Semiconductor Photoresist, And Cleaning Process Tools

Lift Off Resist (LOR) Processing

This application note refers to micro-chem LOR resist though different resists can be used.  The S-Cubed LOR processor is designed to perform both LOR and Photoresist Patterning processes automatically and sequentially. Further the LOR spin on coater can then also be utilized as the develop module for the develop process for the system. Both S-Cubed Flexi and Scene 8/12 series systems can perform this function.

Lift Off Resist Operation

S-Cubed employ’s two methods of lift off processing depending on the needs and practices of the customer.  The first technique is to “soak” the wafers to be “lifted off” in hot (approximately 70C) NMP. The treated wafers are then placed on a “pin” type chuck and “blasted” with high pressure NMP followed by an IPA rinse followed by DIW spin rinse and dry.  All of the spin process are carried out on the chuck wiLift Off Resist Processing Exampleth the various fluids discharged into annular drains at differing heights so that fluids can be recycled or discharged as appropriate.

The second method is somewhat simpler and can be done effectively at lower cost in a simpler system.  We simply blast the wafer surface with high pressure acetone and use a recycling system to recover the spent acetone with the final acetone rinse being the means by which the recycling material is refreshed.  The system is Nitrogen inerted for safety and the process is both fast and effective.  The images below are the micro graphs of metal films after such lift off processing.

LOR Process Outline

For the LOR and PMGI coat process the following is the process flow, the wafers are coated with both materials sequentially without exiting the tool.

  • Wafer Is Loaded To The Lor Spin Module And Coated
  • Baked In A Hot Plate Chamber
  • Cooled On A Chill Plate
  • Coated In The Second Spin Module In The System With Photo Resist.
  • Baked In A Hot Plate Chamber
  • Cooled On A Chill Plate.

For the Develop process.

  • Wafer is loaded to the LOR spin Module (this module is compatible with aqueous processes, the develop process uses TMAH which is aqueous, this will have the effect of not only performing the develop on both the photoresist and LOR films but will also act to maintain the spin bowl in clean condition.
  • Baked if so desired, then chilled.

In this way the entire operation of the process is carried out without operator involvement, eliminating the possibility of an operation not being properly sequenced and carried out. Further the entire tool does double duty thereby saving time, money and footprint…lowering the cost of ownership.

For more information on S3 LOR process automation,
please contact our engineering team today.