Thin film light-transmitting bead black light sensor ToF packaging structure

Abstract

The invention discloses a thin film light-transmitting bead black light sensor ToF packaging structure which comprises a substrate, a vertical cavity surface emitting laser, an ASIC chip, black plastic packaging glue and light-transmitting beads. The vertical cavity surface emitting laser and the ASIC chip are arranged on the substrate and are electrically connected with the substrate through routing, and light-transmitting beads are arranged on a first emitting end of the vertical cavity surface emitting laser and a first receiving end of the ASIC chip; the black plastic packaging adhesive is packaged on the vertical cavity surface emitting laser, the ASIC chip and the light-transmitting beads, the tops of the two light-transmitting beads protrude out of the top surface of the black plastic packaging adhesive, and the black plastic packaging adhesive forms an isolation retaining wall between the vertical cavity surface emitting laser and the ASIC chip, so that light emitted by the vertical cavity surface emitting laser penetrates through the light-transmitting beads and then is emitted out. The ASIC chip receives the reflected light passing through the light-transmitting bead. The invention relates to the technical field of semiconductor packaging, and can solve the technical problems of a traditional transparent optical sensor packaging structure.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor packaging, and in particular to a thin-film light-transmitting bead black light sensor ToF packaging structure. Background Art

[0002] TOF packaging refers to the packaging form of a TOF sensor, which is mainly used to package the sensor in 3D depth imaging technology. Please refer to the attached Figure 1 , a traditional TOF packaging structure includes a substrate 1, a light-emitting chip 2, a light-receiving chip 3, a transparent encapsulant 4, and a cover body 5; the light-emitting chip 2 and the light-receiving chip 3 are respectively arranged on the substrate 1 and electrically connected to the substrate 1 by wire bonding, and the transparent encapsulant 4 encapsulates the light-emitting chip 2 and the light-receiving chip 3 on the substrate 1; the cover body 5 is installed on the substrate 1 and covers the light-emitting chip 2, the light-receiving chip 3, and the transparent encapsulant 4. A baffle 51 for isolating the light-emitting chip 2 from the light-receiving chip 3 is provided in the cover body 5, and the bottom of the baffle 51 is bonded to the substrate 1 by DAM glue 52 (Dual Adhesive Material, a material used for packaging electronic components, composed of various materials such as resin, filler, adhesive, and additives), and a through hole 53 for light emission and reception is provided at the top of the cover body 5 above the light-emitting chip 2 and the light-receiving chip 3.

[0003] The traditional TOF packaging structure has the following technical problems:

[0004] 1. The transparent encapsulant has a high shrinkage rate and is prone to deformation due to high temperature during processing, resulting in a quality defect of chip warping.

[0005] 2. When the cover body is bonded by DAM glue, there is a problem of glue overflow, and the bonding position is prone to light transmission, so that the baffle cannot ensure 100% light blocking effect, resulting in the light of the light-emitting chip being easily directly transmitted to the light-receiving chip through the DAM glue, affecting the sensitivity of the light-emitting chip and the light-receiving chip; in addition, the cost of bonding with DAM glue is relatively high.

[0006] 3. The cover body, its baffle, and through hole need to be cut and processed into shape, and there are quality defects such as burrs (the burrs are about 30 - 100um) on the cutting surface.

[0007] Therefore, it is necessary to provide a thin-film light-transmitting bead black light sensor ToF packaging structure that can solve the above technical problems. Summary of the Invention

[0008] The purpose of the present invention is to provide a thin-film light-transmitting bead black light sensor ToF packaging structure that can solve the above technical problems.

[0009] The present invention is implemented as follows:

[0010] A thin-film light-transmitting bead black light sensor ToF packaging structure, comprising a substrate, a vertical cavity surface emitting laser, an ASIC chip, black encapsulant, and light-transmitting beads; the vertical cavity surface emitting laser and the ASIC chip are arranged on the substrate and are electrically connected to the substrate by wire bonding, and light-transmitting beads are provided on the first emitting end of the vertical cavity surface emitting laser and the first receiving end of the ASIC chip; the black encapsulant encapsulates the vertical cavity surface emitting laser, the ASIC chip, and the light-transmitting beads, and the tops of the two light-transmitting beads respectively protrude from the top surface of the black encapsulant. The black encapsulant forms an isolation barrier wall between the vertical cavity surface emitting laser and the ASIC chip, so that the light emitted from the first emitting end of the vertical cavity surface emitting laser passes through the light-transmitting bead and then emits out, and the first receiving end of the ASIC chip receives the reflected light passing through the light-transmitting bead.

