Organic Bottom Anti-Reflective Coatings (BARCs) has been used in the lithography process. BARCs may play an important
role to control reflections and improve swing ratios, CD variations, reflective notching, and standing waves.
In 32-45nm node, application of the immersion lithography technique is not avoided to obtain the high resolution. To obtain
the high resolution, numerical aperture (NA) of the optical system needs the Hyper-NA lens of 1.0 or more but come up to the
problem of affections the polarized light in the Hyper-NA lens. The substrate of reflection control also will become more
difficult by using single BARCs system and the thin film resist becomes the necessity and indispensable at Hyper-NA
lithography. To achieve an appropriate reflection control, to suppress the CD difference to the minimum, and to prevent the
pattern collapse, hard mask with the spin coating film and antireflection characteristic is needed. In order to solve these issues,
we designed and developed new materials with the suitable optical parameter, square resist shape and large dry etching
selectivity. These Multi-layer materials of each process are spin-coated by using the current system and conventional ArF
photo resist or immersion resist is available in this process. This paper presents the detail of our newest materials for Hyper NA
The CD requirements for the 45nm-node will become tighter so as it will be difficult to achieve with 65nm node
technologies. In this paper, a method to improve resolution by using DRECE (Dry-etching Resistance Enhancement
bottom-Coating for Eb) will be described. After all, DRECE has five times as high dry-etch resistance than the EB resist,
and this enables to accept higher anisotropic dry etching condition. By optimizing dry etching conditions, the CD
iso-dense bias dropped to 1/3 and the CD shift was reduced to 1/2. Also, there was no negative effect to CD uniformity.
From these results, we propose the use of DRECE for the 45nm-node technology.
Integrated circuit manufacturers are consistently seeking to minimize device feature dimensions in order to reduce chip size and increase integration level. Feature sizes on chips are achieved sub 65nm with the advanced 193nm microlithography process. R&D activities of 45nm process have been started so far, and 193nm lithography is used for this technology. The key parameters for this lithography process are NA of exposure tool, resolution capability of resist, and reflectivity control with bottom anti-reflective coating (BARC). In the point of etching process, single-layer resist process can't be applied because resist thickness is too thin for getting suitable aspect ratio. Therefore, it is necessary to design novel BARC system and develop hard mask materials having high etching selectivity. This system and these materials can be used for 45nm generation lithography. Nissan Chemical Industries, Ltd. and Brewer Science, Inc. have been designed and developed the advanced BARCs for the above propose. In order to satisfy our target, we have developed novel BARC and hard mask materials. We investigated the multi-layer resist process stacked 4 layers (resist / thin BARC / silicon-contained BARC (Si-ARC) / spin on carbon hard mask (SOC)) (4 layers process). 4 layers process showed the excellent lithographic performance and pattern transfer performance. In this paper, we will discuss the detail of our approach and materials for 4 layers process.
A frequent problem encountered by photoresists during the manufacturing of semiconductor device is that activating radiation is reflected back into the photoresist by the substrate. So, it is necessary that the light reflection is reduced from the substrate. One approach to reduce the light reflection is the use of bottom anti-reflective coating (BARC) applied to the substrate beneath the photoresist layer. The BARC technology has been utilized for a few years to minimize the reflectivity. As the chip size is reduced to sub 100nm, the photoresist thickness has to decrease with the aspect ratio being less than 3.0. Therefore, new Organic BARC is strongly required which has the minimum reflectivity with thinner BARC thickness and higher etch selectivity toward resists. Hynix Semiconductor Inc., Nissan Chemical Industries, Ltd., and Brewer Science, Inc. have developed the advanced Organic BARC for achieving the above purpose. As a result, the suitable high performance 248nm Organic BARCs, NCA series, were achieved. Using CF4 gas as etchant, the plasma etch rate of NCA series is about 1.4 times higher than that of conventional 248nm resists. NCA series can be minimizing the substrate reflectivity at below 45nm BARC thickness. NCA series show the excellent litho performance and coating property on real device.
The suitable high performances Organic Bottom Anti-Reflective Coatings (Organic BARCs) for 193nm Bilayer system, NCA900 series, were developed. Using CF4 gas as etchant, the etching rate of NCA900 series were 0.87 times slower than that of conventional 193nm photoresists. With NCA900 series, the reflectivity was less than 1% at over 300nm BARC thickness on polysilicon, silicon oxide and silicon nitride. Using conventional 193nm photoresist, 80nm L/S (1:1) patterns with 0.5-micron DOF were observed on NCA900 series. NCA900 series showed the excellent litho performance and coating property. This paper presents the development of BARCs for 193nm Bilayer system.