Optical fingerprint device and manufacturing method thereof

Abstract

The present invention provides an optical fingerprint device and a manufacturing method thereof, comprising providing an image sensor wafer, on which an internal pad is formed; arranging a light-transmitting layer on the image sensor wafer; arranging an external pad on the light-transmitting layer, wherein the external pad is electrically connected to the internal pad; thereby solving the problem of low efficiency in opening the pad by etching process in the prior art, improving production efficiency, increasing production capacity, and reducing manufacturing costs.

Description

Technical Field

[0001] The invention relates to an optical fingerprint device and a manufacturing method thereof. Background Art

[0002] The current fingerprint recognition solutions include optical technology, silicon technology (capacitive / radio frequency), ultrasonic technology, etc. Among them, optical fingerprint recognition technology has been widely used in portable electronic devices.

[0003] Optical fingerprint recognition technology uses optical imaging equipment based on the principle of total reflection of light (FTIR). Light shines on the surface of the light-transmitting layer (such as organic or inorganic glass) with fingerprints pressed on it, and the reflected light is captured by the image sensor. The amount of reflected light depends on the depth of the fingerprint ridges and valleys pressed on the glass surface, as well as the oil and moisture between the skin and the glass. After the light passes through the glass and reaches the center of the valley, it is totally reflected at the interface between the glass and the air, and the light is reflected to the image sensor, while the light directed to the ridge is not totally reflected, but is absorbed by the contact surface between the ridge and the glass or diffusely reflected to other centers, thus forming an image of the fingerprint on the image sensor.

[0004] Since a larger microlens is required to increase the energy of the incident light and achieve higher image quality, in the prior art, it is often necessary to set a thicker light-transmitting layer (more than 50 μm) above the pixel unit and a thicker light-blocking structure (for example, 15-50 μm) between the pixel units to solve the problem of incident light entering the adjacent pixel units of the image sensor, thereby causing signal crosstalk, and improve the optical performance of the optical fingerprint device. However, it should be noted that the light-transmitting layer and the light-blocking structure need to avoid the pad area of ​​the image sensor to avoid affecting the electrical connection performance of the pad area.

[0005] The manufacturing method of the optical fingerprint device in the prior art is as follows Figure 1 , Figure 2 As shown, a pixel unit 101 and a pad 102 are formed on an image sensor wafer 100. After a light blocking structure 103 is formed on the surface of the image sensor wafer 100, a light-transmitting layer 104 is set on the light blocking structure 103, and then the light blocking structure 103 and the light-transmitting layer 104 corresponding to the pad 102 are removed by a dry etching process, thereby exposing the pad 102 so as to be electrically connected to an external power source through the pad 102. However, generally, dry etching can only remove 5-10 μm of thickness at a time, and it generally takes 0.5-1 minute to remove 1 μm, so the removal efficiency is relatively low, the production capacity is very limited, and the manufacturing cost is increased. Summary of the invention

[0006] The object of the present invention is to provide an optical fingerprint device and a manufacturing method thereof, so as to improve production efficiency, increase production capacity and reduce manufacturing costs.

[0007] Based on the above considerations, one aspect of the present invention provides a method for manufacturing an optical fingerprint device, comprising the following steps: S100: providing an image sensor wafer, on which an internal pad is formed; S200: arranging a light-transmitting layer on the image sensor wafer; S300: arranging an external pad on the light-transmitting layer, wherein the external pad is electrically connected to the internal pad; thereby forming the optical fingerprint device.

[0008] Preferably, a metal layer for connecting the external pad and the internal pad is formed in the light-transmitting layer.

[0009] Preferably, a contact hole is formed in the light-transmitting layer by laser drilling, and the metal layer is filled in the contact hole.

[0010] Preferably, laser drilling is used to directly form a contact hole whose depth reaches the surface of the internal pad.

[0011] Preferably, a contact hole whose depth does not reach the surface of the internal pad is first formed by laser drilling, and then the depth of the contact hole is expanded by etching until it reaches the surface of the internal pad.

[0012] Preferably, a groove is formed in the light-transmitting layer by mechanical cutting, and the surface of the groove is covered with the metal layer.

[0013] Preferably, the metal layer and the image sensor wafer are isolated by an insulating layer.

[0014] Preferably, a light blocking structure is provided between the image sensor wafer and the light-transmitting layer, and the metal layer passes through the light blocking structure.

[0015] Preferably, an infrared cut-off filter film is provided between the image sensor wafer and the light-transmitting layer, and the metal layer passes through the infrared cut-off filter film.

[0016] Preferably, a microlens is also provided on the light-transmitting layer.

