Method for forming cutout or notch portion in printed circuit board by laser processing

Abstract

To form a cutout portion or the like at the design position of a printed circuit board according to the design dimensions.SOLUTION: In grooves 3, ..., and 7 having a substantially V-shaped vertical cross section formed by setting a target processing line S1 indicating the shape of a cutout portion 2 according to the design dimensions at the design position of a printed circuit board 1, and sequentially irradiating a plurality of auxiliary processing lines S2, ..., and S5 on the cutout portion 2 side with reference to the target processing line S1 with laser light from the auxiliary processing lines S5, ..., and S2 to the target processing line S1, among tapered surfaces 3a', ..., and 7a" forming the adjacent grooves 3, ..., and 7 having the substantially V-shaped vertical cross section, the shift amount is set within a range where adjacent tapered surfaces 3a" and 4a', ..., and 6a" and 7a' overlap, since the printed circuit board 1 is cut while the machining powder and steam are discharged toward the cutout portion 2 side by repeating the sequential processing from the position of the auxiliary processing line S5 farthest from the target processing line S1, the cut surface becomes smooth, and a semiconductor or the like can be accurately mounted on the cutout portion of the printed circuit board.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for forming cutouts or notches in a single-layer or multi-layer printed circuit board (hereinafter simply referred to as a "printed circuit board") by laser processing, the cutouts or notches being used for mounting semiconductors or other electronic components (hereinafter referred to as "semiconductors, etc.") with solder ball terminals on the printed circuit board. [Background technology]

[0002] In recent years, electronic products such as mobile phones and personal computers have become thinner and smaller while also achieving higher performance. For this reason, the printed circuit boards installed in such electronic products are required to be thin and compact as well as have high performance. As a result, when cutouts or notches are used to mount semiconductors and the like on the printed circuit boards, laser processing methods that enable more precise processing have come to be used (see Patent Document 1). In particular, semiconductors etc. mounted on a printed circuit board affect the thinning and miniaturization of the entire printed circuit board on which the semiconductors etc. are mounted, so high positional accuracy and dimensional accuracy are required for the cutouts and notches.

[0003] However, when forming a cutout or notch of a predetermined size at a predetermined position in a printed circuit board by laser processing, even if a cutout or notch is formed by irradiating a low-energy laser beam multiple times along a cutting line set at the predetermined position and with the predetermined size, it is not possible to process the cutout or notch beyond a certain depth, and as a result, the cutout or notch cannot be formed. Therefore, the laser beam used must have a relatively high energy intensity. However, when irradiating a laser beam with a relatively high energy intensity, the heat of the irradiated laser beam causes explosive generation of processing powder and steam from the base material of the printed circuit board at the cut portion of the printed circuit board. As a result, the cut surface of the printed circuit board becomes rough and loses its smoothness, and processing powder and steam adhere to the surface of the printed circuit board. Therefore, since the cut surfaces of the cut parts made by the laser processing are not smooth, even if an attempt is made to mount a semiconductor or the like in the cutout or notch part, it is not possible to attach it in an accurate position, and the high positional accuracy and dimensional accuracy required for the semiconductor or the like cannot be ensured.

[0004] Furthermore, during laser processing of the printed circuit board, the laser light reaches not only the printed circuit board but also the lower plate, causing processing powder and steam to adhere to the surface of the printed circuit board, which could lead to failure of the printed circuit board or the electronic product to which the printed circuit board is attached. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2003-17828 A Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved is that when cutouts and notches used for mounting semiconductors and the like in a printed circuit board are formed by laser processing, the heat of the laser light causes the smoothness of the cut surface at the cut part to be lost, making it impossible to ensure the high positional accuracy and dimensional accuracy required when semiconductors and the like are mounted in the cutouts and notches of the printed circuit board, and further, if processing powder and steam generated from the printed circuit board and the base plate on which the printed circuit board is placed adhere to the surface of the printed circuit board, there is a risk of causing failure not only of the printed circuit board but also of the electronic product to which the printed circuit board is attached. [Means for solving the problem]

