Extreme ultraviolet lithography process and mask
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsShinn-Sheng Yu, Yen-Cheng Lu, Anthony Yen
Life of this patent
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Abstract
A process of an extreme ultraviolet lithography (EUVL) is disclosed. The process includes receiving an extreme ultraviolet (EUV) mask with multiple states. Different states of the EUV mask are assigned to adjacent polygons and a field. The EUV mask is exposed by a nearly on-axis illumination (ONI) with partial coherence σ less than 0.3 to produce diffracted lights and non-diffracted lights. Most of the non-diffracted lights are removed. The diffracted lights and the not removed non-diffracted lights are collected and directed to expose a target by a projection optics box.
Claims20
An extreme ultraviolet lithography (EUVL) process, comprising:
- receiving an extreme ultraviolet (EUV) mask with multiple states, wherein said multiple states of the EUV mask are assigned to adjacent polygons and a field, wherein the field is a region without polygons;
- exposing the EUV mask by a nearly on-axis illumination (ONI) with partial coherence σ less than 0.3 to produce diffracted lights and non-diffracted lights;
- removing at least a portion of the non-diffracted lights;
- and
- collecting and directing the diffracted lights and the not removed non-diffracted lights by a projection optics box (POB) to expose a target.
An extreme ultraviolet lithography (EUVL) process, comprising:
- receiving an EUV mask with three states;
- and
- assigning different said states of the EUV mask to adjacent polygons and a field, wherein the field is a region without polygons;
- exposing the EUV mask by a nearly on-axis illumination (ONI) with partial coherence σ less than 0.3 to produce diffracted lights and non-diffracted lights;
- removing more than 70% of the non-diffracted lights;
- collecting and directing the diffracted lights and the not removed non-diffracted lights by a projection optics box (POB) to expose a semiconductor wafer.
An extreme ultraviolet lithography (EUVL) mask, comprising:
- a low thermal expansion material (LTEM) substrate;
- a reflective multilayer (ML) above one surface of the LTEM substrate;
- a conductive layer above an opposite surface of the LTEM substrate;
- a capping layer above the reflective ML;
- a buffer layer above the capping layer;
- an absorption stack above the buffer layer, wherein the absorption stack comprises multiple layers;
- and
- multiple patterning on the absorption stack to form multiple states, wherein different said states are assigned to adjacent polygons and a field.
Dependencies are inferred from the claim text.