JPH05148692A - Plating jig of electronic parts - Google Patents

Abstract

PURPOSE:To reduce the amt. of a plating soln. to be supplied and to improve the productivity and quality of the product by forming a fluororesin coating layer while leaving a conductive part on a Hastelloy core. CONSTITUTION:The entire part below the upper L-shaped corners b1 and b2 of a Hastelloy core constituting a plating jig is coated with a fluororesin and baked. After cooling, a part of the surface of a current contact 4 is cut by a knife to expose the skin of the Hastelloy core. This plating jig is mounted on a plating device. A part such as a lead frame 5 is placed in the basket of the jig and transported to a plating line. When the jig is used, the soln. is hardly introduced between plating stages, and a uniformly plated product is continuously produced without any defective plating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used to perform functional plating such as solder plating, gold plating and silver plating and / or decorative plating on short or short piece-shaped electronic parts such as short IC lead frames and small contact parts. To a basket-shaped jig for plating.

[0002]

2. Description of the Related Art Conventionally, for plating electronic parts such as short IC lead frames and small contact parts, copper and stainless steel called racks, octopuses, etc., which are well known in general terms, are used as core materials. A part of the part is hooked to a plating jig consisting of a vertically long rod-shaped or flat-plate main body coated with vinyl chloride resin or polyethylene resin, and a small bone with a core exposed for energization. In many cases, another method is to place a metal conductor for electricity on the bottom surface of a mesh basket and bring the part into contact with the conductor by its own weight, and then apply electricity to perform various plating. It has been practiced since ancient times. Also for the latter plating of small contact parts and the like, such a plating method based on its own weight has been actively practiced for a long time.

After such a process, recently, with the progress of automation, the former self-weight plating method for the short IC lead frame has been reconsidered and frequently used due to its advantageous loading and unloading operations. It is like this. For example, regarding plating of short IC lead frames,
By using a self-weight basket-shaped plating jig, loading the lead frame onto the jig requires only throwing the parts into the basket, and unloading is easy by mechanically chucking by position control. Therefore, a very efficient plating facility can be provided. The latter small contact parts are also grouped into a self-weight plating method called barrel plating.

[0004]

As described above, in the plating of electronic parts of short pieces, short pieces, and small articles, necessary electric current is applied to the bottom surface of various basket-shaped containers by the weight of the electronic parts. There are many problems in the structure of the jig, and improvement is desired. In a basket-shaped plating jig, the current-carrying contacts by its own weight are usually placed on the bottom of the jig.
Other parts are made of coarse mesh, grid, comb-like electrical insulator to hold the parts, and the energizing contacts are made of copper or stainless steel, and the electrical insulator of the holding part is glass. It is formed of fiber reinforced PPS (polyphenylene sulfide), or is formed by coating a conducting metal such as copper or stainless steel as a core material with vinyl chloride resin, polyethylene resin or the like. Therefore, both of them have the following problems. i) Within a short time after the start of use, the copper and stainless conductive contacts arranged on the bottom of the basket are eroded by various chemical solutions in the plating process, resulting in poor plating and severe damage to the jig. ii) The corroded contact metal is mixed in each liquid in the plating process, which deteriorates the liquid quality and shortens the liquid life, resulting in frequent plating defects. iii) The temporary adhesion state between the metal surface of the current-carrying contact and the plating film attached to it is unstable, and the film is dropped during the plating process, and it re-adheres to the plating surface of the component and causes plating failure. Break the plating solution. iv) When the basket body is made of glass fiber reinforced PPS, there is no major problem with chemical resistance, but there is no water repellency, rather hydrophilicity, and as a result,
A large amount of process liquid attached in the previous process is brought to the next process,
The liquid in each plating process is destroyed and defective plating frequently occurs. In particular, the pure water used for cleaning in the final step may be destroyed and may remain in the product, often significantly reducing the reliability as an electronic component. v) A basket in which a core material such as stainless steel or copper is coated with vinyl chloride resin, polyethylene resin, or the like is corroded by the plating process liquid in a short time and is unsuitable as a jig for plating electronic components.

