Optical sensor and packaging method thereof
By using transparent DAF film and hydrosol in the packaging method of optical sensors, combined with laser groove and removal of plastic sealing materials, the existing optical sensor packaging process is solved, and efficient and reliable window packaging is achieved.
Patent Information
- Application Number
- CN202411903075.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-23
- Publication Date
- 2025-03-21
AI Technical Summary
The existing optical sensor packaging process is inefficient, and due to the limitations of the lithography process, coating glass cannot be used, resulting in limited optical performance, and high substrate flatness requirements and complex process.
A new packaging method is adopted, which includes attaching a transparent DAF film to the surface of the glass monomer and attaching it to the photosensitive area of the chip, and then screen-printing the hydrosol on the surface of the glass monomer, performing semi-encapsulation and plastic sealing, and finally completing the window packaging by laser groove and removing the hydrosol and plastic sealing material.
This method does not require a photolithography cofferdam, and can use coated glass to improve the performance of the optical sensor, avoid water vapor entering, ensure reliability, and reduce the requirements for substrate flatness, simplify the process flow, and improve efficiency.
Smart Images
Figure CN119677245A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of semiconductor process technology, and in particular to an optical sensor and a packaging method thereof. Background Art
[0002] Optical sensors are sensors that measure based on optical principles. They are widely used because of their non-contact and non-destructive measurement, almost no interference, high-speed transmission, and telemetry and remote control. In order to achieve optical measurement, it is necessary to ensure that the photosensitive area on the surface of the optical sensor can receive light after packaging, so the optical sensor needs to be packaged with windows.
[0003] The existing optical sensor packaging process generally involves first making a dam on the glass through photolithography, screen-printing glue on top of the dam and then bonding the wafer; then bonding the glass to the photosensitive area of a single chip (Die) through glue; and finally using a special mold for plastic sealing.
[0004] However, in the existing optical sensor packaging process, since the photolithography process requires multiple exposures and developments, if coated glass is used, the developer and glue in the photolithography can easily cause the film layer to delaminate or even fall off, causing water vapor to enter and affect the reliability of the optical sensor. Therefore, the current packaging process can only perform cofferdam processing on ordinary white glass. At the same time, when the size of the glass on a single chip is too large, it is easy for residual photoresist to affect the performance of the optical sensor. In addition, the existing packaging process requires the development of a special mold to ensure the smooth edges during plastic sealing, and has extremely high requirements for the flatness of the substrate. If the thickness of the substrate is uneven, the process needs to be frequently adjusted during plastic sealing. Not only is the process cumbersome and time-consuming, it is also very easy to cause glue overflow, resulting in poor plastic sealing. Summary of the invention
[0005] An object of the present invention is to provide an optical sensor and a packaging method thereof, so as to at least solve the problem of low efficiency of the existing optical sensor packaging method.
[0006] In order to solve the above technical problems, the present invention provides a packaging method of an optical sensor, comprising: providing a substrate; Fixing the chip on the substrate; A transparent DAF film is attached to the clean surface of the glass monomer; Place the transparent DAF film toward the photosensitive area of the chip and attach the glass monomer to the chip surface; Screen printing a hydrosol on the surface of a glass monomer; Wire bonding a chip pad of the chip to a substrate pad of the substrate to obtain a semi-packaged device; Plastic-sealing the semi-encapsulated device to obtain a plastic-encapsulated device; Slot the plastic-encapsulated device until the hydrosol is exposed; The hydrosol and the plastic sealing material on the surface of the glass monomer in the grooved plastic sealing part are removed to complete the window packaging.
[0007] Optionally, in the packaging method of the optical sensor, the method of fixing the chip on the substrate includes: Slicing the wafer into individual chips; Attach the chip to the substrate using die-bonding glue; Bake and cure the die-bonding glue to fix the chip on the substrate.
[0008] Optionally, in the packaging method of the optical sensor, the thickness of the die-bonding glue is 3.5-5.5 μm.
[0009] Optionally, in the packaging method of the optical sensor, the method of attaching a transparent DAF film to the surface of a clean glass monomer includes: Cleaning glass; Attach a transparent DAF film to the glass surface; The glass with the transparent DAF film attached is divided into glass monomers according to the chip size.
