IMAGE SENSOR PACKAGES AND RELATED METHODS
Implementations of image sensor packages may include a plurality of microlenses coupled over a color filter array (CFA), a low refractive index layer directly coupled to and over the plurality of microlenses, an adhesive directly coupled to and over the low refractive index layer, and an optically transmissive cover directly coupled to and over the adhesive. Implementations may include no gap present between the optically transmissive cover and the plurality of microlenses.
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This application is a continuation application of the earlier U.S. Utility Patent Application to Oswald Skeete entitled “Image Sensor Packages and Related Methods,” application Ser. No. 16/455,094, filed Jun. 27, 2019, now pending, the disclosure of which is hereby incorporated entirely herein by reference.
BACKGROUND 1. Technical FieldAspects of this document relate generally to image sensors and image sensor packages.
2. BackgroundImage sensors convey information related to an image by communicating signals in response to incident electromagnetic radiation. Image sensors are used in a variety of devices including smart phones, digital cameras, night vision devices, medical imagers, and many others. Various types of image sensors exist, such as CMOS image sensors (CIS) and charge coupled devices (CCDs).
SUMMARYImplementations of image sensor packages may include a plurality of microlenses coupled over a color-filter-array (CFA), a low refractive index layer directly coupled to and over the plurality of microlenses, an adhesive directly coupled to and over the low refractive index layer, and an optically transmissive cover directly coupled to and over the adhesive. Implementations may include no gap present between the optically transmissive cover and the plurality of microlenses.
Implementations of image sensor packages may include one, all, or any of the following:
The low refractive index layer may include one of an acrylic resin, polymer resins, an inorganic filler, inorganic fillers, an aerogel material, or any combination thereof.
The low refractive index layer may include a refractive index of 1.2.
The low refractive index layer may include a thickness less than 5 micrometers.
The adhesive layer may be directly coupled to an entire surface of the optically transmissive cover.
Implementations of image sensor packages may include a first side of a substrate coupled to a digital signal processor through a plurality of electrical contacts and an image sensor coupled to the first side of the substrate. Implementations of image sensor packages may also include an underfill layer coupled over the substrate, a plurality of microlenses coupled over the image sensor, and an optically transmissive cover coupled over the plurality of microlenses. Implementations may include no gap present between the optically transmissive cover and the plurality of microlenses
Implementations of image sensor packages may include one, all, or any of the following:
Implementations may include a mold compound directly coupled to the first side of the substrate and to two or more sides of the optically transmissive cover, the image sensor, the digital signal processor, and the underfill layer.
Implementations may include a mold compound directly coupled over a first surface of the optically transmissive cover opposite a second surface of the optically transmissive cover facing the plurality of microlenses.
The image sensor package may include an adhesive and a low refractive index layer coupled between the optically transmissive cover and the plurality of microlenses.
The image sensor may be stacked over the digital signal processor and the digital signal processor may include a plurality of through silicon vias therein.
The low refractive index layer may include one of an acrylic resin, polymer resins, an inorganic filler, inorganic fillers, an aerogel material, or any combination thereof.
A perimeter of the optically transmissive cover may be smaller than a perimeter of the substrate.
The low refractive index layer may include a refractive index of 1.2.
Implementations of a method of forming an image sensor package may include bonding an image sensor wafer to a digital signal processor wafer, backgrinding the digital signal processor wafer to a predetermined thickness, and coupling an optically transmissive substrate over the image sensor wafer. Implementations may include no gap present between the optically transmissive substrate and the image sensor wafer. Implementations of a method of forming an image sensor package may also include exposing a plurality of electrical pads through an oxide layer using the optically transmissive substrate as a support, coupling a plurality of electrical contacts to the plurality of electrical pads, and singulating the optically transmissive substrate, the image sensor wafer, and the digital signal processor wafer into a plurality of optically transmissive covers, image sensor die, and digital signal processor die.
Implementations of methods of forming image sensor packages may include one, all, or any of the following:
Implementations may include coupling a mold compound to two or more sidewalls of each image sensor die, digital signal processor die, and optically transmissive cover.
Implementations may include forming a plurality of through-silicon-vias in the digital signal processor wafer.
Implementations may include applying an underfill compound between each of the plurality of electrical contacts.
Implementations may include applying an optically transmissive adhesive along an entire surface of the optically transmissive substrate.
Implementations may include applying a low refractive index layer over the image sensor wafer.
The low refractive index layer may include a refractive index of 1.2.
