Accurate Critical Dimension Control Research Articles

Reflectivity Control at Substrate / Photoresist Interface by Inorganic Bottom Anti-Reflection Coating for Nanometer-scaled Devices

More accurate CD (Critical Dimension) control is required for the nanometer-scaled devices. However, since the reflectivity between substrate and PR (Photoresist) becomes higher, the CD (Critical Dimension) swing curve was intensified. The higher reflectivity also causes PR notching due to the pattern of sub-layer. For this device requirement, it was optimized for the thickness, refractive index(n) and absorption coefficient(k) in the bottom anti-reflective coating(BARC; SiON) and photoresist with the minimum reflectivity. The computational simulated conditions, which were determined with the thickness of 33 nm, n of 1.89 and k of 0.369 as the optimum condition, were successfully applied to the experiments with no standing wave for the 0.13um-device. At this condition, the lowest reflectivity was 0.44%. This optimum condition for BARC SiON film was applied to the process for 0.13um-device. The optimum SiON film as BARC to PR and sub-layer could be formed with the accurate CD control and no standing waver for the nanometer-scaled semiconductor manufacturing process.

Advanced CD Control Technology for 65-nm Node Dual Damascene Process

This paper describes an advanced critical dimension (CD) control technology for a 65-nm node dual damascene process and beyond. A newly developed deposition enhanced shrink etching (DESE) process was introduced into both via and trench etching. This technology realizes not only dynamic via shrink ranging 40 nm but also accurate trench CD control by feedforward technology. Etching performance was investigated by electrical results of 65-nm Cu/low-k interconnects using porous chemical-vapor deposition SiOC. The 100% yields of 60-M via chains verified the DESE process robustness.

New Gate CD Control Technology Using CF$_{4}$ Plasma Treatment Following HBr/O$_{2}$ Plasma Treatment Step in Gate Etch Process Using Organic BARC

A new technology of resist trimming in a gate etch process using organic bottom antireflective coating (BARC) for accurate and stable gate critical dimension (CD) control of sub-0.18-mum node technology is presented in this paper. The new method uses an in situ CF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> plasma treatment following an HBr/O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> plasma treatment step as a part of the gate etch process to achieve a stable gate CD. The new method controls gate CD by trimming the photo resist masking gate line by reducing the effect of etch by-products, the source of CD variation, after etching organic BARC with HBr/O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> plasma. It shows the markedly improved gate CD capability over the conventional one using just an HBr/O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> plasma treatment for the CD control. We confirm that this new method is very useful and effective for the accurate gate CD control for sub-0.18-mum node metal-oxide semiconductor technology

Evaluation of new x-ray stepper, the XRA

The exposure performance has been evaluated for the new x-ray stepper, the XRA, which is equipped with global alignment and magnification correction systems. Dose uniformity in the exposure field of 3.9%, stage accuracy of less than 20 nm, and good linearity and stability between the magnification change and applied force were obtained. For the 100 nm node, both critical dimension (CD) control of 10 nm and overlay accuracy of less than 30 nm were obtained using two 4 Gbit masks of the gate and contact hole by the double exposure method. Possible improvements of the dose uniformity and mask pattern CD will result in more accurate CD control. By compensating for the alignment offset, overlay accuracy of 23 nm for the 70 nm node is also expected.

Accurate critical dimension control by using an azide/novolak resist process for electron-beam lithography

Nanofabrication with accurate critical dimension control was investigated with a nonchemically amplified resist. The resist consists of 3,3′-dimethoxy-4,4′-diazidobiphenyl and cresol novolak (novolak). By using novolak with a small weight-average molecular weight (Mw), small resist surface roughness (nano edge roughness) was significantly suppressed down to 3 nm. Nanofabrications of 20-nm lines and spaces (L and S) and 20-nm dot patterns had been demonstrated with the resist. The pattern line-width linearity, the minimum size that the fabricated patterns width were equal to the designed ones, was also preserved down to 30-nm L and S. We investigated use of electron-beam/optical lithography to enhance throughput in nanofabrication. Fine gate structure of 70 nm with a large pad was demonstrated with the hybrid exposure.