JP2013143535A - Printed wiring board and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed wiring board which does not cause a short circuit between conductor patterns on both sides of a substrate even when ends of the conductor patterns on both sides are extended to a position the same with an end face of one end of the substrate.SOLUTION: A manufacturing method of a printed wiring board comprises: arranging an end face 2a of a terminal part 2A which is formed on one end of a conductor pattern 2 on a surface side on the same position with an end face 1a of one end of a substrate 1; arranging an end face 3a of a terminal part side end 3A which is opposite to the terminal part 2A, of a conductor pattern on a rear face side on the same position with the end face 1a of the one end of the substrate; arranging the end face of the terminal part of the conductor pattern on the surface side and the end face of the end of the conductor pattern to be aligned in a thickness direction closely to each other; and coating a soldered surface and the end face 2a of the terminal part 2A of the conductor pattern 2 on the surface side, and the end face 3a of the end of the conductor pattern on the rear face side with anticorrosion plated layers 12 and 13 composed of metals having less ionization tendencies than metals which form the conductor patterns, respectively.

Description

  The present invention relates to a printed wiring board in which conductor patterns are provided on the front surface and the back surface of a square substrate, respectively, and a method for manufacturing the same.

  In a printed wiring board in which conductor patterns are provided on the front surface and the back surface of a square substrate, in order to obtain desired characteristics, the end surface of the conductor pattern on the front surface side of the substrate and the end surface of the conductor pattern on the back surface side are connected to the end surface of the substrate. It may be necessary to provide in the state arrange | positioned in the same position. For example, in a printed wiring board constituting a microstrip line, in order to prevent an increase in transmission loss at a connection portion between a terminal portion of a strip conductor pattern and a central conductor of a coaxial connector connected to the terminal portion, The end surface of the terminal portion of the strip conductor pattern formed on the front surface side and the end surface of the end portion on the terminal portion side of the ground conductor pattern formed on the back surface side of the substrate are provided so as to be arranged at the same position as the end surface of the substrate. Is needed.

  However, if the end surface of the conductor pattern on the front surface side of the substrate and the end surface of the conductor pattern on the back surface side of the substrate are arranged at the same position as the end surface of the substrate, the end surface of the conductor pattern on the front surface side and the end surface of the conductor pattern on the back surface side Is placed close to each other through a minute distance corresponding to the thickness of the substrate, so that if the wiring board is exposed to moisture, the potential difference between the conductor pattern on the front surface side and the conductor pattern on the back surface side As a result, copper ions are eluted from the conductor pattern to the end surface of the substrate, and the copper ions move on the end surface of the substrate to form a so-called migration phenomenon in which a short-circuit path is formed on the end surface of the substrate. When such a phenomenon occurs, the conductive pattern on the front surface side and the conductive pattern on the back surface side of the substrate are eventually electrically short-circuited, which causes a problem that the life of the printed wiring board is shortened.

  In order to prevent the above problems from occurring, in the conventional printed wiring board, it is desirable to extend the end portion of the conductor pattern on the front surface side and the end portion of the conductor pattern on the back surface side to the same position as the end surface of the substrate. Even in such a case, it is often necessary to adopt a configuration in which the end portions of both conductor patterns are terminated at a position before the end face of the substrate.

  7 and 8 show a printed wiring board constituting a microstrip line as an example of a printed wiring board in which a conductor pattern is formed on both the front and back surfaces of a substrate. In the example shown in FIGS. 7 and 8, the strip conductor pattern 2 and the ground conductor pattern 3 are formed on the front surface and the back surface of the substrate 1, respectively. The printed wiring board 4 is formed by the substrate 1, the strip conductor pattern 2, and the ground conductor pattern 3. Is configured. The strip conductor pattern 2 and the ground conductor pattern 3 and the substrate 1 as a dielectric form a microstrip line.

  The printed wiring board shown in FIGS. 7 and 8 is manufactured by performing etching or plating on a copper-clad substrate in which a basic copper foil layer is formed on the front surface and the back surface of the substrate, respectively. In the illustrated example, as shown in FIG. 8, a strip conductor pattern is formed by a basic copper foil layer 201 formed on the surface of the substrate 1 and a copper plating layer 202 formed on the basic copper foil layer 201. 2, and the ground conductor pattern 3 is configured by the basic copper foil layer 301 formed on the back surface of the substrate 1 and the copper plating layer 302 formed on the basic copper foil layer 301.

  When this printed wiring board 4 is incorporated into a communication device or the like, it is necessary to connect the central conductor 5a of the coaxial connector 5 with the solder 6 to the terminal portion 2A formed at the end of the strip conductor pattern 2 on the surface side. Therefore, it is necessary to extend the terminal portion 2A of the conductor pattern 2 on the front surface side and the end portion 3A of the conductor pattern 3 on the back surface side to a position near the end portion of the substrate 1.

  In the printed wiring board described above, in order to reduce the power loss generated at the connecting portion between the microstrip line and the coaxial connector 5, the end surface 2a of the terminal portion 2A of the strip conductor pattern 2 on the front surface side and the ground conductor pattern on the back surface side It is desirable to provide the conductor patterns 2 and 3 on both the front and back surfaces so that the end surface 3a of the end portion 3A of the third end is located at the same position (on the same surface) as the end surface 1a of the substrate. However, if the end faces of the conductive patterns on the front and back sides are arranged at the same position as the end face of the substrate, migration occurs as described above and the life of the printed wiring board is shortened. As shown in FIG. 8, the end surface 2a of the terminal portion 2A of the conductor pattern 2 on the front surface side and the end surface 3a of the end portion 3A of the conductor pattern 3 on the back surface side are closer than the end surface 1a of the substrate 1 by a distance d (see FIG. 8). It is arranged at the position. A printed wiring board having the configuration shown in FIGS. 7 and 8 is disclosed in Patent Document 1, for example.

