JP5403177B1 - Method for manufacturing printed wiring board - Google Patents

Abstract

In an adhesive filled in a joint between an individual substrate and a discarded frame portion, voids due to so-called air biting are likely to occur, and the voids burst due to thermal expansion of air forming the voids in the adhesive. Or a crack occurs in the cured adhesive starting from the void, which causes a problem that the adhesive effect of the adhesive cannot be sufficiently obtained and the fixing of the individual substrate to the discarded frame portion becomes insufficient. .
SOLUTION: A slit-shaped adhesive portion is formed when a good individual substrate is fitted to a discarded frame portion by a convex portion provided on a good individual substrate and a concave portion provided on a discarded frame portion of a plurality of collecting substrates. Then, an adhesive is filled into the slit-like adhesive portion by ink jet and cured. The average particle diameter of the adhesive discharged by inkjet is in the range of 20% to 80% with respect to the width of the slit-like adhesive part.
[Selection] Figure 1

Description

  The present invention relates to a method for manufacturing a printed wiring board used in various electronic devices such as personal computers, mobile communication devices, video cameras, and digital cameras.

  In recent years, electronic components have been increasingly miniaturized, highly integrated, increased in speed, and increased in number of pins due to higher functionality and higher density of electronic devices. Along with this, printed wiring boards have also been increased in density, circuit patterns have become thinner, and mounting lands have a smaller diameter. Similarly, in the formation of a solder resist for covering a circuit pattern, a high degree of matching accuracy has been required in order to align with a circuit pattern or mounting land whose density has been increased.

  For this reason, in circuit pattern formation, even slight defects and copper foil residue that had not been a problem in the past have led to defects such as disconnection and short circuit. Due to the deviation, it has become necessary to judge a defect.

  On the other hand, as a form at the time of mounting a component of a printed wiring board, a plurality of substrates having a group of a plurality of individual substrates as a unit has been generalized due to downsizing of electronic devices. For example, taking a mobile phone as an example, the printed wiring board used for one mobile phone is typically about 120 mm × 50 mm in size, but is provided around the board by using a two-piece board. When the frame portion is also included, it can be 150 mm × 140 mm, and by using a three-piece substrate, it can be 150 mm × 200 mm.

  This is because when a substrate is flowed through a series of processes such as solder paste printing, component mounting, and reflow soldering at the time of component mounting, it is easier to handle the substrate having a certain size and production efficiency is better.

  However, as a printed wiring board manufacturer, in the case of multiple printed circuit boards, even if only one of the multiple individual boards becomes defective, the entire multiple printed circuit board is discarded as defective. Usually it must be. This is because if a product including a defective individual board is put into the component mounting process, the component is mounted on the defective individual board. This is because the loss increases due to the processing.

  In view of this, in recent years, a correction method in which a defective individual substrate is removed from a plurality of substrates including a defective individual substrate, and a separately prepared non-defective individual substrate is fitted into the portion has become widespread. . According to this method, even if a defective individual substrate is included in a plurality of substrates, other good individual substrates can be used as good products without being discarded, and the disposal cost can be reduced. Can do.

  Hereinafter, a conventional method for manufacturing a printed wiring board according to the correction method will be described with reference to the drawings.

  In general, a printed wiring board is formed with a circuit pattern in a panel state of, for example, 500 mm × 330 mm in a state where a plurality of substrates are further assembled, and thereafter, a solder resist for covering the circuit pattern is formed. Thereafter, printing such as marking ink or gold plating on the circuit is performed as necessary.

  Thereafter, a plurality of substrates are processed by punching with a die or cutting with a router bit as shown in FIG. In FIG. 5 (a), each of the two printed wiring boards 1a and 1b configured as a plurality of printed circuit boards has individual substrates 2a, 2b and 2c, 2d. Further, the printed wiring boards 1a and 1b respectively have discard frame portions 3a and 3b for connecting the individual substrates 2a and 2b, 2c and 2d, and further reinforcing the periphery of these. Each of the individual substrates 2a to 2d has a connecting limb 4 for connecting to the throwing frame portions 3a and 3b. In FIG. 5A, the printed wiring boards 1a and 1b have two connecting limbs 4 on the long side and one on each short side among the four sides of the individual substrates 2a to 2d. .

  With respect to the printed wiring board 1a having the above configuration, a procedure for exchanging the defective portion with a non-defective product in the printed wiring board including the defective individual substrate will be described with reference to FIGS. 5 (a) to 5 (c).

  Here, in the printed wiring board 1a composed of two individual substrates 2a and 2b, one of the individual substrates 2a is a non-defective product (OK1) and the other individual substrate 2b is a defective product (NG1). An example in which a non-defective individual substrate 2b (NG1) is replaced with a non-defective product will be described. In this case, in order to replace the defective individual substrate 2b (NG1) with a non-defective product, it is necessary to prepare a separate non-defective substrate. For this purpose, it is convenient to cut out a good individual substrate 2d (OK2) from the printed wiring board 1b including another defective individual substrate 2c (NG2) as shown in FIG. 5B. This is because it is not necessary to correct other defective products until the printed wiring board, which is composed of all good individual substrates, is disassembled.

