JP6711207B2 - Printed wiring board - Google Patents

Description

The present invention relates to a printed wiring board.

Conventionally, for example, a printed circuit board is used which is provided around a main body portion (a portion to be a product) and a main body portion at the time of manufacturing, and includes a discarding plate portion which is cut off when the main body portion is completed ( Patent Documents 1 to 3).

For example, Patent Document 1 discloses forming a perforation line and a slit for splitting between the main body and the discarding plate in order to easily cut off the discarding plate from the main body.

When manufacturing a multilayer printed circuit board, the copper foil layer provided on the surface of the base material (glass epoxy resin, etc.) is etched to form a pattern, and the base materials are adhered to each other with an epoxy adhesive and laminated. Then, a reflow process is performed to mount the component.

JP, 2003-152289, A JP-A-8-8565 JP, 10-322035, A

For example, when manufacturing using the above-mentioned printed circuit board, when each printed circuit board is a multilayer printed circuit board, for example, the printed circuit board due to the difference in the remaining rate of the copper foil in each layer, that is, the amount of the wiring pattern formed. Due to the difference in the coefficient of thermal expansion, the heat generated during reflow caused the printed circuit board to warp and twist. Due to this warp or twist, the flatness of the product board decreases, the mounting accuracy during component mounting decreases, which causes problems such as manufacturing inconvenience and the yield of finished product boards. Was.

The present invention has been made in view of the above points, and for example, provides a printed wiring board capable of reducing the warp and twist of the board at the time of manufacturing while maintaining the ease of separating the discarding plate portion. The purpose is to do.

The printed wiring board of the present invention is a printed wiring board comprising one or a plurality of laminated plate-shaped base materials and a metal pattern formed on the surface of each of the one or a plurality of plate-shaped base materials. The wiring board has a rectangular main body plate portion within the main surface of the printed wiring board and a discarding plate portion provided in the peripheral portion of the main body plate portion. Grooves extending along each of the four sides are formed, and a pair of parallel grooves among the grooves of the waste plate portion reaches the end portion of the printed wiring board. A perforation structure is formed in the region sandwiched by the pair of grooves, the perforation structure extending from an end of the discarding plate portion facing the main body plate portion toward a peripheral edge of the printed wiring board. To do.

It is a top view of the printed wiring board which is an example of the present invention. FIG. 2 is a cross-sectional view of the printed wiring board of FIG. 1 taken along line 2-2. It is a partially expanded top view of the printed wiring board of FIG. FIG. 4 is a cross-sectional view of the printed wiring board of FIG. 1 taken along line 4-4. It is a top view of the printed wiring board which is a modification.

A printed wiring board that is an embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a plan view of the printed wiring board 10. As shown in FIG. 1, the printed wiring board 10 is a product portion, and a product board portion 10A (one point in the drawing) as a rectangular main body portion on which a wiring pattern (not shown) according to the application of the product is formed. (The portion inside the chain line) and a discard plate portion 10B which is formed around the product substrate 10A and is a portion outside the product. The product board portion 10A is rectangular in the main surface of the printed wiring board 10 and has a short side portion SS and a long side portion LS.

In addition, in the example of FIG. 1, the four corners of the product substrate portion 10A have a rounded shape, but the shape of the corners may be changed depending on the application. Further, the direction along the long side portion LS is the carrying direction when processing such as mounting a component on the printed wiring board 10 or performing reflow processing on the printed wiring board 10 is performed.

2 is a cross-sectional view of the printed wiring board 10 taken along the line 2-2 of FIG. As shown in FIG. 2, in the printed wiring board 10, a copper foil layer provided on the surface of a base material 11 (glass epoxy resin or the like) as a plate-shaped base material made of an insulating material is etched to form a pattern 13 as a metal pattern. Is formed, and the base materials 11 are adhered to each other with an epoxy adhesive and laminated.

As shown in FIG. 2, a pattern 13 is formed over the entire surface of each base material 11 of the discard plate portion 10B. That is, when the pattern 13 is formed, the copper foil layer in the discard plate portion 10B is left without being etched. In other words, the pattern 13 is formed on all the regions between the base materials 11 on the discard plate portion 10B and on the front and back surfaces of the discard plate portion 10B.

