MICROWAVE CORPORATION

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12 Elizabeth Drive, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373

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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 Han-

dling, Mounting, Bonding Note).

50 Ohm Microstrip transmission lines on 0.127mm (5 mil) thick alumina thin film substrates are recommended for bring-

ing 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 0.150mm (6 mil) thick molybdenum heat spreader

(moly-tab) which is then attached to the ground plane (Figure 2).

Microstrip substrate should be brought as close to the die as possible in order to minimize ribbon bond length. Typical

die-to-substrate spacing is 0.076mm (3 mils). Gold ribbon of 0.075mm ( 3 mil) width and minimal length <0.31mm (

<12 mils) is recommended to minimize inductance on RF ports.,

v02.1201

HMC331

GaAs MMIC FREQUENCY

DOUBLER, 12 - 18 GHz INPUT

MMIC Assembly Techniques for HMC331

3 mil Ribbon Bond

3 mil Ribbon Bond

Ribbon Bond

Ribbon Bond