Fan-out packaging structure and manufacturing process of a lens structure optical sensor chip

Abstract

The application provides a fan-out packaging structure and manufacturing process of a lens structure optical sensor chip, which meets the performance and packaging structure of the photosensitive chip packaging requirement, and greatly reduces the packaging cost. The application comprises: a chip, which is an optical sensor chip, an upper surface area of the chip is provided with a solder pad and a photosensitive area; a plastic packaging layer; a black insulating layer, a lower surface of the black insulating layer is provided with a plurality of concave metal solder pads, and the lower surface of the metal solder pad is provided with an exposed metal tin layer; a protective glue layer, which is transparent; a first metal wiring layer; and a second metal wiring layer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chip packaging, in particular to a fan-out packaging structure of a lens structure optical sensor chip, and also provides a manufacturing process of the fan-out packaging structure. BACKGROUND

[0002] As a new advanced packaging form, the plate fan-out packaging has been favored by packaging enterprises in terms of cost. With the development of packaging technology, especially the standardization and localization of equipment and materials, the plate fan-out packaging is increasingly applied in various fields related to traditional packaging. At present, it has been successfully applied in power management, motor drive, audio and video sensor integrated circuit products, but it has rarely been involved in optical products, especially in optical sensing chips with lens structure. Due to the special structure of the optical sensing chip, which has a photosensitive area and an external corresponding arc lens, the traditional packaging has the following two requirements for packaging such products. First, high-transmittance plastic packaging materials must be used to ensure that the chip is exposed and the photosensitive area is not blocked. Since the plastic packaging mold is customized, the lens structure that meets the requirements is formed in the photosensitive area. Second, in order to ensure the photosensitive sensitivity of the photosensitive chip, the non-photosensitive area must be treated with light shielding. Therefore, additional light shielding devices are generally used to meet the requirements of the photosensitive chip.

[0003] The traditional packaging form can complete the packaging of the photosensitive chip, but it also faces the following problems. First, high-transmittance plastic packaging materials are still monopolized by foreign material manufacturers, and the material cost is high. Second, the traditional packaging adopts the plastic packaging form of Transfer Mold, and the plastic packaging efficiency is low. Third, the traditional packaging is in the form of single packaging, and the packaging efficiency is low, which is difficult to meet the increasing market demand.

[0004] Therefore, it is urgent to develop a fan-out packaging structure of a lens structure optical sensor chip to reduce the packaging cost and improve the packaging efficiency. SUMMARY

[0005] In view of the above problems, the present application provides a fan-out packaging structure of a lens structure optical sensor chip, which greatly reduces the packaging cost while meeting the performance and packaging structure of the photosensitive chip packaging requirements.

[0006] A fan-out packaging structure of a lens structure optical sensor chip, characterized in that it comprises:

[0007] a chip, which is an optical sensor chip, the upper surface area of the chip being provided with a solder pad and a photosensitive area;

[0008] a plastic packaging layer;

[0009] A black insulating layer has a plurality of concave metal pads on its lower surface, and the lower surface of the metal pads has an exposed tin layer;

[0010] A protective glue layer is made of transparent material;

[0011] A first metal wiring layer;

[0012] A second metal wiring layer;

[0013] The first metal wiring layer is arranged on the pad area of the chip, the chip is arranged on the upper surface of the black insulating layer, and the area of the chip is smaller than the area of the black insulating layer, the plastic encapsulation layer covers the chip and the upper surface of the black insulating layer, the black insulating layer larger than the area of the chip is arranged with metal pads for connection, the upper layer of the black insulating layer and the plastic encapsulation layer of the metal pads for connection is provided with a first window, the upper layer of the plastic encapsulation layer of the pads is provided with a second window, the upper layer of the plastic encapsulation layer of the photosensitive area of the chip is provided with a third window, the second metal wiring layer is arranged on the upper surface of the plastic encapsulation layer and filled into the first window and the second window, the second metal wiring layer connects the pads of the chip and the metal pads for connection in the black insulating layer, the third window is filled with a protective glue layer, the top of the protective glue layer is convex and forms a lens with a specific curvature, and the upper surface of the second metal wiring layer and the plastic encapsulation layer is provided with an insulating protective layer except the area of the protective glue layer.

