JP5499554B2 - Repair method of printed circuit board pattern - Google Patents

Description

  The present invention relates to a method for repairing a printed circuit board pattern, and more particularly, to a method for repairing a printed circuit board pattern that is suitable for a printed circuit board that has a large area and requires accurate pattern formation over the entire surface.

  In general, the density of conductive layer patterns has been increasing in recent years for printed circuit boards, and it is possible to use a line / space rule that has been reduced to, for example, several tens of micrometers / several tens of micrometers. One application of such a fine rule printed circuit board is a radiation detection panel. The radiation detection panel is a radiation detection device body included in the radiation detection apparatus. For example, the radiation detection panel has a configuration in which a plurality of cells of an anode electrode and a cathode electrode are provided on a printed circuit board in a two-dimensional arrangement by a pattern forming technique (for example, the following patents) Reference 1). The high-resolution radiation incident position can be specified by arranging the cells at high density.

  A radiation detection apparatus is required to have a high resolution and cope with an increase in area (for example, 30 cm square) of a detection surface. Therefore, the radiation detection panel needs to be a printed circuit board having a large area and an accurate pattern formed over the entire surface. This is because, when there is a cell having a pattern in which accuracy is not maintained even in one place in a large area, unnecessary discharge is likely to occur between the anode and cathode electrodes. Such a discharge loses the function of the intended radiation detection panel.

  Therefore, in applications such as radiation detection panels, the required level of pattern formation accuracy is higher than in the case of general wiring boards. Moreover, it is necessary to be accurate over a relatively large area, and there is a possibility that the required quality will not be achieved in the manufacture according to the same specification as that of a general wiring board.

  Therefore, in such a case, following the pattern formation by the normal photolithography process, a process of correcting (repairing) the pattern formed with the accuracy of the position (particularly the edge position) in accordance with the layout design position is necessary. It becomes. For example, Patent Document 2 below discloses a pattern repair device. In this correction process, in addition to correcting the pattern accurately in accordance with the layout design position, it is also important to surely collect the fine peeling pieces so that they do not remain on the substrate or reattach. There is no mention of such matters in this document.

JP 2002-90465 A Japanese Utility Model Publication No. 4-40566

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for repairing a printed circuit board pattern, which has high repair position accuracy and can improve the recovery performance of a peeled piece.

In order to solve the above-described problem, a method for repairing a printed circuit board pattern, which is one embodiment of the present invention, captures an image of a surface of a printed circuit board having a patterned conductive foil on the surface, and the image obtained by the imaging. Is compared with the layout design pattern information stored in advance, and the pattern edge to be corrected is specified, and the specified pattern edge is brought close to the pattern based on the layout design pattern information. A process of separating the conductive foil to obtain a peeled piece by pressing the blade edge against the conductive foil and laying it down, and each time the peeled piece is generated, air is blown onto the area where the blade edge is pressed on the printed circuit board. It said release strip is irradiated with ultrasonic waves released from the printed circuit board without performing, in addition with the region The and a step of recovering said release strip by suction in negative pressure.

  That is, first, the surface of the printed circuit board having the patterned conductive foil on the surface is imaged with a camera, and the image obtained by imaging is compared with the layout design pattern information stored in advance, so that the pattern edge to be corrected Is identified. Thereby, the pattern edge to be corrected can be accurately grasped without omission.

  Next, the blade edge is pressed against the conductive foil of the printed circuit board so that the specified pattern edge is close to the pattern based on the layout design pattern information, and the strip is separated from the conductive foil to obtain a peeling piece. According to the correction using such a blade edge, even when the conductive foil is made of resin, for example, damage (side effects) to the resin can be minimized.

  Then, ultrasonic waves are applied to the area on the printed board where the blade edge is pressed to release the peeled piece from the printed board, and in addition, the peeled piece is collected by sucking in the vicinity of the area with negative pressure. According to such recovery of the peeled piece, it is possible to reliably recover the peeled piece without remaining residue or reattachment to the substrate. Further, it is easy to make the apparatus non-contact with the printed circuit board, and there are almost no side effects on the printed circuit board. As described above, it is possible to provide a method capable of improving the repair position accuracy and improving the recovery performance of the peeled pieces.

  According to the present invention, it is possible to provide a method for repairing a printed circuit board pattern, which has high repair position accuracy and can improve the recovery performance of a peeled piece.

