CN112616259B

CN112616259B - Printed circuit board with step plug-in hole and manufacturing method thereof

Info

Publication number: CN112616259B
Application number: CN202110207532.2A
Authority: CN
Inventors: 李清华; 孙洋强; 张仁军; 杨海军
Original assignee: Sichuan Yingchuangli Electronic Technology Co Ltd
Current assignee: Sichuan Yingchuangli Electronic Technology Co Ltd
Priority date: 2021-02-25
Filing date: 2021-02-25
Publication date: 2021-06-08
Anticipated expiration: 2041-02-25
Also published as: CN112616259A

Abstract

The present disclosure provides a printed circuit board with a step plug-in hole and a manufacturing method thereof, wherein the manufacturing method comprises the following steps: fabricating a first core layer, the fabricating the first core layer comprising: drilling a hole at a position of the first core plate layer corresponding to the step plug-in hole to be formed to form a first opening hole penetrating through the first core plate layer; manufacturing a second core plate layer; providing an adhesive layer and drilling holes at the positions, corresponding to the step plug-in holes, on the adhesive layer to form second opening holes which penetrate through the adhesive layer and have slightly larger hole diameters than the step plug-in holes; sequentially laminating the first core plate layer, the bonding layer and the second core plate layer, and performing hot melting, fixing and laminating to form a laminated body, wherein the first opening hole is positioned above the second opening hole and is superposed to form a step plug-in hole; and removing the glue flow in the step plug-in hole by adopting laser to obtain the printed circuit board. The bonding layer is pre-drilled and windowed by the manufacturing method, so that the glue flow in the holes after lamination is effectively reduced, and the quality of the step plug-in holes is ensured.

Description

Printed circuit board with step plug-in hole and manufacturing method thereof

Technical Field

The disclosure relates to the field of printed circuit boards, in particular to a printed circuit board with a step plug-in hole and a manufacturing method thereof.

Background

With the development of electronic products, the multifunctional requirements of products are higher and higher, and the design of the PCB is also changed in order to improve the performance of the products, the assembly density of the products, and reduce the weight and volume of the products. A novel processing technology at present is a step plug-in hole technology, and the step plug-in hole technology is mainly characterized in that components are mounted, and the product integration level is improved or the signal shielding effect is achieved. The main step hole manufacturing method at present is to drill a core layer where the step plug-in hole is located, laminate the core layer with the bonding laminated plate, and drill a hole after lamination to expose a pattern at the bottom of the hole.

The main manufacturing method at the present stage is formed by laser drilling, and the defects mainly comprise: the thickness of the processed core plate is limited, the required circuit below the step plug-in hole cannot be effectively exposed, and the circuit pattern at the bottom of the step plug-in hole is damaged due to overlarge laser energy.

Disclosure of Invention

The present disclosure is directed to addressing at least one of the above-identified deficiencies in the prior art. For example, the present disclosure provides a method for manufacturing a PCB board having a step plug-in hole, which can effectively solve the problem of damage to a circuit under the step plug-in hole due to laser processing.

In order to achieve the above object, in one aspect of the present disclosure, there is provided a method for manufacturing a PCB board having a step interposer hole, including the steps of: fabricating a first core layer, the fabricating the first core layer comprising: drilling a hole at a position of the first core plate layer corresponding to the step plug-in hole to be formed, and forming a first opening hole penetrating through the first core plate layer, wherein the aperture of the first opening hole is the same as that of the step plug-in hole; manufacturing a second core plate layer; providing an adhesive layer, and drilling holes at positions on the adhesive layer corresponding to the step plug-in holes to form second opening holes which penetrate through the adhesive layer and have slightly larger hole diameters than the step plug-in holes; the first core plate layer, the bonding layer and the second core plate layer are sequentially stacked, fixed after hot melting, and then laminated together to form a stacked body, wherein the first opening hole is positioned above the second opening hole and overlapped to form a step plug-in hole; and removing the gummosis in the step plug-in hole by adopting laser, and carrying out outer layer pattern manufacturing to obtain the printed circuit board. Wherein, the step of drilling the position corresponding to the step plug-in hole on the bonding layer comprises: clamping the bonding layer by using two clamping plates, wherein the two clamping plates are superposed with the bonding layer, and the bonding layer is positioned between the two clamping plates; and drilling the clamping plate and the adhesive layer by using a mechanical drilling tool along the direction perpendicular to the adhesive layer, and drilling through the adhesive layer to form a second opening hole on the adhesive layer. Wherein, the step of adopting laser to get rid of the gummosis in the step plug-in components hole can include: and emitting laser towards the step plug-in hole by a laser drilling tool along a direction perpendicular to the printed circuit board so as to remove the gummosis in the step plug-in hole, wherein the laser drilling tool spirally moves from the center of the step plug-in hole to the side wall of the step plug-in hole in a spiral mode so as to remove the residual gum on the bottom and the side wall of the step plug-in hole.

