I'm terrified of ESD. Enlighten the newbie

[FlevasGR]

Hello guys, recently i started learning about ESD and after i red about what it can do im terrified. I'm mostly doing stuff with arduinos and atmega chips and i've never encountered any damage even when i was building my computer i did literally nothing to protect the hardware however the danger exists.
I would like to get few things straight in my head about ESD. Mostly protection, what is causing it, storing sensitive equipment, equipment i should buy for protection.


Protection and equipment

Currently im having only an antistatic wriststrap which im connecting on my computer's case. I know its not enought.
I'm thinking to buy an antistatic mat (if you have any suggestion from ebay)



Storing sensitive equipment

In this area i might have the worst storage boxes. They're some cheap plastic boxes with sockets. Again if you have anything to seggest please tell me.

[TimFox]

Some general statements, but you should consult textbooks for details.
1.  There is conductive plastic, which is usually used for the tubes that contain ICs from the vendor.
2.  There is also conductive foam thatcan hold leaded ICs and transistors.
3.  Most conductive packing material (bubble wrap, etc.) is colored pink for coding.
4.  If everything (your wrist strap, the box (unpowered) being worked on, etc.) is on a proper antistatic mat, you should be OK but see the manufacturer's information about how to connect mat and strap.

Many vendors only stock pink material and use it for everything.  When I received a dozen 1/4-20 UNC stainless steel bolts (approximately M6 for metric people) in a pink plastic bag, I shuddered to think of the ESD magnitude that could take out such an object.

[flynwill]

The risks are not that great.  I've almost never been bother with using a wrist strap or anti-static matte.  (But my normal workbench is wood on a metal frame so naturally anti-static).  Plastic boxes like you are using for storage are fine as long at the chips are in anti-static material, which is usually pink in color, but some vendors use black conductive foam, or the metalized (silvery) plastic bags.  If the foam in your pictures isn't the pink anti-static stuff (I can't tell for sure from your picture) an old trick is to just cover the foam with aluminum foil and then push the chip legs through the foil and into the foam.

If the weather is dry and you notice the sparks flying when you touch the doorknob then do ground yourself before handling parts.

There are a few parts, such as occasional mosfets without gate protection diodes, that are extremely sensitive and must be handled with great care (usually by keeping the leads all shorted together with a bit of wire until the device is safely installed in the circuit).

[tautech]

Hello guys, recently i started learning about ESD and after i red about what it can do im terrified.

IMO there's no need to be. The fact that you are now very aware and are taking basic precautions should be enough.
With basic knowledge, methodology is the key to mimimising risk.

what is causing it

Mostly friction, and the materials we use in our environment inability to conduct away that electrostatic charge so that all things are at the same potential.
Synthetic floor coverings have the worst reputation and charge us up like batteries.

A lecturer mate to demonstrate ESD, measured all students in his class and there were significant variations between them. Each of us is different....the clothes we wear, shoes, socks etc.

IMO the pink foam/bubble wrap is CRAP and I wouldn't trust it. 
All that I have measured are not conductive.
If I see a suppliers listing with pink packaging, I won't buy from them.

Show me a Pink product labeled as ESD safe and I'll reconsider.


The black foam, grey/silver antistatic bags etc. 
I'll trust that horrible foil covered polystyrene, but I don't like it.


So equalisation of static charge is the key, touch the Gnd'ed chassis, with the other hand pick up the container/tray/bag, extract the device and insert......If you need more hands to do this, use a wrist strap.

Population of a PCB should be done with basic care and static sensitive devices......last.

[SaabFAN]

I just put my foot/leg against the PC-case under my desk.
Handling all sorts of electronic devices for over 15 years now and never blew up one.

That being said, I also heard somebody did fry a Macbook by just touching it

[GoneTomorrow]

Some general statements, but you should consult textbooks for details.
1.  There is conductive plastic, which is usually used for the tubes that contain ICs from the vendor.
2.  There is also conductive foam thatcan hold leaded ICs and transistors.
3.  Most conductive packing material (bubble wrap, etc.) is colored pink for coding.
4.  If everything (your wrist strap, the box (unpowered) being worked on, etc.) is on a proper antistatic mat, you should be OK but see the manufacturer's information about how to connect mat and strap.

Many vendors only stock pink material and use it for everything.  When I received a dozen 1/4-20 UNC stainless steel bolts (approximately M6 for metric people) in a pink plastic bag, I shuddered to think of the ESD magnitude that could take out such an object.

The pink plastic is usually only static dissipative. For conductive plastics you want to look for the dark, metallic looking plastic that usually explicitly states "ESD Safe." Dave has a video on this:

[rdl]

my normal workbench is wood on a metal frame so naturally anti-static

I wouldn't put too much faith in that.

