CN115705740A - Optical fingerprint chip, processing method thereof and electronic equipment - Google Patents

Abstract

The invention provides an optical fingerprint chip, a processing method thereof and electronic equipment, and relates to the technical field of optical fingerprint identification under a screen, wherein the optical fingerprint chip comprises: a substrate; a photosensitive region disposed on the substrate, the photosensitive region including a photoelectric conversion device; a plurality of metal layer units arranged above the substrate, wherein one metal layer unit comprises a plurality of metal layers which are arranged in a direction perpendicular to the substrate with gaps, and an optical channel corresponding to at least one photoelectric conversion device is formed between adjacent metal layer units, so that incident light can reach the photoelectric conversion device through the optical channel; and the shielding layer is arranged in the optical channel and shields at least part of the side of the metal layer unit, so that the incident light cannot enter a gap between adjacent metal layers. This application can absorb the noise light that the metal level produced to improve the formation of image quality in photosensitive region.

Description

Optical fingerprint chip, processing method thereof and electronic equipment

Technical Field

The invention relates to the technical field of optical fingerprint identification under a screen, in particular to an optical fingerprint chip, a processing method thereof and electronic equipment.

Background

The optical fingerprint recognition can adopt the imaging principle of a CIS (CMOS Image Sensor) to perform signal acquisition on the biological fingerprint, and finally perform imaging. The resultant image is compared with the stored image, thereby identifying fingerprint information of the living organism.

With the increasing demand of fingerprint identification under the screen, the requirements on the optical fingerprint chip are higher and higher. Due to the particularity of the application field, the effective signal is very weak, and the sensitivity of the optical fingerprint chip is required to be very high, and meanwhile, unnecessary signal crosstalk (Cross Talk) is avoided.

As shown in fig. 1, the conventional optical fingerprint chip includes a silicon substrate 301', a photosensitive region 201' formed on the silicon substrate 301', and a plurality of metal layers 401' formed over the photosensitive region 201'. A photoelectric conversion device is formed on the photosensitive region 201' for converting a received optical signal into an electrical signal. The metal layers are electrically connected, and the bottom metal layer is connected with the photoelectric conversion device and used for outputting the conversion signal.

In order to prevent the metal layer 401' from affecting the light sensitivity of the light sensing region 201', the metal layer 401' is not normally distributed right above the photoelectric conversion device. The metal layers 401' form optical channels for optical signal propagation corresponding to the positions of the photoelectric conversion devices, adjacent metal layers 401' are isolated by insulating medium layers, and the optical channels are filled with light-transmitting fillers 501' such as silicon dioxide and silicon nitride. The target signal light (3) ' reflected back by the user's finger passes through the optical channel and finally reaches the photosensitive region 201'.

However, in the optical fingerprint chip, the noise light (1) ', (2)' with a large incident angle may finally reach the photosensitive region 201 'due to the reflection of the metal layer 401'. As shown in fig. 1, a part of the noise light (1) 'is incident on the sidewall of the metal layer 401', reflected by the metal layer 401', and reaches the photosensitive region 201'. A portion of the noise light (2) 'is incident on the upper surface of the metal layer 401' and is reflected between adjacent metal layers 401 'multiple times to finally reach the photosensitive region 201'. The above-mentioned noise light (1) ', (2) ' with large incident angle will cause the signal-to-noise ratio of the light received by the photosensitive area 201' to be reduced, thereby causing poor image quality.

Disclosure of Invention

In view of the above, embodiments of the present invention provide an optical fingerprint chip, a processing method thereof, and an electronic device, which can better solve the above problems.

In order to achieve the above object, the present invention provides the following technical solutions.

An optical fingerprint chip comprising:

a substrate;

a photosensitive region disposed on the substrate, the photosensitive region including a photoelectric conversion device;

a plurality of metal layer units arranged above the substrate, wherein one metal layer unit comprises a plurality of metal layers which are arranged in a direction perpendicular to the substrate with gaps, and an optical channel corresponding to at least one photoelectric conversion device is formed between adjacent metal layer units, so that incident light can reach the photoelectric conversion device through the optical channel;

and the shielding layer is arranged in the optical channel and shields at least part of the side of the metal layer unit so that the incident light cannot enter a gap between adjacent metal layers.

