JPS6037605A - Ag-coated cu electronic component material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Mizumoto 1111 has Ao
Or A(I) relates to an electronic component material coated with an alloy, and in particular provides an economical material that satisfies various properties required for component materials.

Generally A(+ or AQ alloys, e.g. Ag-In, Ao
Alloys such as -Pd and Ag-Au are corrosion-resistant conductors and have excellent solderability and electrical connection.
A substrate made of an alloy such as -Be, Cu-Ti, Cu-Fe, etc., whose surface is partially or completely coated, is used as an electronic component material.

Electronic components such as contacts such as switches and connectors, substrates such as semiconductors and integrated circuits, and lead materials are assembled by soldering or brazing, and they themselves are soldered (=l) to circuits, etc. Solderability has become an essential condition for electronic component materials.

Cu and Cu alloys form a strong oxide film even when stored at room temperature, making them ideal for resin molds used in the assembly process of electronic components.
Activated flux is used to solder Cl and Cu alloys in high-temperature environments such as Gicor, soldering (pump, performance adjustment 1-zinc), etc., which generate thick oxide scales that seriously impede solderability. However, since residual flux causes fatal corrosion damage, careful cleaning is required and it cannot be applied to electronic parts.Also, do not expose parts to the atmosphere in a reducing atmosphere. Although it is possible to assemble the parts, this method is not practical in terms of equipment or economy.

Reasons for using AU-coated Cu-based materials in electronic component materials)
E
Another reason is that it is difficult to form an oxide film on the surface (and good electrical connectivity is required for contacts, etc.).The effect of A(l) can also be obtained with noble metals such as △u and Pt. However, they are industrially uneconomical because they are 10 to 100 times more expensive than A (I), and Tsuki is using Ag or Δg alloy to a thickness of 2 to 3μ or more. Covered.

Recently, with the dramatic development of electronic equipment, it has become desirable to save Ag not only from the viewpoint of flow efficiency but also from the standpoint of resource conservation. But A! If the + coating thickness is made thinner, the following defects will occur.

(1) Although the method and conditions for v-setting are also J, the Ag diagram becomes porous and the base material Cu or Cu alloy is exposed through a so-called pinhole.

(2) Due to the in-phase reaction, the base metal components of the base material reach the surface and deteriorate, degrading the above-mentioned properties of Ag.

In particular, the progress of this reaction is related to an exponential function of temperature and becomes more pronounced under high temperature conditions.

The same problem occurs even with expensive Al coatings, and to prevent this, a Ni intermediate layer between the substrate and the AU layer has been put into practical use, and the above defects can be substantially reduced. , an intermediate layer is usually provided with a thickness of 1 to 2 μm or more, and an A layer with a thickness of 0.2 to several μm is provided on top of the intermediate layer, depending on the application.
U coated with plating or the like is used for contacts, etc.

Even with Ag-coated products, there is I in Ni between the substrate and Ag6? 8
One layer has been put into practical use for semiconductor lead frames, various contacts, terminals, etc., and is usually 0.5 to 3μ thick.
An intermediate layer is provided to prevent pinhole corrosion and keep the surface of the Aa coating clean, as well as to prevent high temperature diffusion of base metals from the base. However, it has been reported that when exposed to high temperature environments, the solderability deteriorates, and sometimes the layer peels off.

In view of this, the present inventors conducted various studies and found that this phenomenon is unique to Ail coating, and does not occur at all with AII coating. That is, from a humidity of around 180°C, atmospheric oxygen easily permeates through the A (1 layer), and perhaps because the permeating oxygen is atomic, it is particularly active and oxidizes the N1 surface under the Ag layer, causing the Ag layer and N1 layer to oxidize. It breaks the metal bond at the interface and drastically reduces the adhesion.

A again! The I layer dissolves rapidly in the solder bath, with a thickness of 2 to 3 microns dissolving in one second under practical conditions. Therefore, during the soldering process, the thin Au layer dissolves and a hard Ni oxide surface that does not wet with solder is exposed, significantly inhibiting solderability. (In the case of CU, during mechanical deformation, external force concentrates on the N1 layer, which is harder than that of CU, and micro cracks that start from the N1 layer and reach the surface of the eight layers are likely to occur.) .

Since the electronic device component C is subjected to jΔ due to precision machining, minute cracks occur during bending and drawing, which not only expose the base and cause corrosion, but also cause corrosion due to the physical condition of the corrosive material P#. The crack expands and becomes a serious defect.

Business details 11 [I L-t 7 /7'l J-ro h sum
Eyes L-That's it 7 η Huh? ? As a result of various studies to achieve R3, we found that an economical A (l-coated Ckl-based electronic component material with flt
In materials where at least part of the surface of a Cu-based substrate is coated with 80 or A9 alloy, an intermediate layer made of Pd or Ru with a thickness of 0.01 to 0.25μ is formed between the substrate and the Ag or Ag alloy layer. It is characterized by having a layer.

