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The formation of a high adhesive noble metal layer on an oxide layer has been investigated in the Pt/(Ti)/TiO2/SiO2/Si system, prepared in a vacuum evaporation apparatus. The thermosonic ball bonding test and the conventional pull test were successively applied to the evaluation of adhesion. The Ti inserted layer between the Pt and the TiO2 layer was found to improve the adhesion. A Ti layer of approximately 10 nm was found to be necessary for stronger adhesion. Auger electron spectroscopy (AES) depth profile results showed that a part of the Ti atoms in the inserted layer were segregated to the Pt surface from the interface by annealing at 1373 K for 30 min, while the rest of Ti atoms in the inserted layer remained and acted as a ‘‘glue’’ at the interface between the Pt and the TiO2 layer. It should be noted that Ti could not be detected in the Pt layer within the AES detection limits. Scanning electron microscope and energy dispersive x-ray spectroscopy observations showed that Ti diffusion occurred through the grain boundaries of the Pt layer and Ti atoms appeared at surface grain boundaries on top of the Pt layer.

Etching on Sill 10) in KOH aqueous solutions containing a small amount of Cu has been studied.It is found that 100ppb-level Cu in KOH aqueous solution forms pyramidal shaped hillocks of Si and roughes the etched surface. It is understood that the hillocks are caused by masking effect of Cu particles deposited on Si. The results also show that 100ppb-level Cu reduces the etching rate since the hillocks consist of slowly etched {311} planes

Interface structures and adhesion to silicon after different surface pretreatments have been investigated for Ni(500–1000 nm)/Ti(250 nm) films prepared in a dc planar magnetron sputtering apparatus. In order to obtain high adhesion, a chemical pretreatment (with buffered HF) has been found to be favorable in comparison with a conventional Ar ion bombardment pretreatment (with cathodic voltage: 400 V). High resolution transmission electron microscopy (HRTEM) showed that there were two layers between Ti and Si in the case of Ar ion bombardment pretreatment. Energy dispersive x-ray spectroscopy (EDS) and electron diffraction (ED) showed that they were amorphous Ti–Si alloy and amorphous Si containing Ar. Moreover, a peeling pattern, after the test with adhesive tape, could be found at the boundary between the amorphous Ti–Si alloy layer and the amorphous Si layer containing Ar by using x-ray photoelectron spectroscopy (XPS). In the case of chemical pretreatment, only an amorphous Ti–Si alloy layer was observed between Ti and Si, and peeling was not observed. The differences in interface structure and adhesion are considered to be influenced by the Ar implanted during the Ar ion bombardment pretreatment.

Effects of different pretreatments on the surface structure of silicon and the adhesion of metal films Ni(100-1000 nm)ITi(250 nm) films were prepared by dc planar magnetron sputtering on Si (100) surfaces. Interface structures between Ti and Si and adhesion of the Ti films to Si after different surface pretreatments have been investigated. Before the film deposition, the Si substrate received an Ar ion bombardment or a chemical etching treatment. In the case of the Ar ion bombardment, we have investigated the effect of the cathodic voltage. A low cathodic voltage (50 V) resulted in high adhesion. The results by Rutherford backscattering spectroscopy showed that the amount of Ar incorporated in the Si surface during the Ar ion bombardment is increased with the cathodic voltage. The existence of Ar at the interface between the Si substrate and the Ti-Si mixed layer seems to lower the adhesion. In the case of the chemical pretreatment, we have investigated the effect of the exposure time in the atmosphere after the chemical etching treatment. A shorter exposure time (within 1 h) has been found to be preferred to a longer exposure time. The results of Auger electron spectroscopy and the peeling test showed that the exposure time is related to the oxide thickness, the Ti-Si aHoy thickness, and the adhesion. It is considered that the stable Si0 2 formation prevents the Ti-Si mixed layer formation and lowers the adhesion.