In an exemplary embodiment of the present disclosure, the second opening hole may have a hole diameter 0.4 to 0.6mm larger than that of the step insert hole.

In an exemplary embodiment of the present disclosure, the mechanical drilling tool may be a drilling machine, the rotation speed of the drilling machine may be 5 to 8 ten thousand revolutions per minute, the drill bit progress rate may be 0.8 to 1.2m/min, and the tool retracting rate may be 10 to 14 m/min.

In an exemplary embodiment of the present disclosure, the clamping plate may be an FR4 light plate, the thickness of the clamping plate may be 0.8 to 1.2mm, and the thickness of the adhesive layer may be 0.1 to 0.4 mm.

In an exemplary embodiment of the present disclosure, the first core layer may include a core medium layer and a conductive layer attached on an upper surface and/or a lower surface of the core medium layer, and the fabricating the first core layer may include: cutting, drilling, manufacturing an inner layer circuit and browning.

In one exemplary embodiment of the present disclosure, the inner layer wiring manufacturing step may include: attaching a dry film to the lower surface of the core plate dielectric layer, transferring a designed inner layer circuit pattern to a dry film layer of the inner layer core plate in an exposure mode by adopting an LDI exposure machine for exposure, then developing, melting the dry film which is not exposed, correspondingly etching the exposed circuit pattern through the exposed dry film, and dissolving the copper foil which is not protected by the dry film; and finally, stripping the film, and melting the exposed dry film by using strong alkali to expose the inner layer pattern.

In an exemplary embodiment of the present disclosure, the second core layer may include a core dielectric layer and a conductive layer attached to an upper surface and/or a lower surface of the core dielectric layer, and the step of manufacturing the second core layer includes cutting, inner layer circuit manufacturing, and browning.

In an exemplary embodiment of the present disclosure, the hot melting temperature may be 170-180 ℃, the hot melting time may be 30-60 s, the laminating time is 175-185 min, the temperature rising rate is 1.6-1.8 ℃/min, the curing temperature is 175-185 ℃, and the curing time is in curingThe time is 85-95 min, and the pressure for curing and pressing is 25-35 kg/cm²。

In one exemplary embodiment of the present disclosure, the drill string coefficient of tension may be consistent with the inner layer coefficient of pre-tension when forming the first and second apertures.

The present disclosure also provides in another aspect a printed circuit board having a stepped interposer hole, fabricated using the fabrication method as described above.

Compared with the prior art, the beneficial effects of this disclosure can include:

1) the bonding layer is drilled in advance, so that the step plug-in hole can be directly machined, and the problems that the thickness of a machined core plate is limited, a circuit required below the step plug-in hole cannot be effectively exposed and damaged due to laser drilling machining are effectively solved;

2) the clamping plate is used for clamping the bonding layer and then drilling and windowing, so that the bonding layer can be protected, the problems of gaps and the like at the positions of drilling and windowing are prevented, the press fit and the flow removal glue are influenced, and the quality of the manufactured printed circuit board is influenced;

3) even if the glue flow is large, the glue can be removed thoroughly, the power is low when the laser is used for removing the glue, and the circuit pattern and the base material at the bottom of the step plug-in hole cannot be damaged;

4) the method of circling and moving from the center of the step plug-in hole to the side wall direction of the step plug-in hole can comprehensively and effectively remove the glue at the bottom of the hole and the hole wall, and can avoid the circuit pattern and the base material at the bottom of the hole from being possibly damaged due to repeated ablation at individual positions.

