JP2006024813A - Printed circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed circuit board having no tendency to cause a short circuit by soldering between land parts or between end-face through holes when soldered to fix to a mother board. <P>SOLUTION: The printed circuit board has at least one recesses sagging from one side to an inner side of the printed circuit board and at least one protrusions of the end face other than the recesses at least on one side. The end-face through holes are arranged at the end face in the recesses and at the end face of the protrusion. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a printed circuit board, and more particularly to a printed circuit board suitable for increasing the reliability of soldering.

  A semiconductor element is mounted on a printed circuit board in order to improve durability, reliability, and workability (for example, Japanese Patent Laid-Open No. 7-122684). Hereinafter, a conventional printed circuit board and a mounting method for mounting a semiconductor element for such a purpose will be described.

  FIG. 8 shows a conventional printed circuit board 101 for mounting a semiconductor element. The printed circuit board 101 used for mounting a semiconductor element is sometimes referred to as a module board in order to distinguish it from a mother board described later.

The printed circuit board 101 has a region 102 for fixing a semiconductor element on one main surface and a wiring pattern 103 made of a metal thin film for electrical connection with the mounted semiconductor element. The wiring pattern 103 is generally composed of a plurality of wirings, and each extends to an end surface around the printed circuit board 101.
An end surface through hole 105 is provided on the end surface of the printed circuit board 101. The end surface through hole 105 refers to a semi-circular cut region extending from one main surface of the printed circuit board 101 to the other main surface. A metal thin film is deposited on the surface of the end surface through hole 105 by plating or the like. The diameter of the end face through hole 105 is about 0.3 mm to 1 mm.
In FIG. 8, the end face through-holes 105 are arranged on the four sides of the printed circuit board 101. However, some of them may be arranged on any one side by design.
Around each end face through hole 105, a land portion 104 made of a semicircular metal thin film pattern is disposed. This is formed due to a manufacturing problem of the printed circuit board 101, and is electrically connected to the metal thin film of the end face through hole 105 and the wiring pattern 103. However, in recent years, a printed circuit board having no land portion has been proposed due to an improvement in the manufacturing method (for example, JP-A-5-145219).
Since the printed circuit board without the land portion can narrow the interval between the wiring patterns, the end face through holes can be arranged with high density. However, since manufacturing is difficult, manufacturing cost will increase.
The land portion 104 is generally formed of a thin film that is thicker than the wiring pattern 103. Further, the shape is not limited to a semicircular shape, and may be formed in a square shape around the end surface through hole.
Generally, a printed circuit board 101 (module board) for mounting a semiconductor element is manufactured by cutting a plurality of large printed circuit boards formed in a matrix. That is, each cut piece becomes a module board. Examples of the cutting method include a cutting method using dicing or the like, a laser processing method, or a pressing method.
The semiconductor element is fixed and mounted with a paste or the like on a predetermined region 102 of the printed circuit board (module board) 101 manufactured as described above. Then, according to a known wire bonding technique, a predetermined electrode on the semiconductor element and a predetermined wiring pattern 103 on the printed circuit board 101 are electrically connected. Thereafter, the semiconductor element is covered with resin or the like including the wire.
The printed circuit board 101 of the module board processed in this way is fixed on another printed circuit board (motherboard) 110. FIG. 9 is an enlarged perspective view of one end surface through hole 105 when the printed circuit board 101 is mounted on the printed circuit board 110 of the mother board 101.
On the motherboard 110, a wiring pattern 112 and a terminal portion 111 electrically connected thereto are arranged. On the terminal portion 111, the end face through hole 105 of the module board 101 is aligned and the module board is placed. After the module board 101 is placed on the motherboard 110, the end face through hole 105 and the terminal portion 111 are electrically connected and fixed by solder (not shown).
The terminal portion 111 is preliminarily formed with cream solder or solder bumps. After the module board 101 is placed, the terminal portion 111 is heated and melted in a reflow furnace to be connected. Or you may connect using a soldering iron. When melted, the solder flows not only into the region of the end surface through hole 105 but also into the land portion 104 of the module board 101, thereby being firmly fixed to the motherboard 110. In order to prevent environmental pollution, solder that does not contain harmful substances such as lead has been used in recent years.
Japanese Patent Laid-Open No. 7-122684 JP-A-5-145219

