WO2023123907A1

WO2023123907A1 - Manufacturing method for rigid-flex board, and circuit board

Info

Publication number: WO2023123907A1
Application number: PCT/CN2022/100046
Authority: WO
Inventors: 肖璐; 林宇超; 钟美娟; 朱光远; 张志远
Original assignee: 生益电子股份有限公司
Priority date: 2021-12-27
Filing date: 2022-06-21
Publication date: 2023-07-06
Also published as: CN114401594A

Abstract

A manufacturing method for a rigid-flex board, and a circuit board. In the present embodiment, the method comprises: applying a first covering film to a surface of a bending region of a flexible board layer; making an outline pattern, which is smaller than the first covering film and corresponds to the bending region; next, applying a protective adhesive tape to a surface of a specified bending region to protect the bending region; applying a second covering film to a first region of a rigid board layer; then, performing sequential board stacking and lamination, so that the flexible board layer and the rigid board layer are stacked in sequence to obtain a motherboard; and uncovering a first specified region of a bonding sheet of the flexible board layer and the rigid board layer of the motherboard, wherein the first specified region is located on an outer side of the bending region, and then removing the protective adhesive tape to obtain a rigid-flex board.

Description

Rigid-flex board manufacturing method and circuit board

This application claims priority to a Chinese patent application with a filing date of December 27, 2021 and application number 202111613639.3, the entire contents of which are incorporated herein by reference.

technical field

This application relates to the technical field of PCB (Printed Circuit Boards, printed circuit boards), for example, it relates to a manufacturing method of a soft-rigid combination board and a circuit board.

Background technique

Rigid-flex board is a combination of flexible circuit board and rigid circuit board through pressing and other processes to form a flexible circuit board (Flexible Printed Circuit Board, FPC) and a printed circuit board (Printed Circuit Boards, PCB) The circuit board with special characteristics; because the soft-rigid combination board has both a certain rigid area and a certain flexible area, and the flexible area can be bent, so it has great advantages in saving the internal space of the product, reducing the volume of the finished product and improving the performance of the product. Advantage.

In related technologies, the flying-tail type rigid-flex board is more commonly used in the rigid-flex board. However, due to the limitation of the process, the gold finger can only be made on the edge of the board, which limits the use of the gold finger. Location.

Contents of the invention

The present application provides a method for manufacturing a rigid-flex board and a circuit board, which can flexibly design the position of a gold finger in the board.

On the one hand, an embodiment of the present application provides a method for manufacturing a rigid-flex board, including:

Provide a soft board layer, a prepreg and a hard board layer; the soft board layer is provided with a bending area, and the bending area is provided with golden fingers, and the hard board layer is provided with a first area, and the first area is the In the area of the hard board layer that is not covered by the prepreg; paste the first covering film on the surface of the bending area; make the shape corresponding to the bending area, and the shape is smaller than the first covering film; A protective tape is pasted on the surface of the bending area, and the designated bending area is the bending area facing the copper foil layer with the outermost soft board layer; the second cover film is pasted on the first area; the boards are laminated and pressed in sequence, The soft board layer and the hard board layer are stacked in sequence to obtain a mother board; and the first designated area of the mother board is opened, and the protective tape is removed, and the first designated area is the Substrate and copper foil outside the flex area of the flex layer.

In an embodiment, the manufacturing method further includes: attaching reinforcement to a second designated area of the bending area, and the second designated area corresponds to the other side of the soft board layer corresponding to the golden finger.

In one embodiment, the protective tape is a single-sided tape, and the manufacturing method includes: attaching the adhesive side of the single-sided tape to the surface of the soft board layer in advance; and removing the single-sided tape The effective area of the single-sided adhesive tape is reserved, and the position of the effective area covers the shape groove corresponding to the bending area.

