WO2020221051A1 - Printed circuit board and manufacturing method therefor, and electronic device - Google Patents

Abstract

Provided are a printed circuit board and a manufacturing method therefor, and an electronic device. The printed circuit board comprises a first printed circuit board (101), wherein the first printed circuit board (101) comprises a first surface (301) and a second surface (302), with the direction of the first surface (301) being opposite to the direction of the second surface (302); and the first printed circuit board (101) is provided with a first groove (201), with an opening of the first groove (201) facing the first surface (301). A first bonding pad (401) is arranged on the first surface (301), and an electronic element (040) is mounted to the second surface (302). The printed circuit board further comprises a second printed circuit board (102), wherein the second printed circuit board (102) comprises a third surface (303) and a fourth surface (304), with the direction of the third surface (303) being opposite to the direction of the fourth surface (304). The third surface (303) is provided with a second bonding pad (402), and the position of the second bonding pad (402) corresponds to the position of the first bonding pad (401); and the third surface (303) and the fourth surface (304) are respectively mounted with electronic elements (040). The first printed circuit board (101) and the second printed circuit board (102) are soldered together by means of the first bonding pad (401) and the second bonding pad (402) to form a stacking structure. The printed circuit board is not prone to warping, has stronger resistance to stress deformation, and can prolong the service life of an electronic device.

Description

Printed circuit board and its manufacturing method and electronic equipment

This application claims the priority of a Chinese patent application filed with the State Intellectual Property Office of China with application number 201910351844.3, and a Chinese patent application with the title of “a printed circuit board and its manufacturing method and electronic equipment” on April 28, 2019 The priority of, the entire content of which is incorporated in this application by reference.

Technical field

This application relates to the field of electronic technology, and in particular to a printed circuit board and its manufacturing method and electronic equipment.

Background technique

In miniaturized electronic devices, due to the small size of the device, the available space inside the device is very limited. Electronic equipment usually contains screens, batteries, printed circuit boards, camera modules, vibration motors and other components in a limited space. Therefore, high requirements are placed on the effective use of electronic equipment space; in addition, as electronic equipment calculates With the continuous improvement of performance, there needs to be enough space inside the electronic equipment to accommodate a larger capacity battery to ensure battery life.

In order to save the internal space of electronic devices, some current electronic devices use double-layer printed circuit boards. Figure 1a is a schematic cross-sectional view of a current double-layer printed circuit board. Figure 1b is an exploded view of the current printed circuit board structure. As shown in Figures 1a and 1b, the double-layer printed circuit board includes a top printed circuit board 010, a bottom printed circuit board 020, and a frame printed circuit board 030. Among them, the top printed circuit board 010 and the bottom printed circuit board 020 are mounted with electronics. Component 040, the frame printed circuit board 030 is located between the top printed circuit board 010 and the bottom printed circuit board 020, the frame printed circuit board 030 is a hollow ring structure as shown in Figure 2, through the ring structure, the frame printed circuit board 030 can be aligned The top printed circuit board 010 and the bottom printed circuit board 020 play a supporting role, and the frame printed circuit board 030 is soldered to the top printed circuit board 010 and the bottom printed circuit board 020 respectively, so that the frame printed circuit board 030 also has a connection to the top printed circuit board 010 The role of the electrical connection device with the bottom printed circuit board 020.

Under the influence of welding, removal processing, heat, torsion and other factors, the printed circuit board will be stressed and deformed and warped. Because the frame printed circuit board 030 is a hollow structure, its resistance to stress deformation is relatively small, and it is likely to form greater warpage when subjected to stress. When the warpage of the frame printed circuit board 030 is high, the supporting effect of the frame printed circuit board 030 on the top printed circuit board 010 and the bottom printed circuit board 020 will be reduced, which may affect the frame printed circuit board 030 and the top printed circuit board 010 The reliability of soldering with the bottom printed circuit board 020 leads to open soldering and electrical connection failure.

Summary of the invention

The embodiment of the present invention provides a printed circuit board. The printed circuit board includes: a first printed circuit board, the first printed circuit board includes a first surface and a second surface, the first surface and the second surface have opposite directions; the first printed circuit board is provided with a first groove, The opening of the groove faces the first surface; the first surface is provided with a first pad; the second surface is equipped with electronic components; the second printed circuit board, the second printed circuit board includes a third surface and a fourth surface, the third surface The direction is opposite to the fourth surface; the third surface is provided with a second pad, and the second pad corresponds to the position of the first pad; the third surface and the fourth surface are respectively mounted with electronic components; the first printed circuit board and the second The printed circuit board is welded by the first pad and the second pad to form a stacked structure.

In the printed circuit board provided by the embodiment of the present invention, since the first printed circuit board has the first groove, it can be directly welded with the second printed circuit board to form a double-layer stacked structure, without using the frame printed circuit board as a support, and avoiding frame printing The circuit board warps. In the case of the first printed circuit board with the first groove, it still has a continuous and complete board surface structure. Compared with the frame printed circuit board with a hollow structure, it has a stronger ability to resist stress and deformation. It is used in processing and welding. It is not easy to produce large warpage when subjected to stress, so it is helpful to improve the reliability of soldering between the first printed circuit board and the second printed circuit board, make the solder joints stronger, and avoid the printed circuit caused by the solder joints. Consequences of failure of electrical connections between boards. Further, the service life of electronic equipment using the printed circuit board can be increased.

Wherein, the opposite direction of the first surface and the second surface can be understood as the first surface and the second surface are opposite. That is, the first printed circuit board includes a first surface and a second surface opposite to the first surface. The opposite direction of the third surface and the fourth surface can be understood as the third surface and the fourth surface are opposite. That is, the second printed circuit board includes a third surface and a fourth surface opposite to the third surface.

In an implementation manner, the printed circuit board further includes: a third printed circuit board, the third printed circuit board includes a fifth surface and a sixth surface, the fifth surface and the sixth surface have opposite directions; the third printed circuit board is provided There is a second groove, and the opening of the second groove faces the fifth surface; the fifth surface is provided with a third pad; and the sixth surface is equipped with electronic components. The fourth surface is provided with a fourth pad; the second printed circuit board and the third printed circuit board are welded by the fourth pad and the third pad to form a stacked structure. Wherein, the fifth surface and the sixth surface have opposite directions can be understood as the fifth surface and the sixth surface are opposite. That is, the third printed circuit board includes a fifth surface and a sixth surface opposite to the fifth surface.

