Photodetector

Abstract

The photodetector includes a photoelectric conversion unit and an optical layer disposed to cover the photoelectric conversion unit. The optical layer includes: a plurality of pillars arranged side by side in a plane direction of the layer to guide at least light to be detected among incident light to the photoelectric conversion unit; and a filler provided to fill a space between the plurality of pillars. The side surface of the pillar has a curved line protruding toward the outside of the pillar.

Description

Technical Field

[0001] The present disclosure relates to a photodetector. Background Art

[0002] For example, as disclosed in Patent Document 1, there is known a technique for controlling the direction of incident light by arranging multiple fine structures having a size smaller than the wavelength of light side by side in a planar direction. Because the structures have, for example, a columnar shape extending in a direction orthogonal to the planar direction or a shape based on a columnar shape, they are also referred to as "pillars" in this disclosure.

[0003] Reference List

[0004] Patent Literature

[0005] Patent Document 1: JP 2020-537193 A Summary of the Invention

[0006] Technical issues

[0007] Since the pillars are delicate structures, there is a possibility that the pillars may fall.

[0008] One aspect of the present disclosure inhibits pillar collapse.

[0009] Solution to the problem

[0010] According to one aspect of the present disclosure, a photodetector includes: a photoelectric conversion unit; and an optical layer, which is configured to cover the photoelectric conversion unit, wherein the optical layer includes: a plurality of pillars, arranged side by side in the planar direction of the layer to guide at least the light to be detected in the incident light to the photoelectric conversion unit; and a filler, which is configured to fill the space between the plurality of pillars, and the side surface of the pillar has a curved surface convex toward the outside of the pillar.

[0011] According to one aspect of the present disclosure, a photodetector includes: a photoelectric conversion unit; and an optical layer, which is configured to cover the photoelectric conversion unit, wherein the optical layer includes: a plurality of pillars arranged side by side in the planar direction of the layer to guide at least the light to be detected in the incident light to the photoelectric conversion unit; a reflection suppression film, which is arranged on the lower surface of the pillar; and a filler, which is configured to fill the space between the plurality of pillars and cover the reflection suppression film, and the reflection suppression film includes: an upper end portion, which is located on the lower surface of the pillar and has an upper surface of the reflection suppression film; a lower end portion, which has a lower surface of the reflection suppression film; and a middle portion, which is located between the upper end portion and the lower end portion and has a width smaller than the width of the upper end portion.

[0012] According to one aspect of the present disclosure, a photodetector includes: a photoelectric conversion unit; and an optical layer configured to cover the photoelectric conversion unit, wherein the optical layer includes: a plurality of pillars arranged side by side in the planar direction of the layer to guide at least the light to be detected in the incident light to the photoelectric conversion unit; and a film configured to cover at least the side surfaces of the pillars.

[0013] According to one aspect of the present disclosure, a photodetector includes: a photoelectric conversion unit; and an optical layer, which is configured to cover the photoelectric conversion unit, wherein the optical layer includes: a plurality of pillars arranged side by side in the planar direction of the layer to guide at least the light to be detected in the incident light to the photoelectric conversion unit; and a reflection suppression film, which is arranged on the upper surface of the plurality of pillars, and the reflection suppression film includes: a first part, each located on the upper surface of the corresponding pillar; and a second part, connecting the first parts located on the upper surfaces of adjacent pillars. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a diagram showing an example of a schematic configuration of the photodetector 100 .

[0015] Figure 2 is a diagram showing an example of a circuit configuration of the pixel 2 .

[0016] Figure 3 is a diagram showing an example of a schematic configuration of the pixel array section 1 .

[0017] Figure 4 is a diagram showing an example of a schematic configuration of the optical layer 6 .

[0018] Figure 5 is a diagram illustrating an example of a schematic configuration of the optical layer 6 .

[0019] Figure 6 is a diagram showing an example of a schematic configuration of the support column 62 and its peripheral structure.

[0020] Figure 7 is a diagram showing an example of a schematic configuration of the support column 62 and its peripheral structure.

[0021] Figure 8 is a diagram showing an example of the support column 62 and its peripheral structure.

[0022] Figure 9 is a diagram illustrating an example of a manufacturing method.

[0023] Figure 10 is a diagram illustrating an example of a manufacturing method.

[0024] Figure 11 is a diagram illustrating an example of a manufacturing method.

[0025] Figure 12 is a diagram illustrating an example of a manufacturing method.

[0026] Figure 13 is a diagram illustrating an example of a manufacturing method.

[0027] Figure 14 is a diagram showing an example of a schematic configuration of the optical layer 6 .

[0028] Figure 15 is a diagram illustrating an example of a manufacturing method.

[0029] Figure 16 is a diagram illustrating an example of a manufacturing method.

[0030] Figure 17 is a diagram showing an example of a schematic configuration of the optical layer 6 .

[0031] Figure 18 is a diagram illustrating an example of a manufacturing method.

[0032] Figure 19 is a diagram showing an example of the effective refractive index.

[0033] Figure 20 is a diagram showing an example of the effective refractive index.

[0034] Figure 21 is a diagram showing an example of a schematic configuration of the optical layer 6 .

[0035] Figure 22 is a diagram showing an example of a planar layout of the support column 62 .

[0036] Figure 23 6 and 7 are diagrams showing examples of cross-sectional shapes of the pillar 62 and the membrane 67 .

[0037] Figure 24 6 and 7 are diagrams showing examples of cross-sectional shapes of the pillar 62 and the membrane 67 .

[0038] Figure 25 6 and 7 are diagrams showing examples of cross-sectional shapes of the pillars 62 and the membrane 67 .

[0039] Figure 26 is a diagram showing an example of a schematic configuration of the optical layer 6 .

[0040] Figure 27 is a diagram showing an example of a schematic configuration of the optical layer 6 .

[0041] Figure 28 is a diagram showing an example of a schematic configuration of the optical layer 6 .

[0042] Figure 29is a diagram illustrating an example of a schematic configuration of the optical layer 6 .

[0043] Figure 30 This is an enlarged view of the neck C and its surroundings.

[0044] Figure 31 is a diagram showing an example of a schematic configuration of the optical layer 6 .

[0045] Figure 32 is a diagram showing an example of a schematic configuration of the optical layer 6 .

[0046] Figure 33 is a diagram illustrating an example of a manufacturing method.

[0047] Figure 34 is a diagram illustrating an example of a manufacturing method.

[0048] Figure 35 is a diagram illustrating an example of a manufacturing method.

[0049] Figure 36 is a diagram illustrating an example of a manufacturing method.

[0050] Figure 37 is a diagram illustrating an example of a manufacturing method.

[0051] Figure 38 is a diagram illustrating an example of a manufacturing method.

[0052] Figure 39 is a diagram illustrating an example of a manufacturing method.

[0053] Figure 40 is a diagram illustrating an example of a manufacturing method.

[0054] Figure 41 is a diagram illustrating an example of a manufacturing method.

[0055] Figure 42 is a diagram illustrating an example of a manufacturing method.

[0056] Figure 43 is a diagram illustrating an example of a manufacturing method.

[0057] Figure 44 is a diagram illustrating an example of a manufacturing method.

[0058] Figure 45 is a diagram illustrating an example of a manufacturing method.

[0059] Figure 46 is a diagram illustrating an example of a manufacturing method.

[0060] Figure 47 is a diagram illustrating an example of a manufacturing method.

[0061] Figure 48 is a diagram illustrating an example of a manufacturing method. DETAILED DESCRIPTION

[0062] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that in the following examples, identical elements are represented by identical reference numerals, and redundant descriptions may be omitted. Different meanings between different examples may use the same reference numerals, and in this case, may be interpreted according to the description in the examples.

[0063] The present disclosure will be described according to the following item order.

[0064] 0. Example of Photodetector

[0065] 1. First Implementation

[0066] 2. Second Implementation

[0067] 3. Third Implementation

[0068] 4. Fourth embodiment

[0069] 5. Conclusion

[0070] 0. Example of Photodetector

[0071] One of the disclosed technologies is a photodetector. Hereinafter, the case where the photodetector is an imaging device will be described as an example. Note that the terms "imaging" and "image" in the context of an imaging device should be understood to encompass both imaging and video, as long as they are not contradictory, and these terms should be interpreted appropriately.

[0072] Figure 1 is a diagram illustrating an example of a schematic configuration of a photodetector 100. The photodetector 100 includes a pixel array section 1, a vertical drive section 101, a column signal processing section 102, and a control section 103. For convenience, the XYZ system of the pixel array section 1 is also illustrated. The X-axis and Y-axis directions (XY plane directions) correspond to the array directions. The X-axis direction is also referred to as the horizontal direction, the row (line) direction, etc. The Y-axis direction is also referred to as the vertical direction, the column direction, etc.

[0073] The pixel array unit 1 includes a plurality of pixels 2. A plurality of pixels 2 are arranged in a two-dimensional manner (e.g., a two-dimensional grid shape) in the row direction and the column direction. The pixel 2 includes a photoelectric conversion unit, and generates and outputs a voltage signal according to the amount of incident light. The output voltage signal is called a pixel signal. The pixel 2 also includes a circuit (pixel circuit) for receiving light for the photoelectric conversion unit, converting it into a voltage signal, etc. The pixel signal from the pixel 2 is transmitted to the column signal processing unit 102 via a signal line VL.

[0074] The vertical drive section 101 is connected to the pixel array section 1 via signal lines HL. For each row of the pixel array section 1, one or more signal lines HL extend from the vertical drive section 101 into the pixel array section 1 and are commonly connected to the pixels 2 located in the same row. The vertical drive section 101 supplies control signals to the corresponding pixels 2 via the signal lines HL.

[0075] The column signal processing section 102 is connected to the pixel array section 1 via a signal line VL. For each column of the pixel array section 1, one signal line VL extends from the column signal processing section 102 into the pixel array section 1 and is commonly connected to the pixels 2 located in the same column. The column signal processing section 102 processes the image signal from each pixel 2 in each column of the pixel array section 1. Examples of this processing include analog-to-digital (AD) conversion processing. The processed image signal is output as an image signal.

[0076] The control section 103 controls the entire photodetector 100. For example, the control section 103 generates a control signal for controlling the vertical drive section 101 and supplies the control signal to the vertical drive section 101. The signal line used for this purpose is referred to as signal line L31 in the drawings. Furthermore, the control section 103 generates a control signal for controlling the column signal processing section 102 and supplies the control signal to the column signal processing section 102. The signal line used for this purpose is referred to as signal line L32 in the drawings.

