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Product Briefing Outline: Applied Materials has launched the ‘Centura' ‘Mariana' Trench Etch system. The Mariana is claimed to be the first system that can etch 80:1 aspect ratio trenches - a critical capability that will allow DRAM capacitor scaling beyond 70nm. Dual-frequency tuning capabilities tightly control the etch profile and CD (critical dimension) with 2 percent etch depth non-uniformity are claimed. The system's specialized plasma chemistry is claimed to significantly improve mask selectivity. Mariana systems have already been purchased by customers for 70nm DRAM production, Applied said.

Problem: DRAM technology faces multiple challenges with memory cell scaling. A key aspect is the need to increase the array transistor channel length by extending it into the silicon surface. The loss of storage capacitance is caused by rapid decrease of the feature size. Very large aspect ratios allow for sufficient capacitances in spite of smaller process structures.

Solution: The system is designed to etch trenches less than 100nm wide at aspect ratios greater than 80:1 for capacitor structures in 70nm devices and beyond. Independent gas injection enhances CD control, while the chamber's tunable gas distribution and multiple frequency configuration supports a claimed 2 percent etch depth non-uniformity to the wafer's edge. A tunable, dual-zone, high-temperature electrostatic chuck and specialized chemistry improve mask selectivity and CD control, even during high etch rate processes.  The system's high conductance chamber, controlled chamber environment, and advanced process control implemented via in situ metrology and process state monitoring improve process stability and repeatability across the wafer, from wafer to wafer and from system to system, according to Applied Materials.

Applications: DRAM capacitor trench etching at the 70nm node and below.

Platform: Closed-loop temperature control maximizes mean wafers between cleans. Simplified design streamlines maintenance and facilitates the industry's shortest mean time to clean and recover. The dual-zone, ceramic electrostatic chuck and advanced chamber materials aid stringent defect control and lower consumables costs. Applied's Metron division also offers a pre-qualified abatement solution for the Mariana with its Marathon 8500 system.

Availability: April 2007 onwards.