In recent years, various semiconductor devices have been manufactured. Among them, those having a large number of electrodes (terminals provided on the semiconductor element for electrically connecting the semiconductor element and the outside) are manufactured. A printed circuit board on which such a semiconductor element is mounted is provided with a large number of end face through-holes in the same manner as the semiconductor element. On the other hand, the printed circuit board is required to have a small area. This is in order to reduce the size of a device that incorporates a printed circuit board as an electronic component.
As described above, the printed circuit board is required to have a larger number of end face through-holes on the four sides with a limited length. That is, it is required to increase the density of the end face through holes.
However, when the interval between the end face through holes becomes narrow in this way, when the solder is melted, it flows out into the adjacent end face through holes and causes a short circuit. For this reason, the problem that the yield and reliability deteriorated has arisen. Further, when investigated in more detail, this short circuit may occur not only at the interval between the end face through holes, but also when the interval between the land portion and the land portion or the interval between the conductor such as the wiring pattern and the land portion is narrow. found.
Solder has the property of flowing along the conductor when melted. When cream solder or solder bumps arranged on the motherboard are melted, the solder is also placed on the land on the module board in a melted state. Therefore, if the distance between the land part and the land part or the distance between the conductors such as the wiring pattern is narrow, the molten solder flows and short-circuits.
If priority is given to the density of the end face through hole, the radius of the end face through hole is 0.3 mm, the distance between the end face through holes is 0.5 mm, the land width is 0.5 mm, and the distance between the land portion and the land portion is 0.1 mm. Printed circuit boards are realized. However, some reduction in yield was allowed. Thus, the current situation is that either the yield or the density of the end surface through holes is sacrificed.
The present invention has been made in view of such problems, and is a printed circuit board with improved yield and reliability during soldering while maintaining the density of the end surface through holes, or the end surface while maintaining the yield. Provide a printed circuit board with increased through-hole density.

  In order to solve the above-mentioned problem, the printed circuit board according to the first aspect of the present invention is a printed circuit board in which a plurality of end surface through holes having a metal film are arranged on at least one side of the periphery, and the one side is the side And having at least one concave portion that is recessed toward the inside of the printed circuit board and at least one convex portion that is an end surface other than the concave portion, and at least one of the end surface through holes is an end surface in the concave portion. And at least one is arranged on the convex portion.

  A printed circuit board according to a second aspect of the present invention has a region for fixing a semiconductor element on one main surface, a wiring pattern electrically connected to the semiconductor element, and a metal film provided on at least one side of the periphery. A printed circuit board having a plurality of end surface through holes and a land part electrically connected to the wiring pattern and the metal film, wherein the one side is recessed from the side toward the inside of the printed circuit board. One or more concave portions and one or more convex portions that are end surfaces other than the concave portions, and at least one of the end surface through hole and the land portion is disposed on an end surface in the concave portion, and at least one of It arrange | positions at the said convex part.

  The printed circuit board according to a third aspect of the present invention is the printed circuit board according to any one of the first and second aspects, wherein an end surface where the end surface through-hole is disposed in the concave portion is substantially parallel to an end surface of the convex portion. It is.

A printed circuit board according to a fourth aspect of the present invention is the printed circuit board according to the third aspect, wherein one end face through hole is arranged in each of the concave portion and the convex portion.
A printed circuit board according to a fifth aspect of the present invention is the printed circuit board according to the second aspect, wherein an end surface of the recess in which the end surface through hole is disposed is substantially parallel to an end surface of the convex portion. The width of the end surface on which the end surface through hole is arranged is wider than the opening width of the concave portion on a straight line extending the end surface of the convex portion.

  A printed circuit board according to a sixth aspect of the present invention is the printed circuit board according to the fifth aspect, wherein a plurality of the concave portions and the convex portions are arranged, and one end face through hole is arranged in each of them. The interval between the land portions arranged in the concave portion is larger than the width of the wiring pattern connected to the land portion of the convex portion provided between the concave portions, and is provided between the concave portions. The distance between the land portions arranged in the convex portion is smaller than the width of the land portion of the convex portion, and the width of the wiring pattern connected to the land portion of the concave portion provided between the convex portions. It is larger and smaller than the width of the land portion of the concave portion provided between the convex portions.

  A printed circuit board according to a seventh aspect of the present invention is the printed circuit board according to the first or second aspect, wherein a plurality of end surface through holes are arranged in the recess.

