CN107994014B - image sensor - Google Patents

Abstract

An image sensor includes a visible light receiving unit and an infrared light receiving unit. The visible light receiving unit is used to receive visible light, and the infrared light receiving unit is used to receive infrared light. The infrared light receiving unit includes: an infrared light photodiode, at least one white filter layer, and at least one infrared light transmission filter layer. The at least one white filter layer and the at least one infrared light transmission filter layer are both disposed on the infrared light photodiode. The infrared light passes through the at least one white filter layer and the at least one infrared light transmission filter layer and is received by the infrared light photodiode.

Description

image sensor

technical field

The present invention relates to an image sensor, and more particularly, to an image sensor with infrared light sensing function.

Background technique

With the development of access control system and security system, biometric technology that uses human body characteristics to confirm personal identity has gradually become popular. Iris recognition technology with high reliability is one of the popular biometric recognition technologies. When the iris recognition technology is applied to electronic devices, such as smart phones, the smart phones need image sensors that can receive visible light and infrared light respectively to realize the iris recognition function. Conventional image sensors have two distinct parts to receive visible light and infrared light, respectively.

SUMMARY OF THE INVENTION

The present invention provides an image sensor including a visible light receiving part and an infrared light receiving part. The visible light receiving part is used for receiving visible light, and the infrared light receiving part is used for receiving infrared light. The infrared light receiving part includes: an infrared light photodiode, at least one white filter layer and at least one infrared light penetrating filter layer. At least one white filter layer and at least one infrared light transmission filter layer are both disposed on the infrared light photodiode. The infrared light passes through at least one white filter layer and at least one infrared light transmits the filter layer to be received by the infrared light photodiode.

Description of drawings

A better understanding of aspects of the present disclosure can be obtained from the following detailed description taken in conjunction with the accompanying drawings. It should be noted that, according to standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or decreased in order to clarify the discussion.

FIG. 1 is a cross-sectional view illustrating an image sensor according to a first embodiment of the present invention.

2 is a cross-sectional view illustrating an image sensor according to a second embodiment of the present invention.

3 is a cross-sectional view illustrating an image sensor according to a third embodiment of the present invention.

4 is a cross-sectional view illustrating an image sensor according to a fourth embodiment of the present invention.

5 is a cross-sectional view illustrating an image sensor according to a fifth embodiment of the present invention.

6 is a cross-sectional view illustrating an image sensor according to a sixth embodiment of the present invention.

7 is a cross-sectional view illustrating an image sensor according to a seventh embodiment of the present invention.

8 is a cross-sectional view illustrating an image sensor according to an eighth embodiment of the present invention.

Description of reference numbers:

100, 200, 300, 400, 500, 600, 700, 800: Image Sensor

110, 210, 510, 610: Visible light receiving part

112: Visible light sensing layer

114, 514: Color filter layer

114a: red filter unit

114b: Blue filter unit

114c: Green filter unit

116, 516: Infrared light cut-off filter layer

120, 220, 320, 420, 520, 620, 720, 820: Infrared light receiving part

122: Infrared light sensing layer

124, 324, 325, 424, 524, 624, 724, 725, 825: White filter layer

126, 226, 326, 327, 526, 726, 727: Infrared light penetration filter layer

ML: Microlens layer

PL1, PL2, PL3, PL4: flat layers

SP: Spacer layer

WA: Wafer Layer

Detailed ways

This disclosure provides many different embodiments or examples for implementing different features of this disclosure. To simplify the present disclosure, specific examples of some components and layouts are described below. Of course, these are merely examples and are not intended to limit the present disclosure. For example, if it is mentioned in the following description that the first feature is formed on the second feature, this may include an embodiment in which the first feature and the second feature are in direct contact; this may also include an embodiment between the first feature and the second feature Embodiments of other features are formed such that the first feature is not in direct contact with the second feature. Furthermore, the present disclosure may repeat graphical symbols and/or text in various instances. This repetition is for the purpose of brevity and clarity and does not in itself determine the relationship between the various embodiments and/or arrangements discussed.

