WO2021062999A1

WO2021062999A1 - Optical sensor, optical sensing system, and method for manufacturing optical sensor

Info

Publication number: WO2021062999A1
Application number: PCT/CN2020/087524
Authority: WO
Inventors: 涂志中
Original assignee: 神盾股份有限公司
Priority date: 2019-10-03
Filing date: 2020-04-28
Publication date: 2021-04-08
Also published as: TW202115888A; CN111401333A; CN212009590U; TWM598530U

Abstract

Provided are an optical sensor, an optical sensing system, and a method for manufacturing an optical sensor. The optical sensor comprises a substrate (201), a patterned light-shielding layer (205) located on the substrate, a transparent dielectric layer (210) located on the patterned light-shielding layer and covering sensing pixels (203), and a light guide layer (214) arranged on the transparent dielectric layer, wherein the substrate comprises a plurality of sensing pixels; the patterned light-shielding layer is formed by irradiating a photomask (30) onto a light-shielding material layer (2050) through an excimer laser light source (40), and the patterned light-shielding layer includes a plurality of through holes (207), with the positions of the plurality of through holes corresponding to the positions of the sensing pixels and exposing the sensing pixels; and the light guide layer, which is arranged on the transparent dielectric layer, comprises a plurality of light guide members corresponding to the plurality of through holes, and the plurality of light guide members guide incident light to penetrate through the transparent dielectric layer to reach the sensing pixels exposed by the plurality of through holes.

Description

Optical sensor, optical sensor system and manufacturing method thereof

Technical field

The invention relates to an optical sensor, an optical sensing system and a manufacturing method thereof, in particular to an optical sensor, an optical sensing system and a manufacturing method thereof that can simplify the process and improve the product yield.

Background technique

With the trend of mobile electronic devices moving towards larger display areas and narrow bezels, integrating the fingerprint recognition device under the screen is the best way to unlock the screen. However, most of the current manufacturing methods of optical collimators are formed by semiconductor technology, and a few are formed by optical fiber technology. However, the above two methods of forming the light collimator both face the problems of low process yield and high cost.

Summary of the invention

The purpose of the present invention is to provide an optical sensor, an optical sensing system and a manufacturing method thereof to solve at least one of the above-mentioned problems.

Some embodiments of the present invention disclose an optical sensor including a substrate, a patterned light-shielding layer on the substrate, a transparent medium layer on the patterned light-shielding layer and covering sensing pixels, and a transparent medium layer disposed on the transparent medium layer A light guide layer on top. Wherein, the substrate includes a plurality of sensing pixels, and the patterned light-shielding layer is formed on a light-shielding material layer by irradiating a mask with an excimer laser light source. The patterned light-shielding layer includes a plurality of through holes, and the patterned light shielding layer includes a plurality of through holes. The position corresponds to the position of the sensing pixel and exposes the sensing pixel. The light guide layer disposed on the transparent medium layer includes a plurality of light guide members corresponding to a plurality of through holes, wherein the plurality of light guide members guide an incident light to penetrate the transparent medium layer to the sensing pixels exposed by the through holes.

In some embodiments, the sidewall of the through hole has a surface roughness of 0.15 nm or less.

In some embodiments, the patterned light-shielding layer is a polymer material with light-shielding properties.

In some embodiments, the patterned light-shielding layer has a thickness ranging from about 2 μm to 500 μm.

In some embodiments, the aspect ratio of the through hole is in the range of 5-15.

According to some embodiments of the present invention, an optical sensing system is disclosed, including a frame having a accommodating groove, an optical sensor as described above arranged in the accommodating groove, and an optical sensor arranged on the optical sensor. One display.

According to some embodiments of the present invention, a method for manufacturing an optical sensor is disclosed, including: providing a substrate, wherein the substrate includes a plurality of sensing pixels; forming a light-shielding material layer on the substrate; and providing a photomask on the substrate Above the light-shielding material layer, the photomask has a light-shielding pattern; an excimer laser light source is used to irradiate and scan the light-shield to transfer the light-shielding pattern on the photomask to the light-shielding material layer to form a A patterned light-shielding layer, wherein the patterned light-shielding layer includes a plurality of through holes, and the positions of the plurality of through holes correspond to the positions of the sensing pixels and expose the sensing pixels; a transparent medium layer is formed on the patterned light-shielding layer, and The transparent medium layer covers the sensing pixels; a light guide layer is formed on the transparent medium layer, and the light guide layer includes a plurality of light guide members corresponding to a plurality of through holes, wherein the plurality of light guide members guide an incident light to penetrate the transparent medium layer To the sensing pixels exposed by the through holes.

