CN106972007A - Fingerprint sensing and identifying device with antistatic structure - Google Patents

Abstract

The invention discloses a fingerprint sensing and identifying device with an antistatic structure, which adopts an integrally formed substrate, wherein the surface of the substrate is provided with at least one groove for mounting a sensing chip, and an electrostatic discharge protection circuit is formed on the surface of the substrate around the groove and is connected with a conductive post penetrating through the substrate, so that the electrostatic discharge protection circuit is electrically connected with a conductive pad at the bottom of the substrate, and the fingerprint sensing and identifying device has an antistatic protection effect, thereby improving the accuracy of fingerprint sensing and identifying; meanwhile, the electrostatic discharge protection circuit and the substrate can be combined together through integral forming, so that the purposes of thinning a packaging structure and simplifying a packaging process can be achieved.

Description

Fingerprint sensing and identification device with antistatic structure

technical field

The invention relates to a fingerprint recognition device, in particular to a fingerprint sensing and recognition device with an antistatic structure which can reduce the package size and simplify the manufacturing process.

Background technique

Fingerprint sensing and identification is a kind of biometric identification technology, which uses unique fingerprint information on human fingers for identification, and is widely used for its advantages in safety and convenience. However, since the user's fingertip must be in contact with the sensing surface during fingerprint identification, the electrostatic charge generated on the surface of the fingertip may pass through the sensing surface, causing the sensing chip to be subjected to electrostatic discharge (ESD) damage.

In the antistatic design of existing fingerprint sensing and identification devices, the antistatic structure is mainly fabricated directly on the sensing chip, and then packaged to realize the antistatic function. As shown in FIG. 1 , an existing fingerprint sensing and identification device 10 with an antistatic structure is installed on the upper surface of a substrate 10 with a fingerprint reader chip 12 and electrically connected to the substrate through a plurality of bonding wires 14. 10 and the fingerprint identification chip 12, the electrostatic discharge strip 16 protrudes from the active surface 121 of the fingerprint reader chip 12, the encapsulant 18 is formed on the substrate 10 and surrounds the fingerprint reader chip 12, and the encapsulant 18 partially covers the fingerprint identification A predetermined position on the active surface 121 of the fingerprint reader chip 12 is connected to the electrostatic discharge strip 16, so that the electrostatic discharge strip 16 is partially exposed on the edge of the opening of the sealant 18, so as to achieve the purpose of electrostatic discharge on the active surface 121 of the fingerprint reader chip 12 .

However, since the above-mentioned prior patent is to protrude the electrostatic discharge strip 16 on the active surface 121 of the fingerprint reader chip 12, the packaging process is relatively complicated, and the function of the chip itself is likely to be damaged during the packaging process. In addition, due to the packaging structure Upward stacking will increase the package volume and package thickness, making it difficult to meet the requirements of thin and light packages.

Contents of the invention

The main purpose of the present invention is to provide a fingerprint sensing and identification device with an antistatic structure, which uses a substrate integrally formed with at least one groove to accommodate the sensing chip, and forms static electricity on the surface of the substrate around the groove. The discharge protection circuit, and the electrostatic discharge protection circuit is electrically connected to the conductive pad at the bottom of the substrate through the conductive column to achieve anti-static protection, thereby improving the accuracy of fingerprint sensing and identification.

Another object of the present invention is to provide a fingerprint sensing and identification device with an antistatic structure, which integrates the electrostatic discharge protection circuit and the substrate through integral molding, the manufacturing process is simple, and the volume of the components is simplified at the same time.

In order to achieve the above object, the present invention discloses a fingerprint sensing and identification device with an antistatic structure, which mainly includes a substrate, a sensing chip and at least one electrostatic discharge protection circuit, wherein the substrate has a first surface, a second surface and At least one conductive post passing through the first surface and the second surface, the first surface is integrally formed with a first groove, the second surface is provided with at least one conductive pad, and the conductive post is located around the first groove and connected to the conductive pad connected; the sensing chip is arranged in the first groove; the electrostatic discharge protection circuit is arranged on the first surface and is located around the first groove, and the electrostatic discharge protection circuit is connected with the conductive column to electrically connect and conduct through the conductive column pad.

Specifically, the substrate may be an insulating substrate; preferably, the insulating substrate may be a ceramic substrate.