  FIG. 5B shows a state in which the defective individual board 2b (NG1) is removed from the printed wiring board 1a, and a non-defective individual board 2d (OK2) to be fitted in this position is cut out from the printed wiring board 1b. Indicates the state. After removing the defective individual substrate 2b (NG1) and preparing the non-defective individual substrate 2d (OK2) in this way, the non-defective individual substrate 2d (OK2) is inserted into the discard frame portion 3a. As shown in FIG. 5C, the corrected printed wiring board 1a is obtained.

  If FIG. 5A is compared with FIG. 5C, the effect of this correction can be understood at a glance. In FIG. 5 (a), both sheets of the printed wiring boards 1a and 1b include defective individual substrates, so that both of them normally have to be discarded. On the other hand, in FIG. 5 (c), the corrected printed wiring board 1a is composed of only non-defective individual substrates, and therefore can be used as non-defective products.

  Thereby, a manufacturing yield can be improved and disposal loss, such as material cost, labor cost, and equipment cost, can be reduced.

  In FIG. 5C, several methods have been proposed as a fixing method when the non-defective individual substrate 2d (OK2) is fitted into the discard frame portion 3a. As a simple method, there is a method in which the individual substrate 2d is thrown away into the frame portion 3a at the fitting portion. However, according to this method, the positional deviation of the individual substrate 2d with respect to the discard frame portion 3a due to the cutting position accuracy of the cutting process of the individual substrate 2d and the discard frame portion 3a and the fitting portion at the time of press-fitting becomes a problem. In the component mounting process, the positioning is usually performed by reading the recognition mark provided on the discard frame 3a, and the component is mounted at a predetermined position with respect to the individual substrate 2d with reference to the coordinates. This is because a mounting failure occurs during component mounting.

  Therefore, as an alternative method, as shown in FIG. 6, a method of bonding the fitting portion with an adhesive after positioning the individual substrate 2d with respect to the discard frame portion 3a has been used. In this method, the adhesive 7 is filled by the dispenser 6 at the joint between the individual substrate 2 and the discard frame portion 3. In order to prevent the adhesive 7 from spreading on the back side of the printed wiring board, a method of covering the fitting portion of the individual substrate 2 and the discard frame portion 3 with the fixing tape 5 from the back side may be used.

  Further, a thermosetting resin is used as the adhesive 7 and is cured by heating in a heating furnace after filling a predetermined portion. Therefore, heat-resistant tape such as Kapton tape is used as the fixing tape 5 and is peeled off after the adhesive 7 is cured.

  As prior art document information related to the invention of this application, for example, Patent Documents 1 and 2 are known.

Japanese Patent Laid-Open No. 01-48489 JP 2000-252605 A

  However, in the conventional method for manufacturing a printed wiring board, the following has occurred as a problem. That is, the density of printed wiring boards has been increased, and the accuracy required as the alignment accuracy of the individual board with respect to the above-mentioned discard frame has become high, while the seam between the individual board and the discard frame has been increased. The filling space for filling the provided adhesive is also becoming smaller. Also, the adhesive is pushed out from the tip of the dispenser in a columnar shape without interruption, and filling is performed in a space that has become smaller by moving the position of the dispenser.

  As a result, as shown in FIG. 6, voids 8 due to so-called air biting are likely to occur in the adhesive filled in the joint between the individual substrate and the discarded frame portion. The generation of the void 8 causes the following problems. That is, due to the presence of the void 8, the adhesion area of the individual substrate or the discard frame portion with the adhesive is reduced, so that the adhesive effect of the adhesive cannot be sufficiently obtained, and fixing of the individual substrate to the discard frame portion is not possible. The problem of becoming sufficient has arisen.

  Further, during heating for curing the adhesive, the air forming the void 8 thermally expands in the adhesive, so that the void 8 is ruptured or cracked in the cured adhesive starting from the void 8. Can happen. Also by this, the adhesive effect of the adhesive cannot be sufficiently obtained, and there arises a problem that the fixing of the individual substrate to the discarded frame portion becomes insufficient.

  As a result, the alignment accuracy of the individual substrate with respect to the discard frame portion deteriorates, and it becomes necessary to discard the defective substrate again as a defect in the inspection after correction. Moreover, even if a predetermined accuracy is obtained at the time of inspection as a printed wiring board, there is a concern that the above-mentioned positional accuracy deteriorates due to the effect of heating at the time of subsequent component mounting, and that component mounting defects may occur. Became.

  The present invention solves the above-described conventional problems, and can provide adhesion that can sufficiently secure the fixing strength of the individual substrate with respect to the discarded frame portion, and does not deteriorate the alignment accuracy of the individual substrate with respect to the discarded frame portion. It aims at providing the manufacturing method of a printed wiring board.

  In order to achieve this object, the printed wiring board manufacturing method of the present invention is a defective individual board in a plurality of individual boards made up of a plurality of individual boards connected to a discarded frame part via connecting limbs. A defective product removing step of removing the defective individual substrate from a plurality of substrates including a non-defective product, a non-defective product preparing step of separately preparing a non-defective individual substrate, and removing the defective individual substrate of the multi-substrate A non-defective product placement step of placing the non-defective product individual substrate at a position, and a non-defective product bonding step of bonding the non-defective product individual substrate to the multiple substrate obtained by removing the defective individual substrate. And a step of processing the defective individual substrate into a shape surrounding the base of the connecting limb portion and having a recess on the side of the discard frame, wherein the non-defective individual substrate is the non-defective substrate of the plurality of substrates. Excluding non-defective individual substrates When the non-defective individual substrate is disposed at the position, the convex portion that fits into the concave portion of the discard frame portion and forms a slit-like adhesive portion between the concave portion of the discard frame portion, In the non-defective product arranging step, the non-defective product individual substrate is aligned with the plurality of substrates obtained by removing the defective individual substrate fixed through the first adhesive sheet previously attached on the plate. It is arranged and fixed on the first pressure-sensitive adhesive sheet, and the non-defective bonding step is a method for producing a printed wiring board, wherein the slit-like bonding portion is filled with an adhesive by ink jet and cured. Is.

