A selective resin hole protection structure of a rigid-flex printed circuit board

Abstract

The application provides a selective resin hole plugging protection structure of a rigid-flex printed circuit board, which comprises a dry film layer and a rigid-flex printed circuit board provided with a hole to be plugged, a hole not to be plugged and a recessed groove, the dry film layer is attached to the upper and lower sides of the rigid-flex printed circuit board, the dry film layer is provided with a window hole, the window hole corresponds to the position of the hole to be plugged on the rigid-flex printed circuit board, and the thickness of the dry film layer is greater than the depth of the recessed groove. In the application, the dry film layer with a thickness greater than the depth of the recessed groove is attached to the rigid-flex printed circuit board. During operation, the resin only enters the hole to be plugged through the window hole and does not flow into the hole not to be plugged and the recessed groove. During polishing, the resin remaining on the surface of the dry film layer is polished together with the dry film layer. The dry film layer remaining in the recessed groove after polishing can be completely removed through a film stripping process. Finally, the selective resin hole plugging operation of the hole to be plugged is realized, and the technical problem of uneven copper layer thickness of the rigid-flex printed circuit board caused by polishing of the resin remaining in the recessed groove in the prior art is effectively solved.

Description

Technical Field

[0001] This application belongs to the field of printed circuit board technology, specifically relating to a selective resin plugging protection structure for rigid-flex boards. Background Technology

[0002] Currently, the surface of rigid-flex PCBs commonly exhibits unevenness due to height differences (i.e., the presence of recesses). When using traditional selective via plugging processes, resin flows and fills the recesses. During subsequent polishing with ceramic grinding plates, the resin filling the recesses cannot be removed by polishing, resulting in resin residue within the recesses. If the polishing depth is adjusted to remove the resin filling the recesses, the copper surface in the normal position of the rigid-flex PCB will be completely or excessively polished away, causing uneven copper layer thickness on the rigid-flex PCB surface and creating unimaginable difficulties for subsequent circuit etching.

[0003] Meanwhile, the existing resin plugging process requires that the minimum distance between the edge of the unplugged hole (such as the plug hole, which does not need to be filled with resin) and the edge of the hole to be plugged (VIAIN PAD hole, which needs to be filled with resin) is not less than 0.5mm. When the minimum distance between the edge of the unplugged hole and the edge of the hole to be plugged is less than 0.5mm, the existing plugging process will not be able to perform selective plugging.

[0004] In view of this, this application provides a selective resin plugging protection structure for rigid-flex PCBs to solve the above-mentioned technical problems. Utility Model Content

[0005] To address the aforementioned technical problems, this application provides a selective resin plugging protection structure for rigid-flex PCBs, comprising a dry film layer and a rigid-flex PCB with plugged holes, unplugged holes, and recessed grooves. The dry film layer is adhered to the upper and lower sides of the rigid-flex PCB, and has openings that correspond to the positions of plugged holes on the rigid-flex PCB. The thickness of the dry film layer is greater than the depth of the recessed grooves.

[0006] Furthermore, the diameter of the opening is larger than the diameter of the plugging hole.

[0007] Furthermore, the diameter of the opening is 10-50 μm larger than the diameter of the plugging hole.

[0008] Furthermore, the diameter of the opening is 10-30 μm larger than the diameter of the plugging hole.

[0009] Furthermore, the thickness of the dry film layer is 5-10 μm greater than the depth of the recessed groove.

[0010] Compared with existing technologies, the selective resin plugging protection structure for rigid-flex PCBs provided in this application addresses the issue of a dry film layer on the rigid-flex PCB with a thickness greater than the depth of the recessed groove. During selective resin plugging, the resin enters only into the holes to be plugged through the openings, leaving other resin residues on the dry film layer. This prevents resin from flowing into unplugged holes or remaining in the recessed groove. Therefore, during external ceramic grinding, the residual resin on the surface of the dry film layer is ground away, leaving only the dry film layer within the recessed groove. The dry film layer in the recessed groove is then removed using a stripping process. This achieves selective resin plugging of holes on the rigid-flex PCB, effectively solving the technical problem of uneven copper layer thickness on the rigid-flex PCB surface caused by residual resin in the recessed groove during grinding, as described in existing technologies. Furthermore, the presence of the dry film layer facilitates control of the grinding depth of the ceramic grinding plate and allows the dry film layer to be used as a consumable at higher positions on the rigid-flex PCB surface, preventing uneven copper thickness caused by the ceramic grinding process. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of a selective resin plugging protection structure for a rigid-flex plate in some embodiments of this application.

[0012] Explanation of reference numerals in the attached figures:

[0013] 1. Dry film layer, 2. Rigid-flex liner, 21. Hole to be plugged, 22. Hole not plugged, 23. Recessed groove, 3. Window opening. Detailed Implementation

[0014] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0015] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. Conversely, when an element is referred to as being "directly on" another element, there is no intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations. Furthermore, if the embodiments of this utility model involve descriptions of "first," "second," etc., such descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0017] It should be noted that, in the embodiments of this application, [the following text is incomplete and likely refers to a specific implementation or method]. Figure 1 For example, "up" means perpendicular to the paper and "down" means perpendicular to the paper and pointing downwards.

[0018] like Figure 1 As shown, this application provides a selective resin plugging protection structure for a rigid-flex PCB, including a dry film layer 1 and a rigid-flex PCB 2 with plugged holes 21, unplugged holes 22 and recessed grooves 23. The dry film layer 1 is attached to the upper and lower sides of the rigid-flex PCB 2. The dry film layer 1 has a window hole 3, which corresponds to the position of the plugged hole 21 on the rigid-flex PCB 2. The thickness of the dry film layer 1 is greater than the depth of the recessed groove 23.

