CN118201249A - Manufacturing method of multilayer layered rigid-flex printed circuit board - Google Patents

Abstract

The invention discloses a manufacturing method of a multilayer layered rigid-flex printed circuit board, which comprises the following steps: manufacturing flexible board layers, attaching covering film layers, wherein the covering film size between the flexible boards is larger than the outer surface covering film size, the circuit patterns on the surface of the flexible boards comprise bonding pads on the outer surface, manufacturing rigid board layers, manufacturing windowed prepregs, arranging and pressing prepregs, and performing large-opening cover processing, surface treatment and forming processing to form rigid-flexible combined boards, wherein the windowed size of each prepreg arranged between the flexible boards is larger than that of the prepregs on other layers; through the structure setting, the processing mode of pressing, uncapping, surface treatment and forming is formed, the problem that the cost of pressing and processing is high after layering surface treatment is avoided, and the problem that common pressing and surface treatment is easy to produce liquid medicine storage, dust storage, sand storage and volcanic ash storage is avoided, and the overall processing method improves the processing efficiency and the processing quality.

Description

Manufacturing method of multilayer layered rigid-flex printed circuit board

Technical Field

The invention relates to the field of circuit board design and processing, in particular to a manufacturing method of a multilayer layered rigid-flex printed circuit board.

Background

The rigid-Flex printed circuit board (Rigid-Flex PCB, also called rigid-Flex printed circuit board or rigid-Flex printed circuit board) has the supporting performance of the rigid board and the bending performance of the flexible board, and has the excellent effects of flexible installation, high reliability and wide application scene, so that the rigid-Flex printed circuit board is applied in more and more fields.

The multi-layer laminated rigid-flex board is characterized in that a plurality of layers of flexible boards exist, one part of the multi-layer flexible boards and the rigid board are laminated to form a rigid board area, the other part of the multi-layer flexible boards are flexible board areas, the flexible boards of the flexible board areas are mutually layered and independent, a connecting mode of 'multiple-in-one' or 'multiple-in-one' is formed, or the interlayer independent conductivity of a circuit is improved, and the mutual interference between layers is reduced.

At present, a multi-layer layered rigid-flex board with bonding pads arranged on the outer surface of a flexible board in a flexible board area can improve the density of interconnection or meet the welding requirements of some special application scenes.

For such a multilayer laminated rigid-flex board, the method for manufacturing the outer surface bonding pad of the flexible board area generally adopts that when the surface circuit patterns of each layer of flexible board are manufactured separately before the rigid-flex board is laminated, the outer surface bonding pad is manufactured, then the flexible board and the rigid board are laminated, and then post-processing is performed.

However, the flexible boards are multi-layered, and the surface treatment and other processing of the outer surface bonding pads are respectively and independently carried out on the flexible boards of all layers, so that the problem of cost increase caused by low processing efficiency is solved, the problem of large expansion and shrinkage effects on the flexible boards of all layers is solved, in addition, the outer surface bonding pads of the flexible boards of all layers are manufactured firstly, and the problems of abrasion, polishing, oxidation and the like of the bonding pads easily occur in the subsequent processing process, so that the quality of the bonding pads is influenced.

Based on the background and the problems, there is a need to provide a method for manufacturing a multilayer laminated rigid-flex board with external surface bonding pads in a flexible board area.

Disclosure of Invention

The invention aims at solving the problems that in the prior art, aiming at a multilayer laminated rigid-flex board with an outer surface bonding pad in a flexible board area, each layer of flexible board is firstly processed independently to form processing of the outer surface bonding pad, then each layer of flexible board is pressed together with a rigid board, and then post-process processing is carried out, the processing efficiency is low, the expansion and shrinkage effect on each layer of flexible board is large, the bonding pad is easy to wear, scratch, oxidize and the like, and the invention provides a manufacturing method of the multilayer laminated rigid-flex board, wherein the rigid-flex board comprises the rigid board area and the flexible board area in the plane direction of the processing board in the processing process, the joint position of the rigid board area and the flexible board area is the rigid-flex joint position, and the outer surface of the flexible board area contains the bonding pad; the processing board comprises a rigid board layer and a flexible board layer which is more than or equal to two layers in the lamination direction, and the plane direction also comprises a forming line, wherein the forming line is a contour edge line of the rigid-flex board.

