Volatiles Control in Hermetic Electronic Components

Volatiles Control in Hermetic Electronic Components

Instructors:

Thomas Green, TJ Green Associates, LLC,

Robert Lowry, Electronics Materials Consultant

COURSE SUMMARY

This tutorial includes a basic review of the Mil Spec test methods in place to prevent moisture related failures in hermetically sealed microelectronics where functional reliability is of utmost importance (e.g. IC’s, Hybrids and RF MMIC modules, MEMs/Sensors, Class III Medical Implants, etc.). It is intended to enlighten the student on the negative, and sometimes catastrophic consequences of too much moisture or other harmful gasses inside a hermetic enclosure. The class begins with a definition of hermeticity and a description of the latest hermeticity test methods in MIL-STD-883 TM 1014, including the standard helium-based methods, plus the new Condition A5 along with Optical Leak Test (OLT) techniques, Kr-85 and other methods. The latest developments in TM 1018 IGA (Internal Gas Analysis) and revised criteria will be discussed.

Topics include:

• Moisture Failure Modes and Mechanisms
• Hermeticity and Leak Testing methods and techniques
• Moisture Control and Moisture Analysis via IGA
• War stores and Case Study examples

The hermeticity session begins with a quick review of what it means when a package is deemed to be “hermetic” vs. a “non-hermetic” package and the associated technical theory that governs each. The primary hermetic seal manufacturing processes (e.g. seam seal, laser weld etc.) is briefly discussed and then each of the major leak test methods is reviewed, compared and contrasted, including gross leak test methods. The emphasis is on practical issues the engineer faces and examples using a simple XLS spreadsheet brings to life the Howl and Mann equation.

A critical review of past RGA failures is intended to highlight the FA protocols, causes and corrective actions, and from this guide engineers new to this field, or those dealing with a current related problem, to understand internal water vapor measurements, interpret data, and avoid similar mistakes. Emphasis is placed on the methodology used to understand the underlying physics and chemistry that caused failures and appropriate design and mitigation strategies required to prevent future failures.