TWM602656U - Optical biometrics sensor and electronic apparatus using the same - Google Patents

Abstract

An optical biometrics sensor and an electronic apparatus using the same are disclosed. The optical biometrics sensor includes an optical sensor chip, an optical structure and a metal IR filter layer. The optical sensor chip includes a substrate and one or multiple sensing pixels formed on the substrate. The optical structure is disposed above the one or multiple sensing pixels. The metal IR filter layer is disposed on a surface of the optical structure. The one or multiple sensing pixels sense an optical image of an object located above the optical structure through the optical structure and the metal IR filter layer, which blocks environment infrared light around the object from entering the one or multiple sensing pixels, and has a thickness ranging from 1 to 0.1 μm.

Description

Optical biometric sensor and electronic equipment using the same

The present invention relates to an optical biometric sensor and electronic equipment using the same, and particularly relates to an optical biometric sensor with a thin metal IR filter layer and electronic equipment using the optical biometric sensor.

Today's mobile electronic devices (such as mobile phones, tablet computers, laptops, etc.) are usually equipped with user biometric systems, including different technologies such as fingerprints, face shapes, iris, etc., to protect personal data security, such as mobile phones Or smart watches and other portable devices also have the function of mobile payment, which has become a standard function for user biometrics, and the development of mobile phones and other portable devices is toward full screen (or ultra-narrow bezel) The trend of the traditional capacitive fingerprint button can no longer be used, and the evolution of a new miniaturized optical imaging device (very similar to the traditional camera module, with complementary metal-oxide semiconductor (CMOS) Image Sensor (CIS for short) sensing components and optical lens modules). The miniaturized optical imaging device is placed at the bottom of the screen (can be called under the screen), through the screen part of the light (especially organic light emitting diode (Organic Light Emitting Diode, OLED) screen), can capture the press on the top of the screen The image of the object, especially the fingerprint image, can be called Fingerprint On Display (FOD).

As shown in FIG. 1, in the current under-screen optical fingerprint sensor module 300, in order to solve the problem of using outdoor sunlight, an optical-mechanical structure 320 is generally arranged above the fingerprint sensor chip 310, and then the optical-mechanical structure An infrared (IR) filter layer 330 is additionally attached to the 320. The IR filter layer 330 is usually a glass substrate 332 with a thickness of 200 micrometers (μm) or more, and an IR with a multilayer structure is formed on the glass substrate 332. The filter film 334 is made. However, disposing the IR filter layer 330 under the display screen prevents the thickness of the mobile device from being effectively reduced.

To reduce the thickness of the mobile device, the limited space under the screen inevitably limits the thickness of the IR filter layer. Therefore, as shown in FIG. 2, the fingerprint sensor chip 310 can be directly used as a substrate, and an IR filter film 334 with a multilayer structure can be directly formed on the surface of the fingerprint sensor chip 310 to block IR and reduce the optical fingerprint sensor pattern. The thickness of the group 300. The current IR filter film 334 uses materials with different high and low refractive indices, such as silicon dioxide (SiO ₂ ) and titanium dioxide (TiO ₂ ), which are formed in a multi-layer staggered stacking manner. The IR filter film manufactured in this way The thickness of 334 is about 5 to 6 μm. Although the thickness of the optical fingerprint sensing module 300 can be reduced compared to FIG. 1, such a thickness is still too thick, which will cause stress to the fingerprint sensing chip 310. In addition, spin-coating photoresist or depositing a dielectric layer on the IR filter film 334 with etching and other methods can easily cause uneven structures on the edge of the IR filter film 334, resulting in uneven edge images and production yield. The problem is not high.

As shown in FIGS. 3 and 2, the width of the distribution area S2 of the IR filter film 334 with a thickness of 5 to 6 μm is the same as the width of the fingerprint sensing area S1 of the fingerprint sensor chip 310, which is likely to cause edges of the optical mechanism 320 The problem of unevenness, resulting in uneven edge images. For example, based on the research and observation of the creator of this case, the background image sensed without a finger and the fingerprint image sensed with a finger have inverted U-shaped perimeters on the upper, left and right sides The area has uneven image. These uneven shapes The problem is caused by the IR filter film 334 in the opto-mechanical structure 320. As for the lower area of the fingerprint image, there is no uneven image. This is because the lower area of the fingerprint sensing area S1 is covered by the distribution area S2 of the IR filter film 334, which is the IR filter film 334 extends down to the area S3, while the fingerprint sensing area S1 does not extend to the area S3.

