METHOD FOR RAPID ESTIMATION OF LAYOUT-DEPENDENT THRESHOLD VOLTAGE VARIATION IN A MOSFET ARRAY
First Claim
1. An automated method for estimating layout-induced variations in threshold voltage in an integrated circuit layout, comprising the steps of:
- selecting a diffusion area within the layout for analysis;
identifying Si/STI edges on the selected area;
identifying channel areas and their associated gate/Si edges;
determining threshold voltage variations in each identified channel area, including the steps ofcalculating threshold voltage variations due to effects in a longitudinal direction;
calculating threshold voltage variations due to effects in a transverse direction;
combining the longitudinal and transverse variations to provide an overall variation; and
determining a total variation by combining variations from individual channel variations.
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Abstract
An automated method for estimating layout-induced variations in threshold voltage in an integrated circuit layout. The method begins with the steps of selecting a diffusion area within the layout for analysis. Then, the system identifies Si/STI edges on the selected area as well as channel areas and their associated gate/Si edges. Next, the threshold voltage variations in each identified channel area are identified, which requires further steps of calculating threshold voltage variations due to effects in a longitudinal direction; calculating threshold voltage variations due to effects in a transverse direction; and combining the longitudinal and transverse variations to provide an overall variation. Finally, a total variation is determined by combining variations from individual channel variations.
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Citations
18 Claims
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1. An automated method for estimating layout-induced variations in threshold voltage in an integrated circuit layout, comprising the steps of:
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selecting a diffusion area within the layout for analysis; identifying Si/STI edges on the selected area; identifying channel areas and their associated gate/Si edges; determining threshold voltage variations in each identified channel area, including the steps of calculating threshold voltage variations due to effects in a longitudinal direction; calculating threshold voltage variations due to effects in a transverse direction; combining the longitudinal and transverse variations to provide an overall variation; and determining a total variation by combining variations from individual channel variations. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A system for automated estimation of layout-induced variations in threshold voltage in an integrated circuit layout, comprising:
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a digital computer, including a processor, display means and data storage means; a computer program, stored on the data storage means, configured to perform the steps of selecting a diffusion area within the layout for analysis; identifying Si/STI edges on the selected area; identifying channel areas and their associated gate/Si edges; determining threshold voltage variations in each identified channel area, including the steps of calculating threshold voltage variations due to effects in a longitudinal direction; calculating threshold voltage variations due to effects in a transverse direction; combining the longitudinal and transverse variations to provide an overall variation; and determining a total variation by combining variations from individual channel variations. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A system for automated estimation of layout-induced variations in threshold voltage in an integrated circuit layout, comprising:
computer program means, stored on the data storage means, for selecting a diffusion area within the layout for analysis; identifying Si/STI edges on the selected area; identifying channel areas and their associated gate/Si edges; determining threshold voltage variations in each identified channel area, including the steps of calculating threshold voltage variations due to effects in a longitudinal direction; calculating threshold voltage variations due to effects in a transverse direction; combining the longitudinal and transverse variations to provide an overall variation; and determining a total variation by combining variations from individual channel variations. - View Dependent Claims (14, 15, 16, 17, 18)
Specification