JP2009123855A - Method of repairing defects of wiring substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of repairing defects of a wiring substrate capable of repairing a missing part of a wiring pattern to planar without a prominence and easily. <P>SOLUTION: This repairing method includes: detecting a missing part 34 of a wiring pattern 32 and a missing amount thereof; and preparing a paste in an amount corresponding to the missing amount and applying the paste to the wiring substrate through a dispenser 36 to cure the paste. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a defect repairing method for a wiring board that repairs a disconnection, a dent, or the like of a wiring pattern that easily occurs in a manufacturing process of the wiring board.

  In recent years, with the miniaturization and high performance of electronic devices, there is a demand for finer and higher density wiring on a wiring board. For this reason, in the manufacturing process of the wiring board, if it is attempted to reduce the line width and the line interval of the wiring, it is difficult to form the wiring without defects, and defects such as disconnection and dent are likely to occur.

  In view of this, a repair method has been proposed in which a wire is connected to a broken portion or the like when such a break or dent occurs (see, for example, Patent Document 1). For example, as shown in FIG. 5, after a wiring layer including the wiring pattern 52 is formed on the insulating substrate 51, when a defect such as the disconnection portion 54 is detected in the wiring pattern 52, the disconnection portion 54 The disconnection was corrected by soldering both ends of the wire 53 having the same width.

However, in the conventional repair method using such a wire 53, the corrected portion is raised by the thickness of the wire 53. Therefore, when the insulating layer 55 is stacked on the corrected wiring pattern 52, the insulating layer 55 In the case of a multilayer substrate having a thin interlayer thickness that requires a reduction in the thickness of the portion, and in particular, it is difficult to ensure insulation. Also, with this method, since the line width and line spacing of the wiring are narrow, a high degree of alignment accuracy is required, and workability is likely to deteriorate.
JP-A-5-283823

  SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem, and provides a defect repair method for a wiring board capable of easily repairing a missing portion of a wiring pattern without being raised and flat. It is in.

  A defect repair method for a wiring board according to the present invention includes a defect detection step for detecting a missing portion and a missing amount of a wiring layer of the wiring substrate, and an amount corresponding to the missing amount in the missing portion detected in the defect detecting step. A coating process for coating the conductive paste, a curing process for curing the conductive paste applied in the coating process, and an insulating layer coating process for coating an insulating layer on the wiring layer. To do.

  That is, in the manufacturing process of the wiring board, the missing portion and the missing amount of the wiring layer are detected, and an amount of conductive paste corresponding to the missing amount is applied and cured, and then the insulating layer is covered. Thereby, the missing part of the wiring layer can be repaired flat without being raised. Moreover, it can repair easily compared with the conventional repair method which connects a wire, for example to a missing part.

The defect repairing method for a wiring board according to the present invention further includes a removing step of removing a portion protruding from the wiring of the conductive paste cured in the curing step.
According to this, after apply | coating and hardening an electrically conductive paste to the missing part of a wiring layer, by removing the part which protruded from the wiring, it can repair more reliably flat.

The defect repairing method for a wiring board according to the present invention is characterized in that the application of the conductive paste in the coating step is performed by a dispenser.
According to this, the conductive paste can be easily applied to the missing portion of the wiring layer, and the workability is improved.

  According to the present invention, the missing portion of the wiring pattern can be repaired flatly and easily without rising.

  Hereinafter, although embodiment of this invention is described, this invention is not limited to these.

  FIG. 1 is a flowchart showing an outline of a defect repair method for a wiring board according to the present invention.

  A wiring layer including a wiring pattern is formed in advance on an insulating substrate, and an optical or ultrasonic imaging means is used to detect the position where the wiring is missing due to disconnection or dent and the area of the missing part. Perform (S11, S12).

  In the case of using an optical imaging means, for example, a wiring pattern is imaged by a CCD camera or the like, and this image data is compared with defect-free CAD data as an inspection standard, and a non-corresponding portion is extracted as a missing portion, In addition, the area is calculated.

  On the other hand, when an ultrasonic imaging means is used, the wiring pattern is swept with ultrasonic waves, an ultrasonic image reflected by the wiring pattern and returned as an echo is detected with a transducer, and this image data is inspected. Compared with the reference defect-free CAD data, a non-corresponding portion is extracted as a missing portion, and the area is also calculated. Next, the missing amount is calculated by multiplying the detected area of the missing portion by the thickness of the predetermined wiring pattern.

