Difference between revisions of "Photolithography - Improving Adhesion Photoresist Adhesion"

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(added Underlayers for PR adhesion)
 
(→‎HMDS Process for PR Improving Adhesion: dehydration/O2 pasma midifcation)
 
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Don't forget that, for [[Lithography Recipes#Lift-Off Recipes|lift-off processes]], the Imaging (top) Photoresist will lift-off as well if you undercut it too much during develop!
== Underlayers for improving PR adhesion ==
 
  +
 
==Underlayers for improving PR adhesion==
 
High-temperature (>150°C) underlayers, such as LOL1000/2000, BARC layers tend to improve adhesion of the imaging resist.
 
High-temperature (>150°C) underlayers, such as LOL1000/2000, BARC layers tend to improve adhesion of the imaging resist.
   
* Substrate prep: O2 plasma ([[Ashers (Technics PEII)|PEii Technics]]), 10sec
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*Substrate prep: O2 plasma ([[Ashers (Technics PEII)|PEii Technics]]), 10sec
* Apply high-temp underlayer, eg. LOL1000/2000, PMGI, DSK101 (DUV), DSK42P (DUV)
+
*Apply high-temp underlayer, eg. LOL1000/2000, PMGI, DSK101 (DUV), DSK42P (DUV)
** Beware of underlayers that have a develop-rate - undercutting the imaging PR fully can also cause delamination)
+
**Beware of underlayers that have a develop-rate - undercutting the imaging PR fully can also cause delamination)
* Apply your Imaging photoresist as normal.
+
*Apply your Imaging photoresist as normal.
   
== HMDS Process for PR Improving Adhesion ==
+
==HMDS Process for PR Improving Adhesion==
 
This process tends to improve adhesion between the substrate and subsequent photoresist layers. Use this procedure if you are finding poor adhesion (resist delaminating during develop etc.), or for chemicals (like BHF) that attack the PR adhesion interface strongly.
 
This process tends to improve adhesion between the substrate and subsequent photoresist layers. Use this procedure if you are finding poor adhesion (resist delaminating during develop etc.), or for chemicals (like BHF) that attack the PR adhesion interface strongly.
   
  +
*150°C bake ~2min (Dehydration step)
* O2 plasma ([[Ashers (Technics PEII)|PEii Technics]]), 10sec
 
  +
**Optionally could instead do Dehydration of: O2 plasma ([[Ashers (Technics PEII)|PEii Technics]]), 10sec; however this could create more surface SiO2 on silicon.
** This takes the place of the dehydration bake.
 
 
*HMDS application & soak 40s
* ''No bake''
 
 
**Do this with sample loaded on the PR spinner.
* HMDS application & soak 40s
 
 
*Spin-dry - any spin speed, ~15-30sec
** Do this with sample loaded on the PR spinner.
 
 
*HMDS bake at 100-110°C for 90s.  
* Spin-dry - any spin speed, ~15-30sec
 
 
*Then your normal PR process on top.
* HMDS bake at 100-110°C for 90s.  
 
* Then your normal PR process on top.
 

Latest revision as of 12:41, 10 February 2024

Don't forget that, for lift-off processes, the Imaging (top) Photoresist will lift-off as well if you undercut it too much during develop!

Underlayers for improving PR adhesion

High-temperature (>150°C) underlayers, such as LOL1000/2000, BARC layers tend to improve adhesion of the imaging resist.

  • Substrate prep: O2 plasma (PEii Technics), 10sec
  • Apply high-temp underlayer, eg. LOL1000/2000, PMGI, DSK101 (DUV), DSK42P (DUV)
    • Beware of underlayers that have a develop-rate - undercutting the imaging PR fully can also cause delamination)
  • Apply your Imaging photoresist as normal.

HMDS Process for PR Improving Adhesion

This process tends to improve adhesion between the substrate and subsequent photoresist layers. Use this procedure if you are finding poor adhesion (resist delaminating during develop etc.), or for chemicals (like BHF) that attack the PR adhesion interface strongly.

  • 150°C bake ~2min (Dehydration step)
    • Optionally could instead do Dehydration of: O2 plasma (PEii Technics), 10sec; however this could create more surface SiO2 on silicon.
  • HMDS application & soak 40s
    • Do this with sample loaded on the PR spinner.
  • Spin-dry - any spin speed, ~15-30sec
  • HMDS bake at 100-110°C for 90s.  
  • Then your normal PR process on top.