JP7200183B2 - Circuit board, protective cover and method for manufacturing circuit board - Google Patents

Description

The present disclosure relates to circuit boards and methods of manufacturing the same.

Demand for millimeter wave circuits is increasing due to the demand for next-generation communication standards such as 5G (fifth generation mobile communication system), and the use of Chip on Board (COB) is spreading to reduce costs. COB is a technique of mounting a bare chip on a circuit board (see, for example, Patent Document 1).

There are many types and numbers of circuit components to be mounted on a circuit board, and mounting them on a single circuit board inevitably increases the size of the circuit board due to layout restrictions. Also, in order to maintain transmission characteristics in the millimeter wave band, the circuit board must be thin. That is, since the aspect ratio of the length of the circuit board in the longitudinal direction and the thickness of the board becomes large, there is a problem that the circuit board bends when the circuit board is fixed to the case.

Also, the bare chip is protected by attaching an insulating resin or a shield case after the completion of mounting the circuit parts, but the bare chip is exposed during the process of mounting the circuit parts. In the bare chip mounting process, it is necessary to heat the circuit board with a heater and to use a positioning plate for setting the circuit board on the mounting machine. In order to fix the circuit board to the positioning plate, screws must be attached and removed from the mounting surface. The problem is that there is a risk of dropping the screw on the mounting surface and destroying it when attaching and detaching the screw. Failure detection and repair of bare chips are difficult, and a method was needed to avoid this risk of destruction.

JP-A-8-88316

An object of the present disclosure is to avoid bending that occurs when a circuit board on which a bare chip is mounted is fixed to a case.

The circuit board of the present disclosure comprises:
A circuit board on which a plurality of bare chips are mounted,
The circuit board is a plate-shaped insulator,
Through-holes are provided in the outer edge and central portion of the mounting surface on which the plurality of bare chips are mounted, and the bare chips are fixed to the shield case through the through-holes.

The circuit board of the present disclosure comprises:
The aspect ratio of one side to the thickness of the circuit board is 25 or more, and the plurality of bare chips includes a filter with one side of 3 mm or more.

The protective cover of the present disclosure is
A take-out portion is provided for taking out the circuit board fixed with screws,
The extraction part includes a notch provided on the outer edge,
Spacers provided at both ends in the longitudinal direction,
The spacer makes the distance from the mounting surface of the circuit board to the rear surface of the protective cover shorter than the length of the screw, thereby providing a structure in which the screw does not enter.

The manufacturing method of the circuit board of the present disclosure includes:
Fix the circuit board to the positioning plate with screws,
mounting circuit components and wiring on the circuit board;
covering the circuit board on which the circuit components and wiring are mounted with a protective cover having an extraction part for taking out the screw;
removing a screw fixed to the circuit board from the take-out portion provided in advance on the protective cover;
Remove the protective cover and the positioning plate from the circuit board.

According to the present disclosure, the present disclosure can avoid bending that occurs when fixing a circuit board with a bare chip mounted thereon to a case.

1 shows an example of a circuit board according to the present disclosure; 1 shows an example of a jig according to the present disclosure; 1 shows an example of a method for manufacturing a circuit board according to the present disclosure; An example of the structure of a circuit board and a positioning plate is shown. An example of the process of fixing the circuit board to the positioning plate is shown. An example of a process of mounting circuit components on a circuit board is shown. An example of the process of removing a screw is shown. An example of a process of removing a protective cover is shown. An example of a process of removing a circuit board is shown.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below. These implementation examples are merely illustrative, and the present disclosure can be implemented in various modified and improved forms based on the knowledge of those skilled in the art. In addition, in this specification and the drawings, constituent elements having the same reference numerals are the same as each other.