[0014] It is further characterized in that:

[0015] The second metal wiring layer is provided with an inverted hole on the center of the position corresponding to the first window, the insulating protective layer is filled in the inverted hole, ensuring reliable bonding of the insulating protective layer and the second metal wiring layer and guaranteeing the stability and reliability of the whole structure;

[0016] The insulating protective layer and the protective glue layer are made of different materials, the insulating protective layer is previously covered on the upper surface of the plastic encapsulation layer, then the third window is formed on the photosensitive area of the chip, the protective glue layer is filled in the third window by dispensing and forms a lens with a specific curvature;

[0017] The insulating protective layer and the protective glue layer are made of the same material, which is transparent protective glue material, and are directly formed by a mold;

[0018] The material of the protective glue layer is non-photosensitive or photosensitive polyimide material.

[0019] The application discloses a manufacturing process of a fan-out packaging structure of a lens structure optical sensor chip, and is characterized in that: the method of a board-level fan-out packaging RDL wiring is used to protect the photosensitive area of the chip during the packaging process, and then the method is used to open the packaging after the packaging is basically completed, and then the required lens structure is obtained by using the board-level mold pressing mode.

[0020] Further, the application comprises the following steps:

[0021] S1, preparing a chip, the chip is an optical sensor chip, and the chip is provided with pads and a photosensitive area corresponding to signal interconnection;

[0022] S2, forming a seed layer above the chip, then coating a photoresist layer on the seed layer, and forming corresponding windows by using the photoetching method of exposure and development, wherein the windows correspond to the positions of the pads and the photosensitive area of the chip respectively;

[0023] S3, filling a first metal wiring layer with a certain thickness at the window positions by using the electroplating or electroless plating method, and then removing the residual photoresist and the seed layer in the non-wiring area by using the chemical wet method;

[0024] S4, preparing a temporary carrier, and forming a temporary bonding layer above the temporary carrier;

[0025] S5, forming a plurality of metal pads arranged at intervals on the upper surface of the temporary bonding layer by using the photoetching and electroplating process, and forming a black insulating layer for isolating light by using the vacuum film pressing method;

[0026] S6, mounting the chip obtained in the step S3 on the black insulating layer obtained in the step S5, and the area of the chip is smaller than the area of the black insulating layer;

[0027] S7, the photosensitive area of the chip is oriented, and the chip is plasticized on the surface of the black insulating layer by using the vacuum film pressing or plastic sealing method;

[0028] S8, forming a first window, a second window and a third window on the plastic sealing layer by using the laser drilling or plasma etching method, wherein the first window and the second window are used for signal interconnection, and the third window is used as a window for the photosensitive area, and is prepared for exposing the photosensitive area in the subsequent process;

[0029] S9, forming a second metal wiring layer at the positions of the first window and the second window by using the photoetching and electroplating process;

[0030] When the insulating protective layer and the protective glue layer are made of different materials, the following operation is performed:

[0031] S10, forming a black light-insulating insulating protective layer by using the vacuum mold pressing method, and forming a corresponding window at the photosensitive area;

[0032] S11, the first metal wiring layer covering the photosensitive region is etched and removed by wet etching, exposing the photosensitive region;

[0033] S12, a metal tin layer is formed under the metal solder pad by chemical tin plating, and the metal tin layer is used for welding with the PCB board;

[0034] S13, a layer of transparent protective glue layer is formed on the photosensitive region by printing glue or dispensing glue, forming a lens with a specific curvature.

[0035] It further comprises the following features:

[0036] After step S9, when the insulating protective layer and the protective glue layer are of the same material, both are transparent protective glue material, the following operations are performed:

[0037] T10, the first metal wiring layer covering the photosensitive region is etched and removed by wet etching, exposing the photosensitive region;

[0038] T11, the protective glue layer and the insulating protective layer of the lens structure are formed directly by a mold;

[0039] S12, a metal tin layer is formed under the metal solder pad by chemical tin plating, and the metal tin layer is used for welding with the PCB board.

