layer includes a waveguide separation grid, a waveguide material in the gap of the waveguide separation grid, and an anti-reflection film on the waveguide separation grid and the waveguide material. The width of the top of the waveguide separation grid is greater than the width of the bottom of the waveguide separation grid.

[0007] The beneficial effect of the embodiments of the present disclosure is that by adjusting the width of some components in the solid-state imaging device, the difference in sensitivity between color filter segments can be reduced, thereby improving the uniformity of sensitivity in (or near) the edge or peripheral area of ​​the solid-state imaging device. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The following will be described in detail with reference to the accompanying drawings. It should be noted that the various characteristic components are not drawn to scale and are only used for illustration. In fact, the size of the components may be enlarged or reduced to clearly show the technical features of the embodiments of the present disclosure.

[0009] Figure 1 A top view of a solid-state imaging device according to an embodiment of the present disclosure is shown.

[0010] Figure 2A A partial plan view of a region ROI- 1 of a solid-state imaging device according to some embodiments of the present disclosure is shown.

[0011] Figure 2B A partial plan view of a region ROI-2 of a solid-state imaging device according to some embodiments of the present disclosure is shown.

[0012] Figure 2C A partial plan view of a region ROI- 3 of a solid-state imaging device according to some embodiments of the present disclosure is shown.

[0013] Figure 3A A partial cross-sectional view of a region ROI- 1 of a solid-state imaging device according to some embodiments of the present disclosure is shown.

[0014] Figure 3B A partial cross-sectional view of a region ROI-2 of a solid-state imaging device according to some embodiments of the present disclosure is shown.

[0015] Figure 3C A partial cross-sectional view of a region ROI- 3 of a solid-state imaging device according to some embodiments of the present disclosure is shown.

[0016] Figure 4A A partial cross-sectional view of a region ROI- 1 of a solid-state imaging device according to some embodiments of the present disclosure is shown.

[0017] Figure 4B A partial cross-sectional view of a region ROI- 3 of a solid-state imaging device according to some embodiments of the present disclosure is shown.

[0018] Figure 5A A partial cross-sectional view of a region ROI- 1 of a solid-state imaging device according to some embodiments of the present disclosure is shown.

[0019] Figure 5B A partial cross-sectional view of a region ROI- 3 of a solid-state imaging device according to some embodiments of the present disclosure is shown.

[0020] Fig. 6A A partial cross-sectional view of a region ROI- 1 of a solid-state imaging device according to some embodiments of the present disclosure is shown.

[0021] Figure 6B A partial cross-sectional view of a region ROI- 3 of a solid-state imaging device according to some embodiments of the present disclosure is shown.

[0022] Fig. 7A A partial cross-sectional view of a region ROI- 1 of a solid-state imaging device according to some embodiments of the present disclosure is shown.

[0023] Figure 7B A partial cross-sectional view of a region ROI- 3 of a solid-state imaging device according to some embodiments of the present disclosure is shown.

[0024] Fig. 8A A partial cross-sectional view of a solid-state imaging device according to some embodiments of the present disclosure is shown.

[0025] Figure 8B A partial cross-sectional view of a solid-state imaging device according to some embodiments of the present disclosure is shown.

[0026] The reference numerals are as follows:

[0027] 100,200,300,400,500,600,700,800: Solid-state imaging device

[0028] 101:Substrate

[0029] 101B: Back surface

[0030] 101F: Front surface

[0031] 103: Photoelectric conversion element

[0032] 105: Wiring layer

[0033] 107: High dielectric constant film

[0034] 109: Buffer layer

[0035] 111:Metal Grid

[0036] 111A: First metal part

[0037] 111B: Second metal part

[0038] 113B: Color filter separator grid

[0039] 113B1: First color part

[0040] 113B2: Second color part

[0041] 115: Color filter section

[0042] 115GB: Green / Blue filter segment

[0043] 115R: Red filter segment

[0044] 120: Color filter layer

[0045] 121: Waveguide Materials

[0046] 121GB: Top surface

[0047] 121R: Top surface

[0048] 123A: Waveguide Separator Grid

[0049] 123A1: First waveguide section

[0050] 123A2, 123A2': Second waveguide section

[0051] 123A3: The third waveguide section

[0052] 123B: Anti-reflective film

[0053] 130: Optical waveguide layer

[0054] A-A',B-B',C-C',D-D',E-E',F-F': Section Line

[0055] CW: Grid Width

[0056] CW1: First color width

[0057] CW2: Second color width

[0058] D: Direction

[0059] MW1: First metal width

[0060] MW2: Second metal width

[0061] P: Regular pixel

[0062] P1: Additional regular pixels

[0063] PDAF: Autofocus Pixel

[0064] ROI-1, ROI-2, ROI-3: area

[0065] WW1: First waveguide width

[0066] WW2, WW2': Second waveguide width

[0067] WW3: Third waveguide width DETAILED DESCRIPTION

[0068] The following disclosure provides many different embodiments or examples to implement the different features of the present invention. The following disclosure describes specific examples of various components and their arrangement to simplify the description. Of course, these specific examples are not intended to be limiting. For example, if the present disclosure describes an embodiment in which a first characteristic component is formed on or above a second characteristic component, it means that it may include an embodiment in which the first characteristic component and the second characteristic component are in direct contact, and may also include an embodiment in which an additional characteristic component is formed between the first characteristic component and the second characteristic component, so that the first characteristic component and the second characteristic component may not be in direct contact.

[0069] It should be understood that additional operating steps may be implemented before, during or after the method, and in other embodiments of the method, some operating steps may be replaced or omitted.

[0070] In addition, spatially related terms may be used, such as "below", "below", "lower", "above", "above", "higher" and similar terms. These spatially related terms are used to facilitate the description of the relationship between one (some) elements or features and another (some) elements or features in the drawings. These spatially related terms include different orientations of the device in use or operation, as well as the orientations described in the drawings. When the device is turned to a different orientation (rotated 90 degrees or other orientations), the spatially related adjectives used therein will also be interpreted according to the turned orientation.

