Imaging CDs, DVDs or other optical media under SEM

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SUMMARY

This discussion focuses on imaging CDs and DVDs using Scanning Electron Microscopy (SEM). The user shares their experience with imaging CD-Rs, noting the need for careful preparation, particularly with the aluminum layer and polycarbonate surface. They observed that the track pitch measured was approximately half of the expected value of 0.8μm. The conversation highlights the importance of understanding the layered structure of optical media for effective SEM imaging.

PREREQUISITES
  • Understanding of Scanning Electron Microscopy (SEM) techniques
  • Knowledge of optical media structure, specifically CDs and DVDs
  • Familiarity with sample preparation methods for SEM imaging
  • Experience with measuring track pitch in optical media
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  • Research sample preparation techniques for imaging CD-Rs and CD-ROMs using SEM
  • Learn about the layered structure of optical media and its impact on imaging
  • Investigate methods to accurately measure track pitch in optical media
  • Explore advanced SEM imaging techniques for enhanced resolution
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Researchers, materials scientists, and technicians involved in imaging and analyzing optical media using SEM techniques.

Septim
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Greetings,

After getting some training I have access to my universities SEM facilities and I would like to image CDs and DVDs with it(, I know that these consist of many layer which may not be transparent to the e-beam so they might need some preparation. Does anyone have any idea? I am reluctant since I could not exactly figure out what kind of preparation is required for say CD-Rs CD-RWs or directly CD-ROMs. Any suggestions and help is appreciated.

P.S : I found this particular website which might give you a hint about the kind of preparation involved.
 
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Here is an idea of what you'll see

image027.JPG
 
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Actually I got the following images where the track pitch is nearly the half of the value indicated on the web and your post (0.8μm ). In order to image the CD-R(Not a CD-ROM), first I broke it carefully then I proceed with the aluminium layer just under the label which did not give much of an image and later I decided give the polycarbonate surface a go and got the resulting images at different magnifications.

CD23.jpg
CD24.jpg
CD25.jpg
 
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Septim said:
Actually I got the following images where the track pitch is nearly the half of the value indicated on the web and your post (0.8μm ). In order to image the CD-R(Not a CD-ROM), first I broke it carefully then I proceed with the aluminium layer just under the label which did not give much of an image and later I decided give the polycarbonate surface a go and got the resulting images in different magnifications.

View attachment 77663 View attachment 77664 View attachment 77665
You have any idea why the track pitch was half of the value it should be?
 
Track pitch is the full distance from one line center to another, not the width of those lines.
 

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