[0010] Optionally, in the packaging method of the optical sensor, the method of dividing the glass with the transparent DAF film attached into glass monomers according to the chip size includes: Calculate the size of the glass monomer according to the chip size; The glass with the transparent DAF film attached thereto is divided according to the calculated size of the glass monomer; Among them, the size of the glass monomer meets: 50~70μm larger than the photosensitive area of the chip; Furthermore, after the glass monomer is attached to the chip surface, the distance between the edge of the glass monomer and the edge of the chip pad is 154-250 μm.
[0011] Optionally, in the packaging method of the optical sensor, the method of attaching the glass monomer to the chip surface includes: Using a chip mounter, the glass monomer is attached to the chip surface; Through pressure baking, bubbles between the glass monomer and the photosensitive area of the chip are eliminated and solidified.
[0012] Optionally, in the packaging method of the optical sensor, the method of screen printing the hydrosol on the surface of the glass monomer includes: The hydrosol is screen-printed on the surface of the glass monomer corresponding to the photosensitive area of the chip, and the thickness of the hydrosol does not exceed 300 μm.
[0013] Optionally, in the packaging method of the optical sensor, the method of slotting the plastic package component includes: Use an infrared laser cutting machine with a galvanometer to laser groove plastic-encapsulated components.
[0014] Optionally, in the packaging method of the optical sensor, the method of removing the hydrosol and the plastic sealing material on the surface of the glass monomer in the grooved plastic sealing part comprises: The slotted plastic-sealed part is placed in a solvent to remove the hydrosol and plastic-sealing material on the surface of the glass monomer; Clean the surface of the glass monomer.
[0015] Optionally, in the packaging method of the optical sensor, when a plurality of chips are fixed on the same substrate, the packaging method further comprises: The substrate is cut according to the positions of the multiple chips to obtain a single window-packaged optical sensor.
[0016] In order to solve the above technical problems, the present invention also provides an optical sensor, which is packaged using the packaging method of an optical sensor as described in any of the above items, and the optical sensor includes a substrate, a chip, a transparent DAF film and a glass monomer arranged in sequence from bottom to top, and a plastic package covering the surface of the chip and exposing the surface of the glass monomer; the top of the chip has a photosensitive area; the transparent DAF film and the glass monomer cover the photosensitive area.
[0017] Optionally, in the optical sensor, the chip has a chip pad, the substrate has a substrate pad, and the chip pad and the substrate pad are wire-bonded.
[0018] Optionally, in the optical sensor, the size of the glass monomer is 50-70 μm larger than the size of the photosensitive area, and the distance between the edge of the glass monomer and the edge of the chip pad is 154-250 μm.
[0019] The optical sensor and packaging method thereof provided by the present invention include: providing a substrate; fixing a chip on the substrate; attaching a transparent DAF film to the surface of a clean glass monomer; placing the transparent DAF film toward a photosensitive area of the chip and attaching the glass monomer to the surface of the chip; screen-printing a hydrosol on the surface of the glass monomer; wire-bonding a chip pad of the chip to a substrate pad of the substrate to obtain a semi-packaged device; plastic-sealing the semi-packaged device to obtain a plastic-sealed device; slotting the plastic-sealed device until the hydrosol is exposed; and removing the hydrosol and the plastic sealing material on the surface of the glass monomer in the slotted plastic-sealed part to complete the window packaging. Since the entire process does not require photolithography cofferdams, not only can coated glass be used to improve the optical performance of the optical sensor, but it can also avoid the entry of water vapor caused by delamination or shedding of the film layer, thereby ensuring the reliability of the optical sensor; by coating the glass surface with hydrosol, the hydrosol can be completely removed when the plastic sealing material on the glass surface is removed, and no glue residue is left; and the packaging method provided by the present invention does not have high requirements on the flatness of the substrate during plastic sealing, thereby reducing the process difficulty and solving the problem of low efficiency of existing optical sensor packaging methods. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 A flow chart of a packaging method for an optical sensor provided in this embodiment; 2(A) to 2(I) are schematic cross-sectional views of the structure of the optical sensor corresponding to each step in the optical sensor packaging method provided in this embodiment; Figure 3 A schematic diagram of the size requirements of the optical sensor provided in this embodiment; The descriptions of the reference numerals are as follows: 100-substrate; 110-substrate pad; 200-chip; 210-photosensitive area; 220-chip pad; 300-glass monomer; 310-DAF film; 400-hydrosol; 500-lead; 600-plastic package; 610-groove. DETAILED DESCRIPTION
[0021] The optical sensor and the packaging method thereof proposed in the present invention are further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In addition, the structure shown in the accompanying drawings is often a part of the actual structure. In particular, the emphasis that each drawing needs to show is different, and sometimes different proportions are used.
