Hermetic packages

When sourcing hermetic packages, you must prioritize material compatibility and sealing integrity. Key specifications include the Leak Rate, which should typically meet MIL-STD-883 (Method 1014) standards (often < 1x10^-8 atm·cc/s helium). You should also evaluate the Coefficient of Thermal Expansion (CTE) matching between the housing (e.g., Kovar, AlSiC, or Ceramics) and the glass or ceramic seals to prevent cracking during thermal cycling. For high-power applications, ensure the Thermal Conductivity of the base material is sufficient to dissipate heat effectively.

For aerospace and defense, suppliers must adhere to MIL-PRF-38534 or MIL-PRF-38535 certifications. If the packages are intended for medical implants, compliance with ISO 13485 and biocompatibility standards is essential. Additionally, ensure all components are RoHS and REACH compliant to avoid hazardous substances like lead, unless specific exemptions apply for high-reliability military use.

Plating is critical for corrosion resistance and solderability. Common options include Electroless Nickel Immersion Gold (ENIG) or Electrolytic Gold over Nickel. A minimum gold thickness (typically 50 micro-inches for wire bonding) is required to ensure reliable connections. You should verify that the plating process prevents gold embrittlement in solder joints and provides a robust barrier against oxidation in harsh environments.

Glass-to-Metal Seals (GTMS) are ideal for sensors and power feedthroughs due to their high pressure resistance. Ceramic-to-Metal Seals are preferred for high-frequency (RF) and high-voltage applications because of their superior dielectric properties. For microelectronics, Parallel Seam Welding or Laser Welding of the lid is the industry standard to maintain a controlled internal atmosphere (usually 90% Nitrogen / 10% Helium).

Always request a Certificate of Conformance (CoC) and Full Traceability Reports back to the raw material melt. For high-stakes orders, mandate Third-Party Inspection (such as scanning electron microscopy or X-ray fluorescence) before the balance payment is made. Sourcing through verified premium suppliers on Made-in-China.com can reduce risk, as these manufacturers often undergo rigorous factory audits.

Hermetic packaging often involves long lead times due to custom tooling and specialized plating cycles. Negotiate a Blanket Purchase Order where the supplier holds raw material inventory in exchange for a guaranteed annual volume. This can reduce lead times from 12 weeks to 4 weeks for call-off orders. For custom designs, aim for an NRE (Non-Recurring Engineering) fee waiver if the initial order exceeds a specific value.

Hermetic packages are sensitive to electrostatic discharge (ESD) and mechanical shock. Ensure the supplier uses ESD-safe vacuum packaging and cushioned inner boxes. For international sea or air freight, specify the use of desiccants and humidity indicator cards within the moisture barrier bags to prevent oxidation of the leads during transit.

Be aware that high-end hermetic packages may fall under Dual-Use Goods regulations or ITAR/EAR restrictions depending on their technical capabilities (e.g., high-frequency limits). Confirm with the supplier if an Export License is required from the country of origin. Ensure all HS Codes (typically 8547.90 or 8538.90) are correctly declared to avoid customs delays or unexpected anti-dumping duties.