Optical structure

Abstract

An optical structure is provided. The optical structure includes a sensor, a bandpass filter, and a plurality of protrusions. The bandpass filter is disposed above the sensor. The protrusions are disposed on the bandpass filter. The bandpass filter allows light having a wavelength between 700 nm and 3000 nm to pass through. The protrusions have a size distribution that controls the phase of incident light to be between 0 and 2π.

Description

TECHNICAL FIELD

[0001] The present application relates to an optical structure, and more particularly to an optical structure with planar lenses. BACKGROUND

[0002] Current infrared camera devices include a near-infrared (NIR) complementary metal-oxide-semiconductor (CMOS) image sensor, a bandpass filter, and a plastic lens set. The bandpass filter is disposed above the near-infrared CMOS image sensor. The plastic lens set includes a plurality of lenses vertically stacked on the bandpass filter. Due to the vertically stacked plastic lens set, the infrared camera device has a vertical height greater than 3.5 mm, which is not conducive to the miniaturization of semiconductor components.

[0003] Therefore, it is desirable to develop an optical structure with a low vertical height while maintaining proper optical effects. SUMMARY

[0004] According to an embodiment of the present application, an optical structure is provided. The optical structure includes a sensor, a first bandpass filter, and a plurality of protrusions. The first bandpass filter is disposed above the sensor. The protrusions are disposed on the first bandpass filter.

[0005] In some embodiments, the sensor includes a complementary metal-oxide-semiconductor (CMOS) image sensor or a fingerprint sensor.

[0006] In some embodiments, the first bandpass filter allows light having a wavelength between 700 nm and 3000 nm to pass through.

[0007] In some embodiments, the protrusions include cylinders, hexagonal cylinders, or square cylinders. In some embodiments, at least one protrusion includes a first portion and a space, the space being surrounded by the first portion. In some embodiments, the at least one protrusion further includes a second portion, the second portion being surrounded by the space. In some embodiments, the protrusions are cylinders, and each protrusion has a diameter between 150 nm and 300 nm. In some embodiments, the protrusions include a high refractive index material having a refractive index between 3.0 and 5.0. In some embodiments, the protrusions include titanium oxide (TiO2), silicon nitride (SiN), silicon oxide (SiO2), silicon hydride (SiH), or a combination thereof. In some embodiments, the protrusions have a pitch between 100 nm and 1000 nm. In some embodiments, the protrusions have a size distribution that controls the phase of incident light to be between 0 and 2π.

[0008] In some embodiments, the optical structure further comprises a glass substrate having a thickness between 50 microns and 500 microns, disposed between the sensor and the first bandpass filter, wherein the first bandpass filter is disposed on a top side of the glass substrate. In some embodiments, the optical structure further comprises a second bandpass filter disposed on a bottom side of the glass substrate.

[0009] In some embodiments, the optical structure further comprises a space between the sensor and the glass substrate. In some embodiments, the optical structure further comprises a low-refractive-index material, a normal-refractive-index material, or a combination thereof, filling the space.

[0010] In some embodiments, the optical structure further comprises a low-refractive-index material layer disposed between the sensor and the first bandpass filter. In some embodiments, the optical structure further comprises a polymer layer disposed between the low-refractive-index material layer and the first bandpass filter. In some embodiments, the optical structure further comprises a plurality of second protrusions disposed in the polymer layer.

[0011] In some embodiments, the optical structure further comprises a second polymer layer covering the first bandpass filter and the protrusions. In some embodiments, the optical structure further comprises an anti-reflective layer disposed on the second polymer layer.

[0012] In some embodiments, the sensor is connected to a printed circuit board by wire bonding. In some embodiments, the sensor is connected to a printed circuit board by solder balls.

[0013] This invention replaces traditional vertically stacked modular lenses with planar lenses (e.g., metalenses or Fresnellenses). When the planar lens and bandpass filter are integrated onto a glass substrate of appropriate thickness and packaged in a chip-on-board (COB) manner, the overall package height can be reduced to less than approximately 2 cm. When the planar lens and bandpass filter are integrated onto a glass substrate of appropriate thickness and packaged in a chip-scale package (CSP), the overall package height can be reduced to less than approximately 1.2 cm, and the package size along the XY direction can also be miniaturized. When the planar lens and bandpass filter are stacked on a chip using a wafer fabrication process and packaged in a chip-on-board (COB) manner, the overall package height can be reduced to less than approximately 1 cm. The optimized size distribution of the planar lens controls the phase of the incident light to be between 0 and 2π, thereby achieving optical maneuverability and controlling wave behavior. Furthermore, the planar lens has a transmittance of over 80%, eliminating the effects of reflection and refraction. Plane lenses have a focusing function, which is sufficient to show that they can replace traditional vertically stacked modular lenses. Furthermore, solid or hollow plane lenses can handle situations where the light passing through the plane lens may contain single or multiple wavelengths, effectively reducing dispersion (aberration).

[0014] The following embodiments are implemented with reference to the accompanying drawings. Attached Figure Description

[0015] A more complete understanding of the invention can be obtained by reading the following embodiments and examples and referring to the accompanying drawings, wherein:

[0016] Figure 1 This is a cross-sectional schematic diagram of an optical structure according to an embodiment of the present invention;

[0017] Figure 2 This is a cross-sectional schematic diagram of an optical structure according to an embodiment of the present invention;

[0018] Figure 3 This is a cross-sectional schematic diagram of an optical structure according to an embodiment of the present invention;

[0019] Figure 4 This is a cross-sectional schematic diagram of an optical structure according to an embodiment of the present invention;

[0020] Figure 5 This is a top view of a protrusion of an optical structure according to an embodiment of the present invention;

[0021] Figure 6 This is a top view of a protrusion of an optical structure according to an embodiment of the present invention;

[0022] Figure 7 is a top view of a protrusion of an optical structure according to an embodiment of the present application;

[0023] Figure 8 is a graph showing the penetration of a protrusion and the relationship between the size of the protrusion and the phase of incident light according to an embodiment of the present application;

[0024] Figures 9A-9N is a cross-sectional view of a method of manufacturing an optical structure according to an embodiment of the present application;

[0025] Figures 10A-10D is a cross-sectional view of a method of manufacturing an optical structure according to an embodiment of the present application; and

[0026] Figures 11A-11L is a cross-sectional view of a method of manufacturing an optical structure according to an embodiment of the present application.