The foregoing and other aspects, features, and advantages will be apparent to those artisans of ordinary skill in the art from the DESCRIPTION and DRAWINGS, and from the CLAIMS.
Implementations will hereinafter be described in conjunction with the appended drawings, where like designations denote like elements, and:
This disclosure, its aspects and implementations, are not limited to the specific components, assembly procedures or method elements disclosed herein. Many additional components, assembly procedures and/or method elements known in the art consistent with the intended image sensor packages will become apparent for use with particular implementations from this disclosure. Accordingly, for example, although particular implementations are disclosed, such implementations and implementing components may comprise any shape, size, style, type, model, version, measurement, concentration, material, quantity, method element, step, and/or the like as is known in the art for such image sensor packages, and implementing components and methods, consistent with the intended operation and methods.
Referring to
In various implementations, the image sensor package 2 includes a low refractive index layer 8 coupled to and over the plurality of microlenses 6. In particular implementations, and as illustrated, the low refractive index layer 8 is directly coupled to the plurality of microlenses. As illustrated, the low refractive index layer 8 may form a level layer above the CFA and microlenses 6. In other implementations, additional layers may separate the plurality of microlenses 6 from the low refractive index layer 8. The low refractive index layer 8 is optically transmissive. In various implementations, the low refractive index layer 8 has a refractive index of 1.2. In other implementations, the low refractive index layer 8 may have a refractive index more than or less than 1.2.
In various implementations the low refractive index layer 8 may be less than 5 micrometers (μm) thick. In particular implementations, the low refractive index layer 8 may be 1.2 μm thick. In other implementations, the thickness of the low refractive index layer 8 may be more than 5 μm thick. In particular implementations the low refractive index layer 8 includes one or more polymeric layers. The one or more polymeric layers may contain, by non-limiting example, one or more polymer resins, one or more acrylic resins, an inorganic filler, inorganic fillers, an aerogel material, aerogel materials, any combination thereof, or any other molecular materials that decrease a density of the low refractive index layer(s). In a particular implementation, the low refractive index layer may include a material marketed under the tradename of LAL-2020™ by Tokyo Ohka Kogyo Co., LTD of Kawasaki, Japan. In other implementations, the low refractive index layer 8 may include other materials.
In various implementations, the image sensor package 2 includes an adhesive 10 coupled to and over the low refractive index layer 8. In particular implementations, the adhesive 10 is directly coupled to the low refractive index layer 8, and may be directly coupled to an entire surface of the optically transmissive cover. In other implementations, additional layers may separate the low refractive index layer 8 from the adhesive 10. While
In various implementations, the adhesive 10 may include a refractive index of 1.5. In other implementations, the adhesive 10 may include a refractive index greater than or less than 1.5.
Still referring to
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In various implementations, and as illustrated by
In various implementations, the method of forming the gapless portion of the image sensor package may include applying a low refractive index layer, including any type of low refractive index layer disclosed herein, over the plurality of microlenses and an image sensor layer. The method may also include applying the adhesive, including any adhesive disclosed herein, to an optically transmissive substrate. In various implementations, the adhesive may be spin coated onto the optically transmissive substrate. The adhesive may cover an entire surface of the optically transmissive substrate. In various implementations, the method includes bonding the adhesive to the low refractive index layer. In particular implementations, the adhesive may be directly bonded to the low refractive index layer. In various implementations, the method may include curing the adhesive through an ultra violet (UV) cure or another curing process. The method may also include singulating the optically transmissive substrate, the adhesive, the low refractive index layer, and the image sensor wafer into a plurality of image sensor packages.
In implementations including a mask layer, the method may include applying the mask layer and patterning the mask layer either before or after the low refractive index layer is applied.