Furthermore, spatially relative terms, such as lower, lower, lower, upper, higher, etc., are used to readily explain the relationship between one element or feature and another element or feature in the illustrations. These spatially relative terms encompass, in addition to the orientation depicted in the figures, different orientations in which the device is used or operated. These devices may also be rotated (eg, rotated 90 degrees or to other orientations), and the spatially relative descriptions used herein may likewise be interpreted accordingly.

FIG. 1 is a cross-sectional view illustrating an image sensor 100 according to a first embodiment of the present invention. As shown in FIG. 1 , the image sensor 100 includes a visible light receiving part 110 and an infrared light receiving part 120 . The visible light receiving part 110 is used for receiving visible light, and the infrared light receiving part 120 is used for receiving infrared light.

As shown in FIG. 1 , the visible light receiving part 110 includes a visible light sensing layer 112 , a color filter layer 114 and an infrared light cut filter layer 116 . The color filter layer 114 and the IR Cut filter layer 116 are both disposed on the visible light sensing layer 112 to provide colored light to the visible light sensing layer 112 . The visible light sensing layer 112 is used for receiving visible light to generate a main image signal accordingly. In this embodiment, the visible light sensing layer 112 includes at least one photodiode to sense color light. The photodiode may be a complementary metal oxide semiconductor (CMOS) diode. However, embodiments of the present invention are not limited thereto.

The color filter layer 114 is used to provide colored light. In this embodiment, the color filter layer 114 includes a red filter unit 114a, a blue filter unit 114b, and a green filter unit 114c, but the embodiments of the present invention are not limited thereto. The infrared light cut filter layer 116 is used to cut off infrared light. In other words, when the colored light passes through the infrared light cut filter layer 116, the infrared light cut filter layer 116 can block the transmission of the infrared light. In this embodiment, the infrared light cut filter layer 116 blocks light with a wavelength greater than 850 nanometers, but the embodiments of the present invention are not limited thereto. Furthermore, in this embodiment, the infrared light cut-off layer 116 is disposed between the color filter layer 114 and the visible light sensing layer 112 , but the embodiment of the present invention is not limited thereto.

As shown in FIG. 1 , the infrared light receiving part 120 includes an infrared light sensing layer 122 , a white light filter layer 124 and an infrared light pass filter layer 126 . The white filter layer 124 and the infrared light transmission filter layer 126 are disposed on the infrared light sensing layer 122 to provide infrared light to the infrared light sensing layer 122 . The infrared light sensing layer 122 is used for receiving infrared light to generate auxiliary image signals accordingly. In this embodiment, the infrared light sensing layer 122 includes at least one photodiode to sense infrared light. The photodiode may be a complementary metal oxide semiconductor diode. However, embodiments of the present invention are not limited thereto.

The infrared light penetrates the filter layer 126 to cut visible light. In other words, when light passes through the infrared light transmission filter layer 126, the infrared light transmission filter layer 126 may block the transmission of visible light. In this embodiment, the infrared light penetrating filter layer 126 blocks light with a wavelength of less than 850 nanometers, but the embodiments of the present invention are not limited thereto. The white filter layer 124 is used to pass infrared light therethrough. In this embodiment, the white filter layer 124 is a white photoresist, but the embodiments of the present invention are not limited thereto. Furthermore, in this embodiment, the white filter layer 124 is disposed between the infrared light transmission filter layer 126 and the infrared light sensing layer 122 , but the embodiment of the present invention is not limited thereto.

As shown in FIG. 1 , the visible light receiving portion 110 and the infrared light receiving portion 120 further include a wafer layer WA, a flat layer PL1 , a spacer layer SP, and a microlens layer ML. The wafer layer WA is used to provide a substrate on which the infrared cut filter layer 116 and the white filter layer 124 are formed. In this embodiment, the wafer layer WA is a glass wafer, but the embodiment of the present invention is not limited thereto.

