CN217882285U

CN217882285U - Laser semiconductor chip packaging structure and electronic equipment

Info

Publication number: CN217882285U
Application number: CN202222392876.8U
Authority: CN
Inventors: 秦红波; 符照森; 周翼钒; 韦盛琴
Original assignee: Guangzhou Asensing Technology Co Ltd
Current assignee: Guangzhou Asensing Technology Co Ltd
Priority date: 2022-09-08
Filing date: 2022-09-08
Publication date: 2022-11-22
Anticipated expiration: 2032-09-08

Abstract

The embodiment of the application provides a laser semiconductor chip packaging structure and electronic equipment, and relates to the technical field of packaging processes. In the packaging structure, a first substrate is provided with a through hole; the height of the laser semiconductor chip and the height of the lead wire which are arranged in the through hole of the first substrate and on the second substrate do not exceed the upper surface of the first substrate; and optical cement is filled in the through hole of the first substrate. The laser semiconductor chip and the lead are accommodated in the space formed in the through hole of the first substrate, and the highest point of the lead is still lower than the upper surface of the substrate after lead bonding, so that screen printing, component mounting and reflow soldering are not influenced, lead bonding can be carried out firstly, and then reflow soldering can be carried out, so that the influence of flux residue on a lead bonding process after reflow soldering is avoided.

Description

Laser semiconductor chip packaging structure and electronic equipment

Technical Field

The application relates to the technical field of packaging processes, in particular to a laser semiconductor chip packaging structure and electronic equipment.

Background

With the application development of the high-power semiconductor laser, for example, the application in the field of automatic vehicle driving is continuously expanded, and the characteristics of complex operation under vehicle-mounted working conditions, long life cycle of vehicle-mounted products and the like are considered, so that higher requirements are provided for the packaging quality of laser semiconductor chips and modules.

The semiconductor laser and the semiconductor chip which are commonly used in the market at present need to be connected with the outside by the method of wire bonding for electrical and signal connection. In the production process, a Printed Circuit Board (PCB) or a substrate surface is required to be screen-Printed with solder paste, and then the mounted components of the required components are subjected to reflow soldering.

Screen printing requires that the PCB or substrate surface be flat, so wire bonding cannot be performed on the PCB or substrate surface prior to screen printing, and it is common practice to perform screen printing of solder paste, component mounting, and reflow soldering prior to wire bonding.

However, solder paste contains flux or soldering flux, and the flux or soldering flux volatilizes and remains during reflow soldering, which causes contamination of a wire bonding area, resulting in a high wire bonding defect rate and poor reliability.

In addition, in terms of structure, the conventional solutions in the market at present usually adopt a metal or plastic shell for protecting the laser semiconductor chip and encapsulate optical glue to protect the laser semiconductor chip. On the one hand, this results in additional packaging processes, which leads to increased production costs; on the other hand, due to the difference of material properties, new reliability problems such as delamination and cracking are often generated between the metal or plastic shell and the substrate under working conditions such as thermal shock, thermal cycling and random vibration.

Therefore, how to reliably package the laser semiconductor chip is a technical problem to be solved.

SUMMERY OF THE UTILITY MODEL

The present application aims to provide a laser semiconductor chip packaging structure and an electronic device, so as to solve the technical problem of how to reliably package a laser semiconductor chip in the prior art.

In order to achieve the above purpose, the embodiments of the present application adopt the following technical solutions.

In a first aspect, an embodiment of the present application provides a laser semiconductor chip package structure, including a substrate and an optical cement; the substrate comprises a first substrate and a second substrate, and the first substrate and the second substrate are stacked from top to bottom.

The first substrate is provided with a through hole; the laser semiconductor chip is connected with the conduction band bonding pad through the lead, and the heights of the laser semiconductor chip and the lead do not exceed the upper surface of the first substrate; and optical cement is filled in the through hole of the first substrate.

