Aviza reported that a ‘leading' Taiwanese foundry has placed an order for its Celsior (pictured) next-generation single wafer atomic layer deposition (ALD) system. The system will be used for high volume 300mm DRAM manufacturing at the 90nm node. Vesta also announced that a major semiconductor manufacturer in Japan has qualified and issued system acceptance for its ALD tool for multiple high-k applications in 300mm manufacturing.

Aviza's Celsior is based on a central transfer hub acquired from Trikon Technologies, who merged with Aviza Technology in December 2005. A patented showerhead is designed to achieve uniformity levels of less than 1% thickness variation across a 300mm wafer.

Vesta mysteriously lists South Korean company IPS at the end of their press release without mention in the main text. Some digging on the web reveals that IPS is an ‘affiliated company' supplying equipment to Vesta. In August 2004, the companies entered into an exclusive technology agreement for the marketing, sales, service and future development efforts focusing on the global atomic layer deposition (ALD) market. Vesta provides global support for IPS's product lines of ALD, metal ALD/VPD, Multipole Inductively Coupled Plasma (MICP) etch and LCD etch. The agreement also covered joint development efforts focusing on ALD technology and the delivery of R&D and production-proven processes for the deposition of thin films.

Previously (http://www.fabtech.org/content/view/1653/2/), we reported that a ‘leading' Asian memory manufacturer had ordered equipment combining Aixtron's Genus 300mm atomic layer deposition (ALD) StrataGem and atomic vapor deposition (AVD) technologies. Aixtron merged/acquired Genus a year ago.

Veeco is another company hungry for ALD sales - last week it announced that it had appointed James T. Jenson as Vice President, General Manager of Veeco's physical vapor deposition (PVD) and atomic layer deposition (ALD) product lines. Jenson will be responsible for overseeing these technologies as they make the transition from development to production. Veeco sees this as taking place in the hard-disk drive industry where the technology is used in making next-generation thin film magnetic heads (TFMHs).

Last month, Oxford Instruments also announced a new atomic layer deposition (ALD) tool, FlexAL, following successful beta system results at the Eindhoven University of Technology (TU/e). FlexAL offers low temperature deposition, high density films and high film purity while also giving thermal ALD processing capability in the same system. Processes have already been developed for a range of materials including TiN, HfO2 high-k dielectric, Al2O3 deposition down to room temperature and single-metal Ru. The systems have the ability to handle from small sample pieces up to full 200mm wafers. The company is presently running sample trials in its Applications Laboratory for a number of potential customers.

Although ALD has been touted for high-k dielectric gate insulator and metal gate deposition, its main applications so far have been in DRAM capacitor and thin-film head (TFH) production. A unique property of ALD is conformal deposition of material into high aspect ratio features. Some development work has been carried out on the gate application, but the main problem with the technology is a severe productivity-precision trade-off - the tools offer highly accurate deposition but with a time-cost resulting from the atomic-level process. As can be seen from these announcements, this is still a problem.

The high-k application for the Vesta tool is likely to be for capacitor formation and the others are either development-level or fit in to the DRAM/TFH mold. Although DRAM production is an important sector, until ALD penetrates into the transistor, it will remain a niche technology. This penetration is contingent on the failure of mainstream deposition technologies, such as CVD, to provide working devices in sufficient numbers.

By Dr Mike Cooke