Therefore, there is a particular demand for improvement and research on conventional plating jigs used for plating electronic components.
When the above problems are sorted out, the basket-shaped plating jig is a rational and preferable one as a plating means for electronic parts in terms of loading and unloading of parts to be plated. Yes, corrosion resistance against chemicals used in the plating process of the conductor metal of the energizing contact located on the bottom of the basket and stability of temporary adhesion of the plated metal adhering to the energizing contact are required.
Corrosion resistance to chemicals used in the plating process of the so-called electrically insulative basket body to hold the electronic parts so that they do not fall off during the plating process, and carry-in of the chemical liquid of the previous process to the next process are required. , The emergence of a jig for basket-like plating of electronic parts that solves these problems is awaited.

In view of the above situation, an object of the present invention is to provide a basket-like plating jig for electronic parts, which can solve the above-mentioned conventional problems.

[0007]

In order to solve the above problems, the inventor of the present invention examined the material of the basket. In the process, glass fiber reinforced P
A basket was made of PS, and a copper strip pre-plated with nickel was placed on the bottom surface of the basket as the electrical contact for the cathode current. Also, using a stainless steel wire as the core material and thickly coating vinyl chloride resin on this, a basket is made, and the electrical contacts for the cathode current are made by scraping off part of the vinyl chloride resin on the bottom surface of the basket to make a stainless steel wire. The structure is such that the surface is exposed.

However, of the conventional type of basket-shaped plating jigs thus formed, the jigs using PPS are used for about one month, and the cathode current contacts made of nickel-plated copper strips are used for the plating process. In addition to being eroded by the chemical solution of 1 and becoming unusable, a large number of plating defects caused by the dissolved copper ions occurred. The thickness of PPS is 8 mm in diameter.
I used the one of the above, but the lack of strength is conspicuous overall, and P
Since a lot of liquid was brought out and brought in during the plating process due to the hydrophilicity of PS, the plating liquid was destroyed, and the final pure water for cleaning was contaminated, resulting in a markedly poor product quality.

In the basket made of a stainless steel wire coated with vinyl chloride resin, the exposed stainless steel portion for electrical contact was completely eroded by the chemical liquid in the plating process about one month after use. Also,
It is unavoidable that a gap is created between the vinyl chloride resin coating layer and stainless steel, and each liquid in the plating process accumulates in this gap, which greatly affects all of the plating process liquid, causing a pile of plating defects. Oops.

Therefore, the present inventor separately conducted basic tests on corrosion resistance and behavior of the metal of the core material and the resin for electrical insulation with respect to the plating process liquid. As a result, platinum, titanium, and three types of Hastelloy remained as corrosion-resistant metals in the plating process liquid of the electronic component, but further examination of this revealed that platinum was not thick enough to obtain sufficient strength, and, Above all, it is an expensive material and is not suitable for practical use. It has been found that titanium cannot be used when it is used as a cathode, because hydrogen absorption becomes brittle and the current stops flowing. Also, there is a titanium with a thin coating of platinum, but in any case it was concluded that it is not suitable because it is expensive and difficult to process. Compared to these, Hastelloy containing nickel and molybdenum as the main components of the alloy is relatively inexpensive, has high strength, good heat and oxidation resistance, and above all, has sufficiently good corrosion resistance to plating process liquids and is completely unexpected. As a result, it was found that the temporary adhesion of the plating was good. Needless to say, it is important in the industry to recognize that the temporary adhesion of the plating is important in order to prevent the plating layer adhering to the cathode current contact from falling off during the plating process and adversely affecting it. Is.

Next, as a result of conducting a test of the electrically insulating resin, there are many resins having good corrosion resistance in the plating chemical liquid, and a description thereof will be omitted. However, examples of those exhibiting almost complete corrosion resistance by themselves are polyethylene and polypropylene. , PPS, ethylene difluoride resin, ethylene trifluoride resin, ethylene tetrafluoride resin, vinyl chloride resin and the like. However, although each of these resins has corrosion resistance but has a drawback in strength when used alone, it is suitable to coat the core material for use. However, when metal is used as the core material and coated on it, it must be further selected.

That is, although the above-mentioned resins such as polypropylene resin and resins other than PPS are suitable for coating on the metal core material, vinyl chloride resin is further excluded in consideration of the adhesiveness with the metal core material. Furthermore, polyethylene resin is excluded from the viewpoint of water resistance and prevention of adhesion of plating process liquid. Thus, it was found that a fluororesin formed by polymerizing a monomer in which hydrogen atoms in 2, 3, or 4 ethylene atoms are replaced by fluorine atoms is suitable as an insulating resin for a jig for electronic component plating. ..