As a result, the first printed circuit board, the second printed circuit board and the third printed circuit board can be welded to form a three-layer stack structure without using the frame printed circuit board as a support, avoiding warpage of the frame printed circuit board, and further Reduce the projection area of the printed circuit board.

In an implementation manner, the printed circuit board further includes: a fourth printed circuit board, the fourth printed circuit board includes a seventh surface and an eighth surface, the seventh surface and the eighth surface have opposite directions; the fourth printed circuit board is provided There is a third groove, the opening of the third groove faces the seventh surface; the seventh surface is provided with a fifth pad; the eighth surface is equipped with electronic components. The second surface is provided with a sixth pad; the first printed circuit board and the fourth printed circuit board are welded by the sixth pad and the fifth pad to form a stacked structure. Wherein, the direction of the seventh surface and the eighth surface are opposite, which can be understood as the seventh surface and the eighth surface are opposite. That is, the fourth printed circuit board includes a seventh surface and an eighth surface opposite to the seventh surface.

As a result, the first printed circuit board, the second printed circuit board and the fourth printed circuit board can be welded to form a three-layer stack structure without using the frame printed circuit board as a support, avoiding warpage of the frame printed circuit board, and further Reduce the projection area of the printed circuit board.

In one implementation, when the electronic component is mounted on the third surface, at least a part of the electronic component is located in the first groove. As a result, the electromagnetic interference generated by the electronic component can be suppressed, and at the same time, the electromagnetic interference from the outside hardly affects the electronic component inside the first groove, thereby improving the stability of the electronic component.

In one implementation, when the electronic component is mounted on the fifth surface, at least a part of the electronic component is located in the second groove. As a result, the electromagnetic interference generated by the electronic component can be suppressed, and at the same time, the electromagnetic interference from the outside hardly affects the electronic component inside the first groove, thereby improving the stability of the electronic component.

In one implementation, when the electronic component is mounted on the seventh surface, at least a part of the electronic component is located in the third groove. As a result, the electromagnetic interference generated by the electronic component can be suppressed, and at the same time, the electromagnetic interference from the outside hardly affects the electronic component inside the first groove, thereby improving the stability of the electronic component.

In one implementation, the first printed circuit board includes a metal coating, and the metal coating is disposed in the first groove to form a metal shielding layer for isolating electromagnetic interference. Therefore, the metal shielding layer can enhance the ability of the first groove to isolate electromagnetic interference, so that the electronic components in the first groove can be better protected from electromagnetic interference.

In one implementation, when the first groove includes the exposed pad section, the metal coating is disposed on the remaining area of the first groove except the pad section, so that the metal coating and the pad section together form a metal shielding layer .

The present invention also provides a manufacturing method of a printed circuit board, which includes: removing material on the first surface of the first printed circuit board to form a first groove; and mounting the first part on the second surface of the first printed circuit board Electronic components; mount the second part of the electronic components on the fourth surface of the second printed circuit board; mount the third part of the electronic components on the third surface of the second printed circuit board, and pass the first pad and the first surface on the first surface The second pads on the three surfaces solder the first printed circuit board and the second printed circuit board to form a stacked structure.

The printed circuit board produced by the method provided by the embodiment of the present invention has a double-layer stack structure. Compared with a frame printed circuit board with a hollow structure, it has stronger resistance to stress and deformation, and it is not easy to process and solder when subjected to stress. Produces large warpage, so it is helpful to improve the reliability of soldering between the first printed circuit board and the second printed circuit board, make the solder joints stronger, and avoid the electrical connection between the printed circuit boards due to the open soldering of the solder joints Consequences of failure. Further, the service life of electronic equipment using the printed circuit board can be increased.

In one implementation, the method further includes: performing material removal processing on the fifth surface of the third printed circuit board to form a second groove; and mounting a fourth part of electronic components on the sixth surface of the third printed circuit board; When mounting the second part of the electronic components on the fourth surface, the second printed circuit board and the third printed circuit board are soldered to form a stacked structure through the fourth pad on the fourth surface and the third pad on the fifth surface.

In an implementation, the method further includes: performing material removal processing on the seventh surface of the fourth printed circuit board to form a third groove; and mounting the fifth part of electronic components on the eighth surface of the fourth printed circuit board; When mounting the first part of the electronic components on the second surface, the first printed circuit board and the fourth printed circuit board are soldered to form a stacked structure through the sixth pad on the second surface and the fifth pad on the seventh surface.

Therefore, the printed circuit board produced by the method provided by the embodiment of the present invention has a three-layer or four-layer stack structure. Compared with a frame printed circuit board with a hollow structure, it has a stronger ability to resist stress and deformation. It is not easy to produce large warpage when subjected to stress, so it is helpful to improve the reliability of soldering between the first printed circuit board and the second printed circuit board, make the solder joints stronger, and avoid printing caused by solder joints. Consequences of failure of electrical connections between circuit boards. Further, the service life of electronic equipment using the printed circuit board can be increased.

The embodiment of the present invention also provides an electronic device. The electronic device includes at least one printed circuit board provided by the present invention.

The electronic device provided by the embodiment of the present invention uses the printed circuit board with a stacked structure provided by the present invention, which can save the projection area occupied by the printed circuit board in the electronic device, and enable the electronic device to plan a larger space and set a larger size. A battery with a capacity to improve the battery life of electronic equipment is also conducive to the miniaturization of electronic equipment. In addition, since the printed circuit board soldering reliability of the printed circuit board provided by the present invention is higher, when the electronic device encounters external forces such as drop, vibration, impact or changes in cold and heat, the printed circuit board is less likely to be damaged such as open soldering. The service life and reliability of the electronic equipment provided by the present invention are improved.

