Comparative study of electrically conductive thick films with and without glass

Abstract

An air-fireable, glass-free, electrically conductive thick-film material (96.6% Ag, 1.38% Cu, 0.28% Al, 0.35% Ti, and 1.39% Sn by weight) and a conventional glass-containing, electrically conductive thick-film material (96.6% Ag and 3.4% glass frit by weight), both on alumina substrates, were studied by electrical, mechanical, thermal, and microscopic methods. The volume electrical resistivity of the glass-free thick film (2.5 ϫ 10 Ϫ6 Ω·cm, 30-µm thick) is lower than that of the glass-containing thick film (3.9 ϫ 10 Ϫ6 Ω·cm, 19-µm thick), with each film processed at its optimum firing temperature. The optimum firing temperature is 930°C and 850°C for glass-free and glass-containing thick films, respectively, as indicated by the criteria of low resistivity and high scratch resistance. The glass-free thick film has a higher scratch resistance than the glass-containing thick film, both fired at their respective optimum temperatures, suggesting that the former has higher bond strength to the alumina substrate. The formation process of the glass-free and glass-containing thick films is similar. The process involves solid-state diffusion of silver, which results in a silver network and grain boundaries. However, the sintering of silver particulates in the glass-containing thick film is enhanced by the viscous flow of glass.

Burnout of the organic vehicle in an electrically conductive thick-film paste

“…2a of Ref. 37, which shows only one exothermic peak corresponding to the higher temperature peak in Fig. 3d for the case in which DSC testing of the thick-film paste is conducted after drying the thick film in air for two days.…”

Effect of firing atmosphere on air-fireable glass-free electrically conductive thick film

“…22 Good coverage of the substrate by the film means less pinholes in the film, i.e., a denser film. Firing in oxygen instead of air causes more metal oxide and consequently better bonding.…”

Characteristics of silver–glass composite powders as the silver electrode for Si solar cells

“…A micron-sized glass frit with irregular morphology prepared by a conventional melting process is mainly used as a sintering agent in silver paste [4][5][6][7]. The characteristics of silver conducting films are affected by the composition of glass frits [8][9][10]. Glass frit with a softening point of 450-550 • C is generally used as the inorganic binder.…”