Packaging structure of laser radar chip, laser radar and packaging method

Abstract

The invention relates to the technical field of packaging structures, and discloses a packaging structure of a laser radar chip, a laser radar and a packaging method.The packaging structure comprises a packaging tube shell, a first adapter plate, a first silicon optical chip, a refractive index matching layer, a second adapter plate and a second silicon optical chip; the first adapter plate is fixedly arranged at the bottom of the packaging tube shell; first emergent antennas are arranged on the first surface of the first silicon optical chip in an array mode, and the surface, opposite to the first surface, of the first silicon optical chip is fixedly arranged on the first adapter plate. The second surface of the second silicon optical chip is provided with second emergent antennas arranged in an array, the second surface is fixed on the first surface through a refractive index matching layer, the first surface and the second surface are arranged in a staggered manner, and the emergent end surface of the second silicon optical chip is flush with the emergent end surface of the first silicon optical chip; the second adapter plate is fixedly connected with the surface, opposite to the second surface, of the second silicon optical chip. The number of channels of the laser radar emitting antenna can be increased.

Description

Technical Field

[0001] The present invention relates to the technical field of packaging structures, and in particular to a packaging structure of a laser radar chip, a laser radar and a packaging method. Background Art

[0002] LiDAR is a radar system that emits laser beams to detect the position, speed and other characteristic quantities of a target. It is a scanning laser ranging sensor that can be used in fields such as autonomous driving, robotics, industrial manufacturing, and aerospace.

[0003] For on-chip LiDARs integrated with silicon photonic chips, their output antennas are usually distributed in a one-dimensional linear array due to the limitations of planar waveguide processing technology. In order to avoid mutual crosstalk between antennas or for solid-state scanning application scenarios such as phased arrays, a certain spacing distance needs to be met between the output antennas. As the number of antenna channels gradually increases, the overall lateral size of the antenna light-emitting surface will need to gradually increase, and the edge channels will be increasingly affected by lens aberrations, resulting in a decrease in coupling efficiency and ultimately a decrease in detection distance, and even becoming unusable after reaching a certain level, limiting the final number of antenna channels for on-chip LiDARs integrated with silicon photonic chips. Summary of the invention

[0004] In view of this, the present invention provides a packaging structure of a laser radar chip, a laser radar and a packaging method to improve the problem of the final limited number of antenna channels of an on-chip laser radar integrated with a silicon photonic chip.

[0005] In the first aspect, the present invention provides a packaging structure of a laser radar chip, the packaging structure comprising a packaging tube shell, a first adapter plate, a first silicon photonic chip, a refractive index matching layer, a second adapter plate and a second silicon photonic chip; the first adapter plate is fixedly arranged at the bottom of the packaging tube shell, and the metal electrode on the first adapter plate is connected to the corresponding pin of the packaging tube shell through a wire; the first surface of the first silicon photonic chip has a first output antenna arranged in an array, the surface of the first silicon photonic chip opposite to the first surface is fixedly arranged on the first adapter plate, and the metal electrode on the first surface and the metal electrode on the first adapter plate are connected through a wire; the second surface of the second silicon photonic chip has a second output antenna arranged in an array, the second surface is fixed to the first surface through a refractive index matching layer, the first surface and the second surface are staggered to expose the metal electrode on the second surface, and the output end face of the second silicon photonic chip is flush with the output end face of the first silicon photonic chip; the second adapter plate is fixedly connected to the surface of the second silicon photonic chip opposite to the second surface, the metal electrode on the second adapter plate is connected to the metal electrode on the second surface through a wire, and the metal electrode on the second adapter plate is connected to the corresponding pin of the packaging tube shell through a wire.

[0006] The packaging structure of the laser radar chip provided by the present invention, without changing the existing silicon photonic chip process, forms a two-dimensional array laser radar output antenna arrangement by overlapping and bonding two or even more layers of silicon photonic chips, thereby multiplying the number of channels of the laser radar output antenna, which is beneficial to the subsequent improvement of the laser radar point frequency capability.