[0071] In the specification, the terms "about", "approximately" and "generally" generally mean within 20%, within 10%, within 5%, within 3%, within 2%, within 1%, or within 0.5% of a given value or range. The numbers given here are approximate numbers, that is, in the absence of specific description of "about", "approximately" and "generally", the meanings of "about", "approximately" and "generally" can still be implied.

[0072] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meanings as those commonly understood by those skilled in the art to which this disclosure belongs. It is understood that these terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with the background or context of the relevant technology and the present disclosure, and should not be interpreted in an idealized or overly formal manner unless specifically defined in the embodiments of the present disclosure.

[0073] The different embodiments disclosed below may repeatedly use the same reference symbols and / or marks. These repetitions are for the purpose of simplicity and clarity, and are not intended to limit the specific relationship between the different embodiments and / or structures discussed.

[0074] In a solid-state imaging device, incident light is irradiated onto the edge (peripheral area) of a pixel array at an oblique angle, which is greater than the normal angle of the incident light irradiated onto the central area (central area) of the pixel array. The angle of the incident light is determined by the deviation from the normal of the light receiving surface of the solid-state imaging device. For example, the oblique angle of the incident light irradiated onto the edge (peripheral area) of the pixel array is generally about + / -20 degrees to about + / -40 degrees, and the normal angle of the incident light irradiated onto the central area of ​​the pixel array is about 0 degrees.

[0075] Solid-state imaging devices can be roughly divided into two types according to the direction in which light is incident on the light receiving unit. One is a front-side illuminated (FSI) imaging device, which receives light incident on the front side of the substrate, and a wiring layer of a reading circuit is formed on the front side of the substrate. The other is a back-side illuminated (BSI) imaging device, which receives light incident on the back side of the substrate, and no wiring layer is formed on the back side of the substrate. In order to image a color image, a color filter is provided in the FSI and BSI imaging devices. FSI and BSI imaging devices usually have a light-shielding grid structure, which is used to block light between pixels to prevent color mixing.

[0076] Figure 1 A top view of a solid-state imaging device 100 according to an embodiment of the present disclosure is shown. Figure 1 , region ROI-1 represents the central region of the solid-state imaging device 100, region ROI-3 represents the edge region (peripheral region) of the solid-state imaging device 100, and region ROI-2 represents the region between region ROI-1 and region ROI-3. Figure 1 1 and 2 show relative positions of the region ROI-1, region ROI-2, and region ROI-3 of the solid-state imaging device 100. Note that the relative positions of the region ROI-1, region ROI-2, and region ROI-3 may also be applied in the following drawings.

[0077] Figure 2A A partial plan view of a region ROI- 1 of the solid-state imaging device 200 according to some embodiments of the present disclosure is shown. Figure 2B A partial plan view of a region ROI- 2 of the solid-state imaging device 200 according to some embodiments of the present disclosure is shown. Figure 2C A partial plan view of a region ROI- 3 of the solid-state imaging device 200 according to some embodiments of the present disclosure is shown. Figure 3A A partial cross-sectional view of a region ROI- 1 of a solid-state imaging device 200 according to some embodiments of the present disclosure is shown. Figure 3B A partial cross-sectional view of a region ROI- 2 of a solid-state imaging device 200 according to some embodiments of the present disclosure is shown. Figure 3C A partial cross-sectional view of a region ROI- 3 of the solid-state imaging device 200 according to some embodiments of the present disclosure is shown.

[0078] In this embodiment, Figure 3A Can be along Figure 2A A cross-sectional view of the region ROI-1 of the solid-state imaging device 200 cut along the AA' section line or the BB' section line. Similarly, Figure 3B Can be along Figure 2B The cross-sectional view of the region ROI-2 of the solid-state imaging device 200 cut along the CC' section line or the DD' section line, and Figure 3C Can be along Figure 2C A cross-sectional view of a region ROI-3 of the solid-state imaging device 200 cut along the EE' section line or the FF' section line. Figures 2A to 3C The relative positions of ROI-1, ROI-2 and ROI-3 in the Figure 1 It should be noted that for the sake of brevity, Figures 2A to 3C Some components of the solid-state imaging device 200 may be omitted.

[0079] In some embodiments, the solid-state imaging device 200 may be formed by a complementary metal oxide semiconductor (CMOS) imaging device or a charge coupled device (CCD) imaging device, but the embodiments of the present disclosure are not limited thereto. Figure 3A and Figure 3C As shown, the solid-state imaging device 200 includes a substrate 101, such as a wafer or a chip, but the embodiments of the present disclosure are not limited thereto. The substrate 101 has a front surface 101F and a back surface 101B opposite to the front surface 101F. A plurality of photoelectric conversion elements 103 (e.g., photodiodes) may be formed in the substrate 101.

[0080] Reference FIG. 3A to FIG. 3C , the substrate 101 has a plurality of photoelectric conversion elements 103. The photoelectric conversion elements 103 in the substrate 101 are isolated from each other via an isolation structure (not shown), and the isolation structure is, for example, a shallow trench isolation (STI) region or a deep trench isolation (DTI) region. An etching process can be used to form a trench in the substrate 101, and the trench is filled with an insulating or dielectric material to form an isolation structure. Although the drawings of the solid-state imaging device 200 of the embodiment only show a few pixels, in fact, the solid-state imaging device 200 has millions or more pixels in the pixel array.

[0081] In some embodiments, the photoelectric conversion element 103 is formed on the back surface 101B of the substrate 101, and the wiring layer 105 is formed on the front surface 101F of the substrate 101, but the embodiments of the present disclosure are not limited thereto. The wiring layer 105 may be an internal connection structure including a plurality of wires and vias buried in a plurality of dielectric layers, and the wiring layer 105 may further include various circuits required by the solid-state imaging device 200. Incident light may be irradiated to the side of the back surface 101B and received by the photoelectric conversion element 103. FIG. 3A to FIG. 3C The solid-state imaging device 200 shown may be referred to as a back-illuminated (BSI) imaging device, but the embodiments of the present disclosure are not limited thereto. In some other embodiments, the solid-state imaging device 200 may be a front-illuminated (FSI) imaging device. For an FSI imaging device, FIG. 3A to FIG. 3C The illustrated substrate 101 and wiring layer 105 may be turned upside down. In the FSI imaging device, incident light is irradiated to the side of the front surface 101F, passes through the wiring layer 105, and is then received by the photoelectric conversion element 103 formed on the back surface 101B of the substrate 101.