Drawings

Fig. 1 shows a flow chart of a method of manufacturing a printed circuit board having a stepped interposer hole according to an exemplary embodiment of the present disclosure;

FIG. 2 illustrates a cross-sectional view of a first core layer formed in an exemplary embodiment of the present disclosure;

FIG. 3 illustrates a cross-sectional view of drilling a bond coat in an exemplary embodiment of the present disclosure;

FIG. 4 shows a cross-sectional view of the bond layer after drilling;

FIG. 5 illustrates a cross-sectional view of a laminate formed in an exemplary embodiment of the present disclosure;

FIG. 6 is a schematic view showing the step insert of FIG. 5 after removing residual glue from the hole;

FIG. 7 shows a schematic view of the mosquito coil stack-up firing of the present disclosure;

fig. 8 shows a schematic view of a printed circuit board formed after outer layer patterning in an exemplary embodiment of the present disclosure.

Description of reference numerals:

100-a first core board layer, 101-a core board dielectric layer of a first core board, 102-a conductive layer of an upper surface of the first core board, 103-a conductive layer of a lower surface of the first core board, 104-a first opening hole, 200-a bonding layer, 201-a prepreg, 202-a second opening hole, 203-a flow adhesive, 300-a second core board layer, 301-a core board dielectric layer of a second core board, 302-a conductive layer of an upper surface of the second core board, 303-a conductive layer of a lower surface of the second core board, 401-a first clamping plate, 402-a second clamping plate, and 500-a step plug-in hole.

Detailed Description

Hereinafter, a printed circuit board having a step via hole and a method of fabricating the same according to exemplary embodiments of the present disclosure will be described in detail with reference to specific embodiments.

Unless otherwise indicated, the illustrated exemplary embodiments are to be understood as providing exemplary features of varying detail of some ways in which the inventive concepts may be practiced. Thus, unless otherwise specified, features, components, modules, layers, films, panels, regions, and/or aspects and the like (hereinafter, referred to individually or collectively as "elements") of the various embodiments may be otherwise combined, separated, interchanged, and/or rearranged without departing from the inventive concepts.

The use of cross-hatching and/or shading in the drawings is generally provided to clarify the boundaries between adjacent elements. As such, unless otherwise specified, the presence or absence of cross-hatching or shading does not convey or indicate any preference or requirement for a particular material, material property, dimension, proportion, commonality between the illustrated elements, and/or any other characteristic, attribute, property, etc. of the elements. In addition, in the drawings, the size and relative sizes of elements may be exaggerated for clarity and/or descriptive purposes. While example embodiments may be practiced differently, the specific process sequence may be performed in a different order than that described. For example, two processes described consecutively may be performed substantially simultaneously or in reverse order to that described. In addition, like reference numerals denote like elements.

When an element or layer is referred to as being "on," "connected to" or "coupled to" another element or layer, it can be directly on, connected or coupled to the other element or layer or intervening elements or layers may be present. However, when an element or layer is referred to as being "directly on," "directly connected to," or "directly coupled to" another element or layer, there are no intervening elements or layers present. To this end, the term "connected" may refer to physical, electrical, and/or fluid connections, with or without intervening elements. For the purposes of this disclosure, "at least one of X, Y and Z" and "at least one selected from the group consisting of X, Y and Z" can be construed as any combination of two or more of X only, Y only, Z only, or X, Y and Z, such as, for example, XYZ, XYY, YZ, and ZZ. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Although the terms first, second, etc. may be used herein to describe various types of elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another. Thus, a first element discussed below could be termed a second element without departing from the teachings of the disclosure.

Spatially relative terms such as "below … …," "below … …," "below … …," "below," "above … …," "above," "… …," "higher," "side" (e.g., as in "side wall"), and the like, may be used herein for descriptive purposes to describe one element's relationship to another (other) element as illustrated in the figures. Spatially relative terms are intended to encompass different orientations of the device in use, operation, and/or manufacture in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below … …" can encompass both an orientation of above and below. Further, the devices may be otherwise positioned (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, when the terms "comprises" and/or "comprising" and variations thereof are used in this specification, the presence of stated features, integers, steps, operations, elements, components and/or groups thereof are stated but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof. It is also noted that, as used herein, the terms "substantially," "about," and other similar terms are used as approximate terms and not as degree terms, and as such, are used to interpret the inherent degree of deviation of a measured value, calculated value, and/or provided value that would be recognized by one of ordinary skill in the art.

