JPH07326701A - Conductive material for electric-electronic part, lead frame and semiconductor integrated circuit using the same - Google Patents

Abstract

PURPOSE:To provided the title conductive material for electric.electronic parts, there layer plated lead frame and the semiconductor integrated circuit having an excellent solder wettability after heating step. CONSTITUTION:The three layer plated lead frame is provided with the base material 4 comprising copper or copper alloy as well as the first plated layer 3 comprising nickel or nickel alloy 0.10-1.50mum thick provided on this base material 4, the second plated layer 3 comprising silver 0.02-0.50mum thick provided on the first plated layer 2 and the third plated layer 1 comprising palladium or palladium alloy 0.01-1.00mum thick provided of this second plated layer 2. At this time, the crystal orientation index of the Pd surface (220) of this third plated layer 1 shall exceed 1.0.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a copper or copper alloy material as a base material, has a nickel or nickel alloy plating layer and a silver plating layer as a base, and has a palladium or palladium alloy plating layer as the outermost layer. More specifically, the present invention relates to a conductive material for electric / electronic parts, a lead frame and a semiconductor integrated circuit using the same, and more particularly to a three-layer plated structure having excellent solder wettability and workability after heating.

[0002]

2. Description of the Related Art Palladium has been widely used as a substitute for gold in conventional materials for electric and electronic parts. This is because palladium is unlikely to form an oxide film like gold,
This is because the electrical characteristics are excellent.

Palladium, which is harder than gold and has an advantage in electrical contacts and the like which are required to have wear resistance, has been put to practical use as a plating material for terminals.

Although it is not a lead frame,
No. 613. It is disclosed that a header or a can of a semiconductor device is provided with a palladium-silver alloy plating layer and the palladium-silver alloy is used as a substitute for gold.
This is said to be effective in reducing the cost, improving the corrosion resistance, heat dissipation and adhesiveness, and improving the characteristics of the semiconductor.

However, since silver plating causes discoloration and deterioration of electrical properties due to sulfurization and the like, sufficient consideration must be given to the addition method and control of the film structure. In the palladium-silver alloy plating layer described in the above publication, since the method of adding silver and the film structure have not been studied, a lead frame plated with both palladium and silver is based on the technology described in this publication. It could not be put to practical use.

[0006] In order to suppress discoloration of silver plating due to sulfidation or the like and deterioration of electrical characteristics, a technique of applying palladium plating on the surface has been proposed (Japanese Utility Model Publication No. 41-10577). This technology uses silver plating as an alternative to gold,
A base material for a power transistor in which palladium is plated on the surface of silver for improving the corrosion resistance of silver plating and controlling the flow of solder is described. However, the palladium-plated base material described in this publication cannot be applied to a lead frame because the silver plating layer has a large thickness and migration occurs.

On the other hand, silver elution (migration) occurs on the lead surface exposed from the sealing portion of the silver-plated component to the outside.
For prevention, a technique of forming a metal layer of nickel, tin, palladium, gold, tin or the like has been proposed (Japanese Patent Publication No.
-41139), in the technique described in this publication,
Since palladium and gold are expensive, the formation of a tin layer is preferred.

[0008] However, in this prior art, although silver elution preventing metal is externally plated, there is a risk of migration, and if the silver layer is made thin, diffusion of the copper material cannot be suppressed. The characteristics deteriorate. Therefore, silver plating cannot be used for the outer leads, and only the inner leads are partially plated.

However, a lead frame plated with both palladium and silver has not been put to practical use. This is because palladium has a problem that the solder wettability is deteriorated by heating in the assembly process, and silver plating has problems that the contact resistance and the migration property are low.

Japanese Utility Model Application Laid-Open No. 48-27756 proposes an integrated circuit in which the entire surface of a lead wire for a semiconductor integrated circuit is plated with palladium. Similarly to this
No. 358 and Japanese Patent Laid-Open No. 3-283556 propose a lead frame whose entire surface is plated with palladium. In these integrated circuits and lead frames,
It is intended to replace all gold and silver with palladium, but in this case, by receiving heat such as die bonding, wire bonding and curing,
There is a problem that solder wettability is reduced.

