Dynamic Etch Compensation

The Dynamic Etch Compensation DFM action is designed to meet the special need of the HDI (High Density Interconnect) fabricator, where etching process behavior is not uniform.

The Dynamic Etch Compensation action adds copper consistently around existing copper to compensate for uneven etching. Each feature is enlarged by a (compensation) value defined as a function of the feature type, spacing between a feature and its neighbors, and the neighbors' types. Features are enlarged evenly. The compensation stops when minimum spacing is reached or the compensation value is optimal, whichever occurs first.

Predefined Compensation Functions

A new class of system predefined functions (in addition to .zero) was introduced in Genesis v8.1.

.a/b where a and b are non-negative numbers in the current (editor) units. This encodes the following function:

-         the compensation value is 0 for spacing between 0 and a

-         the compensation value is b for spacing greater than a.

In formal language, this functions would be defined as follows:

.comment .a/b system predefined function

.units current editor units (mil/micron)

.maxrule horizontal

.interpolation steps

.points

0 0

a b

Enhancements to Surface Compensation Action

The Surfaces Compensation action was improved to produce much smoother surfaces. When compensating special pads, the action worked on many small, dense surfaces, but produced inferior results. The improved algorithm in the Surfaces Compensation action performs advanced surface smoothing after surfaces compensation has been completed. For an example of the improved action at work, see the before and after pictures below.

Enhancements to Compensation for Standard Pads

Standard pads can be flattened on demand and compensated according to surface compensation rules. This procedure is controlled by the new ERF variable flatten_standard_pads. This ERF variable is similar to the existing ERF variable flatten_special_pads, which controls pad flattening and compensation for special (non-standard) pads.