The present disclosure relates to an image sensor, a manufacturing method and a chip of the same and a hand-held device adopting the chip; in particular, to an image sensor having a polarizing layer, a method for manufacturing the image sensor, an image sensing chip, and a hand-held device.
CMOS image sensors have been mass-produced and widely applied. Conventional image sensors may generate two-dimensional (2D) images and videos; recently, image sensors and systems capable of generating three-dimensional (3D) images attract widespread attention, these 3D image sensors can be used in applications such as facial recognition, augmented reality (AR), virtual reality (VR), drones, among others.
There are three main implementations of existing 3D image sensors: stereoscopic binocular, structured light, and time-of-flight (ToF).
The ToF approach uses specially designed pixels to determine the distance by measuring the time it takes for photons to fly and return; however, the current technology cannot generate a depth map with sufficient accuracy. In order to increase the accuracy of modeling and to reduce the cost, how to improve the accuracy of ToF sensors in a simple way has become an important task.
One purpose of the present disclosure is to disclose an image sensor, a manufacturing method and a chip of the same, and a hand-held device adopting the chip to address the above-mentioned issues.
One embodiment of the present disclosure discloses an image sensor, including a semiconductor substrate and a plurality of pixels, wherein each pixel of the plurality of pixels includes: a photosensitive sensor, disposed on the semiconductor substrate; a polarizing layer, disposed over the semiconductor substrate; a microlens, disposed over the polarizing layer so that the polarizing layer is between the microlens and the semiconductor substrate.
One embodiment of the present disclosure discloses a manufacturing method of an image sensor, including providing a semiconductor substrate; forming a polarizing layer over the semiconductor substrate; and forming a microlens over the polarizing layer.
One embodiment of the present disclosure discloses a chip, which includes the above-mentioned image sensor.
One embodiment of the present disclosure discloses a hand-held device, configured to perform the ToF detection, wherein the hand-held device includes: a display panel; and the above-mentioned image sensor.
Embodiments of the present disclosure incorporate a polarizing layer in an image sensor, which improves the accuracy of the ToF sensor.
The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. Specific examples of components and arrangements are described below to simplify the present disclosure. As could be appreciated, these are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and the second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and the second features, such that the first and the second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for the ease of the description to describe one element or feature's relationship with respect to another element(s) or feature(s) as illustrated in the drawings. The spatially relative terms are intended to encompass different directions of the device in use or operation in addition to the direction depicted in the figures. The apparatus may be otherwise oriented (e.g., rotated by 90 degrees or at other directions) and the spatially relative descriptors used herein may likewise be interpreted accordingly.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in the respective testing measurements. Also, as used herein, the term “about” generally means within 10%, 5%, 1%, or 0.5% of a given value or range. Alternatively, the term “about” means within an acceptable standard error of the mean when considered by one of ordinary skill in the art. As could be appreciated, other than in the operating/working examples, or unless otherwise expressly specified, all of the numerical ranges, amounts, values and percentages such as those for quantities of materials, durations of times, temperatures, operating conditions, ratios of amounts, and the likes thereof disclosed herein should be understood as modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the present disclosure and attached claims are approximations that can vary as desired. At the very least, each numerical parameter should at least be construed considering the number of reported significant digits and by applying ordinary rounding techniques. Ranges can be expressed herein as from one endpoint to another endpoint or between two endpoints. All ranges disclosed herein are inclusive of the endpoints unless specified otherwise.
The receiving module of conventional sensors uses the image sensor to determine the time point at which the light is reflected by the object to be determined. Due to the complex reflective behavior of light in the environment, the receiving module tends to pick up a lot of unwanted noise. In view of this, the present disclosure filters the received light by arranging a polarizing layer in the image sensor of the light signal receiving module of the ToF sensor, to increase the accuracy of the ToF sensor; the details will be described hereinafter. It should be noted that even though the image sensor of the present disclosure can improve the accuracy of existing ToF sensors, such application is not a limitation to the present disclosure. In other words, the image sensor of the present disclosure can also be applied in other scenarios other than the ToF sensor.