Description of the drawings

Figure 1a is a schematic cross-sectional view of a current double-layer printed circuit board;

Figure 1b is an exploded view of the current printed circuit board structure;

Figure 2a is an exploded view of the structure of a printed circuit board provided by an embodiment of the present invention;

2b is a schematic cross-sectional view of a printed circuit board provided by an embodiment of the present invention;

3a is a schematic diagram of the structure of the first surface of the first printed circuit board;

3b is a schematic diagram of the structure of the second surface of the first printed circuit board;

4a is a schematic diagram of the structure of the third surface of the second printed circuit board;

4b is a schematic diagram of the structure of the fourth surface of the second printed circuit board;

5 is a flowchart of a method for manufacturing a printed circuit board according to an embodiment of the present invention;

6a is an exploded view of another printed circuit board structure provided by an embodiment of the present invention;

6b is a schematic cross-sectional view of another printed circuit board provided by an embodiment of the present invention;

FIG. 7 is a flowchart of a method for manufacturing a printed circuit board according to an embodiment of the present invention;

Figure 8a is an exploded view of another printed circuit board structure provided by an embodiment of the present invention;

8b is a schematic cross-sectional view of another printed circuit board provided by an embodiment of the present invention;

9 is another schematic diagram of the structure of the second surface of the first printed circuit board provided by the embodiment of the present invention;

10a is an exploded view of another printed circuit board structure provided by an embodiment of the present invention;

10b is a schematic cross-sectional view of another printed circuit board provided by an embodiment of the present invention;

11 is a schematic structural diagram of another printed circuit board provided by an embodiment of the present invention;

12 is another schematic diagram of the structure of the third surface of the second printed circuit board provided by the embodiment of the present invention;

FIG. 13 is a schematic structural diagram of a first groove shown in an embodiment of the present invention;

FIG. 14 is a schematic structural diagram of an electronic device provided by an embodiment of the present invention.

Illustration description:

10-printed circuit board, 20-printed circuit board, 010-top printed circuit board, 020-bottom printed circuit board, 030-frame printed circuit board, 040-electronic components, 041-system chip, 042-dynamic random access memory , 043- power management unit, 044- flash memory chip, 045- radio frequency chip, 046- power amplifier, 101- first printed circuit board, 102- second printed circuit board, 103- third printed circuit board, 104- fourth Printed circuit board, 201-first groove, 202-first bottom surface, 203-second groove, 204-second bottom surface, 205-third groove, 206-third bottom surface, 301-first printing surface, 302-second printing surface, 303-third printing surface, 304-fourth printing surface, 305-fifth printing surface, 306-sixth printing surface, 307-seventh printing surface, 308-eighth printing surface, 309 -Metal coating, 401-first pad, 402-second pad, 403-third pad, 404-fourth pad, 405-fifth pad, 406-sixth pad, 407-welding Disk section, 501-shell, 502-battery, 503-camera, 504-earpiece, 505-headphone hole, 601-first flexible circuit board, 602-second flexible circuit board, 603-third flexible circuit board, 604 -Fourth flexible circuit board, 701-first interface, 702-second interface, 703-third interface, 704-fourth interface.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

Fig. 2a is an exploded view of the structure of a printed circuit board provided by an embodiment of the present invention. 2b is a schematic cross-sectional view of a printed circuit board provided by an embodiment of the present invention. As shown in FIGS. 2a and 2b, the printed circuit board includes a first printed circuit board 101 and a second printed circuit board 102. Among them, the first printed circuit board 101 includes a first surface 301 and a second surface 302, the first surface 301 and the second surface 302 are in opposite directions; the second printed circuit board 102 includes a third surface 303 and a fourth surface 304, the third The surface 303 and the fourth surface 304 have opposite directions.

The first printed circuit board 101 is provided with a first groove 201, the opening of the first groove 201 faces the first surface 301, so that the first groove 201 forms a closed first bottom surface 202 on the first printed circuit board 101; One surface 301 is provided with a first pad 401 outside the first groove 201; the second surface 302 is mounted with electronic components 040. The third surface 303 of the second printed circuit board 102 is provided with a second pad 402 corresponding to the position of the first pad 401; the third surface 303 and the fourth surface 304 are respectively mounted with electronic components 040. The first printed circuit board 101 and the second printed circuit board 102 are soldered through the first pad 401 and the second pad 402 to form a two-layer stack structure.

In one implementation, in order to ensure that the first printed circuit board 101 still has sufficient structural strength with the first groove 201, the thickness of the first printed circuit board 101 may be greater than the thickness of the second printed circuit board 102 Therefore, after the first printed circuit board 101 is formed with the first groove 201, the thickness from the bottom surface 202 to the second surface 302 can also reach the thickness of the second printed circuit board 102. The depth of the first groove 201 can accommodate the electronic component 040 mounted on the third surface 303. As shown in FIG. 2b, the third surface 303 is installed with a power management unit (PMU) 043 and an embedded multimedia card (eMMC) 044.

In an implementation manner, as shown in FIG. 2b, the electronic component 040 in the embodiment of the present invention may be, for example, a system chip (system on a chip, SoC) 041, a dynamic random access memory (for example, double data rate Synchronous dynamic random access memory (double data rate synchronous dynamic random access memory, DDR SDRAM) 042, power management unit 043, flash memory chip (flash memory, for example: embedded multimedia card 044, universal flash storage (UFS) ), etc.) 044, radio frequency (RF) 045, power amplifier (power amplifier) 046, etc. The electronic component 040 is electrically connected to the first printed circuit board 101 or the second printed circuit board 102 through a soldering process such as reflow soldering.

In an embodiment, the SoC may include one or more processing units. For example, the SoC may include an application processor (AP), a modem processor, a graphics processing unit (GPU), and an image signal. Processor (image signal processor, ISP), controller, video codec, digital signal processor (digital signal processor, DSP), baseband processor, and/or neural-network processing unit (NPU) Wait. Among them, the different processing units may be independent devices or integrated in one or more units.

In an implementation manner, when the electronic component 040 is mounted on the third surface 303, the electronic component 040 may be partially or completely located in the area of the third surface 303 in the first groove 201. Thus, the enclosed cavity formed by the first groove 201 and the third surface can isolate the electronic component 040 from the external environment, so that electromagnetic interference (EMI) generated by the electronic component 040 on the third surface 303 can be suppressed At the same time, electromagnetic interference EMI from the outside is also difficult to affect the electronic components 040 on the third surface 303.

3a and 3b are schematic diagrams of the structure of the first printed circuit board 101 provided by an embodiment of the present invention, wherein FIG. 3a is a schematic diagram of the structure of the first surface 301 of the first printed circuit board 101, and FIG. 3b is the first printed circuit board A schematic diagram of the structure of the second surface 302 of the 101.

