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TAP TIMES                                                      Volume 11, Number 4

                                                                                          April 2020
           Test, Assembly & Packaging TIMES

           Assembly and packaging for extreme environments

                           icrowave and RF micro-               is the industry’s investment and advance-
                           circuit assembly, pack-              ments in miniaturizing smartphones,
                           aging and test require               drones, small satellites, phased-array
                           attention to detail for              technology, 5G and the Internet of Things
                           reliable operation in ex-            (IoT).
         Mtreme military and aero-
         space environments.
                                                                Unique processes
                                                                RF and Microwave hybrids are complex as-
            Tom Terlizzi, Contributing Editor                   semblies (figure at left) and require many
                                                                unique processes.

                                                                Typical processes are shown in the table
                                                                below. The need for extreme quality con-
                                                                trol has evolved over the years from
                                                                unique customer requirements to stan-
                                                                dardized control meeting MIL-PRF-38534.

                                                                           TYPICAL RF AND MICROWAVE
                                           Chip-and-wire                        HYBRID PROCESSES    1
                                         assembly standard
                                              product            • Gold Wire Bonding (ball and wedge)
                                               Agile             • Aluminum wedge bonding
                                       Microwave Technology      • Ribbon Bonding (gold 3 mils x 0.5 mils thick)
                                                                 • Surface mounting of components using screen-
        Critical issues                                             printed solder paste.
        Design issues, component sourcing, sub-                  • RF Connector Installation (solder or mechanical)
        strate selection, process selections and                 • Hermetic sealing using seam welding of Kovar
        material trade-offs are critical due to their            • Hermetic sealing using Laser welding of alumi-
        high frequency characteristics.                            num package
                                                                 • Hermetic sealing using Gold-Tin soldering
        In addition, new semiconductor device                              of Kovar package
        technology, transitioning from commer-                   • Hand Soldering
                                                                 • Eutectic Die Attach (gold tin or solder)
        cial markets (COTS) such as gallium                      • Epoxy Sealing of microwave packages
        arsenide(GaAs); gallium nitride (GaN) on                 • Epoxy die and component attach
        silicon/silicon carbide substrates; silicon              • Coil Tacking or Winding via wire bonding, weld-
        germanium (SiGe) and indium phosphide                       ing or soldering
        (InP) are now available for high reliability             • Board Installation (epoxy, solder, mechanical)
                                                                 • Beam-lead diode attachment
        applications.                                            • RF Tuning
                                                                 • RF/Microwave electrical testing and calibration
        Also driving RF and microwave technology                    of “golden units”                            next page
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