Area Fill is designed to calculate the area within a window that is covered by metal -- to be more specific, the area that is digitized. Knowing this area can be useful for calculations related to plating and to planarization (CMP).

The program clips the desired data to the window extents, unionizes the data (so that overlapping polygons do not contribute to an incorrect calculation) and then sums up the area of the results.

The output is written as an ASCII table.

Boolean Layer Operations

Often, the metal pattern on the mask/wafer is defined not by a single GDSII data layer but rather by a combination of layers. Area Fill supports the union of layers, subtraction of one layer from another and reversal of layers.

Tiling Area Calculations

Often one needs to calculate a matrix of local area or densities. For example, one may have a total field area of 25 x 25 mm but needs to know the metal density in 50 um increments. Area Fill has a tile argument that allows the user to define the tile size in X and Y.

Perimeter Calculations

It may be of interest to get a measure of the "spatial frequency" of a particular tile. Two tiles might have the same area fill value but tile (a) might have a single fat rectangle and tile (b) might be composed of many tightly spaced narrow lines.

Area Fill can give an single value indication of the frequency by calculating and reporting the x/y components of the conductor perimeters.

Image Output

Some users might like to produce a density "image." The utility afill2tiff can covert the density (and perimeter) data into a TIFF image.