A laser semiconductor chip packaging structure, a packaging method and an electronic device

Abstract

This application provides a laser semiconductor chip packaging structure, packaging method, and electronic device, relating to the field of packaging technology. In this packaging structure, a first substrate has through-holes; the height of the laser semiconductor chip and leads disposed in the through-holes of the first substrate and on a second substrate does not exceed the upper surface of the first substrate; the through-holes of the first substrate are filled with optical adhesive. The space formed in the through-holes of the first substrate accommodates the laser semiconductor chip and leads. Since the highest point of the leads remains below the upper surface of the substrate after wire bonding, it does not affect screen printing, component mounting, and reflow soldering. Therefore, wire bonding can be performed before reflow soldering, thereby avoiding the influence of flux residue after reflow soldering on the wire bonding process.

Description

Technical Field

[0001] This application relates to the field of packaging technology, and in particular to a laser semiconductor chip packaging structure, packaging method and electronic device. Background Technology

[0002] With the development of high-power semiconductor laser applications, such as their expanding use in the field of autonomous driving, higher requirements are being placed on the packaging quality of laser semiconductor chips and modules, considering the complex operating conditions in vehicles and the long life cycle of automotive products.

[0003] Currently, commonly used semiconductor lasers and semiconductor chips all require wire bonding for electrical and signal connections to the outside world. During the manufacturing process, solder paste needs to be screen-printed onto the surface of a printed circuit board (PCB) or substrate, followed by component mounting and reflow soldering.

[0004] Screen printing requires a flat PCB or substrate surface. Therefore, wire bonding cannot be performed on the PCB or substrate surface before screen printing. The usual practice is to first screen print solder paste, mount components, and perform reflow soldering, and then perform wire bonding.

[0005] However, solder paste contains flux or soldering agent, which volatilizes and leaves residues during reflow soldering. This can contaminate the lead bonding area, leading to a high lead bonding failure rate and poor reliability.

[0006] Furthermore, in terms of structure, the commonly used solutions in the market to protect laser semiconductor chips typically employ metal or plastic casings encapsulated with optical adhesives. On the one hand, this leads to additional packaging processes, increasing production costs; on the other hand, due to differences in material properties, under conditions such as thermal shock, thermal cycling, and random vibration, new reliability issues such as delamination and cracking often arise between the metal or plastic casing and the substrate.

[0007] Therefore, how to reliably package laser semiconductor chips is a technical problem that needs to be solved. Summary of the Invention

[0008] The purpose of this application is to provide a laser semiconductor chip packaging structure, an electronic device, and a laser semiconductor chip packaging method to solve the technical problem of how to reliably package laser semiconductor chips in the prior art.

[0009] To achieve the above objectives, the embodiments of this application adopt the following technical solutions.

[0010] In a first aspect, embodiments of this application provide a laser semiconductor chip packaging structure, including a substrate and an optical adhesive; the substrate includes a first substrate and a second substrate, which are stacked from top to bottom.

[0011] The first substrate has through holes; a laser semiconductor chip, leads, and conductor pads are disposed in the through holes of the first substrate and on the second substrate. The laser semiconductor chip is connected through the leads and conductor pads. The height of the laser semiconductor chip and the leads does not exceed the upper surface of the first substrate. Optical adhesive is filled in the through holes of the first substrate.

[0012] Optionally, adhesive pads are also provided in the through holes of the first substrate and on the second substrate, and the laser semiconductor chip is connected to the adhesive pads.

[0013] Optionally, the packaging structure also includes conductive silver paste, through which the laser semiconductor chip is connected to the bonding pad.

[0014] Optionally, the laser semiconductor chip, lead wire, conductive pad, and bonding pad each include two sets, which are arranged axially symmetrically.

[0015] Optionally, the two sets of laser semiconductor chips, leads, and conductive pads are arranged sequentially from the inside to the outside along the axis of symmetry.

[0016] Optionally, the substrate further includes a third substrate, and the first substrate, the second substrate and the third substrate are stacked from top to bottom, the second substrate has a through hole; a reflective element is provided in the through hole of the second substrate and on the third substrate.

[0017] Optionally, the orthographic projection of the through hole of the second substrate onto the upper surface of the first substrate is within the orthographic projection range of the through hole of the first substrate onto the upper surface of the first substrate.

