CN117062346A - Semi-flexible circuit board and manufacturing method thereof - Google Patents

Abstract

The embodiment of the invention relates to the technical field of circuit boards, and discloses a semi-flexible circuit board and a manufacturing method thereof, wherein the method comprises the following steps: determining a target material layer corresponding to the bottom position of the bending region of the semi-flexible circuit board according to the depth and the width of the bending region of the semi-flexible circuit board; the semi-flexible circuit board comprises a plurality of circuit layers which are connected with each other through a non-adhesive PP; when the circuit layer is CCL, the target material layer is a non-gummosis PP layer, and when the circuit layer is CCL with the lower surface copper foil removed, the dielectric layer of CCL with the lower surface copper foil removed is connected with the non-gummosis PP layer, and the target material layer is the dielectric layer and the non-gummosis PP layer of the lower circuit layer; and placing a preset isolation material in a blind groove of a bending area gong of the target material layer, sequentially stacking all circuit layers, and then performing gluing treatment to obtain a bending area of the circuit board to be uncapped, performing depth control gong, stopping and uncapping to remove the isolation material when the isolation material is gong, so as to obtain the semi-flexible circuit board. Through the mode, the embodiment of the invention realizes the semi-flexible circuit board with higher availability.

Description

Semi-flexible circuit board and manufacturing method thereof

Technical Field

The embodiment of the invention relates to the technical field of circuit boards, in particular to a semi-flexible circuit board and a manufacturing method thereof.

Background

The semi-flexible circuit board adopts a numerical control milling machine technology to control the depth cutting of the circuit board, so that a certain thickness is reserved in a bending area, and therefore, the bendable circuit board is manufactured, and the semi-flexible circuit board can replace the existing soft and hard combined board in a certain range. When the existing semi-flexible circuit board is processed, a bending area is generally realized in a depth-control gong mode.

The inventors found in the implementation of the prior art that: the thickness precision control of the bending area manufactured by the traditional depth control gong mode is poor, the appearance of the depth control gong flat area is rough and uneven, and the bending line is easily damaged, so that the bending effect and the application of the semi-flexible circuit board are affected. Therefore, a manufacturing scheme of the semi-flexible circuit board with more accurate control of the accuracy of the bending region, smoother bending region and higher availability is needed.

Disclosure of Invention

In view of the above problems, embodiments of the present invention provide a semi-flexible circuit board and a manufacturing method thereof, which are used for solving the problems in the prior art that the accuracy control of a bending region is low, and the bending region is rough, so that the usability of the semi-flexible circuit board is affected.

According to an aspect of the embodiment of the present invention, there is provided a method for manufacturing a semi-flexible circuit board, the method including:

Determining the depth and width of a bending area of the semi-flexible circuit board;

determining a target material layer corresponding to the bottom position of a bending region of the semi-flexible circuit board according to the depth and the width; the semi-flexible circuit board comprises a plurality of circuit layers, wherein the circuit layers are connected with each other through a non-adhesive PP; the circuit layer is CCL or CCL with the lower surface copper foil removed, when the circuit layer is CCL, the target material layer is a non-gummosis PP layer, when the circuit layer is CCL with the lower surface copper foil removed, the dielectric layer of the CCL with the lower surface copper foil removed is connected with the non-gummosis PP layer, and the target material layer is the dielectric layer and the non-gummosis PP layer of the lower circuit layer;

routing at least one blind groove at the bending area of the target material layer;

placing a preset isolation material in the blind groove, sequentially stacking the circuit layers, and then performing gluing treatment to obtain a circuit board to be uncapped;

and carrying out depth control gong on the bending area of the circuit board to be uncapped, stopping when gong to the isolating material, uncapping to remove the isolating material, and obtaining the semi-flexible circuit board.

In an alternative, the isolating material is a polyimide film.

In an alternative, the method further comprises:

determining the number of copper layers contained in a circuit layer below the bottom position of the bending region according to the depth and the thickness information of each layer of material of the semi-flexible circuit board;

when the number of copper layers is an odd number, determining the type of the material layer of the CCL closest to the bending region facing the bending region; the material layer is of a dielectric layer or copper foil;

when the type of the material layer facing the bending area is a medium layer, determining the target material layer as the medium layer and the non-gummosis PP layer of the lower circuit layer;

and when the number of copper layers is even, determining the target material layer as the non-gummosis PP layer.

In an alternative, the method further comprises:

when the target material layer is determined to be a dielectric layer and a non-gummosis PP layer of the lower circuit layer, at least one blind groove is formed in a corresponding position on the surface of the lower circuit layer, where the dielectric layer and the non-gummosis PP layer are connected, respectively; the area of each blind groove is smaller than the area of the bottom of the bending area.

In an alternative, the method further comprises:

and when the target material layer is determined to be the non-gummosis PP layer, a blind groove with the area equal to the area of the bottom position of the bending area is milled on the non-gummosis PP layer.

In an alternative, the method further comprises:

and carrying out positioning marks on the surface of the semi-flexible circuit board corresponding to the position of the blind groove so as to start the action of the depth control gong from the positioning marks.

In an alternative, the method further comprises:

when the circuit layers are pressed, the dielectric layers of the lower circuit layer and the blind grooves on the non-gummosis PP layer are aligned, so that the non-gummosis PP flows into the blind grooves on the dielectric layers of the lower circuit layer when being pressed to flow.

In an alternative, the method further comprises:

disposing an adhesive on the release material;

the isolating material is adhesively secured in the blind slot by the adhesive.

In an alternative, the method further comprises:

obtaining the thickness of the non-gummosis PP layer;

and determining the thickness of the isolating material and the adhesive according to the thickness of the non-gummosis PP layer, so that the total thickness of the isolating material and the adhesive is greater than or equal to the thickness of the non-gummosis PP layer.

