JP2012033732A - Method for manufacturing terminal connection part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a fillet-shaped solder connection part on the lower surface of a circuit board after filling solder in a through hole by melting a solder chip and pouring the solder to the lower surface side from the upper surface side of the circuit board.SOLUTION: In the method for manufacturing a terminal connection part 30, a solder chip 40 is placed on a cream solder 14 applied on an upper surface 11 of a circuit board 10 to perform reflow, and thereby connecting a terminal 20 to a pair of lands 13B connected to an inner wall 13A and the both end parts of the inner wall 13A constituting a through hole 13 formed in the circuit board 10. The cream solder 14 is applied on the upper surface 11 of the circuit board 10 so as to cross an insertion path of the terminal 20 in the through hole 13 in a state of covering a part of an end opening of the through hole 13.

Description

  The present invention relates to a method for manufacturing a terminal connection portion using a solder chip.

  Conventionally, as a technique for performing reflow soldering using a solder chip, those described in the following Patent Documents 1 to 3 are known. As a mounting method by reflow soldering, cream solder is generally printed on a land formed on the upper surface of a circuit board, and a mounting component is placed on the cream solder and passed through a reflow furnace. Here, there are various types of mounting parts, from small sizes such as chip capacitors and chip resistors to large sizes such as crystal resonators and connectors. When the size of the mounted component increases, the amount of solder required for connection increases accordingly, so that a lot of cream solder needs to be applied to the upper surface of the circuit board. However, the amount of cream solder that can be applied by printing is limited, and a sufficient amount of cream solder for connection may not be applied by printing alone. Therefore, a solder chip is placed on a portion where the solder is insufficient to compensate for the amount of solder.

JP 2006-261573 A JP 2001-237535 A JP 2003-324271 A

  By the way, in forming a terminal connection portion formed by passing a terminal through a through hole and connecting with solder, it is necessary to connect the terminal to an inner wall constituting the through hole and a pair of upper and lower lands connected to the inner wall. It is necessary to form fillet-like solder connection portions on both upper and lower sides of the substrate. As a general soldering method, there is a method using a flow solder bath. However, this method has a disadvantage in that it is necessary to provide a mounting prohibited area on the substrate and the number of processes is increased. Therefore, solder connection using a reflow furnace is often performed in a state in which the terminal is passed through the through hole, but it is necessary to print cream solder on the through hole portion. However, if cream solder is printed inside the through-hole, there is a concern that the solder may fall off, so if it is applied only to the top surface of the circuit board without contacting the terminals, the flux contained in the cream solder will adhere to the terminals. I can't. For this reason, when a terminal having poor wettability with respect to solder is used, the wettability of the terminal cannot be improved. Further, since the solder chip does not contain flux, it is difficult to melt the solder chip and flow the melted solder as it is into the through hole.

  The present invention has been completed based on the above circumstances, and by filling the through hole with solder by melting the solder chip and pouring the solder from the upper surface side to the lower surface side of the circuit board, It is an object to form fillet-like solder connection portions on both upper and lower sides of a circuit board.

  According to the present invention, a solder chip is placed on a cream solder applied to the upper surface of a circuit board and reflow is performed, whereby a pair of inner walls constituting a through hole formed in the circuit board and both ends of the inner wall are connected. A method of manufacturing a terminal connection portion in which a terminal is connected to a land of a circuit board in a state in which cream solder covers a part of an end opening of a through hole so as to intersect a terminal insertion path in the through hole It is characterized in that it is applied to the upper surface.

  According to such a manufacturing method, the cream solder containing flux can be brought into contact with the terminal when the terminal is inserted into the through hole. For this reason, when reflow is performed and the solder chip is melted, the flux wets and spreads on the terminal, and the melted solder easily flows along the terminal from the upper surface side to the lower surface side. In addition, since a sufficient amount of solder required for connection can be supplied by the solder chip, the fillet-like solder connection portions can be formed on both the upper and lower sides of the circuit board after filling the solder in the through hole. .

