Device for optical sensing and method of manufacturing the same

Abstract

Embodiments of the present invention disclose a device for optical sensing and a method for manufacturing the same. In one embodiment, the device for optical sensing includes a substrate, a photodetector, and a reflector. The photodetector is disposed in the substrate. The reflector is disposed in the substrate and is spaced apart from the photodetector, wherein the reflector has a reflective surface inclined relative to the photodetector, and the reflective surface reflects light transmitted to the reflective surface to the photodetector.

Description

Technical Field

[0001] Embodiments of the present invention relate to devices for optical sensing and methods of manufacturing the same. Background Art

[0002] Gratings are often used to enable light to be directed to a photodetector. However, gratings occupy a large area and the spacing of the gratings affects the transmission band. Summary of the invention

[0003] An embodiment of the present invention provides a device for optical sensing, comprising: a substrate; a photodetector disposed in the substrate; and a reflector disposed in the substrate and spaced apart from the photodetector, wherein the reflector has a reflective surface inclined relative to the photodetector, and the reflective surface reflects light transmitted to the reflective surface to the photodetector.

[0004] Another embodiment of the present invention provides a device for optical sensing, comprising: a substrate comprising a groove having a first side and a second side opposite to the first side; a photodetector arranged in the substrate and adjacent to the second side, wherein an arrangement direction of the first side, the second side and the photodetector is perpendicular to a thickness direction of the photodetector; and a reflector arranged on the first side of the groove and exposing a portion of the second side of the groove.

[0005] Another embodiment of the present invention provides a method for manufacturing a device for optical sensing, comprising: forming a photodetector in a substrate; forming a groove in the substrate, wherein the groove is spaced apart from the photodetector, the groove having a first side and a second side located between the first side and the photodetector, and the first side is inclined relative to the photodetector; and forming a reflector on the first side of the groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Aspects of the present invention will be best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be noted that, in accordance with standard practice in the industry, the various components are not drawn to scale. In fact, the dimensions of the various components may be arbitrarily increased or decreased for clarity of discussion.

[0007] Figure 1 A partial top view of an exemplary device for optical sensing according to some embodiments of the present invention is shown.

[0008] Figure 2 Shown along Figure 1 2 is a cross-sectional view of a device for optical sensing along line AA′ in FIG.

[0009] FIG. 3A to FIG. 3D A partial cross-sectional view showing a method for manufacturing a device for optical sensing according to some embodiments of the present invention.

[0010] Figure 4 A partial top view of another exemplary device for optical sensing according to some embodiments of the present invention is shown.

[0011] FIG. 5A to FIG. 5H A partial cross-sectional view illustrating another method for manufacturing a device for optical sensing according to some embodiments of the present invention. DETAILED DESCRIPTION

[0012] The following disclosure provides many different embodiments or examples for realizing the different features of the provided subject matter. The specific examples of components and arrangements are described below to simplify the present invention. Of course, these are only examples and are not intended to be limiting. For example, in the following description, forming a first component above or on a second component may include an embodiment in which the first component and the second component are directly contacted to form, and may also include an embodiment in which an additional component may be formed between the first component and the second component so that the first component and the second component may not be directly contacted. In addition, it will be understood that when an element is referred to as being "connected to" or "coupled to" another element, it may be directly connected to or coupled to another element, or one or more intermediate elements may be present. In addition, the present invention may repeat reference numbers and / letters in various examples. This repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or configurations discussed.

[0013] Additionally, for ease of description, spatially relative terms such as "below," "beneath," "lower," "above," "upper," etc. may be used herein to describe the relationship of one element or component to another element or component as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or during operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein should likewise be interpreted accordingly.

[0014] Figure 1 A partial top view of an exemplary device 1 for optical sensing according to some embodiments of the present invention is shown. Figure 2 Shown along Figure 1 1 is a cross-sectional view of a device 1 for optical sensing along line AA' in FIG. Figure 2 A portion of a layer or component is shown, but Figure 1 It should be noted that the device 1 for optical sensing is only an example and is not intended to limit the present invention. Therefore, it should be understood that the device 1 for optical sensing is only an example and is not intended to limit the present invention. Figure 1 and Figure 2 The device 1 for optical sensing may include providing an additional layer or element or coupling an additional layer or element to the device 1 for optical sensing. Figure 1 and Figure 2 The device 1 for optical sensing is shown in FIG. 1 , and some other layers or elements may be only briefly described herein.