In one embodiment, the protective tape is a double-sided tape, and the manufacturing method includes: attaching the first adhesive surface of the double-sided tape to the soft board layer of the adhesive sheet in advance Or, the second adhesive surface of the double-sided tape is attached to the surface of the soft board layer facing the bonding sheet in advance; the viscosity of the first adhesive surface is greater than that of the first adhesive surface. The viscosity of the second adhesive surface; and removing the invalid area of the double-sided tape, retaining the effective area of the double-sided tape, the position of the effective area covers the shape groove corresponding to the bending area.

In one embodiment, the rigid-flex board includes a plurality of soft board layers, and the prepreg includes a first prepreg stacked between two soft board layers and a first prepreg stacked on the soft board layer. and the second prepreg between the hard board layers, the manufacturing method further includes: opening a window on the first prepreg and the second prepreg, and the size of the window opening area is larger than the size of the first covering film .

In an embodiment, the manufacturing method further includes: performing surface treatment on the golden finger.

In one embodiment, before pasting the first cover film on the surface of the bending area, it also includes: making the inner layer pattern of each layer of core boards; browning each layer of core boards; and following the preset stacking sequence After the flexible board layers are stacked, a pressing process is performed to obtain the rigid-flex board.

In one embodiment, after attaching the protective tape to the surface of the bending area, it further includes: providing copper foil; and sequentially laminating and pressing the plates, so that the prepreg and copper foil are sequentially stacked on the surface of the protective tape. Directly above.

In one embodiment, after the sequential stacking and pressing, so that the soft board layer and the hard board layer are sequentially stacked to obtain the motherboard, it also includes: making the outer layer pattern of the motherboard; and Carry out green oil treatment, surface treatment and shape treatment on the motherboard.

An embodiment of the present application provides a circuit board, which is manufactured according to the method for manufacturing a rigid-flex board as described above.

Description of drawings

Fig. 1 is a schematic flow chart of a manufacturing method of a rigid-flex board provided by an embodiment of the present application;

Fig. 2 is a schematic structural diagram of a soft board layer provided by an embodiment of the present application;

Fig. 3 is a schematic structural diagram of a rigid-flex board with only one golden finger provided by an embodiment of the present application;

Fig. 4 is a structural schematic diagram of a stacking method provided by an embodiment of the present application;

Fig. 5 is a structural schematic diagram of another stacking method provided by an embodiment of the present application;

Fig. 6 is a schematic structural diagram of a window opening method provided by an embodiment of the present application;

FIG. 7 is a schematic structural diagram of an outline figure of a bending area provided by an embodiment of the present application.

Detailed ways

In the description of the embodiments of the present application, multiple means more than two. Greater than, less than, exceeding, etc. are understood as not including the original number, above, below, within, etc. are understood as including the original number, and "at least one" means one or more "at least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. If there is a description of "first", "second", etc., it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the indicated The sequence relationship of the technical characteristics.

It should be noted that words such as setup, installation, and connection in the embodiments of the present application should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the embodiments of the present application in combination with the specific content of the technical solution. For example, the term "connected" may be mechanically connected, may be electrically connected or may communicate with each other; may be directly connected, or may be indirectly connected through an intermediary.

In the description of the embodiments of the present application, reference is made to the terms "one embodiment/implementation", "another embodiment/embodiment" or "certain embodiments/embodiments", "in the foregoing embodiments/embodiments", etc. The description means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least two embodiments or implementations of the present disclosure. In this disclosure, schematic representations of the above terms do not necessarily refer to the same example or implementation. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or implementations.

It should be noted that the technical features involved in each embodiment of the present application described below can be combined as long as there is no conflict between them.

