Dennis, I had a quick look at your companies web site. I take it that hermetic sealing is something that you want to get into to extend your product range. I used to be involved with this in a previous job. We used two basic technologies, high temperature solder, or a glass frit. The solder was 80/20 gold tin eutectic. This melts at around 320C. We used these on ceramic packages and kovar lids. The sealing areas on the packages and lids are metallised with 60 micro inches minimum of gold as the top layer. The solder was applied as a preform tacked to the lid by the lid manufacturer. The lid was placed on the package with a clip and passed through an N2 atmosphere belt furnace to seal. The use of all gold surfaces meant that no flux was needed. The other method used a glass frit on ceramic lids. These melted in a 440C air atmosphere belt furnace to seal to ceramic packages. These required no nitrogen inerting and no extra metallisation, but at the cost of increased temperature exposure. This technology will have moved on since and lower temperatures are probably possible. Testing for hermiticity is also required. We based our tests on Mil std 883. There may be ANSI replacements for these. Take a look at the EIA/JEDEC web site at http://www.jedec.org.Two tests are used, gross leak to find big holes and fine leak for small. A number of different methods are used. For gross leak we immersed parts in a fluorocarbon under pressure, then placed them in a heated bath of another fluorocarbon of higher boiling point. Any fluorocarbon in the package would evaporate and bubble out. For small holes we placed parts in a pressurised helium chamber, then into a helium detector. Any helium inside the package would leak out and be detected. I would recommend that you talk to package and lid suppliers. Kyocera, NTK technical ceramic, Indium Corp and Williams spring to mind. They probably all have web sites as a first point of contact. regards, Jeremy Drake Celestica Ltd Kidsgrove Stoke on Trent England. ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################