Page 267 - An Introduction to Microelectromechanical Systems Engineering

246 Packaging and Reliability Considerations for MEMS

Table 8.8 A Summary of the Key Reliability Tests Specified Under the Telcordia Standards GR-63/463 and
GR-1209/1221 for the Qualification of Devices for Optical Telecommunications
Test GR-63/463-CORE Reliability GR-1209/1221-CORE Reliability Assurance
Assurance for Optoelectronic Devices for Branched and Passive Fiber-Optic Devices
Mechanical 500G for 1 ms, 5 times/axis 500G for 1 ms, 2 times/axis; 200G for
shock 1.33 ms, 2 times/axis
Nonoperational 20G, 20–2,000 Hz, 20G, 20–2,000 Hz, 4 min/cycle, 4 cycles
vibration 4 min/cycle, 4 cycles
Operational 5.0G, 10–100 Hz; 2.4G, 10–55 Hz, 1.52 mm amplitude, 20 min
vibration 100–200 Hz per 3 axes
Thermal shock 15 cycles, 0° to 100°C —
(air-to-air)
Solderability +260°C for 10s —
Accelerated aging 70°C or 85°C, > 2,000 hours —
(operational)
High-temperature +85°C, 2,000 hours +85°C, RH<40% RH, 2,000 hours
storage
Low-temperature –40°C, 2,000 hours –40°C, 2,000 hours
storage
Temperature –40°C to +70°C, >100 cycles –40°C to +70°C, >100 cycles; –40°C to
cycling +70°C, 10% to 80% RH, 42 cycles
Damp heat +85°C/85% RH, 1,000 hours +85°C/85% RH, 500 hours
Internal moisture <5,000 ppm water vapor —
ESD threshold ±500-V discharge, each pin set —
Fiber pull 1.0 kg, 3 times, 5-s duration —
Fiber twist and — 0.5-kg load, 100 cycles
flex tests
Side pull — 0.25 to 0.5 kg-load at 90° angle
Cable retention — 0.5 to 1 kg-load for 1 minute
Water immersion — 43°C, pH 5.5, for 336 hours
(Source: [27].)

advised to seek such professional recourse. The user of MEMS products will often
demand that those products are certified under one or many quality standards that
are most applicable to the user’s industry. However bureaucratic these standards
may on occasion be perceived by the general scientific community, they are of para-
mount importance to the MEMS industry as it transitions from prototyping experi-
mentation to mature manufacturing.

Statistical Methods in Reliability

If one defines reliability as the probability that a device will perform its specified
functions without failing over an expected operating time within defined operating
and environmental conditions, then it becomes clear that statistics play an important
role in assessing and predicting the reliability of a product. This section introduces a
few key concepts and terms commonly used in the theory of reliability. The reader is
(
referred to the books by Bajenescu et al. [28] and Kececioglu [29, 30] for further
insight on the methodologies of reliability.
Failure is defined as the termination of the ability of a product to meet required
specifications or perform a required function. Failures are random events that are
statistically independent and can thus be described by standard probability distribu-
tion functions that follow the Poisson process. Depending on the underlying physics,