Dispensable cured resin
View Patent ↗The present invention discloses methods, materials and devices for facilitating electromagnetic/radiofrequency interference (EMI/RFI) shielding and thermal management in packaging circuits. More specifically, a method of packaging integrated circuits with improved thermal and EMI management, a process of treating a compound for use as a thermal interface and/or an EMI shield, and an EMI shielding and thermal management apparatus. More specifically, the present invention divulges methods and apparatuses for adjusting viscosity of a thermally and/or electrically conductive (or thermally conductive and/or electrically insulative), form-in-place, fully cured compound thereby rendering the compound dispensable. Further, a process of treating a compound for use as a thermal interface or/and an EMI shield is disclosed. The compound is an admixture of a particulate filler component and a pre-cured gel component. The process includes applying a shearing force on the compound, thereby rendering the compound dispensable.
1. A process of using an elastomeric compound as a thermal interface and an EMI shield, the process consisting essentially of:
applying a shearing force to the compound thereby reducing the viscosity of the compound to render the compound dispensable, said compound comprising a cured polymer gel component and an admixture of a particulate thermally and electrically conductive filler component, said particulate filler component having an average particle size of between about 0.01-10 mils present in an amount of from about 20-80% by total weight of the compound,
wherein the compound is dispensed into a gap of between about 0.25 mm and about 3.00 mm intermediate a surface of a first electronic component and a second electronic component, said compound being fluent under the shearing force exerted when dispensing said compound, and form-stable in the dispenser and the gap, and wherein the cured gel component in the compound as dispensed does not exhibit further appreciable curing.
2. The process of claim 1 , wherein the filler component has a thermal conductivity of at least about 20 W/m-K.
3. The process of claim 1 , wherein the filler component is selected from the group consisting of oxide, nitride, carbide, diboride, graphite, and metal particles, and mixtures thereof.
4. The process of claim 1 , wherein the compound has a thermal conductivity of at least about 0.5 W/m-k.
5. The process of claim 1 , wherein the compound has a viscosity of about 7.5 million cps in the dispenser, and a viscosity of about 1.5 million cps upon shearing.
6. The process of claim 1 , wherein the compound has an inherent operating temperature ranging from a minimum of approximately −50° C. to a maximum of roughly 150° C.
7. The process of claim 1 , wherein the compound has an inherent specific gravity of 2.25.
8. The process of claim 1 , wherein the compound exhibits a weight loss of approximately 0.2% in 24 hours at 150° C. upon performance of a thermogravimetric analysis (TGA) after preparation of the compound.
9. The process of claim 1 , wherein the compound has a flow rate of approximately 10 cc/min when dispensed.
10. The process of claim 1 , wherein the compound has approximately 6% extractable silicones after preparation of the compound.
11. The process of claim 1 , wherein the compound has a dielectric strength of approximately 1000 Vac/mil @ 10 mil when dispensed in the gap.
12. The process of claim 1 , wherein the compound has a volume resistivity of approximately 1×10 14 ohm-cm when dispensed in the gap.
13. The process of claim 1 , wherein the compound has a shelf life of 18 months at room temperature in the dispenser.
14. The process of claim 1 , wherein the compound exhibits an EMI shielding effectiveness of at least about 60 dB over a frequency range of between about 10 MHz and about 10 GHz when dispensed in the gap.
15. The process of claim 1 , wherein the polymer gel component comprises a silicone polymer.