[0017] Another aspect of the present invention provides an optical fingerprint device, comprising: an image sensor wafer having an internal pad formed thereon; a light-transmitting layer disposed on the image sensor wafer; and an external pad disposed on the light-transmitting layer, the external pad being electrically connected to the internal pad.

[0018] Preferably, the optical fingerprint device further comprises a metal layer formed in the light-transmitting layer for connecting the external pad and the internal pad.

[0019] Preferably, the optical fingerprint device further comprises a contact hole formed in the light-transmitting layer and filled with the metal layer.

[0020] Preferably, the optical fingerprint device further comprises a groove formed in the light-transmitting layer and covered with the metal layer.

[0021] Preferably, the optical fingerprint device further includes an insulating layer for isolating the metal layer from the image sensor wafer.

[0022] Preferably, the optical fingerprint device further comprises a light-blocking structure arranged between the image sensor wafer and the light-transmitting layer, and the metal layer passes through the light-blocking structure.

[0023] Preferably, the optical fingerprint device further comprises an infrared cut-off filter film disposed between the image sensor wafer and the light-transmitting layer, and the metal layer passes through the infrared cut-off filter film.

[0024] Preferably, the optical fingerprint device further comprises a microlens arranged on the light-transmitting layer.

[0025] The optical fingerprint device and the manufacturing method thereof of the present invention include providing an image sensor wafer, on which an internal pad is formed; arranging a light-transmitting layer on the image sensor wafer; arranging an external pad on the light-transmitting layer, and the external pad is electrically connected to the internal pad; thereby solving the problem of low efficiency of opening the pad by etching process in the prior art, improving production efficiency, increasing production capacity, and reducing manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Other features, objects and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings.

[0027] Figure 1-Figure 2 A schematic diagram of a process for manufacturing an optical fingerprint device in the prior art;

[0028] Figure 3-Figure 5 A schematic diagram of a process of manufacturing an optical fingerprint device according to a preferred embodiment of the present invention;

[0029] Figure 6-Figure 10 Schematic diagram of a method for manufacturing an optical fingerprint device according to another preferred embodiment of the present invention.

[0030] In the drawings, the same or similar reference numerals denote the same or similar devices (modules) or steps throughout different drawings. DETAILED DESCRIPTION

[0031] In order to solve the problems in the above-mentioned prior art, the present invention provides an optical fingerprint device and a manufacturing method thereof, including providing an image sensor wafer, on which an internal pad is formed; arranging a light-transmitting layer on the image sensor wafer; arranging an external pad on the light-transmitting layer, and the external pad is electrically connected to the internal pad; thereby solving the problem of low efficiency of opening the pad through an etching process in the prior art, improving production efficiency, increasing production capacity, and reducing manufacturing costs.

[0032] In the following specific description of the preferred embodiments, reference will be made to the attached drawings which constitute a part of the present invention. The attached drawings show by way of example specific embodiments that can implement the present invention. The illustrative embodiments are not intended to be exhaustive of all embodiments according to the present invention. It will be appreciated that other embodiments may be utilized, and structural or logical modifications may also be made without departing from the scope of the present invention. Therefore, the following specific description is not restrictive, and the scope of the present invention is limited by the appended claims.

[0033] The present invention is described in detail below with reference to specific embodiments.

[0034] One aspect of the present invention provides a method for manufacturing an optical fingerprint device, comprising the following steps: S100: providing an image sensor wafer, on which an internal pad is formed; S200: arranging a light-transmitting layer on the image sensor wafer; S300: arranging an external pad on the light-transmitting layer, wherein the external pad is electrically connected to the internal pad; thereby forming the optical fingerprint device.

[0035] Embodiment 1

[0036] Figure 3-Figure 5 The figure is a schematic diagram of a method for manufacturing an optical fingerprint device according to a preferred embodiment of the present invention.

[0037] See also Figure 3 , an image sensor wafer 200 is provided, on which a pixel unit 201 and an internal pad 202 are formed; a light-transmitting layer 204 is provided on the image sensor wafer 200. An infrared cut-off filter film 210 and a light-blocking structure 203 are provided between the image sensor wafer 200 and the light-transmitting layer 204. Preferably, a microlens 205 is provided on the light-transmitting layer 204, and further preferably, a light-blocking layer (not shown) formed of, for example, a black glue material may be further formed between the microlenses 205, so as to further reduce signal interference caused by light crosstalk.

