Product Briefing Outline: Novellus Systems has launched the ‘VECTOR CFD’ family of films for the company’s VECTOR Express, VECTOR Extreme and VECTOR Excel plasma-enhanced chemical vapor deposition (PECVD) systems. The Conformal Film Deposition (CFD) suite of dielectric films consists of oxide, doped oxide and nitride films are deposited at temperatures ranging from 50 degrees to 450 degrees Celsius. These films provide solutions for emerging sub-2X nm logic and memory applications, including front-end-of-line (FEOL) liners and spacers used in tri-gate transistors and FinFETs, bitline spacers, and through silicon via (TSV) dielectric liners, amongst other applications.
Problem: In an era of shrinking dimensions and with the advent of 3D transistors, the industry demand for CFD films is expected to significantly expand. Depositing CFD films on the VECTOR platform is claimed to provide the required within-wafer and wafer-to-wafer repeatability with significantly higher throughput and lower chemical costs needed for leading-edge volume production requirements.
Solution: (Figure 1a,b) shows CFD oxide and nitride films with 100 percent step coverage that have been deposited at temperatures less than 450 degrees Celsius. Temperatures in this range are compatible with FEOL implant processes and ensure consistent shallow junction depths and doping profiles. These CFD films show no pattern dependency across a die, resulting in consistent sidewall profiles in the transistor, memory and peripheral areas of devices. VECTOR CFD films can also be deposited at temperatures below 80 degrees Celsius, making them the perfect candidate for deposition directly onto photoresists. This integration sequence can be used to enable a simplified, spacer-based double patterning scheme, where photoresist is used as the patterning core. Adoption of this approach is claimed to yield significant cost benefits for the customer by eliminating one etch and one lithography step as compared to conventional double patterning schemes. (Figure 2,a,b,c) shows a conformal oxide film being used as a TSV liner where 100 percent step coverage can be maintained on vias with aspect ratios in excess of 20:1. This step coverage improvement gained, allows engineers to reduce the overall field thickness of the dielectric, which in turn translates into reduced oxide CMP costs.
Applications: Sub-2X nm logic and memory applications, including front-end-of-line (FEOL) liners and spacers used in tri-gate transistors and FinFETs, bitline spacers, etch stop layers, resistor protect layers, double patterning spacers using amorphous carbon or photoresist cores, and through silicon via (TSV) dielectric liners.
Platform: Novellus’ CFD films are deposited using an innovative version of VECTOR’s patented multi-station sequential processing (MSSP) architecture. The system has been optimized to meet the demanding technical requirements for conformality while also minimizing chemical consumption. In comparison to single wafer deposition systems, MSSP results in superior film uniformity and repeatability with significantly higher productivity.
Availability: July 2011 onwards.