The top view which shows the structure of the printed circuit board for radiation detection panels as an example of the printed circuit board which can apply the repair method of the printed circuit board pattern which is embodiment of this invention. The mode figure which shows the process of specifying the pattern edge which should be corrected among the repair methods of the printed circuit board pattern which is embodiment of this invention. Explanatory drawing about determination of the pattern edge which should be corrected. FIG. 4 is an explanatory diagram for determining a pattern edge (when bridged) to be corrected, different from that shown in FIG. 3. The mode figure which shows the process of isolate | separating from a conductive foil and obtaining a peeling piece among the repair methods of a printed circuit board pattern which is embodiment of this invention. Explanatory drawing of the effect which puts a correction needle to sleep. The aspect figure which shows the process of collect | recovering peeling pieces among the repair methods of the printed circuit board pattern which is embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. First, a printed circuit board to which a printed circuit board pattern repair method according to an embodiment of the present invention can be applied will be described with reference to FIG. FIG. 1 is a top view showing a configuration of a printed circuit board for a radiation detection panel which is an example of an object to which such a method can be applied. As shown in FIG. 1, the printed circuit board 1 for radiation detection panel includes an insulating plate 10, a surface conductive foil pattern (cathode electrode) 11, a surface conductor pattern (anode electrode) 12, and a back surface conductive foil pattern (anode wiring pattern). 13

  The surface conductor pattern (anode electrode) 12 is a substantially circular pattern that is exposed on one side of the insulating plate 10 and arranged in a grid. The diameter of each is, for example, 60 μm, and is arranged vertically and horizontally, for example, at a pitch of 400 μm. There are about 600,000, for example, in an area of 30 cm × 30 cm as a whole.

  The surface conductive foil pattern (cathode electrode) 11 is a layer formed in a pattern which is exposed on one side of the insulating plate 10 and is spaced apart from each surface conductor pattern 12 at substantially equal intervals and surrounds each surface conductor pattern 12. is there. The surrounding diameter is, for example, 250 μm, and is a continuous pattern in the vertical direction of each row in the illustration of FIG.

  The insulating plate 10 has a surface conductive foil pattern (cathode electrode) 11 on its surface, and exposes a surface conductor pattern (anode electrode) 12, and a back surface conductive foil pattern (anode wiring pattern) 13 on its back surface. The thickness is, for example, 0.07 mm to 0.1 mm. The material is polyimide, for example.

  Each surface conductor pattern (anode electrode) 12 is a conductive via formed through the insulating plate 10, and is electrically connected to the conductive foil pattern (anode wiring pattern) 13 on the back side of the insulating plate 10. Connected. The via (anode electrode 12) is formed by, for example, metal (copper) plating. Each via is electrically connected by a backside conductive foil pattern (anode wiring pattern) 13 so that those in the horizontal direction in FIG. 1 are the same electrical node. Each back surface conductive foil pattern (anode wiring pattern) 13 has a width of, for example, 300 μm.

  The usage of the printed circuit board (for radiation detection panel) 1 having the above-described configuration will be briefly described below. A voltage is applied between the anode electrode 12 and the cathode electrode 11, and in this state, radiation is incident on the atmosphere. Thus, when gas particle excitation occurs, a leakage current flows between the anode electrode 12 and the cathode electrode 11. The radiation incident position can be detected based on the positions of the anode electrode 11 and the cathode electrode 11 where the leakage current is generated.

  The applied voltage is 600 V, for example, but the higher the voltage, the greater the leakage current and the easier it is to detect, so that the radiation detection sensitivity can be improved. However, if the applied voltage is increased too much, the gap between the anode electrode 12 and the cathode electrode 11 is discharged, making it useless as a radiation detection panel. As a radiation detection panel, it is required that an accurate pattern is formed for any set of anode electrode 12 and cathode electrode 11. If there is a pattern whose accuracy is not maintained even at one place, unnecessary discharge occurs between the anode electrode 12 and the cathode electrode 11.

  Next, a method for repairing a printed circuit board pattern, which is an embodiment of the present invention, will be described below. First, with reference to FIG. 2, the process of specifying the pattern edge to be corrected will be described. As described with reference to FIG. 1, in applications such as radiation detection panels as printed boards, the required level of pattern formation accuracy is higher than in the case of general wiring boards. In addition, it is necessary to be accurate over a relatively large area, and in the manufacture based on the same specifications as those of a general wiring board, a state that does not reach the required quality is likely to occur. Hereinafter, an example of the printed circuit board for the radiation detection panel will be described. However, in the sense of a method for repairing a printed circuit board pattern, this method cannot be applied to a general wiring board.

