JP2000022063A - Electronic component and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic component which is free from Pb, hardly oxidized, and excellent in solderability by a method wherein a rosin-containing resin film is formed on the metal film of the electrode terminals of the electronic component. SOLUTION: A rosin-containing resin film 7 is formed on the metal film 6 of the electrode terminals 4 of an electronic component. The resin film 7 is formed through a method where an electronic component is dipped into a solution which is composed of alcohol such as methanol, ethanol, or isopropyl alcohol and rosin dissolved in it or the vapor of solution is made to blow against the electronic component, and then the electronic component is thermally treated at a temperature at which alcohol is evaporated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode terminal of an electronic component, and more particularly to an electronic component with improved rust prevention and solderability on a metal film of the electrode terminal, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, electrode terminals of electronic parts are, for example,
As described in Surface Technology Vol. 48, page 1000 (1997), an alloy of Pb and Sn, a so-called solder film, is formed on electrode terminals by electroplating or dipping to facilitate soldering to electronic equipment. I was Recently, due to the toxicity of lead, the study of Pb-free solder (Nikkei Electronics,
No. 635, p. 92, 1995).
Pd-plated PP that eliminates the need for solder on electrode terminals
F-Technology (1st Surface Properties Study Group Textbook, Page 1, Surface Technology Association Kansai Branch, 1996) has also been developed.

Further, an electrode of a metal-sealed semiconductor device is coated with a polyethylene oxide film (Japanese Patent Laid-Open No. 55-115).
No. 350), a method of coating an electrode terminal with an antioxidant film which decomposes and sublimates at the soldering temperature is also known (Japanese Patent Application Laid-Open No. 56-56).
-98849).

[0004]

However, the coating formed on the electrode terminals is oxidized in the manufacturing process of the electronic component even for Pd before mounting as the electronic component, and the solderability is deteriorated.

[0005] In the future, it is inevitable that the coating of the electrode terminal will shift to solder containing no Pb, and since the coating is more easily oxidized than Pb / Sn, it is expected that solderability will be difficult.

An object of the present invention is to solve the above-mentioned conventional problems, and to provide an electronic component which does not contain Pb and which is not easily oxidized and has good solderability on a metal film of an electrode terminal of the electronic component, and a method of manufacturing the same. With the goal.

[0007]

SUMMARY OF THE INVENTION In order to achieve this object, the present invention is to form a film on a metal film formed on an electrode terminal for delaying oxidation of the film. That is, after forming a metal film on the electrode terminal of the electronic component, another film is formed on the metal film, and the film prevents oxidation of the metal film. It is needless to say that the coating to be formed on the metal coating is not only for the purpose of preventing oxidation, but also has a flux effect at the time of soldering. It is.

The formation of a film containing rosin on the metal film for preventing the metal film of the electrode terminal from being oxidized is performed, for example, by dissolving rosin in an aliphatic lower alcohol such as methanol, ethanol or isopropyl alcohol, and immersing the resin in the solution. This can be achieved by performing a heat treatment at a temperature at which the alcohol evaporates after spraying or spraying the vapor of the solution.

The thickness of the coating is estimated to be 5 nm to 50 nm, although it depends on the processing and storage conditions of the electrode terminals after coating. This is because if the coating is thin, there is no effect of preventing oxidation, and if the coating is thick, the electrode terminal is separated from the metal coating by processing. If the thickness is 50 nm or less, the rosin film is mechanically and firmly adhered due to the unevenness of the surface of the metal film, and is hardly peeled off even with contact, friction or temperature change. The thickness of the coating can be controlled by changing the amount of pine tar or rosin dissolved in lower alcohol. For example, 10n of the present invention
If you want to obtain a thickness of about m, for example, 1 g of rosin
May be immersed in a solution in which is dissolved in 500 cc of ethanol.

According to this structure, an electronic component having an electrode terminal which does not contain Pb and is not easily oxidized and has good solderability is obtained on the metal film of the electrode terminal of the electronic component.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention prevents oxidation of a metal film by forming a thin film typified by pine tar, rosin or abietic acid salt which is a main component thereof on the metal film of an electrode. The feature is that it is used as a flux at the time of mounting.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of the present invention using a resin-sealed semiconductor device according to the present invention as an example. That is, a semiconductor chip 2 is adhered on a lead frame 1 having a thickness of 3 μm and plated with nickel on a Cu material, and a thin metal wire 3 is used to connect the chip 2 to a region connected to an external electrode 4. Thereafter, after sealing with a molding resin 5 and electrode terminal (lead) processing, a 10 μm thick Bi / Sn (5/90% by weight) coating 6 was obtained on the electrode terminals by plating. Thereafter, the entire semiconductor device having external electrode terminals is dipped in a 0.2% by weight ethanol solution of rosin for 10 seconds to form a rosin coating 7,
Dry at 00 ° C for about 10 minutes.

Since the rosin coating 7 covers the entire electronic component including the surface of the molding resin, when marking is performed on the upper surface of the semiconductor resin with a laser or the like, characters with good contrast are formed.