On the other hand, JP-A-4-171748 proposes a lead frame in which the surface of a palladium plating layer plated over the entire surface is thinly plated with gold in order to improve the deterioration of solder wettability due to heating. However, since gold is expensive, the method of providing this gold plating layer cannot meet the demand for low cost, and it is desired to develop a technique for improving the solder wettability of the lead frame after heating by a lower cost means. It was rare.

In recent years, with the miniaturization of electronic equipment and the progress of semiconductor packaging technology, the lead pitch has become narrower, and it is necessary to reliably bond such narrow-width leads. For this reason, in order to improve the bondability when the lead frame is mounted on the substrate after mounting the chip and sealing with resin,
External solder plating is applied to the leads prior to board assembly.

[0013] This external solder plating is high in cost and has been an obstacle to the consistency of processes in electric manufacturers. Therefore, in order to omit the external solder plating,
Palladium plating has begun to be reviewed. As a technique in which palladium plating is applied in order to omit the external solder plating, there is a technique disclosed in JP-A-63-2358.

As a conventional method for improving the solder wettability of a palladium plated lead frame after heating,
At least Ag-on the outer lead tip of each lead
Japanese Patent Laid-Open No. 63-3046 discloses a Pd-based alloy or an Ag-Sb-based alloy that is plated to eliminate the external solder plating and prevent the plating manufacturing process from becoming complicated.
54). However, since Ag and Pd have different electrochemical ionization tendencies, this alloy plating is difficult and there is a problem in bath stability. Moreover, the characteristics of Pd are required on the outermost surface, and it was difficult to put the Ag-Pd alloy plated into practical use.

[0015]

As described above, the exterior solder plating is not exposed to a heated atmosphere and its surface is not subject to changes (oxidation, diffusion, etc.) due to heat, that is, heat aging. The solder wetting time is good at 1 second or less. However, if it is plated in advance, it undergoes heat aging due to die bonding, wire bonding, curing or the like of the chip. In the conventional palladium plated material, the solder wettability was deteriorated after this thermal aging.

Although a patent application has been filed for a lead frame with palladium plating on a nickel base, palladium has a drawback that solder wettability after oxidation with heat and thermal aging is inferior to that of solder plating.

As described above, the conventionally well-known palladium-plated material has a poor solder wettability after heating, and the solder wettability of the semiconductor device after the finished product is inferior to that of the external solder plating. Therefore, it is desired that the solder wettability after heating is equivalent to that of the external solder plating.

Although the conventional patent has not examined the plating thickness, the relationship between the plating thickness and the characteristics is important nowadays when the bare bonding technology and the exterior solder plating have been developed. The characteristics change depending on the specified height. In order to make the silver plating as thin as possible and improve the migration property, it was essential to control the optimum plating thickness of each of palladium, silver and nickel.

Further, when the palladium layer is directly plated on the copper layer, the material copper diffuses on the palladium due to heating during chip mounting and resin encapsulation, which deteriorates various properties such as solderability. . Therefore, palladium is plated thickly or a nickel underlayer is provided between the copper material and the palladium plating.

However, either method deteriorates workability,
There is a problem in using as a lead frame material having stamping and bending workability.

Therefore, it is possible to perform plating after processing stamping or the like, but plating after stamping and partial plating have a problem of high plating cost.

There has been a demand for a technique that sufficiently satisfies the workability required for the lead frame and does not reduce the workability by palladium plating or nickel plating. The decrease in solder wettability after heating the nickel-plated palladium-plated lead frame is particularly noticeable at the interface between nickel and palladium. To omit the external solder plating, improve the adhesion between nickel and palladium. It is not known that this is necessary.

Known techniques including conventional palladium plating, for example, Japanese Patent Publication No. 63-49382 and Japanese Patent Laid-Open No. 63-
Although the structure of palladium is not mentioned at all in 2358 and JP-A-3-283556, it is difficult to apply it to lead frames and the like because palladium is famous as a metal that causes hydrogen absorption and cracks occur in the plating film. Was considered.

Even in the case of a palladium-plated lead frame, if the type of palladium plating solution, the plating conditions and the solution management method are different, the characteristics such as solder wettability are completely different, and it is difficult to cope with these conditions. This has hindered the practical use of the palladium-plated lead frame.

Recently, the development of ammonia-based palladium plating solutions has progressed, and palladium plating has come to be applied to lead frames, but it has not been clarified that its characteristics change depending on the structure of the palladium plating film. . Then, the relationship between the structure of the palladium plating film and the solder wettability after heating has been clarified, and a palladium plating film having excellent oxidation resistance after heating that can omit exterior solder plating has been desired.

