Processing method of through hole of circuit board formed by stacking PTFE (Polytetrafluoroethylene) and circuit board

Abstract

The invention relates to the field of printed circuit board manufacturing, and discloses a PTFE stacked circuit board through hole processing method and a circuit board, and the PTFE stacked circuit board through hole processing method comprises the steps that a substrate is provided, the substrate comprises a circuit layer and a PTFE layer which are stacked, and the substrate is provided with a first side and a second side which are opposite to each other; a through hole is machined in the substrate from the first side in a mechanical drilling mode, and the through hole penetrates through the circuit layer and the PTFE layer; the through hole is subjected to glue cleaning treatment in a CO2 laser mode from the second side, an aperture adopted by CO2 laser and the through hole are coaxially arranged, and the diameter of the aperture is larger than that of the through hole. According to the processing method of the through holes of the circuit board of the stacked PTFE structure and the circuit board provided by the invention, the problem of poor functional open circuit caused by incapability of effectively connecting circuit layers of the circuit board after subsequent copper plating due to incapability of completely removing slag in all the through holes in related technologies can be improved.

Description

Technical Field

[0001] The present application relates to the field of printed circuit board manufacturing, and in particular to a method for processing through holes in a PTFE laminated circuit board and a circuit board. Background Art

[0002] Some special-purpose circuit boards on the market, such as multilayer boards, require the use of PTFE (Polytetrafluoroethylene) laminates, and through holes need to be processed on the PTFE laminated circuit boards. Generally speaking, the conventional method for processing through holes on PTFE laminated circuit boards is to first mechanically drill holes, and then use processes such as degumming or plasma, high-pressure water washing, and grinding to further improve the problem of glue residue blocking the holes.

[0003] Since the material used in the PTFE stack is a composite PTFE structure, which is relatively soft and sticky, when the conventional processing method is used to make the circuit board, it is easy to pull the connecting layer of the hole wall of the through hole to the center of the hole, forming glue residue, causing glue residue type hole blocking, and even if plasma (or glue removal), high-pressure water washing and grinding processes are used for subsequent treatment, it cannot be guaranteed that all the glue residue in the through hole is removed. As a result, in the subsequent copper plating process, due to the obstruction of the glue residue in the through hole, the black shadow and copper plating solution cannot be normally and evenly immersed in the hole wall. After copper plating, the circuit layers of the circuit board cannot be effectively connected, resulting in functional open circuit defects. Summary of the invention

[0004] The present application provides a method for processing through-holes in a PTFE-stacked circuit board and a circuit board, which can improve the problem in the related art that it is impossible to ensure that all slag in the through-holes are completely removed, resulting in the inability to effectively connect the circuit layers of the circuit board after subsequent copper plating, causing functional open circuit defects.

[0005] In a first aspect, an embodiment of the present application provides a method for processing a through hole of a PTFE stacked circuit board, comprising:

[0006] Providing a substrate, the substrate comprising a circuit layer and a PTFE layer stacked in layers, the substrate having a first side and a second side opposite to each other;

[0007] Processing a through hole on the substrate by mechanical drilling from the first side, wherein the through hole penetrates the circuit layer and the PTFE layer;

[0008] The through hole is subjected to a clearing treatment by using a CO2 laser on the second side. The aperture used by the CO2 laser is coaxially arranged with the through hole, and the diameter of the aperture is larger than the diameter of the through hole.

[0009] In some embodiments, when the through hole is machined on the substrate by mechanical drilling by the first side, a positioning hole is machined on the substrate; and the through hole is cleared by the second side using the CO2 laser with the positioning hole as a positioning reference.

[0010] In some embodiments, there are multiple positioning holes, and the multiple positioning holes are distributed at intervals.

[0011] In some embodiments, the difference between the diameter of the aperture and the diameter of the through hole is 0.075 mm-0.150 mm.

[0012] In some of the embodiments, the CO2 laser uses a pulse wave with a pulse width of 10μs-15μs, a main reference energy of 20mj-30mj, and a pulse number of 1Shot-3Shot.

[0013] In some of the embodiments, the number of the circuit layers and the number of the PTFE layers are both plural, and at least one circuit layer is disposed between two adjacent PTFE layers.