According to the printed circuit board of the present invention, it is possible to increase the interval between the end face through holes without changing the side dimension of the printed circuit board. For this reason, it is possible to prevent short-circuiting between the end face through-holes or between the lands with solder, and the yield and reliability are improved.
Further, according to the printed circuit board of the present invention, the end face through holes can be arranged with high density if the yield is the same as before.

Hereinafter, a printed circuit board according to the present invention will be described in detail with reference to the drawings.
[First Embodiment]
FIG. 1 is an overall plan view of a printed circuit board 1 according to the first embodiment of the present invention, and FIG. 2 is an enlarged plan view of one side thereof. In order to facilitate understanding, the step d1 (described later) is shown larger than the actual one in this figure (the step d1 has a sufficient effect even with the radius of the end surface through hole, and the area of the printed circuit board 1 is It is almost the same level as before).

  The printed circuit board 1 has a region 2 for fixing a semiconductor element on one main surface and a plurality of wiring patterns 3 for electrical connection with the mounted semiconductor element. The wiring pattern 3 is composed of a plurality of wirings formed of a metal thin film, and each extends to the end faces of the four sides of the printed circuit board 1. The wiring pattern 3 is electrically connected to a metal thin film of an end face through hole 5 described later. Here, the width L6 of the wiring pattern 3 is 0.2 mm.

Each side of the printed circuit board 1 has a plurality of recesses 6 that are cut and recessed toward the inside of the printed circuit board 1. Here, “toward the inside of the printed circuit board” means “from the peripheral edge of the circuit board toward the center in the plane direction of the circuit board”. The recess 6 has an end surface 7 (hereinafter referred to as a side end surface 7 for convenience) and a back end surface 8 (also referred to as a back end surface 8) as side surfaces. Each side has a plurality of convex portions 9 (convex portion end surfaces 9) that are end surfaces other than the concave portions 6 and project from the concave portions 6. The space of the recess 6 (interval between the side end faces 7) becomes narrower toward the back end face 8. Here, the width L2 of the back end surface 8 is 0.6 mm, the opening width L1 of the concave portion on the straight line extending the end surface 9 of the convex portion is 0.7 mm, and the width L5 of the end surface 9 of the convex portion is 0.6 mm. Further, the back end face 8 and the end face 9 of the convex part are substantially parallel. If they are substantially parallel, the design is easy because the shape is not complicated. Here, the term “substantially parallel” refers to a parallel including a slight deviation due to a manufacturing error.
With such a shape, the angle at which the end surface 9 and the side end surface 7 of the convex portion intersect and the angle at which the side end surface 7 and the back end surface 8 intersect do not become acute angles. For this reason, the printed circuit board 1 can be easily manufactured and the yield can be improved.
Here, the space of the recess 6 has a trapezoidal shape that becomes narrower toward the back end face 8. However, the present invention is not limited to this. For example, even if it is a quadrangular shape, the above-described angle does not become an acute angle, and thus the same effect is obtained. Further, the back end face 8 and the end face 9 of the convex part are not parallel but one may be inclined with respect to the other. When tilted in this way, the angle can be an acute angle. However, even in such a case, there is an effect that a short circuit between end face through-holes described later is prevented.

An end surface through hole 5 and a land portion 4 are provided on the back end surface 8 and the end surface 9 of the convex portion. The end surface through hole 5 is a region cut in a semicircular shape from one main surface of the printed circuit board 1 to the other main surface. A metal thin film (not shown) is deposited on the surface of the end face through hole 5, and this metal thin film is electrically connected to the wiring pattern 3. Here, the diameter L4 of the end face through-hole 5 is 0.3 mm.
The land portion 4 is a semicircular metal thin film pattern provided around the end surface through hole 5. Here, the semicircular shape having a diameter L3 of 0.5 mm is used. Furthermore, in this embodiment, the land need not be formed.

