PCB with semi-through blind hole
By setting up pre-drilling holes in the first plate structure of the PCB board and using PP layer laminated and pressed connections, combining the method of pre-setting copper pads and depositing copper layers at the bottom of the blind hole, the semi-blind-hole PCB board is solved. The problems of hole depth consistency, bottom flatness and coating bonding are achieved, and the semi-pass blind-hole PCB board with high precision and stable quality.
Patent Information
- Application Number
- CN202323577806.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-27
- Publication Date
- 2025-02-18
- Estimated Expiration
- 2033-12-27
AI Technical Summary
In the prior art, when making semi-blind-hole PCB boards, it is difficult to control the consistency of hole depth, resulting in large tolerances; the bottom of the blind hole is uneven, which affects the accuracy; it is difficult to process semi-blind-holes with shallow depth in thin media structures, affecting the Signal; and the coating bonding force is poor during copper plating, and the coating peeling is prone to occur.
By setting pre-drilled holes in the first plate structure of the PCB board and using PP layers to stack and press and connect them to form semi-blind holes; pre-set copper pads at the bottom of the blind holes to ensure that the bottom is flat; on the thin plate layer When processing semi-blind holes, adjust the core plate and PP thickness to control the hole depth; deposit copper layer at the bottom of the blind holes to improve the coating bonding force.
The semi-blind holes are achieved with high accuracy, flat bottom and stable quality, avoiding the difficulty in ensuring the accuracy of traditional deep-controlled back drills, improving the reliability and signal quality of PCB boards, and reducing the risk of plating peeling.
Smart Images
Figure CN222509645U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of PCB board production, in particular to a PCB board with half-through blind holes. Background Art
[0002] The step groove is designed with a special half-through blind hole. In addition to the conduction function, this type of half-through blind hole also requires plug-in welding, so the product processing accuracy and reliability requirements are high. Since PP (acrylic resin overflow) will occur during the PCB board pressing process, the corresponding back-drilling hole is obtained by depth-controlled back drilling after pressing, and then the half-through blind hole connection is achieved by copper plating. The traditional PCB production process with half-through blind holes can be seen Figure 1 , see Figure 2 Schematic diagram and Figure 3 Schematic diagram of a half-through blind hole obtained by depth-controlled back drilling in the prior art.
[0003] However, the existing semi-through blind holes obtained by depth-controlled back drilling still have the following technical problems:
[0004] When depth-controlled back drilling is used to process half-through blind holes, the internal connection layer must be completely drilled through. The depth consistency is difficult to control, resulting in large tolerance problems in the half-through blind holes of existing half-through blind hole PCB boards.
[0005] The bottom of the semi-through blind hole processed by controlled depth back drilling is V-shaped due to the drill bit, so the bottom of the blind hole is also V-shaped. The bottom of the existing semi-through blind hole is uneven, which affects the accuracy of the PCB board.
[0006] When controlled depth back drilling is used to process half-through blind holes, the internal connection layer must be completely drilled through, and there are requirements for the dielectric thickness of the adjacent layer, which is generally required to be ≥0.25mm. However, since the existing half-through blind holes are obtained by controlled depth back drilling, it is difficult to obtain shallower half-through blind holes in a thin dielectric structure of ≤0.10mm, which results in thick board layers and affects PCB signals.
[0007] After controlled depth back drilling, the bottom of the blind hole is the substrate dielectric layer. During copper electroplating, it is directly deposited on the substrate surface, which has poor bonding strength with the plating and is prone to plating peeling. Summary of the invention
[0008] The utility model aims to avoid the shortcomings of the prior art and provide a PCB board with a semi-through blind hole, wherein the semi-through blind hole of the PCB board has the advantages of high precision, flat bottom and stable quality.
