Packaging structure and packaging method of light-sensitive product capable of preventing light leakage on side surface of chip

Abstract

The invention discloses a packaging structure and a packaging method of a light-sensitive product capable of preventing light leakage on the side surface of a chip, the packaging structure comprises a substrate, the chip, a transparent plastic packaging layer and a shading glue structure, and is characterized in that the chip is fixed on the upper surface of the substrate, the shading glue structure uses black colloid, and the transparent plastic packaging layer is fixed on the upper surface of the substrate. Performing uniform filling and covering along the peripheral area of the chip, keeping the filling and covering height flush with the chip, and not covering the upper surface of the photosensitive area; the invention aims to solve the problems of infrared light leakage and crosstalk in the packaging process of a light-sensitive product. The method is specifically applied to the field of light sensors, and can improve side light leakage of light sensing products, effectively intercept light leakage wave bands and improve anti-interference light capacity, thereby improving accuracy of ambient light sensing and flicker detection.

Description

Technical Field

[0001] This invention relates to the field of light-sensing product technology, specifically to a packaging structure and packaging method for a light-sensing product that prevents light leakage from the side of the chip. Background Technology

[0002] With the continuous development of technology, photosensitive products are increasingly widely used in consumer electronics, smart homes, industrial control, and other fields. Photosensitive products typically include photosensitive elements and signal processing circuits; their core function is to convert light signals into electrical signals, achieving photoelectric conversion. In the design and manufacturing process of photosensitive products, the packaging structure has a significant impact on the product's performance, reliability, and stability.

[0003] In existing optical sensing product packaging technologies, transparent molding compounds are typically used to form the package through a molding process to achieve ambient light sensing and flicker detection functions. However, this traditional process has several significant problems. First, during the packaging process, the wafer is diced into individual chips. Because the photodiode (PD) is too close to the wafer edge, infrared light leakage is prone to occur on the side of the chip, leading to inaccurate Lux values ​​calculated by the photon (PHO) channel. Second, traditional packaging methods are prone to crosstalk. Specifically, the laser emitted during time-of-flight (ToF) operation can be scattered onto the photodiode of the optical sensing chip. This interference light can be mis-collected, thus interfering with the normal operation of the short-pulse flicker detection function, and failing to guarantee the stability and accuracy of the detection function in interference environments. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide a packaging structure and packaging method for a photosensitive product that prevents light leakage from the side of the chip, so as to solve the problems of light leakage and crosstalk on the side of the photosensitive chip, significantly reduce infrared light leakage from the side of the chip, effectively improve the ability to resist interference light, and thus significantly improve the performance and reliability of the product.

[0005] Technical solution: According to one aspect of the present invention, a packaging structure for a light-sensing product with side-leaking protection is provided, comprising a substrate, a chip, a transparent molding layer and a light-shielding adhesive, wherein the chip is fixed to the upper surface of the substrate, and the light-shielding adhesive is uniformly filled and covered around the chip, with the filling and covering height being flush with the chip and not covering the upper surface of the photosensitive area of ​​the chip.

[0006] Furthermore, the chip is fixed to the substrate by an adhesive bonding method.

[0007] Furthermore, the light-shielding adhesive is a black adhesive that can block light of non-target wavelengths.

[0008] Furthermore, the transparent molding layer is disposed on multiple outer peripheral sides of the light-sensitive product.

[0009] According to another aspect of the present invention, a packaging method for a light-sensing product with chip-side light leakage prevention is provided, comprising the following steps: S1. Install and fix chips on the entire substrate, and electrically connect the chips to the pins of the entire substrate to obtain a semi-finished product of the entire photosensitive product. S2. Place the semi-finished product of the whole photosensitive product on the dispensing equipment, and control the dispensing equipment to uniformly fill and cover the area around the chip with black colloid light-blocking glue until the height of the filling and covering is flush with the upper surface of the chip, and ensure that the upper surface of the photosensitive area of ​​the chip is not covered. S3. After applying black glue around the chip, perform a thorough curing process. S4. The photosensitive product processed in step S3 is encapsulated to obtain a finished photosensitive product with black colloid on its outer peripheral side.

[0010] Furthermore, wire bonding technology is used to achieve electrical connection of signals between the chip pads and the pins of the entire substrate.

[0011] Furthermore, in step S2, the amount of adhesive dispensed and the dispensing path need to be controlled during the dispensing process. At the same time, the nozzle is cleaned with the help of a dispensing wiping device during the dispensing process to ensure the stability of the dispensing process and the integrity of the adhesive shape.

[0012] Furthermore, in step S4, the packaging option is plastic encapsulation.

