TWI221791B - Laser processing system and laser processing method - Google Patents

Abstract

A laser processing system is proposed. It is characterized in having a pulse laser oscillator (2) and an optical system (3). The pulse laser oscillator (2) changes the input discharging power supplied between the electrodes (24) by switching the discharge command pulse constituted of a given frequency to render the characteristics of laser beam (6) variable. The optical system (3) is adapted to lead the laser beam (6) produced from the laser oscillator (2) to the work to be processed.

Description

1221791 V. Description of the invention (1) [Technical field to which the invention belongs] The present invention relates to a laser processing system for making through holes, blind holes, etc. of a processed object, groove processing, shape cutting, and the like. The laser processing method is particularly related to a laser processing system and a laser processing method for improving processing quality and productivity. [Prior Art] A printed wiring board is composed of a plurality of insulating substrates' with a conductive layer disposed thereon, and the layers are laminated. In addition, the conductor layers provided on the respective insulating substrates are electrically connected between any of the conductor layers in the vertical direction through via holes called via holes and blind holes. Fig. 14 is a sectional view for explaining the above-mentioned conventional multilayer printed wiring board. In the figure, 1 is a printed wiring board, 1 1 a, 1 1 b are insulating substrates, 12 a to c are conductor layers, and 1 3 Is a metal plating layer, 1 4 a is a through hole between the conductor layer 1 2 a and the conductor layer 1 2 b through the insulating substrate 1 1 a, and 1 4 b is a conductor that penetrates the insulating substrate 1 1 a A via hole between the layer 12a and the conductive layer 12c laminated and bonded by the insulating substrate 1b. In addition, the via hole 14a is generally referred to as a blind hole (B 1 ind V a Ho 1 e); and the via hole 14b is referred to as a through hole (Through Hole has a bottom hole). As shown in FIG. 14, the printed wiring board having via holes i 4 a and i 4 b is provided with a high-performance electronic device, and it must be provided with multiple layers and miniaturization (high density) of the printed wiring board. In order to meet the above requirements, a method for processing the through holes 14a and 14b shown in FIG. 4 by using a laser beam is proposed, and has made progress.

314581.ptd $ 6 pages 1221791 ---- ^ V. Description of the invention (2) Brother 1 5 The picture is' used to explain the blind a $, ι π μ, a field beam on the printed wiring board t «For optical control == printed wiring board, 2 for laser oscillator, 3 for each machine connected to the table, 2 = 2 for beam center

When V-beam is irradiated: It is field: The peak power of A-beam 'η is the pulse width (light, τ1 is the time when the beam is irradiated. The actual processing operation will be described below. Μ Optical system 3 is used for laser oscillator The laser beam b of the output laser beam 2 is shaped, and is ,,,, and ^. The printed wiring substrate irradiating the processing object from I and the court is reversed to JL. 〇 At Kori-ji Temple, Lei " M jik soil "Beam" is a pulse laser irradiation energy with the symbol 9 shown in Fig. 15 for example, M > π ^ ^ Α The laser pulse is irradiated to each hole several times (shot). The laser after irradiation Dope 70 came to 'remove the printed wiring board 1 by thermal dissolution to form holes in the printed wiring board. Figure 16 is a stand-up picture of the printed wiring board formed by the above-mentioned processing method. An example of a cross-sectional view. In Figure 16 Φ ..., r, τ '1 5 a is the upper hole diameter, 15 b is the middle hole diameter, 1 5 c is the lower hole diameter, and 16 is the hole diameter. Depth, 17 is the damage of the processing resin residue ^ ^ ', ", and the copper foil on the inner surface, the other is the same as in Figure 14 The same parts are marked with the same question + ^ & the explanation of the door is omitted, and its explanation is omitted. Lance lj 田 _ When carrying a beam of light for processing, in order to ensure the quality of the processing, the general focus is on the focus. The processing aperture of Figure 6 is 15a to 15c.

314581.ptd Page 7 1221791 V. Description of the invention (3) ~~ ---- Depth of work 1 6, Poor machining 1 7, 18, etc. Therefore, it must be equal to the beam energy (peak power x pulse width), And ,: make the beam directly according to time, and especially the beam energy will be damaged or distorted due to the material ^ beam irradiation, and affect the generation of plasma, etc .; the composition of the bucket causes parameters. 5 Ai is a very important control. Generally speaking, the energy of the first irradiation beam irradiated to the hole hitting each hole is set to E i, and the laser vibration soup 2 ° is set to E t, and the power is set. Is Pi, which is controlled by the optical system: the transmission rate of the medium-peak peak power at the exit is set to α i (hereinafter, thick =

) 'The beam pulse width is set to wi, irradiated to each-η ~ beam transmission rate-η. ^ When the number of holes is Zhao · M 〇 and 疋 is S, as shown in Equation 1,…, shooting mode 1 ^ pLixPi) xWi \ W i, the control can control the beam transmission rate Q: i, the peak power Pi controls the beam energy E t. Here, on the traditional laser processing system, in the optical system 3, the loss of knowledge and light changes caused by the loss caused by the absorption of the first beam transmission rate when forming the beam pattern, i. The method of transmitting the light beam transmittance α 丨 is shown in FIG. 1, and G s. For example, a method in which the cover 31 and the collimating lens 32 shown in FIG. 17 are circled to the optical system 3. The objective lens (object) is attached to Figure 17 and propagates with a beam diameter D 丨 3 2 into the jujube, Zhitu said] Nine series through the collimating lens Λ and then use the mask 31 to shape the beam mode ( Huga

Description of the invention (4) The working point is necessary to make the input light at this time = 2). The difference between the volume of the beam pattern and the output beam pattern is the loss caused by the entry loss. The "knowledge" is determined based on the mask 31 U and the mask diameter D and the focal length f 'of the collimator lens 32, D, and D. As long as the distance L of the collimating lens 3 2 is determined, for example: the name is lost — almost no action, D is large, and the focal length f is approximately equal to the distance L. The volume is almost ^ # " The volume of the pattern is close to that of the input beam mode 且, and the φ / she and the opposite are different and the transmission rate ai of the nine beams becomes larger. In the case of death, it is smaller, the focal length f is longer, and the distance L is shorter. The light-in-light loss mode volume of the wheel-out beam mode is significantly smaller than the beam mode volume, and the beam transmission rate α 丨 also becomes smaller. Among the three parameters of straight through im f and ratio, since the mask D is determined by the necessary beam diameter at the processing point, that is, the processing aperture, ^: ϊ T @ S, and the distance L can be moved through the machine, because , J private movement distance L changes the beam transmission rate α i. Since the distance L is changed by a servo motor, it takes more than 100ms to change it. In addition, the peak power Pl is fixed, or even if it can be changed, it is only about ± 20% of the rated value. In addition, it must take more than 100ms to make the change. The following description uses the schematic diagram of the carbon dioxide laser oscillator shown in FIG. In the figure, 21 is the laser frame, 22 is the mixed gas with the laser medium C02, 23 is the AC power source, 24 is the electrode, and 25 is the excitation and discharge.

