Electronic Packaging Materials - Page 2 of 3
Benefits Of Silicone As Electronic Packaging Material
- Low Moisture Absorption, <0.4%
- Dielectric Strength, > 500V/mil (0.001 inch) or 20 kV/mm
- Thermal Stability, -115 °C to 260 °C
- Low Modulus
- Low Shrinkage, <1%
- Low Ionic Content (Na, K, Cl and NH3)
- Low Outgassing, <1% at 1 hr @ 275°C
- Available as gels, elastomers and greases
Contamination
Silicone adhesives have had a reputation over the years of "contaminating" surrounding areas with silicone oils while the device is in operation. NuSil Technology has addressed this by designing products in our EPM product line to introduce minimal contamination by the following criteria:
- Contain low concentrations of silicone oils: < 1 % Weight Loss when heated 1 hour at 275 °C.
- Low Ion Content: < 20 ppm of individual Na, K and Cl ions per MILSTD 883E.
- Addition Cure Mechanism: This cure mechanism has minimal shrinkage and does not produce chemical by-products, such as acids or alcohols that can affect components in assemblies.
Silicone "oils" are low molecular weight silicones generated during the production of silicone polymers. The polymerization reaction often begins with polyorganosiloxane rings(A.K.A.cyclics) reacting with short chain siloxane species that act as chain terminators in the presence of an acid or base catalyst. The reaction is thermodynamically controlled and the concentration of the various chemical species produced is allowed to reach equilibrium over time. The chemical species produced during this reaction are a range of molecular weights of linear and cyclic compounds. Heat and vacuum are applied and the low molecular weight species can be removed. NuSil Technology has been performing this technique, known as "Wiped Film Evaporation" for the Aerospace industry for 30 years and are experts in this technology.Next Page->