[0013] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: by using black glue as a light-blocking material to prevent light leakage, infrared light leakage and crosstalk are effectively reduced, enabling the photosensitive chip to more accurately capture ambient light and flicker detection signals. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the packaging structure of a light-sensing product with side-leaking protection for the chip, provided by an embodiment of the present invention. Figure 2 This is a schematic flowchart of a packaging method for a light-sensing product that prevents light leakage from the side of a chip, provided as an embodiment of the present invention. Detailed Implementation

[0015] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0016] The existing packaging structures for photosensitive products suffer from the following technical problems: First, during the packaging process, the photodiode (PD) is too close to the edge of the die, causing infrared light leakage from the chip's side. This leads to inaccurate illuminance calculations by the photoelectric channel (PHO) of the ambient light sensor (ALS), severely impacting the measurement accuracy and reliability of the photosensitive product. Second, crosstalk exists, especially when the laser emitted by the time-of-flight (ToF) sensor is working, it can be scattered onto the photodiode of the photosensitive chip. This interference light can be mis-collected by the PHO channel of the photosensitive chip, interfering with the normal operation of flicker detection and compromising the stability and accuracy of flicker detection under interference. Third, traditional solutions such as adjusting the epitaxial layer (EPI) thickness can reduce light leakage, but this simultaneously reduces visible light reception efficiency, affecting the sensitivity of the chip's photodiode, failing to simultaneously resolve the contradiction between light leakage and maintaining sensitivity. Furthermore, the existing light-shielding structures are complex to design and require advanced manufacturing processes, increasing production costs and complexity.

[0017] Example 1 like Figure 1 As shown, this invention provides a packaging structure for a photosensitive product that prevents light leakage from the chip side, in order to solve the problems of light leakage and crosstalk. This invention creatively proposes to use a black colloid that can block light of non-target wavelength bands as a light leakage prevention material. The black colloid is uniformly filled around the chip using a dispensing device, so that the filling height of the black colloid is flush with the upper surface of the chip and does not cover the upper surface of the photosensitive area of ​​the chip. This improves the light leakage from the side of the photosensitive chip and enhances the anti-interference light capability, ensuring the accuracy and reliability of the ambient light sensing and flicker detection functions.

[0018] For example, the photosensitive product provided in the embodiment of the present invention includes a substrate 2, a chip 1, a transparent molding layer 5, and a light-shielding adhesive 4 made of black colloid. The chip 1 is fixed to the upper surface of the substrate 2, and the light-shielding adhesive 4 made of black colloid is uniformly filled and covered around the chip 1. The filling and covering height is flush with the chip 1 and does not cover the upper surface of the photosensitive area 3 of the chip.

[0019] In a preferred embodiment, during the packaging process of the photosensitive product, the chip 1 is fixed to the upper surface of the substrate 2 by adhesive bonding. After the chip 1 is fixed, a light-shielding adhesive 4, made of black colloid, is uniformly filled around the chip 1. The filling height of the light-shielding adhesive 4 is flush with the upper surface of the chip 1. This design can effectively protect the edges of the chip 1 without blocking the photosensitive area 3 of the chip 1, ensuring that light can directly illuminate the photosensitive area 3 of the chip.

[0020] In a preferred embodiment, by fixing the chip 1 to the substrate 2, the bonding method can be a conductive adhesive or silver paste, ensuring a stable mechanical connection and a good electrical connection between the chip 1 and the substrate 2.

[0021] In a preferred embodiment, the light-blocking adhesive 4 is a black colloid that can block light of non-target wavelengths. The black colloid has excellent light-blocking properties, effectively preventing light of non-target wavelengths from interfering with the normal operation of the chip, thus improving the signal quality and accuracy of the photosensitive product. The use of the black colloid can also reduce light scattering and reflection within the packaging structure, reducing the impact of stray light on the photosensitive area of ​​the chip.

[0022] In a preferred embodiment, chip 1 includes a photosensitive region 3, which can be understood as a plurality of photodetectors capable of receiving and converting light signals of specific wavelengths, thereby enhancing the functional versatility and application range of the photosensitive product. The arrangement of photodetectors enables the product to simultaneously detect multiple light signals, improving the product's sensitivity and accuracy.

[0023] In a preferred embodiment, a transparent molding compound 5 is disposed on multiple outer peripheral sides of the photosensitive product. This design forms a complete protective layer, which not only protects the chip and its surrounding circuitry from external environmental damage but also improves the product's mechanical strength and stability. The multi-sided transparent molding compound structure can also evenly distribute the stress generated during the packaging process, reducing the risk of product failure due to uneven stress.

[0024] The technical solution provided by this invention rationally designs the configuration of the transparent molding layer 5 and the light-shielding adhesive 4, effectively solving the problems of light interference and chip protection in traditional packaging structures, and improving the optical performance and reliability of the product. Simultaneously, by using a black colloid as the light-shielding adhesive, this photosensitive product effectively blocks non-target wavelength light, improving the detection accuracy and reliability of the photosensitive product.

[0025] Example 2 The technical solution provided by this invention can effectively solve the problem of light leakage from the side of the chip, prevent crosstalk interference, and maintain the high sensitivity of the chip, thereby improving the measurement accuracy and reliability of optical sensing products. Figure 2 As shown, this embodiment of the invention also provides a packaging method for a light-sensing product that prevents light leakage from the chip side, comprising the following steps: S1. Install and fix chip 1 on the whole substrate, and electrically connect chip 1 to the pins of the whole substrate 2 to obtain a semi-finished product of the whole photosensitive product.