That is, the present invention uses wires, rods, strips, plates, etc. made of Cu or Cu alloy as a base, or processes a part or all of them into a part shape to make a base, and a part or all of the surface thereof is made of a wire, rod, strip, plate, etc. 0.
An intermediate layer (hereinafter referred to as PD, RLI intermediate layer) consisting of PD or Ru with a thickness of 0.01 to 0.25μ is formed, and 80 or A! It is coated with a + alloy layer (hereinafter abbreviated as Ag diagram).

Diffusion reaction with Cu-based substrate such as pd or 1luL,
It also has excellent oxidation resistance and effectively prevents the defects described in (1) and (2) above in coatings of 80 or A (1 alloy). 80, which is also a noble metal, reacts with the substrate and Ag IIJ cannot maintain the above-mentioned diffusion prevention effect because it is easy to
Like Pd and Ru, r has oxidation resistance and is effective in preventing diffusion, but it is 10 to 100 times more expensive than Pd and Ru, and it is difficult to practically form a thin intermediate layer by electroplating. Since it is S, it is impractical. Compared to this, Pd or R
U is about 5 to 10 times as expensive as AQ, and is the cheapest negative metal after Ag. Moreover, as an intermediate layer with a thickness of 0.1μ, A (the thickness of one layer can be reduced by 1μ or more) It is also practical.

Although it is desirable for the thickness of the Ru intermediate layer to be as thin as possible for the above-mentioned economic reasons, it is practically set to 0.01 to 0.25 .mu.m. Such a thin intermediate layer allows Cu-based base components such as CLI, Zll, Sn, etc. to pass through and diffuse into the Afl, improving sulfidation resistance and wear resistance without impairing soldering TJ properties. Furthermore, with the increasing density of electronic devices, we have developed a technique for electrolytically transferring fJ from the + side of Ag to the other side, which occurs when used in DC circuits, which is becoming more important as the density of electronic devices becomes higher. Fatal defects can be suppressed. However, P(1 and Ru are Qu and A!+,
J: Hard metal, especially electroplated P(I
When plating, 1-1z tends to be occluded and there is a strong tendency for hard embrittlement. Exposure causes oxidation.

If the thickness is less than 0.01 μm, the diffusion of the Cu-based base component in the A(] layer becomes excessive, and it accumulates on the surface of the A(1 layer), deteriorating the scratch resistance.

The electronic component material of the present invention has the above-mentioned structure, and is manufactured by electroplating, ion blating, sputtering, vacuum a-deposition, mechanical cladding, or a combination of these methods. In particular, the electroplating method uses simple equipment and can quickly plate a coating of an accurate thickness on any desired area. That is, after cleaning a C1-based substrate by a density method, it is electroplated in a Pd or Ru plating bath, and then electroplated in an 80 or Ag alloy plating bath.

1) In the d plating bath, Pd (N+-13)2 (
NO7)2 or Pd (NHg)4 Cj! , 7 as the main ingredients, or a strong sulfuric acid bath containing a sulfite complex, and commercially available baths containing various additives are also available. Ru plating baths include nitrosylsulfamic acid baths and nitrone chloride baths. Examples of the A(+ plating bath) include a cyanide bath, a diosyanide bath, a pyrophosphoric acid bath, and an iodide bath.

The present invention will be described in detail below with reference to examples.

Example (1) A brass plate (35% Zn) with a thickness of 0.42 mrn was degreased and pickled using a conventional method, and then the following plating bath was used to produce the Ag-plated lead frame material for the die λ-de shown in Table 1. was manufactured.

Pd plating bath (III Chuman Metal Balladic MS) P
d i09/J PI-18,5 Bath temperature 55°C Current density 3. OA /dm2 Ru plating bath (Run 7 Nex made by Tanaka Kinzoku) Ru iJ
//Bath P 1 1.5 Bath temperature 60℃ Current density 3. OA/dm2 p Ni plating bath Ni (SO3NH2)2 500g/(NiCJ2
30q/1 H3BO330shi/(PH2,!1 Bath temperature 50℃ Current density 2.5A/dm2 Ag strike plating bath AQ CN 3 g/f! KCN 30J/E bath Humidity 20℃ Current density 3A/dm2 Ag plating bath A (ICN 3047/Jl! KCN 40g/β Kz COs 20y/J! Bath temperature 20°C Current density 1.5Δ/dm2 Ag plating lead frame material for die A-de is in notice book form (+1J5.Om, 81 chips were soldered to -QW (95% Pb-5% Sn, temperature 320℃,
After that, seal the key L with 4Ii1 fat (temperature 18 minutes).
0°C, 5n yen, popular), and then half-[fl 1"J is cut into the printed circuit board. This half-111
3, the wetted area is required to be 90% or more when the crystal is dipped for 5 seconds in a bath at a temperature of 235°C. 1. After removing the lead frame, heat it at a temperature of 100°C for 24 hours to prevent deterioration due to storage and bending.
The wetted area was measured by dipping one end for 5] seconds at a temperature of 320°C (S11, temperature 320°C), and then heating it for 5-1 minutes at a temperature of 180°C, then dipping the other end at a temperature of 235°C. C
Dip in the eutectic half + 1] bath for 5 seconds and
The surface area was measured. Also, 1) Rule 11 is bent and added to the shrine.
After sealing, seal the end surface with lacquer and
, -2371, a 5% salt water spray test was conducted for 24 hours to examine the occurrence of blue copper corrosion at the bent portion. Furthermore, two pieces of this were placed opposite each other at a spacing of 4.0 M on a qualitative filter paper, and the temperature was set at 60°C.
℃, 95% humidity, IW R, J3, 100V electric power was applied, and the insulation resistance was determined after 48 hours. These results are shown in Table 1.