314581.ptd Page 9 1221791 V. Description of the invention (5) --- Electricity, 26 is a partial reflection mirror, 27 is a total reflection mirror, 28 is an aperture defining a laser oscillation mode, and 29 is a laser The beam light 6 is an output laser beam. In the carbon dioxide laser oscillator having the composition shown in FIG. 18, the voltage of the AC power source 23 is applied between the electrodes 24 to form an initiating discharge 25, and the C 0 2 gas is excited at an upper level. The density of particles excited by the discharge at this time is referred to as the discharge power tolerance. In the resonator consisting of the mirror 26 and the total reflection mirror 27, the laser beam is amplified by the stimulated C02 gas stimulated emission, and the laser beam is centered on the optical axis 29 of the laser beam. The output laser light is here. Generally, when a gas laser using a carbon dioxide laser is used, the loss of the common oscillator is maintained constant, and the peak value of the laser beam is approximately proportional to the discharge power density. The discharge power density is proportional to the discharge power from the AC power source 23 to the electrode 24. 々 ’large Therefore, the conventional laser oscillator promotes changes in the discharge power density by controlling the way it is applied between the electrodes. When the voltage is too high, the power supply will generate an excessive load, and the fault and the electrode will be damaged.夂 Power supply In addition, when the voltage drops too low, it will not be able to discharge and cause a state where the beam cannot be used. # μ 出 LAS Therefore, in general, the range of the changing voltage is limited to about 20% of the rated value; at the same time, the peak power of the laser beam can only be changed by ± ~ 20%

314581.ptd Page 10 1221791 V. Description of the invention (6) The right 0 rate of the fan is stable, the laser is excited, the laser is excited, the discharge is triggered, and the time of the surge valve is slow. For each pulse (below the pulse laser), the peak energy range of the instantaneous beam energy is shot. Pulse time is delayed by the time of electric discharge. Due to the discharge value, no laser oscillation is caused. In order to ensure that the voltage is more than 100ms, the maximum oscillation frequency of the oscillator cannot be used. In addition, the laser wheel is pulse width), and the discharge width is subtracted from I. The reason is : Start excitement X time) low 柃 laser compared to the phenomenon of initiation of discharge initiation. (Of course, the composition varies, etc.) Width W i (the following width is approximately the same (the width is approximately the same below.) The energy (discharge power density is used for laser output, so the time will show a backward structure and gas

In addition, by controlling the discharge width, specifically the time width of the second power, the laser pulse width can be adjusted at will, which means that (in the range below the maximum oscillation frequency of the pulse laser oscillator) the switching control is pushed parameter. ㈤) Suitable 仃 However, there is an upper limit on the pulse width because the input power is limited depending on the power supply load.

As described above, in the conventional laser processing system, it is difficult to change the peak power due to the beam energy. Therefore, it is controlled by the optical system beam transmission rate ai and the beam pulse width Wi. At this time, the beam pulse width wi is the only control parameter. Next, the type of laser irradiation will be described.

314581.ptd Page 11 1221791 V. Description of the invention (7) 'Laser irradiation types can be roughly divided into two types: burst (bur st) processing, that is, as shown in Figure 19, determined at the position of the opening After the beam is irradiated, only the laser pulse is continuously irradiated to reach the number of irradiations s necessary to form the hole; and the cycle processing 'that is, as shown in FIG. 20, the number of openings is set to η, and the openings are formed. When the required irradiation number is set to s, the beam irradiation position is determined at the position of the hole, and the operation of irradiating the laser pulse once for s times is repeated. Taking the pressing process as an example, the laser oscillation time required for the kth irradiation to the (k + 1) th irradiation in each hole is set to Tok (equivalent to the resting time of beam irradiation in burst processing), and the sth When the pulse width of each irradiation is set to Ws' and the positioning time from the (1st) hole to the jth hole is set to Tg j, the processing time required for the η openings can be expressed by the following formula: Ws < < Σ Tok, which leads to: ^ ... the formula of Equation 3.

When the average value of Tg j is set to Tg, the average value of Tok is set to τ〇, and the average value of Tb is Tba: Therefore, the processing time is determined by the laser oscillation time To and the number of irradiations s.

314581.ptd Page 12 1221791 V. Description of the invention (8) and positioning time T g are determined. On the other hand, in the cycle processing, if the pulse width of the i-th irradiation of each hole is set to Wi, and the positioning time from the (j-1) th hole to the j-th hole is set to Tg ij, then The processing time Tc required for the n opening operations can be expressed by the following formula:

Tdxjm... Formula 5 / * 1 jZi In general, Wi < < T g i j leads to: rc ^ Σ Σ Tgij · · Formula 6 i = 1 j-1 formula. When the average value of Tgi j is set to Tg,

The average value Tea of Tc can be expressed by the following formula:

Tea = nx sxTg • • Equation 7 Therefore, in cycle processing, the processing time is determined by the number of irradiations s and the positioning time Tg. The difference between cycle processing and burst processing will be described here. Cyclic processing can prolong the dwell time T q c of the beam irradiation of each hole. Therefore, the periphery of the processing hole is less affected by heat, and the processing quality can be improved. In contrast, during the burst processing, each hole is performed during the laser oscillation time To