As shown in Figures 4 and 2, although the distribution area S2 of the IR filter film 334 can be increased to make its area larger than the fingerprint sensing area S1 to solve the problem of uneven edge images, this approach will cause the chip The problem of increased area and increased cost.

Therefore, one object of the present invention is to provide an optical biometric sensor and electronic equipment using it, which is used to solve the problem of uneven edge image, reduce the thickness of the optical biometric sensor, and eliminate the metal IR filter layer For the stress problem caused by the optical sensor chip.

To achieve the above objective, the present invention provides an optical biometric sensor, which at least includes an optical sensor chip, an optomechanical structure, and a metal IR filter layer. The optical sensing chip at least includes a substrate and one or more sensing pixels, which are formed on the substrate. The optomechanical structure is located above the sensing pixels. The metal IR filter layer is arranged on a surface of the optomechanical structure. The sensing pixel senses an optical image of an object located above the optomechanical structure through the optomechanical structure and the metal IR filter layer. The metal IR filter layer blocks infrared light from the environment where the object is located from entering the sensing pixel, and the metal The thickness of the IR filter layer is between 1 and 0.1 μm.

The present invention also provides an electronic device, which at least includes: a housing; a display arranged on the housing; and the optical biometric sensor arranged between the display and the housing, wherein the object is located on or above the display , The display shows information in the direction of the object.

Using the above-mentioned optical biometric sensor and electronic equipment using it, It can reduce the thickness of the metal IR filter layer, solve the stress problem caused by the traditional IR filter layer on the optical sensor chip and the problem of uneven edge image, and realize the function of thinner under-screen optical sensing:

In order to make the above-mentioned content of the present invention more obvious and understandable, the following is a detailed description of preferred embodiments in conjunction with the accompanying drawings.

A1: The first area

A2: second area

A3: The third area

A4: The fourth area

F: Object

S1: Fingerprint sensing area

S2: Distribution area

S3: area

T: thickness

10: Optical sensor chip

10T: upper surface

11: substrate

12: Sensing pixels

13: Electrical connection pad

20: Optical machine structure

20B: Surface

20T: upper surface

30: Metal IR filter layer

100: Optical biometric sensor

200: electronic equipment

210: Shell

220: display

221: Transparent substrate

222: Transparent substrate

300: Optical fingerprint sensor module

310: Fingerprint sensor chip

320: Optical machine structure

330: IR filter layer

332: Glass substrate

334: IR filter film

[Figure 1] shows a schematic diagram of a traditional optical fingerprint sensor module.

[Figure 2] shows a schematic diagram of another conventional optical fingerprint sensor module.

[Figure 3] shows a schematic partial top view of a conventional optical fingerprint sensor module.

[Figure 4] A partial top view showing a variation of the optical fingerprint sensor module of [Figure 3]

[Figure 5] shows a schematic diagram of the optical biometric sensor of the preferred embodiment of the present invention.

[FIG. 6] A schematic diagram showing a modification of the optical biometric sensor of the preferred embodiment of the present invention.

[Figure 7] shows a schematic diagram of the electronic device of the preferred embodiment of the present invention.

[FIG. 8] A schematic diagram showing another example of the electronic device of the preferred embodiment of the present invention.

The embodiment of the present invention provides an optical biometric sensor, which is directly on the optical sensor chip and firstly uses physical vapor deposition (PVD) (including but not limited to sputtering or evaporation). )) A metal IR filter layer is formed through the process, and then an optomechanical structure is fabricated. The thickness of the metal IR filter layer can be less than <1μm, which is only about one-tenth of the thickness of the IR filter layer made of SiO ₂ /TiO _2. In addition to the thinner thickness, it can also solve the problem of the filter layer. Problems such as chip stress and uneven edge image.

As shown in FIG. 5, the optical biometric sensor 100 at least includes an optical sensor chip 10, an optomechanical structure 20 and a metal IR filter layer 30. In this embodiment, an optical fingerprint sensor is taken as an example for description, but the present invention is not limited to this. The optical biometric sensor 100 can also sense the blood vessel image and blood oxygen concentration of the finger. Biological features such as images, or biological features such as face shape and iris.