[0007] The first feature is, When forming cutouts or notches (hereinafter referred to as "cutouts, etc.") in a printed circuit board by laser processing, A processing line (hereinafter referred to as a "target processing line S1") indicating a cutout portion or the like of a design dimension is set at a design position on the printed circuit board, Using the target processing line S1 as a reference, multiple processing lines (hereinafter referred to as "auxiliary processing lines S2, ..., Sn", where n is the "total number of target processing lines and auxiliary processing lines") are set on the opposite side to the side that will become the product after laser processing. In the target processing line S1 and the auxiliary processing lines S2, ..., Sn, the respective separation distances (hereinafter referred to as "shift amounts") between the mutually adjacent target processing lines S1 and the auxiliary processing lines S2, ..., Sn-1, Sn are set to a range in which adjacent tapered surfaces of the tapered surfaces constituting the adjacent grooves having a substantially V-shaped vertical cross section overlap with each other in the grooves having a substantially V-shaped vertical cross section formed by sequentially irradiating the laser light from the auxiliary processing lines Sn, Sn-1, ..., S2 to the target processing line S1, By repeating laser processing sequentially from the position of the auxiliary processing line Sn, which is the farthest from the target processing line S1 among the auxiliary processing lines S2, ..., Sn-1, Sn, to the position of the target processing line S1 (hereinafter referred to as "one processing cycle"), a cutout portion or the like is finally formed by cutting the printed circuit board at the position of the target processing line S1.

[0008] Therefore, when laser processing is performed sequentially from the position of the auxiliary processing line Sn which is the furthest from the target processing line S1, the center of the irradiated laser light has the highest energy intensity, so that a groove having an approximately V-shaped vertical cross section is formed at the position of the auxiliary processing line Sn. The next auxiliary processing line Sn-1 is set at a shift position within the range in which adjacent tapered surfaces of the groove having an approximately V-shaped vertical cross section formed by irradiating laser light onto the auxiliary processing line Sn-1 overlap with each other, among the tapered surfaces that form the groove having an approximately V-shaped vertical cross section formed by irradiating laser light previously onto the auxiliary processing line Sn. Therefore, when laser light is irradiated to the position of the auxiliary processing line Sn-1, the tapered surfaces forming a groove having an approximately V-shaped vertical cross section formed by irradiating the position of the auxiliary processing line Sn-1 with laser light overlap and merge with adjacent tapered surfaces forming a groove having an approximately V-shaped vertical cross section formed by irradiating the position of the auxiliary processing line Sn with laser light, and although they have consecutive apexes at approximately the same depth positions, by performing multiple processing cycles, a groove having an approximately inverted trapezoidal vertical cross section is formed whose bottom surface in the printed circuit board is approximately flat. Furthermore, when the laser light is sequentially irradiated in the same manner from the position of the auxiliary processing line Sn-2 to the position of the target processing line S1, grooves having an approximately inverted trapezoidal shape in vertical cross section with apexes at approximately the same depth positions are formed in sequence, and wide grooves having an approximately inverted trapezoidal shape in vertical cross section with tapered surfaces are formed on the auxiliary processing line Sn side opposite the auxiliary processing line Sn-1, and on the target processing line S1 side opposite the auxiliary processing line S2. By forming this wide groove having a generally inverted trapezoidal cross section, the groove having a generally V-shaped cross section formed at each processing line Sn, ..., S1 can be gradually deepened by repeating multiple processing cycles of laser processing from the position of the auxiliary processing line Sn to the position of the target processing line S1, and the printed circuit board can finally be cut at the position of the target processing line S1. In this case, the printed circuit board may also be cut at the positions of the auxiliary processing lines Sn, ..., S2 in some cases, but these cut positions become unnecessary parts as cutouts, etc., so that the printed circuit board is finally cut at the position of the target processing line S1, and a cutout or the like according to the design dimensions is formed at the specified design position of the printed circuit board. Here, the cutting of the cutout portion in the printed circuit board 1 is performed by repeating a processing cycle in which the auxiliary processing lines Sn, ..., S2 and the target processing line S1 are sequentially irradiated with laser light. Therefore, by lowering the energy intensity of the laser light irradiated at one time, the smoothness of the tapered surface, which is the cut surface of the printed circuit board, can be ensured.