Next, a predetermined amount of conductive paste is applied to the detected missing portion by using, for example, a dispenser (S13). As the conductive paste, for example, a paste obtained by adding a binder component such as a phenolic resin and a solvent to a conductive material such as copper, silver, gold, or carbon is used. The particle size of the conductive material is sufficient to repair fine wiring (for example, 50 μm)
It is preferable that it is 1.0 micrometer or less. The amount of the conductive paste applied is preferably slightly larger than the calculated missing amount in consideration of the amount that is reduced by evaporation and the amount of the applied paste flowing in the line width direction of the wiring. According to this, by adjusting the application amount according to the detected area (missing amount) of the missing portion, it is possible to minimize the swell of the paste at the repaired missing portion. Note that nanoparticles having a particle diameter of 5 to 10 nm can be used as the conductive material. According to this, a sufficient number of ultrafine particles are welded to the missing portion, and high conductivity can be obtained.

  Subsequently, the conductive paste applied to the missing portion is heated and cured (S14). After curing, an appearance inspection is performed by an optical or ultrasonic imaging means used in the defect detection step (S11), for example (S15).

  In the appearance inspection, when a bulge exceeding the thickness of the wiring caused by excessive application of the conductive paste or a portion protruding from the line width of the wiring is detected (S16), the protruding portion is detected by, for example, blade or laser irradiation. It is preferable to cut and flatten (S17). When cutting with a blade, the excess paste is scraped off and flattened by moving the blade parallel to the wiring pattern by bringing the blade into contact with the shape of the wiring pattern so that the notch of the blade engages.

  By laminating the insulating layer on the wiring pattern (S18), the wiring substrate 1 with the defects repaired as shown in FIG. 2 is obtained. FIG. 2 is a cross-sectional view schematically showing the wiring board 1 in which the defect is repaired.

  As shown in FIG. 2, the broken portion 3 of the wiring pattern 2 can be repaired flat without being raised. Thereby, even if the insulating layer 4 is laminated on the wiring layer including the wiring pattern 3, since the repaired portion is flat, insulation can be reliably ensured. In particular, it is suitable for a wiring board having a multilayer structure that requires a reduction in thickness. In addition, the position and the amount of missing portions are detected with respect to the missing portion of the wiring by using an optical imaging means, and an amount of conductive paste corresponding to the missing amount is applied by, for example, a dispenser. Even if the positioning accuracy is not high, it can be repaired easily and efficiently.

  Next, a defect repair method for a wiring board according to the first embodiment of the present invention will be described with reference to FIGS.

(First embodiment)
FIG. 3 is a diagram schematically showing the configuration of the defect repair apparatus for a wiring board according to the present embodiment.

  The defect repairing apparatus includes a CCD camera 21 that images a wiring pattern, a defect detection unit 22 that detects a defect by comparing the imaging result and CAD data of a wiring pattern serving as a detection reference, and a detected defect location. A paste application unit 23 having a dispenser for applying paste, a curing unit 24 having a halogen lamp illumination light source for thermosetting the applied paste, and a cutting unit 25 having a blade for cutting the excess paste that has been cured. And a control unit 26 for controlling them.

  Hereinafter, a defect repair method for a wiring board using this apparatus will be described with reference to FIG. FIG. 4 is a process diagram schematically showing the defect repairing method for the wiring board according to the present embodiment.

  A single-sided copper-clad plate is prepared in advance, and the copper foil on one side is patterned by etching to form a wiring layer including a wiring pattern 32 having a width of 50 μm and a pitch of 80 μm. Then, as shown in FIG. A part of the pattern 32 is artificially disconnected.

  The wiring board 33 having this pattern disconnection is placed on the XY table 27 (see FIG. 3), and the XY table 27 is driven so that the wiring board 33 is positioned directly below the CCD camera 21. The wiring board 33 is imaged by the CCD camera 21, and the defect detection unit 22 detects the coordinate position of the disconnected portion 34 of the wiring pattern 32 by comparing the imaging result with the CAD data that is the detection reference. Further, the area of the broken portion 34 is also detected, and these data are sent to the control unit 26.

  Next, the XY table 27 on which the wiring board 33 is placed is driven based on the data of the coordinate position of the disconnection point 34 sent to the control unit 26, and moves directly below the paste application unit 23 in which the dispenser 36 is installed. Let As shown in FIG. 4B, the conductive paste 35 is applied to the broken portion 34 by the dispenser 36. The coating amount is preferably slightly larger than the amount obtained by multiplying the area of the broken portion 34 sent to the control unit 26 by the thickness 12 μm of the wiring pattern 32. The applied conductive paste 35 is prepared by mixing 85 to 95% by weight of silver particles having a particle size of 0.5 μm and a phenol resin as a binder component in an organic solvent such as propylene glycol ether, and having a viscosity of 300 Pa · s (22 ° C.).

