CN107545246A - A kind of encapsulating structure and its method for packing of fingerprint recognition chip - Google Patents

Abstract

The invention discloses a packaging structure of a fingerprint identification chip and a packaging method thereof, comprising a fingerprint identification chip, the fingerprint identification chip includes a first surface and a second surface; Electrically connected pads; a number of conductive terminals and grooves are provided on the second surface; through-silicon holes are provided on the grooves, and the through-silicon holes expose the pads on the first surface; the pads pass through the through-silicon holes and the grooves The metal circuit on the side wall is electrically connected to the conductive terminal; wherein the fingerprint recognition chip is surrounded by a second plastic package and the outside of the second surface, and the second plastic package exposes the conductive terminal; the second plastic package and the outside of the first surface are wrapped There is a first plastic package. The encapsulation structure has plastic encapsulation protection, and the fingerprint recognition chip is provided with through-silicon holes, so that the encapsulation structure is thinner. Compared with the existing structure, the encapsulation structure has reduced thickness and lower cost.

Description

Packaging structure and packaging method of a fingerprint identification chip

technical field

The invention belongs to the technical field of identification, and in particular relates to a packaging mechanism of a fingerprint identification chip and a packaging method thereof.

Background technique

Fingerprint sensors can be built into electronic devices, such as laptops, tablet computers, smart phones, etc., by reading the user's fingerprint pattern, the device can be unlocked by the authorized user of the device through the authentication of the authorized user's fingerprint pattern, greatly improving Safety of Electronic Devices.

The fingerprint sensor is characterized in that there is a sensing area on the surface of the fingerprint sensor chip, and this area interacts with the external stimulus to be identified to generate an electrical signal that the chip can identify and process. The distance between this area and external stimuli should be as short as possible so that the generated signal can be detected. In many current chip technologies, the chip pads are generally located on the same surface. If the chip pads are led out by bonding wires, the height of the bonding wires will inevitably increase the distance between the sensing area and the outside of the package. In order to solve the problem that the bonding wire is higher than the surface of the sensor chip and affects the performance of the sensor.

The patent number is CN201420009042, and the utility model titled wafer-level packaging structure and fingerprint identification device proposes a step made on the edge of the sensor chip, leading the pad on the chip surface to the step through the conductive layer, and then proceeding hit the line. In the literature with the patent number US20140285263A1, the sensing area is formed on the silicon substrate by deposition technology, and there is a slope on the edge of the silicon substrate, so that the electrical signal generated by the sensing area can be extracted through the conductive layer.

The technical solutions of the above two patents are to make steps on the front of the sensor chip, then wire bonding, the chip and the substrate are electrically connected through metal wires, and finally plastic-packed and cut into a fingerprint sensor. Since the substrate has a certain thickness, the fingerprint sensor cannot be made thinner.

Contents of the invention

The invention provides a packaging structure of a fingerprint recognition chip, the packaging structure has two layers of plastic packaging, and the fingerprint recognition chip is provided with through-silicon holes, so that the packaging structure is thinner. Compared with the existing structure, the packaging structure has a thickness of reduced and less costly.

The present invention also provides a method for encapsulating the fingerprint identification chip. In the method, the above-mentioned encapsulation structure of the fingerprint identification chip is obtained by performing plastic encapsulation twice. The encapsulation structure is thinner and lighter.

The technical solution of the present invention is: a packaging structure of a fingerprint identification chip, including a fingerprint identification chip, the fingerprint identification chip includes a first surface and a second surface; a fingerprint sensing area is arranged on the first surface, and the fingerprint sensing area is electrically connected The second surface is provided with a number of conductive terminals and grooves; the groove is provided with through-silicon holes, and the through-silicon holes expose the pads on the first surface; The metal circuit on the wall is electrically connected to the conductive terminal; wherein the fingerprint identification chip is surrounded by a second plastic package and the outside of the second surface, and the second plastic package exposes the conductive terminal; the second plastic package and the outside of the first surface are wrapped with The first plastic body.

Furthermore, the present invention is characterized in that:

Wherein the side of the second plastic package is wrapped inside the first plastic package.

Wherein the side of the second plastic package is exposed and flush with the side of the first plastic package.

Wherein the thickness of the first plastic package on the first surface is 50-100 μm.

Wherein the groove includes a first inclined surface obliquely downward along the second surface, the bottom of the first inclined surface is set as a horizontal bottom surface of the groove; and the TSV is arranged on the bottom surface of the groove.