Referring to Fig. 1 to Fig. 7, in the embodiment of the present application, a method of manufacturing a rigid-flex board is provided, including but not limited to S1, S2, S3, S4, S5, S6 and S7:

In S1, a soft board layer 1, a prepreg 3 and a hard board layer 2 are provided; the soft board layer is provided with a bending area, the bending area is provided with gold fingers, and the hard board layer is provided with a first area, so The first area is an area in the hard ply that is not covered by the prepreg. Among them, the soft board layer 1 and the hard board layer 2 need to be laminated with prepreg 3, and then pressed together. The second prepreg between the soft board layer 1 and the hard board layer 2 needs to be windowed, and the windowed area needs to be larger than the area of the first covering film. Therefore, in the windowed area, there is no prepreg coverage, and this area is first area.

In S2, pasting a first covering film on the surface of the bending area.

In one embodiment, referring to FIG. 2 , the flexible board layer 1 includes a bending area 110 on which the gold finger is disposed, and the gold finger can move within a certain range through the bending area 110 . In step S2, it is necessary to stick the first cover film 15 on the surface of the bending area 110, so as to protect the bending area 110, so as to effectively improve the quality of the rigid-flex board. It can be understood that pasting the first covering film 15 can act as a glue barrier, protecting the bending area 110 from being corroded by glue or other chemicals in the subsequent pressing and wet process.

In S3 , making an outline corresponding to the bending area, the outline being smaller than the first covering film.

In one embodiment, after the step S2 , it is necessary to make the outline pattern 120 corresponding to the bending area 110 , as shown in FIG. 2 and FIG. 7 , the size of the outline pattern 120 is smaller than the size of the first covering film.

In S4, a protective tape is pasted on the surface of the designated bending area, and the designated bending area is the bending area where the outermost flexible board layer faces the copper foil layer.

The protective tape 14 of this embodiment has high temperature resistance and has double-sided adhesiveness, that is, the first side of the protective tape 14 has low viscosity and is attached to the surface of the soft board layer 1; while the second side of the protective tape 14 has high viscosity. , in contact with the outer copper foil 12 or the prepreg 3 . The protective tape 14 can provide a physical bonding force with the outer copper foil 12 of the circuit board and the outer layer copper of the soft board layer 1, so that the outer layer copper foil 12 of the circuit board is indirectly pressed on the soft board layer 1 through the protective tape 14 superior. Since the protective tape 14 and the outer layer copper of the soft board layer 1 have only physical bonding force, the protective tape 14 and the outer layer copper foil 12 of the circuit board are easier to remove from the surface of the soft board layer 1, that is, it is easier to perform the opening operation, and at the same time Contoured grooves that block resin flow into the bend area. In one embodiment, if the prepreg 3 is not subjected to window opening or is only grooved along the shape of the bending area in the subsequent process, the prepreg 3 is in contact with the protective tape 14 instead of the copper foil 12 . Similarly, the protective tape 14 can provide a physical bonding force with the outer layer copper of the prepreg 3 and the soft board layer 1, so that the prepreg 3 is indirectly pressed on the soft board layer 1 through the protective tape 14, so that the protective tape 14 and the prepreg 3. It is easier to remove from the surface of the soft board layer 1, that is, it is easier to perform the opening operation.

In addition, in order to further increase the physical bonding force between the aforementioned protective tape 14 and the copper foil 12 on the outer layer of the circuit board, the tape can also be roughened so that the surface of the tape has a certain roughness, thereby increasing the physical bond between the protective tape 14 and the copper foil 12. Binding force.

In one embodiment, the protective tape 14 is a single-sided tape, and the manufacturing method further includes:

Pre-attach the adhesive side of the single-sided tape to the surface of the soft board layer 1;

The invalid area of the single-sided tape is removed, and the effective area of the single-sided tape is retained. The position of the effective area is consistent with the position of the bending area 110 . Wherein, the size of the effective area only needs to ensure that it can cover the shape groove of the bending area 110 , and the size of the effective area can be the same as the first covering film 15 or slightly smaller than the first covering film 15 . In this step, you can first cut the single-sided tape equal to the size of the prepreg 3, and attach the single-sided tape to the surface of the soft board layer 1 to ensure that there is no gap on the surface of the tape and the soft board, which can prevent resin from forming during the lamination process. It flows between the soft board and the tape.