Thus, the printed circuit board 1 of this Embodiment has a recessed part and a convex part in the at least 1 side. And the end surface through-hole 5 is provided in both a recessed part and a convex part. If it does in this way, since two adjacent end surface through-holes 5 are arrange | positioned through the space of a recessed part, both space | interval becomes wide. That is, the adjacent end surface through-holes 5 can be separated in the y direction by an interval of the step d1 with substantially the same dimension in the x direction in FIG. Accordingly, the distance between the land part 4 and the land part 4 and the distance between the land part 4 and the adjacent wiring pattern 3 are sufficiently separated.
For this reason, short-circuiting due to soldering is reduced and the yield is improved while the density of the end face through-holes is kept unchanged. In addition, the workability of soldering is improved and the manufacturing cost is reduced.
The printed circuit board 1 of the present embodiment is provided with one end surface through hole in one concave portion and one end surface through hole in one convex portion. In this way, since all the adjacent end face through holes are separated by the gap of the step d1, the above-mentioned effect is most preferably generated in all the end face through holes. However, a plurality of end surface through-holes 5 may be arranged in at least one of the concave portion or the convex portion. Even if it does in this way, the above-mentioned effect will arise in the end face through hole adjacent to a level difference part.

  Yield reduction due to solder shorting has been confirmed even when the level difference d1 is about the radius of the end face through hole. This is because even if the level difference d1 is about the radius of the end surface through hole, the adjacent end surface through holes are separated more than before, and the interval between the adjacent land portions is sufficiently separated. In the present embodiment, the level difference d1 is 0.2 mm.

On the other hand, since the interval between the end surface through-holes 5 increases as the level difference d1 increases, the above effect becomes more significant as the level difference d1 increases. However, if it exceeds 2 mm, the above-described effect becomes almost constant, so the step d1 is preferably 2 mm or less.
In the printed circuit board 1 of the present embodiment, the end face through holes 5 and the land portions 4 are arranged on all four sides. However, it goes without saying that it is only necessary to place them on one of the four sides.

The printed circuit board 1 of the present embodiment is manufactured as follows. First, a large-sized printed circuit board in which a plurality of printed circuit boards 1 are patterned in a matrix is prepared. In this large-sized printed board, the wiring pattern 3 of the printed board 1 shown in FIG. 1 is patterned, and end face through holes 5 and land portions 4 are provided. However, the end face through-hole 5 and the land portion 4 are formed in a circular shape instead of a semicircular shape.
Next, using a known dicing technique, a large printed circuit board is cut into small pieces. At this time, an extended line of the end face 9 of the convex portion is taken as a cutting line. At this time, the concave portion 6 is not formed on the small piece, and only the end surface through hole of the portion that becomes the end surface 9 of the convex portion is processed into a semicircular shape.

Next, by using a laser processing method, each small piece is processed along the portions to be the side end surface 7 and the back end surface 8 to form the recess 6. As a result, the end surface through hole of the back end surface 8 is processed into a semicircular shape. Then, the printed circuit board 1 is completed through a finishing process such as cleaning.
In addition, you may cut | disconnect only by a laser processing method, without using a dicing technique. Further, it may be cut by a known press method.
On the printed circuit board 1 processed in this way, a desired semiconductor element is fixed in a region 2 where the semiconductor element is fixed. After being fixed, the semiconductor element is electrically connected to the wiring pattern 3 of the printed board 1 by wire bonding. Thereafter, the semiconductor element is sealed with a resin or the like in order to improve durability.

The printed circuit board 1 is fixed on another printed circuit board (mother board). At this time, in order to electrically connect the mother board and the printed circuit board 1, the printed circuit board 1 is placed with the terminal portion of the mother board and the end face through hole 5 of the printed circuit board 1 aligned. Cream solder is arranged in advance on the terminal portion of the motherboard. After the printed circuit board 1 is placed, the cream solder is heated and melted. And the metal thin film of the end surface through-hole 5 and the terminal part of a motherboard are electrically connected, and the printed circuit board 1 is fixed to a motherboard.
FIG. 3 shows a modification of the printed circuit board according to the first embodiment, and is a partial plan view corresponding to FIG. The same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof is omitted. The difference from the printed circuit board 1 in FIGS. 1 and 2 is that the shape of the concave portion is not a trapezoidal shape but a pentagonal shape, and the central portion of the back end face 38 is further recessed inside the substrate.
If the back end surface 38 has such a shape, shorting during soldering is reduced, and the angle at which the side end surface 7 and the back end surface 8 intersect becomes further obtuse, making it easier to manufacture a printed circuit board. .