Japanese Patent Laid-Open No. 2001-177311

  As described above, in the prior art, even when it is desired that the end surfaces of the end portions of the conductor patterns 2 and 3 formed on the front surface and the back surface of the substrate are arranged at the same position as the end surface 1a of the substrate, In order to ensure durability, we had to take a structure that terminates the ends of the conductor patterns on the front and back at a position before the end face of the board, so we could not obtain a printed wiring board with a structure as specified It was.

  In particular, in a printed wiring board constituting a microstrip line, the end surface of the terminal portion of the strip conductor pattern provided on the front surface side of the substrate and the end surface of the end portion of the ground conductor pattern provided on the back surface side of the substrate are in front of the end surface of the substrate. If the arrangement at the position is taken, the power loss generated at the connecting portion between the terminal portion of the strip conductor pattern and the coaxial connector is increased, resulting in an increase in transmission loss.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a printed wiring board in which the end face of the end portion of the conductor pattern on both the front and back sides of the board can be arranged at the same position as the end face of the board without sacrificing durability. It is to provide.

  Another object of the present invention is to provide a method for producing the printed wiring board.

  The present invention includes a rectangular substrate and a conductor pattern on the front surface side and the back surface side formed on the front surface and the back surface of the substrate, respectively, and the conductor pattern on the front surface side is a soldering surface to which the external conductor is soldered. The conductor pattern on the back side has a terminal part side end opposite to the terminal part of the conductor pattern on the front side at a position near one end of the board. Of the conductor pattern and the conductor pattern on the back surface side, the exposed portion including the soldered surface and the end surface of the terminal portion of the conductor pattern on the front surface side, and the end surface of the terminal portion side end portion of the conductor pattern on the back surface side ( A printed wiring board on which a solder resist layer is provided so as to cover a portion other than a portion that needs to be exposed without being covered with a solder resist layer is an object.

The printed wiring board according to the present invention has the following configuration.
(A) The end surface of the terminal portion of the conductor pattern on the front surface side of the substrate and the end surface of the terminal portion side end portion of the conductor pattern on the back surface side are arranged at the same position as the end surface of one end of the substrate and covered with the solder resist layer Instead, they are arranged close to each other with the end face on one end side of the substrate in between.
(B) Metal whose soldering surface and end face of the terminal portion of the conductor pattern on the front surface side and the end face of the terminal portion side end portion of the conductor pattern on the back surface side have a smaller ionization tendency than the metal forming each conductor pattern It coat | covers with the anti-corrosion plating layer which consists of.

  As described above, the soldering surface and the end surface of the terminal portion of the conductor pattern on the front surface side of the substrate and the end surface of the terminal portion side end portion of the conductor pattern on the back surface side are arranged at the same position as the end surface of the substrate. In such a case, the soldering surface and the end surface of the terminal portion of the conductor pattern on the front surface side, and the end surface of the terminal portion side end portion of the conductor pattern on the back surface side have a smaller ionization tendency than the metal forming each conductor pattern. When the wiring board is exposed to moisture, when the wiring board is exposed to moisture, the end face of the terminal part of the conductor pattern on the front side and the terminal part of the conductor pattern on the back side are arranged adjacent to each other with the end face of the board in between. Since it is possible to suppress the elution of the metal ions that form the conductor pattern from the end face of the side end portion to the end face of the substrate, the front side conductor pattern and the back side conductor pattern are caused by migration. It is possible to prevent the phenomenon be contacted may occur.

  Accordingly, the specification is such that the soldering surface and end surface of the terminal portion of the conductor pattern on the front surface side of the substrate and the end surface of the terminal portion side end portion of the conductor pattern on the back surface side of the substrate are arranged at the same position as the end surface of the substrate. When required, a printed wiring board that satisfies the specifications can be obtained without impairing durability.

  In one aspect of the present invention, the conductor pattern on the front surface side is a strip conductor pattern constituting one of the pair of conductor patterns constituting the microstrip line, and the conductor pattern on the back surface side constitutes the other of the pair of conductor patterns. This is a ground conductor pattern.

  As described above, when the present invention is applied to the printed wiring board constituting the microstrip line, the end surface of the terminal portion of the strip conductor pattern and the terminal portion of the ground conductor pattern can be used without worrying about the deterioration of the durability due to migration. Since the end surface of the side end portion can be arranged at the same position as the end surface of the substrate, the printed wiring board can connect the central conductor of the coaxial connector to the terminal portion of the strip conductor pattern without increasing the transmission loss. Can be obtained.

  The anticorrosion plating layer is preferably composed of a gold plating layer applied to the outer surface of the conductor pattern via a nickel plating layer.

  Since gold is a noble metal with a very low ionization tendency, as described above, the soldering surface and end surface of the terminal portion of the conductor pattern on the front surface side of the substrate, and the end surface of the end portion of the conductor pattern on the back surface side of the substrate Are coated with a gold plating layer, the effect of preventing migration can be enhanced. In addition, as described above, if gold plating is formed on the outer surface of the conductor pattern via a nickel plating layer, gold molecules can be prevented from diffusing between copper molecules constituting the conductor pattern. The lifetime of the layer can be extended.

  The present invention is also directed to a method of manufacturing a printed wiring board having the above-described configurations by processing a rectangular copper-clad substrate having basic copper foil layers formed on both front and back surfaces of the substrate.

