〉〉 Electronics & Automotive Systems〉〉New Products

Roughening Copper Plating With High Resin Adhesion

INTRODUCTION
1.1.INTRODUCTION
A semiconductor component, such as the LED, the transistor, the capacitor, is expected a market expansion
due to its deployment for in-vehicle use. Based on thisdeployment, a high reliability is required from the pointof view of a use in a high load environment or a temperature degradation due to increasing of power density,and the improvement of the packaging technology isprogressing1).
The lead frame of the semiconductor component isrequested not only to secure the electric connection butalso a high resin adhesion is required from the point ofview of securing an excellent reliability in a high load environment. A mechanical bonding with an anchor effect iseffective for the adhesion between the lead frame and theresin2), and in order to improve this adhesion, the etchingor the polishing on the material surface or the forming ofa nickel-plating film with a large surface roughness (thereafter called nickel roughening)3) are available, it is furthermore needed for more improvement in the reliability of theautomotive component under the high load environment.
Furukawa electric developed the copper plating on theTable 1

surface of the lead frame with the granular surface roughness (thereafter called roughening copper plating) in orderto improve the resin adhesion. The detail of the roughening copper plating is introduced below.

MAJOR
CHARACTERISTICS
2.2.MAJOR
CHARACTERISTICS
The measurement result of the arithmetic mean height(Sa) and the developed interfacial area ratio (Sdr) for theroughening copper plating (the roughening height of 1, 3,5 μm) and the conventional technology of the chemicaletching, the nickel roughening and without roughening
treatment are shown in table 1. Since the Sa and Sdr ofthe roughening copper plating material are larger than theconventional technology, the result shows that the roughening copper material has a large uneven shape and thesurface area is increased. The high resin adhesion of theroughening copper plating is achieved based on theshape comparison with the conventional roughening
treatment.
Figure 1 shows the surface shape and cross-sectional
shape of various roughening treatment materials after
plating layer with nickel (0.75 µm), palladium (0.02 µm)

Surface roughness of the surface roughening treatment materials (the base material: EFTEC-64T-C, thickness: 0.125 mm).
Item

Arithmetic mean height(Sa) /µm
Developed interfacial area ratio(Sdr) / –Evaluation
Condition
Laser microscope
Microscopeobservation,Magnification
50 times

Roughening copper plating(Roughening height: 5 µm)

Roughening copper plating
Height: 1 µm

Height: 3 µm

Height: 5 µm

Nickelroughening

Etching

Withoutroughening

0.53

1.02

1.38

0.30

0.37

0.27

3.4

5.6

7.7

2.4

2.3

1.1

Nickel roughening

Without rougheningEtching

10 µm

10 µm

10 µm

10 µm

5 µm

5 µm

5 µm

5 µm

Figure 1 The SEM images of surface and cross section of the surface roughening treatment materials.

Furukawa Electric Review, No. 52 202154〉〉 Electronics & Automotive Systems

Roughening Copper Plating With High Resin Adhesion

Copper surface
Ni/Pd/Au plating surface
After the test under high temperature and high humidity

35

Pudding cup test
Epoxy resin: φ2.6 mm

Shear strength / MPa

30252015105120

Au wireφ25 mm, 190℃, 0.4 N, 10 ms
Bonder: SWB-FA-CUB-10Capillary: 1570-17-437GM

100
Pull strength / mN

and gold (0.01 µm) assuming its use as the ground layerof the noble metal plating lead frame, represented by thepalladium pre-plating lead frame (Pd-PPF). Since theroughening copper plating has a large uneven shape andthe resin easily penetrates in the shape because of its
large gap, a large anchor effect is expected.
Figure 2 shows the result of the shear strength measurement after the environmental test of the resin molded
sample shown in table 2. The roughening copper plating
treatment obtained a high resin adhesion for not only thecopper surface but after the noble metal plating.
Furthermore, since the resin penetrates in the unevenshape, the air tightness is excellent and prevents waterfrom penetrating into the inner part under high temperature and humidity environment, and also it is possible toprevent the degradation of the inner element based on
keeping the excellent resin adhesion.

806040200Roughening copper plating

Figure 3 The pull strength on wire bonding.

CONCLUSION
3.3.CONCLUSION
The roughening copper plating developed by Furukawa
Electric has a high resin adhesion and an environmental
resistance. In the case of using the ground layer, it canimprove the resin adhesion without damaging the mountability.
Table 3 shows the specification of a possible copper
strip with roughening copper plating. Our roughening
copper plating makes it possible to offer a proposal for
improvement according to the customer request.
Table 30Roughening
copper plating

Nickelroughening

Etching

Withoutroughening

Figure 2 The shear strength before and after theenvironmental test.

Table 2The condition of the environmental test and shear test.
ItemCondition

Resin mold condition

Used resin:EME-G630L (Sumitomo Bakelite Co., Ltd.)
Resin mold: 130℃, 90 min.
Mold size: φ 2.6 mm

High temperature andhigh humidity test

Temperature: 85℃, Relativehumidity: 85%, 168 hours(JEDEC MSL LEVEL1)

Shear test

Extrusion rate: 100 µm/s

Figure 3 shows the pull strength on wire bonding of theroughening copper plating and of the one without roughening treatment. The pull strength of the roughening copper plating is the same as the material without roughening treatment and the roughening copper plating has agood wire bonding property.

Without roughening

Specification.
Item

Manufacturing range

Type of base material

Copper-based lead frame material

Plate thickness

0.08 〜 0.6 mm

Width20 〜 75 mm

For more information, please contact:
Electronics Sales Department,
Global Marketing Sales Division
Request format:
https://www.furukawa.co.jp/srm/form/index.php?id=encopper

REFERENCES
1) Fuji Keizai Management Co., Ltd., “2019 version of Next generationof the power device and power electronics related market for
current status and future outlook” (2019) pp.162-178. (in Japanese)
2) Yasuaki Suzuki, “Mechanism of Bonding of Dissimilar Materials
and Applied Technology” Journal of the Adhesion society of Japan
vol.54 (2018) pp.169-186. (in Japanese)
3) Akihiro Aiba, “Post Surface Treatment Agent and Technology for
IC Leadframe with High Performance and Reliability” Journal ofthe Surface Finishing Society of Japan vol 60 (2009) pp.243-247.
(in Japanese)

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