For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com
Application Support: Phone: 978-250-3343 or apps@hittite.com
LINEAR & POWER AMPLIFIER - CHIP
6
HMC451
v03.0913
GaAs PHEMT MMIC MEDIUM
POWER AMPLIFIER, 5 - 20 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).
50 Ohm Microstrip transmission lines on 0.127mm (5 mil) thick alumina
thin lm substrates are recommended for bringing RF to and from the chip
(Figure 1). If 0.254mm (10 mil) thick alumina thin lm 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)
thick molybdenum heat spreader (moly-tab) which is then attached to the
ground plane (Figure 2).
Microstrip substrates should be located as close to the die as possible
in order to minimize bond wire length. Typical die-to-substrate spacing is
0.076mm to 0.152 mm (3 to 6 mils).
Handling Precautions
Follow these precautions to avoid permanent damage.
Storage: All bare die are placed in either Waffle or Gel based ESD pro-
tective containers, and then sealed in an ESD protective bag for shipment.
Once the sealed ESD protective bag has been opened, all die should be
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.
Static Sensitivity: Follow ESD precautions to protect against > ± 250V
ESD strikes.
Transients: Suppress instrument and bias supply transients while bias is
applied. Use shielded signal and bias cables to minimize inductive pick-up.
General Handling: Handle the chip along the edges with a vacuum collet
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 collet, tweezers, or ngers.
Mounting
The chip is back-metallized and can be die mounted with AuSn eutectic preforms or with electrically conductive epoxy.
The mounting surface should be clean and at.
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 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 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. All bonds should be as short as possible <0.31mm (12 mils).
0.102mm (0.004”) Thick GaAs MMIC
Wire Bond
RF Ground Plane
0.127mm (0.005”) Thick Alumina
Thin Film Substrate
0.076mm
(0.003”)
Figure 1.
0.102mm (0.004”) Thick GaAs MMIC
Wire Bond
RF Ground Plane
0.254mm (0.010”) Thick Alumina
Thin Film Substrate
0.076mm
(0.003”)
Figure 2.
0.150mm (0.005”) Thick
Moly Tab
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
For price, delivery, and to place orders: Analog Devices, Inc.,
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106
Phone: 781-329-4700 • Order online at www.analog.com
Application Support: Phone: 1-800-ANALOG-D