Specifically, the fingerprint sensing and identification device with an antistatic structure further includes an encapsulation adhesive layer, and the encapsulation adhesive layer at least fills the first groove. Also, the encapsulation glue layer can be epoxy resin or silicone. Further, the fingerprint sensing and identification device with an antistatic structure further includes a touch panel, the touch panel at least covers the sensing chip and exposes the electrostatic discharge protection circuit.

Specifically, at least one second groove is integrally formed on the first surface of the substrate.

Specifically, the electrostatic discharge protection circuit may be a continuous or discontinuous ring.

Specifically, the cross section of the conductive pillar is square or trapezoidal.

The fingerprint sensing and identification device with antistatic structure provided by the present invention can not only effectively resist static electricity, but also reduce the packaging size and simplify the packaging process. It is not only different from the existing structure, but also can effectively overcome various problems existing therein.

Description of drawings

1 is a cross-sectional view of an existing fingerprint sensing and identification device with electrostatic discharge strips;

2 is a perspective view of a fingerprint sensing and identification device with an antistatic structure according to a first embodiment of the present invention;

3 is a cross-sectional view of a fingerprint sensing and identification device with an antistatic structure according to a first embodiment of the present invention;

4 is a perspective view of a fingerprint sensing and identification device with an antistatic structure according to a second embodiment of the present invention;

5 is a cross-sectional view of a fingerprint sensing and identification device with an antistatic structure according to a second embodiment of the present invention;

6A and 6B are cross-sectional views of different implementations of conductive pillars in the fingerprint sensing and identification device with antistatic structure according to the second embodiment of the present invention.

Explanation of reference signs: 10-substrate; 12-fingerprint identification chip; 121-active surface; 14-welding wire; 16-electrostatic discharge strip; -substrate; 24-groove; 26-conductive column; 28-conducting pad; 30-electrostatic discharge protection circuit; 32-sensing chip; 34-packaging adhesive layer; 36-touch panel; Fingerprint sensing identification device; 42-substrate; 44-first groove; 46-conductive column; 48-conducting pad; 50-electrostatic discharge protection circuit; 52-sensing chip; plate; 58-second groove; 60-light emitting element.

detailed description

FIG. 2 is a perspective view of a fingerprint sensing and identification device 20 with an antistatic structure according to a first embodiment of the present invention. The fingerprint sensing and identification device 20 with an antistatic structure is mainly composed of a substrate 22 , a sensing chip 32 and an electrostatic discharge protection circuit 30 .

Wherein, the substrate 22 is an integrally formed structure. In this embodiment, the upper surface of the substrate 22 is defined as a first surface, and the lower surface is defined as a second surface. The first surface of the substrate 22 is provided with a groove 24, and the sensor chip 32 is installed in the groove 24 for capturing images; the number of the groove 24 can be one or more, and one groove 24 is used as an example here . A plurality of conductive pads 28 are disposed on the second surface of the substrate 22 . In addition, a plurality of conductive pillars 26 are disposed around the groove 24 , the conductive pillars 26 penetrate the first surface and the second surface of the substrate 22 , and are in contact with the conductive pads 28 on the second surface. The electrostatic discharge protection circuit 30 is arranged on the first surface of the substrate 22 and surrounds the groove 24. At the same time, the electrostatic discharge protection circuit 30 is connected to the conductive column 26, so that the electrostatic discharge protection circuit 30 can be used as a channel for electrical connection. 30 can be electrically connected to the conductive pad 28 located on the second surface, so that the electrostatic discharge protection circuit 30 can conduct excess electrostatic charges and release them through the conductive pad 28, so as to prevent the sensing chip 32 from being damaged by static electricity and affecting the fingerprint sensor. Measure the accuracy of recognition.

In this embodiment, the substrate 22 can be an insulating substrate, preferably a ceramic substrate, such as High-Temperature Co-fired Ceramics (HTCC) or Low-Temperature Co-fired Ceramics (Low-Temperature Co-fired Ceramics, LTCC) alumina ceramic substrate. Therefore, to manufacture the electrostatic discharge protection circuit 30, the conductive column 26 and the conductive pad 28, the conductive material can be formed on the substrate 22 by means of electroplating, electroless plating or sputtering, and then the substrate 22 can be formed by pressure sintering. It is pressed and sintered together with the conductive pillar 26, the conductive pad 28 and the electrostatic discharge protection circuit 30, and then installed with the sensing chip 32, so that the packaging process of the fingerprint sensing and identification device is more streamlined.

