Circuit board X-shaped through hole drilling method, equipment, device and system

Abstract

The invention relates to a circuit board X-shaped through hole drilling method, equipment, device and system. The method comprises the steps that a first laser beam is used for drilling a first conductive layer to form a first drill hole; performing drilling processing on the second conductive layer by using the first laser beam to form a second drill hole; and a second laser beam is used for drilling the hole bottom of the first drill hole or the second drill hole to form a third drill hole, and the first drill hole, the second drill hole and the third drill hole are combined to form the X-like through hole. The first laser beam is adopted to correspondingly manufacture the first drill hole and the second drill hole in the two faces of the circuit board, the second laser beam is adopted to manufacture the third drill hole smaller than the first drill hole and the second drill hole in size, the third drill hole enables the first drill hole to be communicated with the second drill hole, and then the X-like through hole is formed in the circuit board. And the industrial pain point caused by manufacturing the X-shaped through hole in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the field of laser processing, and particularly to a drilling method, device, apparatus and system for X-shaped through holes on circuit boards. Background Art

[0002] There is a type of circuit board called a carrier board, which is a transitional circuit board for signal and power connection between chips and circuit boards. Compared with chips, the line width and line spacing of the carrier board are relatively thick; compared with ordinary circuit boards, the line width and line spacing of the carrier board are quite fine. Generally, carrier boards have multiple layers, and the two middle layers are usually made of double-sided boards, which are called core boards. The core board needs to be drilled with X-shaped through holes. The X-shaped through holes have the characteristics of large hole openings at both ends and a narrow waist in the middle. Such X-shaped through holes are more conducive to copper plating in the holes of the core board (it is easy to have a void in the center when plating a straight through hole, that is, an electroplating void).

[0003] Currently, a method of performing two-sided punching on the front and back using a carbon dioxide laser is generally adopted to manufacture X-shaped through holes. For relatively thick core boards, such as those with a thickness of 200 to 300 microns, it is common to use a carbon dioxide laser for two-sided punching to manufacture X-shaped through holes; however, for core boards with a thickness of less than 200 microns, during the process of punching holes on the front and back with a carbon dioxide laser, the depth of each drilled hole (the hole shape is similar to a horn shape) is usually relatively deep. After punching the front and back holes in opposite directions, a straight through hole with a vertical cross-section close to a rectangle is directly formed; if process parameters such as laser energy and action time are reduced to avoid the excessive depth of the carbon dioxide laser beam punching in opposite directions, although an X-shaped hole can be punched, due to the energy and time of laser action being on the lower limit, and the thinning of the conductive layer and / or uneven brownification and / or unevenness of the middle insulating layer, it is very easy to cause the situation that the waist of the manufactured hole is too thick or the waist of the hole is blocked, or even the two drilled holes on both sides are not connected.

[0004] The above are the industry pain points in processing X-shaped through holes on core boards with a thickness less than 200 microns, or even a thickness of only 150 microns, 100 microns, or 50 microns. How to solve these industry pain points is an urgent problem to be solved at present. Summary of the Invention

[0005] The present invention provides a drilling method, device, apparatus and system for X-shaped through holes on circuit boards to solve at least one of the above technical problems.

[0006] In a first aspect, the present invention provides a method for drilling an X-shaped through hole in a circuit board, which uses a first laser beam and a second laser beam to perform drilling processing on the circuit board to fabricate an X-shaped through hole; both the first laser beam and the second laser beam are non-carbon dioxide laser beams; the circuit board at least includes an insulating layer and a first conductive layer and a second conductive layer respectively attached to two surfaces of the insulating layer, and the thickness of the circuit board is less than 200 micrometers; the method for drilling an X-shaped through hole in a circuit board includes:

[0007] In the first step, use the first laser beam to perform drilling processing at a preset position on the first conductive layer that penetrates the first conductive layer but does not penetrate the insulating layer to form a first drill hole.

[0008] In the second step, use the first laser beam to perform drilling processing at a position on the second conductive layer opposite to the first drill hole that penetrates the second conductive layer but is not connected or critically connected to the first drill hole to form a second drill hole; wherein, the size of the second drill hole matches the size of the first drill hole.

[0009] Or, use the second laser beam to perform drilling processing on the insulating layer at the bottom of the first drill hole that does not penetrate the insulating layer to form a third drill hole; wherein, the orifice size of the third drill hole is less than half of the orifice size of the first drill hole.

[0010] In the third step, when the second drill hole is formed in the second step, use the second laser beam to perform drilling processing on the insulating layer at the bottom of the first drill hole or the second drill hole to connect the first drill hole and the second drill hole to form a third drill hole; wherein, the orifice size of the third drill hole is less than half of the orifice size of the first drill hole or the second drill hole; thereby, the first drill hole, the second drill hole, and the third drill hole are combined on the circuit board to form an X-shaped through hole.

[0011] When the third drill hole is formed in the second step, use the first laser beam to perform drilling processing at a position on the second conductive layer opposite to the first drill hole that is connected to the third drill hole to form a second drill hole; wherein, the size of the second drill hole matches the size of the first drill hole; thereby, the first drill hole, the second drill hole, and the third drill hole are combined on the circuit board to form an X-shaped through hole.

[0012] In a second aspect, the present invention provides an apparatus for drilling an X-shaped through hole in a circuit board, including:

[0013] A laser, which is used to generate a first laser beam and a second laser beam, and both the first laser beam and the second laser beam are non-carbon dioxide laser beams.

[0014] A galvanometer scanning and flat-field focusing device, which is connected to the laser, is used to scan and focus the first laser beam and the second laser beam to output the processing spots of the first laser beam and the second laser beam; wherein, the light intensity distribution of the processing spot of the first laser beam is stronger in the central region than in the edge region, and the size of the processing spot of the second laser beam is less than one-half of the size of the processing spot of the first laser beam;

[0015] A controller, which is connected to the galvanometer scanning and flat-field focusing device, is used to control the first laser beam and the second laser beam to perform the method for drilling X-shaped through holes on a circuit board as described above.