[0009] The laser processing at the position of the target processing line S1 is performed in the range where the adjacent tapered surfaces of the grooves having a substantially inverted trapezoidal cross section formed on the printed circuit board by the laser processing at the positions of the auxiliary processing lines Sn to S2 overlap. At this time, the grooves having a substantially inverted trapezoidal cross section, which are formed by irradiating the positions of the lines Sn to S1 with the laser light and which are continuous grooves having a substantially V-shaped cross section, are biased toward the auxiliary processing line Sn when viewed from the side of the target processing line S1. Therefore, the processing powder and steam generated from the printed circuit board by the irradiation of the laser light are discharged more toward the auxiliary processing line Sn side, that is, the side that is not to be made into a product, such as the cutout part of the printed circuit board, while being less on the side of the printed circuit board that will be the product, so that sagging is less likely to occur on the side of the printed circuit board that will be the product, and the adhesion of processing powder and steam to the surface of the printed circuit board can be prevented.

[0010] The number of auxiliary processing lines will vary depending on the thickness and material of the printed circuit board, but 5 to 10 lines, including the target processing lines, is appropriate, mainly based on the balance between the working time and energy required for laser processing. In other words, if the total number of the target processing lines and auxiliary processing lines is less than five, the laser processing time will be shorter, but the position of the apex of the groove that is approximately V-shaped in vertical cross section that is formed when the laser light is sequentially irradiated from the auxiliary processing line Sn to the target processing line S1 must be made deeper, and the energy intensity of the laser light must be increased, which will result in a decrease in the quality of the cut surface and defects in the printed circuit board as a product. On the other hand, if the total number of the target processing lines and auxiliary processing lines exceeds 10, the shift amount between the target processing lines and the auxiliary processing lines becomes smaller, and the energy intensity of the laser light during laser processing can be reduced, but the number of repetitions of the processing cycle increases, resulting in a disadvantage that the working time increases.

[0011] In addition, in order to make the bottom surface of the groove having an approximately inverted trapezoidal shape in vertical cross section, which is formed by sequentially irradiating laser light from the position of the auxiliary processing line Sn to the position of the target processing line S1, approximately flat by performing the processing cycle multiple times, the above shift amount needs to be set so that, in each groove having an approximately V-shaped vertical cross section, which is formed by sequentially irradiating laser light from the auxiliary processing lines Sn, Sn-1, ..., S2 to the target processing line S1, adjacent tapered surfaces of the grooves having an approximately V-shaped vertical cross section overlap with each other. That is, if the shift amount of each line Sn to S1 is outside the range where the adjacent tapered surfaces of the adjacent grooves having a substantially V-shaped cross section overlap each other in the grooves having a substantially V-shaped cross section formed by sequentially irradiating the auxiliary processing lines Sn, Sn-1, ..., S2 to the target processing line S1 with the laser light, sequentially irradiating the auxiliary processing lines and the target processing lines with the laser light is merely irradiating the laser light to the positions of the processing lines on the surface of the printed circuit board, and the grooves having a substantially V-shaped cross section with the same shape and depth are machined at each processing line position. Therefore, it is impossible to cut the printed circuit board by irradiating the laser light. The shift amount corresponds to about ±30% based on the spot diameter of the laser light, which usually accounts for 86% of the energy intensity of the laser light. Here, the shift amount varies depending on the material being processed. For example, if the material being processed is hard, the shift amount is adjusted to be narrower (negative side), and if the material is soft, the shift amount is adjusted to be wider (positive side).

[0012] Furthermore, the processing cycle in laser processing will vary depending on the thickness and material of the printed circuit board, but 20 to 100 cycles is appropriate, mainly considering the balance between the energy required for laser processing, working time, and the quality of the cut surface of the printed circuit board. That is, if the processing cycle is less than 20 cycles, the working time required for laser processing can be shortened, but the energy intensity of the laser light irradiated in the laser processing must be increased, and if the energy intensity of the laser light is increased, the quality of the cut surface deteriorates and defects occur in the printed circuit board as a product. On the other hand, if the processing cycle exceeds 100 cycles, the energy intensity of the laser light can be reduced and the deterioration of the quality of the cut surface can be prevented, but the working time required for laser processing increases unnecessarily, resulting in an increase in manufacturing costs.