The flat layer PL1 is formed on the infrared light cut filter layer 116 and the white light filter layer 124 to provide a flat surface on which the color filter layer 114 and the infrared light transmission filter layer 126 are disposed. The flat layer PL1 also provides a good interface to assist the color filter layer 114 and the infrared light transmission filter layer 126 to be attached to the flat layer PL1. It should be noted that, in this embodiment, the thickness of the infrared light cut filter layer 116 is substantially equal to the thickness of the white filter layer 124 .

The spacer layer SP is located on the color filter layer 114 and the infrared light transmission filter layer 126 to provide a flat surface on which the microlens layer ML is disposed. It should be noted that, in this embodiment, the thickness of the color filter layer 114 is substantially equal to the thickness of the infrared light transmission filter layer 126 . The microlens layer ML is used for collecting infrared light and visible light. Specifically, when the image sensor 100 is used to sense an object (eg, an iris), the object is focused by the microlens layer ML. Furthermore, the focus of the image sensor 100 can be adjusted by changing the thickness of the microlens layer ML.

It should be noted that the material of the microlens layer ML can be epoxy resin, optical glue, acrylic material (polymethylmethacrylates, PMMAs), polyurethane plastic material (polyurethanes, PUs), silicone material (polydimethylsiloxane, PDMS) or other thermal curing or light hardened light-transmitting material, but embodiments of the present invention are not limited thereto.

Compared with the conventional image sensor, because the white filter layer 124 of the image sensor 100 is disposed in the infrared light receiving part 120, the overall thickness of the infrared light penetrating filter layer 126 is reduced, so the image sensor 100 The received infrared light has less loss of light intensity. Therefore, the infrared light received by the image sensor 100 has a better light intensity to meet the needs of the user.

It should be noted that the configuration of the infrared light transmission filter layer 126 and the white filter layer 124 is not limited to the first embodiment. In some embodiments of the present invention, the positions of the infrared light penetrating filter layer 126 and the white filter layer 124 are interchanged.

FIG. 2 is a cross-sectional view illustrating an image sensor 200 according to a second embodiment of the present invention. As shown in FIG. 2 , the image sensor 200 includes a visible light receiving portion 210 and an infrared light receiving portion 220 , wherein the visible light receiving portion 210 includes a flat layer PL2 , and the infrared light receiving portion 220 includes an infrared light transmitting filter layer 226 . It should be noted that the planarization layer PL2 is similar to the planarization layer PL1 , and the infrared light transmission filter layer 226 is similar to the infrared light transmission filter layer 126 . The structure of the image sensor 200 is similar to that of the image sensor 100 , except that the flat layer PL2 is only located in the visible light receiving part 210 . It should be noted that, in this embodiment, the sum of the thickness of the color filter layer 114 and the thickness of the flat layer PL2 is substantially equal to the thickness of the infrared light transmission filter layer 226 . Similar to the image sensor 100, the infrared light received by the image sensor 200 has a better light intensity to meet the needs of the user.

It should be noted that the configuration of the infrared light transmission filter layer 226 and the white filter layer 124 is not limited to the second embodiment. In some embodiments of the present invention, the positions of the infrared light penetrating filter layer 226 and the white filter layer 124 are interchanged.

FIG. 3 is a cross-sectional view illustrating an image sensor 300 according to a third embodiment of the present invention. As shown in FIG. 3 , the image sensor 300 includes a visible light receiving portion 110 and an infrared light receiving portion 320 , wherein the infrared light receiving portion 220 includes infrared light penetrating filter layers 326 and 327 and white light filter layers stacked alternately with each other. Layers 324, 325. It should be noted that the infrared light transmission filter layers 326 , 327 are similar to the infrared light transmission filter layer 126 , and the white filter layers 324 , 325 are similar to the white filter layer 124 . The structure of the image sensor 300 is similar to that of the image sensor 100, except that the infrared light transmission filter layer 126 is replaced by the infrared light transmission filter layer 326 and the white filter layer 324, and the white filter The optical layer 124 is replaced by the infrared light transmission filter layer 327 and the white filter layer 325 . It should be noted that, in this embodiment, the thickness of the color filter layer 114 is substantially equal to the sum of the thickness of the infrared light transmission filter layer 326 and the thickness of the white filter layer 324, and in this embodiment, The thickness of the infrared light cut filter layer 116 is substantially equal to the sum of the thickness of the infrared light transmission filter layer 327 and the thickness of the white filter layer 325 . Similar to the image sensor 100, the infrared light received by the image sensor 300 has a better light intensity to meet the needs of the user.

