Sciencemadness Discussion Board - A very simple circuit created on a piece of glass

A very simple circuit created on a piece of glass

wish i had a kraken!!! - 28-10-2014 at 22:06

DrMario - 28-10-2014 at 23:55

Is that a PCB glued to a microscope slide?
I recognize the circuit, BTW: it's an astable multivibrator with two bipolar transistors.

[Edited on 29-10-2014 by DrMario]

wish i had a kraken!!! - 29-10-2014 at 00:40

Dear DrMario , U have trained eyes! yes , It is an astable multivibrator with two bipolar transistors ! :-) BUT U know it is coated on Microscope Slider!

[Edited on 29-10-2014 by wish i had a kraken!!!]

Masked Slider right after being coated by copper!

[Edited on 29-10-2014 by wish i had a kraken!!!]

[Edited on 29-10-2014 by wish i had a kraken!!!]

Good Job!

WGTR - 29-10-2014 at 06:15

Did you use adhesive-backed copper tape, or did you glue copper foil to the glass with epoxy, and then etch? How did you etch it, mechanically or chemically?

Praxichys - 29-10-2014 at 06:25

I'm secretly hoping the answer is sputtering followed by electron beam lithography.

WGTR - 29-10-2014 at 06:40

I'm afraid it looks like foil, attached with some type of adhesive!

I did the same thing once, with copper foil and epoxy. The foil was pressed onto the glass with an old typewriter roller. The idea was to push out almost all of the epoxy from under the copper. From there, the foil was masked with photo-film and exposed to UV through a positive. After developing, and then etching with ferric chloride, the circuit board pattern on glass was used as a negative for other exposures.

At the time, I was interested in making durable negatives for production PCB work, but I have moved on to other methods.

wish i had a kraken!!! - 29-10-2014 at 09:04

Quote: Originally posted by WGTR

Did you use adhesive-backed copper tape, or did you glue copper foil to the glass with epoxy, and then etch? How did you etch it, mechanically or chemically?

I did not used adhesive-backed copper tape :-D I used sputtering instead , First I draw the circuit lines on a pice of Al foil then using a sharp razor I cut the lines out after that I covered the Microscope slider with the foil the I sputtered it !

wish i had a kraken!!! - 29-10-2014 at 09:07

Quote: Originally posted by Praxichys

I'm secretly hoping the answer is sputtering followed by electron beam lithography.

Bravo :-) U nailed it ! It is sputtering but I did not used electron beam lithography (I don't have such a thing yet !)

DrMario - 29-10-2014 at 09:37

Quote: Originally posted by Praxichys

I'm secretly hoping the answer is sputtering followed by electron beam lithography.

I'm partly with you: I hope it's sputtering of an adhesive layer (titanium, chromium or Ti/W) and then copper on top.

However, to achieve a thick enough layer for soldering, copper should be electrodeposited. With sputtering you can deposit up to about 2 µm of copper before the lab technician releases the hound dogs at you (at 1 µm they already start barking). Not enough for soldering.

BUT THEN... no electron beam because that's too freaking slow. Even one mm2 of surface patterned by electron beam lithography can take from a quarter of an hour to an hour.

No - my hope is that the poster used the best tool for the job: traditional lithography.

But the quality of the surface tells me that this probably is not the case.

DrMario - 29-10-2014 at 09:39

Quote: Originally posted by wish i had a kraken!!!

Quote: Originally posted by WGTR

Did you use adhesive-backed copper tape, or did you glue copper foil to the glass with epoxy, and then etch? How did you etch it, mechanically or chemically?

So you used the aluminium foil as shadow mask?

EDIT: more questions: did you use an adhesion layer? How thick is your copper layer? Finally: isn't this a rather expensive way to make such a simple circuit board? There's also the fact that this is less robust than normal PCBs, for several reasons. It is more thermally resistant than a PCB, but the elements themselves aren't, anyway.

