JP2002151838A - Pb-free solder connection structure and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Pb-free solder connection structure that has proper connection strength, a stable interface with time, and can secure whisker- resistance properties or the like, and to provide electronic equipment. SOLUTION: Sn-Ag-Bi-based solder that is a likely candidate as Pb solder is connected to an electrode, whose surface has an Sn-Bi-based layer. Bi concentration in the Sn-Bi layer should preferably be 1-2 wt.% for improved wetting properties. Furthermore, when highly reliable joint is required, by providing a Cu layer under the Sn-Bi layer, a connection section having sufficient interface strength is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Pb-free solder connection structure which is suitably connected to an electrode such as a lead frame by using a Pb-free solder alloy having low toxicity, and to an electronic device using the same. is there.

[0002]

2. Description of the Related Art Conventionally, in order to manufacture an electronic circuit board by connecting an electronic component such as an LSI to a circuit board such as an organic substrate, it is necessary to use S
An n-Pb eutectic solder, an Sn-Pb solder having a similar melting point in the vicinity of the Sn-Pb eutectic solder, or a solder alloy obtained by adding a small amount of Bi or Ag to these are used. These solders contain about 40% by weight of Pb. Each of these solder alloys has a melting point of almost 1
It is 83 ° C, and soldering at 220 to 240 ° C is possible. In addition, QFP (Quad Flat Pa
An electrode of an electronic component such as an LSI is generally formed by plating a 90% by weight Sn-10% by weight Pb (hereinafter abbreviated as Sn-10Pb) layer on the surface of a 42 alloy which is an Fe-Ni alloy. It is used regularly. This is because solder wettability is good, storage stability is good, and there is no problem of generation of whiskers.

[0003]

However, the above Sn-
Pb contained in the Pb-based solder is a heavy metal toxic to the human body, and the disposal of products containing Pb has a problem of pollution of the global environment and adverse effects on living organisms. Pollution of the global environment by this electric product is caused by elution of Pb by rain or the like from an electric product containing Pb left in the open. Pb elution tends to be accelerated by recent acid rain. Therefore, in order to reduce environmental pollution, Pb-free low-toxic Pb-free solder materials and Pb-free solder materials are used as substitutes for the Sn-Pb eutectic solders used in large quantities, and on component electrodes. Sn
A component electrode structure that does not contain Pb is required as a substitute material for the -10Pb layer. As a Pb-free solder material, Sn-Ag-Bi-based solder is a promising candidate from the viewpoints of low toxicity, material supply, cost, wettability, mechanical properties, connection reliability, and the like. In soldering, usually, 2
The connection is made by heating to around 20 to 240 ° C. to generate a compound between the electrode of the component and the substrate and the solder. Therefore, the interface formed differs depending on the combination of the solder material and the electrode material on the component side. To obtain a stable connection interface, an electrode material suitable for the solder is required.

[0004] An object of the present invention is to use a Sn-Ag-Bi-based Pb-free solder alloy that is less toxic to electrodes such as a lead frame and has a sufficient connection strength and a stable connection interface. An object of the present invention is to provide a Pb-free solder connection structure as described above. Another object of the present invention is to use a Sn-Ag-Bi-based Pb-free solder alloy having a low toxicity, to obtain a difference in thermal expansion coefficient between an electronic component and a substrate.
It has sufficient connection strength to withstand the stress generated in the solder connection part due to the warpage of the substrate during soldering or the warping of the probing test, handling, etc., and it is possible to obtain a stable interface over time. It is an object of the present invention to provide an electronic device which can be used. Another object of the present invention is to use a Sn-Ag-Bi-based low-toxic Pb-free solder alloy to secure sufficient wettability and to have sufficient connection strength, and to improve whisker resistance and the like. An object of the present invention is to provide a Pb-free solder connection structure and an electronic device that can be secured.

