Void Free Curing with Pressure
Today’s increasing durability and reliability standards are making void free curing a necessity.
Issues Caused by Voids
- Reduced adhesion of device to substrate
- Reduced thermal performance
- Electrical failures from “solder creep”
- Lower reliability & shorter lifetime
Pressure Curing Removes Voids
As pressure is increased, more gas molecules are able to dissolve (Henry’s Law)
- Henry’s Law – The amount of dissolved gas in a liquid is proportional to its partial pressure above the liquid.
- Increasing pressure during the curing process removes voids.
Bubbles in UF dissolve as pressure is increased.
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Residual gas bubbles in the curing medium are dissolved as pressure increases.
Dissolved Gas Spreads Out Through Diffusion.
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The dissolved gas spreads throughout medium by diffusion. When it reaches the edge it escapes through outgassing.
Dissolved gas escapes at the edges through outgassing.
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Eventually all residual gas is removed, leaving the curing medium void free.
Pressure Curing Oven Process
- A Pressure Cure Oven (PCO), or Autoclave, is used to minimize voiding and increase adhesion strength for a variety of bonding and curing application.
- A PCO pressurizes a rigid chamber with air or Nitrogen and maintains a pressure profile during the curing cycle as defined by the recipe.
- Convection heaters and heat exchangers maintain a recipe-defined thermal profile during the entire curing cycle.
A typical PCO temperature and Pressure profile.
Typical PCO Applications
- Die Attach Curing
- Underfill Curing
- Ag Sintering Cure
- MEMS Sealing
- Taping / Lamination
- PCB Via Fill
- Encapsulation Curing
- Composite Forming
Click here to learn more about our pressure curing ovens