[0027] In the drawings:

[0028] 10: optical structure

[0029] 12: sensor

[0030] 14: (first) band pass filter

[0031] 16: protrusion

[0032] 16': material layer

[0033] 18: substrate

[0034] 20: photoelectric conversion unit

[0035] 22: color filter

[0036] 24: microlens

[0037] 26: glass substrate

[0038] 26a: top side of glass substrate

[0039] 26b: bottom side of glass substrate

[0040] 28: second band pass filter

[0041] 30: space

[0042] 32, 44: polymer layer

[0043] 34: anti-reflection layer

[0044] 36: printed circuit board

[0045] 38: wire bonding

[0046] 39, 41, 45: encapsulation material

[0047] 40: tin ball

[0048] 42: low refractive index material layer

[0049] 46: second protrusion

[0050] 48: solid cylinder

[0051] 50: solid hexagonal cylinder

[0052] 52: solid square cylinder

[0053] 54: hollow cylinder

[0054] 54a: first portion of hollow cylinder

[0055] 54b: space of hollow cylinder

[0056] 56: hollow hexagonal cylinder

[0057] 56a: first portion of hollow hexagonal cylinder

[0058] 56b: space of hollow hexagonal cylinder

[0059] 58: hollow square cylinder

[0060] 58a: first portion of hollow square cylinder

[0061] 58b: space of hollow square cylinder

[0062] 60: hollow cylinder

[0063] 60a: first portion of hollow cylinder

[0064] 60b: space of hollow cylinder

[0065] 60c: second portion of hollow cylinder

[0066] 62: hollow hexagonal cylinder

[0067] 62a: first portion of hollow hexagonal cylinder

[0068] 62b: space of hollow hexagonal cylinder

[0069] 62c: second portion of hollow hexagonal cylinder

[0070] 64: hollow square cylinder

[0071] 64a: first portion of hollow square cylinder

[0072] 64b: space of hollow square cylinder

[0073] 64c: second portion of the hollow square column

[0074] 66: photoresist layer

[0075] 66': patterned photoresist layer

[0076] 68: radiation source

[0077] 70: photomask

[0078] C: center of the protrusion

[0079] D: diameter of the protrusion

[0080] H: height of the chip-on-board (COB) / chip-scale package (CSP) of the optical structure

[0081] LS: light source

[0082] P: pitch of two centers of adjacent protrusions

[0083] T: thickness of the glass substrate DETAILED DESCRIPTION

[0084] The optical structure of the present disclosure is described in detail in the following description. In the following embodiments, for the purpose of explanation, numerous specific details and examples are set forth in order to provide a thorough understanding of the present disclosure. The specific elements and configurations described in the following embodiments are presented for the purpose of clarity and explanation. However, it will be apparent to one skilled in the art that the example embodiments set forth herein are presented for illustrative purposes only, and that the inventive concept can be embodied in various forms, not limited to those example embodiments. In addition, drawings of different embodiments can use similar and / or corresponding numbers to represent similar and / or corresponding elements in order to clearly describe the present disclosure. However, the use of similar and / or corresponding numbers in drawings of different embodiments does not imply any correlation between the different embodiments. In addition, in the present specification, expressions such as "a first material layer disposed on / over a second material layer" can refer to direct contact of the first material layer and the second material layer, or it can refer to a non-contact state with one or more intermediate layers between the first material layer and the second material layer. In the above case, the first material layer can not be in direct contact with the second material layer.

[0085] In addition, in the present specification, relative expressions are used. For example, "lower", "bottom", "higher", or "top" are used to describe the position of one element with respect to another element. It should be understood that if the device is upside down, the "lower" element will become the "higher" element.

[0086] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be apparent to those skilled in the art that various modifications and variations can be made to the present application without departing from the spirit or scope of the application. Thus, it is intended that the present application cover modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.

[0087] In the description, relative terms such as "lower," "upper," "horizontal," "vertical," "below," "above," "top," "bottom," and the like are used as a shorthand for describing the orientation of elements in the drawings. The relative terms are intended to encompass different orientations of the device in its operation, for example, in its use or during manufacture, in addition to the orientation depicted in the drawings. The terms "connected" and "coupled" are used broadly and encompass both direct and indirect connections and couplings, as well as permanent and non-permanent connections and couplings, and are used in their broadest sense to encompass any connection or coupling between two elements, whether direct or indirect, permanent or non-permanent, and whether mechanical, electrical, or otherwise.

[0088] It is to be understood that the terms so far as the terms first, second, third, etc. can be used in this document to describe various elements, components, regions, layers, parts and / or sections. These elements, components, regions, layers, parts and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, part or section from another element, component, region, layer, part or section. Therefore, a first element, component, region, layer, part or section discussed below can be called a second element, component, region, layer, part or section without departing from the teachings of the present disclosure.

[0089] In the description, the terms "about," "approximately," "substantially" generally mean within 20% or within 10% or within 5% or within 3% or within 2% or within 1% or within 0.5% of a given value or range of values. A value or range of values that is about a given value or range of values also implies that the "about" or "approximately" or "substantially" meaning is implied even if not specifically stated.

[0090] The following description is presented to enable any person skilled in the art to make and use the application. Various modifications to the embodiments described will be readily apparent to those skilled in the art, and the generic principles described herein can be applied to other embodiments and applications without the use of the inventive faculty. Therefore, the present application is not intended to be limited to the embodiments described herein but is to be accorded the widest scope consistent with the principles and features described herein.

[0091] Referring to Figure 1 , according to an embodiment of the present application, an optical structure 10 is provided. Figure 1 is a cross-sectional view of the optical structure 10.