[0011] A reflection cavity is formed in the black encapsulant. The vertical cavity surface emitting laser is located in the reflection cavity, and the light-transmitting bead on the top of the vertical cavity surface emitting laser and part of the ASIC chip are located in the reflection cavity; a reflection layer is provided on the top surface of the reflection cavity, and the light emitted from the second emitting end of the vertical cavity surface emitting laser is reflected by the reflection layer to the second receiving end of the ASIC chip located in the reflection cavity.

[0012] The isolation barrier wall formed by the black encapsulant is located between the first receiving end and the second receiving end of the ASIC chip.

[0013] A filter film is provided on the top of the light-transmitting bead located above the ASIC chip.

[0014] An antireflection layer is provided on the top of the light-transmitting bead located above the ASIC chip, and the antireflection layer is located on the top of the filter film.

[0015] The first receiving end of the ASIC chip is bonded to the bottom of the light-transmitting bead by transparent glue, and the bottom of the ASIC chip is bonded to the substrate by DAF glue.

[0016] The first emitting end of the vertical cavity surface emitting laser is bonded to the bottom of the light-transmitting bead by transparent glue, and the bottom of the vertical cavity surface emitting laser is bonded to the substrate by epoxy resin glue.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. Since the present invention is provided with a black plastic encapsulant, its shrinkage rate is lower than that of traditional transparent plastic encapsulants. It can effectively avoid the quality defect of chip warping in the high-temperature encapsulation process, and at the same time can form a natural light barrier with 100% light shielding, that is, an isolation barrier wall, between the first receiving end and the second receiving end of the ASIC chip, effectively preventing the light emitted by the vertical cavity surface emitting laser from directly hitting the first receiving end of the ASIC chip. Moreover, the black plastic encapsulant is directly molded without the need to set a cover and bond it to the substrate with DAM glue, which can reduce the anti-collision cost, avoid the problem of DAM glue overflow and the burr problem in the cutting process of the cover, and improve the ToF encapsulation quality of the optical sensor.

[0019] 2. Since the present invention is provided with a light-transmitting bead made of transparent glass in a spherical or ellipsoidal structure, the top of the light-transmitting bead protrudes from the black plastic encapsulant, which can achieve a more stable light-receiving and light-emitting effect while ensuring the light emission of the vertical cavity surface emitting laser and the light reception of the ASIC chip, improving the quality of the ToF encapsulation structure of the optical sensor, and without the need to set a cover and its through holes, further avoiding the burr problem in the cutting process of the cover.

[0020] 3. Since the present invention is provided with a filter film and an antireflection layer, it can filter the light received by the ASIC chip to achieve the function of receiving light with a specific wavelength, and ensure the light-receiving stability of the ASIC chip, improving the functionality of the ToF encapsulation structure of the optical sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic structural diagram of a traditional optical sensor encapsulation structure;

[0022] Figure 2 is a schematic structural diagram of the ToF encapsulation structure of the thin-film light-transmitting bead black optical sensor of the present invention.

[0023] In the figure, 1 is the substrate, 2 is the light-emitting chip, 3 is the light-receiving chip, 4 is the transparent plastic encapsulant, 5 is the cover, 51 is the barrier wall, 52 is the DAM glue, 53 is the through hole, 6 is the vertical cavity surface emitting laser, 7 is the ASIC chip, 8 is the black plastic encapsulant, 80 is the isolation barrier wall, 81 is the reflection cavity, 82 is the reflection layer, 9 is the light-transmitting bead, 10 is the filter film, 11 is the antireflection layer, 12 is the transparent glue, 13 is the DAF glue, 14 is the epoxy resin glue. DETAILED DESCRIPTION OF THE INVENTION

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

[0025] Please refer to the attached Figure 2, a thin-film light-transmitting bead black light sensor ToF packaging structure, including a substrate 1, a vertical cavity surface emitting laser 6, an ASIC chip (Application Specific Integrated Circuit, an ASIC chip is an integrated circuit chip for specific applications) 7, a black encapsulant 8, and a light-transmitting bead 9; the vertical cavity surface emitting laser 6 and the ASIC chip 7 are arranged on the substrate 1 and are electrically connected to the substrate 1 through wire bonding. Light-transmitting beads 9 are provided on the first emission end of the vertical cavity surface emitting laser 6 and the first receiving end of the ASIC chip 7; the black encapsulant 8 encapsulates the vertical cavity surface emitting laser 6, the ASIC chip 7, and the light-transmitting beads 9, and the tops of the two light-transmitting beads 9 respectively protrude from the top surface of the black encapsulant 8. The black encapsulant 8 forms an isolation barrier 80 between the vertical cavity surface emitting laser 6 and the ASIC chip 7, so that the light emitted from the first emission end of the vertical cavity surface emitting laser 6 passes through the light-transmitting bead 9 and then emits, and the first receiving end of the ASIC chip 7 receives the reflected light passing through the light-transmitting bead 9.