The semiconductor substrate 108 can be a bulk semiconductor substrate, such as a bulk silicon substrate or a silicon on insulator (SOI) substrate. The photosensitive sensor 106 is disposed on the semiconductor substrate 108. The microlens 102 is arranged over the backside of the semiconductor substrate 108, and the polarizing layer 104 is disposed between the microlens 102 and the semiconductor substrate 108. The design of the polarizing layer 104 makes it difficult for the light that is not in a specific direction to pass through; that is, the light first passes through the microlens 102 and then enters the polarizing layer 104, and in this way, instead of allowing all light passing through the microlens 102 to enter the photosensitive sensor 106, only light with a particular direction can enter the photosensitive sensor 106 according to the design of the polarizing layer 104.
In some embodiments, a color filter can be further disposed between the microlens 102 and the polarizing layer 104 depending on the need. Also, in some embodiments, an anti-reflection layer and/or a buffer layer can be disposed between the polarizing layer 104 and the semiconductor substrate 108.
The grid layer 202 has a plurality of openings so that the underlying semiconductor substrate 108 is exposed, and the grid layer 202 is divided into a plurality of grid lines (e.g., a plurality of metal grid lines) by the plurality of openings; the number of the grid lines of the grid layer 202 as shown in
Specifically, the grid layer 202 of all of the pixels 200, 300, 400, and 500 has grid lines that surround the peripheral of the pixels, the grid layer 202 of the pixels 200, 300, 400, and 500 differs in the directions of the respective parallel grid lines thereof. As shown in
The pixel arrangement shown in
In
It should be noted that, the implementation of using the polarizing layer between the microlens and the photosensitive sensor to improve the accuracy of the ToF sensor is not limited to the backside illumination image sensor, and in some embodiments, it can be implemented using a front-side illuminated (FSI) image sensor.
The semiconductor substrate 1008 can be a bulk semiconductor substrate, such as, a bulk silicon substrate or silicon on insulator (SOI) substrate. The photosensitive sensor 1006 is disposed on the semiconductor substrate 1008. The microlens 1002 is arranged on the front side the semiconductor substrate 1008 so that back-end-of-line stack 1010 is disposed between the microlens 1002 and the semiconductor substrate 1008.
In the present embodiment, the metallization layer 1004 in the back-end-of-line stack 1010 is shaped so that it is used as the grid layer to achieve the effect of a polarizing layer, so that it is difficult for light that is not in a specific direction to pass through. That is, light first passes through the microlens 1002 and then enters the metallization layer (polarizing layer) 1004, and in this way, instead of allowing all light passing through the microlens 1002 to enter the photosensitive sensor 1006, only light with a particular direction can enter the photosensitive sensor 1006 according to the design of the metallization layer (polarizing layer) 1004. The metallization layer (polarizing layer) 1004 serving as the polarizing layer may have a shape that is the same as or similar to the shape of the grid layers in the image sensors 200, 300, 400, and/or 500; for example, it includes a plurality of grid lines that are disposed in parallel and covers the entire semiconductor substrate 1008; in some embodiments, the plurality of parallel grid lines are equally spaced.
In the present embodiment, the metallization layer 1004 of any layer of the back-end-of-line stack 1010 may be used as the polarizing layer, and the present disclosure is not particularly limited. A color filter may be further disposed between the microlens 1002 and the back-end-of-line stack 1010 depending on the need.
The present disclosure further provides a chip, which includes the image sensor 100/1000, wherein the polarizing layer 104/1004 of the image sensor 100/1000 may have the shape of the image sensors 200, 300, 400, and/or 500. The present disclosure further provides a hand-held device, wherein
The foregoing outlines features of several embodiments so that those skilled in the art may better understand various aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of embodiments introduced herein. Those skilled in the art should also realize that such equivalent embodiments still fall within the spirit and scope of the present disclosure, and they may make various changes, substitutions, and alterations thereto without departing from the spirit and scope of the present disclosure.
The present disclosure is a continuation of international application No. PCT/CN2019/098285, filed on Jul. 30, 2019, which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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Parent | PCT/CN2019/098285 | Jul 2019 | US |
Child | 17027612 | US |