  With this configuration, the adhesive is filled into the slit-like adhesive portion formed between the convex portion of the individual substrate and the concave portion of the discard frame portion in the form of droplets discharged from the head nozzle by inkjet. The Therefore, there is always an air escape area around the droplet-like adhesive particles, which has the effect of preventing the generation of voids due to so-called air biting.

  In the printed wiring board manufacturing method of the present invention, the average particle diameter of the adhesive ejected by ink jet in the non-defective product adhesion step is in the range of 20% to 80% with respect to the width of the slit-shaped adhesive portion. There is. With this configuration, the adhesive can be efficiently filled in the slit-like adhesive portion without generating voids due to air biting or protruding the adhesive from the adhesive portion.

  In the printed wiring board manufacturing method of the present invention, the first pressure-sensitive adhesive sheet is further bonded onto the plate via the second pressure-sensitive adhesive sheet. The adhesive strength between the first adhesive sheet and the second adhesive sheet is greater than the adhesive strength between the first adhesive sheet and the second adhesive sheet, and the adhesive strength between the second adhesive sheet and the plate is It is larger than the adhesive strength between the second adhesive sheet. With this configuration, even when warping occurs on a plurality of substrates or non-defective individual substrates, the first adhesive sheet is peeled off from the second adhesive sheet so that the first adhesive sheet can be separated into a plurality of substrates and non-defective substrates individually. Following the substrate, as a result, the adhesive filled in the slit-like adhesive portion is sealed by ink jet, and the adhesive can be prevented from spreading to the back side of the printed wiring board.

  Moreover, the manufacturing method of the printed wiring board of this invention is that an adhesive agent is an ultraviolet curable type. With this configuration, the adhesive can be cured without being heated. Therefore, when the adhesive is a thermosetting resin, a plurality of substrates obtained by removing defective individual substrates and non-defective individual substrates that are generated during heating are removed. It is possible to prevent positional deviation due to warpage or dimensional change.

  According to the method for manufacturing a printed wiring board of the present invention, even in a printed wiring board that requires high-density wiring, it is possible to obtain adhesion that can sufficiently secure the fixing strength of the individual substrate with respect to the discarded frame portion. It is possible to provide a method for manufacturing a printed wiring board in which the substrate alignment accuracy does not deteriorate.

The top view which shows the manufacturing method of the printed wiring board in embodiment of this invention The top view which shows the manufacturing method of the printed wiring board in embodiment of this invention Sectional drawing which shows the manufacturing method of the printed wiring board in embodiment of this invention Sectional drawing which shows the manufacturing method of the printed wiring board in embodiment of this invention Plan view showing a conventional printed wiring board manufacturing method Sectional drawing which shows the manufacturing method of the conventional printed wiring board

  Embodiments of the present invention will be described below with reference to the drawings.

  1 and 2 are plan views showing a method for manufacturing a printed wiring board according to an embodiment of the present invention. FIG. 3 is a cross-sectional view showing a method for manufacturing a printed wiring board according to the embodiment of the present invention.

  The printed wiring board according to the embodiment of the present invention is a plurality of printed circuit boards with an aggregate of a plurality of individual substrates as a unit. In FIG. 1 (a), printed wiring boards 11a and 11b are two-piece boards composed of two individual boards, and are constituted by individual boards 12a and 12b and 12c and 12d, respectively.

  Further, the printed wiring boards 11a and 11b respectively have discard frame portions 13a and 13b for connecting the individual substrates 12a and 12b, 12c and 12d, and for reinforcing the periphery thereof. Each of the individual substrates 12a to 12d has a connecting limb portion 14 for coupling to the discard frame portions 13a and 13b. In FIG. 1A, the printed wiring boards 11a and 11b have two connecting limbs 14 on the long side and one on each short side among the four sides of the individual boards 12a to 12d. .

  As the size of the individual substrates 12a to 12d, in the case of a substrate for a mobile phone, a typical value of about 120 mm × 50 mm can be considered. In this case, the size of the printed wiring boards 11a and 11b, which are two-sided boards, is about 150 mm × 140 mm when including the discarded frame portions 13a and 13b provided around the board.

  In general, in the manufacturing process of a printed wiring board, the printed wiring board is processed and processed in each process in a panel state of, for example, 500 mm × 330 mm in a state where a plurality of substrates are further assembled. Then, a circuit pattern is formed on the outermost layer portion and a solder resist is formed to cover the circuit pattern. Thereafter, printing such as marking ink or gold plating on the circuit is performed as necessary. Thereafter, a plurality of substrates are processed by punching with a die or cutting with a router bit as shown in FIG.

