Reliability for Air Cavity Electronic Packaging Hinged on Lid-Sealing Adhesive Under Controlled Isothermal Sealing Process with Inert Backfilled Air

Cavity Electronic Packaging Reliability for Near-Hermetic Packaged Devices Depends both on Lid-Sealing Materials and Lid-Bonding Processing: 

Carefully designed and engineered batch or inline isothermal lid-sealing control with backfilling N2 during the lid-bonding process is critical for pin-hole-free and reliable lid-sealing. The lid-sealed electronic package with fully back-filled N2 or equivalent inert air is at least as important as the high moisture and corrosive gases barrier lid-sealing adhesive. The lid-sealing adhesive ideally should facilitate and provide flexibility in the iso-thermal and pressurized lid-sealing process. The following are some of the lid-sealing material solutions to optimize the cavity electronic packaging reliability: 

  1. High moisture barrier molded LCP plastic cavity and lid are important but must also pair with matching moisture barrier lid-sealing adhesive sealant for best long-term reliability. 
  2. Die-Attach film and paste adhesives free of ionic impurities and low moisture absorption accompanied with high moisture barrier conformal coating on exposed circuit traces also added to the reliability.
  3. High bond strength and high-temperature moisture barrier lid-sealing adhesive sealant besides keeping the moisture out and backfilled inert N2 inside the cavity packaging.

True Near-Hermetic Lid-Seal Solutions with Designed Work-Flow Friendly Molecular Structure Ideally Suited for High Volume Inline Cavity Electronic Packaging Production: 

What distinguishes AIT’s FLUROSEAL® cavity electronic packaging lid-seal adhesive in comparison to the traditional epoxy lid-seal adhesive besides its molecular structure designed to block moisture and corrosive gases from penetration is its production workflow cycle friendly for batch and inline production.    

  • Dispensable and B-stageable FLUROSEAL® lid-seal adhesives have a long floor life of more than 5 days. 
  • Easy B-staging at below 60°C to form dry to touch solid adhesive on LCP, metallic, ceramic, or glass lids for ease of handling and pick-and-place lid-placement during production.
  • Once B-staged, the lid-seal adhesive is dry and ambient storable for 12 months for ease of shipping and usage. 
  • Instead of maintaining constant pressure on the lid during the curing cycle for the batch production with the use of traditional B-staged epoxy adhesive, B-staged FLUROSEAL® lid-seal adhesive on lid cover has high “heat melt green strength” to allow releasing placement fixture after initial cycle lid-placement within the isothermal nitrogen backfilled chamber environment. Example of inline workflow for high volume cavity lid-sealing production:
    1. Preheat the cavity packages without lids in an array fixture plate to 150°C.
    2. Move the heated fixture plate with cavity packages into a nitrogen backfilled and controlled chamber.
    3. Pick-and-place lids with B-staged adhesive onto each package with adequate placement pressure of > 5psi to induce adequate adhesive flow. 
    4. Remove the array of cavity packages with lid-seal for completion of curing at 150°C hot stage.