Further, the copper foil layer on the surface of the base material 11 is removed in the region of the boundary between the product substrate portion 10A and the discarding plate portion 10B. That is, the pattern 13 is not formed in the boundary region between the product substrate portion 10A and the discard plate portion 10B.

As described above, since the pattern 13 is formed over the entire surface of the discard plate portion 10B, the bending rigidity against bending due to a force perpendicular to the main surface of the discard plate portion 10B is improved. Further, the coefficient of thermal expansion is averaged in the thickness direction of the discarding plate portion 10B, that is, the coefficient of thermal expansion in the thickness direction, in other words, the area above and below the center plane CS parallel to the main surface, It will be almost the same. This prevents warping or twisting of the discarding plate portion 10B when a temperature change due to reflow processing or the like is applied to the discarding plate portion 10B, which in turn warps or twists the entire printed wiring board 10 including the product board portion 10A. Is prevented.

In addition, in the discard plate portion 10B, the pattern 13 may not be formed on all the regions between the base materials 11 and the front surface and the back surface of the discard plate portion 10B. The pattern 13 may be formed so as to be symmetrical with the center planes CS of the base materials 11. As a result, in the printed wiring board 10, the areas above and below the center plane CS parallel to the main surface have substantially the same coefficient of thermal expansion, and warpage and twist due to the difference in the coefficient of thermal expansion are reduced. Further, the bending rigidity is improved due to the presence of the pattern 13.

As shown in FIG. 1, the V-shaped groove 15 is a groove formed on the front surface and the back surface of the printed wiring board 10 along each side of the product board portion 10A and its extension. The V-shaped groove 15 extends from the front surface and the back surface of the printed wiring board 10 to the inside of the printed wiring board 10 and has a V-shaped cross section (see FIG. 2 ). The V-shaped groove 15 is formed in plane symmetry with respect to the center plane CS.

The V-shaped groove 15 is formed along each long side portion LS of the product board portion 10A and its extension line, and each long side V-shaped groove 15A and each short side portion SS of the product substrate portion 10A and its extension line are formed. It includes a short side V-shaped groove 15B formed along.

In the drawings, as an example, both the long side V-shaped groove 15A and the short side V-shaped groove 15B are shown as reaching the end portion of the printed wiring board 10. However, the short side V-shaped groove 15B may be formed at least along the short side portion SS, and each of the long side V-shaped grooves 15A may reach the end portion of the printed wiring board 10. That is, it is sufficient that the pair of parallel V-shaped grooves 15 reach the end portion of the printed wiring board 10.

As shown in FIG. 2, the portion of the printed wiring board 10 where the V-shaped groove 15 is formed is thinner than the other portion where the V-shaped groove 15 is not formed. Further, the pattern 13 is not formed in a region in contact with the V-shaped groove 15 formed on the front surface and the back surface of the printed wiring board 10 and in a region sandwiched by the V-shaped grooves 15.

As a result, the portion in which the V-shaped groove 15 is formed is weak in bending force so that a folding line can be formed along the V-shaped groove. Therefore, when the printed wiring board 10 is bent while gripping both sides of the V-shaped groove 15, the printed wiring board 10 is bent along the V-shaped groove 15 and the printed wiring board 10 is bent along the V-shaped groove 15. It can be easily cut to easily remove the discarding plate portion 10B from the product substrate portion 10A.

Further, as described above, the pattern 13 is not formed in the region in contact with the V-shaped groove 15 formed on the front surface and the back surface of the printed wiring board 10 and the area sandwiched between the V-shaped grooves 15. .. Therefore, the pattern 13 is not exposed on the side surface of the product substrate portion 10A when removing the discarding plate portion 10B along the V-shaped groove.

The elongated hole 17 as a groove through hole is a through hole having a slender planar shape that penetrates the printed wiring board 10. The long hole 17 is formed by, for example, router processing. The long holes 17 include square long holes 17A formed along the four corners of the product substrate portion 10A and side long holes 17B formed intermittently along the substrate V-shaped groove 15.