[Second Embodiment]
FIG. 4 is a printed circuit board 41 of the present invention according to the second embodiment, in which an image sensor 50 as a semiconductor element is mounted. And (a) is the whole top view, (b) is sectional drawing in the AA 'part. FIG. 5 is an enlarged view of the printed circuit board 41, (a) is an enlarged plan view of a portion B of FIG. 4, and (b) is an enlarged plan view of a part thereof.
An image sensor 50 is mounted on a predetermined portion of one main surface of the printed circuit board 41, and each electrode 51 of the image sensor 50 and a predetermined wiring pattern 43 of the printed circuit board 41 are electrically connected by a wire bond 52. Has been. The wiring pattern 43 is a plurality of wirings formed of a metal thin film, and extends to the end surface of the printed board 41. The wiring pattern 43 is electrically connected to the metal thin film in the end face through hole 45.

  A frame 53 is arranged on the printed circuit board 41 so as to surround the image sensor 50. Further, a glass plate 54 is fixed to the upper surface of the frame 53. A space 55 formed by the glass plate 54 and the frame 53 is filled with an inert gas such as nitrogen gas. In this way, the image sensor 50 is excellent in long-term durability because it receives light, is not mechanically damaged, and has a chemically stable atmosphere. .

  In the present embodiment, the printed circuit board 41 is provided with end face through holes 45 on the left and right sides (two sides extending in the y direction) in FIG. The two sides have a plurality of recesses 46 that are cut and recessed toward the inside of the printed circuit board 41. The recess 46 has a side end face 47 which is a side surface and a back end face 48 which is a back end face. The two sides have a plurality of convex end surfaces 49 which are end surfaces other than the concave portions 46 and project from the concave portions 46. Further, the rear end face 48 and the convex end face 49 are substantially parallel with a step d2.

One end surface through hole 45 and one land portion 44 are provided on each of the back end surface 48 and the convex end surface 49. Here, the end face through-hole 45 has a semicircular shape with a diameter L54 of 0.3 mm, and the land portion 44 has a semicircular shape with a diameter L53 of 0.5 mm.
As described above, in the printed circuit board 41 according to the present embodiment, the adjacent end surface through holes are separated by the distance of the step d2. Further, as described later, the distance between the land portion 44 and the land portion 44 and the distance between the land portion 44 and the adjacent wiring pattern 43 can be sufficiently separated.
Therefore, the printed circuit board 41 has an effect that the short circuit due to solder is reduced and the yield is improved as in the printed circuit board 1 according to the first embodiment.

The present embodiment is greatly different from the first embodiment in that the space of the recess 46 is shaped to become wider toward the back end face 48. Hereinafter, this point will be described in detail.
The printed circuit board 41 in the present embodiment is designed based on specifications from a camera on which it is mounted. As a result, the printed circuit board 41 has a structure in which the end face through-hole 45 is provided only in the limited region L7 on the left and right sides, although there is a dimensional freedom in the x direction (left and right direction in FIG. 4). . Specifically, the distance L7 is within 7 mm, and the number of end face through holes arranged on one side is 16. If the conventional technique is used, the distance between the land portions is required to be at least 0.1 mm. Therefore, when 16 end face through holes are arranged, L7 is 9.5 mm or more if the land portion diameter L53 is 0.5 mm. Distance is required. Therefore, it has been difficult to manufacture a printed circuit board that satisfies the above specifications with the conventional technology.

  In the printed circuit board 41 of the present embodiment, the space of the recess 46 becomes wider as it goes toward the back end face. End face through holes 45 and land portions 44 are arranged on the rear end face 48 and the convex end face 49. In other words, the width L52 of the back end surface 48 in which the end surface through hole 45 is disposed in the recess 46 is wider than the opening width L51 of the recess 46 on the straight line extending the protrusion end surface 49.

  With this configuration, when viewed from the direction of arrow C in FIG. 5, the land portion 44 disposed on the back end surface 48 and the land portion 44 disposed on the convex end surface 49 can be provided so as to overlap each other. That is, the land portion 44 disposed on the convex end surface 49 and the land portion 44 disposed on the back end surface 48 can be disposed so as to overlap in the y direction in the figure. In this way, it is possible to make the distance in the y direction narrower than the conventional distance by the distance between the overlapping parts and the distance between the land parts. Therefore, the end face through-holes and the land portions can be arranged with higher density in the y direction than before.

