Compensation of reticle flatness on focus deviation in optical lithography
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsLee-Chih Yeh, Hsin-Chang Lee, Chia-Jen Chen, Tzu-Yi Wang
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Abstract
A method for lithography patterning includes providing a mask for photolithography patterning; measuring a mask flatness of the mask; calculating focal deviation of imaging the mask to a substrate in a lithography apparatus; adjusting the lithography apparatus to have a compensated focal plane of the mask based on the focal deviation; and exposing the semiconductor substrate utilizing the mask and the lithography apparatus with adjusted focal plane.
Claims17
A method for lithography patterning, comprising:
- providing a mask for photolithography patterning;
- measuring a mask flatness of the mask using one of liquid crystal display imaging and optical reflection;
- calculating a focal deviation of imaging the mask to a substrate in a lithography apparatus, wherein the focal deviation is calculated using measured mask flatness data from a main pattern region of the mask, and wherein the calculating of the focal deviation comprises utilizing a linear fit, wherein the linear fit comprises a regression equation of f=a*m+b in which f stands for the focal deviation, m stands for the mask flatness, and a and b are constant parameters;
- adjusting the lithography apparatus to have a compensated focal plane of the mask based on the focal deviation;
- and
- exposing the semiconductor substrate utilizing the mask and the lithography apparatus with the adjusted focal plane.
A lithography apparatus, comprising:
- a lens system;
- a substrate stage configured to secure a substrate for receiving a radiation energy through the lens system, and designed operable to support relative movement between the substrate and the lens system;
- a mask flatness metrology tool integrated in the lithography apparatus and configured to measure mask flatness of a mask having a pattern to be transferred to the substrate using one of liquid crystal display imaging and optical reflection;
- and
- a control module configured to be capable of:
- calculating a focal deviation of the mask based on the measured mask flatness in a main pattern region of the mask, wherein the calculating of the focal deviation comprises utilizing a linear fit, wherein the linear fit comprises a regression equation of f=a*m+b in which f stands for the focal deviation, m stands for the mask flatness, and a and b are constant parameters;
- and
- adjust the lens system to compensate the focal deviation accordingly.
A method for lithography patterning, comprising:
- measuring a mask flatness of a mask using a mask flatness metrology tool using one of liquid crystal display imaging and optical reflection;
- calculating focal deviation of imaging the mask to a substrate in a lithography apparatus, wherein the focal deviation is calculated using measured mask flatness data from a main pattern region of the mask, and wherein the calculating of the focal deviation comprises utilizing a linear fit, wherein the linear fit comprises a regression equation of f=a*m+b in which f stands for the focal deviation, m stands for the mask flatness, and a and b are constant parameters;
- and
- adjusting the lithography apparatus to have a compensated focal plane of the mask based on the focal deviation.
Dependencies are inferred from the claim text.