In addition, in FIG. 1, as an example, the case where two long side holes 17B are provided along each of the long side portions LS and one side long hole 17B is provided along each of the short side portions SS is shown. ing. However, in order to facilitate the bending of the V-shaped groove 15 and the separation of the discarding plate portion 10B from the product substrate portion 10A, the elongated hole 17 has any number and length along the V-shaped groove 15. It is possible to form.

In addition, in FIG. 1, as an example, a case is shown in which the long side holes 17B are arranged at a position closer to the discard plate 10B side than the center line of the V-shaped groove 15, that is, the line connecting the bottom vertices. This arrangement is, for example, to prevent burrs from remaining on the product substrate portion 10A after the discarding plate portion 10B is removed. However, the long side holes 17B may be formed along the V-shaped groove 15, and may not necessarily be arranged so as to be offset from the center line of the V-shaped groove toward the discard plate portion 10B.

FIG. 3 is an enlarged view of an area AR which is a partial area of a corner of the printed wiring board 10 of FIG. As shown in FIG. 3, the end portion along the short side of the rectangular long hole 17A has a shape protruding toward the outer edge of the printed wiring board 10 in the direction along the long side portion LS of the product board portion 10A. The expansion hole portion E having is formed.

As shown in FIG. 1, the edge of the elongated hole 17 on the center side of the product substrate portion 10A is formed so as to coincide with the outer edge of the product substrate portion 10A. That is, the planar shape of the product board portion 10A has a contour formed by lines along the edges of the rectangular elongated holes 17A and the side elongated holes 17B facing the central side of the printed wiring board 10.

Since the elongated hole 17 is formed along the V-shaped groove 15 described above, it becomes easier to remove the discarding plate portion 10B from the product substrate portion 10A by bending along the V-shaped groove 15. Further, as described above, in the printed wiring board 10 of this embodiment, the elongated hole 17 is provided in addition to the V-shaped groove 15 as a structure for easily removing the discarding plate portion 10B.

As a result, as compared with the case of forming a slit for slitting and a perforation between the product substrate portion 10A and the discarding plate portion 10B as in Patent Document 1, it is more perpendicular to the main surface of the printed wiring board 10. It becomes possible to increase bending rigidity against bending due to force. The bonding strength between the product board portion 10A and the discard plate portion 10B, that is, the ease of removing the discard plate portion 10B and the rigidity of the printed wiring board 10 are determined by the depth of the V-shaped groove 15 and the length of the long hole. It can be adjusted by the number.

For example, the deeper the V-shaped groove 15 is, the more easily the discarding plate portion 10B is removed, and the lower the rigidity of the printed wiring board 10 is. Further, as the length and the number of the long holes are increased, the ease of removing the discarding plate portion 10B is increased and the rigidity of the printed wiring board 10 is decreased.

As shown in FIGS. 1 and 3, the perforation structure 19 has end cutouts 19A extending from a short side edge of the printed wiring board 10 in a direction along a long side LS of the product board portion 10A, This is a structure including a through hole 19</b>B having a circular planar shape which penetrates the printed wiring board 10. In other words, the perforation structure 19 extends from the end of the waste plate portion 10B facing the product board portion 10A toward the peripheral edge of the printed wiring board. Further, the perforation structure 19 is arranged in two opposite sides of the product substrate section 10A, here in a region sandwiched by extension lines of the opposite long side sections LS.

A plurality of through holes 19B are arranged in a line between the expanded portion E of the rectangular elongated hole 17A and the end through hole 19A along a direction parallel to the long side portion LS. In FIGS. 1 and 3, as an example, the through hole 19B extends from the line connecting the expanded portion E of the rectangular elongated hole 17A and the end through hole 19A to the center line AX along the long side of the printed wiring board 10. An example is shown in which they are lined up side by side.

FIG. 4 is a sectional view taken along line 4-4 of FIG. As shown in FIG. 4, the pattern 13 is also formed in a portion between each of the end through-holes 19A, the through-holes 19B and the extension E of the discard plate portion 10B, that is, a copper foil layer is provided. There is.

As described above, the pattern 13 is formed between each of the end through-holes 19A, the through-holes 19B, and the expanded portions E, so that the discard plate can be formed as compared with the case where the pattern 13 is not formed in these portions. Flexural rigidity against bending due to a force perpendicular to the main surface of the portion 10B is improved. This prevents warping or twisting of the discarding plate portion 10B when a temperature change is applied to the discarding plate portion 10 due to reflow processing or the like, and thus warps of the entire printed wiring board 10 including the product board portion 10A or Twist is prevented.

