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Old 10th November 2006, 10:59 AM   #21
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Default transistor (dies )

Hay. Gentlemen:
Thank You for interest on the point Wafer, Actually if the transistor still in die form, it cannot be tested.

If test should be excised, first cut out the die from it's wafer, then bond on the tr. packing, then ultrasonic bond out the leads,
in production line, if necessary, they will do this, but this would cost time and money, usually they wouldn't go this way.

Usually the rejected wafer is rejected by visual, such as scratched,
photo etching not perfect, like cannot define out the patent, or broken wafer during handling. If a wafer more than 40% fail, then rejected.

Another fall out is when the transistor was packed from die, after bonding, casing, then go for test before marking. If the lot more than ???% of failure, ???depends on individual manufacturer, test include Beta, Vceo, Vces, Ic, Hie, Hoe--------- total 33 tests. then if the lot does not meet the yield rate, then the lot to be rejected without marking. Then the Fake people do their marking.

From the above points, Fake, copy, false---- transistor were selled on the market.



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Old 10th November 2006, 11:22 AM   #22
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Quote:
then the lot to be rejected without marking. Then the Fake people do their marking.
This seems not to be the case so far, all the fakes i found had much smaller die then the orginal.

I can also not image that Onsemi for example would sell rejected lots knowing that they would be used for fraud.
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Old 10th November 2006, 12:51 PM   #23
anatech is offline anatech  Canada
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Hi sayang001,
From what I've heard, rejects are destroyed for that exact reason. Also the lot can be written off as a loss as long as there is reasonable proof it was destroyed. I wonder if they melt and recycle the silicon?

The chips can have some tests done by probing also, they do not need to be mounted for some basic tests.

-Chris
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Old 10th November 2006, 12:54 PM   #24
clem_o is offline clem_o  Philippines
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Default Re: transistor (dies )

Quote:
Originally posted by mitwrong
Actually if the transistor still in die form, it cannot be tested.
Hi mitwrong,

This might be the practice for transistors, but with LSI (i.e microprocessors and related support peripherals), die is tested prior to wafer cut, with at least gross functionality test.

I'd like to state that regardless however, I'm very grateful the information you are providing!!

Cheers!
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Old 11th November 2006, 07:08 AM   #25
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Default Transistor

Hay, Gents:

From the begining to now, I still taking about transistor, Not LSI or other products.
For the flake products, the original manufacturer they only sell out the scratched die or unmarked semi at the back door, After all, nothing to do with him.

Onsemi has his own wafer produced, no point he will do the fakes.

I mean the third party, somewhere underground, they bought the fall out product, then do their packaging and marked on the rejected stuff. Usually this happened in Asia somewhere, I know, but it's not convient to say in open area.

Sometimes, they also marked manufacturer like Moxxxxxx, Faxxxxx, Sxxxxxxx, Txxxxxxx-----, they marked the same as the orgs. about the die size, that is, U can think about a large manufacturer firm will not change the size of the die, if they want to change the die size, they will change the part number and become another product. Only the fake people they bought these mixed up stuff with a very low price and also doesn't want to change the marking system setup, therefore U guys buy the fake product without knowing what it is. Of cause, basic function like N or P type, Meter test passed. Also everybody know this is fraud manner, but money is bigger than anything. also nobody knows where they are, they just like an ordinally supplier provide the stuff to the market.

Anyway, I am not the one seen this case, believe or not, is your choice,
I am telling the truth. on this open area, I can't talk in details, if someone experienced this type of case, he will know I am telling the truth. this happened in one underdevelopment country.

Not only transistors, Vaccuum tube ( valve ), today they have good market price, they bought the one produced in an underdeveloped country and marked with Gxx, Muxxx, Texxxx brand names. (note xxxx is just represents the rest of that name with not exact number of alphabet. These Brands are no longer produce valves, but today, fresh from production with fresh marking. valve type like ELxx, 6Cxx---, they sell them on net.





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Old 11th November 2006, 07:19 AM   #26
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Default A word on IC

Hey, Gents:

Another proof on fake product is a part no TDA2030 marked with TDA2040, then they sell at TDA2040 price.

If someone bought one of this IC and burnt, can U find out the reason on it.




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Old 11th November 2006, 08:01 AM   #27
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Default Post25 correction

correction:
I am talking about transistors
I am not the only one seen this case




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Old 11th November 2006, 05:10 PM   #28
PB2 is offline PB2  United States
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Default Re: My Transistors, original or copy?

Hi Chris,

First. I thought I'd mention that I worked on the design side for a major semiconductor company, but had little to do with the fab side.

I'm currently doing robotics and machine vision work for a company who is also concerned with these component issues.

I thought I'd mention the idea for the case where there's a large lot of parts, of opening the can on a few samples of say metal can parts to inspect the die. I'm not certain that lot codes and date codes are on the die, can anyone confirm this?

I believe that manufacturer's keep date codes and lot codes on file so that fall outs can be identified if they somehow make it to the field.

Pete B.


Quote:
Originally posted by anatech
This thread intended to be an information resource for all. Please post measured data and photos for complimentary pairs in one post. The data will be condensed so we have a single post for each type to make things easy to look up. It will be a sticky.

I would like to thank MikeB for encouraging the creation of this resource, and all the members who have collected and posted information previously. Also the members who post new data. We will condense new information into a pre-existing post for the type number. All O.T. posts will be removed to keep this thread clean and useful.

My hope is that this thread will assist members in their semiconductor purchases. Another thread on this can be found here.

-Chris
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Old 11th November 2006, 08:04 PM   #29
anatech is offline anatech  Canada
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Hi Pete,
Good idea for incoming inspection. The best defence is to only buy from a traceable supplier. If you do that the chances of getting caught with fakes are greatly reduced. That was the purpose of this thread. The parts I've posted come from a known supply chain. The On Semi parts were On Semi samples, directly from On Semi. This was the only way to guarantie the measurements and pictures. This is in hopes to allow our members from other countries with longer supply chains a chance at identifing fake parts.

The only thing I can say too is that if the price is too low, there is something wrong. Either stolen, rejected or outright copies of parts. Don't feed that market.

-Chris
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Old 11th November 2006, 08:27 PM   #30
MikeB is offline MikeB  Germany
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Quote:
Originally posted by anatech
The only thing I can say too is that if the price is too low, there is something wrong. Either stolen, rejected or outright copies of parts. Don't feed that market.

-Chris
Chris, perfect words ! This should be shown as greeting text when entering this forum...

Mike
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