[0092] In some embodiments, the optical structure 10 includes a sensor 12, a first bandpass filter 14, and a plurality of protrusions 16. The first bandpass filter 14 is disposed above the sensor 12. The protrusions 16 are disposed on the first bandpass filter 14. Figure 1 The sensor 12 includes a substrate 18, a plurality of photoelectric conversion units 20, a plurality of color filters 22, and a plurality of microlenses 24. The photoelectric conversion units 20 are disposed in the substrate 18. The color filters 22 are disposed on the substrate 18 and correspond to the photoelectric conversion units 20, respectively. The microlenses 24 are disposed on the color filters 22 and correspond to the photoelectric conversion units 20, respectively.

[0093] In some embodiments, the substrate 18 can include a bulk semiconductor substrate, such as a semiconductor wafer. For example, the substrate 18 can include a silicon wafer. The substrate 18 can include silicon or other elemental semiconductor materials, such as germanium. In some embodiments, the substrate 18 can include a compound semiconductor. The compound semiconductor can include gallium arsenide, silicon carbide, indium arsenide, indium phosphide, other suitable materials, or combinations of the foregoing. In some embodiments, the substrate 18 can include a semiconductor-on-insulator (SOI) substrate. The semiconductor-on-insulator substrate can be fabricated using a separation by implantation of oxygen (SIMOX) process, a wafer bonding process, other applicable methods, or combinations of the foregoing. In some embodiments, the substrate 18 can include an undoped substrate.

[0094] In some embodiments, the photoelectric conversion units 20 can include elements that convert light into electrical energy, such as photodiodes (PDs). In some embodiments, the color filters 22 can include organic color filters or inorganic color filters. In some embodiments, the color filters 22 can include red color filters, green color filters, blue color filters, or combinations of the foregoing.

[0095] In some embodiments, the sensor 12 includes a complementary metal-oxide-semiconductor (CMOS) image sensor. In some embodiments, the sensor 12 can include other suitable sensors, such as a fingerprint sensor.

[0096] Figure 1 In some embodiments, the optical structure 10 includes a sensor 12, a first bandpass filter 14, and a plurality of protrusions 16. The first bandpass filter 14 is disposed above the sensor 12. The protrusions 16 are disposed on the first bandpass filter 14.

[0097] ​In some embodiments, the first bandpass filter 14 may comprise a single layer or multiple layers. In some embodiments, the material of the first bandpass filter 14 may include silicide (SiH), silicon germanide (SiGe), silicide germanide (GeH), or a combination thereof. In some embodiments, the first bandpass filter 14 (i.e., a near-infrared bandpass filter) may allow light with wavelengths between approximately 700 nanometers and approximately 3000 nanometers to pass through. For example, the first bandpass filter 14 may allow light of a single wavelength to pass through, such as light with wavelengths of approximately 850 nanometers, approximately 940 nanometers, approximately 1350 nanometers, or approximately 1550 nanometers; or, the first bandpass filter 14 may allow light of multiple wavelengths to pass through, such as light with wavelengths of approximately 850 ± 5 nanometers, approximately 940 ± 5 nanometers, approximately 1350 ± 5 nanometers, approximately 1550 ± 5 nanometers, or a combination thereof.

[0098] In some embodiments, the protrusion 16 may comprise a high refractive index material having a refractive index between about 3.0 and about 5.0. In some embodiments, the material of the protrusion 16 may include titanium oxide (TiO2), silicon nitride (SiN), silicon oxide (SiO2), hydrogen silicide (SiH), or combinations thereof. The structure, shape, size, and configuration of the protrusion 16 will be described in detail below (e.g.). Figures 5-8 ).

[0099] exist Figure 1 In this optical structure 10, a glass substrate 26 is also included. The glass substrate 26 is disposed between the sensor 12 and the first bandpass filter 14. In some embodiments, the thickness T of the glass substrate 26 is between approximately 50 micrometers and approximately 500 micrometers. The first bandpass filter 14 is disposed on the top side 26a of the glass substrate 26. The optical structure 10 also includes a second bandpass filter 28. The second bandpass filter 28 is disposed on the bottom side 26b of the glass substrate 26. In some embodiments, the second bandpass filter 28 is similar to the first bandpass filter 14. That is, the second bandpass filter 28 (i.e., a near-infrared bandpass filter) allows light with wavelengths between approximately 700 nanometers and approximately 3000 nanometers to pass through. For example, the second bandpass filter 28 may allow single-wavelength light to pass through, such as light with wavelengths of approximately 850 nm, approximately 940 nm, approximately 1350 nm, or approximately 1550 nm; or, the second bandpass filter 28 may allow multiple wavelengths of light to pass through, such as light with wavelengths of approximately 850 ± 5 nm, approximately 940 ± 5 nm, approximately 1350 ± 5 nm, approximately 1550 ± 5 nm, or a combination thereof. In some embodiments, the first bandpass filter 14 or the second bandpass filter 28 may be omitted. In some embodiments, the protrusion 16 may be selectively disposed on the bottom side 26b of the glass substrate 26. For example, the protrusion 16 may be disposed on the second bandpass filter 28, facing the sensor 12.

[0100] In Figure 1 some embodiments, the optical structure 10 further includes a space 30 between the sensor 12 and the glass substrate 26. In some embodiments, the optical structure 10 can further include a low refractive index material (n < 1.45), a normal-refractive-index material (n > 1.5), or a combination thereof, filling the space 30.

[0101] In Figure 1 some embodiments, the optical structure 10 further includes a polymer layer 32 covering and protecting the first band-pass filter 14 and the protrusions 16 thereunder. In some embodiments, the polymer layer 32 can include a polymer material having a high transmittance with a refractive index between about 1.2 and about 2.0. The optical structure 10 further includes an anti-reflective layer 34 disposed on the polymer layer 32.

[0102] In Figure 1 some embodiments, the sensor 12 is connected to a printed circuit board (PCB) 36 by wire bonding 38. That is, the optical structure 10 is packaged in a Chip On Board (COB) manner. A packaging material 39 covers a portion of the substrate 18 and the printed circuit board (PCB) 36, and surrounds the glass substrate 26 and the elements formed on the glass substrate 26, leaving the space 30. In some embodiments, the height H of the Chip On Board (COB) of the optical structure 10 is less than about 2 cm. In addition, a light source LS is disposed above the optical structure 10. In some embodiments, the light source LS emits light of a single wavelength, for example, light of a wavelength of about 850 nm, about 940 nm, about 1350 nm, or about 1550 nm. In some embodiments, the light source LS emits light of multiple wavelengths, for example, light of a wavelength of about 850 ± 5 nm, about 940 ± 5 nm, about 1350 ± 5 nm, or about 1550 ± 5 nm. In some embodiments, the light source LS can be a Vertical-Cavity Surface-Emitting Laser (VCSEL).