[0016] In a third aspect, the present invention provides a device for drilling X-shaped through holes on a circuit board, including a processor, a memory, and a computer program stored in the memory. When the computer program is executed by the processor, it implements the method for drilling X-shaped through holes on a circuit board as described above.

[0017] In a fourth aspect, the present invention provides a system for drilling X-shaped through holes on a circuit board, including a machine table, and further including the device for drilling X-shaped through holes on a circuit board as described above and the device for drilling X-shaped through holes on a circuit board as described above. The device for drilling X-shaped through holes on a circuit board is electrically connected to the device for drilling X-shaped through holes on a circuit board;

[0018] The machine table is used to carry a circuit board;

[0019] The device for drilling X-shaped through holes on a circuit board is used to control the device for drilling X-shaped through holes on a circuit board to perform the method for drilling X-shaped through holes on a circuit board as described above to drill the circuit board carried on the machine table.

[0020] The beneficial effects of the present invention are as follows: In a method, device, apparatus, and system for drilling X-shaped through holes on a circuit board according to the present invention, a first laser beam is used to respectively make a first drill hole and a second drill hole on two sides of the circuit board, and a second laser beam is used to make a third drill hole with a size smaller than the first drill hole and the second drill hole. The third drill hole connects the first drill hole and the second drill hole, thereby forming an X-shaped through hole on the circuit board, solving the industry pain points that occur in the production of X-shaped through holes in the prior art; at the same time, due to the setting of the third drill hole, the industry pain point of blockage of the waist of the traditional X-shaped through hole is avoided; in addition, since the laser beam used is no longer a carbon dioxide laser beam, it is not necessary to perform a browning treatment on the surface of the circuit board, saving the production process. Description of the Drawings

[0021] Figure 1 It is a schematic diagram of the processing and hole formation of an X-shaped through hole in an existing thick circuit board;

[0022] Figure 2 Schematic diagram of the processing and hole formation of the existing X-shaped through-holes in thin circuit boards;

[0023] Figure 3 Flow chart of a method for drilling X-shaped through-holes in a circuit board according to the present invention;

[0024] Figure 4 The first schematic diagram of the processing and hole formation of the X-shaped through-holes in a thin circuit board by using the method of the present invention;

[0025] Figure 5 The second schematic diagram of the processing and hole formation of the X-shaped through-holes in a thin circuit board by using the method of the present invention;

[0026] Figure 6 The third schematic diagram of the processing and hole formation of the X-shaped through-holes in a thin circuit board by using the method of the present invention. Detailed implementation manners

[0027] The principles and features of the present invention will be described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0028] In the existing carrier board, X-shaped through-holes are formed by laser butt welding. The waist of the X-shaped through-hole is relatively thin. During the electroplating process, the waist of the X-shaped through-hole is preferentially electroplated and completed, and then it is relatively easy to fill the shallower and wider hole openings; for electroplating and filling traditional vertically-through holes in the hole wall, if the ratio of the hole diameter to the hole depth is too small, it is easy to electroplate the core, while the X-shaped through-hole is relatively easy to fill.

[0029] As Figure 1 shown, it is a schematic diagram of the processing and hole formation of the X-shaped through-holes in an existing thick circuit board. The circuit board at least includes an insulating layer 2 and a first conductive layer 1 and a second conductive layer 3 respectively attached to the two surfaces of the insulating layer 2; in the prior art, generally, carbon dioxide laser (not marked in the figure) is used for punching holes. The first conductive layer 1 and the second conductive layer 3 are generally thin copper with brownization reduction, and the thickness is only a few micrometers. The carbon dioxide laser drills a first hole 4 on the first conductive layer 1 with the hole bottom close to the second conductive layer 3, and the carbon dioxide laser drills a second hole 5 on the second conductive layer 3 with the hole bottom close to the first conductive layer 1. The axis deviation between the first hole 4 and the second hole 5 should not be too large, and it needs to be less than 30 micrometers, otherwise the first hole 4 and the second hole 5 will be misaligned and cannot penetrate; the depths of the first hole 4 and the second hole 5 in the direction perpendicular to the surface of the circuit board need to overlap, otherwise the first hole 4 and the second hole 5 cannot penetrate either; in this way, the first hole 4 and the second hole 5 are superimposed and penetrated to form an X-shaped through-hole as shown on the right side in Figure 1 the figure.

[0030] Traditional carbon dioxide lasers are used to drill X-shaped through-holes. For relatively thick circuit boards, it is relatively simple and mature (the ratio of hole diameter to hole depth is small, and there are also problems such as easy drilling blockage at the waist of the X-shaped through-holes, which is also a pain point in the industry). However, it is very difficult to process X-shaped through-holes on relatively thin circuit boards. As Figure 2 shown, the carbon dioxide laser drills a first hole 4 that penetrates the entire circuit board on the first conductive layer 1, and the carbon dioxide laser drills a second hole 5 that penetrates the entire circuit board on the second conductive layer 3. The first hole 4 and the second hole 5 are superimposed and penetrated to form a through-hole as shown on the Figure 2 right side. At this time, because the circuit board is too thin, the first hole 4 and the second hole 5 overlap too much in the direction perpendicular to the surface of the circuit board. The final through-hole processed in this way does not have the typical characteristic of a wide hole opening and a thin waist, but almost forms a straight through-hole. If it is not required that the first hole 4 and the second hole 5 overlap too much in the direction perpendicular to the surface of the circuit board, the process parameters such as the energy and time of the laser action can be reduced. Although an X-shaped hole can be drilled, because the energy and time of the laser action are both on the lower limit, and the upper and lower conductive layers are thinned and / or the brownification is uneven, and the intermediate medium is also uneven, it is very easy for some holes to have a too thick waist, some holes to be blocked at the waist, and even the upper and lower holes are not connected.