According to another aspect of the embodiments of the present invention, there is provided a semi-flexible circuit board, which is characterized in that the semi-flexible circuit board is manufactured according to the manufacturing method embodiment of the semi-flexible circuit board according to any one of the preceding claims.

According to the embodiment of the invention, the depth and the width of the bending region of the semi-flexible circuit board are determined, and the target material layer corresponding to the bottom position of the bending region of the semi-flexible circuit board is determined according to the depth and the width; the semi-flexible circuit board comprises a plurality of circuit layers, wherein the circuit layers are connected with each other through a non-gumming PP (pre-preg) layer; the circuit layer is CCL (Copper Clad Laminate ) or CCL with lower surface copper foil removed, when the circuit layer is CCL, the target material layer is a non-gummosis PP layer, when the circuit layer is CCL with lower surface copper foil removed, the dielectric layer of CCL with lower surface copper foil removed is connected with the non-gummosis PP layer, and the target material layer is the dielectric layer and the non-gummosis PP layer of the lower circuit layer; routing at least one blind groove at the bending area of the target material layer; placing a preset isolation material in the blind groove, sequentially stacking the circuit layers, and then performing gluing treatment to obtain a circuit board to be uncapped; and carrying out depth control gong on the bending area of the circuit board to be uncapped, stopping when gong to the isolating material, uncapping to remove the isolating material, and obtaining the semi-flexible circuit board. Therefore, the problem that the accuracy control is poor and the usability of the semi-flexible circuit board is affected due to the fact that the surface unevenness of the bending region is poor is distinguished from the fact that a bending region is manufactured by a depth-controlling gong in the prior art, and the semi-flexible circuit board is obtained by turning at least one blind groove at the bending region position on a target material layer corresponding to the bottom position of the bending region, and after isolating materials are placed in the blind groove, the fact that the surface of the bending region is directly gong like the existing depth-controlling gong when the depth-controlling gong is controlled is avoided, the isolation materials are stopped when the bending region is gong to the isolating materials, and the semi-flexible circuit board is obtained by uncovering, so that the semi-flexible circuit board with the smooth surface of the bending region and the more accurate accuracy control and higher usability is achieved. The circuit layer is obtained by processing the CCL, the CCL dielectric layer has smooth surface and consistent thickness compared with the traditional mechanical depth control, the tolerance of the bending area depends on the CCL tolerance, and the tolerance of the non-depth control machine can reach +/-0.01 mm at most. And the depth control isolation material can use a PI film with a slightly higher thickness than a blind groove, is resistant to high temperature and has a thickness higher than the depth control precision, so that a common depth control precision gong machine can be used for uncovering, and the purchase cost of high-precision equipment in the processing process of a semi-flexible circuit board is saved.

Further, in the embodiment of the present invention, when a plurality of circuit layers are glued, after the copper foil on the lower surface of the circuit layer needs to be removed in a part of the scene, the lower surface copper foil of the circuit layer needs to be laminated with other circuit layers, which may cause that the material layer corresponding to the bottom position of the bending region is a non-adhesive PP layer for gluing the circuit layer, or may be a dielectric layer such as FR-4 exposed after the copper foil on the surface is removed by the CCL, and the dielectric layer is directly connected with the non-adhesive PP layer, and a certain flowability of the non-adhesive PP layer is considered when the circuit layer is pressed, so that when the circuit layer is the CCL with the lower surface copper foil removed, the dielectric layer with the lower surface copper foil removed is connected with the non-adhesive PP layer, and the target material layer is the dielectric layer and the non-adhesive PP layer of the lower circuit layer, thereby being convenient for the non-adhesive PP layer to flow into the blind groove on the dielectric layer of the lower circuit layer through the blind groove on the non-adhesive PP layer when the non-adhesive PP layer flows under pressure, so as to further improve the usability of the semi-flexible board.

The foregoing description is only an overview of the technical solutions of the embodiments of the present invention, and may be implemented according to the content of the specification, so that the technical means of the embodiments of the present invention can be more clearly understood, and the following specific embodiments of the present invention are given for clarity and understanding.

Drawings

The drawings are only for purposes of illustrating embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to designate like parts throughout the figures. In the drawings:

fig. 1 is a schematic flow chart of a method for manufacturing a semi-flexible circuit board according to an embodiment of the present invention;

fig. 2 shows a schematic structural diagram of a semi-flexible circuit board provided by the embodiment of the invention when the number of copper layers below a bending region is an odd number;

fig. 3 is a schematic structural diagram of a semi-flexible circuit board provided by the embodiment of the invention when the number of copper layers below a bending region is even;

in the above figures:

m1: first material, M2: second material, M3: third material, M4: fourth material, soldmask: solder mask layer, copper: copper layer, core: dielectric layer, prepreg: prepreg, no flow PP: non-gummosis PP, M5: fifth material, M6: sixth material, M7: seventh material, M8: eighth material.

Detailed Description

Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention may be embodied in various forms and should not be limited to the embodiments set forth herein.

Prior art will be further described before describing embodiments of the present invention:

the conventional circuit board generally starts to control the depth gong from the surface of the pre-pressed multilayer circuit board according to the depth and width of the bending region until the gong reaches a specific depth, and then the circuit board with the bending region is obtained. The problem is that the bending area is directly obtained by a milling cutter for controlling the depth, and the surface of the bending area is generally uneven, so that the bending performance of the bending area can be affected. And because of the difference of the thickness of the plates or the difference of the routing platforms (such as 4 shafts or six shafts), the residual thickness precision of the bending area in the depth control routing is poor, and particularly when the residual thickness is very thin, such as 0.1 millimeter, the thickness of the bending area can be even possibly routed to conductive layers such as copper and the like below the bending area, thereby further influencing the usability of the semi-flexible circuit board.

