A forming and manufacturing method of a rigid-flexible board and a rigid-flexible board

Abstract

The present invention discloses a method for forming and manufacturing a rigid-flexible board, the method comprising: providing a rigid-flexible board to be formed, the rigid-flexible board to be formed comprising a rigid board area, a flexible board area, and a rigid-flexible bonding area; performing a milling process of a first preset circuit on the flexible board area; performing a depth-controlled milling process of a second preset circuit on the rigid-flexible bonding area; performing a laser ablation process of a third preset circuit on the flexible board area; and performing a forming milling process of a fourth preset circuit on the rigid-flexible board to be formed, so as to obtain the rigid-flexible board. The present invention performs a milling process and a laser ablation process on the flexible board area of ​​the rigid-flexible board respectively, and its processing method has high precision and can effectively solve the problem of excessive burrs at the corners of the bonding area of ​​the rigid-flexible board, thereby improving product quality.

Description

Technical Field

[0001] The present invention relates to the field of circuit boards, and in particular to a forming and manufacturing method of a rigid-flexible board and the rigid-flexible board. Background Art

[0002] Rigid-Flex PCBs (rigid-flex PCBs) are circuit boards that consist of both a flexible board (flexible area) and a rigid board (rigid area). Similar to conventional multilayer PCBs, rigid-flex PCBs utilize multiple layers laminated together to form a multilayer board. The final forming process typically involves milling. Because the dielectric layer of a flexible PCB is typically made of polyimide, it offers greater toughness, greater material inertness, and superior flexural properties compared to the epoxy resin-fiberglass sheet used in rigid PCBs.

[0003] During the rigid-flexible board forming process, the milling cutter cuts the circuit board. For rigid-flexible boards, since the flexible area has more dielectric layers (that is, more polyimide layers), the corners where the rigid board and the flexible board meet will have a large contact area with the milling cutter during the forming process, which will produce more burrs, affect the processing quality, and even cause problems such as pulling and tearing.

[0004] Currently, the burr problem is generally improved by adjusting the milling cutter parameters (such as milling cutter travel speed, milling cutter rotation speed, etc.). However, the machining method of the milling cutter and the processing method of direct contact with the circuit board determine the characteristics of its processing results. Therefore, it is difficult to improve the burr problem by adjusting the milling cutter parameters.

[0005] Based on the above problems, it is necessary to provide a molding and manufacturing method for a rigid-flexible board to solve the problem of excessive molding burrs at the corners where the rigid board and the flexible board of the rigid-flexible board are combined. Summary of the Invention

[0006] The main purpose of the present invention is to propose a method for forming and manufacturing a rigid-flexible board, which aims to solve the technical problem in the prior art that when a milling cutter is used to form a rigid-flexible board, the burrs at the corners where the rigid board and the flexible board of the rigid-flexible board are joined are too large.

[0007] To achieve the above objectives, the present invention provides a method for forming and manufacturing a rigid-flexible board, the method comprising:

[0008] Providing a rigid-flexible board to be formed, wherein the rigid-flexible board to be formed includes a rigid board area, a flexible board area, and a rigid-flexible bonding area;

[0009] Performing a first preset line milling process on the flexible plate area;

[0010] Performing a second depth-controlled milling process of a preset route on the rigid-flexible junction area;

[0011] Performing a third laser ablation process of a preset circuit on the flexible board area;

[0012] The rigid-flexible board to be formed is subjected to a fourth preset circuit forming milling process to obtain a rigid-flexible board.

[0013] Furthermore, the flexible board area includes a reserved position, and the reserved position is located on a side of the flexible board area and close to the rigid board area.

[0014] Furthermore, the width of the reserved space is in the range of 0.5 mm to 1.5 mm, and the length of the reserved space is less than or equal to 1 / 3 of the length of the flexible board area.

[0015] Furthermore, the first preset circuit covers the edge of the flexible board area and avoids the reserved position.

[0016] Furthermore, the second preset line covers the rigid-flexible bonding area and intersects with the first preset line.

[0017] Furthermore, the third preset line covers the reserved position and is 0.1 mm to 0.15 mm away from the flexible board area.

[0018] Furthermore, the third preset route includes a horizontal preset path and a longitudinal preset path.

[0019] Furthermore, the third preset route is a spiral ablation path or an "S"-shaped ablation path.