The following configuration is preferable as an embodiment of the present invention.
The terminal is configured to include both the exposed surface where the metal plate is exposed and the plated surface where the metal plate is plated by punching a plated metal plate with a metal plate different from the metal plate on the surface of the metal plate. It is preferable to insert the terminal into the through hole so that the cream solder comes into contact with the surface of the exposed surface and the plated surface that has poor wettability with respect to the solder.

  In this way, the flux contained in the cream solder can be brought into contact with the surface having poor wettability, so that the solder is applied from the upper surface side to the lower surface side of the circuit board after improving the wettability of this surface. Can be poured. On the other hand, on the surface having better wettability with respect to the solder, the solder can be poured from the upper surface side to the lower surface side of the circuit board even when there is no flux. Therefore, solder can be efficiently poured into the through hole from the upper surface side of the circuit board.

  The plated metal plate is a nickel-plated copper plate having a nickel plate on the surface of the copper plate, and it is preferable to insert the terminal into the through hole so that the cream solder contacts the plated surface on which the nickel plating has been applied.

  In general, since lead-free solder is difficult to wet with nickel, it is necessary to perform soldering using a flux. In that respect, according to the above method, since the cream solder comes into contact with the plated surface on which nickel plating is applied, even when lead-free solder is used, the solder can be poured into the through hole from the plated surface. .

Both the land and the solder chip may have a ring shape, and reflow may be performed in a state where cream solder is sandwiched between the land and the solder chip.
If it does in this way, the circumference | surroundings of a terminal can be enclosed over a perimeter with a solder chip. Therefore, it becomes easy to pour solder into the through hole.

A pair of cream solders may be applied to both sides of the terminal.
If it does in this way, a pair of cream solder can be made to contact a terminal, respectively. Therefore, it becomes easy to supply flux to the terminal.

  According to the present invention, the solder chip is melted and the solder is poured from the upper surface side to the lower surface side of the circuit board, so that the through hole is filled with the solder and the fillet-like solder connection portion is formed on the lower surface of the circuit board. can do.

Top view of the through hole formed in the circuit board as seen from above The top view which shows the state which applied a pair of cream solder to the upper surface of the circuit board of FIG. FIG. 2 is a partially cutaway plan view of the terminal inserted into the through hole in FIG. 2 as viewed from above. The top view which shows the state which mounted the solder chip on the cream solder of FIG. AA line sectional view in FIG. BB sectional view in FIG. Sectional drawing which shows the state in which the terminal connection part was formed by letting the circuit board of FIG. 6 pass through a reflow furnace. Perspective view of solder chip

<Embodiment>
An embodiment of the present invention will be described with reference to the drawings of FIGS. The circuit board 10 according to the present embodiment is a double-sided board in which copper foils are attached to the upper and lower surfaces of a plate-like base material made of an insulating synthetic resin material. As shown in FIG. 5, the circuit board 10 has a through hole 13 penetrating between the upper surface 11 and the lower surface 12 of the circuit board 10 in the vertical direction (direction perpendicular to the paper surface in FIG. 1). The through hole 13 includes an inner wall 13A and a pair of lands 13B that are connected to both upper and lower ends of the inner wall 13A. Further, as shown in FIG. 1, the through hole 13 has a circular shape, and both the lands 13B have the same shape and a ring shape.

  The terminal 20 has a columnar shape with a substantially square cross section, and comprises a copper plate 21 and a nickel plating 23 applied to the surface of the copper plate 21 as shown in FIG. As shown in FIG. 3, the left and right side surfaces of the copper plate 21 are exposed surfaces 22 from which the copper plate 21 is exposed. On the other hand, the nickel plating 23 is formed on both upper and lower side surfaces of the copper plate 21 in the figure, and the surface of the nickel plating 23 is a plating surface 24. That is, the terminal 20 has a pair of exposed surfaces 22 and a nickel plating 23 where the copper plate 21 is exposed by punching out the nickel plated copper plate using a nickel plated copper plate whose surface is nickel plated as a base material. And a pair of plated surfaces 24.

