JP2008166630A - Mounting member and manufacturing method thereof - Google Patents

Abstract

An object of the present invention is to achieve good solder wetting from the vicinity of an edge, to sufficiently form a fillet, and to ensure mounting strength.
A conductive mounting member 100 surface-mounted on a substrate having a conductor 310 or other counterpart member 300, a base material 110 having a main body 111 and a connecting portion 112 extending therefrom, and the base material A tin plating layer 120 formed on the surface, and the connecting portion is arranged to face the conductor of the mating member, and a side surface 112b-e extending from the periphery of the front end surface to the main body side. Inflection parts 113a, 114 that protrude outwardly at positions away from the peripheral edge of the front end surface on the side surface of the base material while extending away from the peripheral edge of the front end surface. By applying a tin plating to the surface and performing a reflow treatment, a tin plating layer having a thickened central portion due to the proximity of the tin plating is formed between the inflection portion on the side surface and the peripheral edge of the tip surface.
[Selection] Figure 1

Description

  The present invention belongs to the technical field of conductive mounting members that are surface-mounted on a substrate having a conductor or other counterpart member.

  Patent Document 1 discloses a surface mount type socket for an integrated circuit in which a solder creeping suppression portion such as a step or a recess is provided in the middle of a terminal piece of a contact spring. If it does in this way, when soldering a terminal piece to a circuit board, it can prevent solder from scooping up by a solder scooping suppression part, and does not impair the elasticity of a contact spring.

JP-A-6-13145

  As shown in FIG. 10, when tin plating is applied to the base material (B) of the contact (A), high-purity metal crystals may grow in a needle shape from the tin plating layer (C). This needle-like crystal is called a whisker and causes insulation failure in the contact (A). In order to prevent the occurrence of the whisker, the inventors applied tin plating to the base material (B) of the contactor (A), and then, as shown in FIG. 11, the base material (B) plated with tin. A reflow process is performed to remove internal stress and internal strain accumulated in the tin plating layer (C). The reflow process in this case is a process in which the surface of the base material once subjected to tin plating is heated to dissolve the tin plating layer, and the tin plating layer is re-formed through this reflow process.

  However, when the reflow treatment is performed, the tin plating is dissolved, and the dissolved tin plating is gathered by the surface tension. As shown in FIG. 11, due to this shift, the re-formed tin plating layer (C) has a substantially convex lens-shaped distribution in which the center rises and becomes thinner toward the periphery. Therefore, the tin plating layer (C) is formed thick near the center of the surface of the base material (B), but the tin plating layer (C) is thin near the edge. In this case, as shown in FIG. 12, the solder (D) is prevented from getting wet from the vicinity of the edge, the fillet is hardly formed, and the mounting strength of the mating member (E) to the conductor (F) is secured. I can't.

  The present invention has been made paying attention to such points, and the object is to provide an inflection portion that protrudes outward on the surface of the base material of the contactor or other mounting member. By blocking the melting of the plating that was melted during the reflow process and re-forming a tin plating layer with a sufficient thickness on the end face side of this inflection, it is possible to improve the solder wetting from the vicinity of the edge. The purpose is to sufficiently form the fillet and ensure the mounting strength.

  In order to achieve the above object, the mounting member of the present invention is a conductive mounting member that is surface-mounted on a substrate having a conductor or other counterpart member, and a base material having a main body and a connecting portion extending therefrom, A tin plating layer formed on the surface of the base material, and the connecting portion is arranged to face the conductor of the mating member, and a side surface extending from the periphery of the tip surface to the main body side And an inflection portion that protrudes outward from the peripheral edge of the front end surface on the side surface of the base material to the main body side and extends away from the peripheral edge of the front end surface. By performing the reflow process, a tin plating layer having a thickened central portion due to the proximity of the tin plating is formed between the inflection portion on the side surface and the peripheral edge of the tip surface.