The present invention has been made in view of the above problems, and is excellent in solder wettability after heating, and it is possible to omit the external solder plating. An object of the present invention is to provide a semiconductor integrated circuit using the.

[0027]

The conductive material for electric and electronic parts and the lead frame according to the present invention have a base material made of copper or a copper alloy and a thickness of 0.10 to 10 provided on the base material.
First made of 1.50 μm nickel or nickel alloy
A plating layer and a second plating layer formed on the first plating layer and made of silver having a thickness of 0.02 to 0.50 μm;
The thickness provided on the second plating layer is 0.10 to 1.
Third consisting of 00 μm palladium or palladium alloy
And a plating layer.

A semiconductor integrated circuit according to the present invention comprises a semiconductor element mounted on a three-layer plated lead frame,
And a wiring board on which the layer-plated lead frame is mounted.

[0029]

The operation of the present invention will be described below by taking a lead frame as an example. In the following description, palladium plating means palladium or palladium alloy plating, and nickel plating means nickel or nickel alloy plating, unless otherwise specified. As a result of the inventors of the present invention earnestly examining the practical application of the palladium plated material, the solder wettability and workability of the palladium plated material after heating are impaired when applying this to a lead frame or the like. There was found.

Therefore, in the present invention, in order to improve the solder wettability of the palladium-plated lead frame after heating, as a result of experiments and research on various undercoating, by providing a silver underplating layer, the solder wettability after heating was obtained. It has been found that the sex is extremely improved. The diffusion of copper as the base material is prevented by the underlying nickel plating layer, but is affected by the diffusion of nickel due to heating. However, as described above, the effect of nickel diffusion can be avoided and the palladium-plated lead frame can be effectively utilized by combining with the silver undercoat plating layer. With prior art palladium or palladium alloy plated leadframes that do not use silver underplating, it is extremely difficult to maintain solder wettability after heating to 250 ° C. for 3 hours.

The thickness of the third plating layer made of palladium or a palladium alloy is limited to 0.10 to 1.00 μm, because if it is thinner than 0.10 μm, the effect of maintaining solder wettability after heating is deteriorated. This is because the migration of silver cannot be suppressed, and even if plating is performed to a thickness of more than 1.00 μm, the solder wettability after heating is less affected and the cost is increased.

As described above, in the silver-underlying palladium-plated lead frame, one having excellent solder wettability, which enables omission of exterior solder plating, was obtained.
In the g2-layer plating, the base silver plating must be thickened to 1.00 μm or more.

In practice, the conventional silver plated material has a thickness of 1.0.
Silver plating of 0 μm or more was usually applied. However, the thickness of the silver plating layer is 1μ when it is subjected to heat aging due to chip bonding, wire bonding or curing.
Unless it is more than m, diffusion of copper from the material cannot be suppressed,
Yellowing occurred after heating. The solder-wettability of the yellow-colored one was also lowered.

In the case of performing multi-layer plating, if the thickness of the silver plating layer is increased, the cost becomes high and there is a risk of problems due to elution of silver. Therefore, the thickness of the silver plating layer is set to 1.00 μm or less. Is desirable. Therefore, in the present invention, nickel-plated Pd / A
A plating layer having a three-layer structure of g / Ni is provided.

The thickness of the silver plating layer is 0.02 to 0.50 μm.
The reason for limiting the thickness to m is that silver is indispensable for maintaining the solder wettability after heating, and for this purpose it is necessary to make the thickness 0.02 μm or more. This is because even if silver is plated, it has little influence on the solder wettability after heating, and there is a fear of a problem due to the elution of silver.

For the silver plating solution, it is desirable to use an ammonia-based plating solution when the silver plating solution may be mixed in the palladium plating solution due to the convenience of the plating process.

Further, the first plated layer made of nickel base or nickel alloy will be described. The workability of the lead frame material provided with the palladium or palladium alloy plating layer is determined by the workability of the underlying nickel or nickel alloy plating layer. The inventors of the present application have studied the possibility of omitting the underlying nickel or nickel alloy plating layer. However, if the first plating layer consisting of the underlying nickel or nickel alloy is not provided, the palladium or palladium alloy plating material is It was concluded that the diffusion of copper in the material may lower the basic properties such as solderability, and that a layer for diffusion prevention is essential. In this case, not only the pure nickel plating layer but also a nickel alloy plating layer containing one or more of cobalt, phosphorus, manganese, iron or the like may be used as the first plating layer as the diffusion preventing layer.