Specific distances between the respective portions of the printed circuit board 41 of the present embodiment are as follows. That is, the width L56 of the wiring pattern 43 is 0.12 mm. The distance L57 between the wiring pattern 43 and the land portion 44 is 0.12 mm, the width L52 of the back end surface 48 and the width L55 of the convex portion end surface 49 are 0.62 mm, and the opening width of the concave portion 46 on the straight line extending the convex end surface 49 L51 is 0.24 mm, and the level difference d2 is 0.5 mm.
If it does in this way, the land part 44 arrange | positioned at the convex part end surface 49 and the land part 44 arrange | positioned at the back end surface 48 will be arrange | positioned so that it may overlap in the y direction of a figure. For this reason, the printed circuit board 41 of the present embodiment can be narrowed by a distance of 0.2 mm between two adjacent land portions as compared with the conventional one. As a result, the entire area (one end land to the other end land) can be narrowed by approximately 2.5 mm, and L7 can be 6.95 mm.

Therefore, in addition to the effect of the first embodiment, the present embodiment also has an effect that the end face through holes are arranged at a high density and the printed circuit board can be miniaturized.
Of course, the present invention is not limited to the dimensions described above. However, in order to arrange the end face through holes with high density, it is important to satisfy the following conditions. First, the distance between the land portion 44 and the land portion 44 arranged in the two adjacent recesses 46 (the shortest distance between the end portion of one land portion 44 and the end portion of the other land portion 44) L61 is: It is larger than the width L62 of the wiring pattern 43 connected to the land portion 44 of the convex portion 49 provided between the concave portions 46. Here, if the width of the wiring pattern 43 differs depending on the location, the width of the wiring pattern 43 referred to here is a portion where the land portion 44 and the land portion 44 are adjacent (in other words, the land portion 44 and the land portion 44). The width of the wiring pattern 43 of the portion sandwiched by 44).

Second, the distance L61 between the land portions 44 disposed in the two adjacent recesses 46 is smaller than the width L63 of the land portion 44 of the projection 49 provided between the recesses 46.
Third, the distance L64 between the land portions 44 disposed on the two adjacent convex portions 49 is a wiring pattern connected to the land portion 44 of the concave portion 46 provided between the convex portions 49. 43 is greater than the width L65. Here, if the width of the wiring pattern 43 varies depending on the location, the width of the wiring pattern 43 here refers to the narrowest width of the wiring pattern.

Fourth, the distance L64 between the land portions 44 arranged on the two adjacent convex portions 49 is smaller than the width L66 of the land portion 44 of the concave portion 46 provided between the convex portions 49.
A printed circuit board that satisfies these four conditions has the effect of this embodiment. The width of the opening indicated by L51 is not particularly limited in size. However, it is preferable to appropriately determine the width of the opening based on the distance between the land portion 44 and the land portion 44 determined under the third and fourth conditions.

  Here, the yield is improved by increasing the density of the end face through holes and reducing the solder shorts. However, if the conventional yield is maintained, the distance L57 between the land portion of the recess end face 46 and the wiring pattern 43 can be further reduced, so that the density can be further increased.

The printed circuit board 41 of the present embodiment can be manufactured in the same manner as in the first embodiment. That is, it may be manufactured by combining a dicing technique and a laser processing method, or may be manufactured only by a laser processing method. Furthermore, it can also be manufactured using a pressing method. Further, the fixing to the mother board is the same as in the first embodiment.
The shape of the recess and the shape of the land are not limited to the shapes shown in FIGS. FIG. 6 is a modification of the printed circuit board according to the second embodiment, and is a partial plan view corresponding to FIG. The difference from the printed circuit board 41 in FIGS. 4 and 5 is the shape of the recess 66 and the shape of the land portion 64.

The recess 66 is cut into the printed circuit board 61 with the same width from the opening. And it is the shape cut | disconnected by the width | variety wider than the width | variety of an opening from the inner side part of the printed circuit board 61 from the land part 64 arrange | positioned at the convex part end surface 69. FIG. An end face through hole and a land portion are formed on the back end face 68. The point that the back side is formed wider than the opening is the same as the printed board 41 shown in FIGS. Even if the recess 66 is formed in this manner, the same effect as that of the printed circuit board 41 can be obtained, and since it is processed into a rectangle, there is an effect that the manufacturing is easy.
The land portion 64 is not a semicircular shape but a quadrangular shape. As described above, the land portion 64 may have a quadrangular shape or other polygonal shapes.

