Intro to plasma cleaning

I describe how to use plasma to create very clean surfaces on microscope slides. This process is used extensively in the semiconductor industry.

[@RimstarOrg]

Amazing. I had no idea you could create a plasma just by lowering the air pressure and stimulating it with RF. Don't ever stop making these videos!

[@vk2zay]

It is called inductively coupled plasma. It is just like an induction heater, the RF field accelerates the charges in the plasma around keeping it ionised. The only trick is how to achieve the first ionisations that then grow into a full plasma via avalanches. If the field is strong enough it can directly ionise atoms, but generally there are enough ions/electrons available in the gas to almost immediately ignite the plasma even at moderate amplitudes, but at higher pressures the MFP is short and it takes larger amplitude fields to get things going. In limiting conditions it can take a moment for a cosmic ray or decay in the environment to provide some ions to start the discharge, but once established the RF energy keeps it lit. The species in the gas matter too, some things drink up ions and electrons or wash off their energy, quenching the discharge. You can do it even at atmospheric pressure with enough electric field amplitude. It would be almost impossible to do with HF RF at atmospheric pressure, but microwaves and light can be focused tightly enough with practical sized equipment to break down air directly (i.e. magnetrons and lasers).

[@RimstarOrg]

***** It sounds like he used just air starting at 2:12, even referring to it as an air plasma, though he does then talk about the alternative of using pure oxygen.

[@RimstarOrg]

vk2zay Thanks for the detailed answer. Now that you mention it, I've seen it done at atmospheric pressure with microwaves, in microwave ovens, but that's cheating. :) Doing it at RF makes it a fun challenge.

[@maxk4324]

@@vk2zay As well, many models of plasma torches induction to ionize gasses at around atmospheric pressures, although I am pretty sure they use argon which is easier to ionize.

[@cosimoto1]

I work with a ton of Engineers. Man these guys are a bunch of cut and paste, convert the equation to code, check it against past history robots! Thanks for combining hands on creativity with sound technical principles! That is the making of a great teacher!

[@penguinkothe8323]

Wow! Reading about this in papers (with it mostly being used for bonding plastic) I always assumed plasma cleaning was some super advanced thing done with a million-dollar machine, but this actually seems like something I could do at home! Thanks for the video!

[@JustOneAsbesto]

Maybe I'm just a weirdo, but I think this is one of your coolest projects yet.

[@BobbyOfEarth]

I worked in a Custom product development group at Siemens Corp, (medical product development) and while introducing the products into production in our Mfg. facility in Penang Malaysia, any product requiring die attachment or wire bonding had to go thru a plasma cleaning station. Its a very useful process for cleaning oil off leadframes or PCB substrates left from sequential punching or hand processing operations. The feared killer of molded IC's was residual chlorides that.. if allowed to remain on the leadframe would become activated with moisture. By adding an electrical component thru biasing, would allow this contamination to manifest into dendritic growth. This reaction is actually a fern like fractal grow of migrating silver molecules (from the silver die attach epoxy) that would lead to premature DUT failure do to a shorting of the junction of the IC. Very interesting to see this reaction during failure analysis. Great pics of this failure mechanism on the internet. Thanks for sharing...

[@DJChesley]

Your channel has become one of my very favorite. You are an inspiration Ben!

[@artifactingreality]

That's amazing I never knew you could do all this stuff with just a vacuum pump and a bell jar. When I saw you get the bell jar I was thinking ok so what I didn't know it had a million uses.

[@rickr7333]

We use oxygen first, to combine with any contaminates that still exist in the < 10 micron atmosphere. That makes those contaminates heavy enough to be evacuated quickly. Then we use sputtering grade (99.995%) argon to blast off any oxides on the metallic surfaces, for our gold-wire bonding process. One note, we are using gold plated headers and if you leave them in the chamber too long, the argon will blast through the plating, rendering them unusable.

[@nebnoswel]

Hi Rick, can you explain more how argon gets rid of oxides? I was under the impression that you had to use a reactive gas like hydrogen to remove oxides. Thanks!

[@rickr7333]

@@nebnoswel So this is what we do where I work and I maintain the machines but I'm not an expert on the physics exactly. Here is what I understand about the process. The argon in the high frequency field yields very heavy ions in the resulting plasma which blast the surfaces somewhat like a sand blaster but down at the molecular level. The ions being very small blast off material a molecule at a time as opposed to the analogy of sand blasting at a few ten thousands at a time. What we're doing is bonding gold alloy wire between a semiconductor die and the header pins that pass through the metal case. Think of a TO-5 transistor. Why we can't use reactive gases. Once started reaction will continue. If we use hydrogen and we get clean surfaces we weld, we test, everything is good, then send it out into the world and in 3 to 6 months it comes back failed. The reaction was started and unless you do something to stop it, it continues until failure.

