Fugitive Pastes
Summary
C12 Fugitive Carbon pastes for fabricating buried cavities, microchannels, and MEM's structures in Low Temperature Co-fired Ceramic (LTCC) multilayer devices and other laminated components.
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Description
C12 Carbon Paste products are made with specially processed, ultra-pure carbon. C12 thermally fugitive Carbon Pastes are used to form embedded channels, cavities, and MEMs structures in multilayer ceramics such as LTCC and HTCC substrates. C12 Carbon Pastes have the highest solids loading available, which results in very low shrinkage and crack-free prints. Other thermally fugitive pastes and materials with lower carbon loading and excessive binder content often cause stress, warping, and damage to delicate structures during firing. C12 Carbon Pastes are designed to be compatible with all major commercial LTCC tape and screen printable systems.
Ultra-pure C12 Carbon Pastes are engineered to burn out cleanly in air atmospheres. C12 Carbon Pastes begin to rapidly oxidize at 600C, just as the LTCC ceramic matrix sinters, leaving behind well-defined features such as cavities and channels. C12 Carbon Pastes create precise, stress-free structures, unlike conventional fugitive materials such as waxes and polymers, which often leave residue and result in stress related deformation. C12 Carbon Pastes can also be a cost effective alternative to using removable inserts such as platinum or latex for creating structural features.
The Advantages of C12 Carbon Paste
♦ Forms in-situ channels and buried cavities in LTCC multilayers and other laminated components.♦ Prevents deformation during high pressure lamination of multilayer structures.♦ Prevents slumping during firing.♦ Contains high purity carbon which burns out cleanly in air atmospheres – sublimates directly without causing stress on green parts.♦ Cost effective substitute for removable inserts (e.g. latex, platinum, etc.)♦ Does not require complex lamination and firing cycles that are necessary when using other fugitive materials such as wax or polymeric materials.♦ Compatible with all major commercial LTCC tape and screen printable systems.
Applications
Applications include forming buried channels, cavities and ports in:
♦ Low Temperature Co-fired Ceramics (LTCC).♦ Solid Oxide Fuel Cell (SOFC) membranes.♦ Ceramic MEM's.♦ Microfluidic devices with channels for gasses and fluids.♦ Suspended structures, (accelerometers, pumps, flow sensors, air core inductors, etc.)♦ Microreactors and microcombustors.♦ Laminated Object Manufacturing (LOM) and rapid prototyping.♦ Thermally fugitive masking materials.
♦ Low Temperature Co-fired Ceramics (LTCC).♦ Solid Oxide Fuel Cell (SOFC) membranes.♦ Ceramic MEM's.♦ Microfluidic devices with channels for gasses and fluids.♦ Suspended structures, (accelerometers, pumps, flow sensors, air core inductors, etc.)♦ Microreactors and microcombustors.♦ Laminated Object Manufacturing (LOM) and rapid prototyping.♦ Thermally fugitive masking materials.
C12 Carbon Pastes begin rapid burn-out (oxidation) in air just before pore closure begins in LTCC ceramic (DP951 Green Tape).
Recommended firing schedule for creating defect-free microchannels and buried cavities in LTCC multilayers.
Design for a “thermally isolated” micro-hotplate in a ceramic (LTCC) substrate. Suspended bridge structure is printed on top of cavity filled with thermally fugitive C12 Carbon Paste.
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Cross section showing buried micro-channels formed in LTCC laminates with thermally fugitive C12 Carbon paste (approx. 40um).
(a) Front of mesovalve manifold with standard connectors. (b) Back of manifold showing contoured channels formed by LTCC Carbon Paste lamination as described by K. Peterson, et al., in Ref. 2. (Photo reproduced with permission of International Microelectronics And Packaging Society, Washington DC, CICMT 2005).
Air core inductors fabricated using LTCC Carbon Paste with LTCC tape and screen printed conductors as described by K. Peterson, et al., in Ref. 2. (Photo reproduced with permission of International Microelectronics And Packaging Society, Washington DC, CICMT 2005).