Another technical solution of the present invention is: a packaging method for a fingerprint identification chip, comprising the following steps:

Step 1, paste the adhesive film on the carrier board, mount the first surface of the fingerprint identification chip with the fingerprint sensing area on the adhesive film, and make the second surface face up;

Step 2, plastic-encapsulating the mounted fingerprint identification chip; specifically, using plastic packaging material to fill the surrounding area of the fingerprint identification chip and above the second surface to obtain a second plastic package;

Step 3, grinding the second plastic package to expose the conductive terminals;

Step 4, separate the adhesive film from the fingerprint identification chip at 200°C, reset the adhesive film on the carrier board, and then mount the second surface with conductive terminals in step 3 on the adhesive film so that the first surface faces set on;

Step 5, using a plastic packaging material to perform plastic packaging on the first surface of the fingerprint recognition chip and the outside of the second plastic package to obtain the first plastic package;

Step 6, separating the adhesive film in an environment of 200°C to obtain the packaging structure of the fingerprint identification chip;

Step 7, cutting the packaged product to obtain a circular, oval, rectangular or waist-shaped single package structure.

Furthermore, the present invention is characterized in that:

Wherein step 5, after grinding the part of the first plastic package on the first surface to 50-100 μm, the encapsulation structure is obtained.

In step 5, the first plastic package is cut so that the first plastic package has a square structure.

In step 5, the first plastic package is cut, so that the side of the second plastic package is exposed, and the side of the second plastic package is aligned with the side of the first plastic package.

Wherein the dielectric constant of the molding material used in step 2 and step 3 is 3-5 or 7-25.

Compared with the prior art, the beneficial effect of the present invention is that the packaging structure is a secondary plastic packaging structure for the fingerprint recognition chip, compared with the existing packaging structure of primary plastic packaging, the packaging structure saves the use of the substrate, thereby The thickness of the packaging structure is reduced, and the fingerprint identification chip is used; wherein the second plastic package is used to package the gap around the fingerprint identification chip and between the conductive terminals, and the first plastic package is used to package the second plastic package and the second plastic package of the fingerprint identification chip. a surface.

Furthermore, the side of the second plastic package is exposed, which can reduce the volume of the packaging structure.

Furthermore, the thickness of the first plastic package is smaller, so that the thickness of the packaging structure can be reduced.

Furthermore, the groove composed of the first slope and the bottom surface of the groove is used to etch the TSV, and defines the optimal etching angle and size of the groove; the first slope and the horizontal groove are first etched on the groove The bottom surface can prevent the etched part from breaking, so as to facilitate further etching of the TSV.

The beneficial effect of the present invention is also that: the method performs plastic sealing on the fingerprint recognition chip twice, and firstly uses the cutting board and the adhesive film to fix the fingerprint recognition chip, avoids the use of the substrate, and realizes the packaging of the fingerprint recognition chip. The second plastic package and the first plastic package are packaged with the surface of the chip, thereby reducing the use of plastic packaging materials and reducing the thickness of the packaging structure.

Furthermore, after the first plastic package is packaged, the first plastic package is ground to reduce the volume of the packaging structure.

Furthermore, the first plastic package is cut to make the volume of the plastic package smaller.

Furthermore, the range of plastic packaging materials used is relatively large, and more different types of plastic packaging materials can be used for packaging, and the applicability is wider.

The thickness of the fingerprint recognition chip packaging structure obtained by the method can reach 0.3mm or less than 0.3mm, and compared with the existing fingerprint recognition chip packaging structure, the thickness is smaller and lighter.

Description of drawings

Fig. 1 is a kind of structural representation of the present invention;

Fig. 2 is another kind of structural representation of the present invention;

Fig. 3 is the structural representation of mounting in the present invention;

4 is a schematic structural view of the second plastic package in the present invention;

FIG. 5 is a schematic structural view of the first plastic package in the present invention.

In the figure, 1 is the first plastic package; 2 is the second plastic package; 3 is the conductive terminal; 4 is the fingerprint identification chip; 5 is the groove; 6 is the adhesive film; 7 is the carrier board; 8 is the first slope; 9 10 is the through-silicon via; 11 is the fingerprint sensing area; 12 is the pad; 13 is the first surface; 14 is the second surface.