314581.ptd Page 13 1221791 V. Description of the Invention (9)-Machining ’Therefore, the resting time Tqb of the beam irradiation is shorter than Tqc (), and the surrounding area of the machining hole is prone to heat. In addition, regarding the processing time, according to formula 4 and formula 7, under the condition of general and ancient Tg > To, because " Tca-Tba = nx (sl) x (Tg-T4 > 0.) · Formula 8 > Tab is considered in Therefore, compared with cyclic processing, the processing time productivity is also better when using burst processing. As mentioned above, the traditional laser processing system uses a photomask to make the beam diameter, and the discharge power density and discharge width. The optical system is used to control the beam energy, and the processing quality and productivity are ensured by burst processing and cycle selection, and by controlling the beam stop time according to the laser oscillation frequency during the burst processing. In addition, Japanese Patent Laid-Open No. 4-4 i 〇 The 9th Tiger Gazette discloses laser processing of 5 materials. The laser processing is to perform a laser output with a second peak power, to process one of the foils 1 and 4 of the printed wiring board 1, and to apply f-edge resin. 5 Processed to the inner copper foil i 6. Generally, e 'because the processing of steel foil is not easy, it is necessary to increase the beam energy. On the other hand, because the copper foil slant peak power of the laser beam slurry absorbs the laser energy. Reflectivity Therefore, it is easy to generate plasma for a long time, and it also has characteristics. Copper foil has a large thermal conductivity, which can be quickly heated and quickly compared to the direct control and irradiation. Copper irradiates the electrical cooling

314581.ptd Page 14

1221791 V. Description of the invention (10) Therefore, it is generally believed that in order to penetrate the copper foil, a method of irradiating a large amount of beam energy in a short time can be used, that is, a laser beam with high peak power and short pulse width (in The method of S 1) in Fig. 21 is more suitable. In addition, compared with the above-mentioned copper foil, the insulating resin is easier to process and can be processed with only a small amount of energy. However, in general, because the thickness of the insulating resin used for printed substrates is thicker than that of copper foil, the overall resin is processed The total energy required must be increased accordingly. However, like the aforementioned copper foil, when a large amount of beam energy is irradiated in a short period of time (increasing the peak power), the insulating resin with a small thermal conductivity cannot transmit the thermal energy in the depth direction, and the thermal energy is diffused in the horizontal direction. As a result, not only the desired processing depth cannot be obtained, but also the phenomenon of resin residue 17 or internal expansion 19 as shown in FIG. 24 may occur. Therefore, in order to penetrate the insulating resin, it is generally considered that a method of irradiating a laser beam with a low peak power multiple times (S2 to S6 in FIG. 21) is more suitable. As described above, it is generally considered that by selecting various conditions of the laser pulses to be irradiated, it is possible to carry out the penetration processing of the surface copper foil 12a and the copper foil that reaches the inner surface of the insulating resin 11 without destroying the processing quality. 1 2b penetrating processing. However, in actual processing, when the existing laser processing system is to be used, it is usually subject to the following restrictions. First, in the conventional laser processing system, as described above, there is a lack of a method for greatly changing the peak power, and in particular, it cannot be changed instantaneously (in a range below the maximum oscillation frequency of the laser oscillator).

314581.ptd Page 15 1221791 V. Description of the invention (11) Second, in the traditional pulsed laser oscillator, due to factors such as power supply capacity, the oscillator that outputs a laser beam with high peak power cannot output a longer pulse width. Laser beam, on the other hand, a laser beam with a longer pulse width cannot output a laser beam with high peak power. Therefore, in the traditional laser processing system, since the laser irradiation patterns shown in Figure 22 and Figure 23 are used for processing, it is not easy to balance processing quality and productivity at the same time, and one party must be sacrificed. Figure 22 shows the laser when using the traditional laser oscillator that uses the laser oscillator 2 of Figure 15 to output a high peak power and short pulse width (1 to 15 // s). Irradiation pattern and processing state. As in S 1 1 in Fig. 22, a laser beam with a high peak power and a short pulse width is irradiated during the first irradiation to penetrate the surface copper foil 12a ° and the insulating resin 1 1 a is processed. At this time, the peak power is reduced, and the laser beams S 1 2 to S 1 5 are irradiated 4 times. In addition, during the sixth irradiation, in order to remove the residual resin, a laser beam 16 with a slightly increased peak power was irradiated. Through the processing method shown in Figure 22, a certain degree of processing quality can be obtained. However, as described above, in order to significantly reduce the peak power after the second irradiation, the above-mentioned optical system or the like must be used, but the burst processing cannot be performed because it cannot change instantaneously. Therefore, it is necessary to adopt a cycle process that causes a decrease in productivity and a process that increases the number of shots, resulting in a significant reduction in productivity.

314581.ptd Page 16 1221791 V. Description of the invention (12) For example: the number of holes n = 1 0 0 0 0 'the average positioning time of the gate when the conditions need to be switched τπ0.01.1 second (1kHz), the number of irradiation When the processing time is 60 seconds, compared with the case where the processing time is 30 seconds when the burst processing is assumed to be the same number of shots (Tο = 〇 · 〇〇〇〇05 seconds (2kHz)), the productivity is only 1 / 2. Fig. 7… Fig. 23 shows: With a traditional oscillator, Ray 2 'in Fig. 丨 5 uses a low output peak power (which is "" two times below "of the oscillator in Fig. 22) and has a long pulse width (for example 丨6 to i 5 〇) Irradiation type and processing type.) The laser when the field is first beamed is shown in S 2 1 in Figure 2 3. Although the force of the moss is strong and the pulse width of the branch beam increases the beam energy, Measure people and hunt for the long-lasting laser, so according to the above reasons, if the power is not greater than, the power is below 丨 ", the light gram of the energy & den μ ΐ The first time shown in Figure 2 In the case of C ::, it will not be easy to penetrate. When: will lead: the pulse width must be longer than necessary. Interesting. ;: Beam, so that energy cannot be transmitted to ... Beam Πί Β3 surface steel fall must use a high-energy Leibu Bu (in this example, the second time irradiation through the table value t low power and long pulse width The laser pulse is under-irradiated; "I;;:, to the inner surface of the steel box · Using the above method, although the two shots to remove the residual resin. Can be processed through the surface steel foil 1 2a and insulation trees