[0031] To solve the above problems, the technical solution provided by the present invention is as follows:

[0032] Example 1:

[0033] A method for drilling an X-shaped through-hole in a circuit board uses a first laser beam and a second laser beam to drill the circuit board to fabricate a similar X-shaped through-hole; both the first laser beam and the second laser beam are non-carbon dioxide laser beams; the circuit board at least includes an insulating layer and a first conductive layer and a second conductive layer respectively attached to two surfaces of the insulating layer, and the thickness of the circuit board is less than 200 microns; as Figure 3 shown, the method for drilling an X-shaped through-hole in a circuit board includes:

[0034] The first step is to use the first laser beam to drill at a preset position on the first conductive layer to penetrate the first conductive layer but not the insulating layer to form a first hole.

[0035] The second step is to use the first laser beam to drill at a position on the second conductive layer opposite to the first hole to penetrate the second conductive layer but not communicate with or be critically connected to the first hole to form a second hole; wherein, the size of the second hole matches the size of the first hole.

[0036] Alternatively, use the second laser beam to drill the insulating layer at the bottom of the first drill hole without penetrating the insulating layer to form a third drill hole; wherein, the orifice size of the third drill hole is less than half of the orifice size of the first drill hole.

[0037] In the third step, when the second drill hole is formed in the second step, use the second laser beam to drill the insulating layer at the bottom of the first drill hole or the second drill hole to form a third drill hole that connects the first drill hole and the second drill hole; wherein, the orifice size of the third drill hole is less than half of the orifice size of the first drill hole or the second drill hole; thereby, the first drill hole, the second drill hole, and the third drill hole combine to form a quasi-X-shaped through hole on the circuit board.

[0038] When the third drill hole is formed in the second step, use the first laser beam to drill at a position on the second conductive layer opposite to the first drill hole to form a second drill hole that communicates with the third drill hole; wherein, the size of the second drill hole matches the size of the first drill hole; thereby, the first drill hole, the second drill hole, and the third drill hole combine to form a quasi-X-shaped through hole on the circuit board.

[0039] Wherein:

[0040] The "matching" in that the size of the second drill hole matches the size of the first drill hole means that the size of the second drill hole is the same as or substantially the same as the size of the first drill hole, and being substantially the same means that the size deviation between the two is within a preset range.

[0041] The critical conduction means that the first drill hole and the second drill hole are conducted, but the size of the overlapping hole formed when the two are conducted is less than the size of the third drill hole. When the bottom of the first drill hole just overlaps with the bottom of the second drill hole, the two bottoms are conducted, but the size of the through hole is less than the size of the third drill hole, which does not meet the requirements of subsequent electroplating filling. In order to ensure that the connectivity of the first drill hole and the second drill hole meets the requirements of subsequent electroplating filling, the present invention provides a drilling process for the third drill hole, which directly ensures the connectivity reliability of the first drill hole and the second drill hole and avoids the industry pain point of blocked holes at the waist of traditional X-shaped holes.

[0042] The core point of the present invention is: The first drill hole and the second drill hole can be described as "a strong crossbow at the end cannot penetrate thin silk". It is necessary to form a flared opening and not be too deep. Therefore, the first drill hole and the second drill hole should just be connected but not overly connected (this is a necessary condition for forming a quasi-X-shaped through hole), which is very difficult to achieve on non-uniform hard board materials; in order to ensure that the first drill hole and the second drill hole are just connected but not overly connected, the present invention provides a drilling process for the third drill hole, which directly ensures the connectivity reliability of the first drill hole and the second drill hole and avoids the industry pain point of blocked holes at the waist of traditional X-shaped holes.

[0043] To further illustrate the method of the present invention, the following embodiments are provided, as Figure 4 shown below:

[0044] The thickness of the circuit board is less than 100 microns, and it at least includes an insulating layer 2 and a first conductive layer 1 and a second conductive layer 3 respectively attached to the two surfaces of the insulating layer 2. The thicknesses of the first conductive layer 1 and the second conductive layer 3 are only a few microns. A first laser beam (not marked in the figure, not a carbon dioxide laser beam) is used to drill a first trumpet-shaped hole 4 on the first conductive layer 1, and a first laser beam is used to drill a second trumpet-shaped hole 5 on the second conductive layer 3. The horizontal deviation of the axes of the first hole 4 and the second hole 5 does not exceed 30 microns. In the direction perpendicular to the surface of the circuit board, the bottom spacing between the first hole 4 and the second hole 5 is less than 50 microns and is not conductive in principle. In this way, when processing the first hole 4 and the second hole 5, there is no need to consider the conduction problem between the first hole 4 and the second hole 5, and only the processing problems of the first hole 4 and the second hole 5 themselves need to be considered. Therefore, even if the first conductive layer 1 and the second conductive layer 3 are uneven, and / or the medium of the insulating layer 2 is uneven, it only affects the depths of the first hole 4 and the second hole 5, and does not involve the conduction problem between the two holes, that is, conduction is acceptable and non-conduction is also acceptable. For the conduction problem between the two holes, the present invention introduces a second laser beam (not marked in the figure), which is specifically used to connect the first hole 4 and the second hole 5 to form a straight cylindrical third hole 6. The first hole 4, the second hole 5, and the third hole 6 are superimposed and combined to finally form a Figure 4 class X-shaped through hole as described on the right side.

[0045] Figure 5 is shown on the Figure 4 basis as a schematic diagram of the circuit board material. The second laser beam processes the third hole 6, thoroughly ensuring the connection problem between the first hole 4 and the second hole 5, overcoming the problem of unevenness of the circuit board material 7 (conductive layer and insulating layer), and also forming a class X-shaped through hole, which is very beneficial for electroplating filling. During electroplating filling, the third hole 6 located at the waist of the X-shaped through hole is filled with electroplating first. Since the first hole 4 and the second hole 5 are shallow in depth and wide in width, electroplating filling is very easy.