The manufacturing method comprises the following steps:

s10: taking a flexible copper-clad plate, manufacturing a surface circuit pattern to form the flexible plate layer, and attaching a covering film layer to form a flexible plate layer to be pressed;

a window is formed in the flexible board area range of the covering film layer, part of the surface circuit pattern is exposed, and the bonding pad is formed;

S20: manufacturing and forming the rigid plate layer according to a rigid plate manufacturing method;

s30: taking a prepreg layer, and carrying out unilateral pre-large windowing on the prepreg layer according to the size of the flexible board region to form a windowed prepreg layer;

s40: the method comprises the steps that a rigid plate layer is arranged on an outer layer, a plurality of to-be-pressed flexible plate layers are arranged on an inner layer, a windowing prepreg layer is arranged between the rigid plate layer and the to-be-pressed flexible plate layers and between two adjacent to-be-pressed flexible plate layers, a stacked structure is formed, and lamination is carried out to form a laminated plate;

s50: the laminated board is subjected to uncovering milling, uncovering processing is carried out, and an uncovering structure is formed;

S60: and carrying out surface treatment processing on the cover opening structure, and carrying out forming processing to form the rigid-flex printed circuit board.

Further, the adjacent covering film layers among the plurality of to-be-pressed flexible board layers have a size which extends outwards along the direction of the flexible board area, and the single side is larger than the covering film layer positioned on the outer layer.

Further, the single side is larger than 0.5mm to 5.0mm in size.

Further, the windowed prepreg arranged between two adjacent to-be-pressed flexible board layers is larger than the windowed prepreg arranged between the rigid board layers and the to-be-pressed flexible board layers in a unilateral mode along the windowed dimension of the outwards extending flexible board region.

Further, the single side is larger than 0.2mm to 2.0mm in size.

Optionally, a hot melt adhesive layer is disposed along the edge direction of the flexible board area, and extends towards the direction of the flexible board area and does not exceed the forming line, wherein the hot melt adhesive layer is disposed between two adjacent flexible board layers to be pressed and is measured in the windowing range of the windowing prepreg.

Optionally, the hot melt adhesive layer is an acrylic adhesive layer or an epoxy adhesive layer or a polyimide adhesive layer.

Further, the cover opening milling plate is as follows: performing depth control milling on the edge of the covering film layer which is deep into the rigid plate region to the rigid-flex joint position and the line of the rigid-flex joint position to form a depth control groove; the depth of the depth control groove is from the outer surface to the surface of the covering film layer of the outermost layer; then milling through grooves along the forming line and in the direction of the flexible board area, the distance from the forming line to the edge of the covering film layer, and the distance from the forming line to the edge of the windowing area of the windowing prepreg along the edge of the covering film layer to form through grooves; and the region surrounded by the depth control groove and the through groove forms an uncovering region.

Further, the molding process is as follows: performing forming milling processing on the edge of the flexible board area along the forming line; and milling through grooves in the rest rigid plate area along the forming line.

Further, the forming milling is through cutting processing by using a laser cutting mode.