It should be noted that the configurations of the infrared light transmission filter layers 326 and 327 and the white filter layers 324 and 325 are not limited to the third embodiment. In some embodiments of the present invention, the positions of the infrared light penetrating filter layer 326 and the white filter layer 324 are interchanged. In some other embodiments of the present invention, the positions of the infrared light penetrating filter layer 327 and the white filter layer 325 are interchanged.

FIG. 4 is a cross-sectional view illustrating an image sensor 400 according to a fourth embodiment of the present invention. As shown in FIG. 4 , the image sensor 400 includes a visible light receiving portion 210 and an infrared light receiving portion 420 , wherein the infrared light receiving portion 420 includes a white filter layer 424 . It should be noted that white filter layer 424 is similar to white filter layer 124 . The structure of the image sensor 400 is similar to that of the image sensor 300 , except that the flat layer PL2 is only located in the visible light receiving part 210 . It should be noted that, in this embodiment, the sum of the thickness of the color filter layer 114 and the thickness of the flat layer PL2 is substantially equal to the sum of the thickness of the infrared light transmission filter layer 326 and the thickness of the white filter layer 424 . Similar to the image sensor 300 , the infrared light received by the image sensor 400 has a better light intensity to meet the needs of the user.

It should be noted that the configurations of the infrared light transmission filter layers 326 and 327 and the white filter layers 424 and 325 are not limited to the fourth embodiment. In some embodiments of the present invention, the positions of the infrared light transmission filter layer 326 and the white filter layer 424 are interchanged. In some other embodiments of the present invention, the positions of the infrared light penetrating filter layer 327 and the white filter layer 325 are interchanged.

FIG. 5 is a cross-sectional view illustrating an image sensor 500 according to a fifth embodiment of the present invention. As shown in FIG. 5 , the image sensor 500 includes a visible light receiving portion 510 and an infrared light receiving portion 520, wherein the visible light receiving portion 510 includes a flat layer PL3, a color filter layer 514 and an infrared light cut filter layer 516, and the infrared light The receiving part 520 includes a flat layer PL3 , a white filter layer 524 and an infrared light transmission filter layer 526 . It should be noted that the planarization layer PL3 is similar to the planarization layer PL1, the color filter layer 514 is similar to the color filter layer 114, the IR cut filter layer 516 is similar to the IR cut filter layer 116, and the white filter layer 524 is similar In the white filter layer 124 , and the infrared light transmission filter layer 526 is similar to the infrared light transmission filter layer 126 . The structure of the image sensor 500 is similar to that of the image sensor 100, except that the color filter layer 514 is located between the infrared light cut filter layer 516 and the flat layer PL3. It should be noted that, in this embodiment, the thickness of the color filter layer 514 is substantially equal to the thickness of the white filter layer 524, and the thickness of the infrared light cut filter layer 516 is the same as the thickness of the infrared light penetration filter layer 526. The thicknesses are substantially equal. Similar to the image sensor 100, the infrared light received by the image sensor 500 has a better light intensity to meet the needs of the user.

It should be noted that the configuration of the infrared light transmission filter layer 526 and the white filter layer 524 is not limited to the fifth embodiment. In some embodiments of the present invention, the positions of the infrared light transmission filter layer 526 and the white filter layer 524 are interchanged.