[0082] like FIG. 3A to FIG. 3CAs shown, in some embodiments, the solid-state imaging device 200 may also include a high dielectric constant (high-κ) film 107 formed on the back surface 101B of the substrate 101 and covering the photoelectric conversion element 103. The material of the high dielectric constant film 107 may include hafnium oxide (HfO2), hafnium tantalum oxide (HfTaO), hafnium titanium oxide (HfTiO), hafnium zirconium oxide (HfZrO), tantalum pentoxide (Ta2O5), other suitable high dielectric constant (high-κ) materials or combinations thereof, but the embodiments of the present disclosure are not limited thereto. The high dielectric constant film 107 may be formed by a deposition process. The deposition process is, for example, chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD) or other deposition techniques. The high dielectric constant film 107 may have a high refractive index and light absorption capability.

[0083] In some embodiments, the solid-state imaging device 200 may further include a buffer layer 109 formed on the high dielectric constant film 107. The material of the buffer layer 109 may include silicon oxide, silicon nitride, silicon oxynitride, other suitable insulating materials or combinations thereof, but the embodiments of the present disclosure are not limited thereto. The buffer layer 109 may be formed by a deposition process. The deposition process may be, for example, spin coating, chemical vapor deposition, flowable chemical vapor deposition (FCVD), plasma enhanced chemical vapor deposition, physical vapor deposition (PVD) or other deposition techniques.

[0084] Reference FIG. 3A to FIG. 3C The solid-state imaging device 200 also includes a color filter layer 120 disposed on the substrate 101 and located above the photoelectric conversion element 103. In more detail, FIG. 3A to FIG. 3C As shown, the color filter layer 120 includes a metal grid 111 formed on the buffer layer 109, but the embodiment of the present disclosure is not limited thereto. In some embodiments, the material of the metal grid 111 may include tungsten (W), aluminum (Al), metal nitride (e.g., titanium nitride (TiN)), other suitable materials or combinations thereof, but the embodiment of the present disclosure is not limited thereto. The metal grid 111 may be formed by depositing a metal layer on the buffer layer 109 and then patterning the metal layer using a photolithography and etching process, but the embodiment of the present disclosure is not limited thereto.

[0085] Reference FIG. 3A to FIG. 3C, the color filter layer 120 also includes a color filter separation grid 113B and a plurality of color filter segments 115. The color filter segments 115 correspond to the photoelectric conversion elements 103, and the color filter separation grid 113B is disposed between the color filter segments 115 and on the metal grid 111. In the embodiment of the present disclosure, the metal grid 111, the color filter separation grid 113B, and the color filter segments 115 may be referred to as the color filter layer 120. In particular, the color filter separation grid 113B may be formed on and cover at least a portion of the metal grid 111, and the color filter segments 115 may be disposed in respective spaces of the color filter separation grid 113B. The material of the color filter separation grid 113B may include a transparent dielectric material having a low refractive index of about 1.0 to about 1.99, and the refractive index of the color filter separation grid 113B is lower than the refractive index of the color filter segment 115, but the embodiment of the present disclosure is not limited thereto. Each color filter segment 115 may correspond to a corresponding photoelectric conversion element 103, but the embodiment of the present disclosure is not limited thereto.

[0086] In addition, in some embodiments, the color filter segment 115 includes a red (R) filter segment 115R and a green (G) / blue (B) filter segment 115GB. FIG. 3A to FIG. 3C In some other embodiments, the color filter segments 115 may also include white (W) or other color color filter segments, which are arranged together with the red, green and blue filter segments in a suitable arrangement. The top surface of the color filter segment 115 may be flush with the top surface of the color filter separation grid 113B, but the embodiments of the present disclosure are not limited thereto.

[0087] Reference FIG. 3A to FIG. 3C The solid-state imaging device 200 further includes a light waveguide layer 130 disposed above the color filter layer 120. FIG. 3A to FIG. 3C As shown, the optical waveguide layer 130 includes a waveguide separation grid 123A, a waveguide material 121 in the gaps of the waveguide separation grid 123A (and located above the photoelectric conversion element 103), and an anti-reflection film 123B on the waveguide separation grid 123A and the waveguide material 121. In more detail, as shown in FIG. FIG. 3A to FIG. 3C As shown, the waveguide separation grid 123A can be arranged corresponding to the color filter separation grid 113B, the waveguide material 121 and the waveguide separation grid 123A have a coplanar top surface, and the anti-reflection film 123B is located on the coplanar top surface, but the embodiment of the present disclosure is not limited to this.

[0088] In some embodiments, the material of the waveguide separation grid 113A includes a transparent dielectric material having a low refractive index of about 1.0 to about 1.99. The material of the waveguide material 121 includes another transparent dielectric material having a higher refractive index than the waveguide separation grid 113A, but the embodiments of the present disclosure are not limited thereto. In some embodiments, the refractive index of the waveguide material 121 is about 1.1 to about 2.0. In some embodiments, the waveguide separation grid 123A and the anti-reflection film 123B may be made of the same material and may be formed together in the same process step.

[0089] In the embodiment of the present disclosure, the width of the top of the waveguide separation grid 123A is greater than the width of the bottom of the waveguide separation grid 123A. FIG. 3A to FIG. 3C In the cross-sectional view of the solid-state imaging device 200 shown, the waveguide separation grid 123A may be formed into a plurality of trapezoids, but the embodiment of the present disclosure is not limited thereto.

