Optical package with stacked integrated filter

Abstract

The present disclosure relates to an optical package with stacked integrated filters. An optical filter package (100, Fig. 1) can include a glass plate (104) having a first surface (106) and a second surface (108) opposite the first surface, where the first surface has a first filter (110) and the second surface has a second filter (112) different from the first filter. The optical filter package can include a semiconductor die (114) including a light sensor (115) having a third surface (116) and a fourth surface (118) opposite the third surface, where at least a portion of the third surface has a third filter (120). The optical filter package can further include an optically transparent adhesive (122) in contact with the second surface of the glass plate and the third surface of the semiconductor die.

Description

Technical Field

[0001] This disclosure relates to an optical package with stacked integrated filters. Background Technology

[0002] A semiconductor die with a light sensor is an integrated chip (IC) that detects the intensity of ambient light in various environments. It typically consists of a photodetector (which converts light into an electrical signal) and associated circuitry (which processes the electrical signal and outputs relevant data). It is often integrated into a broader system-on-a-chip (SoC) solution to ensure minimal space usage while providing reliable performance for automatic brightness control and other light-sensitive applications. Such semiconductor dies are commonly used in light sensor systems to adjust screen brightness in electronic devices such as smartphones, tablets, and automotive displays, thereby optimizing visibility and power consumption. Summary of the Invention

[0003] In one example, the optical filter package includes a semiconductor die with a light sensor. Glass plates with different filters on opposing surfaces are attached to the semiconductor die by an optically transparent adhesive. At least a portion of the surface of the semiconductor die in contact with the optically transparent adhesive has one or more other filters.

[0004] In another example, the integrated optical filter package includes a semiconductor die containing a photosensor. The semiconductor die is attached to a substrate by an adhesive. Glass plates with different filters on opposing surfaces are attached to the semiconductor die by an optically transparent adhesive. At least a portion of the surface of the semiconductor die in contact with the optically transparent adhesive has one or more other filters. An optically opaque molding compound circumferentially surrounds the glass plates and the semiconductor die, such that one of the surfaces of the glass plates is exposed to ambient light. The semiconductor die is electrically coupled to the substrate by wire bonding.

[0005] In another example, a method for manufacturing an integrated optical filter package includes: attaching an optically transparent adhesive film to a glass wafer having different filters on opposing surfaces; dicing the glass wafer into individual glass plates, each glass plate having a portion of the optically transparent adhesive film; and placing the glass plates on the top surface of an assembly including a semiconductor die having a photosensor, such that the surface of the semiconductor die adjacent to the glass plate includes at least one other filter attached thereto, and a portion of the optically transparent adhesive film is located between the surfaces of the glass plate and the semiconductor die. Pressure can then be applied to the exposed surfaces of the glass plates, and the temperature can be increased until the portion of the optically transparent adhesive film is cured. The semiconductor die can be electrically bonded to a substrate, for example, by wire bonding. An optically opaque molding compound can be applied along the outer periphery of the semiconductor die and the glass plate, and subsequently cured. Attached Figure Description

[0006] The examples will be readily understood through the following detailed description taken in conjunction with the accompanying drawings. For ease of description, the same reference numerals designate the same parts. The aspects are illustrated in the figures by way of example rather than limitation.

[0007] Figure 1 This is a simplified cross-sectional view illustrating an example optical filter package with stacked integrated filters.

[0008] Figures 2A to 2B Simplified diagrams are provided to illustrate the plan view and cross-sectional view of an example optical filter package with stacked integrated filters, respectively.

[0009] Figure 3 A simplified side view of the glass plate used in an example optical filter package with stacked integrated filters.

[0010] Figure 4 A simplified side view of the glass plate used in an example optical filter package with stacked integrated filters.

[0011] Figure 5 A simplified side view of the glass plate used in an example optical filter package with stacked integrated filters.

[0012] Figures 6A to 6C A simplified diagram of an example glass plate used in an example optical filter package with stacked integrated filters.

[0013] Figure 7 A simplified side view of the glass plate used in an example optical filter package with stacked integrated filters.

[0014] Figure 8 A simplified side view of the glass plate used in an example optical filter package with stacked integrated filters.

[0015] Figure 9 A simplified plan view of the glass plate used in an example optical filter package with stacked integrated filters.

[0016] Figure 10 A simplified plan view of some components of an example optical filter package with stacked integrated filters.

[0017] Figure 11 This is a simplified cross-sectional view illustrating an example optical filter package with stacked integrated filters.

[0018] Figure 12 This is a simplified cross-sectional view illustrating an example optical filter package with stacked integrated filters.

[0019] Figure 13 This is a simplified cross-sectional view illustrating an example optical filter package with stacked integrated filters.

[0020] Figure 14 This is a simplified cross-sectional view illustrating an example optical filter package with stacked integrated filters.

[0021] Figure 15 This is a simplified flowchart illustrating an example operation associated with manufacturing an optical filter package with stacked integrated filters. Detailed Implementation

[0022] For the purpose of illustrating the examples described herein, it is important to understand certain terminology and operations related to semiconductor packaging. The following basic information can be considered the basis for the proper interpretation of the various technical aspects described in this disclosure. Such information is provided for illustrative purposes only and therefore should not be construed in any way as limiting the broad scope of the techniques presented herein and their potential applications.

[0023] In the following detailed description, various aspects of the illustrative implementation scheme may be described using terminology commonly employed by those skilled in the art to convey the essence of their work to other skilled in the art.

[0024] The term "integrated circuit" (also known as IC) refers to a circuit integrated into a single piece of semiconductor or similar material. "Bare die" or "semiconductor bare die" refers to a piece of semiconductor or similar material (e.g., silicon, gallium nitride, etc.) containing an IC or other electronic component. The terms "package" and "IC package" are synonymous, just as the terms "bare die" and "IC bare die" are synonymous. It should be noted that the terms "chip," "bare die," and "IC bare die" are used interchangeably herein.

[0025] The terms “circuit” and “circuit system” refer to one or more passive and / or active electrical and / or electronic components arranged to cooperate with each other to provide a desired function. The terms also refer to analog circuit systems, digital circuit systems, hardwired circuit systems, optical circuit systems, programmable circuit systems, microcontroller circuit systems, and / or any other type of physical hardware, electrical and / or electronic components.

[0026] The term "package substrate" or "substrate" can be used to describe any substrate material that facilitates the packaging of any assembly of semiconductor dies and / or other electrical components, such as passive electrical components. As used herein, a package substrate can be made of any material, including but not limited to insulating materials such as resin-impregnated glass fiber (e.g., PCB), glass, ceramics, silicon, silicon carbide, aluminum nitride, alumina, etc. Additionally, as used herein, a package substrate can refer to a substrate comprising a multilayer (e.g., an ABF layer). Furthermore, a package substrate may include a conductive lead frame with lead fingers. In other instances, a package substrate may include discrete conductive tabs (e.g., die pads, bonding pads, lead fingers, etc.) embedded in a dielectric material (e.g., molding compounds and polyimide films). The package may also include an organic or inorganic passivation layer between the bare die and the substrate.

[0027] The term "filter" or "optical filter" refers to a component or material designed to selectively transmit, block, or modify the intensity, wavelength, and angular distribution of light passing through it. Filtering functionality is achieved by utilizing various optical mechanisms such as absorption, reflection, diffraction, or transmission. Optical filters can include color filters (e.g., colored glass), interference coatings, diffusers, micropores, and microlenses. For example, diffuse filters scatter light to produce a uniform or diffused pattern; micropore filters can filter specific wavelengths, intensities, or angles (e.g., directions) of light based on aperture size and spacing; color filters can allow only a specific range of wavelengths of light to pass through while blocking or absorbing other wavelengths.