  As shown in FIG. 2, the upper surface of the printed board 1 is imaged by a camera (for example, a CCD camera) 21. Image information obtained by imaging is sent to a comparison unit 22b in the information processing unit 22. The information processing unit 22 includes a layout design pattern information storage unit 22a in which layout design pattern information of the printed circuit board 1 is stored. In the comparison unit 22b, image information sent from the camera 21 is compared with information stored in the layout design pattern information storage unit 22a, and a pattern edge to be corrected necessary on the printed circuit board 1 is specified by this comparison. . The position information obtained by this specification is stored in the corrected position information storage unit 22c. With the above configuration, the pattern edge to be corrected can be accurately grasped without omission.

  FIG. 3 is an explanatory diagram for determining a pattern edge to be corrected. In FIG. 3, the reference numerals used in FIG. 1 are used to indicate the same thing. As shown in FIG. 3, when imaging the cathode electrode 11 around the anode electrode 12, the difference in position between the designed edge and the actual edge of the cathode electrode 11 is shown for all the anode electrodes 12. Detect every moment while changing the imaging position. If the difference in edge position (indicated by an arrow in the figure) is equal to or greater than a predetermined threshold, the edge position is determined as a pattern edge to be corrected, and the position is stored. For example, when there is an edge difference as shown by the left arrow in FIG. 3, this is determined as an edge to be corrected, and when the edge difference is about the right arrow, it is not determined as an edge to be corrected.

  Note that the major factor that causes the actual pattern to be formed differently from the layout design pattern is that dust or other foreign matters are formed on the optical mask or between the optical mask and the resist during exposure in the photolithography process used for pattern formation. This is thought to be due to adhesion and exposure of the resist due to this foreign matter. Since the fineness of the pattern of the printed circuit board 1 is a line / space of several tens of μm, even a very small foreign substance having this dimension level affects the accuracy of the pattern to be formed. If excessive, the patterns may be formed by bridging.

  FIG. 4 is an explanatory diagram regarding determination of a pattern edge to be corrected, which is different from that shown in FIG. Also in FIG. 4, the same reference numerals used in FIG. 1 are used to indicate the same thing. As shown in FIG. 4, when an image is taken between the cathode electrode 11 and the adjacent cathode electrode 11, in particular, a case where they are bridged is detected and determined, and this is corrected. This is because a high voltage is not applied between the cathode electrode 11 and the adjacent cathode electrode 11, so that even if the edge position deviates from the design position, it is acceptable as long as it does not reach the bridge.

  More specifically, the difference in position between the designed edge and the actual edge between the cathode electrodes 11 is detected momentarily while changing the imaging position. If the cathode electrodes 11 are bridged, the edge position is determined as the pattern edge to be corrected, and the position is stored.

  Next, FIG. 5 is an aspect view showing a process of separating the conductive foil and obtaining a peeled piece in the printed circuit board pattern repair method according to the embodiment of the present invention. 5A is a view from the top corresponding to FIG. 3, and FIG. 5B is a view showing a cross-section in the direction of the arrow at the position A-Aa in FIG. 5A. As shown in FIG. 5, with respect to the specified pattern edge to be corrected, the cutting edge of the correction needle 31 is pressed so as to be corrected to the pattern based on the layout design pattern information. In some cases, the blade edge position is shifted little by little and the blade edge of the correction needle 31 is pressed a plurality of times, whereby the excess portion of the pattern 11 is separated from the remaining normal pattern 11 as a peeling piece.

  The correction needle 31 has, for example, a rectangular cross-sectional shape at its tip, and its size is, for example, 5 μm × 30 μm. As it goes to the base, it gradually becomes thicker and the cross-section becomes a circle, and it is made of, for example, stainless steel (others can use titanium steel) to ensure rigidity. The force for pressing the correction needle 31 against the pattern 11 is determined by adjusting an appropriate force for cutting the pattern 11, for example, within a range of 3 gf to 20 gf. Such correction of the pattern 11 by the correction needle 31 can minimize damage to the resin even when the insulating plate 10 under the pattern 11 is a resin such as polyimide. Such advantages cannot be obtained by laser processing that generates high temperatures.