[0090] In some embodiments, the waveguide separation grid 123A is as follows Figure 2A and Figure 3A As shown, there is a first waveguide portion 123A1 in the region ROI-1. Figure 2B and Figure 3B (or Figure 2C and Figure 3C ) shows that a second waveguide portion 123A2 (or 123A2') corresponding to the first waveguide portion 123A1 is provided in the region ROI-2 (or the region ROI-3). In addition, the second waveguide width WW2 (or WW2') at the top of the second waveguide portion 123A2 (or 123A2') is greater than the first waveguide width WW1 at the top of the first waveguide portion 123A1. In this embodiment, the second waveguide width WW2' at the top of the second waveguide portion 123A2' is greater than the second waveguide width WW2 at the top of the second waveguide portion 123A2. That is, the second waveguide width WW2 at the top of the second waveguide portion 123A2 in the region ROI-2 (i.e., between the central region and the edge region of the solid-state imaging device 200) or the second waveguide width WW2' at the top of the second waveguide portion 123A2' in the region ROI-3 (i.e., the edge region of the solid-state imaging device 200) is greater than the first waveguide width WW1 at the top of the first waveguide portion 123A1 in the region ROI-1 (i.e., the central region of the solid-state imaging device 200).

[0091] like Figure 2A , Figure 2B , Figure 3A and Figure 3BAs shown, for example, the first waveguide width WW1 at the top of the first waveguide portion 123A1 may be about 0.15 μm to about 0.22 μm, and the second waveguide width WW2 at the top of the second waveguide portion 123A2 may be about 0.17 μm to about 0.24 μm, but the embodiments of the present disclosure are not limited thereto. Figure 2C and Figure 3C As shown, the second waveguide width WW2' at the top of the second waveguide portion 123A2' may be about 0.19 μm to about 0.29 μm, but the embodiment of the present disclosure is not limited thereto. In some embodiments, the ratio of the second waveguide width WW2 (or WW2') at the top of the second waveguide portion 123A2 (or 123A2') to the first waveguide width WW1 at the top of the first waveguide portion 123A1 (WW2 / WW1 or WW2' / WW1) may be about 1.05 to about 1.3, but the embodiment of the present disclosure is not limited thereto.

[0092] Furthermore, in FIG. 2A to FIG. 2C and FIG. 3A to FIG. 3C In the illustrated embodiment, the first waveguide portion 123A1 in the region ROI-1 and the second waveguide portion 123A2 (or 123A2') in the region ROI-2 (or region ROI-3) surround a space corresponding to the red filter segment 115R. FIG. 2A to FIG. 2C As shown, since the second waveguide width WW2 (or WW2') at the top of the second waveguide portion 123A2 (or 123A2') is greater than the first waveguide width WW1 at the top of the first waveguide portion 123A1, the top surface 121R of the waveguide material 121 corresponding to each red filter segment 115R in the region ROI-2 (i.e., between the central region and the edge region of the solid-state imaging device 200) or the region ROI-3 (i.e., the edge region of the solid-state imaging device 200) is smaller than the top surface 121R of the waveguide material 121 corresponding to each red filter segment 115R in the region ROI-1 (i.e., the central region of the solid-state imaging device 200). Figure 2B and Figure 2C As shown, in the region ROI-2 or the region ROI-3, the top surface 121R of the waveguide material 121 corresponding to each red filter segment 115R is smaller than the top surface 121GB of the waveguide material 121 corresponding to each green / blue filter segment 115GB.

[0093] In some embodiments, the position of the waveguide separation grid 123A in the region ROI-2 (i.e., between the central region and the edge region of the solid-state imaging device 200) or the region ROI-3 (i.e., the edge region of the solid-state imaging device 200) is offset by a displacement distance in the direction D relative to the position of the color filter separation grid 113B. Here, the direction D is a horizontal direction on a plane parallel to the top surface of the color filter layer 120. The displacement distance of the waveguide separation grid 123A can be adjusted according to the sensitivity, channel separation or other performance in the region ROI-2 or the region ROI-3 of the solid-state imaging device 200. In some embodiments, the displacement distance of the waveguide separation grid 123A is consistent, but the embodiments of the present disclosure are not limited thereto. In some other embodiments, the displacement distance of the waveguide separation grid 123A is variable.

[0094] According to the embodiment of the present disclosure, in the region ROI-2 or the region ROI-3, oblique incident light irradiated to the solid-state imaging device 200 having the positionally shifted waveguide partitioning grid 123A can be guided into the color filter segment 115 and reaches a position close to the central region of the photoelectric conversion element 103. Therefore, the sensitivity in (or near) the edge region (peripheral region) of the solid-state imaging device 200 can be enhanced.

[0095] Furthermore, due to the higher refractive index, the red filter segment 115R may have a higher sensitivity than the green / blue filter segment 115GB in the region ROI-2 (i.e., between the central region and the edge region of the solid-state imaging device 200) or the region ROI-3 (i.e., the edge region of the solid-state imaging device 200). In the embodiment of the present disclosure, the second waveguide width WW2 (or WW2') at the top of the second waveguide portion 123A2 (or 123A2') is set to be larger than the first waveguide width WW1 at the top of the first waveguide portion 123A1, which can reduce the difference in sensitivity between the color filter segments 115. Therefore, the uniformity of sensitivity in (or near) the edge region (peripheral region) of the solid-state imaging device 200 can be improved.

[0096] Figure 4A A partial cross-sectional view of a region ROI- 1 of the solid-state imaging device 300 according to some embodiments of the present disclosure is shown. Figure 4B A partial cross-sectional view of a region ROI- 3 of a solid-state imaging device 300 according to some embodiments of the present disclosure is shown. Figure 4A and Figure 4B The relative positions of ROI-1 and ROI-3 in the Figure 1 It should be noted that for the sake of brevity, Figure 4A and Figure 4BSome components of the solid-state imaging device 300 may be omitted.