[0028] As used herein, the term "light" refers to electromagnetic waves with wavelengths ranging from approximately 200 nanometers to 1 millimeter. This includes the near-ultraviolet, visible (e.g., light visible to the average human eye), and infrared (IR) wavelength ranges. The spectrum has the following approximate wavelength ranges for different colors and IR: Near-ultraviolet: 200 to 400 nanometers; Violet: 380 to 450 nanometers; Blue: 450 to 495 nanometers; Green: 495 to 570 nanometers; Yellow: 570 to 590 nanometers; Orange: 590 to 620 nanometers; Red: 620 to 750 nanometers; IR: 750 nanometers to 1 millimeter. Therefore, for example, when referring to a green filter, it can be understood that a color filter allows light in the wavelength range of approximately 495 to 570 nanometers to pass through while absorbing or blocking light outside this range. Similarly, an IR filter allows light in the wavelength range of approximately 750 nanometers to 1 millimeter to pass through while absorbing or blocking light of other wavelengths. Near-ultraviolet filters allow light in the wavelength range of approximately 200 nanometers to 400 nanometers to pass through, while absorbing or blocking light of other wavelengths.

[0029] The terms “generally,” “close to,” “approximately,” “nearly,” and “about” generally refer to a target value within + / - 20% (e.g., within + / - 5% or 10% of the target value) based on the context of a specific value as described herein or known in the field.

[0030] Terms indicating the orientation of various elements, such as “coplanar,” “perpendicular,” “orthogonal,” “parallel,” or any other angle between elements, generally refer to a context based on a specific value as described herein or as known in the field, within the range of + / - 5% to 20% of the target value.

[0031] The term “connection” refers to a direct connection between connected things (which may be one or more mechanical, electrical and / or thermal connections) without any intermediate means, while the term “coupling” refers to a direct connection between connected things or an indirect connection through one or more passive or active intermediate means.

[0032] The description uses the phrases "in one embodiment" or "in an embodiment," which may each refer to one or more of the same or different embodiments. The terms "embodiment," "aspect," and "example" are used interchangeably herein to describe a particular version, alternative, construction, implementation, configuration, arrangement, method, process, etc.

[0033] Where the terms “a,” “an,” “first,” or “another” or their equivalents are used in this disclosure or the claims, they should be interpreted as including one or more such elements, neither requiring nor excluding two or more such elements. Furthermore, the terms “comprising,” “including,” “having,” etc., as used with respect to embodiments of this disclosure are synonymous. With regard to the use of the term “comprising” in the detailed description or claims, this term is intended to be inclusive in a manner similar to the term “comprising,” as interpreted when “comprising” is used as a transitional word in the claims. The term “based on” is interpreted as meaning at least partially based on.

[0034] This disclosure may use perspective-based descriptions, such as “above,” “below,” “top,” “bottom,” and “side”; such descriptions are used for ease of discussion and are not intended to limit the application of the disclosed embodiments.

[0035] As used herein, the terms “above,” “below,” “between,” and “up” refer to the relative position of a material layer or component with respect to other layers or components. For example, a layer above or below another layer may be in direct contact with that layer or may have one or more intervening layers. Similarly, a layer between two layers may be in direct contact with one or both of the two layers or may have one or more intervening layers. Likewise, unless explicitly stated otherwise, a feature between two features may be in direct contact with an adjacent feature or may have one or more intervening layers.

[0036] When a reference measurement range is used, the term "between" includes the endpoints of the measurement range.

[0037] While certain elements may be referred to in the singular form herein, such elements may comprise multiple sub-elements. For example, "conductive material" may comprise one or more conductive materials. In another instance, "dielectric material" may comprise one or more dielectric materials.

[0038] Unless otherwise specified, the use of ordinal adjectives such as “first,” “second,” and “third” to describe common objects merely indicates different instances of similar objects and is not intended to imply that the objects described in this way must be in a given order in time, space, hierarchy, or in any other way.

[0039] In the following detailed description, reference is made to the accompanying drawings, which form part of this document and illustrate practical embodiments by way of illustration. It should be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of this disclosure. Therefore, the following detailed description should not be considered limiting.

[0040] The accompanying drawings are not necessarily drawn to scale. In the drawings, the same reference numerals refer to the same or similar elements / materials shown, such that, unless otherwise stated, the interpretation of an element / material with a given reference numeral in the context of one drawing also applies to other drawings in which elements / materials with the same reference numerals can be illustrated. Furthermore, the singular and plural forms of the labels may be used with the reference numerals to respectively indicate single and multiple elements of the same or similar type, kind, or category.

[0041] Furthermore, in the accompanying drawings, some schematic illustrations of the example structures of the various devices and assemblies described herein may be shown with precise right angles and straight lines. However, it should be understood that such schematic illustrations may not reflect real-world manufacturing constraints that could cause features to appear less than "ideal" when examined using suitable characterization tools, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), or non-contact surface profilometers. Possible processing and / or surface defects may also be visible in such images of real structures, such as surface roughness, curvature or profile deviations, pits or scratches, imperfectly straight edges of material, tapered through-holes or other openings, unintentional rounding or thickness variations at corners of different material layers, random spirals within crystalline regions, edge or combined dislocations, and / or random dislocation defects of individual atoms or clusters of atoms. Other defects not listed herein but common in the fields of device manufacturing and / or packaging may also exist. All such non-idealized and real possibilities are intended to be included within the scope of the various examples described herein.

[0042] It should be noted that in the accompanying drawings, various components are shown aligned (e.g., at corresponding interfaces) for illustrative purposes only; in reality, some or all of them may be misaligned. Additionally, other components, such as bonding pads, landing pads, metallization layers, etc., may be present in the assembly and are not shown in the figures to avoid clutter. Furthermore, these figures are intended to illustrate the relative arrangement of components within the assembly, and generally, such assemblies may contain other components not shown (e.g., various interface layers or other components related to optical functionality, electrical connectivity, or thermal mitigation). Also, although some components of the assembly are illustrated as planar rectangles or cuboids in the figures, this is only for illustrative purposes, and embodiments of these assemblies may be curved, rounded, or otherwise irregularly shaped, as specified by the manufacturing processes used to produce the various components and sometimes unavoidable due to said manufacturing processes.

[0043] In the accompanying drawings, a specific number and arrangement of structures and components are presented for illustrative purposes, and any desired number or arrangement of such structures and components may be present in various embodiments. It should also be noted that in the cross-sectional views, some components shown as being in contact with each other do not necessarily need to be in contact at all; the components may be located in different planes where the intervening material is removed. Therefore, unless specifically described as conductive coupling, surfaces shown as being in contact with each other may actually have intervening material, which is not shown for illustrative purposes.

[0044] Furthermore, unless otherwise specified, the structures shown in the accompanying drawings may take any suitable form or shape depending on the material properties, manufacturing process, and operating conditions.

[0045] For convenience, if there are sets of figures specified with different letters (e.g., Figures 6A to 6C If a set of reference numerals exists, the letter may be omitted in this document to refer to such a set (e.g., referred to as "Figure 6"). Similarly, if a set of reference numerals exists that are specified with different letters (e.g., 112a to 112e), the letter may be omitted in this document to refer to this set (e.g., referred to as "112").

[0046] Various operations can be described sequentially as multiple discrete actions or operations in a manner most conducive to understanding the claimed subject. However, the order of description should not be construed as implying that these operations necessarily depend on a specific order. In particular, these operations may not be performed in the order presented. The described operations may be performed in an order different from the described embodiments. Various additional operations may be performed, and / or the described operations may be omitted in other embodiments.