In order to improve the workability of the palladium-plated material, the inventors of the present invention changed the thickness of the underlying nickel plating layer and investigated the workability of this underlying nickel plating layer and the solder wettability after heating. As a result, it was found that in the three-layer plated lead frame of the present invention, it is not necessary to form a plated layer having a thickness of 1.50 μm or more as reported for the conventional nickel underplated layer. Further, it has been found that the bending workability of the lead frame product is sufficiently improved by limiting the thickness of the nickel undercoat layer to 1.50 μm or less. The thickness of the nickel plating layer is limited to 0.10 to 1.50 μm.
This is because if it is thinner than 0.10 μm, the effect of preventing the diffusion of copper in the material due to heating is small, and if it exceeds 1.50 μm, the bending workability required for the lead frame is deteriorated.

In this way, the lead frame material provided with the three-layer plating is obtained. Even if a gold layer is thinly formed on the surface after the palladium plating, or the surface is treated with an antioxidant, a rust preventive and a pinhole preventive, as is conventionally done for contact materials and terminals. good. Forming a thin gold layer increases costs, but the treatment is easy because it can be applied simply by immersing it in a commercially available gold plating bath.

In order to improve the adhesion between the nickel layer and the silver layer, the silver plating is preferably strike silver plating.

On the other hand, even with pure palladium plating, the solder wettability after heating varies depending on the type and composition of the bath and the plating conditions. That is, the palladium plating film having excellent solder wettability after heating has a high crystal orientation index on the Pd (220) plane. When the crystal orientation index of the Pb (220) plane is an ammonium chloride salt bath as a plating bath,
The higher the pH, the higher the pH, and the lower the plating current density and the bath temperature, the higher the pH. That is, when palladium plating is performed under conditions of pH of 8.5 or more, current density of 1 A / dm ² or less and bath temperature of 40 ° C. or less, a sufficiently high crystal orientation index of 1 or more is obtained.

In the present invention, it is preferable that the crystal orientation index of the Pd (220) plane on the outermost surface of the lead frame is 1 or more. This is because when the crystal orientation index is 1 or less, the solder wettability is rapidly reduced by heating. On the other hand, the crystal orientation of the palladium plating film affects the oxidation rate of palladium. By the technique of controlling the structure of this palladium plating film, a lead frame having excellent solder wettability after heating can be obtained.

However, only by controlling the crystal orientation of the palladium plating, it is difficult to set the solder wetting time to 1 second or less after heating, for example, after heating at 250 ° C. for 3 hours.
This is because the wettability of the solder is deteriorated due to the diffusion of the underlayer because the palladium plating is thin as well as the effect of oxidation of the palladium itself.

Palladium / silver / nickel 3 according to the invention
The layer-plated lead frame solves the problems that existed in the conventional noble metal-plated lead frame, and makes it possible to mount a completed semiconductor device onto a substrate without performing external solder plating. Further, since the thickness of the plating layer is set in an appropriate range, this three-layer plated lead frame is highly practical, and the present invention provides a lead frame having high solder wettability and high practical value.

The copper or copper alloy base material having this three-layer plating structure can be used as a conductive material for electronic and electrical parts such as contacts or terminals, and the lead frame having the above-mentioned three-layer plating structure can be integrated in a semiconductor. It can also be incorporated into a circuit.

[0046]

EXAMPLES Next, examples of the present invention will be described in comparison with comparative examples. FIG. 1 shows a third embodiment according to the present invention.
FIG. 2 is a sectional view of a semiconductor integrated circuit in which a lead frame 10 having a layered structure is incorporated, and FIG.
It is sectional drawing which shows a part of 0. As shown in FIG. 1, the outer leads of the lead frame 10 of this embodiment are partially joined to the wiring board 8 by the solder 7.
Further, in the lead frame 10, as shown in an enlarged scale in FIG. 2, a first plating layer 3 made of nickel or a nickel alloy is formed on the surface of a base material 4 made of copper or a copper alloy. A second plating layer 2 made of silver is formed on the first plating layer 3, and a third plating layer 1 made of palladium or a palladium alloy is formed on the second plating layer 2. And this lead frame 1
The semiconductor chip 5 is adhered onto the inner leads 0 of 0 by solder 7. The semiconductor chip 5 is connected to the wiring pattern of the outer lead by a bonding wire 6. The chip 7 and the inner leads are covered with a sealing resin 9 and protected from the outside air.

