Laser processing method of printed board and laser processing machine of printed board

Abstract

Provided is a laser processing method for a printed board and a laser processing machine for a printed board, which can fully utilize the capacity of a laser oscillator, and which can improve the processing quality and the processing efficiency by making the energy of the laser supplied to the processing portion uniform. The laser processing method for a printed board is a method for processing a workpiece by irradiating the workpiece with a beam from a laser oscillator controlled by a high-frequency pulse RF, wherein, from the start of the processing to the end of the processing, if the high-frequency pulse RF is not activated for a predetermined time, the high-frequency pulse RF is repeatedly activated at predetermined intervals, and the output beam is made to impinge on a damper for absorbing the energy of the beam.

Description

Technical Field

[0001] This invention relates to a laser processing method for a printed circuit board and a laser processing machine for the printed circuit board. The printed circuit board is a composite printed circuit board, wherein an insulating layer formed of resin containing glass fiber or filler is sandwiched between a surface copper layer and a lower copper layer. The laser processing method involves forming blind vias (non-through holes, hereinafter referred to as recessed vias or BH) on the printed circuit board to connect the surface copper layer and the lower copper layer, or processing the front and back sides of both substrates to form through holes (hereinafter referred to as through holes or TH) to connect the front copper layer and the back copper layer. Background Technology

[0002] First, let's explain the structure of existing laser processing machines.

[0003] Figure 5 This is a structural diagram of an existing laser processing machine.

[0004] Laser oscillator 1 outputs a pulsed linearly polarized laser beam 2 (hereinafter referred to as "beam 2").

[0005] The beam diameter adjustment device 3, located between the laser oscillator 1 and the plate 6, is used to adjust the energy density of the laser beam 2. By changing the outer diameter of the beam 2, the energy density of the laser is adjusted. That is, the energy of the beam 2 remains unchanged before and after the beam diameter adjustment device 3; therefore, the beam 2 emitted from the beam diameter adjustment device 3 can be considered as the beam 2 output from the laser oscillator 1. Therefore, the laser oscillator 1 and the beam diameter adjustment device 3 are collectively referred to as the laser output device 1A below. Alternatively, the beam diameter adjustment device 3 may not be used. A polarization conversion device 4 is located between the beam diameter adjustment device 3 and the plate 6. The polarization conversion device 4 converts the linearly polarized beam 2 into a circularly polarized beam 5. Furthermore, the polarization conversion device 4 has a reflection shielding mechanism (since this mechanism is well-known in the industry, it will not be described in detail here), which shields the beam 5 reflected from the processing section during processing, thus preventing damage to the laser oscillator 1 from the beam 5 reflected from the processing section. The plate 6, positioned between the polarizer 4 and the galvanometer mirror 7a, is made of a material (e.g., copper) through which the light beam 5 cannot pass, and has multiple selectable apertures 8 (a type of window, here a circular through-hole) formed at predetermined positions. The plate 6 is driven by a drive device (omitted in the figure) to position the axis of the selected aperture 8 coaxial with the axis of the light beam 5.

[0006] The galvanometer device 7, as shown by the arrow in the figure, is composed of two galvanometer reflectors 7a and 7b, whose rotation axes are orthogonal to each other, allowing the reflecting surface to be positioned at any angle. The galvanometer reflectors 7a and 7b, together with the fθ lens 9, form an optical axis positioning mechanism C, which positions the optical axis of the beam 5 at the desired position on the printed circuit board 10. The optical axis positioning mechanism C is supported by a support frame 30, allowing it to be freely positioned relative to the processing head (not shown) in the vertical direction Z. The processing area 11, determined by the rotation angles of the galvanometer reflectors 7a and 7b and the diameter of the fθ lens 9, is approximately 50mm x 50mm in size. A hood 40 surrounds the area below the fθ lens 9 and the area above the desired processing area 11, and is supported so that it can be freely positioned relative to the support frame 30 supporting the optical axis positioning mechanism C in the vertical direction Z. An attraction device (not shown) is connected inside the hood. Furthermore, the mask 40 is positioned before processing, with its lower end positioned at a predetermined gap with the surface of the printed circuit board 10. This reduces the amount of particles or spatter such as copper or insulation generated during processing adhering to the fθ lens 9 or the surface of the printed circuit board 10. The printed circuit board 10, as the workpiece, is fixed on an XY stage 12 extending along directions X and Y that are perpendicular to and intersect with the vertical direction Z. The control device 20 controls the operation of the laser oscillator 1, the beam diameter adjustment device 3, the drive device of the plate 6, the galvanometer reflectors 7a and 7b, and the XY stage 12 according to the input control program.

