FIELD INVERSION GENERATED IN THE CMOS DOUBLE-METAL PROCESS DUE TO PETEOS AND SOG INTERACTIONS

Abstract

Severe field inversion has been observed in the circuits fabricated by the CMOS double metal process using PETEOS/inorganic SOG/PEOX as the inter-metal dielectrics and PEOX/PECVD nitride as the passivation layer. We have performed detailed studies to conclude that the field inversion is caused by the interaction between PETEOS and non-carbon-based SOG, triggered by the H+ released from PECVD nitride during the sintering. No field inversion is observed when PEOX/inorganic SOG/PEOX is used as the inter-metal dielectrics. The effect of field inversion on the circuit yield is also discussed.