| 摘要 |
Transfer mask blanks and masks made using such blanks are disclosed that exhibit minimal tensile stress. Such mask blanks and masks exhibit minimal membrane distortion and pattern deformation whenever a pattern is formed on a membrane of the mask blank. After fabrication, the transfer mask blank is annealed in a N2 atmosphere to reduce the variation in boron concentration to 10% or less through the thickness dimension of the silicon membrane. The resulting uniformity in boron concentration within the silicon membrane reduces tensile stress, which in turn reduces pattern deformation. The silicon membrane is boron doped at a boron concentration in a range of 2x1019 to 5x1020 atoms/cm3. This enables the silicon membrane to act as an etch barrier for anisotropic etching using KOH solution. |