[0014] In some embodiments, the circuit layer includes a circuit and a reinforcement portion, the circuit and the reinforcement portion are spaced apart, there are multiple through holes, some of the through holes penetrate the circuit and the PTFE layer, and some of the through holes penetrate the reinforcement portion and the PTFE layer.

[0015] In some of the embodiments, the substrate further includes a connecting layer, part of the connecting layer is located between two adjacent PTFE layers, and part of the connecting layer is located between the circuit layer and the PTFE layer.

[0016] In some embodiments, after the through hole is cleared by the second side using a CO2 laser, the substrate is polished and / or plasma treated.

[0017] In a second aspect, an embodiment of the present application provides a circuit board, which is manufactured by the processing method of the through-hole of the PTFE stacked circuit board as described in the first aspect.

[0018] The PTFE-stacked circuit board through-hole processing method provided in the embodiment of the present application is manufactured, and the beneficial effect is: since the through-hole is first processed on the substrate by mechanical drilling on the first side, the through-hole passes through the circuit layer and the PTFE layer, and the through-hole is then cleared of glue by CO2 laser on the second side, the aperture used by the CO2 laser is coaxially arranged with the through-hole, and the diameter of the aperture is larger than the diameter of the through-hole, so not only can all the glue residue inside the through-hole be completely vaporized, thereby removing all the glue residue in the through-hole and preventing abnormal glue residue-type hole blocking, but also the circuit layers of the circuit board can be effectively connected after subsequent copper plating to ensure the functionality of the circuit board, and the problem of poor copper breakage in the hole after subsequent copper plating caused by excessive concave amount of the through-hole wall can be avoided.

[0019] The beneficial effects of the circuit board provided in the present application compared with the prior art can be referred to the description of the beneficial effects of the processing method of the PTFE stacked circuit board through hole provided in the present application compared with the prior art, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0021] Figure 1 It is a structural schematic diagram of a circuit board in the prior art;

[0022] Figure 2 Using existing processing methods Figure 1 The schematic diagram of the circuit board after cleaning and degumming is shown;

[0023] Figure 3 This is a flow chart of a method for processing a through hole of a circuit board with a PTFE stack structure in one embodiment of the present application;

[0024] Figure 4 This is a schematic diagram of the structure of a substrate in one of the embodiments of the present application;

[0025] Figure 5 The first side is mechanically drilled Figure 4 A schematic diagram of a through hole being machined on a substrate shown;

[0026] Figure 6 The second side uses CO2 laser to Figure 5 The schematic diagram of the through hole shown in the figure when the glue is removed;

[0027] Figure 7The second side uses CO2 laser to Figure 5 Schematic diagram of the through hole after the resin removal process is shown.

[0028] The meanings of the marks in the figure are:

[0029] 1. Circuit board; 2. Through hole; 3. Glue residue;

[0030] 100. Substrate;

[0031] 101, first side; 102, second side; 10, circuit layer; 11, circuit; 12, reinforcement; 20, PTFE layer; 30, connection layer; 40, through hole; 50, glue residue;

[0032] 200, drill bit;

[0033] 300. Laser head. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0035] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0037] References to "one embodiment", "some embodiments" or "an embodiment" described in the specification of this application mean that a particular feature, structure or characteristic described in conjunction with the embodiment is included in one or more embodiments of the present application. Thus, the phrases "in one embodiment", "in some other embodiments", "in some other embodiments", etc., which appear at different places in this specification, do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. In addition, in one or more embodiments, particular features, structures or characteristics may be combined in any suitable manner.

[0038] In order to illustrate the technical solution of the present application, a description is given below with reference to specific drawings and embodiments.

[0039] Some special-purpose circuit boards on the market, such as multilayer boards, require PTFE laminates, and through holes need to be processed on the PTFE laminated circuit boards. Generally, the conventional method for processing through holes on PTFE laminated circuit boards is to first mechanically drill holes, and then use processes such as degumming or plasma, high-pressure water washing, and grinding to further improve the problem of glue residue blocking the holes.

[0040] Please refer to Figure 1 and Figure 2 , Figure 1 is a schematic diagram of the structure of a circuit board 1 in the prior art, Figure 2 Using existing processing methods Figure 1 The schematic diagram shown is a circuit board 1 after cleaning and degumming treatment.