[0007] In an optional embodiment, a first groove structure is provided at the light entrance position of the first surface, and a second groove structure is provided at the light entrance position of the second surface; the first optical fiber is placed in the first groove structure to couple with the optical waveguide structure of the first silicon photonic chip to transmit the first laser signal to the first silicon photonic chip; the second optical fiber is placed in the second groove structure to couple with the optical waveguide structure of the second silicon photonic chip to transmit the second laser signal to the second silicon photonic chip.

[0008] In this embodiment, the groove structure can provide precise positioning for the coupling between the optical fiber and the optical waveguide, so that the laser signal output by the optical fiber can enter the optical waveguide with a higher coupling efficiency, thereby improving the transmission quality of the optical signal.

[0009] In an optional implementation, the wavelengths of the first laser signal and the second laser signal range from 1300 nm to 1700 nm, and the refractive index of the refractive index matching layer ranges from 1.4 to 1.5.

[0010] In an optional embodiment, a cross section of the first groove structure and a cross section of the second groove structure are V-shaped.

[0011] In an optional embodiment, the thickness of the refractive index matching layer is greater than or equal to 10 μm.

[0012] In an optional embodiment, the packaging structure also includes a third silicon photonic chip and a third adapter board; the third adapter board is fixedly disposed on a side surface of the second adapter board away from the second silicon photonic chip, and the metal electrodes on the third adapter board are connected to the corresponding pins of the packaging tube shell through wires; the third surface of the third silicon photonic chip has a third output antenna arranged in an array, and the surface of the third silicon photonic chip opposite to the third surface is fixedly disposed on the third adapter board, the metal electrodes on the third surface and the metal electrodes on the third adapter board are connected through wires, and the output end face of the third silicon photonic chip is flush with the output end face of the second silicon photonic chip.

[0013] In an optional embodiment, the first adapter plate is fixed to the bottom of the packaging tube shell by a bonding adhesive, and the surface of the first silicon photonic chip opposite to the first surface is fixed to the first adapter plate by a bonding adhesive.

[0014] In an optional implementation, the first adapter plate and the second adapter plate are aluminum nitride ceramic substrates.

[0015] In a second aspect, the present invention provides a laser radar, which includes a packaging structure of a laser radar chip according to the first aspect or any corresponding embodiment thereof.

[0016] In a third aspect, the present invention provides a packaging method for a laser radar chip, the packaging method comprising: providing a packaging tube shell, a first adapter board, a first silicon photonic chip, a second adapter board, and a second silicon photonic chip, wherein the first surface of the first silicon photonic chip has a first output antenna arranged in an array, and the second surface of the second silicon photonic chip has a second output antenna arranged in an array; fixing the first adapter board to the bottom of the packaging tube shell; connecting the metal electrodes on the first adapter board to the corresponding pins of the packaging tube shell through a wire through a wire bonding process; fixing the surface of the first silicon photonic chip opposite to the first surface on the first adapter board; connecting the metal electrodes on the first surface to the metal electrodes on the first adapter board through a wire bonding process. electrode; coating a refractive index matching glue on the first surface, and placing the second surface upside down on the first surface, wherein the refractive index matching glue is cured to form a refractive index matching layer, and the first surface and the second surface are staggered to expose the metal electrode on the second surface, and the output end face of the second silicon photonic chip is flush with the output end face of the first silicon photonic chip; fixing the second adapter plate on the surface of the second silicon photonic chip opposite to the second surface; connecting the metal electrode on the second adapter plate to the metal electrode on the second surface through a wire through a wire bonding process, and connecting the metal electrode on the second adapter plate to the corresponding pin of the packaging tube shell through a wire to obtain the packaging structure of the laser radar chip of the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the related technologies, the drawings required for use in the specific embodiments or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 is a schematic diagram of a packaging structure of a laser radar chip according to an embodiment of the present invention;

[0019] Figure 2 is a schematic diagram of a configuration of two silicon photonic chips according to an embodiment of the present invention;

