Measuring mass flows in hermetically sealed MEMs MOEMs to ensure device reliability

摘要

Many MEMs and MOEMs devices require controlled ambient environments for successful operation. Controlled ambients are usually obtained via hermetic packaging. These controlled environments must first be obtained and then maintained to prevent their degradation over the device lifetime. Controlled ambients decay in quality over time due to various mechanisms including leaks, permeation, poor processing and outgassing of species like hydrogen, water and organics external and internal to the package. The key to controlling the process of degradation is to understand in a quantitative manner which species are present and their mass flow rates into the controlled ambient. The current work describes a new technique for determining these species and mass flow rates. This new technology provides tremendous sensitivity to package volumes < 0.01cc compared to standard quadrupole techniques, which are applicable to samples larger than 0.01 cc. The technology is based on a high speed, high mass resolution, and highly sensitive Time-Of-Flight (TOF) spectrometer to test the tiniest of devices with significant advancement in signal-to-noise ratios. Key operational parameters demonstrated include: 1. Spectra Acquisition speed: 1 full spectra every 20 μs. 2. Mass Range: mass 2 to 150 standard (2-500 capable) 3. Mass resolution: 0.1 AMU 4. Calibration Fixtures: 0.0001,0.0005,0.001,0.005 and 0.01 cc 5. Sample temperature: 100°C standard (room temperature to 150°C capable)