Selective Sidewall Airgap Integration for Deep Submicrometer Interconnects

A novel process for narrow, ca. 100 nm wide, airgap formation based on chemical selectivity is presented. First, chemically modified sites are induced at the Ta(N)/SiC interface during patterning operations. Then, the SiO2 material lying between copper lines is locally removed by vapor HF exposure, leading to air cavity formation between closely packed interconnects. Based on simulations this sidewall airgap concept has a promising potential for very narrow interline dielectrics in future interconnect generations. (C) 2004 The Electrochemical Society.