Referring to
As illustrated, the plurality of microlenses 18 are coupled over a CFA 24. The CFA 24 is coupled over the image sensor 26. In various implementations, the image sensor 26 is 5 μm thick. In other implementations, the image sensor may be more or less than 5 μm thick. In various implementations, the image sensor 26 may be a backside image sensor (BSI) and/or any other type of image sensor disclosed herein. As illustrated by
The image sensor package 14 may include a substrate 36 having a first side 38 and a second side 40 opposing the first side. As illustrated, a perimeter of the substrate 36 may be greater than a perimeter of the optically transmissive cover 16. In various implementations, the substrate 36 may include a power plane 44 and a ground plane 46 which may improve electrical performance. The first side 38 of the substrate may be coupled to the digital signal processor 28 through a plurality of electrical contacts 42. The plurality of electrical contacts 42 may be, by non-limiting example, bumps, studs, pins, pillars, balls, paste, or any other type of electrical contact. Similarly, the plurality of electrical contacts 42 may include copper, any other metal or alloy thereof, a solder, or any other conductive material. The plurality of electrical contacts 42 may be coupled to the one or more TSVs 30. In various implementations, the electrical contacts 42 improve the thermal performance of the image sensor package 14. As illustrated by
In various implementations the image sensor package 14 includes an underfill layer 50 coupled between the substrate 36 and the digital signal processor 28. In various implementations, the underfill layer 50 may entirely fill the space between the substrate 36 and the oxide layer 34 and partially encapsulate the plurality of electrical contacts 42. The underfill may be used to assist in maintaining the reliability of the connections between the solder balls 48 and a circuit board to which the solder balls 48 are ultimately coupled. Still referring to
In various implementations the mold compound may include an epoxy molding compound, an acrylic molding compound, or any other molding compound capable of hardening and providing physical support, light blocking, and/or humidity protection to a semiconductor device.
While
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In various implementations, the method of forming an image sensor package may include coupling an adhesive 76 between the optically transmissive substrate 74 and the low refractive index layer 72. The adhesive may be any type of adhesive disclosed herein, and may be applied in any thickness disclosed herein. In particular implementations, the adhesive 76 may be optically transmissive. In various implementations, the adhesive 76 may be spin coated onto the optically transmissive substrate 74 prior to coupling the optically transmissive substrate over the image sensor wafer 54. The adhesive 76 may cover an entire surface of the optically transmissive substrate 74. In various implementations, the method includes bonding the adhesive 76 to the low refractive index layer 72. In particular implementations, the adhesive 76 may be directly bonded to the low refractive index layer 72. In various implementations, the method may include curing the adhesive 76 through an ultra violet (UV) cure or another curing process. As is illustrated by
Referring to
Another implementation of forming a substrate and wafers similar to those illustrated by
Referring to
In various implementations, the method of forming an image sensor package may include coupling an adhesive 138 between the optically transmissive substrate 136 and the low refractive index layer 134. The adhesive may be any type of adhesive disclosed herein, and may be applied in any thickness disclosed herein. In particular implementations, the adhesive 138 may be optically transmissive. In various implementations, the adhesive 138 may be spin coated onto the optically transmissive substrate 136 prior to coupling the optically transmissive substrate over the image sensor wafer 126. The adhesive 138 may cover an entire surface of the optically transmissive substrate 136. In various implementations, the method includes bonding the adhesive 138 to the low refractive index layer 134. In particular implementations, the adhesive 138 may be directly bonded to the low refractive index layer 134. In various implementations, the method may include curing the adhesive 138 through an ultra violet (UV) cure or another curing process. As is illustrated by
In various implementations, referring to
Referring to
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In various implementations, the method of forming the image sensor package includes forming a plurality of electrical contacts 124 to the second side of the substrate opposing the first side 122 of the substrate 96. The electrical contacts may be any type of electrical contact disclosed herein. The method of forming an image sensor package also includes singulating the mold compound 120 and the substrate 96 into a plurality of image sensor packages 116. The various methods disclosed herein do not include die-level keep out zones.
While the implementations of the methods of forming an image sensor package disclosed herein primarily refer to methods of forming image sensor packages having an image sensor stacked over a digital signal processor, in other implementations, methods of forming an image sensor package may include forming a package not having an image sensor stacked over a digital signal processor. In such implementations, the image sensor may be arranged side by side with the digital signal processor over the substrate (or included together in the same die). In such implementations, the method of forming the image sensor package may include coupling an optically transmissive substrate over and to a wafer including both image sensors and digital signal processors. In various implementations, the method may include forming a plurality of TSVs in the wafer including image sensors and digital signal processors. In various implementations, the method may also include singulating the wafer including image sensors and digital signal processors into die including an image sensor and a digital signal processor. In such implementations each die may then be coupled over a substrate individually or simultaneously. In various implementations, an underfill layer and/or mold compound may be coupled over the substrate similar to any method disclosed herein and the substrate and/or the mold compound may be singulated into image sensor packages.