Preferably, the shielding layer is a light absorbing layer or a light isolating layer, and the light absorbing layer covers the whole side of the metal layer unit.

Preferably, the area of the light passage cross section of the light channel is constant along the direction perpendicular to the substrate.

Preferably, the surface of the shielding layer, which faces away from the metal layer unit shielded by the shielding layer, is perpendicular to the substrate.

Preferably, in a direction perpendicular to the substrate, an area of a light-passing cross section of the light channel gradually decreases from one end far away from the substrate to one end close to the substrate.

Preferably, one surface of the shielding layer, which faces away from the metal layer unit shielded by the shielding layer, is gradually away from the metal layer unit shielded by the shielding layer from one end away from the substrate to one end close to the substrate.

Preferably, one surface of the shielding layer, which faces away from the metal layer unit shielded by the shielding layer, is planar, or is arc-shaped in a vertical plane.

Preferably, the shielding layer is annular and is sleeved on the circumferential direction of the metal layer unit.

Preferably, the photosensitive regions are multiple, a spacing region is arranged between adjacent photosensitive regions, and the metal layer unit is located between adjacent photosensitive regions.

Preferably, a first light-transmitting material is arranged in the light channel between the adjacent shielding layers; and a second light-transmitting material is arranged between the adjacent metal layers of the metal layer unit.

An electronic device, comprising:

the display screen is provided with a fingerprint identification area and is used for being contacted by a target organism;

an excitation light source for emitting probe light toward the target organism;

the optical fingerprint chip is arranged at a position corresponding to the fingerprint identification area under the display screen, and collects the target fingerprint optical signal reflected from the fingerprint identification area.

A processing method of an optical fingerprint chip comprises the following steps:

processing and forming a photosensitive area comprising a photoelectric conversion device on a substrate;

processing and forming a plurality of metal layer units in the second light-transmitting material above the substrate, wherein one metal layer unit comprises a plurality of metal layers which are arranged in a direction perpendicular to the substrate with gaps, an optical channel corresponding to at least one photoelectric conversion device is formed between every two adjacent metal layer units, and the second light-transmitting material is arranged between every two adjacent metal layers;

removing the second light-transmitting material in the optical channel formed between the adjacent metal layer units through an etching process;

after the second light-transmitting material in the light channel is removed, filling a light absorption layer in the light channel, wherein the shielding layer shields at least part of the side of the metal layer unit, so that the incident light cannot enter a gap between adjacent metal layers;

and filling a first light-transmitting material in the light channel between the adjacent shielding layers.

By means of the technical scheme, the invention has the beneficial effects that:

when the optical fingerprint chip emits the noise light with a large incident angle, the noise light with a large incident angle is emitted to the space between the adjacent metal layers through the optical channel, and the shielding layer is arranged on the optical channel and shields at least part of the side of the metal layer unit, so that the noise light with a large incident angle is shielded or reflected by the shielding layer and cannot enter the space between the adjacent metal layers, and the noise light is reflected on the upper surface and the lower surface of the metal layer and then reaches the photosensitive area of the adjacent optical channel. The great noise light of above-mentioned incident angle will unable signal to noise ratio that leads to the light that the photosensitive area received reduces, and then can't cause the reduction of formation of image quality, so, this application can avoid the photosensitive area to receive the noise light through reflection between the adjacent metal level to improve the formation of image quality of photosensitive area.

Specific embodiments of the present invention are disclosed in detail with reference to the following description and drawings, indicating the manner in which the principles of the invention may be employed. It should be understood that the embodiments of the invention are not so limited in scope. Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments, in combination with or instead of the features of the other embodiments.

Drawings

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. In addition, the shapes, the proportional sizes, and the like of the respective members in the drawings are merely schematic for facilitating the understanding of the present invention, and do not specifically limit the shapes, the proportional sizes, and the like of the respective members of the present invention. Those skilled in the art, having the benefit of the teachings of this invention, may effect this invention by selecting various possible shapes and proportional dimensions as appropriate.

FIG. 1 is a schematic diagram of an optical fingerprint chip according to an embodiment known in the art;

FIG. 2 is a schematic structural diagram of an optical fingerprint chip according to a first embodiment of the present invention;

fig. 3 is a schematic structural diagram of an optical fingerprint chip according to a second embodiment of the invention.

