JP2002086291A - Thread solder, manufacturing device for thread solder and manufacture of joining part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide lead free thread solder which can be inexpensively manufactured with high efficiency, its manufacturing device and a manufacturing method for a joining part, in which the thread solder is used. SOLUTION: By arranging flux 2 along the length direction of a Zn based thread solder base material 1 which does not contain Pb. the thread solder 1 is constituted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thread solder containing no Pb, an apparatus for producing the thread solder, and a method for producing a joint component using the thread solder.

[0002]

2. Description of the Related Art Conventionally, as a solder used for mounting a semiconductor chip or the like on a substrate, Sn-Pb
Solder (melting point 183 ° C.) was used. But P
Since b is harmful to the human body even in a very small amount, lead-free solder that avoids the use of Pb has recently attracted attention. Sn-Ag-Cu based solder, Sn-A
g-Cu-Bi solder, Sn-Zn solder, Sn-Zn
-Bi-based solders and the like are known. Among them, for example, Sn-Ag-Cu-based solder and Sn-Ag-Cu-B
The melting point of the i-based solder is about 210 ° C. to 220 ° C.
It has a melting point difference of as much as 40 ° C. as compared with n-Pb based solder. That is, in the case of an electronic component conventionally soldered with Sn-Pb-based solder, it cannot be soldered unless the temperature is raised to about 40 ° C., and the heat resistance of the electronic component reaches the limit (usually about 240 ° C.). Great care must be taken. For this reason, recently, a Sn—Zn-based solder having a melting point relatively close to that of the Sn—Pb-based solder (melting point 1
(Approximately 99 ° C.) or Sn—Zn—Bi-based solder is in the limelight. For example, Sn-8Zn-3Bi has a solid phase temperature of 187 ° C. and a liquidus temperature of about 197 ° C., which is not substantially different from the melting point of 183 ° C. of the Sb—Pb-based solder.

[0003]

However, these Zn-based solders have a problem that they cannot be soldered under ordinary conditions because oxidation is remarkably generated. For this reason, there has been proposed a method of forming a hardly oxidizable metal phase on the surface of a Zn-based solder by performing plating, vapor deposition, or immersion (Japanese Patent Laid-Open No. 8-164496). According to this method, it is relatively easy to efficiently and efficiently plate a plurality of lumps such as solder balls. That is, a plurality of solder balls are put into the plating solution, and the plating can be easily performed to a uniform thickness while stirring the solder balls in the plating solution. However, in the case of an elongated continuous body such as thread solder, it is desirable to make the plating flow in a relatively short time by flowing the solder into the plating solution, but it is not possible to perform plating with a uniform thickness in the order of several seconds. Impossible. Furthermore, many pre- and post-processing steps are required to perform plating and the like,
The relatively inexpensive Sn—Zn-based solder is expensive.

Accordingly, an object of the present invention is to provide a lead-free thread solder, a device for producing the same, and a method for producing a joint component using the thread solder, which can be produced at a high efficiency and at a low cost.

[0005]

The yarn solder of the present invention has a Z
n and a flux along the length direction (claim 1).

[0006] Since this thread solder contains Zn, it can be soldered at the same heating temperature as in the past without containing lead. However, since Zn is easily oxidized, it is possible to arrange the flux along the length direction, melt the flux, reduce the vicinity of the joint, and solder a clean surface. The above-mentioned flux is a flux having a reducing action, melts at the time of soldering, cleans the surface of the soldered portion by the reducing action, and forms a protective film so that the joint surface and the solder are not oxidized.
At this time, the flux itself forms an oxide or the like, but is formed so as to float on the outer surface of the soldered portion. Further, at the time of soldering, the flux provided on the thread solder is used instead of applying the flux or the like to the soldered joint, so that the number of steps of the flux application can be reduced.