As shown in FIG. 3a, the first surface 301 is provided with first pads 401 outside the first groove 201, and the first pads 401 are distributed around the first groove 201. Preferably, the first pads 401 are distributed around the first groove 201 on the edge of the first surface 301, so that the first groove 201 can have a larger volume and can form a larger closed cavity with the third surface 303. More electronic components 040 can be installed on the third surface 303 in the closed cavity, and the anti-electromagnetic interference EMI performance of the printed circuit board is improved. The specific position and number of the first pads 401 can be determined according to the circuit design of the first printed circuit board 101 and the number of electrical connections between the first printed circuit board 101 and the second printed circuit board 102 to ensure the first pads 401 The number is enough to carry all the electrical connections between the first printed circuit board 101 and the second printed circuit board 102.

As shown in Figure 3b, the second surface 302 is equipped with electronic components 040. The electronic components 040 are distributed on the second surface 302 according to the circuit design of the first printed circuit board 101, and are fixedly mounted on the second surface by soldering processes such as reflow soldering. 302 on.

In one implementation, the second surface 302 is also installed with a shielding cover, such as a metal shielding cover. The metal shielding cover is used to cover part or all of the electronic components 040 installed on the second surface 302, so as to prevent electromagnetic interference of the covered electronic components 040. Interference acts as a suppression. The metal shield can be made of a lightweight aluminum sheet, which reduces the overall weight of the printed circuit board.

In one implementation, the second surface 302 is also covered with an interface material, for example, the interface material may be a heat radiation layer, the heat radiation layer is, for example, a thermally conductive film made of graphene material, and the heat radiation layer may be attached to the electronic component 040 and the surface of the metal shield. When the electronic component 040 generates heat during operation, the heat can be conducted to the interface material, and the heat radiation effect of the interface material is used to conduct the heat to the shielding cover, and then dissipating it to the outside through the shielding cover, thereby reducing the temperature of the electronic component 040 and preventing The electronic component 040 is overheated and damaged, and it can also prevent the electronic component 040 such as SoC from being overheated from frequency reduction and improve the performance of the electronic component 040.

In an implementation manner, a heat pipe may also be provided on the shielding cover, and an interface material, such as a thermal interface material, is provided between the heat pipe and the shielding cover. In this way, the heat conducted to the shield can be conducted to the heat pipe through the interface material. The heat pipe can be further connected to a thermally conductive bracket, such as a metal thermally conductive bracket, so that the heat conducted to the heat pipe can be dissipated through the thermally conductive bracket. Among them, the heat-conducting bracket may be a middle frame. The display screen and the circuit board can be located on both sides of the middle frame. The middle frame can support the display.

4a and 4b are schematic structural diagrams of the second printed circuit board 102 provided by an embodiment of the present invention. In conjunction with FIG. 2b, FIG. 4a is a schematic structural diagram of the third surface 303 of the second printed circuit board 102, and FIG. Two schematic diagrams of the structure of the fourth surface 304 of the printed circuit board 102.

As shown in FIG. 4a, the third surface 303 is provided with a second pad 402, and the position of the second pad 402 on the third surface 303 corresponds to the position of the first pad 401 on the first printed circuit board 101. When the length and width of the first printed circuit board 101 are the same as the length and width of the second printed circuit board 102, if the first land 401 surrounds the first groove 201 and is distributed on the edge of the first surface 301, the second land 402 is also correspondingly arranged on the edge of the third surface 303, so that when the positions of the first pad 401 and the second pad 402 coincide, the first printed circuit board 101 and the second printed circuit board 102 are just stacked neatly. The area of the third surface 303 located inside the second pad 402 is also mounted with electronic components 040, which are fixedly mounted on the third surface 303 by soldering processes such as reflow soldering. When the first printed circuit board 101 and the second printed circuit board 102 are stacked, the electronic components 040 mounted on the third surface 303 are located in the closed cavity formed by the first groove 201 and the third surface 303, which can be very good. The electromagnetic interference protection. In one embodiment, the electronic components on the third surface 303 may be chips sensitive to electromagnetic interference, such as digital to analog converters (DAC), operational amplifiers (OPA), etc., to improve the signals of these chips. Processing quality.

As shown in Figure 4b, electronic components 040 are mounted on the fourth surface 304. The electronic components 040 are distributed on the fourth surface 304 according to the circuit design of the second printed circuit board 102, and are fixedly mounted on the fourth surface by soldering processes such as reflow soldering. 304 on.

In one implementation, the fourth surface 304 is further equipped with a metal shielding cover, which is used to cover part or all of the electronic components 040 installed on the fourth surface 304, thereby suppressing electromagnetic interference of the covered electronic components 040 effect. In one implementation, the metal shield can be made of a lightweight aluminum sheet, which reduces the overall weight of the printed circuit board.

In one implementation, the fourth surface 304 is also covered with an interface material. For example, the interface material may be a heat radiation layer, the heat radiation layer may be a thermally conductive film made of graphene material, and the heat radiation layer may be attached to the electronic component. 040 and the surface of the metal shield. When the electronic component 040 generates heat during operation, the heat can be conducted to the interface material, and the heat radiation effect of the graphene and other materials is used to conduct the heat to the shielding cover, and the heat is dissipated through the shielding cover, thereby reducing the temperature of the electronic component 040 and preventing The electronic component 040 is overheated and damaged, and it can also prevent the electronic component 040 such as SoC from being overheated from frequency reduction and improve the performance of the electronic component 040.

FIG. 5 is a flow chart of a manufacturing method of a printed circuit board provided by an embodiment of the present invention. The manufacturing method is used for manufacturing a double-layer stacked printed circuit board as shown in 2. As shown in Figure 5, the method may include the following production process:

The first printed circuit board 101:

In step S101, material removal processing, such as milling processing, is performed on the first surface 301 of the first printed circuit board 101 to form the first groove 201.

In step S102, the first part of electronic components 040 is mounted on the second surface 302 of the first printed circuit board 101 by surface mount technology SMT, and the first part of electronic components 040 is electrically connected to the first printed circuit board 101 through soldering processes such as reflow soldering .