Optionally, an adhesive pad is further provided in the through hole of the first substrate and on the second substrate, and the laser semiconductor chip is connected to the adhesive pad.

Optionally, the package structure further includes a conductive silver paste, and the laser semiconductor chip is connected to the bonding pad through the conductive silver paste.

Optionally, the laser semiconductor chip, the leads, the conduction band pads and the bonding pads each include two groups, and the two groups are arranged in axial symmetry.

Optionally, the two groups of laser semiconductor chips, the leads and the conduction band pads are arranged in sequence from inside to outside of the symmetry axis.

Optionally, the substrate further comprises a third substrate, the first substrate, the second substrate and the third substrate are stacked from top to bottom, and the second substrate is provided with a through hole; a light reflecting member is provided in the through hole of the second substrate and on the third substrate.

Optionally, an orthographic projection of the first substrate upper surface of the through hole of the second substrate is within an orthographic projection range of the first substrate upper surface of the through hole of the first substrate.

Optionally, the upper surface of the light reflecting member is higher than the upper surface of the first substrate, and the upper surface of the optical cement is flush with the upper surface of the first substrate.

Optionally, an electronic component is disposed on the first substrate.

Optionally, the electronic component comprises a resistor, a capacitor and a printing member, the resistor and the capacitor being electrically connected through the printing member.

In a second aspect, an embodiment of the present application provides an electronic device, including the laser semiconductor chip package structure of the first aspect.

In a third aspect, an embodiment of the present application provides a laser semiconductor chip packaging method, including:

carrying out tape casting on the AlN green ceramic chip to obtain a first substrate green ceramic chip and a second substrate green ceramic chip, and arranging a through hole on the first substrate green ceramic chip;

the green ceramic chips of the first substrate and the green ceramic chips of the second substrate are sintered under pressure to obtain a ceramic substrate; the ceramic substrate comprises a first substrate formed by a first substrate green ceramic chip and a second substrate formed by a second substrate green ceramic chip;

mounting a conduction band pad and a laser semiconductor chip in the through hole of the first substrate and on the second substrate;

forming a lead between the conduction band bonding pad and the laser semiconductor chip by a lead bonding technology, wherein the heights of the laser semiconductor chip and the lead do not exceed the upper surface of the first substrate;

and filling optical cement in the through hole of the first substrate.

Alternatively, the step of mounting the conduction band pad and the laser semiconductor chip in the through hole of the first substrate and on the second substrate includes: and manufacturing bonding pads in the through holes of the first substrate and on the second substrate, and bonding the laser semiconductor chip to the bonding pads by using conductive silver adhesive.

Optionally, the method further comprises: casting the AlN green ceramic chip to obtain a third substrate green ceramic chip, and sintering the first substrate green ceramic chip and the second substrate green ceramic chip under pressure; and arranging through holes on the second substrate green ceramic sheet. The ceramic substrate further includes: and a third substrate formed by pressing and sintering the third substrate green ceramic chip. The method further comprises the following steps: and mounting a light reflecting member in the through hole of the second substrate and on the third substrate.

Optionally, the method further comprises: printing silk screen and soldering paste on the first substrate, and carrying out surface mounting on the resistor, the capacitor and the device by an SMT chip mounter.

Optionally, the method further comprises: and performing reflow soldering on the resistor, the capacitor, the device and the first substrate.

Compared with the prior art, the method has the following beneficial effects:

the packaging structure and the electronic equipment provided by the embodiment of the application contain the laser semiconductor chip and the lead by virtue of the space formed in the through hole of the first substrate, and the highest point of the lead is still lower than the upper surface of the substrate after lead bonding, so that screen printing, component mounting and reflow soldering are not influenced, and reflow soldering can be carried out after lead bonding, and therefore the influence of flux residue on a lead bonding process after reflow soldering is avoided.