  The printed wiring board is subjected to circuit pattern continuity inspection such as disconnection and short circuit and solder resist peeling, appearance inspection such as adhesion of foreign matter, scratches, and dents as quality confirmation after processing into the above-mentioned multiple substrates. If a defect is found here, the printed wiring board must be disposed of without being shipped. In the case of multiple substrates, even if only one of the plurality of individual substrates is defective, it is usually necessary to dispose of the entire multiple substrate as defective. In FIG. 1A, even if only the individual board 12b is defective among the individual boards 12a and 12b of the printed wiring board 11a which is a two-piece board, the entire printed wiring board 11a must be disposed of as it is. Don't be.

  Therefore, in the embodiment of the present invention, the defective individual substrate 12b is replaced with a non-defective product in the printed wiring board 11a by the following procedure.

  In order to replace the defective individual substrate 12b (NG1) with a non-defective product, it is necessary to prepare a separate non-defective substrate. For this purpose, as shown in FIG. 1B, a non-defective individual substrate 12d (OK2) is cut out from a printed wiring board 11b including another defective individual substrate 12c (NG2).

  FIG. 1B shows a state in which the defective individual board 12b (NG1) is removed from the printed wiring board 11a, and a non-defective individual board 12d (OK2) to be fitted in this position is cut out from the printed wiring board 11b. Indicates the state.

  As shown in FIG. 1B, when removing the defective individual board 12b (NG1) from the printed wiring board 11a, the root of the connecting limb 14 connected to the defective individual board 12b (NG1) is used. It is processed into a shape having a concave portion on the side of the discarded frame portion 13a in a surrounding shape.

  Further, when cutting out a non-defective individual substrate 12d (OK2) from a printed wiring board 11b including another defective individual substrate 12c (NG2), it fits into a recess processed into a discarded frame portion 13a in the printed wiring board 11a. In order to obtain a matching shape, it is processed into a shape having a convex portion in a shape surrounding the root of the connecting limb portion 14 connected to the non-defective individual substrate 12d (OK2). By doing this, when the good individual substrate 12d (OK2) is discarded and adhered to the frame portion 13a, the adhesion area around the base of the connecting limb portion 14 can be increased, and the good individual substrate 12d (OK2) can be removed. This is because it can be firmly fixed to the discard frame 13a.

  Further, as will be described later, a slit for filling an adhesive when a convex portion processed into a good individual substrate 12d (OK2) is fitted into a concave portion processed into the discarded frame portion 13a of the printed wiring board 11a. The size of the concave portion and the convex portion is processed with a predetermined dimension so that the shaped adhesive portion is formed with a predetermined width.

  Next, as shown in FIG. 1C, the prepared good individual substrate 12d (OK2) is fitted into the printed wiring board 11a from which the defective individual substrate 12b (NG1) has been removed. Here, it is necessary to fit the individual substrate 12d (OK2) with respect to the printed wiring board 11a after accurately aligning it with a predetermined position. This is because the mounting parts mounted on the printed wiring board are reduced in size and the mounting lands of the printed wiring board are also increased in density, and high accuracy is required as positioning accuracy during mounting. As a mounting method in the component mounting process, for example, a printed wiring board is fixed through a guide pin (not shown) provided at four corners of the discard frame portion 13a through a guide pin, and further applied to the discard frame portion 13a. The alignment mark is recognized by the camera, and the mounted component is mounted at a predetermined position with reference to the coordinates calculated from the alignment mark.

  In order to accurately align the non-defective individual substrate 12d (OK2) to the predetermined position with respect to the printed wiring board 11a, the non-defective frame 13a of the printed wiring board 11a and the non-defective individual substrate 12d (OK2) are provided. A positioning mark (not shown) is recognized by an imaging means such as a camera, and positioning is performed. That is, by recognizing the alignment mark given to the discarded frame portion 13a of the printed wiring board 11a by the camera, the coordinates on the printed wiring board 11a are set based on this. Next, the position of the good individual substrate 12d (OK2) is recognized by recognizing the alignment mark given to the good individual substrate 12d (OK2) with the camera, and then the coordinates of the printed wiring board 11a set earlier are set. Move to a predetermined position above.

  The printed wiring board 11a is affixed and fixed in advance on the first adhesive sheet affixed on the plate. The non-defective individual substrate 12d (OK2) is fixed by a suction unit or the like attached to a movable drive unit, and after being recognized by the camera in that state, the drive unit is driven to a predetermined position while being fixed to the suction unit. Move by. Since the defective first substrate 12b (NG1) of the printed wiring board 11a is removed, the first adhesive sheet attached to the bottom is exposed, so the non-defective individual substrate 12d (OK2) moved to a predetermined position is exposed. ) Can also be fixed by sticking to the first adhesive sheet in the same manner as the printed wiring board 11a.

  The alignment mark given to the discarded frame part 13a of the printed wiring board 11a and the good individual substrate 12d (OK2) may be given as a dedicated mark. However, the parts originally provided on the printed wiring board are Lands for mounting and alignment marks used in the mounting process can also be used.

  After moving the non-defective individual substrate 12d (OK2) to a predetermined position, the concave portion of the discarded frame portion 13a of the printed wiring board 11a and the convex portion of the non-defective individual substrate 12d (OK2) fitted thereto are bonded with an adhesive. Then, the corrected printed wiring board 11a can be obtained.

