Optical sensor packaging structure with high rigidity and high stress support

Abstract

The invention discloses an optical sensor packaging structure with high rigidity and high stress support, which comprises a substrate and a chip packaged on the substrate through a plastic packaging material, and is characterized in that the chip is electrically connected with the substrate through a gold wire; the plastic package material comprises a single transparent plastic package material and an adjustable side rail which is circumferentially arranged at the edge of the single transparent plastic package material. The invention relates to the technical field of optical sensors, and can solve the technical problems of an optical sensor packaging structure in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of optical sensors, and particularly to an optical sensor packaging structure with high rigidity and high stress support. Background Art

[0002] Please refer to the attached Figure 1 , an optical sensor of the prior art includes a substrate 1 and a chip 3 encapsulated on the substrate 1 by a plastic encapsulant 2. The chip 3 is electrically connected to the substrate 1 through a gold wire 4. Among them, the substrate 1 includes a core board 11, conductive copper foils 12 coated on two surfaces of the core board 11, copper circuits 13 provided on the core board 11, and a fiberglass cloth 14 located inside the core board 11. Please refer to the attached Figure 2 , the plastic encapsulant 2 includes a transparent plastic encapsulant 21 and side rails 22 circumferentially arranged at the edge of the transparent plastic encapsulant 21.

[0003] The optical sensor packaging structure of the prior art has the following technical problems: 1. Due to the high shrinkage rate of the transparent plastic encapsulant 21, the plastic encapsulant 2 is prone to warping under the influence of the encapsulation temperature, which affects the packaging quality of the optical sensor and also causes the optical sensor to be unable to achieve automated packaging.

[0004] 2. In order to improve the warping problem of the plastic encapsulant 2, the plastic encapsulant 2 is usually designed in a strip shape with dimensions of 100 - 122 * 60 - 65 mm, and the thickness of the plastic encapsulant 2 is about 0.3 - 0.4 mm, with small dimensions and large thickness.

[0005] 3. Due to the warping deformation of the plastic encapsulant 2, when singulating the optical sensor after encapsulation, it is easy to cut off-center, resulting in product scrapping.

[0006] 4. Six transparent plastic encapsulants 21 are arranged in each plastic encapsulant 2, and side rails 22 are provided at the edges of every two transparent plastic encapsulants 21, as shown in the attached Figure 2 . The side rails 22 have two forms: a full copper sheet 221 or a grid-shaped copper sheet 222. Among them, the full copper sheet 221 has strong stress support, but its stress release performance is weak; the grid-shaped copper sheet 222 has strong stress release performance, but its stress support is weak, and it is impossible to balance stress release and stress support.

[0007] 5. The thickness of the core board 11 is 40 - 60 um, and the thickness of the substrate 1 is 100 - 130 um. The overall thickness of the optical sensor is large. The core board 11 uses a liquid-type solder mask ink and a dry film-type solder mask ink for solder masking, but its solder masking performance is poor and it is easy to deform during the chip soldering process.

[0008] Therefore, it is necessary to provide an optical sensor packaging structure with high rigidity and high stress support, which can solve the above technical problems. Summary of the Invention

[0009] The object of the present invention is to provide an optical sensor packaging structure with high rigidity and high stress support, which can solve the above technical problems.

[0010] The present invention is implemented as follows: An optical sensor packaging structure with high rigidity and high stress support, including a substrate and a chip encapsulated on the substrate by a plastic encapsulant, and the chip is electrically connected to the substrate through a gold wire; The plastic encapsulant includes a single-piece transparent plastic encapsulant and an adjustable side rail circumferentially arranged at the edge of the single-piece transparent plastic encapsulant.

[0011] The adjustable side rail is composed of several groups of side rail units connected in sequence; each group of side rail units includes a pair of longitudinal side rails, several fan-shaped side rails arranged on the pair of longitudinal side rails, and a horizontal side rail vertically arranged between the pair of longitudinal side rails; the horizontal side rail is arranged between two adjacent fan-shaped side rails, and adjacent groups of side rail units are connected through the horizontal side rail; Each fan-shaped side rail includes a fan bracket and several fan blades arranged on the fan bracket.

[0012] The arrangement angles of each fan-shaped side rail are the same, and several fan blades are symmetrically arranged on the fan bracket; the horizontal symmetry axes of several fan blades are parallel to the horizontal side rail, and the longitudinal symmetry axes of several fan blades are parallel to the longitudinal side rail.