[0077] Figure 2 is a diagram illustrating an example of a circuit configuration of pixel 2. In this example, three signal lines HL are connected to pixel 2. The signal lines HL are referred to as signal line HL_TR, signal line HL_RST, and signal line HL_SEL in the drawing so that the signal lines HL can be distinguished from each other. A power supply line Vdd is also shown.

[0078] The pixel 2 includes a photoelectric conversion unit 21 and a pixel circuit. As components of the pixel circuit, the charge holding unit 22 and transistors 23 to 26 are exemplified. Here, it is assumed that each of the transistors 23 to 26 is a FET (field effect transistor). The FET may be a MOSFET.

[0079] In the following description, the drain and source of a transistor are also referred to as current terminals. The gate is also called a control terminal. Connecting a transistor between two components means that one current terminal (one of the drain and source) is connected to one component, and the other current terminal (the other of the drain and source) is connected to the other component.

[0080] The photoelectric conversion portion 21 generates and accumulates electric charge according to the amount of light received. The photoelectric conversion portion 21 shown is a photodiode with a grounded anode.

[0081] The charge holding portion 22 holds the charge accumulated in the photoelectric conversion portion 21. Examples of the charge holding portion 22 include a floating diffusion capacitance, a capacitor, and the like.

[0082] The transistor 23 is a transfer transistor connected between the photoelectric conversion unit 21 and the charge retention unit 22, and transfers the charge accumulated in the photoelectric conversion unit 21 to the charge retention unit 22. The control terminal of the transistor 23 is connected to the signal line HL_TR. The conduction and cutoff (conduction state and non-conduction state) of the transistor 23 are controlled by a control signal from the signal line HL_TR.

[0083] Transistor 24 is a reset transistor connected between charge retention unit 22 and power supply line Vdd, and discharges the charge in charge retention unit 22 to power supply line Vdd. The control terminal of transistor 24 is connected to signal line HL_RST. Transistor 24 is turned on and off by a control signal from signal line HL_RST. Note that by turning on transistor 23, transistor 24 is also connected to photoelectric converter 21, allowing the charge accumulated in photoelectric converter 21 to be discharged to power supply line Vdd.

[0084] The transistor 25 is connected between the power supply line Vdd and the transistor 26. The control terminal of the transistor 25 is connected to the charge holding section 22. The transistor 25 outputs a voltage corresponding to the amount of charge held by the charge holding section 22 (ie, the amount of charge generated in the photoelectric conversion section 21).

[0085] Transistor 26 is a select transistor connected between transistor 25 and signal line VL, and selectively causes the output voltage of transistor 25 to appear on signal line VL. The voltage appearing on signal line VL is a pixel signal. A control terminal of transistor 26 is connected to signal line HL_SEL. Transistor 26 is turned on and off by a control signal from signal line HL_SEL.

[0086] Figure 3 : is a diagram showing an example of a schematic configuration of the pixel array unit 1. A cross section of a portion of the pixel array unit 1 in a side view (as viewed in the X-axis direction or the Y-axis direction) is schematically shown. The pixel array unit 1 includes a semiconductor substrate 3, a fixed charge film 4, an insulating layer 5, an optical layer 6, a wiring layer 7, an insulating layer 8, and a supporting substrate 9. The plane directions of the substrate, the film, and the layer correspond to the XY plane directions (X-axis direction and Y-axis direction), and the thickness direction corresponds to the Z-axis direction. The positive direction of the Z-axis can be referred to as an upward direction, etc. The negative direction of the Z-axis can be referred to as a downward direction, etc. Note that the layers and films can be read with respect to each other within a range where there is no contradiction.

[0087] It should be noted that Figure 3 The portion shown on the right side of is an effective area where pixels 2 including photoelectric conversion units 21 are arranged. Figure 3The portion shown on the left side is an inactive area (an area outside the active area) where no such pixels 2 are arranged. Light incident on the pixel array section 1 is referred to as incident light and is schematically represented by an outline arrow. It is assumed that the incident light propagates downward (in the negative direction of the Z axis).

[0088] At least a portion of the components of the circuit of the pixel 2 is formed on the semiconductor substrate 3. Examples of the material of the semiconductor substrate 3 include Si, SiGe, and InGaAs. Figure 3 The photoelectric conversion unit 21 is shown in FIG.

[0089] The upper surface of the semiconductor substrate 3 (the surface on the positive side of the Z axis) is referred to as the upper surface 3a in the drawings. In the drawings, the lower surface of the semiconductor substrate 3 (the surface on the negative side of the Z axis) is referred to as the lower surface 3b. Light incident on the pixel array unit 1 enters the semiconductor substrate 3 from the upper surface 3a of the semiconductor substrate 3 and reaches the photoelectric conversion unit 21. In addition, since the wiring layer 7 described later is provided on the lower surface 3b of the semiconductor substrate 3, it can be said that the lower surface 3b of the semiconductor substrate 3 is the front side of the semiconductor substrate 3, and the upper surface 3a of the semiconductor substrate 3 is the back side of the semiconductor substrate 3. Photodetector 100 ( Figure 1 ) can also be called a back-illuminated photodetector, imaging device, etc.

[0090] The photoelectric conversion unit 21 will be described further. In this embodiment, the photoelectric conversion unit 21 is formed over substantially the entire region in the thickness direction (Z-axis direction) of the semiconductor substrate 3. The photoelectric conversion unit 21 is, for example, a pn junction type photodiode (PD) including an n-type semiconductor region and a p-type semiconductor region formed to face the upper surface 3a and the lower surface 3b of the semiconductor substrate 3.

[0091] The p-type semiconductor region also serves as a hole charge accumulation region for suppressing dark current. Each pixel 2 is separated by a separation region 31. The separation region 31 is formed of a p-type semiconductor region and is, for example, grounded. The above configuration is configured by forming an n-type source region and a drain region in a p-type semiconductor well region formed on the lower surface 3b side of the semiconductor substrate 3 and forming a gate electrode on the lower surface 3b of the semiconductor substrate 3 between the source region and the drain region via a gate insulating film. Figure 2 Transistors 23 to 26 are described.

[0092] On the upper surface 3a of the semiconductor substrate 3, the fixed charge film 4, the insulating layer 5 and the optical layer 6 are provided in this order.

[0093] The fixed charge film 4 has a negative fixed charge due to the oxygen dipole and plays a role in enhancing pinning. Examples of the material of the fixed charge film 4 are oxides or nitrides. The oxides or nitrides may contain at least one of Hf, Al, zirconium, Ta, and Ti. In addition, the oxides or nitrides may contain at least one of lanthanum, cerium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, thulium, ytterbium, lutetium, and yttrium. Another embodiment of the material of the fixed charge film 4 is hafnium oxynitride or aluminum oxynitride, etc. Silicon or nitrogen can be added to the fixed charge film 4 in an amount that does not impair the insulating properties. Heat resistance, etc. can be improved. By controlling the film thickness or multi-layer stacking, the fixed charge film 4 can be configured to also serve as a reflection suppression film for a semiconductor substrate 3 such as a Si substrate with a high refractive index.

[0094] The insulating layer 5 insulates the semiconductor substrate 3 and the fixed charge film 4 from the optical layer 6 and protects the semiconductor substrate 3 and the fixed charge film 4. In this example, the insulating layer 5 includes an insulating film 51, a light shielding film 52, and an insulating film 53. Examples of the material of the insulating film 51 and the insulating film 53 are SiO2 and the like.

[0095] The insulating film 51 is also a base layer for providing the light shielding film 52 thereon.

[0096] The light-shielding film 52 is provided on the insulating film 51. The light-shielding film 52 is arranged in the boundary area between adjacent pixels 2 (photoelectric conversion parts 21) and blocks stray light leaked from adjacent pixels 2. The light-shielding film 52 includes a material that blocks light. A material having strong light-shielding properties and capable of being accurately processed by micromachining (e.g., etching) can be used. Examples of materials include metal materials such as Al, W, and copper. The light-shielding film 52 can be formed by a metal film containing such a metal material. In addition, silver, gold, platinum, molybdenum, chromium, titanium, nickel, iron, tellurium, etc., and alloys containing these, etc. can be used as materials for the light-shielding film 52. A plurality of these materials can be stacked. In order to improve adhesion to the underlying insulating film 51, a barrier metal (e.g., titanium, tantalum, tungsten, cobalt, molybdenum, alloys thereof, nitrides thereof, oxides thereof, or carbides thereof) can be provided below the light-shielding film 52.

[0097] The light shielding film 52 can also be used as a light shield for pixels that determine an optical black level, or can also be used as a light shield for preventing noise from reaching the peripheral circuit area. The light shielding film 52 is preferably grounded so that it is not damaged by plasma damage caused by accumulated charges during processing. The grounding structure can be formed in the pixel array, but can be grounded in an area outside the active area of ​​the pixel 2 after all conductors are electrically connected, such as Figure 3 shown on the left.

[0098] The insulating film 53 is provided so as to cover the insulating film 51 and the light shielding film 52. The insulating film 53 also plays a role of planarization.

[0099] In this example, the optical layer 6 is provided so as to cover the photoelectric conversion section 21 of the semiconductor substrate 3 with the fixed charge film 4 and the insulating layer 5 interposed therebetween. Figure 3 A plurality of pillars 62 are shown in FIG. The details of the optical layer 6 will be described later.

[0100] On the lower surface 3b of the semiconductor substrate 3, the wiring layer 7, the insulating layer 8 and the support substrate 9 are provided in this order.

[0101] The wiring layer 7 transmits image signals generated by the pixels 2. In addition, the wiring layer 7 also transmits signals applied to the circuits of the pixels 2. Specifically, the wiring layer 7 constitutes the signal line HL and the power supply line Vdd ( Figure 1 and Figure 2 ). The wiring layer 7 and the circuit are connected via a through-hole plug. Furthermore, the wiring layer 7 includes multiple layers, and each layer of the wiring layer is also connected via a via plug. Examples of the material of the wiring layer 7 are metal materials such as Al or Cu. Examples of the material of the via plug include metal materials such as W and Cu. For insulation of the wiring layer 7, for example, a silicon oxide film or the like is used.

[0102] The insulating layer 8 insulates the wiring layer 7 from the supporting substrate 9. Various known materials can be used.

[0103] During the manufacturing process of the pixel array unit 1, the support substrate 9 reinforces and supports the semiconductor substrate 3 and the like. Examples of materials for the support substrate 9 include silicon. The support substrate 9 can be bonded to the semiconductor substrate 3 using plasma bonding or an adhesive material. The support substrate 9 can be configured to include logic circuits. By forming connection vias between the substrates, various peripheral circuit functions can be stacked vertically, reducing chip size.

[0104] The optical layer 6 will be further described. The optical layer 6 controls the phase of incident light, etc. The optical layer 6 may also be referred to as a light control portion, an optical phase control portion, etc.