[0015] refer to Figure 1 and Figure 2 According to some embodiments of the present invention, a device 1 for optical sensing includes a substrate 10 , a photodetector 11 , and a reflector 12 .

[0016] The substrate 10 may be a semiconductor substrate. In some embodiments, the material of the substrate 10 includes silicon (Si) or silicon germanium (SiGe). However, other suitable materials are within the intended scope of the present invention.

[0017] The photodetector 11 is disposed in the substrate 10. In some embodiments, the photodetector 11 is a photodiode and is formed in the substrate 10 by introducing n-type or p-type implants into the substrate 10 to form an n-type region or a p-type region. However, other suitable types of photodetectors are within the intended scope of the present invention.

[0018] In some embodiments, additional layers or elements may be provided in the substrate 10. For example, the device 1 for optical sensing may further include an isolation element 13 disposed in the substrate 10, but is not limited thereto. Figure 1 As shown, the isolation element 13 surrounds the photodetector 11 and the reflector 12. In some embodiments, the material of the isolation element 13 includes oxide, metal or air. However, other suitable materials are within the intended scope of the present invention. In some embodiments, the isolation element 13 is formed in the substrate 10 by photolithography and etching processes. However, other suitable manufacturing methods are within the intended scope of the present invention.

[0019] The reflector 12 is disposed in the substrate 10 and is spaced apart from the photodetector 11, wherein the reflector 12 has a reflective surface SR inclined relative to the photodetector 11, and the reflective surface SR reflects the light L transmitted thereto (the light L transmitted to the reflective surface SR) to the photodetector 11. In other words, the reflective surface SR is a surface of the reflector 12 that reflects the light L from the outside toward the photodetector 11. The material of the reflector 12 may include a metal, an alloy, or a combination thereof. In some embodiments, the spectral reflectivity of the reflector 12 at a wavelength less than 800 nm is greater than or equal to 0.4, and the spectral reflectivity of the reflector 12 at a wavelength greater than or equal to 800 nm is greater than or equal to 0.6. For example, the material of the reflector 12 includes aluminum (Al), aluminum copper (AlCu), silver (Ag), tungsten (W), or cobalt (Co). However, other suitable materials are within the intended scope of the present invention.

[0020] In some embodiments, the substrate 10 includes a groove T spaced apart from the photodetector 11 to provide the reflector 12. In some embodiments, the groove is V-shaped (eg, Figure 2 as shown) or U-shaped (as Figure 4 However, other shapes are within the contemplated scope of the present invention.

[0021] The trench T has a first side surface SD1 and a second side surface SD2 opposite to the first side surface SD1. In some embodiments, the photodetector 11 is adjacent to the second side surface SD2, and the second side surface SD2 is located between the first side surface SD1 and the photodetector 11. Specifically, the half side (or half side wall) of the trench T closer to the photodetector 11 is the second side surface SD2 of the trench T, and the other half side (or the other half side wall) of the trench T is the first side surface SD1 of the trench T. In this way, the arrangement direction (e.g., direction D1) of the first side surface SD1, the second side surface SD2, and the photodetector 11 is perpendicular to the thickness direction (e.g., direction D3) of the photodetector 11.

[0022] In some embodiments, the reflector 12 is disposed on the first side SD1 of the groove T, and the reflective surface SR faces the second side SD2. Since the reflector 12 exposes at least a portion of the second side SD2 of the groove T, the light L' reflected by the reflective surface SR can pass through a portion of the second side SD2 of the groove T and then be received by the photodetector 11. In other words, at least a portion of the reflector 12 is configured outside the transmission path of the light L' reflected by the reflective surface SR. Therefore, at least a portion of the light L' reflected by the reflective surface SR can be transmitted to the photodetector 11 without being blocked by the reflector 12. In some embodiments, the reflector 12 can also be disposed on a portion (e.g., the bottom) of the second side SD2 and expose another portion (e.g., the top) of the second side SD2 of the groove T. The length of the reflector 12 disposed on the second side SD2 can be controlled according to design requirements (e.g., the incident angle, incident range, or incident position of the light L' at the photodetector 11). In some optional embodiments, the reflector 12 is disposed on the first side SD1 of the groove T, but not on the second side SD2 of the groove T.

