Microsphere-assisted hyperspectral imaging:super-resolution,non-destructive metrology for semiconductor devices

As semiconductor devices shrink and their manufacturing processes advance,accurately measuring in-cell critical dimensions(CD)becomes increasingly crucial.Traditional test element group(TEG)measurements are becoming inadequate for representing the fine,repetitive patterns in cell blocks.Conventional non-destructive metrology technologies like optical critical dimension(OCD)are limited due to their large spot diameter of approximately 25μm,which impedes their efficacy for detailed in-cell structural analysis.Consequently,there is a pressing need for small-spot and non-destructive metrology methods.To address this limitation,we demonstrate a microsphere-assisted hyperspectral imaging(MAHSI)system,specifically designed for small spot optical metrology with super-resolution.Utilizing microsphere-assisted super-resolution imaging,this system achieves an optical resolution of 66 nm within a field of view of 5.6μm×5.6μm.This approach effectively breaks the diffraction limit,significantly enhancing the magnification of the system.The MAHSI system incorporating hyperspectral imaging with a wavelength range of 400–790 nm,enables the capture of the reflection spectrum at each camera pixel.The achieved pixel resolution,which is equivalent to the measuring spot size,is 14.4 nm/pixel and the magnification is 450X.The MAHSI system enables measurement of local uniformity in critical areas like corners and edges of DRAM cell blocks,areas previously challenging to inspect with conventional OCD methods.To our knowledge,this approach represents the first global implementation of microsphere-assisted hyperspectral imaging to address the metrology challenges in complex 3D structures of semiconductor devices.

Clinical outcomes of angiosarcoma:a single institution experience

Dear Editor,Angiosarcoma is a rare malignancy,which accounts for approximately 1%-2%of soft-tissue sarcomas[1].It can occur at any site within the human body.Some research-ers suggested that site distribution may be different between Eastern Asian and Western countries[1].Sev-eral factors,such as age,stage at diagnosis,performance status,site of the disease,histological grade,tumor size,and visceral involvement,were suggested as prognos-tic factors in angiosarcoma[2-5].However,there is still controversy regarding to which prognostic factors are significantly important.As there are no randomized clinical trials for angiosarcoma,its treatments are guided based on guidelines of soft-tissue sarcoma or the results of several retrospective studies.Radical surgery is the preferred treatment for angiosarcoma[2-4].Some stud-ies suggested that receiving adjuvant chemotherapy(CT)is associated with better outcome[5],while other studies have shown that adjuvant CT has no significant effect[6,7].Chemoradiotherapy has been reported to be effective in angiosarcoma especially for cutaneous angiosarcoma[8].However,evidence for the efficacy and safety of pal-liative cytotoxic CT is still limited.Therefore,here,we present our analysis based on the clinical features,tumor characteristics,treatment and outcomes of angiosarcoma patients in an attempt to investigate the significant prog-nostic factors and efficient therapeutics in real clinical practice.