Enhancement of proton beam writing in PMMA through optimization of the development procedure

✍ Scribed by S. Bolhuis; J.A. van Kan; F. Watt

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 346 KB
• Volume: 267
• Category: Article
• ISSN: 0168-583X
• DOI: 10.1016/j.nimb.2009.03.045

✦ Synopsis

The development step of the proton beam writing (PBW) process plays an important role in the performance characteristics that can be achieved with a resist-developer system. A common developer for PBW in PMMA resist is the mixture IPA/water, used in combination with conventional dip development.

In this paper, we investigate the use of the GG-developer, much used in the LIGA-process, and show that the GG-developer is able to dip develop proton beam written structures of feature sizes down to 133 nm in a PMMA layer of 2.4 lm thickness. Moreover, both contrast and sensitivity are found to be higher for the GG-developer compared to dip development in 7:3 IPA/water.

The development method as well as the type of developer influences resist development. The effect of megasonic agitation (frequency of 1 MHz) on the development of structures in PMMA was investigated for the developer 7:3 IPA/water. Compared to conventional dip development, structures developed with megasonic agitation showed larger feature sizes, indicating that the development rate was increased. However, performance characteristics were not enhanced: both contrast and sensitivity were found to be lower than after dip development in 7:3 IPA/water.