  When tin plating is applied to the base material and reflow treatment is performed, the deviation of the molten tin plating is blocked by the inflection part, so that the deviation of the tin plating occurs between the inflection part on the side surface and the peripheral edge of the tip surface, Here, a tin plating layer having a thick central portion is re-formed. Therefore, compared with the case where there is no inflection part, a tin plating layer having a sufficient thickness is formed between the inflection part on the side surface and the peripheral edge of the tip surface. Becomes thick enough. As a result, the solder wets well from the vicinity of the peripheral edge of the front end surface, the fillet is sufficiently formed at the connection portion, and the mounting strength of the mounting member is ensured.

  In the mounting member of the present invention, the front end surface side of the side surface is a flat surface, a concave surface or a convex surface, and the inflection portion may be formed by increasing the curvature of the side surface from this surface toward the main body side.

  In the mounting member of the present invention, a groove may be provided on the side surface along a direction substantially parallel to the tip surface, and the edge on the tip surface side of the groove may be rounded, and the edge may be an inflection portion. .

  In the mounting member of the present invention, the base material is formed by press working, and the inflection portion may be provided on the side surface on the front end surface side that has become a convex surface due to sagging.

  In this way, a sufficiently thick tin plating layer is formed on the convex side surface on which surface tension is difficult to act, and the thickness of the tin plating layer is sufficiently thick even at the periphery of the tip surface. As a result, the solder wets well from the vicinity of the peripheral edge of the front end surface, the fillet is sufficiently formed at the connection portion, and the mounting strength of the mounting member is ensured.

  The mounting member of the present invention may be a contact of an electrical connector that is surface-mounted on a printed wiring board having conductors arranged in a pattern as a mating member.

  The mounting member manufacturing method of the present invention is a method for manufacturing a conductive mounting member that is surface-mounted on a substrate having a conductor or other counterpart member, and has a main body and a connection portion extending therefrom, A position that is disposed to face the conductor of the mating member and a side surface that extends from the periphery of the tip surface to the main body side, and that is away from the peripheral edge of the front surface on the side surface of the base material. In addition, the inflection portion that protrudes outward is subjected to a tin plating process in which the base material extending while keeping a distance from the peripheral edge of the front end surface is subjected to a reflow treatment, A reflow step of forming a tin plating layer having a thickened central portion due to the proximity of the tin plating between the inflection portion on the side surface and the peripheral edge of the tip surface.

  The mounting member of the present invention is provided with an inflection portion that protrudes outward on the side surface of the connecting portion of the base material, thereby blocking the deviation of the plating that has melted when reflow treatment is performed, than the inflection portion. Since the tin plating layer having a sufficient thickness is re-formed on the front end surface side, the solder wets well from the periphery of the front end surface, and the fillet is sufficiently formed in the connection portion. Mounting strength can be ensured.

  When the base material is molded by press working and the inflection part is provided on the side surface that has become convex due to sagging, a tin plating layer with a sufficient thickness is formed on the side surface that has a convex surface on which surface tension is unlikely to act. Solder wet-up from the vicinity of the surface periphery is performed satisfactorily, a fillet is sufficiently formed at the connection portion, and the mounting strength of the mounting member can be ensured.

  Embodiments of the present invention will be described below. The mounting member 100 of the first embodiment is a contact of the electrical connector EC shown in FIG. This electrical connector EC is mounted on the surface of a known printed wiring board having conductors 310 arranged in a pattern as a mating member 300 (see FIG. 3). The mounting member 100 is provided in an insulating housing 200 of the electrical connector EC. Hereinafter, a depth direction, a height direction, and a width direction that are orthogonal to each other will be defined and described. Referring to FIG. 1, the horizontal direction in the figure is the width direction, the vertical direction in the figure is the height direction, and the direction perpendicular to the drawing sheet is the depth direction.

  The mounting member 100 includes a conductive base material 110 and a tin plating layer 120 formed on the surface of the base material 110. As shown in FIG. 2, the base material 110 includes a main body 111 and a connection portion 112 extending from the main body 111 in the height direction. The main body 111 is provided with a contact portion (not shown), and this contact portion comes into contact with a contact of an electrical connector (not shown) as a connection partner.

