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 for patterning a target, comprising:
- providing an extreme ultraviolet (EUV) mask having an absorption stack disposed on a reflective multilayer (ML), wherein the absorption stack provides multiple reflective states including a first reflective state and a second reflective state, wherein the first reflective state is provided by an exposed top surface of a first absorption stack layer and the second reflective state is provided by an exposed top surface of a second absorption stack layer;
- illuminating the EUV mask with an EUV light source providing an incident beam of a nearly on-axis illumination (ONI) with partial coherence σ less than 0.3;
- reflecting the incident beam from the EUV mask thereby producing diffracted light and non-diffracted light using the multiple reflective states of the EUV mask;
- removing a portion of the reflected, non-diffracted light;
- and
- collecting and directing the reflected, diffracted light and an unremoved portion of non-diffracted light with a projection optics box (POB) to expose the target.
An extreme ultraviolet lithography (EUVL) process for patterning a semiconductor wafer, comprising:
- patterning an extreme ultraviolet (EUV) mask that has an absorber layer with multiple material layers to provide multiple reflective states by removing portions of the multiple material layers of the absorber layer, wherein the removing portions provides for exposing a top surface of at least two different layers of the multiple material layers of the absorber layer thereby providing a first reflective state and a second reflective state;
- delivering a radiation beam to the EUV mask using an EUV light source wherein the radiation beam has a nearly on-axis illumination (ONI) with partial coherence σ less than 0.3;
- reflecting the delivered radiation beam, wherein the EUV mask having multiple reflective states produces diffracted light and non-diffracted light;
- removing a portion of the non-diffracted light, the portion comprising more than 70% of the non-diffracted light;
- and
- collecting and directing the diffracted light and an unremoved portion of the non-diffracted light by a projection optics box (POB) to expose the semiconductor wafer.
A method for fabricating an extreme ultraviolet (EUV) lithography mask, the method comprising:
- forming a multilayer structure over a mask substrate;
- depositing a buffer layer over the multilayer structure;
- depositing a first absorption stack layer over the buffer layer, a second absorption stack layer over the first absorption stack layer, and a third absorption stack layer over the second absorption stack layer;
- patterning the first, second, and third absorption stack layers to provide a first reflective state at a top surface of the buffer layer;
- and
- patterning the third absorption stack layer to provide a second reflective state at a top surface of the second absorption stack layer, a third reflective state being provided by a top surface of the third absorption stack layer.
Dependencies are inferred from the claim text.