Therefore, there is a need for a semi-flexible circuit board with higher processing accuracy, smoother surface in the bending region, and higher usability.

Fig. 1 shows a flowchart of a method for manufacturing a semi-flexible circuit board according to an embodiment of the present invention, which is performed by a circuit board processing apparatus. The circuit board processing equipment may include etchers, cutters, and the like.

As shown in fig. 1, the method comprises the steps of:

Step 10: and determining the depth and the width of the bending area of the semi-flexible circuit board.

The bending area of the semi-flexible circuit board has static bending capability.

It will be appreciated that the thinner the bending zone, the smaller the bending radius, but given that the bending zone is typically a glass brittle material, and that there are typically testing, inspection, packaging, shipping, mounting, assembly, etc. steps after processing to obtain the bending zone, the thinner the bending zone, the more easily damaged, and therefore the depth and width of the bending zone can be set as desired. The semi-flexible circuit board is manufactured by connecting a plurality of circuit layers through non-adhesive PP, and performing depth control gong in a bending area. Therefore, the depth and width of the bending region of the half-flexible circuit board should be determined before manufacturing. The depth and width of the bending region can be determined by combining the thickness of each circuit layer, the PP glue and the number of the circuit layers according to the design requirement of the circuit board.

Step 20: and determining a target material layer corresponding to the bottom position of the bending region of the semi-flexible circuit board according to the depth and the width.

Considering that the conventional circuit board is generally obtained by sequentially laminating a plurality of copper foils and PP prepregs, the problem that the bonding force of copper foils on the surface of a bending area processed on the circuit board is low exists, in the embodiment of the invention, a CCL (CCL) is adopted or the CCL of which the copper foil on the lower surface is removed is adopted as a circuit layer, and the bonding force of the copper foil on the surface of the CCL and a dielectric layer meets the standard requirement, so that the situation that the adhesion force is poor and the thermal shock is not resistant due to pressure loss in the conventional lamination process of a multilayer material is avoided.

Specifically, the circuit layer in the embodiment of the invention adopts a CCL or a CCL with the lower surface copper foil removed, when the circuit layer is the CCL, the target material layer is a non-gummosis PP layer, when the circuit layer is the CCL with the lower surface copper foil removed, the dielectric layer with the lower surface copper foil removed is connected with the non-gummosis PP layer, and the target material layer is the dielectric layer and the non-gummosis PP layer of the lower circuit layer.

When all the circuit layers are CCLs, the CCLs are directly glued through the non-gummed PP layer to obtain the circuit board to be processed in the bending area. When the circuit layer includes the CCL and the CCL with the lower surface copper foil removed, at least one CCL and at least one CCL with the lower surface copper foil removed are glued through the non-gummed PP layer to obtain a circuit board to be processed in the bending region.

The target material layer is used for placing isolation materials, the isolation materials can improve the depth control gong precision, the isolation materials are used as processing positioning marks of bending areas when the depth control gong is performed, and when the depth control gong reaches the isolation materials, the isolation materials are taken out to directly obtain the bending areas with flat surfaces. Specifically, blind grooves can be formed in the target material layer, and isolation materials are placed through the blind grooves.

According to the embodiment of the invention, the target material layer at the bottom of the bending region is determined according to the depth and the structural information of the semi-flexible circuit board, wherein the structural information Comprises CCL (CCL) of each circuit layer in the semi-flexible circuit board or CCL of removing copper foil on the lower surface. Specifically, when the circuit layer is a CCL, the plurality of CCLs are directly glued through the non-gummosis PP layer, that is, the non-gummosis PP layer is directly connected with the copper layer on the surface of the CCL, it is easy to understand that the copper layer surface needs to be protected and cannot be directly exposed as the surface of the bending region, and therefore, when the circuit layer is a CCL, the target material layer is the non-gummosis PP layer.

It can be understood that, under the influence of the thickness of the plate and the actual processing requirement, in some situations where only one-sided copper foil is needed to conduct electricity, for example, for a multi-layer semi-flexible circuit board, when the multi-layer semi-flexible circuit board to be designed is an odd-layer circuit board, etching is performed on a copper foil on a certain surface of a CCL, thus, unlike a circuit board in which a plurality of CLLs are glued directly through a non-gummosis PP layer to obtain a bending region to be gong, in a circuit board in which etching is performed on a copper foil on the lower surface of the CCL, a dielectric layer (such as an FR-4 layer) of the CCL in which the copper foil on the lower surface of the CCL is removed is directly connected with the non-gummosis PP layer. In view of that the non-gumming PP layer still generates certain fluidity when being subjected to pressure, in order to facilitate the flow of the non-gumming PP layer and accommodate the non-gumming PP flowing down from the upper layer, blind grooves may be respectively formed on the non-gumming PP layer and the dielectric layer of the CCL for removing the copper foil on the lower surface, i.e. when the circuit layer is the CCL for removing the copper foil on the lower surface, the dielectric layer of the CCL for removing the copper foil on the lower surface is connected with the non-gumming PP layer, and the target material layer is the dielectric layer of the circuit layer on the lower layer and the non-gumming PP layer. Wherein, the lower surface copper foil refers to a surface copper foil layer of the CCL near the bottom of the bending area. For example, when the circuit layer is the CCL with the lower surface copper foil removed, the depth of the inflection region may be 108 microns, wherein the thickness of the FR-4 dielectric layer below the inflection region (i.e., the dielectric layer of the CCL with the lower surface copper foil removed) is 50 microns, the thickness of the copper layer below the FR-4 dielectric layer is 38 microns, and the thickness of the solder mask layer outside the copper layer is 20 microns.

