[SOLVED] how to remove chip name on chip case-body

[tpetar]

Hi,

How to remove chip name marked on chip body on top. I mean what is best and easiest way?

Purpose of this is to make harden identification of IC and uC.
Of course I use code protection on uC as additional measures.

I try physical scratching of chip surface with file, but on some chips ok (marks near surface-not deep), but on some others name is deeply engraved in body.

Is there some chemical way ?

I will try next with super glue, he make changes on some plastics.

 

[ZASto]

Why are you trying to waste your time to useless things?

EVERYTHING can be reverse engineered, even IC's with scratched markings. If you observe where comes the power to uC, it's quite easy to guess the type (difference between Atmel and PIC are quite obvious, and for logic IC's it's easy to trace inputs and outputs and to figure out whic IC it is.

BTW, for uC's, there are couple of companies that are OPENING the controllers , resetting the write protection and reading them out. FYI on every uC die, there's a chip type etched on.

 

[tpetar]

Why are you trying to waste your time to useless things?

EVERYTHING can be reverse engineered, even IC's with scratched markings. If you observe where comes the power to uC, it's quite easy to guess the type (difference between Atmel and PIC are quite obvious, and for logic IC's it's easy to trace inputs and outputs and to figure out whic IC it is.

BTW, for uC's, there are couple of companies that are OPENING the controllers , resetting the write protection and reading them out. FYI on every uC die, there's a chip type etched on.

I know what You say, but only Gods knows all and everything, and others knows somethings.
There are many people out, not all pro or they have time to make reverse engineering.
I know that this is possible if some people devote time to this, but they must spend some time on this and for what cost of doing this. For amaters this is harder to do this and they often have only unimer and soldering station or soldering iron direct on 220V, but no oscilloscope or such more expensive things.

I know for resetting flags of code reading protection possibility. Even for pro this is science ficture and only on movies, only if this pro have lots of money for some special equipments (I mean for opening uC and resetting code protection flag for reading). I found on Internet few companies that works this but, price is :shock:. I dont think that is worth for someone to deal with this and pay :shock:.

But i only want to prevent novice, amaters, pro without free times, and like that peoples from doing this.
Always exist way for opening every lock without key, but this is not reason to leave door open (that eliminate most of people to try this).

 

[ZASto]

Designs are copied by people who can find some economic interest in selling someoneelses design as their own. It is quite enough to set Code Protection bit in your uC. Mine designs were not copied, yet.

Novices are crying all over this board for PCB designs, HEX files etc. They will never read out your uC. Much easier is to figure out the rest of TTL chips.

 

[bigdogguru]

If your intent is making it difficult for an individual to reverse engineer your design, there maybe another option.

Depending on the size of the PCB and the thermal requirements of various components in your design, you maybe able to encapsulate the whole PCB in a potting compound.

**broken link removed**



3M™ Scotch-Weld™ Black Epoxy Potting Compound

**broken link removed**


One advantage to this technique is the PCB is now weather and water resistant. No technique is perfect or impregnable, however I can testify from personal experience that removing a PCB from potting compound is a non-trivial affair and requires many laborious hours of effort.

BigDog

 

[tpetar]

If your intent is making it difficult for an individual to reverse engineer your design, there maybe another option.

Depending on the size of the PCB and the thermal requirements of various components in your design, you maybe able to encapsulate the whole PCB in a potting compound.



3M™ Scotch-Weld™ Black Epoxy Potting Compound

**broken link removed**


One advantage to this technique is the PCB is now weather and water resistant. No technique is perfect or impregnable, however I can testify from personal experience that removing a PCB from potting compound is a non-trivial affair and requires many laborious hours of effort.

BigDog

Not bad at all. Only final weight of product is on question. But I like this.

 

[bigdogguru]

I once had to remove the potting compound from only the solder side alone of a potted PCB, it took several days of serious effort on my part. Removing it from the component side would be almost unimaginable. If someone manages to remove the potting compound from the component side of the board, I seriously doubt they will be able to identify any ICs from their markings and I almost guarantee the device will not longer function.

And I might also add, I plan on never doing it again.

BigDog

 

[ZASto]

Removing potting compound, if you have a suitable heat source aka oven, is less laborious.