The technical proposal of the invention firstly stacks the flexible board layers to be pressed and the rigid board layers, sets the single side of the size of the adjacent covering film layer between the flexible board layers to be pressed to be larger than the size of the covering film layer of the outer layer, leads the covering film layer to go deep into the auxiliary processing area of the board edge, gives enough glue overflow allowance for the windowed prepreg, further sets the windowed size of the windowed prepreg between the flexible board layers to be pressed to be larger than the space between the rigid board layers and the flexible board layers to be pressed, forms the glue overflow allowance for the windowed prepreg which enlarges the safety distance (the molding feed distance) between the molding line and the edge of the covering film layer, the effect that the prepreg can effectively bond the covering film layers between the flexible boards with multiple layers and can not overflow glue to the range of the effective area of the rigid-flex board is provided, the processing structural condition that the multilayer laminated rigid-flex board can use the surface bonding pads manufactured after pressing (surface treatment processing of bonding pads) is adopted, meanwhile, the problem that the prepreg overflows glue to the effective area to cause the follow-up difficult uncovering or difficult formation of the multilayer layering effect is prevented, and the problems that liquid medicine, dust and sand are hidden between layers (sand is adopted for pre-blasting treatment and sand is easy to hide between layers) and volcanic ash is hidden between layers (volcanic ash is adopted for pre-treatment and volcanic ash is easy to hide between layers) caused by the fact that the flexible board layers are already subjected to multilayer layering before the surface treatment processing are prevented; further, during uncapping, the mode that the edges of the effective area in the plate and the rigid-flex joint position are used for controlling the depth milling plate to cover the edges of the film layer and the edges of the rigid plate area to penetrate through the milling plate is adopted, so that on one hand, the condition that the effective groove body of the rigid plate layer is removed during uncapping can be provided, the problem that the cover is difficult to uncover due to the fact that the whole depth milling plate is controlled can be prevented, on the other hand, the uncapping area can be formed to extend into the range of the rigid plate area, and the problems that the edges of the rigid-flex joint position are missed to bond and layering and the like can be prevented; further, a manufacturing mode that the windowed prepreg layers are integrally pre-enlarged along the edge direction of the flexible board area and a hot melt adhesive layer is arranged in the windowed prepreg layers between the flexible board layers in a tested mode can be adopted, the hot melt adhesive layer can be used for more effectively and reliably bonding the adjacent covering film layers, and the characteristics of thinner hot melt adhesive layer and higher precision are utilized, so that the processing quality is improved under the effect of the same processing technological process; the whole processing process forms a novel flow processing technology, and a good and complete processing method can be provided for the multilayer layered rigid-flex printed circuit board with the outer surface bonding pads in the flexible board area.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the invention, and that other drawings may be obtained from the structures shown in these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic illustration of a process flow according to an embodiment of the present invention;

FIG. 2 is a schematic cross-sectional view of a stacked structure according to an embodiment of the present invention;

FIG. 3 is a schematic plan view of the section A-A of FIG. 2 according to an embodiment of the present invention;

FIG. 4 is a schematic cross-sectional view of another stacked structure according to an embodiment of the present invention;

FIG. 5 is a schematic plan view of the section A '-A' of FIG. 4 according to an embodiment of the present invention;

FIG. 6 is a schematic cross-sectional view of a laminated board formed according to an embodiment of the present invention;

FIG. 7 is a schematic cross-sectional view of a laminated board formed according to an embodiment of the present invention;

FIG. 8 is a schematic plan view of a structure of a milling plate for forming an opening cover according to an embodiment of the present invention;

FIG. 9 is a schematic plan view of a structure for forming an opening cover according to an embodiment of the present invention;

FIG. 10 is a schematic plan view of the section B-B of FIG. 9 according to the embodiment of the present invention;

FIG. 11 is a schematic plan view of a forming plate according to an embodiment of the present invention;

FIG. 12 is a schematic plan view of a rigid-flex printed circuit board according to an embodiment of the present invention;

fig. 13 is a schematic cross-sectional structure of a rigid-flex printed circuit board according to an embodiment of the present invention.

Reference numerals illustrate:

The achievement of the object, functional features and advantages of the present invention will be further described with reference to the drawings in connection with the embodiments.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, based on the embodiments of the invention, which are apparent to those of ordinary skill in the art without inventive faculty, are intended to be within the scope of the invention.

It should be noted that all directional indicators (such as up, down, left, right, front, and rear … …) in the embodiments of the present invention are merely used to explain the relative positional relationship, movement, etc. between the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.

Furthermore, descriptions such as those referred to as "first," "second," and the like, are provided for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implying an order of magnitude of the indicated technical features in the present disclosure. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

Referring to fig. 1, fig. 1 is a schematic process flow diagram of an embodiment of the invention.