I can, however, appreciate the exercise. However, at our institution, every hour of sputter time costs 100 EUR. Unless you have sputtered that microscope slide alongside your main sample, you've saddled a project with a non-negligible expenditure.

[Edited on 29-10-2014 by DrMario]

jock88 - 29-10-2014 at 13:34

Why is sputtering so expensive?
Can a dude not make his own sputtering apparatus.
You do need a vacuum system buts after that it all plain sailing???????

DrMario - 29-10-2014 at 14:30

Unless it's one of those mini sputters used to deposit a few nm of gold on samples for SEM, it's an expensive piece of kit (high fixed cost) and it usually needs maintenance by an engineer with considerable experience with vacuum technology. This person's salary is a running cost. In our case, some of our vacuum equipment (one sputter, one RIE, one PECVD, a DRIE and yes, one of those cheap little sputters outside of the cleanroom) is maintained by an actual researcher. Yes, there's some cost in maintaining the external pump that runs 24/7, there's some cost in the form of target consumption, etc. And of course, since this is a research cleanroom the targets need to be replaced/rotated from time to time - usually tungsten is swapped for platinum, and chromium and titanium may be swapped sometimes.

All this adds up.

Now we do have one of those cheapo mini sputters outside of the cleanroom, but that thing is not suitable for depositing significant amounts of material, it can only have one target at a time, and still needs maintenance. So it's cheaper than the big sputters, but we still get to pay €50/hour for usage.

Dr.Bob - 29-10-2014 at 17:02

Wow, I worked with some E-beam lithography about 30 years ago, and yes, it was slower than watching paint dry, but able to make some incredibly complex chips very well and with what were very fine lines back then. Did a coop doing mostly photolithography using photoresists on silicon wafers. It was a neat experience, but then I went into more organic chemistry, since most of the chemistry of electronics was really nasty back then. We used boiling sulfuric acid, HF, PH3, AsH3, and many other lovely compounds. Also NF3 and others to clean CVD chambers. I mostly did the cross linking work, testing various condinions, which was boring compared to much of the other work. But I helped fix other things as well. That was so long ago that the chips were not even CMOS, but old NPN type. Wish I had kept more of the stuff from them, it would be great for the Smithsonian. I do still have some Core memory somewhere...

[Edited on 30-10-2014 by Dr.Bob]

DrMario - 29-10-2014 at 20:06

I'll hazard a guess that you used phosphine and arsine (lovely name, that) only for ion implantation. Our ion implanter uses phosphine, arsine and borine. The main user of the ion implanter suggested running as fast as possible, should there be any leak of these gases, but generally I feel rather safe, as these aren't handled in a manual way and there is a lot of fool-proof mechanisms built into that godawful, huge and loud machine.

The etchant solution haven't gotten any nicer since you worked in a cleanroom, though EDP or hydrazine are thankfully not used for crystallographic etching of silicon, anymore. On the other hand, TMAH crystallographic etching is very popular, in spite of the fact that it can release some battlefield gases with some silicon dopants.

Chlorine gas is used for DRIE, along with the much more docile SF6 (I guess DRIE wasn't yet used, back when you were doing your bipolar transistor ICs).

HF is as common as ever. We use tons of the stuff.

So all in all, I'd say things have not become much safer, although our safety protocols are annoyingly thorough. I've yet to work in any chemistry lab that has even close to the safety margins that we employ, but I won't bore you with details.

wish i had a kraken!!! - 30-10-2014 at 08:41

Quote: Originally posted by DrMario

Dear DrMario I did not used adhesive layers such as those U mentioned I just used Copper , and :-) I didn't feel worry about hound dogs! Cuz I used (and am using) my own made sputter coater :-)

DrMario I don't know anything about the thickness of coated
layer (I used my homemade sputter coater it is not equiped with the device which monitors the thickness of coated layer )
If U know any practical method for measuring the thickness of coated layer I would be really glad if U share it with me :-).

