Hermeticity of microelectronic packages and hermeticity test techniques continue to be critical reliability concerns. Specifically, in the area of microcircuits, hybrids, microwave modules, MEMS, optoelectronic devices, Class III Medical devices, sensors and other types of packaged components for the military, medical and aerospace industry. Hermeticity is an important reliability consideration, but also a significant cost driver. There have been many recent advancements in non-hermetic packaging, and given the potential for tighter hermeticity spec limits in TM 1014, and the associated costs of hermetic packaging, more OEMs are now looking at “non-hermetic” packaging alternatives. This webinar looks at some of the critical technical aspects of both technologies.
There are a variety of ways to create a hermetic seal and each of the major processes will be briefly described. The basic theory of moisture ingress and rationale for the military RGA 5000 PPM specification will be described. We then examine the conventional hermeticity fine and gross leak test techniques as prescribed in MIL-STD-883 Test Method 1014. This misunderstood test method is often a source of frustration and confusion. We’ll discuss the theory behind the test method and point out some of the common pitfalls.
Optical Leak Test (OLT) is a method that makes use of a laser interferometer to measure out plane deflection on a lid surface in response to a changing pressure and relates these measurements to an equivalent helium leak rate. Cumulative Helium Leak Detection (CHLD) is a hermeticity test technique that can measure leak rates as low as 10E-13 He cc/sec. Both methods allow for both gross and fine leak detection in a single test cycle and without the use of a liquid. The radioisotope Kr-85 method is widely used especially for small cavity, high volume packaged parts. The latest developments in helium mass spectroscopy (HMS) will also be described including the new TM 1014 condition A5.
For years the community has lived with a 1E-06 air leak rate for the larger volume hybrid style packages as specified in TM 1014. Recently some specs have changed and adopted a two order of magnitude decrease in the allowable air equivalent leak rate. This presentation will examine the ramifications of a tighter leak spec.
Packages made from polymeric materials, (e.g. LCP or Teflon) as opposed to traditional hermetic seals (e.g. metal, ceramic etc) require a different approach from a hermeticity testing standpoint. The problem is now one of moisture diffusion through the barrier and package interfaces, which is different that water vapor permeating a crack in a glass to metal interface. This will require new test methods and new procedures for component qualification.
Course attendees are encouraged to download and read a white paper titled “Hermetic vs. ‘Near Hermetic’ Packaging – a Technical Review
Mr. Thomas Green is the principal at TJ Green Associates LLC (www.tjgreenllc.com) a Veteran Owned Small Business focused on training and consulting for military, space and medical microelectronic devices. He has thirty five years of experience in the field of microelectronics packaging and has worked at Lockheed Martin Astro Space and USAF Rome Laboratories. At Lockheed he was a Staff engineer responsible for the materials and manufacturing processes used in building custom high reliability space qualified microcircuits for military and commercial communication satellites. Tom has demonstrated expertise in seam sealing and leak testing processes. He has conducted experiments and presented technical papers at NIST (National Institute Standards and Technology) and IMAPS on leak testing techniques and optimization of seam welding processes through statistical DOE methods. He has experience with OLT (Optical Leak Technology) and CHLD (Cumulative Helium Leak Detection). Tom has a B.S. in Materials Engineering for Lehigh University and a Masters from the University of Utah.