[0097] Reference Figure 4A and Figure 4B In some embodiments, the photoelectric conversion elements 103 in the solid-state imaging device 300 may be arranged in a plurality of regular pixels P and a plurality of phase detection auto focus pixels (phase detection auto focus pixels) PDAF, and the phase detection auto focus pixels PDAF are surrounded by the regular pixels P. In some embodiments, each phase detection auto focus pixel PDAF may correspond to at least two photoelectric conversion elements 103, and each regular pixel P may correspond to one photoelectric conversion element, but the embodiments of the present disclosure are not limited thereto.

[0098] In this embodiment, the metal grid 111 has different widths in different areas of the solid-state imaging device 300. For example, Figure 4A and Figure 4B As shown, the metal grid 111 has a first metal portion 111A in the region ROI-1 (i.e., the central region of the solid-state imaging device 300), and has a second metal portion 111B corresponding to the first metal portion 111A in the region ROI-3 (i.e., the edge region of the solid-state imaging device 300), but the disclosed embodiment is not limited thereto. In some other embodiments, the second metal portion 111B of the metal grid 111 may also be disposed in the region ROI-2 (i.e., between the central region and the edge region of the solid-state imaging device 300).

[0099] In this embodiment, the first metal portion 111A and the second metal portion 111B of the metal grid 111 correspond to the space between a phase detection autofocus pixel PDAF and a corresponding regular pixel P (i.e., the regular pixel P surrounding the phase detection autofocus pixel PDAF). In addition, the second metal width MW2 of the second metal portion 111B is greater than the first metal width MW1 of the first metal portion 111A. In more detail, in Figure 4B In the region ROI-3 shown in FIG. 1 , the second metal portion 111B of the metal grid 111 may be partially located under the color filter segment 115 corresponding to the regular pixel P. Figure 4A In the illustrated region ROI- 1 , the first metal portion 111A of the metal grid 111 may be completely covered by the color filter separation grid 113B.

[0100] In some embodiments, a ratio (MW2 / MW1) of the second metal width MW2 of the second metal portion 111B to the first metal width MW1 of the first metal portion 111A may be about 1.2 to about 1.75, but the embodiments of the present disclosure are not limited thereto.

[0101] Since the regular pixels P around the phase detection autofocus pixel PDAF in the region ROI-3 (or region ROI-2) have higher sensitivity than other regular pixels P, the sensitivity of the region ROI-3 (or region ROI-2) may be unbalanced. In an embodiment of the present disclosure, the second metal width MW2 of the second metal portion 111B is set to be greater than the first metal width MW1 of the first metal portion 111A, which can reduce the difference in sensitivity between the regular pixels P. Therefore, the uniformity of the sensitivity in (or near) the edge region (peripheral region) of the solid-state imaging device 300 can be improved.

[0102] In some embodiments, Figure 4B As shown, in the region ROI-3, the color filter separation grid 113B has a grid width CW, and the grid width CW may be smaller than the second metal width MW2 of the second metal portion 111B, but the embodiment of the disclosure is not limited thereto.

[0103] Figure 5A A partial cross-sectional view of a region ROI- 1 of a solid-state imaging device 400 according to some embodiments of the present disclosure is shown. Figure 5B A partial cross-sectional view of a region ROI- 3 of a solid-state imaging device 400 according to some embodiments of the present disclosure is shown. Figure 5A and Figure 5B The relative positions of ROI-1 and ROI-3 in the Figure 1 It should be noted that for the sake of brevity, Figure 5A and Figure 5B Some components of the solid-state imaging device 400 may be omitted.

[0104] Reference Figure 5A and Figure 5B In some embodiments, the photoelectric conversion elements 103 in the solid-state imaging device 400 may be arranged in a plurality of regular pixels P and a plurality of phase detection autofocus pixels PDAF, and the phase detection autofocus pixels PDAF are surrounded by the regular pixels P. Similarly, each phase detection autofocus pixel PDAF may correspond to at least two photoelectric conversion elements 103, and each regular pixel P may correspond to one photoelectric conversion element, but the embodiments of the present disclosure are not limited thereto.

[0105] like Figure 5A and Figure 5B As shown, in some embodiments, the photoelectric conversion element 103 in the solid-state imaging device 400 may be further arranged in a plurality of additional regular pixels P1, and the additional regular pixels P1 are separated from the phase detection auto focus pixels PDAF by the regular pixels P.

[0106] In the present embodiment, the waveguide partitioning grid 123A has different widths in different regions of the solid-state imaging device 400. For example, Figure 5A and Figure 5B As shown, the waveguide separation grid 123A has a first waveguide portion 123A1 in the region ROI-1 (i.e., the central region of the solid-state imaging device 400), and has a second waveguide portion 123A2 corresponding to the first waveguide portion 123A1 in the region ROI-3 (i.e., the edge region of the solid-state imaging device 400), but the disclosed embodiment is not limited thereto. In some other embodiments, the second waveguide portion 123A2 of the waveguide separation grid 123A may also be disposed in the region ROI-2 (i.e., between the central region and the edge region of the solid-state imaging device 400).

[0107] In the present embodiment, the first waveguide portion 123A1 and the second waveguide portion 123A2 of the waveguide partitioning grid 123A correspond to the space between one phase detection autofocus pixel PDAF and the corresponding regular pixel P (i.e., the regular pixel P surrounding this phase detection autofocus pixel PDAF). In addition, the second waveguide width WW2 at the top of the second waveguide portion 123A2 is greater than the first waveguide width WW1 at the top of the first waveguide portion 123A1.

[0108] In some embodiments, Figure 5B As shown, in the region ROI-3 (or region ROI-2), the top surface 121A of the waveguide material 121 corresponding to a regular pixel is smaller than the top surface 121B of the waveguide material 121 corresponding to an additional regular pixel P1, but the embodiments of the present disclosure are not limited thereto.

[0109] Since the regular pixels P around the phase detection autofocus pixel PDAF in the region ROI-3 (or region ROI-2) have higher sensitivity than other regular pixels P, the sensitivity of the region ROI-3 (or region ROI-2) may be unbalanced. In the embodiment of the present disclosure, the second waveguide width WW2 at the top of the second waveguide portion 123A2 is set to be larger than the first waveguide width WW1 at the top of the first waveguide portion 123A1, which can reduce the difference in sensitivity between the regular pixels P. Therefore, the uniformity of the sensitivity in (or near) the edge region (peripheral region) of the solid-state imaging device 400 can be improved.