I did not want to use this method for making PCBs I just wanted to show that my homemade sputter coater is capable of depositing a layer of copper , I then mounted electronic components to prove that I have achived a good sputter coated layer of Copper. :-)

[Edited on 30-10-2014 by wish i had a kraken!!!]

DrMario - 30-10-2014 at 08:55

Quote: Originally posted by wish i had a kraken!!!

Dear DrMario I did not used adhesive layers such as those U mentioned I just used Copper , and :-) I didn't feel worry about hound dogs! Cuz I used (and am using) my own made sputter coater :-)

I am very impressed!!! Can you please share more info on your self-made sputter? Some pics? Diagrams? Maybe make a youtube video of it?

Do you also make your own targets, or do you buy commercial ones? What other targets, in addition to copper, do you have?

Do you have a turbopump?

Is it a DC or an AC sputter?

wish i had a kraken!!! - 30-10-2014 at 09:03

Quote: Originally posted by DrMario

Quote: Originally posted by wish i had a kraken!!!

Dear DrMario I did not used adhesive layers such as those U mentioned I just used Copper , and :-) I didn't feel worry about hound dogs! Cuz I used (and am using) my own made sputter coater :-)

Happy to hear that :-) It is a DC-magnetron sputter coater , I don't have a turbopump :-( (Just a vacum pump capabale of reaching 0.02 mbar ), And I tested Aluminium and it was not a successful test then I am going to test Ti soon :-)

wish i had a kraken!!! - 30-10-2014 at 09:17

U can see Plasma and sample holder :-)

In my design cathode is located at the buttom but soon I became aware that this is not a good design and needs to be changed ;-)

[Edited on 30-10-2014 by wish i had a kraken!!!]

WGTR - 30-10-2014 at 13:38

Woop! Woop!

"Fun police, here! There have been reports of someone having too much fun in the lab. We are here to investigate. Yup, looks like we're going to have to write you a ticket."

This is quite an interesting project. I didn't realize at first what you did, since the aluminum foil looked like copper. I use a small sputter coater for SEM work, but don't use it for other things since it takes so long to pump down. For copper plating glass I either use electroless copper onto silver or electroplated copper onto conductive glass. How much money do you have invested in the project? How long did it take you to put the project together? Did you follow a set of plans, or develop it yourself?

Pretty cool.

wish i had a kraken!!! - 30-10-2014 at 23:40

Quote: Originally posted by WGTR

Woop! Woop!

"Fun police, here! There have been reports of someone having too much fun in the lab. We are here to investigate. Yup, looks like we're going to have to write you a ticket."

This is quite an interesting project. I didn't realize at first what you did, since the aluminum foil looked like copper. I use a small sputter coater for SEM work, but don't use it for other things since it takes so long to pump down. For copper plating glass I either use electroless copper onto silver or electroplated copper onto conductive glass. How much money do you have invested in the project? How long did it take you to put the project together? Did you follow a set of plans, or develop it yourself?

Pretty cool.

HAHAHAHA , Hope they(Fun Police) won't send me to the jail!

I will give U more info about it or maybe I will add a topic in technochemistry

for now watch these pics :-)

[Edited on 31-10-2014 by wish i had a kraken!!!]

DrMario - 31-10-2014 at 02:02

Quote: Originally posted by wish i had a kraken!!!

U can see Plasma and sample holder :-)

In my design cathode is located at the buttom but soon I became aware that this is not a good design and needs to be changed ;-)

[Edited on 30-10-2014 by wish i had a kraken!!!]

Please give us/me more info, diagrams, instructions, pump model.... or else I will call the fun police! Or something!!

BTW, if you had trouble sputtering Al, you'll have even more trouble sputtering Ti. If you can get ahold of tungsten, try that. Also nickel.

wish i had a kraken!!! - 31-10-2014 at 02:22

Quote: Originally posted by DrMario

Quote: Originally posted by wish i had a kraken!!!