Reference numbers to the above figures:

101. a shielding layer; 201. a light sensing area; 301. a substrate; 40. a metal layer unit; 401. a metal layer; 501. a first light-transmitting material; 601. a second light transmissive material.

Detailed Description

The details of the present invention can be more clearly understood in conjunction with the accompanying drawings and the description of the embodiments of the present invention. However, the specific embodiments of the present invention described herein are for the purpose of illustration only and are not to be construed as limiting the invention in any way. Any possible variations based on the present invention may be conceived by the skilled person in the light of the teachings of the present invention, and these should be considered to fall within the scope of the present invention. It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "mounted," "connected," and "connected" are to be construed broadly and may include, for example, mechanical or electrical connections, communications between two elements, direct connections, and indirect connections through intervening media, as well as the detailed meanings of the terms as understood by those skilled in the art. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In order to absorb noise light generated by the metal layer 401 to improve the imaging quality of the photosensitive region 201, an optical fingerprint chip is provided in the present application, where fig. 2 is a schematic structural diagram of an optical fingerprint chip according to a first embodiment of the present invention, and fig. 3 is a schematic structural diagram of an optical fingerprint chip according to a second embodiment of the present invention, and as shown in fig. 2 and fig. 3, the optical fingerprint chip may include: a substrate 301; a photosensitive region 201 disposed on the substrate 301, the photosensitive region 201 including a photoelectric conversion device; a plurality of metal layer units 40 disposed above the substrate 301, one metal layer unit 40 including a plurality of metal layers 401, the plurality of metal layers 401 being arranged with gaps in a direction perpendicular to the substrate 301, and an optical channel corresponding to at least one of the photoelectric conversion devices being formed between adjacent metal layer units 40, so that incident light reaches the photoelectric conversion device through the optical channel; and the shielding layer 101 is arranged in the light channel, and the shielding layer 101 shields at least part of the side of the metal layer unit 40 so that the incident light cannot enter a gap between the adjacent metal layers 401.

When the optical fingerprint chip in the present application enters the noise light (1), (2) with large incident angles, and the noise light with large incident angles is emitted to the space between the adjacent metal layers 401 through the optical channel, because the optical channel is provided with the shielding layer 101, the shielding layer 101 shields at least part of the side of the metal layer unit 40, therefore, the noise light with large incident angles is shielded or reflected by the shielding layer 101, and cannot enter the space between the adjacent metal layers 401, generate reflection on the upper and lower surfaces of the metal layers 401, and then reach the photosensitive area 201 of the adjacent optical channel. The above noise light with a large incident angle cannot result in the reduction of the signal-to-noise ratio of the light received by the photosensitive region 201, and further cannot cause the reduction of the imaging quality, so that the photosensitive region 201 can be prevented from receiving the noise light reflected between the adjacent metal layers 401, and the imaging quality of the photosensitive region 201 is improved.

In order to better understand the optical fingerprint chip of the present application, it will be further explained and illustrated below. As shown in fig. 2 and 3, the optical fingerprint chip includes: a substrate 301, a photoelectric conversion device, a metal layer unit 40, and a shielding layer 101. Wherein the substrate 301 extends in a horizontal direction, having opposite upper and lower surfaces. The substrate 301 may be used to fixedly dispose a photoelectric conversion device on one surface, for example, an upper surface thereof, while disposing a metal layer unit 40, a shielding layer 101, and the like, which connect the photoelectric conversion device, on the upper surface thereof. The substrate 301 serves as a support as well as an insulation. As a practical matter, the substrate 301 is typically a wafer or a silicon substrate.

As shown in fig. 2 and fig. 3, a photosensitive region 201 is disposed on the substrate 301, and specifically, the photosensitive region 201 is disposed on the upper surface of the substrate 301, and the number of the photosensitive regions 201 may be multiple. In general. The photosensitive regions 201 are arranged in an array, that is, a plurality of photosensitive regions 201 are arranged in the horizontal direction of the paper surface, and a spacing area is arranged between adjacent photosensitive regions 201; there are also a plurality of photosensitive regions 201 in the direction perpendicular to the paper surface, and there are also spacing regions between adjacent photosensitive regions 201. Each photosensitive region 201 includes a photoelectric conversion device, which may be generally plural. It is common that the photoelectric conversion element includes a Diode (PD). It is understood that one photoelectric conversion device corresponds to one photosensitive pixel.