[0046] The method of the present invention has the following advantages: The present invention uses a first laser beam to fabricate the first drill hole and the second drill hole, without considering the issue of whether the first drill hole and the second drill hole are reliably connected, overcoming the influence on the uniformity of the circuit board material and the machining depths of the first drill hole and the second drill hole; The present invention uses a second laser beam to perform the connection and through-hole machining of the first drill hole and the second drill hole, obtaining a third drill hole with a smaller size, thereby achieving the effect of a quasi-X-shaped through hole: a smaller waist hole diameter, which is very beneficial for subsequent electroplating filling, and also makes the machining of the quasi-X-shaped through hole of a thin circuit board (such as a thin rigid board) reliable and simple, solving the pain points of the industry.

[0047] To further illustrate the method of the present invention, there are the following embodiments, as Figure 5 shown:

[0048] Materials: The first conductive layer 1 is a copper layer with a thickness of 3 microns; the insulating layer 2 is a BT material layer with a thickness of 65 microns, which is copolymerized from bismaleimide (BMI) and triazine resin (T) and contains glass fibers; the third conductive layer 3 is a copper layer with a thickness of 3 microns.

[0049] Laser and optical path: A first laser beam is used for drilling machining, laser wavelength: 532 nanometers, pulse width: 15 picoseconds, average power: 50 watts, pulse repetition frequency: 500 kilohertz, machining spot: 100 microns; A second laser beam is used for drilling machining, laser wavelength: 532 nanometers, pulse width: 15 picoseconds, average power: 50 watts, pulse repetition frequency: 500 kilohertz, machining spot: 30 microns. The first laser beam and the second laser beam are transmitted through the optical path and combined into the same galvanometer, and are focused by the same focusing flat-field lens. The galvanometer is an imported galvanometer from scanlab in Germany, with a wavelength of 532 nanometers, the focal length of the focusing flat-field lens is 100 millimeters, and the wavelength is 532 nanometers, and the material is quartz.

[0050] Processing process: The copper layers of the first conductive layer 1 and the third conductive layer 3 have a thickness of only 3 microns. A first laser beam (not marked in the figure) machines the first drill hole 4, and the first laser beam machines the second drill hole 5. The orifice sizes of the first drill hole 4 and the second drill hole 5 are 100 microns. The axial horizontal misalignment deviation between the first drill hole 4 and the second drill hole 5 does not exceed 20 microns. In the direction perpendicular to the surface of the circuit board, the bottom spacing between the first drill hole 4 and the second drill hole 5 is less than 20 microns. In principle, the first drill hole 4 and the second drill hole 5 are not conductive, and it doesn't matter if they are partially conductive. In this way, when machining the first drill hole 4 and the second drill hole 5, there is no need to consider the conduction problem between the first drill hole 4 and the second drill hole 5, and only the machining problems of the first drill hole 4 and the second drill hole 5 themselves need to be considered. In this way, even if the first conductive layer 1 and the third conductive layer 3 are uneven, and even if the medium in the insulating layer 2 is uneven, these non-uniformities only affect the depth of the first drill hole 4 and the second drill hole 5, and do not involve the conduction problem, that is, conduction is okay, and non-conduction is also okay.

[0051] The process of processing the first drill hole 4 and the second drill hole 5 is as follows: on the surface of the first conductive layer 1, the first laser beam punches holes at a preset position, with a punching power of 30 watts, 500 KHz, a punching time of 50 microseconds, an orifice diameter of 100 microns, and a hole depth of 25 microns (including a copper layer thickness of 3 microns); after all the first drill holes 4 on the first conductive layer 1 are processed, the circuit board is flipped, and the second conductive layer 3 faces the first laser beam at this time, is positioned and fixed, and the first laser beam punches holes at the corresponding position on the second conductive layer 3, with an orifice diameter of 100 microns and a hole depth of 25 microns (including a copper layer thickness of 3 microns); after each second drill hole 5 is processed, the second laser beam punches holes at the bottom of the hole of the second drill hole 5 to form a third drill hole 6, with a punching power of 30 watts, 500 KHz, a punching time of 50 microseconds, and a hole diameter of 30 microns, to complete the through-hole work with the first drill hole 4, and finally form an X-shaped through-hole as shown in Figure 5 the right figure; it is also possible that after all the second drill holes 5 are punched, the second laser beam punches and drills the bottom of each second drill hole 5 to complete the connection and through-hole action of the first drill hole 4 and the second drill hole 5. In this way, all the second drill holes 5 on the second conductive layer 3 are processed in sequence, as well as the connection and through-hole of the first drill hole 4 and the second drill hole 5. In addition, for the drilling action of connecting the first drill hole 4 and the second drill hole 5 (i.e., making the third drill hole 6), after the first laser beam processes the first drill hole 4, the second laser beam can punch holes at the bottom of the first drill hole 4. It can drill the third drill hole 6 after each first drill hole 4 is drilled, or after all the first drill holes 4 are punched, drill holes at the bottom of each first drill hole 4 one by one to form the third drill hole 6. In this embodiment, since the second laser beam drilling uses green picosecond laser, even if there is an uneven distribution of glass fibers in the insulating material, it does not affect the through-hole drilling problem of connecting the first drill hole 4 and the second drill hole 5.

[0052] The present invention introduces a second laser beam, which is specifically used for the problem of connecting and drilling the first drill hole 4 and the second drill hole 5. The finally formed X-shaped through-hole is composed of the first drill hole 4, the second drill hole 5, and the third drill hole 6. The second laser beam processing the third drill hole 6 thoroughly guarantees the connection problem of the first drill hole 4 and the second drill hole 5, overcomes the problem of unevenness of the circuit board material 9 (conductive layer and insulating layer), and also forms an X-shaped through-hole, which is very beneficial for electroplating filling. The third drill hole 6 located at the through-hole waist of the X-shaped through-hole is filled with electroplating first, and since the first drill hole 4 and the second drill hole 5 are shallow in depth and wide in width, electroplating filling is very easy.

[0053] A method for drilling an X-shaped through-hole in a circuit board of the present invention also has the following preferred solutions:

[0054] Preferably, the thicknesses of both the first conductive layer and the second conductive layer are less than 9 microns.