[0105] Figure 4 and Figure 5 : is a diagram showing an example of a schematic configuration of the optical layer 6. Note that, Figure 5 A cross section of a portion including the pillars 62 of the optical layer 6 is schematically shown in a plan view (when viewed in the Z-axis direction).

[0106] The optical layer 6 includes a reflection-reducing film 61, a plurality of pillars 62, a reflection-reducing film 63, a filler 64, and a protective film 65. The upper and lower surfaces of the reflection-reducing film 61 are referred to as upper surface 61a and lower surface 61b in the drawings. The upper and lower surfaces of the pillars 62 are referred to as upper surface 62a and lower surface 62b in the drawings. The upper and lower surfaces of the reflection-reducing film 63 are referred to as upper surface 63a and lower surface 63b in the drawings.

[0107] The reflection-reducing film 61 is provided between the pillar 62 and the insulating layer 5, more specifically, on the insulating layer 5 and on the lower surface 62b of the pillar 62. The upper surface 61a of the reflection-reducing film 61 is in surface contact with the lower surface 62b of the pillar 62 and the filler 64. This surface serves as a refractive index boundary surface between the reflection-reducing film 61 and the pillar 62, and also serves as a refractive index boundary surface between the reflection-reducing film 61 and the filler 64.

[0108] The reflection-suppressing film 61 suppresses light reflection from the lower surface 62b of the pillar 62 and its vicinity. For example, the reflection-suppressing film 61 has a refractive index between that of the insulating layer 5 and that of the pillar 62. Assuming that the wavelength of light to be detected in the medium is λ, the thickness of the reflection-suppressing film 61 can be λ / 4n (where n is the refractive index of the medium) or an integer multiple thereof. By providing this reflection-suppressing film 61, light reflection from the lower surface 62b of the pillar 62 and its vicinity can be suppressed. Examples of materials for the reflection-suppressing film 61 include SiN and the like.

[0109] The pillars 62 are fine structures having a size shorter than the wavelength of incident light (more specifically, detection target light). The pillars 62 are processed into a columnar shape or a columnar-based shape and extend in the thickness direction of the optical layer 6. Examples of the material of the pillars 62 are amorphous silicon and the like.

[0110] The plurality of pillars 62 are arranged side by side at intervals, for example, in the plane direction of the optical layer 6 to guide the light to be detected among the incident light to the photoelectric conversion section 21 ( Figure 3 ). The light to be detected may be visible light or invisible light. Examples of visible light include red light, green light, and blue light. Examples of invisible light include infrared light (IR) and the like, and more specifically, near infrared light (NIR).

[0111] The plurality of pillars 62 impart an optical function to the optical layer 6. Examples of optical functions include a function for controlling the direction of light, more specifically, a prism function, a lens function, and the like. The prism function is a function for separating light contained in incident light for each wavelength and guiding (or directing) light to be detected in the light to the photoelectric converter 21, and may also be referred to as a spectrometer function, a color separation function, a filter function, or the like. The lens function is a function for focusing light onto the photoelectric converter 21 (a light-concentrating function).

[0112] Each pillar 62 is designed to provide a local phase difference in light passing through the optical layer 6. Examples of the design of the pillar 62 include the design of the size of the pillar 62, the design of the shape of the pillar 62, the design of the arrangement of the pillar 62, and the like. Examples of the size of the pillar 62 include the width of the pillar 62 (the length in the X-axis direction, the length in the Y-axis direction), the height of the pillar 62 (the length in the Z-axis direction), and the like. Examples of the shape of the pillar 62 include the shape when the pillar 62 is observed in a plan view (when viewed in the Z-axis direction), the shape when the pillar 62 is observed in a side view (when viewed in the X-axis direction and the Y-axis direction), and the like. The shape may be a cross-sectional shape. The arrangement of the pillar 62 is the planar layout of the pillar 62, and includes, for example, the spacing between adjacent pillars 62 (pillar spacing).

[0113] For example, if the pillars 62 have a higher refractive index than the surrounding area (e.g., the refractive index of the filler 64), the effective refractive index of the portion with a larger proportion of the pillars 62 becomes higher, and the effective refractive index of the portion with a smaller proportion of the pillars 62 becomes lower. The phase of light passing through the portion with a high effective refractive index is delayed compared to the phase of light passing through the portion with a low effective refractive index. By varying the amount of phase delay of light, the direction of light can be controlled.

[0114] The reflection suppression film 63 is provided on the upper surface 62a of the pillar 62. The lower surface 63b of the reflection suppression film 63 is in surface contact with the upper surface 62a of the pillar 62. This surface serves as a refractive index boundary surface between the reflection suppression film 63 and the pillar 62.

[0115] The reflection-suppressing film 63 suppresses light reflection from the upper surface 62a of the pillar 62 and its vicinity. For example, the reflection-suppressing film 63 has a refractive index between that of the pillar 62 and that of the upper region of the reflection-suppressing film 63 (in this example, the filler 64). The thickness of the reflection-suppressing film 63 can be λ / 4n (n is the refractive index of the medium) or an integer multiple thereof. By providing such a reflection-suppressing film 63, light reflection from the upper surface 62a of the pillar 62 and its vicinity can be suppressed. An example of a material for the reflection-suppressing film 63 is SiN, etc. The reflection-suppressing film 63 can be a low-temperature oxide film (LTO film, e.g., a silicon oxide film), etc.

[0116] The filler 64 is provided to fill the gaps between the pillars 62 and to cover the reflection-inhibiting film 61, the pillars 62, and the reflection-inhibiting film 63. This can suppress pillar collapse (collapse of the pillars 62) and can also suppress tape residue during assembly. Examples of materials for the filler 64 include resins and the like. The refractive index of the filler 64 can be lower than that of each of the reflection-inhibiting film 61, the pillars 62, and the reflection-inhibiting film 63. For example, the filler 64 is in surface contact with the upper surface 63 a of the reflection-inhibiting film 63, and this surface serves as a refractive index boundary surface between the filler 64 and the reflection-inhibiting film 63.

[0117] The protective film 65 is disposed on the filler 64. For example, when the PAD photoresist of the PAD opening is stripped in a subsequent process, the filler 64 can be prevented from being damaged. The material of the protective film 65 can be an inorganic material, such as SiO2. In this case, the protective film 65 can also be referred to as an inorganic protective film.

[0118] Taking into account the refractive index and wavelength of the light to be detected, the thickness of the portion of the filler 64 located between the pillar 62 (more specifically, the reflection suppression film 63) and the protective film 65, and the thickness of the protective film 65 can be designed so that the reflected waves cancel each other out as a whole using, for example, the Fresnel coefficient method.

[0119] Note that filler 64 can be omitted. In this case, for example, the surrounding material of reflection-reducing film 61, support 62, and reflection-reducing film 63 can be air (air region). Filler 64 can be appropriately interpreted as surrounding material, air (air region), or the like, as long as there is no conflict. Furthermore, protective film 65 may not be provided.

[0120] In the optical layer 6 having the above configuration, since the pillars 62 are fine structures, there is a possibility that pillar collapse may occur. Specific techniques for suppressing pillar collapse will be described as first to fourth embodiments described below.

[0121] 1. First Implementation

[0122] In the first embodiment, the shape of the support column 62 is designed to suppress the column collapse.

[0123] Figure 6 and Figure 7 is a diagram showing an example of a schematic configuration of the support column 62 and its peripheral structure. Figure 6 A cross section in a side view (as viewed in the X-axis direction or the Y-axis direction) is schematically shown. Figure 7The schematic diagram shows a planar layout in a plan view (as viewed in the negative Z-axis direction). In this example, the reflection suppression film 63 and the LTO film 66 are provided so as to cover the upper surface 62a of the pillar 62. Specifically, the reflection suppression film 63 is provided on the upper surface 62a of the pillar 62, and the LTO film 66 (for example, a silicon oxide film) is further provided thereon.

[0124] The side surface of support 62 is referred to as side surface 62c in the drawings. At least a portion of side surface 62c has a curved surface that bulges outward from support 62. Alternatively, support 62 can be said to have a convex portion. Specifically, support 62 includes an upper end 621, a lower end 622, and a middle portion 623.

[0125] The upper end portion 621 is the portion that includes the upper surface 62a of the support column 62. The lower end portion 622 is the portion that includes the lower surface 62b of the support column 62. The intermediate portion 623 is located between the upper end portion 621 and the lower end portion 622. At least a portion of the intermediate portion 623 has a width greater than the width (length in the XY plane) of either the upper end portion 621 or the lower end portion 622. When viewed from the height direction of the support column (the Z-axis direction), at least a portion of the intermediate portion 623 has a cross-sectional area greater than the area of ​​either the upper surface 62a or the lower surface 62b of the support column 62.

[0126] When the pillar 62 is viewed in a plan view, the reflection suppression film 63 is located on the inner side of the pillar 62. Similarly, the LTO film 66 is located on the inner side of the pillar 62. For example, Figure 7 As shown, when the pillar 62 is viewed from above (viewed in the negative Z-axis direction), a portion of the pillar 62 appears outside the LTO film 66 .

[0127] The filler 64 is provided to fill the spaces between the plurality of pillars 62. In this example, the filler 64 is provided to fill the spaces between adjacent pillars 62 and to cover the reflection-reducing film 61, the pillars 62, the reflection-reducing film 63, and the filler 64. The filler 64 is in contact with at least the side surfaces 62c of the pillars 62. Because the side surfaces 62c of the pillars 62 bulge outward, for example, compared to a case where the side surfaces 62c are straight, the filler 64 is more easily caught by the pillars 62 and less likely to peel off from the pillars 62 (also known as a hook effect, etc.). This increases the likelihood of suppressing pillar collapse.

[0128] Furthermore, the fact that the cross-sectional area of ​​the middle portion 623 of the pillar 62 is larger than that of the upper surface 62a means that a thickness (width or cross-sectional area) exceeding the limit of photolithography is imparted to the pillar 62. The effective line width can be adjusted by thickening the pillar 62.

[0129] In one embodiment, the side surface 62c of the pillar 62 may further have an inwardly concave curved surface. Figure 8 Provide a description.

[0130] Figure 8 62 and its peripheral structure. The support 62 includes two intermediate portions 623. The first intermediate portion 623 is referred to as intermediate portion 623-1 in the figure. The second intermediate portion 623 is referred to as intermediate portion 623-2 in the figure.

[0131] As described above, the width of the middle portion 623-1 is greater than the width of each of the upper end portion 621 and the lower end portion 622, and has a cross-sectional area greater than the area of ​​each of the upper surface 62a and the lower surface 62b of the pillar 62. The middle portion 623-2 may have a width smaller than the width of at least one of the upper end portion 621 and the lower end portion 622 (the lower end portion 622 in this example), and may have a cross-sectional area smaller than the area of ​​at least one of the upper surface 62a and the lower surface 62b of the pillar 62 (the lower surface 62b in this example).

