WO2022134838A1 - Packaging structure and packaging method - Google Patents

Abstract

Disclosed is a packaging structure, comprising: a chip unit, having opposing front and back sides, the front side thereof having a sensing region; a translucent cover panel, covering the front side of said chip unit; a plastic packaging layer, shielding the side wall of said translucent cover panel in a direction perpendicular to said sensing region and exposing the region opposite to the sensing region. Also disclosed by the present invention is packaging method. In the present solution, during the process of injection molding, the side wall of the translucent cover panel is shielded by means of the plastic packaging layer, thus preventing incident light reflection and interference with the sensing region and impact on imaging performance.

Description

Packaging structure and packaging method technical field

The invention belongs to the technical field of semiconductors, and in particular relates to a packaging structure and a packaging method.

Background technique

A photosensitive chip is an electronic device that senses external light and converts it into electrical signals. Photosensitive chips are usually fabricated using semiconductor manufacturing processes. After the photosensitive chip is fabricated, a series of packaging processes are performed on the photosensitive chip to form a packaged package structure for use in electronic devices such as digital cameras and digital video cameras.

The packaging structure of the photosensitive chip in the prior art includes a transparent cover plate, and the transparent cover plate is used to protect the optical area of the photosensitive chip and can transmit light.

However, in the specific use process of the existing photosensitive chip, the transparent cover plate has vertical sidewalls, and the sidewalls have the problem of incident light reflection. The reflected light of different angles will be reflected to the optical area, which will interfere with the effective direct light entering the optical area and affect the Imaging effect.

SUMMARY OF THE INVENTION

An embodiment of the present invention provides a packaging structure and method for solving the technical problems in the prior art that the sidewall of the light-transmitting cover plate reflects incident light, interferes with effective direct light entering the optical zone, and affects the imaging effect, including:

In one embodiment, a package structure includes:

A chip unit, with opposing front and back sides, the front side of which has a sensing area;

a light-transmitting cover plate covering the front side of the chip unit;

The plastic sealing layer shields the side wall of the light-transmitting cover plate from light in the direction perpendicular to the sensing area, and exposes the area opposite to the sensing area.

Preferably, in the above-mentioned packaging structure, the side wall of the light-transmitting cover plate is an inclined plane,

The plastic sealing layer is combined with the inclined surface.

Preferably, in the above-mentioned packaging structure, a step portion is formed on the peripheral edge of the light-transmitting cover plate,

The plastic encapsulation layer is filled on the stepped portion.

Preferably, in the above-mentioned packaging structure, the plastic sealing layer does not protrude from the surface of the light-transmitting cover plate facing away from the chip unit.

Preferably, in the above-mentioned packaging structure, the light-transmitting cover plate is supported on the surface of the chip unit by a supporting structure,

The sensing area is located in the cavity enclosed by the support structure.

Preferably, in the above-mentioned packaging structure, a circuit board is further included, and the back surface of the chip unit is attached and fixed on the circuit board,

The bonding pads of the chip unit and the circuit board are electrically connected through metal leads,

The plastic packaging layer is arranged on the surface of the circuit board on which the chip unit is fixed, and surrounds the chip unit and the metal leads.

Preferably, in the above-mentioned packaging structure, the light-transmitting cover plate is dry film, inorganic glass or organic glass.

In another embodiment, the present application also provides a packaging method for a packaging structure, including:

providing the chip unit;

Covering the front surface of the chip unit with a light-transmitting cover plate;

The chip unit and the light-transmitting cover plate are plastic-sealed, and the formed plastic-sealing layer shields the sidewall of the light-transmitting cover plate from light in the direction perpendicular to the sensing area, and exposes the area opposite to the sensing area.

In another embodiment, the present application also provides a packaging method for a packaging structure, including:

providing a wafer, the wafer has a plurality of the chip units;

A light-transmitting cover plate is provided, and the light-transmitting cover plate covers the front surface of the chip unit;

Through a cutting process, the wafer and the light-transmitting cover plate are cut to form a plurality of single-grain packaging structures;

The single-particle packaging structure is plastic-sealed, and the formed plastic-sealing layer shields the sidewall of the light-transmitting cover plate from light in a direction perpendicular to the sensing area, and exposes an area opposite to the sensing area.

