| Summary: | 碩士 === 國立成功大學 === 化學工程學系碩博士班 === 95 === In recent years, many LTCC systems were made up of Al2O3 and glass. However, due to the low thermal conductivity of Al2O3, the LTCC systems of Al2O3 and glass have a poor thermal conductivity. AlN, whose thermal conductivity is 10 times greater than that of Al2O3, can be substituted for Al2O3 to improve the thermal conductivity of LTCC. LTCC process temperature is at 800~1000℃, but AlN will be oxidized in air above 700℃. The thesis includes two parts. The first part is focused on the thermal
oxidation of AlN powder；The second part is to find an optimal AlN/glass
LTCC process.
At part 1, the AlN powder employed in this thermal oxidation study has different particle size, and the main variables are different pressure, temperature, and addition of glass powder. At the results, because the smaller size of AlN has larger specific surface area, the oxidation is remarkably enhanced. Low pressure(2~3 torr) has low oxygen content, and makes AlN oxidation reduce 10~15 times than atmosphere, addition of glass powder in melt point can cover with AlN surface and form a protective layer to retard oxidation. Therefore, addition of glass powder and low pressure can retard
oxidation behavior of AlN.
The second part was a new type of LTCC AlN/glass to study the effects of AlN particle size, AlN/glass weight ratio, sintering temperature, pressure, and holding time etc. According to the result of AlN/glass composites density, thermal properties, electronic and mechanical properties, we can find optimal AlN/glass LTCC process. In the study, the highest thermal conductivity is 10.874 W/mK and close to the present research. Comparison with commercial LTCC materials is greater than 1.7 times. Therefore, addition of AlN powder
can rise up thermal conductivity.
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