Specifically, considering that the number of copper layers of the semi-flexible circuit board is affected by circuit layers of different types (such as whether the lower surface copper foil of the CCL is removed), and thus the number of copper layers at the bottom of the bending region is also affected, the type of the circuit layers contained in the semi-flexible circuit board can be determined according to the number of copper layers at the bottom of the bending region, so that whether the dielectric layer of the CCL directly connected with the non-adhesive PP layer and with the lower surface copper foil removed is present is determined according to the type of the circuit layers, and thus the position of the target material layer is determined. Thus, in yet another embodiment of the present invention, step 20 further comprises:

step 201: and determining the number of copper layers contained in the circuit layer below the bottom position of the bending region according to the depth and the thickness information of each layer of material of the semi-flexible circuit board.

The thickness information of each layer of material of the semi-flexible circuit board comprises the layer information of the layer material in the semi-flexible circuit board and the thickness information thereof, for example, the first layer of the semi-flexible circuit board from top to bottom is CCL (without considering a solder mask layer) with the lower surface copper foil removed, the thickness of the CCL is 88 micrometers, the thickness of a dielectric layer of the CCL with the lower surface copper foil removed is 50 micrometers, and the thickness of a surface copper foil layer is 38 micrometers. The second layer was a non-tacky PP layer with a thickness of 50 microns, the third layer was a CCL with a thickness of 1200 microns, wherein the surface copper foil had a thickness of 35 microns and the middle dielectric layer (FR-4) had a thickness of 1130 microns. Specifically, the depth of the bending region is compared with the thickness of the semi-flexible circuit board, and the number of copper layers included in the circuit layer at the bottom of the bending region is obtained. For example, the semi-flexible circuit board includes 4 CCLs glued by a non-adhesive PP layer from top to bottom, wherein the thickness of the non-adhesive PP layer is 100 micrometers, the thickness of copper foil in the CCL is 38 micrometers, the thickness of a dielectric layer in the CCL is 50 micrometers, and the thickness of the solder mask layer is 20 micrometers, so that the total thickness of the semi-flexible circuit board is 844 micrometers, and the depth of the bending region is 736 micrometers, that is, the thickness of the bending region is 108 micrometers, and it can be determined that a layer of copper is included under the bending region.

Step 202: when the number of copper layers is an odd number, determining the type of the material layer of the CCL closest to the bending region facing the bending region; the material layer is a dielectric layer or a copper foil.

In consideration of the fact that when the multi-layered semi-flexible printed circuit board to be designed is an odd-layered printed circuit board, etching is performed on a certain surface copper foil of the CCL, and only the surface copper foil of the other surface of the CCL is left due to the removal of the surface copper foil of one surface of the CCL, the number of copper layers below the bottom position of the bending region is odd. Further, considering that there may be various placement modes between the CCL and the CCL with the lower surface copper foil removed, the type of the CCL closest to the bending region may be affected, and thus whether the medium layer is directly connected with the non-gummosis PP layer may be affected. Thus, when the number of copper layers is an odd number, further determining the type of material layer of the CCL closest to the inflection region facing the inflection region; the material layer is a dielectric layer or a copper foil.

Step 203: and when the type of the material layer facing the bending area is a dielectric layer, determining the target material layer as the dielectric layer and the non-gummosis PP layer of the lower circuit layer.

When the material layer facing the bending area is a dielectric layer, that is, there is a direct connection between the dielectric layer and the non-gummosis PP layer, and considering that the non-gummosis PP layer flows when being pressed, blind grooves need to be respectively formed on the dielectric layer and the non-gummosis PP layer, wherein the isolation material is placed and the flowing non-gummosis PP is accommodated.

Specifically, when the number of copper layers is 1, and the placement mode of the circuit layer is that the material layer facing the bending area is a dielectric layer, the structure of the semi-flexible circuit board may be as shown in fig. 2, where the circuit layer includes a first material M1 and a third material M3, the isolation material is a fourth material M4, the non-gummosis PP layer is a second material M2, and specifically, the processing and combined manufacturing processes of each material are as follows:

cutting, drilling, pattern transferring, etching and film removing CCL with double sides of 1.2 mm, AOI (Auto Optical Inspection, automatic optical detection) and milling two blind grooves on an L2 layer to obtain a first material M1; wherein 1oz represents a copper foil thickness of about 35 microns;

cutting and drilling 0.1 mm non-gumming PP, and milling a groove on a non-gumming PP layer near the L1 layer to serve as the second material M2;

etching off one copper side of the 0.05 mm copper-free CCL (or the CCL with no one copper side of the thin plate), and drilling to obtain a third material M3;

cutting, drilling and edge milling a 0.1 mm PI film attached with 0.025-0.05 mm AD glue to obtain a fourth material M4;

and (3) over-brown the first material M1, stacking the second material M2 up and down, wherein as shown in fig. 2, placing a fourth material M4 above the second material M2 with blind grooves in a groove PP, pre-fixing the AD glue in the middle of the blind grooves of the L2 layer, riveting and pressing after stacking the third material M3 up and down, targeting, drilling, copper deposition, pattern transfer, copper-tin electroplating, film stripping by etching, AOI (automatic optical imaging solder resist) and solder resist words (the specific solder resist can be liquid photo imaging solder resist), performing surface treatment and molding to obtain the circuit board to be uncapped.

And (3) deep routing is performed on the bending area of the circuit board to be uncapped, stopping routing until the fourth material M4 is reached, removing the fourth material M4 after uncapping, and finally repairing, cleaning and testing residual glue to obtain the semi-flexible circuit board shown in fig. 2.