As shown in fig. 2 and 3, a plurality of metal layer units 40 are disposed above a substrate 301, one of the metal layer units 40 includes a plurality of metal layers 401, and the plurality of metal layers 401 are arranged with gaps in a direction perpendicular to the substrate 301. The metal layer 401 is a metal wiring connected to the photosensitive pixel, and is used for processing or leading out an electric signal output from the photoelectric conversion device. For the photo detection array manufactured by semiconductor process, the metal layer 401 is the wiring of the photo detection circuit in the optical fingerprint chip implemented by multilayer metal. It can be understood that the metal layer 401 is not distributed right above the photosensitive portion of the photoelectric conversion device under the normal distribution condition, so as to avoid the influence of the metal layer 401 on the photosensitive portion of the photoelectric conversion device. Therefore, a light channel corresponding to at least one of the photoelectric conversion devices is formed between adjacent metal layer units 40, so that incident light reaches the photoelectric conversion device through the light channel.

As shown in fig. 2 and 3, a filling medium is disposed between adjacent metal layers 401 of the metal layer unit 40, so as to support the metal layers 401. The filling medium is an insulating material to prevent conduction between adjacent metal layers 401. The filling medium may be made of a second light-transmitting material 601, for example, silicon dioxide, silicon nitride, light-transmitting organic material, or the like. Of course, a filling medium may be disposed between the metal layer unit 40 and the substrate 301 to support the metal layer unit 40. The filling medium is also typically an insulating material, and may be made of a second light-transmitting material 601 as appropriate. In other possible embodiments, the filling medium may not be an insulating material, and it is only necessary that the filling medium does not contact the photoelectric conversion devices of the photosensitive region 201.

As shown in fig. 2 and 3, the metal layers 401 in the metal layer unit 40 may be electrically connected to the metal layer 401 at the bottom layer in the metal layer unit 40 through conductive vias, which are formed in the filling medium, to connect with the photoelectric conversion device. The conductive via may be understood as a via in which a conductive substance is present to achieve electrical communication between adjacent metal layers 401 and between the metal layers 401 and the photoelectric conversion device.

As shown in fig. 2 and 3, the shielding layer 101 is disposed in the light channel, and the shielding layer 101 shields at least a part of the side of the metal layer unit 40, so that the incident light cannot enter the gap between the adjacent metal layers 401. Specifically, the blocking layer 101 may be located at a side of the gap between adjacent metal layers 401, so that noise light with a large angle of incidence in the target signal light reflected by the finger of the user in the optical channel at the side can be prevented from being emitted to between adjacent metal layers 401, and thus emission is generated between the adjacent metal layers 401 on the upper and lower surfaces of the metal layers 401 to be emitted to another adjacent optical channel, and further to the photosensitive region 201 corresponding to the another optical channel. Therefore, the noise light with the large incident angle cannot cause the reduction of the signal-to-noise ratio of the light received by the photosensitive area 201, and further cannot cause the reduction of the imaging quality, so that the incident light which originally emits to the gap between the adjacent metal layers 401 can be blocked or reflected, the photosensitive area 201 is prevented from receiving the noise light reflected between the adjacent metal layers 401, and the imaging quality of the photosensitive area 201 is improved.

As a practical matter, one side of the shielding layer 101 close to the metal layer 401 may be closely attached to the upper and lower metal layers 401, so as to prevent the target signal light reflected by the finger of the user from entering through the gap between the shielding layer 101 and the metal layer 401 and finally possibly to the surrounding photosensitive area 201, thereby reducing the imaging quality of the photosensitive area 201.

As a practical matter, the shielding layer 101 may shield all sides of the metal layer unit 40, so that incident light rays that are originally directed to the side wall of the metal layer 401 may be totally blocked or reflected.

As a practical matter, the shielding layer 101 may be made of a material capable of shielding light, such as a non-transparent organic material, a metal material, or the like.