As shown in FIG. 1, the reference hole 21 is a through hole having a circular planar shape penetrating the printed wiring board 10. The reference holes 21 are provided at the four corners of the printed wiring board 10. That is, the reference hole 21 is formed in a region surrounded by the V-shaped groove 15 along the outer edge and the short side portion SS and the V-shaped groove 15 along the long side portion LS in the corner portion of the printed wiring board 10. ..

When the printed wiring board 10 is processed, a pin structure such as a reference pin provided in a carrying device that carries the printed wiring board 10 is inserted into the reference hole 21 and is held by the carrying device. By holding the printed wiring board 10 in this manner, the printed wiring board 10 is positioned by the carrying device, and for example, it is possible to prevent positional deviation in processing such as mounting deviation when mounting components on the printed wiring board 10.

The cutout piece portions 23 are a part of the discarding plate portion 10B, and are formed in the vicinity of the four corners of the printed wiring board 10, respectively. As shown in FIG. 3, it is a portion surrounded by the long side V-shaped groove 15A, the rectangular long hole 17A, and the perforated structure 19.

The cutout piece portion 23 is, for example, a portion that should be removed first when removing the discarding plate portion 10B when completing the product substrate portion 10A after the reflow process. In this removal, for example, first, a portion other than the cutout piece 23 of the printed wiring board 10 is fixed and held by a holding means (not shown). Next, the cutout 23 is gripped by gripping means (not shown) that grips the front and back sides of the cutout 23. That is, the cutout piece 23 is gripped so as to be sandwiched from both directions perpendicular to the main surface.

Next, the portion of the perforation structure 19 of the discard plate portion 10B is broken. For example, this breaking is performed by twisting the cutout piece portion 23 with the grip portion using the short side V-shaped groove 15B as a fulcrum, that is, by bending the short side V-shaped groove 15B. After the portion of the perforation structure 19 is broken, the cut-out piece portion 23 is further twisted and bent with respect to the entire remaining discarding plate portion 10B other than the cut-out piece portion 23 to form a portion of the short side V-shaped groove 15B. Is cut, and the cutout piece 23 and the remaining discarding plate portion 10B are cut.

After the removal of the cut-out piece portion 23, the product substrate portion 10A is fixedly held, and the long side V-shaped groove 15A is bent to break and cut, and is formed along the long side of the product substrate portion 10A. The discarding plate portion 10B that has been removed is removed.

After that, the product board portion 10A is fixedly held, and the short side V-shaped groove 15B is bent to break and cut, and the waste plate portion 10B formed along the short side of the product board portion 10A is removed. .. The process of bending the long side V-shaped groove 15A and the process of bending the short side V-shaped groove 15B may be performed in the reverse order of the above order.

When the cut-out piece 23 is removed from the printed wiring board 10, the pattern 13, that is, the copper foil is exposed in the broken cross section of the perforation structure 19 portion, but this cross section does not remain as the product board portion 10A. Since it is a part, there is no particular problem.

Further, as described above, the pattern 13 is not formed in the portion in contact with the V-shaped groove 15 and the region sandwiched by the V-shaped grooves 15. Therefore, when the printed wiring board 10 is bent along the V-shaped groove 15 to remove the discarding plate portion 10B from the product substrate portion 10A, the pattern 13, that is, the copper foil is exposed from the side surface of the product substrate portion 10A. do not do. Therefore, the defect of the product substrate portion 10A due to the exposure of the copper foil is prevented.

According to the printed wiring board 10 of the above-described embodiment, the pattern 13 is formed over the entire surface of each base material 11 of the discard plate portion 10B. In addition, before the removal of the discarding plate portion 10B, an end through hole which is a connection portion between the discarding plate portion 10B along the long side portion LS of the product substrate portion 10A and the discarding plate portion 10B along the short side portion SS. The pattern 13 is also formed in a portion between each of the 19A, the through hole 19B, and the expanded portion E.

