Design Guidelines: Supported Bridges

An integral part of any circuit design are couplers (including Lange couplers) and spiral inductors.  These structures can be a challenge to the assembly process and a source of common damage during manufacturing and testing.  Wire bonding these features also introduces inconsistency in the design which can result in more tuning and variability, especially over broad frequency ranges.  Long an industry standard, we offer supported bridges—a consistent, reliable way to incorporate these structures. We can also test these features to ensure performance prior to integrating high cost active devices.

Fine Line Conductor Standard Layout Guidelines

Feature Values and Tolerances Comments
line spacing

.0004" minimum ± .0001"

Minimum space width available in TiW films only

line width

.0005" minimum ± .0001"

Minimum line width available in TiW films only

bridge width

.001" minimum

.0001" Bridge/Conductor Pullback

bridge contact area

.001" square minimum


bridge span

.003" minimum


bridge support

.0015" x .003"

.0025" overlap, insulator to conductor

dielectric layer

width + .006", span + .008"

may be deleted at factories discretion on small bridges

bridge height

200 microinches minimum

250 ±50 microinches typical

250 microinches minimum

300 ± 50 microinches typical

span width

6:1 maximum