Jun-Mi Jeon

A Study on the ENIG Surface Finish Process and Its Properties

Ni coating layers were formed using a newly developed electroless Ni plating solution. The properties of Ni coating layer such as internal stress, hardness, surface roughness, crystallinity, solderability and surface morphology were investigated using various tools. Results revealed that internal stress decreased with plating time and reached at 20 minutes of the plating time. Hardness increased with increasing P content and thickness. Surface roughness of the pad decreased with Ni and Ni/Au plating. Crystallinity decreased with increasing P content. Solderability based on wettability decreased with Ni and Ni/Au plating. Based on surface morphology, it is expected that Ni coating layer formed using a newly developed electroless Ni plating solution is lower than that formed using a commercial electroless Ni plating solution in possibility of black pad occurrence.

Microstructure and Properties of Ni-SiC Composite Coating Layers Formed using Nano-sized SiC Particles

Ni-SiC composite coating layers were formed using two kinds of SiC nano-particles by DC electrodeposition in a nickel sulfamate bath containing SiC particles. The effect of stirring rate and SiC particle type on the microstructure and properties of Ni-SiC composite coating layers were investigated. Results revealed that the trend of deposition rate is closely related to the codeposition of SiC and the deposition rate. or nickel, and the codeposition behavior of SiC can be explained by using hydrodynamic effect due to stirring. The average roughness and friction coefficient are closely related to the codeposition of SiC and SiC particle size. It was found that the Victors microhardness of the composite coating layers increased with increasing codeposition of SiC. The composite coating layers containing smaller SiC particle showed higher hardness. This can be explained by using the strengthening mechanism resulting from dispersion hardening. Anti-wear property of the composite coating layers formed using 130 nm-sized SiC nano-particles has been improved by 2,300% compared with pure electroplated-nickel layer.

Effect of Complexing Agents on Adhesion Strength between Electroless Copper Film and Ta Diffusion Barrier

Surface Technology R B revised August 6, 2014 ; accepted August 7, 2014)AbstractThe primary purpose of this research is to investigate how much the complexing agent in electroless Cuelectrolytes will affect adhesion strength between copper film and Ta diffusion barrier for Cu interconnectof semiconductor. The adhesion strength using rochelle’s salt as complexing agent was higher than the caseof using EDTA-4Na. Effect of complexing agent on adhesion strength and electrical resistivity was studiedin crystal structural point of view.

Effects of Co content on the Cu diffusion barrier property of electroless NiCoP film

The characteristics of electroless NiCoP films were investigated as a function of Co content. Sheet resistance of a multi-stacked film of SiO2/Ta/Cu/NiP dramatically increased after annealing at 500 °C, but as more Co was co-plated in NiCoP film, the change in sheet resistance of the stacked film of SiO2/Ta/Cu/NiCoP at 500 °C became smaller. A CoP/Cu film showed no change in resistance value after annealing, which indicates the CoP film is the most effective Cu diffusion barrier. X-ray diffraction analysis showed that an as-plated NiP film of amorphous structure is easily crystallized by thermal annealing over 300 °C, while CoP showed an insignificant change in crystal structure by thermal annealing up to 500 °C. This result reveals that the CoP film is capable of preventing the diffusion of Cu at 500 °C due to the thermal stability of CoP film.

Effects of Multi-Complex Agent Addition on Characteristics of Electroless Ni-P Solution

In this study, the effects of multi-complex agents addition on characteristics of electroless Ni plating solution are investigated. The species and the concentration of complexing agents are major factors to control the deposition rate, P concentration, and surface morphology of plating films. Adipic acid increases the deposition rate in regardless of single- or mutli-complex agent addition. However, lactic acid effectively increases the deposition rate in case of multi-addition as the complex agents with adipic or sodium succinate acid. In addition, sodium citric acid and malic acid show good stabilizing effects of plating solution and lowering the deposition rate, because they have high complexibility. Therefore, it is suggested that the development of Ni-P plating solution suitable for diverse usages can be carried out systematically using the database from this study.

Properties of Ni-P-SiC Composite Coating Layers Prepared by Electroless Plating Method

Ni-SiC composite coating layers were prepared by electroplating method and their deposition rate, codeposition of SiC, morphology, surface roughness, hardness, wear and friction properties were investigated. It was found that the deposition rate and the codeposition of SiC in the composite coating layer increased with increasing concentration of SiC in the solution only at the early stage. Both of them reached certain maxima and then decreased with increasing concentration of SiC. Rough surface was obtained with increasing codeposition of SiC, which is probably due to the agglomeration of the SiC particle in the vicinity of surface. Vickers hardness increased with increasing codeposition of SiC and heat treatment at in air for 1 hour. Wear volume decreased with increasing codeposition of SiC and friction coefficient increased with increasing codeposition of SiC at the early stage, and it became almost constant. Such wear and friction behaviors are desirable for the practical application.