The second printed circuit board 102:

Step S201, the second part of electronic components 040 is mounted on the fourth surface 304 of the second printed circuit board 102 by SMT, and the second part of electronic components 040 is formed with the second printed circuit board 102 through soldering processes such as reflow soldering Electrical connections.

In step S202, after step S102, the third part of electronic components 040 and the first printed circuit board 101 are mounted on the third surface 303 of the second printed circuit board 102 through the surface mount technology SMT in one mounting process, so that the third part The electronic component 040 is soldered to the second printed circuit board 102 to form an electrical connection, and the first printed circuit board 101 and the second printed circuit board 102 are soldered to form an electrical connection through the first pad 401 and the second pad 402.

It can be understood that, in the method for manufacturing a printed circuit board in the foregoing embodiment, S201 may be executed first, then S101 and S102 may be executed, and then S202 may be executed. It is also possible to perform S102, S201, and S101 first, and then perform S202. Wherein, step S202 may be executed last, and the order of execution of steps S101, S102, and S201 may not be specifically limited.

In the printed circuit board provided by the above embodiment, the first printed circuit board 101 can be directly welded with the second printed circuit board 102 to form a double-layer stack structure because it has the first groove 201, and the frame printed circuit board does not need to be used as a support. The frame printed circuit board warps. When the first printed circuit board 101 has the first groove 201, it still has a continuous and complete board surface structure. Compared with the frame printed circuit board with a hollow structure, it has a stronger ability to resist stress and deformation. It is not easy to produce large warpage when soldering is under stress, so it is helpful to improve the reliability of soldering between the first printed circuit board 101 and the second printed circuit board 102, make the solder joints firmer, and avoid the welding of the solder joints. The consequence of the failure of the electrical connection between printed circuit boards. Further, the service life of electronic equipment using the printed circuit board can be increased.

Fig. 6a is an exploded view of another printed circuit board structure provided by an embodiment of the present invention. Fig. 6b is a schematic cross-sectional view of another printed circuit board provided by an embodiment of the present invention. On the basis of the structure of the printed circuit board shown in FIGS. 2a and 2b, the printed circuit board shown in FIGS. 6a and 6b further includes: a third printed circuit board 103, and the third printed circuit board 103 includes a fifth surface 305 and The sixth surface 306, the fifth surface 305 and the sixth surface 306 have opposite directions; the third printed circuit board 103 is provided with a second groove 203, and the opening of the second groove 203 faces the fifth surface 305, so that the second groove 203 A closed second bottom surface 204 is formed on the third printed circuit board 103. The fifth surface 305 is provided with a third pad 403; the sixth surface 306 is provided with an electronic component 040. The fourth surface 304 of the second printed circuit board 102 is provided with a fourth pad 404; the second printed circuit board 102 and the third printed circuit board 103 are soldered by the fourth pad 404 and the third pad 403 to form a stacked structure.

In the stacked structure shown in FIGS. 6a and 6b, the third surface 303 of the second printed circuit board 102 and the first groove 201 of the first printed circuit board 101 form a sealed cavity, and the second printed circuit board 102 The four surfaces 304 and the second groove 203 of the third printed circuit board 103 form a sealed cavity. Therefore, the electronic components 040 installed on the third surface 303 and the fourth surface 304 can be located in the enclosed cavity. The electromagnetic interference EMI generated by these electronic components 040 can be suppressed, and at the same time, the electromagnetic interference EMI from the outside can hardly affect the enclosure. The electronic component 040 inside the cavity improves the stability of the electronic component 040.

FIG. 7 is a flowchart of a method for manufacturing a printed circuit board according to an embodiment of the present invention. The manufacturing method is used for manufacturing a three-layer stacked printed circuit board as shown in 6a and 6b. As shown in Figure 7, the method may include the following production process:

The first printed circuit board 101:

In step S301, material removal processing is performed on the first surface 301 of the first printed circuit board 101 to form a first groove 201.

Step S302, the first part of electronic components 040 is mounted on the second surface 302 of the first printed circuit board 101 by SMT, and the first part of electronic components 040 is electrically connected to the first printed circuit board 101 through soldering processes such as reflow soldering .

The third printed circuit board 103:

In step S401, material removal processing is performed on the fifth surface 305 of the third printed circuit board 103 to form a second groove 203.

Step S402, the fourth part of electronic components 040 is mounted on the sixth surface 306 of the third printed circuit board 103 by surface mount technology SMT, and the fourth part of electronic components 040 and the third printed circuit board 103 are formed by soldering processes such as reflow soldering Electrical connections.

The second printed circuit board 102:

Step S501, after step S402, mount the second part of electronic components 040 on the fourth surface 304 of the second printed circuit board 102 by surface mount technology SMT, and print the second part through the fourth pad 404 and the third pad 403 The circuit board 102 and the third printed circuit board 103 are welded to form a stack structure, and the second printed circuit board 102 and the third printed circuit board 103 are welded through the fourth pad 404 and the third pad 403 to form an electrical connection.

Step S502, after step S302, mount a second part of electronic components 040 on the third surface 303 of the second printed circuit board 102 by surface mount technology SMT, and print the second part through the second pad 402 and the first pad 401 The circuit board 102 and the first printed circuit board 101 are welded to form a stack structure, and the first printed circuit board 101 and the second printed circuit board 102 are welded to form an electrical connection through the first pad 401 and the second pad 402.

It can be understood that, in the method for manufacturing a printed circuit board in the foregoing embodiment, the order of steps S301, S302, S401, and S402 can be exchanged, and the order of steps S501 and S502 can be exchanged.

In the printed circuit board provided by the above embodiment, the first printed circuit board 101 has a first groove 201, and the third printed circuit board 103 has a second groove 203, so that the first printed circuit board 101, the second printed circuit board 102 and The third printed circuit board 103 can be directly welded to form a three-layer stack structure, without using the frame printed circuit board as a support, to avoid warping of the frame printed circuit board. When the first printed circuit board 101 and the third printed circuit board 103 have the first groove 201 and the second groove 203, respectively, they still have a continuous and complete board structure, which is compared with the frame printed circuit with a hollow structure. The board has a stronger ability to resist stress and deformation, and it is not easy to produce large warpage when subjected to stress during processing and welding. Therefore, it is helpful to improve the reliability of welding, make the solder joints stronger, and avoid the welding caused by the opening of the solder joints. The consequences of the failure of the electrical connection between the printed circuit boards, thereby increasing the service life of the electronic equipment using the printed circuit boards.