[0040] After the application, the photosensitive region is protected during the packaging process by using the board-level fan-out packaging RDL wiring method, and then opened after the packaging is basically completed, and then the required lens structure is obtained by using the board-level mold pressing method, which avoids using high-cost transparent plastic packaging materials and greatly reduces the packaging cost. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a cross-sectional view of a specific embodiment of the present application;

[0042] Figure 2 is a cross-sectional view of a specific embodiment of the present application;

[0043] Figure 3 is a schematic diagram of step S1 of the operation process of the present application;

[0044] Figure 4 is a schematic diagram of step S2 of the operation process of the present application;

[0045] Figure 5 is a schematic diagram of step S3 of the operation process of the present application;

[0046] Figure 6 is a schematic diagram of step S4 of the operation process of the present application;

[0047] Figure 7 schematic diagram of step S5 of the operating process of the present application;

[0048] Figure 8 schematic diagram of step S6 of the operating process of the present application;

[0049] Figure 9 schematic diagram of step S7 of the operating process of the present application;

[0050] Figure 10 schematic diagram of step S8 of the operating process of the present application;

[0051] Figure 11 schematic diagram of step S9 of the operating process of the present application;

[0052] Figure 12 schematic diagram of step S10 of the operating process of the present application;

[0053] Figure 13 schematic diagram of step S11 of the operating process of the present application;

[0054] Figure 14 schematic diagram of step S12 of the operating process of the present application;

[0055] Figure 15 schematic diagram of step S13 of the operating process of the present application;

[0056] Figure 16 schematic diagram of step T11 of the operating process of the present application;

[0057] The names corresponding to the serial numbers in the figure are as follows:

[0058] Chip 100, solder pad 110, photosensitive region 120, photoresist 200, fourth window 210, first metal wiring layer 300, temporary carrier plate 400, temporary bonding layer 410, metal solder pad 500, black insulating layer 600, plastic sealing layer 700, first window 710, second window 720, third window 730, second metal wiring layer 800, inverted hole 801, insulating protective layer 900, fifth window 910, metal tin layer 1000, protective glue layer 1100. DETAILED DESCRIPTION

[0059] A fan-out packaging structure of a lens structure optical sensor chip, see Figure 1 and Figure 2 which includes chip 100, plastic sealing layer 700; black insulating layer 600, protective glue layer 1100, first metal wiring layer 300; and second metal wiring layer 800;

[0060] The chip 100 is an optical sensor chip, and the upper surface of the chip 100 is provided with a solder pad 110 and a photosensitive area 120;

[0061] The lower surface of the black insulating layer 600 is provided with a plurality of concave metal solder pads 500, and the lower surface of the metal solder pad 500 is provided with an exposed metal tin layer 1000.

[0062] The protective glue layer 1100 is transparent.

[0063] The chip 100 is arranged on the upper surface of the black insulating layer 600, and the area of the chip 100 is smaller than the area of the black insulating layer 600. The upper surface of the chip 100 and the black insulating layer 600 is covered by a plastic encapsulation layer 700. The black insulating layer 600 arranged at the area larger than the chip 100 is provided with metal solder pads 500 for connection. The upper layer of the black insulating layer 600 and the plastic encapsulation layer 700 of the metal solder pad 500 for connection is provided with a first window 710. The upper layer of the plastic encapsulation layer 700 of the solder pad 110 is provided with a second window 720. The upper layer of the plastic encapsulation layer 700 of the photosensitive area 120 of the chip 100 is provided with a third window 730. A second metal wiring layer 800 is arranged on the upper surface of the plastic encapsulation layer 700 and filled into the first window 710 and the second window 720. The second metal wiring layer 800 connects the solder pad 110 of the chip 100 and the metal solder pad 500 for connection in the black insulating layer 600. The third window 730 is filled with a protective glue layer 1100. The top of the protective glue layer 1100 is convex and forms a lens with a specific curvature. The upper surface of the second metal wiring layer 800 and the plastic encapsulation layer 700 is provided with an insulating protective layer 900 except the area of the protective glue layer.