In one embodiment, laser cutting may be used to cut the single-sided tape along the boundary line between the effective area and the invalid area, and then tear off the invalid area of the single-sided tape.

In one embodiment, the protective tape 14 is a double-sided tape, and the manufacturing method also includes:

Paste the viscous side of the double-sided tape on the surface facing the bending area 110 of the prepreg 3 in advance; or, attach the viscous side of the double-sided tape to the soft board layer in advance 1's surface facing the prepreg 3.

The invalid area of the double-sided tape is removed, and the effective area of the double-sided tape is reserved, and the position of the effective area is consistent with the position of the bending area 110 . Similarly, the size of the effective area only needs to ensure that it can cover the shape groove of the bending area 110 , and the size of the effective area can be the same as the first covering film 15 or slightly smaller than the first covering film 15 .

In S5, pasting a second covering film on the first region.

Referring to FIG. 3 , the second prepreg 3 disposed between the soft board layer 1 and the hard board layer 2 needs to be windowed, and after the windowing treatment, a first region 210 not covered by the prepreg 3 will be formed. Because the prepreg in this area has been window-opened, it is necessary to paste a second cover film 22 to fill the gap in this area to reduce pressure loss and prevent the glue from flowing between the soft board layer 1 and the hard board layer 2 to cause the hard board Layer 1 adjacent to layer 2 cannot be bent.

In one embodiment, the rigid-flex board includes a plurality of soft board layers, and the manufacturing method further includes:

A window is opened on the first prepreg and the second prepreg stacked between the two soft board layers, and the size of the window area is larger than the size of the first covering film. In this step, the first prepreg is stacked between two adjacent soft board layers 1, and the second prepreg is stacked between the soft board layer 1 and the hard board layer 2. The prepreg and the second prepreg are subjected to window opening treatment, so as to prevent the prepreg from flowing into the bending area 110 in subsequent processes, causing damage to the bending area 110 . Among them, the window opening method includes laser cutting, milling window, etc., and can also be stamped into a prepreg with a suitable shape by mold stamping.

In addition, the window area of the prepreg 3 bonded to the outer layer copper foil 12 of the circuit board can also be grooved along the shape of the bending area 110 . Because the glass fiber at the grooved position of the prepreg is broken, the resin fills the groove again during the subsequent lamination process, so there is only resin in the groove without glass fiber, which is convenient for subsequent uncapping operations.

In S6, the boards are stacked and pressed sequentially, so that the soft board layer and the hard board layer are stacked in sequence to obtain a mother board.

A prepreg 3 needs to be stacked between the two sub-boards, so as to achieve press-fitting and fixing between the two sub-boards after the pressing process, so that the prepared mother board has a stable press-fit structure. Among them, the sub-board includes a soft board layer 1 and a hard board layer 2, that is, between two adjacent soft board layers 1, between a soft board layer 1 and a hard board layer 2, and between two adjacent hard board layers 2 need to be laminated. Prepreg 3 is placed. In an embodiment, one or more gold fingers can be designed on the PCB according to actual needs. When there is only one gold finger on the PCB, the board stacking method is shown in Figure 4, and a soft board layer 1 and a hard board layer 2 need to be pressed together. When there are multiple gold fingers on the PCB, the board stacking method is shown in Figure 5. Multiple soft board layers 1 are stacked together in sequence, and then multiple hard board layers 2 corresponding to the number of soft board layers 1 are stacked in sequence. board together, and then press a plurality of soft board layers 1 and a plurality of hard board layers 2 .

