Optical Proximity Correction OPC Calculator

Computational lithography & photomask synthesis: Model line-end pullback (foreshortening), iso-dense proximity bias, corner rounding, and serif compensation geometry.

Mask Feature & Optical Setup

Target Line Width W (nm): Target on-wafer polygon width

Target Line Length L (nm): Target polygon length

Pattern Environment: Neighboring proximity density

Optical Blur / Diffusion σ (nm): Airy disk / resist acid blur

Resist Threshold Intensity I_th: Dose-to-clear intensity threshold

OPC Serif Type: Geometric correction method

Proximity Distortion & Correction

Uncorrected Line-End Pullback (ΔL)

Recommended OPC Bias / Extension

Iso-Dense Proximity Bias (ΔW)

Diffraction optical bias

Corner Rounding Radius (R_corner)

Low-pass spatial filtering

Corrected Mask Reticle CD (4×)

On 4× reduction reticle

Aerial Image Slope (NILS)

Normalized Image Log Slope

Recommended Tools & Equipment

Tested hardware and components for high reliability

100% Free Tool Zero Sign-Up

Frequently Asked Questions

What is the difference between Rule-Based and Model-Based OPC?

Rule-based OPC uses lookup tables of predefined geometric offsets based on feature width and spacing. Model-based OPC runs iterative numerical simulations of the optical transmission cross-coefficients (TCC) and resist reaction-diffusion to minimize edge placement error (EPE).

What is Inverse Lithography Technology (ILT)?

ILT frames photomask design as an inverse mathematical problem: given the desired silicon wafer target contour, it optimizes the mask transmission function pixel-by-pixel, producing organic-looking curvilinear mask shapes.

Why are optical masks fabricated at 4× reduction?

Modern projection steppers use 4× optical reduction optics. A 28 nm feature on the silicon wafer corresponds to a 112 nm feature on the quartz reticle photomask, loosening mask e-beam writing tolerances and defect inspection requirements.