[0005]

In order to achieve the above object, the present invention provides a Pb-free solder comprising a Sn-Ag-Bi-based Pb-free solder connected to an electrode via a Sn-Bi-based layer. It is a free solder connection structure. Further, the present invention provides a method for manufacturing a Pb-free solder connection structure comprising the steps of:
The amount of Bi in the i-type layer is 1 to 20% by weight. Further, the present invention is characterized in that the Pb-free solder connection structure has a Cu layer between the Sn—Bi-based layer and the electrode. Also, in the present invention, in the Pb-free solder connection structure, the electrode may be a Cb-free solder connection structure.
It is characterized by being formed of a u material. Further, in the present invention, the electrode in the Pb-free solder connection structure,
It is a Fe-Ni-based alloy or a Cu-based lead. In addition, the present invention provides the Sn-Ag-Bi Pb-free solder in the Pb-free solder connection structure, wherein Sn is a main component, Bi is 5 to 25% by weight, and Ag is Ag.
Is 1.5 to 3% by weight, and Cu is 0 to 1% by weight.

The present invention is also an electronic device for electrically connecting a first electrode formed on an electronic component and a second electrode formed on a circuit board, wherein the first electrode is connected to the first electrode. Sn
An electronic device, wherein a first Bi-based layer is provided, and the first electrode provided with the Sn-Bi-based layer and the second electrode are connected by Sn-Ag-Bi-based Pb-free solder. .

[0007] Further, the present invention provides an electronic apparatus, comprising:
The amount of Bi in the n-Bi-based layer is 1 to 20% by weight. Further, according to the invention, in the electronic device, a Cu layer is provided between the Sn-Bi-based layer and the first electrode. Further, the present invention provides the electronic device, wherein the first electrode side of the Sn—Bi-based layer is Cu
It is characterized by being a material. Also, in the present invention, the first electrode in the electronic device may be formed of a Fe—Ni-based alloy or C
It is a u-type lead.

[0008] Further, the present invention provides an electronic apparatus, comprising:
The n-Ag-Bi-based Pb-free solder is characterized in that Sn is a main component and Bi is 5 to 25% by weight, Ag is 1.5 to 3% by weight, and Cu is 0 to 1% by weight. I do.
Further, the present invention provides a Pb-free solder connected to an electrode, which contains Sn as a main component, Bi is 5 to 25% by weight,
A Pb-free solder connection structure characterized by being a Sn-Ag-Bi-based material containing 1.5 to 3% by weight of g and 0 to 1% by weight of Cu.

As described above, according to the above configuration,
Sn-A with low toxicity for electrodes such as lead frames
Using a g-Bi-based Pb-free solder alloy, a sufficient connection strength can be obtained and a stable connection interface can be obtained.
Further, according to the above configuration, Sn-Ag-B with low toxicity is used.
Using i-based Pb-free solder alloy, stress generated in solder joints due to differences in thermal expansion coefficient between electronic components and boards, split board work after soldering, board warpage during probing test, handling, etc. It is possible to obtain an interface having a sufficient connection strength that can withstand the stress and stable over time. Further, according to the above configuration, Sn with low toxicity is used.
Using an Ag-Bi Pb-free solder alloy, for example, ensuring sufficient wettability at 220 to 240 ° C. to form a sufficient fillet and having a sufficient connection strength, and a whisker resistance etc. Can be secured.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described. The embodiment according to the present invention relates to a semiconductor device (L
SI) and other QFP leads and T
An electronic device is configured by connecting a first electrode formed by an SOP type lead or the like and a second electrode formed on a circuit board by using a Pb-free solder material having low toxicity. As the Pb-free solder connection structure, for example, there is a structure that is connected to the first electrode or the second electrode using a Pb-free solder material having low toxicity. As the less toxic Pb-free solder material, Sn-Ag-Bi-based solder is used. By the way, using a less toxic Sn-Ag-Bi-based Pb-free solder alloy, the difference in thermal expansion coefficient between electronic components and circuit boards, the work of split boards after soldering, or the warpage of boards during probing tests, It is necessary to have a sufficient connection strength to withstand the stress generated in the solder connection part due to handling or the like, and to obtain a stable interface over time.

[0011] Further, by using a Sn-Ag-Bi-based Pb-free solder alloy having low toxicity, the soldering temperature is set to 220 to 240 which is appropriate from the heat resistance of the circuit board and the electronic parts.
It is necessary to ensure sufficient wettability at ℃ and form a sufficient fillet shape to have sufficient connection strength. If the wettability is poor, a sufficient fillet shape is not formed and a sufficient connection strength cannot be obtained, or a strong flux is required, adversely affecting insulation reliability. In addition, whiskers are generated from the surface of the electrode formed by plating or the like, and short-circuiting between the electrodes occurs when the electrode grows. Therefore, it is necessary to ensure whisker resistance and the like.

