Guidebook on the Use of PEMs at High Altitudes and in Space

Objectives

Background

Approach

Objectives

To produce a guidebook for the use of PEMs in high altitude environments, especially ones including exposure to rapid altitude cycling.

Background

There are a number of reliability concerns regarding the use of plastic encapsulated microcircuits (PEMs) in high altitude strategic applications. These concerns are due to the hygroscopic nature of the plastic encapsulant and its variation between batches and manufacturers. Of particular concern is the long term reliability of PEMs in situations involving rapid changes in altitude, where the partial vacuum at high altitudes could cause moisture and ionics to be drawn into the package upon return to the high pressure, humid environments on the ground. This effort will produce a guidebook that will provide a method for assessing the reliability of PEMs in high altitude applications, especially those involving exposure to rapid altitude cycling.

Approach

The guidebook will contain the following:

• Basics of Using Commercial PEMs
• Failure Mechanisms in PEMs
• Effects of High Altitude
• Outgassing
• Temperature Cycling
• Pressure Cycling
• Speed of the Altitude Changes
• Radiation
• Pressure
• Methods to Mitigate Effects
• Shielding
• Materials Selection
• Second Level Packaging
• Microenvironment Creation
• Accelerated Qualification and Screening Tests for Parts Selection