  The connecting portion 112 includes a front end surface 112a facing substantially in the height direction, and side surfaces 112b, 112c, 112d, and 112e extending from the periphery of the front end surface 112a to the main body side. These side surfaces 112b, 112c, 112d, and 112e are appropriately curved so as to meet the purpose of use, and are subjected to a rounding process or the like. The front end surface 112 a is disposed to face the conductor 310 of the counterpart member 300. The base material 110 of this embodiment is formed by press working. Therefore, as shown in FIG. 2, the side surface 112 b on the near side in the depth direction of the base material 110 was a flat surface before pressing, but a convex surface is formed on the front end surface side due to sagging caused by press molding. .

  And the inflection part 113a is provided in the side surface 112b which the convex surface was made in this front end surface side. That is, the side surface 112b is provided with a groove 113 along the width direction which is one of the directions substantially parallel to the front end surface 112a, and the edge on the front end surface side of the groove 113 is rounded. It is part 113a. That is, the front end surface side of the side surface 112b is convex, and the inflection portion 113a is formed by increasing the curvature of the side surface 112b from this surface toward the main body side. As a result, the inflection portion 113a that protrudes outward from the peripheral edge of the front end surface 112a on the side surface 112b of the base material 110 extends toward the main body side while keeping a distance from the peripheral edge of the front end surface 112a. .

  As shown in FIG. 2, the tin plating layer 120 is applied to the surface of the base material 110 by a known plating method. In the case of this embodiment, pure tin plating is performed by plating with tin having a purity of 100%. However, the tin may be plated with a tin alloy having a purity of less than 100% and containing other elements. Then, after the tin plating is applied to the base material 110, the reflow treatment is performed, so that the central portion becomes thicker due to the deviation of the tin plating between the inflection portion 113a on the side surface 112b and the peripheral edge of the front end surface 112a. A convex lens-shaped tin plating layer 121 is formed. This reflow process is a process in which the surface of the base material 110 once subjected to tin plating is heated to dissolve the tin plating layer, and the temperature of the tin plating layer 121 as described above is lowered after this process. Is formed.

  FIG. 4 is a photograph corresponding to FIG. 2 showing an example of the first embodiment. In the case of this embodiment, the depth of the connecting portion (the outer dimension in the horizontal direction in FIG. 4) is about 0.15 mm, the height (the outer dimension in the vertical direction in FIG. 4) is about 0.2 mm, and the depth of the groove is about 0.03 mm. Moreover, the thickness of the tin plating layer before the reflow treatment is about 2 μm. FIG. 9 shows a comparative example, in which the depth and height of the connecting portion and the thickness of the tin plating layer before the reflow treatment are set to substantially the same dimensions as in the example.

  Therefore, in the case of the mounting member 100 of the above embodiment, when the base material 110 is tin plated and subjected to reflow processing, the melted tin plating is blocked by the inflection portion 113a. A shift of the tin plating occurs between 113a and the periphery of the tip surface 112a, and a substantially convex lens-shaped tin plating layer 121 having a thick central portion is re-formed here. Therefore, compared to the case where there is no inflection portion as shown in FIG. 9, a tin plating layer 121 having a sufficient thickness is formed between the inflection portion 113a on the side surface 112b and the peripheral edge of the front end surface 112a, and the front end surface Even at the periphery of 112a, the thickness of the tin plating layer 121 becomes sufficiently thick (see FIGS. 2 and 4). As a result, as shown in FIG. 3, the solder 400 is satisfactorily wetted from the vicinity of the peripheral edge of the front end surface 112 a, the fillet is sufficiently formed in the connection portion 112, and the mounting strength of the mounting member 100 is ensured. .

  The present invention does not limit the manufacturing method of the base material of the mounting member. However, in the mounting member 100 of the above-described embodiment, the base material 110 is formed by press working, and the inflection portion 113a is provided on the side surface 112b on the front end surface side that has become convex due to sagging. In this way, a substantially convex lens-shaped tin plating layer 121 having a sufficient thickness is formed on the side surface 112b, which is a convex surface on which surface tension is difficult to act. Thickness will be thick enough. As a result, the solder 400 is satisfactorily wetted from the vicinity of the peripheral edge of the front end surface 112a, a sufficient fillet is formed in the connection portion 112, and the mounting strength of the mounting member 100 is ensured.