[0007] See Figure 5 and Figure 6 , Figure 6 This is a diagram showing the processing area 11 in the printed circuit board 10 and an example of the processing sequence.

[0008] Taking this printed circuit board 10 as an example, multiple processing areas 11 are divided into processing areas 1101 to 1112, arranged in 3 columns in the X direction and divided into 4 segments in the Y direction. When processing recessed holes, the XY stage 12 is moved so that the fθ lens 9 faces any one of the designated processing areas 1101 to 1112. First, the copper layer of all the recessed holes in this processing area is irradiated with a beam of light once (that is, a pulse beam 5 is irradiated, the irradiation time, i.e., the pulse width is, for example, 15 μs) to process the recessed holes (the recessed holes formed on the copper layer are called windows). Then, by irradiating a single or multiple beams of light (with a pulse width of, for example, 15 μs), the insulating layer below the window is processed to complete the recessed holes in this processing area. In addition, processing usually starts from the processing area 1101 at the left end of the figure and is performed in the order shown by arrow R in the figure, and finally ends at the processing area 1112.

[0009] Furthermore, the laser oscillator 1 is a device that outputs laser light by oscillating its internal laser medium when a high-frequency pulse RF is input. The laser output is controlled by the opening and closing of the input high-frequency pulse RF. That is, the laser oscillates when the high-frequency pulse RF is started and stops oscillating when the high-frequency pulse RF is stopped. If the oscillation frequency of the laser oscillator 1 is 10kHz, then the pulse period is 100μs.

[0010] However, if the laser oscillator 1 is a carbon dioxide laser oscillator, the output will be unstable during the period after the laser oscillator 1 is started, until the energy accumulated in the laser medium reaches a certain value (hereinafter referred to as the "stabilization period at startup"). Moreover, even after the laser oscillator 1 is started, for example, if the XY stage 12 moves between the processing areas 11, the laser beam 5 is not irradiated during the movement period, so the interval of laser oscillation becomes longer as the movement time increases, which may cause the output of the laser beam 5 to be unstable. In order to stabilize the beam output under such conditions, the magnitude of the high-frequency pulse RF input to the laser oscillator 1 is set to a magnitude that is not large enough to output laser light (this state is called the simmer state) to ensure that a stable output can be obtained at the start of processing. In this way, even immediately after the laser power supply is turned on or immediately after the XY stage 12 moves, a concave hole with a practical diameter can be processed.

[0011] Here, the stabilization period during startup is approximately 5 seconds (5000 ms). Furthermore, the movement time required for the XY stage 12 to move from one processing area to the next is over 200 ms. However, if the laser oscillation interval is less than 20 ms, the output of the laser oscillator will not decrease.

[0012] As for the pulse frequency, if the concave hole is being machined in the machining area 11, it is usually 2 to 3 kHz (that is, the average time of the pulse interval is 0.3 to 0.5 ms).

[0013] The problem that the invention aims to solve:

[0014] As described above, apart from the stabilization period at startup, if the movement time required for the XY stage 12 to move the processing area 11 is long, then by putting the laser oscillator 1 into a pre-burning state, it is possible to process a concave hole with a diameter of 50 μm at a pulse frequency of less than 3.5 kHz when processing a copper layer with a thickness of 2 μm, and achieve a practical concave hole processing result.