[@nebnoswel]

Rick R Thanks so much for the info! So the argon cleaning is basically mechanical but at a small scale as opposed to other plasma cleaning (like hydrogen) which works chemically and can have unintended chemical side effects? That’s fascinating

[@rickr7333]

@@nebnoswel As I understand it basically all of the plasma cleanings are mechanical but some of them leave reactive material behind that can have unstable results in the long term. They all bombard the target with ions within the plasma and those ions strip away material mechanically but some of them leave molecular charges that are reactive.

[@zhungonlyx]

Hi, I have a question. We're using a sputtering machine with 3 guns. Is it possible to use that machine as a plasma cleaner similar to this video? If it is possible, how to do that? Thank you!

[@danheidel]

Nice video! I used to use quite a bit of UV-induced ozone cleaning in grad school. Not quite as effective as plasma cleaning but way simpler and easier - just put the substrate under a very high intensity UV lamp and slowly blow air or O2 across it. You get a ton of O3 that also aggressively attacks the surface. I did want to mention that you can actually get really clean glassware with regular washing if you do it right. I would have a giant Tupperware bin with a strong Alconox (a brand of scientific cleaner designed for low residue) solution with a circulating heater in it that would keep it at about 70C. (temperature choosen for the maximum I could stand to put my gloved hands into) Put the glassware in that for a few hours. Then give it a good scrub with carefully cleaned brushes while wearing gloves and rinse in filtered, deionized water. You'll get glass that passes the drop test every time.

[@skidmoremusictech528]

Outstanding demonstration and explanation of plasma cleaning! Thanks so much!!!

[@ChrisGammell]

So free. So radical.

[@biltema2000]

Chris Gammell is the name of a guy here in Norway who makes the most delicious foie gras you can think of.

[@joecobra48]

U smell like a free radical

[@teresashinkansen9402]

Ive discovered that the flame of a slightly air rich blow torch (when the flame cone turns from slightly greenish to a deep blue) works pretty good on glass, after a good mechanical cleaning torching the glass chasing the condensation on the glass makes the glass pass the water break test pretty well, the glass just heats up to about 60C° - 70C°.

[@pautorruella2687]

Hey, Nice video! Very well explained! I work extensively with transmission electron microscopes and I thought I'd let you know that we frequently use plasma cleaning in many samples precisely to get rid of organic contanimation, so there you have another application.

[@AndrewSteffenHB]

Just amazing, I am off to build one myself. For some years now I've been wanting to find a way to clean glass beside ultrasonic, Thank You!

[@jaytarro1846]

When the free-flying wake shield facility was deployed from the space shuttle in the 1990s, the active deposition side of the wake shield was first faced toward the direction of travel. This caused atomic oxygen of the space environment to impinge on that side of the wake shield to clean it. It was then oriented in the opposite direction so that the deposition side was in the wake where the vacuum is extremely high, about 1000 to 10,000 times better than vacuum systems on earth. It's a clever method to obtain both cleanliness and very high vacuum.

[@cherylm2C6671]

This sounds like it could be used as part of a heat shield ablation package - maybe not on Venus, but perhaps for lunar entry.

[@何良-x7r]

@@cherylm2C6671 is it possible to fight with propeller cavitation

[@ericlotze7724]

I NEED a Scott Manley video on this, WILD concept that supposedly worked quite well. Thanks for showing me this!

[@RadioTrefoil]

Great video, as always. I might actually research a bit into plasma cleaning. I've always loved near-vacuum plasmas, they are so pretty.

[@andrewhorizon8066]

Subscribed! Great source of info for garage scientists. Love your simple, abrupt, with no reprise or excess, "See you next time" video conclusions.

[@BushCampingTools]

How much fun this must have been to do. I remember using a commercial plasma asher to clean TEM apertures with and remembered how boring it was If only I'd built it the device myself. Great video. I home school and hopefully this is on my list of cool things to do.

[@SkylerF]

RF is so cool. I use it for ham radio, but I really want to expand on the uses and do fun stuff with it.