  With the above correction, the printed wiring board 11a composed of the non-defective individual substrates 12a (OK1) and 12d (OK2) is obtained from the two sheets of printed wiring boards 11a and 11b that had to be discarded as defective products. It can be used as a non-defective two-piece substrate. Thereby, a manufacturing yield can be improved and disposal loss, such as material cost, labor cost, and equipment cost, can be reduced.

  Next, as Example 1, a bonding method for bonding a good individual substrate 12d (OK2) to the discarded frame portion 13a of the printed wiring board 11a will be described in more detail with reference to FIGS.

  FIG. 2 is an enlarged view of the bonding portion of FIG. In FIG. 2, the printed wiring board 11 from which the defective individual substrate is removed and the non-defective individual substrate 12 are attached and fixed on the first adhesive sheet. The convex portion 15 processed in a shape surrounding the base of the connecting limb portion 14 connected to the individual substrate 12 is fitted into the concave portion 16 processed in the discarded frame portion 13 of the printed wiring board 11, and the convex portion 15 A slit-like adhesive portion 17 for filling the adhesive is formed between the concave portion 16 and the concave portion 16 with a predetermined width.

  As a method for filling the adhesive, filling is performed using an inkjet. In the method using the ink jet, filling is performed by discharging an adhesive from the tip of the ink jet nozzle toward the slit-like adhesive portion 17. The slit-shaped adhesive portion 17 shown in FIG. 2 has a U-shape. In this case, the inkjet nozzle is moved relative to the printed wiring board 11 along the U-shape. However, the adhesive can be filled in the entire U-shaped slit-like adhesive portion 17 by discharging the adhesive.

  FIG. 3 is a cross-sectional view showing a state when the slit-like adhesive portion 17 of FIG. 2 is further enlarged and the adhesive is filled. In FIG. 3, the slit-like adhesive portion 17 is formed between the concave portion 16 provided in the discarded frame portion 13 of the printed wiring board 11 and the convex portion 15 provided on the non-defective individual substrate 12. Moreover, the recessed part 16 and the convex part 15 are not contacting, but the slit-shaped adhesion part 17 is formed as these clearance gaps. However, since the discarded frame portion 13 and the individual substrate 12 of the printed wiring board 11 are both attached to the first pressure-sensitive adhesive sheet 18, the adhesive 20 discharged from the inkjet nozzle 19 is the first pressure-sensitive adhesive sheet. 18 becomes a stopper and fills the slit-shaped adhesive portion 17. This makes it possible to prevent the adhesive 20 from spreading on the back side of the printed wiring board.

  In general, a thermosetting adhesive and an ultraviolet curable type are known as the types of adhesive, but the ultraviolet curable type is preferable for application to the present invention. In the case of a thermosetting adhesive, it is necessary to heat the adhesive when it is cured, but this heating causes the printed wiring board 11 and the individual substrate 12 to thermally expand, and before the adhesive 20 is cured, it is highly accurate. This is because the positional accuracy of the individual substrate 12 with respect to the printed wiring board 11 aligned in step 1 may deteriorate. Further, the printed wiring board 11 and the individual substrate 12 may be warped by heating, and a step may be generated in the bonding portion between the discarded frame portion 13 of the printed wiring board 11 and the individual substrate 12 before the adhesive 20 is cured. Because there is. On the other hand, in the case of an ultraviolet curable adhesive, there is no such a worry because it is not necessary to perform a heat treatment at the time of curing.

  Moreover, as a kind of 1st adhesive sheet 18, the thing of the type from which adhesive force falls by heating is preferable. Thereby, at normal temperature, the discard frame portion 13 of the printed wiring board 11 and the individual substrate 12 can be firmly fixed, and further, the first pressure-sensitive adhesive sheet 18 is heated by heating after the adhesive 20 is cured. This is because it can be easily peeled off from the discarded frame portion 13 of the printed wiring board 11, the individual substrate 12, and the cured adhesive 20.

  In addition, it is effective to use a combination in which the adhesive is an ultraviolet curable adhesive as described above and the first adhesive sheet 18 is of a type in which the adhesive strength is reduced by heating. By this combination, the discarded frame portion 13 and the individual substrate 12 of the printed wiring board 11 can be firmly fixed to the first pressure-sensitive adhesive sheet 18 until the adhesive is cured, and after the adhesive is cured, It is because the effect that the 1st adhesive sheet 18 can be easily peeled by heating can be exhibited.

  Since the first adhesive sheet 18 is peeled off from the discarded frame portion 13 of the printed wiring board 11, the individual substrate 12, and the cured adhesive 20, the original adhesive force is generated again when the temperature returns to room temperature. It can be reused as long as there is no dirt, foreign matter, etc.

  The reason for using the ink jet as a method of filling the adhesive is as follows. That is, the adhesive 20 discharged from the tip of the inkjet nozzle 19 is discharged into the air as a liquid column immediately after that, but there are a plurality of liquid columns of the adhesive 20 due to air resistance, the surface tension of the adhesive 20 itself, and the like. Will be separated into particles. Therefore, when the adhesive 20 reaches the slit-like adhesive portion 17, it is already in the form of particles.

  As a result, the so-called air bite void 8 shown in FIG. 5 that occurs when the columnar adhesive is filled from the tip of the conventional dispenser does not occur. This is because when the ink jet is used, the particle size of the adhesive 20 is smaller than the width of the slit-like bonding portion 17 and there is an air escape around the particle-like shape. In addition, because of the principle of inkjet, the particles of the adhesive 20 are filled so as to be struck at a high speed against the slit-shaped adhesive portion 17, so that air is pushed out around the adhesive 20 and air biting occurs. Never do.