[0015] However, if processing is performed at a pulse frequency of 3.5kHz or higher, the diameter of the processed concave hole will be more than 5% smaller than the diameter of the target concave hole. Therefore, simply putting the laser oscillator 1 into a pre-ignition state is insufficient to fully utilize the capabilities of the laser oscillator 1, and cannot improve processing quality and efficiency. Summary of the Invention

[0016] The purpose of this invention is to provide a laser processing method and a laser processing machine for printed circuit boards, which can fully utilize the capabilities of the laser oscillator and make the beam pattern (energy distribution in the beam path direction, i.e., output distribution) of the laser supplied to the processing unit uniform, thereby improving processing quality and processing efficiency.

[0017] To investigate the reason why the diameter of the machined concave hole decreases after the pre-ignition state ends, the inventors conducted the following experiment. Specifically, the pulse period was set to a commonly used frequency (2-3 kHz), and the laser oscillator was stopped in 10 ms increments, then restarted. The output change was measured with a power meter, and the beam pattern was measured with an infrared camera to confirm the changes in the obtained beam pattern and beam diameter. The experiment showed that the output was roughly constant regardless of the stop time. However, assuming the beam diameter after restarting oscillation was 1, the beam diameter shrank to approximately 0.9 after about 20 ms and stabilized. Since normal machining is performed using a beam whose diameter does not change after about 20 ms, the output of the beam after restarting oscillation would be 1 / (1 / (0.9 × 0.9)), which is reduced to 81%, after about 20 ms. Therefore, the diameter of the machined concave hole is smaller than the target diameter.

[0018] Furthermore, the reason for the aforementioned beam diameter variation is as follows: When the excitation of the laser medium stops, the temperature of the laser medium between the electrodes inside the laser oscillator 1 decreases, leading to an increase in refractive index. Therefore, if the excitation of the laser medium resumes, the refractive index decreases as the laser medium heats up, thus reducing the beam diameter. Consequently, once the temperature of the laser medium stabilizes, the beam diameter will also stabilize in this reduced state.

[0019] See Figure 5 and Figure 7 , Figure 7This diagram shows the beam pattern after the laser oscillation restarts. In the diagram, Dr is the beam diameter of beam Br immediately after the laser oscillation restarts, and Ds is the beam diameter of beam Bs 20ms after the oscillation starts, with Dr > Ds. Furthermore, wr is the output intensity of beam Br, ws is the output intensity of beam Bs, and ws > wr. Additionally, when beams Bs and Br pass through aperture 8, their beam diameters both change to the diameter Da of aperture 8, and are focused by fθ lens 9 onto the surface K (i.e., the imaging position) of the workpiece (printed substrate 10) to form a diameter dw. Furthermore, Dw in the diagram represents the diameter of beam 5 incident on fθ lens 9 (i.e., emitted from fθ lens 9), WS is the output intensity of beam Bs, and the diameter of beam Bs at the processing threshold g on surface K (the completed aperture diameter) is DS. WR is the output intensity of beam Br, and the diameter of beam Br at the processing threshold g on surface K (the completed aperture diameter) is DR. As shown in the diagram, DS > DR, and the aperture stabilizes at DS after 20 ms following the restart of laser oscillation. Furthermore, as mentioned above, the ratio of output intensity WS to output intensity WR is (Ds / Dr). 2 The results above show that by maintaining the temperature of the laser medium within a predetermined range during the processing, the diameter DS of the processed concave hole can be made uniform. Furthermore, in order to maintain the temperature of the laser medium within the predetermined range during the processing, stable laser oscillation must be maintained.

[0020] Based on the above description, the laser processing method for printed circuit boards of the present invention uses a laser oscillator controlled by a high-frequency pulse RF to irradiate a workpiece with a light beam for processing, and includes repeatedly activating the high-frequency pulse RF for a predetermined period of time from the start to the end of processing if the high-frequency pulse RF is not activated within a predetermined time, and directing the output light beam into a damper for absorbing the energy of the light beam.