[@thefuture2025]

Nice vid. I just coated an alumina tube with metal in an evacuated chamber using a variable leak valve and a convection gauge to stabilize a partial pressure of argon to 600 mtorr. The electrode glowed bright blue and purple after I applied the high voltage to the feedthru which was coupled to the electrode. We also clean parts using a glow discharge method sometimes. This vid reminds me of that, thanks for sharing this.

[@FXGreggan.]

This is also possible to do in a microwave oven - in a container inside the microwave of course, just pull two tubes through the side. The plasma cleaners at work also used magnetrons in that exact frequency range...

[@kwinzman]

"I started the cleaning process by lowering the dirty slides into a vacuum chamber" What else? Love this channel!

[@teshk6256]

You should really write a book, you have such a great way of teaching things

[@PaulRonquillo]

This blew my mind more and more every step of the way. I need a reason to build one of these.

[@nickmartinblue]

I always love these videos.

[@vk2zay]

Glad to see the RF source wasn't DOA. So many things you can now attempt!

[@nathanperri8639]

This is the coolest channel ever!

[@clarencecherrone7914]

Could you give us a better description of the equipment you used? As far as the tuner and rf generator.

[@darkobul1]

Ben I am your student. Thanks a lot for sharing all this research of yours.

[@USWaterRockets]

If you use it at a higher power level and intentionally "damaged the substrate" in a desired way using this method, could you in effect use this to polish a surface of an object or lens at a very microscopic level? Great videos! keep them coming!

[@05stickman]

Ben! This is awesome. We do something similar [we use microwave] and use them for wound healing. I'm in SF Bay Area. Could we maybe meet up? I'd love to show you what my company, Adtec Plasma Technology, does! :)

[@haywoodmitchell8322]

Wow Ben. I am impressed. You have some nice gear. I buy whatever I can scavenge from UCSB.... universities are great for that and you can get some really nice stuff for pennies. Only problem is that what you get is random and depends on what they are getting rid of. I would love to check out your workshop and lab someday!

[@Groovewonder2]

You should do a short showing the power needed to give visible damage to a slide, maybe with a super condensed timelapse over how long it needs to become visible.

[@AdelAlouani]

"But does it PlasmaClean?" I really want to see a channel like that.

[@aaronholwick8659]

Ben, I have been absolutely amazed with your knowledge and ability to create and make applications of existing technology for your experiments since I first saw your video on creating freeze dried ice cream. I am really interested in everything that you do on your channel and I was wondering what you majored in and what your profession is, if you do not mind telling me (I understand if you do). I am currently in high school and do not know what I'm going to do but I love to watch and learn from your videos. Thanks for posting such awesome videos!

[@johndoe-bq1xt]

What a rad concept - reduce the atmospheric pressure of air, so you can electrify the remaining gas and then control its movement through EM modulation - back and forth on a surface, like glass. Transferring the Kinetic Energy from the plasma atoms to the surface contaminant atoms and vaporizing them into the GAS ! THEN SUCKING AWAY OR REMOVING THAT GAS !

[@smfield]

"Plasma sandblasting"! Sounds like you can do some cool solar wind experiments with RF windsails. Try applying your aerogels sputtered with several layers of gold.

[@frac]

Now to incorporate that in to a shower so that "In the Year 2010" book I read as a kid in 1973 would finally come true...

[@ForwardEngineering]

Awesome stuff! Reminds me of old mercury rectifiers.

[@Conmega1]

Fantastic video! Although I hope you have a roughing pump with the right oil in it! Standard vacuum pump oil if pumping pure oxygen will turn your roughing pump into a BOMB!!! The correct oil costs a LOT more money than the standard oil so most roughing pumps will not contain it if you get them used. One of these oils that is safe is Fomblin. Please be careful pumping pure oxygen enviroments!

[@arthurharrison1345]

This is a great tutorial. Clear and informative!

[@toolhog10]

Your channel is ALWAYS interesting.

[@oddarneroll]

Wow! Thank you for making life intersesting!

[@pooyamz]

Hi Ben, Nice video, Your RF energy inspired me to make plasma with microwave owwn magnetron but I am pretty unsuccessful ! I tried building a very precise waveguide with horn antenna aimed to my vacuum bell jar and also tried to wrap 3 or 4 rounds of copper wire around bell jar with one side connected to magnetron antenna and other side is connected to ground but still nothing happened ! with my calculation Magnetron efficiency is around 60 ~ 65 % so the magnetron will make 2.45 GHz at 700 watts ( Input is around 1100 watts ) and when system is connected to my antenna setup ( 16 dBi horn + waveguide ) it will produce around 6000 watts of ERP which is very huge but still nothing happens ! I am really stuck and your help will be much appreciated. Thanks

[@sirislaursen6990]

Great video. What would I search for if I wanted to purchase an RF generator and network for a setup like this?