[0103] Referring to Figure 2 , according to an embodiment of the present disclosure, an optical structure 10 is provided. Figure 2 FIG. 1 is a schematic cross-sectional view of an optical structure 10.

[0104] In Figure 2 some embodiments, a portion of the optical structure 10 is similar to the optical structure 10 of Figure 1 FIG. 1. In Figure 2 some embodiments, the optical structure 10 is similar to the optical structure 10 ofIn some embodiments, the sensor 12 is connected to a printed circuit board (PCB) 36 by solder balls 40. That is, the optical structure 10 is packaged in a chip scale package (CSP). A packaging material 41 is disposed between the substrate 18 and the glass substrate 26, leaving a space 30. In some embodiments, the height H of the chip scale package (CSP) of the optical structure 10 is less than about 1.2 cm. In addition, a light source LS is disposed above the optical structure 10. In some embodiments, the light source LS emits light of a single wavelength, for example, light of a wavelength of about 850 nm, about 940 nm, about 1350 nm, or about 1550 nm. In some embodiments, the light source LS emits light of multiple wavelengths, for example, light of a wavelength of about 850 ± 5 nm, about 940 ± 5 nm, about 1350 ± 5 nm, or about 1550 ± 5 nm. In some embodiments, the light source LS can be a vertical-cavity surface-emitting laser (VCSEL).

[0105] Referring to Figure 3 , according to an embodiment of the present application, an optical structure 10 is provided. Figure 3 FIG. 1 is a schematic diagram of a cross-sectional view of the optical structure 10.

[0106] In Figure 3 , the optical structure 10 includes a sensor 12, a bandpass filter 14, and a plurality of protrusions 16. The bandpass filter 14 is disposed above the sensor 12. The protrusions 16 are disposed on the bandpass filter 14.

[0107] The sensor 12 includes a substrate 18, a plurality of photoelectric conversion units 20, a plurality of color filters 22, and a plurality of microlenses 24. The photoelectric conversion units 20 are disposed in the substrate 18. The color filters 22 are disposed on the substrate 18 and correspond to the photoelectric conversion units 20, respectively. The microlenses 24 are disposed on the color filters 22 and correspond to the photoelectric conversion units 20, respectively.

[0108] In some embodiments, the substrate 18 can include a bulk semiconductor substrate, such as a semiconductor wafer. For example, the substrate 18 can include a silicon wafer. The substrate 18 can include silicon or other elemental semiconductor material, such as germanium. In some embodiments, the substrate 18 can include a compound semiconductor. The compound semiconductor can include gallium arsenide, silicon carbide, indium arsenide, indium phosphide, other suitable materials, or combinations of the foregoing. In some embodiments, the substrate 18 can include a semiconductor-on-insulator (SOI) substrate. The semiconductor-on-insulator substrate can be fabricated using separation by implantation of oxygen (SIMOX) processes, wafer bonding processes, other applicable methods, or combinations of the foregoing. In some embodiments, the substrate 18 can include an undoped substrate.

[0109] In some embodiments, the photoelectric conversion unit 20 can include an element that converts light into electrical energy, such as a photodiode (PD). In some embodiments, the color filter 22 can include an organic color filter or an inorganic color filter. In some embodiments, the color filter 22 can include a red filter, a green filter, a blue filter, or combinations of the foregoing.

[0110] In Figure 3 In some embodiments, the sensor 12 can include a complementary metal-oxide-semiconductor (CMOS) image sensor. In some embodiments, the sensor 12 can include other suitable sensors, such as a fingerprint sensor.

[0111] In some embodiments, the bandpass filter 14 can include a single layer or multiple layers. In some embodiments, the material of the bandpass filter 14 can include silicon hydride (SiH), silicon germanide (SiGe), germanium hydride (GeH), or combinations of the foregoing. In some embodiments, the bandpass filter 14 (i.e., a near-infrared bandpass filter) can allow light having a wavelength between about 700 nanometers and about 3000 nanometers to pass through. For example, the bandpass filter 14 can allow light of a single wavelength to pass through, such as light having a wavelength of about 850 nanometers, about 940 nanometers, about 1350 nanometers, or about 1550 nanometers, or the bandpass filter 14 can allow light of multiple wavelengths to pass through, such as light having a wavelength of about 850 ± 5 nanometers, about 940 ± 5 nanometers, about 1350 ± 5 nanometers, about 1550 ± 5 nanometers, or combinations of the foregoing.

[0112] In some embodiments, the protrusion 16 may comprise a high refractive index material having a refractive index between about 3.0 and about 5.0. In some embodiments, the material of the protrusion 16 may include titanium oxide (TiO2), silicon nitride (SiN), silicon oxide (SiO2), hydrogen silicide (SiH), or combinations thereof. The structure, shape, size, and configuration of the protrusion 16 will be described in detail below (e.g.). Figures 5-8 ).

[0113] exist Figure 3 In this optical structure 10, a low-refractive-index material layer 42 is also included. The low-refractive-index material layer 42 is disposed between the sensor 12 and the bandpass filter 14. In some embodiments, the low-refractive-index material layer 42 with an appropriate thickness is used, taking into account the path and travel distance of the incident light. Furthermore, the low-refractive-index material layer 42 can reduce the refractive index of the microlens 24 located below it.

[0114] exist Figure 3 In this optical structure 10, a polymer layer 44 is also included. The polymer layer 44 is disposed between the low refractive index material layer 42 and the bandpass filter 14. In some embodiments, a polymer layer 44 with an appropriate thickness is used, taking into account the path and travel distance of the incident light.

[0115] exist Figure 3 In this optical structure 10, a polymer layer 32 is further included to cover and protect the bandpass filter 14 and the protrusion 16 located beneath it. In some embodiments, the polymer layer 32 may comprise a polymer material with high transmittance and a refractive index between about 1.2 and about 2.0. The optical structure 10 also includes an anti-reflective layer 34 disposed on the polymer layer 32.