  FIG. 6 is an explanatory diagram of the effect of putting the correction needle 31 to sleep. As shown in the figure, the correction needle 31 has its root side on the side of the desired pattern 11 when the cutting edge of the correction needle 31 is pressed onto the pattern 11 so that the peeling piece 11a can be easily peeled off from the insulating plate 10. It is preferable to lie down a little. In this way, the peeling piece 11a can be reliably detached from the insulating plate 10. The degree of laying is determined by adjusting within a range of about 20 degrees or less so as to promote the separation of the peeling piece 11a from the insulating plate 10.

  The processes shown in FIGS. 5 and 6 can be performed by directly displaying the information stored in the correction position information storage unit 22c on a monitor, for example, and manipulating the correction needle 31 directly with a human hand while watching the information. However, mechanization is also possible. That is, first, the position for pressing the correction needle 31 is set (using information stored in the correction position information storage unit 22c), and secondly, the correction needle 31 is pressed onto the pattern 11 with a predetermined force and further corrected. The needle 31 is laid at a predetermined angle. The description of FIGS. 5 and 6 is the same in the case of correcting the pattern 11 at the location shown in FIG.

  Next, FIG. 7 is an aspect view showing a process of collecting the peeled pieces in the printed circuit board pattern repair method according to the embodiment of the present invention. In FIG. 7, the same reference numerals are given to the same components as those appearing in the already described drawings.

  In repairing the printed circuit board pattern, it is very important to remove the peeling piece 11a from the printed circuit board 1 without leakage. For this reason, as a well-known method, there is a method in which air is blown onto the printed circuit board 1. In this case, a very small peeling piece 11a flies in the air and contaminates the atmosphere. There is a high possibility that the peeling piece 11a will adhere again on the printed circuit board 1 exposed to such contaminated air. Further, the peeling piece 11a may remain attached on the printed circuit board 1 depending on the angle of air blowing.

  Such a drawback is eliminated by the method shown in FIG. That is, first, an ultrasonic wave 410 is irradiated in the vicinity of the peeling piece 11 a by the ultrasonic wave generator 41. The peeling piece 11a is released from the insulating plate 10 very reliably by the energy of the ultrasonic wave 410. Then, a negative pressure is generated by the suction unit 42, and an air flow 420 is generated from the suction port 42a into the suction unit 42, thereby sucking and collecting the peeling piece 11a. If such collection is performed every time the peeling piece 11a is generated, the atmosphere will not become a contamination source. Therefore, it is possible to reliably collect the peeled pieces without the remaining sticking or reattachment of the peeled pieces 11a. In addition, it is easy for the collection device to be in non-contact with the printed circuit board 1, and there are almost no side effects on the printed circuit board 1.

  In order to perform only the process shown in FIG. 7, “ultrasonic cleaner UVU-F type (manufactured by Shinko Co., Ltd.)” can be used as an existing apparatus. Preferably, if the same functional unit is provided so as to be incorporated in an apparatus for performing the steps shown in FIGS. 5 and 6, the repair efficiency is improved.

  DESCRIPTION OF SYMBOLS 1 ... Printed circuit board (for radiation detection panels), 10 ... Insulating plate, 11 ... Surface conductive foil pattern (cathode electrode), 11a ... Stripping piece, 12 ... Surface conductor pattern (anode electrode), 13 ... Back surface conductive foil pattern ( Anode wiring pattern), 21 ... camera, 22 ... information processing unit, 22a ... layout design pattern storage unit, 22b ... comparison unit, 22c ... correction position information storage unit, 31 ... correction needle, 41 ... ultrasonic wave generation unit, 42 ... Suction part, 42a ... suction port, 410 ... ultrasonic wave, 420 ... air flow.

Claims (1)

A process of identifying a pattern edge to be corrected by imaging a surface of a printed circuit board having a patterned conductive foil on the surface with a camera and comparing the image obtained by the imaging with layout design pattern information stored in advance. When,
A step of separating the conductive foil from the conductive foil to obtain a peeled piece by pressing the blade edge against the conductive foil of the printed circuit board so as to bring the identified pattern edge closer to the pattern based on the layout design pattern information. When,
Each time the peel piece is generated, the area on the printed circuit board pressed against the blade edge is irradiated with ultrasonic waves without air blowing to release the peel piece from the printed circuit board, and in addition, the area near the area is shaded. A method of repairing a printed circuit board pattern, comprising: a step of collecting the peeled piece by inhalation under pressure.

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