detailed description

The technical solution of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

The present invention provides a packaging structure of a fingerprint identification chip, as shown in Figure 1, including a fingerprint identification chip 4; the fingerprint identification chip 4 includes a first surface 13 and a second surface 14, and the first surface 13 is provided with a fingerprint sensor The area 11 and the pad 12 are electrically connected between the fingerprint sensing area 11 and the pad 12, a number of conductive terminals 3 are provided on the second surface 14, and the end of the second surface 14 is provided with a groove 5 by etching, The groove 5 includes a first bevel 8 etched obliquely downward along the second surface 14, wherein the inclination angle of the first bevel 8 is 60-70°, preferably 65°, and the vertical depth of the groove 5 is 60-100 μm. Preferably 80 μm, the bottom of the first slope 8 is provided with an etched horizontal groove bottom 9, the length of the groove bottom 9 is 240-250 μm, preferably 245 μm; The hole 10, the depth of the through-silicon hole 10 is 55-65 μm, preferably 60 μm; the end of the through-silicon hole 10 with a large diameter is arranged on the bottom surface 9 of the groove, and the diameter is 100-105 μm, preferably 104 μm; the diameter of the through-silicon hole 10 is small One end of is disposed on the first surface 13 and has a diameter of 55-65 μm, preferably 60 μm. And the TSV 10 is facing the pad 12 at the position of the first surface 13 , and the pad 12 is electrically connected to the conductive terminal 3 through the TSV 10 and the groove 5 .

As shown in Figure 1, the outer side of the fingerprint identification chip 4 is wrapped with a cube-shaped packaging structure, and the packaging structure includes a first plastic package 1 and a second plastic package 2; wherein the second plastic package 2 is wrapped on the side of the fingerprint identification chip 4 and the second surface 14, and the second plastic package body 2 exposes the first surface 13 and the conductive terminal 3; the first plastic package body 1 wraps the outside of the second plastic package body 2, and the first plastic package body 1 wraps the first surface 13 and the The side of the second plastic package 2; the packaging structure exposes the power-off terminal 3.

As shown in Figure 2, the outer side of the fingerprint identification chip 4 is wrapped with a cube-shaped packaging structure, and the packaging structure includes a first plastic package 1 and a second plastic package 2; wherein the second plastic package 2 is wrapped on the side of the fingerprint identification chip 4 and the second surface 14, and the second plastic package 2 exposes the first surface 13 and the conductive terminal 3; the first plastic package 1 is wrapped on the first surface 13, and the side of the first plastic package 1 and the second plastic package The sides of the 2 are set flush.

The side surfaces of the second plastic package 2 and the first plastic package 1 can be multiple planes or curved surfaces; that is, the cross-sections of the first plastic package 1 and the second plastic package 2 are polygonal, or elliptical, or circular, etc. structure.

The molding materials used in the first plastic package 1 and the second plastic package 2 of the package structure are all plastic packaging materials with a dielectric constant of 3-5 or 7-25, and the higher the dielectric constant, the higher the fingerprint identification performance. The better it is, the molding material with a dielectric constant of 7 is preferred. Moreover, the thickness of the first plastic package 1 is 50-100 μm, and the total thickness of the packaging structure is less than 0.3 mm.

When the fingerprint identification chip 4 adopts FPC or the fingerprint chip algorithm of Goodix Technology, the first plastic package 1 and the second plastic package 2 both use plastic packaging materials with a dielectric constant of 3-5; when the fingerprint identification chip uses other fingerprint chip algorithms , both the first plastic package and the second plastic package use plastic packaging materials with a dielectric constant of 7-25.

The present invention also provides a packaging method for a fingerprint recognition chip, comprising the following steps:

Step 1, as shown in Figure 3, paste the adhesive film 6 on the carrier 7, wherein the adhesive film 6 is a thermal separation film of epoxy resin material, and the carrier 7 is made of steel or other metal materials, or tempered glass Then the first surface 13 of the fingerprint recognition chip 4 is pasted on the adhesive film 6, wherein the fingerprint sensing area 11 of the fingerprint recognition chip 4 is adhered to the adhesive film 6, and the second surface 14 is set upwards to complete the fingerprint identification chip. mount.

Step 2, as shown in Figure 4, carries out bare chip packaging to the fingerprint identification chip 4 that has been mounted; -25 of the plastic packaging material to obtain the second plastic packaging body 2. The second plastic package body 2 is a plastic package material filled around the fingerprint recognition chip 4 and between the conductive terminals 3 , and is connected as a whole.

Step 3, grinding the part of the second plastic package 2 above the second surface 14 to expose all the conductive terminals 3 .