[0116] exist Figure 3In some embodiments, the sensor 12 is connected to a printed circuit board (PCB) 36 by wire bonding 38. That is, the optical structure 10 is packaged in a Chip On Board (COB) manner. A packaging material 45 covers a portion of the substrate 18 and the printed circuit board (PCB) 36, and encloses the low refractive material layer 42 and the elements formed on the low refractive material layer 42. In some embodiments, the height H of the Chip On Board (COB) packaging of the optical structure 10 is less than about 1 centimeter. In addition, a light source LS is disposed above the optical structure 10. In some embodiments, the light source LS emits light of a single wavelength, for example, light of a wavelength of about 850 nanometers, about 940 nanometers, about 1350 nanometers, or about 1550 nanometers. In some embodiments, the light source LS emits light of multiple wavelengths, for example, light of a wavelength of about 850 ± 5 nanometers, about 940 ± 5 nanometers, about 1350 ± 5 nanometers, or about 1550 ± 5 nanometers. In some embodiments, the light source LS can be a Vertical-Cavity Surface-Emitting Laser (VCSEL).

[0117] Referring to Figure 4 , according to an embodiment of the present disclosure, an optical structure 10 is provided. Figure 4 is a schematic view of a cross section of the optical structure 10.

[0118] In Figure 4 , a portion of the optical structure 10 is similar to the optical structure 10 of Figure 3 . In Figure 4 , the optical structure 10 further includes a plurality of second protrusions 46. The second protrusions 46 are disposed in the polymer layer 44. The structure, shape, size, and arrangement of the second protrusions 46 are similar to those of the protrusions 16, which are described in detail below (e.g., as shown in Figures 5-8 ).

[0119] In Figure 3 and Figure 4 , the optical structure 10 is packaged in a Chip On Board (COB) manner. In some embodiments, the optical structure 10 can also be packaged in a Chip Scale Package (CSP) manner, as shown in Figure 2 .

[0120] Hereinafter, the structure, shape, size, and arrangement of the protrusions 16 (i.e., metalenses) are described in detail, as shown in Figures 5-8 . Figures 5-7 is a top view of the protrusions 16 of the optical structure 10. Figure 8 shows the penetration of the protrusions 16 and the relationship between the size of the protrusions 16 and the phase of the incident light.

[0121] exist Figure 5 In this embodiment, the protrusion 16 includes a solid structure, such as a solid cylinder 48, a solid hexagonal prism 50, or a solid square prism 52. When the protrusion 16 is a solid cylinder 48, the diameter D of each protrusion 16 is between approximately 150 nanometers and approximately 300 nanometers. It is noteworthy that the diameter D is a subwavelength dimension. The solid hexagonal prism 50 and the solid square prism 52 are also subwavelength dimensions. "Subwavelength dimension" means that the size of each protrusion 16 is smaller than the wavelength of the applied light source. Furthermore, each protrusion 16 has a center C. A spacing P exists between the two centers C of adjacent protrusions 16. In some embodiments, the spacing P of the protrusions 16 is between approximately 100 nanometers and approximately 1000 nanometers. In some embodiments, when the light source emits single-wavelength light, for example, when emitting light with wavelengths of approximately 850 nanometers, approximately 940 nanometers, approximately 1350 nanometers, or approximately 1550 nanometers, it is suitable to use... Figure 5 The protrusion 16 shown has a solid structure.

[0122] exist Figure 6 In this design, the protrusion 16 comprises a hollow structure, such as a hollow cylinder 54, a hollow hexagonal prism 56, or a hollow square prism 58. The hollow cylinder 54 includes a first portion 54a and a space 54b, with the space 54b surrounded by the first portion 54a. The hollow hexagonal prism 56 includes a first portion 56a and a space 56b, with the space 56b surrounded by the first portion 56a. The hollow square prism 58 includes a first portion 58a and a space 58b, with the space 58b surrounded by the first portion 58a. When the protrusion 16 is a hollow cylinder 54, the diameter D of each protrusion 16 is between approximately 150 nanometers and approximately 300 nanometers. Notably, the diameter D is a subwavelength dimension. The hollow hexagonal prism 56 and the hollow square prism 58 are also subwavelength dimensions. Furthermore, each protrusion 16 has a center C. A spacing P exists between the two centers C of adjacent protrusions 16. In some embodiments, the spacing P of the protrusions 16 is between approximately 100 nanometers and approximately 1000 nanometers. In some embodiments, when the light source emits light of multiple wavelengths, for example, when emitting light with wavelengths of approximately 850 ± 5 nanometers, approximately 940 ± 5 nanometers, approximately 1350 ± 5 nanometers, or approximately 1550 ± 5 nanometers, it is suitable to use... Figure 6 The protrusion 16 shown has a hollow structure.

[0123] exist Figure 7In some embodiments, the protrusions 16 include a hollow structure, such as a hollow cylinder 60, a hollow hexagonal cylinder 62, or a hollow square cylinder 64. The hollow cylinder 60 includes a first portion 60a, a space 60b, and a second portion 60c, the second portion 60c being surrounded by the space 60b, and the space 60b being surrounded by the first portion 60a. The hollow hexagonal cylinder 62 includes a first portion 62a, a space 62b, and a second portion 62c, the second portion 62c being surrounded by the space 62b, and the space 62b being surrounded by the first portion 62a. The hollow square cylinder 64 includes a first portion 64a, a space 64b, and a second portion 64c, the second portion 64c being surrounded by the space 64b, and the space 64b being surrounded by the first portion 64a. When the protrusions 16 are the hollow cylinders 60, the diameter D of each protrusion 16 is between about 150 nm and about 300 nm. Notably, the diameter D is a subwavelength dimension. The hollow hexagonal cylinders 62 and the hollow square cylinders 64 are also subwavelength dimensions. In addition, each protrusion 16 has a center C. The distance P between the centers C of adjacent protrusions 16 is between about 100 nm and about 1000 nm in some embodiments. In some embodiments, the protrusions 16 with hollow structures as shown in FIG. 6 are suitable for use when the light source emits light of multiple wavelengths, such as when emitting light of wavelengths of about 850 ± 5 nm, about 940 ± 5 nm, about 1350 ± 5 nm, or about 1550 ± 5 nm. In fact, the light passing through the protrusions 16 can include single or multiple wavelengths of light within a certain wavelength range (about 700 nm to about 3000 nm), where the protrusions 16 provided as solid or hollow (as shown in FIG. 5) can effectively reduce dispersion (aberration) in the above cases. Figure 7 Figures 5-7

[0124] Figures 5-7 The protrusions 16 disclosed disposed on the bandpass filter 14 include metalenses. In some embodiments, the protrusions 16 can include Fresnel lenses.