[0110] In this embodiment, if Figure 5BAs shown, the waveguide partition grid 123A may have a third waveguide portion 123A3 in the region ROI-3 (i.e., the edge region of the solid-state imaging device 400), and the third waveguide portion 123A3 corresponds to an additional regular pixel P1. In addition, the second waveguide width WW2 at the top of the second waveguide portion 123A2 is greater than the third waveguide width WW3 at the top of the third waveguide portion 123A3, but the embodiment of the present disclosure is not limited thereto.

[0111] Fig. 6A A partial cross-sectional view of a region ROI- 1 of a solid-state imaging device 500 according to some embodiments of the present disclosure is shown. Figure 6B A partial cross-sectional view of a region ROI- 3 of a solid-state imaging device 500 according to some embodiments of the present disclosure is shown. Fig. 6A and Figure 6B The relative positions of ROI-1 and ROI-3 in the Figure 1 It should be noted that for the sake of brevity, Fig. 6A and Figure 6B Some components of the solid-state imaging device 500 may be omitted.

[0112] Reference Fig. 6A and Figure 6B In some embodiments, the photoelectric conversion elements 103 in the solid-state imaging device 500 may be arranged in a plurality of regular pixels P and a plurality of phase detection autofocus pixels PDAF, and the phase detection autofocus pixels PDAF are surrounded by the regular pixels P. Similarly, each phase detection autofocus pixel PDAF may correspond to at least two photoelectric conversion elements 103, and each regular pixel P may correspond to one photoelectric conversion element, but the embodiments of the present disclosure are not limited thereto.

[0113] In this embodiment, the color filter separation grid 113B has different widths in different areas of the solid-state imaging device 500. For example, Fig. 6A and Figure 6B As shown, the color filter separation grid 113B has a first color portion 113B1 in the region ROI-1 (i.e., the central region of the solid-state imaging device 500), and has a second color portion 113B2 corresponding to the first color portion 113B1 in the region ROI-3 (i.e., the edge region of the solid-state imaging device 500), but the disclosed embodiment is not limited thereto. In some other embodiments, the second color portion 113B2 of the color filter separation grid 113B may also be disposed in the region ROI-2 (i.e., between the central region and the edge region of the solid-state imaging device 500).

[0114] In the present embodiment, the first color portion 113B1 and the second color portion 113B2 of the color filter partition grid 113B correspond to the space between one phase detection auto focus pixel PDAF and the corresponding regular pixel P (i.e., the regular pixel P surrounding this phase detection auto focus pixel PDAF). In addition, the second color width CW2 of the bottom of the second color portion 113B2 is smaller than the first color width CW1 of the bottom of the first color portion 113B1.

[0115] exist Fig. 6A and Figure 6B In the illustrated embodiment, a bottom surface 115B2 of a color filter segment surrounded by a second color portion 113B2 (which corresponds to a phase detection autofocus pixel PDAF in the region ROI-3 or the region ROI-2) is larger than a bottom surface 115B1 of another color filter segment 115 surrounded by a first color portion 113B1 (which corresponds to a phase detection autofocus pixel PDAF in the region ROI-1).

[0116] Since the regular pixels P around the phase detection autofocus pixels PDAF in the region ROI-3 (or region ROI-2) have higher sensitivity than other regular pixels P, the sensitivity of the region ROI-3 (or region ROI-2) may be unbalanced. In the embodiment of the present disclosure, the second color width CW2 at the bottom of the second color portion 113B2 is set to be smaller than the first color width CW1 at the bottom of the first color portion 113B1, which can reduce the difference in sensitivity between the regular pixels P. Therefore, the uniformity of the sensitivity in (or near) the edge region (peripheral region) of the solid-state imaging device 500 can be improved.

[0117] Fig. 7A A partial cross-sectional view of a region ROI- 1 of a solid-state imaging device 600 according to some embodiments of the present disclosure is shown. Figure 7B A partial cross-sectional view of a region ROI- 3 of a solid-state imaging device 600 according to some embodiments of the present disclosure is shown. Fig. 7A and Figure 7B The relative positions of ROI-1 and ROI-3 in the Figure 1 It should be noted that for the sake of brevity, Fig. 7A and Figure 7B Some components of the solid-state imaging device 600 may be omitted.

[0118] Reference Fig. 7A and Figure 7BIn some embodiments, the photoelectric conversion elements 103 in the solid-state imaging device 600 may be arranged in a plurality of regular pixels P and a plurality of phase detection autofocus pixels PDAF, and the phase detection autofocus pixels PDAF are surrounded by the regular pixels P. Similarly, each phase detection autofocus pixel PDAF may correspond to at least two photoelectric conversion elements 103, and each regular pixel P may correspond to one photoelectric conversion element, but the embodiments of the present disclosure are not limited thereto.

[0119] In the present embodiment, the waveguide partitioning grid 123A has different widths in different regions of the solid-state imaging device 600. For example, Fig. 7A and Figure 7B As shown, the waveguide separation grid 123A has a first waveguide portion 123A1 in the region ROI-1 (i.e., the central region of the solid-state imaging device 600), and has a second waveguide portion 123A2 corresponding to the first waveguide portion 123A1 in the region ROI-3 (i.e., the edge region of the solid-state imaging device 600), but the disclosed embodiment is not limited thereto. In some other embodiments, the second waveguide portion 123A2 of the waveguide separation grid 123A may also be disposed in the region ROI-2 (i.e., between the central region and the edge region of the solid-state imaging device 600).

[0120] In the present embodiment, the first waveguide portion 123A1 and the second waveguide portion 123A2 of the waveguide partitioning grid 123A correspond to the space between one phase detection autofocus pixel PDAF and the corresponding regular pixel P (i.e., the regular pixel P surrounding this phase detection autofocus pixel PDAF). In addition, the first waveguide width WW1 at the top of the first waveguide portion 123A1 is greater than the second waveguide width WW2 at the top of the second waveguide portion 123A2.