Step 4, as shown in Figure 5, on the basis of step 3, at a temperature of 200 degrees Celsius, the adhesive film 6 is thermally separated, and the adhesive film 6 is reinstalled on the carrier plate 7, and then the polished second The surface 14 is mounted on the adhesive film 6, so that the conductive terminal 3 is pasted on the adhesive film 6, and the first surface 13 is set upward;

Step 5, use a plastic packaging material with a dielectric constant of 3-5 or 7-25 to plastic seal the surroundings of the second plastic package 2 and the top of the first surface 13 to obtain the first plastic package 1, and the first plastic package 1 wraps the second plastic package. Two plastic package body 2 and the first surface 13 .

Step 6: Grinding the part of the first plastic package 1 above the first surface 13 until the thickness of the first plastic package 1 is 50-100 μm; then cutting to obtain a cube-shaped packaging structure. After cutting, the second The side of the plastic package 2 is exposed, and the side of the second plastic package 2 is flush with the side of the first plastic package 1 .

Step 7, place the packaging structure in an environment of 200°C, separate the adhesive film 6 from the second surface 14, and obtain the finished package, the thickness of the packaging structure is less than 0.3mm;

Step 8, cutting the packaged product to obtain a circular, oval, rectangular or waist-shaped single package structure.

The embodiment of the encapsulation method of fingerprint recognition chip of the present invention is:

Example 1

This embodiment uses a fingerprint identification chip, and the chip uses an FPC fingerprint chip algorithm.

First paste a thermal separation film on a steel carrier plate, then mount the first surface 13 of the fingerprint identification chip 4 on the thermal separation film, and the second surface 14 with the conductive terminal 3 faces upward; then use the dielectric constant Plastic sealing material of 4 is plastic-sealed around the fingerprint recognition chip 4 and on the second surface 14 to obtain the second plastic packaging body 2, and then the second plastic packaging body 2 is ground to expose all the conductive terminals 3; and then at 200°C The adhesive film 6 is thermally separated under the environment, and the adhesive film is pasted again on the carrier plate 7, and the second surface 14 is pasted on the adhesive film, so that the first surface 13 is set upward; then on the first surface 13 and The surroundings of the second plastic package 2 are plastic-sealed with a plastic packaging material with a dielectric constant of 4 to obtain the first plastic package 1; finally, the first plastic package is ground with a grinding machine to 50 μm, and cut, as shown in the figure 2, the side of the second plastic package 2 is exposed, and the side of the second plastic package 2 is flush with the side of the first plastic package 1; then the second surface 14 is separated from the heat at 200°C The film is separated, and finally a packaged product with a thickness of 0.30mm is obtained, and then the packaged product is cut to obtain a circular or oval single package structure.

Example 2

This embodiment adopts a fingerprint identification chip, and the chip adopts the fingerprint chip algorithm of Goodix Technology.

First, stick a thermal separation film on a carrier made of stainless steel, then mount the fingerprint identification chip 4 on the thermal separation film so that the second surface 14 faces upward; then use a mold to closely adhere to the first surface 13; and use the medium A plastic packaging material with an electrical constant of 3 is plastic-sealed around the fingerprint identification chip 4 and between the conductive terminals to obtain a second plastic package 2, and then the second plastic package 2 is ground to expose all the conductive terminals 3; and then heated at 200°C The adhesive film 6 is thermally separated under the environment, and the adhesive film is pasted again on the carrier plate 7, and the second surface 14 is pasted on the adhesive film, so that the first surface 13 is set upward; then the first surface 13 and the second surface The side of the second plastic package 2 is plastic-sealed with a plastic packaging material with a dielectric constant of 5 to obtain the first plastic package; finally, the first plastic package 1 is ground with a grinder until it reaches 60 μm, and then cut, as shown in the figure 1, make the first plastic package 1 wrap the second plastic package 2; then in the environment of 200°C, separate the second surface 14 from the thermal separation film, and finally obtain a packaged product with a thickness of less than 0.30mm, and then package the finished product Cutting is performed to obtain a rectangular single-chip package structure.

Example 3

This embodiment uses a fingerprint recognition chip, and the chip uses a common fingerprint chip algorithm.

First, stick a thermal separation film on a carrier made of stainless steel, then mount the fingerprint identification chip 4 on the thermal separation film so that the second surface 14 faces upward; then use a mold with a protective soft layer to closely adhere to the first surface 13 and use a plastic packaging material with a dielectric constant of 7 to perform plastic packaging around the fingerprint recognition chip and between the conductive terminals to obtain a second plastic package, and then grind the second plastic package 2 to expose all the conductive terminals 3; then Thermally separate the adhesive film 6 under an environment of 200°C, and re-paste the adhesive film on the carrier plate 7, and paste the second surface 14 on the adhesive film, so that the first surface 13 is set upward; then on the first surface 13 and the second plastic package 2 are molded with a plastic packaging material with a dielectric constant of 7 to obtain the first plastic package 1; finally, the first plastic package 1 is ground with a grinding machine to 100 μm, and then the packaging structure is cut Then, under the environment of 200°C, the second surface 14 is detached from the thermal separation film, and finally a finished package with a thickness of 0.30 mm is obtained, and then the finished package is cut to obtain a waist-shaped single package structure.