It was also found that this fluorine resin can be coated on a Hastelloy core material, and the coating layer can adhere to the Hastelloy core material. In conclusion, the present invention has been completed. That is, the present invention provides a basket-shaped plating jig for electronic components, in which a core material forming the jig is made of Hastelloy, and a portion for energizing the electronic component to be plated is provided on the surface of the core material. Remaining is to provide a jig for plating electronic parts, which is coated with a fluororesin.

The fluororesin coating layer can be formed of various fluorine resins such as difluoride, trifluoride, and tetrafluoride, but among them, it is formed of tetrafluoroethylene resin that has a water-repellent property and is not liquid compatible. Preferably. Further, in order to improve the strength of the fluororesin coating layer, the fluororesin coating layer is formed by an intermediate layer made of a fluororesin containing a hardening composite material and an outermost surface layer made of a fluororesin simple substance formed on the intermediate layer. You may comprise.

Also in this case, a tetrafluoroethylene resin can be adopted as the fluorine resin. Examples of the hardening composite material include graphite, carbon, and ceramic powder. In any case, in terms of its structure, the jig according to the present invention is preferably one that does not bring in or bring in the plating solution, and it is desirable that the component to be plated is easy to plate.

With respect to this point, the present inventor also examined what kind of basket shape is preferable. As a result, they have found that it is more effective to construct the skeleton of the basket with the simplest possible shape and using the thinnest possible wire. Therefore, in the jig of the present invention, it is conceivable that the core material is mainly made of Hastelloy wire.

If such a wire is too thick, proper plating cannot be obtained because it shields the necessary plating surface of the electronic component to be plated, and it is easy to carry out and carry in each chemical solution in the plating process. The quality of the electronic parts of the above will be deteriorated and the plating solution will be destroyed. Therefore, the thickness of the wire rod that makes up the basket body is 5 mm for a square rod.
The angle is preferably less than or equal to the corner, and the diameter is preferably 5 mm or less in the round bar shape.

The structure of the basket does not necessarily have to be a net-like basket, and may be any space that does not block the current unless the electronic parts fall off.

[0019]

The plating jig of the present invention is attached to a carrier of a plating line for electronic parts in consideration of ensuring energization, and the plating process is moved according to a predetermined sequence and program so that the plating jig can be used. It is possible to apply the necessary plating to the electronic components placed in the jig.

Since the plating jig of the present invention has a basket shape, loading and unloading of electronic parts by loading and unloading of electronic parts can be automatically performed by a general chucking machine. Since the jig for plating of the present invention is formed by forming the fluorine resin coating layer on the Hastelloy core material, there is no familiarity with the plating process liquid due to the action of the coating layer, and the plating process liquid is taken out and carried in as much. Further, since the electric contact portion is a part of the exposed Hastelloy core material, it is less corroded and has good temporary adhesiveness for plating. Furthermore, as a combination characteristic of the fluororesin layer and Hastelloy, there is no gap between the two, and the pumping liquid for the plating process is less.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of an example plating jig. This jig is for plating the short lead frame 6 on which the integrated circuit chip 51 is formed.
Part 1 having a predetermined length L longer than the lead frame 5
Locations b1 and b2 where both ends a1 and a2 of A are bent at right angles in the same direction and are raised, and the same length is raised from the portion 1A.
The bottom end of the V-shaped wire 2 having a height H is bent in parallel with the portion 1A so as to extend in directions opposite to each other, and is equidistantly arranged on both ends a1 and a2 of the bottom 1A and an intermediate portion thereof. To fix the wire rods 2 in a comb shape, and fix the wire rod 4 for the cathode current contact, which is short on the bottom portion 1A, at the intermediate portion between the adjacent wire rods 2 and 2 in the right angle direction. The short wire 3 is provided to the V-shaped wire 2 at a position slightly raised from both ends a1 and a2 of the bottom portion.
It is formed in a basket shape having a simple structure as a whole. The cathode current is used so as to flow from the end portion of the wire rod 1 or the like.

Short lead frame 5 to be plated
Is fitted into the V-shaped wire rod 2 in a horizontally long posture, is supported by contacting the bottom wire rod 4 (cathode current contact), and leans against these wire rods 2. The wire rod 3 should be removed in the longitudinal direction of the lead frame.
Is prevented by. Increasing the voids with a simple structure mainly composed of wire like this jig structure reduces the surface area occupied by the jig constituent material, and the plating chemical liquid is not taken out and carried into the next process liquid. Therefore, it is advantageous.