FIG. 3 is a cross-sectional view of a fingerprint sensing and identification device 20 with an antistatic structure according to a first embodiment of the present invention. The above-mentioned fingerprint sensing and identification device 20 with an antistatic structure can be further packaged by covering the packaging adhesive layer 34 and the touch panel 36 . In this embodiment, the encapsulation adhesive layer 34 is filled in the groove 24 and surrounds the sensing chip 32 ; the material of the encapsulation adhesive layer 34 can be epoxy resin or silicone. In practice, the encapsulation adhesive layer 34 can also partially or completely cover the substrate 22 and the sensing chip 32 . Moreover, in this embodiment, the touchpad 36 covers the entire substrate 22 and exposes the electrostatic discharge protection circuit 30 to prevent static electricity; the touchpad 36 is usually made of glass. In actual implementation, the touchpad 36 only needs to cover at least the sensing chip 32 to protect the sensing chip 32 and serve as a user's finger contact interface. When the user's fingertips touch the touchpad 36, static electricity is generated, and then the electrostatic charge will be discharged to the outside of the substrate 22 through the conductive pad 28 after being conducted by the electrostatic discharge protection circuit 30, so as to avoid the touchpad 36 from being shocked by excessive static electricity. wear to protect the sensing chip 32, thereby improving the accuracy of fingerprint sensing and identification.

In addition, FIG. 4 is a perspective view of a fingerprint sensing and identification device 40 with an antistatic structure according to a second embodiment of the present invention. The fingerprint sensing and identification device 40 with an antistatic structure is mainly composed of a substrate 42 , a sensing chip 52 , a light emitting element 60 and an electrostatic discharge protection circuit 50 .

Wherein, the substrate 42 is an integrally formed structure. In this embodiment, the upper surface of the substrate 42 is defined as a first surface, and the lower surface is defined as a second surface. The first surface of the substrate 42 is provided with a first groove 44 and a second groove 58 , the sensor chip 52 is installed in the first groove 44 for capturing images, and the light emitting element 60 is installed in the second groove 58 , used as a light source; the light-emitting element 60 can be a light-emitting diode, preferably an infrared light-emitting diode. In addition, the number of second grooves 58 may be one or more, and one second groove 58 is taken as an example here, and the number of light emitting elements 60 may be one or more, and each light emitting element 60 is correspondingly arranged on each A second groove 58. In addition, a plurality of conductive pads 48 are formed on the second surface of the substrate 42, a plurality of conductive columns 46 are formed around the first groove 44 and the second groove 58, and the conductive columns 46 penetrate the first surface and the second surface of the substrate 42. The second surface is in contact with the conductive pad 48 on the second surface. The electrostatic discharge protection circuit 50 is arranged on the first surface of the substrate 42 and surrounds the first groove 44 and the second groove 58, and the electrostatic discharge protection circuit 50 is connected to the conductive column 46, so that the conductive column 46 can be used as an electrical The channel for the electrical connection enables the electrostatic discharge protection circuit 50 to be electrically connected to the conductive pad 48 on the second surface, so as to guide the excess electrostatic charge to be released to the outside, so as to achieve the purpose of electrostatic protection.

Same as the first embodiment, the substrate 42 of this embodiment can be an insulating substrate, preferably a ceramic substrate, such as an alumina ceramic substrate of high-temperature co-fired ceramics or low-temperature co-fired ceramics; thus, it is beneficial to pressurize and sinter the The substrate 42 is pressed and sintered together with the conductive pillars 46 , the conductive pads 48 and the ESD protection circuit 50 to shorten the packaging process.

Similarly, FIG. 5 is a cross-sectional view of a fingerprint sensing and identification device 40 with an antistatic structure according to a second embodiment of the present invention. The above-mentioned fingerprint sensing and identification device 40 with an antistatic structure can also be further packaged by covering the packaging adhesive layer 54 and the touch panel 56 . In this embodiment, the packaging adhesive layer 54 is filled in the first groove 44 and surrounds the sensing chip 52 , and at the same time, the packaging adhesive layer 54 is also filled in the second groove 58 and covers the light emitting element 60 ; The material of the encapsulation layer 54 can be epoxy resin or silicone. In actual implementation, the encapsulation adhesive layer 54 may partially or completely cover the substrate 42 , the sensing chip 52 and the light emitting element 60 . In addition, the touch panel 56 of this embodiment covers the entire substrate 42 and exposes the electrostatic discharge protection circuit 50 to prevent static electricity; the touch panel 56 is usually made of glass. In actual implementation, the touchpad 56 only needs to cover at least the sensing chip 52 to protect the sensing chip 52 and serve as a user's finger contact interface.

