Datasheet HMC498 (Analog Devices) - 6

HMC498
v03.0713
GaAs pHEMT MMIC POWER AMPLIFIER, 17 - 24 GHz Mounting & 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 H (0.003”) (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) S - C RF Ground Plane thick molybdenum heat spreader (moly-tab) which is then attached to the R ground plane (Figure 2). IE Microstrip substrates should brought as close to the die as possible in 0.127mm (0.005”) Thick Alumina order to minimize bond wire length. Typical die-to-substrate spacing is Thin Film Substrate LIF 0.076mm to 0.152 mm (3 to 6 mils). Figure 1. P
Handling Precautions
M Follow these precautions to avoid permanent damage. 0.102mm (0.004”) Thick GaAs MMIC
Storage:
All bare die are placed in either Waffle or Gel based ESD pro- R A tective containers, and then sealed in an ESD protective bag for shipment. Wire Bond E 0.076mm Once the sealed ESD protective bag has been opened, all die should be (0.003”) W stored in a dry nitrogen environment. O
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 strikes.
Transients:
Suppress instrument and bias supply transients while bias is 0.150mm (0.005”) Thick R & P Moly Tab applied. Use shielded signal and bias cables to minimize inductive pick-up. A 0.254mm (0.010”) Thick Alumina E
General Handling:
Handle the chip along the edges with a vacuum col et Thin Film Substrate or with a sharp pair of bent tweezers. The surface of the chip may have Figure 2. IN fragile air bridges and should not be touched with vacuum col et, tweezers, or fingers. L
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
Ball or wedge bond with 0.025mm (1 mil) diameter pure gold wire. Thermosonic wirebonding with a nominal stage temperature of 150 °C and a ball bonding force of 40 to 50 grams or wedge bonding force of 18 to 22 grams is rec- ommended. Use the minimum level of ultrasonic energy to achieve reliable wirebonds. Wirebonds should be started on the chip and terminated on the package or substrate. Al bonds should be as short as possible <0.31mm (12 mils). 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
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