Handling all sorts of electronic devices for over 15 years now and never blew up one.

The damage can take a while before it becomes evident.

Dave has a video on this:

As I remember, that video does a good job of explaining the different types of ESD packaging.

The best way to store components is in the packaging the distributor sends them in. They will have been educated by the manufacturer on what is required. If you get stuff that is ESD sensitive from eBay or other non-mainstream sources then good luck.

[Psi]

How often do you feel static shocks in your location?
If once a day you should wear a antistatic strap
If once a month don't bother.
I probably feel a static shock every month or so

Most hobbyists don't wear any strap.

[suicidaleggroll]

"Think before you touch" will go a long way to prevent ESD problems.

I live in Boulder, CO.  I get a nasty shock literally every time I walk more than 10 feet.  I've made it a habit to touch the metal frame of a computer, the mounting screw of a nearby electrical outlet or light switch, or just lay my hands down on an ESD mat for a few seconds before grabbing any piece of electronics, and I have yet to fry anything.  I rarely wear an ESD wrist strap either.  If I'm working that close to an ESD mat that I don't mind being tethered to it, I'm probably in nearly constant contact with the ESD mat itself anyway, which makes the wrist strap redundant.

[Zero999]

IMO the pink foam/bubble wrap is CRAP and I wouldn't trust it. 
All that I have measured are not conductive.
If I see a suppliers listing with pink packaging, I won't buy from them.

Show me a Pink product labeled as ESD safe and I'll reconsider.

The black foam, grey/silver antistatic bags etc. 
I'll trust that horrible foil covered polystyrene, but I don't like it.

Pink foam is not supposed to be conductive but dissipative, meaning it won't charge up like most plastics can. It still has a lower resistance than ordinary plastic but it's in the G Ohm region so an ordinary meter won't be able to measure it. It's fine to put devices in, if they're already in a conductive medium.

The metallised (silver) and carbon loaded plastics are more conductive and have a typical resistance of a few K Ohm to 1 M Ohm. They're designed to short circuit all the pins on a device together.

In an ESD controlled work station the only materials allowed are static dissipative or conductive. Everything else, is prohibited, including ordinary plastic pens and plastic folders, even your clothes need to be covered with an anti-static suit and you have to change your shoes.

Resistances are typically what you'd measure if you stuck your meter probes into the material about 1cm apart.

[brabus]

My two cents:

I never had any issue with ESD, even without respecting basic precautions. Reworking boards, testing, all in a hurry: no problem whatsoever, at least in the short term.

But lately, I collected an impressive number of faults with WS2812 LEDs. Those are really, really, really sensitive. I managed to solve my issues (fingers crossed) by grounding everything on my bench wia 1M resistors, including the GND of the board I am working on, before soldering. And with "soldering" I mean soldering on the board, never touching the LED. If I don't do that, be sure to expect a failure in the first or the last LED of the chain, usually after a few hours of working.
I wonder if there is any I/O protection at all, in those devices.

[Howardlong]

The only time I wear an ESD strap is when I'm working on flight hardware, in the clean room, or I am presenting or teaching. Those latter two I only do because if I didn't I'd have people getting all anal about it and not concentrating on what I've come to talk about. On flight hardware and in the clean room it's as much psychological as anything else, it's part of a regime to take care in general.

I was working on a project a couple of months ago in Dubai and we had a visit from almost the entire Dubai and UAE governments, including the two top dudes, the ruler of Dubai as well as the President of the UAE. We had one of our engineering model satellites out demonstrating its stuff, and one cabinet minister came over and started prodding it, much to the chagrin of the poor young engineer I'd been working with! I looked from afar and maintained a wry smile.

Have I ever had a part fail where I could say it was due to ESD? Personally speaking, no. I have, however, had products returned to me where, for example, the USB peripheral has gone (protected, I might add, with external protection diodes). Whether this was ESD, or a bad host port, or a transient of some sort, I don't know, but it does happen very occasionally.

Do I take care with parts? Yes, they're generally kept storedin their reels/strips/tray until needed, and then inside metallised zip lock bags. Do I use an earthed ESD mat? Yes. Do I take care to earth myself and the board I'm working on to the ESD mat? Not particularly, but having the mat there means it's difficult for myself, the board and the irons not to be at the same potential. But the ESD strap only goes on occasionally.

[janoc]

I used to worry about ESD quite a bit too, but it isn't such a big deal. I don't use a strap at home, but have bought a nice large ESD mat thanks to one of the people on this forum and I tend to work barefoot, only wearing socks (I am not working on mains powered stuff!). That pretty much takes care of any ESD charge I may have accumulated.