Various exemplary embodiments are described herein with reference to cross-sectional and/or exploded views, which are schematic illustrations of idealized exemplary embodiments and/or intermediate structures. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, example embodiments disclosed herein should not necessarily be construed as limited to the shapes of regions specifically illustrated, but are to include deviations in shapes that result, for example, from manufacturing. In this manner, the regions illustrated in the figures may be schematic in nature and the shapes of the regions may not reflect the actual shape of a region of a device and, as such, are not necessarily intended to be limiting.

Fig. 1 shows a flowchart of a method of manufacturing a printed circuit board having a stepped interposer hole according to an exemplary embodiment of the present disclosure. As shown in fig. 1, in one exemplary embodiment of the present disclosure, a method of manufacturing a printed circuit board having a stepped interposer hole includes the steps of:

and S1, manufacturing a first core plate layer. As shown in fig. 2, a first opening hole 104 is formed through the first core layer 100 by drilling at a position of the first core layer 100 corresponding to a position where the step insert hole is required to be formed.

As shown in fig. 2, the first core layer 100 may include a core dielectric layer 101 and a conductive layer 102 attached to an upper surface and/or a conductive layer 103 attached to a lower surface of the core dielectric layer. The core board dielectric layer can be made of FR-4 material, in particular epoxy resin glass fiber cloth and filled inorganic ceramic material.

Fabricating the first core layer 100 includes: cutting, drilling, manufacturing an inner layer circuit and browning.

Here, the cutting means forming the shape and size of the desired first core board layer 100 by using a cutting machine. For example, the first core layer 100 is formed from a blank having a thickness of 0.25mm (the thickness includes no copper layer thickness, plus 0.32mm of copper layer) and a dimension of 457 x 304 mm.

Wherein the first core layer 100 may be drilled using mechanical drilling to form the desired first opening 104. The aperture of the first opening hole 104 may be the same as that of the step insert hole 500 in fig. 5 to be formed. For example, the first aperture 104 may be a 0.6mm diameter aperture sized hole.

The inner layer circuit manufacturing step may specifically include: attaching a dry film to the lower surface of the core plate dielectric layer, transferring a designed inner layer circuit pattern to a dry film layer of the inner layer core plate in an exposure mode by adopting an LDI exposure machine for exposure, then developing, melting the dry film which is not exposed, correspondingly etching the exposed circuit pattern through the exposed dry film, and dissolving the copper foil which is not protected by the dry film; and finally, stripping the film, and melting the exposed dry film by using strong alkali to expose the inner layer pattern. That is, an inner wiring layer is formed on the lower surface of the first core layer 100. Preferably, vacuum etching may be employed.

Wherein, browning means that a layer of brown cuprous oxide is generated on the circuit layer to enhance the bonding force with the bonding layer 200. And (5) after browning, placing, and waiting for laminating and pressing.

S2, a second core layer 300 is produced. As shown in fig. 5, the second core layers 300 each include a core dielectric layer 301 and a conductive layer 302 attached to an upper surface and/or a conductive layer 303 attached to a lower surface of the core dielectric layer 301, and the step of manufacturing the second core layer 300 may include cutting, inner layer circuit manufacturing, and browning. Here, the specific implementation of the cutting, the inner layer circuit manufacturing, and the browning in the manufacturing of the second core layer 300 may refer to the cutting, the inner layer circuit manufacturing, and the browning in the manufacturing of the first core layer 100. The upper surface of the second core layer 300 forms an inner layer wiring.

And S3, windowing on the adhesive layer to form a second window hole.

An adhesive layer 200 is provided, and as shown in fig. 4, the material used for the adhesive layer 200 is a prepreg material, also called PP. The adhesive layer 200 is cut and windowed.

Wherein, the cutting step can be specifically as follows: the prepreg 201 of a desired size is cut using a PP cutter. For example, the size is 457 x 304 mm.