As shown in FIGS. 1 and 2, in order to obtain a sufficient connection strength, the electrode structure according to the present invention has the following features.
The Sn-Bi-based layer 2 was applied to the surface of the electrode 1 composed of a lead. Next, selection of the electrode structure according to the present invention will be described. This selection was performed mainly based on the above-mentioned requirements by evaluating the connection strength, wettability, and whisker property. First, the results of examining the connection strength between the Sn—Ag—Bi-based solder and various electrode materials are shown. FIG. 3 shows an outline of the measuring method. As a substitute for the conventional Sn-10Pb layer, a material (S
n, Sn-Bi, Sn-Zn, Sn-Ag plating)
A model lead 4 provided on a lead which is an electrode formed of an Fe-Ni-based alloy (42 alloy) was prepared. In addition, evaluation was also made on a combination with conventional Sn-10Pb plating. Model lead 4 is 3m wide
m, length 38mm, soldering part length 22m
m is bent at a right angle. The plating thickness was about 10 μm for each composition. 8 of this model lead 4
2.2% by weight Sn-2.8% by weight Ag-15% by weight Bi
Using a Pb-free solder 5 (hereinafter abbreviated as Sn-2.8Ag-15Bi), it was soldered to a Cu pad (Cu electrode) 7 on a glass epoxy substrate 6 as a circuit board.
The size of the Cu pad (Cu electrode) 7 of the glass epoxy substrate 6 is 3.5 mm × 25 mm, and the size of the solder 5 is 0.1 mm.
It was supplied in a solder foil of mm × 25 mm × 3.5 mm. That is, the solder foil 5 was placed on the Cu pad 7 on the glass epoxy substrate 6, and the model lead 4 bent at a right angle was placed thereon. Soldering was performed in the atmosphere under the conditions of preheating at 140 ° C. for 60 seconds and a maximum temperature of 220 ° C. The flux used was a rosin-based flux containing chlorine. After soldering, it was washed with an organic solvent.
The tensile test was performed immediately after soldering, and after leaving at a high temperature of 125 ° C. for 168 hours in consideration of deterioration of the connection strength due to aging. Was left at 150 ° C. for 168 hours and then soldered. In the tensile test, the substrate was fixed, and the tip of the model lead was grasped and pulled vertically at a speed of 5 mm / min. At this time, the maximum strength and the constant tensile strength were evaluated as the fillet part strength and the flat part strength, respectively, for the model leads of each composition. This test is one for each condition
Performed 0 times and averaged.

FIG. 4 shows the results of evaluation of the fillet strength of model leads of each composition. In general, plastic package components such as QFP-LSI require a fillet strength of about 5 kgf or more in consideration of the difference in thermal expansion coefficient of the printed circuit board. Thus, a model lead in which a Sn-Bi-based layer other than Sn-23Bi containing 23% by weight of Sn and Bi is applied on a Fe-Ni-based alloy (42 alloy) has a fillet strength of 5 kgf or more. Although it was obtained, it was found that a sufficient connection interface could not be obtained in the case of the Sn—Zn, Sn—Ag, and Sn—Pb layers. In addition to this, Ni plating of about 2 μm was applied on the 42 alloy, and further, Au plating, Pd plating, and Pd plating were further subjected to A plating.
Three types of u-plated model leads were prepared, soldered in the same manner, and the interface strength was examined. As shown in FIG. 4, sufficient fillet strength was not obtained. Therefore, it was found that it was necessary to apply a Sn-Bi-based layer on the lead as the electrode.

Among the model leads of each composition subjected to the above tensile test, Sn-Bi having a sufficient interfacial strength was obtained.
Sn-2.8Ag-
The wettability to 15Bi solder was examined by the meniscograph method. The flux used was weak in activity in order to examine the wettability. The test piece is one of the above model leads.
cm. The test conditions for the wettability were as follows: the solder bath temperature was 220 ° C., the immersion speed was 1 mm / min, the immersion depth was 2 mm, and the immersion time was 20 seconds. The later load was defined as a wet load. In addition, the wettability of the lead immediately after plating was
Two kinds of leads were left for 168 hours at ℃. The measurement was performed 10 times for each condition, and the average was taken.