[0020] Figure 3 is a schematic diagram of a connection method between an adapter board and a silicon photonic chip according to an embodiment of the present invention;

[0021] Figure 4 is a schematic diagram of a groove structure according to an embodiment of the present invention;

[0022] Figure 5 is a first schematic diagram of the connection relationship between the optical fiber and the optical waveguide structure according to an embodiment of the present invention;

[0023] Figure 6 is a schematic diagram of a packaging structure of another laser radar chip according to an embodiment of the present invention;

[0024] Figure 7 Schematic diagram of a packaging structure of another laser radar chip according to an embodiment of the present invention.

[0025] Figure numerals: 110, packaging tube shell; 120, first adapter board; 121, metal electrode; 122, wire; 130, first silicon photonic chip; 131, first output antenna; 132, optical waveguide structure; 133, first groove structure; 140, refractive index matching layer; 150, second adapter board; 160, second silicon photonic chip; 161, second output antenna; 162, second groove structure; 170, third silicon photonic chip; 171, third output antenna; 180, third adapter board; 210, first optical fiber; 220, second optical fiber. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0027] For on-chip LiDARs integrated with silicon photonic chips, due to the limitations of planar waveguide processing technology, the output antennas are usually distributed in a one-dimensional linear array, and the number of antenna channels can only be densely packed in one dimension. However, due to crosstalk between antennas, there is a physical minimum design spacing between antennas. Moreover, as the number of output antennas increases, the image plane size of the matching lens also needs to increase continuously. The edge channels will be more affected by lens aberrations, resulting in a decrease in coupling efficiency. Therefore, the number of antenna channels on silicon photonic chips is limited.

[0028] The present invention provides a packaging structure for a laser radar chip, which forms a two-dimensional array laser radar output antenna arrangement by overlapping and bonding two or more layers of silicon photonic chips, thereby increasing the number of channels of the laser radar output antenna.

[0029] The packaging structure of the laser radar chip provided by the present invention can be applied to frequency modulated continuous wave (FMCW) laser radar. FMCW laser radar is a technology that continuously modulates the frequency of the transmitted signal and uses the frequency difference (usually called beat frequency) between the detection light signal and the echo light signal to obtain target information (such as distance, speed, etc.). It has important applications in the fields of autonomous driving, robotics, industrial manufacturing, aerospace, etc.

[0030] The packaging structure of the laser radar chip provided by the present invention is described in detail below with reference to the accompanying drawings.

[0031] like Figures 1 to 3 As shown, the packaging structure of the laser radar chip provided by the present invention includes a packaging tube shell 110, a first adapter plate 120, a first silicon photonic chip 130, a refractive index matching layer 140, a second adapter plate 150 and a second silicon photonic chip 160.

[0032] Specifically, Figure 1 and Figure 2 As shown, the first silicon photonic chip 130 has a first surface and a fourth surface arranged opposite to each other, and a first output antenna 131 arranged in an array is arranged on the first surface. The second silicon photonic chip 160 also has a second surface and a fifth surface arranged opposite to each other, and a second output antenna 161 arranged in an array is arranged on the second surface. Figures 1 to 3 As shown, metal electrodes 121 are disposed on the first adapter plate 120 , the first silicon photonic chip 130 , the second adapter plate 150 and the second silicon photonic chip 160 .

[0033] exist Figure 1 In a cross-sectional view, the first surface and the fifth surface may be upper surfaces, and the second surface and the fourth surface may be lower surfaces, but the present invention is not limited thereto.

[0034] The first outgoing antenna 131 and the second outgoing antenna 161 are key components for signal transmission and reception, and are used to transmit the detection light signal generated by the light source module to the target object, and to receive the echo light signal (i.e., the detection light signal reflected from the target object), so that the laser radar can determine the relevant information of the target object (such as distance, speed, etc.). The number and distribution form of the first outgoing antenna 131 and the second outgoing antenna 161 are not limited in this application and can be determined by the designer according to the design requirements.

