Gravity Edge Hold

Historically robot designers have gone to great lengths and expense to develop control systems that maximize robot speed while minimizing the possibility of wafer sliding on the end effector. Today, the capability of most existing robotic drive mechanisms exceeds the market’s need for resolution and speed. However, fabs are still limited by the coefficient of friction between the wafer and the end effector. Many robots today have end effectors that allow wafer sliding even at very low speeds.

Fabworx Solutions’ latest end effector technology, Gravity Edge Hold™ (GEH) allows transfers at high-speed, eliminates wafer sliding, and even repositions out-of-alignment wafers, enabling throughput increases in many tools. 

As a wafer is lowered onto a GEH end effector, four cams engage to re-center and hold the wafer. With GEH, placement repeatability is improved to <(+/-) 0.01mm (0.0004 in.).

Gravity Edge Hold technology gently holds a wafer in a pocket with minimal wafer contact to:

• Reduce particles caused by wafer sliding in the end effector pocket.
• Position a wafer precisely and repeatedly on the end effector reducing out-of-position alarms and potentially improving process uniformity.
• Capture and re-center an out-of-position wafer (up to the limits of the pocket size), reducing tool assists and downtime.
• Allow transfers at top robot speed without wafer sliding.

GEH technology is compatible with 150mm, 200mm and 300mm wafers, is applicable to both vacuum and atmospheric robots, and is designed to retrofit onto most existing robots in most existing tools.

In November 2010, an article on GEH technology was published in Issue 35 of Future Fab International exploring the repeatability and throughput improvements possible with GEH technology. Click here to download the full article.

Gravity Edge Hold technology is available in numerous shapes and sizes to accommodate specific applications. Contact us today to discuss how Gravity Edge Hold technology can benefit your fab.

Patents pending in US, Taiwan, Korea, China, and Singapore