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A material and process development of a tn-level resist system is carried out to introduce the resist system into l3Onm and llOnm device fabrication. The tn-level resist system consists of organic films as a bottom layer, spin-onglass (SOG) as a middle layer and DUV photoresists as a top imaging layer. A wettability and an acidity of the SOG film are adjusted depending on the type of resist materials to obtain a desirable resist profile. The anti-reflective performance of the tn-level resist system is evaluated along with the lithographic performance. A light reflection (reflectivity) in the DUV photoresist film is reduced less than 0.5% for both KrF resist and ArF resist by choosing the nominal thickness of the SOG film and the bottom layer. A conventional DNQ-Novolak type MUV resist is used for the bottom layer in the KrF tn-level resist system. The MUV resist is thermally cured to avoid mixing with the SOG and to increase the optical density at 248nm wavelength. A newly developed spin-on-carbon film is used for the bottom layer in the ArF tn-level resist system. The spin-on-carbon has an excellent dry etch resistance because of its high carbon content (>90%). The dry etch rates of the MUV resist and the spin-on-carbon for CF4/O2IAr etch chemistry (SiN RIE condition) are 372nm/min and 287nm/min respectively. A pattern transfer using the tn-level resist system is demonstrated for both L/S and hole structures.

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