  In the manufacturing method according to the present invention, at least one hole including a long hole extending in the lateral direction of the copper-clad substrate is formed in the copper-clad substrate through a portion near one end in the vertical direction of the copper-clad substrate in the thickness direction. Formed on both the front and back sides of the copper-clad board, the plating process that forms the copper plating layer that covers the basic copper foil layer on both sides of the copper-clad board and the inner surface of the hole formed in the copper-clad board, After attaching an etching resist film on the copper plating layer, an unnecessary portion of the etching resist film is removed, and an etching resist having a pattern necessary for forming a conductor pattern of a predetermined shape on both the front and back surfaces of the substrate is formed. Etching resist formation process to be formed, and soldering surface for soldering the external conductor by etching the copper-clad substrate with the etching resist formed on both sides The conductor pattern on the surface side including the terminal part is formed on the surface of the substrate in a state where the end face of the terminal part is arranged at the same position as the inner face of the elongated hole, and the end face of the terminal part side end part is the elongated hole An etching process for forming a conductor pattern on the back surface, which is disposed at the same position as the inner surface of the substrate, on the back surface of the substrate, an etching resist removing process for removing the etching resist, and a solder for the terminal portion of the conductor pattern on the surface side of the copper-clad substrate Solder that applies solder resist to both front and back surfaces of the copper-clad board from which the etching resist has been removed in a state in which the exposed portion including the affixed surface and end surface and the end surface of the end of the conductor pattern on the back side of the copper-clad board is exposed. Resist forming step, terminal part of the conductor pattern on the surface side of the copper-clad substrate coated with solder resist, and the end of the conductor pattern on the back side exposed on the inner surface of the long hole An anti-corrosion plating process for forming an anti-corrosion plating layer so as to cover the surface, an extra portion of the copper-clad substrate at both ends of the long hole, and an extra portion of the copper-plated layer and the solder resist formed on the copper-clad substrate A cutting finishing process is performed to cut the portion and adjust the outer diameter of the printed wiring board.

  In a preferred embodiment of the printed wiring board according to the present invention, the anticorrosion plating layer covering the soldering surface and the end surface of the terminal portion of the surface-side conductor pattern has a portion other than the surface in contact with the substrate of the surface-side conductor pattern. The anticorrosion plating layer which is provided so as to cover the entire surface and covers the end surface of the terminal portion side end portion of the conductor pattern on the back surface side covers the entire portion excluding the surface in contact with the substrate of the conductor pattern on the back surface side. It is provided as follows.

  In such a printed wiring board, at least one hole including a long hole extending in the lateral direction of the copper-clad board through a portion near one end of the copper-clad board in the thickness direction is formed in the copper-clad board. Hole forming process to form, plating process to form a copper plating layer that covers the basic copper foil layer on both sides of the copper-clad board and the inner surface of the hole formed in the copper-clad board, and formed on both sides of the copper-clad board An etching resist film having a pattern necessary for forming a conductor pattern of a predetermined shape on both the front and back surfaces of the substrate by pasting an etching resist film on the copper plating layer formed and removing unnecessary portions of the etching resist film Etching resist forming process to form and soldering to solder the external conductor by etching the copper-clad substrate with the etching resist formed on both sides A conductor pattern on the front surface side including a terminal portion having a surface is formed on the surface of the substrate in a state where the end surface of the terminal portion is disposed at the same position as the inner surface of the long hole, and the end surface of the terminal portion side end portion is a long hole. An etching process for forming a conductor pattern on the back surface disposed on the same position as the inner surface of the substrate on the back surface of the substrate, an etching resist removing process for removing the etching resist, a conductor pattern on the surface side of the copper-clad substrate, and a conductor on the back surface side An anticorrosion plating process for forming an anticorrosion plating layer so as to cover the exposed surface of the pattern, and at least a soldering surface and an end surface of the terminal portion of the conductor pattern on the surface side of the copper-clad substrate coated with the anticorrosion plating layer Solder resist that applies solder resist to both front and back sides of copper-clad board with the end face of the conductor pattern on the back side of the copper-clad board coated with plating layer exposed The outer shape of the printed wiring board is prepared by cutting the forming step and the extra portion of the copper-clad substrate and the extra portion of the copper plating layer and the solder resist formed on the copper-clad substrate at both ends of the long hole. It can manufacture by performing a cutting finishing process.

  As described above, the anticorrosion plating layer that covers the soldering surface and the end surface of the terminal portion of the conductor pattern on the front surface side is provided so as to cover the entire portion excluding the surface in contact with the substrate of the conductor pattern on the front surface side. In addition, when the anticorrosion plating layer covering the end surface of the terminal portion side end portion of the conductor pattern on the back surface side is provided so as to cover the entire portion except the surface in contact with the substrate of the conductor pattern on the back surface side, the conductor pattern In addition to preventing irregularities on the surface of the conductor, and because the entire surface of the conductor pattern is formed of the same metal, the irregularities on the surface of the conductor pattern can degrade the frequency characteristics of the printed wiring board or cause transmission loss. Can be prevented from increasing. In particular, in the case of configuring a microstrip line, it is possible to improve the frequency characteristics and reduce transmission loss by eliminating the irregularities on the surface of the conductor pattern and forming the entire surface of the conductor pattern with the same metal. it can.

  Further, as described above, the anticorrosion plating layer covering the soldering surface and the end surface of the terminal portion of the conductor pattern on the front surface side is covered with the entire portion excluding the surface contacting the substrate of the conductor pattern on the front surface side. And providing an anticorrosion plating layer covering the end surface of the terminal portion side end portion of the conductor pattern on the back surface side so as to cover the entire portion excluding the surface in contact with the substrate of the conductor pattern on the back surface side. Since the pattern can be prevented from being deteriorated by radiation, durability of the printed wiring board used in an environment exposed to radiation such as outer space can be enhanced.

  In the present invention, the end surface of the terminal portion of the conductor pattern on the front surface side of the substrate and the end surface of the terminal portion side end portion of the conductor pattern on the back surface side of the substrate are arranged at the same position as the end surface of the substrate. The anticorrosion plating layer made of a metal having a smaller ionization tendency than the metal forming the respective conductor patterns on the soldering surface and the end surface of the terminal portion of the conductor pattern and the end surface of the terminal portion side end portion of the conductor pattern on the back surface side When it is necessary to have the end face of the conductor pattern on both the front and back sides of the board at the same position as the end face of the board, it is possible to do so without sacrificing durability. Can be obtained.

