TWI630711B - Image sensor - Google Patents

Abstract

An image sensor includes a visible light receiving portion and an infrared light receiving portion. The visible light receiving portion is configured to receive visible light, and the infrared light receiving portion is configured to receive infrared light. The infrared light receiving portion 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 penetrating filter layer are disposed on the infrared light photodiode. The infrared light is received by the infrared light photodiode through at least one white filter layer and at least one infrared light penetrating the filter layer.

Description

Image sensor

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

With the development of access control systems and security systems, biometric techniques that use human features to confirm personal identity are gaining popularity. The highly reliable iris recognition technology is one of the popular biometric technologies. When the iris recognition technology is applied to an electronic device, such as a smart phone, the smart phone needs an image sensor capable of receiving visible light and infrared light, respectively, to realize the iris recognition function. Conventional image sensors have two distinct parts to receive visible and infrared light, respectively.

The invention provides an image sensor comprising a visible light receiving portion and an infrared light receiving portion. The visible light receiving portion is configured to receive visible light, and the infrared light receiving portion is configured to receive infrared light. The infrared light receiving portion 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 penetrating filter layer are disposed on the infrared light photodiode. Wherein the infrared light passes through at least one white filter layer and at least one The infrared light penetrates the filter layer and is received by the infrared light photodiode.

100, 200, 300, 400, 500, 600, 700, 800‧‧‧ image sensors

110, 210, 510, 610 ‧ ‧ visible light receiving department

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

120, 220, 320, 420, 520, 620, 720, 820‧‧‧ infrared light receiving unit

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 transmission filter

ML‧‧‧microlens layer

PL1, PL2, PL3, PL4‧‧‧ flat layer

SP‧‧‧ spacer

WA‧‧‧ wafer layer

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

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

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

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

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

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

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

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

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

The disclosure provides many different embodiments or examples for implementing the various features disclosed herein. In order to simplify the disclosure, specific examples of components and layouts are described below. Of course, these are merely examples and are not intended to limit the 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 is in direct contact with the second feature; this may also include between the first feature and the second feature. Embodiments of other features are formed that make the first feature not in direct contact with the second feature. Moreover, the disclosure may repeat the symbols and/or text in various examples. This repetition is for the purpose of brevity and clarity, but does not in itself determine the relationship between the various embodiments and/or arrangements discussed.

Furthermore, spatially relative terms such as "lower", "lower", """"""""""" These spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the drawings. These devices can also be rotated (e.g., rotated 90 degrees or rotated to other directions), and the spatially relative descriptions used herein can also be interpreted accordingly.

1 is a cross-sectional view of an image sensor 100 in accordance with a first embodiment of the present invention. As shown in FIG. 1 , the image sensor 100 includes a visible light receiving unit 110 and an infrared light receiving unit 120 . The visible light receiving unit 110 is configured to receive visible light, and the infrared light receiving unit 120 is configured to receive infrared light.

As shown in FIG. 1 , the visible light receiving unit 110 includes a visible light sensing layer 112 , a color filter layer 114 , and an infrared light blocking filter layer 116 . color The 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 configured to receive 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 colored light. The photodiode can be a complementary metal oxide semiconductor (CMOS) diode. However, embodiments of the invention are not limited thereto.

The color filter layer 114 is used to provide colored light. In the present embodiment, the color filter layer 114 includes a red filter unit 114a, a blue filter unit 114b, and a green filter unit 114c, but embodiments of the present invention are not limited thereto. The infrared light cut filter layer 116 is used to intercept 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 blocks the transmission of the infrared light. In the present embodiment, the infrared light cut filter layer 116 blocks light having a wavelength of more than 850 nm, but embodiments of the present invention are not limited thereto. Furthermore, in the present embodiment, the infrared light blocking layer 116 is disposed between the color filter layer 114 and the visible light sensing layer 112, but embodiments of the present invention are not limited thereto.

As shown in FIG. 1, the infrared light receiving portion 120 includes an infrared light sensing layer 122, a white filter layer 124, and an infrared light penetrating (IR Pass) filter layer 126. The white filter layer 124 and the infrared light penetrating 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 configured to receive infrared light to generate an auxiliary image signal accordingly. In this embodiment, the infrared light sensing layer 122 includes at least one photodiode to sense infrared light. The photodiode can be a complementary MOS diode. However, this Embodiments of the invention are not limited thereto.

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

As shown in FIG. 1, the visible light receiving unit 110 and the infrared light receiving unit 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 light cut filter layer 116 and the white filter layer 124 are formed. In the present embodiment, the wafer layer WA is a glass wafer, but embodiments of the present invention are not limited thereto.