[0018] Optionally, the upper surface of the reflector is higher than the upper surface of the first substrate, and the upper surface of the optical adhesive is flush with the upper surface of the first substrate.

[0019] Optionally, electronic components are disposed on the first substrate.

[0020] Optionally, the electronic components include resistors, capacitors, and printed circuit boards, with the resistors and capacitors electrically connected via the printed circuit boards.

[0021] Secondly, embodiments of this application provide an electronic device, including the laser semiconductor chip packaging structure of the first aspect.

[0022] Thirdly, embodiments of this application provide a laser semiconductor chip packaging method, including:

[0023] AlN green ceramic sheet is used for casting to obtain a first substrate green ceramic sheet and a second substrate green ceramic sheet, and through holes are formed on the first substrate green ceramic sheet.

[0024] A ceramic substrate is obtained by pressing and sintering a first substrate green ceramic sheet and a second substrate green ceramic sheet together; the ceramic substrate includes a first substrate formed of a first substrate green ceramic sheet and a second substrate formed of a second substrate green ceramic sheet.

[0025] A conductive pad and a laser semiconductor chip are mounted in the through-hole of the first substrate and on the second substrate.

[0026] A wire bonding technique is used to form a lead between the conductive pad and the laser semiconductor chip, and the height of both the laser semiconductor chip and the lead does not exceed the upper surface of the first substrate.

[0027] Optical adhesive is filled into the through-holes of the first substrate.

[0028] Optionally, the step of mounting the conductive pad and the laser semiconductor chip in the through-hole of the first substrate and on the second substrate includes: forming an adhesive pad in the through-hole of the first substrate and on the second substrate, and bonding the laser semiconductor chip to the adhesive pad with conductive silver paste.

[0029] Optionally, the method further includes: casting AlN green ceramic sheets to obtain a third substrate green ceramic sheet; and the step of pressurizing and sintering the first substrate green ceramic sheet and the second substrate green ceramic sheet includes pressurizing and sintering the first substrate green ceramic sheet, the second substrate green ceramic sheet, and the third substrate green ceramic sheet; and forming through holes in the second substrate green ceramic sheet. The ceramic substrate further includes: a third substrate formed by pressurizing and sintering the third substrate green ceramic sheet. The method further includes: mounting a reflector in the through holes of the second substrate and on the third substrate.

[0030] Optionally, the method further includes: printing screen printing and solder paste on a first substrate, and surface mounting resistors, capacitors and devices using an SMT pick and place machine.

[0031] Optionally, the method further includes reflow soldering the resistors, capacitors, devices, and the first substrate.

[0032] Compared with the prior art, this application has the following advantages:

[0033] The packaging structure, packaging method, and electronic device provided in this application embodiment utilize the space formed in the through-hole of the first substrate to accommodate the laser semiconductor chip and the lead wire. Since the highest point of the lead wire is still lower than the upper surface of the substrate after wire bonding, it does not affect screen printing, component mounting, and reflow soldering. Therefore, wire bonding can be performed first and then reflow soldering can be performed, thereby avoiding the influence of flux residue after reflow soldering on the wire bonding process.

[0034] Furthermore, by utilizing the space formed in the through-hole of the first substrate to pot optical adhesive, the metal or plastic shell as described in the prior art is not required, thus avoiding new reliability issues such as delamination and cracking between the shell and the substrate. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the appearance of a laser semiconductor chip packaging structure provided in an embodiment of this application;

[0037] Figure 2 An exploded view of a laser semiconductor chip packaging structure provided in this application embodiment;

[0038] Figure 3 This is a cross-sectional schematic diagram of a laser semiconductor chip packaging structure provided in an embodiment of this application;

[0039] Figure 4 This is a schematic flowchart of a laser semiconductor chip packaging method provided in an embodiment of this application.