FIG. 1 shows an example of the circuit board of the present disclosure. The circuit board 11 of the present disclosure includes a printed circuit board, which is a plate-like insulator provided with conductor wiring. A plurality of bare chips are mounted on the mounting surface 11A of the circuit board 11 . A bare chip includes circuit components 26 such as integrated circuits, semiconductor devices, resistors, capacitors, and wiring. In addition to through holes 23-1, 23-3, 23-4, and 23-6 for fixing the four corners of the circuit board 11, the circuit board 11 is provided with a through hole 23-8 in the central portion. In this embodiment, as shown in FIG. 1, circuit components are placed at arbitrary positions within the area surrounded by through holes 23-1, 23-3, 23-4, and 23-6 on the mounting surface 11A of the circuit board 11. 26 and wiring can be mounted. One side W11 in the longitudinal direction of the circuit board ₁₁ is 100 mm or more, and the thickness of the circuit board 11 is 4 mm or less. The aspect ratio of one side _W11 of the circuit board and the thickness of the board is 25 or more.

FIG. 2 shows an example of a jig used in the present disclosure. The present disclosure uses a protective cover 13 as a jig to prevent the screws from dropping and destroying the bare chip during the mounting process. The protective cover 13 is fixed to the positioning plate 12 with thumbscrews 33 . Then, the screws 25-1 to 25-9 for fixing the positioning plate 12 and the circuit board 11 are attached and detached from the take-out portions 35-1 to 35-9 opened in the protective cover 13. FIG.

By using the method according to the present disclosure, it is possible to avoid the risk of destruction even when mounting a bare chip having a side of 3 mm or more on the circuit board 11 . For example, it is possible to mount a thin film substrate of 16 mm on a side to be used as a filter. A plurality of these bare chips and thin film substrates are mounted on the mounting surface of the circuit board 11 .

Fixation by the screws 25-1 to 25-9 is performed on the entire mounting surface of the circuit board 11. FIG. For example, four screws 25-1, 25-3, 25-4, and 25-6 fix the four corners of the circuit board 11. FIG. Two screws 25-2 and 25-5 fix the ends of the circuit board 11 in the longitudinal direction and the center in the lateral direction. Also, one screw 25-8 fixes the center of the substrate 11. As shown in FIG.

In this disclosure, as an example of an embodiment, a case where the protective cover 13 is provided with nine take-out portions 35-1 to 35-9 for taking out nine screws 25-1 to 25-9 is shown. In the following embodiments, the nine screws 25-1 to 25-9 will be referred to as screw 25 when not distinguished, and the nine take-out portions 35-1 to 35-9 will be referred to as take-out portion 35 when not distinguished. . The same applies to through holes, screw holes, and the like described below.

FIG. 3 shows an example of a method for manufacturing a circuit board according to the present disclosure. A circuit board manufacturing method according to the present disclosure includes the following steps S101 to S105.
Step S101: Fix the circuit board 11 to the positioning plate 12 with screws 25 (FIGS. 4 and 5).
Step S102: Mount the circuit component 26 and wiring on the circuit board 11 (FIG. 6).
Step S103: Mount the protective cover 13 on the circuit board 11 (FIG. 2).
Step S104: Remove screw 25 (FIG. 7).
Step S105: Remove the protective cover 13 (FIGS. 8 and 9).
The present disclosure performs steps S103 to S106 after the mounting of the circuit component 26 on the circuit board 11 is completed. A detailed description will be given below.

(Step S101)
As shown in FIG. 4 , the circuit board 11 is provided with pinholes 22 and the positioning plate 12 is provided with guide pins 21 . In this step, the guide pins 21 are engaged with the pinholes 22 and the circuit board 11 is placed on the positioning plate 12 . Thereby, the position of the circuit board 11 on the positioning plate 12 is determined.

