The Benefits of High Landing Energy for E-Beam Inspection

Patterson, Oliver D.; Hafer, Richard F.; Tang, Xiaohu; Lei, Shuen-Cheng Chris

doi:10.1109/tsm.2016.2593632

Cited by 4 publications

(2 citation statements)

References 9 publications

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“…The non-destructive characterization of buried nanoscale structures is an important challenge in different application areas. For the semiconductor industry application examples are buried defect detection 1 , lithography mask inspection 2 , and metrology 3 . In the application of biomedical diagnostics example applications are the imaging of the internal structures of cells and tissues 4 .…”

Section: Introductionmentioning

confidence: 99%

Optimization of acoustic coupling for bottom actuated scattering based subsurface scanning probe microscopy

Neer

Quesson

et al. 2019

Review of Scientific Instruments

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The characterization of buried nanoscale structures non-destructively is an important challenge in a number of applications, such as defect detection and metrology in the semiconductor industry. A promising technique is Subsurface Scanning Probe Microscopy (SSPM), which combines ultrasound with Atomic Force Microscopy (AFM). Initially, SSPM was used measure the viscoelastic contrast between a subsurface feature and its surrounding medium. However, by increasing the ultrasonic frequency to >1 GHz, it has been shown that SSPM can also measure acoustic impedance based contrasts. At these frequencies it becomes difficult to reliably couple the sound into the sample such that the AFM is able to pick up the scattered sound field. The cause is the existence of strong acoustic resonances in the sample, the transducer and the coupling layer-the liquid layer used to couple the sound energy from the transducer into the sample-in combination with the nonlinearity of the tipsample interaction. Thus, it is essential to control and measure the thickness of the coupling layer with nanometer accuracy. Here, we present the design of a mechanical clamp to ensure a stable acoustic coupling. Moreover, an acoustic method is presented to measure the coupling layer thickness in realtime. Stable coupling layers with thicknesses of 700 ± 2 nm were achieved over periods of 2-4 hours. Measurements of the downmixed AFM signals showed stable signal intensities for >1 hour. The clamp and monitoring method introduced here makes scattering based SSPM practical, robust and reliable and enables measurement periods of hours.

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Section: Introductionmentioning

confidence: 99%

Optimization of acoustic coupling for bottom actuated scattering based subsurface scanning probe microscopy

Neer

Quesson

et al. 2019

Review of Scientific Instruments

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“…4 In addition, high resolution SEM is prone to damage materials due to the high energies involved. 5 This is increasingly a problem as maintaining the material integrity becomes critical at smaller length scales.…”

Section: Introductionmentioning

confidence: 99%

Quantitative tomography with subsurface scanning ultrasound resonance force microscopy

Fillinger

Sadeghian

2019

Metrology, Inspection, and Process Control for Microlithography XXXIII

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Extracting quantitative information about dimensions and material properties of buried structures is continuing to be an important but difficult task in metrology. Examples of questions asking for this capability include critical dimension metrology of fins such as the profile (bottom width, top width, height) or the presence and extent of voids. In recent years TNO has demonstrated the concept of using Atomic Force Microscopy (AFM) in combination with ultrasound to image buried structures based on their (visco-)elasticity in a technique called Subsurface Scanning Ultrasound Resonance Force Microscopy (SSURFM). We have successfully imaged structures less than 10 nm wide, as well as structures buried up to a micrometer deep. However, extracting quantitative information from this data is not trivial, as the induced stress field in the sample depends on many parameters in a non-linear way: experimental parameters such as applied force, tip size and tip shape, and geometry and material properties of the buried structures themselves. Therefore, measurements based on this technique have a point spread function which varies in a complicated way with the sample properties that need to be measured. However, a solid understanding of the physics and mechanics involved, and the modeling of the expected structures and their response to externally applied stress, enable quantitative measurements. We specifically show our progress on characterizing a sample comprising fins from a 7 nm node manufacturing test run.

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Mapping buried nanostructures using subsurface ultrasonic resonance force microscopy

Mohtashami

Thijssen

et al. 2018

Ultramicroscopy

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The Benefits of High Landing Energy for E-Beam Inspection

Cited by 4 publications

References 9 publications

Optimization of acoustic coupling for bottom actuated scattering based subsurface scanning probe microscopy

Optimization of acoustic coupling for bottom actuated scattering based subsurface scanning probe microscopy

Quantitative tomography with subsurface scanning ultrasound resonance force microscopy

Mapping buried nanostructures using subsurface ultrasonic resonance force microscopy

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