[0040] Explanation of reference numerals in the attached figures:

[0041] 1-First substrate, 2-Second substrate, 3-Third substrate, 4-Conducting pad, 4'-Adhesive pad, 5-Conductive silver paste, 6-Laser semiconductor chip, 7-Lead, 8-Resistor, 9-Capacitor, 10-Device, 11-Reflective element, 12-Optical adhesive. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only some embodiments of this application, not all embodiments. The components of the embodiments of this application described in the accompanying drawings can generally be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0044] In the description of this application, it should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. The term "connection" should be interpreted broadly, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0045] Existing semiconductor lasers and semiconductor chips all require wire bonding to connect to the outside world for electrical and signal connections. In addition, solder paste needs to be screen-printed on the PCB. The solder paste contains flux or soldering agent. During the reflow soldering process, there will be volatilization and residue of flux or soldering agent, which will cause contamination of the wire bonding area, resulting in a high wire bonding failure rate and poor reliability.

[0046] Common solutions for protecting laser semiconductor chips typically involve using metal or plastic casings and encapsulating them with optical adhesive. However, this casing reduces the reliability of the structure.

[0047] To overcome the above problems, please refer to Figures 1 to 3 , Figure 1 This is a schematic diagram of the appearance of a laser semiconductor chip packaging structure provided in an embodiment of this application. Figure 2 This is an exploded view of the structure. Figure 3 This is a cross-sectional schematic diagram of the structure. This application provides a laser semiconductor chip packaging structure, including a substrate and an optical adhesive 12; the substrate includes a first substrate 1 and a second substrate 2, which are stacked from top to bottom.

[0048] The first substrate 1 has through holes; a laser semiconductor chip 6, a lead wire 7, and a conductive pad 4 are disposed in the through holes of the first substrate 1 and on the second substrate 2. The laser semiconductor chip 6 is connected to the conductive pad 4 through the lead wire 7. The height of the laser semiconductor chip 6 and the lead wire 7 does not exceed the upper surface of the first substrate 1; the through holes of the first substrate 1 are filled with optical adhesive 12. The lead wire can also be called a bonding wire or a lead wire.

[0049] In this embodiment, the space formed in the through-hole of the first substrate is used to accommodate the laser semiconductor chip and the lead wire. Since the highest point of the lead wire is still lower than the upper surface of the substrate after wire bonding, it does not affect screen printing, component mounting and reflow soldering. Therefore, wire bonding can be performed first and then reflow soldering can be performed, thereby avoiding the influence of flux residue after reflow soldering on the wire bonding process.

[0050] Furthermore, the embodiments of this application utilize the space formed in the through-hole of the first substrate to encapsulate optical adhesive, eliminating the need for metal or plastic shells as described in the prior art, thus avoiding new reliability issues such as delamination and cracking between the shell and the substrate.

[0051] Metals or polymers can be used as the substrate material. AlN can also be used as the substrate material. Correspondingly, embodiments of this application provide a laser semiconductor chip packaging method, such as... Figure 4 This includes the following steps:

[0052] S1, using AlN green ceramic sheet casting to obtain a first substrate green ceramic sheet and a second substrate green ceramic sheet, and forming a through hole on the first substrate green ceramic sheet (for example, forming a punched hole as the through hole by punching the first substrate green ceramic sheet).

[0053] S2, the first substrate green ceramic sheet and the second substrate green ceramic sheet are sintered under pressure to obtain a ceramic substrate; the ceramic substrate includes a first substrate 1 formed by the first substrate green ceramic sheet and a second substrate 2 formed by the second substrate green ceramic sheet.

[0054] S3, a conductive pad 4 and a laser semiconductor chip 6 are mounted in the through hole of the first substrate 1 and on the second substrate 2.

[0055] S4, a lead 7 is formed between the conductive pad 4 and the laser semiconductor chip 6 by wire bonding technology. The height of both the laser semiconductor chip 6 and the lead 7 does not exceed the upper surface of the first substrate 1.

[0056] S5, optical adhesive 12 is filled into the through hole of the first substrate 1.

[0057] When mounting the laser semiconductor chip 6 on the second substrate 2, in order to achieve functions such as electrical connection and heat conduction, or to ensure the reliability and stability of the mounting, such as... Figure 2 The enlarged view shows that bonding pads 4' can be provided on the second substrate 2, and the laser semiconductor chip 6 is connected to the bonding pads 4'. This process can be set in step S3: bonding pads 4' are made in the through holes of the first substrate 1 and on the second substrate 2, and the laser semiconductor chip 6 is bonded to the bonding pads 4' using conductive silver paste.