[0041] Since the material used in the PTFE stack is a composite PTFE structure, which has relatively soft and sticky properties, when the circuit board 1 is made by conventional processing methods, it is easy to pull the PTFE and other dielectric layers on the hole wall of the through hole 2 to the center of the hole, forming glue residue 3, causing glue residue type hole blocking, and even if plasma (or glue removal), high-pressure water washing and grinding processes are used for subsequent treatment, it cannot be guaranteed that all the glue residue 3 in the through hole 2 is completely removed, which leads to the fact that in the subsequent copper plating process, due to the obstruction of the glue residue 3 in the through hole 2, the black shadow and the copper plating solution cannot be normally and evenly immersed in the hole wall, and the circuit layers of the circuit board 1 cannot be effectively connected after copper plating, resulting in functional open circuit defects.

[0042] In view of this, the present application provides a method for processing through holes in a PTFE-stacked circuit board and a circuit board, in which a through hole is first processed on a substrate by mechanical drilling on the first side, the through hole passes through the circuit layer and the PTFE layer, and then the through hole is cleared of glue by a CO2 laser on the second side. The aperture used by the CO2 laser is coaxially arranged with the through hole, and the diameter of the aperture is larger than the diameter of the through hole. Therefore, not only can all the glue residue inside the through hole be completely vaporized, thereby removing all the glue residue in the through hole and preventing abnormal hole blocking by glue residue, but also the circuit layers of the circuit board can be effectively connected after subsequent copper plating to ensure the functionality of the circuit board, and the problem of poor copper breakage in the hole after subsequent copper plating caused by excessive concaveness of the through hole wall can be avoided.

[0043] Please refer to Figures 3 to 7 , Figure 3 This is a flow chart of a method for processing a PTFE laminated circuit board through hole 40 in one embodiment of the present application. Figure 4 is a schematic diagram of the structure of a substrate 100 in one embodiment of the present application. Figure 5The first side 101 is mechanically drilled Figure 4 The schematic diagram of processing the through hole 40 on the substrate 100 shown in FIG. Figure 6 The second side 102 uses a CO2 laser to Figure 5 The schematic diagram of the through hole 40 shown in FIG. Figure 7 The second side 102 uses a CO2 laser to Figure 5 The through hole 40 is shown as a schematic diagram after the resin removal process.

[0044] In a first aspect, an embodiment of the present application provides a method for processing a PTFE laminated circuit board through hole 40, comprising:

[0045] S100 : providing a substrate 100 , the substrate 100 comprising a circuit layer 10 and a PTFE layer 20 which are stacked, and the substrate 100 has a first side 101 and a second side 102 which are opposite to each other.

[0046] Specifically, the substrate 100 may go through processes such as cutting, primary drilling, layer pattern circuit 11, inner layer AOI (Automated Optical Inspection), browning and lamination, punching, debonding, copper reduction, and X-Ray drilling target.

[0047] Cutting: Cut into sheets and transfer to the drilling process.

[0048] One-time drilling: drilling positioning holes for stacking boards and positioning holes for inner layer pattern exposure.

[0049] Inner layer graphic circuits: exposure, development, and etching of inner layer circuits.

[0050] Inner layer AOI: Scan to confirm the quality of inner layer products.

[0051] Browning: Roughen the copper surface of the inner layer product to improve the bonding strength.

[0052] Lamination and pressing: Use the previously drilled lamination positioning holes to position, and press together with the outer material and thermosetting adhesive.

[0053] Punching: Punch out the waste border to prevent waste from contaminating the horizontal line and facilitate subsequent operations.

[0054] Glue removal: Remove excess residual glue from the board surface and edges to avoid quality abnormalities caused by residual glue during subsequent copper plating and graphics.

[0055] Copper reduction: Reduce the copper thickness of the outer layer material to prepare for subsequent graphic circuits.

[0056] X-Ray Drill Target: Identify the inner PAD (pad) to drill the positioning hole for mechanical drilling, and classify the product by expansion and contraction.

