Methods of forming photomasks

A method of forming a photomask, comprising:

• forming a phase-shifting material over a transparent material base;
• forming two or more additional materials over the phase-shifting material;
• the phase-shifting material together with the two or more additional materials forming a light-attenuating stack;
• removing portions of the light-attenuating stack to leave segments of the light-attenuating stack remaining over the transparent material as a mask pattern, the mask pattern comprising a pair of adjacent features;
• said features comprising horizontal top surfaces, and comprising vertical sidewall surfaces that extend downwardly from the top surfaces to the base;
• the vertical sidewall surfaces extending along all of the materials of the light-attenuating stack;
• the adjacent features being spaced apart from one another by a gap, a horizontal surface of the base being exposed within said gap;
• coating the horizontal top surfaces of the features, the horizontal surface of the base, and the vertical sidewall surfaces of the features with a coating material;
• and
• utilizing an etch to remove the coating material from along the horizontal top surfaces of the features and/or along the horizontal surface of the base, while leaving the coating material along the vertical sidewall surfaces of the features.