The wetting time and wetting load of each composition are shown in FIGS. From the results of the wetting time shown in FIG. 5, the higher the Bi concentration, the better the wettability of the Sn—Bi-based plating lead in the initial stage of plating. However, when left at 150 ° C. for 168 hours, Bi contained 1% by weight. It was found that the wettability deteriorated at less than 23% by weight and at 23% by weight. In the case where Bi is less than 1% by weight, as shown in FIG. 6, although the wetting load was secured, it can be said that the wetting became difficult because the wetting time was deteriorated. Therefore, it was found that, in order to obtain sufficient wettability, the amount of Bi is preferably 1 to 20% by weight among the Sn-Bi-based layers.

Further, in the case of connection between materials having a large difference in thermal expansion coefficient or use in an environment having a large temperature difference, stress generated at the interface becomes large. Must have a connection strength of about 10 kgf or more. Therefore, looking at FIG.
It was found that if the Sn-Bi-based layer was directly applied to the i-based alloy (42 alloy), a fillet strength of 10 kgf or more could not be obtained. This is probably because the compound layer at the interface was not sufficiently formed. Therefore, in order to increase the reactivity with the solder at the interface, an Fe—Ni alloy (4
2 alloy) on which a Cu plating layer having an average of about 7 μm and an Sn—Bi-based plating layer were applied thereon, and the interface strength was measured. The results of the strength of the fillet portion at this time are also shown in FIG. 7 when there is no Cu layer. Except when the Bi amount is 23% by weight, a connection strength of 10 kgf or more is obtained, and The effect was confirmed. In addition, by adopting this electrode structure, as shown in FIG.
Eutectic solder Sn-10Pb directly on 42 alloy lead
The interface strength immediately after soldering, which was obtained in the conventional case of soldering to the layered lead, was at least about 12.1 kgf. Further, as shown in FIG. 8, by applying a Cu layer under the Sn-Bi layer, the flat portion strength could be improved. Here, as for the Cu layer, when a 42 alloy lead frame is used, the Cu layer may be applied on the 42 alloy as described above. However, when a Cu-based lead frame is used, the Cu layer may be used as it is. Alternatively, another element may be added to the lead frame material in order to improve the rigidity. Therefore, a Cu layer may be further formed to eliminate the influence. The wettability of the model lead provided with the Cu layer is shown together in FIGS. 5 and 6. However, there is almost no influence of the Cu layer. The wettability has deteriorated,
At 1 to 20% by weight, sufficient wettability could be obtained. 7 and 8 are Sn-2.8Ag-15Bi.
Was used, but a system with a small amount of Bi, for example, Sn-2Ag-
Even in the case of 7.5 Bi-0.5 Cu, an effect of improving the interface strength can be obtained by adding a Cu layer as a base.

The above-mentioned Sn—Bi-based layer and Cu layer are not limited to plating, but can be formed by dipping, vapor deposition, roller coating, or coating with metal powder. As described above, in order to investigate the reason different depending on the electrode material, the cross section of the connection portion was polished, and the state of the interface was examined. Further, the peeled surface of the sample subjected to the tensile test was observed by SEM. The results of this representative combination will be described. First, FIG. 9 shows an observation result when a lead in which Sn-10Pb plating is directly applied to a conventionally used Fe-Ni-based alloy (42 alloy) is joined with Sn-Ag-Bi-based solder. In this combination, Pb and Bi formed a compound at the interface and gathered, and the separation occurred at the interface between the 42 alloy and the solder. Further, Sn was thinly detected on the surface of the 42 alloy of the peeled lead, and it is considered that Sn in the solder formed a compound with the 42 alloy of the lead. Therefore, it is considered that the connection area between Sn and the 42 alloy was reduced due to the above-mentioned compound of Pb and Bi gathering at the interface, and the connection strength became extremely weak.