In the above embodiments, the ESD protection circuit is formed as a continuous ring circuit. In addition, the ESD protection circuit can also be a discontinuous ring circuit, for example, with one or more openings to provide different options for packaging design. .

In addition, the structure, quantity, and relative position of the conductive pillars used as the conductive channels in the present invention can be adjusted according to the required antistatic degree, for example, the number of conductive pillars can be one or more. In addition, the conductive pillar presented in the above-mentioned embodiment is in the form of a long cylindrical structure, and compared with the long cylindrical conductive pillar having a rectangular cross-section, the present invention also provides multiple implementations with different cross-sectional shapes, As shown in FIG. 6A , the conductive post 46 has a trapezoidal cross section with a narrow top and a wide bottom. As shown in FIG. 6B , the conductive post 46 has a trapezoidal cross section with a wide top and a narrow bottom. In actual implementation, the conductive pillars can not only be columnar structures with square or trapezoidal cross-sections, but also be cone-shaped, sheet-shaped, or irregularly shaped.

Of course, the conductive pads can also be adjusted and changed according to their structure, quantity, and relative position. As for the grooves, sensing chips, and the shapes, quantities, and relative positions of the light-emitting elements disclosed in the above embodiments, they are only examples and are not limited thereto. Anything that is equal to the spirit of this case does not depart from the present invention. category.

In summary, the fingerprint sensing and identification device with an antistatic structure provided by the present invention provides an integrally formed substrate, and integrates the electrostatic discharge protection circuit on the substrate, and then uses the conductive column as the electrostatic discharge protection circuit and the conductive pad circuit. The channel for permanent connection can guide the excess electrostatic charge out to achieve antistatic protection; further, the present invention can integrate the electrostatic discharge protection circuit, conductive column and conductive pad together in the manufacturing process of substrate forming, Compared with the prior art, not only the packaging structure can be effectively thinned, but also the packaging process can be simplified.

The above-described embodiments are only for illustrating the technical ideas and characteristics of the present invention, and its purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and should not limit the protection scope of the present invention with it. That is, all equivalent changes or modifications made according to the spirit disclosed in the present invention should still fall within the protection scope of the present invention.

Claims (9)

1. A fingerprint sensing identification device with an antistatic structure, characterized in that it comprises: A base plate has a first surface, a second surface and at least one conductive post passing through the first surface and the second surface, the first surface is integrally formed with a first groove, and the second surface is provided with at least one a conductive pad, and the conductive column is located around the first groove and is in contact with the conductive pad; A sensing chip is arranged in the first groove; and At least one electrostatic discharge protection circuit is disposed on the first surface and located around the first groove, and the electrostatic discharge protection circuit is in contact with the conductive column to electrically connect the conductive pad through the conductive column. 2. The fingerprint sensing and identification device with an antistatic structure according to claim 1, wherein the substrate is an insulating substrate. 3. The fingerprint sensing and identification device with an antistatic structure according to claim 2, wherein the insulating substrate is a ceramic substrate. 4 . The fingerprint sensing and identification device with an antistatic structure according to claim 1 , further comprising a packaging adhesive layer, the packaging adhesive layer at least filling the first groove. 5 . The fingerprint sensing and identification device with an antistatic structure according to claim 4 , wherein the encapsulating adhesive layer is epoxy resin or silica gel. 6 . 6 . The fingerprint sensing and identification device with an antistatic structure according to claim 4 , further comprising a touch panel, the touch panel at least covers the sensing chip and exposes the electrostatic discharge protection circuit. 7. The fingerprint sensing and identification device with an antistatic structure according to claim 1, wherein at least one second groove is integrally formed on the first surface of the substrate. 8. The fingerprint sensing and identification device with an antistatic structure according to claim 1, wherein the electrostatic discharge protection circuit is a continuous or discontinuous ring. 9. The fingerprint sensing and identification device with an antistatic structure according to claim 1, wherein the cross section of the conductive pillar is square or trapezoidal.