A major semiconductor discrete manufacturer has purchased an additional Surface Tension Gradient Dryer (STGD) from MicroTech because of its ability to dry thin wafers without damage to the wafer's thin films. This is the second order to the manufacturer by MicroTech, a Silicon Valley wet process station supplier.
The 200mm high-aspect ratio wafers utilize tape during processing because the wafers are so thin. The user has reported the following process performance of the STGD:
Zero tape adhesive attack/undercut
Zero tape adhesive residuals at edges of wafers
Minimal contact or vibrations on thin wafers up to 50 micron thickness
Minimal handling contact at load by the Teflon pushup bar fixture, a proprietary mechanism to "float" the wafers during processing.
MicroTech's Surface Tension Gradient Dryer utilizes Marangoni technology. The system uses very small amounts of IPA, approximately 5 ml, which is vaporized above the DI water during the process. The dryer has no moving parts, leaves no watermarks and completely eliminates the DI water from deep trenches and vias. At the end of the cycle, warm N2 dries the wafer cassette.