[0064] In specific implementation, the lens with a specific curvature is realized by optimizing the process of dispensing or printing glue. The height of the arc top of the lens ranges from 5 μm to 1000 μm to meet the photosensitive requirements of different photosensitive chips.

[0065] In specific implementation, the second metal wiring layer 800 is provided with an inverted hole 801 at the center of the position corresponding to the first window 710. The insulating protective layer 900 is filled into the inverted hole 801 to ensure the reliable bonding of the insulating protective layer 900 and the second metal wiring layer 800 and guarantee the stability and reliability of the whole structure.

[0066] In a specific embodiment, see Figure 1 The insulating protective layer 900 and the protective glue layer 1100 are different materials. The insulating protective layer 900 is pre-covered on the upper surface of the plastic encapsulation layer 700. Then, the third window 730 is formed on the photosensitive area 120 of the chip 100. The protective glue layer 1100 is filled into the third window 730 by dispensing and forms a lens with a specific curvature.

[0067] Specific embodiment two, see Figure 2 : the insulating protective layer 900 and the protective adhesive layer 1100 are of the same material, which is a transparent protective adhesive material, and the insulating protective layer 900 and the protective adhesive layer 1100 are directly formed by a mold.

[0068] In a specific embodiment, the material of the protective adhesive layer 1100 is a non-photosensitive or photosensitive polyimide material.

[0069] A manufacturing process of a fan-out packaging structure of a lens structure optical sensor chip is provided, see Figures 1-16 : it uses the method of board-level fan-out packaging RDL wiring to protect the photosensitive area of the chip during packaging, and then opens it after the packaging is basically completed, and then uses the method of board-level molding to obtain the required lens structure.

[0070] It includes the following steps:

[0071] S1, prepare a chip 100, the chip 100 is an optical sensor chip, and the chip 100 has a solder pad 110 and a photosensitive area 120 corresponding to signal interconnection;

[0072] S2, a seed layer is formed above the chip 100 (not shown in the figure, which is a mature structure), and the formation method can be PVD (physical vapor deposition), or CVD (chemical vapor deposition), or chemical copper deposition; then a layer of photoresist 200 is coated on the seed layer, and a fourth opening window 210 is formed by exposure and development of the photoetching method, the fourth opening window 210 corresponds to the positions of the solder pad 110 and the photosensitive area 120 of the chip 100 respectively;

[0073] S3, a first metal wiring layer 300 of a certain thickness is filled in the fourth opening window 210 position by electroplating or chemical plating, and then the residual photoresist and the seed layer in the non-wiring layer area are removed by chemical wet method;

[0074] S4, prepare a temporary carrier 400, and form a temporary bonding layer 410 above the temporary carrier 400; the material of the temporary carrier 400 can be metal, glass, polymer, ceramic and the like; preferably, a stainless steel metal plate is used in the embodiment, and the material of the temporary bonding layer 410 can be, but is not limited to, a high-temperature pyrolytic film, a photolytic temporary bonding adhesive and the like. Preferably, a pyrolytic temporary bonding film is used in the embodiment to match the metal carrier;

[0075] S5, a plurality of spaced metal solder pads 500 are formed on the upper surface of the temporary bonding layer 410 by photoetching and electroplating process, and a black insulating layer 600 for isolating light is formed by vacuum film pressing;

[0076] S6, the chip 100 obtained in step S3 is attached to the black insulating layer 600 obtained in step S5, the area of the chip 100 is smaller than the area of the black insulating layer 600, and the back of the chip 100 is attached with an adhesive film, which is directly attached after the release film is removed;

[0077] S7, the photosensitive area 120 of the chip 100 is oriented, and the chip is encapsulated on the surface of the black insulating layer by vacuum pressing or plastic encapsulation to form a plastic encapsulation layer 700;

