New procedures using copper liners for Innotec Users coming soon

Jeannie Perez nperez at stanford.edu
Tue Mar 30 13:58:46 PDT 2010


Please read all new changes coming to Innotec and Innotec Users.

Innotec Devotees,

 

You may have seen Jim and Jeannie testing a new hearth with copper 
crucibles.  They are working to solve the problems of the sources 
blowing up, being contaminated and the growth of residuals on the sides 
and bottom of the sources.  The feeling is the loss of good thermal 
contact between the source and hearth is the root cause of the source 
failures.  A common industry approach is to place the materials in 
crucibles instead of our approach where we remove and replace the source 
in the hearth with each use.  Source suppliers have tables showing what 
type of crucible is recommended for each material.   Jim and Jeannie 
have tried a number of these combinations without any success.  Instead 
of a source failure we were observing crucible failures. 

 

The concept of dedicating materials to its own crucible still makes a 
lot of sense.  This would prevent the degradation of the sources.  Jim 
came up with the idea of making the crucibles out of copper and 
machining the hearth to have a good fit and hence thermal contact to the 
hearth.  This is the configuration Jim and Jeannie have been testing.  
There goal is to release this to the lab member community. 

 

So far the testing has been going very well.  No offset between the 
crystal monitor and the deposited thickness has been observed.  This 
means if you continue to target 100nm on the crystal monitor you will 
get the same thickness on your sample.

 

One item which has been noted during the testing is the thermal transfer 
is much better with the new copper crucibles.  The source is cooled 
better which means you will need a little higher power than in the 
past.  Again, the crystal monitor will still tell you the correct 
deposition rate and film thickness.  On side effect of the higher power 
better cooling is a tendency to create a dimple at the beam location.  
To prevent drilling a deep hole in the source, the new recommended 
approach is to us the sweep function.  This will change your power 
settings, but the crystal monitor will give you the correct deposition 
rate and film thickness.

 

In summary these changes are being made to prolong the life of our 
sources, minimize contamination and prevent the explosion of sources all 
which result in a cost saving of materials.  This cost savings is not 
trivial as the cost of a new Pt starter source has crossed the $7,000 
line and gold is not far behind.

 

Once the conversion has taken place, please take the time to work with 
Jeannie on getting retrained on the new operating specifications.
_*Any questions or concerns, please contact staff; Jeannie Perez, 
Maurice Stevens, Jim Haydon, Ed Myers or Mary Tang.
*_


-------------- next part --------------
A non-text attachment was scrubbed...
Name: nperez.vcf
Type: text/x-vcard
Size: 346 bytes
Desc: not available
URL: <http://snf.stanford.edu/pipermail/innotec/attachments/20100330/de7d33c1/attachment.vcf>


More information about the innotec mailing list