Next, an example and a comparative example will be described in which a lead frame used for connecting the semiconductor integrated circuit is manufactured, and the characteristics of the lead frame of the example of the present invention are compared with those of the conventional lead frame. .

A copper alloy plate of Cu-0.1Fe-0.03P-2Sn (thickness: 0.25 mm) was press punched to produce a lead frame base material. 0.50 μm thick semi-bright nickel plating was applied to the entire surface of the lead frame base material, then strike silver plating was performed for 5 seconds, and then 0.20 μm thick silver plating was applied by electroplating. Further, 0.50 μm palladium plating was applied to produce a three-layer plated lead frame.

This lead frame showed good solder wettability even after heating at 250 ° C. for 3 hours, and had good repeated bendability. Then, the manufacturing cost of this lead frame was low, and a lead frame of high practical value was obtained. Measuring method of plating thickness The thickness of each plating layer in production control was measured with a fluorescent X-ray film thickness meter. X for palladium, silver and nickel
The intensity of fluorescent X-rays peculiar to the element was measured by irradiating with a ray, and the thickness was obtained because the X-ray intensity was proportional to the number of atoms.

The plating thickness of the product was measured by a scanning Auger photoelectron spectrometer. That is, the distribution of palladium, silver and nickel in the thickness direction of the lead frame was measured by Auger photoelectron spectroscopy to determine the plating thickness.

The plating thickness is preferably measured by obtaining a cross section of the plating with a microtome and measuring the plating thickness. At the interface between the copper material and the nickel plating layer, 25
After heating at 0 ° C. for 3 hours, an alloy layer having a thickness of 0.1 μm may grow. However, under normal storage and use conditions, no change in properties has been observed due to the growth of intermetallic compounds between palladium, silver and nickel. In addition, even after heating, the presence of an intermetallic compound layer between palladium, silver and nickel is not recognized.

Even if an alloy layer is formed,
The plating thickness defined in the present specification includes the thickness of the alloy layer. Therefore, in the unlikely event that an alloy layer is formed, the alloy layer of silver and nickel is included in the thickness of the silver plating layer, and the alloy layer of palladium and silver is included in the thickness of palladium or the palladium alloy layer. The thickness of the plating layer thus obtained is shown in Table 1 below for Examples 1 to 5 of the present invention and Comparative Examples 1 to 9 outside the scope of the present invention.

[0053]

[Table 1]

Test Method for Evaluation of Solder Wettability The outer leads (thickness: 0.25 mm; width: 0.5 mm) of the lead frame plated as described above were exposed to 2
After heating at 50 ° C. for 3 hours, it was immersed in a 6/4 solder bath (60 wt% Sn-40 wt% Pb) at 230 ° C. for 10 seconds, and the solder wetting time (zero cross time) was measured.
An inactive flux was used and the immersion depth was measured at 4 mm.

Test Method for Evaluating Migration Resistance The outer leads (thickness: 0.25 mm; width: 0.5 mm) of the lead frame plated as described above are sandwiched with quartz glass at a distance of 1 mm, and the gap between the electrodes is filled with water drops, then 5 V The DC voltage was applied and the time until short circuit was measured. Then, it was judged that the migration resistance was good (◯) when the time until the short circuit was longer than the solder plating.

Repeated Bending Test In the repeated bending test, a load of 600 g was applied to the outer lead, 90 ° bending was repeated at a radius of 0.25 mm, and it was judged as good if it could be bent four times or more before breaking.

As shown in Table 1, all of Examples 2 to 5 exhibit good solder wettability after heating at 250 ° C. for 3 hours, and have good repeated bending property and migration resistance. Therefore, the external solder plating can be omitted, and the lead frame of this embodiment is a lead frame that enables integrated production by an electric manufacturer.

In Comparative Example 1, since the outermost surface was not coated with palladium, the surface was discolored and the solder wettability was lowered. Further, the silver plating layer alone has a problem of migration and cannot be used for the outer lead portion.

