HMC-ABH209 v03.0714 Gaas HEMT MMIC MEDIUM POWERAMPLIFIER, 55 - 65 GHzMounting & Bonding Techniques for Millimeterwave GaAs MMICs The die should be attached directly to the ground plane eutectical y or with 0.102mm (0.004”) Thick GaAs MMIC conductive epoxy (see HMC general Handling, Mounting, Bonding Note). 50 Ohm Microstrip transmission lines on 0.127mm (5 mil) thick alumina Wire Bond IP thin film substrates are recommended for bringing RF to and from the chip 0.076mm (0.003”) H (Figure 1). If 0.254mm (10 mil) thick alumina thin film substrates must be used, the die should be raised 0.150mm (6 mils) so that the surface of the die is coplanar with the surface of the substrate. One way to accom- plish this is to attach the 0.102mm (4 mil) thick die to a 0.150mm (6 mil) RF Ground Plane R - C thick molybdenum heat spreader (moly-tab) which is then attached to the IE ground plane (Figure 2). Microstrip substrates should be placed as close to the die as possible in 0.127mm (0.005”) Thick Alumina LIF order to minimize bond wire length. Typical die-to-substrate spacing is Thin Film Substrate P 0.076mm to 0.152 mm (3 to 6 mils). Figure 1. M Handling Precautions Follow these precautions to avoid permanent damage. 0.102mm (0.004”) Thick GaAs MMIC R A Storage: All bare die are placed in either Waffle or Gel based ESD pro- E Wire Bond tective containers, and then sealed in an ESD protective bag for shipment. 0.076mm (0.003”) W Once the sealed ESD protective bag has been opened, all die should be O stored in a dry nitrogen environment. Cleanliness: Handle the chips in a clean environment. DO NOT attempt to clean the chip using liquid cleaning systems. RF Ground Plane Static Sensitivity: Fol ow ESD precautions to protect against ESD R & P strikes. 0.150mm (0.005”) Thick A Moly Tab Transients: Suppress instrument and bias supply transients while bias is 0.254mm (0.010”) Thick Alumina E applied. Use shielded signal and bias cables to minimize inductive pick-up. Thin Film Substrate Figure 2. General Handling: Handle the chip along the edges with a vacuum col et LIN or with a sharp pair of bent tweezers. The surface of the chip may have fragile air bridges and should not be touched with vacuum col et, tweezers, or fingers. Mounting The chip is back-metal ized and can be die mounted with AuSn eutectic preforms or with electrical y conductive epoxy. The mounting surface should be clean and flat. Eutectic Die Attach: A 80/20 gold tin preform is recommended with a work surface temperature of 255 °C and a tool temperature of 265 °C. When hot 90/10 nitrogen/hydrogen gas is applied, tool tip temperature should be 290 °C. DO NOT expose the chip to a temperature greater than 320 °C for more than 20 seconds. No more than 3 seconds of scrubbing should be required for attachment. Epoxy Die Attach: Apply a minimum amount of epoxy to the mounting surface so that a thin epoxy fil et is observed around the perimeter of the chip once it is placed into position. Cure epoxy per the manufacturer’s schedule. Wire Bonding RF bonds made with 0.003” x 0.0005” ribbon are recommended. These bonds should be thermosonical y bonded with a force of 40-60 grams. DC bonds of 0.001” (0.025 mm) diameter, thermosonical y bonded, are recommended. Ball bonds should be made with a force of 40-50 grams and wedge bonds at 18-22 grams. All bonds should be made with a nominal stage temperature of 150 °C. A minimum amount of ultrasonic energy should be applied to achieve reliable bonds. All bonds should be as short as possible, less than 12 mils (0.31 mm). Inf F or o m r p atio r n ifc ur e n , d ishe e d lbiv y e A r n y a alog n D d t evic o p es is la beclie o eved rd to ebre sa: H ccur iattti e tae M nd re ilicarbloew . H a o ve C wever, o n rp o For price, delivery, and to place orders: Analog Devices, Inc., responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other oration, 2 Elizabeth Drive, Chelmsford, MA 01824 One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106 Phone: 978-250-3343 Fax: 978-250-3373 O rights of third parties that may result from its use. Specifications subject to change without notice. No P rd hone e r O : 7 n 81- -3li 2n 9 e a -47 t w 0 w 0 • O w rd .h e it r o t niltie n .c e ao t m license is granted by implication or otherwise under any patent or patent rights of Analog Devices. www.analog.com 6 Application Support: Pho Trademarks and registered trademarks are the property of their respective owners. ne: 978-250-33 A 4 p 3 p o lica rti a o p n S p u s p @ po h rt itt : P ite ho . n c e om : 1-800-ANALOG-D