The windowing may specifically include: holes are drilled in the adhesive layer 200 at positions corresponding to the step insert holes 500 to form second openings 202 penetrating the adhesive layer 200. The second opening hole 202 has a slightly larger aperture than the step insert hole 500. The second opening hole 202 may have a diameter larger than that of the step insert hole 500 by 0.8 to 1.2 mm. In the pressing process, if the aperture of the second opening hole 202 is too large or too small compared with the aperture of the step insert hole 500, and exceeds the range of 0.4-0.6 mm, delamination or excessive glue flow can be caused.

As shown in fig. 3, the adhesive layer 200 may be clamped using two clamping plates (i.e., a first clamping plate 401 and a second clamping plate 402), wherein the first and second clamping plates 401 and 402 and the adhesive layer 200 are stacked, and the adhesive layer 200 is located between the first and second clamping plates 401 and 402; the clamping plate and the adhesive layer 200 are drilled by a mechanical drilling tool in a direction perpendicular to the adhesive layer 200 (direction a in fig. 3), at least through the adhesive layer 200, to form a second opening 202 in the adhesive layer 200, as shown in fig. 4.

It should be noted that, before drilling, the two clamping plates are not drilled in advance, but during drilling, the first clamping plate 401 and the second clamping plate 402 and the adhesive layer 200 are stacked together and then drilled by a mechanical drilling tool. The drilling is performed by ensuring that the adhesive layer 200 is completely drilled through, i.e., the second clamping plate 402 is drilled through, but not necessarily drilled through.

The thickness of the material used for the adhesive layer 200 is generally small, the material has certain flexibility, and the protective clamping plate can prevent the adhesive layer from deforming in the drilling process, so that the adhesive layer 200 is prevented from being broken or holes drilled with irregular shapes. Drilling through the adhesive layer 200 may cause a notch at the windowing position, increasing the glue flow in the subsequent step plug-in hole 500. The adhesive layer 200 is pulled to deform, so that the adhesive layer 200 is uneven on one hand, the quality of the printed circuit board after lamination is affected, and on the other hand, if the drilled hole is not regular and circular, the glue flowing amount on one side of the stepped hole is large after lamination and a hole is formed in the other side due to glue shortage.

The first clamping plate 401 and the second clamping plate 402 can be FR4 light plates, the thickness of the first clamping plate 401 and the second clamping plate 402 can be 0.8-1.2 mm, the thickness of the adhesive layer 200 can be 0.1-0.4 mm, and the thickness of the adhesive layer 200 can be specifically adjusted according to the requirements of products. For example, the thickness of the adhesive layer may be 0.2 mm.

The mechanical drilling tool can be a drilling machine, the rotating speed of the drilling machine can be 5-8 ten thousand revolutions per minute, the speed of progress of a drill can be 0.8-1.2 m/min, and the speed of tool withdrawal can be 10-14 m/min. If the drilling rate and the drill speed rate are too high, defects may be caused in the wall of the hole at the windowing position. The rotational speed, the rate of drill progress and the rate of retraction of the drill while drilling are determined by the thickness of the clamping plate and the bond layer, the thicker the clamping plate and the bond layer the higher the rotational speed will be set, and the lower the rate of drill progress and the rate of retraction.

S4, sequentially stacking the first core layer 100, the adhesive layer 200 and the second core layer 300, then laminating the first core layer 100, the adhesive layer 200 and the second core layer 300 together, and fixing the adhesive layer 200 by riveting after hot melting to form a stacked body (as shown in fig. 5), wherein the first opening hole 104 is located above the second opening hole 202 and stacked to form the step insert hole 500.

In the disclosure, four points can be used for fixing the middle layer lamination hot melting, and the parameters are as follows: the hot melting temperature is 170-180 ℃, the hot melting time is 30-60 s, the laminating time is 175-185 min, the heating rate is 1.6-1.8 ℃/min, the curing temperature is 175-185 ℃, the curing time is 85-95 min, and the pressure of curing and laminating is 25-35 kg/cm². For example, the parameters may be that the hot melting temperature may be 170 ℃, the hot melting time may be 50s, the laminating time may be 180min, the heating rate may be 1.8 ℃/min, the curing temperature may be 180 ℃, the curing time may be 90min, and the pressure for curing and pressing may be 30kg/cm²。

S5, removing the glue flow 203 formed in the step plug hole 500 on the laminated body by laser, and fig. 6 shows the step plug hole 500 after removing the residual glue. Then, outer layer pattern making is carried out to manufacture the printed circuit board.