[0125] See Figure 8 for the optical effects produced by the size distribution of the protrusions 16. The test conditions are as follows: the wavelength of the incident light is 940 nm. The protrusions 16 are solid cylinders. The protrusions 16 are disposed on the bandpass filter 14 in an array. The diameter of the protrusions 16 is between about 150 nm and about 300 nm. The distance between the protrusions 16 is 500 nm. As shown in FIG. 7, the bandpass filter 14 with the protrusions 16 disposed thereon has a transmission spectrum 70. The transmission spectrum 70 includes a first peak 71, a second peak 72, and a third peak 73. The first peak 71 is at about 940 nm. The second peak 72 is at about 850 nm. The third peak 73 is at about 1350 nm. The bandpass filter 14 without the protrusions 16 disposed thereon has a transmission spectrum 80. The transmission spectrum 80 includes a first peak 81 and a second peak 82. The first peak 81 is at about 940 nm. The second peak 82 is at about 850 nm. The bandpass filter 14 with the protrusions 16 disposed thereon has a transmission spectrum 70 that is different from the transmission spectrum 80 of the bandpass filter 14 without the protrusions 16 disposed thereon. In other words, the transmission spectrum 70 of the bandpass filter 14 with the protrusions 16 disposed thereon is different from the transmission spectrum 80 of the bandpass filter 14 without the protrusions 16 disposed thereon. Figure 8 ​​As shown, the size distribution of the protrusions 16 (diameter of about 150 nm to about 300 nm) controls the phase of the incident light to be between 0 and 2π (as curve A), which achieves optical steerability and controllable wave behavior. In addition, the protrusions 16 have a penetration of more than 80%, eliminating the effects of reflection and refraction.

[0126] In addition, it is also proved that the protrusions 16 have a focusing function (similar to a traditional module lens), for example, with a focal length of about 1 cm. According to product requirements, different focusing lengths can be designed.

[0127] Referring to Figures 9A-9N According to an embodiment of the present application, a method for manufacturing an optical structure is provided. Figures 9A-9N FIG. 1 is a cross-sectional view of a method for manufacturing an optical structure.

[0128] Referring to Figure 9A The glass substrate 26 is provided.

[0129] Referring to Figure 9B A first bandpass filter 14 is formed on a top side 26a of the glass substrate 26, and a second bandpass filter 28 is formed on a bottom side 26b of the glass substrate 26. In some embodiments, the first bandpass filter 14 and the second bandpass filter 28 can be formed on the top side 26a and the bottom side 26b of the glass substrate 26, respectively, by, for example, sputtering, spin coating, chemical vapor deposition (CVD), low pressure chemical vapor deposition (LPCVD), low temperature chemical vapor deposition (LTCVD), rapid thermal chemical vapor deposition (RTCVD), plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), physical vapor deposition processes, molecular beam deposition processes, any other suitable processes, or combinations thereof.

[0130] Referring to Figure 9C A material layer 16' is formed on the first bandpass filter 14. In some embodiments, the material layer 16' can be formed on the first bandpass filter 14 by, for example, sputtering, spin coating, chemical vapor deposition (CVD), low pressure chemical vapor deposition (LPCVD), low temperature chemical vapor deposition (LTCVD), rapid thermal chemical vapor deposition (RTCVD), plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), physical vapor deposition processes, molecular beam deposition processes, any other suitable processes, or combinations thereof. In some embodiments, the material of the material layer 16' can include a dielectric material, such as titanium oxide (TiO2), silicon nitride (SiN), silicon oxide (SiO2), silicon hydride (SiH), or combinations thereof.

[0131] Referring to Figures 9D-9FThe material layer 16' is patterned by a lithography process to form a plurality of protrusions 16.

[0132] Referring to Figure 9D A photoresist layer 66 is formed on the material layer 16'. In some embodiments, the photoresist layer 66 can be formed on the material layer 16' by, for example, sputtering, spin coating, chemical vapor deposition (CVD), low pressure chemical vapor deposition (LPCVD), low temperature chemical vapor deposition (LTCVD), rapid thermal chemical vapor deposition (RTCVD), plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), physical vapor deposition, molecular beam deposition, any other suitable process, or a combination thereof.

[0133] In some embodiments, the photoresist layer 66 can include a photoresist material that is sensitive to a radiation source, such as a positive-tone photoresist material or a negative-tone photoresist material. The photoresist layer 66 can have a multi-layer structure. Further, the photoresist layer 66 can be implemented with a chemical amplification (CA) photoresist material. A positive-tone chemical amplification (CA) photoresist material refers to a polymer material that is soluble in a developer after exposure to an acidic portion. A negative-tone chemical amplification (CA) photoresist material refers to a polymer material that is insoluble in a developer after exposure to an acidic portion.

[0134] The photoresist layer 66 is exposed to a radiation source 68 through a mask 70 having a pattern. In some embodiments, the radiation source 68 can include i-line radiation, deep ultraviolet (DUV) radiation, and / or extreme ultraviolet (EUV) radiation.

[0135] Referring to Figure 9E After the exposure process, a post-exposure bake and a development process are performed on the photoresist layer 66 to form a patterned photoresist layer 66'. The patterned photoresist layer 66' serves as an etch mask for an etching process.

[0136] Referring to Figure 9F The material layer 16' is etched using a suitable etchant and by, for example, reactive ion etching, neutral beam etching, or other similar methods to form the protrusions 16. The lithography process can achieve high-resolution patterning and better process stability.

