Method and System For Optimizing Sub-Nanometer Critical Dimension Using Pitch Offset
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsChih-Ming Ke, Shinn-Sheng Yu, Yu-Hsi Wang, Jacky Huang, Tsai-Sheng Gau, Kuo-Chen Huang
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Abstract
A method and a system are provided for calibrating metrological tools used to measure features of a semiconductor device. A critical dimension (CD) ruler defines a known pitch plus a pitch offset. A photoresist layer is measured to determine a measured pitch whereupon the measured pitch is compared to the known pitch. From the comparison, appropriate calibration steps can be taken to reduce the difference between the known pitch and the measured pitch.
Claims20
A method comprising:
- measuring a first pitch;
- measuring a second pitch that is offset from the first pitch by a pitch offset value;
- comparing the first pitch and the second pitch;
- and
- determining metrological accuracy of a metrology system from the comparison.
A method for metrological calibration, comprising:
- forming a material layer to have a first material line and a second material line, wherein a known pitch between the first material line and the second material line includes a sub-nanometer offset value;
- measuring the material layer to determine a measured pitch between the first material line and the second material line;
- determining a difference between the measured pitch and the known pitch;
- and
- determining calibration needed for a metrological tool used for the measuring to reduce a difference between the measured pitch and the known pitch.
An apparatus comprising:
- a first set of material lines having a baseline pitch;
- and
- a second set of material lines having a second pitch that includes the baseline pitch and a pitch offset that is less than the baseline pitch.
Dependencies are inferred from the claim text.