[0009] In order to achieve the above purpose, the utility model provides the following technical solutions:
[0010] A PCB board with a half-through blind hole is provided, comprising:
[0011] A first board layer structure, wherein the first board layer structure is composed of at least one first core board, each first core board is provided with a pre-drilled hole, adjacent first core boards are connected by stacking and pressing PP layers with pre-drilled holes, and the pre-drilled holes on each first core board and the pre-drilled holes on each PP layer are stacked to form a semi-through blind hole;
[0012] The second board layer structure is composed of at least one second core board, the second board layer structure is located below the first board layer structure, and the first board layer structure and the second board layer structure are connected by stacking PP layers with pre-drilled holes.
[0013] In some embodiments, the diameter width of the copper pad is 0.1-0.3 mm larger than the diameter width of the half-through blind hole, and the first board layer is pressed onto the periphery of the copper pad.
[0014] In some embodiments, the hole depth of the half-through blind hole is ≤0.1 mm.
[0015] In some embodiments, the pre-drilled holes have the same diameter.
[0016] In some embodiments, the diameter of the pre-drilled hole is enlarged by 0.05-0.2 mm.
[0017] In some embodiments, a copper layer is deposited on the inner sidewall of the half-through blind via and the surface of the copper pad.
[0018] In some embodiments, the first board layer structure includes two first core panels, the second board layer includes one second core panel, and adjacent first core panels are connected via a PP layer.
[0019] The beneficial effects of the PCB board with half-through blind holes of the utility model are as follows:
[0020] (1) The utility model discloses a PCB board with a semi-through blind hole, wherein the semi-through blind hole is formed by stacking pre-drilled holes in the first board core layer. By adjusting the thickness of the core board and the PP according to the depth requirement of the semi-through blind hole, the depth of the blind hole can be accurately controlled and the tolerance requirement of ±0.05 mm can be met. There is no need for depth-controlled back drilling, thus avoiding the problem of difficult to ensure the accuracy of traditional hole depth back drilling, and overcoming the reliability risks such as poor connection caused by shallow back drilling or short circuit caused by deep back drilling.
[0021] (2) The PCB board with a semi-through blind hole of the utility model has a preset copper pad at the bottom of the semi-through blind hole. The copper pad has a flat surface, which ensures the flatness of the bottom of the semi-through blind hole, avoids the problem of a V-shaped bottom surface caused by traditional back drilling, and effectively ensures the quality of the semi-through blind hole.
[0022] (3) The PCB board with half-through blind holes of the utility model has a copper soldering pad at the bottom of the half-through hole. The copper soldering pad has a strong bonding force with the plating layer, thereby avoiding the risk of plating peeling. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 It is a schematic diagram of the production process of PCB boards in the prior art.
[0024] Figure 2 It is a schematic diagram of preparing a semi-through blind hole by controlled depth back drilling in the prior art.
[0025] Figure 3 It is a schematic diagram of a half-through blind hole obtained by depth-controlled back drilling in the prior art.
[0026] Figure 4 It is a working state diagram of the first plate layer structure, the second plate layer structure, the half-through blind hole and the soldering copper plate of the utility model.
[0027] Reference numerals:
[0028] 1. first board layer structure, 11. first core board, 12. PP layer;
[0029] 2. second board layer structure, 21. second core board;
[0030] 3. Copper pad;
[0031] 4. Half-through blind hole. DETAILED DESCRIPTION
[0032] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.
[0033] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "the" and "the" used in the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.
[0034] It should be understood that although the terms "first", "second", "third", etc. may be used to describe various information in the present invention, this information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present invention, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.
[0035] The step groove is designed with a special half-through blind hole. In addition to the conduction function, this type of half-through blind hole also requires plug-in welding, so the product processing accuracy and reliability requirements are high. Since PP (acrylic resin overflow) will occur during the PCB board pressing process, the corresponding back-drilling hole is obtained by depth-controlled back drilling after pressing, and then the half-through blind hole connection is achieved by copper plating. The traditional PCB production process with half-through blind holes can be seen Figure 1 , see Figure 2 Schematic diagram and Figure 3 Schematic diagram of a half-through blind hole obtained by depth-controlled back drilling in the prior art.
[0036] However, the existing semi-through blind holes obtained by depth-controlled back drilling still have the following technical problems:
[0037] When depth-controlled back drilling is used to process half-through blind holes, the internal connection layer must be completely drilled through. The depth consistency is difficult to control, resulting in large tolerance problems in the half-through blind holes of existing half-through blind hole PCB boards.