The manufacturing method of the multi-layer laminated rigid-flex printed circuit board provided in the embodiment is manufactured according to the process flow in fig. 1, and the steps will be described in detail below.

Referring to fig. 2 and 3, fig. 2 is a schematic cross-sectional structure of a stacked structure according to an embodiment of the present invention; fig. 3 is a schematic plan view of the section A-A of fig. 2 according to the embodiment of the present invention.

In the method for manufacturing the multilayer laminated rigid-flex printed circuit board of the embodiment, the rigid-flex printed circuit board comprises a rigid board area 100 and a flexible board area 200 in the plane direction of a processing board in the processing process, the joint position of the rigid board area 100 and the flexible board area 200 is a rigid-flex joint position 100J, and the outer surface of the flexible board area 200 comprises a bonding pad 410; the processing board comprises a rigid board layer (a first rigid board layer 1410 and a second rigid board layer 1420 shown in fig. 2) and more than or equal to two flexible board layers in the lamination direction, the plane direction also comprises a forming line 100C, and the forming line 100C is a contour edge line of the rigid-flex board;

Step S10:

taking a flexible copper clad laminate, manufacturing a surface circuit pattern, attaching a cover film layer, attaching a first cover film layer 1110 and a second cover film layer 1120 to the first flexible board layer 110 in fig. 2, and attaching a third cover film layer 1210 and a fourth cover film layer 1220 to the second flexible board layer 120 to form a flexible board layer to be pressed; and windows are formed in the flexible board area 200 of the covering film layer, and part of the surface circuit patterns are exposed to form the bonding pads 410.

In this embodiment, the adjacent cover film layers (the second cover film layer 1120 and the third cover film layer 1210 shown in fig. 2) between the plurality of flexible board layers have a size extending outward in the direction of the flexible board region 200, and have a single side larger than the cover film layers (the first cover film layer 1110 and the fourth cover film layer 1220 shown in fig. 2) located on the outer layer; the size of the single side larger than the single side is 0.5mm to 5.0mm.

By increasing the size of the inner layer covering film layer, the extension to the auxiliary area of the board edge (the area of the board edge, which is provided with auxiliary tool patterns distributed in the processing process and is not reserved on the finished product) is formed, so that a larger space is provided for the subsequent prepreg gumming and bonding, and the surface layer covering film layer does not need to be particularly provided with the increased size, so that an internal expansion adhesion area is formed; the size is not excessively increased, otherwise, the waste of the plate is caused, and the cost is increased.

Step S20:

forming the rigid plate layers (e.g., the first rigid plate layer 1410 and the second rigid plate layer 1420 in fig. 2) according to a rigid plate manufacturing method; the surface of the rigid plate layer is provided with a copper layer, and the copper layer is manufactured later to form an outer surface circuit pattern.

Step S30:

Taking a prepreg layer, and performing unilateral pre-windowing on the prepreg layer according to the size of the flexible board region 200 to form a windowed prepreg layer (such as a first windowed prepreg 1310, a second windowed prepreg 1320 and a third windowed prepreg 1330 in fig. 2); the prepreg layer plays roles of forming a whole between bonding layers, filling a line gap and controlling the whole thickness.

In this embodiment, the windowed prepreg (the first windowed prepreg 1310 in fig. 2) disposed between two adjacent flexible board layers 200 has a windowed size extending outward in the direction of the flexible board region 200, and the windowed prepreg (the second windowed prepreg 1320 and the third windowed prepreg 1330 in fig. 2) disposed between the rigid board layer and the flexible board layer has a single side larger than the windowed size; the size of the single side larger than the single side is 0.2mm to 2.0mm.