[@noakeswalker]

Old vid, new comment - plasma ashing like this is also wonderful for 'priming' surfaces ready for adhesives - you can glue very unlikely surfaces together after cleaning (as Ben says here) by normal methods first, then giving them a minute in a plasma asher, with oxygen, or oxygen and argon. Not sure what results you get with plain old air in the chamber - never tried this myself.

[@z3d12]

yay another awesome video. Your videos always make my day

[@sasjadevries]

I liked the video in advance, from the title i knew it would be interesting.

[@MrJonEvans]

Plasma treatment can also be a good way of modifying or hydroxylating surfaces for subsequent chemical functionalisation, useful when making e.g. sensors

[@keithnoneya]

Really cool idea, very well explained. Best Wishes n Blessings Keith

[@driverjamescopeland]

I would like to see the paper remnants tested, to see if there is a layer of nanocarbon graphene on the remaining cellulose. This could be a fairly efficient way to cultivating carbon on unidirectional cellulose media, if all the carbon isn't oxidized.

[@s28400]

Very, very cool video. Learn a lot every time. Keep it up!

[@Jawst]

This reminds me of a documentary I watched on British television!, I don't know if it's available online but inhaler aluminium canisters are also treated on the inside with plasma! The RF electrode is placed inside each canister it's very interesting and worth a look into!! KZbin video link ending kEdHi8r4828 has a basic description of the process

[@DidntKnowWhatToPut1]

Sounds useful for telescope mirrors.

[@stepandmitriyev5706]

Could you build a small particle accelerator and make hydride with it?

[@spinafire]

Amazing stuff. Thanks for sharing, I always learn a lot!

[@angeldeanda3573]

wow only 19 people disliked, im impressed. Keep up the content thanks!

[@Capslacka]

Could you predictably etch the surface of the glass using this method? Especially, could you etch certain locations and not others?

[@slydesplaylists]

uv does pass through air and makes things glow in the dark. a nice hand held three phase AC unit would be a nice product though.

[@GMCLabs]

whats the peak to peak voltage of the RF generator?

[@MathMeansMore]

Love your videos Ben, I'm a computatonal physics grad student so I never actually do anything in a lab, it's awesome to see someone with so much practical and hands-on knowledge! What do you do for a living?

[@kreynolds1123]

I wonder if one can use different coil geometries to inductivly push the plasma like a pulsed inductive thruster, except instead of pulsed power, it is fed continouse three phase power RF power to each of 3 coils physically roated 120 degrees from the other coils with the idea of creating a continuous linear induction plasma motor/pump/thruster. Presumably, the eddy currents in the plasma should push against the changing magnetic fields, and alternating the currents between three coils would create a traveling magnetic field down the length of the tube.

[@omsingharjit]

Plz make intro video on very low pressure discharge tube or vaccum tube ( 10^6mmhg) of xray project !!

[@faxezu]

Is it possible to get some problems with authorities cause of the transmission power or are there no "free" waves? I only know that we have in Germany a national instution that measure the Electromagnetic spectrum to find illegal transmitter.

[@MrJonEvans]

Look up ISM bands - 13.56 MHz is reserved for all kinds of RF kit like semiconductor deposition/etching systems

[@omsingharjit]

crazy Ques !!! but.. is there any way to make DIY Si Transistors or diode using Vacuum Deposition and Pure Silicone plates ????????

[@geraltofreviews6032]

Clear and concise. Thank you

[@ver64]

Interesting....thanks Ben .....and happy new year

[@Geogrn]

WOW , It's very thorough

[@proper1226]

+Ben Krasnow Could this be used to make beef jerky? Would be great to see the idea experimented with!

[@ajtronic]

Oh. This was fascinating to watch. Thanks

[@niuxx]

Ben, could you provide some details on how the impedance matching was done?

[@erikschiegg68]

You come with us. You repair our crashed space ship, earthling!

[@firstmkb]

Can you show the modifications you've made to your dishwasher? But seriously, what works well for baked-on oil on cookie sheets? Sodium hydroxide overnight was way too aggressive.

[@profesorfrink42]

Is there a power threshold for removing different types of material or is it dependant on exposure time? Basically, you've showed us you can remove dirt and other types of contaminants this way, but, could it also remove a conductive layer on a PCB? (for example) Great video, as always!

