SignalSeal

 

SignalSeal is a high reliability environmental coating for radio frequency (RF) and microwave electronics devices that can be applied to bare die and complete assemblies. GVD’s coatings are applied through a dry, room-temperature vapor deposition process that gently encapsulates RF boards and/or components in a micron-thin polymer. The coating’s low dielectric constant and low thickness has been demonstrated to have negligible impact on RF signal integrity when applied directly to the surface of Monolithic Microwave Integrated Circuits (MMICs) operating in Ku, Ka, and W bands, as validated by independent testing. SignalSeal's high thermal stability makes it compatible with hot-running semiconductor technologies, such as gallium nitride (GaN) components.

RF Compatibility

GVD’s SignalSeal coating has an extremely low dielectric constant and loss tangent; this coupled with the coating’s low thickness (~1 micron) results in virtually no impact to RF performance. This becomes ever more important as the operating frequency of the device being coated increases as the immediate dielectric environment surrounding the circuit creates a more significant impact. For instance, a RF device operating at C band can accommodate a parylene coating with a low impact on signal performance; however, a Ka band device operating at 40 GHz coated with parylene would see such a large performance shift to render the device unusable. This performance impact due to conventional conformal coatings is typically seen starting at X-band (8-12 GHz) and increases over higher RF frequencies, at which point hermetic packaging is seen as the only high-reliability option for environmental protection. This low performance impact when applied directly over the RF circuit enables a chip, component, or assembly designer to consider high-reliability environmental protection without the added weight, volume, and expense of hermetic packaging.

Effective Protection

GVD’s SignalSeal coating has demonstrated high-reliability environmental protection of electronic components in harsh environments. RF devices coated with SignalSeal, which was directly applied to the open-faced die, have been subjected to 1,000 hours of accelerated stress testing at 85°C and 85% RH as well as over 500 hours of continuous salt-fog exposure per ASTM B117. Each instance demonstrated that the device was still operation and showed no signs of corrosion after exposure. SignalSeal has also passed electronics industry standards for environmental protection in harsh environments, including the military MIL-I-46058C specification and IPC-CC-830.