Page 17 1221791 V. Description of the invention (13) Grease 1 1 a, but because too much energy is applied to the copper foil, compared with the example shown in Figure 22, its processing quality is more likely to deteriorate. In addition, as described with reference to Fig. 22, since the peak power cannot be changed instantaneously, only cycle processing can be performed and burst processing cannot be performed. As mentioned above, when processing a multi-layer printed wiring board made of materials with completely different materials, it is difficult to take into account both the processing quality and the increase in yield if a conventional laser processing system is used. In addition, because there are many types of printed wiring boards, and each processing content varies depending on resin processing, copper foil, resin grease mixed processing, etc., it is difficult to perform all processing with a single laser processing system, and at the same time, It must also consume huge investment equipment. [Summary of the Invention] The object of the present invention is to solve the above-mentioned problems, and provide a laser processing system that can not only reduce the yield but improve the processing quality for printed wiring boards of various materials, and laser processing using the device. method. In order to achieve the above object, according to a first aspect, the present invention includes a pulse laser oscillator that changes a discharge power input between electrodes by changing a discharge command pulse composed of a predetermined frequency to change a laser beam characteristic; The laser beam output by the laser oscillator is guided to an optical system of a workpiece. In addition, the optical system is provided with a switching device to switch the laser beam output from the laser oscillator to a filter member that can pass through and can change the peak power of the laser beam, And beam

314581.ptd Page 18 1221791 V. Description of the invention (14) Appropriate path of filter members with different transmittances. # 2: i is equipped with: a laser oscillator that generates a spark discharge between the electrodes and emits the emitted light beam; the electric optical device to guide the laser beam through the oscillating input beam to the processed object, which can pass the laser through the laser The + radiation switching device output by the radiation oscillator is to cry first by changing the value of power to a variable tear that should pass through. ^ The appropriate path of the calender components with different laser beam permeability is described. In addition, by turning on and off the switching device, it is possible to control the path of the filter member in Tongri Temple, and control the pulse width m 矣 to the pulse width to be passed. Shu Zhen Lu Zhi's laser beam is made by: ίί! The laser processing side ☆ belongs to a kind of discharge electricity that is switched by using ☆ 'and using it can make the laser beam special two: between the electrodes is lower than the laser vibration The maximum vibrating plate of the device is used to instantly switch between households in each pulse;-3 conditions such as the peak power of the field shot pulse and the pulse wide shot. When the nine-beam irradiation is stopped, the conductor is removed Layer, the insulation layer is removed by approaching the output of the laser oscillator's maximum 1 pulse ^ w \, and the pulse width of the short pulse width of 1 to 15 / S plus / ^ plus I '. Sundial is processed by the above-mentioned first pulse, the second pulse with a peak power output of W2 to 1/10 and a long pulse width with a pulse width of 16 to 200s. In addition, it is processed by switching discharge Command pulse, laser in one pulse

314581.ptd Page 19 1221791 V. Description of the Invention (15) During the output period Θ, the peak power is set to be variable, and the output laser beam is processed. ... In addition, the Hai pulse is based on a short period of the first area of the laser oscillator with a peak value of 1 to 15 / Z s and a peak power of 16 to 200. // The laser output of the first pulse for a long time is processed. [Embodiment] of the first embodiment Figs. 1 and 2 of the first embodiment are related to the first embodiment. Fig. I is a schematic diagram of the laser processing system of Fig. 1 and Fig. 2 is used for A schematic diagram of a device for controlling a bright laser irradiation form will be described. Only in the first figure, 6a and 8a show the laser beam and laser irradiation form output by the laser oscillator 2A, and 7a and 9a show the laser beam and laser irradiation form after the optical system is used. The other parts that are the same as those in FIG. 15 are marked with the same symbols and their explanations are omitted. In the second figure, 4 1 a and 4 1 b are discharge command pulse groups, 4 2 a and 4 2 bA are discharge power pulse groups, 4 3 a and 4 3 b are discharge energy, 4 4 &, 4 4 output ... Laser beam energy. ~ ® bu fh 丨 1 is the frequency of the parent current power supply, I u and id are the effective discharge power densities, Nu and Nd are the average discharge power densities, Ds,… are the discharge widths, and i is the power value 'Ws, W1 is the pulse width , Ls, li show the delay of laser oscillation. The description of the gas is generally used in the chaos of the carbon dioxide gas laser oscillator. . Alas, when the loss of resonance state is maintained to a certain degree, the system

314581.ptd Page 20 1221791 V. Description of the invention (16) Control the discharge power density and discharge width to change the peak power and pulse width of the laser beam output from the oscillator. Since the discharge power density is proportional to the input power, in the prior art, the discharge power density was changed by changing the voltage applied between the electrodes. This implementation mode is concerned with a laser oscillator focusing on: the input power is divided into the instantaneous power and the average power of the average time, and the peak power of the laser beam is controlled by the average power of the average time After setting the voltage to be constant (setting the effective discharge power density to be constant) and controlling the number of discharge power pulses per unit time to control the average discharge power density, the peak power of the laser beam is changed. . In other words, the three conditions of the peak power, the pulse width, and the resting time of the laser pulse to be irradiated are switched instantaneously at each pulse according to the material, material composition, processing thickness, etc. of the processed portion of the printed wiring board. Here, because the prior art keeps the number of discharge power pulses constant, the effective discharge power density and the average discharge power density form a one-to-one relationship. Therefore, the effective discharge power density is changed according to the voltage change to control the average discharge power density. . The operation will be described below with reference to FIG. 2. First, when a discharge command pulse is applied at a time interval of 1 / f P, a discharge power pulse (frequency f P) is inputted between the electrodes by an AC power source in synchronization therewith. The direction of the discharge power pulse is the instantaneous continuous discharge power density I ′

314581.ptd Page 21 1221791 V. Description of the invention (17) The average time is the average discharge power density N. When the voltage applied between the electrodes is set to a constant value, the effective discharge power density also becomes constant. The more the number of discharge power pulses m per unit time, the higher the average discharge power density and the peak power p of the laser beam. With it. For example, when a discharge command pulse is given at a short time interval (1 / fh), the discharge power pulse (increasing the number of discharge power pulses input per unit time) is synchronized with the high-frequency fh input through the AC power supply, so that The average discharge power density Nu is increased to output a laser beam with a high peak power Pu. In contrast, when the discharge command pulse is applied at a long interval (1 / f 1), the discharge power pulse (the number of discharge power pulses input per unit time becomes smaller) is synchronized with the AC power at a low frequency Π. , So that the average discharge power density Nd becomes low to output a laser beam with a low peak power Pd. In addition, as described above, the pulse width of the laser beam can be changed by changing the time when the electric power is input into the electrode. The power input time width D can be expressed by the following formula: D = (1 / f p) x m Equation 9 Therefore, by controlling the discharge command pulse interval 1 / f p and the discharge power pulse number m, an arbitrary pulse width can be obtained. As described above, in this embodiment, the peak power of the laser beam is controlled by adjusting the frequency of the AC power supply, and the pulse width of the laser beam is controlled by changing the time of inputting power to obtain an arbitrary laser pulse. . Specifically, an arbitrary laser pulse can be obtained by controlling the time interval of the discharge command pulse and the number of discharge command pulses.