[0057] The number of circuit layers 10 and the number of PTFE layers 20 can be multiple. The PTFE layer 20 is located between two adjacent circuit layers 10. The circuit layer 10 can be a copper layer. A connecting layer 30 such as AD (Adhesive) glue can also be provided to connect two adjacent PTFE layers 20 and adjacent circuit layers 10 and PTFE layers 20. The PTFE layer 20 and the connecting layer 30 can form a dielectric layer.

[0058] S200 : machining a through hole 40 on the substrate 100 through the first side 101 by mechanical drilling, wherein the through hole 40 penetrates the circuit layer 10 and the PTFE layer 20 .

[0059] Specifically, the drill bit 200 of the drilling machine can be used to process the through hole 40 on the substrate 100. There can be one or more through holes 40, which can be drilled from the first layer to the Nth layer of the substrate 100. When the number of circuit layers 10 and the number of PTFE layers 20 are both multiple, the through hole 40 can penetrate all the circuit layers 10 and all the PTFE layers 20. The through hole 40 can also penetrate the connection layer 30.

[0060] For example, the aperture of the through hole 40 can be 0.15mm-0.25mm. A matching drill bit 200 with a target aperture of 0.15mm-0.25mm can be used with a mechanical drill rig, and the corresponding expansion and contraction drill belt can be called to process the through hole 40. The size of the drill bit 200 used for mechanical drilling can be selected according to conventional production design requirements without special processing. The rotation speed is generally set to 160krpm-180krpm, the lowering speed is generally set to 1.8m / min-2.0m / min, the return speed is generally set to 18m / min-20m / min, and the service life is 600Hits-1000Hits.

[0061] The purpose of machine drilling the through hole 40 is to drill out the hole shape of the through hole 40 first. Because this type of circuit board has thick copper and many layers, it is unrealistic to directly use a laser to drill the through hole 40. This is because laser drilling requires repeated laser ablation due to the large number of layers and thick copper, which can easily lead to the through hole 40 being trumpet-shaped, the hole shape being insufficiently vertical, and the hole wall roughness being poor. Not only is the efficiency low, but the hole shape does not meet product requirements.

[0062] It is understandable that after the through hole 40 is machined on the substrate 100 by mechanical drilling from the first side 101, because the PTFE layer 20 material has relatively soft and sticky properties, the PTFE layer 20 and the connecting layer 30 of the hole wall of the through hole 40 are easily pulled to the center of the through hole 40 during the mechanical drilling process, thereby forming glue residue 50 and causing hole blockage.

[0063] S300 : performing a clearing treatment on the through hole 40 by using a CO2 laser from the second side 102 . The aperture used by the CO2 laser is coaxially arranged with the through hole 40 , and the diameter of the aperture is larger than the diameter of the through hole 40 .

[0064] Specifically, the laser head 300 of the CO2 laser device can be used to retrieve the corresponding expansion and contraction drill tape to perform glue removal processing on the through hole 40, and the through hole 40 can be removed from the Nth layer to the 1st layer by CO2 laser.

[0065] Since the aperture used by the CO2 laser is coaxially arranged with the through hole 40 and the diameter of the aperture is larger than the diameter of the through hole 40, when the through hole 40 is cleared by the CO2 laser from the second side 102, the outer circle of the laser cross section covers the through hole 40 that needs to be cleared, so that all the glue residue 50 inside the through hole 40 can be completely vaporized, thereby removing all the glue residue 50 in the through hole 40 to prevent abnormal hole blocking by glue residue. After subsequent copper plating, the circuit layers 10 of the circuit board can be effectively connected to ensure the functionality of the circuit board.

[0066] It is understandable that the first side 101 can be placed upward first, and after the through hole 40 is processed on the substrate 100 by mechanical drilling through the first side 101, the second side 102 can be placed upward, and then the through hole 40 can be cleared by CO2 laser through the second side 102.

[0067] It can also be understood that CO2 laser is different from UV (Ultraviolet Rays) laser. CO2 laser cannot act on the circuit layer 10 (copper layer) that has not been browned or blackened. It will not damage the hole wall and hole surface due to energy greater than the hole diameter. It can ensure the hole diameter and hole shape while clearing the glue residue 50 in the through hole 40, avoiding the problem of incomplete glue cleaning caused by the difference in precision between the two drillings.