[0013] Two adjacent fan-shaped side rails are arranged in the same direction, and several fan blades are symmetrically arranged on the fan bracket; the horizontal symmetry axes of several fan blades form an acute angle with the horizontal side rail, and the longitudinal symmetry axes of several fan blades form an acute angle with the longitudinal side rail.

[0014] Two adjacent fan-shaped side rails are arranged in the opposite direction, and several fan blades are symmetrically arranged on the fan bracket; the horizontal symmetry axes of several fan blades form an acute angle with the horizontal side rail, and the longitudinal symmetry axes of several fan blades form an acute angle with the longitudinal side rail.

[0015] A fan cover is covered on several fan blades.

[0016] The substrate includes a core board, fiberglass cloth arranged in the core board, conductive solder masks coated on both surfaces of the core board, and copper circuits arranged on the core board, and the core board is a cured resin with a thickness of 30um, and the thickness of the substrate is 80um.

[0017] The substrate includes a core board, double-layer fiberglass cloth arranged in the core board, conductive solder masks coated on both surfaces of the core board, and copper circuits arranged on the core board, and the core board is polypropylene with a thickness of 15um, and the thickness of the substrate is 80um.

[0018] The substrate described above includes a core board, conductive solder masks coated on both surfaces of the core board, and copper circuits provided on the core board. The core board is a resin-coated copper foil with a thickness of 10 um, and the thickness of the substrate is 60 um.

[0019] The conductive solder mask is formed by coating solder mask green paint or solder mask black paint on the surface of the core board.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1. Since the present invention is provided with a single-piece transparent encapsulant and adjustable side rails, different-direction stress support is provided and different-direction stresses are released through horizontal and vertical side rails, longitudinal side rails, and fan-shaped side rails arranged at different angles, thereby improving the warping problem of the encapsulant and the problems of cutting deviation and product rejection caused by warping. It has good adaptability to substrates with different thicknesses and encapsulants with different thicknesses and materials, can reduce the thickness of the encapsulant, increase the size of the transparent encapsulant, and reduce the packaging volume of the optical sensor, which is beneficial to improving the automation degree of the optical sensor packaging.

[0021] 2. Since the present invention is provided with a conductive solder mask, it can reduce the thickness of the core board while avoiding the deformation problem of the core board in the welding process, making the core board have a high Tg point, a low CTE point, and high rigidity, and has good adaptability to core boards of different materials, reducing the thickness of the substrate to 60 - 80 um, and further reducing the packaging volume of the optical sensor. Description of the Drawings

[0022] Figure 1 is a schematic structural diagram of an optical sensor packaging structure of the prior art; Figure 2 is a plan view of the encapsulant in the optical sensor packaging structure of the prior art; Figure 3 is a schematic structural diagram of an optical sensor packaging structure with high rigidity and high stress support of the present invention; Figure 4 is a plan view of the encapsulant in the optical sensor packaging structure with high rigidity and high stress support of the present invention; Figure 5 is a schematic diagram of the first embodiment of the adjustable side rail in the optical sensor packaging structure with high rigidity and high stress support of the present invention; Figure 6 is a schematic diagram of the second embodiment of the adjustable side rail in the optical sensor packaging structure with high rigidity and high stress support of the present invention; Figure 7 is a schematic diagram of the third embodiment of the adjustable side rail in the optical sensor packaging structure with high rigidity and high stress support of the present invention; Figure 8It is a schematic diagram of the fourth embodiment of the adjustable side rail in the optical sensor packaging structure with high rigidity and high stress support of the present invention; Figure 9 It is a schematic diagram of the first embodiment of the substrate in the optical sensor packaging structure with high rigidity and high stress support of the present invention; Figure 10 It is a schematic diagram of the second embodiment of the substrate in the optical sensor packaging structure with high rigidity and high stress support of the present invention; Figure 11 It is a schematic diagram of the third embodiment of the substrate in the optical sensor packaging structure with high rigidity and high stress support of the present invention.

[0023] In the figure, 1 is the substrate, 11 is the core board, 12 is the conductive copper foil, 13 is the copper circuit, 14 is the fiberglass cloth, 15 is the conductive solder mask surface, 2 is the encapsulant, 21 is the transparent encapsulant, 22 is the side rail, 221 is the all-copper sheet, 222 is the grid-shaped copper sheet, 23 is the single-piece transparent encapsulant, 24 is the adjustable side rail, 240 is the longitudinal side rail, 241 is the fan-shaped side rail, 242 is the horizontal and vertical side rail, 243 is the fan bracket, 244 is the fan blade, 245 is the fan cover, 3 is the chip, and 4 is the gold wire. Specific embodiments

[0024] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0025] Please refer to the attached Figure 3 , an optical sensor packaging structure with high rigidity and high stress support, including a substrate 1 and a chip 3 encapsulated on the substrate 1 through an encapsulant 2, and the chip 3 is electrically connected to the substrate 1 through a gold wire 4.

