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ICs are typically packaged (encapsulated) in a black "plastic". What is this packaging material made of?

enter image description here(source)

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up vote 22 down vote accepted

Transfer-molded epoxy (which is a thermoset material).

Thermoset plastics, once cross-linked will not melt, they only char at high temperatures.

See, for example, this TI/NS document:

enter image description here

As mentioned in the NS document above, epoxy cresol novolac (ECN) is the most common ingredient of these epoxies.

enter image description here(source)

Link to fire at Sumitomo in Japan in '93.

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What kind of epoxy exactly? There are many types of epoxy resins. – Sparkler Feb 15 at 22:21
It's quite specialized, in fact IC production was significantly affected world-wide some years ago due to a fire at a single chemical plant in Japan (Sumitomo). See the above link. – Spehro Pefhany Feb 15 at 22:23
So this "black plastic" is actually an epoxy filled with additional materials..? In that case, what epoxy exactly is the main ingredient of this "support matrix"? – Sparkler Feb 15 at 22:30
There is no one type of epoxy. It's a variety of chemical formulas that exhibit desired strength, color, thermo properties. – Passerby Feb 15 at 22:36
Almost all commercial resins (of all kinds) have additives as the NS document indicates. The exact formulas of the resin will be proprietary to the suppliers. – Spehro Pefhany Feb 15 at 22:49

Just to add to Spehro's answer, you can usually request the materials composition of a specific IC directly from the manufacturer, if you know where to look. They won't give away the complete recipie for how to build trade secret products, but they will be able to tell you the general chemical composition of the final product.

Just did a quick check through a couple of IC manufacturers familiar to me, and found these links:

Note: these links could be subject to "link rot" as manufacturers redesign their websites, but usually this information is offered under a Support or Quality & Reliability menu. Key terms to look for are Support, Quality & Reliability, RoHS, Materials. Worst-case you can directly contact someone at the company's applications or customer service department, they should be able to tell you.

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Good point. Looking at Maxim's data for the MAX232 leads to this Sumitomo data. Pretty sketchy, but better than nothing. – Spehro Pefhany Feb 16 at 4:10

One other important feature of the material is its opacity.

Any light that makes in through the housing to the chip may cause it to malfunction. Transistors and other active components are light sensitive, so any light will make them operate incorrectly.

I once worked with a guy from the DDR (GDR or East Germany,) who had a lot of experience with products of the DDR and the USSR. He told me that he had a soviet produced pocket calculator that wouldn't work outdoors - the sunlight leaking through calculator housing and the chip package would cause the processor in the calculator to lock up. If the light wasn't quite that strong, it would just sometimes give a wrong answer. He claimed that this was a common problem with soviet produced chips. The impression I got was that they bought packaging material (from ouside the USSR) to use for important stuff and used "home grown" packaging material for consumer products. Andre compared the "home grown" packaging to dog turds - it was some kind of off brown color and did a shitty job as a packaging material.

This doesn't answer the question as such, but it was too long for a comment and provides a little more background on what goes into the package material.

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Old, germanium diodes and transistors were packaged in glass which was covered with paint. Scrapping off the paint was a common way to get a photodiode. – Agent_L Feb 16 at 14:42
@RossRidge: Yeah. GDR. I'll change that. – JRE Feb 17 at 7:52

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