Next, Sn-10Pb plating is performed on Sn-4B.
FIG. 10 shows the observation results when the plating was changed to i-plating.
The compound layer formed at the interface was thin, and peeling also occurred at the interface between the 42 alloy and the solder. However, Bi remains a granular crystal and does not cause a decrease in the connection area between Sn and the 42 alloy as much as in the case of Sn-10Pb.
It is considered that a connection strength of gf or more could be obtained.
At this time, the compound layer was found to have an S
It was an n-Fe layer. Further, FIG. 11 shows an observation result when a Cu layer was formed under the Sn-4Bi layer, and it was found that a thick compound layer of Cu and Sn was formed at the interface. The peeling occurred at the interface between the compound layer and the solder or in the compound layer. The peeled surface was almost flat in the case where the Sn-Bi layer was formed directly on the 42 alloy lead in FIG. 10, but was uneven when the Cu layer was present. Therefore, it is considered that such a difference between the peeled surfaces has led to an improvement in the interface strength.
In addition, the same result was obtained also with another composition of the Sn-Ag-Bi solder based on the above examination results.

The occurrence of whiskers was examined with respect to the model leads having the above-mentioned respective compositions. The generation of whiskers was observed on the surface of the model leads plated with Sn-Zn.
It has been conventionally said that Sn plating has a problem in whisker properties. However, no whisker was observed in the Sn—Bi-based layer, and there was no problem with whisker resistance. Therefore, according to the electrode structure of the present invention, S
For n-Ag-Bi solder, connection strength, wettability,
It is possible to obtain a connection part having excellent isker resistance.

Regarding the solder material, the main component is Sn and B
The reason why the Sn-Ag-Bi-based solder containing i of 5 to 25% by weight, Ag of 1.5 to 3% by weight and Cu of 0 to 1% by weight is selected is that the solder having a composition within this range is 220%. ~ 240
° C, and has almost the same wettability to Cu as Sn-Ag eutectic, which has been proven in the past, and
This is because it has sufficient reliability at high temperatures. That is, S
The n-Ag-Bi solder has a portion (ternary eutectic) where Bi is about 10% by weight or more and melts at around 138 ° C., which may affect the reliability at high temperatures. The eutectic precipitation amount is suppressed to a level that does not cause a practical problem, and
High temperature strength at 5 ° C is also ensured. Therefore, a practical and highly reliable electronic device can be obtained by soldering the above-mentioned electrode using the solder having this composition.

[0021]

Embodiment 1 FIG. 1 shows a sectional structure of a lead for a QFP-LSI. This shows a part of the cross-sectional structure of the lead, which is a Fe-Ni alloy (42 alloy).
An Sn—Bi-based layer 2 is formed on a lead 1 which is an electrode of the present invention. This Sn—Bi-based layer 2 was formed by plating, and the thickness was about 10 μm. The Bi concentration in the Sn—Bi plating layer was 8% by weight. The above-mentioned QFP-LSI having this electrode structure is formed by Sn-2.8Ag-15Bi.
It was soldered to a glass epoxy substrate, which is a circuit board, using -0.5Cu solder. Soldering temperature up to 2
The temperature was set at 20 ° C., and a nitrogen reflow furnace was used. As a result, a connection portion having sufficient connection strength was obtained. Similarly, Sn-2Ag-7.5Bi-0.5C
Using a u solder, the glass epoxy substrate was reflowed at 240 ° C. in the air. Reflowed joints are particularly reliable at high temperatures.

[0022]

Embodiment 2 FIG. 2 shows a sectional structure of a lead for TSOP. This also shows a part of the cross-sectional structure of the lead, in which a Cu layer 3 is formed on a lead 1 which is an electrode of an Fe-Ni alloy (42 alloy), and an Sn-Bi layer 2 is formed thereon. Have been. The Cu layer 3 and the Sn—Bi-based layer 2
Was formed by plating. The thickness of the Cu layer 3 was about 8 μm, and the thickness of the Sn—Bi-based plating layer 2 was about 10 μm. The Bi content in the Sn—Bi plating layer is 5% by weight. Since TSOP has high rigidity of the lead, the heat generated by the component itself during actual operation, and when used at a high temperature, the stress generated at the interface becomes larger than that of the QFP-LSI. In such a case, it is necessary to form an interface having sufficient interface strength to withstand this interface stress, and the Cu layer 3 is effective under the Sn-Bi-based layer 2.