  As described above in detail, according to the embodiment of the present invention, the void 8 due to the so-called air biting that has been generated by the conventional method can be prevented. It is possible to prevent rupture and secure a sufficient bonding area, to obtain sufficient fixing strength of the individual substrate 12 with respect to the discard frame portion 13, and to obtain high accuracy as the alignment accuracy of the individual substrate 12 with respect to the discard frame portion 13. Therefore, it is possible to provide a method for manufacturing a printed wiring board that can be used.

  The ink jet method and the shape of the ink jet nozzle used in the above description are not particularly specified. These can be appropriately selected from known ones. Further, the viscosity of the adhesive can be appropriately selected as a design matter so that an appropriate discharge state from the ink jet can be obtained.

  Further, in the present embodiment, the recess 16 and the protrusion 15 processed in a shape surrounding the base of the connection limb 14 on the discarded frame portion 13 of the printed wiring board 11 and the non-defective individual substrate 12 are rectangular as shown in FIG. However, this shape is not particular. Other shapes may be quadrangles such as trapezoids and rhombuses other than rectangles, and polygons such as triangles other than rectangles and pentagons. Moreover, not a polygon but an arc or a waveform may be used, and a saw tooth shape may be used. In any case, the adhesion area around the base of the connecting limb 14 can be increased, and the individual substrate 12 can be firmly fixed to the discard frame 13.

  Moreover, as a kind of the 1st adhesive sheet 18, although it was set as the type of which adhesive force falls by heating, it can also be made into the type of adhesive force falling by making low temperature conversely. In this case, the adhesive 20 can be peeled from the discarded frame portion 13 of the printed wiring board 11, the individual substrate 12, and the cured adhesive 20 by lowering the temperature after curing the adhesive 20.

  Note that the printed wiring board 11 that is a multi-piece substrate has been described with respect to a two-piece substrate. However, the printed wiring board 11 is not limited to a two-piece substrate. It goes without saying that it can be corrected to a non-defective product by this method.

  Next, as an embodiment of the present invention, the relationship between the particle diameter of the adhesive 20 ejected by inkjet and the width of the slit-like adhesive portion 17 will be described.

  In the present invention, it is important to optimize the particle size of the adhesive 20 discharged by inkjet. If the particle size is too large, there is a risk that the adhesive 20 protrudes from the slit-like adhesive portion 17. On the other hand, if the particle size is too small, it takes too much time to fill the adhesive 20 and the productivity deteriorates. It is.

  In recent years, printed wiring boards are becoming smaller and higher in density, and it is difficult to ensure a sufficient width of the slit-like adhesive portion 17 because of space as compared with conventional printed wiring boards. Under such circumstances, the relationship between the average particle diameter of the adhesive 20 ejected by inkjet and the width of the slit-like adhesive portion 17 is widely used to deal with a wide range from the conventional printed wiring board to the recent high-density printed wiring board. As a result of investigation, it was found that good results can be obtained when the following relationship is established as a set value of the particle diameter of the adhesive 20.

  That is, assuming that the width of the slit-shaped adhesive portion 17 is 0.1 mm (100 μm) to 3.0 mm (3000 μm), the average particle diameter of the adhesive 20 is 10 with respect to the width of the slit-shaped adhesive portion 17. It is preferably 0.01 mm (10 μm) to 2.7 mm (2700 μm) corresponding to% to 90%. Furthermore, the width of the slit-shaped adhesive portion 17 is 0.2 mm (200 μm) to 2.0 mm (2000 μm), and the average particle diameter of the adhesive 20 is 20% to 80% with respect to the width of the slit-shaped adhesive portion 17. Is preferably 0.04 mm (40 μm) to 1.6 mm (1600 μm). Furthermore, the width of the slit-shaped adhesive portion 17 is 0.3 mm (300 μm) to 1.5 mm (1500 μm), and the average particle diameter of the adhesive 20 is 30% to 70% with respect to the width of the slit-shaped adhesive portion 17. More preferably, it is 0.09 mm (90 μm) to 1.05 mm (1050 μm).

  Various methods are known for measuring the average particle size of the fine particles, but the average particle size used in this example is an integrated value in the particle size distribution obtained by the laser diffraction / scattering method (also called microtrack method). Mean particle size at 50%. The laser diffraction / scattering method is the most commonly used method to measure the particle diameter by utilizing the difference in the light intensity distribution of the diffracted and scattered light depending on the particle diameter when a laser beam is applied to the particle. Is the way. The particle size with an integrated value of 50% represents the particle size when the abundance ratio is 50%. In the laser diffraction / scattering method, the abundance ratio in the volume distribution is expressed in principle.

  The average particle diameter of the adhesive 20 can be controlled by a known method such as changing the diameter of the tip of the inkjet nozzle 19 or changing the discharge conditions. According to the inkjet method, the variation in particle diameter is extremely small as compared with fine particles atomized by a rotary atomizing bell-type coating gun. This is because it largely depends on the diameter of the tip of the inkjet nozzle 19. This is also one of the reasons for adopting the ink jet method as the filling method of the adhesive 20 in the present invention.