[Third Embodiment]
FIG. 7 is a partial enlarged view of the printed circuit board 71 according to the third embodiment of the present invention. The printed circuit board 71 of the present embodiment is different from the printed circuit board described so far in that an end surface through-hole is disposed on each of the three end surfaces forming the recesses. The other points are the same as those of the embodiment described so far, and the description is omitted.

In the printed circuit board 71, the recess 76 is formed by two side end surfaces 77-1 and 77-2 and a back end surface 78. The two side end faces 77-1 and 77-2 are parallel here. Further, the printed circuit board 71 has a convex portion 79 which is an end surface other than the concave portion 76 and protrudes from the concave portion 76. The convex end surface 79 and the back end surface 78 are parallel. Here, the step d3 between the convex end face 79 and the deep end face 78 is 0.5 mm, the width L71 of the deep end face 78 is 0.7 mm, and the width L75 of the convex end face 79 is 1.0 mm. Further, the width L74 of the end surface through hole 75, the width L73 of the land portion 74, and the width L76 of the wiring pattern 73 are set to 0.3 mm, 0.5 mm, and 0.2 mm, respectively.
The end surface through hole 75 and the land portion 74 are provided on the two side end surfaces 77-1 and 77-2 in addition to the convex portion 79 and the back end surface 78. As described above, the end surface through-hole provided in the recess 76 can be provided on the side end surface in addition to the back end surface 78.
The convex end surface 79 and the side end surface 77-1 are orthogonal to each other. For this reason, the end surface through hole 75-a arranged on the convex end surface 79 is opened in the y direction. On the other hand, the end surface through hole 75-b disposed in the side end surface 77-1 is opened in the x direction. That is, the two end face through-holes 75-a and 75-b are disposed so as to be inclined in the direction in which they face each other. Therefore, solder shorts between the end face through holes are greatly reduced both in distance and in the direction in which the end face through holes are arranged.

The land portion 74-b arranged on the side end face 77-1 and the land portion 74-a and the wiring pattern 73 arranged on the convex portion 79 can be sufficiently separated. Here, this distance is set to 0.15 mm. For this reason, a short circuit due to solder between the land portion 74-b and the land portion 74-a and the wiring pattern 73 is reduced.
On the other hand, the end surface through-hole 75-b disposed on the side end surface 77-1 and the end surface through-hole 75-c disposed on the back end surface 78 are both disposed in the recess 76 and are inclined to face each other. ing. However, the distance between the center positions of the end face through-holes is approximately 0.5 mm away, so that the solder does not short-circuit. Further, the land portion 74-b disposed on the side end surface 77-1 and the land portion 74-c disposed on the back end surface 78 can be sufficiently separated. Here, this interval is set to 0.14 mm. Therefore, a short circuit due to solder flowing in the land portion is reduced. The relationship between the end surface through hole 75-d and land portion 74-d arranged on the side end surface 77-2 and the end surface through hole 75-c and land portion 74-c arranged on the back end surface 78 is the same.

  In the printed circuit board 71, the two side end faces 77-1 and 77-2 are arranged in parallel. The distance L71 is 0.7 mm here. For this reason, the end face through-holes 75-b and 75-d and the land portions 74-b and 74-d arranged on both sides are sufficiently separated from each other, and a short circuit due to solder does not occur.

  In the present embodiment, the end surface through holes 75 are provided in all the end surfaces 76, 77-1, 77-2 of the recess 76. In this way, the density of the end face through holes 75 can be increased. However, the present invention is not limited to this, and it may be provided on one side end face and the back end face. Or it is not necessary to provide the end surface through-hole 75 in the back end surface 76 by arrange | positioning to the side end surface of both sides, or one side end surface. When not provided on the back end face, the width L71 of the recess 76 can be made narrower.

  If it carries out as mentioned above, it will be a value which exceeded 0.1 mm between all the adjacent land parts 74 or between the land parts 74 and the wiring pattern 73. FIG. Moreover, the space | interval of the adjacent end surface through-hole 75 can be about 0.5 mm or more. For this reason, the short circuit by solder is reduced.

  In the present embodiment, five end face through holes are provided at a distance of 2.2 mm. However, in the prior art, only 3 pieces can be provided at a distance of 2.2 mm. Therefore, as described above, the density of the end face through holes in the x direction in the figure can be increased. Further, if the density of the end face through holes is set as before, the above-described intervals can be made wider. For this reason, the short circuit by solder is further reduced.