[0022] It should be noted that the terms "first", "second", etc. in the specification, claims and drawings of the present invention are used to distinguish similar objects in order to describe the embodiments of the present invention, rather than to describe a specific order or sequence. It should be understood that the structures used in this way can be interchanged under appropriate circumstances. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.
[0023] This embodiment provides a packaging method for an optical sensor, such as Figure 1 As shown, including: S1, providing a substrate; S2, fixing the chip on the substrate; S3, attaching a transparent DAF film on the clean surface of the glass monomer; S4, placing the transparent DAF film toward the photosensitive area of the chip and attaching the glass monomer to the chip surface; S5, screen printing hydrosol on the surface of glass monomer; S6, wire bonding the chip pad of the chip to the substrate pad of the substrate to obtain a semi-packaged device; S7, plastic-sealing the semi-packaged device to obtain a plastic-packaged device; S8, slotting the plastic-encapsulated device until the hydrosol is exposed; S9, removing the hydrosol and the plastic sealing material on the surface of the glass monomer in the grooved plastic sealing part to complete the window packaging.
[0024] The packaging method for the optical sensor provided in the present embodiment does not require a photolithography cofferdam during the entire process, so that not only can the optical performance of the optical sensor be improved by using coated glass, but also the entry of water vapor caused by delamination or shedding of the film layer can be avoided, thereby ensuring the reliability of the optical sensor; by coating the glass surface with hydrosol, the hydrosol can be completely removed when the plastic sealing material on the glass surface is removed, and no glue residue is left; and the packaging method provided by the present invention does not have high requirements on the flatness of the substrate during plastic sealing, thereby reducing the process difficulty and solving the problem of low efficiency of the existing optical sensor packaging method.
[0025] It should be noted that, in actual application, step S3 can be performed before step S1 or step S2, or can be performed simultaneously with step S1 or step S2, that is, the implementation of step S3 is independent of step S1 and step S2. The replacement of the order of steps without violating the main purpose of this application should also fall within the scope of protection of this application.
[0026] Specifically, in this embodiment, in step S1 , as shown in FIG. 2 (A) , a substrate 100 is provided, wherein the substrate 100 further has a substrate pad 110 .
[0027] This embodiment has no strict requirement on the flatness of the substrate 100 , as long as the chip can be reliably fixed to the substrate 100 and the subsequent substrate pad 110 and the chip pad can be wire-bonded.
[0028] Furthermore, in this embodiment, step S2, the method of fixing the chip on the substrate includes: S21, dividing the wafer into individual chips.
[0029] Specifically, in this embodiment, the wafer can be cut into individual chips (Die) by a cutter wheel cutter. The method of cutting by a cutter wheel cutter is well known to those skilled in the art, and will not be described in detail in this application.
[0030] S22, attaching the chip to the substrate by using a die-bonding glue.
[0031] Specifically, in this embodiment, the die-bonding glue may be applied to the bottom of the chip (the side opposite to the photosensitive area of the chip), and then the bottom of the chip coated with the die-bonding glue may be placed on the substrate 100 .
[0032] In order to ensure that the die-bonding glue can reliably fix the chip on the substrate 100 while minimizing the time for glue overflow and baking and curing, and to ensure that the chip is placed as horizontally as possible relative to the substrate 100, in this embodiment, the thickness of the die-bonding glue is controlled to be 3.5~5.5μm.
[0033] S23, baking and curing the die-bonding glue to fix the chip on the substrate.
[0034] In practical applications, the temperature and time of baking and curing need to be reasonably selected according to the material and thickness of the bonding glue. The structure of the semi-finished product after baking and curing is shown in FIG2 (B) (the bonding glue is located between the chip 200 and the substrate 100, which is not shown in the figure).
[0035] As shown in FIG2(B) , the top of the chip 200 has a photosensitive region 210 and a chip pad 220 . The photosensitive region 210 is used to receive light, and the chip pad 220 is used to wire bond with the substrate pad 110 to achieve electrical connection between the chip 200 and the substrate 100 .