It is the perspective view which showed typically the structure of the principal part of one Embodiment of this invention. It is sectional drawing which showed typically the structure of the principal part of embodiment of FIG. (A) thru | or (G) are sectional drawings for demonstrating a series of processes of the manufacturing method which concerns on this invention. (A) thru | or (E) are sectional drawings for demonstrating a series of processes performed following the process shown by FIG. 3 among the series of processes of the manufacturing method which concerns on this invention. FIG. 5 is a top view of FIG. (A) thru | or (E) are sectional drawings which showed the modification of the process shown by FIG. 4 among a series of processes of the manufacturing method concerning this invention. It is the perspective view which showed typically the structure of the principal part of the conventional printed wiring board. It is sectional drawing which showed typically the structure of the principal part of the printed wiring board shown by FIG.

  1 and 2 show an embodiment of a printed wiring board according to the present invention. In the figure, 1 is a substrate made of an insulating material, 2 is a strip conductor pattern (conductor pattern on the front surface side) formed on the surface of the substrate 1, and 3 is a ground conductor pattern (conductor on the back surface side) formed on the back surface of the substrate 1. Patterns) 10 and 11 are solder resist layers on the front surface side and the back surface side that cover the strip conductor pattern 2 and the ground conductor pattern 3, respectively, and the printed wiring board 4 is constituted by these. In this printed wiring board, the substrate 1, the strip conductor pattern 2, and the ground conductor pattern 3 constitute a microstrip line.

  In this specification, one direction perpendicular to the thickness direction (height direction) of the rectangular substrate 1 is defined as the vertical direction of the substrate, and the direction perpendicular to both the thickness direction and the vertical direction is defined as the substrate. The horizontal direction. One of two opposing main surfaces (surface having the largest area) of the substrate 1 is the surface of the substrate, and the surface opposite to the surface is the back surface of the substrate.

  The strip conductor pattern 2 on the surface side of the substrate 1 extends long in the vertical direction of the substrate 1, and the terminal portion 2 </ b> A having a soldering surface has one end in the longitudinal direction of the strip conductor pattern 2 (one end side in the vertical direction of the substrate). (End part located in).

  The ground conductor pattern 3 on the back surface side of the substrate 1 is provided so as to cover the entire back surface of the substrate 1, and the end portion 3 </ b> A of the ground conductor pattern positioned on one end side in the vertical direction of the substrate 1 and the strip conductor pattern 2. The terminal portion 2 </ b> A is arranged in a state facing the thickness direction of the substrate 1. In the present specification, the end portion 3A of the ground conductor pattern facing the terminal portion 2A of the strip conductor pattern 2 is referred to as a terminal portion side end portion.

  In the present embodiment, the end surface 2a of the terminal portion 2A of the conductor pattern on the front surface side and the end surface 3a of the terminal portion side end portion 3A of the conductor pattern on the back surface side are arranged at the same position as the end surface 1a of one end of the substrate 1. Thus, the end surfaces 2a and 3a are not covered with the solder resist layer, and are disposed close to each other with the end surface 1a of the substrate 1 therebetween.

  In the present embodiment, the soldering surface (surface parallel to the surface of the substrate) and the end surface 2a of the terminal portion 2A of the conductor pattern 2 on the front surface side, and the end surface 3a of the terminal portion side end portion 3A of the conductor pattern 3 on the back surface side However, it is covered with an anticorrosion plating layer made of a metal having a smaller ionization tendency than the metal (copper in this embodiment) forming each conductor pattern.

  In the illustrated example, the soldering surface and the end surface 2a of the terminal portion 2A of the conductor pattern 2 on the surface side of the substrate are covered with the anticorrosion plating layer 12, and this anticorrosion plating layer 12 covers a part of the conductor pattern 2 on the surface side. There is no. Further, the end surface 3a of the terminal portion side end portion 3A of the conductor pattern 3 on the back surface side is covered with the anticorrosion plating layer 13, and this anticorrosion plating layer 13 forms a part of the conductor pattern 3 on the back surface side.

  In the present embodiment, the anticorrosion plating layers 12 and 13 are made of a gold plating layer which is the most ideal plating layer as the anticorrosion plating layer. In order to prevent gold molecules constituting the gold plating layer from diffusing between copper molecules constituting the conductor pattern and disappearing, the gold molecules move between the gold plating layer and the conductor pattern. A nickel plating layer is formed as a barrier for preventing the above.

  The printed wiring board 4 shown in the drawing is manufactured by subjecting a copper-clad substrate having base copper foil layers 201 and 301 formed on the front and back surfaces of a substrate 1 made of an insulating material to a base material, and performing plating and etching on the substrate. Is done. The illustrated substrate 1 is a substrate of a copper-clad substrate that is a base material. In this embodiment, the strip conductor pattern 2 is formed by etching the basic copper foil layer 201 on the surface side of the copper-clad substrate and the copper plating layer 202 formed on the basic copper foil layer 201. The ground conductor pattern 3 is constituted by the basic copper foil layer 301 on the back side of the copper-clad substrate and the copper plating layer 302 formed on the basic copper foil layer 301.

  The surface-side solder resist layer 10 is exposed without being covered with the solder resist layer (not covered with a solder resist layer) on the surface side of the printed wiring board including the soldering surface and the end surface 2a of the terminal portion 2A of the conductor pattern 2 on the surface side. It is provided so as to cover the part other than the necessary part). Further, the solder resist layer 11 on the back surface side includes the end surface 3a of the terminal portion side end portion 3A of the ground conductor pattern 3 on the back surface side and a portion (not shown) to which soldering is performed. It is provided so as to cover a portion other than the required exposure portion. In addition to the parts to be soldered, the exposed parts on both the front and back sides of the printed wiring board include parts that are placed in electrical contact with the chassis when the printed wiring board is attached to the chassis, etc. In addition, a portion that is screwed to the chassis or the like to fix the printed wiring board to the chassis or the like is included.

  When the printed wiring board 4 according to the present embodiment is incorporated into a device such as a communication device, as shown in FIG. 2, the central conductor of the coaxial connector 5 is placed on the soldering surface of the terminal portion 2A of the conductor pattern 2 on the surface side. 5a is applied, and the central conductor 5a is connected to the soldering surface of the terminal portion 2A by the solder 6.