[0047] Optical filters are used in optical sensor systems to selectively transmit, block, or alter the wavelength, angle, and intensity (and other properties) of light, allowing the sensor to focus on specific portions of the spectrum and / or capture light energy in a particular manner. These filters improve sensor accuracy by eliminating unwanted light, enhancing the sensor's ability to detect specific light sources or environmental conditions. Common types of optical filters include bandpass filters (which allow only a narrow range of wavelengths to pass through), long-pass or short-pass filters (which block light with wavelengths shorter or longer than a specified cutoff wavelength), diffusers (which alter the angle of incident light), and so on.

[0048] Typically, filters are customized for specific applications. For example, optical sensor systems used in applications that detect a specific color have filters that remove wavelengths other than the wavelength of the color to be detected. Some applications require the removal of infrared light, and such sensors include infrared filters. In other applications, sensor systems are specifically designed for heat detection, and sensors in such applications include filters that remove all wavelengths except infrared wavelengths. In another application for fingerprint sensing, the filter may include pinholes (i.e., micropores) to partially block or collimate light incident on the sensor. In rare cases, more than one filter may exist as a separate component coupled within a single sensor system.

[0049] Semiconductor dies with integrated light sensors are commonly used in the sensor industry. Some sensor systems include one or two filters integrated into a package that houses the semiconductor die. In some such optical packages, the surface of the semiconductor die with the light sensor is exposed to incident light. The semiconductor die may have filters, such as microlenses for focusing or diffusing light, or color filters for filtering light of specific wavelengths. In some other such optical packages, a glass component with an integrated infrared filter, color filter, or micropore may be located on the surface of the semiconductor die.

[0050] Currently, sensor systems with integrated filters are limited in terms of filter combination due to constraints in materials, assemblies, and / or manufacturing. For example, wafer-level manufacturing can improve manufacturing efficiency, but it requires wire bonding of the semiconductor die for electrical connection, making wafer-level attachment impractical for these optical packages. Flip-chip bonding is also not feasible because the active area of ​​the die must be exposed to incident light, facing away from the package substrate, while flip-chip bonding requires the semiconductor die to be assembled with its active area facing the substrate. Furthermore, package-level assemblies can easily become inefficient. In such scenarios, mounting optical filters separately onto the semiconductor die can be cumbersome and require special handling (e.g., ensuring alignment), which can be prohibitively costly. Due to these additional costs and complexities, while optical sensors can be integrated with one or two filters in the package, depending on the end application, the additional filters are entirely located outside the device.

[0051] Figure 1 This is a simplified cross-sectional view of an example optical filter package 100 used in the optical sensor system 102. The optical filter package 100 includes a glass plate 104 having a first surface 106 and a second surface 108 opposite to the first surface 106. The first surface 106 has a first filter 110, and the second surface 108 has a second filter 112 different from the first filter 110. The optical package 100 further includes a semiconductor die 114 containing at least one light sensor 115. The light sensor 115 includes one or more electrical or photonic circuits for detecting, measuring, and / or otherwise manipulating light. The semiconductor die 114 has a third surface 116 adjacent to the second surface 108 and a fourth surface 118 opposite to the third surface 116. At least a portion of the third surface 116 has a color filter 120. An optically clear adhesive 122 contacts the second surface 108 of the glass plate 104 and the third surface 116 of the semiconductor die 114. In some instances, the color filter 120 may not have a uniform thickness on the third surface 116; in such cases, the optically transparent adhesive 122 may accommodate the resulting topological changes.

[0052] Optically opaque molding compound 124 circumferentially surrounds glass plate 104 and semiconductor die 114, exposing the first filter 110. Substrate 126 includes a first region 128 adjacent to a fourth surface 118 of semiconductor die 114. Substrate 126 further includes a second region 130 electrically coupled to semiconductor die 114 via wire bonding member 132. Adhesive 134 contacts (e.g., bonding, adhesive, etc.) substrate 126 and fourth surface 118 of semiconductor die 114. In some examples, adhesive 134 is a die-attachment adhesive comprising epoxy resin or polyimide. In some examples, such as the one shown in the figure, the first occupied area 136 of semiconductor die 114 may be larger than the second occupied area 138 of glass plate 104. Additionally, the outer peripheral edge 140 of the optically clear adhesive 122 may be substantially flush with the other outer peripheral edge 142 of the glass plate 104 (e.g., the area occupied by the optically clear adhesive 122 may be approximately equal to the area occupied by the glass plate 104 138).

[0053] In the illustrated example, the optical filter package 100 is a quad flat no-lead (QFN) package or a dual-sided flat no-lead (DFN) package, exposing regions 128 and 130 of the substrate 126 opposite to the first surface 106 of the glass plate 104. In some such examples, the first region 128 may include die pads (e.g., thermal die pads), and the second region 130 may include bonding pads. Various other package formats may also be used without departing from the scope of the examples described herein. The substrate 126 may be mounted to a PCB such that regions 128 and 130 of the substrate 126 opposite to the first surface 106 of the glass plate 104 are electrically and / or thermally bonded to the PCB. During operation, light may be incident on the first surface 106 and appropriately detected by circuitry in the semiconductor die 114.

[0054] In various embodiment examples, glass plate 104 is a homogeneous glass material that does not include individual fibers, such as those found in glass impregnation FR4. Examples of homogeneous glass materials for glass plate 104 include borosilicate glass, fused silica, aluminosilicate glass, soda-lime glass, etc. In various embodiments, the material of glass plate 104 may be selected to withstand high temperatures for curing polymeric materials in optical filter encapsulation 100, such as optically clear adhesive 122, optically opaque molding compound 124, or adhesive 134. Optically clear adhesive 122 may include commercially available epoxy resins, B-stage, optical die attach film (ODAF), lead overlay film material (FOW), or other optically clear polymeric adhesive materials. Optically opaque molding compound 124 may include epoxy resin materials compatible with optically clear adhesive 122 (e.g., those that do not chemically react with or penetrate it). In various embodiments, optically opaque molding compound 124 may be selected from commercially available off-the-shelf materials typically used in non-optical encapsulations based on specific requirements (e.g., to minimize cost).

[0055] In one particular embodiment, the first filter 110 may include a diffusion filter, and the second filter 112 may include a microporous filter, or vice versa. In another particular embodiment, the first filter 110 may include a diffusion filter, and the second filter 112 may include an infrared filter, or vice versa. In yet another particular embodiment, the first filter 110 may include a microporous filter, and the second filter 112 may include an infrared filter, or vice versa. A color filter 120 may filter one or more colors. The thickness of the color filter 120 may vary depending on the color of the light it is configured to filter and the amount of light it is configured to transmit or absorb. In various examples, the thickness of any one or more of the color filters 120 may vary between 0.5 micrometers and 15 micrometers. For example, a deep red filter may be thicker than a light yellow filter to block the same amount of light. The material of the green filter may be different from that of the red filter. In some instances, the color filter 120 may include more than one coating of material, or coatings of different materials, depending on the color to be filtered or the intensity of light to be attenuated or transmitted.