[0132] Since the side surface 62c of the pillar 62 has not only an outwardly convex curved surface but also an inwardly concave curved surface, the filler 64 is more easily caught on the pillar 62. The filler 64 is further peeled off from the pillar 62, and the effect of suppressing the collapse of the pillar is further enhanced.

[0133] Figures 9 to 13 is a diagram illustrating an embodiment of a manufacturing method. The material of the reflection-reducing film 61 is referred to as a reflection-reducing film material 61m. The material of the pillar 62 is referred to as a pillar material 62m. The material of the reflection-reducing film 63 is referred to as a reflection-reducing film material 63m. The material of the LTO film 66 is referred to as an LTO film material 66m.

[0134] like Figure 9 As shown in FIG, a pillar material 62m is formed on the reflection suppression film material 61m. The reflection suppression film material 61m is, for example, SiN, and serves as a stopper. The pillar material 62m is, for example, amorphous silicon having a higher refractive index.

[0135] like Figure 10 As shown, the reflection suppression film material 63m is formed on the pillar material 62m.

[0136] like Figure 11As shown, an LTO film material 66m is formed on a reflection suppression film material 63m, and a mask M is also provided thereon. The mask M may have a laminated structure in which a plurality of masks are laminated. A photoresist PR (e.g., ArF resist) having a pattern matching the columnar shape is formed on the mask M. In this example, the photoresist PR has a tapered shape in which the cross-sectional area (as viewed in the Z-axis direction) decreases with distance from the mask M.

[0137] like Figure 12 As shown, the pillar material 62m, the reflection suppressing film material 63m, and the LTO film material 66m are processed by dry etching. As a result, the pillar 62 is obtained, which includes the middle portion 623 (in this example, the middle portion 623-1 and the middle portion 623-2) and the reflection suppressing film 63 and the LTO film 66 provided thereon in sequence.

[0138] like Figure 13 As shown, the filler 64 is provided to fill the spaces between the plurality of pillars 62 , more specifically, to cover the reflection suppression film 61 , the pillars 62 , the reflection suppression film 63 , and the filler 64 .

[0139] <Partial Overview>

[0140] For example, the technology according to the first embodiment described above is defined as follows. One of the disclosed technologies is a photodetector 100. Figures 1 to 8 As described in [ 15 ], the photodetector 100 includes a photoelectric conversion portion 21 and an optical layer 6 arranged to cover the photoelectric conversion portion 21. The optical layer 6 includes a plurality of pillars 62 arranged side by side in the plane direction of the layer (XY plane direction) so as to guide at least the light to be detected among the incident light to the photoelectric conversion portion 21; and a filler 64 arranged to fill the space between the plurality of pillars 62. The side surface 62c of the pillar 62 has a curved surface that is convex toward the outside of the pillar 62. Therefore, the filler 64 is easily captured by the pillar 62, and the filler 64 is hardly peeled off from the pillar 62. Therefore, the pillar collapse can be suppressed.

[0141] See Figure 6 、 Figure 7As described in [ 15 ] and [ 16 ], the pillar 62 may include an upper end portion 621 having an upper surface 62a of the pillar 62, a lower end portion 622 having a lower surface 62b of the pillar 62, and an intermediate portion 623 located between the upper end portion 621 and the lower end portion 622 and having a width greater than that of either the upper end portion 621 or the lower end portion 622. The intermediate portion 623 may have a cross-sectional area greater than either the upper surface 62a or the lower surface 62b. The optical layer 6 includes a film (a reflection suppression film 63 and an LTO film 66) disposed to cover the upper surface 62a of the pillar 62, and when the pillar 62 is viewed in a plan view (when viewed in the negative Z-axis direction), the film may be located inside the pillar 62. For example, by using a pillar 62 having such a configuration, pillar collapse can be suppressed.

[0142] As reference Figure 8 As described in

[15] , the side surface 62c of the pillar 62 may further have a curved surface that is concave toward the inside of the pillar 62. The filler 64 is more easily caught by the pillar 62, and collapse of the pillar can be further suppressed.

[0143] 2. Second Implementation

[0144] In the second embodiment, the shape of the reflection-reducing film 61 is designed to suppress the collapse of the pillars.

[0145] Figure 14 is a diagram illustrating an example of a schematic configuration of the optical layer 6. The reflection-reducing film 61 includes a plurality of upper end portions 611, a lower end portion 612, and a plurality of intermediate portions 613 corresponding to the upper end portions 611. Each of the upper end portions 611 is located on the lower surface 62b of the corresponding pillar 62 and is a portion having the upper surface 61a of the reflection-reducing film 61. The lower end portion 612 is a portion having the lower surface 61b of the reflection-reducing film 61. Each of the intermediate portions 613 is a portion located between the corresponding upper end portion 611 and lower end portion 612.

[0146] The side surface of the reflection-reducing film 61, more specifically, the side surface of the upper end portion 611 and a portion of the middle portion 613, is referred to as a side surface 61c in the drawings. At least a portion of the side surface 61c has a curved surface that is concave toward the inside of the reflection-reducing film 61. Alternatively, it can be said that the side surface of the reflection-reducing film 61 has a concave portion.

[0147] The width of the middle portion 613 is smaller than the width of either the upper end portion 611 or the lower end portion 612. The cross-sectional area of ​​the middle portion 613 is smaller than any of the upper surface 61a and the lower surface 61b of the reflection suppression film 61.

[0148] The depression dp is formed at the interface between the upper surface 61a of the reflection-reducing film 61 and the lower surface 62b of the pillar 62. The filler 64 is provided to fill the spaces between the plurality of pillars 62 and to cover the reflection-reducing film 61. The depression dp is filled with the filler 64. The filler 64 is easily captured by the pillar 62 and is unlikely to peel off from the pillar 62. This increases the likelihood of suppressing the collapse of the pillar.

[0149] Figure 15 and Figure 16 It is a diagram showing an example of a manufacturing method. As a premise, it is assumed that Figure 10 The process has been completed.

[0150] like Figure 15 As shown, the LTO film material 66m is formed on the reflection suppression film material 63m, and a mask M is also provided thereon. On the mask M, a photoresist PR (for example, ArF resist) having a pattern matching the columnar shape is formed.

[0151] like Figure 16 As shown, the pillar material 62m, the reflection-reducing film material 63m, and the LTO film material 66m are processed by dry etching. A recess dp is generated during the dry etching process. As a result, a reflection-reducing film 61 including a plurality of upper end portions 611, a lower end portion 612, and a plurality of intermediate portions 613 is obtained, along with a plurality of pillars 62, a reflection-reducing film 63, and an LTO film 66, each sequentially disposed on the corresponding upper end portion 611.

[0152] Thereafter, the above-mentioned Figure 14 structure.

[0153] Summary

[0154] For example, the technology according to the second embodiment described above is defined as follows. One of the disclosed technologies is a photodetector 100. Figures 1 to 5 、 Figure 14As described in [ 14 ] and others, the photodetector 100 includes a photoelectric converter 21 and an optical layer 6 arranged to cover the photoelectric converter 21. The optical layer 6 includes a plurality of pillars 62 arranged side by side in the layer's plane direction (XY plane direction) to guide at least the light to be detected of the incident light toward the photoelectric converter 21; a reflection-reducing film 61 provided on the lower surface 62b of the pillars 62; and a filler 64 provided to fill the spaces between the plurality of pillars and cover the reflection-reducing film 61. The reflection-reducing film 61 is located on the lower surface 62b of the pillars 62 and includes an upper end portion 611 having the upper surface 61a of the reflection-reducing film 61, a lower end portion 612 having the lower surface 61b of the reflection-reducing film 61, and an intermediate portion 613 located between the upper and lower ends 611 and having a width smaller than that of the upper end portion 611. Therefore, the filler 64 is easily captured by the pillars 62 and is less likely to peel off from the pillars 62. Consequently, collapse of the pillars can be suppressed.

[0155] As reference Figure 14 As described in [ 15 ], the side surface 61 c of the reflection-reducing film 61 may have an inwardly concave curved surface. A concavity dp may be formed at the interface between the upper surface 61 a of the reflection-reducing film 61 and the lower surface 62 b of the pillar 62, and the concavity dp may be filled with a filler 64. For example, with such a configuration, the filler 64 can be easily caught by the pillar 62, and collapse of the pillar can be suppressed.

[0156] 3. Third Implementation

[0157] In the third embodiment, by covering the side surfaces 62 c of the pillars 62 with a film, pillar collapse is suppressed.

[0158] Figure 17 is a diagram illustrating an example of a schematic configuration of the optical layer 6. The optical layer 6 includes a film 67. The film 67 is provided to cover at least the side surfaces 62c of the pillars 62. In this example, the film 67 is provided on the side surfaces 62c of the pillars 62. The film 67 can also be provided to cover the upper surfaces 62a of the pillars 62. In this example, the film 67 is provided on the upper surface of the LTO film 66, covering the upper surfaces 62a of the pillars 62 with the reflection suppression film 63 and the LTO film 66 interposed therebetween. A filler 64 is provided to fill the spaces between the plurality of pillars 62 and to cover the film 67.

[0159] The film 67 may be, for example, a transparent insulating film. Since the pillars 62 are covered with the film 67, the pillars 62 are less likely to fall than when they are not covered. Therefore, the pillars can be prevented from collapsing.

[0160] Figure 18 It is a diagram showing an example of a manufacturing method. As a premise, it is assumed that Figure 15 The process is completed. Figure 18As shown, the pillar material 62m, the reflection suppression film material 63m and the LTO film material 66m are processed by dry etching to obtain the pillar 62, the reflection suppression film 63 and the LTO film 66. For example, a film 67 is formed to cover them using atomic layer deposition (ALD). By providing a filler 64 to fill the space between the plurality of pillars 62 and to cover the film 67, a Figure 17 The above structure.

[0161] The further technical significance of covering the pillars 62 with the film 67 will be described. First, since the pillars can be suppressed from collapsing as described above, the design rules for the pillars 62 can be relaxed accordingly. For example, the design of the pillars 62 with a smaller width (which can be a cross-sectional area) can be realized. Therefore, the difference in effective refractive index between each pillar 62 and its surrounding area can be increased, and the desired optical characteristics can be easily obtained. In addition, the film 67 can be used as a reflection suppression film.

[0162] Will refer to Figure 19 and Figure 20 The relationship between covering the pillars 62 with the film 67 and the effective refractive index is described.