[0021] In some embodiments, the laser processing machine for printed circuit boards according to the present invention includes a laser oscillator and an optical axis positioning device. The laser oscillator is controlled by a high-frequency pulse (RF) output. The optical axis positioning device consists of a galvanometer device and an fθ lens. The galvanometer device is composed of two galvanometer mirrors, and is capable of positioning the optical axis of the beam output from the laser oscillator to the desired position on the workpiece. A damper is provided between the fθ lens and the workpiece, and the damper is used to absorb the energy of the output beam.

[0022] In some embodiments, the laser processing machine for printed circuit boards of the present invention includes a damper having a window that aligns with the outer edge of the processing area of ​​the workpiece, the window ensuring that the path of the light beam entering the processing area is unobstructed.

[0023] The beneficial effects of this invention are that it can make full use of the capabilities of the laser oscillator and improve processing quality and efficiency. Attached Figure Description

[0024] Figure 1 This is a cross-sectional schematic diagram of the area near the processing section of the laser processing machine of the present invention;

[0025] Figure 2 This is a planar schematic diagram of a damping device according to the present invention;

[0026] Figure 3 This is a flowchart illustrating the control steps of the present invention;

[0027] Figure 4 This is a schematic diagram illustrating an irradiation position point when the present invention is irradiated with a stabilizing pulse;

[0028] Figure 5 This is a structural diagram of an existing laser processing machine;

[0029] Figure 6 This is a diagram illustrating... Figure 5 The sequence in which a laser processing machine processes multiple processing areas of a printed circuit board; and

[0030] Figure 7 It is a schematic diagram illustrating the beam pattern after the laser oscillation restarts. Detailed Implementation

[0031] Before the invention is described in detail, it should be noted that similar elements are represented by the same numbers in the following description.

[0032] Types of invention implementation:

[0033] refer to Figure 1 , 5 -7, the laser processing machine for the printed circuit board of the present invention comprises:

[0034] Laser oscillator 1, whose output is controlled by a high-frequency pulse RF; and

[0035] The optical axis positioning device consists of a galvanometer device 7 and an fθ lens 9. The galvanometer device 7 is composed of two galvanometer reflectors 7a and 7b, which can position the optical axis of the beam output from the laser oscillator 1 to the desired position of the workpiece. A damper 50 is provided between the fθ lens 9 and the workpiece, and the damper 50 is used to absorb the energy of the output beam.

[0036] Figure 1This is a cross-sectional schematic diagram showing the area near the processing section of a laser processing machine for the printed circuit board of the present invention. Of the plurality of galvanometer mirrors serving as the galvanometer device 7, only the galvanometer mirror 7a used to position a beam 5 in one direction X is shown. Furthermore, since... Figure 1 Other structures can be similar to Figure 5 The construction shown, therefore for with Figure 5 For items that are identical or similar to each other or have the same function, the same symbol shall be assigned and repeated descriptions shall be omitted (for relevant descriptions, please refer to the background art described in this specification).

[0037] The laser processing machine includes a box-shaped shield 40. A square recess 40HU is formed on an upper plate 40U of the shield 40, and a square recess 40HD is formed on a lower plate 40D of the shield 40. The dimensions of the recesses 40HU and 40HD do not interfere with the beam 5 passing through them. A recess 40HS on one side 40S of the shield 40 is connected to an attraction device (not shown in the figure). A copper damper 50 is fixed to the lower plate 40D and connected to a cooling device (not shown in the figure). The damper 50 has a thickness of 2mm, and its upper surface 50U is positioned at a height H from the surface K of a workpiece (a printed circuit board 10) during processing.