Dear DrMario , soon I will give U more info about it in fact I have plans to add a topic about it in technochemistry :-D

I don't know what is wrong with Aluminium , maybe it requires lower vaccum pressur , maybe insted of Ar I should use Ne , I really don't Know! :-(

I really don't know what to do with Al !!! I really applogize my Language but it is a real pain in the ass!

[Edited on 31-10-2014 by wish i had a kraken!!!]

[Edited on 31-10-2014 by wish i had a kraken!!!]

DrMario - 31-10-2014 at 10:03

Quote: Originally posted by wish i had a kraken!!!

I don't know what is wrong with Aluminium , maybe it requires lower vaccum pressur , maybe insted of Ar I should use Ne , I really don't Know! :-(

I really don't know what to do with Al !!! I really applogize my Language but it is a real pain in the ass!

I think it's pretty simple: aluminium is very reactive and will create oxide and nitride even in low pressure air. Basically what you're doing is reactive sputtering (i.e. sputtering in a reactive atmosphere).

In any case, I don't think you should replace Argon with Neon. Neon's ionization energy is 21.5 eV, quite a bit higher than Argon's.

wish i had a kraken!!! - 31-10-2014 at 13:06

Quote: Originally posted by DrMario

Quote: Originally posted by wish i had a kraken!!!

I filled the chamber with Ar and then vaccumed it and .... so I think there is no chance for Al to be Oxidized !

I also think it is not a good Idea to replace Ar But I wanted to replace Ar by Ne because Ne ions are lighter than Ar ions and I think Ar Ions have too much energy which cause in inefficiency of sputtering of Al ! but I am not Sure!

[Edited on 31-10-2014 by wish i had a kraken!!!]

wish i had a kraken!!! - 9-1-2015 at 06:32

I just made a video of it ! U can see it here : https://www.youtube.com/watch?v=VGmFLUNf0nE

subsecret - 10-1-2015 at 06:32

A heavy silver mirror might be a good way to make these glass circuits, as most electrical solder contains silver and lead, and would more easily bind to the surface than to copper.

Also, what if some areas were waxed (like with FeCl₃ etching) and the slide was placed in the mirroring solution? The material would only be plated in the circuit paths which is additive, as compared the normal subtractive method of etching. This would save the steps of copper recovery from the spent etchant.

Very neat experiment, though I'm not particularly familiar with sputtering.

wish i had a kraken!!! - 12-1-2015 at 11:11

Dear Awesomeness , this work is done using a sputter coater machine (I will upload a video about it soon :-) ) , using this technology gives us the advantage of having deposited layer of different types of metals or materials on different types of surfaces .

By the way would U explain more about waxing by FeCl3 ? I think Its a cool Idea ! Is it done by submerging the slide in a solution of FeCl3 and then having the slide dried ? What solvent U use ? Alcohol + water or something else?

subsecret - 13-1-2015 at 11:13

True, I suppose you get more selectivity with a sputtering process.

I've never made PCBs by any method, but the etching works something like this:

First, a board completely coated in copper has the paths drawn on it with wax, or some other protecting material. Then, the entire board is submerged in aqueous FeCl3, which reacts with the copper to form copper chloride, and the iron (III) is reduced to (II), so it doesn't plate onto the PCB. The board is then rinsed, and any copper not covered by the protector is removed. This is how commercial boards are made.

mayko - 13-1-2015 at 11:59

It might not function well for small circuits, but there is electrically conductive spraypaint available.

Someone Who Isn't Me has used this to make graffiti circuits - put together a small board with an LFO, epoxy it to a wall, and spray on a crude keyboard. Someone touches a 'key' and it uses their body as a resistor, playing a tone.

wish i had a kraken!!! - 8-3-2015 at 04:28

Dear friends You can see my sputter coater machine here : https://www.youtube.com/watch?v=AGiX8Rh-GGI&feature=yout...