[0023] In some embodiments, the first side surface SD1 and the second side surface SD2 of the trench T both include inclined surfaces. In some embodiments, the inclination direction of the second side surface SD2 is different from the inclination direction of the first side surface SD1. In some embodiments, the inclination angle of the second side surface SD2 is different from or equal to the inclination angle of the first side surface SD1. In some embodiments, the inclination angle θ of the reflective surface SR is equal to or similar to the inclination angle of the first side surface SD1. In some embodiments, the inclination angle θ of the reflective surface SR satisfies:

[0024]

[0025] Wherein, TH is the thickness of the reflector 12 in the substrate 10, and D is the distance between the photodetector 11 and the reflector 12. For example, the thickness TH refers to the minimum depth of the reflector 12 in the substrate 10 along the direction D3, and the distance D refers to the minimum distance between the photodetector 11 and the reflector 12 along the direction D1.

[0026] In some embodiments, the reflector 12 is close to the photodetector 11. For example, the distance D between the photodetector 11 and the reflector 12 satisfies:

[0027] D≤W1

[0028] Here, W1 is the width of the photodetector along the arrangement direction of the photodetector 11 and the reflector 12 (eg, direction D1 ).

[0029] In some embodiments, the area AR of the reflective surface SR satisfies:

[0030]

[0031] Wherein, W2 is the width of the photodetector 11 along a direction D2 that is perpendicular to the thickness direction of the photodetector 11 (e.g., direction D3) and the arrangement direction of the photodetector 11 and the reflector 12 (e.g., direction D1), and W3 is the width of the photodetector 11 along the thickness direction of the photodetector 11 (e.g., direction D3).

[0032] In some embodiments, the device for optical sensing 1 further includes a first dielectric layer 14, a second dielectric layer 15, and a third dielectric layer 16. However, any number of dielectric layers in the device for optical sensing 1 is within the intended scope of the present invention.

[0033] The first dielectric layer 14 is disposed on the substrate 10 and covers the photodetector 11 and the isolation element 13. In some embodiments, the material of the first dielectric layer 14 includes oxide, silicon oxynitride, silicon nitride, or a combination of at least two thereof. In other words, the first dielectric layer 14 can be a single layer or multiple layers.

[0034] The first dielectric layer 14 includes a through hole H connected to the trench T. In some embodiments, the reflector 12 extends onto the first dielectric layer 14 along a portion of a sidewall (eg, sidewall SW1) of the through hole H. Figure 2 As shown, the reflector 12 may cover the side wall SW1 of the through hole H but not cover the side wall SW2 of the through hole H.

[0035] The second dielectric layer 15 is disposed on the reflector 12 and the first dielectric layer 14. In addition, the second dielectric layer 15 can be filled in the trench T and the through hole H. In some embodiments, the material of the second dielectric layer 15 includes oxide, silicon oxynitride, silicon nitride, or a combination of at least two of the above. In other words, the second dielectric layer 15 can be a single layer or a multilayer. In addition, the material of the second dielectric layer 15 can be the same as or different from the material of the first dielectric layer 14. In some embodiments, the material of the second dielectric layer 15 includes a light-gathering material, such as silicon oxynitride, silicon nitride, or other suitable materials, so that the light L can be focused on the reflective surface SR of the reflector 12.

[0036] The third dielectric layer 16 is disposed on the second dielectric layer 15. In some embodiments, the material of the third dielectric layer 16 includes oxide, silicon oxynitride, silicon nitride, or a combination of at least two of the above. In other words, the third dielectric layer 16 can be a single layer or a multilayer. In addition, the material of the third dielectric layer 16 can be the same as or different from the material of the first dielectric layer 14 and / or the second dielectric layer 15. In some optional embodiments, the third dielectric layer 16 can be omitted.

[0037] In the device 1 for optical sensing, although not shown, a plurality of photodetectors 11 and a plurality of reflectors 12 may be included. The plurality of photodetectors 11 and the plurality of reflectors 12 may be arranged in an array. For example, one photodetector 11 and one reflector 12 may form a sensing unit, and a plurality of sensing units formed by a plurality of photodetectors 11 and a plurality of reflectors 12 may be arranged in an array. It should be noted that any number of photodetectors 11 and any number of reflectors 12 may form a sensing unit.

[0038] Although not shown, the device 1 for optical sensing may further include other elements or layers as needed. For example, the device 1 for optical sensing may further include a collimator disposed on the third dielectric layer 16 to collimate the light L. The collimator may include a microlens array, but is not limited thereto. Any type of light collimating element is within the intended scope of the present invention. The microlens array may include a plurality of microlenses arranged corresponding to a plurality of sensing units.