The optical sensor chip 10 includes at least a substrate 11 and a plurality of sensor pixels 12, which are formed on the substrate 11 and arranged in a two-dimensional array. It is worth noting that although a plurality of sensing pixels 12 are taken as an example for illustration, the present disclosure is also applicable to the example of a single sensing pixel without the existence of a two-dimensional array.

In this embodiment, the substrate 11 is a semiconductor substrate, and the optical sensor chip 10 is a CIS sensor chip manufactured by a semiconductor process. Because it is compatible with a semiconductor process, it can be mass-produced and reduced costs.

The optomechanical structure 20 is located above the sensing pixels 12. In an example, the opto-mechanical structure 20 may include a light hole, a light shielding layer, a micro lens, etc., or may be formed by a semiconductor process. In another example, the optical-mechanical structure 20 includes a collimator.

The metal IR filter layer 30 is disposed on a surface 20B of the optomechanical structure 20. In other words, the metal IR filter layer 30 is formed on an upper surface 10T of the optical sensor chip 10 by a PVD sputtering process, so that the metal IR filter layer 30 and the optical sensor chip 10 can form a bond. The bonding includes, but is not limited to, for example, the bonding between metal atoms and the surface of oxides (such as silicon oxide or silicon dioxide), and is different from traditional adhesive bonding. This is also compatible with the semiconductor manufacturing process, so the entire optical biometric sensor 100 can be manufactured using commercial semiconductor manufacturing equipment and manufacturing processes, which has the advantages of mass production and cost reduction. In one example, after the sensing pixels 12 are formed on the substrate 11, interconnects and metal interlayers are formed on the sensing pixels 12 After the dielectric layer, the interlayer dielectric layer, and the protective layer (such as silicon oxide or silicon dioxide), etc., PVD, vapor deposition or sputtering processes are performed to form the metal IR filter layer 30.

In actual operation, these sensing pixels 12 sense an optical image of an object F located above the optomechanical structure 20 through the optical mechanical structure 20 and the metal IR filter layer 30, and the metal IR filter layer 30 blocks the object F. Infrared light from the environment enters these sensing pixels 12 to avoid interference of biological feature sensing under sunlight or infrared light source. Here, the thickness T of the metal IR filter layer 30 is between 1 μm and 0.1 μm.

With the optical biometric sensor 100 described above, since the thickness of the metal IR filter layer 30 is greatly reduced, the stress problem caused by the metal IR filter layer 30 on the optical sensor chip is eliminated. In addition, spin-coating photoresist or depositing a dielectric layer with etching on the metal IR filter layer 30 will not cause an uneven structure on the edge of the metal IR filter layer 30, so it can solve the uneven edge image. The problem. Furthermore, the thickness of the optical biometric sensor can be reduced.

In addition, in this embodiment, a first area A1 of the two-dimensional array is equal to a second area A2 of the metal IR filter layer 30, and the first area A1 is equal to a third area A3 of the optical mechanical structure 20 and smaller than the substrate A fourth area of 11 A4. In this situation, because the metal IR filter layer 30 is spin-coated with a photoresist or a dielectric layer is deposited with etching, etc., it will not cause uneven structure on the edge of the metal IR filter layer 30. The jitter of the sensing signal does not need to increase the second area A2 of the metal IR filter layer 30. The area mentioned in this disclosure refers to the area corresponding to the horizontal plane of the drawing. It is worth noting that the first area A1 represents the area where the sensing pixels 12 are distributed, and the pitch of the sensing pixels 12 can also be calculated. For example, the first area A1 can extend to the outermost sensing pixels 12 and add The previous one or half pitch. With this configuration, the metal IR filter layer 30 can still filter the oblique infrared light that is about to enter the surrounding sensing pixels 12.

In other examples, the thickness of the metal IR filter layer 30 is between 0.9 and 0.2 μm; between 0.8 and 0.3 μm; between 0.7 and 0.4 μm; between 0.7 and 0.5 μm; Between 0.65 and 0.55μm; or between 0.6 and 0.5μm. In an example, the thickness of the metal IR filter layer 30 is equal to 0.6 μm. The metal IR filter layer 30 is disposed between the optical sensor chip 10 and the optomechanical structure 20, especially between the sensing pixels 12 and the optomechanical structure 20. In addition, the optical sensor chip 10 further includes a plurality of electrical connection pads 13 located outside the two-dimensional array, and the metal IR filter layer 30 does not cover the electrical connection pads 13. The metal IR filter layer 30 is mainly a metal thin film layer, such as an Ag thin film layer, and the thickness of the IR filter layer can be greatly reduced by using the characteristic of Ag to absorb light. The metal IR filter layer 30 may have a single-layer structure or a multi-layer structure. In addition to Ag, its material includes a single layer or a combination of multiple layers such as Ti, Ta, Al, and Cu.

