Spin-on Organic Hardmask Materials in 70nm Devices

摘要

In ArF lithography for < 90nm L/S, amorphous carbon layer (ACL) deposition becomes inevitable process because thin ArF resist itself can not provide suitable etch selectivity to sub-layers. One of the problems of ACL hardmask is surface particles which are more problematic in mass production. Limited capacity, high cost-of-ownership, and low process efficiency also make ACL hardmask a dilemma which can not be ignored by device makers. One of the answers to these problems is using a spin-on organic hardmask material instead of ACL hardmask. Therefore, several processes including bi-layer resist process (BLR), tri-layer resist process (TLR), and multi-layer resist process (MLR) have been investigated. In this paper, we have described spin-on organic hardmask materials applicable to 70nm memory devices. Applications to tri-layer resist process (TLR) were investigated in terms of photo property, etch property and process compatibility. Based on the test results described in this paper, our spin-on hardmask materials are expected to be used in mass production.