[0056] Furthermore, the materials and thicknesses of other optically transparent materials (such as glass plate 104, optically transparent adhesive 122, first filter 110, second filter 112, and color filter 120), as well as the types of filters in the first filter 110 and second filter 112, can be selected according to the desired optical requirements (e.g., the properties of light incident on the third surface 116 of the semiconductor die 114). For example, the thicknesses and materials of glass plate 104, optically transparent adhesive 122, first filter 110, second filter 112, and color filter 120, as well as the types of first filter 110 and second filter 112, can be selected so that light of a specific wavelength range and having a specific intensity range is incident on the third surface 116 at a specific angle range, so that the light is detected by the light sensor in the semiconductor die 114. In other words, the optical properties and thickness of the optically transparent adhesive 122, the first filter 110, the second filter 112, and the glass plate 104 can be selected so that the semiconductor die 114 measures the wavelength, intensity, and angle of light within a corresponding predetermined range. For example, the desired wavelength range can be between 300 and 1000 nanometers; the desired intensity range can be between 100 microlux and 100,000 lux. In some such examples, light with optical properties outside a certain range may not be detectable by the photosensitive sensor. In other examples, the selection of the thickness and materials of various components can be based on additional factors such as thermomechanical reliability (e.g., mitigating coefficient of thermal expansion (CTE) mismatch, reducing warpage during manufacturing and operation), cost, form factor (e.g., selecting thickness to keep the package height within a certain range), etc.

[0057] Figure 2A This is a simplified plan view of an example optical filter package 200 used in the optical sensor system 202. The optical filter package 200 is generally similar to the optical filter package 100. It should be noted that not all components of the optical filter package 200 are shown in the illustrated view. For example, the glass plate, optically transparent adhesive, optically opaque molding compound, and substrate are not shown, merely for illustrative purposes and not as a limitation. The third surface 204 of the semiconductor die 206 containing the light sensor (not shown for illustration) in the optical filter package 200 may have multiple color filters 208 to 218. In various embodiments, the color filters 208 to 218 may be deposited over the third surface 204 in one or more steps.

[0058] In one particular example, color filter 208 may be a green filter; color filter 210 may be a blue filter; color filter 212 may be a yellow filter; and so on. In the illustrated example view, color filters 208, 210, 212, 214, 216, and 218 are rectangular and arranged in an array, with each color filter separate from the others. In other examples, other configurations may be implemented. For example, each color filter 208 to 218 may be hexagonal and may be arranged in a planar honeycomb manner, with adjacent edges touching each other. In another example, each color filter 208 to 218 may be circular and irregularly distributed on the third surface 204. In yet another example, color filter 208 may be circular, and other color filters 210 to 218 may be concentrically distributed around color filter 208. Furthermore, although six color filters 208 to 218 are shown, this is merely for illustrative purposes; any number of color filters may be used in the optical filter package 200 without departing from the scope of the example. Various other such configurations may be used without departing from the scope of the example.

[0059] It should be noted that the wire bond 220 is shown on the outer peripheral edge of the semiconductor die 206. However, this is only for illustration purposes; in other instances, the wire bond 220 may be arranged on all four sides of the semiconductor die 206.

[0060] Figure 2B The diagram shows a cross-sectional view of an optical filter package 200 along the indicated plane. In various examples, color filters 208 to 218 may have different thicknesses. In the shown view, color filter 208 has a first thickness 222, and color filter 210 has a second thickness 224, the second thickness being greater than the first thickness 222. In some examples, the thickness range of the different color filters may vary between 50 nanometers and 500 nanometers. In some examples, each color filter may have a different number of coating layers. In one example, color filter 208 may include 10 coatings, each coating having a thickness varying between 0.2 micrometers and 1 micrometer, such that the first thickness 222 may vary between approximately 2 micrometers and 10 micrometers; color filter 210 may include 20 coatings, each coating having a thickness varying between 0.1 micrometers and 0.5 micrometers, such that the second layer thickness 224 may vary between approximately 2 micrometers and 10 micrometers. In some such examples, the first thickness 222 may be approximately 2 micrometers, and the second thickness 224 may be 10 micrometers. In another such example, the first thickness 222 may be approximately 5 micrometers, and the second thickness 224 may be 7 micrometers. Other color filters 212 to 218 may have coatings of corresponding different thicknesses and / or numbers of layers. Depending on the specific optical properties desired, each color filter 208 to 218 may also be made of different materials.

[0061] Figure 3 This is a simplified side view of a glass plate 300 used in the optical filter package 302 of the optical sensor system 304. In various embodiments, the glass plate 300 is generally similar to glass plate 104. In the illustrated embodiment, a first surface 306 of the glass plate 300 includes a diffusion filter 308. The diffusion filter 308 may be etched on the first surface 306 such that light incident at any particular angle is scattered into multiple angles as it is transmitted through the glass plate 300. Based on the desired optical characteristics of the transmitted light, the etched pattern may include random patterns of holes, lines, and other shapes. A second surface 310 of the glass plate 300 may include another filter, such as an IR filter 312. In the illustrated embodiment, the IR filter 312 may include a coating on the second surface 310. In one embodiment, the coating may be sputtered onto the glass plate 300. In various embodiments, the glass wafer may be processed to produce the diffusion filter 308 and the IR filter 312 on opposing surfaces. Subsequently, after further processing in various examples, the glass wafer can be diced into individual glass plates in the glass plate 300, and each such glass plate 300 can be attached to a semiconductor die with a light sensor, such as semiconductor die 114. In some other examples, the relative positions of the light filters can be reversed, such that the IR filter 312 is located on the first surface 306 and the diffusion filter 308 is located on the second surface 310.

[0062] In some applications, light incident on semiconductor die 114 may need to be at an unspecified angle within the IR spectrum of the light. This can lead to situations where the photosensor in semiconductor die 114 is prone to error if the incident light is at a specific angle or if the light intensity varies significantly across the surface of semiconductor die 114. In some such applications, a glass plate 300 with optical filters, as described herein, may be suitably used. In some applications, the choice of placing the IR filter 312 on the first surface 306 or the second surface 310 may depend on the material, type, or effectiveness of the IR filter 312 relative to the angle of the incident light. For example, some IR filters may be more effective if the incident light is diffused; in such cases, the IR filter 312 may be located on the second surface 310 such that light reaching the IR filter 312 has already been diffused by the diffusion filter 308 on the first surface 306.

[0063] Figure 4This is a simplified side view of the glass plate 400 used in the optical filter package 402 of the optical sensor system 404. In various embodiments, the glass plate 400 is generally similar to the glass plate 104. In the illustrated embodiment, the first surface 406 of the glass plate 400 includes a diffusion filter 408. The diffusion filter 408 may comprise droplets or other shapes of opaque or translucent material deposited on the first surface 406, such that light incident at any particular angle is scattered into multiple angles as it is transmitted through the glass plate 400. In some embodiments, the droplets may be in any random pattern; in other embodiments, the droplets may be in a regular array, deposited via screen printing or other such additive manufacturing processes. The pattern and shape of the deposited material may be based on the desired optical properties of the transmitted light. The second surface 410 of the glass plate 400 may include another filter, such as an IR filter 412. The IR filter 412 may be generally similar to the IR filter 312. In various embodiments, the glass wafer can be processed to create a diffusion filter 408 and an IR filter 412 on opposing surfaces. The glass wafer can then be diced into individual glass plates in glass plates 400, and each such glass plate 400 can be attached to a semiconductor die having a light sensor, such as semiconductor die 114. In some other embodiments, the relative positions of the light filters can be reversed such that the IR filter 412 is located on the first surface 406 and the diffusion filter 408 is located on the second surface 410.