FIG. 6 is a cross-sectional view illustrating an image sensor 600 according to a sixth embodiment of the present invention. As shown in FIG. 6 , the image sensor 600 includes a visible light receiving portion 610 and an infrared light receiving portion 620 , wherein the visible light receiving portion 610 includes a flat layer PL4 , and the infrared light receiving portion 620 includes a white filter layer 624 . It should be noted that the planarization layer PL4 is similar to the planarization layer PL1 and the white filter layer 624 is similar to the white filter layer 124 . The structure of the image sensor 600 is similar to that of the image sensor 500 , except that the flat layer PL4 is only located in the visible light receiving part 610 . It should be noted that, in this embodiment, the sum of the thickness of the color filter layer 514 and the thickness of the flat layer PL4 is substantially equal to the thickness of the white filter layer 624 . Similar to the image sensor 500, the infrared light received by the image sensor 600 has a better light intensity to meet the needs of the user.

It should be noted that the configuration of the infrared light transmission filter layer 526 and the white filter layer 624 is not limited to the sixth embodiment. In some embodiments of the present invention, the positions of the infrared light transmission filter layer 526 and the white filter layer 624 are interchanged.

FIG. 7 is a cross-sectional view illustrating an image sensor 700 according to a seventh embodiment of the present invention. As shown in FIG. 7 , the image sensor 700 includes a visible light receiving portion 510 and an infrared light receiving portion 720 , wherein the infrared light receiving portion 720 includes infrared light transmission filter layers 726 and 727 and white light filter layers alternately stacked on each other. Layers 724, 725. It should be noted that the infrared light transmission filter layers 726 , 727 are similar to the infrared light transmission filter layer 126 , and the white filter layers 724 , 725 are similar to the white filter layer 124 . The structure of the image sensor 700 is similar to that of the image sensor 500, except that the infrared light transmission filter layer 526 is replaced by the infrared light transmission filter layer 726 and the white filter layer 724, and the white filter The optical layer 524 is replaced by the infrared light transmission filter layer 727 and the white filter layer 725 . It should be noted that, in this embodiment, the thickness of the color filter layer 514 is substantially equal to the sum of the thickness of the infrared light transmission filter layer 727 and the thickness of the white filter layer 725, and the infrared light cut filter layer The thickness of 516 is substantially equal to the sum of the thickness of the infrared light transmission filter layer 726 and the thickness of the white filter layer 724 . Similar to the image sensor 500, the infrared light received by the image sensor 700 has a better light intensity to meet the needs of the user.

It should be noted that the configuration of the infrared light transmission filter layers 726, 727 and the white filter layers 724, 725 is not limited to the third embodiment. In some embodiments of the present invention, the positions of the infrared light transmission filter layer 726 and the white filter layer 724 are interchanged. In some other embodiments of the present invention, the positions of the infrared light penetrating filter layer 727 and the white filter layer 725 are interchanged.

FIG. 8 is a cross-sectional view illustrating an image sensor 800 according to an eighth embodiment of the present invention. As shown in FIG. 8 , the image sensor 800 includes a visible light receiving portion 610 and an infrared light receiving portion 820 , wherein the infrared light receiving portion 820 includes a white filter layer 825 . It should be noted that white filter layer 825 is similar to white filter layer 124 . The structure of the image sensor 800 is similar to that of the image sensor 700 , except that the flat layer PL4 is only located in the visible light receiving part 610 . It should be noted that, in this embodiment, the sum of the thickness of the color filter layer 514 and the thickness of the flat layer PL4 is substantially equal to the sum of the thickness of the infrared light transmission filter layer 727 and the thickness of the white filter layer 825 . Similar to the image sensor 700 , the infrared light received by the image sensor 800 has a better light intensity to meet the needs of the user.

It should be noted that the configurations of the infrared light transmission filter layers 726 and 727 and the white filter layers 724 and 825 are not limited to the eighth embodiment. In some embodiments of the present invention, the positions of the infrared light transmission filter layer 726 and the white filter layer 724 are interchanged. In some other embodiments of the present invention, the positions of the infrared light penetrating filter layer 727 and the white filter layer 825 are interchanged.

In some embodiments of the present invention, the number of the white filter layers and the number of the infrared light transmission filter layers are both greater than 1, and the white filter layers and the infrared light transmission filter layers are alternately stacked on the infrared light on the sensing layer, but embodiments of the present invention are not limited thereto.