  As in this embodiment, the end surface 2a of the terminal portion 2A of the conductor pattern 2 on the front surface side of the substrate and the end surface 3a of the terminal portion side end portion 3A of the conductor pattern 3 on the back surface side of the substrate are the same as the end surface 1a of the substrate 1. In the case of arranging at the position, the soldering surface and the end surface 2a of the terminal portion 2A of the conductor pattern 2 on the front surface side, and the end surface 3a of the terminal portion side end portion 3A of the conductor pattern 3 on the back surface side, If the printed wiring board is exposed to moisture when it is covered with an anticorrosive plating layer (in this embodiment, a gold plating layer) made of a metal that has a lower ionization tendency than the metal to be formed, it will be adjacent to the substrate. Since it is possible to suppress the elution of metal ions from the end surface 2a of the terminal portion of the conductor pattern on the front surface side and the end surface 3a of the terminal portion side end portion of the conductor pattern on the back surface side to the end surface 1a of the substrate, Maigure This can prevent the life of the printed wiring board from being shortened.

  Therefore, when it is necessary to have a specification in which the end face of the conductor pattern on the front side of the board and the end face of the conductor pattern on the back side are located at the same position as the end face of the board, the specification is not compromised. A proper printed wiring board can be obtained.

  Next, a method of manufacturing the printed wiring board 4 according to the present invention will be described with reference to FIGS. In the manufacturing method of the present invention, as shown in FIG. 3 (A), a copper-clad substrate 4 ′ having basic copper foil layers 201 and 301 formed on the front and back surfaces of the substrate 1, respectively, is used as a base material. A printed wiring board is manufactured by etching or plating the base material.

  In the manufacturing method of the present invention, first, as shown in FIG. 3B, the copper-clad substrate 4 ′ is penetrated in the thickness direction through a portion near one end in the longitudinal direction (left-right direction in FIG. 3) of the copper-clad substrate 4 ′. A hole forming step is performed in which at least one hole including a long hole 15 (see FIG. 5) extending in the horizontal direction (direction perpendicular to the paper surface of FIG. 3) is formed in the copper-clad substrate. In the example shown in FIG. 3, only the long holes 15 are formed in this drilling step. However, when other holes such as through holes for connecting between the conductor patterns on both the front and back surfaces of the substrate are necessary, Holes are also formed in this drilling process.

  After the drilling step is completed, as shown in FIG. 3 (C), the basic copper foil layers 201 and 301 on both the front and back surfaces of the copper-clad substrate and the inner surface of the hole 15 formed in the copper-clad substrate are thin. After performing electroless plating so as to form a copper plating layer, a plating process is performed in which electrolytic plating is performed on the copper plating layer by electroless plating to form a copper plating layer 16 having a predetermined thickness.

  After performing the plating step, as shown in FIG. 3D, photosensitive etching resist films 17 and 17 are attached on the copper plating layers 16 formed on the front and back surfaces of the copper-clad substrate, A pattern film that covers a portion that should not be exposed in order to form a conductor pattern is attached to the top. Next, the etching resist films 17 and 17 are exposed and developed, and then the pattern film is peeled off, and the portion of the etching resist film that has not been exposed (the portion that was not covered with the pattern film) is removed by the remover. As shown in FIG. 3 (E), an etching resist forming step for forming etching resists 17 'and 17' having a pattern necessary for forming a conductor pattern of a predetermined shape on both the front and back surfaces of the substrate 1 is performed.

  In the present embodiment, holes 17a ′ and 17a ′ having the same shape as the long holes 15 formed in the copper-clad substrate are formed in the etching resists 17 ′ and 17 ′ formed on both the front and back surfaces of the copper-clad substrate in the etching resist formation process. It is formed in alignment with the long hole 15. Further, a slit 17b 'is formed in the etching resist 17' on the surface side so as to be positioned near the end portion on the opposite side to the terminal portion 2A of the strip conductor pattern 2 to be formed. Further, the etching resist 17 ′ on the surface side is provided so as to form a portion 16 a exposed at a portion near the end located on the opposite side to the long hole 15 of the copper plating layer 16 on the surface side of the substrate 1. Yes.

  Next, the copper-clad substrate having the etching resist formed on both the front and back surfaces is etched, and as shown in FIG. 3 (F), a strip conductor including a terminal portion 2A having a soldering surface for soldering the external conductor The pattern 2 is formed on the surface of the substrate 1 with the end surface 2a of the terminal portion 2A being located at the same position as the inner surface of the long hole 15, and the end surface 3a of the terminal portion side end portion 3A is in contact with the inner surface of the long hole 15. An etching process for forming the ground conductor pattern 3 arranged at the same position on the back surface of the substrate 1 is performed.

  In the etching process, the portion of the copper plating layer 16 covering the inner surface of the long hole 15 is removed, and the end surface 1a of the substrate 1 is exposed. Further, by removing the copper plating layer covering the inner surface of the long hole 15, the copper plating layer 16 has a copper plating layer 202 covering the base copper foil layer 201 on the front surface side of the substrate and a base on the back surface side of the substrate. It is separated into a copper plating layer 302 covering the copper foil layer 301. Further, in the present embodiment, a portion corresponding to the slit 17b ′ formed in the etching resist 17 ′ on the front surface side is etched, so that the strip conductor pattern 2 is close to the end portion on the side opposite to the terminal portion 2A. A slit 2b is formed in the conductor pattern 2, and the strip conductor pattern 2 is divided into two parts. Further, by removing the ends of the basic copper foil layer 201 and the copper plating layer 202 on the surface side of the substrate on the other end side in the vertical direction of the substrate 1 by etching, a portion 1b near the other end in the vertical direction of the substrate 1 is removed. The surface of is exposed.

  After performing the etching process, as shown in FIG. 3G, an etching resist removing process is performed to remove and remove the etching resists 17 'and 17' on both the front and back surfaces.

