Page History
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Flex cables/Panels back from BEI, 8/20/2018
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Overview
Short vertical flex cables. We suspect the 3 cables in the right bag passed electrical checks. The 6 cables on the right side of the left bag appear to be the cables identified as bad during the July 2018 BEI visit. There are 5 white slips, all face down, but on at least one you can read the word "Failed". We suspect the 5 cables on the left side failed electrical checks - it was noted during the July 2018 visit that there were some high resistance shorts that BEI was trying to address through a cleaning process. Electrical connectivity needs to be verified.
Photos of the long panels. Two panels were etched. The third panel was laminated but had no/minimal etching (there is a faint image of the circuit on the panel, which could either be photoresist or a very slight etch).
Side view of the HEMT region, showing severe buckling in this region of the panel
Closeup Photos Taken Using
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ppareg / B33 Wire Bonder Microscope
Photos of a delaminated trace that was deliberately bent over to allow view of underside of trace.
Another photo of delaminated traces
Photos of the transition between plated and unplated regions. Note the significant narrowing of the unplated traces. Some of the thinner unplated traces delaminated here.
More photos in regions near the plated / unplated transition.
Closeup of the narrow "chassis" trace, which had significant delamination in many cables. There appears to be no good reason for this trace being so narrow.
Miscellaneous Photos
Photos of wire bonder inspection setup
Paul's theory of what we are seeing
Closeup of unetched panel(?)
SEM Images: N1 Side 1 - 4K stage, HEMT
SEM samples taken 8/23/18 from panel labeled 'N' 8/22/2018
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Attempted to peel back one of the copper traces with tweezers and could see a thinner NbTi trace adhered to underside. From email by Jon: "the trace was adhered pretty strongly to the substrate."
N1 Side 1 - 4K stage, HEMT - Dispersive X-Ray Spectroscopy Data:
Site 1
Electron image:
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High reading for Beryllium?
Site 2
Electron Image:
Individual element images:
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Noise/Contamination?:
Site 3
Electron Image:
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Visible Structures:
Noise/Contamination?:
Site 4
Revisiting the lifted trace from N1 sample. The trace was gently bent flat to fully expose the underside:
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Beryllium image, see detailed spectrum below more more info on this reading:
Closer Look at Spectra:
Actual spectral line for Be is 100 eV (red line). Detector is "seeing events" with energies close to but not really that of Be (0-50 eV), so the software chooses to plot these as Be in above image. So this is probably just some sort of noise on detector, thermal, EM? In any event, EDX is known to be inaccurate for atoms lighter than Carbon. Edit: Reading through the data sheet for the X-ray detector (Oxford x-max^n 20) it claims that this is one of the few detectors that can resolve Beryllium accurately.
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Niobium and Titanium data also matched very well with expected spectral lines.
SEM Images: Sample : N2 - Side 1 (SQUID)
First images of N2 sample. Nothing really new to see on this sample, so EDX analysis will be skipped unless otherwise requested.
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Overview
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