The circuit board 11 and the positioning plate 12 are flat. The circuit board 11 is provided with through holes 23 - 1 to 23 - 9 , and the positioning plate 12 is provided with screw holes 24 - 1 to 24 - 9 that engage with the screws 25 . In this step, the screws 25 are engaged with the screw holes 24-1 to 24-9. As a result, the circuit board 11 is fixed to the positioning plate 12 with the screws 25, as shown in FIG. In addition to the through holes 23-1, 23-3, 23-4, and 23-6 for fixing the four corners of the circuit board 11, by providing a through hole 23-8 in the central portion, the aspect ratio of the circuit board 11 is increased. Even if it increases, it is possible to prevent the circuit board 11 from bending when it is fixed to the shield case. Furthermore, when the size of the circuit board 11 increases, the through holes may be distributed over the entire circuit board 11 .

The through holes provided in the circuit board 11 are not limited to those for passing the screws 25 . For example, the circuit board 11 may be provided with pin holes or through holes other than the guide pins 21 .

(Step S102)
In this step, circuit components 26 such as integrated circuits, semiconductor devices, resistors, capacitors, etc. and wiring are mounted on the circuit board 11 shown in FIG. In this embodiment, as shown in FIG. 6, circuit components 26 and wiring can be mounted on all areas of the circuit board 11 . In particular, circuit components 26 and wiring can be mounted even near screws 25 . The wiring may be printed wiring or wiring by wire bonding.

(Step S103)
As shown in FIG. 2, screw holes 31 are provided at both ends of the positioning plate 12 in the longitudinal direction, and notches 32 are provided at both ends of the protective cover 13 in the longitudinal direction. In this step, the protective cover 13 is overlaid on the positioning plate 12 and the thumb screw 33 is engaged with the screw hole 31 .

Spacers 34 are provided at both ends of the protective cover 13 in the longitudinal direction so that the protective cover 13 does not come into contact with the circuit components 26 . Moreover, the protective cover 13 has a structure in which the screws 25 do not enter between the protective cover 13 and the circuit board 11 . For example, the distance from the mounting surface of the circuit board 11 to the rear surface of the protective cover 13 is 2 mm, which is shorter than the length L25 of the screw ₂₅ . The inner diameter of the take-out portion 35 is substantially the same as the head diameter φ _25H of the screw 25 . Therefore, the present disclosure can avoid the risk of breaking the bare chip by the screw 25 .

(Step S104)
As shown in FIG. 7, the protective cover 13 is provided with a take-out portion 35 for taking out the screw 25. As shown in FIG. The through hole 35 may be a notch provided in the outer edge of the protective cover 13 . In this step, all the screws 25 are taken out using the take-out part 35 .

(Step S105)
As shown in FIG. 8, the thumbscrew 33 is removed and the protective cover 13 is removed. Thereby, as shown in FIG. 9, the circuit board 11 can be removed.

As described above, according to the present disclosure, the screws 25 that fix the positioning plate 12 and the circuit board 11 can be attached and detached from the extraction portion 35 opened in the protective cover 13 . The protective cover 13 has a structure in which the screws 25 do not enter between the protective cover 13 and the circuit board 11 . Therefore, according to the present disclosure, the protection cover 13 can avoid the risk of breakage due to the screws 25 during the bare chip mounting process, thereby improving product quality and yield.

The present disclosure can be applied to the information and communications industry.

11: Circuit board 11A: Mounting surface 12: Positioning plate 13: Protective cover 21: Guide pin 22: Pinhole 23: Through hole 24: Screw hole 25: Screw 26: Circuit component 31: Screw hole 32: Notch 33: Thumbscrew 34: Spacer 35: Extraction part

Claims (1)

A circuit board (11) on which a plurality of bare chips are mounted,
The circuit board is a plate-shaped insulator,
The aspect ratio of one side of the circuit board to the thickness is 25 or more,
The plurality of bare chips includes a filter with a side of 3 mm or more,
A through hole (23) is provided in the outer edge and central portion of the mounting surface on which the conductor wiring on which the plurality of bare chips are mounted is provided,
The through hole (23-8) provided in the central part penetrates the screw (25) fixed to the positioning plate (12) used for heating,
characterized by being fixed to the shield case through the through hole,
circuit board.

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