[0026] The packaging method and electrical connection method of the substrate 1, the encapsulant 2, the chip 3, and the gold wire 4 are the same as those in the prior art and will not be elaborated here. What is different between the optical sensor packaging structure with high rigidity and high stress support of the present invention and the prior art is: Please refer to the attached Figure 4 , the encapsulant 2 includes a single-piece transparent encapsulant 23 and an adjustable side rail 24 circumferentially arranged at the edge of the single-piece transparent encapsulant 21.

[0027] The stress release and stress support of the encapsulant 2 are improved through the adjustable side rail 24, and the thickness of the encapsulant 2 can be made smaller, reaching 0.2 mm. The size of the encapsulant 2 can be increased to 230~260*70~80 mm, which is about 60% larger than the traditional 100~122*60~65 mm. At the same time, the transparent encapsulant can be designed in a single-piece form without the need to be designed in the traditional six-piece form.

[0028] Please refer to the attached Figure 5 to the attached Figure 8, the adjustable side rail 24 is formed by sequentially connecting several groups of side rail units; each group of side rail units includes a pair of longitudinal side rails 240, several fan-shaped side rails 241 arranged on the pair of longitudinal side rails 240, and a horizontal side rail 242 vertically arranged between the pair of longitudinal side rails 240; the horizontal side rail 242 is arranged between two adjacent fan-shaped side rails 241, and adjacent two groups of side rail units are connected by the horizontal side rail 242.

[0029] The pair of longitudinal side rails 240, the fan-shaped side rails 241, and the horizontal side rail 242 can provide stress supports in different directions and have better resistance during material expansion and contraction, thereby effectively improving the stress support of the encapsulant 2. At the same time, the stress can be effectively released through the setting of the fan-shaped side rails 241. By arranging the fan-shaped side rails 241 at different angles, it can adapt to substrates 1 with different thicknesses and the thermal expansion coefficients of encapsulants 2 with different thicknesses and materials, thereby overcoming the warping problem of the encapsulant 2.

[0030] Please refer to Appendix Figure 5 to Appendix Figure 7 , each of the fan-shaped side rails 241 includes a fan bracket 243 and several fan blades 244 arranged on the fan bracket 243.

[0031] Preferably, there are four fan blades 244, and the four fan blades 244 are arranged in central symmetry, that is, the included angle between the central axes of two adjacent fan blades 244 is 90°.

[0032] Please refer to Appendix Figure 5 , as a first preferred embodiment, the arrangement angles of each of the fan-shaped side rails 241 are the same, and several fan blades 244 are symmetrically arranged on the fan bracket 243; the horizontal symmetry axes of several fan blades 244 are parallel to the horizontal side rail 242, and the vertical symmetry axes of several fan blades 244 are parallel to the longitudinal side rails 240.

[0033] The stress in the horizontal and vertical directions can be effectively released through the arrangement of the four upper, lower, left, and right fan blades 244. Through the combination of the horizontal side rail 242 and the four fan blades 244, both high stress release and high stress support are taken into account to improve the warping problem of the encapsulant 2.

[0034] Please refer to Appendix Figure 6 , as a second preferred embodiment, two adjacent fan-shaped side rails 241 are arranged in the same direction, and several fan blades 244 are symmetrically arranged on the fan bracket 243; the horizontal symmetry axes of several fan blades 244 form an acute angle with the horizontal side rail 242, and the vertical symmetry axes of several fan blades 244 form an acute angle with the longitudinal side rails 240.

[0035] Compared with the first embodiment, in this embodiment, one fan-shaped side rail 241 is arranged to deflect to the right by a certain angle, and the other fan-shaped side rail 241 is arranged to deflect to the left by a certain angle. The deflection angles of the two fan-shaped side rails 241 can be adaptively adjusted according to actual requirements, so as to effectively release stresses in different directions and adapt to the coefficients of thermal expansion of substrates 1 with different thicknesses and encapsulants 2 with different thicknesses and materials, thereby better improving the warping problem of the encapsulant 2.

[0036] Please refer to the attached Figure 7 , as the third preferred embodiment, the adjacent two fan-shaped side rails 241 are arranged in opposite directions, and several fan blades 244 are symmetrically arranged on the fan bracket 243; the horizontal symmetry axes of the several fan blades 244 form an acute angle with the horizontal straight side rail 242, and the vertical symmetry axes of the several fan blades 244 form an acute angle with the vertical side rail 240.