In addition, by means of the space formed in the through hole of the first substrate, optical glue is encapsulated, a metal or plastic shell in the background technology is not needed, and the problems of delamination, cracking and the like between the shell and the substrate are solved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

Fig. 1 is an external view of a laser semiconductor chip package structure according to an embodiment of the present disclosure;

fig. 2 is an exploded view of a laser semiconductor chip package according to an embodiment of the present disclosure;

fig. 3 is a schematic cross-sectional view of a laser semiconductor chip package structure according to an embodiment of the present disclosure;

fig. 4 is a schematic flowchart of a laser semiconductor chip packaging method according to an embodiment of the present disclosure.

Description of reference numerals:

1-a first substrate, 2-a second substrate, 3-a third substrate, 4-a conduction band pad, 4' -a bonding pad, 5-conductive silver paste, 6-a laser semiconductor chip, 7-a lead, 8-a resistor, 9-a capacitor, 10-a device, 11-a reflector and 12-optical glue.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and the described embodiments are some embodiments, but not all embodiments, of the present application. The components of the embodiments of the present application, as generally described in the figures herein, may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present application, as presented in the figures, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application. The embodiments described below and the features of the embodiments can be combined with each other without conflict.

In the description of the present application, it is noted that relational terms such as first and second, and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The term "connected" is to be understood broadly, for example, as being fixedly connected, detachably connected, or integrally connected; may be directly connected or indirectly connected through an intermediate.

The existing semiconductor laser and semiconductor chip need to be connected with the outside by electric and signal connection through a lead bonding method, and the PCB needs to be printed with solder paste by silk screen printing, the solder paste contains soldering flux or soldering flux, and the soldering flux or soldering flux volatilizes and remains in the reflow soldering process, so that the lead bonding area is polluted, the lead bonding reject ratio is high, and the problem of poor reliability is easy to occur.

In a commonly used scheme, a metal or plastic shell is usually adopted to protect the laser semiconductor chip, and optical glue is filled in the shell to protect the laser semiconductor chip. Such a housing in turn reduces the reliability of the structure.

In order to overcome the above problems, referring to fig. 1 to 3, fig. 1 is an external view of a laser semiconductor chip package structure provided in an embodiment of the present application, fig. 2 is an exploded view of the structure, fig. 3 is a cross-sectional view of the structure, and the embodiment of the present application provides a laser semiconductor chip package structure including a substrate and an optical cement 12; the substrate comprises a first substrate 1 and a second substrate 2, wherein the first substrate 1 and the second substrate 2 are stacked from top to bottom.

The first substrate 1 has a through hole; a laser semiconductor chip 6, a lead 7 and a conduction band pad 4 are arranged in the through hole of the first substrate 1 and on the second substrate 2, the laser semiconductor chip 6 is connected with the conduction band pad 4 through the lead 7, and the heights of the laser semiconductor chip 6 and the lead 7 do not exceed the upper surface of the first substrate 1; the through hole of the first substrate 1 is filled with an optical paste 12. The leads may also be referred to as wires, bond wires.

The embodiment of the application holds the laser semiconductor chip and the lead by means of the space formed in the through hole of the first substrate, and the highest point of the lead is still lower than the upper surface of the substrate after lead bonding, so that screen printing, surface mounting of components and parts and reflow soldering are not influenced, and reflow soldering can be carried out after lead bonding, and therefore the influence of flux residue on a lead bonding process after reflow soldering is avoided.

In addition, the embodiment of the application encapsulates the optical glue by virtue of the space formed in the through hole of the first substrate, does not need a metal or plastic shell in the background technology, and avoids the new reliability problems of delamination, cracking and the like between the shell and the substrate.