This TSOP is printed on a printed circuit board using Sn-Ag.
-Soldering was performed using a Bi-based solder in a vapor reflow furnace, and a temperature cycle test was performed. Test condition is -55 ° C
30 minutes, 1 hour / 1 cycle at 125 ° C. for 30 minutes, and
Under two conditions of 0 ° C. for 30 minutes and 90 ° C. for 30 minutes, 1 hour / 1 cycle, cross sections were observed after 500 cycles and 1000 cycles, and the state of occurrence of cracks was examined. This is 4
2 Compared to a case where the same size TSOP having a lead in which a Sn-10Pb layer is formed directly on an alloy lead was soldered with Sn-Pb eutectic solder, -55 ° C / 1
Cracks were generated earlier in the 25 ° C. temperature cycle, but were not particularly problematic in the 0 ° C./90° C. temperature cycle, and a practically sufficient connection interface was obtained.

[0024]

Embodiment 3 The electrode configuration of the present invention can be applied to an electrode on a substrate. For example, a solder coat is effective to improve the solderability of a board, but conventionally, a solder coat is used.
An n-Pb solder, particularly a Pb-containing solder such as a Sn-Pb eutectic solder is used. For this reason, the Sn-Bi layer of the present invention can be used to make the coating solder Pb-free. In addition, since the electrodes of the substrate are usually formed of Cu, a sufficient connection strength can be obtained when Sn-Ag-Bi-based solder is used. An example in which this configuration is applied will be described below. A Sn pad of about 5 μm is formed on a Cu pad (Cu electrode) on a glass epoxy substrate which is a circuit board.
An 8 Bi layer was made with a roller coat. Since this solder layer was formed, the wettability to the substrate was improved, and the connection strength was also improved.

[0025]

According to the present invention, there is an effect that an electrode structure suitable for Sn-Ag-Bi-based solder which is excellent as a Pb-free material can be realized. Further, according to the present invention, Sn which is less toxic to electrodes such as a lead frame is provided.
The present invention has the effect of realizing a Pb-free solder connection structure having sufficient connection strength and a stable connection interface using an Ag-Bi-based Pb-free solder alloy. In addition, according to the present invention, the less toxic S
Using an n-Ag-Bi-based Pb-free solder alloy, the difference in the coefficient of thermal expansion between the electronic components and the board, the work of the split board after soldering, or the warpage of the board during the probing test, handling, etc. This has the effect of providing an electronic device having a Pb-free solder connection structure that has a sufficient connection strength to withstand the stress generated in the Pb-free solder connection structure and can obtain a stable interface over time.

Further, according to the present invention, Sn having low toxicity is used.
Using an Ag-Bi Pb-free solder alloy, for example, ensuring sufficient wettability at 220 to 240 ° C. to form a sufficient fillet and having a sufficient connection strength, and a whisker resistance etc. Can be secured. Further, according to the present invention, by soldering the electronic component with Sn-Ag-Bi solder, an interface having a sufficient connection strength can be obtained, and practically sufficient wettability can be secured. . There is no problem with whisker properties. Therefore, environmentally friendly Pb-free electrical products are replaced with the same equipment as before,
An effect that can be realized by using the process is achieved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a sectional structure of a lead for a QFP-LSI according to the present invention.

FIG. 2 is a diagram showing a cross-sectional structure of a TSOP lead according to the present invention.

FIG. 3 is a schematic explanatory view of a connection strength evaluation test method.

FIG. 4 is a view showing evaluation results of fillet strength of various metallized leads according to the present invention.

FIG. 5 is a diagram showing the results of evaluating the wetting time of various metallized leads according to the present invention.

FIG. 6 is a diagram showing the results of evaluating the wetting load of various metallized leads according to the present invention.

FIG. 7 is a view showing evaluation results of fillet strength when a Cu layer according to the present invention is formed.

FIG. 8 is a diagram showing evaluation results of flat portion strength when a Cu layer according to the present invention is formed.

FIG. 9 shows a conventional Fe—Ni alloy (42 alloy) with Sn—
It is a figure which shows the observation result of the interface with the lead which performed 10Pb plating, (a) is a figure which shows a cross section, (b) is a figure which shows the peeling part about the lead side and the solder side.

FIG. 10 shows an Fe—Ni alloy (42 alloy) according to the present invention.
5A and 5B are diagrams showing observation results of an interface with a lead plated with Sn-4Bi, wherein FIG. 5A is a diagram showing a cross section, and FIG. 5B is a diagram showing a peeled portion on a lead side and a solder side.