[0038] See Figure 1 and Figure 2 The galvanometer reflector 7a rotates at an angle of 2θw during processing, with a single-sided rotation angle of θw relative to the vertical line. The beam 5 is directed towards the galvanometer reflector 7a, and the distance between the two ends of the galvanometer reflector 7a's rotation in the direction X corresponds to the length L of the processing area 11 in the direction X. Furthermore, when the beam 5 is incident on the damper 50 to stabilize the output, the galvanometer reflector 7a rotates at an angle of 2θt, with a single-sided rotation angle of θt relative to the vertical line. At the left end of the galvanometer reflector 7a's rotation (corresponding to...) Figure 2 (Left side), the beam 5 is incident on a waiting line Lxl extending in one direction Y, while at the right end of the rotation of the galvanometer reflector 7a (corresponding to) Figure 2 (On the right side), the beam 5 is incident on a waiting line Lxr extending along the direction Y. The distance between the waiting line Lxl and the waiting line Lxr is Lt. Figure 1 The light beam 5, shown with a dotted line, is the light beam incident on the boundary line of the processing area 11. Figure 1 The beam 5 shown in dashed lines is the beam incident on the waiting line Lxl or the waiting line Lxr. Figure 1 In this context, Dw represents the diameter of the light beam 5 incident on the fθ lens 9 (i.e., emitted from the fθ lens 9) (hereinafter referred to as the beam diameter), and dwn is the diameter of the light beam 5 at a height H above the surface K (i.e., the diameter of the light beam 5 entering the damper 50). Here, since the distance between the fθ lens 9 and the surface K of the workpiece (the printed circuit board 10) during processing can be substantially considered as the focal distance f, dwn = Dw × (H / f). That is, for example, when the focal distance f of the fθ lens 9 is 90 mm, the processing height H is 20 mm, and the beam diameter Dw is 30 mm, the beam diameter dwn is approximately 7 mm.

[0039] Figure 2 This is a planar schematic diagram of the damping 50 of the present invention. The damping 50 is square, with a window 50W formed in its center. The window 50W aligns with the outer edge of the processing area of ​​the workpiece, ensuring that the path of the light beam entering the processing area is unobstructed. The width of the window 50W in both the X and Y directions is W, and the width W is α (α > 0) longer on one side than the width L of the processing area 11 plus a beam diameter dwnm. Here, the beam diameter dwnm is the diameter of the light beam 5 passing through the aperture 8 with the largest diameter on the damping 50. The distance between the waiting line Lxl and the waiting line Lxr and the window 50W is (dwnm / 2 + β), where β > 0, and the outer width LA of the damping 50 is longer than (Lt + dwnm). See also Figure 1 , Figure 2 and Figure 5 Although not shown in the figure, the galvanometer reflector 7b, which positions the beam 5 in the Y direction, and... Figure 1 The galvanometer reflector 7a shown is identical to the one shown, and its rotation angle during processing is 2θw. When the beam 5 is incident on the damper 50 to stabilize the output, the galvanometer reflector 7b rotates by an angle θt relative to the vertical line on one side. At the left end of the rotation of the galvanometer reflector 7b (corresponding to...) Figure 2 (Above), the beam 5 is incident on a waiting line Lyu extending along the direction X (shown as a dashed line), at the right end of the rotation of the galvanometer reflector 7b (corresponding to) Figure 2(Lower side), the beam 5 is incident on a waiting line Lyd extending along the direction X (shown as a dashed line). The distance between the waiting line Lyu and the waiting line Lyd is Lt. The four corners of the window 50W are connected by arcs with a radius of (dwnm / 2+α). Therefore, the beam 5 illuminating the damper 50 will not go outside the range of the damper 50. Furthermore, as described above, the lengths of the waiting lines Lxl, Lxr, Lyu, and Lyd are all L.

[0040] The laser processing method for the printed circuit board of the present invention uses a laser oscillator 1 controlled by a high-frequency pulse RF to irradiate the workpiece with the light beam 5 for processing. If the high-frequency pulse RF is not activated within a predetermined time from the start to the end of processing, the high-frequency pulse RF is repeatedly activated for a predetermined period, and the output light beam 5 is directed into the damper 50 for absorbing the energy of the light beam 5.

