Imaging CDs, DVDs or other optical media under SEM

In summary, the speaker is asking if anyone has suggestions for preparing CDs and DVDs for imaging with an SEM machine. They found a website that gave some hints, and after breaking the CD and imaging the polycarbonate surface, they obtained images with a track pitch that was half the expected value. They are wondering why this is the case.
  • #1
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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  • #2
Here is an idea of what you'll see

image027.JPG
 
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  • #3
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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  • #4
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?
 
  • #5
Track pitch is the full distance from one line center to another, not the width of those lines.
 

FAQ: Imaging CDs, DVDs or other optical media under SEM

1. How does SEM imaging of CDs and DVDs work?

SEM imaging of optical media involves using a focused beam of electrons to scan the surface of the disc. The electrons interact with the surface, producing signals that are used to create an image. This method allows for high-resolution imaging of the disc's topography and structure.

2. What type of information can be obtained from SEM imaging of optical media?

SEM imaging can provide information about the physical features and structure of the disc, such as the thickness of the layers, presence of defects, and surface roughness. It can also reveal information about the composition of the materials used in the disc.

3. Can SEM imaging damage the data on the disc?

No, SEM imaging does not affect the data on the disc. The electrons used in SEM imaging have a very low energy and do not have enough force to damage the data stored on the disc.

4. Are there any special precautions that need to be taken when imaging optical media under SEM?

Yes, it is important to handle the disc carefully and avoid touching the surface as much as possible to prevent contamination. The disc should also be placed on a conductive sample holder to prevent charging during imaging.

5. What are the potential applications of SEM imaging of optical media?

SEM imaging of optical media can be useful in quality control and failure analysis of discs in the manufacturing process. It can also aid in the development of new and improved disc technologies. Additionally, it can provide valuable information for forensic investigations involving optical media.

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