[0163] Figure 19 and Figure 20 is a diagram showing an example of the effective refractive index. Figure 19 The support 62 and membrane 67 are schematically shown in a plan view (as viewed in the Z-axis direction). In this example, the support 62 has a circular cross-sectional shape. The membrane 67 has a ring-shaped cross-sectional shape with the support 62 inside. The distance between the support pillars is referred to as support distance P in the drawings. The radius of the support pillar 62 is referred to as radius r in the drawings. The thickness of the membrane 67 is referred to as thickness dr in the drawings.

[0164] The refractive index of the pillar 62 is referred to as refractive index n1. The refractive index of the film 67 is referred to as refractive index n2. The refractive index of the filler 64 is referred to as refractive index n0. Assume that the effective refractive index within the range of the pillar pitch P is the effective refractive index n1. eff , then the effective refractive index n eff It is represented by the following formula (1). As will be understood, the larger the initial diameter (radius r of the pillar 62), the greater the effective refractive index n eff The higher.

[0165]

[0166] In addition, the area I inner The inner second moment and area I outer The outer second moment of is expressed by the following formulas (2) and (3). It can be understood that even when the original diameter is small, the area second moment increases.

[0167]

[0168] exist Figure 20 In (A), the effective refractive index n is shown with respect to the radius r by a graph. eff In the embodiment of Figure 20 In (B), the effective refractive index n eff An example of the range is shown in the graph. The refractive index n0 of the filler 64 is 1.4. The refractive index n1 of the pillar 62 is 3.6. The pillar spacing P is 350 nm. Note that the thickness dr=0 means that there is no film 67. Figure 20 As shown in (A), the effective refractive index n eff As the radius r of the support 62 increases. Figure 20 As shown in (B), the effective refractive index n can be increased by increasing the thickness dr of the film 67 or increasing the refractive index n2. eff range.

[0169] Various designs are possible. Some examples are described as Examples 1 to 12 below.

[0170] First, refer to Figure 21 The configuration common to Examples 1 to 3 is described.

[0171] Figure 21 is a diagram illustrating an example of a schematic configuration of the optical layer 6. Two adjacent pillars 62 among a plurality of pillars 62 are illustrated. In the figure, the pillar 62 having a relatively small width is referred to as pillar 62-1. The pillar 62 having a relatively large width is referred to as pillar 62-2. Unless otherwise specified, they are simply referred to as pillars 62.

[0172] The reflection suppression film 63 and the LTO film 66 described above are not provided on the upper surface 62a of the pillar 62. The film 67 is provided on the side surface 62c so as to cover the side surface 62c of the pillar 62. The film 67 does not cover the upper surface 62a of the pillar 62, and does not cover the upper surface 61a of the reflection suppression film 61.

[0173] An example of a manufacturing method will be described. After processing the pillar 62, a film 67 having high transparency is formed on the side surface 62c of the pillar 62. Thereafter, the film 67 is etched back to remove the film 67 laminated on the upper surface 62a of the pillar 62 and the upper surface 61a of the reflection suppression film 61. Thereafter, the filler 64 is formed in a manner covering the pillar 62. The filler 64 may not be present, and the portion may be a void (air region).

[0174] Figure 22 6 is a diagram showing an example of a planar layout of the pillars 62. Various pillars 62 having different widths are arranged side by side. Each pillar 62 is covered with a film 67.

[0175] In the above Figure 21 and Figure 22 In the configuration shown in , various combinations of materials and refractive indices of the pillars 62, the membrane 67, and the filler 64 are possible. Specific examples will be described as Examples 1 to 3.

[0176] <Example 1>

[0177] In Example 1, the film 67 has a higher refractive index than the filler 64. More specifically, the refractive index n2 of the film 67 is the highest, the refractive index n0 of the filler 64 is the lowest, and the refractive index n1 of the pillar 62 is a value therebetween (n2>n1>n0).

[0178] Examples of materials and refractive indices in the case where the wavelength of light to be detected is 940 nm are as follows.

[0179] Pillar 62: amorphous silicon (a-Si), refractive index n1 = 3.6

[0180] Film 67: Germanium (Ge), refractive index n2 = 4.5

[0181] Filler 64: polymer resin, refractive index n0 = 1.4

[0182] Examples of materials and refractive indices in the case where light to be detected is visible light (red light, green light, and blue light) are as follows.

[0183] Pillar 62: Silicon nitride (Si3N4), refractive index n1 = 2.01 to 2.08

[0184] Film 67: titanium oxide TiO2, refractive index n2 = 2.56 to 2.87

[0185] Filler 64: None (air region). Refractive index n0 = 1.0

[0186] <Example 2>

[0187] In Example 2, the film 67 has the same refractive index as that of the pillars 62. More specifically, the refractive index n2 of the film 67 and the refractive index n1 of the pillars 62 have the same values, and the refractive index n0 of the filler 64 is lower than these values ​​(n2=n1>n0).

[0188] Examples of materials and refractive indices in the case where the wavelength of light to be detected is 940 nm are as follows.

[0189] Pillar 62: amorphous silicon (a-Si), refractive index n1 = 3.6

[0190] Film 67: amorphous silicon (a-Si), refractive index n1 = 3.6

[0191] Filler 64: polymer resin, refractive index n0 = 1.4

[0192] Examples of materials and refractive indices in the case where light to be detected is visible light are as follows.

[0193] Column 62: titanium oxide TiO2, refractive index n2 = 2.56 to 2.87

[0194] Film 67: titanium oxide TiO2, refractive index n2 = 2.56 to 2.87

[0195] Filler 64: None (air region). Refractive index n0 = 1.0

[0196] <Example 3>

[0197] In Example 3, the film 67 has a refractive index lower than that of the pillars 62. More specifically, the refractive index n1 of the pillars 62 is the highest, the refractive index n0 of the filler 64 is the lowest, and the refractive index n2 of the film 67 is a value therebetween (n1>n2>n0).

[0198] Examples of materials and refractive indices in the case where the wavelength of light to be detected is 940 nm are as follows.

[0199] Pillar 62: amorphous silicon (a-Si), refractive index n1 = 3.6

[0200] Film 67: Titanium dioxide TiO2, refractive index n2 = 2.49

[0201] Filler 64: polymer resin, refractive index n0 = 1.4

[0202] Another example is as follows:

[0203] Pillar 62: amorphous silicon (a-Si), refractive index n1 = 3.6

[0204] Film 67: zinc peroxide (ZnO2), refractive index n2 = 2.13

[0205] Filler 64: polymer resin, refractive index n0 = 1.4

[0206] Another embodiment is as follows.

[0207] Pillar 62: amorphous silicon (a-Si), refractive index n1 = 3.6

[0208] Film 67: Hafnium oxide (HfO2), refractive index n2 = 2.02

[0209] Filler 64: polymer resin, refractive index n0 = 1.4

[0210] The cross-sectional shapes of the pillars 62 and membranes 67 can also be designed differently. For example, the cross-sectional shape of the pillar 62-2 can be designed to obtain a larger area of ​​the side surface 62c. By providing more membranes 67 in the pillar 62-2, a larger effective refractive index difference can be obtained between the pillars 62-1 and 62-2. Some specific embodiments will be described as Examples 4 to 6.

[0211] <Example 4>

[0212] Figure 23 62 and the membrane 67. Note that, for reference, Figure 23 (A) shows the pillar 62 before being covered by the membrane 67. Figure 23 In part (B), the pillar 62 is shown as being covered with a film 67. The same applies to the later described Figure 24 and Figure 25 .

[0213] The support 62-1 has a circular cross-sectional shape. A film 67 is provided on a side surface 62c of the support 62-1.

[0214] Pillar 62-2 has an annular cross-sectional shape. More specifically, side surface 62c of pillar 62-2 includes side surface 62co and side surface 62ci. Side surface 62co is the outer side of the annulus. Side surface 62ci is the inner side of the annulus. In this example, membrane 67 includes membrane 67-1 and membrane 67-2. Membrane 67-1 is a first membrane located outside the annular cross-sectional shape and is disposed on side surface 62co. Membrane 67-2 is a second membrane located inside the annular cross-sectional shape and is disposed on side surface 62ci to fill the inner side of the annular shape.

[0215] The annular cross-sectional shape of the pillar 62-2 is larger than the circular cross-sectional shape of the pillar 62-1. Since the amount of the film 67-1 provided on the side surface 62c of the pillar 62-2 is larger than the amount of the film 67 provided on the side surface 62c of the pillar 62-1, a larger effective refractive index difference can be obtained.

[0216] In one embodiment, the thin film 67-2 disposed on the side surface 62ci of the pillar 62-2 may have a higher refractive index than the thin film 67-1 disposed on the side surface 62co. As a result, a greater effective refractive index difference may be obtained.

[0217] <Example 5>

[0218] Figure 24is a diagram illustrating examples of the cross-sectional shapes of pillars 62 and films 67. Pillar 62-1 has a circular cross-sectional shape. Film 67 is provided on side surface 62c of pillar 62-1. Pillar 62-2 has a cross-sectional shape. Since pillar 62-2 has a cross-sectional shape, the area of ​​side surface 62c is larger than that of a pillar with a circular cross-sectional shape, and more films 67 are provided on side surface 62c of pillar 62-2. As a result, a greater effective refractive index difference can be achieved.

[0219] <Example 6>

[0220] Figure 25 6 is a diagram showing an example of the cross-sectional shape of the pillar 62 and the membrane 67. The pillar 62-1 has a cross-sectional shape with a concave-convex periphery. It can be said that the side surface 62c of the pillar 62 has a concave-convex shape, is a concave-convex surface, etc. The pillar 62-2 also has a cross-sectional shape with a concave-convex periphery. Due to the presence of the concave-convex, the area of ​​the side surface 62c increases, and more membranes 67 are provided. However, as the diameter of the pillar 62 increases, this effect becomes more significant. That is, the effect of adding the membrane 67 is greater in the pillar 62-2 than in the pillar 62-1. As a result, a larger effective refractive index difference can be obtained.

[0221] The reflection suppression film 63 can be used in combination with the film 67. The effect of suppressing light reflection can be further enhanced. Some specific examples will be described as Examples 7 and 8.

[0222] <Example 7>

[0223] Figure 26 is a diagram illustrating an example of a schematic configuration of the optical layer 6. A reflection-reducing film 63 is provided on the upper surface 62a of the support 62. The side surface of the reflection-reducing film 63 is referred to as the side surface 63c in the drawings. A film 67 is provided on the side surface 63c so as to also cover (a portion of) the side surface 63c of the upper surface 63a and the side surface 63c of the reflection-reducing film 63. The film 67 has a refractive index higher than that of the reflection-reducing film 63. This maximizes the effect of the reflection-reducing film 63.