[0013] Based on the first characteristic, the second characteristic is as follows: On the surface of the lower plate on which the printed circuit board is placed, relief grooves are provided immediately below the positions of the target processing line S1 and the auxiliary processing lines S2, . . . , Sn which are set on the printed circuit board.

[0014] Therefore, on the surface of the lower plate on which the printed circuit board is placed, escape grooves are arranged directly below the positions of the target processing line S1 and auxiliary processing lines S2, ..., Sn set on the printed circuit board.Therefore, when the laser light finally cuts the printed circuit board at the position of the target processing line S1, or when cutting of the printed circuit board also occurs at the positions of the auxiliary processing lines Sn, ..., S2, the large amount of processing powder and steam generated by being irradiated onto the lower plate can be contained within the escape grooves, thereby making it possible to suppress the ejection of powder and steam from the cut portion of the printed circuit board. As a result, it is possible to prevent the powder and vapor from adhering to the surface of the printed circuit board, which can cause damage to not only the printed circuit board but also to electronic products to which the printed circuit board is attached.

[0015] Here, the appropriate depth and width dimensions of the escape groove disposed on the surface of the lower plate are about 1 mm each, taking into consideration the balance between interference with the suction port that sucks and fixes the printed circuit board placed on the lower plate, the amount of processing powder and steam generated from the lower plate when irradiated with the laser light, and how to deal with misalignment when the printed circuit board is placed on the lower plate. That is, if the depth and width dimensions of the relief groove are significantly smaller than 1 mm, there is less interference with the suction port that adsorbs and fixes the printed circuit board placed on the lower plate, so the design freedom of the relief groove is high, but there are disadvantages in that it is not possible to reliably contain the large amount of machining powder and steam generated from the lower plate by irradiation with laser light, and it is also difficult to deal with the misalignment between the lower plate and the printed circuit board when the printed circuit board is placed on the lower plate.On the other hand, if they significantly exceed 1 mm, the machining powder and steam generated from the lower plate by irradiation with laser light can be reliably contained in the relief groove, and the misalignment that occurs when the printed circuit board is placed on the lower plate can be reliably dealt with, but there is an increased interference with the suction port that adsorbs and fixes the printed circuit board placed on the lower plate, so the design freedom of the relief groove is low.

[0016] Furthermore, the width and depth of the escape groove arranged in the lower plate can be regarded as an extremely large space when viewed from the shift amount of the target processing line and auxiliary processing line set on the printed circuit board, and there is a possibility that it will be able to adequately accommodate the processing powder and steam generated from the lower plate by the irradiation of the laser light, so there is no particular need for a mechanism to actively exhaust the processing powder and steam contained within the escape groove to the outside. However, when a cutout is formed in a printed circuit board, one side of the cutout also becomes an end face of the printed circuit board, which means that both ends of the escape groove are necessarily open, and the machining powder and steam are naturally discharged to the outside through the exhaust ports opening at both ends of the escape groove. Effect of the Invention

[0017] In the present invention, when cutting a printed circuit board, the tapered surface of the groove with a substantially V-shaped vertical section generated by laser processing at the position of the target processing line is combined with the groove with a substantially V-shaped vertical section formed continuously by the irradiation of the laser light at the positions of the auxiliary processing lines, and as a result, it becomes a part of the groove with a substantially inverted trapezoidal vertical section. Therefore, by irradiating the laser light with low energy intensity many times, it is possible to form the cutout part of the printed circuit board by the laser light, and a smooth cut surface can be obtained. Furthermore, the processing powder and steam generated from the printed circuit board by the irradiation of the laser light at the positions of each processing line are mainly discharged to the auxiliary processing line side, which is the side that does not become the product, so that the smoothness of the tapered surface formed at the cut surface of the printed circuit board that becomes the product is not lost, and the adhesion of processing powder and steam to the surface of the printed circuit board is prevented, so that the cutout part of the printed circuit board is formed at the designed position as designed, and the failure of the printed circuit board is prevented. As a result, it is possible to mount semiconductors and the like with high positional accuracy and high dimensional accuracy, and it has an excellent effect of improving the yield of printed circuit boards in which cutout parts and the like are formed by laser processing.