314581.ptd Page 22 1221791 V. Description of the invention (18) In addition, according to the present invention, the effect of the pulse width is wider than the pulse width within a certain power supply load range. From setting the peak power at a higher peak power to a shorter peak power at a shorter length, it has the option of expanding the pulse waveform. With the above control, the peak power and pulse width of each laser pulse can be arbitrarily changed, and an arbitrary lightning can be obtained. The radiation irradiation pattern 8 a is formed by using the optical system 3 to obtain the obtained laser irradiation pattern ^ as a laser irradiation pattern 9 a and transferred to the printed wiring board 1 as a processing object for processing. Hereinafter, a burst processing method using the above-mentioned laser processing system will be described. For example, the processing of the same printed circuit board as in Figure 21 is illustrated, that is, it is composed of the first layer of copper foil 1 2 a, the second layer of insulating resin 1 1 a, and the third layer of inner copper foil 1 2 b When the printed circuit board is processed. Fig. 3 is a schematic diagram showing the irradiation form of the laser beam, and Fig. 4 is a schematic diagram showing the processing state at this time. In Fig. 3, S3 1 to S3 3 are laser beams' for each of the first to third irradiations of each hole, and each area indicates the beam energy. In addition, P is the peak power, W is the pulse width, To is the laser oscillation time, and Tg is the positioning time. In Figure 4, 1 2 a is the surface copper junction, Π a is the insulating resin, 1 2 b is the inner copper foil, 20 is the planned processing position, 1 4 a is the blind hole after processing, S 3 1 to S3 3 are laser pulse waveforms of the first to third irradiations, and a1 to a3 are processed portions processed by the laser beams of the first to third irradiations, respectively.

314581.ptd Page 23 V. Description of the invention (19) In this embodiment, the material of the printed wiring board or the laser irradiation pattern not shown in the figure is used, and the processing thickness of the laser beam is instantly switched during the pulse. For each condition of the irradiation dwell time, it is equal to ±, pulse width, and beam to achieve the purpose of shortening the processing time. a Using a burst processing method, using the materials described in the prior art to describe the implementation of this method using Figures 3 and 4 ^ |, the relationship between beams is the premise. First, with the first irradiation of the field, σ 工 方法. For the laser pulse of foil 1 2a, A ^ first beam S3 1 is used to process the first layer of copper through layer 丨: ：:: = = and with a stable * insulation 桝 n laser beam s of human makeup 3 2 is the laser pulse for processing the second sound and also the resin 11 a, which is the condition of the knife layer of the knife knife π and achieves the purpose of improving productivity '(about 0.5 kW), and the pulse width _ Η The rate is low (0 · 0 5 to rush. The laser pulse is long (80 to 2 0 0 / / s). The laser pulse is shown in Figure 21, and the flute is set to 1 Low-peak power below 6 and the "" laser pulse, the laser pulse, so in Figure 21 t, the laser beam of 4 "pulse width of the laser beam" but according to the present: m must irradiate a complex number By increasing the pulse width to spread in the diameter direction, and keeping the processing aperture, the results are immediately maintained, because it can reduce / shoot through the insulating resin. To reduce the number of irradiations while maintaining processing quality,

314581.ptd Page 24 1221791 V. Description of the invention (20) and save the extra light to hit the Japanese soldiers, and then to the Chu, ", shoot off, and improve productivity. According to the three exposures In the 2 laser irradiations, the laser light is not beamed. S33 is used to process the laser pulse in the first punch. Because of the laser + spear, the insulating resin 11 a laser pulse: two: by volume :: guide :: layer Radon damage, so the irradiation power can be higher than the residual resin content of the second shot, the peak power of the peak power of the second shot (0 " k. On; so the irradiation is slightly higher than the second A s level) laser Pulses .. Degree) and shorter pulse widths U to 30. As described above, in this embodiment, by using a laser beam irradiated three times, the printing quality can be described and the number of irradiations can be reduced. " Good processing. To summarize the above description, according to this implementation mode, the material and composition of the board are below the shooting data; " matching :: base is optimized, and the peak of the instantaneous change :: rate of power is the effect of productivity. Raise the processing mouth and shell, for example: the number of holes η = 100, the matching conditions are 1 digit time. = 〇.οοΜ seconds (2kHz), the working time of the photo: 15 seconds, compared with the laser irradiation '3 shots' in Figure 20, shortened by 45 seconds. This kind of method < is used for the hole-cutting processing of printed wiring boards with multiple layers made of high-coat processing materials; the method has different effects. In particular, it can be used for a long time. In addition, although the above description is about the blind hole processing, it is the same.

314581.ptd Page 25, 1221791 V. Description of the invention (21) When applying this method to the processing of through holes, it can be matched with the material or material of the printed wiring board to reduce the oscillation below the pulse laser oscillator. Within the frequency range, the peak power of the laser beam, the pulse width, and the quiescent rest time of the beam are optimized in each pulse, thereby achieving the effect of improving the processing quality and productivity. In addition, although the above description is for the burst processing, of course, although it is also two-cycle processing, compared with the burst processing, the productivity of the cycle processing is low, but it can obtain a more stable and good processing quality. It can also be applied to processing methods that use both burst processing and cyclic processing: Quality removal ::::: Light = Photo: Off time 'with printed wiring board to maximize &# 2 π ^ The peak power and pulse width of the laser pulse The method of deciding the resting time of the beam with varying amplitude is stable and good. It can not only achieve safety, but also achieve the effect of improving productivity. System, available! Taiwan Laser Processing Laser Processing System- Le, and this Lufang also added a variety of printed wiring substrates in the above-mentioned first embodiment, the political density and discharge width, so that the laser will explain the change in the electrical generation by changing the average discharge, ~ Peak power and pulse width output transmission rate of 2 ... In this embodiment, the beam transmission rate of the optical system can be changed. The heart τ system considers the beam transmission of the optical system.