[0064] Figure 5This is a simplified side view of the glass plate 500 used in the optical filter package 502 of the optical sensor system 504. In various embodiments, the glass plate 500 is generally similar to the glass plate 104. In the illustrated embodiment, the first surface 506 of the glass plate 500 includes a diffusion filter 508. The diffusion filter 508 may include a thin film containing a suspension of opaque or translucent material deposited on the first surface 506 such that light incident at any particular angle is scattered into multiple angles as it is transmitted through the glass plate 500. The suspended solid within the thin film may be of any suitable size and shape and may be in a random pattern. In some embodiments, such a diffusion film may be coated onto the first surface 506 using any suitable method, depending on the desired optical characteristics of the transmitted light, such as spin coating, UV curing, and / or annealing processes. The second surface 510 of the glass plate 500 may include another filter, such as an IR filter 512. The IR filter 512 may be generally similar to the IR filter 312. In various embodiments, the glass wafer can be processed to create a diffusion filter 508 and an IR filter 512 on opposing surfaces. The glass wafer can then be diced into individual glass plates in glass plates 500, and each such glass plate 500 can be attached to a semiconductor die having a light sensor, such as semiconductor die 114. In some other embodiments, the relative positions of the light filters can be reversed, such that the IR filter 512 is located on the first surface 506 and the diffusion filter 508 is located on the second surface 510.

[0065] Figures 6A to 6C A simplified view of an example glass plate 600 used in the optical filter package 602 of the optical sensor system 604. In various embodiments, glass plate 600 is generally similar to glass plate 104. Figures 6A to 6B In the first example shown, the first surface 606 of the glass plate 600 includes a microporous filter 608 comprising blind micropores with a diameter of less than 100 micrometers. In some examples, all micropores may have approximately the same diameter; in other examples, some micropores may have a different diameter than the others, depending on the desired angle of light to be transmitted through different regions of the glass plate 600. In some examples, the micropores may be at an angle relative to the first surface 606. The angle value may be selected according to a specific end-use application. For example, in an optical filter package 602, the micropores may be oriented at a 45° angle relative to the first surface 606, such that the incident angle has maximum intensity.

[0066] exist Figure 6A Cross-sectional view and Figure 6B In the example shown in the perspective view, microholes (e.g., microholes created using laser drilling, etching, or other methods) are drilled into the first surface 606. Figure 6CIn another example shown in the cross-sectional view, the micropores are included in a thin film coated on the first surface 606. The micropores facilitate precise control over the amount and angle of light transmitted through the glass plate 600. The second surface 610 of the glass plate 600 may include another filter, such as an IR filter 612. The IR filter 612 may be substantially similar to IR filter 312. In various examples, the glass wafer may be processed to create the microporous filter 608 and the IR filter 612 on opposing surfaces. Subsequently, the glass wafer may be cut into individual glass plates in the glass plate 600, and each such glass plate 600 may be attached to a semiconductor die with a light sensor, such as semiconductor die 114. In some other examples, the relative positions of the light filters may be reversed, such that the IR filter 612 is located on the first surface 606 and the microporous filter 608 is located on the second surface 610.

[0067] In some applications, light incident on semiconductor die 114 may need to be at a specified angle within the IR spectrum of the light. This can be a situation where a photosensor in semiconductor die 114 can detect an object at a specific angle or orientation. In some such applications, a glass plate 600 with optical filters, as described herein, may be suitably used. In some applications, the choice of placing the microporous filter 608 on the first surface 606 or the second surface 610 may depend on the desired optical properties of the effectiveness of the light transmitted through the glass plate 600 relative to the filter combination. For example, in some cases, placing the IR filter 612 on the first surface 606 may be more effective, where the effectiveness of the IR filter 612 is independent of the incident light angle.

[0068] Figure 7 This is a simplified side view of the glass plate 700 used in the optical filter package 702 of the optical sensor system 704. In various embodiments, the glass plate 700 is generally similar to the glass plate 104. In the illustrated embodiment, the first surface 706 of the glass plate 700 includes a diffusion filter 708. The diffusion filter 708 may include a reference... Figures 3 to 5 Any one of the structures shown and described. Figure 7 In the specific example shown, diffusion filter 708 is substantially similar to diffusion filter 308. The second surface 710 of glass plate 700 may include another filter, such as a microporous filter 712. The microporous filter 712 may be related to the reference filter. Figures 6A to 6C The microporous filter 608 shown and described is generally similar. In various embodiments, the glass wafer can be processed to produce the diffusion filter 708 and the microporous filter 712 on opposing surfaces. Subsequently, the glass wafer can be cut into individual glass plates in the glass plates 700, and each such glass plate 700 can be attached to a semiconductor die having a light sensor, such as semiconductor die 114.

[0069] Figure 8 This is a simplified side view of the glass plate 800 used in the optical filter package 802 of the optical sensor system 804. In various embodiments, the glass plate 800 is generally similar to the glass plate 104. In the illustrated embodiment, the first surface 806 of the glass plate 800 includes a microporous filter 808. The microporous filter 808 can be compared with a reference... Figures 6A to 6C The microporous filter 608 shown and described is generally similar. The second surface 810 of the glass plate 800 may include another filter, such as a diffusion filter 812. The diffusion filter 812 may include a reference... Figures 3 to 5 Any one of the structures shown and described. Figure 8 In the specific example shown, diffusion filter 812 is substantially similar to diffusion filter 308. In various examples, the glass wafer can be processed to create microporous filter 808 and diffusion filter 812 on opposing surfaces. The glass wafer can then be diced into individual glass plates in glass plates 800, and each such glass plate 800 can be attached to a semiconductor die having a light sensor, such as semiconductor die 114.

[0070] Figure 9 This is a simplified plan view of a glass plate 900 used in the optical filter package 902 of a light sensor system 904. The glass plate 900 may include multiple regions 906 to 914, each region having different types of optical filters on a first surface 916 and a second surface 918. In some instances, each of the multiple regions 906 to 914 may have a different filter combination on an opposite surface compared to the other regions. In one example, region 906 may include an IR filter located on the first surface 916 and another IR filter located on the second surface 918; region 908 may include a diffusion filter located on the first surface 916 and an IR filter located on the second surface 918, for example, similar to... Figures 3 to 5 The structure shown in any of the figures; region 910 may include a microporous filter located on the first surface 916 and an IR filter located on the second surface 918, for example, similar to Figures 6A to 6C The structure shown in any of the figures; region 912 may include a diffusion filter located on the first surface 916 and a microporous filter located on the second surface 918, for example, similar to Figure 7 The structure shown; and region 914 may include a microporous filter located on the first surface 916 and a diffusion filter located on the second surface 918, for example, similar to Figure 8 The structure shown is shown.

[0071] In the accompanying drawings, regions 906 to 914 are shown as continuous, with the edge of each region contacting the edge of an adjacent region. In other instances, regions 906 to 914 may be discontinuous; for example, the regions may be separated by other regions on the first surface 916 and / or the second surface 918 that do not have filters. Furthermore, in the figures, regions 906 to 914 are shown as regular rectangles; this is merely for illustration and not intended as a limitation. Depending on the end application, regions 906 to 914 can be of any suitable shape and different sizes. Additionally, within the range of various examples, any number of different regions may be provided in the glass plate 900. In some such examples, some regions may be similar to each other in configuration (e.g., structure), shape, and / or size. In some other such examples, each region may differ from all other regions in configuration, shape, and / or size.