[0018] Furthermore, even if a large amount of machining powder or steam is generated from the lower plate when the lower plate is irradiated with a laser beam, the large amount of machining powder or steam is contained within the relief groove of the lower plate, so that the machining powder or steam is prevented from escaping from the cut portion of the printed circuit board. As a result, the adhesion of machining powder or steam to the cut surface of the printed circuit board as well as to the surface of the printed circuit board is prevented, which has the excellent effect of preventing failure of not only the printed circuit board but also electronic products. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a front view of a printed circuit board to be cut out. [Diagram 2] FIG. 2 is a front view of the printed circuit board on which the notch is to be cut. [Diagram 3] FIG. 3 is an enlarged cross-sectional view of a main part taken along line AA in FIG. [Figure 4]FIG. 4 is a schematic diagram showing a machining cycle for a printed circuit board. [Diagram 5] FIG. 5 is a schematic diagram showing the final processing cycle for forming cut-outs in a printed circuit board. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] When forming cutouts or notches used for mounting semiconductors or the like on a printed circuit board by laser processing, a target processing line set for forming cutouts or the like according to the design dimensions at the design position of the printed circuit board is used as a reference, and multiple auxiliary processing lines are set on the opposite side of the part that will become a product after the laser processing by sequentially irradiating laser light from the auxiliary processing line to the target processing line, with a shift amount within a range in which adjacent tapered surfaces of adjacent grooves having a substantially V-shaped vertical cross section overlap each other. Then, by repeating sequential laser processing from the auxiliary processing line farthest from the target processing line to the target processing line, the printed circuit board is finally cut at the target processing line while discharging processing powder and steam generated by the laser processing to the auxiliary processing side, and a cutout or notch is formed according to the design dimensions at the design position of the printed circuit board. EXAMPLES

[0021] FIG. 1 shows a 0.8 mm thick printed circuit board 1 made of glass fiber reinforced epoxy resin, in which a cutout 2 to be used for mounting a semiconductor or the like is to be formed by the method of forming cutouts and notches by laser processing in the printed circuit board of the present invention.

[0022] In implementing the present invention on the above-mentioned printed circuit board 1, the printed circuit board 1 is placed on a lower plate 9 and fixed to a processing table (not shown) in a laser processing machine (not shown), and then laser light is irradiated.

[0023] Furthermore, on the surface of the lower plate 9, directly below the target processing line S1 and auxiliary processing lines S2, ..., S5 which are set in a rectangular shape on the printed circuit board 1 as described below, an escape groove 10 of the same shape and with a width and depth of 1 mm is arranged.

[0024] Therefore, when carrying out the method of forming cutouts and notches by laser processing in a printed circuit board of the present invention to form a cutout 2 at the designed position on the printed circuit board 1 according to the designed dimensions, the process is as follows.