[0020] Furthermore, the manufacturing method further includes manufacturing a pure glue area in the reserved position, and the manufacturing method of the pure glue area is:

[0021] During the process of making the inner layer pattern of the flexible board, the circuit copper layer of the reserved position is etched to form a blank pattern position;

[0022] Filling the blank pattern position with pure glue;

[0023] The rigid board, the flexible board and the cover film layer are subjected to a layout and pressing process according to the stacked structure to form the rigid-flexible board to be formed with the pure glue area.

[0024] To achieve the above-mentioned object, the present invention proposes a rigid-flexible board, which is manufactured by the above-mentioned molding and manufacturing method.

[0025] In the technical solution of the present invention, the forming and manufacturing method of the rigid-flexible composite board provided by the present invention performs the milling groove process and the laser ablation process on the flexible board area of ​​the rigid-flexible composite board respectively. The processing method has high precision and can effectively solve the problem of excessive burrs at the corners of the rigid-flexible composite board bonding area, thereby improving product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0027] Figure 1 A schematic diagram of the process flow of a method for forming and manufacturing a rigid-flex board according to the present invention;

[0028] Figure 2 This is a structural schematic diagram of a rigid-flex board according to the present invention;

[0029] Figure 3 This is a schematic structural diagram of a rigid-flex board to be formed according to the present invention;

[0030] Figure 4 This is a schematic structural diagram of a first preset circuit to be formed on a rigid-flex board of the present invention;

[0031] Figure 5 for Figure 4 A magnified schematic diagram of area A in the middle;

[0032] Figure 6 This is a schematic structural diagram of a second preset circuit to be formed on a rigid-flex board of the present invention;

[0033] Figure 7 for Figure 6 A magnified schematic diagram of area B in the middle;

[0034] Figure 8 This is a schematic structural diagram of a third preset circuit to be formed on a rigid-flex board of the present invention;

[0035] Figure 9 for Figure 8 Enlarged schematic diagram of the middle C area;

[0036] Figure 10 Schematic diagram of the structure of the spiral ablation path of the present invention;

[0037] Figure 11 This is a schematic structural diagram of the "S"-shaped ablation path of the present invention;

[0038] Figure 12 This is a schematic structural diagram of the fourth preset circuit to be formed on a rigid-flex board of the present invention;

[0039] Figure 13 for Figure 12 Enlarged schematic diagram of region D in the middle;

[0040] Figure 14 This is a structural schematic diagram of another embodiment of a rigid-flex board to be formed according to the present invention;

[0041] Figure 15 for Figure 14 Schematic diagram of the cross-sectional structure of EE.

[0042] Description of Figure Numbers:

[0043] Label name Label name 100 Rigid-Flex PCB 120 Flexible board area 110 Rigid plate area 121 Flexible plate area flexure 101 Board edge support area 122 Flexible board area joint edge 102 First time preset line 123 Reserved seat 103 Second preset line 124 Circuit copper layer 104 The third preset line 125 Covering film layer 105 Fourth preset line 1241 Pure rubber area 130 Rigid-flexible junction area 1041 Horizontal preset path / / 1042 Vertical preset path

[0044] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0045] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0046] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0047] In addition, the terms "first," "second," and so on, used in this disclosure are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referenced. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this disclosure, "plurality" means at least two, such as two or three, unless otherwise specifically defined.

[0048] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0049] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0050] In the prior art, the typical manufacturing process for ordinary circuit boards includes: cutting; inner layer pattern processing (pre-processing micro-etching, laminating the photosensitive layer, exposure, development, etching, and stripping); layout and lamination process; drilling process; electroplating (copper deposition, board electroplating); outer layer pattern processing; pattern electroplating process; solder mask process; surface treatment process; molding process; electrical testing process; FQC appearance inspection process; packaging process; and finally shipping. The rigid-flex PCB manufacturing method of this embodiment focuses on the molding process.

[0051] Please refer to Figure 1 and Figure 2 , Figure 1 A schematic diagram of the process flow of a method for forming and manufacturing a rigid-flex board according to the present invention; Figure 2 The figure is a structural schematic diagram of a rigid-flex board according to the present invention.

[0052] like Figure 2 As shown, the rigid-flex board 100 of this embodiment is composed of Figure 1 The rigid-flex board 100 includes a rigid board area 110 , a flexible board area 120 and a rigid-flex board area 130 .