Essentially, the only really really sensitive parts where you could fry them accidentally are various small signal or RF FETs, pretty much everything else has at least clamping diodes on each pin today. Also assembled boards are less sensitive to ESD, because the PCB traces will dissipate the charge to some degree if you manage to zap it while handling it.

For storing sensitive parts (FETs, CMOS devices, opamps with FET inputs, etc) - the various antistatic bags, foams and manufacturer's tubes were mentioned already, in a pinch you can also use aluminium foil - the one from your kitchen. Just wrap the parts in it or at least line the box compartment where you are going to put the parts with it. It is less practical than the foam and bags, but better than nothing.

[Zero999]

I tend to work barefoot, only wearing socks

You might change your mind about that after treading on a stray DIL component. lol

[f5r5e5d]

cotton socks will likely absorb enough sweat to be static dissipative - wool and synthetics can make triboelectric charge generation worse

higher humidity helps dissipate charge

human noticeable static discharge is kV - way more than can be tolerated by sensitive parts without built in protection (but nowadays op amps, most logic has protection on pins - probably only sensitive gate fet, RF/microwave parts would be unprotected by built in diodes)

[mrkev]

Only time i wear a ESD strap is when I'm working on something really expensive. It's not as big deal as it was few decades ago, when chips had literary zero input protection, even chips with ESD warning in datasheet have protection diodes now.
Of course, better safe than sorry and if you are working on something that can't be easily replaced or is for someone else, always use protection. And even something like wire around one foot with >1 meg resistor connected to radiator, PC case or something that is grounded works...

[rdl]

The seems to be a lot of incorrect assumptions about damage from ESD and how important protection from ESD damage actually is. The semiconductor industry hasn't spent billions of dollars just because they wanted some cool looking shiny metallic bags or because they had it laying around and there was nothing better to spend it on.

Just because a chip didn't "blow up" doesn't mean it wasn't damaged.

Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.

ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications

[ruffy91]

I became aware of ESD after i got shocks literally every few meters. A few weeks later I discovered why. I stopped using fabric softener. Fabric softener makes your clothes static dissipative. Second most important to me is the room humidity. Hold it to about 60% and you most probably wont experience ESD events.

[Mechatrommer]

i thought the same, dont worry much about esd (but i usually gnd myself just by touching any grounded metal if i think to handle sensitive material, better do than sorry) until someone here from arizona i think... he said they can pick up static just by thinking. checking his place weather statistics is so dry, less than 10% relative humidity i think, so that make sense. very less static dissipative there. so i dont know about finland i think it is your flag there... better gnd yourself if convenient, but wearing a wired wrist strap is not convenient i think. and we are barefooted in home/lab, fwiw...

[kingofkya]

The seems to be a lot of incorrect assumptions about damage from ESD and how important protection from ESD damage actually is. The semiconductor industry hasn't spent billions of dollars just because they wanted some cool looking shiny metallic bags or because they had it laying around and there was nothing better to spend it on.

Just because a chip didn't "blow up" doesn't mean it wasn't damaged.

Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.

ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications

Yeah agreed, its also a case of how much time  do you want to chase a "random problem" though your board. Ideal zero...



Anyways back to the original question an esd mat would be a good start. And toss that white Styrofoam your chips are in its not your friend.

The cheap solution is to store ics in the metallic esd bags and make sure the is no clear plastic or white styrofoam in there as that will just generate static in the esd bag. Another alternative is theses esd (Conductive plastic) drawers. http://www.globalindustrial.com/p/storage/cabinets/drawer/esd-black-drawer-cabinet-w-48-drawers-12-3-16w-x-7-1-16d-x-21-5-8h

Not sure where you are but an esd mat can be fairly cheap.(i have bought from this guy a few times)
http://www.ebay.com/usr/canvu0_0?_trksid=p2047675.l2559


But as far as atmegas there not very sensitive to static has some ESD protection built in but other chips or fets etc you interface to might be.



Also to preempt a myth just because you touch metal dosen't mean you can then touch anything. How do you know that ic is not sitting at a few killo volts above ground? Thats why you need the esd mat is will allow a slow discharge to earth/ground. Remember voltage is relative not an absolute measurement.

[Nerull]

If you don't worry about ESD, start a project involving mosfets. You may find yourself trying to find out why some percentage of your mosfets are spontaneously desoldering themselves. Afterward, you will worry about ESD.

They die if you look at them funny. A few tens of volts is enough to break down the gate insulator and that's a couple thousand volts before you start to feel shocks. You can generate more than 50V by moving your arm an inch to the left.

[Icchan]

We're just about to start a new project and since we were really small co-op before this, and the project is somewhat serious one i decided to take the plunge myself to ESD safety.

Due to the schedule requirements and small voltages that the chips run at, I've decided to make myself ESD safe workbench because I don't want to waste _any_ time messing around with a weird bug that's caused by and ESD that wasn't obvious.

