Stability Of Plating Bath Research Articles

Electroless nickel underlayer deposited between copper filler and silicon substrate: effect of bath pH

ABSTRACT This research proposed intermediate materials between Cu filler and Si wafer to reduce the coefficient of thermal expansion (CTE) mismatch in the through silicon via (TSV) structure. The proposed material is Ni underlayer because it has CTE value between Cu and SiO2 which is 13 ppm/°C (Cu = 17 ppm/°C, SiO2 = 0.6 ppm/°C). The deposition process of nickel underlayer was conducted using electroless deposition process at various pH value (4.5, 5.5 and 6.5) of plating bath and deposition time (20, 40 and 60 minutes). The deposition behaviour was studied through surface and cross-sectional analysis under scanning electron microscopy (SEM). The Ni thickness was measured using cross-sectional analysis under SEM. The chemical composition of Ni deposits was measured using energy dispersive spectroscopy equipped on SEM. The performance test analysis was conducted using Standard ASTM D3359 (Cross Hatch Tape-Test) for coating adhesion test and 4-Point Probe Test for resistivity measurement. It was found that the optimum pH of the Ni bath is 6.5 due to high stability of plating bath to form uniform Ni deposited on silicon wafer. These optimum coating parameters showed homogeneous and uniform distribution of Nickel deposited on the surface of silicon with excellent adhesion properties for all pH value.

Influence of temperature and pH value on deposition rate and corrosion resistance of Ni–Zn–P alloy coating

The Ni–Zn–P alloy coating has excellent physical and chemical properties that have been exploited for various industrial applications. Using sodium citrate as a complexing agent and lactic acid as a stabilizer, the effects of temperature and pH on the deposition rate and corrosion resistance of electroless plated Ni–Zn–P coating were studied. The results indicated that, when the temperature was 85[Formula: see text]C, a good deposition rate was obtained with stable plating solution. pH value of 9.0 is preferred for the coating process by considering the stability of plating bath and deposition rate. The Ni–Zn–P alloy coating deposited with plating temperature of 85[Formula: see text]C and bath pH of 9.0 has good quality, and a uniform and smooth surface texture without porosity.

Preparation and magnetic properties of Ni–P–La coating by electroless plating on silicon substrate

Ni–P–La coatings were prepared on Si substrate by electroless plating method under different La content, pH value, plating temperature and plating time. The surface morphology, chemical composition, structure and magnetic properties of coatings were observed and determined by scanning electron microscope (SEM), energy dispersive X-ray spectrometry (EDS), X-ray diffractometer (XRD) and vibrating sample magnetometer (VSM). The results showed that Ni–P–La coating is smooth and uniform with a cellular morphology grown in columnar manner. With the increase of La content, pH value and plating time, the thickness and saturation magnetization of coating are increased continuously, but the stability of plating bath is decreased greatly with La content and pH value. Under higher plating temperature, the thickness and saturation magnetization of coatings are obviously enhanced. But too high plating temperature is harmful to the plating bath and coating. The optimum plating conditions for Ni–P–La coating is La2O3 addition of 10mgL−1, pH value of 5.0, plating temperature of 75°C and plating time of 45min. The role of La element is to benefit the deposition of Ni element, promote the formation of Ni phase during the annealing process, and thus improve the magnetic properties of Ni–P–La coating.

ＤＩＢＡＨとＢｉＣｌ３を含むＡｌＣｌ３‐ＥＭＩＣ室温イオン液体を用いた無電解Ａｌめっき

We investigated electroless aluminum plating using AlCl3-1-ethyl-3-methylimidazolium chloride (AlCl3-EMIC) ionic liquid containing diisobutyl aluminum hydride (DIBAH) and BiCl3. The plating film was analyzed using X-ray diffraction and scanning electron microscopy. The aluminum films prepared with BiCl3 were smoother than those prepared without BiCl3. Furthermore, the plating bath stability was improved by addition of BiCl3.