Method and device for manufacturing high-voltage-resistant large-current automobile PCB (printed circuit board)

Abstract

The embodiment of the invention relates to a method and a device for manufacturing a high-voltage-resistant large-current automobile PCB (printed circuit board), and the method comprises the steps: when an ultra-large blind hole of the automobile PCB is manufactured, after a hole is drilled to a certain depth through mechanical depth detection, the hole is drilled and ablated to an inner target layer through laser, and the machining and manufacturing of the ultra-large blind hole are realized. The problems that an ultra-large blind hole cannot be machined through laser drilling and the thickness is not enough due to the fact that mechanical drilling penetrates through more dielectric layers are solved, and the requirement that the ultra-large blind hole is resistant to high voltage and large current is met.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of PCB manufacturing, and in particular to a method and device for manufacturing a high-voltage and high-current automotive PCB board. Background Art

[0002] With the rapid development of new energy vehicles, 800V high-voltage platforms are increasingly appearing in more and more models. Higher voltages will appear when the vehicle is charging. At the same time, the acceleration performance of new energy vehicles per 100 kilometers is also constantly improving, and high currents may also appear during driving. Therefore, automotive PCB boards need to be able to withstand high voltages and large currents. There is a type of automotive board that requires ultra-large blind holes with large apertures and thick dielectric layers. Using conventional laser drilling methods, the laser energy is insufficient and it is impossible to drill through very thick dielectric layers. Using the controlled depth drilling method, the layer to be drilled needs to be drilled through, and the dielectric layer between the layer that cannot be drilled through and the layer to be drilled through becomes thinner and the voltage resistance is weakened. At the same time, the hole depth increases, resulting in an increase in the thickness-to-diameter ratio and increased difficulty in electroplating. Summary of the invention

[0003] In view of the above problems, the embodiments of the present invention provide a method and device for manufacturing a high-voltage and high-current automotive PCB board, which is used to solve the problem that the laser energy is insufficient and a thick dielectric layer cannot be drilled through in the existing conventional laser drilling method. When the controlled depth drilling method is used, the layer to be drilled through needs to be drilled through, and the dielectric layer between the non-drillable layer and the layer to be drilled through becomes thinner and the voltage resistance capacity is weakened. At the same time, the hole depth increases, resulting in an increase in the thickness-to-diameter ratio and an increase in the difficulty of electroplating.

[0004] According to one aspect of an embodiment of the present invention, a method for manufacturing a high-voltage and high-current automotive PCB board is provided, the method comprising: Pressing, obtaining a core board, and pressing a plurality of the core boards together to form a PCB board; Mechanical drilling, drilling a first blind hole on the PCB board by controlled depth drilling; Laser drilling, forming a second blind hole by laser ablation at the bottom of the first blind hole; Plasma cleaning, cleaning the second blind hole by plasma; PTH+ electroplating, electroplating the PCB board with a high aspect ratio electroplating solution to form a first electroplating layer on the surface of the blind hole; Resin plugging: the second blind hole after electroplating is plugged with resin by means of partial plugging of empty aluminum sheet; Cover plated hole: After the plug hole is plugged, the second blind hole is electroplated for the second time to complete the blind hole production.

[0005] In some optional embodiments, in the mechanical drilling, A flat bottom drill bit is used to drill a first blind hole from the first board of the PCB board according to a first preset depth, wherein the depth tolerance of the controlled depth drilling is + / -0.1 mm.

[0006] In some optional embodiments, in the laser drilling, Laser ablation is performed at a second preset depth at the bottom of the first blind hole by a circumferential ablation method.

[0007] In some optional embodiments, the pressing specifically includes: The core plates are aligned by fusion + rivet method, and the inter-layer alignment is measured after the core plates are aligned, so that the layer deviation tolerance of the core plates is + / -0.1mm; the expansion and contraction coefficients of all core plates are measured by target cutting and grinding lines, and the drill belt is adjusted according to the average value of the expansion and contraction coefficients.

[0008] In some optional embodiments, the plasma cleaning further includes: The first slice detection is used to confirm whether the bottom of the second blind hole has a positive etch back greater than 2 um. If yes, proceed to the next step; otherwise, laser drilling is performed again.

[0009] In some optional embodiments, the PTH+ electroplating further includes: The second section test is used to confirm whether the copper of the second blind hole is greater than or equal to 18um. If so, proceed to the next step, otherwise, perform a second PTH+ electroplating, wherein brushing and micro-etching are required in the second PTH+ electroplating.

