An Innovative Material for In

DuPont Engineering Polymers, Newark, Delaware

Vespel parts are made from a unique polymer by DuPont that has been called a problem solver for the semiconductor industry. Vespel SPC is a new generation of Vespel polyimide parts and shapes for semiconductor manufacturing, with improved performance and added value in etching chambers and other demanding wafer processing environments.

According to Dr. Gary Poovey of Lam Research Corp., a designer and manufacturer of processing equipment used in the fabrication of integrated circuits, Vespel has several characteristics which are crucial for in-chamber applications. Vespel aElectronics Tech Briefs, June 1999 survives high temperatures, resists heat cycling, and holds its shape under pressure. It is also very stable in plasma environments, and demonstrates excellent mechanical strength. Finally, because Vespel does not transfer heat, it does not attract depositions as readily as other materials, leading to greater cleanliness in the chamber.

Dr. Ray DeColibus, developer of the Vespel SCP formulation, confirms that Vespel's metal ion contamination levels tend to be very low compared with other polymers. Vespel is very stable oxidatively, even at very high temperatures, and offers enhanced plasma resistance, which is particularly critical to semiconductor manufacturers.

The largest current consumer of Vespel in the semiconductor industry is the etch segment, where it is used for wafer clamping rings, gas distribution plates, insulator rings, chamber liners, edge rings, confinement rings, screws and clips, and lift-pin components. These Vespel parts contribute to improved die yield through increased etch uniformity and reduced edge effect. Vespel is also used in PVD, CVD, ion implant, and other processes.

Because of its unique combination of properties, Vespel is being used to replace quartz in a variety of semiconductor applications. Many semiconductor manufacturers are successfully substituting Vespel for quartz without making any changes in their processing conditions, while simultaneously seeing benefits to their overall wafer-fabrication processes. For example, in wafer clamping rings, Vespel's greater toughness prevents fracturing that can occur with the use of quartz. Cover rings and focus rings have also been converted to Vespel, to take advantage of its superior etch uniformity and cleanliness.

In recently documented applications, parts made of Vespel have lasted up to three times longer than standard polyimides. Through its durability, reliability, long life, reduced maintenance, and increased yields, it helps semiconductor manufacturers reduce their cost of ownership in current etch systems and in next-generation high-density plasma systems. At the time of initial purchase, and over the lifetime of the part, the cost of Vespel parts is highly competitive with quartz and ceramic.

To meet the need for larger parts that can stand up to aggressive chamber conditions and protect process purity, DuPont offers Vespel in diameters ranging from one-quarter inch up to 22 inches. The king-sized parts are ideal for larger confinement rings, shield rings, focus rings, and various other uses.

For more information, visit the DuPont Semiconductor Enterprise web site: www.dupont.com/semiconductors, or the Vespel web site: www.dupont.com/enggpolymers/americas/products/vespel.html or call 1-800-972-7252.

This article first appeared in the June, 1999 issue of Electronics Tech Briefs Magazine.

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