[0025] First, in the printed circuit board 1, a target processing line S1 is set, which indicates the shape of the cutout portion 2 to be formed in the designed position according to the designed dimensions. Then, using the target processing line S1 as a reference, four auxiliary processing lines S2, ..., S5 are set on the side to be cut out as the cutout portion 2 by laser processing, that is, on the side that does not become the product of the printed circuit board. At this time, the shift amount, which is the distance between the five target processing lines S1 and the auxiliary processing lines S2, ..., S5, must be set to a range in which the adjacent tapered surfaces 3a" and 4a', 4a" and 5a', ..., 6a" and 7a' overlap each other among the tapered surfaces 3a', 3a", ..., 7a', 7a" that form the adjacent grooves 3, 4, 5, 6, 7 that are approximately V-shaped in vertical cross section, which is described later, in the grooves 3, 4, 5, 6, 7 that are approximately V-shaped in vertical cross section, and is set to 7 μm in this embodiment. Note that the shift amounts do not have to be all the same numerical value, but are all the same in this embodiment. Then, laser processing is performed sequentially from the position of the auxiliary processing line S5, which is the furthest from the target processing line S1, to the position of the target processing line S1 among the total of five target processing lines S1 and auxiliary processing lines S2, ..., S5 set on the printed circuit board 1. The laser to be irradiated is a UV laser (not shown), and the irradiation conditions are a laser light spot diameter of 15 μm, a laser frequency of 50 kHz, an energy of 100 μj, a processing pitch of 10 μm, and a processing cycle of 50 times. Therefore, at the position of the auxiliary processing line S5, the heat of the laser light causes processing powder and steam to be generated from the printed circuit board 1, and the center of the laser light with the highest energy intensity, i.e., the center of the laser light, reaches the deepest position of the printed circuit board 1, forming a groove 3 having an approximately V-shaped cross section and two tapered surfaces 3a', 3a'', with the center of the laser light at its apex. Then, by sequentially performing laser processing on the positions of the auxiliary processing lines S4, ..., S2 and the target processing line S1, laser light is irradiated onto the positions of the auxiliary processing lines S4, ..., S2 and the target possible line S1, respectively, so that the center of the laser light reaches a position of approximately the same depth, and grooves 4, ..., 7 having approximately V-shaped longitudinal sections are formed with the center of the laser light as the vertex. In this case, the shift amounts between the auxiliary processing lines S5, ..., S2 and the target processing line S1 are set in the range in which the adjacent tapered surfaces 3a', 3a", ..., 7a', 7a" constituting the adjacent grooves 3, 4, 5, 6, 7 having an approximately V-shaped vertical cross section overlap with each other, among which the tapered surfaces 3a" and 4a', 4a" and 5a', ..., 6a" and 7a' form the adjacent grooves 3, 4, 5, 6, 7 having an approximately V-shaped vertical cross section. Therefore, the adjacent grooves 4, ..., 7 having an approximately V-shaped vertical cross section formed by the irradiation of the laser light merge with each other to form a groove 8 having an approximately inverted trapezoidal vertical cross section and a substantially flat bottom surface, which is widely open toward the auxiliary processing line S5 side when viewed from the target processing line S1 side, by performing multiple processing cycles. Then, when cutting out the cutout portion 2 from the printed circuit board 1, a processing cycle in which the auxiliary processing lines S5, ..., S2 and the target processing line S1 are sequentially irradiated with laser light is repeated 50 times. Therefore, by lowering the energy intensity of the laser light irradiated each time, it is possible to ensure the smoothness of the tapered surface 7a", which is the cut surface of the printed circuit board 1 that becomes the product. In addition, the machining dust and steam generated by the irradiation of the laser beam on the printed circuit board 1 are discharged more from the auxiliary processing line S5 direction side and less on the opposite side. As a result, when laser processing is performed sequentially from the position of the auxiliary processing line S5 to the position of the target processing line S1, the machining dust and steam generated from the printed circuit board 1 by the irradiation of the laser beam are mainly discharged on the auxiliary processing line S5 side, i.e., the side that is not to be made into a product, such as the cutout portion 2 of the printed circuit board 1, and are extremely small on the side of the printed circuit board 1 that will be the product, so that machining dust and steam do not adhere to the cut surface or surface on the side of the printed circuit board 1 that will be the product, and the tapered surface sagging 12 caused by them is generated exclusively on the tapered surface 3a' on the side that will not be made into a product. As a result, when the printed circuit board 1 is finally cut at the position of the target processing line S1, the cutout portion 2 having the above-mentioned tapered surface 7a'' as a cut surface can be formed at the designed position of the printed circuit board 1 according to the designed dimensions, and failure of the printed circuit board 1 itself and the semiconductors mounted thereon can be prevented. In this way, when the printed circuit board 1 is finally cut at the position of the target processing line S1, the cutout portion 2 having the tapered surface 7a'' as a cut surface can be formed in the designed position of the printed circuit board 1 according to the designed dimensions. Moreover, since the cut surface of the cutout portion 2 does not lose its smoothness, a semiconductor or the like can be accurately mounted in this cutout portion 2.

