NOVELTY - The method comprises forming a layer of dry-etchable material on a surface of a hard-to-dry etch substrate (310), dry etching the dry-etchable material, and forming an etch-resistant mask. The dry-etchable material: has similar material properties to the hard-to-dry- etch substrate material and similar index of refraction and similar coefficient of thermal expansion (CTE) compared to the hard-to-dry-etch substrate; and does not produce substantial quantities of non-volatile etch byproducts that redeposit when the dry-etchable material is subject to the dry etching.    USE - The method is useful for dry-etching a hard-to-dry-etch substrate material (claimed) such as metals, semiconductors including silicon or insulators including quartz, where the substrate is useful for architectural glass for windows, information displays or flat panel displays and solar panels.    ADVANTAGE - The method is capable of accurately dry-etching the hard-to-dry-etch substrate material in an easy manner thus improving the efficiency of the solar panels.    DETAILED DESCRIPTION - The method comprises forming a layer of dry-etchable material on a surface of a hard-to-dry etch substrate (310), dry etching the dry-etchable material, and forming an etch-resistant mask. The dry-etchable material: has similar material properties to the hard-to-dry- etch substrate material and similar index of refraction and similar coefficient of thermal expansion (CTE) compared to the hard-to-dry-etch substrate; does not produce substantial quantities of non-volatile etch byproducts that redeposit when the dry-etchable material is subject to the dry etching; and is etched through a pattern in a masking material. The hard-to-etch substrate material is a commercially available glass. The step of dry-etching the dry-etchable material includes dry-etching the dry-etchable material in a manner that forms tapered or re-entrant features. The step of forming the etch-resistant mask includes providing a radiation sensitive layer (308) on a top surface of the dry-etchable material, providing a rotatable mask configured to selectively prevent a portion of the radiation sensitive layer from being exposed to radiation passing through the mask, and rolling the mask over a surface of the radiation sensitive layer while passing radiation through the mask to create an image in the radiation sensitive layer. An outer surface of the rotatable mask is: configured to deform when in rolling contact with a surface of the radiation sensitive layer; and a conformable outer surface, which conforms to the radiation-sensitive layer on the substrate surface. The rotatable mask: includes features having a size of 10-100 nm; is a phase-shifting mask, which causes the radiation to form an interference pattern in the radiation sensitive material; employs surface plasmon behavior; and is a cylinder and a phase shifting mask, which is present as a relief on a surface of the transparent cylinder and present on a layer applied over a surface of the cylinder. The conformable outer surface is a shaped or nano structured polymeric material. The cylinder has a flexible wall, where the cylindrical shape is deformed upon contact with the radiation sensitive material. The substrate is moved in a direction toward or away from a contact surface of the rotatable cylinder during distribution of radiation from the contact surface of the cylinder. The cylinder is rotated on the substrate while the substrate is static. The rotatable mask and the substrate surface are moved independently, where movement of the rotatable mask and the substrate surface are synchronized with each other. The pattern in the masking material includes features with sloped or non-sloped walls. The hard-to-dry-etch substrate acts as an etch stop for the dry etching of the dryetchable material. An INDEPENDENT CLAIM is included for a composition of matter comprising a hard to dry-etch substrate.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic cross-sectional view of patterning a hard-to-dry-etch substrate.    Dry-etchable layer (306')    Radiation sensitive layer (308)    Substrate. (310)