Low $k_{1}$ Contact Hole Formation by Double Line and Space Formation Method with Contact Hole Mask and Dipole Illumination

概要

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The double line and space (L&S) formation method was proved to have the capability to form contact hole (C/H) patterns with high resolution and wide process windows. The drawback of the method is its high cost. By replacing two L&S masks by one C/H mask with dipole illumination, high performance and mask cost reduction were targeted. The 75 nm (0.33-$k_{1}$) $1:1$ C/H pattern and the 70 nm (0.31-$k_{1}$) $1:1$ C/H pattern could be formed by the method using one C/H mask instead of two L&S masks. More than 300 nm depth of focus was obtained at 8% exposure latitude with 10% CD tolerance for the box windows both in the first-layer and the second-layer L&S resist patterns. To form a random C/H pattern on grids, a selective opening resist pattern was formed on the $1:1$ C/H pattern. C/Hs were unearthed by the selective opening patterns with sufficient resist thickness for etching. Thus, random C/Hs on grids could be formed by the combination of the double L&S pattern formation method and the "pack and cover process".
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physicsの論文
2006-06-30