[0036] Furthermore, in this embodiment, step S3, the method of attaching a transparent DAF film on the surface of a clean glass monomer includes: S31, cleaning glass.
[0037] By cleaning the glass, the glass surface is ensured to be free of dirt, thereby ensuring that the subsequent process is free of dirt and contamination.
[0038] In practical applications, the glass can be ordinary white glass or coated glass. When coated glass is selected, the optical advantages of coated glass can be utilized to effectively improve the sensitivity and accuracy of the optical sensor.
[0039] S32, attaching a transparent DAF film to the glass surface.
[0040] DAF film (Die Attach Film) is a material designed specifically for chip attachment. Its core advantage lies in its strong cutting protection ability and excellent expansion preservation characteristics, which can ensure that the chip remains intact during the laser cutting process and will not be scattered due to vibration or impact. In addition, DAF film can maintain structural integrity under heavy load conditions and is suitable for processing large-size and heavy-weight chips. DAF film can achieve high-reliability, high-performance, high-speed and high-device density packaging, becoming one of the key technologies.
[0041] By attaching a transparent DAF film to the glass, this embodiment can not only ensure the effective bonding between the glass and the chip in the subsequent process and the reliability of the optical sensor device structure, but also ensure that the photosensitive area of the chip can receive sufficient light through the glass and the transparent DAF film, and can also ensure the integrity and cutting accuracy of the glass when dividing the glass into glass monomers.
[0042] S33, dividing the glass with the transparent DAF film attached thereto into glass monomers according to the chip size.
[0043] Specifically, in this embodiment, the glass can be cut into individual glass monomers by a cutter wheel cutter. The method of cutting by a cutter wheel cutter is well known to those skilled in the art and will not be described in detail in this application. The structure of the glass monomer 300 with the transparent DAF film 310 attached is shown in FIG2 (C).
[0044] In order to ensure that the glass monomer 300 can completely cover the photosensitive area 210 of the chip, and at the same time, in order to avoid structural interference between the glass monomer 300 and the chip pad 220 of the chip and affect the wire bonding of the chip pad 220, in practical applications, it is necessary to cut the glass according to the size of the chip to obtain a glass monomer 300 of appropriate size. Specifically, the size of the glass monomer 300 can be calculated according to the chip size; then, the glass attached with the transparent DAF film 310 can be divided according to the calculated size of the glass monomer 300. Among them, the size of the glass monomer 300 must meet the following requirements: 50~70μm larger than the size of the photosensitive area 210 of the chip; and after the glass monomer 300 is attached to the surface of the chip 200, the distance between the edge of the glass monomer 300 and the edge of the chip pad 220 is 154~250μm.
[0045] It should be noted that the dimensions described in this embodiment should be understood as length and width. In practical applications, the dimensions of the glass monomer 300 need to be determined by comprehensively considering factors such as the spacing between the photosensitive region 210 and the chip pad 220 on the chip, the dimensions of the photosensitive region 210, the cutting accuracy of the cutting machine, and the glass pasting accuracy of the chip mounter.
[0046] Furthermore, in this embodiment, step S4, the method of placing the transparent DAF film toward the photosensitive area of the chip and attaching the glass monomer to the surface of the chip includes: S41, using a chip mounter to attach the glass monomer to the chip surface.
[0047] Specifically, in this embodiment, the transparent DAF film 310 is directed toward the photosensitive region 210 of the chip, and the glass monomer 300 is attached to the surface of the chip 200 so that the glass monomer 300 covers the photosensitive region 210 of the chip.
[0048] At this time, the transparent DAF film 310 is not completely in contact with and fixed to the surface of the chip 200 . Therefore, in order to fix the transparent DAF film 310 on the chip 200 and completely fit the photosensitive area 210 , pressure baking is required.
[0049] S42 , through pressure baking, the bubbles between the glass monomer 300 and the photosensitive area 210 of the chip are eliminated and solidified.
[0050] The semi-finished product structure after this step is shown in FIG2(D).