Record.

1@translation glass # 1 p8 feather θ ma 8 vassal Tomobe Shitomi 8 r - Tsuchi 1 next story Miyako 1111cLE = = l:fCLQ:'Zl 12
2 "Dimension Ll")■■■♀=♀ As is clear from Table 1, the wood invention month No. , 3~N
It can be seen that O36 has excellent soldering properties on both sides, no blue copper corrosion occurs (and insulation resistance is also good).

On the other hand, comparative material No, 1, N which does not form an intermediate layer
Comparative material No. 0.2, in which the thickness of the Pd intermediate layer is 0.005 μm, has significantly lower eutectic soldering properties after heating in the air, and the I!!1 layer in PD or Ru Comparison material No. 9, 7 to 8 and N1 intermediate layer were set up. In order to obtain the same performance as the material of the present invention, blue #1rf4 food is generated, and in particular, in order to obtain the same performance as the material of the present invention, the N1 intermediate layer should be set (without adding 80 to 4 μm or more thick).
It turns out that I need to nozuru. Further, comparative materials No. 7-, 'fj3, N, in which Pd or Ru intermediate cancer was made thicker by 0.5u
i middle 1f! Comparative material No. 10.12 with one layer, and comparative material No. 12 with Ao thicker than 4μ without installing an intermediate layer, both have lower insulation resistance and a higher risk of short circuit. I'm in b.

In this way, the material of the present invention highly satisfies properties such as solderability, corrosion resistance, workability, and migration, and
By forming an inexpensive intermediate layer of d or RU with a thickness of 0.01 to 0.25μ, it is possible to save Ag with a thickness of 3μ or more, which is economically advantageous.

Example (2) Using a phosphor bronze strip with a thickness of 0.25M, Dli
After washing with oil and acid, Lad or Ru plating was performed in the same manner as in Example (1), and then Ag plating with a thickness of 17 and 1.5μ was applied to form the connector A! shown in Table i2. + Manufactured plated contacts.

This contact material is usually press-molded and then connected to the electric wire by soldering (Ji) at the 91" part, and the contact part is connected to the circuit bin on the printed circuit board with a cart of about 1007 r, and is suitable for long-term use. The condition is that the contact resistance does not exceed 107 + 1Ω.The contact part (similar to normal contacts, has a convex overhang to stabilize contact with the other party).

In order to prevent deterioration of this contact material during storage and molding processing, the temperature is 60℃ and the humidity is 95%.
After holding the sample for a certain period of time, it was soaked in a eutectic solder bath at 235° C. for 5 seconds to examine solder wettability. After being kept under the humidified conditions described in J and L for 1000 hours, it was heated to a temperature of 250°C for 10 hours.
Heat for 20 minutes, then hold at a temperature of 120℃ for 200 minutes, and then apply a cliff with a diameter of 4. Move the hemisphere of Omm to the right A (
Press the + rod with a load of 1009, and the current is 100 mA.
The contact resistance was measured. Furthermore, a connector was molded and subjected to the same treatment, and a bent pin (0,62
A similar contact resistance was determined by inserting a (mm square). These results are also listed in Table 2. .

Table 2/J 18 Ru O,8n 7,5 >50n+9-
3.0 90 16,9 15. On 20- -
4.5 95 5.8 7.7 As is clear from Table 2, the materials of the present invention Nos. 0115 to 16 exhibit good properties in terms of both solderability and contact resistance. On the other hand, with comparative materials No. 17 to 18 in which an excessively thick Pd or Ru intermediate layer was formed, no deterioration in soldering properties was observed, but the connector contact resistance increased significantly, and comparative materials without an intermediate layer NO
, 13, 19, and 20, it is clear that the thickness of the Aa layer needs to be 4.5 μm or more.

As described above, according to the present invention, the Pd or Ru intermediate layer is formed in an acidic manner contrary to conventional wisdom.
In A5, it exhibited a unique and useful action, and its properties were significantly improved. In particular, it can withstand high temperatures, has greatly improved workability, is suitable for electronic component materials that require precision and a variety of functions, and has remarkable industrial effects such as being economically superior. be.

Claims (1)

[Claims] (1) AQ or A on at least a part of the surface of the Cu-based substrate
a In gold alloy coated materials, the substrate and A(] or AO
Between the alloy layers, Pd or RU with a thickness of 0.01 to 0.25μ
A (+ coated CI system electronic component monthly fee). A (I-coated Cu-based electronic component material) according to item 1.