hiding IC part numbers

Also triboelectric.

The links I gave you solve your problems even at the lowest wattage.

I also gave procedural (logistical) solutions. Like when to etch.

Did I mention that I used to have a job making authentication dongles? It was well before the (cheap) laser era, so we ground everything, printed or etched with a dremel. The makers used lasers then just not us regular folk. Now they are cheap.

While wet?

Do you think "wetness" automatically means a coupling to ground?

Hysol ONE C. White, gets to hard tack cure with a blast from a heat gun. Ceramic loaded epoxy, very low outgassing. Wont chip off, and anything tough enough to cut it will damage the chip. I know it says

Steve

Interesting. Thanks.

The conductive epoxy Ihave mentioned here in the past (Silver filled). is what they attach chip dies to the lead frame mounts and can lids in those cases. (ha! he said cases)

It would also aid shielding, not that it is an issue here.

Even faster at higher temps.

Similar appearance to those chips with silver coatings on top. Probably the same stuff, in fact.

Nymbecile > =A0 Also triboelectric

G > While wet?

Nymbecile > =A0Do you think "wetness" automatically means a coupling to ground?

Does the triboelectric effect take place under water, Dimmy?

It is not immersed, idiot, and nobody said anything about the wetting medium being water to start with.

And yes, regardless of how the electrons get freed, they would still accumulate. The triboelectric effect takes place because of the rub, not where the rub took place.

Learn how to quote properly, asswipe.

This is the grandaddy of chip photographers:

The logo is always on the die. I've never put a part number on the die. Usually you don't even know the part number until it is time to make the datasheet. Then the marketing person gets to make the executive decision and assign a part number, justifying their job.

I never saw paint and remark go through without a retest.

I would suggest a custom marking from the factory. A custom marking causes a bit of uneasiness since the company copying the product doesn't know if the part has special testing. Based on mask sequence, they can tell if the part has any different circuitry.

If the spec isn't in the electricals with test limits, it doesn't exist.

ot

From: Father Haskell Date: Wed, 4 Jul 2012 18:52:28 -0700 (PDT) Subject: Re: hiding IC part numbers

About a minute on a 600 grit diamond plate. Lap wet to keep the stone from clogging with slurry. One minute more on a 1200 plate gives a nice shine. Wet-dry paper would probably work, available in grits up to 3,000, considerably cheaper than diamond.

-------------------- To this you responded:

From: Chieftain of the Carpet Crawlers

Date: Wed, 04 Jul 2012 21:29:56 -0700 Subject: Re: hiding IC part numbers

Also triboelectric.

----------------------------------

I asked "While wet?" and you correctly pointed out that grounding would be an issue, but later you even suggested that the wetness might not even be water.

Are you REALLY so lacking in common sense that you think everybody else is too, Nymbecile?

Please explain how the triboelectric effect takes place underwater.

I've never heard of underwater static electricity. Is there an exotic form of water that is dielectric enough for that to take place?

Maybe some extremely demineralized distilled water? Norwegian heavy water?

You might try a UV cure epoxy or UV ink. Epoxy Technology says they can do color. Master Bond has a UV cure epoxy that cures with a "haze". This might be enough to obscure the part number. The problem with UV ink is amount you have to buy and shelf life vs limited amount you will probably use.

Call Epoxy Tech, Master Bond, Loctite or 3M. Another one is UVEXS in Sunnyvale

Ethics? What do you mean?

Nymbecile > You're a goddamned idiot,and you deserve no more of my attention.

Who else is on that list so far?

Ok.

There's a little bit of squiggle at the top. The edges could be sharper ("only" 72ps?). Rise and fall aren't matched to arbitrary precision. There's drool after the falling edge. The pulses are off timing by a few ps. Etc.

But what you're really after is, it could be a pile of junk, but if that's all the customer wants, then it doesn't matter what anyone else says about it. More specifically, even if it's not what the customer wants, as long as you sell it...

Tim

-- Deep Friar: a very philosophical monk. Website:

Is Nymbecile also StickThatUpMyASSAndSmokeit ?

Nothing is matched to arbitrary precision.

The output of this differential pulser challenges sampling oscilloscopes. PSPL has a series of appnotes about the response of various sampling heads.

The 20/80 rise time, which is what people generally use in the picosecond business, is around 42 ps.

As it turns out, customers want it.

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