Step 203: and when the number of copper layers is even, determining the target material layer as the non-gummosis PP layer.

Corresponding to step 202, when the circuit layers are CCLs, the number of copper layers under the bottom of the bending region is even. Therefore, when the number of copper layers is even, the target material layer is determined as the no-bleeding PP layer.

Specifically, when the number of copper layers below the bending region is 2, the structure of the semi-flexible circuit board may be as shown in fig. 3, where the circuit layer includes a fifth material M5 and a seventh material M7, the isolation material is an eighth material M8, and the non-gummosis PP layer is a sixth material M7, and specifically, the processing and combined manufacturing processes of each material are as follows:

cutting, drilling, pattern transferring, etching, stripping, AOI and L3 layer blind milling grooves (depth is 0.1-0.15 mm) on two (namely L3/L4 and L5/6 layers) CCLs with double faces of 1oz to obtain a fifth material M5;

cutting and drilling the 0.1 mm non-gumming PP to obtain a sixth material M6;

Making lines L2 and L7 on inner layers of the FR4 with 0.1 mm of copper-free surfaces of two CCLs (TOP/L2 and L7/BOT layers in FIG. 3), and carrying out whole-plate copper protection and drilling on outer layers L1 and L8 to obtain a seventh material M7;

cutting, drilling and edge milling are carried out on the 0.1 millimeter PI film attached with the AD glue with the thickness of 0.025-0.05 millimeter, and an eighth material M8 is obtained;

and (3) over-browning the fifth material M5, stacking the sixth material M6 up and down, pre-fixing the eighth material M8 in the middle of the blind groove of the L3 layer through AD glue, pre-stacking the eighth material M8 and the seventh material M7 in a layering manner, riveting and pressing, targeting, drilling, copper deposition, pattern transfer, copper-tin electroplating, etching film stripping, AOI, solder resist characters (specific solder resist can be liquid photoimageable solder resist), surface treatment and forming to obtain a circuit board to be uncapped, controlling the depth of the bending area of the circuit board to be uncapped, stopping when the eighth material M8 is reached, removing the eighth material M8 after uncapping, and finally repairing, cleaning and testing residual glue to obtain the semi-flexible circuit board shown in figure 3.

Step 30: and routing at least one blind groove at the bending area of the target material layer.

The blind groove is used for placing isolation materials, the isolation materials are used for achieving positioning of the bending area in the depth control gong process, and particularly, when the depth control gong is conducted on the semi-flexible circuit board until the isolation materials can be seen, removal of the isolation materials can be stopped, and the bending area with a flat surface is obtained.

Regarding the setting positions and the number of the blind grooves, considering that the non-adhesive PP layer still has certain fluidity when pressed, a space for accommodating the flowing non-adhesive PP layer is needed, and meanwhile, since the embodiment of the present invention obtains the bending area with a flat surface after pressing the circuit boards and then deep-milling to take out the isolation material, the area of the blind groove also needs to consider the influence on the decompression in the pressing process, therefore, in still another embodiment of the present invention, step 30 further includes:

step 301: when the target material layer is determined to be a dielectric layer and a non-gummosis PP layer of the lower circuit layer, at least one blind groove is formed in a corresponding position on the surface of the lower circuit layer, where the dielectric layer and the non-gummosis PP layer are connected, respectively; the area of each blind groove is smaller than the area of the bottom of the bending area.

Considering that the non-gummosis PP layer still has certain fluidity when being pressed, a space for accommodating the flowing non-gummosis PP layer is needed, so that at least one blind groove needs to be formed at a corresponding position on the surface of the dielectric layer of the lower circuit layer connected with the non-gummosis PP layer, and optionally, two blind grooves can be formed respectively. It can be understood that the position on the dielectric layer of the lower circuit layer corresponding to the bottom position of the bending region may be P1, and then the positions P2 corresponding to P1 on the surface connected with the non-gummosis PP layer are respectively formed by routing blind grooves on P1 and P2.

Further, considering that the non-adhesive PP layer on the upper layer of the dielectric layer of the lower circuit layer is provided with blind grooves, the thickness of the non-adhesive PP layer is about 100 micrometers, and the isolation material is generally made of flexible plates, such as polyimide films, the thickness of the polyimide films is about 0.1-0.2 millimeter, if the non-adhesive PP layer is completely hollowed as the blind grooves, the upper and lower materials at the blind grooves can be not tightly laminated, so that the thickness precision of a bending region is affected, and therefore, the area of the blind grooves at the corresponding positions on the surface where the dielectric layer of the lower circuit layer is connected with the non-adhesive PP layer is smaller than the area of the bottom positions of the bending region.

Correspondingly, when it is determined that the target material layer is only the non-gummosis PP layer, no blind grooves are formed on both the upper layer and the lower layer to be pressed, so that no consideration is required for the problem of pressure loss, and therefore, in still another embodiment of the present invention, step 30 further includes:

step 302: and when the target material layer is determined to be the non-gummosis PP layer, a blind groove with the area equal to the area of the bottom position of the bending area is milled on the non-gummosis PP layer.

Correspondingly, when the target material layer is determined to be the non-gummosis PP layer, the blind groove on the non-gummosis PP layer is only used as a space for placing isolation materials, so that the blind groove with the whole area of gong is empty, namely, the blind groove with the area equal to the area of the bottom position of the bending area on the non-gummosis PP layer can be designed, and the problem of pressure loss after taking the whole area of the material layer as the blind groove is empty is not considered.

Step 40: and placing a preset isolation material in the blind groove, sequentially stacking the circuit layers, and then performing gluing treatment to obtain the circuit board to be uncapped.