[0035] Specifically, the first adapter plate 120 is fixedly disposed on the bottom of the package tube shell 110, and the metal electrode on the first adapter plate 120 is connected to the corresponding pin of the package tube shell 110 through the wire 122. The surface of the first silicon photonic chip 130 opposite to the first surface is fixedly disposed on the first adapter plate 120, and the metal electrode on the first surface is connected to the metal electrode 121 on the first adapter plate 120 through the wire 122. The second surface of the second silicon photonic chip 160 is fixed to the first surface through the refractive index matching layer 140, and the first surface and the second surface are staggered to expose the metal electrode on the second surface, and the exit end face of the second silicon photonic chip 160 is flush with the exit end face of the first silicon photonic chip 130. The second adapter board 150 is fixedly connected to the surface of the second silicon photonic chip 160 opposite to the second surface, the metal electrode 121 on the second adapter board 150 is connected to the metal electrode 121 on the second surface through a wire 122, and the metal electrode 121 on the second adapter board 150 is connected to the corresponding pin of the packaging tube shell 110 through the wire 122.

[0036] That is to say, the first adapter plate 120, the first silicon photonic chip 130, the refractive index matching layer 140, the second silicon photonic chip 160 and the second adapter plate 150 are stacked from bottom to top, and the side surface of the first adapter plate 120 away from the first silicon photonic chip 130 is set at the bottom of the packaging tube shell 110, and the above-mentioned devices are electrically connected through a wire bonding process.

[0037] Moreover, if Figure 2 As shown, the surface of the first silicon photonic chip 130 provided with the first output antenna 131 and the surface of the second silicon photonic chip 160 provided with the second output antenna 161 are arranged opposite to each other and staggered to expose their respective metal electrodes.

[0038] The silicon photonic chip (i.e., the first silicon photonic chip 130 and the second silicon photonic chip 160) can integrate the complex optical devices and related electronic components of the laser radar on the same silicon-based substrate, such as optical amplifiers, optical couplers, and balanced detectors, etc., to reduce the size of the laser radar and improve the integration of the laser radar system. In addition, the silicon photonic chip has the characteristics of high bandwidth, low loss, and high-speed response, which can achieve higher data transmission rates and faster signal processing speeds, thereby improving the performance indicators of the laser radar such as ranging accuracy, resolution, and frame rate, so that it can perceive the surrounding environment more accurately.

[0039] The package shell 110 is a shell structure used to package electronic chips (such as silicon photonic chips, etc.), and is usually made of a variety of materials, including metals (such as copper, aluminum, etc.), ceramics, and plastics, etc. The shape and size vary depending on factors such as the type of packaged chip, application scenario, etc. The package shell 110 can provide a solid physical barrier for the chip to prevent the chip from being damaged by external mechanical forces such as collision, vibration, and impact. It can also isolate the chip from the external environment to prevent the chip from being corroded by harmful factors such as dust, moisture, and chemicals.

[0040] The package shell 110 is provided with pins or other electrical connection interfaces for electrically connecting the circuit inside the chip with an external circuit board or other electronic equipment. The layout of the pins can be determined by the designer according to requirements to ensure accurate transmission of the signal.

[0041] The refractive index matching layer 140 can be obtained by curing the refractive index matching glue, which is an adhesive used for bonding optical components. When materials with different refractive indices come into contact, light will be reflected and refracted at the interface, resulting in loss of optical signals and reduced transmission efficiency. The refractive index matching glue fills the gap between the two silicon photonic chips, and its refractive index is designed to be close to that of the adjacent optical material (such as the cladding layer of the silicon photonic chip), thereby reducing the reflection and refraction of light at the interface and improving the transmission efficiency of the optical signal.

[0042] The packaging structure of the laser radar chip provided by the present invention, without changing the existing silicon photonic chip process, forms a two-dimensional array laser radar output antenna arrangement by overlapping and bonding two or even more layers of silicon photonic chips, thereby multiplying the number of channels of the laser radar output antenna, which is beneficial to the subsequent improvement of the laser radar point frequency capability.

