K18R Liquid Crystal Utilization Notes |
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(.pdf 66KB / 1 page) |
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Introduction |
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K18R is a low viscosity solution of the popular K18 liquid crystal
dissolved in solvent. The clearing point of K18, 29°C, is close enough
to room temperature to detect many leakage sites without using external
heating. With external heating, defects dissipating as little as 10
microwatts can be precisely located.
The low viscosity solution readily wets IC surfaces and automatically
produces a very thin coating optimal for hot spot detection. |
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To apply K18R… |
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| 1. | Open vial of K18R. |
| 2. | Wet tip of nylon liner brush with a drop K18R. |
| 3. | Close vial. |
| 4. | Touch brush to surface of device under test. |
| 5. | Wait 30 to 60 seconds for solvent to dissipate. |
| 6. | Examine device in a microscope under cross polarized conditions. Areas coated with liquid crystal will be colorful due to the optical properties of liquid crystal. (This presumes temperature is less than 29°C.) Bare areas will be dark. Retouch as necessary to achieve complete coverage. |
| 7. | Return brush to storage tube. (No rinsing or cleaning is necessary.) |
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Observe device under cross polarized conditions. Bias sample to
leakage condition and scan IC surface for a dark (hot) spot within field
of bright, cooler liquid crystal. |
Note… |
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A pleasant variation is to view the device through cross polarized
conditions as liquid crystal is applied. The image is nearly black
as the liquid touches the device, then blossoms into color as the solvent
evaporates leaving a film of nematic phase liquid crystal across the surface. |
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For questions or comments about the technical content of this site, contact David Burgess: Email: davidburgess@AcceleratedAnalysis.com Phone: (650) 867-8443 or (650) 726-1832 Fax: (408) 241-0547 |
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