[0041] The predetermined time refers to "the time during which the output power of the laser oscillator 1 will not decrease." As described earlier in this specification, if the laser oscillation interval is less than 20ms, the output of the laser oscillator will not decrease. Therefore, it can be set to within 20ms.

[0042] The phrase "repeatedly activating the high-frequency pulse RF for a predetermined period" means "repeatedly generating a pulsed laser of a certain power." Specifically, for example, the laser used for copper layer processing in the initial processing area 11 is repeatedly generated every 20 ms. In this case, the repetition time is within the "laser output stabilization period at startup" (see...). Figure 3 The duration is 5 seconds. If it is during the "laser output stabilization period when the XY stage 12 moves" (see...), it is 5 seconds. Figure 3 The predetermined period is the time from the start of the XY stage 12's movement to the completion of the positioning. Here, the predetermined period refers to the pulse width, for example, 15 μs.

[0043] The phrase "injecting the output beam 5 into the damper 50 for absorbing the energy of the beam 5" means "injecting the stabilizing pulse into the damper 50". This corresponds to " Figure 3 As shown in S30~S70 and S90~S130, "Irradiation stabilization pulse" means that the entire stabilization pulse is injected into the damper 50.

[0044] Figure 3 This is a flowchart illustrating the control steps of the laser processing method for the printed circuit board of the present invention. (See also...) Figure 1 , Figure 3 , Figure 4 and Figure 5At the start of processing, the laser oscillator 1 is activated and the control programming is performed (step S10), and the processing step number i is set to i = 1 (step S20). Here, the processing step number i is the sequence number of the processing order of each processing area 11. Next, using the galvanometer reflector 7a and the galvanometer reflector 7b, the axis of the beam 5 is positioned at point Pi (Px, Py) on the waiting line (e.g., the waiting line Lyu) of the damping 50 (step S30) (here, "indicating Pi coordinates" refers to the position of point P1 (Px, Py) indicating the waiting position of the processing area 11 of the processing step number 1). After the positioning is completed (step S40), (here, it is confirmed whether the irradiation position of the beam 5 is positioned at P1 (Px, Py). If the positioning is not completed, it is unknown where the beam 5 will irradiate. If the irradiation position of the beam 5 is on the printed circuit board 10, it will cause damage to the printed circuit board 10; if it is not on the printed circuit board 10, it will cause damage to the laser processing machine), a stabilization pulse of predetermined output and frequency is irradiated (step S50) (at this time, the stabilization pulse is completely injected into the damping 50). Thus, the irradiation time is accumulated each time a stabilization pulse is irradiated, and the irradiation of the stabilization pulse ends when the accumulated time reaches 5 seconds (step S60) (step S70). Among them, the above steps S30 to S70 are the laser output stabilization period at startup.