[0043] In this embodiment, the silicon photonic chip can be a passive chip. A passive chip may refer to a chip that does not contain active devices that can generate energy (such as light, electricity, etc.) inside the chip. The passive chip mainly transmits, couples, branches and filters optical signals and does not involve the generation of optical signals.

[0044] For example, Figure 3 As shown, the optical waveguide structure 132 on the silicon photonic chip can be devices such as an optical amplifier, an optical coupler, and a balanced detector. The optical amplifier can amplify the received optical signal, and the optical coupler can mix the local parameter optical signal generated based on the detection optical signal and the echo optical signal to obtain a mixed optical signal; the balanced detector can convert the mixed optical signal into an analog electrical signal, and the analog electrical signal is used to determine the distance between the target object and the silicon photonic chip.

[0045] The present invention does not limit the fixing method between the first adapter plate 120, the first silicon photonic chip 130, the second adapter plate 150 and the second silicon photonic chip 160. For example, they can be fixed by bonding or welding.

[0046] Optionally, the first adapter board 120 can be fixed to the bottom of the packaging tube shell 110 by bonding adhesive, the first silicon photonic chip 130 can also be fixed to the first adapter board 120 by bonding adhesive, and the second silicon photonic chip 160 can also be fixed to the second adapter board 150 by bonding adhesive.

[0047] Exemplarily, the first adapter plate 120 and the second adapter plate 150 may be aluminum nitride ceramic substrates, which have good thermal conductivity and low thermal expansion coefficient. Specifically, the middle of the first adapter plate 120 and the second adapter plate 150 may be a copper-plated layer, and a gold-tin thin film electrical circuit layer is provided on one surface.

[0048] Furthermore, if Figure 2 , Figures 3 to 5 As shown, a first groove structure 133 is disposed at the light entrance position of the first surface, and a second groove structure 162 is disposed at the light entrance position of the second surface.

[0049] Specifically, the first optical fiber 210 is placed in the first groove structure 133 and coupled with the optical waveguide structure 132 of the first silicon photonic chip 130 to transmit the first laser signal to the first silicon photonic chip 130. The second optical fiber 220 is placed in the second groove structure 162 and coupled with the optical waveguide structure of the second silicon photonic chip 160 to transmit the second laser signal to the second silicon photonic chip. Figure 3 Taking the structure of the first silicon photonic chip 130 as an example, the structure of the second silicon photonic chip 160 can be the same as Figure 3 The structure of the first silicon photonic chip 130 is the same.

[0050] In this embodiment, the groove structure can provide precise positioning for the coupling between the optical fiber and the optical waveguide, so that the laser signal output by the optical fiber can enter the optical waveguide with a higher coupling efficiency, thereby improving the transmission quality of the optical signal.

[0051] For example, the groove structure (ie, the first groove structure 133 and the second groove structure 162) can be realized by photolithography and etching process. The present invention does not limit the cross-sectional shape of the groove structure. Figure 4 and Figure 5 The V-shape is taken as an example, but is not limited thereto. For example, the cross-sectional shape of the groove structure may also be an arc or a rectangle.

[0052] Specifically, the cross-sections of the first groove structure 133 and the second groove structure 162 are set to be V-shaped, and the diameter of the inscribed circle of the V-shaped groove is the same as the diameter of the optical fiber. If the optical fiber is a standard SM-28e single-mode optical fiber, the diameter of the inscribed circle of the V-shaped groove can be 125 μm.

[0053] like Figure 5 As shown, one end of the first optical fiber 210 and the second optical fiber 220 can be tapered, and the tapered lens optical fiber can be placed inside the V-shaped groove, coupled with the optical waveguide structure, and fixed with glue. Setting the cross section of the groove structure to be V-shaped not only facilitates processing, but also improves the stability of fixation.

