Multi-Chip Module Design, Verification, and Yield Optimization Using AWR Software
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Layer-Based Shape Modifiers
To elaborate on layer-based shape modifiers, when looking at the spiral inductor on the left in Figure 3, it can be seen that the
metals are all the same width and, in addition, are all aligned with each other in the Z axis. It can be seen that there is no
registration error. In the spiral inductor on the right, however, the layers have shifted independently of one another in the X
and Y axis. In addition, the pink one has become thicker and the gold one has become thinner. These issues correspond to the
registration error as well as the over/under etch.
Figure 3: Metals are the same width/aligned on the Z-axis in the spiral inductor (left), and layers have shifted in X/Y independently of one
another (right)
For each layer, there might be one modifier and then the amount that it moves each layer can be assigned a parameter based
on a statistical variation, as shown in Figure 4.
Figure 4: Statistical variation for each layer
Statistical Parameters
Setting up the statistical variation for the dielectric constant in this module example is also quite easy. The designer need
only indicate that this variable is enabled for statistics, specify a distribution type, and assign it a standard deviation or
variation percentage. This variable is then used in the material stack-up profile. When a yield analysis is performed, the value
of the dielectric constant will assume a value based on its statistical variation.
Visual Inspection with Connectivity
When manipulating layers, as is done with the layer-based modifiers feature, incorrect numbers can be entered that result in
shorts or opens in the circuit. The connectivity highlighter tool in AWR Microwave Office software shows if the metal connec-
tivity is changing, enabling designers to ensure that there are no opens or shorts in the circuit prior to simulation. (Figure 5).
Figure 5: The connectivity highlighter in AWR Microwave Office software highlights if the metal connectivity is changing to ensure there are no
opens or short in the circuit when using the layer modifiers tool