[0045] Next, the XY stage 12 is moved to position the processing area 11 of processing step i at the processing position (step S80), and the axis of the beam 5 is positioned on the waiting line at point Pi(Px,Py) using the galvanometer reflector 7a and the galvanometer reflector 7b (step S90). (Here, "indicating Pi coordinates" refers to the position of point Pi(Px,Py) of the waiting position of the processing area 11 of processing step i. Typically, the processing start point varies with the processing area 11, and the waiting position on a printed circuit board 10 is almost never the same.) After positioning is completed (step S100), (here, it is confirmed whether the irradiation position of the beam 5 is positioned at the waiting position Pi(Px,Py) of the processing area 11 of processing step i. If positioning is not completed, it is unknown where the beam 5 will irradiate, which will eventually cause damage to the product), a stabilization pulse with a predetermined output and frequency is irradiated (step S110). Furthermore, with each stabilization pulse, it is confirmed whether the processing area 11 of processing step i is positioned at the designated location (i.e., the position opposite to the fθ lens 9) (step S120) (here, it is confirmed whether the XY stage 12 is positioned at the processing area 11 of processing step i). If the processing area 11 of processing step i is positioned at the designated location (i.e., the position opposite to the fθ lens 9), the stabilization pulse is stopped (step S130). Hereinafter, steps S90 to S130 will be referred to as the laser output stabilization period during the movement of the XY stage 12. Thus, after the processing area 11 of processing step i is positioned at the designated location, concave hole processing is performed within the processing area 11 of processing step i in the same manner as in the conventional process (step S140). Furthermore, the initial step in step S140 is to use the galvanometer reflector 7a and galvanometer reflector 7b to position the axis of the beam 5 at the initial concave hole location within the processing area 11 of processing step number i. After the concave hole processing within the processing area 11 of processing step number i is completed (step S150), processing step number i is set to i = i + 1 (step S160), and processing step number i is compared with the maximum value of processing step number j (step S170). If i ≦ j, then the process in step S80 is performed; otherwise, the process ends. Here, the stabilization pulse can be, for example, the processing conditions used when processing the copper layer or insulating layer of the processing area 11. Furthermore, the period of the stabilization pulse can be, for example, set to 20 ms or less (frequency 50 Hz or more). Alternatively, the determination method here can be feedback control (steps S40, S60, S100, S120, S150), or feedforward control can be used to determine the completion signal and the end signal.

[0046] Figure 4 This illustrates the irradiation position of the stabilization pulse in the above flowchart, which is point Pi(Px,Py) (i.e.) Figure 4 The diagram Pi(Qx,Py) shown in the figure indicates that point Ow is the center of the processing area 11. Here, the corners of the processing area 11 are designated C1, C2, C3, and C4. Point Q in the diagram represents the location of the initial concave hole processed in the processing area 11 (i = 1, i.e., the processing start point) for the initial processing operation i. Since point Q is located within triangles C1, Ow, and C4 (including the sides of the triangles, the same applies below), the X-coordinate of point P1 on the waiting line Lyu is set to the same X-coordinate Qx as point Q. This minimizes the distance between point P1 and point Q. Therefore, compared to the case where the irradiation position of the stabilizing pulse is set to a point other than point P1, the above setting shortens the time required for the beam 5 to be positioned from point P1 to point Q. Similarly, when point Q is located in triangles C1, C2, and Ow, the Y-coordinate of point Pi on the waiting line Lxl is set to the same Y-coordinate Qy as point Q; when point Q is located in triangles C2, C3, and Ow, the X-coordinate of point Pi on the waiting line Lyd is set to the same X-coordinate Qx as point Q; when point Q is located in triangles Ow, C3, and C4, the Y-coordinate of point Pi on the waiting line Lxr is set to the same Y-coordinate Qy as point Qi. If point Q is located on a diagonal, for example, on the line connecting C1 and Ow, since the distance from this processing start point to the waiting line Lxl is the same as the distance to the waiting line Lyu, either the waiting line Lxl or the waiting line Lyu can be specified.

[0047] See Figure 3 and Figure 4 Furthermore, although the processing start time of step S140 will be longer, the irradiation position Pi (Px, Py) of the stabilization pulse can of course be set to any point on the waiting line Lyu, the waiting line Lyd, the waiting line Lxl, and the waiting line Lxr. In this case, the irradiation position Pi of the stabilization pulse is preferably set near the location where the damper 50 connects to the cooling device (omitted in the figure). The damper 50 can be circular or square, and its diameter can be larger than the beam diameter dwnm of the beam 5 passing through the aperture 8 with the largest diameter. Furthermore, the output per unit area of ​​the stabilization pulse incident on the damper 50 is approximately 0.02% of the output when a 100μm recess is formed in the copper layer of the printed circuit board 10.