[0055] The thickness of the first conductive layer and the second conductive layer (surface copper) of a general circuit board is about 3 to 6 microns, which is determined by the line width of the fine circuit on the circuit board. If the copper surface is too thick, it is impossible to etch a circuit with too fine line width and line pitch.

[0056] Preferably, the linear distance between the bottoms of the first drill hole and the second drill hole is less than 50 microns.

[0057] Due to the small diameter of the third drill hole, the depth of the third drill hole should not be too large.

[0058] Preferably, the first laser beam is a Gaussian beam, and the diameter of the processing spot of the first laser beam is less than 100 microns; the second laser beam is a Gaussian beam, and the diameter of the processing spot of the second laser beam is less than 50 microns.

[0059] Preferably, the error between the central axes of the first drill hole and the second drill hole is less than 30 microns.

[0060] The error between the central axes of the first drill hole and the second drill hole being less than 30 microns can ensure the subsequent penetration of the first drill hole and the second drill hole.

[0061] Preferably, the insulating layer is composed of a single insulating material, or is composed of a stack of multiple different single insulating materials, or is composed of a mixture of multiple different insulating materials; the materials of the first conductive layer and the second conductive layer are any one or a combination of multiple of copper, aluminum, gold, silver, nickel, chromium, beryllium, and titanium.

[0062] A relatively typical case is that the conductive material is copper and the insulating material is a mixture of a polymer material and glass fiber.

[0063] Preferably, the first laser beam is an ultrafast laser beam; the second laser beam is a nanosecond laser beam or a sub-nanosecond laser beam or an ultrafast laser beam.

[0064] Since many of the insulating materials of the carrier board contain glass fiber, the first laser beam is preferably an ultrafast laser; for the drilling process of the third drill hole, since the laser is in a focused state, a focused nanosecond laser, sub-nanosecond laser, or ultrafast laser can all perform well in processing. The ultrafast laser includes lasers with very short pulse widths such as picosecond lasers and femtosecond lasers.

[0065] Preferably, the first laser beam is an independent laser beam, or is obtained by deflecting and scanning the second laser beam.

[0066] For example, the second laser beam is deflected and scanned by a two-dimensional acousto-optic deflector to drill the first and second holes; that is, the second laser beam can achieve the function of the first laser beam through deflection scanning. When the acousto-optic deflector stops scanning, the second laser beam directly punches to make the third hole, or the acousto-optic deflector scans with a smaller scanning radius to make the third hole.

[0067] Preferably, the processing spots of the first laser beam and the second laser beam are respectively obtained by scanning and focusing the first laser beam and the second laser beam through the same set of scanning galvanometers and flat-field focusing lenses; the center distance between the processing spot of the first laser beam and the processing spot of the second laser beam is less than 40 millimeters.

[0068] The drilling of the circuit board by the laser beam is to irradiate the surface of the circuit board to form a processing spot after the laser beam is transmitted and transformed by the laser optical path, and the processing spot drills holes on the circuit board.

[0069] The smaller the distance between the centers of the processing spots of the first laser beam and the second laser beam, the shorter the movement time for the second laser beam to align with the bottom of the first or second hole after the processing of the first or second hole is completed, and the higher the processing efficiency of the third hole. In addition, since it is the same set of galvanometers and the same Z-axis coordinate height, during the processing of the first, second, and third holes, there is no displacement change between the flat-field focusing lens and the circuit board. Therefore, this is completed within one coordinate system, and the switching accuracy between the processing spots of the first laser beam and the second laser beam is very high and stable. Specifically, the first laser beam and the second laser beam can be combined and enter the same set of scanning galvanometer and flat-field focusing lens system, or they can enter the same set of scanning galvanometer and flat-field focusing lens system in a non-combined manner.

[0070] Preferably, the processing spots of the first laser beam and the second laser beam are obtained by two different laser beams passing through different external optical paths and different focusing systems, or by two different laser beams passing through different external optical paths and the same focusing system, or by the same beam of light dynamically adjusting the size of the processing spot through a dynamic focusing system; or by the same beam of light passing through different external optical paths but through the same focusing system.

[0071] The above several situations are different:

[0072] The processing spots of the first laser beam and the second laser beam are obtained by two different laser beams passing through different external optical paths and different focusing systems. This situation includes two sets of galvanometers and two sets of focusing lenses corresponding to two laser beams on one processing platform.

[0073] The processing spot of the first laser beam and the processing spot of the second laser beam are obtained by two different laser beams passing through different external optical paths and the same focusing system. This situation is that two laser beams pass through two sets of galvanometers and finally enter the same set of flat-field focusing mirrors. Some galvanometers seem to be one galvanometer, but inside there are two sets of two-dimensional galvanometers integrated into one galvanometer housing, that is, one laser beam corresponds to an XY galvanometer, and two sets of XY two-axis galvanometers are integrated into one housing;

[0074] The processing spot of the first laser beam and the processing spot of the second laser beam are obtained by dynamically adjusting the size of the processing spot of the same beam of light through a dynamic focusing system. Defocusing is the processing spot of the first laser beam, and positive focusing is the processing spot of the second laser beam;

[0075] The processing spot of the first laser beam and the processing spot of the second laser beam are obtained by the same beam of light passing through different external optical paths and switching but passing through the same focusing system. In this case, after a laser beam passes through an optical switch and switches to different external optical paths, it is focused by the same flat-field focusing mirror, and different processing spots on the processing table can be obtained. To use a certain laser processing spot, only need to switch the laser beam to the corresponding external optical path branch.

[0076] Preferably, the processing spot of the first laser beam is a defocused and focused spot of a Gaussian beam, and the

[0077] processing spot of the second laser beam is a positively focused spot of a Gaussian beam.

[0078] Preferably, the form of drilling of the first laser beam and / or the second laser beam is punching or scanning.

[0079] For the punching, the laser beam is stationary relative to the object to be processed.

[0080] Preferably, the first drilling and the second drilling are flare holes or concave holes, and the form of drilling of the first laser beam is rotary cutting or shaping punching or defocus punching or positive focus punching to form the flare hole or concave hole.