[0037] Compared with the first embodiment, in this embodiment, the two fan-shaped side rails 241 are arranged to deflect to the right by a certain angle. The rotation angles of the two fan-shaped side rails 241 can be the same or different. The deflection angles of the two fan-shaped side rails 241 can be adaptively adjusted according to actual requirements, so as to effectively release stresses in different directions and adapt to the coefficients of thermal expansion of substrates 1 with different thicknesses and encapsulants 2 with different thicknesses and materials, thereby better improving the warping problem of the encapsulant 2.

[0038] Please refer to the attached Figure 8 , a fan cover 245 is covered on the several fan blades 244.

[0039] Through the setting of the fan cover 245, the stress support of the adjustable side rail 24 can be further improved.

[0040] Please refer to the attached Figure 9 , as the first preferred embodiment, the substrate 1 includes a core board 11, a fiberglass cloth 14 arranged in the core board 11, conductive solder mask layers 15 coated on two surfaces of the core board 11, and copper circuits 13 arranged on the core board 11. The core board 11 is a cured resin with a thickness of 30 um, and the thickness of the substrate 1 is 80 um.

[0041] Through the setting of the conductive solder mask layers 15, the solder mask performance of the core board 11 can be improved, the deformation of the core board 11 during the chip soldering process can be avoided, and the thickness of the core board 11 can be reduced from 40 - 60 um in the prior art to 30 um, so that the thickness of the substrate 1 can be thinner, reaching 80 um, and the packaging volume of the optical sensor is reduced.

[0042] Please refer to the attached Figure 10, as a second preferred embodiment, the substrate 1 includes a core board 11, a double-layer fiberglass cloth 14 disposed within the core board 11, conductive solder mask surfaces 15 coated on two surfaces of the core board 11, and copper traces 13 disposed on the core board 11. The core board 11 is made of polypropylene (PP) with a thickness of 15 μm, and the thickness of the substrate 1 is 80 μm.

[0043] By providing the conductive solder mask surfaces 15, the solder mask performance of the core board 11 can be improved, preventing the core board 11 from deforming during the chip soldering process. The core board 11 is formed by using PP material and the double-layer fiberglass cloth 14. While ensuring the strength of the core board 11, the thickness of the core board 11 can be reduced from 40 - 60 μm in the prior art to 15 μm, enabling the thickness of the substrate 1 to be thinner, reaching 80 μm, and reducing the packaging volume of the optical sensor.

[0044] Please refer to the attached Figure 11 , as a third preferred embodiment, the substrate 1 includes a core board 11, conductive solder mask surfaces 15 coated on two surfaces of the core board 11, and copper traces 13 disposed on the core board 11. The core board 11 is resin-coated copper foil (RCC) with a thickness of 10 μm, and the thickness of the substrate 1 is 60 μm.

[0045] By providing the conductive solder mask surfaces 15, the solder mask performance of the core board 11 can be improved, preventing the core board 11 from deforming during the chip soldering process. By using RCC material, while ensuring the strength of the core board 11, the thickness of the core board 11 can be reduced from 40 - 60 μm in the prior art to 10 μm, and there is no need to arrange the fiberglass cloth 14, enabling the thickness of the substrate 1 to be thinner, reduced to 60 μm, and further reducing the packaging volume of the optical sensor.

[0046] The conductive solder mask surfaces 15 are formed by coating solder mask green paint or solder mask black paint on the surface of the core board 11.

[0047] Taking the core board with a thickness of 30um as an example, compared with the core boards using liquid solder mask ink and dry film solder mask ink in the prior art, the core board 11 with a conductive solder mask surface 15 of the present invention has a higher glass transition temperature (tg point), coefficient of thermal expansion (CTE point), and rigidity (Modulus). Specifically, the tg point of the core board using liquid solder mask ink is 100 Deg.C, the tg point of the core board using dry film solder mask ink is 110 - 140 Deg.C, and the tg point of the core board 11 of the present invention is 260 Deg.C; the CTE point of the core board using liquid solder mask ink is 60 ppm / deg.C, the CTE point of the core board using dry film solder mask ink is 40 - 50 ppm / deg.C, and the CTE point of the core board 11 of the present invention is 15 ppm / deg.C; the Modulus of the core board using liquid solder mask ink is 2.4 Gpa, the Modulus of the core board using dry film solder mask ink is 3.2 - 4 Gpa, and the Modulus of the core board 11 of the present invention is 15 Gpa. Therefore, the core board 11 of the present invention has better solder mask performance compared with the core boards in the prior art.