[0121] like Fig. 7A and Figure 7B As shown, the top surface 121A1 of the waveguide material 121 surrounded by the first waveguide portion 123A1 (which corresponds to a phase detection autofocus pixel PDAF in the region ROI-1) is smaller than the top surface 121A2 of the waveguide material 121 surrounded by the second waveguide portion (which corresponds to a phase detection autofocus pixel PDAF in the region ROI-3 or the region ROI-2).

[0122] In the embodiment of the present disclosure, the first waveguide width WW1 of the top of the first waveguide portion 123A1 is set larger than the second waveguide width WW2 of the top of the second waveguide portion 123A2 , which can improve the uniformity of the sensitivity of the solid-state imaging device 600 .

[0123] Fig. 8AA partial cross-sectional view of a solid-state imaging device 700 according to some embodiments of the present disclosure is shown. Figure 8B FIG. 8 is a partial cross-sectional view of a solid-state imaging device 800 according to some embodiments of the present disclosure. It should be noted that for the sake of brevity, Fig. 8A and Figure 8B Some components of the solid-state imaging device 700 or the solid-state imaging device 800 may be omitted.

[0124] like Fig. 8A As shown, the contour of the waveguide material 121 in the gap may be triangular; Figure 8B As shown, the contour of the waveguide material 121 in the gap may be an arc, but the embodiments of the present disclosure are not limited thereto. In some embodiments, the waveguide material 121 in the gap may have a contour including a rectangle, a triangle, other polygons, an arc, or a combination thereof.

[0125] In summary, according to the embodiments of the present disclosure, by adjusting the width of some components in the solid-state imaging device, the difference in sensitivity between the color filter segments can be reduced. Therefore, the uniformity of sensitivity in (or near) the edge or peripheral area of ​​the solid-state imaging device can be improved.

[0126] The above summarizes the components of several embodiments so that technicians in the technical field to which the present disclosure belongs can better understand the viewpoints of the embodiments of the present disclosure. It should be understood by technicians in the technical field to which the present disclosure belongs that they can design or modify other processes and structures based on the embodiments of the present disclosure to achieve the same purposes and / or advantages as the embodiments introduced herein. It should also be understood by technicians in the technical field to which the present disclosure belongs that such equivalent structures do not deviate from the spirit and scope of the present disclosure, and they can make various changes, substitutions and replacements without violating the spirit and scope of the present disclosure. Therefore, the scope of protection of the present disclosure shall be determined by the attached claims. In addition, although the present disclosure has been disclosed as above with several preferred embodiments, it is not intended to limit the present disclosure.

[0127] References throughout this specification to features, advantages, or similar language do not imply that all features and advantages that may be realized using the present disclosure should or may be realized in any single embodiment of the present disclosure. Conversely, language referring to features and advantages is understood to mean that a particular feature, advantage, or characteristic described in conjunction with an embodiment is included in at least one embodiment of the present disclosure. Thus, discussions of features and advantages and similar language throughout this specification may, but do not necessarily, represent the same embodiment.

[0128] Furthermore, in one or more embodiments, the described features, advantages, and characteristics of the present disclosure may be combined in any suitable manner. Based on the description herein, those skilled in the relevant art will appreciate that the present disclosure may be implemented without one or more specific features or advantages of a particular embodiment. In other cases, additional features and advantages may be identified in certain embodiments, which may not be present in all embodiments of the present disclosure.

Claims

1. A solid-state imaging device having a first area and a second area surrounding the first area, the solid-state imaging device comprising: a substrate having a plurality of photoelectric conversion elements; a color filter layer disposed on the substrate and comprising a plurality of color filter segments, wherein the plurality of color filter segments correspond to the plurality of photoelectric conversion elements; and an optical waveguide layer disposed above the color filter layer and comprising a waveguide separation grid, a waveguide material in the gaps of the waveguide separation grid, and an anti-reflection film on the waveguide separation grid and the waveguide material, The width of the top of the waveguide separation grid is greater than the width of the bottom of the waveguide separation grid, the waveguide separation grid has a first waveguide portion in the first area, and a second waveguide portion corresponding to the first waveguide portion in the second area, a second waveguide width at the top of the second waveguide portion is greater than a first waveguide width at the top of the first waveguide portion, and a ratio of the second waveguide width to the first waveguide width is 1.05 to 1.

3.

2. A solid-state imaging device as described in claim 1, wherein the plurality of color filter segments include a plurality of red filter segments and a plurality of green filter segments and / or blue filter segments, the first waveguide portion and the second waveguide portion surround a space corresponding to the plurality of red filter segments, and in the second region, a top surface of the waveguide material corresponding to each of the plurality of red filter segments is smaller than a top surface of the waveguide material corresponding to each of the plurality of green filter segments and / or blue filter segments.

3. A solid-state imaging device having a first area and a second area surrounding the first area, the solid-state imaging device comprising: a substrate having a plurality of photoelectric conversion elements; a color filter layer disposed on the substrate and comprising a plurality of color filter segments, wherein the plurality of color filter segments correspond to the plurality of photoelectric conversion elements; and an optical waveguide layer disposed above the color filter layer and comprising a waveguide separation grid, a waveguide material in the gaps of the waveguide separation grid, and an anti-reflection film on the waveguide separation grid and the waveguide material, The width of the top of the waveguide partition grid is greater than the width of the bottom of the waveguide partition grid, a plurality of the photoelectric conversion elements are arranged in a plurality of regular pixels and a plurality of phase detection autofocus pixels, a plurality of the phase detection autofocus pixels are surrounded by a plurality of the regular pixels, each of the plurality of the phase detection autofocus pixels corresponds to at least two of the plurality of the photoelectric conversion elements, and each of the plurality of the regular pixels corresponds to one of the plurality of the photoelectric conversion elements, The color filter layer also includes a metal grid arranged between the plurality of color filter segments, the metal grid having a first metal portion in the first region, and a second metal portion corresponding to the first metal portion in the second region, a second metal width of the second metal portion being greater than a first metal width of the first metal portion, and a ratio of the second metal width to the first metal width being 1.2 to 1.