[0007] If the above-mentioned flux is arranged along the length direction, it melts as the soldering is performed and exerts the above-mentioned action, so that it may be arranged in any manner.
For example, in a place where the flux is arranged in the thread solder base material, the thread solder base material may be formed into a tubular shape and housed inside the tubular thread solder base material. Further, a concave portion may be provided along the length direction on the surface of the thread solder base material having a circular cross section, and the flux may be stored in the concave portion. Further, the flux may be applied to only a part of the circular cross section and arranged in a spiral shape in the length direction, or may be arranged linearly. Regardless of the arrangement, as long as they are arranged along the length direction, the soldering temperature is almost the same as in the past, and a Pb-free and highly reliable solder joint can be formed.

[0008] In the thread solder of the present invention, the flux is, for example, a flux film formed on the surface of the thread solder base material.

A flux film can be easily formed on the surface of the thread solder. Therefore, for example, a flux film can be formed on the surface of a commercially available thread solder by using a method such as brushing, spraying, or dipping in a bath. As a result, it is possible to easily manufacture a thread solder with flux, and to form a highly reliable Pb-free solder joint at almost the same soldering temperature as before.

In the above-described thread solder of the present invention, a Sn-Zn based solder or S
Cu, In, Ag in n-Zn-Bi solder, Sn-Zn solder or Sn-Zn-Bi solder
And at least one of Sb can be used (claim 3).

The wire solder having the above composition has a melting point of the conventional Sn
It is almost the same as the -Pb-based solder, and it has been confirmed that the strength of the soldered joint is sufficiently high.

A method for manufacturing a joint component according to the present invention is a method for manufacturing a joint component including a joint portion to be soldered, and includes a step of performing soldering using any of the thread solders of the present invention. Item 4).

By using the above-mentioned thread solder, it is possible to form a highly reliable Pb-free soldered joint at almost the same heating temperature as before without applying flux to the joint. Therefore, it is possible to manufacture a joint component having a solder joint that is gentle to the human body while omitting the steps. In addition, in the above-mentioned joining parts,
All components are included as long as they have a soldered portion, such as a mounted product on which a semiconductor chip or the like is mounted or an electronic circuit.

The yarn solder manufacturing apparatus of the present invention is provided with a supply reel for supplying a yarn solder base material, a winding reel for winding the yarn solder, and a yarn reel base material disposed between the supply reel and the take-up reel. And a flux applying means for applying a flux to the surface (claim 5).

[0015] With the above structure, after the drawing step or the like is completed, the wire is wound around the supply reel, and the surface of the thread solder base material supplied therefrom is coated with a flux having a strong oxidation inhibiting action continuously in a relatively short time. be able to. As a result, the flux-equipped thread solder can be manufactured with high productivity. By applying the flux, it is possible to reduce the portion where the surface of the thread solder base material comes into direct contact with air. When the flux is applied to the entire surface of the thread solder base material, there is no portion directly in contact with air. In addition, during soldering, the flux becomes a liquid having a high reducing property, so that even if there is an oxidized part in a part of the thread solder, the flux is reduced to form a highly reliable solder joint. It becomes possible.

In the yarn solder manufacturing apparatus of the present invention, an oxide film removing means for removing an oxide film of the thread solder base material, which is preferably arranged at a stage subsequent to the supply reel, and an oxide film removing means arranged at a stage before the flux applying means, are provided. Cleaning means for cleaning the thread solder base material from which the oxide film has been removed by the means (claim 6).

According to the above configuration, it is possible to clean the surface of the thread solder base material before the flux is applied, and it is possible to form a more reliable solder joint.