  Hereinafter, other embodiments will be described. In the mounting member 100 of these embodiments, the same components as those of the mounting member 100 of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. FIG. 5 shows a mounting member 100 according to the second embodiment of the present invention. In the mounting member 100 of the first embodiment, the front end surfaces of the side surfaces 112b and 112c are convex or flat, but in the mounting member 100 of the second embodiment, the side surface 112b on the near side in the depth direction and the side surface 112c on the back side are The tip surface side is a flat surface. And the groove | channel is not provided, but the back surface 112f on the opposite side to the front end surface 112a is formed in the convex surface instead, and, thereby, the side surfaces 112b and 112c toward the main body side from the surface of the front end surface side which is a plane. The inflection portion 114 is formed by increasing the curvature. Thus, the inflection 114 that protrudes outward from the peripheral edge of the front end surface 112a on the side surfaces 112b and 112c of the base material 110 toward the main body is along a direction substantially parallel to the front end surface 112a. Is provided.

  Therefore, in the case of the mounting member 100 according to the second embodiment, when the base material 110 is plated with tin and subjected to reflow processing, the melted tin plating is blocked by the inflection portion 114, so the side surfaces 112 b and 112 c A tin plating shift occurs between the inflection portion 114 and the peripheral edge of the tip surface 112a, and a substantially convex lens-shaped tin plating layer 121 having a thick central portion is re-formed here. Therefore, compared to the case where there is no inflection part, a tin plating layer 121 having a sufficient thickness is formed between the inflection part 114 on the side surfaces 112b and 112c and the periphery of the tip surface 112a. Even if it exists, the thickness of the tin plating layer 121 becomes sufficiently thick (see FIG. 5). As a result, the solder wets well from the vicinity of the peripheral edge of the front end surface 112a, the fillet is sufficiently formed in the connection portion 112, and the mounting strength of the mounting member 100 is ensured.

  FIG. 6 shows a mounting member 100 according to the third embodiment of the present invention. In the mounting member 100 of the first embodiment, the front end surfaces of the side surfaces 112b and 112c are convex or flat, but in the mounting member 100 of the third embodiment, the side surface 112b on the near side in the depth direction and the side surface 112c on the back side are The tip surface side is a flat surface. The side surfaces 112b and 112c are respectively provided with grooves 113 along a direction substantially parallel to the front end surface 112a, and the edges on the front end surface side of the grooves 113 are rounded, and these edges are inflected portions 113a. It has become. That is, the front end surfaces of the side surfaces 112b and 112c are flat, and the inflection portion 113a is formed by increasing the curvature of the side surfaces 112b and 112c from this surface toward the main body side. As a result, the inflection portion 113a that protrudes outward from the periphery of the front end surface 112a on the side surfaces 112b and 112c of the base material 110 toward the main body side is along a direction substantially parallel to the front end surface 112a. Is provided.

  Therefore, in the case of the mounting member 100 of the third embodiment, when the base material 110 is plated with tin and subjected to reflow processing, the melted tin plating is blocked by the inflection portion 113a, so the side surfaces 112b and 112c A tin plating shift occurs between the inflection portion 113a and the peripheral edge of the front end surface 112a, and a substantially convex lens-shaped tin plating layer 121 having a thick central portion is re-formed here. Therefore, compared with the case where there is no inflection part, a tin plating layer 121 having a sufficient thickness is formed between the inflection part 113a on the side surfaces 112b and 112c and the peripheral edge of the front end face 112a. Even if it exists, the thickness of the tin plating layer 121 becomes thick enough (refer FIG. 6). As a result, the solder wets well from the vicinity of the peripheral edge of the front end surface 112a, the fillet is sufficiently formed in the connection portion 112, and the mounting strength of the mounting member 100 is ensured.