[0010] In some optional embodiments, the resin plugging hole specifically includes: An air guide pad and an aluminum sheet are sequentially placed on the PCB board, wherein the air guide pad is provided with a first through hole, the aluminum sheet is provided with a second through hole, and the first through hole, the second through hole and the second blind hole are arranged opposite to each other; The second blind hole is filled with Sumitomo ACE-9P plugging ink.

[0011] In some optional embodiments, after the cover is plated with holes, the method further comprises: For the outer layer circuit, DuPont dry film LDI8338 is used to stick a dry film on the surface of the PCB board, and the exposure is performed by LDI method, and the PCB board is etched by vacuum DES, wherein the line width / line spacing tolerance of the outer layer circuit is ±20%.

[0012] In some optional embodiments, before pressing, the method further includes: Inner circuit: Hitachi dry film FL-1825A is used to laminate the core board, which is then exposed using LDI and then etched using DES to produce the inner circuit.

[0013] According to another aspect of an embodiment of the present invention, a device for manufacturing a high-voltage and high-current automotive PCB board is provided, and the device is used to execute the above-mentioned high-voltage and high-current automotive PCB board manufacturing method to manufacture a printed circuit board.

[0014] The method and device for manufacturing a high-voltage and high-current automotive PCB board of the present invention have the beneficial effects that: the present invention comprises the following steps: pressing, obtaining a core board, and pressing a plurality of the core boards to form a PCB board; mechanical drilling, drilling a first blind hole in the PCB board by a controlled depth drilling method; laser drilling, processing the first blind hole to form a second blind hole by laser ablation at the bottom of the first blind hole; plasma cleaning, cleaning the second blind hole by plasma; PTH+electroplating, electroplating the PCB board by a high aspect ratio electroplating solution, forming a first electroplating layer on the surface of the blind hole; resin plugging, resin plugging the second blind hole after electroplating by a local plugging method of an empty aluminum sheet; cover electroplating hole: performing a second electroplating at the hole mouth of the second blind hole after plugging to complete the blind hole manufacturing.

[0015] When making extra-large blind holes on automotive PCBs, mechanical deep drilling is used to drill to a certain depth, and then laser drilling is used to ablate the inner target layer to achieve the processing and production of extra-large blind holes. This avoids the problems of laser drilling being unable to process extra-large blind holes and mechanical drilling penetrating more dielectric layers resulting in insufficient thickness, and meets the requirements of extra-large blind holes to withstand high voltage and high current.

[0016] The above description is only an overview of the technical solution of the embodiment of the present invention. In order to more clearly understand the technical means of the embodiment of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the embodiment of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are only used to illustrate the embodiments and are not to be considered as limiting the present invention. In addition, the same reference symbols are used to represent the same components throughout the accompanying drawings. In the accompanying drawings: Figure 1 A schematic flow chart of a method for manufacturing a high-voltage and high-current automotive PCB board according to Embodiment 1 of the present invention is shown; Figure 2 A schematic diagram of a PCB board is shown for a method for manufacturing a high-voltage and high-current automotive PCB board according to Embodiment 2 of the present invention; Figure 3 A schematic diagram of the mechanical drilling process provided by the present invention is shown; Figure 4 A schematic diagram of laser drilling processing provided by the present invention is shown; Figure 5 A schematic diagram of the processing of resin hole filling provided by the present invention is shown; Figure 6 A schematic diagram of processing the cover electroplating hole provided by the present invention is shown; Reference numerals: 1. PCB board; 2. first blind hole; 3. ablation area; 4. resin; 5. air guide pad; 6. aluminum sheet; 7. blind hole. DETAILED DESCRIPTION

[0018] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0019] Embodiment 1: Figure 1 An embodiment of a method for manufacturing a high-voltage and high-current automotive PCB is shown. The method is used to manufacture large blind vias on an automotive PCB. The method comprises: 110, pressing, obtaining the core board, and pressing multiple core boards to form a PCB board; in step 110, during pressing, specifically including: aligning the core boards by means of fusion + rivets, measuring the inter-layer alignment after the core boards are aligned, making the layer deviation tolerance of the core boards + / -0.1mm; measuring the expansion and contraction coefficients of all core boards by means of target cutting and grinding lines, and adjusting the drill belt according to the average of the expansion and contraction coefficients.