The flat layer PL1 is formed on the infrared light cut filter layer 116 and the white 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 penetrating filter layer 126 to be attached to the flat layer PL1. It should be noted that in the present 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 the present embodiment, the thickness of the color filter layer 114 and the infrared light The thickness of the penetrating filter layer 126 is substantially equal. The microlens layer ML is used to collect infrared light and visible light. Specifically, when the image sensor 100 is used to sense an object such as an iris, the object is focused through 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 may be epoxy resin, optical glue, polymethylmethacrylates (PMMAs), polyurethane plastics (PUs), polydimethylsiloxane (PDMS) or other thermosetting. Or a light-hardened light-transmitting material, but embodiments of the invention are not limited thereto.

Compared with the conventional image sensor, the image sensor 100 is disposed in the infrared light receiving portion 120 because the white filter layer 124 is disposed, so that the overall thickness of the infrared light penetrating filter layer 126 is reduced. Therefore, the image sensor 100 is reduced. The received infrared light has a small 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 penetrating filter layer 126 and the white filter layer 124 is not limited to the first embodiment. In some embodiments of the invention, the infrared light penetrating filter layer 126 is interchanged with the location of the white filter layer 124.

2 is a cross-sectional view of an image sensor 200 in accordance with 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 penetrating filter layer 226 . It should be noted that the flat layer PL2 is similar to the flat layer PL1, and the infrared light penetrating filter layer 226 is similar to the infrared light penetrating filter layer 126. Image sensing The structure of the device 200 is similar to that of the image sensor 100 except that the flat layer PL2 is located only in the visible light receiving portion 210. It should be noted that in the present 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 penetrating 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 penetrating filter layer 226 and the white filter layer 124 is not limited to the second embodiment. In some embodiments of the invention, the infrared light penetrating filter layer 226 is interchanged with the location of the white filter layer 124.

3 is a cross-sectional view of an image sensor 300 in accordance with 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, 327 and a white filter layer that are alternately stacked with each other. 324, 325. It should be noted that the infrared light penetrating filter layers 326, 327 are similar to the infrared light penetrating 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 penetrating filter layer 126 is replaced by the infrared light penetrating filter layer 326 and the white filter layer 324, and the white filter The light layer 124 is replaced by an infrared light penetrating filter layer 327 and a 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 penetrating 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 thickness of the infrared light penetrating filter layer 327 and the white filter layer. The sum of the thicknesses of 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 configuration of the infrared light penetrating filter layers 326, 327 and the white filter layers 324, 325 is not limited to the third embodiment. In some embodiments of the invention, the infrared light penetrating filter layer 326 is interchanged with the set position of the white filter layer 324. In some other embodiments of the invention, the infrared light penetrating filter layer 327 is interchanged with the location of the white filter layer 325.

4 is a cross-sectional view of an image sensor 400 in accordance with 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 the white filter layer 424 is similar to the 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 located only in the visible light receiving portion 210. It should be noted that in the present 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 configuration of the infrared light penetrating filter layers 326, 327 and the white filter layers 424, 325 is not limited to the fourth embodiment. In some embodiments of the invention, the infrared light penetrating filter layer 326 is interchanged with the location of the white filter layer 424. In some other embodiments of the invention, the infrared light penetrating filter layer 327 is interchanged with the location of the white filter layer 325.

FIG. 5 is a view showing a sense of image according to a fifth embodiment of the present invention. A cross-sectional view of the detector 500. 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 portion 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 flat layer PL3 is similar to the flat layer PL1, the color filter layer 514 is similar to the color filter layer 114, and the infrared light cut filter layer 516 is similar to the infrared light cut filter layer 116, and the white filter layer 524 is similar. The white filter layer 124 is similar to the infrared light penetrating 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 and the infrared light penetrates the 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 penetrating filter layer 526 and the white filter layer 524 is not limited to the fifth embodiment. In some embodiments of the invention, the infrared light penetrating filter layer 526 is interchanged with the location of the white filter layer 524.

FIG. 6 is a cross-sectional view of an image sensor 600 in accordance with 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 flat layer PL4 is similar to the flat 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 located only in the visible light receiving portion 610. It should be noted that in the present 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 penetrating filter layer 526 and the white filter layer 624 is not limited to the sixth embodiment. In some embodiments of the invention, the infrared light penetrating filter layer 526 is interchanged with the location of the white filter layer 624.

