Chip devices and Wire Bonding
Nowadays many devices are available to operate up to the millimeter
wave range, however encapsulated versions are not available much above
26GHz. To use these new devices we must have access to the
equipment required to handle, install and connect them.
Wire bonding a connection to a chip device is obviously as old the semiconductor industry itself however we donít usually deal with this problem as we use encapsulated devices all the time.
I presented an article in DUBUS-2/2004 with an overview of the wire bonding techniques, a possible application for the typical low-budget ham experiments and also added a bit of my personal experience in this field. Full article of DUBUS-2/04 can be viewed here, Wire Bonding (For Microwave and Millimeter-Wave, on a low budget).
My wedge bonding machine
The machine below was made using the head of an old Tempress
wedge bonding machine. All other parts were built from scratch.
By using a precise mechanism and controling it by software (something that is no longer a problem using any of the many good microcontrollers available) it is possible to achieve the performance of a big $$$ comercial machine.
The machine in operation / First Bonds
My Gap Welder / Reflower
The machine below was made using the a surplus Hughes VTA90 head.
The power supply (a constant voltage pulsed supply) was developed
from scratch in order to incorporate the benefits that modern
technology can give. It is possible to control the pulse duration
with millisecond resolution and voltage with 10mV resolution.
Pulsed currents up to 500A are possible.
By setting the right parameters it can be used for chip bonding by reflowing on the substrate and to perform very small solder joints. By setting higher voltages and shorter pulses it is possible to do gap welding also.
The machine in operation / test weld and test reflow.
Inside my wedge bonding machine during construction
Inside my gap-welder supply during construction
I've started an email group solely dedicated to chip devices and etc.
The group is dedicated to uncapsulated devices Si and GaAs etc, covering the discussion on devices,assembly, chip attachment wire bonding etc, towards repair and new circuit design for all areas of hybrid circuits namely for microwave and millimeterwave applications. This group is targeted to both amateurs and small companies that deal with those devices and technologies.
Feel free to join.
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