[0026] Preferably, the black encapsulant 8 is made of black EMC material (Epoxy Molding Compound, which is a thermosetting chemical material used for semiconductor packaging). By using the black encapsulant 8 for light sensor ToF packaging, the shrinkage rate is low. Compared with traditional transparent encapsulant materials, it can effectively reduce the shrinkage rate in the high-temperature packaging processing process, thus avoiding the quality defect of chip warping.

[0027] At the same time, the black EMC material is opaque, and the black encapsulant 8 is directly molded. Compared with the barrier wall in the traditional cover, there is no need to bond with the substrate through DAM glue. Therefore, a natural light barrier that can block 100% of the light, that is, the isolation barrier 80, can be formed between the vertical cavity surface emitting laser 6 and the ASIC chip 7, avoiding the light emitted by the vertical cavity surface emitting laser 6 directly hitting the first receiving end of the ASIC chip 7, ensuring a 100% light-blocking effect, and reducing the packaging cost. It also avoids the problems of light transmission and glue overflow at the DAM glue and the cutting burr problem of the cover.

[0028] The light-transmitting bead 9 can be made of transparent glass. The shape of the light-transmitting bead 9 and the size of its top arc surface can be adaptively adjusted according to the light emission requirements of the vertical cavity surface emitting laser 6 and the light receiving requirements of the ASIC chip 7, so that the light emitted from the first emission end of the vertical cavity surface emitting laser 6 can pass through the light-transmitting bead 9 at its top and emit, and the reflected light can pass through the light-transmitting bead 9 at the top of the ASIC chip 7 and then be received by the first receiving end of the ASIC chip 7.

[0029] A reflection cavity 81 is formed in the black plastic encapsulant 8. The vertical cavity surface emitting laser 6 is located within the reflection cavity 81. The light-transmitting bead 9 at the top of the vertical cavity surface emitting laser 6 and the ASIC chip 7 are partially located within the reflection cavity 81. A reflective layer 82 is provided on the top surface of the reflection cavity 81. The light emitted from the second emission end of the vertical cavity surface emitting laser 6 is reflected by the reflective layer 82 onto the second receiving end of the ASIC chip 7 located within the reflection cavity 81.

[0030] Through the setting of the reflective layer 82, the light emitted from the second emission end of the vertical cavity surface emitting laser 6 can be directly reflected onto the second receiving end of the ASIC chip 7, as shown by the arrow in the attached Figure 2 The material and reflection angle of the reflective layer 82 can be adaptively adjusted according to the light emission requirements of the vertical cavity surface emitting laser 6 and the light receiving requirements of the ASIC chip 7 to meet the usage function requirements of the optical sensor.

[0031] The isolation barrier 80 formed by the black plastic encapsulant 8 is located between the first receiving end and the second receiving end of the ASIC chip 7.

[0032] The isolation barrier 80 is located between the first receiving end and the second receiving end of the ASIC chip 7 and is used to form a natural light barrier with 100% light blocking between the first receiving end and the second receiving end of the ASIC chip 7, ensuring that the light emitted from the two emission ends of the vertical cavity surface emitting laser 6 does not directly shine on the first receiving end of the ASIC chip 7, and the light emitted from the second emission end of the vertical cavity surface emitting laser 6 can be directly reflected onto the second receiving end of the ASIC chip 7, thus ensuring the independent emission and reception of the two beams of light without mutual interference.

[0033] A filter film 10 is provided on the top of the light-transmitting bead 9 located above the ASIC chip 7.

[0034] The filter film 10 is used to filter light so that the ASIC chip 7 only receives light of a specific wavelength. The filter film 10 can be adaptively selected according to the wavelength of the light required to be received by the ASIC chip 7 to ensure its filtering function and increase the functionality of the ToF package structure of the optical sensor.

[0035] An anti-reflection layer 11 is provided on the top of the light-transmitting bead 9 located above the ASIC chip 7. The anti-reflection layer 11 is located on top of the filter film 10.

[0036] The anti-reflection layer 11 can reduce the reflection of the light reflected onto the ASIC chip 7. The anti-reflection layer 11 can be adaptively selected according to the light receiving requirements of the ASIC chip 7, thereby improving the anti-reflection effect and the light receiving stability of the ASIC chip 7 for light of a specific wavelength.

