Articles you may be interested inInfinitely high etch selectivity during CH 2 F 2 / H 2 dual-frequency capacitively coupled plasma etching of silicon nitride to chemical vapor-deposited a -C

ArF lithography has been successfully implemented for the development of sub-lOOnm DRAM devices. Such issues as CD (critical dimension) slimming during in-line SEM inspection and low dry etch resistance especially for SiN etch conditions, however, are still latent showstoppers for the production with ArF process. To overcome these problems, there are many efforts for continuous improvements in terms of material and process together with intensive study of new inspection tool and dry etch system,.The curing process is one of promising candidates to stabilize the weak ArF resists. Many kinds of curing processes including e-beam curing, thermal curing, plasma curing, UV curing, and VUV (172nm) curing have been studied, and some of them have shown good effects until now. The new curing process with VUV (172nm) showed the most promising results. SEM induced CD slimming of ArF resist improved with 10 sec curing and D/E resistance highly increased with the curing. And there was no particle increase unlike e-beam curing process. And we also found that the re-flow of ArF resist with high Tg above degrathtion temperature was possible with the VUV curing. In this paper, the mechanism and properties ofVUV curing processes will be discussed.

The double-patterning process was investigated for line-and-space (L/S) patterns of 65 nm half pitch [k 1 ¼ 0:286, 0.85numerical aperture (NA) ArF dry system] by plasma treatment of photoresist (PR). The sequence of this patterning is exposure-plasma treatment-exposure-etching. Si thin-film passivation and HBr plasma treatment (HPT) were applied, and Si thin-film passivation is preferred to HPT in terms of intermixing prevention and etch selectivity. For planarization of the topographic surface, a thick bottom PR was coated on the pattern after the first exposure. Si thin-film passivation and the thick bottom PR enabled the second exposure to be separated from the first exposure. After the etching process was completed down to the nitride hardmask material, the L/S patterns of 65 nm half pitch were achieved at the full-chip level by virtue of the Si thin-film passivation and thick bottom PR. In the meantime, considering the layout characteristic and process flexibility, layout decomposition and the optical proximity correction (OPC) process were performed. Even though the 65 nm half pitch is defined to be such that k 1 ¼ 0:286, it is believed that this double patterning scheme we suggested can be applied at the minimum pitch over the theoretical limit below 0.25. Consequently, it is expected that the double-patterning technique (DPT) process will have an important role in the extremely low k 1 lithography beyond the 32 nm node.

It is expected that ArF lithography will be introduced for device manufacturing for sub-100 nm nodes, as high NA ArF step and scan systems (NA=O.75) become available. We previously reported on a platform, based on a vinyl ether-maleic anhydride (VEMA) alternating polymer system. This platform demonstrated both good resolution and high dry etch resistance in comparison to other platforms based on acrylate and cyclic-olefin-maleic anhydride (COMA) polymer systems. The VEMA platform has been continuously improved to meet the increasing requirements, such as resolution, depth of focus (DOF), iso-dense bias, and post-etch roughness for real device manufacturing. This VEMA system is being implemented for sub-100 nm device with high NA (NAO.75) =ArF exposure systems. In this paper, recent experimental results are reviewed. Photoresist, chemically amplified resist, ArF, lithography, VEMA.

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