Among them, the insulating material is preferably a material which is resistant to high temperature, easy to process, and has a certain flexibility. Specifically, the thickness of the isolation material can be 0.1-0.15 mm, and through the positioning function of the isolation material, when the depth control is performed on the semi-flexible circuit board, the depth control function precision is not high, and the cover opening depth control interface is performed on universal equipment which can achieve +/-0.10 mm to obtain the semi-flexible circuit board with the standard surface copper foil wiring adhesive force.

Further, considering the hardness of copper foil commonly used in the circuit board field is large, the thickness thereof may affect the thickness of the material layer above it when pressed, for example, when the copper foil as a spacer is thick, the material layer above it may be thinned, and when the copper foil is thin, the material layer above it may be thick. On the other hand, copper is relatively high in cost and not environment-friendly, and if residues exist during removal, short circuits may be caused, so that the performance of the circuit board is affected, on the basis of the fact that the hardness of the polyimide film is smaller, a cutter is not easy to damage during processing, the polyimide film is not conductive, the electrical performance of the circuit board is not affected even if residues exist, and the polyimide film is easier to process, easy to obtain, relatively cheap and environment-friendly, so that the isolation material in the embodiment of the invention is preferably the polyimide film.

In the embodiment of the present invention, when the plurality of circuit layers are laminated, the dielectric layers of the lower circuit layer and the blind grooves on the non-adhesive PP layer are aligned so that the non-adhesive PP flows into the blind grooves on the dielectric layers of the lower circuit layer when being pressed and flowing.

It can be understood that when a plurality of circuit layers are stacked, the dielectric layer of the lower circuit layer and the blind grooves on the non-gummosis PP layer are aligned and then pressed.

Further, in order to avoid displacement of the isolation material from the blind groove during the pressing process, thereby resulting in a reduced processing accuracy of the bending region, in a further embodiment of the present invention, step 40 further includes:

step 401: an adhesive is disposed on the release material.

Wherein, when the isolating material is fixed by the adhesive, in order to facilitate the isolating material to be taken out from the blind groove, the adhesive can be selected from acrylic acid hot melt adhesive, namely adhesive with better adhesive rheological property such as AD (adhesive) adhesive.

Step 402: the isolating material is adhesively secured in the blind slot by the adhesive.

Specifically, an adhesive is bonded to one side of the release material and the side is adhesively secured in the blind slot.

Further, considering that there is a certain thickness of the adhesive, and if the thickness of the adhesive plus the thickness of the release material is smaller than the thickness of the non-gumming PP layer, there will be a flow of the non-gumming PP layer into the cavity above the release material when pressed, thereby affecting the removal of the release material, and thus, in a further embodiment of the present invention, step 401 comprises:

step 4011: and obtaining the thickness of the non-gummosis PP layer.

For example, the thickness of the no-flow PP may be 100 microns.

Step 4012: and determining the thickness of the isolating material and the adhesive according to the thickness of the non-gummosis PP layer, so that the total thickness of the isolating material and the adhesive is greater than or equal to the thickness of the non-gummosis PP layer.

For example, the release material may be a PI film having a thickness of 0.1 mm and the adhesive may be an AD glue having a thickness of 0.025-0.05 mm, such that the total thickness of the release material and the adhesive is 0.125-0.15 mm, which is greater than 100 microns of the non-gumming PP. Therefore, when the non-gumming PP layer and the dielectric layer of the lower circuit layer are pressed, the non-gumming PP layer flows to the isolation material in the blind groove on the dielectric layer of the lower circuit layer below the non-gumming PP layer, so that the isolation material is covered and is difficult to take out, and the processing efficiency of the semi-flexible circuit board is affected.

Step 50: and carrying out depth control gong on the bending area of the circuit board to be uncapped, stopping when gong to the isolating material, uncapping to remove the isolating material, and obtaining the semi-flexible circuit board.

The method comprises the steps of directly routing out a bending area through a depth control routing mode in the prior art, wherein the thickness accuracy control is poor, the appearance of the bending area with the depth control routing flat is rough and uneven, the residual thickness is difficult to be less than 0.1 mm, a bending line is easy to damage, and the bending effect and the application of a semi-flexible circuit board are affected.

Specifically, the embodiment of the invention can judge whether the isolation material is milled or not by visual observation, such as by milling a certain depth, when the isolation material exists, the thickness of the isolation material is generally about 0.15 mm, and a common depth control precision milling machine can easily control the milling to PI without milling to a bending area substrate under the PI.

The circuit layer in the embodiment of the invention is CCL, so that the dielectric layer has smooth surface and consistent thickness compared with the traditional mechanical depth control, the tolerance of the dielectric layer depends on the tolerance of the CCL, but not the tolerance of the depth control machine, and the maximum can reach +/-0.01 millimeter. And the depth control isolation material uses PI film and AD glue with the thickness slightly higher than that of the blind groove, is resistant to high temperature and has the thickness higher than the depth control precision, so that a common depth control precision gong machine can be used for uncovering, and the purchase cost of high-precision equipment in the processing process of the semi-flexible circuit board is saved.

Further, in order to improve the accuracy of the processing of the bending region, so that the depth of the blind groove can be accurately controlled to the position where the blind groove is located, thereby smoothly taking out the isolation material and obtaining a bending region with a smooth and flat surface, in still another embodiment of the present invention, before step 50, the method further includes:

and carrying out positioning marks on the surface of the semi-flexible circuit board corresponding to the position of the blind groove so as to start the action of the depth control gong from the positioning marks.