1221791 V. Description of the invention (22) Figure 5, Figure 6, and Figure 7 of the cage, Figure 5 is a diagram explaining the 8th of the night, and is related to the second embodiment. Figure 6 is an illustration and a copy § The model of the laser processing system is the same as that of the younger brother 6Η, which shows the shape and pattern of the laser irradiation control. It is shown as the #zhizhizhi diagram of the control of the laser irradiation shape. Figure 8 is the objective lens; The light beam of one example of the objective lens =: '45a, 45b in the figure are lasers formed by using the optical system. In Figures 7 and 8, 33 is the objective lens of the control device that can change the laser at any time, 34 is The optical high-speed switching element used to appropriately change the path of the incident beam 6b is transmitted. The beam with the laser peak power of the laser 33 of the upper mirror 33 is transmitted to a translucent mirror with a different cultural incidence. 36 is A damper for laser light of each phase. And reflected by the harvesting transparent mirror 35 In addition, for convenience of explanation, the laser light whose path is changed by 37a, 37B switching elements 34a, 34b. . Utilization of child month: ° Child month output from the intrinsically yoke type sad optical system to the peak power and pulse width of the laser beam. First of all, Fig. 6 illustrates the operation of changing the pulse width when the beam transmission rate is changed. τ value knife hand 'Assuming that the beam transmission rate of the optical system is fixed at 100% (it is set to 100% by Ming Λ), the same peak power is transmitted from the laser beam to the laser beam. And the pulse width is transmitted to the processing point. Here, when passing through an objective lens with a constant beam transmittance, the laser vibration

314581.ptd Page 27 1221791 V. Description of the invention (23) f input by J device. Of the laser beam, # A% is absorbed by the object Yin, C% reflects the objective lens (A + B + c = 1 (), brother, 6% is the laser beam output by the objective lens is human% of laser light G. As a result, changes occur through the material. For example, as shown in Figure 6, during the period of the peak power laser beam 44a output from the J7 round, when the output of the light 2 Chen oscillator changes from Pu to pm (& lt p), 'When the μ is low, the peak power beam is 45a.) And the laser beam with the transmitted pulse width maintained at Ws ^ The laser beam 44h output by the external laser oscillator instantly reduces the beam transmission rate to 0 At%, the beam transmission path pd is obtained, and the pulse width is maintained at a variable power as described above in this embodiment 45b. Beam transmission rate, get the sound of any sound ^^ is the laser light output by the optical trapping oscillator of the control optical system. ^ Duren in order to change the 'maximum peak power: ί, serve any laser Laser light emitted by the pulsator [take ^ = punch width is determined by ά · the peak power of the oscillating fort can not be changed to more than the above using the optical system = upper two beam transmission rate and pulse width method reach rate The objective lens 33 performs the phase-transmission of the laser beam that can be changed at any time as shown in the figure. ^ 33 is composed of: optical high-speed switching element to 34d; transmittance If: h transparent mirror ..., coffee and damper. In order to fix the two, the peak power and pulse width of the laser beam of the objective lens 33 can be reduced, and it is assumed that the high-speed switching element is turned on (ON), and the light is shifted.

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Page 28 1221791 V. Description of the invention (24)-First, when the switching element 34a is in the ON state, the laser beam 6b directly forms the laser beam 3 7a and is transmitted to the switching element 3 4c. If the switching element 34c is turned OFF at this time, the laser beam 37a is directly transmitted to the next switching element 3 4 d. When the switching element 34d is switched from 0FF to FF instantaneously during beam transmission, the laser beam during the OFF period will form 7b, but the laser beam between 0_ will be deflected and irradiated to the damper 3 6 . When the OFF time is short, a laser pulse 7 b 1 with a high peak power and a short pulse can be obtained as a result. Then, when the switching element 34a is turned OFF and the switching element 3 is "ON", the laser beam 6b will be deflected by the switching element 34a through the switching element 34a and transmitted to the translucent mirror 35a. Assume For example, when the transmissivity of the translucent mirror 353 is 50%, the laser 3 7b will correspond to the peak power 7b, form a half of the laser with the same pulse width, and turn on at 34c (0NM operation, as a result, a laser beam 37b is obtained. The deviation is transmitted to the switching element 34c and transmitted to the switching element 3 4 d. The switching element 3 4 d performs the same pulse 7b2 as described above.

Then 'when the switching elements 3 4 a, 6b are turned off (0FF) through the switching elements 34a, 34b 35b ° 34b, the laser beam is transmitted to the translucent mirror. The laser beam and the laser light are assumed to pass through the translucent mirror 35b2. For example, when the rate is 25%, 37c will correspond to the peak power 6b, forming 1/4 and the pulse width phase

314581.ptd

1221791 V. Description of the invention (25) bundle. After that, the laser beam 3 7 c is transmitted to 龆 M ^ ^ 34d to perform the same operation as described above = 34d. And when the switching element 34d is turned on i): =: Act. That is, the switching element, u I shoots at the damping cry q fi. When the animal is turned on for a long time, the laser pulse 7b3 of w results. The peak power is low and the pulse width is long. 叮: The above description describes the method of controlling the _peak power, but the nm method controls 2 or more peak powers to obtain !!!, the peak! Laser pulse with power and pulse width. In the case of the palladium type, the above objective lens is inserted into the optical system, and the laser beam output from the laser resonator is changed by switching the ON / OFF of the light to ON / OFF, which has an arbitrary peak power and pulse width. Laser pulse. The above-mentioned optical system is mounted in the laser processing system shown in FIG. 5: the same effect as that shown in the first application mode can be obtained, and the material and material composition of the printed wiring board are matched to make the The laser power φ, the value of power and pulse width, and the beam dwell time are optimized for each pulse ', and the effect of improving processing quality and productivity can be obtained. In addition, it is also possible to combine the above-mentioned optical system with the laser oscillator described in the first embodiment to form a laser processing system (Fig. 9). Thereby, the change in the peak power and pulse width of the laser beam can be made more detailed 'and the change amplitude can be made larger. Therefore, the laser processing system used above can further expand the selection range by matching the material and materials of the printed wiring board to make the laser beam peak.