Preferably, in the above-mentioned encapsulation method of the encapsulation structure, further comprising:

Adhere the multi-grain single-grain encapsulation structure to the circuit board, and then plastic-encapsulate the single-grain encapsulation structure;

And after plastic sealing, the circuit board is cut to form a plurality of single-particle packages.

Compared with the prior art, in this case, during the injection molding process, the side wall of the light-transmitting cover plate is shielded by the plastic sealing layer, so as to avoid the reflection of incident light, interfere with the sensing area, and affect the imaging effect.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments described in this application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

1 is a cross-sectional view of a package structure in Embodiment 1 of the present application;

2 is a cross-sectional view of a package structure in Embodiment 2 of the present application;

3 to 8 are schematic diagrams of intermediate structures formed by the packaging structure in Embodiment 1 of the present application.

Detailed ways

The present invention will be more fully understood from the following detailed description, which should be read in conjunction with the accompanying drawings. Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and for teaching one skilled in the art to vary in virtually any suitable detailed embodiment. The manner adopts the representative basis of the present invention.

With reference to FIG. 1 , in an embodiment of the present application, a package structure 10 is provided, including a chip unit 11 , a light-transmitting cover plate 12 , a circuit board 13 and a plastic sealing layer 16 .

Referring to FIG. 4 , the chip unit 11 has opposite front surfaces 111 and back surfaces 112 , the front surface has a sensing area 113 , and the front surface 111 of the chip unit 11 is provided with pads 114 located outside the sensing area 113 .

The chip unit 11 is a photosensitive chip, which may be a fingerprint sensor chip, an image sensor chip, or the like.

The light-transmitting cover plate 12 covers the front surface 111 of the chip unit 11 for protecting the front surface of the chip unit 11 to be packaged. Since light needs to pass through the light-transmitting cover plate 12 to reach the sensing area 113 , the light-transmitting cover plate 12 has high light transmittance and is a light-transmitting material. Both surfaces of the light-transmitting cover plate 12 are flat and smooth, and will not cause scattering or diffuse reflection of incident light.

Specifically, the material of the light-transmitting cover plate 12 may be dry film, inorganic glass, plexiglass or other light-transmitting materials with specific strength, and the transmittance needs to reach more than 92%.

In one embodiment, the light-transmitting cover plate 12 is supported on the front surface of the chip unit 11 by the support structure 14 , a cavity 114 is enclosed between the support structure 14 , the light-transmitting cover plate 12 and the chip unit 11 , and the sensing area 113 is formed in the inside the cavity 114 .

In another embodiment, the light-transmitting cover plate 12 can also be pasted and fixed with the chip unit through an optical adhesive layer (not shown), and the optical adhesive layer has high light transmittance. In this embodiment, an encapsulation structure that can form no cavity is adopted, and the plastic encapsulation mold can directly act on the transparent cover plate.

The circuit board 13 is used to connect external circuits. The backside of the chip unit 11 is glued to one surface of the circuit board 13 , and the other surface of the circuit board 13 is provided with solder balls 131 electrically connected to the external circuit. The bonding pads 114 of the chip unit 11 and the circuit board 13 are electrically connected through metal leads 15 .

In another embodiment, the connection between the pads and the outside can also be realized by means of through silicon vias. Specifically, the chip unit 11 is further provided with: through holes extending from the back side 112 of the chip unit 11 to the front side 111 (not shown in the figure). shown), the through hole exposes the pad 114, the pad 114 is electrically connected to the solder ball 131 through a metal wiring layer (not shown), and the chip unit 11 and other external circuits are electrically connected by the solder ball 131 and other external circuits. electrical connection.

The plastic sealing layer 16 is formed by injection molding, which shields the sidewall of the light-transmitting cover plate 12 in the direction perpendicular to the sensing area 113 and exposes the area opposite to the sensing area 113 .

In this case, the plastic sealing layer 16 shields the side wall of the light-transmitting cover plate 12 , which can minimize the incidence of external light on the side wall of the light-transmitting cover plate 12 . At the same time, the plastic encapsulation layer 16 also surrounds the pads 114 and the metal leads 15 .

As long as the plastic sealing layer 16 can cover the side wall 121 of the light-transmitting cover plate 12 , it can play a role of reflecting the light incident on the side wall 121 of the light-transmitting cover plate 12 .

The material of the plastic sealing layer 16 may be epoxy resin molding compound. In particular, in order to increase the reflection and absorption of light by the plastic encapsulation layer 16, optionally, the plastic encapsulation layer 16 is a black plastic encapsulation layer.