According to the embodiment of the invention, the depth and the width of the bending region of the semi-flexible circuit board are determined, and the target material layer corresponding to the bottom position of the bending region of the semi-flexible circuit board is determined according to the depth and the width; the semi-flexible circuit board comprises a plurality of circuit layers, wherein the circuit layers are connected with each other through a non-gumming PP (pre-preg) layer; the circuit layer is CCL (Copper Clad Laminate ) or CCL with lower surface copper foil removed, when the circuit layer is CCL, the target material layer is a non-gummosis PP layer, when the circuit layer is CCL with lower surface copper foil removed, the dielectric layer of CCL with lower surface copper foil removed is connected with the non-gummosis PP layer, and the target material layer is the dielectric layer and the non-gummosis PP layer of the lower circuit layer; routing at least one blind groove at the bending area of the target material layer; placing a preset isolation material in the blind groove, sequentially stacking the circuit layers, and then performing gluing treatment to obtain a circuit board to be uncapped; and carrying out depth control gong on the bending area of the circuit board to be uncapped, stopping when gong to the isolating material, uncapping to remove the isolating material, and obtaining the semi-flexible circuit board. Therefore, the problem that the accuracy control is poor and the usability of the semi-flexible circuit board is affected due to uneven surface of the bending region is different from the problem that the bending region is manufactured by the depth control gong in the prior art, and the bending region is provided with at least one blind groove at the bending region position on the target material layer corresponding to the bottom position of the bending region. The circuit layer is obtained by processing the CCL, the CCL dielectric layer has smooth surface and consistent thickness compared with the traditional mechanical depth control, the tolerance of the bending area depends on the CCL tolerance, and the tolerance of the non-depth control machine can reach +/-0.01 mm at most. And the depth control isolation material can use a PI film with a slightly higher thickness than a blind groove, is resistant to high temperature and has a thickness higher than the depth control precision, so that a common depth control precision gong machine can be used for uncovering, and the purchase cost of high-precision equipment in the processing process of a semi-flexible circuit board is saved.

Further, in the embodiment of the present invention, considering that when a plurality of circuit layers are glued, the effect of the original thickness of the circuit layers is affected, in some situations, it may be necessary to remove a copper foil on the lower surface of a part of the circuit layers and then press-fit the copper foil with other circuit layers, which may result in that a material layer corresponding to the bottom position of the bending region may be a non-adhesive PP layer for gluing the circuit layers, or may be a dielectric layer such as FR-4 exposed after the surface copper foil is removed by the CCL, where the dielectric layer is directly connected with the non-adhesive PP layer, and considering that the non-adhesive PP layer has a certain flowability when being pressed, therefore, in the embodiment of the present invention, when the circuit layer is the CCL with the lower surface copper foil removed, the dielectric layer with the lower surface copper foil is connected with the non-adhesive PP layer, and the target material layer is the dielectric layer and the non-adhesive PP layer of the lower circuit layer, so that when the non-adhesive PP layer flows, the non-adhesive PP layer can flow into the dielectric layer of the lower circuit layer through the blind via the groove on the non-adhesive PP layer when flowing, thereby further improving the usability of the circuit board.

The semi-flexible circuit board provided by the further embodiment of the invention is characterized in that the semi-flexible circuit board is manufactured according to the manufacturing method of the semi-flexible circuit board.

In the manufacturing process of the semi-flexible circuit board, the depth and the width of the bending area of the semi-flexible circuit board are determined, and the target material layer corresponding to the bottom position of the bending area of the semi-flexible circuit board is determined according to the depth and the width; the semi-flexible circuit board comprises a plurality of circuit layers, wherein the circuit layers are connected with each other through a non-gumming PP (pre-preg) layer; the circuit layer is CCL (Copper Clad Laminate ) or CCL with lower surface copper foil removed, when the circuit layer is CCL, the target material layer is a non-gummosis PP layer, when the circuit layer is CCL with lower surface copper foil removed, the dielectric layer of CCL with lower surface copper foil removed is connected with the non-gummosis PP layer, and the target material layer is the dielectric layer and the non-gummosis PP layer of the lower circuit layer; routing at least one blind groove at the bending area of the target material layer; placing a preset isolation material in the blind groove, sequentially stacking the circuit layers, and then performing gluing treatment to obtain a circuit board to be uncapped; and carrying out depth control gong on the bending area of the circuit board to be uncapped, stopping when gong to the isolating material, uncapping to remove the isolating material, and obtaining the semi-flexible circuit board. Therefore, the problem that the accuracy control is poor and the usability of the semi-flexible circuit board is affected due to uneven surface of the bending region is different from the problem that the bending region is manufactured by the depth control gong in the prior art, and the bending region is provided with at least one blind groove at the bending region position on the target material layer corresponding to the bottom position of the bending region. The circuit layer is obtained by processing the CCL, the CCL dielectric layer has smooth surface and consistent thickness compared with the traditional mechanical depth control, the tolerance of the bending area depends on the CCL tolerance, and the tolerance of the non-depth control machine can reach +/-0.01 mm at most. And the depth control isolation material can use a PI film with a slightly higher thickness than a blind groove, is resistant to high temperature and has a thickness higher than the depth control precision, so that a common depth control precision gong machine can be used for uncovering, and the purchase cost of high-precision equipment in the processing process of a semi-flexible circuit board is saved.

