JP2010267672A - Flux transferring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flux transferring device, which does not have variance in application amount of flux transferred onto a substrate among transfer pins and which can maintain high reliability for a long period, at low costs. <P>SOLUTION: The flux transferring device 1 has a plurality of transfer pins 3 held in a predetermined array through an elastic pressing portion 2 so as to be moved up and down, and each of the transfer pins 3 protrudes downward through a guide hole. Each of the transfer pins 3 is provided with a groove 3c from the tip to the root side of each of the transfer pins 3 at a position which is far by a predetermined amount, and the groove 3c extends over the entire circumference of each of the transfer pins 3. After tip portions 3a of the respective transfer pins 3 are dipped in flux 4 in a flux tray 5 to stick flux 4a on the tip portions 3a, the tips of the respective transfer pins 3 are brought into contact with corresponding lands 7 of a substrate 6 to transfer the flux 4a, and thereby the flux 4b over the respective lands 7 is applied. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a flux transfer device used for applying a flux to a mounting portion before mounting a solder ball on a substrate.

  Generally, when a solder ball is mounted on a ball grid array or the like on a substrate, a flux is applied in advance to the solder ball mounting portion. By doing so, the oxide film at the solder ball mounting location can be removed and the solder ball can be temporarily fixed at the mounting location, so that highly reliable solder connection can be achieved.

  Conventionally, as a flux transfer device used to apply flux to a solder ball mounting location, a plurality of transfer pins are conventionally held in a predetermined arrangement so as to be movable up and down and attached to the tip of each transfer pin. What is comprised so that a flux can be transcribe | transferred on a board | substrate is widely known.

  FIG. 3 schematically shows such a conventional flux transfer apparatus. The flux transfer device 10 shown in the figure holds a plurality of transfer pins 12 in a predetermined arrangement so as to be movable up and down via an elastic pressing portion 11 including an elastic body such as a spring. It protrudes downward through a guide hole (not shown). The flux transfer method in the flux transfer device 10 will be described. First, the tip 13 (lower end) of each transfer pin 12 is immersed in a flux in a flux tray (not shown), so that the flux 13 is attached to the tip. Let Thereafter, the flux transfer device 10 is brought close to the substrate 14 from above, and the heads of the transfer pins 12 are pushed downward by the elastic pressing portions 11 so that the transfer pins 12 are lowered along the guide holes. Let As a result, the tip of each transfer pin 12 comes into contact with the corresponding land 15 of the substrate 14, and the flux 13 attached to the tip of each transfer pin 12 is transferred onto the corresponding land 15. A flux 13 is applied on top.

  By the way, in this kind of flux transfer apparatus 10, the flux 13 attached to the tip of each transfer pin 12 is wetted to the base side, but as shown in FIG. Therefore, the application amount of the flux 13 transferred onto the substrate 14 tends to vary from one transfer pin 12 to another. Further, when the flux 13 that has been wetted up to the base of the transfer pin 12 is dried and fixed, the transfer pin 12 cannot be smoothly moved up and down within the guide hole, which may cause a malfunction of the flux transfer apparatus 10. there were.

  Therefore, conventionally, a flux having a property of repelling flux (for example, polytetrafluoroethylene) is previously coated on the base side of each transfer pin, and the flux is attached only to the tip side of the coating layer. A transfer device has been proposed (see, for example, Patent Document 1). In this case, the upper end position to which the flux can be attached is defined by the coating layer, and there is no possibility that the flux attached to the tip of each transfer pin will get wet to the coating layer. Flux can be attached, and the amount of flux applied onto the substrate is less likely to vary. Further, since the flux does not wet up to the base of the transfer pin, it is possible to avoid malfunction caused by the flux dried and fixed at the base of the transfer pin being caught in the guide hole.

Japanese Patent Laid-Open No. 2004-47874

  However, in the conventional flux transfer device disclosed in Patent Document 1, after forming the transfer pin, a coating layer must be formed on a predetermined portion except for the tip portion, which increases the cost of the device. was there. In addition, the coating layer formed on the base of the transfer pin that slides against the guide hole may peel off if used for a long period of time. There was also a problem that the performance decreased.