In the above embodiments, the shielding layer 101 may be a light absorbing layer or a light shielding layer, which can absorb or shield all incident light rays toward itself. When the shielding layer 101 is a light absorbing layer, no reflection occurs, so that the reflected light is prevented from being emitted to the photosensitive area 201, which results in a decrease in the signal-to-noise ratio of light received by the photosensitive area 201, and further, the image quality cannot be reduced. The light absorbing layer may be made of a non-transparent organic material having an absorbing effect on light. Preferably, the light absorbing layer covers the entire side of the metal layer unit 40, so that it is also avoided that noise light with a large incident angle in the target signal light reflected by the finger of the user in the light channel is reflected by the side wall of the metal layer 401, and the reflected light is reflected to the photosensitive area 201, which results in a decrease in the signal-to-noise ratio of the light received by the photosensitive area 201 and thus cannot cause a decrease in the image quality. The light absorption layer effectively solves the interference of large-angle light and scattered light, and effectively improves the application scene and performance of the optical fingerprint chip.

When the shielding layer 101 is a light-blocking layer, the light-blocking layer may preferably be made of a metal material, so that the light-blocking layer is easily formed by processing.

As shown in fig. 2, it is feasible that the area of the light passage cross section of the light channel is constant in the direction perpendicular to the substrate 301. By the above method, effective light with a small incident angle in the target signal light reflected by the finger of the user can pass through the light channel to a large extent and finally irradiate to the photosensitive area 201 corresponding to the light channel, and the photoelectric conversion device of the photosensitive area 201 can receive the effective light, so that the imaging quality of the photosensitive area 201 is further improved. In this embodiment, the surface of the shielding layer 101 facing away from the metal layer unit 40 shielded by itself is perpendicular to the substrate 301, so as to ensure that the area of the light-passing cross section of the channel is constant in the direction perpendicular to the substrate 301.

As shown in fig. 3, it is feasible that, in a direction perpendicular to the substrate 301, the area of the light-passing cross section of the light channel gradually decreases from one end far away from the substrate 301 to one end close to the substrate 301. By the above method, when noise light with a large incident angle in the target signal light reflected by the finger of the user is incident on the shielding layer 101, the shielding layer 101 can reflect the noise light to a direction away from the photosensitive area 201 as far as possible. The larger the area of the light passage cross section of the light channel is gradually reduced from the end far away from the substrate 301 to the end near the substrate 301, the larger the incident angle of the noise light can be reflected by the shielding layer 101 to the direction far away from the light sensing region 201. In this embodiment, a surface of the shielding layer 101 facing away from the metal layer unit 40 shielded by itself may gradually be away from the metal layer unit 40 shielded by itself from an end far from the substrate 301 to an end close to the substrate 301. For example, a surface of the shielding layer 101 facing away from the metal layer unit 40 shielded by itself may be planar, or may be in an arc shape in a vertical plane, and the arc shape may be a concave arc shape or a convex arc shape.

Since the metal layer 401 is a wiring of the photodetection circuit in the optical fingerprint chip implemented by multiple layers of metal, in order to avoid the influence of the metal layer 401 on the photosensitivity of the photoelectric conversion device, a spacing region is provided between adjacent photosensitive regions 201, and the metal layer unit 40 is located between adjacent photosensitive regions 201. The space therebetween may be understood as all regions on the perpendicular bisector between the adjacent photosensitive regions 201.

Generally, the metal layer 401 has a certain length, and as shown in fig. 2 and fig. 3, the metal layer 401 at least extends in a direction perpendicular to the paper surface, and may span the plurality of photosensitive regions 201, may further extend in a horizontal direction, and the like, and further spans the plurality of photosensitive regions 201. Therefore, the whole metal layer unit 40 has a circle of side in the circumferential direction, and in order to avoid incident light from entering a gap between adjacent metal layers 401 from any direction or from being emitted to a side wall of the metal layer 401 from any direction and being reflected to the photosensitive region 201, the shielding layer 101 may be annular and is sleeved on the circumferential direction of the metal layer unit 40, so that the circumferential direction of the whole metal layer unit 40 is shielded by the shielding layer 101, and the imaging quality of the photosensitive region 201 is improved to the greatest extent.

