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348 MEMS and Microstructures in Aerospace Applications

16.6 Final Integration ........................................................................................ 365
16.7 Conclusion ................................................................................................. 366
References............................................................................................................. 366

16.1 INTRODUCTION

The objective of this chapter is to supplement the strong infrastructure in space
mission quality assurance with information for microelectromechanical systems
(MEMS) and microstructure-related space activity. The generic elements of any
good quality assurance plan apply to the use of microtechnologies in critical and
noncritical space flight applications. The quality assurance plan should be carried
out during the formulation phase of the project. Generic categories of the quality
assurance program include but are not limited to:
. Quality planning
. Design and development
. Change control
. Contractor surveillance
. Procurement
. Receiving, processing, fabricating, assembly, test, and inspection control
. Contamination control
. Metrology and calibration
. Handling, packaging, packing, and storage controls
. Quality records
. Quality audits
. Process improvement
. Reliability
. Safety
. Software quality
16.1.1 COMMERCIAL VS.SPACE ENVIRONMENT
The use of MEMS in space does not have the volume benefits of the commercial
world or the knowledge base seen in space-grade integrated circuits (IC). Commer-
cial production of MEMS devices is a high-volume manufacturing activity where
reliability, efficient process, product characterization, and testing are well defined
from the very earliest development phase up. Elimination of process and design-
related failure mechanisms through statistical analysis and understanding of the
physics of failure yields defect-reduction programs. Successful commercial pro-
1
grams nurture high yield and profitable, yet reliable production lines. In addition,
simulation tools, process-monitoring tools, and advanced characterization tools
are tailored to the product developed. 2–5 These tools and process monitors ensure a
reduction in the risk of processing errors, along with an integrated process or
product approach using quality systems and high-volume manufacturing. This is
critical to the production of high-quality products. Unfortunately, a key element
here is volume production, which is not common in most spacecraft applications.
None of the commercial lines in the United States (and perhaps the world) are
developed with the intent to produce space-grade MEMS, and most facilities

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