Fig. 8a is an exploded view of another printed circuit board structure provided by an embodiment of the present invention. Fig. 8b is a schematic cross-sectional view of another printed circuit board provided by an embodiment of the present invention. On the basis of the structure of the printed circuit board shown in FIGS. 2a and 2b, the printed circuit board shown in FIGS. 8a and 8b further includes a fourth printed circuit board 104, and the fourth printed circuit board 104 includes a seventh surface 307 and The eighth surface 308, the seventh surface 307 and the eighth surface 308 are in opposite directions; the fourth printed circuit board 104 is provided with a third groove 205, the opening of the third groove 205 faces the seventh surface 307, so that the third groove 205 A closed third bottom surface 206 is formed on the fourth printed circuit board 104; the seventh surface 307 is provided with a fifth pad 405; the eighth surface 308 is provided with electronic components 040. The second surface 302 of the first printed circuit board 101 is provided with a sixth pad 406; the first printed circuit board 101 and the fourth printed circuit board 104 are welded by the sixth pad 406 and the fifth pad 405 to form a stacked structure.

In the stacked structure shown in FIGS. 8a and 8b, the third surface 303 of the second printed circuit board 102 and the first groove 201 of the first printed circuit board 101 form a sealed cavity, and the first printed circuit board 101 The second surface 302 and the third groove 205 of the fourth printed circuit board 104 form a sealed cavity. Therefore, the electronic components 040 installed on the third surface 303 and the second surface 302 can all be located in the enclosed cavity, and the electromagnetic interference EMI generated by these electronic components 040 can be suppressed. At the same time, the electromagnetic interference EMI from the outside can hardly affect the enclosure. The electronic component 040 inside the cavity improves the stability of the electronic component 040.

FIG. 9 is a schematic diagram of another structure of the second surface 302 of the first printed circuit board 101 provided by an embodiment of the present invention. As shown in FIG. 9, the second surface 302 of the first printed circuit board 101 is further provided with a sixth pad 406 on the basis of the structure shown in FIG. 3b. The position of the sixth pad 406 is similar to that of the fifth pad 405. The location corresponds. The electronic component 040 is mounted on the area of the second surface 302 located inside the sixth pad 406, and the electronic component 040 is mounted on the second surface 302 by soldering such as reflow soldering.

In the printed circuit board provided by the above embodiment, the first printed circuit board 101 has a first groove 201, and the fourth printed circuit board 104 has a third groove 205, so that the first printed circuit board 101, the second printed circuit board 102 and The fourth printed circuit board 104 can be directly welded to form a three-layer stack structure, without using the frame printed circuit board as a support, so as to avoid warping of the frame printed circuit board. When the first printed circuit board 101 and the fourth printed circuit board 104 have the first groove 201 and the third groove 205, respectively, they still have a continuous and complete board surface structure, which is compared with a frame printed circuit with a hollow structure. The board has a stronger ability to resist stress and deformation, and it is not easy to produce large warpage when subjected to stress during processing and welding. Therefore, it is helpful to improve the reliability of welding, make the solder joints stronger, and avoid the welding caused by the opening of the solder joints. The consequences of the failure of the electrical connection between the printed circuit boards, thereby increasing the service life of the electronic equipment using the printed circuit boards.

Fig. 10a is an exploded view of another printed circuit board structure provided by an embodiment of the present invention. FIG. 10b is a schematic cross-sectional view of another printed circuit board provided by an embodiment of the present invention. The printed circuit board of the printed circuit board shown in FIGS. 10a and 10b, on the basis of the structure of the printed circuit board shown in FIGS. 8a and 8b, further includes: a third printed circuit board 103, and the third printed circuit board 103 includes a first The fifth surface 305 and the sixth surface 306, and the fifth surface 305 and the sixth surface 306 have opposite directions; the third printed circuit board 103 is provided with a second groove 203, the opening of the second groove 203 faces the fifth surface 305, so that the The two grooves 201 form a closed second bottom surface 204 on the third printed circuit board 103; the fifth surface 305 is provided with a third pad 403; the sixth surface 306 is provided with an electronic component 040. The fourth surface 304 of the second printed circuit board 102 is provided with a fourth pad 404; the second printed circuit board 102 and the third printed circuit board 103 are soldered by the fourth pad 404 and the third pad 403 to form a stacked structure.

In the stacked structure shown in FIGS. 10a and 10b, the third surface 303 of the second printed circuit board 102 and the first groove 201 of the first printed circuit board 101 form a sealed cavity, and the second printed circuit board 102 has a sealed cavity. The four surfaces 304 and the second groove 203 of the third printed circuit board 103 form a sealed cavity, and the second surface 302 of the first printed circuit board 101 and the third groove 205 of the fourth printed circuit board 104 form a sealed cavity. Therefore, the electronic components 040 mounted on the second surface 302, the third surface 303, and the fourth surface 304 can all be located in the enclosed cavity, and the electromagnetic interference EMI (full name: Electromagnetic Interference) generated by these electronic components 040 can be suppressed, and at the same time, Electromagnetic interference EMI from the outside is also difficult to affect the electronic components 040 inside the enclosed cavity, thereby improving the stability of the electronic components 040.

In the printed circuit board provided by the above embodiment, the first printed circuit board 101 has a first groove 201, the third printed circuit board 103 has a second groove 203, and the fourth printed circuit board 104 has a third groove 205, so that the The one printed circuit board 101, the second printed circuit board 102, the third printed circuit board 103 and the fourth printed circuit board 104 can be directly welded to form a four-layer stack structure, without the need to use the frame printed circuit board as a support, avoiding the frame printed circuit board Produce warpage. The first printed circuit board 101, the third printed circuit board 103, and the fourth printed circuit board 104 have the first groove 201, the second groove 203 and the third groove 205, respectively, and still have a continuous and complete Compared with the frame printed circuit board of the hollow structure, the board surface structure has stronger ability to resist stress and deformation, and it is not easy to produce large warpage when subjected to stress during processing and welding. Therefore, it is beneficial to improve the reliability of welding and make welding The points are firmer, and the consequences of electrical connection failure between printed circuit boards due to open soldering of the solder points are avoided, thereby increasing the service life of electronic devices using the printed circuit boards.