[0037] The first receiving end of the ASIC chip 7 is bonded to the bottom of the light-transmitting bead 9 through the transparent adhesive 12, which ensures a reliable connection between the ASIC chip 7 and the light-transmitting bead 9 while not affecting the light-receiving effect of the reflected light passing through the light-transmitting bead 9 and being received by the first receiving end of the ASIC chip 7. The bottom of the ASIC chip 7 is bonded to the substrate 1 through the DAF (Die Attach Film, a high-performance adhesive film used for connecting chips and substrates in semiconductor packaging) 13, which ensures a reliable connection between the ASIC chip 7 and the substrate 1.

[0038] The first emitting end of the vertical cavity surface emitting laser 6 is bonded to the bottom of the light-transmitting bead 9 through the transparent adhesive 12, which ensures a reliable connection between the vertical cavity surface emitting laser 6 and the light-transmitting bead 9 while not affecting the light emitted from the first emitting end of the vertical cavity surface emitting laser 6 passing through the light-transmitting bead 9. The bottom of the vertical cavity surface emitting laser 6 is bonded to the substrate 1 through the epoxy resin adhesive (Epoxy adhesive) 14, which ensures a reliable connection between the vertical cavity surface emitting laser 6 and the substrate 1.

[0039] The light-transmitting bead 9 is of a spherical structure or an ellipsoidal structure, which improves the stability of light emission and reception.

[0040] 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 shall be included in the protection scope of the present invention.

Claims

1. A ToF package structure for a thin-film light-transmitting bead black light sensor, characterized in that: It includes a substrate (1), a vertical cavity surface emitting laser (6), an ASIC chip (7), a black plastic encapsulant (8) and a light-transmitting bead (9); the vertical cavity surface emitting laser (6) and the ASIC chip (7) are arranged on the substrate (1) and are electrically connected to the substrate (1) by wire bonding. Light-transmitting beads (9) are provided on both the first emission end of the vertical cavity surface emitting laser (6) and the first receiving end of the ASIC chip (7); the black plastic encapsulant (8) encapsulates the vertical cavity surface emitting laser (6), the ASIC chip (7) and the light-transmitting beads (9), and the tops of the two light-transmitting beads (9) protrude from the top surface of the black plastic encapsulant (8) respectively. The black plastic encapsulant (8) forms an isolation barrier (80) between the vertical cavity surface emitting laser (6) and the ASIC chip (7), so that the light emitted from the first emission end of the vertical cavity surface emitting laser (6) passes through the light-transmitting bead (9) and then exits, and the first receiving end of the ASIC chip (7) receives the reflected light passing through the light-transmitting bead (9).

2. The thin-film light-transmitting bead black light sensor ToF package structure according to claim 1, characterized in that: A reflection cavity (81) is formed in the black plastic encapsulant (8). The vertical cavity surface emitting laser (6) is located in the reflection cavity (81), and the light-transmitting bead (9) at the top of the vertical cavity surface emitting laser (6) and a part of the ASIC chip (7) are located in the reflection cavity (81); a reflection layer (82) is provided on the top surface of the reflection cavity (81), and the light emitted from the second emission end of the vertical cavity surface emitting laser (6) is reflected by the reflection layer (82) to the second receiving end of the ASIC chip (7) located in the reflection cavity (81).

3. The thin-film light-transmitting bead black light sensor ToF package structure according to claim 2, characterized in that: The isolation barrier (80) formed by the black plastic encapsulant (8) is located between the first receiving end and the second receiving end of the ASIC chip (7).

4. The thin-film light-transmitting bead black light sensor ToF package structure according to claim 1 or 2, characterized in that: A filter film (10) is provided on the top of the light-transmitting bead (9) located above the ASIC chip (7).

5. The thin-film light-transmitting bead black light sensor ToF package structure according to claim 4, characterized in that: An anti-reflection layer (11) is provided on the top of the light-transmitting bead (9) located above the ASIC chip (7), and the anti-reflection layer (11) is located on the top of the filter film (10).

6. The black light sensor ToF package structure of the thin film light-transmitting beads according to claim 1, characterized in that: The first receiving end of the ASIC chip (7) is bonded to the bottom of the light-transmitting bead (9) by a transparent adhesive (12), and the bottom of the ASIC chip (7) is bonded to the substrate (1) by a DAF adhesive (13).

7. The black light sensor ToF packaging structure of the thin film light-transmitting bead according to claim 1, characterized in that: The first emission end of the vertical cavity surface emitting laser (6) is bonded to the bottom of the light-transmitting bead (9) by a transparent adhesive (12), and the bottom of the vertical cavity surface emitting laser (6) is bonded to the substrate (1) by an epoxy resin adhesive (14).

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