  In this embodiment, a printed wiring board having a thickness of 1.0 mm is used, the long side of the rectangular portion of the convex portion 15 of the individual substrate 12 in FIG. 2 is 4.0 mm, the short side is 2.0 mm, and the slit shape is It processed so that the width | variety of an adhesion part might be set to 1.0 mm. Moreover, it set so that the average particle diameter of the adhesive agent 20 discharged by an inkjet might be set to 0.4 mm (400 micrometers).

  Furthermore, after the discharge amount of the adhesive 20 per unit time is selected from a known range, the inkjet nozzle is positioned relative to the printed wiring board 11 along the U-shape of the slit-like adhesive portion 17. As a result of filling the adhesive while moving, the time required for filling per bonded portion was about 1 second.

  In addition, when the so-called throwing power in which the width of the slit-like adhesive portion 17 is the same and the plate thickness is larger than the above-described one is large, the adhesive may be filled by taking time as much as the filling amount of the adhesive is increased. The average particle diameter of the adhesive 20 may be determined based on the relationship with the width of the slit-shaped adhesive portion 17, and even in the above case, it is not necessary to change the average particle diameter of the adhesive 20. According to the ink jet, the discharge speed of the adhesive is very fast, so that even if the plate thickness is increased, the air in the slit-like adhesive portion 17 is pushed out around the fine particles of the adhesive 20 and air biting occurs. Because there is no. This is also one of the reasons for adopting the ink jet method as the filling method of the adhesive 20 in the present invention.

  After filling the adhesive, the adhesive is cured by irradiating ultraviolet rays, and then the printed wiring board is heated to peel the first pressure-sensitive adhesive sheet 18 from the printed wiring board, and the correction work is completed. After the correction, the entire work is completed through visual inspection such as the positional accuracy of the replaced individual substrate 12 and predetermined scratches and discoloration.

  Next, the Example at the time of using a 2nd adhesive sheet using FIG. 4 is demonstrated. FIG. 4 is a cross-sectional view showing a method for manufacturing a printed wiring board according to the embodiment of the present invention.

  In FIG. 4, the printed wiring board 11 is attached to the plate 22 via the first adhesive sheet 18 and the second adhesive sheet 21. As shown in FIG. 4, the second adhesive sheet 21 is pasted on the plate 22, the first adhesive sheet 18 is further pasted on the second adhesive sheet 21, and the first adhesive sheet The printed wiring board 11 is affixed on 18.

  As these sizes, the first pressure-sensitive adhesive sheet 18 is preferably larger than the printed wiring board 11. This is because the entire printed wiring board 11 can be fixed by the first adhesive sheet 18. The second pressure-sensitive adhesive sheet 21 is preferably larger than the first pressure-sensitive adhesive sheet 18. This is because the first adhesive sheet 18 can be further fixed to the second adhesive sheet 21. The plate 22 is preferably larger than the second adhesive sheet 21. This is because the second adhesive sheet 21 can be further fixed to the plate 22.

  As described above, the first pressure-sensitive adhesive sheet 18 serves to fix the printed wiring board 11 to the plate 22 and to function as a stopper for the adhesive discharged from the inkjet nozzle.

  However, when a gap is generated between the printed wiring board 11 and the first pressure-sensitive adhesive sheet 18 due to warpage of the printed wiring board 11 during filling or curing of the adhesive, an adhesive stopper is used. Cannot be fulfilled, and there is a risk that the adhesive spreads to the back side of the printed wiring board 11.

  With respect to this problem, the following measures can be taken with the configuration of FIG. In FIG. 4, the first pressure-sensitive adhesive sheet 18 and the second pressure-sensitive adhesive sheet 21 have the following characteristics. That is, the adhesive strength between the printed wiring board 11 and the first pressure-sensitive adhesive sheet 18 is characterized by being larger than the adhesive strength between the first pressure-sensitive adhesive sheet 18 and the second pressure-sensitive adhesive sheet 21. Further, the adhesive strength between the second pressure-sensitive adhesive sheet 21 and the plate 22 has a feature that it is larger than the adhesive strength between the first pressure-sensitive adhesive sheet 18 and the second pressure-sensitive adhesive sheet 21.

  In order to realize this, for example, the first pressure-sensitive adhesive sheet 18 has adhesive force only on one side, and the second pressure-sensitive adhesive sheet 21 has pressure-sensitive adhesive force on both sides. Conditions can be set by appropriately selecting or combining. Moreover, as a sheet material, a well-known material such as polyester such as PET, cellophane, vinyl resin or the like can be used, and a well-known material such as an acrylic pressure-sensitive adhesive can also be used as a method for imparting adhesive force. it can.

  With this configuration, even when the printed wiring board 11 is warped and the printed wiring board 11 is partially lifted with respect to the plate 22, the first adhesive sheet 18 can follow the printed wiring board 11. it can. That is, when a force in the upper direction is partially generated on the printed wiring board 11 due to warping, the first adhesive sheet 18 and the second adhesive sheet are interposed between the printed wiring board 11 and the first adhesive sheet 18. 21, peeling occurs between the first pressure-sensitive adhesive sheet 18 and the second pressure-sensitive adhesive sheet 21, the weakest of the three adhesive strengths between the second pressure-sensitive adhesive sheet 21 and the plate 22. Therefore, even if the printed wiring board 11 is partially lifted with respect to the plate 22, the adhesive state between the printed wiring board 11 and the first adhesive sheet 18 is maintained, and the first adhesive sheet 18 is maintained. The sealed state of the adhesive is still maintained.