In some embodiments, the excimer laser light source is a linear light source.

The beneficial effect of the present invention is that according to some embodiments of the present disclosure, the optical sensor, the optical sensing system, and the manufacturing method thereof can use a high-energy excimer laser light source to directly perform one-time pattern processing on the light-shielding material layer. And it will not cause thermal damage to the light-shielding material layer, can easily and quickly obtain holes with sufficient aspect ratio and good quality (flat surface), and there is no need to use optical glue to bond the light collimating layer as in the optical fiber process. The thickness of the manufactured optical sensor is reduced, thereby reducing the overall thickness of the applied electronic device.

Description of the drawings

Figures 1 to 6 are schematic cross-sectional views showing an optical sensor at multiple intermediate stages in the process according to some embodiments of the present invention.

FIG. 7 shows a schematic cross-sectional view of an optical sensor according to another embodiment of the present invention.

FIG. 8 shows a schematic cross-sectional view of an optical sensing system according to an embodiment of the present disclosure.

The reference signs are as follows:

201: Substrate

202: Sensing pixel array

203: Sensing pixels

2050: Shading material layer

205: Patterned shading layer

207: Through hole

207s: sidewall

210: transparent medium layer

212: filter layer

214: Light Guide Layer

215: Micro lens

217: protective layer

LC: Cutting line

LU: Optical sensing unit

30: Mask

301: Shading part

302: Translucent part

30P: shading pattern

40, 40(i-1), 40(i), 40(i+1): Excimer laser light source

D1: Scan direction

500: display

F: target

F1: Convex

F2: recess

600: Optical sensing system

L1, L2: light

700: Frame

710: Containment Slot

800: battery

900: base

1000: Optical sensor module

1001: Carrier plate

1002: flexible circuit board

1003: wire bonding

1006: Sealing layer

T: thickness

h: depth

d: Aperture

Detailed ways

The invention provides an optical sensor, an optical sensor system and a manufacturing method thereof.

Please refer to FIG. 1 to FIG. 6, which show a schematic cross-sectional view of an optical sensor at various intermediate stages in the process.

As shown in FIG. 1, a substrate 201 is provided, and the substrate 201 includes, for example, a plurality of sensing pixels 203 arranged in a sensing pixel array 202. The substrate 201 may be a semiconductor substrate, such as a silicon substrate. In addition, the aforementioned semiconductor substrate may also be an elemental semiconductor or a compound semiconductor.

Furthermore, the plurality of sensing pixels 203 included in the substrate 201 may be connected to a signal processing circuit (not shown). Each sensing pixel 203 may include one or more photodetectors. The light detector may be a complementary metal-oxide-semiconductor (CMOS) image sensor. In some other embodiments, the photodetector may also include a charged coupling device (CCD) sensor, an active sensor, a passive sensor, other suitable sensors, or a combination of the foregoing. The sensing pixel 203 can convert the received light signal into an electronic signal through a photodetector, and process the above-mentioned electronic signal through a signal processing circuit.

2, a light-shielding material layer 2050 is formed on the substrate 201. The light-shielding material layer 2050 covers the sensing pixels 203 included in the sensing pixel array 202. The light-shielding material layer contains a light-shielding material having a light transmittance of less than 1% or less in the wavelength range of 1200 nanometers or less.

The light-shielding material layer 2050 includes a polymer material having light-shielding properties, for example, a resin material having light-shielding properties. In addition, the light-shielding material layer 2050 may be a polymer material containing pigments or dyes, so that the light-shielding material layer 2050 has light-shielding properties. For example, the light-shielding material layer 2050 may contain black pigments such as carbon black or black particles, or resin materials of other pigments. In some embodiments, the light-shielding material layer 2050 includes polyester, polyimide, polystyrene, polycarbonate, epoxy, benzocyclobutene (BCB), and Xylene, acrylic, polybenzoxazole (PBO), other suitable materials, or a combination of the above. Furthermore, in some embodiments, the light-shielding material layer 2050 can be formed on the substrate 201 by, for example, spin-coating, chemical vapor deposition (CVD), other suitable methods, or a combination of the above. In addition, according to the characteristics of the polymer material selected for the light-shielding material layer 2050, after the light-shielding material layer 2050 is formed on the substrate 201, a curing process of heating or lighting may also be included.

According to an embodiment of the present disclosure, the light-shielding material layer 2050 has a thickness T ranging from about 2 μm to about 500 μm. In some embodiments, the light-shielding material layer 2050 has a thickness T ranging from about 50 μm to about 500 μm. In some embodiments, the light-shielding material layer 2050 has a thickness T ranging from about 50 μm to about 200 μm. In some embodiments, the light-shielding material layer 2050 has a thickness T ranging from about 100 μm to about 200 μm.