[0058] To ensure the reliability and stability of the laser semiconductor chip 6 installation, such as Figure 3 Furthermore, conductive silver paste 5 can be added, and the laser semiconductor chip 6 is connected to the bonding pad 4' through the conductive silver paste 5. The conductive silver paste 5 is on the connection surface between the laser semiconductor chip 6 and the bonding pad 4'.

[0059] Multiple laser semiconductor chips 6 can be installed to achieve more functions or higher power, such as... Figure 2Each of the laser semiconductor chip 6, lead wire 7, conductive pad 4, and bonding pad 4' can be set in two groups, arranged symmetrically on an axis. This symmetrical arrangement not only makes the design and process clearer but also improves the harmony and aesthetics of the workpiece appearance.

[0060] For symmetrically arranged laser semiconductor chips 6, leads 7, conductive pads 4, and bonding pads 4', when connecting them electrically, try to avoid affecting the optical path. Two sets of laser semiconductor chips 6, leads 7, and conductive pads 4 can be arranged sequentially from the inside to the outside along the axis of symmetry. The projection of the leads on the substrate can be set to be perpendicular to the axis of symmetry. Alternatively, two sets of laser semiconductor chips 6, leads 7, and conductive pads 4 can be arranged in opposite directions along the light emission direction.

[0061] To ensure the accuracy of the reflector 11's position and installation, a through hole can be provided on the second substrate 2, and a third substrate 3 can be provided below the second substrate 2. The reflector 11 can be installed in the through hole of the second substrate 2 and on the third substrate 3. The reflector can be a reflective prism.

[0062] Therefore, the light output direction can be set to a horizontal direction parallel to the substrate surface, and then after being reflected by the reflector 11, it is emitted perpendicular to the substrate surface.

[0063] For the aforementioned third substrate, a third substrate green ceramic sheet can be obtained by casting AlN green ceramic sheets. Step S2 involves pressing and sintering the first substrate green ceramic sheet, the second substrate green ceramic sheet, and the third substrate green ceramic sheet to obtain a ceramic substrate. Before pressing and sintering the first substrate green ceramic sheet, the second substrate green ceramic sheet, and the third substrate green ceramic sheet, through holes are formed on the second substrate green ceramic sheet. For example, through holes are formed by punching or drilling the second substrate green ceramic sheet. Then, the first to third substrate green ceramic sheets are pressed and sintered to obtain a ceramic substrate, which includes the first substrate 1, the second substrate 2, and the third substrate 3 stacked from top to bottom.

[0064] The through-hole of the second substrate 2 can be the same size as or larger than the through-hole of the first substrate 1, and its position can be offset from that of the through-hole of the first substrate 1. Preferably, the through-hole of the second substrate 2 is smaller than the through-hole of the first substrate 1, that is, the orthographic projection of the through-hole of the second substrate 2 onto the upper surface of the first substrate 1 is within the orthographic projection range of the through-hole of the first substrate 1 onto the upper surface of the first substrate 1.

[0065] Therefore, step S6 can be added to mount the reflector 11 in the through-hole of the second substrate 2 and on the third substrate 3. Step S6 is set before step S5, for example between S2 and S3, and between S3 and S5, so that the filling of the optical adhesive 12 does not interfere with other parts, including the reflector 11.

[0066] The reflector 11 can be configured such that at least its upper surface is exposed and not covered by the optical adhesive; the upper surface of the reflector 11 is higher than the upper surface of the first substrate 1; and the upper surface of the optical adhesive 12 is flush with the first substrate 1. This ensures that the reflector 11 has sufficient height, thereby ensuring higher light utilization.

[0067] Regarding the aforementioned structure and method for mounting reflectors, the holes in the second substrate 2 can serve a positioning function for the reflectors, and the edges of the holes can engage the reflectors. When the bottom surface of the reflector is rectangular, the shape of the holes can also be rectangular, and they can be set to rectangles of equal size to engage the reflectors, leaving only a one-gap fit tolerance, with four edges engaged. Alternatively, two edges can be engaged only in the width direction or only in the length direction to fix the mounting position of the reflector in one direction; three edges can also be engaged to fix the mounting position of the reflector in two directions, leaving a larger gap at one edge for installation.