[0039] In some embodiments, although not shown, the device 1 for optical sensing may further include a color filter layer disposed between the third dielectric layer 16 and the collimator. The color filter layer may include a plurality of color filter structures arranged corresponding to the plurality of sensing units.

[0040] In some embodiments, although not shown, the device 1 for optical sensing may further include multiple wiring layers for signal transmission. In some embodiments, multiple wiring layers are stacked between the third dielectric layer 16 and the color filter layer. In some optional embodiments, multiple wiring layers are stacked on the back of multiple sensing units. In this way, multiple photodetectors 11 and multiple reflectors 12 are located between multiple wiring layers and color filter layers. Additional layers or elements may be provided in the device 1 for optical sensing, and will not be repeated in the embodiments of the present invention.

[0041] In the device 1 for optical sensing, light L outside the device 1 for optical sensing can be guided to the photodetector 11 by the reflector 12; therefore, no grating is required. The reflector 12 is easy to process by a mature CMOS image sensor (CIS) process. Moreover, the reflector 12 occupies a smaller area than the grating. In addition, the reflector 12 can reflect light of various bands. Therefore, the size or volume of the device 1 for optical sensing can be reduced, and the device 1 for optical sensing can have no wavelength restrictions or a wider range of applications, such as various types of monitors, face or fingerprint recognition devices, but not limited thereto. In addition, the device 1 for optical sensing can be used with or without an optical fiber (not shown). With the help of the reflector 12, the placement angle of the optical fiber is less restricted. The placement angle of the optical fiber refers to the angle between the axis of the optical fiber and the direction D3. The placement angle of the optical fiber can be modified to improve the amount of light L' received by the photodetector 11.

[0042] FIG. 3A to FIG. 3D FIG. 1 is a partial cross-sectional view showing a method for manufacturing a device 1A for optical sensing according to some embodiments of the present invention. Figure 3A The photodetector 11 is formed in the substrate 10. The method of forming the photodetector 11 in the substrate 10 can refer to the above content, so it will not be repeated here. In some embodiments, Figure 3A As shown, the isolation element 13 is also formed in the substrate 10. The method of forming the isolation element 13 in the substrate 10 can refer to the above content, so it is not repeated here. The photodetector 11 can be formed before the isolation element 13. Optionally, the isolation element 13 can be formed before the photodetector 11.

[0043] In some embodiments, Figure 3A As shown, a first dielectric layer 14 is formed on a substrate 10. Then, a patterning process is performed on the first dielectric layer 14 and the substrate 10 to form a trench T in the substrate 10, and a through hole H is formed in the first dielectric layer 14. In the case where a large area of ​​the substrate 10 is removed by the patterning process, a V-shaped trench T is formed in the substrate 10 due to the lattice direction of the substrate 10.

[0044] The patterning process may include forming a patterned photoresist layer PR1 on the first dielectric layer 14 by a photolithography process; and removing the first dielectric layer 14 exposed by the patterned photoresist layer PR1 and the portion of the substrate 10 located below the removed first dielectric layer 14 by an etching process. In other words, in the embodiment of the V-shaped trench T, the trench T and the through hole H can be formed by one etching step. However, multiple etching steps are within the intended scope of the present invention.

[0045] refer to Figure 3B , the patterned photoresist layer PR1 is removed. In addition, a reflective layer 30 is formed to cover the trench T, the sidewalls of the through hole H (including the sidewalls SW1 and SW2) and the first dielectric layer 14. The material of the reflective layer 30 may refer to the material of the reflector 12 described above, and therefore will not be repeated here.

[0046] In addition, a dielectric layer 32 is formed to cover the reflective layer 30. The material of the dielectric layer 32 may refer to the material of the second dielectric layer 15 described above, and thus will not be repeated here.

[0047] refer to Figure 3C , patterning the dielectric layer 32 and the reflective layer 30 to form the reflector 12. The patterning process may include forming a patterned photoresist layer PR2 on the dielectric layer 32 by a photolithography process; and removing the dielectric layer 32 exposed by the patterned photoresist layer PR2 and the portion of the reflective layer 30 located under the removed dielectric layer 32 by an etching process.

[0048] refer to Figure 3D , another dielectric layer 34 is formed to cover the substrate 10 and the first dielectric layer 14 exposed by the reflector 12. The material of the other dielectric layer 34 may refer to the material of the second dielectric layer 15 described above, and thus will not be repeated here. In some embodiments, the material of the dielectric layer 32 and the other dielectric layer 34 is the same. However, the material of the dielectric layer 32 and the other dielectric layer 34 may be different.