A metal or polymer may be selected as a raw material of the substrate. Correspondingly, the embodiment of the present application provides a laser semiconductor chip packaging method, as shown in fig. 4, including the following steps:

s1, carrying out tape casting by using the AlN green ceramic chip to obtain a first substrate green ceramic chip and a second substrate green ceramic chip, and arranging a through hole on the first substrate green ceramic chip (for example, stamping the first substrate green ceramic chip to form a stamping hole as the through hole);

s2, pressurizing and sintering the first substrate green ceramic chip and the second substrate green ceramic chip to obtain a ceramic substrate; the ceramic substrate comprises a first substrate 1 formed by a first substrate green ceramic chip and a second substrate 2 formed by a second substrate green ceramic chip;

s3, mounting a conduction band pad 4 and a laser semiconductor chip 6 in the through hole of the first substrate 1 and on the second substrate 2;

s4, forming a lead 7 between the conduction band bonding pad 4 and the laser semiconductor chip 6 through a lead bonding technology, wherein the heights of the laser semiconductor chip 6 and the lead 7 do not exceed the upper surface of the first substrate 1;

and S5, filling the optical cement 12 in the through hole of the first substrate 1.

In mounting the laser semiconductor chip 6 on the second substrate 2, in order to realize functions such as electrical connection and thermal conduction, and reliability and stability of mounting, as shown in a partially enlarged view of fig. 2, an adhesive pad 4 'may be provided on the second substrate 2, and the laser semiconductor chip 6 may be connected to the adhesive pad 4'. This process may be set at step S3: 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 adhered to the adhesive pad 4' with a conductive silver paste.

For the reliability and stability of the laser semiconductor chip 6, as shown in fig. 3, a conductive silver paste 5 may be further provided, the laser semiconductor chip 6 is connected to the bonding pad 4 'through the conductive silver paste 5, and the conductive silver paste 5 is on the connection surface of the laser semiconductor chip 6 and the bonding pad 4'.

A plurality of laser semiconductor chips 6 can be mounted to realize more functions or higher power, and as shown in fig. 2, the laser semiconductor chips 6, the leads 7, the conduction band pads 4 and the bonding pads 4' can be arranged in two groups, and the two groups are arranged in axial symmetry. The axisymmetric arrangement not only can make the design and the process clear and definite, but also can improve the co-scheduling and the aesthetic feeling of the appearance of the workpiece.

For the laser semiconductor chips 6, the leads 7, the conduction band pads 4 and the bonding pads 4' which are symmetrically arranged, when the laser semiconductor chips, the leads 7, the conduction band pads 4 and the bonding pads are led out and electrically connected, the influence on a light path is avoided as much as possible, two groups of laser semiconductor chips 6, the leads 7 and the conduction band pads 4 can be arranged in sequence from inside to outside of a symmetry axis, and the projection of the leads on a substrate can be perpendicular to the symmetry axis; it is also possible to provide that two sets of laser semiconductor chips 6, leads 7, and conduction band pads 4 are arranged in the opposite direction to the light-emitting direction.

In order to adjust the position and mounting accuracy of the reflectors 11, the second substrate 2 may be provided with through holes, the third substrate 3 may be provided below the second substrate 2, and the reflectors 11 may be provided in the through holes of the second substrate 2 and on the third substrate 3. The light reflecting member may be a light reflecting prism.

Therefore, the light emitting direction can be set to be a horizontal direction parallel to the substrate surface, and then the light enters the light reflecting member 11 to be reflected, and then the light is emitted perpendicularly to the substrate surface.

For the third substrate, the third substrate green ceramic chip can be obtained by casting AlN green ceramic chip, and the step S2 is to press-sinter the first substrate green ceramic chip, the second substrate green ceramic chip and the second substrate green ceramic chip to obtain the ceramic substrate. Before the first substrate green ceramic chip, the second substrate green ceramic chip and the third substrate green ceramic chip are subjected to pressure sintering, a through hole is formed in the second substrate green ceramic chip, for example, a stamping hole is formed in the second substrate green ceramic chip through stamping to serve as the through hole, or the through hole is formed in a drilling mode; and then, carrying out pressure sintering on the green ceramic chips of the first to the third substrates to obtain the ceramic substrate, wherein the ceramic substrate comprises a first substrate 1, a second substrate 2 and a third substrate 3 which are stacked from top to bottom.