The laser drilling tool emits laser towards the step plug-in hole 500 along the direction perpendicular to the printed circuit board to remove the gummosis in the step plug-in hole 500, and the laser drilling tool can ablate and break the gummosis in the step plug-in hole 500 by using low-power laser (for example, the power for removing the gummosis is 1/3-1/4 of laser drilling; and the specific laser energy for removing the gummosis is 4-6 mj/time), so that the gummosis can be removed from the step plug-in hole 500 easily (for example, the broken gummosis is blown out or washed out). Wherein the laser drilling tool spirals in a spiral manner from the center of the step insert hole 500 toward the sidewall of the step insert hole 500 to remove the residual glue on the bottom and sidewall of the step insert hole 500. That is, the gummosis can be removed by adopting a mosquito-repellent incense sheet type overlapping and burning method. As shown in fig. 7, the overlapping burning method of the mosquito coil type means that the laser starts from the center position of the step insertion hole 500 and performs the glue removing work like the mosquito coil type coil rotation. The method can effectively remove the residual glue at the bottom and the wall of the hole, and has high efficiency.

Wherein, optional arbitrary laser of only removing adhesive linkage 200 and not damaging substrate and circuit, this disclosure preferably adopts carbon dioxide laser, and the accessible has adjusted working parameter for the gummosis burns out and can not cause the influence to other regions, the accurate circuit figure that exposes step plug-in hole bottom.

Other glue removing methods are adopted, when the glue is removed by using the alkaline potassium permanganate solution, the glue removing amount is small, and the glue cannot be completely removed in a region with large glue overflowing amount; when concentrated sulfuric acid is used for removing glue, the danger is high, and the defects that water washing is needed and the glue removing position is easy to oxidize are caused. Compared with the method for removing glue by using alkaline potassium permanganate solution and concentrated sulfuric acid, the method for removing glue by using laser is simple and convenient to operate and low in danger, and the glue is moved in a spiral mode towards the side wall direction of the step plug-in hole by taking the center of the step plug-in hole as a starting point, so that an ablation area can cover the bottom of the whole step hole, and the situation that two residual glues are not removed completely when the individual positions are not ablated is avoided; meanwhile, the circuit pattern and the base material at the bottom of the hole are prevented from being damaged due to repeated ablation at a certain position; even there is big glue flow volume also can be more thorough get rid of, and the power when the laser removes glue is less, can effectively prevent to cause the harm to circuit figure and the substrate of step plug-in hole bottom.

In addition, the outer pattern formation is the same or similar to the inner pattern formation, and an outer wiring layer is formed on the upper surface of the first core layer 100 and/or the lower surface of the second core layer, and as shown in fig. 8, an outer wiring layer is formed on the conductive layer on the upper surface of the first core layer 100.

It should be noted that steps S1, S2, and S3 are not in strict sequence, and only need to be completed before pressing in step S4.

In addition, the drill string stretch coefficient and the inner layer pre-stretch coefficient may be maintained consistent when forming the first and

second apertures

104, 202. When the engineering data is made before the making process, the tensile coefficient of the drill belt can be made to be consistent with the pre-tensile coefficient of the inner layer, so as to prevent the core board drilling position from being dislocated with the inner and outer layer patterns and the core board drilling position from being dislocated with the bonding layer windowing drilling position.

In the manufacturing method provided in the present exemplary embodiment, a window is formed in advance on the adhesive layer 200, so that the high-power laser (compared to the laser power used for removing the flowing glue in the present disclosure) is not required to process the adhesive layer 200 during the pressing process, which may cause damage to the circuit and the substrate in the step plug-in hole 500, and the amount of the flowing glue in the step plug-in hole 500 preset during the final pressing process may also be reduced, and the glue is removed in a manner of circling and moving from the center of the step plug-in hole as a starting point to the side wall direction of the step plug-in hole, so that the glue is removed thoroughly, and the quality of the step plug-in hole 500 and the manufactured printed circuit board can be greatly ensured.