[0068] It should be noted that, since the through hole 40 is first machined on the substrate 100 by mechanical drilling from the first side 101, the time for the drill bit 200 to act on the PTFE layer 20 and the connecting layer 30 corresponding to the first side 101 (upper layer) will be relatively longer, and therefore the shrinkage amount of the PTFE layer 20 and the connecting layer 30 corresponding to the upper layer of the through hole 40 will also be relatively larger. If the through hole 40 is then cleared by CO2 laser from the first side 101, that is, the direction in which the through hole 40 is machined on the substrate 100 by mechanical drilling and the direction in which the through hole 40 is cleared by CO2 laser are the same, the shrinkage amount of the through hole 40 at the PTFE layer 20 and the connecting layer 30 corresponding to the upper layer will be further increased, thereby easily causing the through hole 40 to have an excessively large concave amount of the hole wall, resulting in poor copper fracture after subsequent copper plating. Therefore, reverse clearing is required when clearing the through hole 40.

[0069] From the above, it can be seen that the processing method of the PTFE stacked circuit board through hole 40 provided in the embodiment of the present application is manufactured. Since the through hole 40 is first processed on the substrate 100 by mechanical drilling from the first side 101, the through hole 40 passes through the circuit layer 10 and the PTFE layer 20, and then the through hole 40 is cleared by the second side 102 using a CO2 laser. The aperture used by the CO2 laser is coaxially arranged with the through hole 40, and the diameter of the aperture is larger than the diameter of the through hole 40. Therefore, not only can all the glue residue 50 inside the through hole 40 be completely vaporized, thereby removing all the glue residue 50 in the through hole 40 and preventing abnormal glue residue-type hole blocking, but also the circuit layers 10 of the circuit board can be effectively connected after subsequent copper plating to ensure the functionality of the circuit board, and the problem of poor copper breakage in the hole after subsequent copper plating caused by excessive concave amount of the hole wall of the through hole 40 can be avoided.

[0070] In order to improve the alignment between the aperture used by the CO2 laser and the through hole 40 when the through hole 40 is cleared by the CO2 laser from the second side 102, in the present embodiment, when the through hole 40 is machined on the substrate 100 by mechanical drilling from the first side 101, a positioning hole is machined on the substrate 100; and the through hole 40 is cleared by the CO2 laser from the second side 102 using the positioning hole as a positioning reference.

[0071] By adopting the above solution, the aperture used by the CO2 laser can be well matched to the position of the through hole 40, which can ensure effective glue cleaning for each through hole 40 and avoid the problem of poor interlayer conduction caused by abnormal glue residue blocking.

[0072] Optionally, there are multiple positioning holes, and the multiple positioning holes are distributed at intervals.

[0073] With such configuration, the through hole 40 can be cleared by using the positioning hole as a positioning reference from the second side 102 by using a CO2 laser.

[0074] For example, four positioning holes with a hole diameter of 0.5 mm may be provided, and the four positioning holes may be designed on the four corner process edges of the layout of the circuit board.

[0075] It should be noted that when the through hole 40 is processed on the substrate 100 by mechanical drilling on the first side 101, a tool hole is processed on the substrate 100. The tool hole is mainly used for positioning in the later process. This type of hole does not have high requirements on the quality of the hole wall and can use internal multilayer board parameters.

[0076] Optionally, the difference between the diameter of the aperture and the diameter of the through hole 40 is 0.075 mm-0.150 mm, such as 0.075 mm, 0.100 mm, 0.125 mm or 0.150 mm.

[0077] With such an arrangement, all the glue residue 50 inside the through hole 40 can be completely vaporized, thereby removing all the glue residue 50 inside the through hole 40 and preventing abnormal glue residue-type hole blocking. After subsequent copper plating, the circuit layers 10 of the circuit board can be effectively connected to ensure the functionality of the circuit board.

[0078] For example, the aperture of the through hole 40 is 0.15 mm, and an aperture (Mask) matching the aperture of 0.225 mm-0.3 mm is selected during CO2 laser irradiation.

[0079] Please refer to Figure 6 In this embodiment, the CO2 laser uses a pulse wave with a pulse width of 10μs-15μs, a main reference energy of 20mj-30mj, and a pulse number of 1Shot-3Shot.

[0080] By adopting the above solution, it can be ensured that the glue residue 50 in the through hole 40 is cleaned away without damaging the hole wall and hole surface of the through hole 40.