In one embodiment, referring to FIG. 4 , during the pressing process, the copper foil 12 is indirectly pressed on the surface of the soft board layer 1 through the prepreg 3 and the protective tape 14 , and the prepreg 3 is indirectly bonded to the soft board layer 1 through the protective tape 14 The surface of the soft board layer 1 does not need to be etched on the outer layer of copper except the crimping hole area 20, which effectively reduces the difficulty of PCB production, and makes the soft board layer 1 not increase the thickness of the finished PCB due to the remaining prepreg 3, so as not to High and low steps will be formed due to the prepreg 3 remaining in the soft board layer 1, which can effectively improve the levelness of the PCB surface, reduce the difficulty of subsequent component insertion and installation on the PCB, and effectively improve user experience.

In S7, the first designated area of the motherboard is opened, and the protective tape is removed, the first designated area is the base material and the copper foil outside the bending area of the soft board layer.

Among them, when making the subsequent outer layer graphics, a certain width of copper is etched around the bending area corresponding to the surface copper foil, and solder mask and surface treatment are made. No copper is printed on the copper-free area around the bending area corresponding to the surface copper foil. It is only necessary to follow the deep groove formed by etching and solder mask to directly tear off the surface cover of the soft board area in a guided manner to complete the opening operation. In an embodiment, when the prepreg 3 in the first designated area is not subjected to groove or window opening, it can also be opened by laser cutting or other methods. Specifically, as shown in FIG. 6 , the copper foil 12 on the outside of the mother board and the periphery of the substrate 3 corresponding to the bending area are laser cut to form deep grooves, and then the cover outside the bending area is lifted along the deep grooves. After the cover is opened, the protective tape exposed after the cover needs to be removed.

In an embodiment, before the step S1, it also includes: making inner-layer graphics of each layer of core boards, and performing browning treatment on each layer of core boards.

Referring to FIG. 3 , the core board includes the first core board 11 in the soft board layer 1 and the second core board 21 in the hard board layer 2. The purpose of this step is to make the core boards of each layer in the daughter board and the The browning chemical solution reacts to form a dense organic browning film on the copper surface of the core board to enhance the bonding force between the core boards of each layer and the corresponding prepreg 3 and improve the pressing stability of the core boards of each layer. It is worth noting that before lamination, prepregs 3 need to be stacked between adjacent core boards, and the prepregs 3 are respectively combined with adjacent core boards under pressure, thereby realizing press-fitting and fixing between adjacent core boards.

In this embodiment, it is necessary to perform surface treatment on the gold finger, that is, to perform gold plating treatment. Because the communication signal current is relatively weak, and the contact resistance during wiring is usually a relatively large value, and gold is the metal with the highest conductivity in nature. If other metals are used as fingers, then during this contact process will be There is a relatively large power loss, and even the use of metals with ferromagnetic effects will cause electromagnetic interference, which will deteriorate and distort the original signal.

In an embodiment, the manufacturing method further includes: attaching reinforcement to a second designated area of the bending area, and the second designated area is the area on the other side of the soft board layer corresponding to the golden finger.

Referring to Fig. 2, in this embodiment, it is necessary to paste reinforcement on the second designated area, specifically, the second designated area is on the surface of the bending area 110, after the first covering film is pasted on the surface of the bending area, it can be continued on the first The surface of the covering film is pasted with reinforcement 16 to avoid severe deformation of the bending area 110, thereby increasing the service life of the PCB.

In one embodiment, after affixing the protective tape on the surface of the bending area, it further includes: making the outer layer pattern of the motherboard; and performing green oil treatment, surface treatment and shape treatment on the motherboard.

In this embodiment, by performing green oil treatment, surface treatment and shape treatment on the mother board, the PCB can be better protected, thereby effectively improving the quality of the PCB and improving user experience.

