Science/Engineering/Technical forums

That's really rocking, Jerry. I take back all my comments on intermittent forepumps for this - if you're doing quick-turn evap, it just won't be in the picture. I did my evap by rewinding (adding a few turns) to a spot welding transformer, then controlling the AC HV side of that with a variac and SSR. The inrush current for tungsten boats is serious biz - 5 or 10 times the rated "running" current, depending on temps.
That can be awefully brutal to switch on the LV side...it's bad enough on the HV side! I tried a HW store dimmer first - fried it, bought a special 2kw one, it kinda worked, but the variac and switch were the best in the end.
I'll be puttling all that out again to use it soon myself. Fusors make a lot fewer X rays if the inside tank walls aren't as high-Z (stainless). I'll be putting down either Ti or Be for a thin coat (the Be has potential other advantages there...maybe). We're trying to get output of course, but I personally would like a low-rad diet, and prevention is kind of a neater way when you can do it.

It followed me home... Honest...

Cha Vacuum Evaporator by macona, on Flickr

Hah, you could dupe my fusor stuff now! If you care, I'll pm you a few tricks we're waiting for a patent on. No point doing this if $BIGCORP can be first to file when I invented it. Sorry everyone else, you'll just have to wait a little bit. Some "patent reform" law got in the way of us being completely open in a timely way. Plan A is still to give this away - but I (or we here) have to own it or someone can legally steal it from us all. Best patent law $BIGCORPS could buy....keep us upstarts out of the picture, or use us for free R&D - then steal it and monopolize it. Not gonna happen on my watch.

Some more pics of the new system. This system came from a company called SITe, it was a spinoff company from Tektronix that made top of the line scientific grade CCDs. The Imaging Spectrograph in the Hubble uses one of their CCDs. http://www.stsci.edu/hst/stis/design/detectors/

About 11 years ago the company went under and everything went into storage. One of the items was this coater still bearing old tektronix tags. They finally had no money to store it any longer so it is all being disposed of and I got this guy.

20" Base plate with water cooled stainless bell jar and has a motor drive for planetaries inside. There are three planetaries for 4" wafers and one for 6". It uses a 6" Varian diffusion pump with a water and LN2 cooled cold trap and a VAT gate valve on top of that. The whole thing was originally made by Veeco and either was made with parts from CHA or heavily modified over the year with CHA parts. The jar, lifter, and some of the controls were all made by them.

Inside is the evaporator boats, currently set up for aluminum, copper, and gold, the shutter, and substrate heaters. The boats are heated from a transformer with pneumatic switching that goes up to 500 amps and regulated by a variac. Another variac controls the substrate heater lamps (500w, 120v quartz lamps)

It has a Cooke ion guage controller and a old Veeco thermocouple gauge controller. For film control it has an old Airco Temescal FDC-8000. A lot of this stuff will be replaced with some newer units I have lying around.

Veeco 770 vacuum coater by macona, on Flickr

Looking up in the bell jar. The little hole in the center is where the crystal thickness monitor is.

Veeco 770 vacuum coater by macona, on Flickr

These are the evaporator boats. Aluminum on the left, copper in the center, and gold on the right.

Veeco 770 vacuum coater by macona, on Flickr

This looks like it was meant to put down a LOT of metal. My little evap experiments worked all too well, and this is at least 10x of those. I may want to mirror the inside of my fusor tank to help with UV photoionization of the D out in the main tank, and SS isn't as good a reflector for VUV as some other things.

It came with lots of spare boats and some deposition media. Chromium, titanium, aluminum, copper, and i know where a bottle of nickel pellets is.

I have spent the past week or so getting this new system running. Ran into a huge problem with the cooling system, the water line feeds the diff pump, the water cooled feedthroughs, the jar, the ferrofluidic rotary feedthrough, and the crystal sensor holder. I had 31 bad brass fittings. Almost every flare fitting had at least one crack down the length of it and some almost crumbled. Swagelok fittings just snapped in half, and ever big heavy brass tees and street 45's had cracks right down the length. Mind you this system has been kept in a heated warehouse so there was no freezing. I really have no idea what caused this, I have never seen brass act like this. My best guess is they were not using RO/DI water in the loop and some sort of electrolysis set in with power running from the water cooled feedthroughs that supply power to the evaporating boats. Its only a couple volts but that could be all it took.

Or it could have been something in the water. The reservoir for the cooler had a layer of foam in it when it first started circulating. I flushed it out and it is now running clean with RO/DI water.

Thats all fixed now and the flow meter got new o-rings as well. Got it down to the low -7 last night, with LN2 in the trap I should be able to get down to the -8. The cooler might be a little small for the pump and system. The lines were starting to get above ambient, I may have to add a secondary radiator.

All of the fittings I replaced, eventually I will section a couple of them and check them out with the SEM and EDX to see of there was a change in the alloy radially through the part:

Untitled by macona, on Flickr

New plumbing for the feedthroughs with copper flares, push on connectors, and polyurethane tubing.

Untitled by macona, on Flickr

Foam on the water.

Untitled by macona, on Flickr

One of the many split fittings:

Broken water fittings by macona, on Flickr

It's alive!

Veeco 770 Cha 600 coater by macona, on Flickr

Coated a microscope slide with copper last night.

Looking inside the chamber off a mirror at the tungsten boat that holds the copper to be evaporated.

Thermal Evaporation by macona, on Flickr

The coated slide:

Thermal Evaporation by macona, on Flickr

Saweeeet! I presume via evap? I use slides here too as test media - nice clean surface and nicely flat so flaws are obvious. Cool stuff, Jerry

Ive had more time on my hands than I would have liked and have been trying to get these systems modified. On the thermal evaporator I decided to remove the diffusion pump and install a turbo pump I got from a friend. It's a 1000l/s Pfeiffer. To run this machine without getting back streaming I would have to use liquid nitrogen which is not really a big deal, it is just annoying. I did have to replace the bearing in the turbo and find oil for it, it is an incredibly specific fomblin oil that is something like $150 for 35ml, and the pump needs 65. Someone pointed me to some on ebay and I snagged that.

Big problem was the pump has a 10" conflat fitting and the Diff pump was a 6" ASA. My friend at PSU gave me a 6" ASA flange with a piece of 6" tubing already welded to it and a 10" conflat flange that also had a piece of tubing. I had to machine out the conflat and machine a o-ring groove. Tigged them together and it appears to be vacuum tight.

IMG_6201 by Jerry Biehler, on Flickr

IMG_6202 by Jerry Biehler, on Flickr

IMG_6203 by Jerry Biehler, on Flickr