FIG. 11 shows an Fe—Ni alloy (42 alloy) according to the present invention.
Showing the results of observation of the interface between the Cu layer and the lead on which Sn-4Bi plating has been applied, (a) showing the cross section, (b) showing the peeled portion, and the lead side and the solder side. FIG.

[Explanation of symbols]

1. Lead (electrode) of Fe-Ni alloy, 2. Sn-Bi
System layer, 3 ... Cu layer, 4 ... Model lead, 5 ... Solder, 6
... Glass epoxy substrate, 7 ... Cu pad (Cu electrode)

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hiroaki Okuhira 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Hitachi, Ltd.Production Technology Laboratory (72) Inventor Toshiharu Ishida 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Inside Hitachi, Ltd.Production Technology Laboratory (72) Inventor Tetsuya Nakatsuka 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside Hitachi Ltd.Production Technology Laboratory (72) Inventor Yoshiharu Inaba Gojomihoncho, Kodaira-shi, Tokyo No. 20-1, Hitachi Semiconductor Co., Ltd. Semiconductor Division (72) Inventor Asao Nishimura 5-2-1, Kamimizu Honcho, Kodaira-shi, Tokyo F-term, Hitachi Semiconductor Co., Ltd. F-term (reference) 4K024 AA09 AA21 AB01 AB02 BB11 BB12 GA14 4K044 AA02 AA06 AB02 BA06 BA10 BB01 BB03 BC08 CA11 CA13 CA14 CA15 CA18 CA53 5E319 BB01 CC22 GG03 </ S> </ s> </ s>

Claims (14)

[Claims] A substrate and a surface layer of Sn-about (1-2)
0) An electronic apparatus, wherein a semiconductor device in which a weight-% Bi-based layer is directly formed on a Cu-based lead is connected using a lead-free solder material. 2. A semiconductor device in which a substrate and a Sn-approximately (1 to 20) wt% Bi-based plating layer serving as a surface layer formed on a Cu-based lead without intervening another plating layer are formed of lead. Electronic equipment characterized by being connected using a free solder material. 3. The method according to claim 1, wherein the substrate and Sn-about (1-2)
0) An electronic apparatus wherein a semiconductor device in which a weight-% Bi-based layer is directly formed on an Fe—Ni-based alloy lead is connected using a lead-free solder material. 4. A semiconductor device comprising: a substrate; and a Sn-approximately (1-20) wt% Bi-based plating layer serving as a surface layer formed on an Fe--Ni-based alloy lead without intervening another plating layer. Wherein the electronic device is connected using a lead-free solder material. 5. The electronic device according to claim 1, wherein said lead-free solder material contains Bi. 6. The electronic device according to claim 5, wherein said lead-free solder material having Bi is a Sn-Ag-Bi-based free solder material. 7. The electronic device according to claim 1, wherein said semiconductor device is a TSOP type semiconductor device. 8. A substrate, and Sn-approximately (1-2) serving as a surface layer
0) A method for manufacturing an electronic device, wherein a semiconductor device in which a weight-% Bi-based layer is directly formed on an Fe-Ni-based alloy lead is soldered using a lead-free solder material. 9. A semiconductor device comprising: a substrate; and a Sn-approximately (1-20) wt% Bi-based plating layer serving as a surface layer formed on a Fe—Ni-based alloy lead without intervening another plating layer. Using a lead-free solder material. 10. A substrate and a surface layer of Sn-about (1-2)
0) A method for manufacturing an electronic device, wherein a semiconductor device in which a weight-% Bi-based layer is directly formed on an Fe-Ni-based alloy lead is soldered using a lead-free solder material. 11. A semiconductor device comprising: a substrate; and a Sn-approximately (1-20) wt% Bi-based plating layer serving as a surface layer formed on an Fe--Ni-based alloy lead without intervening another plating layer. Using a lead-free solder material. 12. The method for manufacturing an electronic device according to claim 8, wherein said lead-free solder material contains Bi. 13. The method for manufacturing an electronic device according to claim 12, wherein the lead-free solder material having Bi is Sn.
-A method for manufacturing an electronic device, wherein the method is a Ag-Bi-based free solder material. 14. The method for manufacturing an electronic device according to claim 8, wherein the semiconductor device is a TS.
A method of manufacturing an electronic device, which is an OP type semiconductor device.