HMC-ALH444 View Datasheet(PDF) - Hittite Microwave
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Description
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HMC-ALH444 Datasheet PDF : 6 Pages
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v03.0410
HMC-ALH444
GaAs HEMT MMIC LOW NOISE
AMPLIFIER, 1 - 12 GHz
1
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 film substrates are recommended for bringing RF to and from the chip
(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)
thick molybdenum heat spreader (moly-tab) which is then attached to the
ground plane (Figure 2).
0.102mm (0.004”) Thick GaAs MMIC
0.076mm
(0.003”)
Wire Bond
RF Ground Plane
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).
0.127mm (0.005”) Thick Alumina
Thin Film Substrate
Figure 1.
Handling Precautions
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-
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.
0.076mm
(0.003”)
Wire Bond
Cleanliness: Handle the chips in a clean environment. DO NOT attempt
to clean the chip using liquid cleaning systems.
RF Ground Plane
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.
0.150mm (0.005”) Thick
Moly Tab
0.254mm (0.010”) Thick Alumina
Thin Film Substrate
Figure 2.
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 has fragile air bridges and should not be touched with vacuum collet, tweezers, or fingers.
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 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 fillet 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 thermosonically bonded
with a force of 40-60 grams. DC bonds of 0.001” (0.025 mm) diameter, thermosonically 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).
For price, delivery and to place orders: Hittite Microwave Corporation, 20 Alpha Road, 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
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