Automated Design for Micromachining

# Fill Donut

## Introduction

Often, one would like to fill a circle or donut with etch holes, dimples, or other simple repetitive structure. This parameterized cell provides a simple approach to filling a circle or donut with regularly spaced sub-rectangles or sub-circle.

The cell supports two types of fills: Type A and Type B. Type A fills are used, for example, for etch holes. The sub-rectangle or sub-circles are placed so that they are equidistant from each other, and the edges.

Type B fills are used, for example, for placing dimples. The dimples are equidistant from each other, but the distance between the edges of the rectangle and the nearest dimples is half the distance between the dimples

The fill rectangle parameterized cell is closely related.

## Theory

Please refer to the documentation for the fill rectangle parameterized cell.

## Parameters

Any parameter may be modified, if necessary, to meet design rules. Typically, this involves increasing parameters that specify distances, so that minimum line width and minimum line spacing rules will not be violated. This has been extended to the convention of specifying a zero for some parameters to obtain an instance of the minimum size.

In addition to the parameters listed below, several technology parameters also influence the implementation of parameterized cells. This data must be present in the technology library.

Table 1: Parameters for the 'fill_donut' parameterized cell.
Name Description Range Units
inner radius The inner radius of the donut to be filled. If a circle is to be filled, set the inner radius to zero. [0,∞) um
outer radius The outer radius of the donut to be filled. [inner radius,∞) um
spacing This parameter specifies the maximum distance between sub-figures. However, the parameterized cells will try to minimize the number of sub-figures while ensuring that this limit is respected. [0,∞) um
layer_a The drawing layer used to create the sub-figures used for fill Type A. If blank, then nothing will be drawn for this fill type. dwg layers -
size_a This parameter is the width of the sub-rectangle or the diameter of the sub-circles, depending on which is selected. [0,∞) um
is_circle_a If true, then the sub-figures for fill Type A will be circles. Otherwise, the rectangle will be filled with sub-rectangles. true/false -
layer_b The drawing layer used to create the sub-figures used for fill Type B. If blank, then nothing will be drawn for this fill type. dwg layers -
size_b This parameter is the width of the sub-rectangle or the diameter of the sub-circles, depending on which is selected. [0,∞) um
is_circle_b If true, then the sub-figures for fill Type B will be circles. Otherwise, the rectangle will be filled with sub-rectangles. true/false -

## References

The documentation for this parameterized cell does not contain any references.