A new hybrid method for H2S-sensitive devices using WO3-based film and ACF interconnect

Abstract

A new hybrid integration method has been reported for process simplification of conventional metal-oxide sensors with a gold (Au) dopant-like catalyst during hydrogen sulfide (H2S) gas detections at room temperature. Different from conventional fabrications, an anisotropic conduction film (ACF) followed by a sputtered tungsten oxide (WO3) film tapped on Cu electrodes has been utilized in consumer applications. The process steps were reduced without compromising electrical performances. The treated ACF with a thin WO3 film, coated across two closely spaced microelectrodes is employed as the H2S solid-state sensor at room temperature. Apart from exhibiting good interconnects as conductive bumps, Au dopant-like catalyst within ACF will also produce a lower barrier between the bands of electronics, and therefore improve the electrical conductivity significantly. Our integration method offers a number of merits, including high sensitivity to the reference gas, lead-free bonding connection, low-temperature fabrication, high throughput and less fabrication time.