JPH0635053B2 - Soldering jig - Google Patents

Description

Detailed Description of the Invention

 Purpose of the invention

[Industrial applications]

The present invention relates to an improvement of a jig used in a soldering device.

2. Description of the Related Art With the progress of technology using semiconductors, the work of soldering ICs and other electronic components to circuit boards has increased.
The work is mostly automated and consists of holding the circuit board with the parts inserted in it with an appropriate jig, immersing it in a flux bath if necessary, preheating it, then immersing it in a molten solder bath and pulling it up. . Of course, this jig should not be easily wet with molten solder. At present, SUS304 stainless steel coated with Teflon is used as the jig material, but it gradually gets wet with long-term use, so the jig must be replaced after about 6 months of use. I won't. Although Ti is known as a material that is harder to be wetted by solder than stainless steel, it is not suitable for manufacturing a soldering jig because Ti is expensive and has poor workability. It has been found that ceramics are more difficult to get wet and have good resistance to wetting, that is, the property that they are hard to get wet can be sustained, but it is difficult to process them into complicated shapes, so if you dare to use ceramics, , Ti is more expensive.

[Problems to be Solved by the Invention]

An object of the present invention is to solve the above problems and to provide a soldering jig which is hard to get wet with solder and has improved wettability by using a metal material which is inexpensive and has good workability. . Structure of the invention

[Means for solving problems]

The soldering jig of the present invention is basically C: 0.1
0% or less, Si: 5.0% or less, Mn: 2.0% or less and Cr: 5.0 to 30%, and the balance Ni: 40
% Or more and Fe: 55% or less is molded and heated to a temperature of red heat or higher in an oxidizing atmosphere to form a Cr ₂ O ₃ -rich oxide film on the surface. As the material, in addition to the above basic alloy composition, at least one of the following groups (a) Y and lanthanide REM (La, Ce, P
r, Nd, Pm, Sm, Eu, Gd, Tb, Dy, H
o, Er, Tm, Yb, Lu) 1 or more selected from 0.001 to 1.0% (b) 1 or 2 selected from Ca and Mg:
Those containing 0.003 to 0.03% have the advantages that the above-mentioned Cr ₂ O ₃ -rich oxide film is easy to form and that the oxide film is strong and does not easily peel off from the base material. It is the preferred material. When it is desired to increase the mechanical properties of the soldering jig, especially strength, at least one of the following groups is used as a material (C) Mo: 6.0% or less and / or Co: 5.
0% or less (d) One or two selected from Nb, Ta and Zr
It is preferable to use an alloy containing at least seeds: 6.0% or less (e) Al: 7.0% or less. It goes without saying that the above-mentioned optional additional elements may coexist with those belonging to two or more groups. In addition, as the material of the soldering jig of the present invention,
Unless it is against the purpose, it can be used even if it contains alloy components other than the above. Therefore, it is advantageous to select the material from existing commercial standard products in terms of availability and price. For example, Ni 77% or more and Cr 19 to 2
1% as the main component, Ni 57% and Cr 15
-18% as a main component and the balance mainly consisting of Fe, both of which include nickel-chromium alloys and nickel-chromium-iron alloys supplied for heating wires (NCH1 and NCH2 are steel type symbols of Daido special steel). . The formation of the oxide film rich in Cr ₂ O ₃ is 700 to
Temperature of 800 ° C or higher, preferably 1100 to 1200 ° C
The heating may be performed for about 0.5 to 2 hours.