[0018]

Embodiments of the present invention will now be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a sectional view of a thread solder according to Embodiment 1 of the present invention. The thread solder base material 1 is made of Sn-Zn-based solder or Sn-Zn-Bi-based solder, or Sn-Zn-based solder or Sn-Zn-B
The i-based solder contains at least one of Cu, In, Ag, and Sb. The composition of the thread solder base material may be any composition that does not contain Pb, contains Zn, and has a melting temperature substantially different from that of the Sn-Pb-based solder. The flux 2 is arranged along the length direction of the thread solder base material 1, and the thread solder 3 is formed. In the thread solder shown in FIG. 1A, the flux is applied to the entire outer periphery of the thread solder base material 1. In FIG. 1B, a concave portion is provided in a part of the circular cross section, and the flux 2 is stored in the concave portion. In FIG. 1C, the flux is stored in the cylindrical thread solder base material. As long as the flux is arranged along the length direction, the arrangement and shape of the cross section of the wire solder may be any. However, if the period before forming the solder wire after using the solder wire is long,
Since an oxide layer is formed on the exposed base material surface, FIG.
It is desirable that the flux is applied to the entire circumference as shown in FIG.

[0020] The above-mentioned thread solder can be easily manufactured, and at the time of soldering, the flux melts to form a protective film. Can be formed. Conventionally, a flux is separately applied to the solder joint. However, since the flux of the thread solder is supplied to the joint, it is not necessary to apply the flux to the solder joint.

(Embodiment 2) FIG. 2 is a view illustrating a thread solder manufacturing apparatus for manufacturing the thread solder shown in FIG. 1A. In this thread solder manufacturing apparatus, the wire solder base material is immersed in a flux liquid for manufacturing. Referring to FIG. 2, the thread solder base material is unwound from the supply reel 12 around which the thread solder base material after the drawing step has been wound up, and a flux is applied. The whole apparatus shown in FIG. 2 is desirably performed in an oxygen-free atmosphere such as a small chamber purged with nitrogen. The thread solder base material 16 supplied from the supply reel 12 is taken up by a take-up reel 15, and a flux is applied during the winding. In the above process,
It is possible to continuously apply the flux to the thread solder base material. The thread solder base material 16 supplied from the supply reel 12 first reaches the first communication pipe 20. The first communication pipe 20 communicates with the inside of the container 23. Container 23
The inside is filled with dilute sulfuric acid 24 of about 5% to a height level exceeding the height position of the communication pipe. First communication pipe 20
The air side has a hole (not shown) slightly larger in diameter than the thread solder base material, and the container side has a hole (not shown) larger in diameter than the air side.

The first communication pipe 20 is always filled with an inert gas having a pressure higher than the atmospheric pressure, for example, a nitrogen gas so as to prevent liquid leakage. The thread solder base material 16 having passed through the first communication tube passes through the dilute sulfuric acid 24 to remove the oxide film formed on the surface. The thread solder base material 16 from which the oxide film has been removed is connected to the next second communication pipe 2.
One.

The second communication pipe 21 includes a container 23 and a container 18.
Are provided with holes of the same diameter (not shown) on the left and right sides, and connect the container 18 and the container 23. The second communication pipe 21 is filled with an inert gas at a pressure higher than the atmospheric pressure by a predetermined pressure to prevent oxidation, thereby suppressing oxidation. Further, by setting the pressure higher than the atmospheric pressure by a predetermined pressure or more, the dilute sulfuric acid 24 in the container 23 is prevented from being mixed into the cleaning water 17 in the container 18.

The diluted sulfuric acid 24 adhering to the surface of the thread solder base material 16 is washed in a container 18 containing washing water 17.
The thread solder base material 16 that has passed through the inside of the container 18 reaches the next third communication pipe 22. The third communication pipe 22 is provided between the container 11 and the container 18 so as to be filled with an inert gas to suppress oxidation, and holes (not shown) are provided on the left and right sides.
Is provided. The charged inert gas is set to a pressure higher than the atmospheric pressure by a predetermined pressure or more at all times.
9 and the washing water in the container 18 are separated.