3, a photomask 30 is provided above the light-shielding material layer 2050, and the photomask 30 has a predetermined light-shielding pattern. In some embodiments, the photomask 30 includes a plurality of light-shielding parts 301 and a plurality of light-transmitting parts 302 appropriately arranged to form a light-shielding pattern 30P.

As shown in FIGS. 3 to 4, after the mask 30 is provided on the light-shielding material layer 2050, an excimer laser light source (excimer laser light source) 40 is used to illuminate and scan the mask 30, for example, as shown in FIG. Scan the photomask 30 in the direction D1 to transfer the light-shielding pattern 30P on the photomask 30 to the light-shielding material layer 2050 to form a patterned light-shielding layer 205.

According to the embodiment of the present disclosure, the size of the sensing pixel, the thickness of the patterned light-shielding layer 205 and other parameters affecting optical sensing in the application device can be adjusted to adjust the aperture of the through hole 207 to be formed. In some embodiments, the aperture of the through hole 207 of the patterned light shielding layer 205 is in the range of 1 μm to 35 μm, but the present disclosure is not limited thereto.

Furthermore, the depth h of the through hole 207 is approximately equal to the thickness T of the patterned light shielding layer 205. In some embodiments, the depth h of the through hole 207 is in the range of about 5 μm to about 500 μm, or in the range of 50 μm to about 500 μm, or in the range of 50 μm to about 200 μm, or in the range of 100 μm to about 200 μm.

According to some embodiments of the present disclosure, since a polymer light-shielding material layer can be formed on the substrate 201 and used with an excimer laser light source to transfer the light-shielding pattern, a through hole 207 with a high aspect ratio can be formed at the light-shielding material layer 2050. . In some embodiments, the aspect ratio of the through hole 207 is in the range of 5-15. Taking the thickness of the patterned light-shielding layer 205 as an example, when the aperture d of the through hole 207 is 10 μm, the aspect ratio h/d of the through hole 207 is 10, and the aperture d of the through hole 207 is 6.67 μm. The aspect ratio is 15.

In FIG. 3, the excimer laser light source 40 scans the mask 30 along the scanning direction D1 as shown in the figure. Among them, the excimer laser light source 40(i-1) represents the (i-1)th pattern that the excimer laser light source travels to the mask 30 during scanning, such as a shading part 301, so the lower part corresponds to the shading part 301 The portion of the light-shielding material layer 2050 is retained on the substrate 201. The excimer laser light source 40(i) represents the (i)th pattern of the excimer laser light source traveling to the mask 30 during scanning, such as a light-transmitting part 302, so the excimer laser light source 40(i) is cut out from the bottom Corresponding to the portion of the light-shielding material layer 2050 of the light-transmitting portion 302, a through hole 207 is formed. Similarly, the excimer laser light source 40(i+1) represents the (i+1)th pattern that the excimer laser light source travels to the mask 30 during scanning, such as the next shading part 301, so the corresponding shading material below Part of the layer 2050 is retained on the substrate 201.

In some embodiments, the excimer laser is a high-power deep ultraviolet light that is excited by an electric discharge after mixing an inert gas and a more active halogen. Excimer lasers are available in ArF (193nm), KrF (248nm), XeCl (308nm), XeF (351nm) and other types due to different waves. In some embodiments, the light source of the excimer laser is ArF or KrF laser, where ArF laser is suitable for processing PMMA, and KrF is suitable for processing polyimide and polycarbonate. In some embodiments, the excimer laser is deep ultraviolet light with a wavelength of 200-300 nm, the exposure depth is hundreds of micrometers (μm), and the aspect ratio is 5-15.

In addition, in some embodiments, the excimer laser light source 40 includes a plurality of laser heads (not shown), for example, the plurality of laser heads are arranged to form a line light source, and the line light source is aligned along the direction D1 as shown in FIG. The mask 30 performs scanning. As shown in FIG. 3, in an example, a plurality of laser heads are arranged along the Z direction to form a line light source, and scan the mask 30 along the −X direction. Therefore, according to the manufacturing method proposed in some embodiments of the present disclosure, the excimer laser light source 40 including multiple laser heads can scan a large area substrate to complete the transfer of the light shielding pattern 30P in an appropriate time, which is suitable for application Fabrication of optical sensors on large-area substrates.

