In-line process monitoring of spray developed diazoquinone photoresist
Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in December 2013. Physical copy available through RIT's The Wallace Library at: TK7874 .S28 1985
As the minimum feature size of IC devices is reduced, the control of linewidth becomes moire and more critical. An in-iine process monitor for spray developed diazoqumone- type photoresist has been constructed which enables a spin-developing module to automatically compensate for the numerous variables which can affect linewidths. The development time of a wafer is varied depending on the dissolution rate of the photoresist. Development is monitored by reflecting light from the wafer surface which is sensed by a photodiode. Variable development time has been shown to control linewidths as exposure dose and photoresist coating thickness were changed. The relationship oetween the time of developer breakthrough at the wafer surface and the total development time to achieve equal lines and spaces on a resolution test target was found to be linear for short development times typical of in-line wafer processing. Additionally, this monitoring technique has been shown to yield powerful process diagnostic inrormation capable of improving one 's current resist process.