JP6106868B2 - Via hole forming method and via hole forming apparatus - Google Patents

Description

  The present invention relates to a via hole forming method and a via hole forming apparatus when forming a blind via hole (BVH) on a base material such as a printed circuit board.

  Conventionally, a method of forming a via hole in a printed circuit board by removing a conductor layer such as a copper foil formed on the insulating layer of the printed circuit board together with the insulating layer by using, for example, a UV laser is known (Patent Document 1). reference). In this method, a plurality of circular holes are connected by a laser to form a via hole having a large hole diameter as a whole in a flat shape, an elliptical shape, or a rectangular shape.

  When a via hole is formed using a laser in this way, it is necessary to remove the conductor layer after condensing the laser beam to a spot size of about 20 μm to 30 μm to increase the beam energy. In order to form, the laser beam is repeatedly irradiated over the formation range a plurality of times.

JP 2002-64274 A

  In the conventional forming method described above, a via hole having a large hole diameter is formed by irradiating the conductive layer with a condensed laser beam having a small spot diameter a plurality of times. For this reason, there is a problem that the formation time of the via hole becomes longer as a whole, and the productivity may be lowered.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a via hole forming method and a via hole forming apparatus capable of solving the above-described problems caused by the prior art, shortening a via hole formation time by a laser, and improving productivity.

  In the method for forming a via hole according to the present invention, the first conductor layer is formed on a base material in which a first conductor layer is formed on one surface of the insulating layer and a second conductor layer is formed on the other surface of the insulating layer. And a method of forming a via hole by removing the insulating layer so as not to penetrate the second conductor layer, and focusing the first laser beam on a portion corresponding to the outer periphery of the via hole formation region in the first conductor layer. And removing the first conductor layer and the insulating layer remaining in the via hole formation region by irradiating with a second laser beam diffused from the first laser beam. It is characterized by that.

  According to the via hole forming method of the present invention, the conductor layer that requires a large beam energy is removed by focusing the first laser beam only on the outer periphery corresponding portion of the via hole forming region, so that the smaller beam energy is diffused. Since the conductor layer and the insulating layer remaining in the via hole formation region are removed by the second laser light, the condensed first laser light needs to scan only the portion corresponding to the outer periphery of the via hole formation region. Time can be shortened. In addition, productivity can be improved accordingly.

  In one embodiment of the present invention, in accordance with the irradiation with the second laser light, the dust collecting means disposed 5 mm to 15 mm above the stage on which the substrate is placed is operated and removed. A step of collecting the first conductor layer and the insulating layer;

  In the via hole forming apparatus according to the present invention, the first conductor layer is formed on a base material in which the first conductor layer is formed on one surface of the insulating layer and the second conductor layer is formed on the other surface of the insulating layer. And the insulating layer is removed so as not to penetrate the second conductor layer, and a via hole is formed in the via hole forming apparatus. A laser beam irradiation means for removing the first conductor layer and the insulating layer remaining in the via hole formation region by irradiating a second laser beam diffused from the first laser beam. And a dust collecting means for collecting the first conductor layer and the insulating layer, which are disposed 5 to 15 mm above the stage on which the substrate is placed and removed by the laser light irradiation means. When That.

  According to the via hole forming apparatus of the present invention, the same effect as the above via hole forming method can be obtained, and the via hole can be formed without leaving the removed first conductor layer or insulating layer on the substrate. Therefore, it is possible to perform the formation with high accuracy without causing the removed dust and debris to adhere to the substrate again.

  According to the present invention, the formation time of a via hole by a laser can be shortened and productivity can be improved.

It is a flowchart which shows the via hole formation processing procedure by the via hole formation method which concerns on one Embodiment of this invention. It is sectional drawing which shows the outline | summary of a structure of the via-hole formation apparatus which concerns on one Embodiment of this invention. It is a top view which shows the base-material surface at the time of formation by the via-hole formation apparatus. It is sectional drawing which shows the outline | summary of a structure of the via-hole formation apparatus. It is a top view which shows the base-material surface at the time of formation by the via-hole formation apparatus.

