HMC560A Data Sheet
Rev. 0 | Page 28 of 29
MOUNTING AND BONDING TECHNIQUES
Attach the die directly to the ground plane eutectically or with
conductive epoxy. To bring RF to and from the chip, 50 Ω micro-
strip transmission lines on 0.127 mm (0.005˝) thick alumina,
thin film substrates are recommended (see Figure 103).
RF GROUND PLANE
0.102mm (0.004") THICK GaAs MMIC
WIRE BOND
0.127mm (0.005") THICK ALUMINA,
THIN FILM SUBSTRATE
0.076mm
(0.003")
24243-113
Figure 103. Bonding RF Pads to 5 mil Substrate
If using 0.254 mm (0.010˝) thick alumina, thin film substrates,
raise the die 0.150 mm (0.006˝) so that the surface of the die is
coplanar with the surface of the substrate. A way to accomplish
this is to attach the 0.102 mm (0.004˝) thick die to a 0.150 mm
(0.006˝) thick molybdenum heat spreader (moly tab), which is
then attached to the ground plane (see Figure 104). To minimize
bond wire length, place microstrip substrates as close to the die
as possible. Typical die to substrate spacing is 0.076 mm (0.003˝).
RF GROUND PLANE
0.102mm (0.004") THICK GaAs MMIC
WIRE BOND
0.254mm (0.010") THICK ALUMINA,
THIN FILM SUBSTRATE
0.150mm
(0.006") THICK
MOLY TAB
0.076mm
(0.003")
24243-114
Figure 104. Bonding RF Pads to 10 mil Substrate
HANDLING PRECAUTIONS
To avoid permanent damage to the device, follow the
precautions in the following Storage, Cleanliness, Static
Sensitivity, Transients, and General Handling sections.
Storage
All bare dice are placed in either waffle- or gel-based ESD
protective containers and then sealed in an ESD protective bag
for shipment. After opening the sealed ESD protective bag,
store all dice 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 pickup.
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. Do not touch the chip with a vacuum collet,
tweezers, or fingers.
MOUNTING
The chip is back metallized and can be die mounted with gold
(Au)/tin (Sn) eutectic preforms or with electrically conductive
epoxy. The mounting surface must be clean and flat.
Eutectic Die Attach
An 80/20 gold and tin preform is recommended with a work
surface temperature of 255°C and a tool temperature of 265°C.
When hot 90/10 nitrogen(N)/hydrogen (H) gas is applied, the
tool tip temperature must 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 is 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 when the chip is placed into position. Cure epoxy per the
schedule of the manufacturer.
WIRE BONDING
Ball or wedge bond with 0.025 mm (0.00098˝) diameter pure
gold wire is recommended. Thermosonic wire bonding with a
nominal stage temperature of 150°C and a ball bonding force of
40 grams to 50 grams, or a wedge bonding force of 18 grams to
22 grams, is recommended. Use the minimum level of ultrasonic
energy to achieve reliable wire bonds. Wire bonds must begin
on the chip and terminate on the package or substrate. All
bonds must be as short as possible <0.31 mm (0.01220˝).