How do manufacturers temperature grade their parts? - Page 1
Forum section: electronics / beginners

author: JoeN
author_rank: Frequent Contributor
timestamp: October 08, 2015, 04:33:19 am
content: Always wondered this and haven't asked yet. But what do manufacturers do to make an IC in two or more temperature grades? Is that an actual difference in process or are they somehow graded after the die is complete and before packaging, or after packaging? How do they go about that? Thank you.

author: JoeB83
author_rank: Regular Contributor
timestamp: October 08, 2015, 04:58:44 am
content: It's my experience and understanding that gradings are assigned after production, i.e. after testing. From what I gather (at least with manufacturers I've worked with) the components are tested after production, at varying degrees of difficulty, and those parts that pass all tests are grade "A", those that pass some "B", those that pass the bare minimum "C", and the rest are usually 'acquired' by others and sold on eBay, aliexpress, etc.EDIT: Were you curious about a particular manufacturer, or just the process in general?

author: JoeN
author_rank: Frequent Contributor
timestamp: October 08, 2015, 05:09:33 am
content: No, just in general. If there is a standout IC or manufacturer that does it differently because it is necessary for that IC or for some corporate reason, I would love to hear about it. That's sort of what I figured. I mean, the part has to work correctly and at at least the minimum specs at the minimum temperature grade, but different parts may stay within the defined "worst case" specs at different temperatures and I would assume those are how they are binned. If they don't even meet the worst case spec sheet definitions I assume all good manufacturers dump the dies at the earliest point possible in the assembly process and most of them don't even make it onto a lead frame.

author: rs20
author_rank: Super Contributor
timestamp: October 08, 2015, 05:41:18 am
content: Quote from: JoeB83 on October 08, 2015, 04:58:44 amDo you know this to be true with respect totemperaturegrading? I.e., military vs commercial temperature range parts?I would have presumed that they wouldn't go to the bother of testing most devices at temperature, and that the difference would be down to different material choices throughout the construction of the part.

author: JoeN
author_rank: Frequent Contributor
timestamp: October 08, 2015, 06:07:35 am
content: Quote from: rs20 on October 08, 2015, 05:41:18 amThat is, in a sense, why I am asking. Is it material or binning, or does it vary for different kinds of parts? I sort of assumed it was binning. A different fork in manufacturing, especially at the wafer level, I would guess really increases costs. I can't visually see any change in the packaging for most parts I have seen in multiple temperature grades except for the ones that actually get put into a ceramic package. Linear, as an example, has three grades for a lot of their parts and the packages all look the same to me.

author: rs20
author_rank: Super Contributor
timestamp: October 08, 2015, 06:13:16 am
content: Of course, the third possibility is that the parts are actually completely identical.

author: katzohki
author_rank: Frequent Contributor
timestamp: October 08, 2015, 02:50:09 pm
content: Quote from: rs20 on October 08, 2015, 06:13:16 amYep. I have experience with that. Parts are 100% the same and extra is charged for higher temp model. The justification (as explained to me by marketing) is that the extra cost covers "insurance" of having to guarantee the part at a high temperature range. This wasn't exactly an IC, but something more complex. Most manufacturers won't own up to that though, and if you try to use the low-temp part outside its range then you're SOL if it breaks.I've been a little frustrated by Maxim Integrated's temperature specs, so I wonder sometimes if they have something similar going on.

author: krivx
author_rank: Frequent Contributor
timestamp: October 08, 2015, 02:56:28 pm
content: Quote from: katzohki on October 08, 2015, 02:50:09 pmThis isn't always true, sometimes the parts are the same (i.e. same materials and same process) but only some are actually tested under controlled temperatures. You are paying for an additional test, but it is for verification and not for binning. I would put it as "all of our parts probably meet the spec, but you'll need to pay us to check"

author: edavid
author_rank: Super Contributor
timestamp: October 08, 2015, 03:23:51 pm
content: Quote from: JoeN on October 08, 2015, 04:33:19 amOnly the packaging and test program are different.

author: AF6LJ
author_rank: Unknown
timestamp: October 08, 2015, 03:29:47 pm
content: A company I use to work for (back in 1980) for a short time would take the Grade A parts and burn them in at high temperature with the junctions reverse biased. After a hundred hours or so of this the parts were re-tested and the good ones went on to the next test if there was to be one, often a leak test was incorporated ether before HTRB or after or both.Storage temp tests would be verified on selected parts at the customer's request.

author: katzohki
author_rank: Frequent Contributor
timestamp: October 08, 2015, 03:39:21 pm
content: Quote from: krivx on October 08, 2015, 02:56:28 pmI didn't say it was always true, but the technique you mention is also something I've seen.