  As shown in FIG. 7, the terminal 20 is connected to the circuit board 10 by a terminal connection portion 30. The terminal connection part 30 has a solder connection part 31 made of lead-free solder. The solder connection portion 31 includes a fillet-shaped first connection portion 31A formed on the upper surface 11 side of the circuit board 10, a second connection portion 31B filled in the through hole 13, and a lower surface 12 side of the circuit substrate 10. It is comprised from the formed fillet-shaped 3rd connection part 31C. The terminal 20 is connected to the inner wall 13 </ b> A and both lands 13 </ b> B through the solder connection portion 31 so as to be conductive.

  Next, the configuration of the terminal connection unit 30 will be described in detail. As shown in FIG. 2, cream solder 14 made of lead-free solder is applied to the upper surface 11 of the circuit board 10 by a screen printing machine (not shown). As shown in FIG. 2, a pair of cream solders 14 are arranged in a substantially square shape so as to face each other. The opposing sides 14 </ b> A of both cream solders 14 are arranged in a state of protruding toward the through hole 13 so as to cover a part of the end opening of the through hole 13. Both opposing sides 14A are arranged in parallel to each other with a predetermined interval. For this reason, the front-end | tip of the terminal 20 can be penetrated between 14A of both opposing sides.

  The length of the opposing side 14A is set to be substantially the same as the outer diameter of the land 13B, and the side adjacent to the opposing side 14A (the side arranged perpendicular to the opposing side 14A and facing the opposite side 14A). The length of the side that is continuous with the side 14A is set to be equal to or more than ½ of the outer diameter of the land 13B. For example, the length of the opposing side 14A is 2.4 mm, the length of the side adjacent to the opposing side 14A is 1.5 mm, the outer diameter of the land 13B is φ2.4 mm, and the inner diameter of the land 13B is φ1.4 mm. Also good. Therefore, the land 13B is in a state where all the areas except for the area sandwiched between the opposing sides 14A are covered with the cream solders 14. For this reason, the solder produced by melting the cream solder 14 at the time of reflow flows into both lands 13B by the action of surface tension.

  The overlapping region 15 where the through hole 13 and the cream solder 14 overlap in the vertical direction is set to be ½ or less of the area of the end opening of the through hole 13. For this reason, the entire end opening of the through hole 13 is not closed by the overlapping region 15. The space between the gaps 16 formed between the overlapping regions 15 is set to be smaller than the distance between the plated surfaces 24 of the terminal 20. For example, the interval between the gaps 16 may be 0.6 mm, and the distance between the two plating surfaces 24 may be 0.64 mm. Further, the overlapping regions 15 are arranged so as to overlap with the insertion path of the terminal 20 inserted into the through hole 13. For this reason, as shown in FIG. 3, when the terminals 20 are inserted into the through holes 13 so that the alignment direction of the plating surfaces 24 and the alignment direction of the opposing sides 14 </ b> A are aligned, The plated surface 24 comes into contact with the cream solder 14.

  When the cream solder 14 is melted by reflow, the flux contained in the cream solder 14 spreads on the plated surface 24 and the melted solder flows along the plated surface 24 from the upper surface 11 side to the lower surface 12 side of the circuit board 10. Become. On the other hand, although the cream solder 14 is not in direct contact with both the exposed surfaces 22 of the terminals 20, the solder circulates from both the plated surfaces 24 to both the exposed surfaces 22, and this solder travels along the both exposed surfaces 22 to form a circuit board. 10 flows from the upper surface 11 side to the lower surface 12 side. Therefore, solder can be poured from the upper surface 11 side to the lower surface 12 side of the circuit board 10 by reflow.