It should be supplemented that the above content shows embodiments of printed circuit boards with two-layer, three-layer, and four-layer stacking structures. These embodiments are only some of the embodiments for realizing the technical solution of the present invention, rather than all the embodiments. Those skilled in the art can also obtain other embodiments of the present invention under the concept and enlightenment of the above-mentioned embodiments, such as a five-layer stack structure or a multi-layer stack structure, and these embodiments do not exceed the protection scope of the present invention.

Fig. 11 is a schematic structural diagram of another printed circuit board provided by an embodiment of the present invention.

FIG. 12 is a schematic diagram of another structure of the third surface 303 of the second printed circuit board 102 provided by an embodiment of the present invention.

As shown in Figures 11 and 12, in one embodiment, the length and/or width of the second printed circuit board 102 is greater than the length and/or width of the first printed circuit board 101, so that when the first printed circuit board 101 and After the second printed circuit board 102 has a stacked structure, the area of the third surface 303 of the second printed circuit board 102 outside the second pad 402 can also be mounted with electronic components 040. The printed circuit board structure shown in FIG. 11 can be applied to electronic equipment with irregular (for example, circular) space inside the housing to make full use of the internal space of the electronic equipment, improve the integration of the electronic equipment, and help make the electronic equipment Miniaturize or leave a larger space to accommodate a larger capacity battery to extend the battery life of electronic devices.

FIG. 13 is a schematic structural diagram of the first groove 201 according to an embodiment of the present invention.

As shown in FIG. 13, in one embodiment, the inner wall of the first groove 201 of the first printed circuit board 101 is provided with a metal coating 309, and the metal coating 309 can be attached to the entire first recess by spraying, coating, etc. The inner wall of the groove 201 forms a metal shielding layer that can isolate electromagnetic interference. When the first groove 201 and the third surface 303 of the second printed circuit board 102 form a closed cavity, the metal shielding layer can enhance the ability of the closed cavity to isolate electromagnetic interference, so that the electronic components 040 in the closed cavity are better. The electromagnetic interference protection.

As further shown in FIG. 13, the first printed circuit board 101 is provided with many pads for mounting electronic components 040. The pads usually extend to a certain depth on the first printed circuit board 101. Therefore, when on the first printed circuit board When the first groove 201 is formed by processing the first groove 201, some of the pads will be located just at the contour edge of the first groove 201, so that an exposed metal pad section 407 is formed on the inner wall of the first groove 201. Then, when there is an exposed pad section 407 on the inner wall of the first groove 201, the metal coating 309 is provided on the inner wall except for the remaining area of the pad section 407, so that each pad section 407 is connected through the metal coating 309, so that The metal coating 309 and the pad cross section 407 together form a metal shielding layer.

It should be supplemented that the metal coating 309 shown in FIG. 13 can also be applied to the second groove 203 and the third groove 205 at the same time, so that the second groove 203 and the third groove 205 can also form a metal shield In order to enhance the ability to isolate electromagnetic interference, the specific structure of the metal coating 309 applied in the second groove 203 and the third groove 205 will not be repeated in the embodiment of the present invention.

In one implementation, the first pad 401, the second pad 402, the third pad 403, the fourth pad 404, the fifth pad 405, and the sixth pad 406 are all subjected to copper leakage treatment. When using solder balls, use reflow soldering directly. As a result, the welding gap can be reduced, the printed circuit boards are stacked tightly after welding, the sealing performance of the enclosed cavity is improved, and the enclosed cavity can better shield electromagnetic interference.

FIG. 14 is a schematic structural diagram of an electronic device provided by an embodiment of the present invention.

As shown in FIG. 14, the electronic device includes a casing 501, a battery 502, and the printed circuit board 10 provided in an embodiment of the present invention; wherein, the battery 502 and the printed circuit board 10 are arranged in the casing 501.

In one implementation, the battery 502 is provided with a first flexible circuit board 601, the printed circuit board 10 is provided with a first interface 701 corresponding to the first flexible circuit board 601, and the first flexible circuit board 601 and the first interface 701 Plugging makes the battery 502 and the printed circuit board 10 realize electrical connection, and supplies power to the electronic components 040 mounted on the printed circuit board 10.

Among them, the electronic device also includes a display screen (not shown in Figure 14).

In one implementation, the display screen can be mounted on the housing 501, the display screen is provided with a second flexible circuit board 602, the printed circuit board 10 is provided with a second interface 702 corresponding to the second flexible circuit board 602, and the second The flexible circuit board 602 is plugged into the second interface 702 to electrically connect the display screen and the printed circuit board 10. The display screen is used to display images, videos, etc. The display screen includes a display panel. The display panel can be a liquid crystal display (LCD), an organic light-emitting diode (OLED), and an active matrix organic light emitting diode. Polar body or active matrix organic light emitting diode (active-matrix organic light emitting diode, AMOLED), flexible light-emitting diode (flex light-emitting diode, FLED), Miniled, MicroLed, Micro-oLed, quantum dot light-emitting diode (quantum dot light emitting diodes, QLED) etc. In some embodiments, the electronic device may include 1 or N display screens, and N is a positive integer greater than 1.

Among them, the electronic device also includes a camera 503.

In one implementation, the camera 503 is provided on one side of the printed circuit board 10, the camera 503 is provided with a third flexible circuit board 603, and the printed circuit board 10 is provided with a third interface 703 corresponding to the third flexible circuit board 603. The third flexible circuit board 603 is plugged into the third interface 703, so that the camera 503 and the printed circuit board 10 are electrically connected. The camera 503 is used to capture still images or videos. The object generates an optical image through the lens and projects it to the photosensitive element. The photosensitive element can be a charge coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS). ) Phototransistor. The photosensitive element converts the light signal into an electrical signal, and then transmits the electrical signal to an image signal processor (ISP) to convert it into a digital image signal. The ISP outputs the digital image signal to a digital signal processor (digital signal processor, DSP) for processing. Both ISP and DSP are mounted on the printed circuit board 10. DSP converts digital image signals into standard RGB, YUV and other formats. In some embodiments, the electronic device may include 1 or N cameras 503, and N is a positive integer greater than 1.

