Applied eyes HT silicon nitride market

Electronic News, March 3, 1997

Santa Clara, Calif.--Targeting a new market, Applied Materials introduced a high-temperature (HT) silicon nitride deposition system, the HT silicon nitride Centura.

The single-wafer, multi-chamber Centura deposits HT silicon nitride films in the pre-metal layers of semiconductors. This enables next-generation applications, such as 64- and 256-megabit DRAMs, flash memories and dual-gate CMOS circuits, with uniform, precisely-controlled thin nitride films at a low thermal budget. Compared with batch furnaces, the HT silicon nitride Centura demonstrates superior film characteristics and lower particles, with competitively high throughput.

"Our customers can especially benefit from the high throughput and interface control that our single-wafer system allows for the thin nitride layers found in capacitor structures of advanced memory devices," said Peter Hey, global product manager at Applied. "In addition to offering exceptional film quality, the system's in-situ chamber clean eliminates periodic wet cleans and provides particle and yield benefits over conventional furnaces. The 20 degrees C per second ramp-up and cool-down rate of the HT chamber allows high wafer throughput, making this single-wafer process very cost competitive, as well."

The HT silicon nitride Centura underwent extensive testing, and units are already on site in the U.S., Japan and Korea. The Centura platform accepts up to three nitride chambers, which can be clustered with other Applied HT chambers for integrated processing applications like oxide-nitride-oxide stacks, poly-nitride and nitride-RTP.

The system enhances DRAM cell capacitor reliability and reduces leakage with its in-situ chamber cleaning and a hydrogen bake process for native oxide removal. The wafers being processed are never exposed to oxygen or moisture and are kept at a constant pressure. This enables a more than 50 percent reduction in defects compared with current batch furnaces and a throughput of more than 40 wafers per hour for a two-chamber system. Within-wafer thickness uniformity on 200mm wafers varies less than 1 percent, 1 sigma at a 50-angstrom thickness.

Applied's new Centura uses the same radiant heating technology as its Poly Centura, Epi Centura and Polycide Centura systems.

"High-temperature processing technologies offer many opportunities for new, innovative process integration solutions, especially as our customers' technical requirements become more challenging," said Stephen Schwartz, GM of Applied's High-Temperature Films division. "We believe that the clustering advantages of these systems will be a major factor in the movement toward single-wafer tools for high temperature processing. The single-wafer architecture of the HT silicon nitride system also allows easy scaling to 300mm wafer processing. In fact, we are already in the advanced stages of developing a 300mm version of this system that will provide the same uniform, low-defect-density films with no throughput loss."