[0049] Then, the dielectric layer 32 and the other dielectric layer 34 are thinned by a grinding process (eg, a chemical mechanical planarization process, but not limited thereto) to form a second dielectric layer 15 .

[0050] In some optional embodiments, other layers or elements (for example, Figure 2 The third dielectric layer 16 in, or the above-mentioned layer or element).

[0051] Figure 4 FIG. 2 shows a partial top view of another exemplary device 1B for optical sensing according to some embodiments of the present invention. Figure 4 , a device 1B for optical sensing and Figure 2 The main difference between the device for optical sensing 1 in FIG. 1 and FIG. 2 is that the trench TB in the substrate 10 is U-shaped. The first side SD1 and the second side SD2 of the U-shaped trench TB each include a curved surface inclined relative to the photodetector 11. The inclination angle θ of the reflective surface SR is an acute angle between the direction D1 and a line from the highest point to the lowest point of the reflector 12 on the first side SD1.

[0052] FIG. 5A to FIG. 5H FIG. 1 is a partial cross-sectional view of another method for manufacturing a device 1C for optical sensing according to some embodiments of the present invention. Specifically, FIG. 5A to FIG. 5H A method for manufacturing a U-shaped trench TB is shown. For simplicity, Figure 5H The device 1C for optical sensing is not shown. Figure 4 The photodetector 11 and the isolation element 13 in FIG. However, it should be understood that Figure 5H The device for optical sensing 1C provides an additional layer or element or couples the additional layer or element to Figure 5H The device 1C for optical sensing is shown in FIG. 1 , and some other layers or elements may be only briefly described here.

[0053] refer to Figure 5A and Figure 5B, a patterning process is performed on the first dielectric layer 14 to form an opening O1 on the first dielectric layer 14. The patterning process may include forming a patterned photoresist layer PR3 on the first dielectric layer 14 by a photolithography process; and removing a portion of the first dielectric layer 14 exposed by the patterned photoresist layer PR3 by an etching process.

[0054] refer to Figure 5C and Figure 5D , the patterned photoresist layer PR3 is trimmed to expose a larger area of ​​the first dielectric layer 14. Then, another etching process is performed to form another opening O2 on the first dielectric layer 14. The opening O2 is wider and deeper than the opening O1. In addition, the opening O2 is, for example, a T-shaped opening with a wide top and a narrow bottom.

[0055] refer to Figure 5E , then repeat Figure 5C and Figure 5D The step of forming the opening O3 extending from the top of the first dielectric layer 14 to the substrate 10 is performed. The opening O3 is wider and deeper than the opening O2. In addition, the opening O3 is, for example, a stepped opening having a wide top and a narrow bottom. Then, the patterned photoresist layer PR3 is removed.

[0056] refer to Fig. 5F , a rounding etching process is performed to form a U-shaped trench TB in the substrate 10 and a through hole H in the first dielectric layer 14. In other words, in the embodiment of the U-shaped trench TB, the trench TB and the through hole H are formed by multiple etching steps.

[0057] refer to Figure 5G and Figure 5H , then execute FIG. 3B to FIG. 3D The steps described in the above are performed to form the reflector 12 and the second dielectric layer 15. Specifically, a reflective layer 30 is formed to cover the trench TB, the sidewalls (including the sidewalls SW1 and SW2) of the through hole H and the first dielectric layer 14. The material of the reflective layer 30 may refer to the material of the reflector 12 described above, so it will not be repeated here.

[0058] After forming the reflective layer 30, a dielectric layer 32 covering the reflective layer 30 is formed. The material of the dielectric layer 32 may refer to the material of the second dielectric layer 15 described above, so it is not repeated here. Then, the dielectric layer 32 and the reflective layer 30 are patterned to form the reflector 12. The patterning process may include forming a patterned photoresist layer (not shown) on the dielectric layer 32 by a photolithography process; and removing the dielectric layer 32 exposed by the patterned photoresist layer and the portion of the reflective layer 30 located under the removed dielectric layer 32 by an etching process.

[0059] After the reflector 12 is formed, another dielectric layer 34 is formed to cover the substrate 10 and the first dielectric layer 14 exposed by the reflector 12. The material of the other dielectric layer 34 may refer to the material of the second dielectric layer 15 described above, so it is not repeated here. In some embodiments, the material of the dielectric layer 32 and the other dielectric layer 34 is the same. However, the material of the dielectric layer 32 and the other dielectric layer 34 may be different.