As shown in FIG. 2, if the rosin coating 7 is at least coated on the mounting surface (lower part of the lead) to be soldered at the time of mounting, lead-free soldering having an oxidation preventing effect can be performed. or,
As shown in FIG. 3, only the lead portion may be covered by dip coating.

In this embodiment, an example in which rosin is dissolved in ethanol has been described. However, in addition to rosin, rosins such as pine tar and organic acid salts containing abietate such as methyl abietate as a main component are used. The same effect can be obtained by using an aliphatic lower alcohol such as methanol or isopropyl alcohol. As a method of applying rosin instead of dip, a solution spraying method can be used.

As an example of the effect of the present invention, the solderability of an electrode terminal having a rosin coating formed on a 10 μm thick Bi / Sn (5/90% by weight) plating described in the embodiment will be described.
After the film formation, high-temperature and high-humidity treatment (8
5 ° C, 85%, 32 hours) and high temperature treatment (150 ° C,
After 32 hours), a soldering test was carried out. The results are shown in Table 1 in comparison with A) a case where no rosin coating was formed and B) a case where polyethylene oxide was applied. Solderability was determined by Ag / Bi / Sn (3.
5 / 7.5 / 89% by weight) Good when the solder wetting area when immersed in the bath for 3 seconds is> 95%.
<80% was judged as x. The number in the parentheses in the table indicates the number of defects / the number handled. As is clear from the table, the electrode terminals of the semiconductor device obtained according to the present invention have good solderability even under severe processing.

[0017]

[Table 1]

The evaluation result of the conventional lead solder is as follows.
The solderability of the electrode terminal having a rosin coating formed on Pb / Sn (10/90% by weight) plating with a thickness of 10 μm (230
The rosin coating treatment is performed in the same manner as in Table 1 even in a Pb / Sn (10/90% by weight) bath at 3 ° C. for 3 seconds, so that the solderability is improved even when severe treatment is applied. It was good.

As described above, good soldering even in severe processing means that it can be used anywhere in the world, and also has the effect of promoting the introduction of Pb-free solder which is desired from an environmental point of view.

[0020]

As described above, according to the present invention, after a metal film is formed on an electrode terminal of an electronic component, an organic material represented by pine tar, rosin, or abietic acid salt which is a main component thereof is formed on the metal film. The acid salt is dissolved in an aliphatic lower alcohol such as methanol, ethanol, or isopropyl alcohol, immersed in the solution or sprayed with the vapor of the solution, and then heat-treated at a temperature at which the alcohol evaporates to form a thin film. By preventing the metal film from being oxidized by the film, it is possible to provide an electronic component having good solderability and a method for manufacturing the same.

[Brief description of the drawings]

FIG. 1 is a sectional view of an electronic component (semiconductor device) obtained according to an embodiment of the present invention.

FIG. 2 is a sectional view of an electronic component (semiconductor device) obtained according to an embodiment of the present invention.

FIG. 3 is a sectional view of an electronic component (semiconductor device) obtained according to an embodiment of the present invention.

[Explanation of Signs] 1 Lead frame 2 Semiconductor chip 3 Fine metal wire 4 Area connected to external electrode 5 Resin for sealing 6 Metal coating on electrode terminal 7 Rosin coating

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[Procedure amendment]

[Submission date] September 21, 1999 (September 9, 1999
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

In order to achieve this object, the present invention is to form a film on a metal film formed on an electrode terminal for delaying oxidation of the film. That is, after forming a lead-free metal coating on the electrode terminals of an electronic component, the metal coating
A resin film containing a rosin having a thickness of 5 to 50 nm is formed on the film, and the film prevents oxidation of the metal film. It is needless to say that the coating to be formed on the metal coating is not only for the purpose of preventing oxidation, but also has a flux effect at the time of soldering. It is.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazuhiro Aoi 1-1, Komachi, Takatsuki-shi, Osaka Matsushita Electronics Co., Ltd. F-term (reference) 4K062 AA01 BB06 BC01 CA02 CA05 FA09 5F067 AA00 DC11 DC12 DC16 DC18 DD18 DD05 DE01 DF01 EA04

Claims (7)

[Claims] 1. An electronic component having a resin coating containing at least rosin on an external electrode terminal on which a metal coating for soldering is formed. 2. The electronic component according to claim 1, wherein the metal coating is a metal coating for lead-free soldering and containing at least Pd. 3. The electronic component according to claim 2, wherein the resin component is an external electrode terminal having a thickness of 50 nm or less. 4. An electronic element is resin-encapsulated together with a lead.
The electronic component according to claim 1, wherein a resin film containing at least rosin is provided continuously to the external electrode terminal of the lead and the resin-encapsulated surrounding portion. 5. A method for manufacturing an electronic component, comprising: providing a resin film containing rosin even if not on an external electrode terminal; and heat-treating the external electrode terminal. 6. An electronic component, wherein the step of providing a resin film includes a step of immersing the external electrode terminal in an alcohol solution containing at least rosin or applying the alcohol solution containing at least rosin to the external electrode terminal. Manufacturing method. 7. The method for producing an electronic component according to claim 6, wherein an alcohol solution having a concentration of rosin dissolved in the alcohol of 0.1 to 2% by weight is used.