Plasma charging damage and water-related hot-carrier reliability in the deposition of plasma-enhanced tetraethylorthosilicate oxide

This paper presents plasma-enhanced tetraethylorthosilicate oxide process (PETEOS) induced hot-carrier reliability associated with an intermetallic dielectric formed by depositing oxide films from PETEOS, ozone-TEOS, and spin-on glass (SOG), where a single or dual-frequency PETEOS film is deposited as an underlayer followed by an ozone-TEOS deposition for gap filling and a SOG coating for planarization. The impact of PETEOS process conditions such as low-and high-frequency plasma power and PETEOS film thickness on hot-carrier reliability are studied. It is observed that increasing the low- and/or high-frequency plasma power can improve the film quality and moisture-related hot carrier immunity, but at the expense of plasma charging damage. This plasma charging damage accumulates gradually and finally saturates as the deposition of oxide from PETEOS proceeds. In general, a thick PETEOS layer is desired for improving the moisture-related hot carrier immunity. As a result, there is a trade-off between the plasma charging damage and the moisture-related hot carrier immunity. The plasma charging damage is dominant in large devices and the moisture-related hot-carrier immunity is dominant in small devices.