[0060] Then, the dielectric layer 32 and the other dielectric layer 34 are thinned by a grinding process (eg, a chemical mechanical planarization process, but not limited thereto) to form a second dielectric layer 15 .

[0061] In some optional embodiments, other layers or elements (for example, Figure 2 The third dielectric layer 16 in, or the above-mentioned layer or element).

[0062] Based on the above discussion, it can be seen that the present invention provides various advantages. However, it should be understood that not all advantages need to be discussed herein, and other embodiments may provide different advantages, and no specific advantage is required by all embodiments.

[0063] According to some embodiments of the present invention, a device for optical sensing includes a substrate, a photodetector, and a reflector. The photodetector is disposed in the substrate. The reflector is disposed in the substrate and is spaced apart from the photodetector, wherein the reflector has a reflective surface inclined relative to the photodetector, and the reflective surface reflects light transmitted to the reflective surface to the photodetector.

[0064] In the above-mentioned device for optical sensing, wherein the substrate is a semiconductor substrate, the photodetector is a photodiode, and the device for optical sensing further includes an isolation element, which is arranged in the substrate and surrounds the photodetector and the reflector.

[0065] In the above-mentioned device for optical sensing, wherein the substrate includes a groove spaced apart from the photodetector, the groove having a first side and a second side located between the first side and the photodetector, the reflector is arranged on the first side, and the reflective surface faces the second side.

[0066] In the above-mentioned device for optical sensing, wherein the substrate includes a groove spaced apart from the photodetector, the groove having a first side and a second side located between the first side and the photodetector, the reflector is arranged on the first side, and the reflective surface faces the second side, and the groove is V-shaped or U-shaped.

[0067] In the above-mentioned device for optical sensing, wherein the substrate includes a groove spaced apart from the photodetector, the groove having a first side and a second side located between the first side and the photodetector, the reflector is arranged on the first side, and the reflective surface faces the second side, and also includes: a first dielectric layer, which is arranged on the substrate and includes a through hole connected to the groove, wherein the reflector extends onto the first dielectric layer along a portion of the side wall of the through hole; and a second dielectric layer, which is arranged on the reflector and the first dielectric layer.

[0068] In the above device for optical sensing, the spectral reflectivity of the reflector at a wavelength less than 800 nm is greater than or equal to 0.4, and the spectral reflectivity of the reflector at a wavelength greater than or equal to 800 nm is greater than or equal to 0.6.

[0069] In the above-mentioned device for optical sensing, the inclination angle θ of the reflective surface satisfies:

[0070]

[0071] Wherein, TH is the thickness of the reflector in the substrate, and D is the distance between the photodetector and the reflector.

[0072] In the above-mentioned device for optical sensing, the distance D between the photodetector and the reflector satisfies:

[0073] D≤W1

[0074] Wherein, W1 is the width of the photodetector along the arrangement direction of the photodetector and the reflector.

[0075] In the above-mentioned device for optical sensing, the area AR of the reflective surface satisfies:

[0076]

[0077] Among them, W2 is the width of the photodetector along a direction perpendicular to the thickness direction of the photodetector and the arrangement direction of the photodetector and the reflector, and W3 is the width of the photodetector along the thickness direction of the photodetector.

[0078] According to some embodiments of the present invention, a device for optical sensing includes a substrate, a photodetector, and a reflector. The substrate includes a groove having a first side and a second side opposite to the first side. The photodetector is arranged in the substrate and adjacent to the second side, wherein the arrangement direction of the first side, the second side, and the photodetector is perpendicular to the thickness direction of the photodetector. The reflector is arranged on the first side of the groove and exposes a portion of the second side of the groove.

[0079] In the above device for optical sensing, the spectral reflectivity of the reflector at a wavelength less than 800 nm is greater than or equal to 0.4, and the spectral reflectivity of the reflector at a wavelength equal to or greater than 800 nm is greater than or equal to 0.6.

[0080] In the above device for optical sensing, wherein the groove is V-shaped or U-shaped, and the inclination angle θ of the reflective surface satisfies:

[0081]

[0082] Wherein, TH is the thickness of the reflector in the substrate, and D is the distance between the photodetector and the reflector.