[0038] See also Figure 4, a contact hole 208 is formed in the light-transmitting layer 204 by laser drilling. When the infrared cut-off filter film 210 and the light-blocking structure 203 are present between the image sensor wafer 200 and the light-transmitting layer 204, the contact hole 208 passes through the infrared cut-off filter film 210 and the light-blocking structure 203. Specifically, the contact hole 208 whose depth reaches the surface of the internal pad 202 can be directly formed by laser drilling, or the contact hole 208 whose depth does not reach the surface of the internal pad 202 can be first formed by laser drilling, and then the depth of the contact hole 208 is expanded by etching until it reaches the surface of the internal pad 202.

[0039] See also Figure 5 A metal layer 207 (e.g., copper-nickel-gold) is filled in the contact hole 208 by sputtering, electroplating, or chemical plating, and an external pad 206 is arranged on the light-transmitting layer 204. The metal layer 207 passes through the infrared cutoff filter 210, the light-blocking structure 203, and the light-transmitting layer 204, so as to electrically connect the external pad 206 with the internal pad 202, so as to electrically connect to an external power source through the external pad 206, thereby solving the problem of low efficiency of opening the pad by etching process in the prior art, improving production efficiency, increasing production capacity, and reducing manufacturing costs.

[0040] Another aspect of the present invention provides an optical fingerprint device, see Figure 5 The optical fingerprint device includes: an image sensor wafer 200, on which an internal pad 202 is formed; a light-transmitting layer 204 disposed on the image sensor wafer 200; and an external pad 206 disposed on the light-transmitting layer 204. A contact hole 208 formed in the light-transmitting layer 204 is filled with a metal layer 207, and the metal layer 207 electrically connects the external pad 206 with the internal pad 202, so as to be electrically connected to an external power source through the external pad 206.

[0041] Preferably, the optical fingerprint device further includes an infrared cutoff filter film 210 and a light blocking structure 203 disposed between the image sensor wafer 200 and the light-transmitting layer 204 , and the metal layer 207 passes through the infrared cutoff filter film 210 and the light blocking structure 203 .

[0042] Preferably, the optical fingerprint device further comprises microlenses 205 arranged on the light-transmitting layer 204 and light-blocking layers (not shown) arranged between the microlenses 205 .

[0043] Embodiment 2

[0044] Figure 6-Figure 10 Schematic diagram of a method for manufacturing an optical fingerprint device according to another preferred embodiment of the present invention.

[0045] See also Figure 6, an image sensor wafer 300 is provided, on which a pixel unit 301 and an internal pad 302 are formed; a light-transmitting layer 304 is provided on the image sensor wafer 300. An infrared cut-off filter film 310 and a light-blocking structure 303 are provided between the image sensor wafer 300 and the light-transmitting layer 304. Preferably, a microlens 305 is provided on the light-transmitting layer 304, and further preferably, a light-blocking layer (not shown) formed of, for example, a black glue material may be further formed between the microlenses 305, so as to further reduce signal interference caused by light crosstalk.

[0046] See also Figure 7 A groove 308 is formed in the light-transmitting layer 304 in the vicinity of the cutting path (not shown) by mechanical cutting. When an infrared cut-off filter film 310 and a light-blocking structure 303 are present between the image sensor wafer 300 and the light-transmitting layer 304, the groove 308 passes through the infrared cut-off filter film 310 and the light-blocking structure 303. Due to the process limitation of mechanical cutting, the groove 308 usually penetrates into and damages the surface of the image sensor wafer 300.

[0047] See also Figure 8 The surface of the groove 308 is covered with an insulating layer 309 .

[0048] See also Fig. 9 The insulating layer 309 on the sidewall of the groove 308 is cut away by mechanical cutting, and the insulating layer 309 at the bottom of the groove 308 is retained.

[0049] See also Fig.10 A metal layer 307 is covered on the surface of the groove 308 by sputtering, electroplating or chemical plating, and an insulating layer 309 retained at the bottom of the groove 308 is used to isolate the metal layer 307 from the image sensor wafer 300. An external pad 306 is set on the light-transmitting layer 304. The metal layer 307 passes through the infrared cutoff filter 310, the light-blocking structure 303 and the light-transmitting layer 304, and the external pad 306 is electrically connected to the internal pad 302, so as to be electrically connected to an external power supply through the external pad 306, thereby solving the problem of low efficiency of opening the pad through the etching process in the prior art, improving production efficiency, increasing production capacity, and reducing manufacturing costs.

[0050] In addition, in other embodiments not shown, an insulating layer may be further covered on the metal layer 307 to protect and isolate the metal layer 307 .

