• Journal of the Korean Vacuum Society
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• v.7 no.4
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• pp.368-373
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• 1998

As device dimensions approach submicrometer size in ULSI, the demand for interlayer dielectric materials with very low dielectric constant is increased to solve problems of RC delay caused by increase in parasitic resistance and capacitance in multilevel interconnectins. Fluorinated amorphous carbon in one of the promising materials in ULSI for the interlayer dielectric films with low dielectric constant. However, poor thermal stability and adhesion with Si substrates have inhibited its use. Recently, amorphous hydrogenated carbon (a-C:H) film as a buffer layer between the Si substrate and a-C:F has been introduced because it improves the adhesion with Si substrate. In this study, therfore, a-C:F/a-C:H films were deposited on p-type Si(100) by ECRCVD from $C_2F_6, CH_4$and $H_2$gas source and investigated the effect of forward power and composition on the thickness, chemical bonding state, dielectric constant, surface morphology and roughness of a-C:F films as an interlayer dielectric for ULSI. SEM, FT-IR, XPS, C-V meter and AFM were used for determination of each properties. The dielectric constant in the a-C:F/a-C:H films were found to decrease with increasing fluorine content. However, the dielectric constant increased after furnace annealing in $N_2$atomosphere at $400^{\circ}C$ for 1hour due to decreasing of flurorine content. However, the dielectric constant increased after furnace annealing in $N_2$atmosphere at $400^{\circ}C$ for 1hour due to decreasing of fluorine concentration.

• Journal of Nutrition and Health
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• v.3 no.3
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• pp.129-135
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• 1970

From the previous studies, F-P-4 formula was found to be comparable to full fat dry milk in its nutritive value and feeding performance. However, an attempt was made in order to make sure whether or not any possibility might exist, by which further improvement of nutritive quality and simultaneous reduction of product costs may be achieved. Using F-P-4 as a control, modifications were made in new formulas, F-P-5, F-P-6 and F-P-7 by reducing FPC, eliminating yeast from the mixture, and by enriching with methionine as needed. In particular, F-P-7 is completely free of FPC, hydrogenated oil and yeast. Yet, levels of total protein and fat were kept equal to those of F-P-4 in all formulas. An animal feeding test for all formulas using 10 female rats per group for 8 weeks and an infant feeding trial for F-P-5 and F-P-6 with 5 of each female infants under age of one for one month were conducted along with F-P-4 as a control. Almost the same results were obtained with F-P-4, 5 and 6, but F-P-7 showed the lowest body weight gain. FER of F-P-5 and 6 was 0.20 as was with F-P-4, while that of F-P-7 was 0.16. Acceptability to infants was excellent; growth, appearance and biochemical data were normal. As an example F-P-4 packed in 0.04mm polyethylene bags was used for storage study at $25^{\circ}C$ and relative humidity of $65{\sim}85%$ for 8 months. Although viable bacterial counts and vitamin C contents were reduced, peroxide and TBA values were increased gradually during such storage. Since there are also significant changes in color and organoleptic quality, the expected shelf life under the given conditions is considered to be about 2 months and thus further works are needed both on the product and packaging in order to improve the storage stability. Either elimination of yeast form F-P-4, that is F-P-5, or partial replacement of FPC with methionine, that is F-P-6 may well reduce material costs about 10%. Considering blending process of ingredients, F-P-5 is thus found to be the best formula developed. While F-P-7 free of FPC is inferior in its nutritive quality than that of others, but significantly superior than of rice. Furthermore, the material cost of the product can be reduced about 20% from that of F-P-4. And thus this vegetable blend is considered to be useful as a low cost supplementary food mixture for growing children.