[0051] In practical applications, the pressure, time and temperature of pressure baking need to be determined comprehensively based on factors such as the material of the glass monomer 300, the material of the transparent DAF film 310, the size of the chip 200, etc., to ensure that after pressure baking, there are no bubbles between the glass monomer 300 and the photosensitive area 210 of the chip, and at the same time, the structures of the glass monomer 300 and the chip 200 are intact and undamaged, the substrate 100 has no obvious deformation, and the connection between the chip 200 and the substrate 100 is firm.
[0052] Furthermore, in this embodiment, in step S5, the hydrosol is screen-printed on the surface of the glass monomer.
[0053] Specifically, in practical applications, it is necessary to screen-print the hydrosol at least on the surface of the glass monomer 300 corresponding to the photosensitive area 210 of the chip to ensure that the subsequent window opening can expose the entire photosensitive area 210 .
[0054] A hydrosol is a sol using water as a dispersion medium, wherein the dispersed particles can be single macromolecules or aggregates of many molecules. A hydrosol is easy to dissolve, so the use of a hydrosol in this embodiment can improve the efficiency of subsequent window opening and reduce process complexity.
[0055] In order to improve the efficiency of subsequent removal of the hydrosol and save process costs, in this embodiment, the thickness of the hydrosol does not exceed 300 μm.
[0056] The semi-finished product structure after completing this step is shown in FIG2 (E). In the process shown in FIG2 (E), the vertical projection of the hydrosol 400 covers the entire photosensitive area 210 and covers part of the glass monomer 300. In this way, the hydrosol 400 can be prevented from leaking on the side of the glass monomer 300, ensuring the sealing of the optical sensor after packaging.
[0057] Of course, in other embodiments, the vertical projection of the hydrosol 400 may completely cover the glass monomer 300 , that is, the hydrosol 400 is screen-printed on the entire surface of the glass monomer 300 to reduce the process accuracy requirement of screen printing.
[0058] Furthermore, in this embodiment, in step S6, as shown in FIG2(F), the chip pad 220 of the chip is wire-bonded with the substrate pad 110 of the substrate to obtain a semi-packaged device. The specific implementation of wire bonding is well known to those skilled in the art, and will not be described in detail in this application.
[0059] Furthermore, in this embodiment, in step S7, the semi-encapsulated device is plastic-encapsulated to obtain a plastic-encapsulated device.
[0060] As shown in FIG. 2 (G), the plastic package 600 completely covers the substrate pad 110, the chip 200, the chip pad 220, the glass monomer 300, the hydrosol 400 and the lead 500 on the surface of the substrate 100, thereby plastic-sealing the entire device.
[0061] The specific implementation of the plastic encapsulation is also well known to those skilled in the art, and this application will not be repeated. In some specific embodiments, part of the substrate pads 110 on the surface of the substrate 100 may also be exposed according to actual needs to facilitate the subsequent electrical connection of the exposed substrate pads 110 with other devices.
[0062] Furthermore, in this embodiment, in step S8, grooves are cut in the plastic package component until the hydrosol is exposed.
[0063] Specifically, in this embodiment, an infrared laser cutting machine with a galvanometer is used to laser groove the plastic package component, thereby achieving efficient groove cutting while ensuring that the glass monomer 300 is not damaged. The structure of the plastic package component after groove cutting is shown in FIG2 (H).
[0064] In practical applications, the position of the groove 600 corresponds to the hydrosol 400. In order to increase the efficiency of subsequent window opening, when the size of the photosensitive area 210 is large, multiple grooves 600 can be opened on the hydrosol 400, or the width of the groove 600 can be widened.
[0065] Finally, in this embodiment, step S9 is to remove the hydrosol 400 and the molding compound 600 on the surface of the glass monomer 300 in the grooved plastic package to complete the window packaging, which includes: S91 , placing the grooved plastic package into a solvent to remove the hydrosol 400 and the plastic package material 600 on the surface of the glass monomer 300 .
[0066] Specifically, the solvent should be a solvent that can dissolve the hydrosol 400, so that the hydrosol 400 can be completely removed. When removing the hydrosol 400, the plastic encapsulation material 600 on the surface of the hydrosol 400 is also removed together, while the plastic encapsulation material 600 in other parts is retained, thereby completing the window opening.
[0067] S92, cleaning the surface of the glass monomer 300.
[0068] To ensure the photosensitivity of the photosensitive area 210, the surface of the glass monomer 300 needs to be cleaned. The cleaning method is not limited to water cleaning, plasma cleaning, etc., so as to completely remove the residual hydrosol 400 or impurities such as dust on the surface of the glass monomer 300.