Among them, the electronic device also includes a receiver 504. The earpiece 504 is soldered to the printed circuit board 10 through pads, and is electrically connected to the printed circuit board 10. The earpiece 504 is used to convert an audio electric signal into a sound signal. When the electronic device answers a call or voice message, it can receive the voice by bringing the earpiece 504 close to the human ear.

Among them, the electronic device also includes a headphone jack 505.

In one implementation, one end of the earphone hole 505 is located on the housing 501 for the user to insert earphones, and the other end is soldered to the printed circuit board 10 through a pad on the printed circuit board 10, and is implemented with the printed circuit board 10. Electrical connections. The earphone interface can be a USB interface, or a 3.5mm open mobile terminal platform (OMTP) standard interface, or a cellular telecommunications industry association of the USA (CTIA) standard interface.

Wherein, the electronic device is provided with the printed circuit board 10 provided by the embodiment of the present invention.

In an implementation manner, for example, the electronic device shown in FIG. 14 further includes another printed circuit board 20, the printed circuit board 10 is arranged on the top of the housing 501, the battery 502 is arranged in the middle of the housing 501, and the printed circuit board 20 Set at the bottom of the housing 501, the printed circuit board 10 and the printed circuit board 20 are provided with a fourth interface 704, and are electrically connected by plugging the fourth flexible circuit board 604 and the fourth interface 704.

Among them, the electronic device may be an electronic device with a circuit board, such as a mobile phone, a tablet, a display screen, a wearable device, and glasses.

The electronic device provided by the above embodiments uses the printed circuit board with a stacked structure provided by the present invention, which can save the projection area occupied by the printed circuit board in the electronic device, so that the electronic device can plan a larger space and set a larger capacity. The battery 502, in order to improve the battery life of the electronic device, is also conducive to the miniaturization of the electronic device. In addition, since the printed circuit board soldering reliability of the printed circuit board provided by the present invention is higher, when the electronic device encounters external forces such as drop, vibration, impact or changes in cold and heat, the printed circuit board is less likely to be damaged such as open soldering. The service life and reliability of the electronic equipment provided by the embodiments of the present invention are improved.

Claims (12)

1. A printed circuit board, characterized in that it comprises:

   A first printed circuit board, the first printed circuit board includes a first surface and a second surface, the first surface and the second surface have opposite directions; the first printed circuit board is provided with a first groove, The opening of the first groove faces the first surface; the first surface is provided with a first pad; the second surface is mounted with electronic components;

   A second printed circuit board, the second printed circuit board includes a third surface and a fourth surface, the third surface and the fourth surface have opposite directions; the third surface is provided with a second pad, the The second pad corresponds to the position of the first pad; the third surface and the fourth surface are respectively mounted with electronic components;

   The first printed circuit board and the second printed circuit board are soldered to form a stacked structure by the first pad and the second pad.
2. 4. The printed circuit board of claim 1, further comprising:

   A third printed circuit board, the third printed circuit board includes a fifth surface and a sixth surface, the fifth surface and the sixth surface have opposite directions; the third printed circuit board is provided with a second groove, The opening of the second groove faces the fifth surface; the fifth surface is provided with a third pad; the sixth surface is mounted with electronic components;

   The fourth surface is provided with a fourth pad; the second printed circuit board and the third printed circuit board are welded by the fourth pad and the third pad to form a stacked structure.
3. The printed circuit board according to claim 1 or 2, further comprising:

   A fourth printed circuit board, the fourth printed circuit board includes a seventh surface and an eighth surface, the seventh surface and the eighth surface have opposite directions; the fourth printed circuit board is provided with a third groove, The opening of the third groove faces the seventh surface; the seventh surface is provided with a fifth pad; the eighth surface is mounted with electronic components;

   The second surface is provided with a sixth pad; the first printed circuit board and the fourth printed circuit board are welded to form a stacked structure by the sixth pad and the fifth pad.
4. 5. The printed circuit board according to any one of claims 1 to 3, wherein when the electronic component is mounted on the third surface, at least a part of the electronic component is located in the first groove.
5. 3. The printed circuit board according to claim 2, wherein when the electronic component is mounted on the fifth surface, at least a part of the electronic component is located in the second groove.
6. 4. The printed circuit board of claim 3, wherein when the electronic component is mounted on the seventh surface, at least a part of the electronic component is located in the third groove.
7. The printed circuit board according to any one of claims 1-6, wherein the first printed circuit board comprises a metal coating, and the metal coating is disposed in the first groove to form Metal shield to isolate electromagnetic interference.
8. The printed circuit board according to claim 7, wherein when the first groove includes an exposed pad cross section, the metal coating is disposed on the first groove to remove the cross section of the pad In the remaining area, the metal coating and the cross section of the pad together form the metal shielding layer.
9. A manufacturing method of a printed circuit board, characterized in that it comprises:

   Performing material removal processing on the first surface of the first printed circuit board to form a first groove;

   Mounting a first part of electronic components on the second surface of the first printed circuit board;

   Mounting the second part of electronic components on the fourth surface of the second printed circuit board;

   A third part of electronic components is mounted on the third surface of the second printed circuit board, and the first printed circuit is connected to the first printed circuit board through the first pads on the first surface and the second pads on the third surface. The plate and the second printed circuit board are welded to form a stacked structure.
10. The method according to claim 9, further comprising:

    Perform material removal processing on the fifth surface of the third printed circuit board to form a second groove;

    Mounting a fourth part of electronic components on the sixth surface of the third printed circuit board;

    When mounting the second part of the electronic components on the fourth surface, the second printed circuit board and the second printed circuit board are connected to each other through the fourth pad on the fourth surface and the third pad on the fifth surface. The third printed circuit board is welded to form a stacked structure.
11. The method according to claim 9 or 10, further comprising:

    Performing material removal processing on the seventh surface of the fourth printed circuit board to form a third groove;

    Mounting a fifth part of electronic components on the eighth surface of the fourth printed circuit board;

    When mounting the first part of the electronic components on the second surface, the first printed circuit board and the first printed circuit board are connected to each other through the sixth pad located on the second surface and the fifth pad located on the seventh surface. Four printed circuit boards are welded to form a stacked structure.
12. An electronic device, characterized by comprising: at least one printed circuit board according to any one of claims 1-8.

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