Sains Malaysiana 52(11)(2023): 3261-3271

http://doi.org/10.17576/jsm-2023-5211-18

Effect of Sn Plating Thickness on Wettability, Solderability, and Electrical Connections of Electronic Lead Connectors for Surface Mount Technology Applications

(Kesan Ketebalan Saduran Sn terhadap Kebolehbasahan, Kebolehpaterian dan Sambungan Elektrik bagi Kaki Penyambung Elektronik untuk Aplikasi Teknologi Lekapan Permukaan)

MARIA ABU BAKAR^1,*, MOHAMAD SOLEHIN MOHAMED SUNAR^1,2, AZMAN JALAR^1,3, A ATIQAH¹, FAKHROZI CHE ANI², IBRAHYM AHMAD² & ZOL EFFENDI ZOLKEFLI²

¹Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

²Western Digital®, SanDisk Storage Malaysia Sdn. Bhd. Plot 301A, Persiaran Cassia Selatan 1, Taman Perindustrian Batu Kawan, MK13, Batu Kawan, Seberang Perai Selatan, 14100, Penang, Malaysia
³Department of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

Received: 1 August 2023/Accepted: 19 October 2023

Abstract

The wettability of solder is important to achieve good solderability between the electronic component and printed circuit board (PCB). Tin (Sn) plating is widely used to promote the wettability of the solder on the substrates. However, an adequate amount of Sn plating thickness must be taken into consideration to acquire good wettability and solderability. Thus, this study investigates the Sn plating thickness of the electronic lead connector and their effect on the wettability and electrical connection. Two types of Sn plating thicknesses, ~3 μm, and 5 μm were applied on the electronic lead connector surface. It was found that the thin Sn plating thickness of ~3 μm has shown failure in electrical connections and lack of solder joint wettability and solderability properties. A thicker Sn plating thickness of 5 μm, has shown better wettability and solderability properties. In addition, the electrical connections also passed which implies that the thicker Sn plating thickness provides good solder joint establishment leading to good electrical connections. It is also observed that the better wettability of solder has been achieved for thicker Sn plating thickness. The finding from the field emission scanning electron microscope (FESEM) shows that the intermetallic compound (IMC) layer growth in the lead connector surface is regarded as abnormal for thin Sn plating thickness (~3 μm), in which the IMC layer was consumed and penetrating up to the surface of Sn-coating.  This has led to poor solderability of the thin Sn plating with the solder to establish solder joint. The findings from this study have shed some light upon a better understanding of the importance of considering the adequate amount of Sn coating thickness to avoid IMC consumption at the Sn plating, better wettability properties, solderability, and solder joint quality for surface mount technology (SMT) especially for electronic lead connector applications.

Keywords: Electronic lead connector; IMC consumed at Sn plating; Sn plating thickness; solderability; surface mount technology; wettability

Abstrak

Kebolehbasahan pateri adalah penting untuk mencapai kebolehpaterian yang baik antara komponen elektronik dan papan litar bercetak (PCB). Saduran timah (Sn) digunakan secara meluas untuk menggalakkan kebolehbasahan pateri pada substrat. Walau bagaimanapun, ketebalan saduran Sn yang mencukupi harus diambil kira untuk memperoleh kebolehbasahan dan kebolehpaterian yang baik. Oleh itu, penyelidikan ini mengkaji ketebalan saduran Sn pada kaki penyambung elektronik dan kesannya terhadap kebolehbasahan dan sambungan elektrik. Dua jenis ketebalan saduran Sn, ~3 μm, dan 5 μm diaplikasikan pada permukaan kaki penyambung elektronik. Didapati bahawa saduran Sn yang nipis, ~3 μm telah menunjukkan kegagalan sambungan elektrik dan kekurangan dari segi sifat kebolehbasahan dan kebolehpaterian sambungan pateri. Saduran Sn yang tebal, 5 μm menunjukkan sifat kebolehbasahan dan kebolehpaterian yang lebih baik. Di samping itu, sambungan elektrik yang lulus menunjukkan bahawa ketebalan saduran Sn yang tebal menghasilkan sambungan pateri yang baik seterusnya memberikan sambungan elektrik yang baik. Turut diperhatikan bahawa kebolehbasahan pateri yang baik dicapai untuk saduran Sn yang tebal. Keputusan mikroskop elektron imbasan medan pancaran (FESEM) juga menunjukkan bahawa pertumbuhan lapisan sebatian antara logam (IMC) pada permukaan kaki penyambung dengan saduran Sn nipis (~3 μm) adalah tidak normal, yang mana lapisan IMC telah memakan dan menembusi ke permukaan saduran Sn. Ini mengakibatkan kebolehpaterian yang lemah antara pateri dan saduran Sn nipis untuk menghasilkan sambungan pateri. Penemuan daripada kajian ini telah memberikan pencerahan dan pemahaman yang lebih baik tentang kepentingan untuk mengambil kira ketebalan saduran Sn yang mencukupi bagi mengelakkan IMC memakan saduran Sn, sifat kebolehbasahan, kebolehpaterian dan kualiti sambungan pateri yang baik bagi teknologi lekapan permukaan (SMT) khususnya bagi aplikasi kaki penyambung elektronik.

Kata kunci: IMC memakan saduran Sn; kaki penyambung elektronik; kebolehbasahan; kebolehpaterian; ketebalan saduran Sn; teknologi lekapan permukaan

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*Corresponding author; email: maria@ukm.edu.my