  The present invention has been made in view of the actual situation of the prior art, and the purpose thereof is that the amount of flux applied onto the substrate does not vary from one transfer pin to another, and high reliability over a long period of time. The object is to provide a low-cost flux transfer device that can be maintained.

  In order to achieve the above object, the present invention includes a plurality of transfer pins held in a predetermined arrangement so as to be movable up and down, and a flux capable of transferring onto the substrate the flux adhered to each tip of the transfer pins. In the transfer device, a step portion extending over the entire circumference of the transfer pin is provided at a position a predetermined amount away from the tip end of the transfer pin to the base side, and the flux is attached to the tip side from the step portion. .

  In the flux transfer device configured in this way, it is unlikely that the flux adhered to the tip of each transfer pin will get wet over the stepped portion, so that the same amount of flux may be adhered to each transfer pin. The amount of flux applied onto the substrate is less likely to vary. Further, since there is no possibility that the flux gets wet to the base of the transfer pin, it is possible to avoid a malfunction that is a concern when the flux is dried and fixed at the base of the transfer pin. In addition, since the transfer pin only needs to be formed in a shape having a stepped portion, this flux transfer apparatus can maintain high reliability over a long period of time while avoiding an increase in cost.

  In the above configuration, when the step portion is formed by the groove provided in the transfer pin, the first step portion existing at the boundary between the tip portion and the groove, and the second step existing at the boundary between the root portion and the groove. This is preferable because it can more reliably prevent the flux from getting wet from the tip portion to the root portion. In this case, if the groove depth is about 15% of the diameter of the transfer pin, it is possible to effectively prevent the flux from getting wet while ensuring the required mechanical strength of the transfer pin.

  The flux transfer device of the present invention has a low possibility that the flux attached to the tip portion of each transfer pin will get wet over the stepped portion, so that the same amount of flux can be attached to each transfer pin, There is no risk of the flux getting wet to the base of the transfer pin and drying / adhering. Therefore, variations in the amount of flux applied onto the substrate are less likely to occur, and malfunctions are less likely to occur. In addition, since it is only necessary to form the transfer pin in a shape having a stepped portion, high reliability can be maintained over a long period of time while avoiding an increase in cost.

It is explanatory drawing which shows typically the state which has arrange | positioned the flux transfer apparatus which concerns on the example of embodiment of this invention on the flux tray. It is explanatory drawing which shows typically the state which has arrange | positioned the flux transcription | transfer apparatus on a board | substrate after making flux adhere to each transfer pin of FIG. It is explanatory drawing which shows typically the state which has arrange | positioned the conventional flux transfer apparatus on the board | substrate.

  Hereinafter, a flux transfer apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  The flux transfer apparatus 1 shown in these drawings holds a plurality of transfer pins 3 in a predetermined arrangement so as to be movable up and down via an elastic pressing portion 2 including an elastic body such as a spring. Each protrudes downward through a guide hole (not shown). The transfer pin 3 is provided with a tip portion 3a to which a flux is attached, a root portion 3b inserted through the guide hole, and a groove 3c formed by reducing the diameter between the tip portion 3a and the root portion 3b. The groove 3 c extends over the entire circumference of the transfer pin 3. Thus, since each transfer pin 3 is provided with the groove 3c at a position away from the tip by a predetermined amount from the tip, the boundary between the tip 3a and the groove 3c is the first step 3d. The boundary between the root portion 3b and the groove 3c is a second step portion 3e.

  In this embodiment, the depth of the groove 3c is set to the depth of the transfer pin 3 in order to effectively prevent the flux from getting wet to the root portion 3b while ensuring the required mechanical strength of the transfer pin 3. It is set to about 15 percent of the diameter. Specifically, the diameter of the tip portion 3a and the root portion 3b is about 0.5 millimeters, whereas the diameter of the small diameter portion surrounded by the groove 3c is about 0.35 millimeters.