The through hole of the second substrate 2 may be the same size as the through hole of the first substrate 1, may be larger than the through hole of the first substrate 1, or may be displaced from 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, i.e. the orthographic projection of the upper surface of the first substrate 1 of the through hole of the second substrate 2 is within the orthographic projection range of the upper surface of the first substrate of the through hole of the first substrate 1.

A step S6 of mounting the light reflectors 11 in the through holes of the second substrate 2 and on the third substrate 3 may thus be added. Step S6 is provided before step S5, for example between S2 and S3, between S3 and S5, so that the filling of the optical glue 12 does not interfere with other components including the light reflecting member 11.

At least the upper surface of the light reflecting member 11 may be exposed and not covered by the optical cement; the upper surface of the light reflecting piece 11 is higher than the upper surface of the first substrate 1; the upper surface of the optical cement 12 is flush with the first substrate 1. This ensures that the height of the reflector 11 is sufficient, thereby ensuring a higher light utilization rate.

With the above structure and method for mounting the light reflecting member, the hole of the second substrate 2 may have a function of positioning the light reflecting member, and the edge of the hole may clamp the light reflecting member. When the bottom surface of the light reflecting piece is rectangular, the shape of the hole can also be rectangular, the holes can be rectangular with the same size to clamp the light reflecting piece, only one clearance fit tolerance is left, and the four edges are matched. The two edges in only the width direction or only the length direction can be matched to fix the installation and the positioning of the light reflecting piece in one direction; three edges may be provided to cooperate to fix the reflector in two orientations, leaving a large gap at one edge for installation.

The two groups of laser semiconductor chips 6, the leads 7 and the conduction band bonding pads 4 are arranged along the opposite directions of the light emitting direction, namely the two groups of laser semiconductor chips 6, the leads 7 and the conduction band bonding pads 4 are arranged from being close to the reflector 11 to being far away from the reflector 11, namely the projection of the leads on the substrate can be parallel to the symmetry axis. The intersection line of the reflecting surface of the reflector 11 and the upper surface of the second substrate 2 may be perpendicular to the symmetry axes of the two groups of laser semiconductor chips 6, that is, the distances from the two groups of laser semiconductor chips to the reflecting surface are the same.

The electronic components may be provided on the first substrate 1 after the laser semiconductor chip 6 and the leads 7 are arranged. The electronic assembly may comprise a resistor 8, a capacitor 9 and a printing, and may further comprise other devices 10, the resistor 8 and the capacitor 9 being electrically connected by the printing. The tape pads 4 or the bond pads 4' may be connected to the electronic component by printing or another set of leads.

Step S7 may thus be provided after step S4, printing a screen and solder paste on the first substrate 1, and surface mounting the resistor 8, the capacitor 9, and the device 10 by an SMT pick and place machine after printing the screen and the solder paste.

After surface mounting, step S8 may be provided to perform reflow soldering on the resistor 8, the capacitor 9, the device 10 and the first substrate 1.

The S7 and S8 are set after S4, which can avoid the problem of interference to the wire process in the background art, and can be set before or after S5.

If the chip and the lead are arranged after S5, the influence of volatilization and residue of the soldering flux or the scaling powder on the lead process can be better avoided because the chip and the lead are protected by the optical cement. In this case, it may be necessary to set the filling amount of the optical paste to be larger than the required filling amount, and if the volatilization of the flux or soldering flux remains on the optical paste, the optical paste on the surface may be removed, for example, the optical paste above the upper surface of the first substrate may be scraped off.