[0069] The structure of the packaged optical sensor obtained after the window is opened is shown in FIG2 (I). As can be seen from FIG2 (I), a window is opened on the photosensitive area 210 of the chip, and the glass monomer 300 is used to provide protection for the photosensitive area 210, so that the photosensitive area 210 is completely exposed, so that the photosensitive area 210 can effectively receive light, and at the same time, the entire chip structure is packaged by the plastic package 600 and the glass monomer 300.
[0070] The above embodiment only takes a single chip as an example to illustrate the packaging method of the optical sensor provided by the present application. In practical applications, in order to improve manufacturing efficiency, multiple chips 200 can be fixed on the same substrate 100. In this case, the window packaging of multiple chips 200 can be achieved according to the above steps. Afterwards, the substrate 100 can be cut using a cutter wheel cutter according to the positions of the multiple chips 200 to obtain a single window packaged optical sensor.
[0071] Corresponding to the packaging method provided in this embodiment, this embodiment also provides an optical sensor, which is packaged using the packaging method of the optical sensor as described above, as shown in FIG2 (I), wherein the optical sensor includes a substrate 100, a chip 200, a transparent DAF film 310 and a glass monomer 300 arranged in sequence from bottom to top, and a plastic package 600 covering the surface of the chip 200 and exposing the surface of the glass monomer 300; the top of the chip 200 has a photosensitive area 210; the transparent DAF film 310 and the glass monomer 300 cover the photosensitive area 210.
[0072] Furthermore, in this embodiment, the chip 200 has a chip pad 220 , the substrate 100 has a substrate pad 110 , and the chip pad 220 and the substrate pad 110 are wire-bonded.
[0073] According to the above packaging method, in this embodiment, the size of the glass monomer 300 in the optical sensor is 50-70 μm larger than the size of the photosensitive area 210, and the distance between the edge of the glass monomer 300 and the edge of the chip pad 220 is 154-250 μm, that is, Figure 3 As shown, a is 50~70μm, and b is 154~250μm.
[0074] In this way, taking into account the deviation of the patch process, it can be ensured that the glass monomer 300 completely covers the photosensitive area 210 while avoiding structural interference between the glass monomer 300 and the chip pad 220, ensuring that the transparent DAF film 310 and the glass monomer 300 will not press the chip pad 220 and the wire during wire bonding.
[0075] The optical sensor and packaging method provided by the present invention do not require photolithography cofferdams in the entire process, so not only can coated glass be used to improve the optical performance of the optical sensor, but also the entry of water vapor caused by delamination or shedding of the film layer can be avoided, thereby ensuring the reliability of the optical sensor; by coating the glass surface with hydrosol, the hydrosol can be completely removed when the plastic sealing material on the glass surface is removed, and no glue residue is left; and the packaging method provided by the present invention does not have high requirements on the flatness of the substrate during plastic sealing, thereby reducing the process difficulty and solving the problem of low efficiency of the existing optical sensor packaging method.
[0076] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other. In addition, the different parts between the various embodiments can also be used in combination with each other, and the present invention is not limited to this.
[0077] The optical sensor and packaging method thereof provided by the present invention include: providing a substrate; fixing a chip on the substrate; attaching a transparent DAF film to the surface of a clean glass monomer; placing the transparent DAF film toward a photosensitive area of the chip and attaching the glass monomer to the surface of the chip; screen-printing a hydrosol on the surface of the glass monomer; wire-bonding a chip pad of the chip to a substrate pad of the substrate to obtain a semi-packaged device; plastic-sealing the semi-packaged device to obtain a plastic-sealed device; slotting the plastic-sealed device until the hydrosol is exposed; and removing the hydrosol and the plastic sealing material on the surface of the glass monomer in the slotted plastic-sealed part to complete the window packaging. Since the entire process does not require photolithography cofferdams, not only can coated glass be used to improve the optical performance of the optical sensor, but it can also avoid the entry of water vapor caused by delamination or shedding of the film layer, thereby ensuring the reliability of the optical sensor; by coating the glass surface with hydrosol, the hydrosol can be completely removed when the plastic sealing material on the glass surface is removed, and no glue residue is left; and the packaging method provided by the present invention does not have high requirements on the flatness of the substrate during plastic sealing, thereby reducing the process difficulty and solving the problem of low efficiency of existing optical sensor packaging methods.