The thread solder base material 16 that has passed through the third communication pipe 22 is introduced into the container 11 containing the flux 19, and is passed while passing through the flux 19.
6. A flux 19 is adhered to the surface of the
Up to On the atmosphere side of the fourth communication pipe 14, a hole (not shown) having a slightly larger diameter than the thread solder to which the flux is attached is provided, and on the container 11 side a hole (not shown) larger than the atmosphere side. Is provided. The fourth communication pipe 14 is always filled with an inert gas having a pressure higher than the atmospheric pressure by a predetermined pressure or more, for example, a nitrogen gas so as to prevent liquid leakage.

The thread solder on the surface of which the flux has passed through the fourth communication tube is taken up on a take-up reel 15. Here, hot air may be applied to the flux on the surface of the thread solder 16 that has come out into the atmosphere from the fourth communication pipe 14 to dry the flux quickly.

By using the above apparatus, the flux can be continuously adhered to the surface of the thread solder base material, and the Sn—Zn-based solder that is easily oxidized can be covered with the flux without being oxidized.

In this embodiment, the thread solder base material is passed through the flux container 11. However, instead of the flux container, a brush containing a flux or a flux supply member such as a sponge body may be used.

Although the embodiments of the present invention have been described above, the embodiments of the present invention disclosed above are merely examples, and the scope of the present invention is not limited to these embodiments. Not limited. The scope of the present invention is:
It is indicated by the description of the claims, and further includes all modifications within the meaning and scope equivalent to the description of the claims.

[0030]

By using the thread solder of the present invention,
Since the flux is provided in the Sn-Zn based thread solder base material, the soldering is heated at the same heating temperature as before to form a protective film without applying flux to the joints to achieve reliability. It is possible to form a Pb-free soldered portion having a high Pb-free soldering. In addition, by coating the flux on the entire circumference of the thread solder base material, the Sn—Zn-based thread solder base material that is easily oxidized can be protected from oxidation before use.

Further, by using the yarn solder manufacturing apparatus of the present invention, it is possible to make the surface of the yarn solder base material after the drawing step a highly clean surface and to continuously apply the flux with high efficiency. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a thread solder according to a first embodiment of the present invention. (A) is a one in which a flux is coated on the entire circumference of the thread solder base material, (b) is a one in which a concave portion is provided in a part of a circular cross section, and the flux is stored in the concave portion, and (c) The parentheses indicate that the flux is stored inside the cylindrical thread solder base material.

FIG. 2 is a diagram illustrating a thread solder manufacturing apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

1 Flux solder base material, 2 Flux, 3 Flux solder (with flux attached), 11 Flux container, 12
Supply reel, 14 fourth communication pipe, 15 take-up reel, 16 thread solder base material or thread solder, 17 cleaning water, 18 cleaning water container, 19 molten flux (heated state), 20 first communication pipe, 21 2 communicating pipes, 22
Third communication pipe, 23 diluted sulfuric acid solution, 24 diluted sulfuric acid, 2
5 Gas pressure gauge.

Claims (6)

[Claims] 1. A thread solder comprising Zn and having a flux along its length. 2. The thread solder according to claim 1, wherein the flux is a flux film formed on a surface of the thread solder base material. 3. The method according to claim 1, wherein the wire solder containing Zn is Sn—Zn.
Solder or Sn-Zn-Bi solder or S
3. The thread solder according to claim 1, wherein the n-Zn-based solder or the Sn-Zn-Bi-based solder includes at least one of Cu, In, Ag, and Sb. 4. A method of manufacturing a joint component including a joint portion for soldering, the method including a step of performing soldering using the thread solder according to claim 1. . 5. A supply reel for supplying a thread solder base material, a take-up reel for winding the wire solder, and a flux disposed between the supply reel and the take-up reel for applying a flux to the thread solder base material. A thread solder manufacturing apparatus comprising: an application unit. 6. An oxide film removing means disposed at a stage subsequent to the supply reel and removing an oxide film of the thread solder base material, and an oxide film disposed at a stage preceding the flux applying means, wherein the oxide film is removed by the oxide film removing means. The yarn solder manufacturing apparatus according to claim 5, further comprising: a cleaning unit configured to clean the removed yarn solder base material.