[0020] 120, mechanical drilling, drilling a first blind hole in the PCB board by controlling the depth of drilling; in step 120, refer to Figure 3 In mechanical drilling, a flat-bottom drill bit is used to drill a first blind hole 2 from the first board of the PCB board 1 according to a first preset depth, wherein the depth tolerance of the controlled depth drilling is + / -0.1 mm.

[0021] 130, laser drilling, the first blind hole is processed to form a second blind hole by laser ablation at the bottom of the first blind hole; in step 130, see Figure 4 The bottom of the first blind hole is the ablation area 3. In laser drilling, laser ablation is performed at the bottom of the first blind hole at a second preset depth by a circumferential ablation method. When making an extra-large blind hole, multiple laser beams are used for ablation when one laser beam cannot complete the blind hole. This solution moves the X and Y axis moments of the laser beam so that the laser beam ablates around the laser area. The pulse width of the laser beam is 15μm and the energy is 30.5mj. The number of pulses can be determined according to the size of the laser area. For example, when the laser area is 0.425mm, the number of pulses can be 6.

[0022] 140, plasma cleaning, cleaning the second blind hole by plasma; in step 140, during the plasma cleaning, it also includes: confirming by the first slice detection whether the bottom of the second blind hole has a positive etch greater than 2um, if so, proceed to the next step, otherwise re-perform laser drilling.

[0023] 150, PTH+ electroplating, electroplating the PCB board with a high aspect ratio electroplating solution to form a first electroplating layer on the surface of the blind hole; in step 150, the PTH+ electroplating also includes: confirming through a second slice detection whether the hole copper of the second blind hole is greater than or equal to 18um, if so, proceed to the next step, otherwise, perform a second PTH+ electroplating, wherein the second PTH+ electroplating requires brushing and micro-etching.

[0024] 160, resin plugging, the second blind hole after electroplating is plugged with resin by means of partial plugging of an empty aluminum sheet; in step 160, see Figure 5 The resin plugging method specifically includes: filling the air guide pad 5 and the aluminum sheet 6 on the PCB board in sequence, wherein the air guide pad is provided with a first through hole, the aluminum sheet is provided with a second through hole, and the first through hole, the second through hole and the second blind hole are arranged oppositely; the second blind hole is filled with the plugging ink 4 of Sumitomo ACE-9P.

[0025] 170, cover electroplating hole: after plugging the hole, the second blind hole is electroplated for the second time to complete the blind hole production. Figure 6 , then PTH+ electroplating is performed on the hole mouth resin, and the copper thickness is controlled at 12.5+ / -2.5μm, and finally a blind hole 7 is formed.

[0026] The present invention processes super-large blind holes through the above steps. The aperture of the blind hole is ≥0.6mm and the depth is ≥0.6mm. After mechanical deep drilling is used to a certain depth, laser drilling is performed to ablate the inner target layer to realize the processing and production of super-large blind holes. The problems of laser drilling being unable to process super-large blind holes and mechanical drilling penetrating more dielectric layers resulting in insufficient thickness are avoided, and the requirements of super-large blind holes for withstanding high voltage and high current are met.

[0027] Embodiment 2: This embodiment is based on embodiment 1, and this embodiment further improves embodiment 1. Figure 2In a specific example, the material selection of the PCB board of this application: select high Tg materials with good pressure resistance, and the material TG value DSC 190℃. The stacking design of the PCB board: the finished board thickness is 2.87 + / -10% mm. The PCB is L2 / 3, L6 / 7 CORE designed to be 0.406MM 2 / 2 without copper, and L1-2 and L7-8 are designed to be 1080RC65%*3. The requirements for the super-large blind holes of the PCB board: the L1-3 blind hole has a diameter of 0.6mm, which can drill through the L3 layer without drilling through the L4 layer, and the depth-to-diameter ratio is about 1.2:1. The specific processing steps of the PCB board are as follows: Inner circuit: The dry film type used for lamination is Hitachi dry film FL-1825A. The exposure adopts LDI method to make the graphics of inner core board L2 / 3, L4 / 5, L6 / 7. The DES etching line width / line spacing tolerance is ±20%. The line width and line spacing control CPK≥1.67. The line width is measured at the lower width. The minimum hole ring of the inner layer is ≥25μm.