[0081] The design of the concave hole is similar to that of the flare hole. The first drilling and the second drilling in the form of concave holes are connected by a third drilling with a smaller size to form a quasi-X-shaped through hole, which is also convenient for electroplating to fill the hole and preferentially fill the waist of the quasi-X-shaped through hole. The surface concave hole is beneficial to filling and plating the surface shallow hole. The smaller in the smaller size of the third drilling is relative to the size of the first drilling and the second drilling in the form of concave holes. Generally, the size of the third drilling is less than half of the size of the first drilling.

[0082] Specifically, as Figure 6 shown:

[0083] Materials: The first conductive layer 1 is a copper layer with a thickness of 6 microns; the insulating layer 2 is a BT material layer with a thickness of 65 microns, which is copolymerized from bismaleimide (BMI) and triazine resin (T) and contains glass fibers; the second conductive layer 3 is a copper layer with a thickness of 6 microns.

[0084] Laser and optical path: The second laser beam is used and undergoes rotary cutting and scanning through an acousto-optic deflection scanning system to form the first drilling hole 4 and the second drilling hole 5 in the form of concave holes (the second laser beam realizes the function of the first laser beam through deflection scanning). Laser wavelength: 532 nm, pulse width: 15 picoseconds, average power: 30 W, pulse repetition frequency: 200 kHz; the second laser beam is used to perform small-amplitude scanning processing through the acousto-optic deflection scanning system to form the third drilling hole 6, or the acousto-optic deflection system does not scan for punching processing to form the third drilling hole 6. The beam output by the acousto-optic deflection scanning system is incident on a galvanometer system and is focused by a flat-field focusing lens. The galvanometer is an imported galvanometer from scanlab in Germany, with a wavelength of 532 nm, a focal length of 100 mm for the flat-field focusing lens, and a wavelength of 532 nm, made of quartz.

[0085] Processing procedure: As Figure 6As shown, the copper layer thickness of the first conductive layer 1 and the second conductive layer 3 is 6 microns. The orifice sizes of the first drill hole 4 and the second drill hole 5 in the form of concave holes are 100 microns, and both are circular concave holes. Of course, square concave holes can also be processed. The deviation of the central axes of the first drill hole 4 and the second drill hole 5 does not exceed 20 microns, and the linear distance between the bottoms of the first drill hole 4 and the second drill hole 5 is less than 40 microns and greater than 20 microns. In this way, when processing the first drill hole 4 and the second drill hole 5, there is no need to consider the processing depth of the first drill hole 4 and the second drill hole 5. Therefore, even if the first conductive layer 1 and the second conductive layer 3 are uneven, and even if the medium of the insulating layer 2 is uneven, these non-uniformities only affect the depth of the first drill hole 4 and the second drill hole 5. The process of processing the first drill hole 4 and the second drill hole 5 in the form of concave holes in this embodiment is as follows: Using the second laser beam, through the acousto-optic deflection scanning system (not marked in the figure), perform concave hole rotary cutting and scanning to form the first drill hole 4. The scanning laser power is 15 watts, the laser pulse repetition frequency is 200KHz, the orifice diameter of the first drill hole 4 is 100 microns, and the depth is 25 microns (including 6 microns of copper at the back). After all the first drill holes on the first conductive layer 1 are processed, flip the circuit board so that the second conductive layer 3 faces the laser beam, position and fix it. The second laser beam scans and processes at the corresponding position of the second conductive layer 3 under the control of the acousto-optic deflection system or the galvanometer control to form the second drill hole 5. The orifice diameter of the second drill hole 5 is 100 microns, and the hole depth is 25 microns (including the copper layer thickness of 6 microns). After each second drill hole 5 is processed, the second laser beam performs a small-scale scanning or punching process at the bottom of the second drill hole 5 (at this time, the scanning process can be galvanometer scanning or acousto-optic deflection system scanning) to form the third drill hole 6. The laser power is 15 watts, 200KHz. If it is punching, the punching time is 50 microseconds, and the hole diameter is 30 microns to complete the through-hole work with the first drill hole 4 and the second drill hole 5, and finally form a through-hole similar to an X shape as shown on the Figure 6 right side; it is also possible to, after all the second drill holes 5 are processed, the second laser beam performs punching or scanning drilling on the bottom of each second drill hole 5 to complete the through-hole work of the first drill hole 4 and the second drill hole 5, and in this way, complete the processing of all the second drill holes 5 and the connection and through-hole of the first drill hole 4 and the second drill hole 5 on the second conductive layer 3 in sequence. In addition, when processing the third drill hole 6, it is also possible to, during the process of processing the first drill hole, use the second laser beam to punch or scan the bottom of the first drill hole. It is possible to process the third drill hole 6 after each first drill hole 4 is drilled, or it is also possible to process the third drill hole 6 at the bottom of each first drill hole 4 one by one after all the first drill holes 4 are processed. In this embodiment, since the second laser beam uses green picosecond laser, the non-uniform distribution of glass fibers in the insulating material does not affect the through-hole drilling problem of the connection between the first drill hole 4 and the second drill hole 5.

[0086] In this embodiment, the first drilling hole 4 and the second drilling hole 5 can also be formed by directly impacting the surface of the circuit board with an independent first laser beam after laser beam shaping. Preferably, before the first step, the circuit board is adjusted, fixed and positioned so that a preset position on the first conductive layer faces the first laser beam;

[0087] When forming the second drilling hole in the second step, before the second step, it further includes: adjusting, fixing and positioning the circuit board so that a position on the second conductive layer opposite to the first drilling hole faces the first laser beam.

[0088] The X-shaped through holes of the circuit board need to be drilled by laser in opposite directions. The so-called drilling in opposite directions means that on the circuit board, a conical hole is processed on one side by laser, and a conical hole is processed at the same position on the other side. The two conical holes are opposed and conduct; it is very difficult to align using different devices, so generally the same device is used. First, the front side is processed, and then the back side is processed. Therefore, there is an operation process of turning over, positioning and fixing the circuit board.

