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Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061
hmm... maybe those fried IGBTs (or defective new ones) can be repaired or at least patched up by cutting out the blown sections? (most are several identical IGBTs on the same substrate with separate wire bonds)
ideas:- modified PS3 laser module stepper motors as these have 5mm throw at ridiculous levels of precision
what would also work is three laser positioner units from old CDROM drives, x/y/z for not much money.
Registered Member #56
Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445
All of the failed to-247 type transistors I have used have had the whole die vaporize (I am sure you have seen the pictures of what a IGBT looks like after a bad failure). In the large 'brick' type dies it is probably quite possible to just use a tweezers to remove the wirebonds to a fried die, but all of the damaged bricks I have come across had all of the dies vaporized so it wouldn't help much in any case. The diodes still work great though!
Registered Member #1667
Joined: Sat Aug 30 2008, 09:57PM
Location:
Posts: 374
Nice one, Steve! I'd like to see someone cut out parts of a power semiconductor but even more tempting will be to buy LEDs as cut wafers on blue tape and assemble higher density LED displays on glass.
I don't trust resistive heating and spark preconditioning of the bonding wire very much when it comes to homebrew solutions. However, I can imagine a solid state laser performing the actual heating.
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061
yep that would work.
otoh, i did wonder about using old ITO glass from a defunct touchscreen (I have two) and then etching it into strips. Put LEDs between two sheets of glass and voila!
(a single piece of copper clad could replace one of the ITO layers)
Another idea is to use self assembly. put tiny drops of solder paste onto the pads then heat up the substrate to 150C or so and solder the assembly in one go with heat from above. The best bet for this would be GaN on SiC based LED chips as they have top and bottom contacts.
Registered Member #311
Joined: Sun Mar 12 2006, 08:28PM
Location:
Posts: 253
Problem with LEDs and ITO is that readily available ITO (LCDs, touchscreens, heated freezer cabinet door glass) is too resistive. While it can and has been done, it needs a rather thick coating to get the resistivity down. Patterened ITO thick enough for LEDs is fairly visible
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IGBT repair using homemade wirebonder?