[0137] The material layer 16' can also be selectively patterned by a nanoimprint process to form the plurality of protrusions 16.

[0138] For example, a resin layer is formed on the material layer 16'. In some embodiments, the resin layer can be formed on the material layer 16' by, for example, sputtering, spin coating, chemical vapor deposition (CVD), low pressure chemical vapor deposition (LPCVD), low temperature chemical vapor deposition (LTCVD), rapid thermal chemical vapor deposition (RTCVD), plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), physical vapor deposition, molecular beam deposition, any other suitable process, or a combination thereof.

[0139] In some embodiments, the material of the resin layer can include a thermoplastic polymer or an ultraviolet light curable resin. The thermoplastic polymer can include polyethylene (PE), polypropylene (PP), polystyrene (PS), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), nylon, polycarbonate (PC), polyurethane (PU), polytetrafluoroethylene (PTFE, also known as Teflon), polyethylene terephthalate (PET), or a combination thereof. The ultraviolet light curable resin can include epoxy acrylate, acrylated polyester, acrylated urethane, acrylated silicone, or a combination thereof.

[0140] Next, a mold having a pattern is applied to the resin layer. Thereafter, the resin layer is subjected to a curing process by heating or ultraviolet light, depending on the material of the resin layer. After the mold is removed, a patterned resin layer is formed. The patterned resin layer serves as an etching mask for an etching process.

[0141] Next, the material layer 16' is etched using a suitable etchant and by, for example, reactive ion etching, neutral beam etching, or other similar methods to form the protrusions 16. Nanoimprint can achieve higher process throughput.

[0142] See, for example, U.S. Patent No. 6,375,540, which is incorporated herein by reference in its entirety. Figure 9GA polymer layer 32 is formed on the first bandpass filter 14 and the protrusion 16 such that the protrusion 16 is not exposed from the polymer layer 32. In some embodiments, the polymer layer 32 can be formed on the first bandpass filter 14 and the protrusion 16 by, for example, sputtering, spin coating, chemical vapor deposition (CVD), low pressure chemical vapor deposition (LPCVD), low temperature chemical vapor deposition (LTCVD), rapid thermal chemical vapor deposition (RTCVD), plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), physical vapor deposition, molecular beam deposition, any other suitable process, or a combination thereof. In some embodiments, the polymer layer 32 can include a polymer material having a high-transmittance with a refractive index between about 1.2 and about 2.0.

[0143] Referring to Figure 9H An anti-reflective layer 34 is formed on the polymer layer 32. In some embodiments, the anti-reflective layer 34 can be formed on the polymer layer 32 by, for example, sputtering, spin coating, chemical vapor deposition (CVD), low pressure chemical vapor deposition (LPCVD), low temperature chemical vapor deposition (LTCVD), rapid thermal chemical vapor deposition (RTCVD), plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), physical vapor deposition, molecular beam deposition, any other suitable process, or a combination thereof.

[0144] Referring to Figure 9I A substrate 18 is provided, which includes a plurality of photoelectric conversion units 20.

[0145] Referring to Figure 9J A plurality of color filters 22 are formed on the substrate 18 and correspond to the photoelectric conversion units 20, respectively. A plurality of microlenses 24 are formed on the color filters 22 and correspond to the photoelectric conversion units 20, respectively.

[0146] Referring to Figure 9K The substrate 18 is connected to a printed circuit board (PCB) 36 by wire bonding 38.

[0147] Referring to Figure 9L A packaging material 39 is formed to cover a portion of the substrate 18 and the printed circuit board (PCB) 36.

[0148] Referring to Figure 9M The structure of Figure 9H is bonded to the structure of Figure 9L with the space 30.

[0149] Referring to FIG. 9N, a structure is provided in which the encapsulation material 39 surrounds Figure 9H . At this point, the optical structure 10 is completed. Figure 1

[0150] Referring to FIG. 9N, a structure is provided in which the encapsulation material 39 surrounds Figures 10A-10D , according to an embodiment of the present invention, a method of manufacturing an optical structure is provided. Figures 10A-10D is a cross-sectional view of the method of manufacturing an optical structure.

[0151] Referring to FIG. 9N, a structure is provided in which the encapsulation material 39 surrounds Figure 10A . The substrate 18 is provided, which includes a plurality of photoelectric conversion units 20.

[0152] Referring to FIG. 9N, a structure is provided in which the encapsulation material 39 surrounds Figure 10B . A plurality of color filters 22 are formed on the substrate 18, and correspond to the photoelectric conversion units 20, respectively. A plurality of microlenses 24 are formed on the color filters 22, and correspond to the photoelectric conversion units 20, respectively.

[0153] Referring to FIG. 9N, a structure is provided in which the encapsulation material 39 surrounds Figure 10C . The encapsulation material 41 is formed to cover a portion of the substrate 18. Thereafter, a structure is bonded on the encapsulation material 41, leaving the space 30. Figure 9H

[0154] Referring to FIG. 9N, a structure is provided in which the encapsulation material 39 surrounds Figure 10D . The substrate 18 is connected to the printed circuit board (PCB) 36 through the solder balls 40. At this point, the optical structure 10 is completed. Figure 2

[0155] Referring to FIG. 9N, a structure is provided in which the encapsulation material 39 surrounds Figures 11A-11L , according to an embodiment of the present invention, a method of manufacturing an optical structure is provided. Figures 11A-11L is a cross-sectional view of the method of manufacturing an optical structure.

[0156] Referring to FIG. 9N, a structure is provided in which the encapsulation material 39 surrounds Figure 11A . The substrate 18 is provided, which includes a plurality of photoelectric conversion units 20.

[0157] Referring to FIG. 9N, a structure is provided in which the encapsulation material 39 surrounds Figure 11B . A plurality of color filters 22 are formed on the substrate 18, and correspond to the photoelectric conversion units 20, respectively. A plurality of microlenses 24 are formed on the color filters 22, and correspond to the photoelectric conversion units 20, respectively.

