Hermeticity Verification
Standardized testing procedures that evaluate the integrity of hermetic seals on microelectronic packages ensure the long-term reliability of sensitive components in harsh environments. The mil-std-883 method 1014 defines the specific test methods and limits for detecting both fine and gross leaks in semiconductor packages. It provides a detailed framework for applying helium mass spectrometry or radioactive tracer techniques to verify that moisture or other contaminants cannot penetrate the package seal.
Testing Phase
The procedure typically involves a pressurized bombing phase where the device under test is exposed to a tracer gas for a specified duration. If a leak is present, the gas will penetrate the package. The device is then transferred to a vacuum chamber connected to a mass spectrometer to measure the rate at which the tracer gas escapes from the package.
This leakage rate is compared against the maximum permissible limits defined in the standard.
Metrological Calibration
Accurate leak detection requires the calibration of the mass spectrometer using standard reference leaks of known flow rates. These reference leaks must be calibrated against standards maintained by national metrology institutes. If the reference leak rate is incorrect, the system may fail to detect devices with marginal leak rates, which could lead to field failures in high-reliability applications.
Operational Boundary
The standard defines distinct test methods for fine and gross leaks because a large leak will allow the tracer gas to escape before the device is placed in the mass spectrometer chamber. If a device has a gross leak, the gas escapes so quickly that the fine leak test will report a false pass, making it necessary to perform a separate gross leak test, such as a bubble test or optical leak detection. This sequential testing is necessary to ensure that both types of leaks are detected.