[0068] The two sets of laser semiconductor chips 6, leads 7, and conductive pads 4 are arranged in opposite directions along the light emission direction, i.e., from near the reflector 11 to far away from the reflector 11. This allows the projection of the leads onto the substrate to be parallel to the axis of symmetry. The intersection line between the reflective surface of the reflector 11 and the upper surface of the second substrate 2 can be set perpendicular to the axis of symmetry of the two sets of laser semiconductor chips 6, meaning the distance from the two sets of laser semiconductor chips to the reflective surface is the same.

[0069] Electronic components can be placed on the first substrate 1 after the laser semiconductor chip 6 and leads 7 are arranged. The electronic components may include resistors 8, capacitors 9, and printed circuit boards, and may also include other devices 10. Resistors 8 and capacitors 9 are electrically connected via printed circuit boards. Conductor pads 4 or adhesive pads 4' can be connected to the electronic components via printed circuit boards or another set of leads.

[0070] Therefore, step S7 can be set after step S4, where screen printing and solder paste are printed on the first substrate 1, and the resistor 8, capacitor 9 and device 10 can be surface mounted by an SMT pick and place machine after screen printing and solder paste printing.

[0071] After surface mounting, step S8 can be set to reflow solder the resistor 8, capacitor 9, device 10 and the first substrate 1.

[0072] Setting S7 and S8 after S4 can avoid the problem of interference with the lead wire process in the background technology. They can be set before or after S5.

[0073] If set after S5, since the chip and leads are already protected by optical adhesive, the impact of flux or solder paste volatilization and residue on the lead fabrication process can be better avoided. In this case, it may be necessary to set the optical adhesive filler to be larger than the required filler amount. If flux or solder paste volatilizes and remains on the optical adhesive, the surface optical adhesive can be removed, for example, by scraping off the optical adhesive above the upper surface of the first substrate.

[0074] If steps S7 and S8 are set before S5, step S6, which involves installing the reflector, can be set after S8 or before S7. Installing the reflector after S8 avoids displacement of the reflector in subsequent processes due to unstable installation. To ensure stable installation, adhesives such as conductive silver paste can be used to further reinforce the connection between the reflector and the substrate.

[0075] To avoid the impact of steps S7 and S8 on the wire bonding process, step S9 can be set after step S4 to cover the via area of ​​the first substrate with a cover plate, i.e., cover the wires and the chip. Then, steps S7 and S8 are performed, followed by step S10, where the cover plate is removed to expose the via area of ​​the first substrate. Then, step S5, the optical adhesive is applied.

[0076] This application also provides an electronic device, including a laser semiconductor chip packaging structure. For example, a lidar component, or a vehicle equipped with lidar.

[0077] In general, this application proposes a laser semiconductor chip packaging structure, packaging method, and electronic device. The laser semiconductor chip and leads are accommodated by utilizing the space formed in the through-hole of the first substrate. Since the highest point of the leads is still lower than the upper surface of the substrate after wire bonding, it does not affect screen printing, component mounting, and reflow soldering. Therefore, wire bonding can be performed first and then reflow soldering, thereby avoiding the influence of flux residue after reflow soldering on the wire bonding process and avoiding the instability of the shell structure.

[0078] The apparatus and system embodiments described above are merely illustrative. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement these embodiments without any creative effort.

[0079] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A laser semiconductor chip packaging structure, characterized in that, It includes a substrate and an optical adhesive (12); the substrate includes a first substrate (1) and a second substrate (2), which are stacked from top to bottom; The first substrate (1) has through holes; a laser semiconductor chip (6), a lead wire (7) and a conductor pad (4) are disposed in the through holes of the first substrate (1) and on the second substrate (2). The laser semiconductor chip (6) is connected through the lead wire (7) and the conductor pad (4). The height of the laser semiconductor chip (6) and the lead wire (7) does not exceed the upper surface of the first substrate (1). Optical adhesive (12) is filled in the through holes of the first substrate (1). The substrate further includes a third substrate (3), and the first substrate (1), the second substrate (2) and the third substrate (3) are stacked from top to bottom. The second substrate (2) has a through hole. A reflective element (11) is provided in the through hole of the second substrate (2) and on the third substrate (3). The orthographic projection of the through hole of the second substrate (2) onto the upper surface of the first substrate (1) is within the orthographic projection range of the through hole of the first substrate (1) onto the upper surface of the first substrate (1). The upper surface of the reflector (11) is higher than the upper surface of the first substrate (1), and the upper surface of the optical adhesive (12) is flush with the upper surface of the first substrate (1).