  By the way, in this embodiment, all the solder necessary for forming the second connection part 31B filled in the through hole 13 and the both connection parts 31A and 31C located on both upper and lower sides of the circuit board 10 is used. Therefore, it is difficult to supply all of these solders with the cream solder 14. Therefore, in this embodiment, a solder chip 40 made of lead-free solder is placed on the upper surface of the cream solder 14, and a sufficient amount of solder is supplied by the solder chip 40. As shown in FIG. 8, the solder chip 40 has a ring shape and has flat surfaces 41 on both upper and lower sides. Both flat surfaces 41 are arranged substantially in parallel. As a result, the upper flat surface 41 of the solder chip 40 is adsorbed by a component mounting machine (not shown), the solder chip 40 is conveyed onto the through hole 13, and the lower flat surface 41 is placed on the cream solder 14. It is possible.

  As shown in FIG. 4, the solder chip 40 is mounted substantially coaxially with the land 13B. The outer diameter dimension of the solder chip 40 is larger than the outer diameter dimension of the land 13B. Further, the inner diameter of the solder chip 40 is substantially equal to the inner diameter of the land 13 </ b> B and larger than the cross-sectional shape of the terminal 20. For this reason, when the solder chip 40 is placed on the cream solder 14, the cream solder 14 is sandwiched between the land 13B and the solder chip 40 as shown in FIG. For example, the outer diameter of the solder chip 40 may be φ3.5 mm, the inner diameter of the solder chip 40 may be φ1.5 mm, and the thickness of the solder chip 40 may be 0.5 to 1.0 mm.

  Since the solder chip 40 does not contain a flux, the wettability of the solder when the solder chip 40 is melted is ensured by the flux contained in the cream solder 14. The content ratio of the flux is desirably 11 to 15 vol% or more with respect to the total amount of solder. The total amount of solder is the amount of solder in which the solder in the cream solder 14 and the solder of the solder chip 40 are combined. When the solder chip 40 is melted, the flux supplied from the cream solder 14 flows through the terminal 20 and flows into the through hole 13, and a part of the solder flows further downward from the through hole 13 to the third connection portion 31C. Become. 7 is formed by the solder in the cream solder 14 and the solder of the solder chip 40.

  The present embodiment is configured as described above, and a method for manufacturing the terminal connection portion 30 will be described. First, a pair of cream solders 14 shown in FIG. 2 is applied onto the lands 13B by printing cream solder on the upper surface 11 of the circuit board 10 shown in FIG. 1 with a screen printer. Next, the terminal 20 is inserted into the through hole 13. At this time, both the plating surfaces 24 of the terminals 20 are in contact with both opposing sides 14A, and both the plating surfaces 24 are in contact with the cream solder 14 in both overlapping regions 15 as shown in FIG. Subsequently, the upper flat surface 41 of the solder chip 40 is sucked and conveyed onto the through hole 13 by the component mounter, and the lower flat surface 41 is placed on the cream solder 14.

  Next, the circuit board 10 is passed through a reflow furnace (not shown) to perform reflow soldering. The solder chip 40 and the cream solder 14 are melted by the heat of the reflow furnace, and the flux contained in the cream solder 14 spreads wet on the plating surface 24. On the other hand, the exposed surface 22 is the surface from which the copper plate 21 is exposed, and originally has good wettability with solder, so that the wettability necessary for soldering can be ensured even in the absence of flux. Therefore, the solder melted by reflow is filled into the through hole 13 through the terminal 20 to form the second connection portion 31B, and further, the fillet-like third connection portion 31C is formed below the through hole 13. . The remaining solder remains above the through-hole 13 to form a fillet-like first connection portion 31A.

  As described above, in this embodiment, since the pair of cream solders 14 is applied to the upper surface 11 side of the circuit board 10 and the solder chip 40 is placed on both the cream solders 14, the upper surface of the circuit board 10 is obtained by reflow soldering. Solder is poured from the 11 side to the lower surface 12 side, and a solder connection portion 31 formed by forming a pair of fillet-like solders on both the upper and lower sides of the through hole 13 while filling the through hole 13 with the solder can be formed.

