Intermediate SiO2 Layer Research Articles

Multilayered Structures and Magnetic Properties of Fe¿Si¿Ru Multilayered Films

A method for controlling the domain structure by improving the multilayerization of Fe-Si-Ru alloy, Ni-Fe alloy and SiO2 to improve the reproduction sensitivity of single-pole perpendicular magnetic heads. Measurements of the permeability of the Fe-Si-Ru multilayered film before and after patterning revealed that before patterning it was almost constant at 2200 up to an intermediate SiO2 layer thickness of 30 nm, and that it decreased above that point, but after patterning, the permeability improved as the SiO2 layer thickness increased and reached a maximum of 1000 at 20 nm.

アモルファスＣｏ９１Ｈｆ６Ｐｄ３／ＳｉＯ２／Ｃｏ９１Ｈｆ６Ｐｄ３積層膜の磁気特性と磁区構造

The magnetic domain structure and the magnetization process of amorphous Co91Hf6Pd3/SiO2/amorphous Co91Hf6Pd3 multi-layered films which were photofabricated in rectangular patterns have been investigated.Exchange interaction between magnetic layers 1500 Å thick occurs when the thickness of the intermediate SiO2 layer prepared by sputtering is less than about 10 Å. When the SiO2 layer is about 10000 Å thick, however, magnetostatic interaction becomes weak and the magnetic layers become independent of each other. We have determined that when multilayered films have an SiO2 layer from 20 to 600 Å thick and are at least 10μm wide along the easy axis, no domain walls are present because magnetostatic interaction causes the magnetization of one magnetic layer to be oriented anti-parallel to that of the other along the easy axis.When a magnetic field is applied along the easy axis, the domain walls nucleate and displace only in the magnetic layer whose magnetization is anti-parallel to the field. On the other hand, when multi-layered films are subjected to a magnetic field along the hard axis, their magnetization is rotated.

High resolution trilevel resist

A detailed study of film formation and directional etching for high-resolution trilevel resist was performed. The top layer was CMS and AZ-1350. The intermediate layer was ion beam sputter- deposited SiO2. The bottom layer was AZ-1370. High-temperature baking of the bottom layer prevents crack generation in the SiO2 intermediate layer. Reactive ion etching in O2 gas plamsa with a carbon electrode was used to pattern the bottom layer and gave a residue-free etched surface. A study was made of undercutting during O2 etching with power, temperature, and pressure varied over wide ranges. The results agree with spectroscopic observations of the variation in the ratio of excited neutral species to ionic species in the plasma. Low pressure and low substrate temperature during the bottom layer etching were found to be necessary for a low undercut. The viability of the trilevel resist for submicron patterning was verified.

High resolution, steep profile resist patterns

High resolution and steep profile patterns have been generated in a 2.6 μm thick organic layer which conforms to the steps on a wafer surface and is planar on its top. This thick organic layer (a photoresist in the present experiments) is covered with an intermediate layer of SiO2 and a top, thin layer of x-ray or photoresist. After exposure and development of the top resist layer, the intermediate layer is etched by CHF3 reactive ion etching. The thick organic layer is then etched by O2 reactive ion etching. Submicron resolution with essentially vertical walls in the thick organic material was achieved. The technique is also applicable to photo and electron lithography. It reduces the need for thick resist patterns for the lithography step and, at the same time, ensures high resolution combined with good step coverage.