[0083] According to some embodiments of the present invention, a method for manufacturing a device for optical sensing includes the following steps: forming a photodetector in a substrate; forming a groove in the substrate, wherein the groove is spaced apart from the photodetector, the groove having a first side and a second side between the first side and the photodetector, and the first side is inclined relative to the photodetector; and forming a reflector on the first side of the groove.

[0084] In the above method for manufacturing the device for optical sensing, the inclination direction of the second side surface is different from the inclination direction of the first side surface.

[0085] In the above-mentioned method for manufacturing a device for optical sensing, wherein the substrate is a semiconductor substrate, the photodetector is a photodiode, and the method for manufacturing the device for optical sensing further comprises: before forming the trench, forming an isolation element in the substrate.

[0086] The manufacturing method of the above-mentioned device for optical sensing also includes: before forming the groove, forming a first dielectric layer on the substrate; before forming the reflector, forming a through hole connected to the groove in the first dielectric layer; and forming a second dielectric layer on the reflector and the first dielectric layer.

[0087] In the above-mentioned manufacturing method of the device for optical sensing, it also includes: before forming the groove, forming a first dielectric layer on the substrate; before forming the reflector, forming a through hole connected to the groove in the first dielectric layer; and forming a second dielectric layer on the reflector and the first dielectric layer, wherein forming the reflector and the second dielectric layer includes: forming a reflective layer, the reflective layer covers the groove, the sidewall of the through hole and the first dielectric layer; forming a dielectric layer covering the reflective layer; patterning the dielectric layer and the reflective layer to form the reflector; forming another dielectric layer, the other dielectric layer covers the substrate and the first dielectric layer exposed by the reflector; and thinning the dielectric layer and the other dielectric layer to form the second dielectric layer.

[0088] In the above-mentioned manufacturing method of the device for optical sensing, it also includes: before forming the groove, forming a first dielectric layer on the substrate; before forming the reflector, forming a through hole connected to the groove in the first dielectric layer; and forming a second dielectric layer on the reflector and the first dielectric layer, wherein forming the reflector and the second dielectric layer includes: forming a reflective layer, the reflective layer covers the groove, the sidewall of the through hole and the first dielectric layer; forming a dielectric layer covering the reflective layer; patterning the dielectric layer and the reflective layer to form the reflector; forming another dielectric layer, the other dielectric layer covers the substrate and the first dielectric layer exposed by the reflector; and thinning the dielectric layer and the other dielectric layer to form the second dielectric layer, wherein the dielectric layer and the other dielectric layer are made of the same material.

[0089] In the above-mentioned manufacturing method of the device for optical sensing, it also includes: before forming the groove, forming a first dielectric layer on the substrate; before forming the reflector, forming a through hole connected to the groove in the first dielectric layer; and forming a second dielectric layer on the reflector and the first dielectric layer, wherein the groove is a V-shaped groove, and the groove and the through hole are formed by one etching step.

[0090] In the above-mentioned manufacturing method of the device for optical sensing, it also includes: before forming the groove, forming a first dielectric layer on the substrate; before forming the reflector, forming a through hole connected to the groove in the first dielectric layer; and forming a second dielectric layer on the reflector and the first dielectric layer, wherein the groove is a U-shaped groove, and the groove and the through hole are formed by multiple etching steps.

[0091] The features of several embodiments are summarized above so that those skilled in the art can better understand aspects of the present invention. Those skilled in the art should understand that they can easily use the present invention as a basis to design or modify other processes and structures for implementing the same purpose and / or achieving the same advantages as the embodiments introduced herein. Those skilled in the art should also appreciate that this equivalent configuration does not deviate from the spirit and scope of the present invention, and that they can make multiple changes, substitutions and changes herein without departing from the spirit and scope of the present invention.

Claims

1. A device for optical sensing, comprising: substrate; a photodetector disposed in the substrate, wherein the substrate includes a trench spaced apart from the photodetector; and a reflector disposed in the substrate and spaced apart from the photodetector, wherein the reflector has a reflective surface inclined relative to the photodetector, and the reflective surface reflects light transmitted onto the reflective surface toward the photodetector; A first dielectric layer is disposed on the substrate and includes a through hole connected to the trench, wherein the reflector extends onto the first dielectric layer along a portion of a sidewall of the through hole.

2. The device for optical sensing according to claim 1, wherein: The substrate is a semiconductor substrate, The photodetector is a photodiode, and The device for optical sensing also includes an isolation element disposed in the substrate and surrounding the photodetector and the reflector.

