Photolithography Development

Physical Effects/Overview of Mechanism:

Under photolithography, a pattern mask is placed on a silicon wafer, and exposed to light. The aerial image determines the cross-linking bond strength at various spots. This yields an etch rate as a function of position, Under the final step, known as photolithography development, the material is etched away, thus the speed function F which gives the speed of the interface in its normal direction is purely a function of position.

Fast Marching Methodology:

In this case, we may use the fast marching method, which provides for an extremely fast solution of the Eikonal equation.

Sample Simulations:

In the figure on the left, we use a model Gaussian function which is radially symmetric of the form


In the figure on the right, we use a masking pattern given in the figure, using an I-line stepper, numerical aperture 0.6. The rate function is calculated using the three-dimensional exposure and post-exposure bake modules of TMA's Depict 4.0, and this is coupled to our fast marching level set method.

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Evolution of single contact hole Evolution under mask pattern
Model Gaussian rate function Rate calculated using TMA's Depict

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