[0053] Please also refer to Figures 1 to 13 The specific steps of the molding and manufacturing method of a rigid-flexible board of the present invention include:

[0054] Step S10: providing a rigid-flexible board to be formed, wherein the rigid-flexible board to be formed includes a rigid board area, a flexible board area, and a rigid-flexible bonding area.

[0055] In this embodiment, a rigid-flexible board to be formed is provided. The rigid-flexible board to be formed has undergone all the pre-processes of conventional rigid-flexible board production, such as cutting; inner layer graphic process processing; typesetting and pressing process processing; drilling process processing; electroplating process processing; outer layer graphic process processing; graphic electroplating process processing; solder mask process processing and surface treatment process processing, etc., which are not listed here one by one.

[0056] like Figure 3 As shown, the rigid-flexible board 100 to be formed not only includes a rigid board area 110, a flexible board area 120 and a rigid-flexible board area 130 where the rigid board area 110 and the flexible board area 120 intersect, but also includes a board edge support area 101 for supporting processing, wherein the rigid board area 110, the flexible board area 120 and the rigid-flexible board area 130 are all located inside the board edge support area 101. For the sake of subsequent processing understanding, the side processing area of ​​the flexible board area 120 is further divided into a flexible board area flexural folding edge 121 and a flexible board area combining edge 122, that is, the side processing area of ​​the flexible board area 120 includes the flexible board area flexural folding edge 121 and the flexible board area combining edge 122. The flexible panel area flexing edge 121 is located in the middle of the side processing area of ​​the flexible panel area 120, and the flexible panel area joining edge 122 is located in the end area of ​​the side processing area of ​​the flexible panel area 120 close to the rigid panel area 110. That is, the flexible panel area flexing edge 121 and the flexible panel area joining edge 122 are located on the panel edge support area 101.

[0057] Step S20: performing a first preset circuit milling process on the flexible board area.

[0058] The flexible board area 120 in this embodiment includes a reserved space 123, which is located on the side of the flexible board area 120 and close to the rigid board area 110. Specifically, the reserved space 123 is located in the side processing area of ​​the flexible board area 120, that is, within the flexible board area joint edge 122, and the area of ​​the reserved space 123 is smaller than the area of ​​the flexible board area joint edge 122.

[0059] The width of the reserved space 123 is in the range of 0.5 mm to 1.5 mm, and the length of the reserved space 123 is less than or equal to 1 / 3 of the length of the flexible board area 120. Specifically, the shape of the reserved space 123 is irregular or triangular, and the width varies from small to large from one end to the other.

[0060] like Figure 4 and Figure 5As shown, the flexible board area 120 undergoes a first edge milling process for the preset circuit 102. The first preset circuit 102 covers the edge of the flexible board area 120 and avoids the reserved position 123. Specifically, the first preset circuit 102 is located in the side processing area of ​​the flexible board area 120 and avoids the reserved position 123. That is, the reserved position 123 does not undergo the edge milling process, preparing for the subsequent laser ablation process. The edge milling process is a conventional groove milling process and is not described in detail here.

[0061] Step S30: performing a second depth-controlled milling process of a preset route on the rigid-flexible interface.

[0062] like Figure 6 and Figure 7 As shown, the rigid-flexible bonding area 130 is subjected to a second depth-controlled milling process of the preset circuit 103, so that the rigid board located above the flexible board area 120 of the rigid-flexible bonding board is uncovered. The second preset circuit 103 covers the rigid-flexible bonding area and intersects with the first preset circuit 102, that is, the second preset circuit 103 extends along the rigid-flexible bonding area 130 to the first preset circuit 102 and intersects with the first preset circuit 102, thereby completely uncovering the rigid board located above the flexible board area 120 of the rigid-flexible bonding board. The depth-controlled milling process is a conventional milling process and will not be described in detail here.

[0063] Step S40: performing a third laser ablation process of a preset circuit on the flexible circuit area.

[0064] like Figure 8 and Figure 9 As shown, the third laser ablation process of the preset circuit 104 is performed on the flexible board area 120. The third preset circuit 104 covers the reserved position 123 and is 0.1mm-0.15mm away from the flexible board area. Specifically, the third preset circuit 104 is on the reserved position 123 in the side processing area of ​​the flexible board area 120 and is 0.1mm-0.15mm away from the edge of the formed flexible board area 120. Since the third laser ablation process is performed, the laser burns at a high temperature, which affects the polyimide layer of the flexible board area 120 and causes it to curl. Therefore, the third preset circuit 104 needs to be 0.1mm-0.15mm away from the flexible board area.

