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MLCC crack detection



MLCC crack detection | 3 September, 2004

Fine crack in multi-layer ceramic capacitor (MLCC) may not be detectable by capacitance check.Could anyone out there advise which is the most appropriate method to test/detect fine crack ?

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MLCC crack detection | 3 September, 2004

Hi Ken,

I know this doesn't help in the immediate timescale, but isn't avoidance the best form? can you trace the cracking to a process issue (Solder profile, shock damage, handling damage, probe/ATE damage)or a chip cap manufacturing fault?

I can't see any electrical tests working in the short term as the layers storing the charge are connected to the terminations - they may only be effected later as you get moisture ingress - which is too late. Have you tried UV?



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MLCC crack detection | 3 September, 2004

Rob's comments make sense.

Responding to your question: * Sometimes you can see a resistance change * Sometimes you can see a leakage change

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MLCC crack detection | 6 September, 2004

Thx for the replies. Acutally I am doing a process related study to see whether the process (pcb depanelling)can induce crack to an MLCC. After depanelling, I will do a thermal shock on the MLCC based on IEC 384-1, that is, five cycles of 30min at high and low temp each, then test for the capacitance change. Is dissipation factor and insulation resistance or dielectric strength a better parameter than solely test for capacitance?

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Simon UK


MLCC crack detection | 9 September, 2004

I used to make aircraft instrumentation for Boeing, Lockheed Martin, British Airways to name a few..

I had the exact same issue on 14 of our product lines with a MILSPEC-CECC 0805 Type part Manufacturer was Rohm.

Nearly every single board failed due to these devices (>65%), if one failed on the board i replaced all of them, and re-tested and thermally cycled them inline with our spec (-55/+80 Deg/C for 48hrs) this was a nightmare, especially when some cracks were not detected until several weeks later while flying installed on a jet over the Atlantic! Not good for the company or the pilots underwear.

I had to make this good in quick time, i created this project;-

1 Tested components from the reel - destructive, themal shock and cross-sectional analysis from a lab and produced a report, the sample showed that most of the components were already cracked before they began the testing!

2 Obtained new reel and different manufacturers batch, trialed them again as above - failed for the same reason.

3 Called Rohm Technical, was told its our processes! i told him to get a life and be onsite at the factory the next day or else.

4 He turned up, i presented the data and he took all but 60 secs for him to realise it was the parts, so i sent him packing with the info and the bogus reels for thier own analysis.

5 I got a report back from them (which is available off thier website, if you read it it blames everything but the component!) and he stated that they tested a sample from the reel and found no problems.

6 Could not change the part in the design due to incompability, banned the use of the parts for any new design and set our design engineers on the case.

7 To this day any part that is spec'd to be military or screened, i immediately ban from production - engineers are sometimes forced to us these parts, but tell them the issues from a manufacturing viewpoint and how much time THEY will spend hand placing devices and you might get them to select some other package.

Good Luck! Simon

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