JPS61286060A - Jig member for soldering - Google Patents

Abstract

PURPOSE:To improve the life of a jig member for soldering and to assure stably a joint part having high accuracy by coating a base metal part consisting of a steel in the part to contact with molten solder with a material which is hardly wettable with solder. CONSTITUTION:A film is not particularly limited if the material thereof has the non-wettable property with solder, such as the oxide, nitride, carbide or carbonitride of Ti, Zr, Al, Si, B, among which TiN is more preferable. The steel to be used as the base metal refers to a mild steel, carbon steel, piano wire or structural steel. The surface film is formed to <=10mu onto the above- mentioned base metal and the surface roughness of the part to contact with the solder is adjusted to <=3mum, by which the exfoliation of the coating material is prevented and the local sticking of the solder is prevented. The good coating is obtd. if the film is formed by ion plating, sputtering or vacuum deposition. The life is thus improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a soldering jig member,
For example, the present invention relates to a member such as a support rod for an object to be soldered used in an automatic soldering device, which is required to have the property that solder does not adhere even when it comes into contact with molten solder.

[Conventional technology]

Conventionally, a single piece of tungsten has been used as a support rod that comes into direct contact with molten solder, as disclosed in JP-A-58-81561.

[Problem that the invention seeks to solve]

Conventional support rods for soldering are made of tungsten, which is very expensive and has poor workability, making it difficult to process with high precision. As a result, solder, which should not originally adhere to the tungsten support rod, adheres locally starting from defective parts such as processing scratches, significantly reducing the number of times the support rod can be used repeatedly (life span) and There were problems such as poor quality.

[Means for solving problems]

In the present invention, at least the portion that comes into contact with the melting solder is made of one of Ti, Zr, Al, Si, B oxides, nitrides, carbides, carbonitrides, borides, Mo, W, or alloys thereof. Alternatively, the above-mentioned problem can be solved by coating the soldering jig member with two or more types of solder and a substance that is difficult to wet, and using the base material as a soldering jig member made of steel. Furthermore, the surface roughness of at least the part that comes into contact with the solder is 3μ or less, and the coating is coated with a substance that is difficult to wet with the solder by ion plating, sputtering, or vacuum evaporation, and the thickness of the coating is is desirably 10μ or less.

[Function] Steel, which is the base material, is cheaper than tungsten;
Since it has good workability, soldering jig members can be manufactured at low cost and with high precision.

The parts that come into contact with the melting solder are Tj, Zr, A1
, Si, B oxides, nitrides, carbides, carbonitrides, borides, MOLW, or alloys thereof, which are difficult to wet with solder, so that solder does not adhere to the jig members. The above-mentioned coating also has excellent corrosion resistance against acids, so it is resistant to corrosion by flux, paste, etc., and can be used repeatedly.

The coating in the present invention is TiN, ZrN, or BN.

There are no particular limitations on the material as long as it is a material that does not get wet with solder, such as A1□01.5i02, W, and Mo.

From the viewpoints of adhesion, abrasion resistance, film formability, etc., TiN is desirable as the coating. Moreover, the steel in the present invention is
This refers to mild steel, carbon steel, piano wire, structural steel, carbon tool steel, alloy tool steel, high-speed tool steel, spring steel, and bearing steel. By setting the surface roughness to 3μ or less, local adhesion of solder can be prevented.

When we investigated the cause of local adhesion on conventional tungsten rods, we found that flux residue was trapped in sharp, deep defects such as processing scratches, and this was used as a starting point for solder to adhere to the surface of the tungsten rod, where solder should not get wet. It has been clarified that adhesion occurs.

That is, setting the surface roughness to 3μ or less has the effect of preventing local adhesion of solder. Further, by covering the surface of the deep and sharp defect with the above-mentioned thin film, it is further smoothed and the effect of preventing local adhesion of solder is further improved. Thin film coating is performed by ion plating, sputtering or vacuum deposition.

The surface quality of the film is good, the film thickness is uniform, and it has better solder adhesion resistance. Also, the thickness of the coating is 10μ
If the thickness exceeds 10 μm, the coating becomes easy to peel off, so a thickness of 10 μm or less is desirable.

〔Example〕

Next, the present invention will be explained in detail with reference to Examples.

2 and 5 having the base material, surface coating, and surface roughness shown in Table 1
Five types of test rods of nmφX80 nmQ were prepared, and a solder adhesion test was conducted by sequentially repeating flux application, immersion in a solder bath for 10 seconds, water washing, and drying. Note that the temperature of the solder bath was 250°C.

As can be seen from Table 1, with the conventional commercially available tungsten rod, local adhesion of solder occurred on the surface of the rod after approximately 40 repeated treatments. However, the base material was a round bar of SK5, and the surface was coated with 2 to 3 μm of TiN by sputtering, and the base material was a round bar of 5KD61, and one surface was coated with 3 to 4 μm of TiN by ion plating. The product of the present invention and the product of the present invention whose base material is 5KH51 and whose surface is coated with 3 to 4μ of TiN by ion plating are as follows:
In all cases, no solder adhesion was observed even after repeated processing 300 times. However, a comparative product using 5KH51 as a base material whose surface was not coated with a thin film of a substance that is difficult to wet with solder had solder adhering to the entire surface after one immersion in the solder bath.

Table 1 As a result of using the soldering jig member of the present invention as the lower and upper support rods during IC soldering, no adhesion of solder occurs as described above, and it is possible to use it repeatedly as a support rod. It was confirmed that the quality of the soldered IC was good.

〔Effect of the invention〕

According to the present invention, since steel is used as the base material and the surface is coated with a substance that is difficult to wet with solder, it is possible to provide a soldering jig member that is inexpensive, highly accurate, and can be used repeatedly without adhesion of solder. can.

Claims (1)

[Scope of Claims] 1. A soldering jig member characterized in that the base material is steel, and at least a portion of the base material that comes into contact with melting solder is coated with a substance that is difficult to wet with the solder. 2 Substances that are difficult to wet with solder include Ti, Zr, Al, and Si.
, B oxides, nitrides, carbides, carbonitrides, borides, Mo, W, or alloys thereof. Jig parts. 3. The soldering jig member according to claim 1 or 2, wherein the surface roughness of at least the portion that comes into contact with the melted solder is 3μ or less. 4 Substances that are difficult to wet with solder are ion plating,
A soldering jig member according to any one of claims 1 to 3, which is formed by either sputtering or vacuum deposition. 5. The soldering jig member according to any one of claims 1 to 4, wherein the coating thickness of the substance that is difficult to wet with solder is 10 μm or less.