[0026] Furthermore, when the printed circuit board 1 is cut by laser irradiation, even if a large amount of machining powder and steam is generated by the laser light being irradiated onto the lower plate 9, the surface of the lower plate 9 has escape grooves 10 arranged directly below the total of five target machining lines S1 and auxiliary machining lines S2, ..., S5 set on the printed circuit board 1. Therefore, the above-mentioned machining powder and steam are contained within the escape groove 10 and do not spray out from the cut portion of the printed circuit board 1, and can be reliably prevented from adhering to the cut portion or surface of the printed circuit board 1. In addition, the width and depth of the escape groove 10 arranged in the lower plate 9 is 1 mm, which is much larger than the width of the five target processing lines S1 and auxiliary processing lines S2, ..., S5 in total, and the escape groove 10 itself can be regarded as an extremely large space, so there is no need for a mechanism to release processing powder and steam to the outside.

[0027] Furthermore, when forming the cutout portion 2' in the printed circuit board 1, due to its structure, exhaust ports 11 that open to the outside are necessarily formed at both ends of the escape groove 10', so that the machining powder and steam contained within the escape groove 10' are naturally discharged to the outside through the exhaust ports 11. [Industrial Applicability]

[0028] Since the printed circuit board is cut by repeating a processing cycle in which laser processing is performed sequentially from the auxiliary processing line set on the printed circuit board toward the target processing line, cutouts and the like of accurate dimensions are formed at accurate positions, and the smoothness of the tapered surface of the cut portion is ensured. Therefore, cutouts and notches of the designed dimensions can be formed at the designed positions of printed circuit boards made of any material, so that semiconductors and the like can be accurately mounted in the cutouts and notches, and the present invention can be applied to a device that performs laser processing on printed circuit boards to be attached to any electronic product. [Explanation of symbols]

[0029] 1 Printed circuit board 2 Cutout 2' Notch 3, 4, 5, 6, 7 Groove with a roughly V-shaped vertical section 3a', 3a” tapered surface 4a', 4a” tapered surface 5a', 5a” tapered surface 6a', 6a” tapered surface 7a', 7a” tapered surface 8 Groove with a roughly inverted trapezoidal cross section 9, 9' lower plate 10, 10' Relief groove 11 Outlet 12 Whole S1 Target processing line S2, S3, S4, S5 Auxiliary processing lines

Claims

1. When forming a cutout or notch (hereinafter referred to as "cutout, etc.") in a printed circuit board by laser processing, A processing line (hereinafter referred to as a "target processing line S1") indicating a cutout portion or the like of a design dimension is set on the printed circuit board at a design position on the printed circuit board, Using the target processing line S1 as a reference, a number of processing lines (hereinafter referred to as "auxiliary processing lines S2, ..., Sn", where n is the "total number of target processing lines and auxiliary processing lines") are set on the opposite side to the side that will become the product after laser processing. In the target processing line S1 and the auxiliary processing lines S2, ..., Sn, the respective separation distances (hereinafter referred to as "shift amounts") between the mutually adjacent target processing lines S1 and the auxiliary processing lines S2, ..., Sn-1, Sn are set to a range in which adjacent tapered surfaces of the tapered surfaces constituting the adjacent grooves having a substantially V-shaped vertical cross section overlap with each other in the grooves having a substantially V-shaped vertical cross section formed by sequentially irradiating the laser light from the auxiliary processing lines Sn, Sn-1, ..., S2 to the target processing line S1, By repeating the laser processing from the position of the auxiliary processing line Sn, which is the farthest from the target processing line S1 among the auxiliary processing lines S2, ..., Sn-1, Sn, to the position of the target processing line S1 (hereinafter referred to as "one processing cycle"), the printed circuit board is finally cut at the position of the target processing line S1 to form a cutout portion, etc.

1. A method for forming a cutout or notch in a printed circuit board by laser processing, comprising:

2. On the surface of the lower plate on which the printed circuit board is placed, relief grooves are provided immediately below the positions of the target processing line S1 and the auxiliary processing lines S2, ... Sn-1, Sn set on the printed circuit board.

2. A method for forming a cutout or notch in a printed circuit board by laser processing according to claim 1.

Images