  Here, although the plating surface 24 is a surface plated with nickel and does not have good wettability with lead-free solder, the cream solder 14 containing flux is in contact with the plating surface 24, and thus the plating surface 24. Can improve the wettability with respect to solder. Therefore, even when lead-free solder is used, the solder connection portion 31 can be formed by pouring solder from the upper surface 11 side to the lower surface 12 side of the circuit board 10.

  Further, since both the land 13B and the solder chip 40 have a ring shape, solder can be poured into the through hole 13 from around the terminal 20. Therefore, solder can be poured efficiently into the through hole 13. Further, since the pair of cream solders 14 is applied on both sides of the terminal 20, it becomes easy to supply the flux to both the plating surfaces 24 of the terminal 20.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) Although the pair of cream solders 14 is applied to both sides of the terminal 20 in the above embodiment, one cream solder 14 may be applied to one side of the terminal 20 according to the present invention.

  (2) Although the pair of cream solders 14 is applied to both sides sandwiching the terminal 20 in the above embodiment, according to the present invention, in addition to both sides sandwiching the terminal 20, both sides sandwiching the terminal 20 from the vertical direction, You may apply | coat the cream solder 14 in the state divided | segmented into four places collectively.

  (3) Although the above embodiment illustrates the terminal 20 having a columnar shape with a substantially square cross section, according to the present invention, a round bar-shaped terminal may be used. In this case, the cream solder may be applied in a ring shape so that the cream solder contacts the entire circumference of the terminal.

  (4) Although the terminal 20 is formed using a nickel-plated copper plate as a base material in the above embodiment, according to the present invention, the terminal may be formed using a copper plate that is not plated.

  (5) Although the ring-shaped solder chip 40 is used in the above embodiment, the shape of the solder chip is not limited according to the present invention. For example, a spherical solder chip may be placed on the cream solder 14.

  (6) Although lead-free solder is used in the above embodiment, lead-containing solder may be used according to the present invention.

DESCRIPTION OF SYMBOLS 10 ... Circuit board 11 ... Upper surface 12 ... Lower surface 13 ... Through hole 13A ... Inner wall 13B ... Land 14 ... Cream solder 20 ... Terminal 21 ... Copper plate (metal plate)
DESCRIPTION OF SYMBOLS 22 ... Exposed surface 23 ... Nickel plating 24 ... Plated surface 30 ... Terminal connection part 31 ... Solder connection part 40 ... Solder chip 41 ... Flat surface

Claims (5)

By placing the solder chip on the cream solder applied to the upper surface of the circuit board and performing reflow, the inner wall constituting the through hole formed in the circuit board and a pair of lands connected to both ends of the inner wall are formed. A method of manufacturing a terminal connection portion to which a terminal is connected,
The terminal connection is characterized in that the cream solder is applied to the upper surface of the circuit board in a state of covering a part of the end opening of the through hole so as to intersect the insertion path of the terminal in the through hole. Part manufacturing method. The terminal is formed by punching a plated metal plate having a metal plate plated with a different metal on the surface of the metal plate, so that both the exposed surface on which the metal plate is exposed and the plated surface on which the plating is applied are provided. Comprising
2. The terminal connection part according to claim 1, wherein the terminal is inserted into the through hole so that the cream solder comes into contact with a surface of the exposed surface and the plated surface that has poor wettability with respect to solder. Manufacturing method.   The plated metal plate is a nickel-plated copper plate having a nickel plate applied to the surface of the copper plate, and the terminals are placed in the through holes so that the cream solder contacts the plated surface on which the nickel plating has been applied. The method for manufacturing a terminal connection part according to claim 2, wherein the terminal connection part is inserted.   The land and the solder chip are both in a ring shape, and reflow is performed in a state where the cream solder is sandwiched between the land and the solder chip. The manufacturing method of the terminal connection part as described in any one.   5. The method of manufacturing a terminal connecting portion according to claim 1, wherein a pair of the cream solder is applied to both sides of the terminal.

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