AMPLIFIERS - LINEAR & POWER - CHIP
10
HMC7149
10 WATT GaN MMIC POWER AMPLIFIER,
6 - 18 GHz
0.102mm (0.004”) Thick GaN 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
Mounting & Bonding Techniques for GaN MMICs
The die should be eutectically attached directly to the ground plane (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 accomplish this is to attach the 0.102mm (4 mil) thick die to a
copper tungsten or CuMo heat spreader which is then attached to the
thermally conductive ground plane (Figure 2).
Microstrip substrates should be placed 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
protective 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 ESD
strikes.
Transients: Suppress instrument and bias supply transients while bias
is applied. Use shielded signal and bias cables to minimize inductive
pick-up.
Die placement: A heated vacuum collet (180°C) is the preferred method of pick up. Ensure that the area of vacuum
contact on the die is minimized to prevent cracking under differential pressure. All air bridges (if applicable) must be
avoided during placement. Minimize impact forces applied to the die during auto-placement.
Mounting
The chip is back-metallized with a minimum of 5 microns of gold and is the RF ground and thermal interface. It is
recommended that the chip be die mounted with AuSn eutectic preforms. The mounting surface should be clean
and at.
Eutectic Reow Process: An 80/20 gold tin 0.5mil (13um) thick preform is recommended with a work surface tem-
perature of 280°C. Limit exposure to temperatures above 300°C to 30 seconds maximum. A die bonder or furnace
with 95% N2 / 5% H2 reducing atmosphere should be used. No organic ux should be used. Coefficient of thermal
expansion matching is critical for long term reliability.
Die Attach Inspection: X-ray or acoustic scan is recommended.
Wire Bonding
Thermosonic ball or wedge bonding is the preferred interconnect technique. Gold wire must be used in a diameter
appropriate for the pad size and number of bonds applied. Force, time and ultrasonics are critical parameters: opti-
mize for a repeatable, high bond pull strength. Limit the die bond pad surface temperature to 200°C maximum.
For price, delivery and to place orders: Analog Devices, Inc., 1 Technology Way, P.O. Box 9106, Norwood, MA 02062-9106
Phone: 781-329-4700 • Order On-line at www.analog.com
Application Support: Phone: 1-800-ANALOG-D
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