Comparative Examples 2, 3, 4, and 5 are lead frame materials plated with palladium. However, after heating at 250 ° C. for 3 hours, the solder wettability is deteriorated, and the characteristics are better than those of the exterior solder plated materials. Was inferior.

Further, in Comparative Examples 4, 6 and 8, since the palladium plating layer and the nickel plating layer were thick, cracks occurred in the bent portion, and repeated bending could not be performed.

In Comparative Examples 5, 7 and 8, the palladium plating layer was thin and there was a problem of silver migration.

In Comparative Example 9, the silver plating layer was thin, so 250
After heating at 0 ° C. for 3 hours, the solder wettability was deteriorated and the characteristics were inferior to those of the exterior solder plating material.

[0063]

[Table 2]

Measurement of Plating Orientation As for the plating orientation, the surface of palladium-plated lead frame was irradiated with X-rays, and the crystal orientation of palladium was measured from the obtained X-ray diffraction spectrum.

The crystal orientation of palladium varies depending on the type of plating bath, the pH of the plating bath, the plating temperature, and the plating current density. When these conditions are changed, the crystal orientation is changed and the solder wettability after heating is affected.

Although there is an acidic bath in the palladium plating bath,
An alkaline bath such as an ammine chloride salt bath is preferable, and it is important to control the pH to be high (pH is 8.5 or more) by adding aqueous ammonia. Further, by controlling the production conditions of the palladium plating film under conditions of low plating current density and bath temperature (current density of 1 A / dm ² or less, bath temperature of 40 ° C. or less), the characteristics of the palladium plating film are utilized. .

In Examples 6 and 7, since the crystal orientation index of the Pd (220) plane was 1.0 or more, good solder wettability was exhibited after heating at 250 ° C. for 3 hours, but Comparative Example 1
In Nos. 0 and 11, the crystal orientation index of the Pd (220) plane was smaller than 1.0, so that the oxidation of palladium proceeded after heating and the solder wettability was lowered.

[0068]

The palladium / silver / nickel three-layer plated lead frame according to the present invention has excellent solder wettability after heating, and the exterior solder plating can be omitted. Therefore, according to the present invention, not only the number of steps can be reduced, but also the reliability of the semiconductor can be improved. Furthermore, the outermost surface is a palladium layer, which has little deterioration in electrical characteristics, has excellent bonding properties, and has no migration problem. Further, the repetitive bendability is also improved. Therefore, according to the present invention, it is possible to provide a lead frame that enables integrated production in an electric manufacturer.

[Brief description of drawings]

FIG. 1 is a schematic view showing a cross-sectional structure of a package with a palladium / silver / nickel three-layer plated lead frame according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a sectional structure of an outer lead portion.

[Explanation of symbols]

 1; Palladium plating layer 2; Silver plating layer 3; Nickel plating layer 4; Copper-based substrate 5; Chip 6; Bonding wire 7; Solder 8; Wiring board 9; Sealing resin

Claims (5)

[Claims] 1. A base material made of copper or a copper alloy, a first plating layer made of nickel or a nickel alloy and having a thickness of 0.10 to 1.50 μm, which is provided on the base material, and a first plated layer.
The thickness provided on the plating layer is 0.02 to 0.50 μm
And a second plating layer made of silver, and a third plating layer made of palladium or a palladium alloy and having a thickness of 0.10 to 1.00 μm, which is provided on the second plating layer. Conductive material for electronic parts. 2. The Pd (220) on the surface of the third plating layer
The conductive material for electric / electronic parts according to claim 1, wherein the crystal orientation index of the plane is 1.0 or more. 3. A base material made of copper or a copper alloy, a first plating layer made of nickel or a nickel alloy and having a thickness of 0.10 to 1.50 μm, which is provided on the base material, and a first plated layer.
The thickness provided on the plating layer is 0.02 to 0.50 μm
Lead having a second plating layer made of silver and a third plating layer provided on the second plating layer and made of palladium or a palladium alloy having a thickness of 0.10 to 1.00 μm. flame. 4. Pd (220) on the surface of the third plating layer
The lead frame according to claim 3, wherein the crystal orientation index of the surface is 1.0 or more. 5. A semiconductor integrated circuit comprising: the semiconductor element mounted on the lead frame according to claim 3; and a wiring board on which the lead frame is mounted.