In order to improve the encapsulation effect, the plastic encapsulation layer 16 does not protrude from the surface of the transparent cover plate away from the chip unit. In a preferred embodiment, the surface of the plastic encapsulation layer and the light incident surface of the transparent cover plate are located on the same plane.

In order to achieve the above purpose, satisfy the shading effect, and not increase the cost of injection molding, as shown in FIG. 1 , in the first embodiment, the side wall 121 of the light-transmitting cover plate 12 is an inclined plane, and the inclined plane is along the vertical direction away from the photosensitive chip. direction, gradually approaching the sensing area 113 .

In the first embodiment, the specific position of the projected edge of the plastic sealing layer 16 on the chip unit 11 is not limited. The more inclined the side wall 121 of the cover plate 12 is, the less light is incident on the side wall 121 of the light-transmitting cover plate 12 . Therefore, in this embodiment, the projection of the plastic encapsulation layer 16 on the chip unit 11 is toward the edge of the sensing area 113 and is far from the sensing area. The closer the edge of 113 is, the better.

Referring to FIG. 2 , in the second embodiment, a stepped portion 122 is formed on the peripheral edge of the light-transmitting cover plate 12 , and the plastic sealing layer 16 is filled on the stepped portion 122 . cover the face.

In the second embodiment, the specific position of the projected edge of the plastic sealing layer 16 on the chip unit 11 is not limited. The longer the length of 122 in the horizontal direction, the less light is incident on the side wall 121 of the light-transmitting cover plate 12 .

It should be noted that, the thickness of the step portion 122 in the direction perpendicular to the photosensitive region 113 should be as small as possible.

Correspondingly, an embodiment of the present invention provides a packaging method for forming a packaging structure as shown in FIG. 1 . Please refer to FIG. 3 to FIG. 7 , which are schematic diagrams of intermediate structures formed during the packaging process of the packaging method according to the embodiment of the present invention.

Step s1 : Referring to FIGS. 3 and 4 , provide a wafer to be packaged, wherein FIG. 3 is a schematic top view of the wafer to be packaged, and FIG. 4 is a cross-sectional view along A-A of FIG. 3 (a single chip unit is an example).

The wafer to be packaged has a front side 111 and a back side 112 opposite the front side 111 . The wafer 100 includes a plurality of chip units 11 arranged in an array. There are dicing channels 110 between adjacent chip units 11 to facilitate dicing in the subsequent dicing process.

The front surface 111 includes a sensing area 113 and a non-sensing area surrounding the sensing area, and a pad 114 is disposed in the non-sensing area.

It should be noted that the cutting channel 110 between two adjacent chip units 11 is only a blank area reserved for cutting between the two chip units 11 , and the cutting channel 110 is connected to the chip units 11 on both sides. There is no actual boundary line in between.

Step s2 : as shown in FIG. 5 , a light-transmitting cover plate 12 is provided, a plurality of supporting structures 14 are formed on a surface of the light-transmitting cover plate 12 , and then the supporting structures 14 and the front surface 111 of the chip unit 11 are bonded combine.

Step s3 : as shown in FIG. 6 , the bonding pads 114 on the chip unit 11 are exposed by cutting or cutting and etching, and then the wafer 100 is divided by the cutting process. When cutting, along the cutting channel 110 The cutting is carried out in the direction to form a plurality of package structures 10 . The wafer 100 can be cut by a dicing knife or a laser, and the dicing knife can be cut by a metal knife or a resin knife.

Wherein, the light-transmitting cover plate may be cut by a special-shaped blade to form the inclined side wall 121 shown in FIG. 1 .

The light-transmitting cover plate can be cut by blades of different widths to form the stepped portion 122 structure shown in FIG. 2 .

Step s4 : as shown in FIG. 7 , a circuit board 13 is provided, and the circuit board 13 has opposite front and back. The front side is used to fix the chip unit 11 . Specifically, the back side of the chip unit 11 is arranged to face the front side of the circuit board 13 . The backside of the circuit board 13 has solder balls 131 , and the solder balls 131 are used for connection with external circuits. An interconnection circuit is provided in the circuit board 13 , and the interconnection circuit is connected to the solder balls 131 .

The chip unit 11 and the circuit board 13 can be fixed by bonding through an adhesive layer, or fixed by welding through a welding process.

Then, the chip unit 11 is electrically connected to the circuit board 13 through metal leads 15 .