[0038] The bottom of the semi-through blind hole processed by controlled depth back drilling is V-shaped due to the drill bit, so the bottom of the blind hole is also V-shaped. The bottom of the existing semi-through blind hole is uneven, which affects the accuracy of the PCB board.
[0039] When controlled depth back drilling is used to process half-through blind holes, the internal connection layer must be completely drilled through, and there are requirements for the dielectric thickness of the adjacent layer, which is generally required to be ≥0.25mm. However, since the existing half-through blind holes are obtained by controlled depth back drilling, it is difficult to obtain shallower half-through blind holes in a thin dielectric structure of ≤0.10mm, which results in thick board layers and affects PCB signals.
[0040] After controlled depth back drilling, the bottom of the blind hole is the substrate dielectric layer. During copper electroplating, it is directly deposited on the substrate surface, which has poor bonding strength with the plating layer and is prone to plating peeling. In this regard, the following embodiments are disclosed:
[0041] Example 1
[0042] See also Figure 4 This embodiment discloses a PCB board with a half-through blind hole, comprising:
[0043] A first plate layer structure 1, wherein the first plate layer structure 1 is composed of at least one first core plate 11, each first core plate 11 is provided with a pre-drilled hole, adjacent first core plates 11 are connected by stacking and pressing together through a PP layer 12 provided with a pre-drilled hole, and the pre-drilled holes on each first core plate 11 and the pre-drilled holes on each PP layer are stacked to form a semi-through blind hole 4;
[0044] Specifically, there are a plurality of first core plates 11 , each of which is provided with a pre-drilled hole. The plurality of first core plates 11 are stacked, and a plurality of first core plates 11 are stacked to form a semi-through blind hole 4 .
[0045] A second plate layer structure 2, wherein the second plate layer structure 2 is composed of at least one second core plate 21, and the second plate layer structure 2 is located below the first plate layer structure 1, and the first plate layer structure 1 and the second plate layer structure 2 are connected by stacking PP layers with pre-drilled holes;
[0046] A copper pad 3, which is disposed on the surface of the second board layer structure 2 and located at the bottom of the half-through blind hole 4;
[0047] Specifically, the copper pad 3 is located on the surface of the second core board 21 at the top.
[0048] Specifically, the copper pad 3 has a relatively flat surface, which avoids the V-shaped problem at the bottom of the blind hole, thereby ensuring that the bottom surface of the blind hole is a flat surface.
[0049] In this embodiment, the diameter width of the copper pad 3 is 0.1-0.3 mm larger than the diameter width of the half-through blind hole 4 , preferably 0.2 mm, and the first board layer structure 1 is pressed against the periphery of the copper pad 3 .
[0050] Increasing the diameter width of the copper pad 3 helps to fill the bottom surface of the entire half-through blind hole 4 and makes it easier for the first board layer structure 1 to press the copper pad 3. At the same time, 0.2 mm can ensure a good pressing effect and minimize the cost of the copper pad 3.
[0051] In this embodiment, the hole depth of the semi-through blind hole 4 is ≤0.1 mm.
[0052] Since the semi-through blind hole 4 of the present embodiment is obtained by stacking pre-drilled holes, there is no need for depth-controlled back drilling, and there is no clear requirement for the thickness of the board layer. The semi-through blind hole 4 can be processed on a thin board layer of ≤0.10 mm, so that the hole depth of the semi-through blind hole 4 is ≤0.1 mm, thereby improving the accuracy of the PCB. In addition, since the semi-through blind hole 4 is obtained by stacking pre-drilled holes, the depth of the semi-through blind hole 4 can be accurately controlled, thereby improving the accuracy of the semi-through blind hole.
[0053] In this embodiment, the diameters of the pre-drilled holes are the same.
[0054] Since the pre-drilled holes on each board layer have the same diameter, a straight half-through blind hole 4 can be obtained after the board layers are stacked.
