Each bottom electrode is connected to a wire bonding pad
. A top electrode is used as a common electrode and is electrically connected to the upper part of the bottom substrate through an Sn/Au bonding pad
and then to the wire bonding pad
at the upper side of the bottom substrate, acting as the common ground.
The connections between chips and circuit boards traditionally are made from pre-fabricated metal wires that connect to a designated bonding pad
on a chip.
Shrinking bonding pad
size has only made probing more difficult.
Kirchgessner, "Bonding Pad
Models for Silicon VLSI Technologies and Their Effects on the Noise Figure of RF NPNs," IEEE Microwave and Millimeter-wave Monolithic Circuits Symposium Digest, 1994, pp.
Lovelace, "Bonding Pad
Models for Silicon VLSI Technologies and Their Effects on the Noise Figures of RF NPNs," IEEE Microwace and Millimeter-wave Monolithic Circuits Symposium Digest, 1994, pp.
The combination of the T-section, wire bond and bonding pad
on the MMIC establishes a predetermined characteristic impedance (50 [omega]) over a certain frequency range.
The width of the final deformed bond can be the same size as the bonding pad
, if not larger.
The geometry uses a multifeed T gate layout with the two small side gate pads connected to the central gate bonding pad
by an air bridge.
This electrode extends over all 30 cells and connects to the bonding pads
(not shown in the image) via the surface conductors at one side for the first phase and on the other side for the second phase.
In fact, bonding pads
could melt if precautions were not taken.