[0072] Figure 10 A simplified plan view of some components of the optical filter package 1000 for the optical sensor system 1002. Multiple glass plates 1004 to 1012 are coupled to a third surface 1014 of a semiconductor die 1016. In various embodiments, planes along the surfaces of the multiple glass plates 1004 to 1012 are coplanar and parallel to the surface of the semiconductor die 1016. The semiconductor die 1016 may be substantially similar to semiconductor die 114 and may also include a light sensor, such as light sensor 115. Each glass plate 1004 to 1012 may include a corresponding filter combination on a respective first and second surface. For example, glass plate 1004 may include an IR filter on a first surface 1018 and another IR filter on a second surface 1020; glass plate 1006 may include a diffusion filter on a first surface 1022 and an IR filter on a second surface 1024, for example, similar to... Figures 3 to 5 The structure shown in any of the figures; the glass plate 1008 may include a microporous filter located on the first surface 1026 and an IR filter located on the second surface 1028, for example, similar to Figures 6A to 6C The structure shown in any of the figures; the glass plate 1010 may include a diffusion filter located on the first surface 1030 and a microporous filter located on the second surface 1032, for example, similar to Figure 7 The structure shown; and the glass plate 1012 may include a microporous filter located on the first surface 1034 and a diffusion filter located on the second surface 1036, for example, similar to Figure 8 The structure shown is shown.

[0073] In the accompanying drawings, glass plates 1004 to 1012 are shown as regular rectangles; this is merely for illustration and is not intended to be limiting. Glass plates 1004 to 1012 can be any suitable shape (e.g., hexagonal, triangular, irregular shape, etc.) and of varying sizes, depending on the end application. In various embodiments, the spacing between individual glass plates 1004 and 1012 can be determined by handling accuracy and other manufacturing issues beyond the scope of this disclosure. Furthermore, within the scope of various examples, any number of different glass plates can be disposed on the third surface 1014 of the semiconductor die 1016. In some such examples, some glass plates may be similar to each other in configuration (e.g., structure), shape, and / or size. In some other such examples, each glass plate may differ from all the other glass plates in configuration, shape, and / or size.

[0074] Figure 11 This is a simplified cross-sectional view of an example optical filter package 1100 used in the optical sensor system 1102. The optical filter package 1100 includes a glass plate 1104 having a first surface 1106 and a second surface 1108 opposite to the first surface 1106. The first surface 1106 has a first filter 1110, and the second surface 1108 has a second filter 1112 different from the first filter 1110. The optical package 1100 further includes a semiconductor die 1114 having a third surface 1116 and a fourth surface 1118 opposite to the third surface 1116. The semiconductor die 1114 may be substantially similar to the semiconductor die 1115 and may also include a light sensor, such as a light sensor 115. At least a portion of the third surface 1116 has a color filter 1120. An optically transparent adhesive 1122 contacts the second surface 1108 of the glass plate 1104 and the third surface 1116 of the semiconductor die 1114. An optically opaque molding compound 1124 circumferentially surrounds the glass plate 1104 and the semiconductor die 1114, exposing the first filter 1110. A substrate 1126 includes a first region 1128 adjacent to the fourth surface 1118 of the semiconductor die 1114. The substrate 1126 further includes a second region 1130 electrically coupled to the semiconductor die 1114 via a wire bond 1132. An adhesive 1134 contacts the substrate 1126 and the fourth surface 1118 of the semiconductor die 1114. In some embodiments, such as the one shown in the figure, the first occupied area 1136 of the semiconductor die 1114 may be approximately the same as the second occupied area 1138 of the glass plate 1104. Additionally, the outer peripheral edge 1140 of the optically transparent adhesive 1122 may be substantially flush with the outer peripheral edge 1142 of the glass plate 1104 (for example, the area occupied by the optically transparent adhesive 1122 may be approximately equal to the area occupied by the glass plate 104 1138 and the area occupied by the semiconductor die 1114 1136).

[0075] The wire bond 1132 may be partially embedded in the optically clear adhesive 1122. The thickness 1144 of the optically clear adhesive 1122 may be selected to be greater than the height 1146 of the wire bond 1132 above the third surface 1116 of the semiconductor die 1114. Furthermore, the material of the optically clear adhesive 1122 may be selected to have liquid properties and undergo stage B curing when applied to the glass plate 1104. When the glass plate 1104 is placed above the semiconductor die 1114 and then heated, the material further liquefies and disperses above and around the wire bond 1132 above the third surface 1116. Upon complete curing, the material solidifies, encapsulating the end of the wire bond 1132 beneath the glass plate 1104.

[0076] In the illustrated example, the optical filter package 1100 is a QFN or DFN package, exposing regions 1128 and 1130 of the substrate 1126 opposite to the first surface 1106 of the glass plate 1104. Various other package formats may be used without departing from the scope of the examples described herein. The substrate 1126 can be mounted to a PCB such that regions 1128 and 1130 of the substrate 1126 opposite to the first surface 1106 of the glass plate 1104 are electrically and / or thermally bonded to the PCB. During operation, light can be incident on the first surface 1106 and appropriately detected by circuitry in the semiconductor die 1114.

[0077] Figure 12This is a simplified cross-sectional view of an example optical filter package 1200 used in the optical sensor system 1202. The optical filter package 1200 includes a glass plate 1204 having a first surface 1206 and a second surface 1208 opposite to the first surface 1206. The first surface 1206 has a first filter 1210, and the second surface 1208 has a second filter 1212 different from the first filter 1210. The optical package 1200 further includes a semiconductor die 1214 having a third surface 1216 and a fourth surface 1218 opposite to the third surface 1216. The semiconductor die 1214 may be substantially similar to semiconductor die 114 and may also include a light sensor, such as a light sensor 115. At least a portion of the third surface 1216 has a color filter 1220. An optically transparent adhesive 1222 contacts the second surface 1208 of the glass plate 1204 and the third surface 1216 of the semiconductor die 1214. An optically opaque molding compound 1224 circumferentially surrounds the glass plate 1204 and the semiconductor die 1214. A substrate 1226 includes a first region 1228 adjacent to a fourth surface 1218 of the semiconductor die 1214. The substrate 1226 further includes a second region 1230 electrically coupled to the semiconductor die 1214 via a wire bond 1232. An adhesive 1234 contacts the substrate 1226 and the fourth surface 1218 of the semiconductor die 1214.

[0078] In various instances, multiple additional glass plates can be layered and coupled to glass plate 1204, with different combinations of optical filters. For example, glass plate 1236 can be coupled to a portion of glass plate 1204 via optically clear adhesive 1238. A first surface 1240 of glass plate 1236 has a first filter 1242, and a second surface 1244 has a second filter 1246 different from the first filter 1242. Optically clear adhesive 1238 can be located between the first surface 1206 of glass plate 1204 and the second surface 1244 of glass plate 1236. Similarly, another glass plate 1248 can be coupled to another portion of glass plate 1204 via optically clear adhesive 1250. A first surface 1252 of glass plate 1248 has a first filter 1254, and a second surface 1256 has a second filter 1258 different from the first filter 1254. Optically transparent adhesive 1250 may be located between the first surface 1206 of glass plate 1204 and the second surface 1256 of glass plate 1248.

[0079] Optically opaque molding compound 1224 circumferentially surrounds glass plates 1236 and 1248, exposing the first filters 1242 and 1254 of the respective glass plates 1236 and 1248. In some embodiments, a gap 1260 may exist between glass plates 1236 and 1248. In other embodiments, the gap 1260 may be negligible or absent, allowing adjacent outer peripheral sides of glass plates 1236 and 1248 to contact each other. The presence of the gap 1260 may depend on handling tolerances and other manufacturing issues beyond the scope of the embodiments. In many cases, based on the manufacturing process, the outer peripheral edges of optically transparent adhesives 1222, 1238, and 1250 may be flush with the edges of the respective glass plates 1204, 1236, and 1248. For example, in some manufacturing processes, an optically clear adhesive can be applied as a thin film onto a glass wafer; the glass wafer is then diced into individual glass plates, suitably mounted onto semiconductor die 1214 and onto other glass plates as described herein, and subjected to a curing process to cure the optically clear adhesive. In some instances, glass plates 1204, 1236, and 1248 may be derived from different glass wafers.