FIG. 7 is a cross-sectional view showing an image sensor 700 in accordance with 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 penetrating filter layers 726, 727 and a white filter layer that are alternately stacked with each other. 724, 725. It should be noted that the infrared light penetrating filter layers 726, 727 are similar to the infrared light penetrating 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 penetrating filter layer 526 is replaced by the infrared light penetrating filter layer 726 and the white filter layer 724, and the white filter The light layer 524 is replaced by an infrared light penetrating filter layer 727 and a 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 penetrating 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 red The sum of the thickness of the outer light penetrating 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 penetrating filter layers 726, 727 and the white filter layers 724, 725 is not limited to the third embodiment. In some embodiments of the invention, the infrared light penetrating filter layer 726 is interchanged with the location of the white filter layer 724. In some other embodiments of the invention, the infrared light penetrating filter layer 727 is interchanged with the set position of the white filter layer 725.

FIG. 8 is a cross-sectional view of an image sensor 800 in accordance with 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 the white filter layer 825 is similar to the 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 located only in the visible light receiving portion 610. It should be noted that in the present 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 penetrating 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 configuration of the infrared light penetrating filter layers 726, 727 and the white filter layers 724, 825 is not limited to the eighth embodiment. In some embodiments of the invention, the infrared light penetrating filter layer 726 is interchanged with the location of the white filter layer 724. In some other embodiments of the invention, the infrared light penetrating filter layer 727 is interchanged with the set position of the white filter layer 825.

In some embodiments of the present invention, the number of white filter layers and the number of infrared light penetrating filter layers are both greater than 1, and the white filter layer and the infrared light penetrating filter layer are alternately stacked on each other in infrared light perception. The layer is measured, but embodiments of the 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 the user, thereby reducing the subsequent analysis of optical signals on other instruments (eg, Difficulty in video signal).

The features of several embodiments are summarized above, and those skilled in the art will be able to understand the aspects of the disclosure. Those skilled in the art will appreciate that the present disclosure can be readily utilized 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. . It should be understood by those skilled in the art that the invention may be made without departing from the spirit and scope of the disclosure.

Claims (17)

An image sensor includes: a visible light receiving portion for receiving a visible light; and an infrared light receiving portion for receiving an infrared light, wherein the infrared light receiving portion comprises: an infrared light photodiode; at least one a white filter layer disposed on the infrared light photodiode; and at least one infrared light penetrating the filter layer disposed on the infrared light photodiode; wherein the infrared light passes through the at least one white filter layer The at least one infrared light passes through the filter layer and is received by the infrared light photodiode. The image sensor of claim 1, wherein the visible light receiving portion comprises: a visible light photodiode; a color filter layer disposed on the visible light diode; and an infrared light cut filter And a layer disposed on the visible light diode; wherein the visible light passes through the color filter layer and the infrared light cut filter layer and is received by the visible light diode. The image sensor of claim 2, further comprising a wafer layer located in the infrared light dipole and the visible light In the photodiode, a first portion of the wafer layer is located in the visible light receiving portion, and a second portion of the wafer layer is located in the infrared light receiving portion. The image sensor of claim 3, wherein the infrared light blocking filter layer is located between the color filter layer and the visible light diode, and the first portion of the wafer layer is located The infrared light cutoff filter layer is between the visible light photodiode. The image sensor of claim 3, wherein the color filter layer is located between the infrared light blocking filter layer and the visible light diode, and the first portion of the wafer layer is located The color filter layer is between the visible light diode. The image sensor of claim 3, wherein the at least one white filter layer is located between the at least one infrared light penetrating filter layer and the infrared light photodiode, and the wafer layer is The second portion is located between the at least one white filter layer and the infrared light diode. The image sensor of claim 3, wherein the at least one infrared light transmission filter layer is located between the at least one white light filter layer and the infrared light photodiode, and the wafer layer is The second portion is located between the at least one infrared light penetrating filter layer and the infrared light photodiode. The image sensor of claim 2, wherein the color filter layer comprises a red filter unit, a green filter unit, and a blue filter unit. The image sensor of claim 2, further comprising a flat layer for providing a flat surface, wherein the color filter layer is disposed on the flat surface. The image sensor of claim 9, wherein the flat layer is located in the visible light receiving portion and the infrared light receiving portion. The image sensor of claim 9, wherein the flat layer is located in the visible light receiving portion. The image sensor of claim 1, further comprising a microlens layer for collecting the visible light and the infrared light. The image sensor of claim 12, wherein the microlens layer is located at an uppermost layer of the image sensor. The image sensor of claim 12, wherein the microlens layer is located in the visible light receiving portion and the infrared light receiving portion. The image sensor of claim 12, further comprising a spacer layer for providing a flat surface, wherein the microlens layer is disposed on the flat surface. The image sensor of claim 15, wherein the spacer layer is located in the visible light receiving portion and the infrared light receiving portion. The image sensor of claim 1, wherein the number of the at least one white filter layer is greater than 1, and the number of the at least one infrared light penetrating filter layer is greater than 1, and the white filters are The layer and the infrared light penetrating filter layers are alternately stacked on the infrared light photodiode.