[0158] Referring to FIG. 9N, a structure is provided in which the encapsulation material 39 surrounds Figure 11C ​​​A low refractive index material layer 42 is formed on the substrate 18, covering the color filter 22 and the microlens 24. Thereafter, a polymer layer 44 is formed on the low refractive index material layer 42. In some embodiments, the low refractive index material layer 42 and the polymer layer 44 can be formed by, for example, sputtering, spin coating, chemical vapor deposition (CVD), low pressure chemical vapor deposition (LPCVD), low temperature chemical vapor deposition (LTCVD), rapid thermal chemical vapor deposition (RTCVD), plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), physical vapor deposition, molecular beam deposition, any other suitable process, or a combination thereof.

[0159] Referring to Figure 11D A bandpass filter 14 is formed on the polymer layer 44. In some embodiments, the bandpass filter 14 can be formed on the polymer layer 44 by, for example, sputtering, spin coating, chemical vapor deposition (CVD), low pressure chemical vapor deposition (LPCVD), low temperature chemical vapor deposition (LTCVD), rapid thermal chemical vapor deposition (RTCVD), plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), physical vapor deposition, molecular beam deposition, any other suitable process, or a combination thereof.

[0160] Referring to Figure 11E A material layer 16' is formed on the bandpass filter 14, which is similar to that shown in Figure 9C

[0161] Referring to Figures 11F-11H The material layer 16' is patterned by a lithography process to form a plurality of protrusions 16, which is similar to that shown in Figures 9D-9F Likewise, the material layer 16' can also be patterned by a nanoimprint process to form a plurality of protrusions 16, which is similar to the related processes described above.

[0162] Referring to Figure 11I A polymer layer 32 is formed on the bandpass filter 14 and the protrusions 16, such that the protrusions 16 are not exposed from the polymer layer 32, which is similar to that shown in Figure 9G

[0163] Referring to Figure 11J An anti-reflective layer 34 is formed on the polymer layer 32, which is similar to that shown in Figure 9H

[0164] Referring to Figure 11K The substrate 18 is connected to a printed circuit board (PCB) 36 by wire bonding 38.​​​

[0165] Referring to Figure 11L , a packaging material 45 is formed to cover and surround a portion of the substrate 18, the elements formed on the substrate 18, and a printed circuit board (PCB) 36. At this point, the optical structure 10 is completed. Figure 3

[0166] The present disclosure replaces the conventional vertically stacked module lens with a planar lens (e.g., metalenses or Fresnel lenses). When the planar lens is integrated with a bandpass filter on a glass substrate with an appropriate thickness and packaged in a chip-on-board (COB) manner, the height of the overall packaging structure can be reduced to less than about 2 cm. When the planar lens is integrated with a bandpass filter on a glass substrate with an appropriate thickness and packaged in a chip-scale package (CSP) manner, the height of the overall packaging structure can be reduced to less than about 1.2 cm, and the packaging size in the X-Y direction can also be miniaturized. When the planar lens is integrated with a bandpass filter on a chip through wafer processing and packaged in a chip-on-board (COB) manner, the height of the overall packaging structure can be reduced to less than about 1 cm. The optimal size distribution of the planar lens controls the phase of the incident light to be between 0 and 2π, which achieves optical manipulability and controls the behavior of the wave. In addition, the planar lens has a transmittance of more than 80%, eliminating the effects of reflection and refraction. The planar lens has a focusing function, which is also sufficient to indicate that it can replace the conventional vertically stacked module lens. Furthermore, solid or hollow planar lenses can cope with the case where the light passing through the planar lens can contain single or multiple wavelengths, effectively reducing dispersion (aberration).

[0167] While the embodiments of the disclosure and the advantages thereof have been disclosed, it should be understood that various modifications, substitutions, and changes can be made, which are within the spirit and range of the disclosure and the disclosure is not restricted to the described particular embodiments. In addition, it is expressly intended that all such modifications, substitutions, and changes be included as being within the scope of the disclosure, and as such have been contemplated by the present disclosure. It is therefore intended that the protection afforded the disclosure is to be construed as including all such modifications, substitutions, and changes insofar as they come within the scope of the current disclosure.​

Claims

1. An optical structure comprising: One sensor; A first bandpass filter is disposed above the sensor; A second bandpass filter is disposed above the sensor, wherein the first bandpass filter is disposed on the second bandpass filter; A glass substrate is disposed between the first bandpass filter and the second bandpass filter; Multiple first protrusions are disposed on the first bandpass filter; A first polymer layer covering the first bandpass filter and the first protrusion; and An anti-reflective layer is disposed on the first polymer layer; A low-refractive-index material layer is disposed between the sensor and the first bandpass filter; A second polymer layer is disposed between the low-refractive-index material layer and the first bandpass filter; and Multiple second protrusions are disposed in the second polymer layer.

2. The optical structure of claim 1, wherein the first bandpass filter allows light with wavelengths between 700 nm and 3000 nm to pass through.

3. The optical structure of claim 1, wherein the protrusion comprises a cylinder, a hexagonal prism, or a square prism, at least one protrusion comprises a first portion and a space surrounded by the first portion, and the at least one protrusion further comprises a second portion surrounded by the space.

4. The optical structure of claim 1, wherein the protrusions are cylindrical, each protrusion has a diameter between 150 nm and 300 nm, the spacing between the protrusions is between 100 nm and 1000 nm, and the protrusions have a size distribution that controls the phase of the incident light to be between 0 and 2π.

5. The optical structure of claim 1, wherein the protrusion comprises titanium oxide, silicon nitride, silicon oxide, hydrogen silicide, or a combination thereof, having a refractive index between 3.0 and 5.

0.

6. The optical structure of claim 1, wherein the thickness of the glass substrate is between 50 micrometers and 500 micrometers.

7. The optical structure of claim 6 further includes a space located between the sensor and the glass substrate, wherein a low refractive index material, a positive refractive index material, or a combination thereof is filled in the space.

8. The optical structure of claim 1, wherein the sensor comprises a complementary metal-oxide-semiconductor image sensor or a fingerprint sensor, connected to a printed circuit board via wire bonding.

9. The optical structure of claim 1, wherein the sensor comprises a complementary metal-oxide-semiconductor image sensor or a fingerprint sensor, connected to a printed circuit board via solder balls.

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