Photomasking
AssigneeIntel Corporation, a Delaware corporation
InventorPei-Yang Yan
Life of this patent
Estimating the term…
Abstract
An attenuated phase-shifting photomask (APSM) provides adjustment of attenuation from mask to mask. The APSM includes a multilayer substrate, a buffer thin film coupled to the substrate, and a top layer thin film on top of the buffer thin film. The thin films are etched with a circuit pattern to form a photomask, and are chosen to have certain thicknesses which would provide adjustment of attenuation within a specified attenuation operating range and appropriate phase shift without changing said buffer thin film and said top layer thin film.
Claims11
An article comprising a machine-readable medium storing instructions operable to cause one or more machines to perform operations comprising:
- determining a first thickness of a particular material and a second thickness of another material to attenuate light of a particular wavelength by a desired attenuation amount as the light is transmitted through the particular material and the another material in a forward direction and in a reflected direction, the first thickness of the particular material and the second thickness of the another material to shift a phase of the light by a desired phase amount as the light is transmitted through the particular material and the another material in the forward direction and in the reflected direction;
- depositing a first film on top of a substrate, said first film having the first thickness of the particular material;
- and
- depositing a second film on top of the first thin film, the second film having the second thickness of the another material.
A process for fabricating an integrated-circuit wafer comprising:
- depositing an electrically conducting material on top of said wafer;
- coating a photosensitive resist on top of said conducting material;
- patterning the photosensitive resist using an attenuated phase-shifting mask, wherein the patterning comprises:
- receiving input light having a phase and an amplitude at a first surface of the mask;
- shifting the phase and reducing the amplitude in a layer of the mask, the layer comprising a first thickness of a first material, the first thickness selected to obtain a pre-selected attenuation;
- further shifting the phase and further reducing the amplitude in another layer of the mask, the another layer comprising a second thickness of a second material, the second thickness selected to obtain the pre-selected attenuation;
- reflecting at least a portion of the light from one or more substrate layers of the mask;
- further shifting the phase and further reducing the amplitude in the another layer of the mask;
- further shifting the phase and further reducing the amplitude in the layer of the mask;
- and
- transmitting output light from the mask to the resist, the output light having an output phase about 180 degrees different than the phase, the output light having an output amplitude corresponding to the pre-selected attenuation;
- etching said conducting material;
- and
- stripping said resist.
Dependencies are inferred from the claim text.