In this way, the differential size setting of the covering film layers is matched, that is, the prepreg with enlarged opening is arranged between the covering film layers with larger size, and as the final finished product needs to form multiple layers of independent layering between the flexible boards, in the lamination process, the prepreg with larger opening can form the adhesion effect on the edge of the covering film layer with larger size within the range of the preset size of the covering film layer with larger size, and the adhesion area cannot go deep (gummosis) to the effective area (the area reserved by the final finished product) due to the preset size, that is, the first opening prepreg 1310 forms the adhesion to the edges of the second covering film layer 1120 and the third covering film layer 1210, and does not gummosis to the range of the forming line 100C, so that the interlayer adhesion of the multiple layers of the flexible board layers in the processing is formed, and after the forming processing forms the finished board, the adhesion area is cut off, so that the necessary structural condition is provided for the subsequent integrated surface treatment.

Referring to fig. 4 and 5, fig. 4 is a schematic cross-sectional structure diagram of another stacked structure according to an embodiment of the present invention; fig. 5 is a schematic plan view of the section a '-a' of fig. 4 according to an embodiment of the present invention.

In an alternative embodiment, a hot melt adhesive layer 300 is disposed along the edge direction of the flexible board area, and the hot melt adhesive layer 300 extends toward the flexible board area 200 and does not exceed the molding line 100C, when measured in the window region of the window prepreg (as shown in fig. 4) disposed between two adjacent flexible board layers; the hot melt adhesive layer 300 is an acrylic adhesive layer or an epoxy adhesive layer or a polyimide adhesive layer; the thickness of the hot melt adhesive layer may be generally set to be 10 μm to be equal to the thickness of the corresponding prepreg layer.

In this embodiment, the bonding between the cover film layers is formed by using the high-temperature adhesion property and the high-precision processing property of the hot-melt adhesive layer 300 in a manner of providing the hot-melt adhesive layer 300, so that the interlayer adhesion of the multi-layer flexible board layer in the processing process with the same effect as the above is achieved, and the effect that the adhesion area is milled after the finished board is formed by molding processing is achieved; when the hot melt adhesive layer 300 is adopted, the prepregs of each layer do not need to be windowed with different sizes, the originally designed windowed size can be used, or the unified and pre-large windowed size is adopted, and the covering film layer does not need to be set with different sizes; because of the original design, a molding reserved interval of 0.2mm to 1.0mm exists between the prepreg windowing and the molding line 100C, and the hot melt adhesive layer 300 can be arranged in the interval, and the width can be 0.1mm to 0.9mm according to the situation; the hot melt adhesive layer 300 is arranged, so that the processing precision can be effectively improved, and the influence of gummosis errors of prepregs on products can be reduced; and the method of setting the hot melt adhesive layer 300 is adopted, and the subsequent processing mode is the same as the mode of distinguishing and windowing by adopting the size of the prepreg.

Referring to fig. 6 and 7, fig. 6 is a schematic cross-sectional structure of a laminated board according to an embodiment of the invention; fig. 7 is a schematic cross-sectional view of a laminated board according to an embodiment of the present invention.

Step S40:

The laminated board 20 is formed by disposing the rigid board layer on the outer layer, disposing the plurality of flexible board layers on the inner layer, disposing the windowed prepreg layer between the rigid board layer and the flexible board layer, and between two adjacent flexible board layers, forming a laminated structure (laminated structure 10 as shown in fig. 2 or another laminated structure 10A as shown in fig. 4), and laminating.

And after stacking and pressing, the interlayer adhesive effect is formed between the cover films with larger sizes through the gumming (or the arranged hot melt adhesive layer 300) of the prepreg.

Referring to fig. 8, 9 and 10, fig. 8 is a schematic plan view of a structure of a milling plate for forming an opening cover according to an embodiment of the present invention; FIG. 9 is a schematic plan view of a structure for forming an opening cover according to an embodiment of the present invention; fig. 10 is a schematic plan view of a section B-B of fig. 9 according to an embodiment of the present invention.

Step S50:

The laminate is subjected to face milling to form a face milling plate structure 30 shown in fig. 8, and face milling is performed to form a face opening structure 40 shown in fig. 9.