[0081] The number of the circuit layers 10 and the number of the PTFE layers 20 are both plural, and at least one circuit layer 10 is disposed between two adjacent PTFE layers 20 .

[0082] With such arrangement, a multi-layer circuit board can be manufactured by the processing method of the PTFE laminated circuit board through hole 40 provided in the embodiment of the present application.

[0083] For example, the circuit board manufactured by the processing method of the PTFE laminated circuit board through hole 40 provided in the embodiment of the present application can be a high-frequency and high-speed FPC (Flexible Printed Circuit) thick copper multilayer board.

[0084] Optionally, the circuit layer 10 includes a circuit 11 and a reinforcement portion 12 , the circuit 11 and the reinforcement portion 12 are spaced apart, there are multiple through holes 40 , some of the through holes 40 pass through the circuit 11 and the PTFE layer 20 , and some of the through holes 40 pass through the reinforcement portion 12 and the PTFE layer 20 .

[0085] With such a configuration, the reinforcing portion 12 can be used to provide stable support for the PTFE layer 20 , and when a through hole 40 is machined on the substrate 100 by mechanical drilling from the first side 101 , the hole clogging problem caused by the pulling of the PTFE layer 20 by the drill bit 200 can be avoided.

[0086] By way of example, the reinforcing portion 12 may be a dummy copper PAD (pad).

[0087] Optionally, the substrate 100 further includes a connection layer 30 , a portion of the connection layer 30 is located between two adjacent PTFE layers 20 , and a portion of the connection layer 30 is located between the circuit layer 10 and the PTFE layer 20 .

[0088] With such arrangement, the processing method of the PTFE laminated circuit board through hole 40 provided in the embodiment of the present application can be used to manufacture a multi-layer circuit board, and the two PTFE layers 20 and the adjacent circuit layer 10 and PTFE layer 20 are tightly connected.

[0089] By way of example, the connection layer 30 may be AD glue or the like.

[0090] Optionally, after the through hole 40 is subjected to a resist removal treatment by CO 2 laser on the second side 102 , the substrate 100 is subjected to a grinding and / or plasma treatment.

[0091] With such a configuration, the circuit layer 10 burrs that may be generated when the through hole 40 is machined on the substrate 100 from the first side 101 by mechanical drilling can be removed by grinding the substrate 100, and the carbon powder in the through hole 40 can be removed by plasma treatment of the substrate 100, and the hole wall of the through hole 40 can be roughened to facilitate subsequent black shadows and copper plating.

[0092] The substrate 100 provided in the embodiment of the present application may be a multilayer board. In one embodiment, the substrate 100 sequentially includes a circuit layer 10 (thickness of 12 μm), a PTFE layer 20 (thickness of 100 μm), an AD glue (thickness of 25 μm), a circuit layer 10 (thickness of 18 μm), a PTFE layer 20 (thickness of 100 μm), a circuit layer 10 (thickness of 18 μm), an AD glue (thickness of 25 μm), a PTFE layer 20 (thickness of 100 μm), and a circuit layer 10 (thickness of 12 μm). In another embodiment, the substrate 100 sequentially includes a circuit layer 10 (thickness of 12 μm), a PTFE layer 20 (thickness of 100 μm), an AD glue (thickness of 25 μm), a PTFE layer 20 (thickness of 100 μm), an AD glue (thickness of 25 μm), a PTFE layer 20 (thickness of 100 μm), and a circuit layer 10 (thickness of 12 μm).

[0093] Among them, the aperture of the through hole 40 is 0.15mm-0.25mm, the drill bit 200 used for mechanical drilling is set to 160krpm-180krpm, the cutting speed is generally set to 1.8m / min-2.0m / min, the returning speed is generally set to 18m / min-20m / min, and the life is 600hits-1000hits.

[0094] When the second side 102 uses CO2 laser to perform the clearing treatment on the through hole 40, three knife sequences are included: the pulse width of rool1 is 10μs-15μs, the main reference energy is 20mj-30mj, the number of pulses is 1Shot-3Shot, and the corresponding aperture diameter is 0.225mm-0.3mm; the pulse width of rool2 is 10μs-15μs, the number of pulses is 1Shot-3Shot, and the corresponding aperture diameter is 0.225mm-0.3mm; the pulse width of rool3 is 10μs-15μs, the number of pulses is 1Shot-3Shot, and the corresponding aperture diameter is 0.225mm-0.3mm.