As shown in fig. 2 and 3, a first light-transmitting material 501 is disposed in the light channel between adjacent blocking layers 101, so that the incident light (the target signal light reflected by the finger of the user) can reach the photosensitive region 201 through the first light-transmitting material 501. The first light-transmitting material 501 may be silicon dioxide, silicon nitride, a light-transmitting organic substance, or the like.

There is also provided in the present application an electronic device comprising: the display screen is provided with a fingerprint identification area and is used for being contacted by a target organism; an excitation light source for emitting probe light toward the target organism; the optical fingerprint chip is arranged at a position corresponding to the fingerprint identification area under the display screen, and collects the target fingerprint optical signal reflected from the fingerprint identification area. The optical fingerprint chip can be applied to scenes including but not limited to unlocking of fingerprints under a screen, user identity authentication, access control authority acquisition and the like. More specifically, the optical fingerprint chip according to the embodiment of the present invention may be applied to electronic devices, including but not limited to mobile smart phones, tablet electronic devices, computers, GPS navigators, personal digital assistants, smart wearable devices, and other electronic devices.

The electronic device mentioned in the embodiments of the present invention may further include other necessary modules or components in order to realize the basic functions of the electronic device. Taking a mobile smart phone as an example, it may further include a communication module, a battery, and the like. It should be noted that any other necessary modules or components included in the electronic device may be used in any suitable existing configuration. For clearly and briefly explaining the technical scheme provided by the invention, the parts are not described again, and the drawings in the specification are correspondingly simplified. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended.

The electronic device may be configured with a display screen provided with a fingerprint identification area for contact by a target organism, such as a finger of a user, which may be a partial area of an upper surface of the display screen. An excitation light source for emitting probe light to the target organism may be provided below the display screen.

In some embodiments, the display screen may be a self-luminous display screen employing self-luminous units as display pixels, such as an OLED display screen or an LED display screen. Therefore, the display screen can be used as an excitation light source to emit excitation light to the target organism, and the excitation light is reflected by the target organism to form a target light signal. Such excitation light source is usually visible light, and the detection light detected by the optical fingerprint identification device is usually corresponding to visible light.

Certainly, the display screen may also be a backlight module such as an LCD display screen or other passive light emitting display screens. Such electronic devices may be provided with additional light sources located below the backlight module or at other orientations as the excitation light source. Generally, under the application of the backlight module, the light source of the electronic device equipped for the optical fingerprint identification device is an infrared light source, and the sensing pixel unit in the optical fingerprint chip arranged under the display screen correspondingly senses infrared light.

The application also provides a processing method of the optical fingerprint chip, which comprises the following steps:

a photosensitive region 201 including a photoelectric conversion device is processed on a substrate 301. The photosensitive regions 201 are generally a plurality of photosensitive regions, which are arranged in sequence in the horizontal direction and the direction perpendicular to the paper plane, and a spacing region is provided between adjacent photosensitive regions 201.

Processing and forming a plurality of metal layer units 40 in the second light-transmitting material 601 above the substrate 301, where one metal layer unit 40 includes a plurality of metal layers 401, the plurality of metal layers 401 are arranged with gaps in a direction perpendicular to the substrate 301, an optical channel corresponding to at least one photoelectric conversion device is formed between adjacent metal layer units 40, and the optical channel and the adjacent metal layers 401 are both made of the second light-transmitting material 601. The second transparent material 601 and the metal layer 401 are the back end of the semiconductor process, and the metal layer 401 is formed by metal wiring, and the second transparent material 601 is a material isolating the metal layer 401, is transparent, and may generally adopt silicon dioxide.

The second light-transmitting material 601 in the light channel formed between the adjacent metal layer units 40 is removed by an etching process. The second light-transmitting material 601 (non-metal region) in the optical channel formed between the adjacent metal layer units 40 is etched by using a semiconductor photomask process to remove, for example, ion etching or wet etching.

After the second light-transmitting material 601 in the optical channel is removed, a shielding layer 101 is filled in the optical channel, and at least part of the side of the metal layer unit 40 is shielded by the shielding layer 101, so that the incident light cannot enter a gap between adjacent metal layers 401. Preferably, the shielding layer 101 may shield the entire side of the metal layer unit 40 so that the incident light does not enter a gap between adjacent metal layers 401 or is not reflected through a sidewall of the metal layer 401. As a possibility, the shielding layer 101 may be a light absorbing layer. The masking layer 101 may be filled by spraying, spin coating, CVD/PVD, or the like.