In the first example, each of the wire rods 1 to 3 constituting this jig has a wire rod cross section as shown in FIG.
Fluororesin (difluoride, trifluoride,
It may be either tetrafluoride, but tetrafluoride is particularly preferable). The wire 4 is also formed from the Hastelloy core material 6.
Since this is used as a cathode current contact, no coating layer is provided. At the portions where the wires 1 to 4 are connected to each other, first, the Hastelloy cores are fixed to each other by welding, and then the coating layer 7 is formed thereon except the cathode current contact 4. Therefore, the structure is such that if electricity is applied from the upper part of the wire rod 1 in the figure, the entire power can be distributed without any trouble.

In the second example, each of the wire rods 1 to 3 is provided with a fluororesin primer layer 9 on the core material Hastelloy 6 as shown in the wire rod cross section in FIG. A hard fluororesin intermediate layer 8 containing a composite material such as powder is provided, and a tetrafluoroethylene resin layer 7 is further formed as an outermost surface on the hard fluororesin intermediate layer 8. In this example, since the hard intermediate layer 8 is provided, it is possible to use Provided is a scratch-resistant and better plating jig for electronic components.
The other points of the second example are similar to those of the first example.

The overall shape of the jig is not limited to the above example, and various structures and shapes can be adopted as long as they are devised so as to reduce the carry-out and carry-in of the plating process liquid. In any of the above examples, the thickness of the fluororesin coating is not particularly limited, but about 0.03 mm to 2 mm is suitable as a whole. Further, specific examples of commercial products of the fluororesin to be used include those commercially available as normal Teflon coating materials such as "Blue Arma" manufactured by DuPont and "Aflon" manufactured by Asahi Glass Co., Ltd.

As for the Hastelloy core material 6, a round bar is generally easily available as a Hastelloy wire, and it is advantageous to use the rod as it is. Regarding the thickness of this Hastelloy wire, it is generally easy to obtain 2-9 mm, but 2-5
A wire having a diameter of mm is suitable for carrying out the present invention. Note that Hastelloy is an alloy containing nickel and molybdenum as main components, and depending on the grade of this alloy, there are those containing iron, chromium, tungsten, etc., but they are all used without any problems in the present invention.

As the liquid for the electronic component plating process used in the plating process using the jig of the present invention, various chemicals such as nitric acid, hydrogen peroxide solution, and halogen compounds can be used in addition to various plating liquids. For this reason, the specifications of the plating jig of the present invention are important. Next, more specific Examples 1 and 2 will be described. The overall structure of these examples is as shown in FIG. (Example 1) With a diameter of 3 mm, alloy components (Ni 55.5-
59.5%, Mo18-22%, C0.04-0.1
5%, Fe 18-22%) using a so-called grade 42 Hastelloy core material 6, as shown in Fig. 1, width W30mm x length L200mm x height H50mm.
Of the above structure, and then a tetrafluoroethylene resin (Teflon manufactured by DuPont) is applied to the entire lower part of the upper L-shaped corners b1 and b2 of the structure at a high temperature of 420 to 530 ° C. to a thickness of 0.5 mm. It was baked and coated.

Next, after cooling, a part of the surface of the current contact 4 was cut with a knife to expose the surface of the Hastelloy core material 6. The lead frame 5 was attached to the automatic transfer type solder plating device (not shown) through the uncoated L-shaped corner of the plating jig formed as described above, and then to the lead frame 5 by an automatic chucking device (not shown). Then, it was placed in the basket portion of the plating jig and conveyed to the plating line.

Nitric acid treatment as pre-treatment and post-treatment for plating,
Halide treatment, alkali treatment, etc. were performed. As the solder plating liquid, a commercially available organic acid type liquid was used. Plating is 2
Performed for 10 min at A / dm ² , resulting in an average thickness of 8
Very uniform plating of ~ 10μm and no stain, and
Products without defective plating could be continuously produced, and the yield was almost 100%.