Therefore, manufacturing the optical biometric sensor 100 of FIG. 5 includes the following steps. First, the sensing pixel 12 and the interconnections above it, the metal interlayer dielectric layer, the interlayer dielectric layer, and the protective layer are formed on the substrate 11. Then, a PVD process is performed on the optical sensor chip 10 to form the metal IR filter layer 30, and then the optical mechanical structure 20 is formed on the metal IR filter layer 30. It is worth noting that the substrate 11 may be a semiconductor substrate or a glass substrate or other insulating substrate. In this case, the optical biometric sensor 100 may be a light produced by an independent thin-film transistor (TFT) process. Sensor; or a photo sensor made by a complementary metal-oxide semiconductor (CMOS) process. In addition, the optical biometric sensor 100 is, for example, an in-cell optical sensor integrated with a TFT liquid crystal display (LCD) or a TFT organic light emitting diode (Organic Light Emitting Diode, OLED). .

Sputtering is a type of PVD, which refers to the physical process in which atoms in a solid target are impacted by high-energy ions (usually from plasma) and leave the solid to enter the gas. Sputtering can be In a vacuum system filled with inert gas, the argon gas is ionized by the action of a high-voltage electric field to generate an argon ion current, which bombards the target cathode, and the sputtered target material atoms or molecules precipitate and accumulate on semiconductor wafers, glass, or ceramics. To form a thin film. The advantage of sputtering is that thin films of high melting point materials can be prepared at a lower temperature. The thin films can be bonded to the substrate and are not easy to peel off, and will not cause stress to the substrate. The original composition is maintained during the preparation of alloy and compound thin films. Change, so it has been widely used in the manufacture of semiconductor devices and integrated circuits.

In another example, a PVD vapor deposition process, such as an E-gun electron gun vapor deposition process, can also be used to form the metal IR filter layer 30. The vapor deposition principle is to place the desired vapor deposition in a high vacuum chamber. A coating technology that uses electric heating wires or electron beams to heat up to melting and vaporization temperature, so that the material evaporates, reaches and adheres to the surface of the substrate. During the evaporation process, the surface temperature of the object to be plated has an important influence on the characteristics of the thin film formed by evaporation. The substrate needs to be heated appropriately so that the vapor-deposited atoms can move freely on the surface of the substrate, so that a uniform film can be formed. When the substrate is heated to above 150°C, a good bond can be formed between the deposited film and the substrate without peeling off.

As shown in FIG. 6, this example is similar to FIG. 5. The difference is that the optomechanical structure 20 is disposed on the optical sensor chip 10 and the metal IR filter layer 30 is far away from the sensor pixels 12. That is, the metal IR filter layer 30 is disposed on an upper surface 20T of the optomechanical structure 20. In this case, the metal IR filter layer 30 and the optomechanical structure 20 can form a bond. In addition, the optical sensor chip 10 further includes a plurality of electrical connection pads 13 located outside the two-dimensional array, and the optical-mechanical structure 20 does not cover these electrical connection pads 13.

Therefore, manufacturing the optical biometric sensor 100 of FIG. 6 includes the following steps. First, the sensing pixel 12 and the interconnections above it, the metal interlayer dielectric layer, the interlayer dielectric layer, and the protective layer are formed on the substrate 11. Then, an optomechanical structure 20 is formed on the optical sensor chip 10. Next, a PVD process is performed on the optomechanical structure 20 to form a metal IR filter Light layer 30.

As shown in FIG. 7, the present invention also provides an electronic device 200, such as a mobile device such as a mobile phone, which at least includes a housing 210, a display 220, and an optical biometric sensor 100. The display 220 and the optical biometric sensor 100 may be powered by the battery 230 of the electronic device 200. The display 220 is disposed on the housing 210. The optical biometric sensor 100 is disposed between the display 220 and the housing 210. The object F is located on or above the display 220, and the display 220 displays information in the direction of the object F to interact with the user. The display 220 is, for example, an OLED display, a micro-light-emitting diode display, etc., and may have a touch function at the same time.