[0055] In this embodiment, the diameter of the pre-drilled hole is enlarged by 0.05-0.2 mm, preferably 0.1 mm.
[0056] For example, assuming that the diameter width of the half-through blind hole 4 is 0.6, the radius of the half-through blind hole 4 is 0.6, and the enlarged radius is 0.05 mm. At this time, a 0.7 mm drill bit must be used to process the first core plate 11.
[0057] In practical applications, through a limited number of experiments, the effects of the four hole diameters of the semi-through blind holes on the PP flow rate are obtained as shown in Table 1.
[0058] Table 1
[0059]
[0060] It can be seen from Table 1 that when the pre-drilled hole diameter of the half-through blind hole 4 of the first board layer structure 1 is increased by 0.1 mm, the half-through blind hole 4 is not filled with PP glue flow, no voids appear at the edge of the half-through blind hole 4, and there is slight glue flow at the edge of the half-through blind hole 4 ≤ 0.2 mm. It can be seen that when the pre-drilled hole diameter of the half-through blind hole 4 of the first board layer structure 1 is increased by 0.1 mm, the PP glue flow can be minimized to fill the half-through blind hole 4, and there is less slight glue flow at the edge of the half-through blind hole 4, thereby achieving the effect of saving glue flow and no voids appear.
[0061] In this embodiment, the pre-drilled holes of the PP layer 12 include: according to the diameter width of the pre-drilled holes of the first core board 11 , the diameter width of the pre-drilled holes of the PP layer 12 is increased by 0.1 mm.
[0062] In this embodiment, a copper layer is deposited on the inner side wall of the half-through blind hole 4 and the surface of the copper pad 3 .
[0063] The copper layer is directly deposited on the copper pad 3 preset at the bottom of the blind hole, which can effectively improve the bonding of the copper plating and prevent the plating from peeling off easily in the half-through blind hole 4.
[0064] In this embodiment, the first board layer structure 1 includes two first core boards 11 , the second board layer includes one second core board 21 , and adjacent first core boards 11 and second core boards 21 are connected via a PP layer 12 .
[0065] The number and thickness of the first core plates 11 can be adjusted according to actual conditions. The first plate layer structure 1 and the second plate layer structure 2 of this embodiment can obtain relatively thin plate layers.
[0066] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.
[0067] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.
[0068] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.
[0069] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.
[0070] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.
Claims
1. A PCB board with half-through blind holes, characterized in that: include: A first board layer structure, wherein the first board layer structure is composed of at least one first core board, each first core board is provided with a pre-drilled hole, adjacent first core boards are connected by laminating and pressing PP layers provided with pre-drilled holes, and the pre-drilled holes on each first core board and the pre-drilled holes on each PP layer are stacked to form a semi-through blind hole; A second plate layer structure, wherein the second plate layer structure is composed of at least one second core plate, the second plate layer structure is located below the first plate layer structure, and the first plate layer structure and the second plate layer structure are connected by stacking PP layers with pre-drilled holes; A copper pad is arranged on the surface of the second board layer structure and is located at the bottom of the half-through blind hole.
2. The PCB board with half-through blind holes according to claim 1, characterized in that: The diameter width of the copper pad is 0.1 to 0.3 mm larger than the diameter width of the half-through blind hole, and the first board layer structure is pressed against the periphery of the copper pad.
3. The PCB board with half-through blind holes according to claim 1, characterized in that: The hole depth of the half-through blind hole is ≤0.1 mm.
4. The PCB board with half-through blind holes according to claim 1, characterized in that: The pre-drilled holes have the same diameter.
5. The PCB board with half-through blind holes according to claim 1, characterized in that: The diameter of the pre-drilled hole is enlarged by 0.05 to 0.2 mm.
6. The PCB board with half-through blind holes according to claim 1, characterized in that: A copper layer is deposited on the inner side wall of the half-through blind hole and the surface of the copper pad.
7. The PCB board with half-through blind holes according to claim 1, characterized in that: The first board layer structure includes two first core boards, the second board layer includes a second core board, and adjacent first core boards are connected via a PP layer.