Further, when this plating jig is used, liquid is hardly mixed during the plating process, good plating can be obtained, and as a result, the running cost is remarkably reduced. In addition, the jigs have a long lifespan and almost no replacement is required throughout the year. (Example 2) Diameter 4 mm, alloy component Ni53%, Mo2
A structural substrate similar to that of Example 1 was made from the Hastelloy core material 6 containing 4% Cr, 3% Cr and the balance being Fe, and as shown in FIG. 3, the tetrafluoroethylene resin was first subjected to a temperature condition of 505 ° C. Fluorine resin 9 consisting of 0.15m
m baking coating, and then at a temperature of 490 ° C., a hard fluororesin 8 consisting of 35% graphite powder having an average particle diameter of 25 microns and 65% tetrafluoroethylene resin was used.
It was baked and coated so as to be laminated by 7 mm.

Finally, on this surface, a fluorine resin 7 made of tetrafluoroethylene resin having a thickness of 0.2 mm is formed.
Baking coating was performed under a temperature condition of 0 ° C., and as a final treatment, heat treatment was performed at 400 ° C. for 30 minutes. Next, a part of the coating layer of the current contact 4 was scraped off with a sander to expose the surface of Hastelloy 6.

The jig thus obtained is attached to an automatic transfer lead frame solder plating device,
A short lead frame was placed in the jig and passed through each tank in which a commercially available pretreatment liquid, plating liquid, and posttreatment liquid were placed. 1
It was possible to perform extremely high-accuracy solder plating of 8 μ ± 1 μ by performing plating treatment at 5 A / dm ² for 3 minutes. This plating jig has good wear resistance, corrosion resistance, etc., has a long life, and can be continuously used without any defect even in a one-year durability test.

[0033]

According to the present invention, it is possible to provide a plating jig for electronic parts having the following advantages. Since the Hastelloy core material is provided with a fluorine resin coating layer, the coating layer does not familiarize with the plating process liquid, and the plating process liquid is not brought out or carried in as much as that. Therefore, the plating process liquid should be destroyed. Less, which in turn lowers running costs, improves productivity, and improves product quality. Furthermore, as a combination characteristic of the fluororesin layer and Hastelloy, there is no gap between the two, so there is less pumping out of the plating process liquid, and in this respect too, there is less destruction of the plating process liquid, which in turn results in lower running costs and productivity Also improves and product quality improves. Since the electrical contact part is a part of the exposed Hastelloy core material, there is less erosion, the jig life is extended accordingly, productivity is increased, plating cost is reduced, and erosion is less, so the plating process liquid deteriorates. It will be reduced by that much and the product quality will be improved. Since the electrical contact portion is a part of the exposed Hastelloy core material, the temporary adhesiveness of the plating is good, and thus the contamination of the plating process liquid is prevented and the product quality is improved. When the fluororesin coating layer is composed of an intermediate layer made of a fluororesin containing a hardening composite material and an outermost surface layer made of a single fluororesin formed on the intermediate layer, abrasion resistance is caused by the presence of the intermediate layer. Durability and corrosion resistance are improved, and the service life is extended accordingly. When the entire jig is formed by using the core material mainly of Hastelloy wire, the overall structure and shape can be simplified to reduce the carry-out and carry-in of the plating process liquid.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an example of a wire rod that constitutes the jig shown in FIG.

FIG. 3 is a cross-sectional view of another example of the wire rod that constitutes the jig of FIG.

[Explanation of symbols]

 1, 2 and 3 Wire material 4 Wire material (for current contact) 5 Short lead frame 6 Hastelloy core material 7 Fluororesin layer 8 Hard fluororesin layer 9 Primer fluororesin layer

Claims (5)

[Claims] 1. A basket-like plating jig for electronic parts, wherein a core material forming the jig is made of Hastelloy, and a portion for energizing the electronic parts to be plated is left on the surface of the core material. And a jig for plating electronic parts, characterized by being coated with a fluororesin. 2. The jig for plating electronic parts according to claim 1, wherein the fluororesin coating layer is made of tetrafluoroethylene resin. 3. The fluororesin coating layer comprises an intermediate layer made of a fluororesin containing a hardening composite material, and an outermost surface layer made of a fluororesin formed on the intermediate layer. Jig for plating electronic parts. 4. The jig for plating an electronic component according to claim 3, wherein each of the fluorine resin in the intermediate layer and the outermost surface layer is a tetrafluoroethylene resin. 5. The jig for plating an electronic component according to claim 1, wherein the core material is mainly a Hastelloy wire rod.