So what I do? Get a proper bench with full metal chassis, preferably wooden tabletop (you can get those anti static ones, but they're shitty expensive), put on it an anti static mat to cover the whole thing, and add a post or two to the edge of the table for wrist straps.

Get rid of all basic plastics and other insulators that you economically can (part trays, bottles... pens is a little overkill) and be wary of using normal tape around the area... it creates huge amount of voltage when drawn.

If you're really worried, buy ESD safe chair and ESD safe floor mat, but in general they're little over kill.

Don't wear clothes made from artificial fibers. Cotton is quite good, it doesn't generate a lot of charge when moving unless it's really dry. And always touch the anti static mat or put on a wrist strap when you're coming back to the work bench, before touching anything else.

And if you need to take the device out of that area, put it in ESD shielding bag before leaving, and open it only when you arrive back to an ESD safe environment again.

The last one is a bit of a stretch and not practical in many cases, but that's how many of these "oops!" moments happen.

[Howardlong]

The seems to be a lot of incorrect assumptions about damage from ESD and how important protection from ESD damage actually is. The semiconductor industry hasn't spent billions of dollars just because they wanted some cool looking shiny metallic bags or because they had it laying around and there was nothing better to spend it on.

Just because a chip didn't "blow up" doesn't mean it wasn't damaged.

Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.

ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications

While there is indeed some truth in this, I think we need to try to understand where paranoia can slip in at the expense of looking at other environmental factors.

A few years ago I was getting about a 10% failure rate on a wireless device regarding RF sensitivity, in particular a MMIC. I eventually convinced myself this was ESD related, so I spent money and time on all the ESD gizmos like flooring, foot straps, etc. Did it make any difference? Nope. In the end it was the thermal profile during reflow, that particular device was a complete bitch to get soldered without degrading its performance.

By the way, if you do keep forgetting to put on your strap, say you're often called away from the desk, the ESD floor mat plus footwear method where you tuck a strap from your foot into your shoe is a handy way of resolving your forgetfulness.

[schopi68]

As a technican that has been trained in ESD already 30 years ago i am shattered a little bit about this thread.
Some things i want to mention after reading here:

- a visible or human noticeable esd event will occur with charges > 3,5 kV. Most times you will not feel or see that you or something surrounding you is charged. High humidity may lower the charge, but in many cases not to a secure level.

- take a look on some data sheets and you will see that many semiconductors are sensitive to ESD-Events. i.E. Typical General Purpose Transistors are in the ESD Human Body Model sensitivity Classification level of 3B (sensitivity if >8kV discharge), so the danger level here is really in the human noticeable esd event range. But when it becames integrated devices are becoming more sensitive. iE. the ordinary ua7805 Votage Regulator from TI is rated  as sensitive to ESD events > 3kV. LM340-N and LM78XX is rated with 2kV on the HBM. And this are "power components".
Conventional CMOS output buffers will have a failure Voltage (in the HBM) around or below 200V.

- often it is said that there are input protection diodes. Yes, they are common today. BUT - their primary intention is to protect agaist events in the assembled device. They are going to discharge via the ground or power rail. But in unassembled devices there is no ground or power connection. They may going to discharge through any other pin in the part.
Furthermore these input protection is not capable of dissipating a large amount of energy. An noticeable ESD event is able to blow out this diodes too.

- In most cases a ESD damage will not result in immediate failure of the device. It's performance may be degraded (changed part characteristics) or it will fail at a later time. This can last from hours to tenths of years. A microscopical analysis can show if the damage has been the result of ESD.

- In an industrial environment experts are assuming that at least 50% to 80% of device failures in the field are the result of ESD damage. Miniaturization will make the things worse. 50% were stated at the year 2000, rising to 80% in the future.

- Always keep in mind that every ESD-discharge is going from one capacitor (i.E. the human body) to another capacitor (device etc). So if the charge is low, the risk of damage is lowered. A human charged to 1 kV is much more likely to destroy some components that a small piece of foam at 1 kV. The Human Body Model is assuming a body capacity around 100-300 pF and 1,5 kOhm discharge resistance.

- Be aware of electrostatic induction / influence. If something is charged to a high voltage it is able to move the charge in surrounding parts without touching them. If such a part comes to touch another (grounded) part an ESD event will happen.

[rdl]

A few years ago I was getting about a 10% failure rate on a wireless device regarding RF sensitivity, in particular a MMIC. I eventually convinced myself this was ESD related, so I spent money and time on all the ESD gizmos like flooring, foot straps, etc. Did it make any difference? Nope. In the end it was the thermal profile during reflow, that particular device was a complete bitch to get soldered without degrading its performance.

Just think how much time you would have saved if you had used basic ESD protection in the first place.