[0078] S8, the first window 710, the second window 720 and the third window 730 are formed on the plastic encapsulation layer 700 by laser drilling or plasma etching, the first window 710 and the second window 720 are used for signal interconnection, and the third window 730 is used as a window for the photosensitive area, which is prepared for subsequent exposure of the photosensitive area;

[0079] S9, the second metal wiring layer 800 is formed at the positions of the first window 710 and the second window 720 by photoetching and electroplating process;

[0080] In the structure of the first embodiment, when the insulating protective layer 900 and the protective adhesive layer 1100 are of different materials, the following operations are performed:

[0081] S10, the black opaque insulating protective layer 900 is formed by vacuum pressing, and the corresponding fifth window 910 is formed in the photosensitive area, which can be formed by exposure and development (the corresponding insulating protective layer 900 is a photosensitive material) or laser drilling (the corresponding insulating protective layer 900 is a non-photosensitive material);

[0082] S11, the first metal wiring layer 300 covering the photosensitive area is etched and removed by wet etching to expose the photosensitive area 120;

[0083] S12, a metal tin layer 1000 is formed under the metal solder pad 500 by chemical tin plating, and the metal tin layer 1000 is used for welding with the PCB;

[0084] S13, a layer of transparent protective adhesive layer 1100 is formed on the photosensitive area 120 by printing or dispensing to form a lens with a specific curvature.

[0085] After step S9, in the structure of the second embodiment, when the insulating protective layer 900 and the protective adhesive layer 1100 are of the same material and are both transparent protective adhesive materials, the following operations are performed:

[0086] T10, the first metal wiring layer 300 covering the photosensitive area is etched and removed by wet etching to expose the photosensitive area 120;

[0087] T11, the protective glue layer 1100 and the insulating protective layer of the lens structure are formed directly through a mold;

[0088] S12, a metal tin layer is formed under the metal solder pad by using a chemical tin plating method, and the metal tin layer is used for welding with the outside and the PCB board.

[0089] After the application, the photosensitive area is protected during the packaging process by using the RDL wiring of the board-level fan-out packaging, and then the lens structure is obtained by using the board-level mold, which avoids using the high-cost transparent plastic packaging material and greatly reduces the packaging cost.

[0090] It is apparent for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, but can be implemented in other concrete forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all aspects as illustrative and not restrictive, and the scope of the present application is defined by the appended claims rather than the above description, and it is intended to encompass all changes falling within the meaning and range of equivalents of the claims. Any reference signs in the claims should not be considered as limiting the claims to which they relate.

[0091] In addition, it should be understood that, although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be combined appropriately to form other embodiments that those skilled in the art can understand.

Claims

1. A fan-out packaging structure for a lens-structured optical sensor chip, characterized in that, It includes: The chip is an optical sensor chip, and the upper surface area of ​​the chip is provided with solder pads and a photosensitive area; Molding layer; A black insulating layer with several recessed metal pads on its lower surface, and an exposed tin layer on the lower surface of the metal pads. The protective adhesive layer is made of a transparent material. First metallic wiring layer; and a second metal wiring layer; A first metal wiring layer is provided on the pad area of ​​the chip. The chip is arranged on the upper surface of the black insulating layer, and the area of ​​the chip is smaller than the area of ​​the black insulating layer. The molding compound covers the chip and the upper surface of the black insulating layer. Connecting metal pads are arranged in the area of ​​the black insulating layer larger than the chip. A first window is provided on the black insulating layer and the molding compound on the upper layer of the connecting metal pads. A second window is provided on the molding compound on the upper layer of the pads. A third window is provided on the molding compound on the upper layer of the photosensitive area of ​​the chip. The second metal wiring layer is arranged on the upper surface of the molding compound and fills the first and second windows. The second metal wiring layer connects the pads of the chip and the connecting metal pads in the black insulating layer. The third window is filled with a protective adhesive layer. The top of the protective adhesive layer protrudes outward and forms a lens with a specific curvature. An insulating protective layer is provided on the upper surface of the second metal wiring layer and the molding compound, except for the area of ​​the protective adhesive layer.

