Modifying and Installing an Ultratech Stepper : a success story

The scope of the project described here was to remove an Ultratech Titan GH Line stepper taking it from operating in the cleanroom in Europe, transporting it to our client in the USA, modifying the stepper to run 5 inch reticles and 6 and 8 inch wafers ,installing it , and then subsequently demonstrating it operational to OEM specifications.

Success in this project was achieved by careful planning at each stage, and close work together with our suppliers and our client.

Ultratech Stepper Assessment and Removal

At,our aim is to minimise the risk to the client and maximise the profit return by providing reliable used equipment. To this end, the initial work of the project was:-

  • Thoroughly test the Ultratech stepper prior to removal
  • Performance was measured by running auto-uniformity at various field sizes to check illumination.When auto-uniformity was run with the large aperture, it was discovered that the light pipe was 55 x 18.
  • The reticle and wafer loading system was excercised and no problems were found.
  • Short step focus was checked and verified.
  • Software was backed up to floppies.

It was planned to repeat all tests done on removal again on install, then convert to 5 inch reticle and 8 inch/ 6 inch setup with universal chuck. System was prepared for removal by de-cabling and marking cables, removing sensitive subsystems etc. Main body of system removed from clean room to packing area. Main body packed in crate. Chamber dismantled and removed from clean room to packing area. Racks and all other parts removed from clean room to packing area. Crates shipped via air to USA.

Ultratech Stepper Installation in the USA

the following steps were perfomed during install:-

  • Cassette boat platforms modified to allow 8 inch wafer use.
  • The robot was set up for 6 and 8 inch wafer use.
  • Reticle Position Test was performed.
  • Short Step Focus was verified to be 1 um, D.O.F.=3um. Ran RM5 and updated variables. Ran SXS Overlay, 2 wafers. Results good. Cycled several wafers, all ok. Cycled reticle several times ok.
  • All tests that were carried out at decommission had been repeated during the install and were succesfull.
  • The original 5 inch chuck was replaced with a universal chuck and the vacuum lines were appropriately modified.
  • The system was then converted from 6 inch reticle setup to 5 inch reticle setup.
  • Ultratech stepper move into climate controlled chamber
    After conversion, the reticle loading was calibrated and thoroughly tested.
    In order to allow the client to achive a field width of over 26 mm, the 55 x 18 lightpipe was removed and replaced with a 44 x 22 lightpipe.The illuminator was moved to increase the field size.
  • The modified 8 inch cassette platforms were added.
  • The MVS was setup and operation was verified
  • The machine was handed over to production for testing.