  Thereafter, the XY table 27 (see FIG. 3) on which the wiring board 33 is placed is driven and moved directly below the curing portion 24 where the halogen lamp illumination light source is disposed, and the conductive paste is heated by the heat of the light source. 35 is heat cured.

  Next, the XY table 27 on which the wiring board 33 is placed is driven, and again moves directly under the CCD camera 21, and the CCD camera 21 images the wiring board 33. The defect detection unit 22 compares the imaging result with CAD data as a detection reference.

  When the coordinate position of the hardened paste (cutting portion) protruding from the thickness of the wiring pattern 32 as shown in FIG. 4C is detected, the wiring substrate 33 is placed based on the coordinate data. The XY table 27 is driven to move directly below the cutting portion 25 where the blade 37 having a notch corresponding to the cross section of the wiring of the wiring pattern 32 is installed, and the portion excessively covered by the blade 37 is scraped off. As a result, a wiring board 33 with a broken pattern as shown in FIG. 4D is obtained. Thereafter, an insulating layer is laminated so as to cover the wiring pattern 32.

  According to the present embodiment, the broken portion 34 of the wiring pattern 32 can be repaired flat without being raised. Moreover, compared with the conventional method of repairing by connecting, for example, a wire to the disconnection point 34, the repair can be easily performed, and the workability can be improved. In addition, by manufacturing the wiring board 33 using the repair method of the present embodiment, it is possible to reduce manufacturing defects of the wiring board 33 and improve the yield.

The wiring board 33 obtained in this embodiment was subjected to TCT (temperature cycle test) and THB (high temperature and high humidity bias test) to evaluate reliability. In TCT, the wiring board 33 is preconditioned (for 30 hours at 70 ° C. and 70% RH and then reflowed at 260 ° C. MAX for 3 times), and then a temperature cycle of −65 ° C./30 minutes to 125 ° C./30 minutes. When the resistance value after 500 cycles was measured, the resistance increase with respect to the initial resistance was 10% or less. On the other hand, in THB, after the wiring board 33 is preconditioned (for 30 hours at 30 ° C. and 70% RH and then reflowed at 260 ° C. MAX for 3 times), this wiring board is subjected to conditions of 85 ° C. and 85% RH. After applying a bias voltage of 12 V to 33 for 500 hours, the insulation resistance was measured and found to be 10 ⁸ Ω or more.

  As is apparent from the above, according to the present embodiment, the wiring board 33 having excellent reliability can be obtained.

(Other embodiments)
The embodiments of the present invention have been specifically described above, but the present invention is not limited to these embodiments, and various modifications can be made without departing from the scope of the present invention.

The figure which showed the flowchart of the defect repair method of the wiring board which concerns on this invention. Sectional drawing which shows typically the wiring board by which the defect was repaired by the method shown in FIG. The figure which shows typically the defect repair apparatus which concerns on the 1st Embodiment of this invention. Process drawing which shows typically the defect repair method using the apparatus shown in FIG. Sectional drawing which shows typically the wiring board repaired by the conventional method.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,33 ... Wiring board, 2, 32, 52 ... Wiring pattern, 3, 34, 54 ... Disconnection location, 4,55 ... Insulating layer, 5, 31, 51 ... Insulating board, 21 ... CCD camera, 22 ... Defect detection , 23 ... paste application part, 24 ... curing part, 25 ... cutting part, 26 ... control part, 27 ... XY table, 35 ... conductive paste, 36 ... dispenser, 37 ... blade, 53 ... wire.

Claims (3)

A defect detection step for detecting a missing portion of the wiring layer of the wiring board and the amount of the missing portion;
An application step of applying a conductive paste in an amount corresponding to the amount of the missing portion in the missing portion detected in the defect detecting step;
A curing step of curing the conductive paste applied in the coating step;
A defect repairing method for a wiring board, comprising: an insulating layer coating step for coating an insulating layer on the wiring layer.   The defect repairing method for a wiring board according to claim 1, further comprising a removing step of removing a portion protruding from the wiring of the conductive paste cured in the curing step.   The method for repairing a defect in a wiring board according to claim 1, wherein the application of the conductive paste in the application step is performed by a dispenser.

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