[0054] Optionally, the wavelengths of the first laser signal and the second laser signal may be in the range of 1300 nm to 1700 nm, and the refractive index of the refractive index matching layer 140 may be in the range of 1.4 to 1.5. For example, the wavelengths of the first laser signal and the second laser signal may be 1300 nm, 1310 nm, 1550 nm, or 1700 nm, etc., and in this case, the refractive index of the refractive index matching layer 140 may be 1.4, 1.42, 1.44, 1.45, 1.48, or 1.5, etc.

[0055] That is, when the wavelength of the laser signal is 1300nm-1700nm, the refractive index of the refractive index matching layer 140 can be 1.4-1.5 to ensure that the optical waveguide mode does not change. For example, when the wavelength of the laser signal is 1550nm, the refractive index matching layer 140 with a refractive index of 1.45 can be selected.

[0056] Exemplarily, the thickness of the refractive index matching layer is greater than or equal to 10 μm to prevent crosstalk between the output antennas on the first silicon photonic chip 130 and the second silicon photonic chip 160 .

[0057] The present invention does not limit the type of refractive index matching glue used to form the refractive index matching layer. For example, the refractive index matching glue may be a two-component A / B glue.

[0058] Specifically, two-component A / B glue is an adhesive composed of two different components (component A and component B). The two components have independent chemical properties when they are not mixed. When mixed in a certain proportion, a chemical reaction will occur, thereby curing to form a glue layer with adhesive strength. Component A can be a resin or polymer matrix, such as epoxy resin, polyurethane resin, etc. Component B can be a curing agent or cross-linking agent, which is used to react chemically with component A to promote the curing of the glue.

[0059] The number of silicon photonic chips in the packaging structure of the laser radar chip provided by the present invention can be three or more. The packaging structure of the laser radar chip is described below by taking the number of silicon photonic chips as three or four as an example.

[0060] like Figure 6 As shown, the packaging structure of the laser radar chip also includes a third silicon photonic chip 170 and a third adapter board 180 .

[0061] The third silicon photonic chip 170 has a third surface and a sixth surface arranged opposite to each other, and the third surface has a third output antenna 171 arranged in an array. Figure 6 From the perspective of, the third surface may be the upper surface of the third silicon photonic chip 170 , and the sixth surface may be the lower surface of the third silicon photonic chip 170 .

[0062] Specifically, the third adapter plate 180 is fixedly disposed on a side surface of the second adapter plate 150 away from the second silicon photonic chip 160, and the metal electrodes on the third adapter plate 180 are connected to corresponding pins of the package tube shell 110 through wires. The surface of the third silicon photonic chip 170 opposite to the third surface is fixedly disposed on the third adapter plate 180, and the metal electrodes on the third surface are connected to the metal electrodes on the third adapter plate 180 through wires, and the emission end face of the third silicon photonic chip 170 is flush with the emission end face of the second silicon photonic chip 160.

[0063] like Figure 7 As shown, the packaging structure of the laser radar chip includes two first adapter plates 120, two first silicon photonic chips 130, two refractive index matching layers 140, two second adapter plates 150 and two second silicon photonic chips 160.

[0064] Specifically, the first adapter plate 120, the first silicon photonic chip 130, the refractive index matching layer 140, the second silicon photonic chip 160 and the second adapter plate 150 are stacked from bottom to top as a group, and the first adapter plate 120 of one of the two groups is fixedly connected to the surface away from the first silicon photonic chip 130 and the second adapter plate 150 of the other group is fixedly connected to the surface away from the second silicon photonic chip 160.

[0065] The present invention also provides a laser radar, which includes the packaging structure of the laser radar chip provided by any of the above embodiments.

[0066] The present invention also provides a packaging method for a laser radar chip, the packaging method comprising the following steps:

[0067] Step S101, providing a packaging tube shell, a first adapter board, a first silicon photonic chip, a second adapter board and a second silicon photonic chip.

[0068] The first surface of the first silicon photonic chip has first output antennas arranged in an array, and the second surface of the second silicon photonic chip has second output antennas arranged in an array.

