Develop Attachment Process for Ion Grids to Low Temperature Co-Fired Ceramic (LTCC)
The Ceramic- Microelectromechanical Systems (C-MEMS) Laboratory at BSU is developing miniature electrostatic thrusters for small-scale satellites in orbit using Low Temperature Co-Fired Ceramics (LTCC). Electric thrusters are preferable to chemical thrusters for satellite applications due to their extremely high efficiency. The LTCC system provides unique design and performance characteristics in an ion thruster platform. Specifically important is the grid attachment and its innate resistance as a stable focusing platform for the ion flow used to optimize the ion thrust parameters. The ion grids being developed for this project will focus and accelerate the ions to produce thrust. The cylindrical plasma containment tubes fabricated from rolled LTCC have an internal body diameter of 21.8mm and a step inner diameter of 23.3mm in which ion grids will be retained. Confined between the layers of the tube is DuPont 6145 silver paste that allows the grid to be electrically connected to an inductively coupled plasma antenna base which is fabricated in LTCC as well. This presentation focuses on the containment tube and how it will be integrated to work with the ion grid development process that is used as the ion exhaust port. In this experiment, the grid structure is attached to a ceramic base which simulates the LTCC ceramic containment tube that will be used in production. The upper chamber on the interior of the cylinder has an I.D. of 23.3mm; at the union between this, and the 21.8mm I.D. lower chamber of the cylinder is a 1.5mm ridge where silver paste is added to electrically bond the embedded lower grid through internal silver traces to the upper main grid platform in an effort to match resistance and conductivity between the two platforms. The grids are physically attached to the assembly in a planar process using epoxy and/or solder. Destructive tests will determine the shear force required to detach the grid assembly from the main platform. The initial design parameters will be described and the prototype lab development work will be presented. Finally, preliminary data will be presented with regard to grid attachment techniques and overall grid resistance in relation to the ion thrust platform.