2. The fan-out packaging structure of a lens-structured optical sensor chip according to claim 1, characterized in that: The second metal wiring layer has an inverted hole at the center of the upper layer corresponding to the position of the first window, and the insulating protective layer is filled in the inverted hole.

3. The fan-out packaging structure of a lens-structured optical sensor chip according to claim 1, characterized in that: The insulating protective layer and the protective adhesive layer are made of different materials. The insulating protective layer is pre-covered on top of the molding layer, and then a third window is formed in the photosensitive area of ​​the chip. The protective adhesive layer is filled into the third window by dispensing and forms a lens with a specific curvature.

4. The fan-out packaging structure of a lens-structured optical sensor chip according to claim 1, characterized in that: The insulating protective layer and the protective adhesive layer are made of the same material, which is a transparent protective adhesive material. The insulating protective layer and the protective adhesive layer are directly formed by mold.

5. The fan-out packaging structure of a lens-structured optical sensor chip according to claim 1, characterized in that: The protective adhesive layer is made of non-photosensitive or photosensitive polyimide material.

6. A fabrication process for a fan-out packaging structure for fabricating a lens structure optical sensor chip as described in any one of claims 1-5, characterized in that: It utilizes the board-level fan-out package RDL wiring method to protect the chip's photosensitive area during the packaging process, and then opens it after the packaging is basically completed. Then, the required lens structure is obtained by using board-level molding.

7. The fabrication process of the fan-out packaging structure of a lens structure optical sensor chip according to claim 6, characterized in that, It includes the following steps: S1. Prepare the chip. The chip is an optical sensor chip with corresponding signal interconnection pads and photosensitive areas. S2. A seed layer is formed on top of the chip, and then a layer of photoresist is coated on the seed layer. The corresponding windows are formed by photolithography through exposure and development. The windows correspond to the positions of the chip's bonding pads and photosensitive areas, respectively. S3. Fill the window opening with a first metal wiring layer of a certain thickness by electroplating or chemical plating, and then remove the residual photoresist and seed layer in the non-rewiring layer area by chemical wet method. S4. Prepare a temporary carrier board and form a temporary bonding layer on top of the temporary carrier board; S5. Through photolithography and electroplating processes, several spaced metal pads are formed on the upper surface of the temporary bonding layer, and a black insulating layer that blocks light is formed by vacuum pressing. S6. The chip obtained in step S3 is mounted on the black insulating layer obtained in step S5, and the surface area of ​​the chip is smaller than the surface area of ​​the black insulating layer. S7. The photosensitive area of ​​the chip is oriented, and the chip is encapsulated on the surface of the black insulating layer by vacuum lamination or plastic encapsulation. S8. A first window, a second window, and a third window are formed on the molding layer by means of laser drilling or plasma etching. The first and second windows are used for signal interconnection, and the third window is used as a window for the photosensitive area to prepare for the subsequent exposure of the photosensitive area. S9. A second metal wiring layer is formed at the positions of the first and second windows using photolithography and electroplating processes; When the insulating protective layer and the protective adhesive layer are made of different materials, the following operations shall be performed: S10. A black, opaque insulating protective layer is formed by vacuum molding, and a corresponding window is formed in the photosensitive area; S11. The first metal wiring layer covering the photosensitive area is etched away by wet etching to expose the photosensitive area. S12. A tin layer is formed under the metal pads using chemical tin plating. The tin layer is used for soldering to the external components and the PCB board. S13. A transparent protective adhesive layer is formed on the photosensitive area by printing or dispensing adhesive to form a lens with a specific curvature.

8. The fabrication process of the fan-out packaging structure of a lens structure optical sensor chip according to claim 7, characterized in that: After step S9, when the insulating protective layer and the protective adhesive layer are made of the same material, both being transparent protective adhesive, the following operations are performed: T10. The first metal wiring layer covering the photosensitive area is etched away by wet etching to expose the photosensitive area. T11. The protective adhesive layer and insulating protective layer of the lens structure are formed directly through a mold; S12. A tin layer is formed under the metal pads using chemical tin plating. The tin layer is used for soldering to the external PCB board.

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