The present invention provides a method and apparatus for etching a photomask substrate with enhanced process monitoring, for example, by providing for optical monitoring at certain regions of the photomask to obtain dual endpoints, e.g., etch rate or thickness loss of both a photoresist layer and an absorber layer. By monitoring transmissity of an optical beam transmitted through areas having photoresist layer and etched absorber layer at two different predetermined wavelength, dual process endpoints may be obtained by a signal optical detection.

In some embodiments, a patterned photomask has a plurality of shielding layers. In some embodiments, a photomask for mask patterning is described. The photomask includes a phase shift layer overlying a transparent layer. The photomask also includes a first shielding layer overlying the phase shift layer. The first shielding layer has a first thickness and a first optical density. The photomask further includes a second shielding layer overlying the first shielding layer. The second shielding layer has a second thickness and a second optical density. The second thickness is less that than the first thickness and the second optical density is less than the first optical density.

In some embodiments, a patterned photomask has a plurality of shielding layers. In some embodiments, a photomask for mask patterning is described. The photomask includes a phase shift layer overlying a transparent layer. The photomask also includes a first shielding layer overlying the phase shift layer. The first shielding layer has a first thickness and a first optical density. The photomask further includes a second shielding layer overlying the first shielding layer. The second shielding layer has a second thickness and a second optical density. The second thickness is less that than the first thickness and the second optical density is less than the first optical density.

A mask for photolithography includes: a transparent substrate; a phase shift pattern on the transparent substrate and configured to change a phase of light; a dielectric layer on the transparent substrate; and a negative refractive-index meta material layer on the dielectric layer.

A mask for photolithography includes: a transparent substrate; a phase shift pattern on the transparent substrate and configured to change a phase of light; a dielectric layer on the transparent substrate; and a negative refractive-index meta material layer on the dielectric layer.

A halftone phase shift film containing Si and N and/or O is deposited on a transparent substrate by reactive sputtering of a Si-containing target with a reactive gas containing N and/or O. One layer is sputter deposited while the reactive gas flow rate is set equal to or lower than the lower limit of the reactive gas flow rate in the hysteresis region, and another layer is sputter deposited while the reactive gas flow rate is set inside the lower and upper limits of the reactive gas flow rate in the hysteresis region. The phase shift film exhibits satisfactory in-plane uniformity of optical properties.

A halftone phase shift film containing Si and N and/or O is deposited on a transparent substrate by reactive sputtering using a silicon-containing target with a reactive gas. Different powers are applied across a plurality of targets so that two different sputtering modes selected from metal, transition and reaction modes associated with a hysteresis curve are applied to the targets. The phase shift film exhibits satisfactory in-plane uniformity of optical properties.

A halftone phase shift film containing Si and N and/or O is deposited on a transparent substrate by reactive sputtering using a silicon-containing target with a reactive gas. Different powers are applied across a plurality of targets so that two different sputtering modes selected from metal, transition and reaction modes associated with a hysteresis curve are applied to the targets. The phase shift film exhibits satisfactory in-plane uniformity of optical properties.

The present application relates to a method for permanently repairing defects of absent material of a photolithographic mask, comprising the following steps: (a) providing at least one carbon-containing precursor gas and at least one oxidizing agent at a location to be repaired of the photolithographic mask; (b) initiating a reaction of the at least one carbon-containing precursor gas with the aid of at least one energy source at the location of absent material in order to deposit material at the location of absent material, wherein the deposited material comprises at least one reaction product of the reacted at least one carbon-containing precursor gas; and (c) controlling a gas volumetric flow rate of the at least one oxidizing agent in order to minimize a carbon proportion of the deposited material.

The present application relates to a method for permanently repairing defects of absent material of a photolithographic mask, comprising the following steps: (a) providing at least one carbon-containing precursor gas and at least one oxidizing agent at a location to be repaired of the photolithographic mask; (b) initiating a reaction of the at least one carbon-containing precursor gas with the aid of at least one energy source at the location of absent material in order to deposit material at the location of absent material, wherein the deposited material comprises at least one reaction product of the reacted at least one carbon-containing precursor gas; and (c) controlling a gas volumetric flow rate of the at least one oxidizing agent in order to minimize a carbon proportion of the deposited material.