4, the plurality of through holes 207 of the patterned light shielding layer 205 formed on the substrate 201 correspond to the positions of the plurality of sensing pixels of the sensing pixel array 202, and the sensing pixels 203 are exposed. According to some embodiments of the present invention, by forming a patterned light-shielding layer 205 on the substrate 201, it is possible to prevent the sensing pixel array 202 from receiving unwanted light, and to prevent crosstalk caused by the light incident on the optical sensor. , Thereby improving the performance of the optical sensor.

Because the excimer laser light source can remove the material in a very small explosive manner at low temperature and in a very short time, it will not cause thermal damage to the material layer. From the above results of drilling with different lasers, it can be clearly seen that the holes processed by the excimer laser light source are hardly affected by the thermal effect, and a relatively smooth sidewall surface is obtained. Therefore, the embodiment of the present disclosure uses the excimer laser as the light source to improve the quality of the through holes.

Therefore, the through hole 207 formed by the method proposed in the above embodiment has a very smooth sidewall surface, and the edge of the opening is also very flat. In some embodiments, the sidewall 207s of the formed through hole 207 has a surface roughness of 0.15 nm or less or 0.10 nm or less.

5, a transparent medium layer 210 can be formed on the patterned light-shielding layer 205, and the transparent medium layer 210 covers the sensing pixels 203 exposed from the through holes 207 of the patterned light-shielding layer 205. The transparent medium layer 210 may include a UV-curable material, a thermosetting material, or a combination of the above.

5 again, a light guide layer 214 is formed on the transparent medium layer 210, and the light guide layer 214 includes a plurality of light guide members, such as microlenses 215, the plurality of microlenses 215 correspond to the through holes 207 of the patterned light shielding layer 205 . A plurality of light guides (such as microlenses 215) guide an incident light to pass through the transparent medium layer 210 to the sensing pixels 203 exposed by the plurality of through holes 207.

In some embodiments, the material of the light guide layer 214 (for example, a microlens layer) may include a transparent photocurable material or a thermal curing material, and the formed microlens layer may undergo a patterning process to control the radius of curvature of the microlens 215 .

6, a protective layer 217 is covered on the light guide layer 214 (including a plurality of microlenses 215) and the patterned light shielding layer 205. In some embodiments, the protective layer 217 may be formed of silicon dioxide, and may be formed by plasma-enhanced chemical vapor deposition (plasma-enhanced CVD, PECVD), remote plasma-enhanced chemical vapor deposition (remote plasma-enhanced CVD, RPECVD). ), other similar methods or a combination of the above to deposit silicon dioxide on the microlenses 215 and the patterned light-shielding layer 205. The protective layer 217 can effectively protect the microlens 215 to prevent the microlens 215 from being damaged during the subsequent packaging process.

FIG. 7 shows a schematic cross-sectional view of an optical sensor according to some other embodiments of the present invention. As shown in FIG. 7, a filter layer 212 is disposed between the transparent medium layer 210 and the patterned light-shielding layer 205 and/or the microlens 215, and the microlens 215 is formed after the filter layer 212 is formed. In some embodiments, the filter layer 212 may be an infrared cut filter (ICF). Visible light has high transmittance to the infrared filter layer, and infrared light has high reflectivity to it. The filter layer 212 can correct the color shift of the optical sensor and reduce the interference of infrared rays.

Referring to FIG. 8, in some embodiments, the optical sensing system 600 includes an optical sensor 200, a display 500, a frame 700, a battery 800 and a base 900. For the components of the optical sensor 200, please refer to the content of the above-mentioned embodiment. The base 900 may be, for example, a part of the housing of an electronic device. The battery 800 can be disposed on the base 900. The frame 700 can be disposed above the battery 800 and has a receiving groove 710, but the embodiment of the present disclosure is not limited to this. In some other embodiments, the frame 700 may not have the accommodating groove 710, depending on actual requirements.

As shown in FIG. 8, an optical sensor 200 for sensing an image of a target F can be disposed on the frame 700. The optical sensor 200 can be disposed in the receiving groove 710 of the frame 700 and located on a bottom surface of the receiving groove 710. The display 500 can be arranged above the optical sensor 200 for displaying information. The target F can be located on or above the display 500. The optical sensor 200 can sense and recognize the contour features of the target F (for example, fingerprint features of a finger), and the battery 800 can supply power to the optical sensor 200 and the display 500 to maintain the operation of the electronic device. Furthermore, the optical sensor 200 can be (but not limited to) be disposed in an optical sensor module 1000 including a carrier board 1001, a flexible circuit board 1002, a bonding wire 1003, and a sealing glue layer 1006, wherein the optical sensor The device 200 and the flexible circuit board 1002 are electrically connected by a bonding wire 1003.

