Study On Glass Frit Used In Thick-film Conductive Paste For AlN

In this paper, based on the study of preparation technology, composition and performance of the thick-film paste, how to achieve low temperature melting glass binder used in thick-film paste had been mainly studied. State-of-the-art techniques such as sol-gel method, screen printing and sintering were used for sample preparation. Effects of process and glass frit on the properties of thick-film conductor had been analyzed with XRD,TG-DSC and SEM.First, glass binder prepared by sol-gel method had been investigated. It was showed that a homogeneous, transparent and stable sol solution can be obtained when the composition was accorded with(wt%)CaO 40, B₂O₃ 15, SiO₂ 35, BaO 10 and partially hydrolyzing tetraethyl orthosilicate of 30 min before mixing with others rough material; effects of different H₂O/TEOS, and PH value on the performance of gel had been analyzed, it was found that gelling process is obvious and gelling time is shortest in conditions of H₂O/TEOS=10 and PH=5; effect of the source of barium and its soluble on the sol solution have been discussed, it was showed that gel with excellent performance can be obtained when use barium acetate as the source of barium; in condition, formulate reasonable heat treating regime is necessary. In order to effectively remove the pore and retained water, and to decompose the residual organic substance and nitrate, the dry-gel must be calcined after 700℃.Next, wetting characteristics between glass and substrate has been discussed. In order to achieve a good film adhesion, it is necessary to research the wetting behaviour(850℃) of CaO-B₂O₃-SiO₂-BaO system glass. It was proved that wetting angle is smaller 30°, the glass enrich on substrate and diffuse to its grain boundary.Last, the process of thick-film paste is primarily explored. Effect of viscosity, glass content, sintering temperature on the properties of film have been investigated. It was found that in order to achieve good conductor-substrate interface, it is necessary to ensure the sintering temperature at 850℃. In addition, it was proved that when the glass content is 10%, film adhesion achieve maximum(83N); the square resisitance would be higher when glass content is increasing, and this trend will accelerated when the glass content more than 15%.