It can be seen from the above that the structure of the image sensor of the present invention can effectively improve the light intensity of the infrared light received by the image sensor to meet the needs of users, thereby reducing the subsequent analysis of optical signals on other instruments (such as video signal) difficulty.

The foregoing has outlined the features of several embodiments so that those skilled in the art may better understand 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, thereby achieving the same objectives and/or achieving the same advantages as the embodiments described herein . Those skilled in the art should also understand that these equivalent constructions do not depart from the spirit and scope of the present disclosure, and they can make various changes, substitutions and alterations without departing from the spirit and scope of the present disclosure.

Claims (15)

1. An image sensor, comprising:

a visible light receiving part for receiving a visible light; and

an infrared light receiving part for receiving an infrared light, wherein the infrared light receiving part comprises:

an infrared photodiode;

at least one white filter layer arranged on the infrared photodiode; and

at least one infrared light penetration filter layer arranged on the infrared light photodiode;

wherein

The infrared light penetrates through the at least one white filter layer and the at least one infrared light penetration filter layer and is received by the infrared light photodiode;

the visible light receiving part includes:

a visible light photodiode;

a color filter layer disposed on the visible light photodiode; and

an infrared light cut-off filter layer arranged on the visible light photodiode;

wherein the visible light passes through the color filter layer and the infrared light cut-off filter layer and is received by the visible light photodiode;

the number of the at least one white filter layer is greater than 1, the number of the at least one infrared light penetration filter layer is greater than 1, the white filter layers and the infrared light penetration filter layers are alternately stacked on the infrared light photodiode, and the sum of the thicknesses of the white filter layers and the infrared light penetration filter layers is equal to the sum of the thicknesses of the color filter layers and the infrared light stop filter layers.

2. The image sensor of claim 1, further comprising a wafer layer on the infrared photodiode and the visible photodiode, wherein a first portion of the wafer layer is within the visible light receiving portion and a second portion of the wafer layer is within the infrared light receiving portion.

3. The image sensor as claimed in claim 2, wherein the infrared light cut filter layer is located between the color filter layer and the visible light photodiode, and the first portion of the wafer layer is located between the infrared light cut filter layer and the visible light photodiode.

4. The image sensor as claimed in claim 2, wherein the color filter layer is located between the infrared light cut filter layer and the visible light photodiode, and the first portion of the wafer layer is located between the color filter layer and the visible light photodiode.

5. The image sensor as claimed in claim 2, wherein the at least one white filter layer is disposed between the at least one infrared light transmissive filter layer and the infrared photodiode, and the second portion of the wafer layer is disposed between the at least one white filter layer and the infrared photodiode.

6. The image sensor as claimed in claim 2, wherein the at least one infrared light-transmissive filter layer is disposed between the at least one white filter layer and the infrared photodiode, and the second portion of the wafer layer is disposed between the at least one infrared light-transmissive filter layer and the infrared photodiode.

7. The image sensor as claimed in claim 1, wherein the color filter layer comprises a red filter unit, a green filter unit and a blue filter unit.

8. The image sensor as claimed in claim 1, further comprising a planarization layer for providing a planarized surface, wherein the color filter layer is disposed on the planarized surface.

9. The image sensor as in claim 8, wherein the planarization layer is located within the visible light receiving portion and the infrared light receiving portion.

10. The image sensor as in claim 8, wherein the planarization layer is located within the visible light receiving portion.

11. The image sensor as claimed in claim 1, further comprising a micro-lens layer for collecting the visible light and the infrared light.

12. The image sensor as in claim 11, wherein the microlens layer is disposed on an uppermost layer of the image sensor.

13. The image sensor as in claim 11, wherein the microlens layer is located within the visible light receiving portion and the infrared light receiving portion.

14. The image sensor of claim 11 further comprising a spacer layer providing a planar surface, wherein the microlens layer is disposed on the planar surface.

15. The image sensor as in claim 14, wherein the spacer layer is located within the visible light receiving portion and the infrared light receiving portion.

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