2. The packaging structure as described in claim 1, characterized in that, An adhesive pad (4') is provided in the through hole of the first substrate (1) and on the second substrate (2), and the laser semiconductor chip (6) is connected to the adhesive pad (4').

3. The packaging structure as described in claim 2, characterized in that, The packaging structure also includes conductive silver paste (5), through which the laser semiconductor chip (6) is connected to the bonding pad (4').

4. The packaging structure as described in claim 2, characterized in that, The laser semiconductor chip (6), the lead wire (7), the conductive pad (4) and the bonding pad (4') each include two sets, and the two sets of laser semiconductor chips (6), lead wires (7) and conductive pads (4) are arranged in an axially symmetrical manner.

5. The packaging structure as described in claim 4, characterized in that, The two sets of laser semiconductor chips (6), leads (7) and conductive pads (4) are arranged sequentially from the inside to the outside along the axis of symmetry.

6. The packaging structure as described in claim 1, characterized in that, An electronic component is disposed on the first substrate (1). The electronic component includes a resistor (8), a capacitor (9), and a printed circuit board. The resistor (8) and the capacitor (9) are electrically connected through the printed circuit board.

7. An electronic device, characterized in that, Includes the laser semiconductor chip packaging structure according to any one of claims 1-6.

8. A method for packaging a laser semiconductor chip, characterized in that, include: AlN green ceramic sheet is used for casting to obtain a first substrate green ceramic sheet and a second substrate green ceramic sheet, and through holes are formed on the first substrate green ceramic sheet; The first substrate green ceramic sheet and the second substrate green ceramic sheet are sintered under pressure to obtain a ceramic substrate; the ceramic substrate includes a first substrate (1) formed from the first substrate green ceramic sheet and a second substrate (2) formed from the second substrate green ceramic sheet. In the through-hole of the first substrate (1) and on the second substrate (2), a conductive pad (4) and a laser semiconductor chip (6) are mounted. A lead (7) is formed between the conductive pad (4) and the laser semiconductor chip (6) by wire bonding technology. The height of both the laser semiconductor chip (6) and the lead (7) does not exceed the upper surface of the first substrate (1). Optical adhesive (12) is filled into the through holes of the first substrate (1). The method further includes: casting AlN green ceramic sheet to obtain a third substrate green ceramic sheet; and forming through holes on the second substrate green ceramic sheet; The step of pressing and sintering the first substrate green ceramic sheet and the second substrate green ceramic sheet includes pressing and sintering the first substrate green ceramic sheet, the second substrate green ceramic sheet and the third substrate green ceramic sheet; the ceramic substrate also includes a third substrate (3) formed by pressing and sintering the third substrate green ceramic sheet; the first substrate (1), the second substrate (2) and the third substrate (3) are stacked from top to bottom; The method further includes: mounting a reflector (11) in a through hole in the second substrate (2) and on the third substrate (3). The orthographic projection of the through hole of the second substrate (2) onto the upper surface of the first substrate (1) is within the orthographic projection range of the through hole of the first substrate (1) onto the upper surface of the first substrate (1). The upper surface of the reflector (11) is higher than the upper surface of the first substrate (1), and the upper surface of the optical adhesive (12) is flush with the upper surface of the first substrate (1).

9. The method as described in claim 8, characterized in that, The step of mounting the conductive pad (4) and the laser semiconductor chip (6) in the through-hole of the first substrate (1) and on the second substrate (2) includes: In the through-hole of the first substrate (1) and on the second substrate (2), an adhesive pad (4') is made, and a laser semiconductor chip (6) is bonded to the adhesive pad (4') with conductive silver paste.

10. The method as described in claim 8, characterized in that, The method further includes: printing screen and solder paste on the first substrate (1), and surface mounting resistors (8), capacitors (9) and devices (10) by an SMT pick and place machine.

11. The method as described in claim 10, characterized in that, The method further includes reflow soldering the resistor (8), the capacitor (9), the device (10) and the first substrate (1).

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