Cu-filled through-hole electrode for ZnS using high adhesive strength Ni–P thin film

• Published in: Electrochimica acta Vol. 82; pp. 363 - 366
• Main Authors: Okamoto, Naoki, Miyamoto, Megumi, Saito, Takeyasu, Kondo, Kazuo, Fukumoto, Takafumi, Hirota, Masaki
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Kidlington Elsevier Ltd 01.11.2012; Elsevier
• Subjects: Chemistry; Electrochemistry; Electrodeposition; Electroless deposition; Exact sciences and technology; General and physical chemistry; Ni–P; Study of interfaces; ZnS; Ni–P; Cu; ZnS; Electroless deposition; Electrodes; Hole; Adhesive strength; Zinc Sulfides; Ni-P; Electrochemical reaction; Electroless plating; Thin film
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2012.04.151

Zinc sulfide (ZnS) and related materials are important for applications in ultraviolet light emitting diodes, cathode ray tubes, flat panel displays and infrared ray (IR) windows. In order to utilize these optoelectronics devices in electronic products, 3D-packaging as well as wafer level packaging (WLP) are needed. The two methods used to achieve this are physical vapor deposition (PVD) and conventional electroless deposition processes. However, both these methods have problems. Films made by PVD are not always of uniform thickness if the substrate is not flat. On the other hand, films made by conventional electroless deposition have weak adhesive strength to substrates. In order to overcome these limitations, we developed a new electroless deposition process to form nickel–phosphorus (Ni–P) films. This process combines catalyzation (Cu deposition) and electroless deposition processes. The films made using the new process show high adhesive strength in tensile tests and also very uniform thickness. In addition, conformal Cu filling of through-holes was achieved by using this new electroless deposition process.