[0089] Preferably, if there are multiple X-shaped through holes made on the circuit board, during the process of using the first laser beam to drill holes in the first conductive layer and the second conductive layer, first use the first laser beam to process multiple first drilling holes on the first conductive layer. After multiple first drilling holes are processed, then use the first laser beam to process multiple second drilling holes on the second conductive layer.

[0090] Generally, the number of X-shaped through holes required in a circuit board is huge, ranging from tens of thousands to hundreds of thousands or even millions of holes. Generally, all the first drilling holes are processed first, and then all the second drilling holes are processed.

[0091] Preferably, before using the first laser beam to process the first drilling hole or / and the second drilling hole, it further includes using the second laser beam to perform laser etching on the first conductive layer or / and the second conductive layer to form the orifice of the first drilling hole or the orifice of the second drilling hole.

[0092] For the case where the conductive layer is too thick and it is difficult for the first laser beam to efficiently penetrate the surface conductive layer material, since the first laser has a small focused spot, it can easily cut the surface conductive layer material by rotation.

[0093] Embodiment 2:

[0094] The present invention provides a drilling device for X-shaped through holes of a circuit board, including:

[0095] A laser for generating a first laser beam and a second laser beam, and both the first laser beam and the second laser beam are non-carbon dioxide laser beams;

[0096] A galvanometer scanning and flat-field focusing device, which is connected to the laser, is used to scan and focus the first laser beam and the second laser beam to output the processing spots of the first laser beam and the second laser beam; wherein, the light intensity distribution of the processing spot of the first laser beam is stronger in the central region than in the edge region, and the size of the processing spot of the second laser beam is less than one-half of the size of the processing spot of the first laser beam;

[0097] A controller, which is connected to the galvanometer scanning and flat-field focusing device, is used to control the first laser beam and the second laser beam to perform the X-shaped through-hole drilling method for circuit boards as described above.

[0098] Preferably, the controller controls the flat-field focusing and galvanometer scanning device in the same coordinate system to drill holes with the first laser beam and the second laser beam, or controls the flat-field focusing and galvanometer scanning device in different coordinate systems to laser drill holes with the first laser beam and the second laser beam.

[0099] Embodiment 3:

[0100] The present invention provides an X-shaped through-hole drilling device for circuit boards, including a processor, a memory, and a computer program stored in the memory. When the computer program is executed by the processor, it implements the X-shaped through-hole drilling method for circuit boards as described above.

[0101] Embodiment 4:

[0102] The present invention provides an X-shaped through-hole drilling system for circuit boards, including a machine table, and further including the X-shaped through-hole drilling device for circuit boards and the X-shaped through-hole drilling device for circuit boards as described above. The X-shaped through-hole drilling device for circuit boards is electrically connected to the X-shaped through-hole drilling device for circuit boards;

[0103] The machine table is used to carry the circuit board;

[0104] The X-shaped through-hole drilling device for circuit boards is used to control the X-shaped through-hole drilling device for circuit boards to perform the X-shaped through-hole drilling method for circuit boards as described above to drill holes in the circuit board carried on the machine table.

[0105] In a method, device, apparatus and system for drilling X-shaped through holes in a circuit board according to the present invention, a first laser beam is used to respectively produce a first drill hole and a second drill hole on two opposite sides of the circuit board, and a second laser beam is used to produce a third drill hole with a size smaller than the first drill hole and the second drill hole. The third drill hole connects the first drill hole and the second drill hole, thereby forming an X-shaped through hole on the circuit board, solving the industry pain points that occur in the production of X-shaped through holes in the prior art; in addition, since the laser beam used is no longer a carbon dioxide laser beam, it is not necessary to perform a brownification treatment on the surface of the circuit board, saving the production process.

[0106] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A drilling method for X-shaped through holes in circuit boards, characterized in that, Drilling processing is performed on a circuit board using a first laser beam and a second laser beam to fabricate a quasi-X-shaped through hole; both the first laser beam and the second laser beam are non-carbon dioxide laser beams; the circuit board at least includes an insulating layer and a first conductive layer and a second conductive layer respectively attached to two surfaces of the insulating layer, and the thickness of the circuit board is less than 200 microns; The drilling method for the quasi-X-shaped through hole of the circuit board includes: In the first step, drilling processing is performed using the first laser beam at a preset position on the first conductive layer to penetrate the first conductive layer but not the insulating layer, forming a first drill hole; In the second step, drilling processing is performed using the first laser beam at a position on the second conductive layer opposite to the first drill hole to penetrate the second conductive layer but not communicate with or critically communicate with the first drill hole, forming a second drill hole; wherein, the size of the second drill hole matches the size of the first drill hole; Or, drilling processing is performed using the second laser beam at the bottom of the first drill hole on the insulating layer without penetrating the insulating layer, forming a third drill hole; wherein, the orifice size of the third drill hole is less than half of the orifice size of the first drill hole; In the third step, when the second drill hole is formed in the second step, then drilling processing is performed using the second laser beam at the bottom of the first drill hole or the second drill hole on the insulating layer to communicate the first drill hole with the second drill hole, forming a third drill hole; wherein, the orifice size of the third drill hole is less than half of the orifice size of the first drill hole or the second drill hole; thereby, the first drill hole, the second drill hole, and the third drill hole are combined to form a quasi-X-shaped through hole on the circuit board; When the third drill hole is formed in the second step, then drilling processing is performed using the first laser beam at a position on the second conductive layer opposite to the first drill hole to communicate with the third drill hole, forming a second drill hole; wherein, the size of the second drill hole matches the size of the first drill hole; thereby, the first drill hole, the second drill hole, and the third drill hole are combined to form a quasi-X-shaped through hole on the circuit board.

2. The method for drilling X-shaped through holes in circuit boards according to claim 1, wherein The thicknesses of both the first conductive layer and the second conductive layer are less than 9 microns.