The uncapping milling plate is as follows: performing depth control milling along the line extending to the edge of the covering film layer of the rigid plate region 100 to the rigid-flex joint 100J and the rigid-flex joint 100J to form a depth control groove 310; the depth of the depth control groove 310 is from the outer surface to the surface of the outermost covering film layer (i.e., the depths of the first rigid plate 1410 and the second rigid plate 1420 on both sides respectively); then milling through grooves along the forming line 100C, and facing the direction of the flexible board area, the distance from the edge of the covering film layer to the edge of the windowing area of the windowed prepreg along the edge of the covering film layer to form through grooves 320; the region surrounded by the depth control groove 310 and the through groove 320 forms an uncapping region 30K.

Because the glue layer adheres to the covering film layers between the flexible board layers, when the surface treatment is performed on the welding disc, the multilayer flexible board needs to be guaranteed to be in an integral state, and the welding disc on the outer surface of the flexible board needs to be exposed outside, so that the flexible board is firstly subjected to large uncovering processing, namely, the original uncovering area range (namely, the finished flexible board area of the rigid-flex board of the final finished product) is enlarged, the enlargement is performed in the length direction and the width direction, as shown in fig. 8, the right and left ends of the front view in the figure are in the width direction, the upper and lower ends are in the length direction, the width direction is enlarged to be out of the range of the adhesion area, and the edges of the covering film layers with smaller sizes (namely, the edges of the first covering film layer 1110 and the fourth covering film layer 1220 in fig. 2) are not exceeded, and then the rigid board layer and the prepreg cannot be uncovered due to adhesion, so that the length direction needs to extend from the rigid board to the rigid-flex joint position 100J to the direction of the rigid board, and the problem that layering is caused by the infirm adhesion at the corner position of the rigid-flex joint position is prevented, and otherwise, the length direction does not exceed the size of the extending into the extending film layer.

In this step, as shown in fig. 8, the upper and lower molding edges of the rigid plate region are processed, and can be used as supports for the processing plate in the next step.

Referring to fig. 11, 12 and 13, fig. 11 is a schematic plan view of a forming board according to an embodiment of the present invention; FIG. 12 is a schematic plan view of a rigid-flex printed circuit board according to an embodiment of the present invention; fig. 13 is a schematic cross-sectional structure of a rigid-flex printed circuit board according to an embodiment of the present invention.

Step S60:

the cover-opening structure is subjected to surface treatment to form a surface treatment pad 410B as shown in fig. 11, and is subjected to forming to form a forming through groove 510 as shown in fig. 11, and the processing board forms a forming processing board 50, and the rigid-flex board 60 is formed after the whole processing.

The forming processing is as follows: forming, milling and processing the edge of the flexible board area 200 along the forming line 100C; and milling through grooves of the rest of the rigid plate area 100 along a forming line to form forming through grooves 510; and the forming milling is through cutting processing by using a laser cutting mode.

Because the edge area of the multi-layer flexible board is bonded by the prepreg (or the hot melt adhesive layer), the multi-layer flexible board forms a whole, and the problems of liquid medicine storage, dust storage, sand storage or volcanic ash storage between layers can not occur during surface treatment processing, so that the hidden danger of processing the multi-layer layered rigid-flex board is effectively solved; after the surface treatment is finished, the appearance of the finished product is processed, the flexible plate area can be processed by laser cutting, and the rigid plate area can be formed by mechanical milling.

In the actual processing and application processes, different circuit board products have different designs, processing and application situations, and the drawings in this embodiment are used only as an implementation process for illustrating this embodiment, and do not represent the dimension ratio of the actual product or the drawing in which the dimension ratio is enlarged in equal proportion according to the actual situation.

The foregoing is only the preferred embodiments of the present invention, and not the limitation of the scope of the present invention, and all the equivalent structural changes made by the description of the present invention and the accompanying drawings or the direct/indirect application in other related technical fields are included in the scope of the present invention.