[0078] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.
Claims
1. A packaging method for an optical sensor, characterized in that: include: providing a substrate; Fixing the chip on the substrate; A transparent DAF film is attached to the clean surface of the glass monomer; Place the transparent DAF film toward the photosensitive area of the chip and attach the glass monomer to the chip surface; Screen printing a hydrosol on the surface of a glass monomer; Wire bonding a chip pad of the chip to a substrate pad of the substrate to obtain a semi-packaged device; Plastic-sealing the semi-encapsulated device to obtain a plastic-encapsulated device; Slot the plastic-encapsulated device until the hydrosol is exposed; The hydrosol and the plastic sealing material on the surface of the glass monomer in the grooved plastic sealing part are removed to complete the window packaging.
2. The packaging method of the optical sensor according to claim 1, characterized in that: The method for fixing the chip on the substrate comprises: Slicing the wafer into individual chips; Attach the chip to the substrate using die-bonding glue; Bake and cure the die-bonding glue to fix the chip on the substrate.
3. The packaging method of the optical sensor according to claim 2, characterized in that: The thickness of the solid crystal glue is 3.5-5.5 μm.
4. The packaging method of an optical sensor according to claim 1, characterized in that: The method for attaching a transparent DAF film to the surface of a clean glass monomer comprises: Cleaning glass; Attach a transparent DAF film to the glass surface; The glass with the transparent DAF film attached is divided into glass monomers according to the chip size.
5. The packaging method of the optical sensor according to claim 4, characterized in that: The method of dividing the glass with the transparent DAF film attached into glass monomers according to the chip size includes: Calculate the size of the glass monomer according to the chip size; The glass with the transparent DAF film attached thereto is divided according to the calculated size of the glass monomer; Among them, the size of the glass monomer meets: 50~70μm larger than the photosensitive area of the chip; Furthermore, after the glass monomer is attached to the chip surface, the distance between the edge of the glass monomer and the edge of the chip pad is 154-250 μm.
6. The packaging method of an optical sensor according to claim 1, characterized in that: The method of attaching the glass monomer to the chip surface comprises: Using a chip mounter, the glass monomer is attached to the chip surface; Through pressure baking, bubbles between the glass monomer and the photosensitive area of the chip are eliminated and solidified.
7. The packaging method of an optical sensor according to claim 1, characterized in that: The method for screen printing a hydrosol on the surface of a glass monomer comprises: The hydrosol is screen-printed on the surface of the glass monomer corresponding to the photosensitive area of the chip, and the thickness of the hydrosol does not exceed 300 μm.
8. The optical sensor packaging method according to claim 1, characterized in that: The method for grooving a plastic packaged device comprises: Use an infrared laser cutting machine with a galvanometer to laser groove plastic-encapsulated components.
9. The optical sensor packaging method according to claim 1, characterized in that: The method for removing the hydrosol and the plastic sealing material on the surface of the glass monomer in the grooved plastic sealing part comprises: The slotted plastic-sealed part is placed in a solvent to remove the hydrosol and plastic-sealing material on the surface of the glass monomer; Clean the surface of the glass monomer.
10. The optical sensor packaging method according to claim 1, characterized in that: When a plurality of chips are fixed on the same substrate, the packaging method further comprises: The substrate is cut according to the positions of the multiple chips to obtain a single window-packaged optical sensor.
11. An optical sensor encapsulated by the optical sensor encapsulation method according to any one of claims 1 to 10, characterized in that: The optical sensor comprises a substrate, a chip, a transparent DAF film and a glass monomer which are arranged in sequence from bottom to top, and a plastic package which covers the surface of the chip and exposes the surface of the glass monomer; the top of the chip has a photosensitive area; the transparent DAF film and the glass monomer cover the photosensitive area.
12. The optical sensor according to claim 11, characterized in that The chip has a chip pad, the substrate has a substrate pad, and the chip pad and the substrate pad are wire-bonded.
13. The optical sensor according to claim 12, characterized in that The size of the glass monomer is 50-70 μm larger than the size of the photosensitive area, and the distance between the edge of the glass monomer and the edge of the chip pad is 154-250 μm.