As shown in Figure 8, this example is similar to Figure 7, the difference is that the substrate 11 of the optical biometric sensor 100 is a glass substrate, and the glass substrate is one of the two opposing transparent substrates 221, 222 of the display 220 ( 8 refers to the light-transmitting substrate 221 below. It can also be said that the glass substrate is a part of the light-transmitting substrate 221, so that the optical biometric sensor 100 is embedded in the display 220. Therefore, the optical biometric sensor of FIG. The sensor 100 is a TFT sensor, which is an LCD or OLED embedded sensor.

Using the above-mentioned optical biometric sensor and the electronic equipment using it, the thickness of the metal IR filter layer can be reduced, and the problem of stress caused by the traditional IR filter layer on the optical sensor chip and the problem of uneven edge images can be solved. Realize the function of thinner under-screen optical sensing.

The specific embodiments proposed in the detailed description of the preferred embodiments are only used to facilitate the description of the technical content of the present invention, rather than restricting the present invention to the above embodiments in a narrow sense, and do not exceed the spirit of the present invention and the scope of the patent application. Under the circumstance, the various changes and implementations made belong to the scope of this new model.

A1: The first area

A2: second area

A3: The third area

A4: The fourth area

F: Object

T: thickness

10: Optical sensor chip

10T: upper surface

11: substrate

12: Sensing pixels

13: Electrical connection pad

20: Optical machine structure

20B: Surface

20T: upper surface

30: Metal IR filter layer

100: Optical biometric sensor

Claims (13)

An optical biometric sensor, including at least: An optical sensor chip, including at least: A substrate; and One or more sensing pixels formed on the substrate; An opto-mechanical structure located above the one or more sensing pixels; and A metal IR filter layer is arranged on a surface of the optomechanical structure, wherein the one or more sensing pixels sense an object located above the optomechanical structure through the optomechanical structure and the metal IR filter layer In an optical image of, the metal IR filter layer blocks infrared light from the environment where the object is located from entering the one or more sensing pixels, and the thickness of the metal IR filter layer is between 1 μm and 0.1 μm . The optical biometric sensor according to claim 1, wherein the plurality of sensing pixels are arranged in a two-dimensional array, and a first area of the two-dimensional array is equal to a second area of the metal IR filter layer . The optical biometric sensor according to claim 2, wherein the first area is equal to a third area of the optical mechanical structure and smaller than a fourth area of the substrate. The optical biometric sensor according to claim 1, wherein the thickness of the metal IR filter layer is between 0.7 and 0.5 μm. The optical biometric sensor according to claim 1, wherein the thickness of the metal IR filter layer is between 0.65 and 0.55 μm. The optical biometric sensor according to claim 1, wherein the metal IR filter layer is disposed between the one or more sensing pixels and the optomechanical structure. The optical biometric sensor according to claim 6, wherein the plurality of sensing pixels are arranged in a two-dimensional array, and the optical sensor chip further includes a plurality of electrical connection pads located outside the two-dimensional array, The metal IR filter layer does not cover the electrical connection pads. The optical biometric sensor according to claim 6, wherein the metal IR filter layer and the optical sensor chip form a bond. The optical biometric sensor according to claim 1, wherein the opto-mechanical structure is disposed on the optical sensing chip, and the metal IR filter layer is far away from the one or more sensing pixels. The optical biometric sensor according to claim 9, wherein the plurality of sensing pixels are arranged in a two-dimensional array, and the optical sensor chip further includes a plurality of electrical connection pads located outside the two-dimensional array, The optomechanical structure does not cover the electrical connection pads. The optical biometric sensor according to claim 9, wherein the metal IR filter layer forms a bond with the optomechanical structure. An electronic device including at least: A shell A display installed on the housing; and The optical biometric sensor according to any one of claims 1 to 11, which is arranged between the display and the housing, wherein the object is located on or above the display, and the display is displayed in the direction of the object Information. The electronic device according to claim 12, wherein the substrate of the optical biometric sensor is a glass substrate, and the glass substrate is one of two opposing transparent substrates of the display, so that the optical biometric sensor is The detector is embedded in the display.

Images