Wherein, the electrical connection between the chip unit 11 and the circuit board 13 is not limited to the connection of the metal leads 15 . An interconnection structure may also be formed on the surface of the chip unit 11 through a TSV (through silicon via) process, and the electrical connection of the circuit board 13 is directly performed through the interconnection structure.

Step s5 : as shown in FIG. 8 , injection molding is performed on the sidewall of the light-transmitting cover plate, the exposed pads 114 and the metal leads 15 .

Step s6: The circuit board 13 is cut and divided into individual packages, as shown in FIG. 1 and FIG. 2 .

The aspects, embodiments, features, and examples of the present invention are to be considered in all respects illustrative and not intended to limit the invention, the scope of which is defined only by the claims. Other embodiments, modifications, and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.

The use of the terms "include, includes, including," "have, has, or having" should generally be understood to be open-ended and not limiting unless specifically stated otherwise.

The use of the singular herein includes the plural (and vice versa) unless specifically stated otherwise. Also, the singular forms "a (a, an)" and "the (the)" include the plural forms unless the context clearly dictates otherwise. Additionally, where the use of the term "about" precedes a magnitude, the teachings of the present invention also include the particular magnitude itself, unless specifically stated otherwise.

It should be understood that the order of the steps or the order in which the particular actions are performed is not critical so long as the present teachings remain operable. Furthermore, two or more steps or actions may be performed simultaneously.

Although the present invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions and/or additions and the like may be made without departing from the spirit and scope of the invention Effects replace elements of the described embodiments. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is not intended herein to limit the invention to the particular embodiments disclosed for carrying out the invention, but it is intended that this invention include all embodiments falling within the scope of the appended claims. Furthermore, unless specifically stated, any use of the terms first, second, etc. does not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another.

Claims (10)

A package structure, characterized in that, comprising: A chip unit, with opposing front and back sides, the front side of which has a sensing area; a light-transmitting cover plate covering the front side of the chip unit; The plastic sealing layer shields the side wall of the light-transmitting cover plate from light in the direction perpendicular to the sensing area, and exposes the area opposite to the sensing area. The packaging structure according to claim 1, wherein the side wall of the light-transmitting cover plate is an inclined plane, The plastic sealing layer is combined with the inclined surface. The packaging structure according to claim 1, wherein a step portion is formed on the peripheral edge of the light-transmitting cover plate, The plastic encapsulation layer is filled on the stepped portion. The packaging structure according to claim 1, wherein the plastic sealing layer does not protrude from the surface of the light-transmitting cover plate facing away from the chip unit. The package structure according to claim 1, wherein the light-transmitting cover plate is supported on the surface of the chip unit by a support structure, The sensing area is located in the cavity enclosed by the support structure. The package structure according to claim 1, further comprising a circuit board, the back of the chip unit is attached and fixed on the circuit board, The bonding pads of the chip unit and the circuit board are electrically connected through metal leads, The plastic packaging layer is arranged on the surface of the circuit board on which the chip unit is fixed, and surrounds the chip unit and the metal leads. The package structure according to claim 1, wherein the light-transmitting cover plate is dry film, inorganic glass or organic glass. A packaging method for forming the packaging structure according to any one of claims 1-7, characterized in that, comprising: providing the chip unit; Covering the front surface of the chip unit with a light-transmitting cover plate; The chip unit and the light-transmitting cover plate are plastic-sealed, and the formed plastic-sealing layer shields the sidewall of the light-transmitting cover plate from light in the direction perpendicular to the sensing area, and exposes the area opposite to the sensing area. A packaging method for forming the packaging structure according to any one of claims 1-7, characterized in that, comprising: providing a wafer, the wafer has a plurality of the chip units; A light-transmitting cover plate is provided, and the light-transmitting cover plate covers the front surface of the chip unit; Through a cutting process, the wafer and the light-transmitting cover plate are cut to form a plurality of single-grain packaging structures; The single-particle packaging structure is plastic-sealed, and the formed plastic-sealing layer shields the sidewall of the light-transmitting cover plate from light in a direction perpendicular to the sensing area, and exposes an area opposite to the sensing area. The packaging method of the packaging structure according to claim 9, further comprising: Adhere the multi-grain single-grain encapsulation structure to the circuit board, and then plastic-encapsulate the single-grain encapsulation structure; And after plastic sealing, the circuit board is cut to form a plurality of single-particle packages.

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