[0080] In some instances, a single glass plate may be mounted on glass plate 1204 instead of multiple glass plates 1236 and 1248. In some such instances, the area occupied by the additional glass plate may be the same as that occupied by glass plate 1204. In other such instances, the area occupied by the additional glass plate may be smaller than that occupied by glass plate 1204. The choice between multiple glass plates and a single glass plate, and the choice of different types of filters for each glass plate, may be based on the optical requirements of the light incident on a suitable photosensor in semiconductor die 1214. For example, light incident on region 1262 of the third surface 1216 of semiconductor die 1214 may be expected to have a first set of optical properties (e.g., green wavelength, light incident on surface 1240 at a first angle, maximum predetermined intensity); light incident on region 1264 of the third surface 1216 of semiconductor die 1214 may be expected to have a second set of optical properties (e.g., red wavelength, light incident on surface 1252 at a second angle, minimum predetermined intensity); and so on. These optical requirements may be based on the functionality of the underlying optical circuitry in the semiconductor die 1214 and extend beyond the scope of this disclosure. Therefore, the combination of filters 1242, 1246, 1210, 1212, and 1220 above region 1262 may differ from the combination of other filters 1254, 1258, 1210, 1212, and 1220 above region 1264. In some cases, one or more filters may not be present in the stack. For example, the filter stack above region 1262 may not have a color filter 1220, and the filter stack may contain only one or more IR filters, while another filter stack above region 1264 may include a color filter and one or more diffusion filters and microporous filters. Therefore, various filter combinations can be placed at the packaging level on the semiconductor die 1214 based on specific needs.

[0081] In the illustrated example, the optical filter package 1200 is a QFN or DFN package format, exposing regions 1228 and 1230 of the substrate 1226. Various other package formats may also be used without departing from the scope of the examples described herein. The substrate 1226 can be mounted to a PCB such that regions 1228 and 1230 of the substrate 1226 are electrically and / or thermally bonded to the PCB. During operation, light incident on the optical sensor system 1202 can be transmitted through various filters 1242, 1254, 1246, 1258, 1210, 1212, and 1220 for appropriate detection by circuitry in the semiconductor die 1214.

[0082] Figure 13This is a simplified cross-sectional view of an example optical filter package 1300 used in the optical sensor system 1302. The optical filter package 1300 includes a glass plate 1304 having a first surface 1306 and a second surface 1308 opposite to the first surface 1306. The first surface 1306 has a first filter 1310, and the second surface 1308 has a second filter 1312 different from the first filter 1310. The optical package 1300 further includes a semiconductor die 1314 having a third surface 1316 and a fourth surface 1318 opposite to the third surface 1316. The semiconductor die 1314 may be substantially similar to semiconductor die 114 and may also include a light sensor, such as a light sensor 115. At least a portion of the third surface 1316 has a color filter 1320. An optically transparent adhesive 1322 contacts a second surface 1308 of a glass plate 1304 and a third surface 1316 of a semiconductor die 1314. An optically opaque molding compound 1324 circumferentially surrounds the glass plate 1304 and the semiconductor die 1314. A substrate 1326 includes a first region 1328 adjacent to a fourth surface 1318 of the semiconductor die 1314. The substrate 1326 further includes a second region 1330 electrically coupled to the semiconductor die 1314 via a wire bond 1332. In the illustrated example, the optical filter package 1300 is configured as a lead frame. In such examples, the first region 1328 may include die pads, and the second region 1330 may include wire fingers. An adhesive 1334 contacts the substrate 1326 and the fourth surface 1318 of the semiconductor die 1314.

[0083] Figure 14This is a simplified cross-sectional view of an example optical filter package 1400 used in an optical sensor system 1402. The optical filter package 1400 includes a glass plate 1404 having a first surface 1406 and a second surface 1408 opposite to the first surface 1406. The first surface 1406 has a first filter 1410, and the second surface 1408 has a second filter 1412 different from the first filter 1410. The optical package 1400 further includes a semiconductor die 1414 having a third surface 1416 and a fourth surface 1418 opposite to the third surface 1416. The semiconductor die 1414 may be substantially similar to semiconductor die 114 and may also include a light sensor, such as a light sensor 115. At least a portion of the third surface 1416 has a color filter 1420. Optically transparent adhesive 1422 contacts a second surface 1408 of glass plate 1404 and a third surface 1416 of semiconductor die 1414. Optically opaque molding compound 1424 circumferentially surrounds glass plate 1404 and semiconductor die 1414. Substrate 1426 includes a first region 1428 adjacent to a fourth surface 1418 of semiconductor die 1414. Substrate 1426 further includes a second region 1430 electrically coupled to semiconductor die 1414 via wire bonding 1432. In the illustrated example, optical filter package 1400 is configured as a ball grid array package, wherein solder balls 1434 are located on the surface of substrate 1426 opposite to semiconductor die 1414. In such examples, the second region 1430 may include bonding pads on substrate 1426. Substrate 1426 may include a stack of organic dielectrics and embedded electrical conductors (e.g., conductive vias between metal layers and organic dielectric layers). The adhesive 1436 contacts the fourth surface 1418 of the substrate 1426 and the semiconductor die 1414.

[0084] Although this disclosure has been described in detail with reference to specific arrangements and configurations, these example arrangements and configurations may be significantly modified without departing from the scope of this disclosure. For example, although this disclosure has been described with reference to optically opaque molding compounds, the same arrangements and configurations may be applied to other types of molding compounds, such as transparent molding compounds. Furthermore, although specific element diagrams illustrating optical filter packages and light sensors have been referenced to facilitate optical processing functionality, these elements and operations may be used in place of any other suitable architecture for non-optical processing (e.g., electrical signal processing).

[0085] Figure 15This is a simplified flowchart illustrating an example operation 1500 associated with manufacturing an optical filter package (e.g., optical filter package 100). At 1502, an optically clear adhesive 122 is applied to a glass wafer including a first filter 110 on a first surface 106 and a second filter 112 on a second surface 108. In some instances, the optically clear adhesive 122 may be in the form of a film; in other instances, the optically clear adhesive 122 may be in the form of a liquid, which is uniformly applied and dries without curing. At 1504, the glass wafer is diced into individual glass plates in glass plate 104. The size of the die may be based on the size of the semiconductor die 114 to which it is to be attached. In some instances, the area occupied by the glass plate 104 is smaller than the area occupied by the semiconductor die 114.

[0086] At 1506, the semiconductor die 114 can be attached to the substrate 126 using adhesive 134. At 1508, a color filter 120 can be applied to the exposed surface (i.e., the third surface 116) of the semiconductor die 114. In some examples, multiple semiconductor dies in the semiconductor dies 114 on one or more wafers can be operated on simultaneously at the wafer level. Afterward, individual semiconductor dies in the semiconductor die 114 can be diced (e.g., cut and separated from the wafer). In some examples, the operation at 1508 can be performed prior to the operation at 1506. In some examples, the operation at 1508 can be performed prior to the operation at 1502. At 1510, the glass plate 104 can be placed on the top surface of the die assembly, i.e., the third surface 116 of the semiconductor die 114, using an optically clear adhesive 122 between the glass plate 104 and the third surface 116. For example, as in... Figure 12In the illustrated arrangement, the operation at 1510 can be repeated to attach an additional glass plate to the top of glass plate 104. After all glass plates have been placed as needed, at 1512, pressure can be applied to the topmost surface of the exposed glass plates, and the optically clear adhesive 122 can undergo a curing process (e.g., by heating, using ultraviolet light, drying, etc.). During this process, the optically clear adhesive 122 can be liquefied and flowed under pressure (or temperature) to conform to the morphology formed by the color filter 120 on the third surface 116 of the semiconductor die 114. For example, the optically clear adhesive 122 conforms to the topological changes of the surface on the semiconductor die 114. In some instances, the attachment of the glass plates can be performed one by one, rather than placing all the glass plates on top of each other and then applying pressure and heating to the topmost surface. Thus, after attaching one glass plate by curing the optically clear adhesive, the next glass plate is attached, and the adhesive is cured. The process can continue until all glass plates are attached as needed. In some instances where the topology of the third surface 116 of the semiconductor die 114 is within a predetermined range (e.g., the surface has a uniform topology, the color filter 120 has substantially the same thickness, etc.), at 1512, pressure may not be applied, and the optically transparent adhesive 122 may be directly subjected to the curing process.