[0051] Another aspect of the present invention provides an optical fingerprint device, see Fig.10The optical fingerprint device includes: an image sensor wafer 300, on which an internal pad 302 is formed; a light-transmitting layer 304 disposed on the image sensor wafer 300; and an external pad 306 disposed on the light-transmitting layer 304. The surface of the groove 308 formed in the light-transmitting layer 304 is covered with a metal layer 307, and the metal layer 307 is isolated from the image sensor wafer 300 by an insulating layer 309. The metal layer 307 electrically connects the external pad 306 with the internal pad 302, so as to be electrically connected to an external power source through the external pad 306.

[0052] Preferably, the optical fingerprint device further includes an infrared cutoff filter film 310 and a light blocking structure 303 disposed between the image sensor wafer 300 and the light-transmitting layer 304 , and the metal layer 307 passes through the infrared cutoff filter film 310 and the light blocking structure 303 .

[0053] Preferably, the optical fingerprint device further comprises microlenses 305 arranged on the light-transmitting layer 304 and light-blocking layers (not shown) arranged between the microlenses 305 .

[0054] In summary, the optical fingerprint device and the manufacturing method thereof of the present invention include providing an image sensor wafer, on which an internal pad is formed; arranging a light-transmitting layer on the image sensor wafer; arranging an external pad on the light-transmitting layer, and the external pad is electrically connected to the internal pad; thereby solving the problem of low efficiency of opening the pad through an etching process in the prior art, improving production efficiency, increasing production capacity, and reducing manufacturing costs.

[0055] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, in any case, the embodiments should be considered exemplary and non-restrictive. Furthermore, it is apparent that the term "comprising" does not exclude other elements and steps, and the wording "a" does not exclude the plural. Multiple elements stated in a device claim may also be implemented by one element. The words first, second, etc. are used to indicate names and do not indicate any particular order.

Claims

1. A method for manufacturing an optical fingerprint device, characterized in that: The steps include: S100: Providing an image sensor wafer, on which pixel units and internal pads are formed; S200: Disposing a light-transmitting layer on the image sensor wafer and disposing a light-blocking structure between the image sensor wafer and the light-transmitting layer, wherein the light-blocking structure and the light-transmitting layer cover the internal pad; S300: Disposing an external pad and a microlens corresponding to the pixel unit on the light-transmitting layer, and electrically connecting the external pad with the internal pad through a metal layer passing through the light-blocking structure and the light-transmitting layer; Thus, the optical fingerprint device is formed.

2. The method for manufacturing an optical fingerprint device according to claim 1, characterized in that: A contact hole is formed in the light-transmitting layer by laser drilling, and the metal layer is filled in the contact hole.

3. The method for manufacturing an optical fingerprint device according to claim 2, characterized in that: Laser drilling is used to directly form contact holes that reach the surface of the internal pad.

4. The method for manufacturing an optical fingerprint device according to claim 2, characterized in that: Firstly, a contact hole whose depth does not reach the surface of the internal pad is formed by laser drilling, and then an etching method is used to expand the depth of the contact hole until it reaches the surface of the internal pad.

5. The method for manufacturing an optical fingerprint device according to claim 1, characterized in that: A groove is formed in the light-transmitting layer by mechanical cutting, and the surface of the groove is covered with the metal layer.

6. The method for manufacturing an optical fingerprint device according to claim 5, characterized in that: The metal layer is isolated from the image sensor wafer by an insulating layer.

7. The method for manufacturing an optical fingerprint device according to claim 1, characterized in that: An infrared cut-off filter film is arranged between the image sensor wafer and the light-transmitting layer, and the metal layer passes through the infrared cut-off filter film.

8. An optical fingerprint device, characterized in that: include: An image sensor wafer having pixel units and internal pads formed thereon; a light-transmitting layer disposed on the image sensor wafer and a light-blocking structure disposed between the image sensor wafer and the light-transmitting layer, wherein the light-blocking structure and the light-transmitting layer cover the internal pads; An external pad is arranged on the light-transmitting layer and a microlens corresponding to the pixel unit, and the external pad is electrically connected to the internal pad via a metal layer passing through the light-blocking structure and the light-transmitting layer.

9. The optical fingerprint device according to claim 8, characterized in that: Also included is a contact hole formed in the light-transmitting layer and filled with the metal layer.

10. The optical fingerprint device according to claim 8, characterized in that: Also included is a groove formed in the light-transmitting layer and covered with the metal layer.

11. The optical fingerprint device according to claim 10, characterized in that: An insulating layer is also included for isolating the metal layer from the image sensor wafer.

12. The optical fingerprint device according to claim 8, characterized in that: It also includes an infrared cut-off filter film arranged between the image sensor wafer and the light-transmitting layer, and the metal layer passes through the infrared cut-off filter film.

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