An Improved Thick Film Aluminium Conductor Process

[摘要] Aluminium thick film conductors offer very large cost advantages compared with noble metals and can also improvethe reliability of circuits by eliminating gold-aluminium interfaces and their attendant intermetallic phenomena. Todate however, it has not been possible to produce aluminium thick film conductors which are ultrasonicallybondable to aluminium-silicon wire.This paper describes a study of the microstructure and line profile of a commercially available aluminium thickfilm paste as a function of firing schedule. Scanning electron microscopy has revealed the mechanisms which controlthe sintering process and has suggested a revised firing schedule. It is shown that firing schedules exist which yieldconductors with adequate ultrasonic bondability and conductivity. The results of bond ageing experiments on bondstrength and conductivity are given for periods of up to 1200 h at temperatures of 60–200℃.It is shown that bonds of aluminium wire to aluminium thick film are resistant to loss of bond strength but sufferfrom loss of conductivity on ageing at 150℃.

[学科分类] 工程和技术（综合）