In another exemplary embodiment of the present disclosure, there is provided a printed circuit board having a stepped interposer hole 500, which is manufactured using the manufacturing method as described above.

The printed circuit board with the stepped interposer 500 and the method of making the same of the present disclosure are further described below by way of detailed examples.

Example (c):

a cutting machine is used to cut the first core plate layer 100 and the second core plate layer 300 with the size of 457 x 304 mm. Drilling a first opening hole 104 with the diameter of 0.6mm in hole size in the first core plate by using a drilling machine; forming a desired inner layer circuit on one side of the first core board layer 100 by using an inner layer dry film method; the inner dry film comprises the working procedures of inner film pasting, exposure, development, inner layer etching and film removing; then, the first core plate layer 100 is browned to remove impurities on the surface, and the bonding force during the pressing operation is increased, and the first core plate layer 100 after the processing is completed is shown in fig. 3. The desired inner layer wiring is formed on one side of the second core layer 300 using the same inner layer dry film method.

Cutting a bonding layer of a PP material with a dimension of 457 × 304mm by using a PP cutting machine, vertically clamping the bonding layer 200 by using a first clamping plate 401 and a second clamping plate 402 as shown in fig. 4, and performing a drilling and windowing operation together with the two clamping plates (such as two FR4 light plates) by using a drilling machine to form a second windowing hole 202 with a diameter of 1.0 mm.

Then, the processed first core layer 100, the PP adhesive layer 200, and the second core layer 300 are sequentially overlapped, and a pressing process is performed, the adhesive layer 200 is hot-melted and then riveted, as shown in fig. 5, to form a laminated body, and the first opening hole 104 and the second opening hole 202 form a step insertion hole 500.

Finally, carbon dioxide laser can be adopted, as shown in figure 7, a mosquito coil sheet type overlapping burning method is used for removing the flowing glue in the preset holes after pressing, as shown in figure 6, and finally the printed circuit board disclosed by the invention is manufactured.

Wherein the hot melting is fixed by four points, the hot melting temperature can be 170 deg.C, the hot melting time can be 50s, the laminating time can be 180min, the heating rate can be 1.8 deg.C/min, the curing temperature can be 180 deg.C, the curing time can be 90min, and the curing and pressing can be 30kg/cm²。

After the processing, if the first core layer 100 and the second core layer 300 are double-sided boards, the circuit fabrication may be performed on the outer surfaces of the first core layer 100 and the second core layer 300, as shown in fig. 8, to finally form a multi-layer printed circuit board.

According to the method, the bonding layer 200 is pre-drilled and windowed, so that the glue flowing amount of the bonding layer 200 which overflows into the holes in the pressing process is effectively reduced, and the quality of the step plug-in hole 500 is ensured; when the bonding layer 200 is windowed, two FR4 light boards are used for protection, so that the problem that gaps occur at the windowing position and the like can be prevented, and the glue flow in the subsequent preset step plug-in hole 500 is increased; the flowing glue in the holes after pressing is preferably CO₂Laser is removed, after working parameters are adjusted, the glue is burnt out in preset time without influencing other areas, and the circuit pattern at the bottom of the step plug-in hole 500 is accurately exposed; the glue is removed by adopting a mosquito-repellent incense sheet type dense overlapping burning method, the method can effectively remove residual glue at the bottom and the hole wall, and the efficiency is high.

Although the present disclosure has been described above in connection with exemplary embodiments and the accompanying drawings, it will be apparent to those of ordinary skill in the art that various modifications may be made to the above-described embodiments without departing from the spirit and scope of the claims.