314581.ptd Page 30 1221791 V. Description of the invention (26) value and power and pulse width, the beam energy in each pulse ^ In order to optimize even the complex material structure, productivity can be reduced. Effect. Improving Processing Quality and Production

Page 311221791 V. Description of the invention (27) In the third irradiation, the peak power of the laser beam output by the laser oscillator 2 C is reduced and irradiated. With this kind of control, it can be the same as the first embodiment The state is the same, and the effect of improving the processing quality is obtained. The fourth embodiment. Figures 11 and 12 are related to the fourth embodiment. Figure 11 is a schematic diagram illustrating the laser processing system of the present invention, and Figure 12 is a diagram illustrating control. The schematic diagram of the device of the laser pulse waveform of the present invention. In Fig. 11, 46a to e are discharge command pulse groups, and 47a to e are discharge power pulse groups '4 8a to e are input discharge hopes' 4 9a to e are output laser beam energy. The basic idea of this embodiment mode is focused on, as explained in the first embodiment mode, the laser beam 6e output from the laser oscillator 2E in FIG. 11 is maintained when the resonator loss is kept constant. It is determined by the average discharge power density and discharge width, but it is also suitable for laser oscillation. That is, in the outline operation, an arbitrary laser irradiation pattern 8e can be obtained by controlling the laser pulse waveform shown in Fig. 12. The operation of Fig. 12 will be described below. In addition, the mode shown in Figure 12 is suitable for: the basic idea of the first implementation mode, that is, maintaining the resonator loss constant, and controlling the peak power and pulse by the average discharge power density and discharge width, respectively Width person. In addition, as in the first embodiment, a specific control method is a method in which the frequency of the AC power source is adjusted to change the average discharge power density, and the input power time is changed to change the discharge width. First, the discharge command pulse 4 6 a is supplied at a high frequency.

314581.ptd Page 32 1221791 V. Description of Invention (28) The number of discharge power pulses input during (28) will increase, and 48a with high average discharge power density can be obtained. For this discharge energy 4 8 a (N lx T1) after the laser oscillation delay L1, a beam energy 49a (Plx W1) with a high peak power is output. Then, in the case of no time difference (beam irradiation rest time), the discharge command pulse 46 which is slightly reduced in frequency is continuously supplied, and the discharge power pulse 4 7 b is input to obtain the discharge energy 4 8 b (N 2x T 2), Then, without the laser oscillation delay, the previous 49a is connected to output the beam energy 49b (P2x W2). In the same manner, after continuously supplying the discharge command pulses 46c, 46d, and 46e without a time difference, the discharge energy 47c (N3x T3), 47d (N4x T4), 47e (N5x T5) is obtained, and the previous 49b, and output beam energy 49c (P3x W3), 49d (P4x W4), 49e (P5x W5). As a result, it is possible to obtain a laser pulse waveform with a mixture of five arbitrary peak powers. In addition, as in the second embodiment, the obtained laser irradiation shape 8e is formed into a light beam by the optical system 3E, or an appropriate one is used. The optical system changes the laser beam waveform so as to form the laser irradiation pattern 9e. That is, the laser pulse waveform of the above-mentioned mixed multiple peak powers is obtained by controlling the switching operation of the objective lens for controlling the laser beam waveform of T in the second embodiment in the middle of vibration. ΰ As mentioned above, by applying the same concept as the first and $ 2 implementation types: "On the way to laser gain", laser pulses with a variety of peak powers can be obtained. However, compared to the second implementation type State, in the absence of high-speed and stable control

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1221791 V. Description of the invention (29) The situation that will cause unevenness of each pulse may increase. Next, the force of using the laser processing system described above will be described. The working method of this embodiment is applicable to the case where a more detailed laser pulse waveform condition is set in the processing method of the first embodiment. First, it is a schematic diagram of a laser beam irradiation form suitable for the laser processing system of the present invention. > 知 # In Fig. 13, the beam energy Ei of the laser beam irradiated at the i-th time is assumed to be the p-iv peak power of the v-th peak power among the u-type peak powers, and When the time width held by P iv is assumed to be wiv, the following formula can be obtained

Ei = 2 ^ Piv x Wiv) · · · Formula 1 〇V-1 Here, P iv and wi V of the present invention are control parameters that can be switched instantaneously (less than 1/2 of the laser pulse width). ; Use the above method to switch according to the processing content. In Fig. 13, S4 and S42 are respectively the laser beams of P1 lx WU and P21x W21 in the first irradiation, and S43 is the laser beams of P21 X W21 in the second irradiation. Explain the operation. The irradiation beams S41 to S43 are applicable to the respective irradiation beams S 3 1 to S 3 3 shown in the first embodiment. That is, S41 is the peak power is high and the time width is short. S42 is the peak power is low and the time width is long, while S43 is the peak power is slightly higher than S42 and the pulse width

314581.ptd P.34 In addition, the number of irradiations of the S41a and S4 2 series phases can be reduced from 3 to 2 times. V. Description of the invention (30) M laser beam. With different laser beams, ^ 工 + "can be processed in the same way as in the first implementation method =: !! _ through plus: surface copper to U grease lla 'and no damage by S43 _ Remove resin residue. In the same way, the laser pulse mouth has the effect of reducing the resting time of the beam irradiation. ^ The application type can further shorten the processing time required for n holes. For example, in the example of the first embodiment, the processing is performed in the first time. This type of burst protection is expected to shorten and increase productivity by 1.5 times. As mentioned above, by using the control laser pulse access system, the processing quality can be improved, and the effect of increasing the productivity can be achieved by reducing the dwell time of irradiation. In addition, there are two effects of obtaining the quality and productivity of traditional laser processing materials.