[0048] The laser processing machine and laser processing method for printed circuit boards of the present invention can be applied to existing laser processing machines for printed circuit boards. For example, in the case of a laser processing machine where the processing area 11 is 50×50mm, setting the damping 50 of the present invention will substantially reduce the processing area 11 of the laser processing machine to 30×30mm. In this way, if the same size printed circuit board 10 is processed, the number of movements of the XY stage 12 will increase. However, if the processing area 11 is 30×30mm, the laser processing method for printed circuit boards of the present invention can be easily adopted simply by setting the damping 50 in the laser processing machine for printed circuit boards of the present invention.

[0049] Furthermore, the damping device 50 of the present invention is not limited to carbon dioxide laser processing machines, but can also be applied to other laser processing machines.

[0050] The above description is merely an embodiment of the present invention and should not be construed as limiting the scope of the present invention. Any simple equivalent changes and modifications made in accordance with the claims and description of the present invention shall still fall within the scope of the present invention.

Claims

1. A laser processing method for printed circuit boards, comprising irradiating a workpiece with a laser beam controlled by a high-frequency pulse RF to perform processing, characterized in that: The device includes a laser oscillator with an output beam, an optical axis positioning device consisting of a galvanometer and an fθ lens that positions the optical axis of the beam to a desired position on the workpiece, and a shield disposed between the optical axis positioning device and the workpiece and connected to the suction device. and If the high-frequency pulse RF is not activated within a predetermined time from the start to the end of the processing, the high-frequency pulse RF is repeatedly activated for a predetermined period, and the output beam is directed into a damper set on the shield to absorb the energy of the beam. The predetermined time refers to the time during which the output power of the laser oscillator is not reduced.

2. A laser processing machine for printed circuit boards, comprising: Laser oscillator, with output controlled by high-frequency pulse RF; and The optical axis positioning device consists of a galvanometer device and an fθ lens. The galvanometer device is composed of two galvanometer mirrors and can position the optical axis of the beam output from the laser oscillator to the desired position of the workpiece. Its features are: The laser processing machine also includes a shield disposed between the optical axis positioning device and the workpiece and connected to the suction device; The shield is equipped with damping, which is used to absorb the energy of the output light beam; and If the high-frequency pulse RF is not activated within a predetermined time from the start to the end of the laser processing, the high-frequency pulse RF is repeatedly activated for a predetermined period, and the output beam is directed into the damper set on the shield to absorb the energy of the beam. The predetermined time refers to the time during which the output power of the laser oscillator is not reduced.

3. A control method for a laser processing machine for printed circuit boards, comprising using a laser oscillator controlled by a high-frequency pulse RF to irradiate a workpiece with a laser beam for processing, characterized in that: The device includes a laser oscillator with an output beam, an optical axis positioning device consisting of a galvanometer and an fθ lens that positions the optical axis of the beam to a desired position on the workpiece, and a shield disposed between the optical axis positioning device and the workpiece and connected to the suction device. and If the high-frequency pulse RF is not activated within a predetermined time from the start to the end of the processing, the high-frequency pulse RF is repeatedly activated for a predetermined period, and the output beam is directed into a damper set on the shield to absorb the energy of the beam. The predetermined time refers to the time during which the output power of the laser oscillator is not reduced.

4. Damping in a laser processing machine for printed circuit boards, the laser processing machine comprising: The laser oscillator is controlled by a high-frequency pulse RF output; The optical axis positioning device comprises a galvanometer device and an fθ lens. The galvanometer device consists of two galvanometer mirrors and is capable of positioning the optical axis of the laser beam output from the laser oscillator to the desired position on the workpiece. A shield is positioned between the optical axis positioning device and the workpiece and connected to the suction device; Its features are: The damper is disposed on the shield, and the damper is used to absorb the energy of the output light beam; and If the high-frequency pulse RF is not activated within a predetermined time from the start to the end of the laser processing, the high-frequency pulse RF is repeatedly activated for a predetermined period, and the output beam is directed into the damper set on the shield to absorb the energy of the beam. The predetermined time refers to the time during which the output power of the laser oscillator is not reduced.

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