[0069] Step S102: fix the first adapter plate to the bottom of the package shell.

[0070] Specifically, the first transfer board can be firmly fixed to the bottom of the package shell by heating and curing the die-bonding adhesive.

[0071] Step S103 , using a wire bonding process, the metal electrodes on the first transfer board are connected to corresponding pins of the package shell through wires.

[0072] Specifically, the metal electrodes on the first transfer board may be connected to the corresponding pins of the package shell by ultrasonic pressure welding.

[0073] Step S104 , fixing a surface of the first silicon photonic chip opposite to the first surface on the first adapter plate.

[0074] Specifically, the first silicon photonic chip can be fixed on the first adapter board by heating and curing the bonding adhesive.

[0075] Step S105 , connecting the metal electrode on the first surface to the metal electrode on the first transfer board through a wire bonding process.

[0076] Specifically, after the first silicon photonic chip is fixedly arranged on the first adapter plate, the metal electrode on the first surface can be connected to the metal electrode on the first adapter plate by ultrasonic pressure welding. The connection method can be as follows: Figure 3 shown.

[0077] Step S106, coating the first surface with a refractive index matching glue, and placing the second surface upside down on the first surface.

[0078] Among them, the refractive index matching glue is cured to form a refractive index matching layer, the first surface and the second surface are staggered to expose the metal electrode on the second surface, the output end face of the second silicon photonic chip is flush with the output end face of the first silicon photonic chip, and the refractive index matching glue needs to avoid the V-groove gap at the head of the tapered optical fiber to prevent affecting the optical waveguide mode of the silicon photonic chip.

[0079] Specifically, the refractive index of the refractive index matching glue is close to the refractive index of the cladding on the silicon photonic chip. The material of the silicon photonic chip cladding can be silicon dioxide (SiO2). The refractive index of the cladding is determined based on the wavelength of the laser signal transmitted by the silicon photonic chip. For example, when the wavelength of the laser signal transmitted by the silicon photonic chip is 1550nm, the refractive index of the refractive index matching glue can be 1.45.

[0080] Step S107 , fixing the second adapter plate on a surface of the second silicon photonic chip opposite to the second surface.

[0081] Specifically, the second silicon photonic chip can be fixed on the second adapter board by heating and curing the bonding adhesive.

[0082] Step S108, using a wire bonding process, connecting the metal electrodes on the second transfer board to the metal electrodes on the second surface through wires, and connecting the metal electrodes on the second transfer board to corresponding pins of the package shell through wires.

[0083] Exemplarily, the metal electrodes on the second surface may be connected to the metal electrodes on the second transfer board by ultrasonic welding, and the metal electrodes on the second transfer board may be connected to corresponding pins of the package shell by wire bonding.

[0084] Specifically, for the second adapter board, since the metal electrode is flipped, a through hole is required to extend the metal electrode to the upper surface of the second adapter board, and then a wire bonding process is used to wire the corresponding metal electrode to the corresponding pin of the outer packaging shell.

[0085] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0086] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0087] In the description of this specification, the description with reference to the terms "this embodiment", "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0088] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0089] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the present invention.

Claims

1. A packaging structure of a laser radar chip, characterized in that: The packaging structure includes a packaging tube shell, a first adapter plate, a first silicon photonic chip, a refractive index matching layer, a second adapter plate and a second silicon photonic chip; The first adapter board is fixedly arranged at the bottom of the package tube shell, and the metal electrodes on the first adapter board are connected to the corresponding pins of the package tube shell through wires; A first output antenna arranged in an array is provided on a first surface of the first silicon photonic chip, a surface of the first silicon photonic chip opposite to the first surface is fixedly arranged on the first adapter board, and a metal electrode on the first surface is connected to a metal electrode on the first adapter board via a wire; The second surface of the second silicon photonic chip has a second output antenna arranged in an array, the second surface is fixed to the first surface through the refractive index matching layer, the first surface and the second surface are staggered to expose the metal electrode on the second surface, and the output end face of the second silicon photonic chip is flush with the output end face of the first silicon photonic chip; The second adapter board is fixedly connected to the surface of the second silicon photonic chip opposite to the second surface, the metal electrode on the second adapter board is connected to the metal electrode on the second surface through a wire, and the metal electrode on the second adapter board is connected to the corresponding pin of the packaging tube shell through a wire.