Further, in the embodiment of the present invention, considering that when a plurality of circuit layers are glued, the effect of the original thickness of the circuit layers is affected, in some situations, it may be necessary to remove a copper foil on the lower surface of a part of the circuit layers and then press-fit the copper foil with other circuit layers, which may result in that a material layer corresponding to the bottom position of the bending region may be a non-adhesive PP layer for gluing the circuit layers, or may be a dielectric layer such as FR-4 exposed after the surface copper foil is removed by the CCL, where the dielectric layer is directly connected with the non-adhesive PP layer, and considering that the non-adhesive PP layer has a certain flowability when being pressed, therefore, in the embodiment of the present invention, when the circuit layer is the CCL with the lower surface copper foil removed, the dielectric layer with the lower surface copper foil is connected with the non-adhesive PP layer, and the target material layer is the dielectric layer and the non-adhesive PP layer of the lower circuit layer, so that when the non-adhesive PP layer flows, the non-adhesive PP layer can flow into the dielectric layer of the lower circuit layer through the blind via the groove on the non-adhesive PP layer when flowing, thereby further improving the usability of the circuit board.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Similarly, it should be appreciated that in the above description of exemplary embodiments of the invention, various features of the embodiments of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. However, the disclosed method should not be construed as reflecting the intention that: i.e., the claimed invention requires more features than are expressly recited in each claim.

Those skilled in the art will appreciate that the modules in the apparatus of the embodiments may be adaptively changed and disposed in one or more apparatuses different from the embodiments. The modules or units or components of the embodiments may be combined into one module or unit or component and they may be divided into a plurality of sub-modules or sub-units or sub-components. Any combination of all features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or units of any method or apparatus so disclosed, may be used in combination, except insofar as at least some of such features and/or processes or units are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The usage of the words first, second and third, etcetera do not indicate any ordering. These words may be interpreted as names. The steps in the above embodiments should not be construed as limiting the order of execution unless specifically stated.

Claims (10)

1. The manufacturing method of the semi-flexible circuit board is characterized by comprising the following steps of:

determining the depth and width of a bending area of the semi-flexible circuit board;

Determining a target material layer corresponding to the bottom position of a bending region of the semi-flexible circuit board according to the depth and the width; the semi-flexible circuit board comprises a plurality of circuit layers, wherein the circuit layers are connected with each other through a non-adhesive PP; the circuit layer is CCL or CCL with the lower surface copper foil removed, when the circuit layer is CCL, the target material layer is a non-gummosis PP layer, when the circuit layer is CCL with the lower surface copper foil removed, the dielectric layer of the CCL with the lower surface copper foil removed is connected with the non-gummosis PP layer, and the target material layer is the dielectric layer and the non-gummosis PP layer of the lower circuit layer;

routing at least one blind groove at the bending area of the target material layer;

placing a preset isolation material in the blind groove, sequentially stacking the circuit layers, and then performing gluing treatment to obtain a circuit board to be uncapped;

and carrying out depth control gong on the bending area of the circuit board to be uncapped, stopping when gong to the isolating material, uncapping to remove the isolating material, and obtaining the semi-flexible circuit board.

2. The method of claim 1, wherein the release material is a polyimide film.

3. The method according to claim 1, wherein determining the target material layer corresponding to the bottom position of the bending region of the semi-flexible circuit board according to the depth and the width comprises:

Determining the number of copper layers contained in a circuit layer below the bottom position of the bending region according to the depth and the thickness information of each layer of material of the semi-flexible circuit board;

when the number of copper layers is an odd number, determining the type of the material layer of the CCL closest to the bending region facing the bending region; the material layer is of a dielectric layer or copper foil;

when the type of the material layer facing the bending area is a medium layer, determining the target material layer as the medium layer and the non-gummosis PP layer of the lower circuit layer;

and when the number of copper layers is even, determining the target material layer as the non-gummosis PP layer.

4. The method of claim 1, wherein routing at least one blind slot at a location of a inflection region of the target material layer, comprises:

when the target material layer is determined to be a dielectric layer and a non-gummosis PP layer of the lower circuit layer, at least one blind groove is formed in a corresponding position on the surface of the lower circuit layer, where the dielectric layer and the non-gummosis PP layer are connected, respectively; the area of each blind groove is smaller than the area of the bottom of the bending area.

5. The method of claim 1, wherein routing at least one blind slot at a location of a inflection region of the target material layer, comprises:

And when the target material layer is determined to be the non-gummosis PP layer, a blind groove with the area equal to the area of the bottom position of the bending area is milled on the non-gummosis PP layer.

6. The method of claim 1, wherein stopping when the bending region of the circuit board to be uncapped is deeply processed, and the isolating material is processed, and uncapping removes the isolating material, so as to obtain a semi-flexible circuit board, wherein the method comprises the following steps:

and carrying out positioning marks on the surface of the semi-flexible circuit board corresponding to the position of the blind groove so as to start the action of the depth control gong from the positioning marks.

7. The method of claim 1, wherein after the preset isolating material is placed in the blind groove, each circuit layer is sequentially stacked and then glued to obtain the circuit board to be uncapped, and the method comprises the following steps:

when the circuit layers are pressed, the dielectric layers of the lower circuit layer and the blind grooves on the non-gummosis PP layer are aligned, so that the non-gummosis PP flows into the blind grooves on the dielectric layers of the lower circuit layer when being pressed to flow.

8. The method of claim 1, wherein after the placing of the predetermined isolation material in the blind slot, the plurality of circuit layers are glued to obtain a circuit board to be uncapped, comprising:

Disposing an adhesive on the release material;

the isolating material is adhesively secured in the blind slot by the adhesive.

9. The method of claim 1, wherein disposing an adhesive on the release material comprises:

obtaining the thickness of the non-gummosis PP layer;

and determining the thickness of the isolating material and the adhesive according to the thickness of the non-gummosis PP layer, so that the total thickness of the isolating material and the adhesive is greater than or equal to the thickness of the non-gummosis PP layer.

10. The semi-flexible circuit board is characterized in that the semi-flexible circuit board is manufactured according to the manufacturing method of the semi-flexible circuit board of any one of claims 1-9.