  After removing the etching resist, as shown in FIGS. 4A and 4B, on the soldering surface and end surface 2a of the terminal portion 2A of the strip conductor pattern 2 formed on the front surface side of the substrate and on the rear surface side of the substrate. Solder resist for applying photosensitive solder resists 10 and 11 to both front and back surfaces of the copper-clad substrate from which the etching resist has been removed in a state where the end surface 3a of the terminal portion side end portion 3A of the formed ground conductor pattern 3 is exposed. A formation process is performed. By removing the end portion of the conductor pattern 2 on the surface side at the other end side in the vertical direction of the substrate by etching, the surface of the portion 1b (see FIG. 3F) near the other end in the vertical direction of the substrate 1 is exposed. Therefore, the solder resist 10 on the surface side is formed so as to cover the end surface of the end portion on the opposite side to the terminal portion 2A of the strip conductor pattern 2.

  In the solder resist forming step, as shown in FIG. 4A, the entire strip conductor pattern 2 formed on the front surface side of the substrate 1 and the ground conductor pattern 3 formed on the back surface of the substrate 1 are covered. After the photosensitive solder resists 10 and 11 are formed, a pattern film is applied to the portion covering the soldering surface of the terminal portion 2A of the strip conductor pattern 2 among the respective portions of the solder resist 10 on the surface side. In the pasted state, the solder resists 10 and 11 are exposed and developed. Next, the pattern film is peeled off, and the portion of the solder resist 10 that has not been exposed (the portion that was covered with the pattern film) is removed by the remover. As shown in FIG. The soldering surface of the portion 2A and the end surface 2a of the terminal portion 2A are exposed. In FIG. 4B, 10a is a notch formed in the solder resist 10 on the front surface side to expose the soldering surface of the terminal portion 2A, and 11a is an end portion on the terminal portion side of the ground conductor pattern 3. This is the end face of the solder resist 11 on the back surface side arranged on the same plane as the end face 3a.

  After performing the solder resist formation step, if necessary, as shown in FIG. 4C, marks 20 such as identification characters and figures are printed on the surface of the solder resist 10 using symbol printing ink. The symbol printing process is performed.

  Next, as shown in FIG. 4D, the anticorrosion plating layer 12 covering the soldering surface and the end surface 2a of the terminal portion 2A of the strip conductor pattern 2 on the surface side of the copper-clad substrate on which the solder resist 10 is applied, An anticorrosion plating step is performed for forming an anticorrosion plating layer 13 covering the end surface 3a of the terminal portion side end portion 3A of the ground conductor pattern 3 on the back surface side exposed on the inner surface of the hole 15. In the present embodiment, as described above, the anticorrosion plating layer 12 is formed by performing gold plating on the soldering surface and the end surface 2a of the terminal portion 2A of the strip conductor pattern 2 via the nickel plating layer. Further, the anticorrosion plating layer 13 is formed by performing gold plating on the end surface 3a of the terminal portion side end portion 3A of the ground conductor pattern 3 on the back surface exposed on the inner surface of the long hole 15 via a nickel plating layer. The

  After forming the anticorrosion plating layers 12 and 13, router processing is performed on the extra portions of the copper-clad substrate and the extra portions of the copper-plated layer and solder resist formed on the copper-clad substrate at both ends of the long hole 15. A finished cutting process is performed to cut the outer diameter of the printed wiring board to adjust the outer diameter of the printed wiring board, and the completed printed wiring board 4 is obtained as shown in FIG. When performing the router processing, the movement trajectory of the router bit is set so as not to damage the anticorrosion layers 12 and 13.

  When the printed wiring board 4 is manufactured by the above method, the soldering surface and the end surface 2a of the terminal portion 2A of the strip conductor pattern 2 formed on the front surface side of the substrate, and the ground conductor pattern 3 formed on the back surface side of the substrate. Since the end surface of the terminal portion side end portion 3A is covered with the anticorrosion plating layer, migration occurs between the end surface of the terminal portion of the strip conductor pattern 2 and the end surface of the terminal portion side end portion of the ground conductor pattern. It can suppress and it can prevent that the durability of a printed wiring board falls.

  In the printed wiring board manufactured by the method of the above embodiment, the end portion of the strip conductor pattern 2 opposite to the terminal portion 2A is terminated at a position before the other end in the vertical direction of the substrate 1, Since the end surface of the end portion of the strip conductor pattern 2 opposite to the terminal portion 2A is covered with the solder resist 10, there is no possibility that migration occurs on the other end side of the substrate 1 as well.

  In the above embodiment, the anticorrosion plating layer 12 is provided so as to cover only the soldering surface and the end surface 2a of the terminal portion 2A of the conductor pattern on the surface side of the substrate, and the end surface of the terminal portion side end portion of the conductor pattern 3 on the back surface side. Although the anticorrosion plating layer 13 is provided so as to cover only 3a, the anticorrosion plating layer 12 covering the soldering surface and the end surface 2a of the terminal portion 2A of the conductor pattern 2 on the surface side is provided on the substrate of the conductor pattern 2 on the surface side. An anticorrosion plating layer 13 is provided so as to cover the entire portion excluding the contact surface, and covers the end surface 3a of the terminal portion side end of the conductor pattern 3 on the back surface side, and contacts the substrate of the conductor pattern 3 on the back surface side. You may make it provide so that the whole part except the surface which covers may be covered. That is, the anticorrosion plating layers 12 and 13 may be formed so as to cover the entire portions of the conductor patterns 2 and 3 on both the front and back surfaces of the substrate other than the portions in contact with the respective substrates.

  As described above, when the anticorrosion plating layers 12 and 13 are formed so as to cover the entire portions of the conductor patterns 2 and 3 on both the front and back surfaces of the substrate other than the portions in contact with the respective substrates, as shown in FIG. After performing the etching resist removal process shown, the processes of FIGS. 6A to 6E are performed to manufacture a printed wiring board.

