Datasheet HMC902 (Analog Devices) - 10

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HMC902 Data Sheet MOUNTING AND BONDING TECHNIQUES FOR MILLIMETERWAVE GaAs MMICS
The die is attached directly to the ground plane eutectically or
Storage
with conductive epoxy (see the General Handling section, the All bare die are placed in either waffle or gel-based ESD protective Mounting section, and the Wire Bonding section). containers and then sealed in an ESD protective bag for shipment. The 50 Ω microstrip transmission lines on 0.127 mm (5 mil) After opening the sealed ESD protective bag, store all die in a thick alumina thin film substrates are recommended for bringing dry nitrogen environment. RF to and from the HMC902 (see Figure 20). When using
Cleanliness
0.254 mm (10 mil) thick alumina thin film substrates, the die is raised 0.150 mm (6 mil) so the surface of the die is coplanar Handle the chips in a clean environment. Do not attempt to with the surface of the substrate. One way to accomplish this is clean the chip using liquid cleaning systems. to attach the 0.102 mm (4 mil) thick die to a 0.150 mm (6 mil)
Static Sensitivity
thick molybdenum heat spreader (moly tab), which then attaches Follow ESD precautions to protect against ESD strikes. to the ground plane (see Figure 21).
Transients 0.102mm (0.004") THICK GaAs MMIC
Suppress instrument and bias supply transients while bias is applied. Use the shielded signal and bias cables to minimize inductive pickup.
WIRE BOND 0.076mm General Handling (0.003")
Handle the chip along the edges with a vacuum collet or with a sharp pair of bent tweezers. The surface of the HMC902 has
RF GROUND PLANE
fragile air bridges and must not be touched with the vacuum collet, tweezers, or fingers.
0.127mm (0.005") THICK ALUMINA
020
THIN FILM SUBSTRATE Mounting
14525- Figure 20. Routing RF Signal The HMC902 is back metallized and can be die mounted with gold tin (AuSn) eutectic preforms or with electrically conductive epoxy. The mounting surface must be clean and flat.
0.102mm (0.004") THICK GaAs MMIC WIRE BOND Eutectic Die Attach 0.076mm (0.003")
An 80% gold/20% tin preform is recommended with a work surface temperature of 255°C and a tool temperature of 265°C. When hot 90% nitrogen/10% hydrogen gas is applied, the tool tip temperature is 290°C. Do not expose the chip to a temperature
RF GROUND PLANE
greater than 320°C for more than 20 sec. No more than 3 sec of scrubbing is required for attachment.
0.150mm (0.006") THICK 0.254mm (0.010") THICK ALUMINA
021
MOLY TAB THIN FILM SUBSTRATE Epoxy Die Attach
14525- Apply a minimum amount of epoxy to the mounting surface so Figure 21. Routing RF Signal with Moly Tab that a thin epoxy fillet is observed around the perimeter of the Microstrip substrates are placed as close to the die as possible to HMC902 after it is placed into position. Cure epoxy per the minimize bond wire length. Typical die to substrate spacing is schedule of the manufacturer. 0.076 mm to 0.152 mm (3 mil to 6 mil).
Wire Bonding HANDLING PRECAUTIONS
RF bonds made with two 1 mil wires are recommended. These Follow the precautions detailed in the following sections to bonds are thermosonically bonded with a force of 40 g to 60 g. avoid permanent damage to the device. DC bonds of 0.001 in (0.025 mm) diameter, thermosonically bonded, are recommended. Create ball bonds with a force of 40 g to 50 g and wedge bonds at 18 g to 22 g. Create bonds with a nominal stage temperature of 150°C. A minimum amount of ultrasonic energy is applied to achieve reliable bonds. All bonds are as short as possible, less than 12 mil (0.31 mm). Rev. D | Page 10 of 13 Document Outline FEATURES APPLICATIONS FUNCTIONAL BLOCK DIAGRAM GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ELECTRICAL SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS INTERFACE SCHEMATICS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION APPLICATIONS INFORMATION MOUNTING AND BONDING TECHNIQUES FOR MILLIMETERWAVE GaAs MMICS HANDLING PRECAUTIONS Storage Cleanliness Static Sensitivity Transients General Handling Mounting Eutectic Die Attach Epoxy Die Attach Wire Bonding TYPICAL APPLICATION CIRCUITS ASSEMBLY DIAGRAMS OUTLINE DIMENSIONS ORDERING GUIDE