[0028] Lamination: Multiple core boards are aligned by fusion + rivets. After fusion, the inter-layer alignment is measured, and the layer deviation tolerance is + / -0.1mm. Lamination adopts high Tg FR4 program, and the target cutting line measures the expansion and contraction of all boards, and the drill belt is adjusted according to the average expansion and contraction. The laser measurement of board thickness is fully measured, and the board thickness is controlled at 2.76mm + / -0.27mm.

[0029] Mechanical controlled deep drilling: The thickness of L1-3 layers is about 0.725mm. The mechanical deep drilling is used to make the first board. A flat-bottom drill bit is used. The depth is controlled at 0.71+ / -0.1mm. The first board is sliced ​​to confirm the dielectric thickness of the hole drilled through the copper surface of the L3 layer. The depth setting is set to the thickness of the layer to be drilled through -0.15mm, not leaving too much thickness for laser drilling, ensuring that the laser drilling can efficiently complete the remaining thickness. The depth tolerance of the deep drilling is + / -0.1mm, ensuring that the mechanical deep drilling does not damage the copper of the layer to be drilled through.

[0030] Laser drilling: Based on the original deep drilling of the large hole, there is still about 0.10mm dielectric thickness that has not been drilled through. This part of the dielectric thickness is processed by laser ablation to achieve copper connection with the 2OZ base copper of the L3 layer. The copper thickness of the layer that cannot be drilled through must be ≥ 2OZ and cannot be burned through by the laser.

[0031] Plasma cleaning: Use plasma to remove mechanical deep drilling and laser drilling contamination, and slice to confirm the positive etch effect of mechanical holes above 2um.

[0032] PTH+ electroplating: It is made by electroplating blind holes with high aspect ratio. The second electroplating needs to be brushed and micro-etched. The electroplating needs to be reversed. The large blind holes need to be sliced ​​to see the copper thickness. The copper thickness of the holes is controlled at a minimum of 18um and an average of 20um.

[0033] Resin plugging: vacuum aluminum sheet local plugging method is adopted, and Sumitomo ACE-9P (high TG) ink is used. The plugging effect of 0.9mm mechanical blind hole is confirmed on the first piece, and the fullness of the resin plugging is scanned after plugging.

[0034] Cover hole plating: PTH+ plating is performed on the hole mouth resin, and the copper thickness is 12.5+ / -2.5μm.

[0035] Outer circuit: The film is made of dry film type: DuPont dry film LDI8338, and the exposure adopts LDI method to make the outer circuit pattern, and the 4 circuit alignment holes drilled by drilling are aligned, and the circuit alignment tolerance is + / -0.1mm. The outer layer is vacuum DES etched, the line width / line spacing tolerance is ±20%, the line width is measured on the lower side, the line width / line spacing tolerance is ±20%, the pad is measured on the upper side, and the distance from optical point to optical point is measured. The line width and line spacing control CPK≥1.67.

[0036] Embodiment 3: According to another aspect of an embodiment of the present invention, a device for manufacturing a high-voltage and high-current automotive PCB board is provided, and the device is used to execute the above-mentioned high-voltage and high-current automotive PCB board manufacturing method to manufacture a printed circuit board.

[0037] The present invention comprises the following steps: pressing, obtaining a core board, and pressing a plurality of core boards to form a PCB board; mechanical drilling, drilling a first blind hole in the PCB board by a controlled depth drilling method; laser drilling, processing the first blind hole to form a second blind hole by a laser ablation method at the bottom of the first blind hole; plasma cleaning, cleaning the second blind hole by plasma; PTH+electroplating, electroplating the PCB board by a high aspect ratio electroplating solution, forming a first electroplating layer on the surface of the blind hole; resin plugging, resin plugging the second blind hole after electroplating by a local plugging method of an empty aluminum sheet; and cover electroplating hole: performing a second electroplating at the hole mouth of the second blind hole after plugging to complete the blind hole production.

[0038] When making extra-large blind holes on automotive PCBs, mechanical deep drilling is used to drill to a certain depth, and then laser drilling is used to ablate the inner target layer to achieve the processing and production of extra-large blind holes. This avoids the problems of laser drilling being unable to process extra-large blind holes and mechanical drilling penetrating more dielectric layers resulting in insufficient thickness, and meets the requirements of extra-large blind holes to withstand high voltage and high current.

[0039] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. Similarly, in order to simplify the present invention and help understand one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, the various features of the embodiments of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. Wherein, the claims that follow the specific embodiment are hereby expressly incorporated into the specific embodiment, wherein each claim itself is a separate embodiment of the present invention.