  That is, after the etching resist removing step shown in FIG. 3G is performed, as shown in FIG. 6A, each of the conductor pattern 2 on the front surface side and the conductor pattern 3 on the back surface side of the copper-clad substrate 1 is exposed. An anticorrosion plating process is performed to form the anticorrosion plating layers 12 and 13 so as to cover the entire surface. Next, as shown in FIGS. 6B and 6C, a printed wiring board including a soldered surface and an end surface 2a of the terminal portion 2A of the conductor pattern 2 on the surface side of the copper-clad substrate covered with the anticorrosion plating layer 12 And the exposed portion on the back side of the printed wiring board including the end surface 3a of the end portion of the conductor pattern 3 on the back side of the copper-clad substrate coated with the anticorrosion plating layer 13 was exposed. In this state, a solder resist forming process is performed in which the solder resists 10 and 11 are applied to both the front and back surfaces of the copper-clad substrate.

  In the solder resist formation step, first, as shown in FIG. 6B, a photosensitive solder resist is formed so as to cover the entire strip conductor pattern 2 formed on the surface side of the substrate 1 and covered with the anticorrosion plating layer 12. A photosensitive solder resist 11 is formed so as to cover the entire ground conductor pattern 3 formed on the back surface of the substrate 1 and covered with the anticorrosion plating layer 13. Next, the solder resist 10 is exposed in a state in which the pattern film is attached to the portion covering the soldering surface of the terminal portion 2A of the strip conductor pattern 2 among the portions of the solder resist 10 on the surface side. ,develop. Thereafter, the pattern film is peeled off, and the unexposed portion of the solder resist 10 (the portion covered with the pattern film) is removed by a remover, so that the terminals of the strip conductor pattern 2 are shown in FIG. 6C. The soldering surface of the portion 2A and the end surface 2a of the terminal portion 2A are exposed.

  After performing the solder resist formation step, as necessary, as shown in FIG. 6D, marks 20 such as identification characters and figures are printed on the surface of the solder resist 10 using symbol printing ink. The symbol printing process is performed.

  Thereafter, the excess portion of the copper-clad substrate 1 and the excessive portion of the copper plating layer and the solder resist formed on the copper-clad substrate are cut at both ends of the long hole 15 to adjust the outer shape of the printed wiring board. A cut finishing process is performed to obtain a printed wiring board 4 completed as shown in FIG.

  As in the present embodiment, the anticorrosion plating layer 12 covering the soldering surface and the end surface 2a of the terminal portion 2A of the conductor pattern 2 on the front surface side is a portion excluding the surface in contact with the substrate 1 of the conductor pattern 2 on the front surface side. And the anticorrosion plating layer 13 covering the end surface 3a of the terminal portion side end portion of the conductor pattern 3 on the back surface side is excluded from the surface in contact with the substrate 1 of the conductor pattern 3 on the back surface side. If it is provided so as to cover the entire part, it is possible to prevent the surface of the conductor pattern on the front surface side and the surface of the conductor pattern on the back surface side from being uneven. It is possible to prevent the electrical characteristics from deteriorating. In particular, when configuring a microstrip line, it is possible to eliminate the possibility of transmission loss due to the unevenness of the surface of the conductor pattern on both the front and back surfaces.

  In the above embodiment, the printed wiring board constituting the microstrip line is taken as an example. However, the present invention is not limited to the printed wiring board constituting the microstrip line, but the terminal portion of the conductor pattern on the surface side of the substrate. The present invention can be widely applied when it is necessary to dispose the end surface and the end surface of the terminal portion side end portion of the conductor pattern on the back surface side at the same position as the end surface of one end of the substrate.

  In the above embodiment, the width dimension of the ground conductor pattern 3 provided on the back surface side of the substrate is set equal to the width dimension of the substrate 1, but the width dimension of the ground conductor pattern 3 is smaller than the width dimension of the substrate 1. It may be set.

  In the above embodiment, the substrate 1 is an insulating substrate. However, the substrate 1 may be a laminated substrate having a structure in which a plurality of substrates on which conductor patterns are formed are laminated.

  In the above embodiment, the slit conductor pattern 2 is divided by forming the slit 2b in the portion near the end opposite to the terminal portion 2A to which the coaxial connector of the strip conductor pattern 2 is connected. The configuration on the end portion side opposite to the terminal portion 2A to which the coaxial connector of the strip conductor pattern 2 is connected is arbitrary.

  In the present invention, the end surface of the conductor pattern formed on the front surface side of the substrate and the end surface of the conductor pattern formed on the back surface side are located at the same position as the end surface of the substrate, as in the printed wiring board in which the microstrip line is configured. It can be widely used when it is necessary to arrange.

1 Substrate 1a End face of substrate 2 Strip conductor pattern (conductor pattern on the front side)
2A Terminal portion of strip conductor pattern 2a End surface of terminal portion 2A 2b Slit 201 Basic copper foil layer 202 Copper plating layer 3 Ground conductor pattern (conductor pattern on the back side)
3A Terminal portion side end portion of ground conductor pattern 3a End surface of terminal portion side end portion 3A 301 Basic copper foil layer 302 Copper plating layer 4 Printed wiring board 4 ′ Copper-clad substrate 5 Coaxial connector 5a Coaxial connector central conductor 6 Solder 10 Surface Side solder resist 10a Notch portion formed in solder resist 10 Back side solder resist 11a End surface of solder resist 11 12 Anticorrosion plating layer covering conductor pattern formed on front side of substrate 13 Formed on back side of substrate Anticorrosion plating layer covering the formed conductor pattern 15 Long hole 16 Copper plating layer 16a Exposed portion of copper plating layer 17 Etching resist film 17 'Etching resist 17a' Hole formed in etching resist 17b 'Slit 20 Mark for identification

Claims (6)