  As described above, even when the printed wiring board 11 is warped and the printed wiring board 11 is partially lifted with respect to the plate 22, the adhesive filled in the slit-like adhesive portion is sealed by inkjet. It is possible to prevent the adhesive from spreading on the back side of the printed wiring board 11.

  The fixing of the printed wiring board 11 to the plate 22 can be maintained by the effects of the first adhesive sheet 18 and the second adhesive sheet 21. This is because even if the printed wiring board 11 is partially lifted, the adhesive force of the portion other than the raised portion in the plane of the printed wiring board 11 is secured. As a result, the positional relationship between the discarded frame portion constituting the printed wiring board 11 and a good individual substrate prepared for replacement with a defective product is maintained, and highly accurate alignment can be ensured.

  The present embodiment is useful for a thin printed wiring board 11 in which warpage is likely to occur, and a printed wiring board 11 having greatly different front and back pattern areas. In Example 1, the adhesive applied to the present invention is preferably an ultraviolet curable type rather than a thermosetting type. However, the thermosetting type adhesive or the ultraviolet curable type adhesive can be used in the present example. But it can also be used.

  The present embodiment is particularly useful in the filling of the adhesive using the ink jet as described in the first and second embodiments. In the filling using the ink jet, the adhesive particles are ejected from the ink jet nozzle at a high speed and filled so as to be struck against the first pressure-sensitive adhesive sheet 18, so that the printed wiring board 11 and the first pressure-sensitive adhesive sheet are filled. This is because it is necessary to maintain a sufficient adhesion state with 18. When the printed wiring board 11 is warped, if the adhesive state between the printed wiring board 11 and the first pressure-sensitive adhesive sheet 18 is weakened, the first pressure-sensitive adhesive is caused by the impact of the adhesive particles colliding with each other. This is because the sheet 18 is further peeled from the portion, and there is a risk that the adhesive spreads to the back side of the printed wiring board 11.

  As described above, the printed wiring board manufacturing method of the present invention has been able to prevent voids due to so-called air biting, so that the present invention prevents cracking and rupture of conventional adhesives and sufficiently secures the bonding area. It is possible to provide a method of manufacturing a printed wiring board that can sufficiently secure the fixing strength of the individual substrate with respect to the discarded frame portion and can obtain high accuracy as the alignment accuracy of the individual substrate with respect to the discarded frame portion. Therefore, it is useful as a method for manufacturing a printed wiring board used in various electronic devices such as personal computers, mobile communication devices, video cameras, and digital cameras.

11, 11a, 11b Printed wiring board 12, 12a, 12b, 12c, 12d Individual substrate 13, 13a, 13b Discarding frame part 14 Connecting limb part 15 Convex part 16 Concave part 17 Slit-like adhesive part 18 First adhesive sheet 19 Inkjet Nozzle 20 Adhesive 21 Second adhesive sheet 22 Plate

Claims (4)

A defective product in which the defective individual substrate is removed from a plurality of substrates including a defective individual substrate in a plurality of substrate substrates made of a plurality of individual substrates connected to the discard frame portion via the connecting limbs. A removal step;
A non-defective product preparation process for separately preparing non-defective individual substrates;
A non-defective product disposing step of disposing the non-defective individual substrate at a position where the defective individual substrate of the multiple substrate is removed;
A non-defective product bonding step of bonding the non-defective product individual substrate to the plurality of substrates obtained by removing the defective individual substrate;
The defective product removing step includes a step of processing into a shape having a recess on the side of the discarded frame portion in a shape surrounding a base of the connection limb portion of the individual substrate of the defective product,
The non-defective individual substrate is fitted into a recess of the discard frame portion when the non-defective individual substrate is arranged at a position where the defective individual substrate is removed from the plurality of substrates. A convex portion that forms a slit-like adhesive portion between the concave portion and
In the non-defective product arranging step, the non-defective product individual substrate is aligned with the plurality of substrates obtained by removing the defective individual substrate fixed through the first adhesive sheet previously attached on the plate. Arranged and fixed on the first pressure-sensitive adhesive sheet,
In the non-defective bonding step, the slit-shaped bonding portion is filled with an adhesive by inkjet and cured .
The first adhesive sheet is further affixed on the plate via a second adhesive sheet,
The adhesive strength between the plurality of substrates and the non-defective individual substrate and the first adhesive sheet is greater than the adhesive strength between the first adhesive sheet and the second adhesive sheet,
The method for producing a printed wiring board, wherein an adhesive strength between the second adhesive sheet and the plate is larger than an adhesive strength between the first adhesive sheet and the second adhesive sheet . The average particle diameter of the adhesive discharged by inkjet in the non-defective bonding step is in the range of 20% to 80% with respect to the width of the slit-shaped bonding portion. Manufacturing method of printed wiring board. The slit-shaped adhesive portion has a width in the range of 0.2 mm to 2.0 mm, and the average particle size of the adhesive discharged by inkjet in the non-defective bonding step is in the range of 0.04 mm to 1.60 mm. The printed wiring board manufacturing method according to claim 2, wherein the printed wiring board is provided. The method for manufacturing a printed wiring board according to claim 1, wherein the adhesive is of an ultraviolet curable type.

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