[0040] Those skilled in the art will appreciate that the modules in the devices in the embodiments may be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component, and further may be divided into a plurality of submodules or subunits or subcomponents. Except that at least some of such features and / or processes or units are mutually exclusive.

[0041] It should be noted that the above embodiments illustrate the present invention rather than limit it, and that those skilled in the art may design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets shall not be construed as a limitation on the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the presence of multiple such elements. The present invention may be implemented with the aid of hardware comprising several different elements and with the aid of appropriately programmed computers. In a unit claim that lists several systems, several of these systems may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order. These words may be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be understood as limitations on the order of execution.

Claims

1. A method for manufacturing a high voltage and high current automotive PCB board, characterized in that: The method includes: Pressing, obtaining a core board, and pressing a plurality of the core boards together to form a PCB board; Mechanical drilling, drilling a first blind hole on the PCB board by controlled depth drilling; Laser drilling, forming a second blind hole by laser ablation at the bottom of the first blind hole; Plasma cleaning, cleaning the second blind hole by plasma; PTH+ electroplating, electroplating the PCB board with a high aspect ratio electroplating solution to form a first electroplating layer on the surface of the blind hole; Resin plugging: the second blind hole after electroplating is plugged with resin by means of partial plugging of empty aluminum sheet; Cover plated hole: After the plug hole is plugged, the second blind hole is electroplated for the second time to complete the blind hole production.

2. The method for manufacturing a high-voltage and high-current automotive PCB board according to claim 1, characterized in that: In the mechanical drilling, A flat bottom drill bit is used to drill a first blind hole from the first board of the PCB board according to a first preset depth, wherein the depth tolerance of the controlled depth drilling is + / -0.1 mm.

3. The method for manufacturing a high voltage and high current automotive PCB board according to claim 2, characterized in that: In the laser drilling, Laser ablation is performed at a second preset depth at the bottom of the first blind hole by a circumferential ablation method.

4. The method for manufacturing a high voltage and high current automotive PCB board according to claim 1, characterized in that: In the pressing, specifically including: The core plates are aligned by fusion + rivet method, and the inter-layer alignment is measured after the core plates are aligned, so that the layer deviation tolerance of the core plates is + / -0.1mm; the expansion and contraction coefficients of all core plates are measured by target cutting and grinding lines, and the drill belt is adjusted according to the average value of the expansion and contraction coefficients.

5. The method for manufacturing a high voltage and high current automotive PCB board according to claim 1, characterized in that: In the plasma cleaning, it also includes: The first slice detection is used to confirm whether the bottom of the second blind hole has a positive etch back greater than 2 um. If yes, proceed to the next step; otherwise, laser drilling is performed again.

6. The method for manufacturing a high voltage and high current automotive PCB board according to claim 1, characterized in that: The PTH+ plating also includes: The second section test is used to confirm whether the copper of the second blind hole is greater than or equal to 18um. If so, proceed to the next step, otherwise, perform a second PTH+ electroplating, wherein brushing and micro-etching are required in the second PTH+ electroplating.

7. The method for manufacturing a high voltage and high current automotive PCB board according to claim 1, characterized in that: The resin plugging hole specifically comprises: An air guide pad and an aluminum sheet are sequentially placed on the PCB board, wherein the air guide pad is provided with a first through hole, the aluminum sheet is provided with a second through hole, and the first through hole, the second through hole and the second blind hole are arranged opposite to each other; The second blind hole is filled with Sumitomo ACE-9P plugging ink.

8. The method for manufacturing a high voltage and high current automotive PCB board according to claim 1, characterized in that: After the cover is plated with holes, further comprising: For the outer layer circuit, DuPont dry film LDI8338 is used to stick a dry film on the surface of the PCB board, and the exposure is performed by LDI method, and the PCB board is etched by vacuum DES, wherein the line width / line spacing tolerance of the outer layer circuit is ±20%.

9. The method for manufacturing a high voltage and high current automotive PCB board according to claim 1, characterized in that: Before pressing, it also includes: Inner circuit: Hitachi dry film FL-1825A is used to laminate the core board, which is then exposed using LDI and then etched using DES to produce the inner circuit.

10. A device for manufacturing a high voltage and high current automotive PCB board, characterized in that: The device is used to execute the method for manufacturing a high-voltage and high-current automotive PCB board as described in any one of claims 1 to 9 to manufacture a printed circuit board.

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