Claims

1. A manufacturing method of a printed circuit board with a step plug-in hole is characterized by comprising the following steps:

fabricating a first core layer, the fabricating the first core layer comprising: drilling a position, corresponding to the step plug-in hole, of the first core plate layer to be formed to form a first opening hole penetrating through the first core plate layer, wherein the diameter of the first opening hole is the same as that of the step plug-in hole;

manufacturing a second core plate layer;

providing an adhesive layer, drilling holes at positions on the adhesive layer corresponding to the step plug-in holes, and forming second opening holes which penetrate through the adhesive layer and are 0.4-0.6 mm larger than the step plug-in holes, wherein the adhesive layer is made of a prepreg material;

the first core plate layer, the bonding layer and the second core plate layer are sequentially stacked, fixed after hot melting, and then laminated together to form a laminated body, wherein the first windowing hole is positioned above the second windowing hole and is overlapped to form the step plug-in hole; and

removing the gummosis in the step plug-in hole by adopting laser, and carrying out outer layer pattern manufacturing to obtain the printed circuit board;

wherein the step of drilling the bonding layer at a position corresponding to the step insert hole comprises: clamping the bonding layer by using two clamping plates, wherein the two clamping plates are superposed with the bonding layer, and the bonding layer is positioned between the two clamping plates; drilling the clamping plate and the bonding layer by a mechanical drilling tool along a direction perpendicular to the bonding layer, and drilling through the bonding layer to form the second window hole on the bonding layer;

the step of removing the gummosis in the step plug-in hole by adopting laser comprises the following steps: and emitting laser towards the step plug-in hole by a laser drilling tool along a direction perpendicular to the printed circuit board so as to remove the gummosis in the step plug-in hole, wherein the laser drilling tool spirally moves from the center of the step plug-in hole to the direction of the side wall of the step plug-in hole in a spiral manner so as to remove the residual gum on the bottom and the side wall of the step plug-in hole.

2. The method for manufacturing a printed circuit board with a step plug-in hole according to claim 1, wherein the laser glue removal power is 1/4-1/3 of laser drilling; the laser energy of the laser for removing the gummosis is 4-6 mj/time.

3. The method for manufacturing a printed circuit board with a step plug-in hole according to claim 1, wherein the mechanical drilling tool is a drilling machine, the rotating speed of the drilling machine is 5-8 ten thousand revolutions per minute, the speed of progress of a drill is 0.8-1.2 m/min, and the speed of tool withdrawal is 10-14 m/min.

4. The method for manufacturing a printed circuit board having a step plug-in hole according to claim 1, wherein the holding plate is an FR4 optical plate, the thickness of the holding plate is 0.8 to 1.2mm, and the thickness of the adhesive layer is 0.1 to 0.4 mm.

5. The method of claim 1, wherein the first core layer comprises a core dielectric layer and a conductive layer attached to an upper surface and/or a lower surface of the core dielectric layer, and the step-plugging hole-containing printed circuit board comprises: cutting, drilling, manufacturing an inner layer circuit and browning.

6. The method for manufacturing a printed circuit board with a step plug-in hole according to claim 5, wherein the inner layer circuit manufacturing step comprises:

attaching a dry film to the lower surface of the core plate dielectric layer, transferring a designed inner layer circuit pattern to a dry film layer of the inner layer core plate in an exposure mode by adopting an LDI exposure machine for exposure, then developing, melting the dry film which is not exposed, correspondingly etching the exposed circuit pattern through the exposed dry film, and dissolving the copper foil which is not protected by the dry film; and finally, stripping the film, and melting the exposed dry film by using strong alkali to expose the inner layer pattern.

7. The method of claim 1, wherein the second core layers each comprise a core dielectric layer and a conductive layer attached to an upper surface and/or a lower surface of the core dielectric layer, and the step of fabricating the second core layers comprises cutting, inner layer circuit fabrication, and browning.

8. The method for manufacturing a printed circuit board with a step plug-in hole according to claim 1, wherein the hot melting temperature is 170-180 ℃, the hot melting time is 30-60 s, the laminating time is 175-185 min, the heating rate is 1.6-1.8 ℃/min, the curing temperature is 175-185 ℃, the curing time is 85-95 min, and the pressure for curing and pressing is 25-35 kg/cm²。

9. The method of claim 1, wherein the first and second openings are formed with a drill string stretch coefficient consistent with an inner layer pre-stretch coefficient.

10. A printed circuit board comprising a stepped interposer hole, characterized in that it is manufactured using the manufacturing method as claimed in any one of claims 1 to 9.