  FIG. 7 shows a mounting member 100 according to the fourth embodiment of the present invention. In the mounting member 100 of the first embodiment, the front end surfaces of the side surfaces 112b and 112c are convex or flat, but in the mounting member 100 of the fourth embodiment, the side surface 112b on the near side in the depth direction and the side surface 112c on the back side are The tip surface side is all concave. And the groove | channel is not provided, but the inflection part 114 is formed by the curvature of the side surfaces 112b and 112c increasing toward the main body side from the surface by the side of the front end surface which is a concave surface. Thus, the inflection 114 that protrudes outward from the peripheral edge of the front end surface 112a on the side surfaces 112b and 112c of the base material 110 toward the main body is along a direction substantially parallel to the front end surface 112a. Is provided.

  Therefore, in the case of the mounting member 100 of the fourth embodiment, when the base material 110 is plated with tin and subjected to reflow processing, the melted tin plating is blocked by the inflection portion 114, so that the side surfaces 112b and 112c A tin plating shift occurs between the inflection portion 114 and the peripheral edge of the tip surface 112a, and a substantially convex lens-shaped tin plating layer 121 having a thick central portion is re-formed here. Therefore, compared to the case where there is no inflection part, a tin plating layer 121 having a sufficient thickness is formed between the inflection part 114 on the side surfaces 112b and 112c and the periphery of the tip surface 112a. Even if it exists, the thickness of the tin plating layer 121 becomes sufficiently thick (see FIG. 7). As a result, the solder wets well from the vicinity of the peripheral edge of the front end surface 112a, the fillet is sufficiently formed in the connection portion 112, and the mounting strength of the mounting member 100 is ensured.

  FIG. 8 shows a mounting member 100 according to the fifth embodiment of the present invention. This mounting member 100 is a modification of the mounting member 100 of the fourth embodiment. The mounting member 100 of the fifth embodiment has a larger angle formed by the front end surface 112a and the side surfaces 112b and 112c on the front end surface side than the mounting member 100 of the fourth embodiment, and the curvature of the inflection portion 114 is larger. large. The operation and effect are the same as those of the mounting member 100 of the fourth embodiment.

  By the description of the above embodiment, the method for manufacturing the mounting member of the present invention has been sufficiently disclosed. That is, the manufacturing method is a method for manufacturing a conductive mounting member 100 that is surface-mounted on a substrate having a conductor 310 or other counterpart member 300, and includes a tin plating step and a subsequent reflow step. . This tin plating process has a main body 111 and a connecting portion 112 extending therefrom, and the connecting portion 112 is disposed so as to face the conductor 310 of the counterpart member 300, and the tip surface 112a. Inflection part 113a which is provided with side surfaces 112b, 112c, 112d, and 112e extending from the peripheral edge to the main body side and is convex outward at a position away from the peripheral edge of the front end surface on the side surfaces 112b and 112c of base material 110 toward the main body side. , 114 is a step of performing tin plating on the base material 110 provided along a direction substantially parallel to the front end surface 112a. Further, in the reflow process to be performed next, the tin plated base material 110 is subjected to a reflow process, and the tin plating is formed between the inflection portions 113a and 114 on the side surfaces 112b and 112c and the peripheral edge of the front end surface 112a. This is a step of forming a tin plating layer 121 whose central portion is thickened by the shift.

  The present invention includes an embodiment in which the features of the above embodiments are combined. Moreover, the above embodiment and Example only showed some examples of the mounting member of this invention, and its manufacturing method. Therefore, the mounting member of the present invention and the manufacturing method thereof are not limitedly interpreted by the description, dimensions, and the like of these embodiments and examples. The mounting member of this invention should just be surface-mounted to the board | substrate which has a conductor, or another other party member. The board includes a plate-like member other than the printed wiring board, and the mating member includes a three-dimensional member such as MID. In addition to the contacts, the mounting member includes a reinforcing tab for reinforcing the connection strength by mounting, for example, an electrical connector or other electronic component on the conductor of the counterpart member. Moreover, in the above embodiment, the inflection part was provided in the side surface suitable for the depth direction, but you may provide an inflection part in another side surface. Therefore, the inflection part and the groove may be provided not only in the width direction but also in the depth direction or other directions. In addition, the inflection part and the groove may be provided not only along the direction substantially parallel to the tip surface but also along other directions, and may be extended with a distance from the periphery of the tip surface. Further, the inflection part and the groove may extend linearly as shown in the embodiment, or may be bent and extended. The inflection part may be formed by the edge on the front end face side of the groove, or the inflection part may be formed by increasing the curvature of the side face from the front end face side toward the main body without providing the groove. Good. The shape of the inflection part and the groove may be different on a plurality of side surfaces of one mounting member. As shown in the embodiment, the side surface does not have to be plural, and may be formed in a series in the circumferential direction.