A terminal portion having a rectangular substrate, and a conductor pattern on the front surface side and the back surface side formed on the front surface and the back surface of the substrate, respectively, and the conductor pattern on the front surface side has a soldering surface to which an external conductor is soldered Is provided at a position near one end of the substrate, and the conductor pattern on the back surface side has a terminal portion side end facing the terminal portion of the conductor pattern on the front surface side at a position near the one end of the substrate, Of each part of the conductor pattern on the front surface side and the conductor pattern on the back surface side, the soldering surface and the end surface of the terminal part of the conductor pattern on the front surface side and the end surface of the terminal part side end portion of the conductor pattern on the back surface side are necessary. In a printed wiring board in which a solder resist layer is provided so as to cover a portion other than the exposed portion,
The end surface of the terminal portion of the conductor pattern on the front surface side and the end surface of the terminal portion side end portion of the conductor pattern on the back surface side are arranged at the same position as the end surface on one end side of the substrate, and the solder resist layer Without being covered by, and placed close to the end face of the substrate in between,
From the metal whose soldering surface and end surface of the terminal part of the conductor pattern on the surface side and the end surface of the terminal part side end part of the conductor pattern on the back surface side are less ionized than the metal forming each conductor pattern A printed wiring board characterized by being coated with an anticorrosion plating layer.   The conductor pattern on the front surface side is a strip conductor pattern constituting one of a pair of conductor patterns constituting a microstrip line, and the conductor pattern on the back surface side is an earth conductor pattern constituting the other of the pair of conductor patterns. Item 4. A printed wiring board according to item 1.   The printed wiring board according to claim 1, wherein the anticorrosion plating layer is formed of a gold plating layer applied to an outer surface of the conductor pattern via a nickel plating layer. The anticorrosion plating layer covering the soldering surface and the end surface of the terminal portion of the conductor pattern on the surface side is provided so as to cover the entire portion excluding the surface in contact with the substrate of the conductor pattern on the surface side,
The anticorrosion plating layer covering the end surface of the terminal portion side end portion of the conductor pattern on the back surface side is provided so as to cover the entire portion except the surface in contact with the substrate of the conductor pattern on the back surface side. Item 4. The printed wiring board according to item 1, 2 or 3. In the manufacturing method of the printed wiring board which manufactures the printed wiring board in any one of the Claims 1 thru / or 3 which give processing to the square copper-clad board in which the basic copper foil layer was formed in the front and back both sides of a substrate,
A drilling step of forming at least one hole in the copper-clad substrate including a long hole extending in the lateral direction of the copper-clad substrate through a portion near one end of the copper-clad substrate in the thickness direction;
A plating step of forming a copper plating layer covering the basic copper foil layers on both the front and back surfaces of the copper-clad substrate and the inner surfaces of the holes formed in the copper-clad substrate;
After applying an etching resist film on the copper plating layer formed on both the front and back surfaces of the copper-clad substrate, unnecessary portions of the etching resist film are removed to form a conductor pattern having a predetermined shape on both the front and back surfaces of the substrate. An etching resist forming step of forming an etching resist having a pattern necessary for performing;
Etching is performed on a copper-clad substrate having an etching resist formed on both front and back surfaces, and a conductor pattern on the surface side including a terminal portion having a soldering surface for soldering an external conductor is formed. A conductor pattern on the back side is formed on the surface of the substrate in a state of being arranged at the same position as the inner surface of the hole, and an end surface of the terminal portion side end portion is arranged at the same position as the inner surface of the elongated hole. Etching process to be formed,
An etching resist removing step for removing the etching resist;
Etching in a state in which the exposed portion including the soldering surface and end surface of the terminal portion of the conductor pattern on the surface side of the copper-clad substrate and the end surface of the end portion of the conductor pattern on the back surface side of the copper-clad substrate is exposed. A solder resist forming step of applying a solder resist to both the front and back surfaces of the copper-clad substrate from which the resist has been removed;
The soldering surface of the terminal portion of the conductor pattern on the surface side of the copper-clad substrate to which the solder resist is applied, the end surface of the terminal portion, and the end portion of the conductor pattern on the back surface exposed on the inner surface of the elongated hole An anticorrosion plating step of forming an anticorrosion plating layer so as to cover the end surface;
Cutting finish for adjusting the outer shape of the printed wiring board by cutting an excess portion of the copper-clad substrate and an excess portion of the copper plating layer and the solder resist formed on the copper-clad substrate at both ends of the long hole Process,
A method for manufacturing a printed wiring board, comprising: In the manufacturing method of the printed wiring board which manufactures the printed wiring board described in the above-mentioned claim 4 by processing a square copper-clad board in which the basic copper foil layer is formed on both the front and back sides of the board,
A drilling step of forming at least one hole in the copper-clad substrate including a long hole extending in the lateral direction of the copper-clad substrate through a portion near one end of the copper-clad substrate in the thickness direction;
A plating step of forming a copper plating layer covering the basic copper foil layers on both the front and back surfaces of the copper-clad substrate and the inner surfaces of the holes formed in the copper-clad substrate;
After applying an etching resist film on the copper plating layer formed on both the front and back surfaces of the copper-clad substrate, unnecessary portions of the etching resist film are removed to form a conductor pattern having a predetermined shape on both the front and back surfaces of the substrate. An etching resist forming step of forming an etching resist having a pattern necessary for performing;
Etching is performed on a copper-clad substrate having an etching resist formed on both front and back surfaces, and a conductor pattern on the surface side including a terminal portion having a soldering surface for soldering an external conductor is formed. A conductor pattern on the back side is formed on the surface of the substrate in a state of being arranged at the same position as the inner surface of the hole, and an end surface of the terminal portion side end portion is arranged at the same position as the inner surface of the elongated hole. Etching process to be formed,
An etching resist removing step for removing the etching resist;
An anticorrosion plating step of forming an anticorrosion plating layer so as to cover the exposed surface of the conductor pattern on the front surface side and the conductor pattern on the back surface side of the copper-clad substrate;
Soldering surfaces and end surfaces of the terminal portions of the conductor pattern on the surface side of the copper-clad substrate coated with at least the anti-corrosion plating layer, and end surfaces of the end portions of the conductor pattern on the back surface of the copper-clad substrate coated with the anti-corrosion plating layer And a solder resist forming step of applying a solder resist to both the front and back surfaces of the copper-clad substrate,
Cutting finish for adjusting the outer shape of the printed wiring board by cutting an excess portion of the copper-clad substrate and an excess portion of the copper plating layer and the solder resist formed on the copper-clad substrate at both ends of the long hole Process,
A method for manufacturing a printed wiring board, comprising:

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