JPS5994571A - Terminal for soldering - Google Patents

Abstract

PURPOSE:To provide a terminal which is inexpensive, is highly resistant to corrosion and has good wettability with solder by plating a thin film of Pd, via an Ni plating layer, on the soldering surface. CONSTITUTION:Ni is first deposited at about 1-2mu is an underlying surface on a terminal part 3 for soldering, thereby forming an Ni layer 4. A thin film of a Pd plating layer 5 is deposited at 0.01-0.10mu, more preferably 0.02-0.06mu on the surface of the layer 4. The conditions of an electrolyte for Pd plating in the stage of the above-mentioned deposition and for forming the same are set at about 0.5-1.0g/l Pd (metal), about 8.5-9.0pH (40 deg.C), about 35-45 deg.C temp. of plating soln., about 5-10A/dm<2> current density and about 4-5s/0.05mu time.

Description

[Detailed description of the invention] (a) Technical field of the invention The present invention relates to terminals for soldering electronic components.

(b) Background of the technology For wiring connections in device assembly or electrical connections between electronic components mounted on printed circuit board circuits and said circuits, connection methods such as winding connections and crimping connections that do not use solder are used. Although there are some, soldering is generally done using terminals.

In this case, it is important to distinguish between connecting parts such as terminal boards and connectors and general component terminals, and the component terminals used for connection have excellent acid resistance and corrosion resistance on the surface, and are especially suitable for storage of parts. It is required that there should be no deterioration during long-term storage of about a month.

The present invention is based on the demand for component terminals for soldering, and proposes a terminal plating method that has excellent corrosion resistance and good solder wettability.

(C) Problems with conventional technology The terminal material for forming is usually copper or brass, or for connectors etc., phosphor bronze, nickel silver, beryllium copper, etc., which have spring properties, are used, and this is formed into the desired shape to form the terminal body. Manufacture.

The terminal body is subjected to surface treatments such as tin plating, solder plating, and gold plating to satisfy the functions such as corrosion resistance.

For example, the road plating is inexpensive and has good plating workability, but has a problem with corrosion resistance. Further, in the solder plating 7, in order to obtain good solder wettability, it is necessary to apply a thick film plating with a thickness of about 5 to 10 microns (μm), but the plating takes a long time and is poor in mass productivity.

Furthermore, in the case of gold plating, for example, 1 to 2 (μm)
After applying nickel plating, the thickness is 0.05 (μm)
A thin film plating is formed. In the case of gold plating, sufficient solder wettability can be obtained with this thin film plating, but the problem is that the cost of forming terminals has increased due to the recent sharp rise in prices.

(d) Object of the Invention The object of the present invention is to solve the above-mentioned problems and to obtain a terminal surface with solder wettability equivalent to that of the conventional gold at low cost and with good mass production.

(e) Structure of the Invention The above object is achieved by providing a terminal for at least soldering, the surface of which is plated with a thin palladium film.

(f) Embodiments of the Invention Two embodiments of the present invention will be described in detail with regard to terminal surface treatment applied to connectors.

FIG. 1 is a perspective view showing a terminal of a connector for multi-wire cable connection, FIG. 2 is a perspective view showing the shape of a connector used therein, and FIG. 3 is a cross-section of a terminal portion for soldering according to the present invention. It is a diagram.

In the figure, 1 is an insulated housing, 2 is a soldered connector that connects a flat cable 4 to be assembled into the housing by crimping, and 3 is a soldered connector that is molded into the same body as the connector 2. This terminal portion is inserted into a connection hole of a printed circuit board (not shown) on which the connector is mounted and is soldered to the circuit board. The aforementioned connector 2 is shown in FIG.

FIG. 2A shows the connector 2 after basic machining, and FIG.

Connector 2 is a band-shaped spring material with good conductivity (phosphor bronze, etc.)
From (b), it is molded while maintaining continuity as shown in the figure.

(b) The lower portion 3 of the connector 2 in the illustrated state is the surface-treated portion for soldering.

Next, an embodiment of the soldering and surface treatment of the present invention will be described with reference to FIG.

The soldering terminal portion 3 of the molded connector 2 is coated with 1 to 2 μm of nickel as a plating base. This nickel layer 4 is coated with palladium (Pd), which is the plating metal that will be used later.
) to improve adhesion.

The surface of the nickel layer 4 is plated with a thin film of palladium N5 of 0.01 to 0.10 (/jm), preferably 0.02
~0°06 [μm] deposited.

What is the electrolyte composition of Pd plating and its production conditions?

Pd (gold M) io, 5-1.0 g/j2pH (4
layer 0°C); 8.5-9.0 Plating solution temperature; 35-45°C Current density: 5-10 A/dn? time
; 4-5 slo, 05 μm.

That is, if palladium (Pd) is deposited for 4 to 5 seconds at an electrolyte bath temperature of 40 DEG C., a plating thin film having a thickness of about 0.05 [mu]m per layer is formed on the terminal surface.

However, as Pd becomes thicker, its adhesion to the underlying surface decreases due to the relationship between its own pressure and the heat generated during soldering.
The plating thickness should be less than 0.1 [μm], 0.1 layer μm
] Good solder wettability even at thicknesses below.

Note that the minimum thickness of the palladium plating layer 5 must be at least 0.01 [μm] in view of peeling due to heat during soldering.

A series of connectors with the terminal surface plating described above.

In the post-process, the connector will be assembled with the insulating casing.

Next, the results of a deterioration test to verify the solderability of the connector terminals treated as described above will be described.

The target terminals are Pd plating By 0.02 and 0.06
(μm) Two types were prepared.

The deterioration conditions used in the test were as follows.

Conditions: 1100°C dump heat) (100% humidity).

1 hour condition■ 72 hour condition at a temperature of 40℃ and relative humidity of 90%■ Test sample that has gone through each of the above conditions for 16 hours at a drying temperature of 150"C. When evaluated, it was confirmed that all the results were good.

(g) Young fruit of the invention According to the soldering terminal of the invention described in detail above,
All expensive resources are saved, and a terminal with exactly the same performance can be realized at a lower cost (approximately 1/3 to 1/2). From this point of view, the present invention has great practical value.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a terminal of a multi-wire cable connector, and FIG. 2 is a perspective view showing the shape of a connector used therein. and FIG. 3 is a sectional view showing a terminal for soldering according to the present invention. 2nd z

Claims (3)

[Claims] (1) A terminal for soldering, characterized in that at least the soldering surface is coated with a thin film of palladium plating. (2) The soldering according to claim 1, wherein the thin film has a thickness of 0.01 to 0.10 (μm), preferably 0.02 to 0.06 (μm). is for terminal. (3) The soldering terminal according to claim 1, wherein the palladium plating thin film is formed on the soldering surface via a nickel plating layer.