The various implementations of methods of forming image sensor packages disclosed herein include methods of forming image sensor packages where no gap is present between the optically transmissive cover of the package and the image sensor die. In the methods of forming the flip chips disclosed herein the flip chip is self-aligning when the solder reflows and then solidifies. This is because the use of the bumps helps the image sensor to stay in the desired location during the reflow process. Similarly, when forming the flip chip, the die position in each of the X and Y directions may be affected by less than 10 μm. Similarly, the die tilt may be affected by less than 0.1 degrees and the die rotation is affected by less than 0.2 degrees. The use of the gapless image sensor implementations in this document permits the use of pillar/ball electrical connectors, which allows for more precise die placement and avoidance of die tilt when compared with wirebonded image sensor die processing in a physically smaller package size.
In places where the description above refers to particular implementations of image sensor packages and implementing components, sub-components, methods and sub-methods, it should be readily apparent that a number of modifications may be made without departing from the spirit thereof and that these implementations, implementing components, sub-components, methods and sub-methods may be applied to other image sensor packages.
Claims
1. A sensor package comprising:
- a substrate including a sensor die, the sensor die configured to receive an incoming optical signal;
- one or more optically transmissive layers including an edge surface positioned at an edge of the sensor package; and
- a light blocking layer that contacts a first optically transmissive layer of the one or more optically transmissive layers and follows along a perimeter of the first optically transmissive layer;
- wherein the light blocking layer is positioned between the edge surface of the sensor package and a plurality of microlenses.
2. The sensor package of claim 1, further comprising a mold compound that couples the one or more optically transmissive layers and the sensor die.
3. The sensor package of claim 1, wherein the light blocking layer is coupled over a surface of the first optically transmissive layer.
4. The sensor package of claim 4, wherein the surface of the first optically transmissive layer is the surface of the first optically transmissive layer most proximal to the substrate.
5. The sensor package of claim 4, wherein the surface of the first optically transmissive layer is the surface of the first optically transmissive layer most distal to the substrate.
6. The sensor package of claim 1, wherein the light blocking layer is embedded in the first optically transmissive layer.
7. The sensor package of claim 1, further comprising a digital signal processor die coupled to the sensor die opposite the one or more optically transmissive layers.
8. The sensor package of claim 1, wherein the one or more optically transmissive layers include a transparent or translucent layer.
9. The sensor package of claim 1, wherein the one or more optically transmissive layers include a low refractive index layer.
10. The sensor package of claim 1, wherein the light blocking layer extends to an outer edge of the sensor package.
11. The sensor package of claim 1, further comprising:
- one or more metal structures on the substrate, wherein the light blocking layer is positioned between the one or more metal structures and the first optically transmissive layer.
12. The sensor package of claim 1, wherein the first optically transmissive layer separates the light blocking layer from the plurality of microlenses.
13. A method of manufacturing a sensor package comprising:
- bonding an image sensor wafer to a digital signal processor wafer;
- coupling a light blocking layer along a perimeter of a surface of a first optically transmissive layer of one or more optically transmissive layers;
- coupling the one or more optically transmissive layers over the image sensor wafer, wherein the surface of the first optically transmissive layer coupled to the light blocking layer is positioned closest to the image sensor wafer than other surfaces of the one or more optically transmissive layers;
- singulating the image sensor wafer, the digital signal processor wafer, and the one or more optically transmissive layers to obtain an image sensor die, a digital signal processor die, and an optically transmissive cover, respectively; and
- applying a mold compound to encapsulate one or more edges of the image sensor die, the digital signal processor die, and the optically transmissive cover.
14. The method of claim 13, further comprising:
- forming a color filter array over the image sensor wafer; and
- forming a plurality of microlenses over the color filter array.
15. The method of claim 13, wherein the optically transmissive layers includes a transparent or translucent layer.
16. The method of claim 13, wherein optically transmissive layers includes a low refractive index layer.
17. The method of claim 13, wherein the coupling the light blocking layer further comprises:
- applying a mask layer on the first optically transmissive layer; and
- patterning the mask layer.
18. The method of claim 13, wherein coupling the light blocking layer to the first optically transmissive layer is done before coupling the first optically transmissive layer over the image sensor wafer.
19. The method of claim 13, wherein coupling the light blocking layer to the first optically transmissive layer is done after coupling the first optically transmissive layer over the image sensor wafer.
Type: Application
Filed: Sep 7, 2022
Publication Date: Dec 29, 2022
Applicant: SEMICONDUCTOR COMPONENTS INDUSTRIES, LLC (Phoenix, AZ)
Inventors: Oswald L. SKEETE (Phoenix, AZ), Brian Anthony VAARTSTRA (Nampa, ID), Derek GOCHNOUR (Boise, ID)
Application Number: 17/930,111