Claims (10)

1. The manufacturing method of the multilayer layered rigid-flex printed circuit board comprises the steps that the rigid-flex printed circuit board comprises a rigid board area and a flexible board area in the plane direction of a processing board in the processing process, the joint position of the rigid board area and the flexible board area is a rigid-flex joint position, and the outer surface of the flexible board area comprises a bonding pad; the processing board comprises a rigid board layer and a flexible board layer which are more than or equal to two layers in the lamination direction, and the plane direction also comprises a forming line, wherein the forming line is a contour edge line of the rigid-flex board;

the manufacturing method is characterized by comprising the following steps of:

s10: taking a flexible copper-clad plate, manufacturing a surface circuit pattern to form the flexible plate layer, and attaching a covering film layer to form a flexible plate layer to be pressed;

a window is formed in the flexible board area range of the covering film layer, part of the surface circuit pattern is exposed, and the bonding pad is formed;

S20: manufacturing and forming the rigid plate layer according to a rigid plate manufacturing method;

s30: taking a prepreg layer, and carrying out unilateral pre-large windowing on the prepreg layer according to the size of the flexible board region to form a windowed prepreg layer;

s40: the method comprises the steps that a rigid plate layer is arranged on an outer layer, a plurality of to-be-pressed flexible plate layers are arranged on an inner layer, a windowing prepreg layer is arranged between the rigid plate layer and the to-be-pressed flexible plate layers and between two adjacent to-be-pressed flexible plate layers, a stacked structure is formed, and lamination is carried out to form a laminated plate;

s50: the laminated board is subjected to uncovering milling, uncovering processing is carried out, and an uncovering structure is formed;

S60: and carrying out surface treatment processing on the cover opening structure, and carrying out forming processing to form the rigid-flex printed circuit board.

2. The method for manufacturing a multi-layered rigid-flex board according to claim 1, wherein,

And the adjacent covering film layers among the plurality of to-be-pressed flexible plate layers are larger than the covering film layers positioned on the outer layer on one side along the outward extending dimension of the flexible plate area.

3. The method for manufacturing a multi-layered flex-rigid board according to claim 2, wherein the single side is larger than 0.5mm to 5.0mm.

4. The method for manufacturing a multilayer laminated rigid-flex printed circuit board according to claim 2, wherein the windowed prepreg arranged between two adjacent flexible board layers to be laminated has a windowed size extending outwards along the direction of the flexible board region, and a single side is larger than the windowed size of the windowed prepreg arranged between the rigid board layer and the flexible board layers to be laminated.

5. The method of manufacturing a laminated rigid-flex board according to claim 4, wherein said single side is 0.2mm to 2.0mm in size.

6. The method for manufacturing a multilayer laminated rigid-flex board according to claim 1, wherein a hot melt adhesive layer is arranged along the edge direction of the flexible board area and extends towards the flexible board area and does not exceed the forming line, wherein the hot melt adhesive layer is arranged in the windowing range of the windowed prepreg between two adjacent flexible board layers to be pressed.

7. The method of claim 6, wherein the hot-melt adhesive layer is an acrylic adhesive layer, an epoxy adhesive layer, or a polyimide adhesive layer.

8. The method for manufacturing the multilayer laminated rigid-flex printed circuit board according to claim 4 or 6, wherein the cover-opening milling plate is as follows:

performing depth control milling on the edge of the covering film layer which is deep into the rigid plate region to the rigid-flex joint position and the line of the rigid-flex joint position to form a depth control groove; the depth of the depth control groove is from the outer surface to the surface of the covering film layer of the outermost layer;

then milling through grooves along the forming line and in the direction of the flexible board area, the distance from the forming line to the edge of the covering film layer, and the distance from the forming line to the edge of the windowing area of the windowing prepreg along the edge of the covering film layer to form through grooves;

And the region surrounded by the depth control groove and the through groove forms an uncovering region.

9. The method for manufacturing a multilayer laminated rigid-flex board according to claim 4 or 6, wherein the forming process is as follows:

performing forming milling processing on the edge of the flexible board area along the forming line;

and milling through grooves in the rest rigid plate area along the forming line.

10. The method of claim 9, wherein the forming milling is through cutting by laser cutting.