At present, most optical collimators are manufactured by using semiconductor technology, and a few are formed by optical fiber technology. When the optical collimator is formed by a semiconductor process, due to the ability of the etching photolithography process, it is impossible to directly etch holes with sufficient aspect ratio in a thick film layer, so it is necessary to deposit multiple film layers with holes. A stacking method is used to construct holes with a required aspect ratio. However, this process is time-consuming, and the stacked holes need to have precise positions, and the process yield needs to be improved. In addition, in the current method of forming an optical collimator using an optical fiber process, the optical fiber glass needs to be sintered, the process is not easy, and the optical fiber glass is easily broken when the thickness is less than 200μm, for example, not only is not suitable for the production of large-area substrates, but also requires Optical adhesive (optically clear adhesive, OCA) is used to bond the fiber glass on the substrate with sensing pixels, and the optical adhesive increases the thickness of the entire optical sensor. For example, the thickness of the optical fiber glass is about 200 μm to 250 μm, the thickness of the optical glue is about 50 μm, and the total thickness of the optical fiber collimator is about 250 μm to 300 μm.

According to the optical sensors, optical sensing systems and manufacturing methods proposed in some embodiments of the present disclosure, a high-energy excimer laser light source can be used to directly perform one-time pattern processing on the light-shielding material layer without causing any damage to the light-shielding material layer. Causes heat damage, can easily and quickly obtain holes with sufficient aspect ratio and good quality (flat surface), and there is no need to use optical glue to bond the light collimating layer as in the optical fiber process, which can reduce the number of optical sensors. , Thereby reducing the overall thickness of the applied electronic device.

Claims

An optical sensor, including:

A substrate including a plurality of sensing pixels;

A patterned light-shielding layer is disposed on the substrate. The patterned light-shielding layer is formed on a light-shielding material layer by irradiating a mask with an excimer laser light source. The patterned light-shielding layer includes a plurality of through holes and a plurality of through holes. The positions of each of the through holes correspond to the positions of a plurality of the sensing pixels and expose a plurality of the sensing pixels;

A transparent medium layer located on the patterned light-shielding layer and covering a plurality of said sensing pixels; and

A light guide layer is arranged on the transparent medium layer, and the light guide layer includes a plurality of light guide members corresponding to a plurality of said through holes, wherein a plurality of said light guide members guide an incident light to penetrate the transparent medium layer To the plurality of sensing pixels exposed by the plurality of through holes.
The optical sensor of claim 1, wherein the sidewalls of the plurality of through holes have a surface roughness of 0.15 nm or less.
8. The optical sensor of claim 1, wherein the patterned light-shielding layer is a polymer material with light-shielding properties.
The optical sensor of claim 1, wherein the patterned light-shielding layer comprises polyester, polyimide, polystyrene, polycarbonate, epoxy resin, benzocyclobutene, parylene, Acrylic, polybenzoxazole or a combination of the foregoing.
8. The optical sensor of claim 1, wherein the patterned light-shielding layer is made of carbon black, black pigment with black particles, or resin material containing other pigments.
8. The optical sensor of claim 1, wherein the patterned light-shielding layer has a thickness ranging from 2 μm to 500 μm.
8. The optical sensor of claim 1, wherein the aspect ratio of the plurality of through holes is in the range of 5-15.
An optical sensing system, including:

A frame with a accommodating slot;

7. The optical sensor of any one of claims 1-7, which is disposed in the accommodating groove; and

A display is arranged on the optical sensor.
A manufacturing method of an optical sensor includes:

Providing a substrate, wherein the substrate includes a plurality of sensing pixels;

Forming a light-shielding material layer on the substrate;

Providing a light shield above the light shielding material layer, the light shield having a light shielding pattern;

Irradiating and scanning the mask with an excimer laser light source to transfer the shading pattern on the mask to the shading material layer to form a patterned shading layer, wherein the patterned shading layer includes a plurality of through holes, And the positions of the plurality of through holes correspond to the positions of the plurality of sensing pixels and expose the plurality of sensing pixels;

Forming a transparent medium layer on the patterned light-shielding layer, and the transparent medium layer covers a plurality of the sensing pixels; and

A light guide layer is formed on the transparent medium layer, and the light guide layer includes a plurality of light guide members corresponding to a plurality of through holes, wherein the plurality of light guide members guide an incident light to penetrate the transparent medium layer at most A plurality of the sensing pixels exposed by the through holes.
9. The method of manufacturing an optical sensor according to claim 9, wherein the excimer laser light source is a line light source.