US 12,468,219 B2
Method for forming photomask
Pin Han Huang, Tainan (TW)
Assigned to United Microelectronics Corp., Hsinchu (TW)
Filed by United Microelectronics Corp., Hsinchu (TW)
Filed on Jul. 26, 2022, as Appl. No. 17/873,165.
Claims priority of application No. 111122798 (TW), filed on Jun. 20, 2022.
Prior Publication US 2023/0408900 A1, Dec. 21, 2023
Int. Cl. G03F 1/36 (2012.01); G03F 1/70 (2012.01); G03F 7/00 (2006.01)
CPC G03F 1/36 (2013.01) [G03F 1/70 (2013.01); G03F 7/705 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A method for forming a photomask, comprising:
providing a photomask pattern according to a target pattern;
simulating a first light intensity curve according to the photomask pattern;
subjecting the first light intensity curve to a check on light intensities at pattern edges of the target pattern to define a light intensity error, wherein the light intensity error is a difference between the light intensities of the first light intensity curve corresponding to the pattern edges of the target pattern and a predefined standard light intensity;
correcting the photomask pattern to reduce the light intensity error;
identifying a lithography weak region in the target pattern;
obtaining a second light intensity curve of the lithography weak region by simulation;
subjecting the second light intensity curve to a check on peak light intensity to define a peak intensity error, wherein the peak intensity error is a difference between a peak value of the second light intensity curve and a predetermined peak value;
retargeting the target pattern to reduce the peak intensity error; and
re-correcting the photomask pattern according to the retargeted target pattern.