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 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 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 flat.

Eutectic Reflow 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% N

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

v

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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