Direct Imaging of Integrated Circuits in CPU with 60 nm Super-Resolution Optical Microscope

Abstract

Far-field super-resolution optical microscopies have achieved incredible success in life science for visualization of vital nanostructures organized in single cells. However, such resolution power has been much less extended to material science for inspection of human-made ultrafine nanostructures, simply because the current super-resolution optical microscopies modalities are rarely applicable to nonfluorescent samples or unlabeled systems. Here, we report an antiphase demodulation pump–probe (DPP) super-resolution microscope for direct optical inspection of integrated circuits (ICs) with a lateral resolution down to 60 nm. Because of the strong pump–probe (PP) signal from copper, we performed label-free super-resolution imaging of multilayered copper interconnects on a small central processing unit (CPU) chip. The label-free super-resolution DPP optical microscopy opens possibilities for easy, fast, and large-scale electronic inspection in the whole pipeline chain for designing and manufacturing ICs.

Far-field super-resolution chemical microscopy

“…d Antiphase demodulation transient absorption microscopy. Reproduced with permission 51 . Copyright 2021 American Chemical Society.…”

“…To achieve super-resolution imaging of interweaved copper wires, Yang et al 51 impressed an additional pump laser in a donut shape with antiphase modulation and thus form a modulated subdiffraction-limit focus center in the laser focus, as shown in Fig. 3d .…”

“…For electronic-state transient absorption microscopy, the depletion effect, nonlinearity, and structured illumination are applied to realize a much higher resolution. These methods lead to the development of STED-TA 48 – 51 , Nonlinear differential TA 52 , and SI-TA 53 .…”

Sub-50 nm optical imaging in ambient air with 10× objective lens enabled by hyper-hemi-microsphere

“…In the manufacturing processes of semiconductor chips, the direct inspection of chips is essential for quality control. To discern sub-100 nm features on chips, many tools including scanning electron microscope, atomic force microscope and ptychographic X-ray computed tomography are implemented 2 . However, they have limitations including the requirement of vacuum environment, time-consuming sample preparation and expensive synchrotron radiation source, which is usually not accessible for broad applications.…”

Stimulated Raman versus Inverse Raman: Investigating Depletion Mechanisms for Super-Resolution Raman Microscopy

“…Recent advances have been made toward label-free super-resolution microscopy, making use of intrinsic vibrational and electronic transitions in biological samples. − The development of photothermal IR (PTIR) has made it possible to image IR-active vibrational modes with the spatial resolution of visible light microscopy. − However, PTIR is still limited by the diffraction limit for visible light, making sub-100 nm resolutions impossible in its current form. Transient absorption microscopy (TAM), also known as pump–probe microscopy (PPM), has also been adapted to achieve subdiffraction limited resolution. , Two TAM methods in particular, saturated PPM and demodulated PPM (DPPM), both use toroidally shaped beams through different applications to achieve resolution below 100 nm. − To date, super-resolution TAM requires strong and distinct absorption features, which are not present in many biological samples …”