75.

4. A solid-state imaging device as described in claim 3, wherein the first metal portion and the second metal portion correspond to the space between one of the plurality of phase detection autofocus pixels and the plurality of regular pixels surrounding the phase detection autofocus pixel, and the plurality of color filter segments cover a portion of the second metal portion in the plurality of regular pixels.

5. The solid-state imaging device as described in claim 3, wherein the first metal portion and the second metal portion correspond to the space between one of the plurality of phase detection autofocus pixels and the plurality of regular pixels surrounding the phase detection autofocus pixel, and the color filter layer further includes a color filter separation grid arranged between the plurality of color filter segments and on the metal grid, and the color filter separation grid has a grid width smaller than the second metal width of the second metal portion.

6. A solid-state imaging device having a first area and a second area surrounding the first area, the solid-state imaging device comprising: a substrate having a plurality of photoelectric conversion elements; a color filter layer disposed on the substrate and comprising a plurality of color filter segments, wherein the plurality of color filter segments correspond to the plurality of photoelectric conversion elements; and an optical waveguide layer disposed above the color filter layer and comprising a waveguide separation grid, a waveguide material in the gaps of the waveguide separation grid, and an anti-reflection film on the waveguide separation grid and the waveguide material, The width of the top of the waveguide partition grid is greater than the width of the bottom of the waveguide partition grid, a plurality of the photoelectric conversion elements are arranged in a plurality of regular pixels and a plurality of phase detection autofocus pixels, a plurality of the phase detection autofocus pixels are surrounded by a plurality of the regular pixels, each of the plurality of the phase detection autofocus pixels corresponds to at least two of the plurality of the photoelectric conversion elements, and each of the plurality of the regular pixels corresponds to one of the plurality of the photoelectric conversion elements, The waveguide separation grid has a first waveguide portion in the first area, a second waveguide portion corresponding to the first waveguide portion in the second area, and a second waveguide width at the top of the second waveguide portion is greater than a first waveguide width at the top of the first waveguide portion.

7. The solid-state imaging device of claim 6 , wherein the first waveguide portion and the second waveguide portion correspond to a space between one of the plurality of phase detection autofocus pixels and a plurality of the regular pixels surrounding the phase detection autofocus pixel, the color filter layer further comprises a color filter partitioning grid disposed between the plurality of color filter segments, the plurality of the photoelectric conversion elements are further arranged in a plurality of additional regular pixels, the plurality of the additional regular pixels are separated from the plurality of the phase detection autofocus pixels by the plurality of the regular pixels, and in the second region, a top surface of the waveguide material corresponding to one of the plurality of the regular pixels is smaller than a top surface of the waveguide material corresponding to one of the plurality of the additional regular pixels.

8. A solid-state imaging device having a first area and a second area surrounding the first area, the solid-state imaging device comprising: a substrate having a plurality of photoelectric conversion elements; a color filter layer disposed on the substrate and comprising a plurality of color filter segments, wherein the plurality of color filter segments correspond to the plurality of photoelectric conversion elements; and an optical waveguide layer disposed above the color filter layer and comprising a waveguide separation grid, a waveguide material in the gaps of the waveguide separation grid, and an anti-reflection film on the waveguide separation grid and the waveguide material, The width of the top of the waveguide partition grid is greater than the width of the bottom of the waveguide partition grid, a plurality of the photoelectric conversion elements are arranged in a plurality of regular pixels and a plurality of phase detection autofocus pixels, a plurality of the phase detection autofocus pixels are surrounded by a plurality of the regular pixels, each of the plurality of the phase detection autofocus pixels corresponds to at least two of the plurality of the photoelectric conversion elements, and each of the plurality of the regular pixels corresponds to one of the plurality of the photoelectric conversion elements, The color filter layer further includes a color filter separation grid disposed between the plurality of color filter segments, the color filter separation grid having a first color portion in the first region, a second color portion corresponding to the first color portion in the second region, and a second color width at the bottom of the second color portion being smaller than a first color width at the bottom of the first color portion, The first color portion and the second color portion correspond to the space between one of the multiple phase detection autofocus pixels and the multiple regular pixels surrounding the phase detection autofocus pixel, and the bottom surface of one of the multiple color filter segments surrounded by the second color portion is larger than the bottom surface of another of the multiple color filter segments surrounded by the first color portion.

9. A solid-state imaging device having a first area and a second area surrounding the first area, the solid-state imaging device comprising: a substrate having a plurality of photoelectric conversion elements; a color filter layer disposed on the substrate and comprising a plurality of color filter segments, wherein the plurality of color filter segments correspond to the plurality of photoelectric conversion elements; and an optical waveguide layer disposed above the color filter layer and comprising a waveguide separation grid, a waveguide material in the gaps of the waveguide separation grid, and an anti-reflection film on the waveguide separation grid and the waveguide material, The width of the top of the waveguide partition grid is greater than the width of the bottom of the waveguide partition grid, a plurality of the photoelectric conversion elements are arranged in a plurality of regular pixels and a plurality of phase detection autofocus pixels, a plurality of the phase detection autofocus pixels are surrounded by a plurality of the regular pixels, each of the plurality of the phase detection autofocus pixels corresponds to at least two of the plurality of the photoelectric conversion elements, and each of the plurality of the regular pixels corresponds to one of the plurality of the photoelectric conversion elements, The waveguide separation grid has a first waveguide portion in the first area and a second waveguide portion corresponding to the first waveguide portion in the second area, a first waveguide width at the top of the first waveguide portion is greater than a second waveguide width at the top of the second waveguide portion, and a top surface of the waveguide material surrounded by the first waveguide portion is smaller than a top surface of the waveguide material surrounded by the second waveguide portion.

10. The solid-state imaging device as claimed in claim 1, wherein the waveguide material in the gap has a profile, and the profile includes a rectangle, a triangle, an arc or a combination thereof.

Images