[0224] An example of a manufacturing method will be described. Dry etching is performed using the reflection suppressing film 63 as a mask to form the pillars 62. The film 67 is formed and etched back to expose the reflection suppressing film 63. Thereafter, the filler 64 is formed.

[0225] <Example 8>

[0226] Figure 27is a diagram illustrating an example of a schematic configuration of the optical layer 6. A film 67 is also provided on the upper surface 63a and the side surface 63c to cover the upper surface 63a and the side surface 63c of the reflection-suppressing film 63. The film 67 is also provided on the upper surface 61a of the reflection-suppressing film 61. The film 67 has a refractive index lower than that of the reflection-suppressing film 63. By gradually increasing the effective refractive index toward the pillar 62, the effect of suppressing light reflection can be further enhanced.

[0227] An embodiment of a manufacturing method will be described. Dry etching is performed using the reflection suppression film 63 as a mask to form the pillars 62. Thereafter, the film 67 is formed, and further, the filler 64 is formed.

[0228] <Example 9>

[0229] In one example, multiple membranes 67 may be provided. This will be referred to as Figure 28 Provide a description.

[0230] Figure 28 : is a diagram showing an example of a schematic configuration of the optical layer 6. The optical layer 6 includes a plurality of laminated films 67 each having a different refractive index. As the plurality of films 67, Figure 28 67. Each film 67 is referred to as film 67-1, film 67-2, and film 67-3 in the drawings so as to be distinguishable. In the case where they are not particularly distinguished, they are simply referred to as film 67.

[0231] In this example, films 67-1, 67-2, and 67-3 are sequentially laminated in a direction away from the pillar 62. The refractive index of film 67-1 is closest to the refractive index n1 of the pillar 62. The refractive index of film 67-3 is closest to the refractive index n0 of the filler 64. The refractive index of film 67-2 is a value between the refractive index of film 67-1 and the refractive index of film 67-3. Since the plurality of films 67 function as a multilayer reflection suppression film, reflection suppression can be enhanced.

[0232] The plurality of films 67 are obtained by successively forming a film 67 - 1 , a film 67 - 2 , and a film 67 - 3 after forming the pillars 62 .

[0233] <Example 10>

[0234] In one embodiment, the material of the film 67 may include a material having a larger Young's modulus (high Young's modulus material) than the material of the pillar 62. By covering the pillar 62 with such a film 67, the effect of suppressing the collapse of the pillar can be further enhanced.

[0235] Examples of materials, refractive indices, and Young's moduli in the case where the wavelength of light to be detected is 940 nm are as follows.

[0236] Pillar 62: amorphous silicon (a-Si), refractive index n1 = 3.6, Young's modulus = 80 GPa

[0237] Film 67: Alumina Al2O3, refractive index n2 = 1.8, Young's modulus = 300 GPa

[0238] Filler 64: polymer resin, refractive index n0 = 1.4

[0239] Another embodiment is as follows:

[0240] Pillar 62: amorphous silicon (a-Si), refractive index n1 = 3.6, Young's modulus = 80 GPa

[0241] Film 67: titanium oxide TiO2, refractive index n2 = 2.49, Young's modulus = 130 GPa

[0242] Filler 64: polymer resin, refractive index n0 = 1.4

[0243] <Example 11>

[0244] In one embodiment of membrane 67, the contact angle of membrane 67 with the wet cleaning solution used in subsequent processes can be smaller than the contact angle of pillars 62 with the cleaning solution. This can further suppress pillar collapse. The hydrophilicity of the surface of membrane 67 can be increased by ultraviolet irradiation, for example.

[0245] <Example 12>

[0246] By designing the shape of the boundary portion between the reflection suppression film 61 and the pillar 62, it is also possible to suppress the peeling of the film 67 and enhance the effect of suppressing light reflection. Figure 29 and Figure 30 Provide a description.

[0247] Figure 29 is a diagram illustrating an example of a schematic configuration of the optical layer 6. In this example, the optical layer 6 includes a plurality of reflection-reducing films 61, each of which is provided on the lower surface 62b of a corresponding support 62. The side surfaces of the reflection-reducing films 61 are referred to as side surfaces 61c in the drawings. A film 67 is provided on the side surfaces 62c so as to also cover the side surfaces 62c of the reflection-reducing films 61.

[0248] The lower surface 62b of the support 62 and the upper surface 61a of the reflection-reducing film 61 are in surface contact with each other. The lower surface 62b of the support 62 and the upper surface 61a of the reflection-reducing film 61 have different areas. In this example, the area of ​​the upper surface 61a of the reflection-reducing film 61 is smaller than the area of ​​the lower surface 62b of the support 62. Due to the area gap, a constriction C is formed at the boundary surface between the support 62 and the reflection-reducing film 61.

[0249] In this example, the film 67 is provided to fill the constriction C. The constriction C is provided with more films 67 than other portions. That is, the thickness of the portion of the film 67 located in the constriction C is greater than the thickness of the other portions. By providing many films 67, peeling of the film 67 at the interface between the support 62 and the reflection suppression film 61 can be suppressed.

[0250] In addition, by providing more films 67 in a part of the constriction C than in other parts, the effective refractive index can be changed in a stepwise manner, thereby suppressing light reflection. Figure 30 Give a description.

[0251] Figure 30 This is an enlarged view of the constriction C and its surroundings. The effective refractive index of the region where the pillar 62 is located in the Z-axis direction is referred to as the effective refractive index ne1. Furthermore, the effective refractive index of the region where the constriction C is located is referred to as the effective refractive index ne2. Within the region where the reflection-reducing film 61 is located, the effective refractive index of the region other than the region where the constriction C is located is referred to as the effective refractive index ne3. Among these effective refractive indices, the effective refractive index ne1 can be the highest, the effective refractive index ne3 can be the lowest, and the effective refractive index ne2 can be values ​​in between. The effective refractive index can be varied stepwise to further suppress light reflection.

[0252] Examples of materials, refractive indices, and Young's moduli in the case where the wavelength of light to be detected is 940 nm are as follows.

[0253] Pillar 62: amorphous silicon (a-Si), refractive index n1 = 3.6, Young's modulus = 80 GPa

[0254] Film 67: titanium oxide TiO2, refractive index n2 = 2.49, Young's modulus = 130 GPa

[0255] Filler 64: polymer resin, refractive index n0 = 1.4

[0256] Reflection suppression film 61: silicon nitride (Si3N4), refractive index = 1.99, Young's modulus = 290 GPa

[0257] An example of a manufacturing method will be described. The materials for the reflection-suppressing film 61, the pillars 62, and the reflection-suppressing film 63 are sequentially formed on a substrate (more specifically, for example, on the insulating layer 5). A resist pattern is formed, and the material for the reflection-suppressing film 63 is dry-etched using the resist pattern as a mask to obtain the reflection-suppressing film 63. The material for the pillars 62 is dry-etched using the reflection-suppressing film 63 as a mask to obtain the pillars 62. Furthermore, the material for the reflection-suppressing film 61 is dry-etched to obtain the reflection-suppressing film 61. At this point, a constriction C is formed at the interface between the pillars 62 and the reflection-suppressing film 61. Subsequently, the film 67 is formed. A larger amount of the film 67 is provided at the constriction C than at other portions.

[0258] Summary

[0259] For example, the technology according to the second embodiment described above is defined as follows. One of the disclosed technologies is a photodetector 100. Figures 1 to 5 、 Figures 17 to 30 As described in , the photodetector 100 includes a photoelectric conversion unit 21 and an optical layer 6 configured to cover the photoelectric conversion unit 21. The optical layer 6 includes a plurality of pillars 62 arranged side by side in the plane direction of the layer (XY plane direction) so as to guide at least the light to be detected in the incident light to the photoelectric conversion unit 21; and a film 67 (which can cover not only the side surface 62c of the pillar 62 but also the upper surface 62a), the film 67 being configured to cover at least the side surface 62c of the pillar 62. Therefore, the pillar 62 is more difficult to fall down than when the pillar 62 is not covered by the film 67. Therefore, the collapse of the pillar can be suppressed. In addition, the design rules of the pillar 62 can be relaxed. Because the difference in effective refractive index between each pillar 62 and its peripheral area can be increased, the desired optical characteristics can be easily obtained. The film 67 can also be used as a reflection suppression film.

[0260] As reference Figure 28 As described in, for example, the optical layer 6 may include a plurality of films 67 (eg, films 67-1 to 67-3) each having a different refractive index and laminated. For example, the effect of suppressing light reflection can be enhanced by using the plurality of films 67 as a multilayer reflection suppression film.

[0261] See Figure 17 、 Figure 21 、 Figure 22 、 Figures 26 to 30 As described in , the optical layer 6 may include a filler 64 that fills spaces between the plurality of pillars 62 and is provided on the film 67. The effect of suppressing the collapse of the pillars can be further enhanced.

[0262] See Figure 21 and Figure 22 As described in , etc., the film 67 may have a refractive index lower than that of the filler 64. The film 67 may have a refractive index that is the same as that of the filler 64. The film 67 may have a refractive index higher than that of the filler 64. For example, films 67 and fillers 64 having various refractive indices as described above may be used.

[0263] As reference Figures 19 to 24 As described in, for example, the plurality of pillars 62 may include pillars 62 having a circular cross-sectional shape. For example, by covering the side surface 62c of the pillar 62 having such a cross-sectional shape with a film 67, the effective refractive index difference between the pillars 62 having different diameters and their peripheral areas can be increased.

[0264] As reference Figure 23 As described in , etc., the plurality of pillars 62 may include pillars 62 having an annular cross-sectional shape that is larger than a circular cross-sectional shape. In this case, the film 67 may include a film 67-1 (first film) located outside the annular cross-sectional shape and a film 67-2 (second film) located inside the annular cross-sectional shape. The film 67-2 may have a refractive index higher than that of the pillars 62. As a result, a greater effective refractive index difference can be obtained. In addition, as described in reference Figure 24 As described in, for example, the plurality of struts 62 may include struts having a cross-sectional shape larger than a circular cross-sectional shape. Figure 25 As described in , the plurality of pillars 62 may include pillars 62 having a peripheral concave-convex cross-sectional shape.

[0265] See Figure 26 、 Figure 27 、 Figure 29 As described in , the optical layer 6 may include a reflection suppression film 63 that may be provided on the upper surface 62a of the pillar 62. This may further enhance the effect of suppressing light reflection.

[0266] See Figure 26 As described in , the film 67 may be provided to cover the side surface 62c of the reflection suppression film 63 and the side surface 63c of the upper surface 63a. In this case, the film 67 may have a refractive index higher than that of the reflection suppression film 63. The effect of the reflection suppression film 63 can be maximized.