[0048] Through the improvement of the substrate 1 (60 - 80um) and the encapsulant 2 (0.2mm) of the present invention, the total thickness of the optical sensor can be controlled within 0.3mm, achieving an ultra-thin optical sensor without warping and deformation problems.

[0049] The above are only the preferred embodiments of the present invention and are not used to limit the protection scope of the invention. Therefore, any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A light sensor packaging structure with high rigidity and high stress support, comprising a substrate (1) and a chip (3) encapsulated on the substrate (1) by a molding compound (2), and the chip (3) is electrically connected to the substrate (1) through a gold wire (4). It is characterized in that: The molding compound (2) includes a single-piece transparent molding compound (23) and an adjustable side rail (24) circumferentially arranged at the edge of the single-piece transparent molding compound (21).

2. The high-rigidity and high-stress-supported optical sensor packaging structure according to claim 1, wherein: The adjustable side rail (24) is composed of several groups of side rail units connected in sequence; each group of side rail units includes a pair of longitudinal side rails (240), several fan-shaped side rails (241) arranged on the pair of longitudinal side rails (240), and a horizontal straight side rail (242) vertically arranged between the pair of longitudinal side rails (240); the horizontal straight side rail (242) is arranged between two adjacent fan-shaped side rails (241), and adjacent groups of side rail units are connected through the horizontal straight side rail (242). Each fan-shaped side rail (241) includes a fan bracket (243) and several fan blades (244) arranged on the fan bracket (243).

3. The high-rigidity and high-stress-supported optical sensor packaging structure according to claim 2, characterized in that: The arrangement angles of each fan-shaped side rail (241) are the same, and several fan blades (244) are symmetrically arranged on the fan bracket (243); the transverse symmetry axis of several fan blades (244) is parallel to the horizontal straight side rail (242), and the longitudinal symmetry axis of several fan blades (244) is parallel to the longitudinal side rail (240).

4. The high-rigidity and high-stress-supported optical sensor packaging structure according to claim 2, wherein: Two adjacent fan-shaped side rails (241) are arranged in the same direction, and several fan blades (244) are symmetrically arranged on the fan bracket (243); the transverse symmetry axis of several fan blades (244) forms an acute angle with the horizontal straight side rail (242), and the longitudinal symmetry axis of several fan blades (244) forms an acute angle with the longitudinal side rail (240).

5. The high-rigidity and high-stress-supported optical sensor packaging structure according to claim 2, wherein: Two adjacent fan-shaped side rails (241) are arranged in the opposite direction, and several fan blades (244) are symmetrically arranged on the fan bracket (243); the transverse symmetry axis of several fan blades (244) forms an acute angle with the horizontal straight side rail (242), and the longitudinal symmetry axis of several fan blades (244) forms an acute angle with the longitudinal side rail (240).

6. The high-rigidity and high-stress-supported optical sensor packaging structure according to any one of claims 2-5, characterized in that: A fan cover (245) is covered on the several fan blades (244).

7. The optical sensor packaging structure with high rigidity and high stress support according to claim 1, characterized in that: The substrate (1) includes a core board (11), a glass fiber cloth (14) arranged in the core board (11), conductive solder masks (15) coated on two surfaces of the core board (11), and copper circuits (13) arranged on the core board (11), and the core board (11) is a cured resin with a thickness of 30um, and the thickness of the substrate (1) is 80um.

8. The high-rigidity and high-stress-supported optical sensor packaging structure according to claim 1, wherein: The substrate (1) includes a core board (11), a double-layer glass fiber cloth (14) arranged in the core board (11), conductive solder masks (15) coated on two surfaces of the core board (11), and copper circuits (13) arranged on the core board (11), and the core board (11) is a polypropylene with a thickness of 15um, and the thickness of the substrate (1) is 80um.

9. The high-rigidity and high-stress-supported optical sensor packaging structure according to claim 1, wherein: The substrate (1) described above includes a core board (11), conductive solder mask surfaces (15) coated on both surfaces of the core board (11), and copper circuits (13) provided on the core board (11). The core board (11) is a resin-coated copper foil with a thickness of 10 um, and the thickness of the substrate (1) is 60 um.

10. The high-rigidity and high-stress-supported optical sensor packaging structure according to any one of claims 7-9, characterized in that: The conductive solder mask surface (15) is formed by coating the surface of the core board (11) with solder mask green paint or solder mask black paint.

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