3. The device for optical sensing according to claim 1, wherein: The trench has a first side and a second side between the first side and the photodetector, The reflector is disposed on the first side, and The reflective surface faces the second side surface.

4. The device for optical sensing according to claim 3, wherein: The groove is V-shaped or U-shaped.

5. The device for optical sensing according to claim 3, further comprising: The second dielectric layer is disposed on the reflector and the first dielectric layer.

6. The device for optical sensing according to claim 1, wherein: The spectral reflectivity of the reflector at a wavelength less than 800 nm is greater than or equal to 0.4, and the spectral reflectivity of the reflector at a wavelength greater than or equal to 800 nm is greater than or equal to 0.

6.

7. The device for optical sensing according to claim 1, wherein: The inclination angle θ of the reflecting surface satisfies: Wherein, TH is the thickness of the reflector in the substrate, and D is the distance between the photodetector and the reflector.

8. The device for optical sensing according to claim 1, wherein: The distance D between the photodetector and the reflector satisfies: D≤W1 Wherein, W1 is the width of the photodetector along the arrangement direction of the photodetector and the reflector.

9. The device for optical sensing according to claim 1, wherein: The area AR of the reflecting surface satisfies: Among them, W2 is the width of the photodetector along a direction perpendicular to the thickness direction of the photodetector and the arrangement direction of the photodetector and the reflector, and W3 is the width of the photodetector along the thickness direction of the photodetector.

10. A device for optical sensing, comprising: a substrate comprising a trench having a first side and a second side opposite to the first side; a photodetector disposed in the substrate and adjacent to the second side surface, wherein an arrangement direction of the first side surface, the second side surface, and the photodetector is perpendicular to a thickness direction of the photodetector; and a reflector disposed on the first side of the groove and exposing a portion of the second side of the groove; A first dielectric layer is disposed on the substrate and includes a through hole connected to the trench, wherein the reflector extends onto the first dielectric layer along a portion of a sidewall of the through hole.

11. The device for optical sensing according to claim 10, wherein: The spectral reflectivity of the reflector at a wavelength less than 800 nm is greater than or equal to 0.4, and the spectral reflectivity of the reflector at a wavelength equal to or greater than 800 nm is greater than or equal to 0.

6.

12. The device for optical sensing according to claim 10, wherein: The groove is V-shaped or U-shaped, and the inclination angle θ of the reflective surface satisfies: Wherein, TH is the thickness of the reflector in the substrate, and D is the distance between the photodetector and the reflector.

13. A method for manufacturing a device for optical sensing, comprising: forming a photodetector in a substrate; forming a trench in the substrate, wherein the trench is spaced apart from the photodetector, the trench has a first side and a second side between the first side and the photodetector, and the first side is inclined relative to the photodetector; and forming a reflector on the first side of the groove; Before forming the trench, forming a first dielectric layer on the substrate; Before forming the reflector, a through hole connected to the trench is formed in the first dielectric layer, wherein the reflector extends onto the first dielectric layer along a portion of a sidewall of the through hole.

14. The method for manufacturing a device for optical sensing according to claim 13, wherein: An inclination direction of the second side surface is different from an inclination direction of the first side surface.

15. The method for manufacturing a device for optical sensing according to claim 13, wherein: The substrate is a semiconductor substrate, The photodetector is a photodiode, and The method for manufacturing the device for optical sensing further includes: forming an isolation element in the substrate before forming the trench.

16. The method for manufacturing a device for optical sensing according to claim 13, further comprising: A second dielectric layer is formed on the reflector and the first dielectric layer.

17. The method for manufacturing a device for optical sensing according to claim 16, wherein: Forming the reflector and the second dielectric layer includes: forming a reflective layer, wherein the reflective layer covers the groove, the sidewall of the through hole and the first dielectric layer; forming a dielectric layer covering the reflective layer; patterning the dielectric layer and the reflective layer to form the reflector; forming another dielectric layer covering the substrate and the first dielectric layer exposed by the reflector; and The dielectric layer and the another dielectric layer are thinned to form the second dielectric layer.

18. The method for manufacturing a device for optical sensing according to claim 17, wherein: The dielectric layer is made of the same material as the another dielectric layer.

19. The method for manufacturing a device for optical sensing according to claim 13, wherein: The groove is a V-shaped groove, and the groove and the through hole are formed by one etching step.

20. The method for manufacturing a device for optical sensing according to claim 13, wherein: The groove is a U-shaped groove, and the groove and the through hole are formed by a plurality of etching steps.

Images