Field inversion generated in the CMOS double-metal process due to PETEOS and SOG interactions

Severe field inversion was observed in circuits fabricated by the CMOS double metal process using PETEOS/inorganic SOG/PEOX as the intermetal dielectrics and PEOX/PECVD nitride as the passivation layer. The authors performed detailed studies and concluded 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 was observed when PEOX/inorganic SOG/PEOX was used as the intermetal dielectrics. The effect of field inversion on the circuit yield is also discussed