[0087] After the optically transparent adhesive 122 has cured, at 1514, the semiconductor die 114 can be wire-bonded to the substrate 126. At step 1516, an optically opaque molding compound 124 can be applied along the outer periphery surrounding the semiconductor die 114 and the glass plate 104. In some examples, the optically opaque molding compound 124 is added via a thin-film assisted molding process. At 1518, the optically opaque molding compound 124 can be appropriately cured (e.g., by heating or ultraviolet energy).

[0088] although Figure 15 The illustrations depict various operations performed in a specific order, but this is merely illustrative, and the operations discussed herein may be reordered and / or repeated as needed. Furthermore, additional operations not illustrated may be performed without departing from the scope of this disclosure. Moreover, based on this disclosure, the descriptions herein regarding… Figure 15 The various operations described are modified to manufacture the optical filter package 100 as disclosed herein. For example, in order to form such... Figure 11 The structure shown allows for the wire bonding operation at operation 1514 to be performed before the glass plate 104 is placed on the top surface of the die assembly at operation 1510. In another example, in order to form as... Figure 1The structure shown, where the order of the wire bonding operation at 1514 relative to the operation at 1510 can be based on other constraints, such as the size of the wire bonding equipment to avoid contact with the glass plate 104, or the pick-and-place accuracy of the equipment that places the glass plate 104 on the top surface of the die assembly to prevent contact with the already in place wire bond, etc. Although various operations in Figure 15 The diagram shows the operation performed once, but it can be repeated multiple times as needed.

[0089] It is important to note that the operations described with reference to the foregoing figures only illustrate some of the possible scenarios in which the optical filter package 100 can be manufactured. Where appropriate, some of these operations may be deleted or removed, or these steps may be significantly modified or altered without departing from the scope of the concepts discussed. Furthermore, the timing of these operations can be significantly changed while still achieving the results taught in this disclosure. The aforementioned operational procedures have been provided for purposes of illustration and discussion.

[0090] The above description of the illustrated embodiments of this disclosure includes the content described in the abstract and is not intended to be exhaustive or to limit this disclosure to its precise form. Although specific embodiments and examples of this disclosure have been described herein for illustrative purposes, various equivalent modifications can be made within the scope of this disclosure, as will be recognized by those skilled in the art.

Claims

1. An optical filter package, comprising: A glass plate having a first surface and a second surface opposite to the first surface, wherein the first surface has a first filter and the second surface has a second filter different from the first filter; A semiconductor die comprising a photosensor and having a third surface and a fourth surface opposite the third surface, wherein at least a portion of the third surface has a third filter; and An optically transparent adhesive is used to contact the second surface of the glass plate and the third surface of the semiconductor die.

2. The optical filter package according to claim 1, wherein the first filter and the second filter are one of the following: a diffusion filter, a microporous filter, or an infrared filter.

3. The optical filter package according to claim 1, wherein in a plan view, the glass plate includes a plurality of different regions, each region having a different filter combination on the first surface and the second surface.

4. The optical filter package according to claim 1, further comprising a plurality of glass plates, each glass plate having a different filter combination on opposite surfaces parallel to the third surface.

5. The optical filter package of claim 4, wherein the planes along the surface of each glass plate are coplanar.

6. The optical filter package according to claim 4, wherein some of the plurality of glass plates are stacked on some other glass plates.

7. The optical filter package according to claim 1, wherein: The glass plate has a first occupied area. The semiconductor die has a second occupied area, and The first occupied area is smaller than the second occupied area.

8. The optical filter package of claim 1, further comprising a plurality of color filters located on the third surface of the semiconductor die, wherein in the plurality of color filters: At least two color filters are used to filter different colors. At least one color filter has a first thickness, and At least one other color filter has a second thickness that is different from the thickness of the first layer.

9. The optical filter package according to claim 1, wherein the third filter is located between the photosensor and the optically transparent adhesive.

10. An optical filter package, comprising: A glass plate having a first surface and a second surface opposite to the first surface, wherein the first surface has a first filter and the second surface has a second filter; A semiconductor die comprising a photosensor and having a third surface and a fourth surface opposite to the third surface, wherein at least a portion of the third surface has a third filter; An optically transparent adhesive is used to contact the second surface of the glass plate and the third surface of the semiconductor die. An optically opaque molding compound circumferentially surrounds the glass plate and the semiconductor die, such that the first surface of the glass plate is exposed; A substrate comprising a first region adjacent to the fourth surface of the semiconductor die and a second region electrically coupled to the semiconductor die; and An adhesive that mechanically couples the substrate to the fourth surface of the semiconductor die.

11. The optical filter package of claim 10, wherein the first filter or the second filter comprises a material deposited on the first surface or the second surface.

12. The optical filter package of claim 10, wherein the first filter or the second filter comprises a shape etched on the first surface or the second surface.

13. The optical filter package of claim 10, further comprising a plurality of glass plates, each glass plate having a different filter combination on opposite surfaces parallel to the third surface.

14. The optical filter package according to claim 10, wherein the optical filter package is a quad flat no-lead QFN package.

15. The optical filter package according to claim 10, wherein the substrate is a lead frame.

16. The optical filter package of claim 10, wherein the substrate comprises an organic dielectric material and an embedded electrical conductor.

17. A method for manufacturing an integrated filter package, comprising: An optically transparent adhesive film is attached to a glass wafer, the glass wafer comprising different filters on opposite surfaces; The glass wafer is cut into individual glass plates, each glass plate containing a portion of the optically transparent adhesive film; A glass plate is placed on the top surface of the assembly, which includes a semiconductor die containing a light sensor, wherein: The surface of the semiconductor wafer adjacent to the glass plate includes at least one other filter, and The portion of the optically transparent adhesive film is located between the glass plate and the surface of the semiconductor die; Pressure is applied to the exposed surface of the glass plate, and the portion of the optically transparent adhesive film is cured. The semiconductor die is electrically coupled to the substrate; An optically opaque molding compound is applied along the outer periphery of the semiconductor die and the glass plate; and The optically opaque molding compound is cured.

18. The method of claim 17, further comprising attaching the semiconductor die to the substrate with an adhesive.

19. The method of claim 17, wherein the optically opaque molding compound is applied by a thin-film assisted molding process.

20. The method of claim 17, further comprising: Multiple glass plates are placed on the semiconductor die, and each glass plate has a different combination of filters on opposite surfaces parallel to the surface of the semiconductor die. and Pressure is applied to all exposed surfaces of the plurality of glass plates, and the temperature is increased until each portion of the optically transparent adhesive film between the plurality of glass plates and the semiconductor die is cured.

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