Been there, done that.

 

[tpetar]

Maybe new generation of protection of device PCB and components is self destruct when someone try to open case like money with non washing paint during transport.

In this case like this epoxy with uC like watchdog. When temp raises at some predefined level (example 100C) uC make short circuit of some chips or send some higher voltage to them to destroy and disable them.
This uC only have this purpose to destroy main uC!
In any case You see epoxy is damaged and waranty for device is not longer valid!

 

[ZASto]

You must be kidding :smile:

When not powered you can not send any "higher voltages" to some chips to destroy them. There are NO voltages, Switched OFF :smile:

 

[tpetar]

You must be kidding :smile:

When not powered you can not send any "higher voltages" to some chips to destroy them. There are NO voltages, Switched OFF :smile:

Of course I kidding but when I look closer not so bad idea, puting few batteries inside.
I make mistake last week I put 12V to 89S52 in programmer. uC lost ID tag now is S53. Programmer see it like S53 but not working when try reading or writing, only erase working.

 

[bigdogguru]

Removing potting compound, if you have a suitable heat source aka oven, is less laborious.

The effectiveness of an oven depends largely on the potting compound. The potting compound I had the pleasure to remove, was mil standard, flame resistant and could withstand prolonged exposure to temperatures greater than 1500°F, so using an oven was not an option.

BigDog

 

[tpetar]

Interesting blog about extracting MC13224 firmware :
Travis Goodspeed's Blog: Practical MC13224 Firmware Extraction

 

[bigdogguru]

Interesting blog about extracting MC13224 firmware...

As I mentioned in a previous posting, no technique is perfect nor impregnable. If you have the resources, almost anything is possible. I have seen some very sophisticated safeguards used in some of the projects that I've been contracted.

However, in the real world you need to decide how much effort and money you are willing to spend to protect your design.

BigDog

 

[tpetar]

Of course this is on first place price of this and purpose.
I think that epoxy is right and good for my needs.
For me easyest way is to use epoxy (You give me nice suggestion - Thanks).
Also with this I get water and humidity resistance.

My target is protection from amaters and novice to keep them away from design and firmware.
For protection against Pro I keep praying.

 

[bigdogguru]

Yes, it appears a potting compound would be a good option for your situation.

The range of available compounds and their characteristics are wide ranging. The links I posted above include some of the more economical varieties.

There are even potting compounds which range from a ceramic, similar to the Space Shuttle tiles and can withstand temperature over 3000°F to incredibly hard metallic versions.

Of course, these more exotic varieties often come with a more exotic price tag as well.

BigDog

 

[tpetar]

Today some manufacturer of mobile telephones uses some epoxy (I supose its a secret formula), for their products. Samsung Galaxy S2 (mobile of year) have on rear cover made from some elastic epoxy. People asking why this plastic? why not metal (nickled,chromed,...silvered,golded,..) and get official answer: better cooling and better mechanical stress resistance.

 

[jpanhalt]

You asked earlier about chemical ways. Nitric acid will etch epoxies and leave metal parts relatively unaffected compared to other acids. It does not have the residual corrosive effects of sulfuric or hydrochloric acids. That said, I would use abrasive methods, like a belt sander.

John

 

[tpetar]

I think about that earlier (nitric acid), thanks for remind me, I whach this on net but I didnt try. I go to try now, I will find some victim in some older analog 40.. or 74.. chip. But I observed that there are differences between different manufacturers. Some grave marks with laser (I supose that is laser) deeply in epoxy body of chip and some manufacturer just a little under surface.

On net I found pictures of chinese replicas of transistors, microcontrollers and I shocked. Difference in typing letters positions, bold letters, are obvious. Picture inside when transistor opened, showing smaller N and P layers in replicas (smaller current, heating faster, ...). Replica uC have smaller core, not all features supported, error on some pins, not working at all (complete catastrophe) and typing letters on replicas are better watchable then on original.

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For me best way is to use EPOXY MASS !!!

 

[Raza]

Even when the voltage source is removed still there is a possibility to produce voltage on the PC board it self by integrating the hot wire Voltage generator. And on some components (specially on µC) a few millivolts are sufficient to destroy it.