  Hereinafter, a via hole forming method and a via hole forming apparatus according to embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a flowchart showing a via hole formation processing procedure by a via hole formation method according to an embodiment of the present invention. 2 and 4 are sectional views showing an outline of the configuration of the via hole forming apparatus according to one embodiment of the present invention. Further, FIG. 3 and FIG. 5 are plan views showing the surface of the base material at the time of formation by this via hole forming apparatus.

  A via hole forming method by the via hole forming apparatus according to the present embodiment will be described with reference to FIG. First, the via hole forming apparatus 100 is activated, and as shown in FIG. 2, the process waits until the formation process is started (N in Step S100). After the process is started (Y in Step S100), the operation of the dust collector 20 is started. (Step S102).

  Here, the via hole forming apparatus 100 includes a stage 19 on which the processed base material 10 is placed, a laser irradiation device (not shown) that irradiates the processed base material with the laser beams L1 and L2, and the processed base material 10. And a dust collector 20 disposed above, and has a control unit (not shown) for controlling the operation of each unit.

  The processed substrate 10 includes an insulating layer 11 made of an insulating resin such as polyimide (PI) resin, and conductor layers 12 and 13 made of a conductive member such as a copper foil formed on both surfaces of the insulating layer 11. It is configured. The via hole forming apparatus 100 removes the conductor layer 12 and the insulating layer 11 on one surface of the processed substrate 10 so that the conductor layer 13 is exposed, and forms a so-called blind via hole (BVH).

  The insulating layer 11 of the processed substrate 10 is formed of, for example, a resin film having a thickness of about 12 μm. As the resin film, in addition to the above polyimide, a resin film made of polyolefin (PO), liquid crystal polymer (LCP), or the like, a resin film made of thermosetting epoxy resin (EP), or the like may be used. The conductor layers 12 and 13 are similarly formed to have a thickness of about 12 μm, and therefore the processed substrate 10 is formed of a so-called double-sided copper-clad laminate (double-sided CCL).

  The dust collector 20 includes a housing portion 21 that is open on the side facing the processed substrate 10, a duct portion 22 that communicates with the housing portion 21, a filter, a fan, a fan motor, And a drive unit (not shown) including a control device and the like. Further, on the side opposite to the opening side of the housing part 20 of the dust collector 20, a window part 23 capable of transmitting the laser beams L1 and L2 is provided. The dust collector 20 collects the conductor layer 12 and the insulating layer 13 removed from the processed substrate 10. In addition, if the dust collector 20 is too close to the processed base material 10, the processed base material 10 may come into contact with the processed base material 10 or the suction force is too strong, and if it is too far, effective dust collection is performed. Not done. Therefore, the housing part 21 of the dust collector 20 has its open end disposed at a position where the distance H from the upper surface of the stage 19 is 5 mm to 15 mm.

The laser irradiation device includes a UV-YAG laser device, a carbon dioxide laser (CO ₂ laser) device, an excimer laser device, and the like. Irradiates L2. The laser beam L1 is a focused laser beam with a large beam energy having a beam spot diameter of about 20 μm to 30 μm and an energy density distribution of a Gaussian shape. The laser beam L2 is a diffused laser beam having a beam spot diameter of about 100 μm to 120 μm and a small beam energy of 0.5 to 1.5 J / cm ² per unit area as compared with the laser beam L1.

  In the present embodiment, the beam spot diameter of the laser beam L2 is adjusted so as to be equal to or larger than the diameter of the via hole formed in the processed base material 10. In this case, for example, the diameter of the via hole (that is, the diameter of the via hole forming region where the via hole is formed) is set to 100 μm.

  When the operation of the dust collector 20 is started, as shown in FIGS. 2 and 3, the laser light L <b> 1 condensed to a level at which the conductor layer 12 can be processed at a position corresponding to the outer periphery of the via hole forming region 30 is circular in the drawing. The laser irradiation apparatus is moved so as to have a locus as indicated by the arrow of the irradiation (step S104), and the conductive layer 12 on the surface layer of the processed substrate 10 is removed so as to surround the via hole forming region.