It is a front view which shows the electrical connector provided with the mounting member of 1st Embodiment. It is the figure which expanded the end surface when the mounting member of FIG. 1 is cut in the II-II line. It is the figure which mounted the mounting member of 1st Embodiment in the other party member, and expanded the end surface when it cuts in the line equivalent to the II-II line of FIG. It is a photograph which shows the end surface equivalent to FIG. 2 in the Example of 1st Embodiment. It is an enlarged end view equivalent to FIG. 2 in the mounting member of 2nd Embodiment. It is an enlarged end view equivalent to FIG. 2 in the mounting member of 3rd Embodiment. It is an enlarged end view equivalent to FIG. 2 in the mounting member of 4th Embodiment. It is an enlarged end view equivalent to FIG. 2 in the mounting member of 5th Embodiment. It is a photograph which shows the end surface equivalent to FIG. 2 in the comparative example which does not provide the groove | channel. It is an end elevation before reflow processing of the conventional contact. It is an end view after the reflow process of the conventional contactor. It is an end view when the conventional contact is mounted on the mating member.

Explanation of symbols

EC electrical connector 100 Mounting member (contact)
DESCRIPTION OF SYMBOLS 110 Base material 111 Main body 112 Connection part 112a Front end surface 112b Side surface 112c Side surface 112d Side surface 112e Side surface 113 Groove 113a Inflection part 114 Inflection part 120 Tin plating layer 121 Tin plating layer 300 Opposite side member 310 Conductor 400 Solder A Contact B Mother Material C Tin plating layer D Solder E Mating member F Conductor

Claims (6)

A conductive mounting member that is surface-mounted on a substrate having a conductor or other counterpart member,
A base material having a main body and a connecting portion extending therefrom, and a tin plating layer formed on the surface of the base material;
The connecting portion includes a front end surface to be disposed facing the conductor of the counterpart member, and a side surface extending from the periphery of the front end surface to the main body side,
In a position away from the peripheral edge of the front end surface on the side surface of the base material toward the main body side, an inflection portion that protrudes outward extends while keeping a distance from the peripheral edge of the front end surface,
A mounting member in which a tin plating layer having a thickened central portion is formed between the inflection portion on the side surface and the peripheral edge of the tip surface by applying a tin plating to the base material, and by the deviation of the tin plating.   The mounting member according to claim 1, wherein the front end surface side of the side surface is a flat surface, a concave surface, or a convex surface, and the inflection portion is formed by increasing the curvature of the side surface from this surface toward the main body side.   The mounting according to claim 1 or 2, wherein a groove is provided on a side surface along a direction substantially parallel to the tip surface, and an edge on the tip surface side of the groove is rounded, and the edge is a curved portion. Element.   The mounting member according to any one of claims 1 to 3, wherein the base material is formed by press working, and an inflection portion is provided on a side surface on a front end surface side that has become a convex surface by sagging.   The mounting member according to any one of claims 1 to 4, wherein the printed wiring board having conductors arranged in a pattern is used as a mating member and is a contact of an electrical connector that is surface-mounted on the mating member. A method for manufacturing a conductive mounting member to be surface-mounted on a substrate having a conductor or other counterpart member,
A main body and a connection portion extending from the main body, the connection portion including a front end surface to be disposed to face the conductor of the counterpart member, and a side surface extending from the periphery of the front end surface to the main body side; A tin plating step of applying a tin plating to a base material extending in a position away from the peripheral edge of the front end surface at a position away from the peripheral edge of the front end surface on the side of the main body side,
A mounting member comprising: a reflow process for performing a reflow process on the tinned base material and forming a tin plating layer having a thickened central portion due to the proximity of the tin plating between the inflection portion on the side surface and the peripheral edge of the tip surface Manufacturing method.