A first light-transmitting material 501 is filled in the light channel between the adjacent shielding layers 101. The first light-transmitting material 501 can be filled by spraying, spin coating, CVD/PVD or other methods, and the first light-transmitting material 501 and the upper surface of the shielding layer 101 can be flush with each other, so that the optical fingerprint chip in the present application is obtained by processing.

The embodiments in the present specification are all described in a progressive manner, and each embodiment focuses on differences from other embodiments, and portions that are the same and similar between the embodiments may be referred to each other. The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered in the protection scope of the present invention.

Claims (12)

1. An optical fingerprint chip, comprising:

a substrate;

a photosensitive region disposed on the substrate, the photosensitive region including a photoelectric conversion device;

a plurality of metal layer units arranged above the substrate, wherein one metal layer unit comprises a plurality of metal layers which are arranged in a direction perpendicular to the substrate with gaps, and an optical channel corresponding to at least one photoelectric conversion device is formed between adjacent metal layer units, so that incident light can reach the photoelectric conversion device through the optical channel;

and the shielding layer is arranged in the optical channel and shields at least part of the side of the metal layer unit so that the incident light cannot enter a gap between adjacent metal layers.

2. The optical fingerprint chip of claim 1, wherein the blocking layer is a light absorbing layer or a light isolating layer, and the light absorbing layer or the light isolating layer covers the entire side of the metal layer unit.

3. The optical fingerprint chip of claim 1 wherein the area of the light passage cross-section of the light channel is constant along a direction perpendicular to the substrate.

4. The optical fingerprint chip of claim 3, wherein a side of the shielding layer opposite to the metal layer unit shielded by itself is perpendicular to the substrate.

5. The optical fingerprint chip of claim 1, wherein the area of the light passage cross section of the light channel in the direction perpendicular to the substrate is gradually reduced from the end away from the substrate to the end close to the substrate.

6. The optical fingerprint chip of claim 5, wherein the side of the shielding layer opposite to the metal layer unit shielded by itself is gradually away from the metal layer unit shielded by itself from the end far away from the substrate to the end close to the substrate.

7. The optical fingerprint chip of claim 6 wherein the side of the shielding layer opposite to the metal layer unit shielded by itself is planar or in an arc shape in a vertical plane.

8. The optical fingerprint chip of claim 1 wherein the shielding layer is annular and disposed around the metal layer unit.

9. The optical fingerprint chip of claim 1 wherein said photosensitive areas are plural, and there is a spacing region between adjacent said photosensitive areas, and said metal layer unit is located between adjacent said photosensitive areas.

10. The optical fingerprint chip of claim 1 wherein a first light transmissive material is disposed in the light channel between adjacent masking layers; and a second light-transmitting material is arranged between the adjacent metal layers of the metal layer unit.

11. An electronic device, comprising:

the display screen is provided with a fingerprint identification area and is used for being contacted by a target organism;

an excitation light source for emitting probe light toward the target organism;

the optical fingerprint chip according to any one of claims 1 to 10, which is disposed under the display screen at a position corresponding to a fingerprint identification area, and collects a target fingerprint light signal reflected from the fingerprint identification area.

12. A processing method of an optical fingerprint chip is characterized by comprising the following steps:

processing and forming a photosensitive area comprising a photoelectric conversion device on a substrate;

processing and forming a plurality of metal layer units in the second light-transmitting material above the substrate, wherein one metal layer unit comprises a plurality of metal layers, the plurality of metal layers are arranged in a direction perpendicular to the substrate with gaps, an optical channel corresponding to at least one photoelectric conversion device is formed between every two adjacent metal layer units, and the second light-transmitting material is arranged between every two adjacent metal layers;

removing the second light-transmitting material in the optical channel formed between the adjacent metal layer units through an etching process;

after the second light-transmitting material in the light channel is removed, filling a light absorption layer in the light channel, wherein the shielding layer shields at least part of the side of the metal layer unit, so that the incident light cannot enter a gap between adjacent metal layers;

and filling a first light-transmitting material in the light channel between the adjacent shielding layers.

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