2. The packaging structure according to claim 1, characterized in that: A first groove structure is provided at the light entrance position of the first surface, and a second groove structure is provided at the light entrance position of the second surface; A first optical fiber is placed in the first groove structure and coupled with the optical waveguide structure of the first silicon photonic chip to transmit a first laser signal to the first silicon photonic chip; The second optical fiber is placed in the second groove structure and coupled with the optical waveguide structure of the second silicon photonic chip to transmit the second laser signal to the second silicon photonic chip.

3. The packaging structure according to claim 2, characterized in that: The wavelengths of the first laser signal and the second laser signal range from 1300 nm to 1700 nm, and the refractive index of the refractive index matching layer ranges from 1.4 to 1.

5.

4. The packaging structure according to claim 2 or 3, characterized in that: The cross-sections of the first groove structure and the second groove structure are V-shaped.

5. The packaging structure according to any one of claims 1 to 3, characterized in that: The thickness of the refractive index matching layer is greater than or equal to 10 μm.

6. The packaging structure according to any one of claims 1 to 3, characterized in that: The packaging structure also includes a third silicon photonic chip and a third adapter board; The third adapter plate is fixedly arranged on a side surface of the second adapter plate away from the second silicon photonic chip, and the metal electrodes on the third adapter plate are connected to corresponding pins of the packaging tube shell through wires; The third surface of the third silicon photonic chip has a third output antenna arranged in an array, the surface of the third silicon photonic chip opposite to the third surface is fixedly set on the third adapter board, the metal electrode on the third surface and the metal electrode on the third adapter board are connected by a wire, and the output end face of the third silicon photonic chip is flush with the output end face of the second silicon photonic chip.

7. The packaging structure according to any one of claims 1 to 3, characterized in that: The first adapter plate is fixed to the bottom of the packaging tube shell by a bonding adhesive, and the surface of the first silicon photonic chip opposite to the first surface is fixed to the first adapter plate by a bonding adhesive.

8. The packaging structure according to any one of claims 1 to 3, characterized in that: The first adapter plate and the second adapter plate are aluminum nitride ceramic substrates.

9. A laser radar, characterized in that: The laser radar includes the packaging structure of the laser radar chip according to any one of claims 1 to 8.

10. A packaging method for a laser radar chip, characterized in that: The packaging method comprises: A packaging tube shell, a first adapter board, a first silicon photonic chip, a second adapter board, and a second silicon photonic chip are provided, wherein a first surface of the first silicon photonic chip has a first output antenna arranged in an array, and a second surface of the second silicon photonic chip has a second output antenna arranged in an array; The first adapter plate is fixedly disposed on the bottom of the packaging tube shell; By means of a wire bonding process, the metal electrodes on the first adapter board are connected to corresponding pins of the package tube shell through wires; Fixing a surface of the first silicon photonic chip opposite to the first surface on the first adapter plate; Connecting the metal electrode on the first surface to the metal electrode on the first adapter plate through a wire bonding process; Coating a refractive index matching glue on the first surface, and placing the second surface upside down on the first surface, wherein the refractive index matching glue is cured to form a refractive index matching layer, the first surface and the second surface are staggered to expose the metal electrode on the second surface, and the output end face of the second silicon photonic chip is flush with the output end face of the first silicon photonic chip; The second adapter plate is fixedly disposed on a surface of the second silicon photonic chip opposite to the second surface; Through a wire bonding process, the metal electrodes on the second adapter board are connected to the metal electrodes on the second surface through wires, and the metal electrodes on the second adapter board are connected to the corresponding pins of the packaging shell through wires to obtain the packaging structure of the laser radar chip described in any one of claims 1 to 8.

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