HMC490_09 Datasheet, PDF (6/6 Pages) Hittite Microwave Corporation – GaAs PHEMT MMIC LOW NOISE HIGH IP3 AMPLIFIER, 12 - 17 GHz

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HMC490
GaAs PHEMT MMIC LOW NOISE
HIGH IP3 AMPLIFIER, 12 - 17 GHz
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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
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).
0.076mm
(0.003”)
Wire Bond
RF Ground Plane
Microstrip substrates should brought as close to the die as possible in
order to minimize bond wire length. Typical die-to-substrate spacing is
0.076mm to 0.152 mm (3 to 6 mils).
Handling Precautions
Follow these precautions to avoid permanent damage.
0.127mm (0.005”) Thick Alumina
Thin Film Substrate
Figure 1.
0.102mm (0.004”) Thick GaAs MMIC
Storage: All bare die are placed in either Waffle or Gel based ESD protec-
tive 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.
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.
RF Ground Plane
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
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).
For price, delivery, and to place orders, please contact Hittite Microwave Corporation:
20 Alpha Road, Chelmsford, MA 01824 Phone: [phone] Fax: [phone]
Order On-line at www.hittite.com
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