If S7, S8 are set before S5, the step S6 of mounting the light reflecting member may be set after S8 or before S7. And the reflector is installed after S8, so that the problem that the reflector is displaced in the subsequent process due to instable installation of the reflector can be avoided. In order to ensure the stable installation of the reflector, the connection between the reflector and the substrate may be further reinforced by glue, such as conductive silver glue.

In order to avoid the influence of S7 and S8 on the wire bonding process, S9 may be further provided after S4, and the through hole region of the first substrate, i.e. the wires and the chip, may be covered by a cover plate. Then, S7 and S8 are performed, and then, S10 is performed, and the cover plate is removed to expose the through hole region of the first substrate. Then, the step S5 of filling the optical paste is performed.

The embodiment of the application also provides electronic equipment which comprises a laser semiconductor chip packaging structure. Such as a lidar component, or a vehicle with a lidar, etc.

Generally speaking, the application provides a laser semiconductor chip packaging structure, packaging method and electronic equipment, with the help of the space that forms in the first base plate through-hole, hold laser semiconductor chip and lead wire, because the lead wire peak is still less than the base plate upper surface behind the wire bonding, does not influence screen printing, pastes dress components and parts and reflow soldering, consequently can carry out the wire bonding earlier and carry out reflow soldering again to the influence of brazing flux residual to the wire bonding technology after having avoided reflow soldering, and avoided the unstable problem of shell structure.

The above-described embodiments of the apparatus and system are merely exemplary, and some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement without inventive effort.

The above description is only for the preferred embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application are also included in the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. The laser semiconductor chip packaging structure is characterized by comprising a substrate and optical cement (12); the substrate comprises a first substrate (1) and a second substrate (2), wherein the first substrate (1) and the second substrate (2) are stacked from top to bottom;

the first substrate (1) is provided with a through hole; a laser semiconductor chip (6), a lead (7) and a conduction band pad (4) are arranged in the through hole of the first substrate (1) and on the second substrate (2), the laser semiconductor chip (6) is connected with the conduction band pad (4) through the lead (7), and the heights of the laser semiconductor chip (6) and the lead (7) do not exceed the upper surface of the first substrate (1); and optical cement (12) is filled in the through hole of the first substrate (1).

2. The package structure according to claim 1, wherein an adhesive pad (4 ') is further provided in the through hole of the first substrate (1) and on the second substrate (2), the laser semiconductor chip (6) being connected to the adhesive pad (4').

3. The package structure according to claim 2, characterized in that the package structure further comprises a conductive silver paste (5), and the laser semiconductor chip (6) is connected to the bonding pad (4') through the conductive silver paste (5).

4. The package structure according to claim 2, wherein the laser semiconductor chip (6), the lead (7), the tape pad (4), and the adhesive pad (4') each comprise two groups, and the two groups of the laser semiconductor chip (6), the lead (7), and the tape pad (4) are arranged in axial symmetry.

5. The package structure according to claim 4, wherein the two groups of laser semiconductor chips (6), the leads (7) and the conduction band pads (4) are arranged in sequence from inside to outside from the symmetry axis.

6. The package structure according to claim 1, wherein the substrate further comprises a third substrate (3), the first substrate (1), the second substrate (2) and the third substrate (3) are stacked from top to bottom, and the second substrate (2) has a through hole; a light-reflecting member (11) is provided in the through hole of the second substrate (2) and on the third substrate (3).

7. The package structure according to claim 6, characterized in that an orthographic projection of the upper surface of the first substrate (1) of the through hole of the second substrate (2) is within an orthographic projection of the upper surface of the first substrate (1) of the through hole of the first substrate (1).

8. The package structure according to claim 6, wherein the upper surface of the light reflecting member (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 encapsulation structure according to claim 1, characterized in that an electronic component is arranged on the first substrate (1), the electronic component comprising a resistor (8), a capacitor (9) and a printing, the resistor (8) and the capacitor (9) being electrically connected by the printing.

10. An electronic device comprising the laser semiconductor chip package according to any one of claims 1 to 9.