Claims (10)

1. a kind of encapsulating structure of fingerprint recognition chip, it is characterised in that including fingerprint recognition chip (4), fingerprint recognition chip (4) first surface (13) and second surface (14) are included；Fingerprint sensing area (11) is provided with first surface (13), with fingerprint sense Survey the pad (12) that area (11) are electrically connected with；Some conducting terminals (3) and groove (5) are provided with second surface (14)；Groove (5) silicon hole (10) is provided with, silicon hole (10) exposes the pad (12) on first surface (13)；Pad (12) is led to by silicon Metallic circuit on hole (10) and groove (5) side wall is electrically connected with conducting terminal (3)；

The second plastic-sealed body (2), the second plastic-sealed body are enclosed with the outside of the surrounding and second surface (14) of the fingerprint recognition chip (4) (2) make conducting terminal (3) exposed；The first plastic-sealed body (1) is enclosed with the outside of second plastic-sealed body (2) and first surface (13).

2. the encapsulating structure of fingerprint recognition chip according to claim 1, it is characterised in that second plastic-sealed body (2) Side wrap it is internal in the first plastic-sealed body (1).

3. the encapsulating structure of fingerprint recognition chip according to claim 1, it is characterised in that second plastic-sealed body (2) Side it is exposed, and flushed with the side of the first plastic-sealed body (1).

4. the encapsulating structure of the fingerprint recognition chip according to claim 1-3 any one, it is characterised in that described first Thickness of the plastic-sealed body (1) on first surface (13) is 50-100 μm.

5. the encapsulating structure of the fingerprint recognition chip according to claim 1-3 any one, it is characterised in that the groove (5) the first inclined-plane (8) along second surface (14) obliquely is included, the bottom of the first inclined-plane (8) is arranged to horizontal groove-bottom Face (9)；And silicon hole (10) is arranged in groove floor (9).

6. a kind of method for packing of fingerprint recognition chip, it is characterised in that comprise the following steps：

Step 1, glued membrane (6) is pasted on support plate (7), the first table that fingerprint recognition chip (4) is had to fingerprint sensing area (11) Face (13) is mounted on glued membrane (6), while makes second surface (14) upward；

Step 2, plastic packaging is carried out to the fingerprint recognition chip (4) for completing attachment；It is specific to be filled in fingerprint knowledge using capsulation material Above the surrounding and second surface (14) of other chip (4), the second plastic-sealed body (2) is obtained；

Step 3, the second plastic-sealed body (2) is ground, makes conducting terminal (3) exposed；

Step 4, glued membrane (6) is separated with fingerprint recognition chip (4) under 200 DEG C of environment, glued membrane is reset on support plate (7) (6), then the second surface (14) for having conducting terminal (3) in step 3 is mounted on glued membrane (6), makes first surface (13) Set upward；

Step 5, entered using capsulation material on the outside of the first surface (13) and the second plastic-sealed body (2) of fingerprint recognition chip (4) Row plastic packaging, obtain the first plastic-sealed body (1)；

Step 6, glued membrane is separated in the environment of 200 DEG C, obtains the encapsulation finished product of fingerprint recognition chip；

Step 7, encapsulation finished product is cut, obtains single encapsulating structure of circular, ellipse, rectangle or waist-hole type.

7. the method for packing of fingerprint recognition chip according to claim 6, it is characterised in that by first in the step 5 Plastic-sealed body (1) is located at the partial mill on first surface (13) to after 50-100 μm, obtains encapsulating structure.

8. the method for packing of fingerprint recognition chip according to claim 6, it is characterised in that to first in the step 5 Plastic-sealed body (1) is cut, and it is cube shape structure to make the first plastic-sealed body (1).

9. the method for packing of the fingerprint recognition chip according to right wants 7 or 8 any one, it is characterised in that the step 5 In the first plastic-sealed body (1) is cut, make the side of the second plastic-sealed body (2) exposed, and the side of the second plastic-sealed body (2) and the The side alignment of one plastic-sealed body (1).

10. the method for packing of fingerprint recognition chip according to claim 6, it is characterised in that the step 2 and step 3 The dielectric constant of the middle capsulation material used is 3-5 or 7-25.