AVS 45th International Symposium
    Thin Films Division Monday Sessions
       Session TF-MoP

Paper TF-MoP25
Density Measurement of Thin Glass Layers for Gas Barrier Films

Monday, November 2, 1998, 5:30 pm, Room Hall A

Session: Thin Films Poster Session
Presenter: N. Fukugami, Toppan Printing Co., Ltd., Japan
Authors: N. Fukugami, Toppan Printing Co., Ltd., Japan
H. Nishino, Toppan Printing Co., Ltd., Japan
M. Yanaka, Toppan Printing Co., Ltd., Japan
Y. Tsukahara, Toppan Printing Co., Ltd., Japan
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In the food packaging industry, there is an increasing demand for transparent gas barrier films consisting of a 10 ~ 100 nm thick glass layer deposited on a polymer substrate. An advantage of such films is that microwaves and light waves can penetrate. It was confirmed that our glass layer had no macro defects or pinholes, and the gas penetration mechanism was mainly due to a nano structure of the glass layer.@footnote 1@ It is anticipated that the density of the glass layer is an important factor to characterize such nanostructures. Therefore, an accurate density measurement of thin layers with thicknesses ranging from 10 nm to 100 nm was needed. We used a weight-volumetric method, and obtained the density with three digits accuracy. First, densities of SiOx layers which were deposited by vacuum evaporation on Si (100) surfaces were measured. The Si surfaces were used because they were well-characterized and smooth. The volume of a layer was obtained as a product of the layer thickness and its area. The area was defined by a window which was located in front of the Si substrate during the deposition. The thickness was obtained by measuring the edge height of stripes made over the entire surface by photolithography process. Dektak (Dektak3030, Nihon Shinku Gijutsu Inc.) was used for the edge height measurement. A weight of the layer was measured by Ultramicrobalance (Sartorius supermicro, Sartorius Inc.). The densities thus obtained were 2.15±0.01g/cm@super 3@ and 2.16± 0.03g/cm@super 3@ for layers with slightly different deposition conditions. Next, a novel method was invented for the density measurement of thin glass layers deposited on polymer substrates. The method made use of the fact that parallel multiple cracks were induced in the glass layer when the film was stretched.@footnote 2@ The thickness of the glass was obtained by measuring the depths of crack openings. The accuracy of the measurement was also investigated. @FootnoteText@ @footnote 1@B. Henry, et. al., presented at the 41st Society of Vacuum Coaters Technical Conference (April 1998). @footnote 2@M. Yanaka, Y. Tsukahara, N. Nakaso and N.Takeda, accepted to the J.Mat.Sci., 1998.