[0095] It should be noted that when the material stacking structure of the substrate 100 to be processed and the aperture of the through hole 40 are different, the processing parameters can be adjusted appropriately.

[0096] In a second aspect, an embodiment of the present application provides a circuit board, which is manufactured by the processing method of the circuit board through hole 40 of the PTFE laminated structure as in the first aspect.

[0097] The circuit board provided in the embodiment of the present application is firstly processed on the substrate 100 by mechanical drilling by the first side 101, and the through hole 40 passes through the circuit layer 10 and the PTFE layer 20, and then the through hole 40 is subjected to a glue removal treatment by CO2 laser by the second side 102. The aperture used by the CO2 laser is coaxially arranged with the through hole 40, and the diameter of the aperture is larger than the diameter of the through hole 40. Therefore, not only can all the glue residue 50 inside the through hole 40 be completely vaporized, thereby all the glue residue 50 in the through hole 40 can be cleanly removed to prevent abnormal hole blocking by glue residue, but also the circuit layers 10 of the circuit board can be effectively connected after subsequent copper plating to ensure the functionality of the circuit board, and the problem of poor copper breakage in the hole after subsequent copper plating caused by excessive concave amount of the hole wall of the through hole 40 can be avoided.

[0098] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for processing a through hole of a PTFE stacked circuit board, characterized in that: include: Providing a substrate, the substrate comprising a circuit layer and a PTFE layer stacked in layers, the substrate having a first side and a second side opposite to each other; Processing a through hole on the substrate by mechanical drilling from the first side, wherein the through hole penetrates the circuit layer and the PTFE layer; The through hole is subjected to a clearing treatment by using a CO2 laser on the second side. The aperture used by the CO2 laser is coaxially arranged with the through hole, and the diameter of the aperture is larger than the diameter of the through hole.

2. The method for processing through-holes in a PTFE stacked circuit board according to claim 1, characterized in that: When the through hole is processed on the substrate by mechanical drilling by the first side, a positioning hole is processed on the substrate; and the through hole is cleared by the second side using the CO2 laser with the positioning hole as the positioning reference.

3. The method for processing a through hole of a circuit board with a PTFE stack according to claim 2, characterized in that: There are multiple positioning holes, and the multiple positioning holes are distributed at intervals.

4. The method for processing through-holes in a PTFE stacked circuit board according to claim 1, characterized in that: The difference between the diameter of the aperture and the diameter of the through hole is 0.075 mm-0.150 mm.

5. The method for processing through-holes in a PTFE stacked circuit board according to claim 1, characterized in that: The CO2 laser uses a pulse wave with a pulse width of 10μs-15μs, a main reference energy of 20mj-30mj, and a pulse number of 1Shot-3Shot.

6. The method for processing a through hole of a PTFE laminated circuit board according to any one of claims 1 to 5, characterized in that: The number of the circuit layers and the number of the PTFE layers are both plural, and at least one circuit layer is arranged between two adjacent PTFE layers.

7. The method for processing through-holes in a PTFE stacked circuit board according to claim 6, characterized in that: The circuit layer includes a circuit and a reinforcement part, the circuit and the reinforcement part are arranged at intervals, the number of the through holes is multiple, some of the through holes penetrate the circuit and the PTFE layer, and some of the through holes penetrate the reinforcement part and the PTFE layer.

8. The method for processing through-holes in a PTFE stacked circuit board according to claim 6, characterized in that: The substrate further includes a connection layer, part of the connection layer is located between two adjacent PTFE layers, and part of the connection layer is located between the circuit layer and the PTFE layer.

9. The method for processing a through hole of a PTFE laminated circuit board according to any one of claims 1 to 5, characterized in that: After the through hole is subjected to a resist removal treatment by the second side using a CO2 laser, the substrate is subjected to a grinding and / or plasma treatment.

10. A circuit board, characterized in that: The circuit board is manufactured by the method for processing through holes of a PTFE laminated circuit board as described in any one of claims 1 to 9.

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