The printed circuit board 71 of the present embodiment can be manufactured in the same manner as in the first embodiment. That is, it may be manufactured by combining a dicing technique and a laser processing method, or may be manufactured only by a laser processing method. Furthermore, it can also be manufactured using a pressing method. Further, the fixing to the mother board is the same as in the first embodiment.
Here, the land portion 74 has a quadrangular shape. However, the shape is not limited to this, and may be a semicircular shape as shown in FIG. Further, the shape of the recess may be the shape shown in FIGS. 5 and 6, for example. Furthermore, the shape may be any one of FIGS. 1 to 3.

  As described above in detail, the printed circuit board of the present invention can be used as a printed circuit board in which short circuit due to solder is reduced, and is particularly suitable as a module board.

1 is an overall plan view of a printed circuit board 1 of the present invention according to a first embodiment. It is the top view which expanded one side of the printed circuit board 1 of this invention which concerns on 1st Embodiment. It is a modification partial top view of the printed circuit board concerning a 1st embodiment. It is the printed circuit board 41 of this invention which concerns on 2nd Embodiment. It is the elements on larger scale of the printed circuit board 41 of FIG. It is a modification partial top view of the printed circuit board of the present invention concerning a 2nd embodiment. It is the elements on larger scale of the printed circuit board 71 of this invention which concerns on 3rd Embodiment. This is a conventional printed circuit board 101 for mounting a semiconductor element. FIG. 4 is an enlarged perspective view of one end face through hole 105 when the printed board 101 is mounted on a printed board 110 of a motherboard.

Explanation of symbols

1, 31, 41, 61, 71 Printed circuit board 2, 102 Area for fixing semiconductor elements 3, 43, 63, 73, 103 Wiring patterns 4, 44, 64, 74, 104 Land portions 5, 45, 65, 75, 105 End face through hole 6, 46, 66, 76 Concavity 7, 47, 77-1, 77-2 Side end face 8, 38, 48, 78 Back end face 9, 49, 69, 79 Convex part 50 Image sensor 51 Electrode 52 Wire Bond 53 Frame 54 Glass plate 101, 110 Printed circuit board 111 Terminal portion 112 Wiring pattern

Claims (7)

A printed circuit board in which a plurality of end face through-holes having a metal coating are disposed on at least one side of the periphery,
The one side has one or more concave portions that are recessed from the side toward the inside of the printed circuit board, and one or more convex portions that are end surfaces other than the concave portions,
At least one of the end surface through-holes is disposed on an end surface in the concave portion, and at least one of the end surface through holes is disposed on the convex portion. A region for fixing a semiconductor element on one main surface, a wiring pattern electrically connected to the semiconductor element, a plurality of end surface through holes provided on at least one side of the periphery and having a metal film, and the wiring pattern A printed circuit board having a land portion electrically connected to the metal coating,
The one side has one or more concave portions that are recessed from the side toward the inside of the printed circuit board, and one or more convex portions that are end surfaces other than the concave portions,
At least one of the end surface through hole and the land portion is disposed on an end surface in the concave portion, and at least one of the land portion is disposed on the convex portion.   3. The printed circuit board according to claim 1, wherein an end surface on which the end surface through hole is disposed in the concave portion is substantially parallel to an end surface of the convex portion. The printed circuit board according to claim 3 , wherein one end face through hole is disposed in each of the concave portion and the convex portion. The end surface where the end surface through-hole is disposed in the concave portion is substantially parallel to the end surface of the convex portion,
The printed circuit board according to claim 2, wherein a width of an end surface in which the end surface through hole is disposed in the concave portion is wider than an opening width of the concave portion on a straight line extending the end surface of the convex portion. A plurality of the concave portions and the convex portions are respectively disposed, and one end face through hole is disposed in each of the concave portions and the convex portions.
An interval between the land portions arranged in the concave portion is larger than a width of the wiring pattern connected to the land portion of the convex portion provided between the concave portions, and provided between the concave portions. Smaller than the width of the land portion of the convex portion,
The interval between the land portions arranged in the convex portion is larger than the width of the wiring pattern connected to the land portion of the concave portion provided between the convex portions, and provided between the convex portions. The printed circuit board according to claim 5, wherein the printed circuit board is smaller than a width of a land portion of the recessed portion formed. The printed circuit board according to claim 1, wherein a plurality of end surface through holes are arranged in the recess.