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.

[@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.

[@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!

[@DJChesley]

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

[@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...

[@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.

[@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.

[@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

[@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!

[@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!

[@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.

[@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.

[@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.

[@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!

[@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.

[@darkobul1]

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

[@nickmartinblue]

I always love these videos.

[@kwinzman]

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

[@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...

[@AdelAlouani]

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

[@PaulRonquillo]

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

[@teshk6256]

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

[@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!

[@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.

[@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...

[@vk2zay]

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

[@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 !

[@GMCLabs]

whats the peak to peak voltage of the RF generator?

[@arthurharrison1345]

This is a great tutorial. Clear and informative!

[@clarencecherrone7914]

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

[@oddarneroll]

Wow! Thank you for making life intersesting!

[@skidmoremusictech528]

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

[@DidntKnowWhatToPut1]

Sounds useful for telescope mirrors.

[@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!

[@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.

[@z3d12]

yay another awesome video. Your videos always make my day

[@geraltofreviews6032]

Clear and concise. Thank you

[@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?

[@sasjadevries]

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

[@s28400]

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

[@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

[@angeldeanda3573]

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

[@spinafire]

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

[@stepandmitriyev5706]

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

[@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

[@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?

[@ajtronic]

Oh. This was fascinating to watch. Thanks

[@calebmcnevin]

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

[@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.

[@erikschiegg68]

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

[@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.

[@ver64]

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

[@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!

[@VKRenato]

Amazing! Thumbs Up.

[@themitchwich]

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

[@kylehaley5433]

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

[@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.

[@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.

[@holaamigo3399]

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

[@omsingharjit]

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

[@niuxx]

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

[@EDM713]

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

[@arsenymakarov6961]

Is there a plasma powered dishwasher machine sold anywhere?

[@kgeorge1967]

Can you clean a metal sample in this apparatus?

[@mnothem1]

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

[@bigredinfinity3126]

Would it attack rust (iron oxide as it would be great to clean rust of boats if you can do it on a commercial scale

[@arinasan247]

What about the slide that had the oil on it? What about your fingerprint?

[@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.

[@DanielHankewycz]

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

[@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!

[@nebish]

Oh wow, was this an ionizing or non-ionizing plasma? Is the rf generator the samething as a signal generator? I'm a layperson, where could I go to better understand this, I find it totally fascinating. Could I build something like this?

[@05stickman]

Yes and no. The RF Generator is for higher power whilst the Signal Generator would just give you a mW output.

[@kreynolds1123]

@@05stickmani may be wrong and if i am someone please tell me. But it might be more appropriate to describe the components as an RF signal generator (note not all signal generators can generate signals at radio frequencies) and an RF amplifyer that can amplify the current or the voltage or both components of a radio frequency signal. I suspect that with inductive coupled plasma like this, one needs to really amplify the current, and to ensure one gets maximum power transfer, one has to minimize standing waves with appropriate impedance matching.

[@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? :-)

[@banama1758]

interesting videos dont stop please :)

[@sdkulkarni240]

Sir, How about diy electron beam welder. Is it possible. It will be real blessing in diy applications. If not possible, at least let us have difficulties in it.

[@jeremyb2829]

Can you clean wood Can you clean mold? Is it like ozone machine..

[@billkratzer1]

etching on an atomic scale? starting with a layered substrate? can't magnetic fields give pinpoint bidirectional focusing like the slide with the photo-resist experienced?

[@mikejohnson9118]

Is that a MK1 non gridded source?

[@proper1226]

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

[@wolfgangouille]

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

[@singh0833]

Is it possible to use this Mechanism to clean dishes?

[@Admendment28]

your video's are awesome

[@aarons3166]

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

[@dillipkumamishra9466]

Please send me the procedure details how can I generate plasma.

[@the1cyrus]

How big is your bell jar and how can i get one?

[@imtotob]

Plasma water treatment in chile ur plasma unit i think can do it as well hope you can trty this also and give all the specs thanks

[@jack_is_bored5091]

Super neat.

[@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?

[@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.

[@BeamAndRugby]

You may want to discuss the potentially adverse health effects of unshielded RF and UV radiation, especially as you increase power. It would be relatively easy for someone who isn't familiar with the hazards to replicate your design and end up hurting themselves or others. I can't say exactly how hard you would have to push that coil before you start to worry about it, but like I said, it would be worth discussing.

[@JohnCenaVEVO]

So, if we apply this method of cleaning onto an organic body, it would just turn to ashes, what if we'd apply this on a human, would the skin take any damage from that since there are some organic elements in it though were mostly made out of water?

[@danheidel]

It would do an excellent job of burning your skin off so I wouldn't throw the soap out just yet.

[@bayadm]

Could you please test this chamber with a microwave source to generate a focussed plasma. You can put a magnetron inside the chamber (taken from an oven) and use an internal metalic wall (with a small perforations to allow you to see through) and contain the microwave radiation! It would be great if you can test this. Is this even feasible lol? Cheers

[@walterdennisclark]

Is the RF energy the same for induction heating of metal parts? What is the frequency? Could you easily put more RF power into the bell jar? Is there a reason you held it to only a few watts?

[@BlackWolf42-]

Ben, could you just use a frequency set length of wire (I'm guessing around 20 meters) for the antenna and forgo having to tune out so much reflected power?

[@TheHackZone5]

***** Watch out for those RFID cards :) i think Mifare cards work at the same frequency,i don't know would it affect them but it's a strange coincidence

[@Firecul]

TheHackZone5 I actually just looked this up to check, you are right. RFID and NFC both use this frequency band. might want to watch incase it blows one of the receivers if you have something using this near.

[@jaytarro1846]

+Walter Clark The components in a relatively small tuner used for amateur radio might be made of plastic components and not water cooled. They can easily get damaged by melting if too much power is put through them. Some of the industrial RF tuners have water cooling through the coils and capacitors and can withstand much higher powers. Plasma-Therm is a company that has been around many years and makes hefty RF generators and tuners.

[@xPROxSNIPExMW2xPOWER]

How much did this rig of yours cost to build?

[@diasyuri]

***** Sorry for insisting, but could you say a number just to have an ideia ? thanks

[@Invit123]

Vacuum setups can get really expensive. I think mine got to around 1000 with all that's in it.

[@GGG-xx8lf]

How did you seal the jar at the bottom? You can fit oring inside the glass?

[@ronaldo70004]

do you think it's possible to creat graphite sheets (microscopic sheets) with your technique? would be interesting to try!

[@zachell1991]

That's Freaking cool.

[@OnlyZxxOnly]

Thank you.

[@CheeseBon]

Amazing, i love your channel! Ben, whats your educational background? sorry you've probably been asked this a thousand times.,

[@sweetguy19762]

***** do I need a magnetron to cook something, or could I do it with a high wattage transmitter and an antenna?