  Since the beam energy of the laser beam L1 at this time is strong, the insulating layer 11 below the conductor layer 12 is also processed.

  When the conductor layer 12 corresponding to the outer periphery of the via hole forming region 30 is removed, as shown in FIGS. 4 and 5, the beam spot diameter is the same as or slightly larger than the diameter of the via hole forming region 30. The laser beam L2 diffused to a level at which the insulating layer 11 can be processed is irradiated to the via hole forming region 30 (step S106), and the conductor layer 12 and the insulating layer 11 remaining in the via hole forming region 30 are blown off and removed. . At this time, since the removed conductor layer 12 and insulating layer 11 are not completely dissolved, they become dust and debris. These dusts and debris are sucked from the opening into the housing portion 21 of the dust collector 20 disposed above the processed substrate 10 and collected through the duct portion 22.

  Then, it is determined whether or not the forming process is to be ended (step S108). If it is determined that the forming process is not to be ended (N in step S108), the process proceeds to step S104, and the other via hole forming regions are subsequently processed. Repeat the process. When it is determined that the process is to be ended (Y in step S108), the operation of the dust collector 20 is stopped (step S110), and the series of processes according to this flowchart is ended. Note that the formed via hole is subjected to desmear treatment, plating treatment, or the like in an apparatus or the like in the subsequent stage (not shown) to form BVH.

  As described above, according to the via hole forming method and the via hole forming apparatus 100 according to the present embodiment, the via hole can be formed by the laser beam irradiation of the laser beams L1 and L2, so that the time for forming the via hole is shortened. The productivity can be improved and the removed conductor layer 12 and insulating layer 11 are not left on the processed base material 10, so that the removed portion is prevented from reattaching to the base material and the via hole is accurately formed. Can be processed.

DESCRIPTION OF SYMBOLS 10 Processing base material 11 Insulating layer 12, 13 Conductor layer 20 Dust collector 21 Case part 22 Duct part 23 Window part 30 Via-hole formation area 100 Via-hole formation apparatus

Claims (3)

A base material having a first conductor layer formed on one surface of the insulating layer and a second conductor layer formed on the other surface of the insulating layer is provided with the first conductor layer and the insulating layer, and the second conductor. In the via hole forming method of forming a via hole by removing so as not to penetrate the layer,
Disposing a dust collecting means second laser beam to windows section transmission is provided which is spread than the first laser light and the first record laser light which is focused on the substrate,
The portion corresponding to the outer periphery of the via hole forming region in the first conductor layer is removed by irradiation with the first laser light through the window of the dust collecting means so as to form a circular locus, and the dust collecting means A process of collecting dust,
Removing the first conductor layer and insulating layer remaining in the via hole forming region by irradiating the second laser light through the window of the dust collecting means and collecting the dust by the dust collecting means; A via hole forming method characterized by comprising: 2. The via hole formation according to claim 1, wherein the dust collecting means is arranged and operated at information of 5 mm to 15 mm from a stage on which the base material is placed as the second laser light is irradiated. Method. A base material having a first conductor layer formed on one surface of the insulating layer and a second conductor layer formed on the other surface of the insulating layer is provided with the first conductor layer and the insulating layer, and the second conductor. In a via hole forming apparatus that forms a via hole by removing so as not to penetrate a layer,
The portion corresponding to the outer periphery of the via hole formation region in the first conductor layer is removed by irradiating the condensed first laser beam so as to form a circular locus, and the first remaining in the via hole formation region. Laser light irradiation means for irradiating and removing one conductor layer and insulating layer by irradiating a second laser light diffused from the first laser light;
Said first and said substrate with transparent windows portion of the second laser beam is provided is disposed 5mm~15mm upwardly from the placed stage, through that by the laser beam irradiation means and the window hole forming apparatus is characterized in that a dust collecting means for dust collection of the first conductor layer and the insulating layer Ri is removed by the irradiation of the first laser beam and said second laser beam.

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