A method for manufacturing a rigid-flex board and a circuit board disclosed in this application have the following beneficial effects:

In this embodiment, the first cover film is pasted on the surface of the bending area of the flexible board, and the shape corresponding to the bending area is smaller than the first cover film, and then a protective tape is attached on the surface of the bending area to protect the bending area. Folding area, and a second cover film on the first area of the hard board layer, and then sequentially laminate and press, so that the soft board layer and the hard board layer are stacked in sequence to obtain a mother board, and then the The first designated area on the outermost side of the bending area of the flex ply of the mother board is opened and the protective tape is removed to obtain a rigid-flex board. Through this fabrication method of the rigid-flex board, it is possible to design the golden finger at any position in the board according to the needs of the user.

In the embodiment of the present application, the corresponding circuit board can also be manufactured through the manufacturing method described in the previous embodiments.

Claims

A method for manufacturing a rigid-flex board, the method comprising:

Provide a soft board layer, a prepreg and a hard board layer; the soft board layer is provided with a bending area, and the bending area is provided with golden fingers, and the hard board layer is provided with a first area, and the first area is the the area in the hard ply that is not covered by the prepreg;

pasting a first covering film on the surface of the bending area;

making an outline corresponding to the bending area, the outline being smaller than the first covering film;

Paste protective tape on the surface of the designated bending area, the designated bending area is the bending area facing the copper foil layer with the outermost soft board layer;

pasting a second covering film on the first area;

stacking and pressing the plates sequentially, so that the soft board layer and the hard board layer are sequentially stacked to obtain a mother board; and

Uncovering the first designated area of the motherboard, and removing the protective tape, the first designated area is the base material and copper foil outside the bending area of the soft board layer.
The manufacturing method of the rigid-flex board according to claim 1, further comprising:

Reinforcement is attached to a second designated area of the bending area, and the second designated area is the area on the other side of the soft board layer corresponding to the golden finger.
The manufacturing method of the rigid-flex board according to claim 1, wherein the protective tape is a single-sided tape, and the manufacturing method comprises:

adhering the adhesive side of the single-sided tape to the surface of the soft board layer in advance;

The invalid area of the single-sided tape is removed, and the effective area of the single-sided tape is reserved, so that the effective area covers the shape groove corresponding to the bending area.
The manufacturing method of the rigid-flex board according to claim 1, wherein the protective tape is a double-sided adhesive tape, and the manufacturing method comprises:

The first adhesive surface of the double-sided tape is attached to the surface of the bonding sheet facing the soft board layer in advance; or, the second adhesive surface of the double-sided adhesive tape is attached in advance To the surface of the soft board layer facing the adhesive sheet; the viscosity of the first adhesive surface is greater than the viscosity of the second adhesive surface; and

The invalid area of the double-sided tape is removed, and the effective area of the double-sided tape is reserved, so that the effective area covers the shape groove corresponding to the bending area.
The method for manufacturing a rigid-flex board according to claim 1, wherein the rigid-flex board includes a plurality of soft board layers, and the prepreg includes a first layer stacked between two soft board layers. A prepreg and a second prepreg stacked between the soft board layer and the hard board layer, the manufacturing method further includes: opening a window on the first prepreg and the second prepreg, and opening a window area The size is larger than the size of the first covering film.
The method for manufacturing a rigid-flex board according to claim 1, further comprising: performing surface treatment on the golden fingers.
According to the manufacturing method of rigid-flex board according to claim 1, before pasting the first cover film on the surface of the bending area, it also includes: making the inner layer graphics of each layer of core boards; and browning each layer of core boards processing.
According to the method for making a rigid-flex board according to claim 1, after affixing a protective tape on the surface of the designated bending area, it further includes: providing copper foil; and laminating and pressing the plates sequentially so that the protective tape, The prepreg and copper foil are stacked sequentially.
According to the manufacturing method of the rigid-flex board according to claim 1, after the laminated boards are laminated and pressed in order, so that the soft board layer and the hard board layer are sequentially stacked to obtain the mother board, it also includes: making The outer pattern of the motherboard; and the green oil treatment, surface treatment and shape treatment of the motherboard.
A circuit board manufactured by the method for manufacturing a rigid-flex board according to any one of claims 1 to 9.