C. S. Park, G. Bersuker, S. C. Song, P. Kirsch & B. H. Lee, SEMATECH, Austin, Texas; R. Jammy, IBM assignee to SEMATECH

ABSTRACT

This paper describes recent progress in high-k/metal gate stacks required for MOSFET scaling to the 32nm technology node. Band-edge metals for n- and p-MOSFETs have been developed through effective work function (WF) tuning, achieved by optimized doping of the high-k gate stacks. The mechanism of the EWF tuning is the dipole formation at the interface of the high-k dielectric and SiO₂ interfacial layer. Possible solutions to the flatband voltage (V_fb) roll-off issue were obtained, an issue that presents the most significant challenge to achieving low pMOSFET threshold voltage (|V_t|) at low EOTs. The gate-first high-k/metal gated n- and pMOSFETs with low |V_t| and low EOT suitable for 32nm technology node applications have been successfully demonstrated.

Paul Kirsch, S.C.Song, & Prashant Majhi, SEMATECH, & Raj Jammy, IBM assignee to SEMATECH

ABSTRACT

Historically, both logic and memory have been front-end process technology drivers.  For example, logic development resulted in shallow trench isolation eliminating “bird’s beak” isolation oxide. Ion implantation increased doping densities needed for high mobility n-channel transistors.  More recently, embedded SiGe, dual stress nitride, Hf-based high-k and metal gates have been logic performance drivers. On the other hand, memory development has spawned plasma doping, nitrided oxides, Al-based high-k and borderless contacts, as well as pushed lithography critical dimension. Motivation for memory development work is multi-fold. First, memory revenues grow faster than logic revenues. Second, the growth potential of memory materials and processes in embedded applications holds tremendous promise to improve system level performance. Finally, many new materials are emerging to address memory-scaling challenges but screening these many options is difficult.  Building on extensive knowledge of gate dielectric and metal gate materials gained through several years of experience, SEMATECH is pursuing the challenge of materials development for DRAMs, Flash, PRAM, and ReRAM as described below. SEMATECH has successfully provided solutions to the semiconductor industry and this deep knowledge accelerates memory progress. 

By Don Baskin and Paul Scheibmeir, ATDF, Texas, USA

ABSTRACT

Atomic layer deposition (ALD) has become a leading technology candidate for enabling the semiconductor industry to fabricate devices below 90nm and forge into the realm of nanotechnology.  One of the most effective precursors for ALD is trimethylaluminum (TMAl), a pyrophoric liquid that ignites upon contact with air and reacts violently with water or atmospheric moisture.  Because of its reactivity, TMAl requires strict safety protocols for handling, containment, and use.  Becoming familiar with andadopting these procedures may require a steep learning curve and rapid assimilation of new safety regiments.  Such was the experience of ATDF, the global R&D foundry based in Austin, TX.

By Mark R. Litchy, Donald C. Grant, CT Associates, Inc., USA and Reto Schoeb, Levitronix GmbH, Switzerland

ABSTRACT

Delivery systems used to supply slurry to CMP planarization tools can damage slurry.  In this experiment, four slurries were circulated in a simulated slurry delivery loop at a fixed flow rate and pressure using a variety of pumps (bellows, diaphragm, and magnetically levitated centrifugal) to determine the effect of circulation on the slurry health.  During each test, a number of slurry health parameters were monitored including the size distribution of the particles in the slurry. Most slurry health parameters were unaffected during the tests.  However, significant changes in the large particle tail (particles ≥ 0.5μm) of the slurry particle size distributions (PSD) were observed.  Both the pump and slurry type played important roles in the magnitude of the change.  In some slurries, large increases in the large particle concentrations were observed during circulation with diaphragm and bellows pumps, while in other slurries increases were not observed.  With the magnetically levitated centrifugal pumps, minimal changes were observed, regardless of the type of slurry tested.

Robert L. Rhoades, Entrepix, Inc., Arizona, USA, & Gautam Banerjee, Air Products and Chemicals, Inc., Arizona, USA

ABSTRACT

Advanced semiconductor devices have evolved over recent years through a series of steps that included the introduction of both copper metal and low-k dielectric materials for the interconnect module. As designs continue to push toward faster speeds and smaller linewidths (65, 45, 32 and 22nm), the dielectric constant (k) required at each successive technology node is projected to continue dropping toward effective k-values of 2.5 or below. The new materials required to reach these values are generally referred to as ultra low-k, or ULK, dielectrics. Developing such ULK materials is an incredible challenge, but several candidate materials are now available. However, integrating them successfully into a reliable CMOS device manufacturing flow is proving to be extremely difficult, especially with regard to the CMP process module.  

C.P. Jones, A.M. Pierce, B.R. Roberts, BOC Edwards, USA

ABSTRACT

Electrochemically regenerated ion exchange (ERIX™) concentrates chemical waste and recovers water for reuse.  ERIX incorporates proven electro-deionization (EDI) technology, ion exchange and electro-dialysis in a single cell.  EDI and ion exchange are used commercially to produce ultra-pure water.  In EDI cells, the mixed-bed ion exchange deionizes the solution as it passes through.  The electrodialytic components move the ions from the resin to a concentrate stream, thereby achieving a continuous ion exchange process without the need for periodic regeneration of the cell or addition of regenerant chamicals.  ERIX can be used for the removal of both cations and anions. 

Robert Preisser, Atotech Deutschland, Berlin, Germany

ABSTRACT

The introduction of copper metallization into semiconductor manufacturing has been a significant step in process technology and device scaling. However, the wet electro-deposition technology used suffers from a number of drawbacks. Impurities deposited on the copper anode from organic additives in the electrolyte solution can subsequently be released and deposited on the wafer, leading to killer-defect particles. Also, gas bubbles from the electrolytic decomposition of water can be trapped in the deposited metal, leading to further process issues. 

Josep Arnó, R&D Director, ATMI Inc., & Craig Printy, National Semiconductor, USA

ABSTRACT

Under certain circumstances, the manufacture of electronic devices requires the use of dilute gases. These materials are typically supplied in premixed high-pressure cylinders containing the active gas in a dilute form. The pressures and delivery flow rates of these precursors are accurately controlled through sophisticated delivery systems that include mass flow controllers, pressure regulators, and transducers. However, typical delivery systems do not integrate equipment that measures the accuracy and real-time stability of the gas blend composition. Such chemical analyzers may be especially important to monitor the concentration of mixtures during doping applications where precise dosing is critical. 

J. Connelly & W. Curcie, Infineon Technologies, Richmond, Virginia, USA

ABSTRACT

In high-volume semiconductor factories (Fabs), the use of tote supply for chemicals and slurries can significantly reduce operating costs. In cases where systems were not originally designed to accommodate totes, transitioning to a tote supply may require custom engineering and logistics solutions. This article relates the experiences of one factory in transitioning several systems from drum to tote supply. These efforts saved over $340,000 annually. 

Bill Reith, Senior Supplier Quality Engineer, Freescale Semiconductor, Scotland

ABSTRACT

Developing and releasing a material specification is only a starting point from which subsequent and ongoing improvements ensue. In order to optimize the performance of any material it is important to verify, using support data, the critical requirements for the product in the device or process application. Armed with knowledge of the critical parameters, you can compare objectively the performance of different materials from different suppliers.