  When the flux is applied onto the substrate 6 using the flux transfer device 1, first, as shown in FIG. 1, the flux transfer device 1 is brought close to the flux 4 in the flux tray 5 from above. The tip 3 a of each transfer pin 3 is immersed in the flux 4. Since the surface of the flux 4 in the flux tray 5 is leveled by squeezing, it is easy to immerse only the tip 3 a of each transfer pin 3 in the flux 4. In this way, a substantially spherical flux 4a (see FIG. 2) that wraps the tip 3a is attached to each transfer pin 3.

  Note that the flux 4a adhering to the tip 3a of the transfer pin 3 slightly gets wet into the groove 3c, but since the boundary between the tip 3a and the groove 3c is the first stepped portion 3d, the flux 4a enters the groove 3c. The amount of the flux 4a that gets wet is small. In addition, since the boundary between the groove 3c and the root portion 3b is the second stepped portion 3e, there is no possibility that the flux 4a in the groove 3c gets wet into the root portion 3b. Therefore, substantially the same amount of flux 4a that wraps the tip 3a is attached to each transfer pin 3.

  After the flux 4a (4) is attached to each transfer pin 3 in this way, the flux transfer device 1 is brought close to the substrate 6 from above as shown in FIG. Then, each transfer pin 3 is lowered along the guide hole by pushing the head of each transfer pin 3 downward by the elastic pressing portion 2. As a result, the tip of each transfer pin 3 comes into contact with the corresponding land 7 of the substrate 6, and the flux 4 a attached to the tip of each transfer pin 3 is transferred onto the corresponding land 7. A flux 4b (4) is applied on top.

  As described above, the flux transfer device 1 according to this embodiment has no fear that the flux 4a (4) attached to the tip 3a of each transfer pin 3 may get wet to the root 3b. Almost the same amount of flux 4a can be adhered to 3a, and the application amount of the flux 4b (4) transferred onto the substrate 6 is less likely to vary. Further, since there is no possibility that the flux 4a gets wet to the base of the transfer pin 3, it is possible to avoid malfunction caused by the flux dried and fixed at the base of the transfer pin 3 being caught in the guide hole. As described above, in this embodiment, by providing the transfer pin 3 with the groove 3c, the first step portion 3d and the second step portion 3e are interposed between the tip portion 3a and the root portion 3b. Therefore, wetting of the flux 4a toward the root portion 3b is reliably prevented.

  In addition, the flux transfer apparatus 1 according to the present embodiment achieves the above high reliability by forming each transfer pin 3 with a shape with a groove 3c, and the transfer pin 3 is formed with a shape with a groove 3c. Since it is easy to do, this flux transfer apparatus 1 can maintain high reliability over a long period of time without increasing the cost.

  However, even if each transfer pin 3 does not have a shape with a groove 3c, a step similar to the first step 3d or the second step 3e is provided at a position away from the tip of the transfer pin by a predetermined amount. If it is provided and the flux is attached to the tip side of the stepped portion, almost the same amount of flux can be attached to each transfer pin, and malfunction can be avoided, so that reliability can be improved. It is.

DESCRIPTION OF SYMBOLS 1 Flux transfer apparatus 2 Elastic press part 3 Transfer pin 3a Tip part 3b Root part 3c Groove 3d First step part 3e Second step part 4, 4a, 4b Flux 5 Flux tray 6 Substrate 7 Land

Claims (3)

A flux transfer device comprising a plurality of transfer pins held in a predetermined arrangement so as to be movable up and down, and capable of transferring a flux attached to each tip of the transfer pins onto a substrate,
A step portion extending over the entire circumference of the transfer pin is provided at a position away from the tip end of the transfer pin by a predetermined amount, and the flux is attached to the tip side of the step portion. Flux transfer device.   2. The flux transfer device according to claim 1, wherein the step portion is formed by a groove provided in the transfer pin.   3. The flux transfer device according to claim 2, wherein the depth of the groove is about 15 percent of the diameter of the transfer pin.

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