With these, the bending rigidity against the force perpendicular to the main surface of the printed wiring board 10 of the entire discard plate portion 10B can be increased. Therefore, it is possible to enhance the bending rigidity of the printed wiring board 10 and suppress the warp or twist of the printed wiring board 10 when the printed wiring board 10 is subjected to high-temperature processing such as reflow processing.

Further, in the printed wiring board 10 of the above-described embodiment, the connecting portion between the product substrate portion 10A and the discarding plate portion 10B, that is, the separating portion is formed by the V-shaped groove 15 instead of the perforated structure by the through hole. .. Thus, the product board portion 10A and the waste plate portion 10B can be easily separated from each other, and the product board portion 10A and the waste plate portion 10B can be separated from each other with a perforated structure, while the connection between the product substrate portion 10A and the waste plate portion 10B is maintained. It is possible to increase the strength of the connecting portion with the portion 10B.

By increasing the strength of the connection portion in this way, the entire printed wiring board 10 including the product board portion 10A before the removal of the waste board portion 10B is supported by the support of the product board portion 10A by the waste board portion 10B having improved bending rigidity. It is possible to ensure the improvement of bending rigidity.

As described above, according to the printed wiring board 10 of the present invention, it is possible to enhance bending rigidity against bending due to a force perpendicular to the main surface. This prevents the printed wiring board 10 from warping or twisting when subjected to high-temperature processing such as reflow processing, for example, prevents displacement of the mounting position during mounting of components, and prevents defects in the product board portion 10A. It is possible to improve the yield at the time of manufacturing.

FIG. 5 shows an enlarged plan view of the printed wiring board of the modified example. FIG. 5 is an enlarged view of a portion similar to AR in FIG. As shown in FIG. 5, the end notch 25 may be provided so that the cutout piece 23 can be removed more easily. The end notch 25 is a hole that penetrates from the front surface to the back surface of the printed wiring board 10 and extends along the long side V-shaped groove 15A from the end portion of the long side V-shaped groove 15A. That is, at both ends of the long side V-shaped groove 15A, end notches 25 are formed as notches extending from the end of the printed wiring board 10 along the long side V-shaped groove 15A. ..

By forming the end notch 25, it is possible to further facilitate the break along the long side V-shaped groove 15A when removing the cutout piece 23, and to remove the cutout piece 23 more easily. Become.

In the above embodiments, the multilayer printed wiring board is described as an example, but the present invention can also be applied to a single-layer printed wiring board. At this time, the planar shape of the single-layer printed wiring board may be the same as that of the multilayer printed wiring board 10.

The various materials, configurations, shapes and the like in the above-described embodiments are merely examples, and can be appropriately selected according to the application and the like.

10 Printed Wiring Board 10A Product Board Section 10B Waste Plate Section 11 Base Material 13 Pattern 15 V-shaped Groove 17 Long Hole 19 Perforated Structure 21 Reference Hole 23 Cutout Piece 25 End Through Hole

Claims (6)

A printed wiring board comprising a laminated one or more plate-shaped base materials and a metal pattern formed on the surface of each of the one or more plate-shaped base materials,
The printed wiring board has a rectangular body plate portion in the main surface of the printed wiring board and a discard plate portion provided in the peripheral portion of the body plate portion,
Grooves extending along each of the four sides of the body plate portion are formed on the surface of the printed wiring board,
A pair of parallel grooves among the grooves of the discard plate portion reach the end of the printed wiring board, and the main body of the discard plate portion is provided in a region sandwiched by the pair of grooves. A printed wiring board having a perforated structure extending from an end facing the plate portion toward a peripheral edge of the printed wiring board. The printed wiring board according to claim 1, wherein the metal pattern is provided on the entire surface of each of the plate-shaped base materials of the waste plate portion . The perforation structure includes a plurality of through holes, and the metal pattern is provided on a surface of each of the plurality of plate-shaped substrates between each of the plurality of through holes. The printed wiring board according to 1 or 2. The printed wiring board according to any one of claims 1 to 3, further comprising a groove portion through hole formed along each of the grooves. 5. A notch extending from each end of the printed wiring board along each of the pair of grooves is formed at each end of the pair of grooves. The printed wiring board according to any one of 1. The printed wiring board according to claim 1, wherein a cross section of the groove is V-shaped.

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