New Approach to Pave the Way for Advanced Interconnects Enabling Future Technology Nodes

Caption: Co ELD on Palladium/Tungsten (Pd/W) for different timed stops to yield an (i) under fill, (ii) potential ideal stop or an (iii) overburden in 28nm holes (Aspect Ratio (AR) 4.5).
Caption: Co ELD on Palladium/Tungsten (Pd/W) for different timed stops to yield an (i) under fill, (ii) potential ideal stop or an (iii) overburden in 28nm holes (Aspect Ratio (AR) 4.5).

During the IEEE IITC conference in Grenoble, the nanoelectronics research center imec and Lam Research Corporation today presented a novel bottom-up prefill technique for vias and contacts. The technique, based on Electroless Deposition (ELD) of Cobalt (Co) is a highly selective method resulting in void-free filling of via and contact holes. Potentially increasing the circuit performance, it is a promising path to scaling advanced interconnects and enabling future logic and DRAM nodes at the 7 nm node and below.

As logic and memory nodes scale, performance of these advanced interconnects is negatively impacted by increasing interconnect resistance. Furthermore, voids that occur in heavily scaled vias severely impact yield. Imec’s industrial affiliation program on advanced interconnects is exploring novel metallization methods to solve these issues. One way to solve the problem is to identify integration and metallization alternatives that provide resistance benefits over conventional technology without compromising reliability and yield. Together with Lam Research, a Co ELD technique was demonstrated as a feasible method for highly selective bottom-up contact fill and via prefill with Cobalt (Co) as an alternative metal to Copper (Cu). Moreover, the high selectivity of the ELD process, at lower cost compared to Chemical Vapor Deposition (CVD), intrinsically ensures a good metal-to-metal interface and paves the way to void-free via filling and increased yield. Trench fill yield and line resistance may also benefit from the de-coupling of line and via aspect ratios, permitting the design of each for optimum Resistance/Capacitance (RC). Therefore, Co prefill ELD has the potential to enable future scaling of advanced logic and memory technologies.

The results were achieved in cooperation with imec’s key partners as part of its core CMOS programs: GlobalFoundries, Intel, Samsung, SK hynix, Sony, TSMC, Amkor, Micron, Utac, Qualcomm, Altera, Fujitsu, Panasonic, and Xilinx.

 

 

About imec
Imec performs world-leading research in nanoelectronics. Imec leverages its scientific knowledge with the innovative power of its global partnerships in ICT, healthcare and energy. Imec delivers industry-relevant technology solutions. In a unique high-tech environment, its international top talent is committed to providing the building blocks for a better life in a sustainable society. Imec is headquartered in Leuven, Belgium, and has offices in Belgium, the Netherlands, Taiwan, USA, China, India and Japan. Its staff of about 2,200 people includes almost 700 industrial residents and guest researchers. In 2014, imec’s revenue (P&L) totaled 363 million euro. Further information on imec can be found at www.imec.be. Stay up to date about what’s happening at imec with the monthly imec magazine, available for tablets and smartphones (as an app for iOS and Android), or via the website www.imec.be/imecmagazine
Imec is a registered trademark for the activities of IMEC International (a legal entity set up under Belgian law as a “stichting van openbaar nut”), imec Belgium (IMEC vzw supported by the Flemish Government), imec the Netherlands (Stichting IMEC Nederland, part of Holst Centre which is supported by the Dutch Government), imec Taiwan (IMEC Taiwan Co.) and imec China (IMEC Microelectronics (Shanghai) Co. Ltd.) and imec India (Imec India Private Limited).
About Lam Research
Lam Research Corp. (NASDAQ: LRCX) is a trusted global supplier of innovative wafer fabrication equipment and services to the semiconductor industry. Lam’s broad portfolio of market-leading deposition, etch, strip, and wafer cleaning solutions helps customers achieve success on the wafer by enabling device features that are 1,000 times smaller than a grain of sand, resulting in smaller, faster, and more power-efficient chips. Through collaboration, continuous innovation, and delivering on commitments, Lam is transforming atomic-scale engineering and enabling its customers to shape the future of technology. Based in Fremont, Calif., Lam Research is a NASDAQ-100 Index® and S&P 500® company whose common stock trades on the NASDAQ® Global Select Market™ under the symbol LRCX. For more information, please visit http://www.lamresearch.com.