[@calebmcnevin]

Even the titles of your videos make me feel smarter ;P

[@kylehaley5433]

Kind of like your own corona treatment device. Always cool stuff around here.

[@svyl]

This sounds useful for cleaning sensitive optics. Would using the magnetron from a microwave oven instead of the RF generator work?

[@holaamigo3399]

there are metal parts in it wont the metal heat... wont it be more effective if there arent any conductive things

[@knikula]

cool , I'd forgotten we used Oxygen plasma cleaning . We also used pirani as a primary cleaner...that stuff was nasty, and effective for glass substrate cleaning

[@danheidel]

Ugh, pirani/pirahna. That stuff is scary.

[@knikula]

Dan Heidel I recall a power outage shutting down our ventilation system once, didn't take long to figure out how nasty pirani was...

[@msxcytb]

Impressive video! Thanks for making it. How would cleaning with (negative) Corona Discharge compare with plasma used here?

[@VKRenato]

Amazing! Thumbs Up.

[@hasansiddiqui1337]

great video, can you suggest me power supply for cleaning glass in vacuum chamber. my chamber size is 2000*2600 mm and vacuum can be reach to 3.5 E-3 Pa.

[@gh0stmast3r]

Ben Krasnow what is the fundamental difference between fire, the flame, and plasma? i thought that fire was a plasma that was created by the high heat of the reaction between the fuel and oxygen. i know there's a video on youtube that shows that fire has conductivity, it was shown in the best way, a dude fired a flame thrower at a tesla coil.A by that way of thinking though if i were to clean a slide using a fire it would have close to the same effect right? i'm assuming though that the oxidized fuel that's left over would contaminate the slide.

[@skycollection]

Have you made an experiment with an electrode of graphite and depositing graphene in the chystal plate...?

[@LarsBerntzon]

Nice video, I had not heard of this technique at all. Question, why use RF, couldnt you have used electric discharge inside the chamber instead?

[@DCFusor]

DC is harder to control, but is used by pros I know.

[@DanielHankewycz]

There's no risk in the oxygen combusting? Or does the vacuum somehow counteract that?

[@karthikbalaji8797]

great video. can anyone teach or post a videos about the steps to build one for our lab..thanks in advance..

[@horrorhotel1999]

I don't see why it would, but before I start tearing things apart, I tought I'd ask: Is the RF-frequency critical for this application? I'm thinking of replicating this system but I don't have a rf transmitter. However, I'm thinking about using the driver circuit from an ultrasonic cleaner, since it should have plenty of watts for this application and puts out 42kHz. Is it simply a matter of replacing the transducer with a couple of loops of sufficient awg wire, or am I overlooking something here?

[@themitchwich]

What would happen if you lifted the canister while it's cleaning?

[@waterandafter]

What would the effects be on cloth? Non-organic of course. Could this replace the chemicals used at dry cleaners?

[@cdyoutoob]

Is pulsed laser ablation something that is used in electronics to do spot/area cleaning. Plasma cleaning would seem like a full part immersion solution potential damaging fragile/sensitive components. Looking for solution to clean fingerprint oils and other common fod that does not use chemical cleaning like Acetone or IPA.

[@Mrnoth3m]

Can you recommend any books for understanding PVD (sputter and cathodic arc) and appications?

[@MajorHavoc214]

Great video, but I guess plasma cleaning would be a bit too much for cleaning the lenses on my glass eyeglasses.

[@wolfgangouille]

I think the surface becomes more hydrophilic after also because the surface becomes electrically charged (SiO-)

[@thrillscience]

Ben: Have you ever tried to make a vacuum tube? (A triode, for example.)

[@gillardscott]

Hello Ben I am fiddling with my own RF sputtering apparatus and would I get the same effect if I used the RF gun in the chamber instead of wrapping the coils around the bell jar? Or would i just be sputtering in the localized target area?

[@anarchangel7]

This is really cool. Not to turn you into the king of random or anything but it would be really interesting to see something larger and organic go through this process. Slice of banana or piece of meat. Ashed by plasma.

[@EDM713]

Hmm. Would this method of cleaning be good for say dish washing machines?

[@aarons3166]

Is there a term for the process you mentioned where molecules kinetically (via collision) remove contaminants?

[@harviecz]

What is the easiest way to build simple 5W RF generator for this use at home? Can i use mason jar and broken plasma ball or violet wand for this? :-)