[0026] In this step, wire bonding is used to establish electrical connections between the chip pads and the pins of the entire substrate. Wire bonding is a commonly used chip connection method that connects the pads on the chip to the pins on the substrate using fine metal wires, forming an electrical path. This connection method is characterized by high reliability and mature technology, ensuring the stability of signal transmission between the chip and the substrate.

[0027] S2. Place the semi-finished product of the whole photosensitive product on the dispensing equipment, and control the dispensing equipment to uniformly fill and cover the surrounding area of ​​the chip 1 with black colloid light-blocking adhesive 4 until the height of the filling and covering is flush with the upper surface of the chip 1, and ensure that the upper surface of the photosensitive area of ​​the chip 1 is not covered.

[0028] During the dispensing process, it is necessary to control the dispensing volume and dispensing path. Simultaneously, a dispensing wiping device is used to clean the nozzles during dispensing to ensure stable dispensing and complete adhesive coverage. The dispensing path generally follows a circular pattern around the chip, starting from one corner and dispensing in a clockwise or counter-clockwise direction. The dispensing volume is controlled by adjusting the pressure and time parameters of the dispensing equipment to ensure the adhesive fill height is flush with the chip's surface. The dispensing wiping device is usually located on one side of the dispensing equipment. After each dispensing cycle, the nozzle automatically moves to the wiping device for cleaning, preventing adhesive buildup or drying at the nozzle and affecting subsequent dispensing quality.

[0029] S3. After applying black glue around the chip, perform a thorough curing process.

[0030] Curing processes typically employ either thermal curing or ultraviolet (UV) curing. Thermal curing involves placing the dispensed product in an oven and maintaining it at a specific temperature for a set time to allow the black, light-shielding adhesive to fully cure. UV curing, on the other hand, uses UV light of a specific wavelength to irradiate the adhesive, promoting rapid curing. Once cured, the black adhesive forms a light-shielding structure that effectively blocks external light from interfering with the chip, improving the signal accuracy and stability of the photosensitive product.

[0031] S4. The photosensitive product processed in step S3 is packaged to obtain a finished product with multiple photosensitive products having a light-shielding adhesive structure on the outer peripheral side.

[0032] In this step, molding encapsulation is selected. Molding encapsulation involves placing the cured photosensitive product into a mold, injecting molding materials such as epoxy resin, and then heating and pressurizing the molding material to cure it, forming a protective layer for the chip. The molding material protects the chip from external environmental influences such as moisture and dust, while also improving the product's mechanical strength and stability. After molding, the entire photosensitive product is cut into multiple individual finished photosensitive products.

[0033] The packaging method provided in this invention results in a photosensitive product with a black light-shielding adhesive structure on its outer peripheral side. This effectively prevents stray light from entering the photosensitive area of ​​the chip from the side, improving the signal quality and detection accuracy of the photosensitive product. Simultaneously, because the light-shielding adhesive structure is flush with the chip's upper surface and does not cover the photosensitive area, the normal photosensitive function of the photosensitive product is guaranteed. The entire packaging process is simple, highly efficient, and suitable for mass production.

Claims

1. A packaging structure for a light-sensing product with side-leaking protection, comprising a substrate, a chip, a transparent molding layer, and a light-shielding adhesive, characterized in that, The chip is fixed to the upper surface of the substrate, and the light-shielding adhesive is uniformly filled and covered around the chip, with the filling height being flush with the chip and not covering the upper surface of the chip's photosensitive area.

2. The packaging structure according to claim 1, characterized in that, The chip is fixed to the substrate by an adhesive bonding method.

3. The packaging structure according to claim 1, characterized in that, The light-shielding adhesive is a black colloid that can block light of non-target wavelengths.

4. The packaging structure according to claim 1, characterized in that, The transparent molding layer is disposed on multiple outer peripheral sides of the light-sensitive product.

5. A packaging method for a light-sensing product with side-leaking protection for the chip, characterized in that, Includes the following steps: S1. Install and fix chips on the entire substrate, and electrically connect the chips to the pins of the entire substrate to obtain a semi-finished product of the entire photosensitive product. S2. Place the semi-finished product of the whole photosensitive product on the dispensing equipment, and control the dispensing equipment to uniformly fill and cover the area around the chip with black glue-based light-shielding adhesive until the height of the filling and covering is flush with the upper surface of the chip, and ensure that the upper surface of the photosensitive area of ​​the chip is not covered. S3. After applying black glue around the chip, perform a thorough curing process. S4. The photosensitive product processed in step S3 is packaged to obtain a finished photosensitive product with a black colloid light-blocking adhesive structure on its outer peripheral side.

6. The packaging method according to claim 5, characterized in that, The electrical connection between the chip pads and the pins of the entire substrate is achieved using wire bonding technology.

7. The packaging method according to claim 5, characterized in that, In step S2, during the dispensing process, it is necessary to control the amount of glue dispensed and the dispensing path. At the same time, the nozzle should be cleaned with a dispensing wiping device during the dispensing process to ensure the stability of the dispensing process and the integrity of the glue shape.

8. The packaging method according to claim 5, characterized in that, Step S4 describes selecting plastic encapsulation.

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