[0065] Specifically, since the reserved position 123 is irregular in shape, the reserved position 123 can be divided into different areas. In this embodiment, the third preset line 104 includes a horizontal preset path 1041 and a vertical preset path 1042. The vertical preset path 1042 is arranged close to the side of the flexible board area 120, and the horizontal preset path 1041 is arranged away from the side of the flexible board area 120. The horizontal preset path 1041 and the vertical preset path 1042 are combined to form the reserved position 123.

[0066] The third preset circuit 104 is a spiral ablation path or an "S" type ablation path. Specifically, the horizontal preset path 1041 and the longitudinal preset path 1042 are both spiral ablation paths or "S" type ablation paths. Figure 10 , “S” type ablation path see Figure 11 .

[0067] In this embodiment, the key laser parameters for the laser ablation process include: using a UV laser, wherein the UV laser light source is 355nm, the UV power is 12W to 20W, the focused spot diameter is 10μm to 20μm, the focus control accuracy is 0.003mm to 0.007mm, and the alignment accuracy is 3μm to 10μm. Furthermore, using laser ablation, the reserved position 123 can be ablated on both sides, divided into two ablations, that is, first ablation from the front side and then ablation from the back side. This avoids the accumulation of carbon powder after ablation from a single side, which affects the repeated ablation effect, and prevents the formation of slopes during ablation.

[0068] Furthermore, if the inner layer of the reserved position 123 contains a copper layer (i.e., a circuit layer), the number of laser ablation times in the laser ablation process is 10 to 20 times. In actual applications, it can be ablated 5 to 10 times from the front side and then ablated 5 to 10 times from the back side.

[0069] In this embodiment, the laser ablation path (i.e., the third preset circuit 104) of the laser ablation process may adopt the following path manner:

[0070] (1) The longitudinal preset path 1042 and the transverse preset path 1041 are separate paths.

[0071] (2) If a spiral ablation path is used for the longitudinal preset path 1042 and the transverse preset path 1041, the spiral ablation path is specifically a circle drawn from the outer end to the inner end and gradually converges, which is more conducive to the sufficiency and uniformity of ablation.

[0072] (3) If the longitudinal preset path 1042 and the transverse preset path 1042 adopt an “S”-shaped ablation path, the “S”-shaped ablation path specifically adopts an “S”-shaped ablation route from one end to the other end.

[0073] Step S50: performing a fourth preset circuit forming milling process on the rigid-flexible board to be formed, so as to obtain a rigid-flexible board.

[0074] like Figure 12 and Figure 13 As shown, the rigid-flex board to be formed is subjected to a forming milling process for the fourth preset circuit 105 to obtain the rigid-flex board 100. The fourth preset circuit 105 is located around the steel plate area 110 and the flexible plate area 120 of the rigid-flex board, and part of the fourth preset circuit 105 overlaps with the first preset circuit 102 and the third preset circuit 104. The forming milling process is a conventional milling process and is not described in detail here.

[0075] In this embodiment, the one-time forming milling process is divided into two times (i.e., first milling the edge groove of the flexible board, and finally milling the entire board), which can provide an effective processing basis guarantee for the uncovering processing and laser trimming processing, avoiding the burrs at the corners caused by direct formation, and the pulling and impact on the corners caused by controlled depth milling; and the uncovering processing is combined with the laser trimming processing, and the burrs at the corners are effectively removed by laser ablation of the corners, and the forming accuracy of the flexible board is improved; multiple milling and laser processing form a characteristic sequential processing flow, which can effectively solve the problem of excessive forming burrs at the corners of the rigid board and the flexible board of the rigid-flexible board.

[0076] Please also refer to Figures 14 and 15 This embodiment is substantially the same as the above embodiment, except that the reserved position 123 of this embodiment includes forming a pure glue area 1231 at the reserved position 123, wherein the steps of the method for forming the pure glue area 1231 are as follows:

[0077] Step 11: During the process of making the inner layer pattern of the flexible circuit board, the circuit copper layer of the reserved position is etched to form a blank pattern position.