[0019] In the above embodiment, since the rigid-flex board 2 has a dry film layer 1 with a thickness greater than the depth of the recessed groove 23, during the selective resin plugging operation, the resin will only enter the hole to be plugged 21 through the window hole 3 to fill it, and other resin will only remain on the dry film layer 1 and will not flow into the unplugged hole 22 and the recessed groove 23. Therefore, when the external ceramic grinding plate is polished, the resin remaining on the surface of the dry film layer 1 and the dry film layer 1 are polished away together, leaving only the dry film layer 1 in the recessed groove 23. Then, the dry film layer 1 in the recessed groove 23 is removed by the film removal process, thereby realizing the selective resin plugging operation of the hole to be plugged 21 on the rigid-flex board 2, effectively solving the technical problem of uneven copper layer thickness on the surface of the rigid-flex board caused by the residual resin in the recessed groove during polishing in the prior art. Meanwhile, due to the presence of the dry film layer 1, on the one hand, it is easy to control the grinding depth of the ceramic grinding plate, and on the other hand, the dry film layer 1 can be used as a consumable at a higher position on the surface of the rigid-flex plate 2, avoiding the problem of uneven copper thickness on the surface of the rigid-flex plate 2 caused by the grinding process of the ceramic grinding plate.

[0020] To further understand the working principle and technical effects of this application, the specific process of selectively resin plugging holes in the rigid-flex PCB based on the selective resin plugging protection structure provided in this application is explained below.

[0021] The specific process for selective resin plugging is as follows:

[0022] 1) Place the steel mesh with external openings on the flexible and rigid bonded plate selective resin plugging protection structure;

[0023] 2) Pour resin into the window opening 3. The resin fills the hole to be plugged 21 through the window opening 3. Another part of the resin flows into the gap between the steel mesh and the selective resin plugging protection structure of the flexible and rigid bonding plate 2.

[0024] 3) Use a ceramic grinding plate to grind the upper and lower sides of the rigid-flex plate 2. Since the rigid-flex plate 2 is bonded with a dry film layer 1, the resin will not flow into the groove 23 and the unfilled hole 22 on the rigid-flex plate 2. Therefore, grinding with a ceramic grinding plate can remove the dry film layer 1 and the residual resin on the dry film layer 1.

[0025] 4) The residual dry film layer 1 in the recessed groove 23 can be removed by the film removal process, thereby completing the selective resin plugging operation of the hole 21 to be plugged on the rigid-flex PCB.

[0026] Because the rigid-flex board 2 has a dry film layer 1 with a thickness greater than the depth of the recessed groove 23, during selective resin plugging, the resin will not enter the unplugged holes 22 and the recessed groove 23. Except for the resin filling the holes 21 that need to be plugged, other resin will only remain on the dry film layer 1. When the external ceramic grinding plate is polished, the presence of the dry film layer 1 makes it easy to control the polishing depth. During the polishing process, the resin remaining on the surface of the dry film layer 1 and the dry film layer 1 are polished away together, leaving only the dry film layer 1 in the recessed groove 23. Finally, the dry film layer 1 in the recessed groove 23 can be removed by the film removal process, realizing the selective resin plugging operation of the holes 21 that need to be plugged on the rigid-flex board. This effectively solves the technical problem of uneven copper layer thickness on the rigid-flex board surface caused by residual resin in the recessed groove during polishing in the prior art.

[0027] In some embodiments provided in this application, the diameter of the opening 3 is larger than the diameter of the plugging hole 21.

[0028] In the above embodiments, the diameter of the window opening 3 is 10-50 μm larger than the diameter of the plugging hole 21, preferably 10-30 μm larger. Setting the diameter of the window opening 3 to be larger than the diameter of the plugging hole 21 ensures that the resin fills the plugging hole 21, thus guaranteeing the quality of the final product.

[0029] In some embodiments provided in this application, the thickness of the dry film layer 1 is 5-10 μm greater than the depth of the recessed groove 23.

[0030] In the above embodiments, the thickness of the dry film layer 1 is set to be 5-10 μm greater than the depth of the recessed groove 23. This ensures that the resin will not flow into the recessed groove 23 and remain there, and will not cause too much grinding work to the subsequent ceramic grinding plate, thus improving work efficiency to a certain extent.

[0031] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A selective resin plugging protection structure for rigid-flexible bonded plates, characterized in that, The device includes a dry film layer (1) and a rigid-flexible bonding plate (2) with plugged holes (21), unplugged holes (22) and recessed grooves (23). The dry film layer (1) is attached to the upper and lower sides of the rigid-flexible bonding plate (2). The dry film layer (1) has a window hole (3) which corresponds to the plugged hole (21) on the rigid-flexible bonding plate (2). The thickness of the dry film layer (1) is greater than the depth of the recessed groove (23).

2. The selective resin plugging protection structure for rigid-flexible bonded plates as described in claim 1, characterized in that, The diameter of the opening (3) is larger than the diameter of the plugging hole (21).

3. The selective resin plugging protection structure for rigid-flexible bonded plates as described in claim 2, characterized in that, The aperture of the opening (3) is 10-50 μm larger than that of the plugging hole (21).

4. The selective resin plugging protection structure for rigid-flexible bonded plates as described in claim 3, characterized in that, The aperture of the opening (3) is 10-30 μm larger than that of the plugging hole (21).

5. The selective resin plugging protection structure for rigid-flexible bonded plates as described in claim 1, characterized in that, The thickness of the dry film layer (1) is 5-10 μm greater than the depth of the groove (23).

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