3. The method for drilling X-shaped through holes in circuit boards according to claim 1, characterized in that The linear distance between the bottoms of the first drill hole and the second drill hole is less than 50 microns.

4. The method for drilling X-shaped through holes in circuit boards according to claim 1, characterized in that, The first laser beam is a Gaussian beam, and the processing spot diameter of the first laser beam is less than 100 microns; the second laser beam is a Gaussian beam, and the processing spot diameter of the second laser beam is less than 50 microns.

5. The method for drilling X-shaped through holes in circuit boards according to claim 1, wherein The error between the central axes of the first drill hole and the second drill hole is less than 30 microns.

6. The method for drilling X-shaped through holes in circuit boards according to claim 1, characterized in that The insulating layer is composed of a single insulating material, or is composed of a stack of multiple different single insulating materials, or is composed of a mixture of multiple different insulating materials; the materials of the first conductive layer and the second conductive layer are any one or a combination of multiple of copper, aluminum, gold, silver, nickel, chromium, beryllium, and titanium.

7. The method for drilling X-shaped through holes in circuit boards according to claim 1, characterized in that, The first laser beam is an ultrafast laser beam; the second laser beam is a nanosecond laser beam or a sub-nanosecond laser beam or an ultrafast laser beam.

8. The method for drilling X-shaped through holes in circuit boards according to claim 1, wherein The first laser beam is an independent laser beam, or is obtained by deflecting and scanning the second laser beam.

9. The method for drilling X-shaped through holes in circuit boards according to claim 1, wherein, The processing spot of the first laser beam and the processing spot of the second laser beam are respectively obtained by scanning and focusing the first laser beam and the second laser beam through the same set of galvanometric scanners and flat-field focusing lenses; the center distance between the processing spot of the first laser beam and the processing spot of the second laser beam is less than 40 millimeters.

10. The method for drilling X-shaped through holes in circuit boards according to claim 1, characterized in that, The processing spot of the first laser beam and the processing spot of the second laser beam are obtained by two different laser beams passing through different external optical paths through different focusing systems, or by two different laser beams passing through different external optical paths through the same focusing system, or by the same laser beam passing through a dynamic focusing system to dynamically adjust the size of the processing spot; or by the same laser beam passing through different external optical paths but passing through the same focusing system.

11. The method for drilling X-shaped through holes in a circuit board according to claim 9 or 10, characterized in that, The processing spot of the first laser beam is a defocused Gaussian beam focusing spot, and the processing spot of the second laser beam is a focused Gaussian beam focusing spot.

12. The method for drilling X-shaped through holes on a circuit board according to claim 1, characterized in that, The form of drilling by the first laser beam and / or the second laser beam is punching or scanning.

13. The method for drilling X-shaped through holes in circuit boards according to claim 1, characterized in that, The first drill hole and the second drill hole are flare holes or concave holes, and the form of drilling by the first laser beam is rotary cutting, shaping punching, defocused punching or focused punching to form the flare hole or the concave hole.

14. The method for drilling X-shaped through holes in circuit boards according to claim 1, wherein Before the first step, it further includes adjusting, fixing and positioning the circuit board so that the preset position on the first conductive layer faces the first laser beam; When the second drill hole is formed in the second step, before the second step, it further includes: adjusting, fixing and positioning the circuit board so that the position on the second conductive layer opposite to the first drill hole faces the first laser beam.

15. The method for drilling X-shaped through holes in circuit boards according to claim 1, characterized in that, If there are multiple X-shaped through holes made on the circuit board, during the process of drilling the first conductive layer and the second conductive layer with the first laser beam, first use the first laser beam to process multiple first drill holes on the first conductive layer, and when multiple first drill holes are processed, then use the first laser beam to process multiple second drill holes on the second conductive layer.

16. The method for drilling X-shaped through holes in circuit boards according to claim 1, characterized in that, Before using the first laser beam to process the first drill hole or / and the second drill hole, it further includes using the second laser beam to laser-etch the first conductive layer or / and the second conductive layer to form the hole opening of the first drill hole or the hole opening of the second drill hole.

17. A drilling device for X-shaped through holes in circuit boards, characterized in that, It includes: A laser for generating a first laser beam and a second laser beam, both the first laser beam and the second laser beam being non-carbon dioxide laser beams; A galvanometric scanning and flat-field focusing device connected to the laser for scanning and focusing the first laser beam and the second laser beam to output the processing spot of the first laser beam and the processing spot of the second laser beam; wherein, the light intensity distribution of the processing spot of the first laser beam is stronger in the central region than in the edge region, and the size of the processing spot of the second laser beam is less than one-half of the size of the processing spot of the first laser beam; A controller connected to the galvanometric scanning and flat-field focusing device for controlling the first laser beam and the second laser beam to execute the method for drilling X-shaped through holes on a circuit board according to any one of claims 1 to 16.

18. The circuit board type X-shaped through hole drilling device according to claim 17, characterized in that, The controller controls the flat-field focusing and galvanometer scanning device in the same coordinate system to perform drilling on the first laser beam and the second laser beam, or controls the flat-field focusing and galvanometer scanning device in different coordinate systems to perform laser drilling on the first laser beam and the second laser beam.

19. A drilling device for X-shaped through holes in circuit boards, characterized in that, It includes a processor, a memory, and a computer program stored in the memory. When the computer program is executed by the processor, it implements the method for drilling X-shaped through holes in circuit boards according to any one of claims 1 to 16.

20. A drilling system for X-shaped through holes in circuit boards, characterized in that, It includes a machine table, and also includes the circuit board X-shaped through hole drilling equipment according to claim 17 or 18 and the circuit board X-shaped through hole drilling device according to claim 19. The circuit board X-shaped through hole drilling device is electrically connected to the circuit board X-shaped through hole drilling equipment; The machine table is used to carry the circuit board; The circuit board X-shaped through hole drilling device is used to control the circuit board X-shaped through hole drilling equipment to execute the method for drilling X-shaped through holes in circuit boards according to any one of claims 1 to 16 to perform drilling on the circuit board carried on the machine table.

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