[0078] In this embodiment, since the inner layer of the flexible circuit board needs to be patterned, the copper layer in the reserved area is etched to form a blank pattern area during the patterning process. In the case of a thick copper layer in the flexible circuit board, laser ablation is not easy to ablate the copper layer. Therefore, the reserved copper layer is replaced with a pure plastic area to facilitate laser ablation.

[0079] Specifically, the flexible circuit board includes a circuit copper layer 124 and a cover film layer 125. When the inner circuit pattern of the flexible circuit board is produced, the reserved position set at the corner where the rigid board and the flexible circuit board meet is simultaneously etched to etch away the copper layer 1241 in the reserved position 123. That is, when the inner circuit pattern of the flexible circuit board is processed, the copper layer pattern of the flexible circuit copper layer 124 at the reserved position 123 is also etched away. The copper layer pattern at the reserved position 123 is along the corner edge of the rigid-flexible junction. The etched copper area of ​​the reserved position 123 is the same size as the reserved position 123, that is, the width of the etched copper area is 0.5mm-1.5mm, and the length of the etched copper area does not exceed 1 / 3 of the length of the flexible circuit board area.

[0080] Step 12: Fill the blank pattern position with pure glue.

[0081] The blank pattern position is filled with pure glue, and the copper layer area of ​​the etched reserved position 123 is supplemented or filled with pure glue. The size of the filled pure glue is generally 0.1mm-0.3mm smaller than the single side of the etched copper area. Such a setting can give the pure glue a certain glue flow space to prevent problems such as pressing voids or glue overflow.

[0082] Step 13: The rigid board, the flexible board, and the cover film layer are subjected to a layout and pressing process according to the laminated structure to form a rigid-flexible board to be formed with the pure glue area 1231 .

[0083] The laminated structure of a rigid-flex PCB consists of a stack of rigid boards, flexible boards, and a cover film. These layers are laminated and laid out to form a rigid-flex PCB with a pure adhesive area. For subsequent laser ablation processing, the areas designated 123 are free of copper and contain only pure adhesive, making the laser ablation process easier to complete.

[0084] In this embodiment, the copper layer circuit of the reserved position 123 is replaced with pure glue, which reduces the number of laser ablation processing times and saves time.

[0085] To sum up, in the technical solution of the present invention, the forming and manufacturing method of the rigid-flexible composite board provided by the present invention performs the milling groove process and the laser ablation process on the flexible board area of ​​the rigid-flexible composite board respectively. The processing method has high precision and can effectively solve the problem of excessive burrs at the corners of the bonding area of ​​the rigid-flexible composite board, thereby improving product quality.

[0086] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for forming a rigid-flex board, characterized in that: The molding method comprises: Providing a rigid-flexible board to be formed, wherein the rigid-flexible board to be formed includes a rigid board area, a flexible board area, and a rigid-flexible bonding area; The flexible board area includes a reserved position, which is located at a side of the flexible board area and close to the rigid board area; the length of the reserved position is less than or equal to 1 / 3 of the length of the flexible board area; Performing a first preset line milling process on the flexible plate area; The first preset line covers the edge of the flexible board area and avoids the reserved position; Performing a second depth-controlled milling process of a preset route on the rigid-flexible junction area; The second preset line covers the rigid-flexible combination area and intersects with the first preset line; Performing a third laser ablation process of a preset circuit on the flexible board area; The third preset line covers the reserved position and is 0.1mm-0.15mm away from the flexible board area; The rigid-flexible board to be formed is subjected to a fourth preset circuit forming milling process to obtain a rigid-flexible board.

2. The production method according to claim 1, wherein: The width of the reserved position ranges from 0.5 mm to 1.5 mm.

3. The production method according to claim 1, wherein The third preset route includes a horizontal preset path and a vertical preset path.

4. The production method according to claim 3, wherein: The third preset route is a spiral ablation path or an "S"-shaped ablation path.

5. The production method according to claim 1 or 2, characterized in that: The manufacturing method further includes manufacturing a pure glue area in the reserved position, and the manufacturing method of the pure glue area is: During the process of making the inner layer pattern of the flexible board, the circuit copper layer of the reserved position is etched to form a blank pattern position; Filling the blank pattern position with pure glue; The rigid board, the flexible board and the cover film layer are subjected to a layout and pressing process according to the stacked structure to form the rigid-flexible board to be formed with the pure glue area.

6. A rigid-flex board, characterized in that: The rigid-flex board is manufactured by the molding method according to any one of claims 1 to 5.

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