[Action]

When a Ni-based alloy containing Cr: 5.0% or more is heated to a temperature of red heat or higher in an oxidizing atmosphere to form an oxide film, Fe and Ni oxides are of course formed. However, a large amount of Cr ₂ O ₃ oxide is generated in preference to this. This fact was confirmed by the fact that the M ₂ O ₃ type compound was overwhelming when the surface of the material after treatment was examined by X-ray diffraction, and that a large amount of Cr was present when analyzed by EPMA. Was done. Further, the fact that this oxide film had a dense structure and was strongly attached to the matrix was observed by a scanning electron microscope photograph. If the content of Cr is less than 5.0%, this effect becomes weak. On the other hand, the addition of more than 30% only lowers the workability of the material and increases the price, and the effect is saturated, which is not a good idea. C should exist in an amount necessary to secure the strength of the jig. However, if the amount is large, the formation of a dense oxide film is affected, so 1.0% is made the upper limit. Si: 5.0% or less and Mn: 2.0% or less are both added as a deoxidizing agent, but if the respective upper limits are exceeded, Si makes the material mechanically brittle and makes processing difficult. Not only that, there is a risk of penetrating solder due to the generation of fine cracks, and Mn reduces the adhesion of the oxide film to the substrate. Addition of Y and lanthanide-based REM not only produces a dense oxide film as described above, but also enhances the adhesion to the substrate. This effect can be obtained by adding a very small amount of 0.001%. If the amount is large, the hot workability tends to be deteriorated, which is also disadvantageous in terms of cost. Therefore, it is a good idea to limit the addition to within 1.0%. The reason for limiting the addition effect and composition of the Ca and Mg groups is the same as that of the Y- and lanthanide-based REM. Each group of Mo; Nb, Ta, Zr; and Al is
Although this also increases the strength of the material as described above, it also serves to increase the adhesion of the oxide film to the substrate. The effect is obtained by adding 0.002% or more in total. For groups such as Mo and Nb, there is no problem in physical properties even if the upper limit of 6.0% is exceeded, but the price becomes high. If Al is added over 7.0%, the material becomes brittle.

【Example】

Width 14mm x by machining from alloy with composition shown in the table
A plate with a thickness of 2 mm and a length of 200 mm was manufactured. Each sample was subjected to a treatment for forming an oxide film by heating at 1200 ° C. for 2 hours in the atmosphere. The following are typical soldering conditions: Solder used: 63% Sn-Pb (eutectic solder), melting point: 183 ° C Bath temperature: 250 ° C Cycle: (flux dipping + preheating) for about 20 seconds →
Soaking in solder bath Approx. 10 seconds ... Approx. 1000 cycles / 8 hours In order to realize test conditions close to this, a device for grabbing the test piece and immersing the lower half in the solder bath kept at 250 ° C for 10 seconds and pulling it up for 20 seconds Prepared. After 15,000 cycles, the state of solder adhesion was examined.
No solder adhesion was observed in any of the examples. On the other hand, in the comparative example, a large amount of solder adhesion was observed. EFFECTS OF THE INVENTION Since the soldering jig of the present invention is, so to speak, equivalent to a surface of a metal processed product coated with a ceramic containing Cr ₂ O ₃ as a main component, the solder wettability is substantially zero. be able to. This coating is strong and does not come off even after many heat cycles, so it has excellent wetting resistance,
The jig can be used for a long time. Even when a decrease is observed, it can be easily regenerated by cleaning the surface of the jig by means such as pickling and heating. Existing materials that are easily available on the market are sufficient as the materials, and since the workability is generally not bad, the cost of the soldering jig is low, together with the fact that the heat treatment is easy.

Claims (3)

[Claims] 1. C: 0.10% or less, Si: 5.0% or less, Mn: 2.0% or less, and Cr: 5.0 to 30%.
And the balance is Ni: 40% or more and Fe: 55%
A soldering jig formed by molding a material having an alloy composition of the following and heating it in an oxidizing atmosphere to a temperature of red heat or higher to form an oxide film rich in Cr ₂ O ₃ on the surface. 2. As a material, at least one selected from the following groups: (a) One or more selected from Y and lanthanide REM: 0.001 to 1.0% (b) Selected from Ca and Mg. One or two:
The soldering jig according to claim 1, wherein a soldering jig containing 0.003 to 0.03% is used. 3. A material which is at least one of the following groups (c) Mo: 6.0% or less and / or W: 1.5
% Or less (d) One or two selected from Nb, Ta and Zr
The soldering jig according to claim 1 or 2, wherein a solder containing at least one kind: 6.0% or less (e) Al: 7.0% or less is used.