[0267] See Figure 27 As described in

[0066] , a film 67 may be provided to cover the side surfaces 63c and the upper surface 63a of the reflection suppression film 63. The film 67 may have a refractive index lower than that of the pillars 62. The effective refractive index increases stepwise, and the effect of suppressing light reflection can be further enhanced.

[0268] As reference Figure 29 、 Figure 30 As described in , etc., the optical layer 6 may include a reflection suppression film 61 provided on the lower surface 62b of the pillar 62, a film 67 may be provided so as to also cover the side surface 61c of the reflection suppression film 61, and a constriction C may be formed at the interface between the pillar 62 and the reflection suppression film 61. The film 67 may be provided so as to fill the constriction C. Since many films 67 are provided in the constriction C, peeling of the film 67 at the interface between the pillar 62 and the reflection suppression film 61 can be suppressed.

[0269] The film 67 may have a Young's modulus greater than that of the pillar 62. By covering the pillar 62 with the film 67 having a high Young's modulus, the effect of suppressing the collapse of the pillar can be further enhanced.

[0270] The contact angle of the membrane 67 with respect to the cleaning liquid can be smaller than the contact angle of the pillars 62 with respect to the cleaning liquid. This can further suppress the collapse of the pillars.

[0271] 4. Fourth embodiment

[0272] In the fourth embodiment, the shape of the reflection-reducing film 63 is designed to suppress the collapse of the pillars.

[0273] Figure 31 and Figure 32 is a diagram illustrating an example of a schematic configuration of the optical layer 6. A reflection-reducing film 63 is provided on the upper surfaces 62a of the plurality of pillars 62. The reflection-reducing film 63 includes a plurality of first portions 631 and a plurality of second portions 632. Each of the plurality of first portions 631 is located on the upper surface 62a of a corresponding pillar 62. Each of the plurality of second portions 632 connects the first portions 631 located on the upper surface 62a of an adjacent pillar 62.

[0274] By providing the reflection-reducing film 63 on the upper surfaces 62a of the plurality of pillars 62, the fixation of each pillar 62 can be enhanced and the collapse of the pillars can be suppressed. For example, the drying process during WET treatment and the collapse of the pattern due to static electricity can be suppressed. Note that the first portion 631 of the reflection-reducing film 63 can also be referred to as a fall-prevention reinforcement beam, etc.

[0275] exist Figure 31 In the example shown, the material of the second portion 632 is the same as that of the first portion 631. The entire reflection suppression film 63 including the first portion 631 and the second portion 632 may be formed integrally. Figure 32 In the example shown, the material of the second portion 632 is different from the material of the first portion 631. For example, the design range of the strength, refractive index, etc. of the second portion 632 can be expanded.

[0276] Figures 33 to 48 2 is a diagram illustrating an embodiment of a manufacturing method.

[0277] Figures 33 to 40 An example of a manufacturing method in which the material of the second portion 632 is the same as that of the first portion 631 is shown.

[0278] like Figure 33 As shown in FIG, a pillar material 62m is provided on a reflection suppression film 61 provided on an insulating layer 5. A photoresist PR having a pattern matching the pillar shape is provided using a photolithography technique. The photoresist PR is exemplified as a multilayer resist.

[0279] like Figure 34 As shown in , the pillar material 62m is processed by dry etching or the like to obtain the pillar 62.

[0280] like Figure 35 As shown, a sacrificial layer S is formed so as to cover the reflection suppression film 61 and the pillars 62 .

[0281] like Figure 36 As shown in , the sacrificial layer S is planarized so that the sacrificial layer S has the same thickness as the height of the pillar 62 .

[0282] like Figure 37 As shown in FIG, a reflection suppression film 63 is formed to cover the sacrificial layer S and the pillars 62. The portion located on the upper surface 62a of the pillar 62 is a first portion 631. The portion located between the first portions 631 on adjacent pillars 62 is a second portion 632. A reflection suppression film 63 including the first portion 631 and the second portion 632 is obtained.

[0283] like Figure 38 As shown, fine holes 63 o are formed in a portion of the reflection suppression film 63 , for example, in a portion away from the pillars 62 .

[0284] like Figure 39 As shown, the sacrificial layer S is removed through the pores 63o. Figure 40 As shown, the reflection suppressing film 63 having the fine holes 63o is observed in a plan view (when viewed in the negative direction of the Z axis). In the figure, the pillars 62 located below the reflection suppressing film 63 are indicated by dotted lines.

[0285] After the wafer processing is completed, dicing is performed. Note that in one embodiment, another optical layer 6 can be formed thereon. In the case of obtaining such a multi-level configuration of the optical layer 6, the process of removing the sacrificial layer S can be moved to a subsequent step as needed.

[0286] Figures 41 to 48 An example of a manufacturing method is shown in the case where the material of the second portion 632 is different from the material of the first portion 631. The material of the first portion 631 is referred to as a first portion material 631m.

[0287] like Figure 41 As shown, a pillar material 62m and a first portion material 631m are sequentially provided on the reflection suppression film 61 provided on the insulating layer 5. Furthermore, a photoresist PR having a pattern matching the shape of the pillar 62 is provided.

[0288] like Figure 42 As shown in FIG, the first portion material 631m and the pillar material 62m are processed by dry etching or the like to obtain the first portion 631 and the pillar 62.

[0289] like Figure 43 As shown, a sacrificial layer S is formed so as to cover the reflection suppression film 61 , the pillar 62 , and the first portion 631 .

[0290] like Figure 44 As shown in , the sacrificial layer S is etched back so that the upper surface and side surfaces of the first portion 631 are exposed.

[0291] like Figure 45 As shown, the second portion 632 is selectively provided (eg, selectively grown) on the sacrificial layer S. A reflection suppression film 63 including the first portion 631 and the second portion 632 is obtained. Note that instead of selective growth, film formation over the entire surface and etch-back or planarization may be used in combination.

[0292] like Figure 46 As shown, fine holes 63 o are formed in a portion of the reflection suppression film 63 , for example, in a portion away from the pillars 62 .

[0293] like Figure 47 As shown in FIG, the sacrificial layer S is removed through the pores 63o. Figure 48 As shown, the reflection suppressing film 63 having fine pores 63o is observed in a plan view.

[0294] Summary

[0295] For example, the technology according to the second embodiment described above is defined as follows. One of the disclosed technologies is a photodetector 100. Figures 1 to 5 、 Figure 31 、 Figure 32 As described in [ 14 ] and [ 15 ], the photodetector 100 includes a photoelectric converter 21 and an optical layer 6 arranged to cover the photoelectric converter 21. The optical layer 6 includes a plurality of pillars 62 arranged side by side in the plane direction of the layer (the XY plane direction) to guide at least the light to be detected of the incident light toward the photoelectric converter 21; and a reflection-reducing film 63 provided on the upper surfaces 62a of the plurality of pillars 62. The reflection-reducing film 63 includes a first portion 631 located on the upper surface 62a of a corresponding pillar 62 and a second portion 632 connecting the first portion 631 located on the upper surface 62a of adjacent pillars 62. This improves the fixation of each pillar 62 and prevents pillar collapse.

[0296] As reference Figure 31 As described in , etc., the material of the second portion 632 may be the same as that of the first portion 631. In this case, for example, the reflection suppression film 63 including the first portion 631 and the second portion 632 may be integrally formed.

[0297] As reference Figure 32 As described in , etc., the material of the second portion 632 may be different from the material of the first portion 631. In this case, for example, the design range of the second portion 632 may be expanded.

[0298] 5. Conclusion

[0299] The embodiments of the present disclosure have been described above. Pillar collapse can be suppressed by the various techniques described so far. It should be noted that the effects described in this disclosure are merely examples and are not limited to the disclosed contents. Other effects may exist.

[0300] The technical scope of the present disclosure itself is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present disclosure. In addition, components of different embodiments and modifications can be appropriately combined.

[0301] It should be noted that the disclosed technology can also have the following configurations. (1)

[0303] A photodetector comprising:

[0304] a photoelectric conversion unit; and

[0305] The optical layer is provided to cover the photoelectric conversion unit, wherein

[0306] The optical layer includes:

[0307] a plurality of pillars arranged side by side in a plane direction of the layer to guide at least light to be detected among incident light to the photoelectric conversion portion; and

[0308] filler configured to fill spaces between the plurality of pillars, and

[0309] The side surface of the pillar has a curved surface that is convex toward the outside of the pillar. (2)

[0311] The photodetector according to (1), wherein

[0312] The pillars include:

[0313] an upper end portion having an upper surface of the support column;

[0314] a lower end portion having a lower surface of the support column; and

[0315] The middle portion is located between the upper end portion and the lower end portion and has a width greater than that of either the upper end portion or the lower end portion. (3)

[0317] The photodetector according to (2), wherein

[0318] The middle portion has a cross-sectional area larger than an area of ​​the upper surface or the lower surface. (4)

[0320] The photodetector according to any one of (1) to (3), wherein

[0321] The optical layer includes a film disposed to cover the upper surface of the pillar, and

[0322] When the pillar is viewed in plan view, the membrane is located inside the pillar. (5)

[0324] The photodetector according to any one of (1) to (4), wherein

[0325] The side surface of the pillar further has a curved surface that is concave toward the interior of the pillar. (6)

[0327] A photodetector comprising:

[0328] a photoelectric conversion unit; and

[0329] The optical layer is provided to cover the photoelectric conversion unit, wherein

[0330] The optical layer includes:

[0331] a plurality of pillars arranged side by side in a plane direction of the layer to guide at least light to be detected among incident light to the photoelectric conversion portion;

[0332] a reflection-reducing film provided on the lower surface of the pillar; and

[0333] a filler configured to fill spaces between the plurality of pillars and covered with a reflection suppression film, and

[0334] Reflection suppression films include:

[0335] an upper end portion, located on the lower surface of the support and having an upper surface with a reflection-reducing film;

[0336] a lower end portion having a lower surface of a reflection-reducing film; and

[0337] The middle portion is located between the upper end portion and the lower end portion and has a width smaller than that of the upper end portion. (7)

[0339] The photodetector according to (6), wherein

[0340] The side surface of the reflection suppression film has an inwardly concave curved surface. (8)

[0342] The photodetector according to (7), wherein

[0343] A recess is formed at an interface between the upper surface of the reflection suppressing film and the lower surface of the pillar, and

[0344] The depression is filled with a filler. (9)

[0346] A photodetector comprising:

[0347] a photoelectric conversion unit; and

[0348] The optical layer is provided to cover the photoelectric conversion unit, wherein

[0349] The optical layer includes:

[0350] a plurality of pillars arranged side by side in a plane direction of the layer to guide at least light to be detected among incident light to the photoelectric conversion portion; and

[0351] The membrane is provided to cover at least the side surface of the pillar. (10)

[0353] The photodetector according to (9), wherein

[0354] The membrane is arranged to cover the upper surface of the pillar. (11)

[0356] The photodetector according to (9) or (10), wherein

[0357] The optical layer includes a plurality of films each having a different refractive index, and the plurality of films are stacked. (12)

[0359] The photodetector according to any one of (9) to (11), wherein

[0360] The optical layer includes a filler configured to fill spaces between the plurality of pillars and cover the film. (13)

[0362] The photodetector according to (12), wherein

[0363] The film has a refractive index lower than that of the filler. (14)

[0365] The photodetector according to (12), wherein

[0366] The film has the same refractive index as that of the filler. (15)

[0368] The photodetector according to (12), wherein

[0369] The film has a refractive index higher than that of the filler. (16)

[0371] The photodetector according to any one of (9) to (15), wherein

[0372] The plurality of struts includes a strut having a circular cross-sectional shape. (17)

[0374] The photodetector according to (16), wherein

[0375] The plurality of struts includes a strut having an annular cross-sectional shape that is larger than a circular cross-sectional shape. (18)

[0377] The photodetector according to (17), wherein

[0378] The membrane includes:

[0379] a first membrane positioned outside the annular cross-sectional shape; and

[0380] A second membrane is located inside the annular cross-sectional shape. (19)

[0382] The photodetector according to (18), wherein

[0383] The second film has a refractive index higher than that of the pillars. (20)

[0385] The photodetector according to any one of (16) to (19), wherein

[0386] The plurality of struts includes a strut having a cross-sectional shape that is larger than a circular cross-sectional shape. (twenty one)

[0388] The photodetector according to any one of (16) to (20), wherein

[0389] The plurality of pillars include a pillar having a peripheral concave-convex cross-sectional shape. (twenty two)

[0391] The photodetector according to any one of (9) to (21), wherein

[0392] The optical layer includes a reflection-reducing film disposed on upper surfaces of the pillars. (twenty three)

[0394] The photodetector according to (22), wherein

[0395] The film is provided so as to also cover one of the side surface and the upper surface of the reflection suppression film. (twenty four)

[0397] The photodetector according to (23), wherein

[0398] The film has a refractive index higher than that of the reflection suppressing film. (25)

[0400] The photodetector according to (22), wherein

[0401] Films are also provided to cover the side surfaces and the upper surface of the reflection suppressing film. (26)

[0403] The photodetector according to (25), wherein

[0404] The film has a refractive index lower than that of the pillars. (27)

[0406] A photodetector according to any one of (9) to (26), wherein the optical layer includes a reflection suppression film arranged on the lower surface of the pillar, the film is arranged to also cover the side surface of the reflection suppression film, and a neck is formed at the interface between the pillar and the reflection suppression film. (28)

[0408] The photodetector according to (27), wherein

[0409] The membrane is arranged to fill the constriction. (29)

[0411] The photodetector according to any one of (9) to (28), wherein the membrane has a Young's modulus greater than a Young's modulus of the pillar. (30)

[0413] The photodetector according to any one of (9) to (29), wherein a contact angle of the membrane with respect to the cleaning liquid is smaller than an angle of the support with respect to the cleaning liquid. (31)

[0415] A photodetector comprising:

[0416] a photoelectric conversion unit; and

[0417] The optical layer is provided to cover the photoelectric conversion unit, wherein

[0418] The optical layer includes:

[0419] a plurality of pillars arranged side by side in a plane direction of the layer to guide at least light to be detected among incident light to the photoelectric conversion portion; and

[0420] a reflection suppression film provided on the upper surfaces of the plurality of pillars, and

[0421] Anti-reflection films include:

[0422] a first portion, each located on an upper surface of a corresponding pillar; and

[0423] The second portion connects the first portions located on the upper surfaces of adjacent pillars. (32)

[0425] The photodetector according to (31), wherein

[0426] The materials of the second part are the same as those of the first part. (33)

[0428] The photodetector according to (31), wherein

[0429] The material of the second part is different from that of the first part.

[0430] Explanation of symbols

[0431] 1 pixel array unit 2 pixels 21 photoelectric conversion unit 22 charge retention unit

[0432] 23 transistor 24 transistor 25 transistor 26 transistor 3 semiconductor substrate

[0433] 3a upper surface 3b lower surface 31 separation region 4 fixed charge film 5 insulating layer

[0434] 51 Insulating film 52 Light shielding film 53 Insulating film 6 Optical layer 61 Reflection suppression film

[0435] 61a upper surface 61b lower surface 62 support 62a upper surface 62b lower surface

[0436] 62c side surface 621 upper end 622 lower end 623 middle part

[0437] 63 Reflection suppression film 63a upper surface 63b lower surface 631 first portion

[0438] 632 Second part 64 Filler 65 Protective film 66 LTO film 67 Thin film

[0439] 7 Wiring layer 8 Insulation layer 9 Support substrate C Neck DP Concave

[0440] 100 photodetectors.

Claims

1. A photodetector comprising: Photoelectric conversion unit; as well as The optical layer is provided to cover the photoelectric conversion unit, wherein The optical layer comprises: a plurality of pillars arranged side by side in a plane direction of the layer to guide at least light to be detected among incident light to the photoelectric conversion portion; and a filler configured to fill the spaces between the plurality of pillars, and The side surface of the pillar has a curved surface that is convex toward the outside of the pillar.

2. The photodetector according to claim 1, wherein The pillars include: an upper end portion having an upper surface of the support column; a lower end portion having a lower surface of the support column; and The middle portion is located between the upper end portion and the lower end portion and has a width greater than that of either the upper end portion or the lower end portion.

3. The photodetector according to claim 2, wherein The middle portion has a cross-sectional area larger than an area of ​​the upper surface or the lower surface.

4. The photodetector according to claim 1, wherein The optical layer includes a film provided to cover upper surfaces of the pillars, and the film is located inside the pillars when the pillars are viewed in a plan view.

5. The photodetector according to claim 1, wherein The side surface of the pillar further has a curved surface that is concave toward the inside of the pillar.

6. A photodetector comprising: Photoelectric conversion unit; as well as The optical layer is provided to cover the photoelectric conversion unit, wherein The optical layer comprises: a plurality of pillars arranged side by side in a plane direction of the layer to guide at least light to be detected among incident light to the photoelectric conversion portion; a reflection-reducing film provided on the lower surface of the pillar; and a filler configured to fill spaces between the plurality of pillars and cover the reflection suppression film, and The reflection suppression film comprises: an upper end portion located on the lower surface of the pillar and having an upper surface of the reflection suppression film; a lower end portion having a lower surface of the reflection-reducing film; and The middle portion is located between the upper end portion and the lower end portion and has a width smaller than that of the upper end portion.

7. The photodetector according to claim 6, wherein The side surface of the reflection suppression film has an inwardly concave curved surface.

8. The photodetector according to claim 7, wherein A recess is formed at an interface between the upper surface of the reflection suppression film and the lower surface of the pillar, and The recess is filled with the filler.

9. A photodetector comprising: Photoelectric conversion unit; as well as The optical layer is provided to cover the photoelectric conversion unit, wherein The optical layer comprises: a plurality of pillars arranged side by side in a plane direction of the layer to guide at least light to be detected among incident light to the photoelectric conversion portion; and A film is provided to cover at least the side surface of the pillar.

10. The photodetector according to claim 9, wherein The membrane is arranged to cover the upper surface of the pillar.

11. The photodetector according to claim 9, wherein The optical layer includes a plurality of films each having a different refractive index, and the plurality of films are stacked.

12. The photodetector according to claim 9, wherein The optical layer includes a filler configured to fill spaces between the plurality of pillars and cover the film.

13. The photodetector according to claim 12, wherein The film has a refractive index lower than that of the filler.

14. The photodetector according to claim 12, wherein The film has the same refractive index as that of the filler.

15. The photodetector according to claim 12, wherein The film has a refractive index higher than that of the filler.

16. The photodetector according to claim 9, wherein The plurality of struts includes struts having a circular cross-sectional shape.

17. The photodetector according to claim 16, wherein The plurality of struts includes a strut having an annular cross-sectional shape that is larger than the circular cross-sectional shape.

18. The photodetector according to claim 17, wherein The membrane comprises: a first membrane located outside of the annular cross-sectional shape; and A second membrane is located inside the annular cross-sectional shape.

19. The photodetector according to claim 18, wherein The second film has a refractive index higher than that of the pillars.

20. The photodetector according to claim 16, wherein The plurality of struts includes a strut having a cross-sectional shape that is larger than the circular cross-sectional shape.

21. The photodetector according to claim 16, wherein The plurality of pillars include pillars having a peripheral concave-convex cross-sectional shape.

22. The photodetector according to claim 9, wherein The optical layer includes a reflection-reducing film provided on an upper surface of the pillar.

23. The photodetector according to claim 22, wherein The film is provided so as to also cover one of a side surface and an upper surface of the reflection suppression film.

24. The photodetector according to claim 23, wherein The film has a refractive index higher than that of the reflection suppressing film.

25. The photodetector according to claim 22, wherein The film is also provided to cover the side surfaces and the upper surface of the reflection suppression film.

26. The photodetector according to claim 25, wherein The film has a refractive index lower than that of the pillars.

27. The photodetector according to claim 9, wherein The optical layer includes a reflection suppression film provided on the lower surface of the pillar, The film is provided to also cover the side surface of the reflection suppression film, and A constriction is formed at an interface between the pillar and the reflection-reducing film.

28. The photodetector according to claim 27, wherein The membrane is arranged to fill the constriction.

29. The photodetector according to claim 9, wherein The membrane has a Young's modulus greater than a Young's modulus of the struts.

30. The photodetector according to claim 9, wherein A contact angle of the membrane with respect to the cleaning liquid is smaller than an angle of the pillar with respect to the cleaning liquid.

31. A photodetector comprising: Photoelectric conversion unit; as well as The optical layer is provided to cover the photoelectric conversion unit, wherein The optical layer comprises: a plurality of pillars arranged side by side in a plane direction of the layer to guide at least light to be detected among incident light to the photoelectric conversion portion; and a reflection suppression film provided on the upper surfaces of the plurality of pillars, and The reflection suppression film comprises: a first portion, each located on the upper surface of the corresponding pillar; and The second portion connects the first portions located on the upper surfaces of the adjacent pillars.

32. The photodetector according to claim 31, wherein The material of the second portion is the same as that of the first portion.

33. The photodetector of claim 31 , wherein: The material of the second portion is different from the material of the first portion.

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