The international technology roadmap of semiconductors (ITRS) is approaching the historical end point and we observe that the semiconductor industry is driving complementary metal oxide semiconductor (CMOS) further towards unknown zones. Today's transistors with 3D structure and integrated advanced strain engineering differ radically from the original planar 2D ones due to the scaling down of the gate and source/drain regions according to Moore's law. This article presents a review of new architectures, simulation methods, and process technology for nano-scale transistors on the approach to the end of ITRS technology. The discussions cover innovative methods, challenges and difficulties in device processing, as well as new metrology techniques that may appear in the near future.

State of the Art and Future Perspectives in Advanced CMOS Technology.

This paper will examine the future for critical dimension (CD) metrology. First, we will present the extensive list of applications for which CD metrology solutions are needed, showing commonalities and differences among the various applications. We will then report on the expected technical limits of the metrology solutions currently being investigated by SEMATECH and others in the industry to address the metrology challenges of future nodes, including conventional CD scanning electron microscopy (CD-SEM) and optical critical dimension (OCD) metrology and new potential solutions such as He-ion microscopy (HeIM, sometimes elsewhere referred to as HIM), CD atomic force microscopy (CD-AFM), CD small-angle x-ray scattering (CD-SAXS), high-voltage scanning electron microscopy (HV-SEM), and other types. A technical gap analysis matrix will then be demonstrated, showing the current state of understanding of the future of the CD metrology space.

Gaps analysis for CD metrology beyond the 22nm node

Shrinking design rules and reduced process tolerances require tight control of CD linewidth, feature shape, and profile of
the printed geometry. The Holistic Metrology approach consists of utilizing all available information from different
sources like data from other toolsets, multiple optical channels, multiple targets, etc. to optimize metrology recipe and
improve measurement performance. Various in-line critical dimension (CD) metrology toolsets like Scatterometry OCD
(Optical CD), CD-SEM (CD Scanning Electron Microscope) and CD-AFM (CD Atomic Force Microscope) are typically
utilized individually in fabs. Each of these toolsets has its own set of limitations that are intrinsic to specific
measurement technique and algorithm. Here we define "Hybrid Metrology" to be the use of any two or more metrology
toolsets in combination to measure the same dataset. We demonstrate the benefits of the Hybrid Metrology on two test
structures: 22nm node Gate Develop Inspect (DI) & 32nm node FinFET Gate Final Inspect (FI). We will cover
measurement results obtained using typical BKM as well as those obtained by utilizing the Hybrid Metrology approach.
Measurement performance will be compared using standard metrology metrics for example accuracy and precision.

A holistic metrology approach: hybrid metrology utilizing scatterometry, CD-AFM, and CD-SEM

When the international technology roadmap of semiconductors (ITRS) started almost five decades ago, the metal oxide effect transistor (MOSFET) as units in integrated circuits (IC) continuously miniaturized. The transistor structure has radically changed from its original planar 2D architecture to today’s 3D Fin field-effect transistors (FinFETs) along with new designs for gate and source/drain regions and applying strain engineering. This article presents how the MOSFET structure and process have been changed (or modified) to follow the More Moore strategy. A focus has been on methodologies, challenges, and difficulties when ITRS approaches the end. The discussions extend to new channel materials beyond the Moore era.

Miniaturization of CMOS.

This paper will provide a high level overview of the future for in-line high volume manufacturing (HVM) metrology for the semiconductor industry. First, we will take a broad view of the needs of patterned defect, critical dimensional (CD/3D) and films metrology, and present the extensive list of applications for which metrology solutions are needed. Commonalities and differences among the various applications will be shown. We will then report on the gating technical limits of the most important of these metrology solutions to address the metrology challenges of future nodes, highlighting key metrology technology gaps requiring industry attention and investment.

HVM metrology challenges towards the 5nm node

Shrinking design rules and reduced process tolerances require tight control of critical dimension (CD) linewidth, feature shape, and profile of the printed geometry. The holistic metrology approach consists of utilizing all available information from different sources such as data from other toolsets, multiple optical channels, multiple targets, etc., to optimize metrology recipe and improve measurement performance. Various in-line CD metrology toolsets such as scatterometry optical CD, CD-SEM, and CD-AFM are typically utilized individually in fabs. Each of these toolsets has its own set of limitations that are intrinsic to specific measurement technique and algorithm. Here we define "hybrid metrology" to be the use of any two or more metrology toolsets in combination to measure the same dataset. We demonstrate the benefits of the hybrid metrology on two test structures: 22-nm-node gate develop inspect and 32-nm-node fin-shaped field effect transistor gate final inspect. We will cover measurement results obtained using typical BKM (nonhybrid, single toolset standard results) as well as those obtained by utilizing the hybrid metrology approach. Measurement performance will be compared using standard metrology metrics; for example, accuracy and precision.

Holistic metrology approach: hybrid metrology utilizing scatterometry, critical dimension-atomic force microscope and critical dimension-scanning electron microscope

Improvement in metrology performance when using a combination of multiple optical channels vs. standard single
optical channel is studied. Two standard applications (gate etch 4x and STI etch 2x) are investigated theoretically
and experimentally. The results show that while individual channels might have increased performance for few
individual parameters each - it is the combination of channels that provides the best overall performance for all
parameters.

Ronen Urensky

Papers

A holistic metrology approach: hybrid metrology utilizing scatterometry, CD-AFM, and CD-SEM

Holistic metrology approach: hybrid metrology utilizing scatterometry, critical dimension-atomic force microscope and critical dimension-scanning electron microscope

A holistic metrology approach: multi-channel scatterometry for complex applications