Datasheet HMC459 (Analog Devices) - 7

HMC459
v01.1007
GaAs PHEMT MMIC POWER AMPLIFIER, DC - 18 GHz Mounting & Bonding Techniques for Millimeterwave GaAs MMICs
The die should be attached directly to the ground plane eutectically or with conductive epoxy (see HMC general Handling, Mounting, Bonding Note). 0.102mm (0.004”) Thick GaAs MMIC 50 Ohm Microstrip transmission lines on 0.127mm (5 mil) thick alumina Wire Bond 3 thin fi lm substrates are recommended for bringing RF to and from the chip 0.076mm (Figure 1). If 0.254mm (10 mil) thick alumina thin fi lm substrates must be (0.003”) 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- IP plish this is to attach the 0.102mm (4 mil) thick die to a 0.150mm (6 mil) thick molybdenum heat spreader (moly-tab) which is then attached to the RF Ground Plane H ground plane (Figure 2). Microstrip substrates should brought as close to the die as possible in order to minimize bond wire length. Typical die-to-substrate spacing is 0.127mm (0.005”) Thick Alumina S - C Thin Film Substrate 0.076mm to 0.152 mm (3 to 6 mils). R Figure 1.
Handling Precautions
IE Follow these precautions to avoid permanent damage. 0.102mm (0.004”) Thick GaAs MMIC IF L
Storage:
All bare die are placed in either Waffle or Gel based ESD protec- Wire Bond P tive containers, and then sealed in an ESD protective bag for shipment. 0.076mm Once the sealed ESD protective bag has been opened, all die should be (0.003”) M stored in a dry nitrogen environment.
Cleanliness:
Handle the chips in a clean environment. DO NOT attempt R A to clean the chip using liquid cleaning systems. RF Ground Plane E
Static Sensitivity:
Follow ESD precautions to protect against ESD W strikes. 0.150mm (0.005”) Thick Moly Tab O
Transients:
Suppress instrument and bias supply transients while bias 0.254mm (0.010”) Thick Alumina is applied. Use shielded signal and bias cables to minimize inductive Thin Film Substrate pick-up. Figure 2.
General Handling:
Handle the chip along the edges with a vacuum collet or with a sharp pair of bent tweezers. The R & P surface of the chip may have fragile air bridges and should not be touched with vacuum collet, tweezers, or fi ngers. A
Mounting
E The chip is back-metallized and can be die mounted with AuSn eutectic preforms or with electrically conductive epoxy. IN The mounting surface should be clean and fl at. L 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 fi llet 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 recom- mended. 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. All bonds should be as short as possible <0.31mm (12 mils). Information furnish F ed obr pri y Anal ce, de og Device li s vie s r beyli, a eve nd to pla d to be accura ce o te and rder reliabl s e , pl . Ho ease co wever, no 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 ntact Hittite Microwave Corporation: One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106 rights of third parties that may result from its use. Specifications subject to change without notice. No
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