As mentioned above, the laser processing device and substrate of the present invention perform hole processing as described above. In the case where the plus I is punched out by S 4 2 and 3 foils 1 2 b, the shape requires L for each hole, compared with the first solid. The processing time is 10 seconds, compared with 5 seconds. The laser processing system of L-shape is t (reduced by laser radiation, which cannot be achieved by the system is suitable for printing

314581.ptd Page 35 1221791 Brief description of the drawings [Simplified description of the drawings] The first diagram is a model diagram for explaining the laser processing system of the first embodiment. Fig. 2 is a schematic diagram showing a device for controlling a laser irradiation form in the laser processing system of the first embodiment. Fig. 3 is a schematic diagram showing a laser irradiation pattern used in the laser processing method of the laser processing system of the first embodiment. Fig. 4 is a schematic diagram for explaining a laser processing state of the laser irradiation form in Fig. 3; Fig. 5 is a schematic diagram for explaining the laser processing system of the second embodiment. FIG. 6 is a state diagram showing a change in a beam transmission rate of an objective lens. FIG. 7 is a configuration diagram showing the configuration of the objective lens. Fig. 8 is a state diagram showing changes in the beam transmission rate and pulse width of the objective lens. Fig. 9 is a schematic diagram for explaining the laser processing system of the second embodiment. Fig. 10 is a model diagram for explaining the laser processing system of the third embodiment. Fig. 11 is a model diagram for explaining the laser processing system of the fourth embodiment. Fig. 12 is a schematic diagram showing a device for controlling a laser irradiation form in a laser processing system of a fourth embodiment. Figure 13 shows the laser processing system of the fourth embodiment applied to bursts.

314581.ptd Page 36 1221791 Schematic description of the pattern showing the laser beam irradiation mode during processing. Fig. 14 is a schematic diagram for explaining a hole-cutting process of a general printed wiring board. Fig. 15 is a schematic diagram for explaining a conventional laser processing system for punching a printed wiring board. Fig. 16 is a cross-sectional view of a brushed wiring board for explaining the processing quality of laser drilling. Fig. 17 is a configuration diagram showing the configuration of an objective lens composed of a mask and a collimator lens. Figure 18 is a diagram illustrating the structure of a carbon dioxide laser oscillator. Fig. 19 is a diagram illustrating a laser irradiation pattern of a burst processing of a conventional open-hole laser processing method of a printed wiring board. Fig. 20 is a laser irradiation pattern used to explain the cyclic processing of the conventional laser processing method of the open-hole laser processing of the printed wiring board. Fig. 21 is a schematic diagram showing a conventional laser irradiation pattern and a sectional view of a printed wiring board. Fig. 22 is a schematic diagram showing a conventional laser irradiation pattern and a sectional view of a printed wiring board. Fig. 23 is a schematic diagram showing a conventional laser irradiation pattern and a sectional view of a printed wiring board. Fig. 24 is a sectional view showing a printed wiring board of conventional processing quality. 1 printed wiring board

314581.ptd Page 37 1221791 Brief description of the drawings 2, 2C, 2D, 2E Laser oscillator 3, 3C, 3D, 3E Optical system 4 Processing table 5 Control device 6, 6a, 6c, 6d, 6e, 7, 7a , 7c, 7d, 8c, 8d, 9, 9a, S31 to S33, 44a, 44b Laser beams 8, 8a, 8e, 9, 9a, 9e, 1 0 Laser irradiation form 1 la Insulating resin 12a, 12b, 13 Surface copper foil, inner copper foil 14a Blind hole 2 0 Processing target position 33 Objective lens 34a, 34b, 34c, 34d Switching element 35a, 35b Translucent mirror 36 Damper beam Beam e Put e Put e Put e Lei Lei 37a, 37b, 37c 1 4 1 a, 4 1 b, 4 6 a to 42a, 42b, 47a to 43a, 43b, 48 a to 44a, 44b, 49 a to 4 5 a, 4 5 ba 1 to a3 fh, fl Iu, Id electric command pulse group electric power pulse group electric energy beam energy beam beam processing section frequency power supply frequency efficiency discharge power density

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Claims (1)

1221791 — VI. Scope of patent application _ 1. A type of laser processing system discharge means i pulse 糸: U is switched by a predetermined frequency and the laser strikes the Aihua technology between the electrodes. The laser is capable of forming a variable pulse laser vibrator; the laser beam output by the light of the workpiece ^ Beiyi guides the system. 2. If the scope of the patent application is all with a switching device | ―Each system, in which the laser beam of the optical system is cut off $ 3. It can be output by passing through the laser oscillator 3. The variable should be laser beam The peak power is changed to an appropriate path of the filter member, and a laser processing wire with a different beam transmittance. The laser beam generated by the Zhenbao output laser H has a switching vibration between the two electrodes, which has a switching shock; a laser oscillator; the above laser beam, 3 is changed from the output rate transmitted by the delta laser oscillator to a variable The laser beam should be guided to 4 by the filter components with different peak powers of the laser beam, f, ^ :, and the optical system of the object to be processed by the beam transmittance, and the laser beam should be guided to 4. 5. The medium is the laser processing system that uses the switching device or :, and the optical path of the optical component is turned off at the same time when the switch is switched to the pulse width that should pass through the filter beam. A laser processing method that controls the laser light that is oscillated by pulses. The discharge command pulse is used to change the use of a predetermined frequency. The use of the laser beam can cause the laser beam to discharge electricity and generate laser vibration. Vessel On page 40, the laser processing method for processing the laser beam of the patent scope 1, m: It can match the material and thickness of the workpiece in the range below the maximum oscillation frequency of the laser oscillator in each pulse. : Three conditions including the peak power and pulse of multiple laser pulses irradiated by the knife change, and the rest time of the beam irradiation. . = 1 Lee_ Laser processing method of 5 items, in which, when the body layer is removed, the processing is performed by the M-th punch with a short pulse width of 1 to 15 # S when the output of the laser peak peak power is close to the maximum power of the laser oscillator. 'And when removing the insulating layer, the processing is performed by the second pulse having the peak power output of 1/2 to 1/10 of the first pulse palace and a long pulse width of 16 to 20 bs. • The laser processing method according to item 5 of the scope of patent application, wherein, by switching the discharge command pulse, the peak power is set to a variable peak power during the laser output period of 1 pulse, and the pulse is used The laser beam that is rotated out is processed. For example, the laser processing method in the seventh scope of the patent application, which is based on a slightly maximum peak power of the laser oscillator and! The first field in a short time to 5 // s; and the peak power of approximately 1/2 to 1/10 in the first field and the second field in a long time from 16 to 2 0 // s 1 pulse laser output for processing. .ptd Page 41