Process tolerances for critical dimensions are becoming increasingly severe as lithographic technology drives the minimum integrated-circuit feature size toward 0.1 µm and below. In response, Optical Critical Dimension metrology (OCD), an optical-wavelength light-diffraction technique, is currently undergoing an industry-wide evaluation as a fast, accurate, and non-destructive sub-100nm line-width monitor. As such, a detailed understanding of the correlation between CD-SEM and OCD measurements is required. Correlation between CD measurements using these two techniques is investigated by measuring photo-resist gratings on a polysilicon gate film stack. Intra-grating CD variation is shown to account for scatter in the correlation plot. Correlation between CD-SEM and OCD measurements is also demonstrated for samples with three different pitch sizes. A qualitative line-profile correlation between cross-section SEM (X-SEM) and OCD is presented for photoresist gratings in a Focus Exposure Matrix (FEM).
Brain metastases generally present in the parenchyma of the brain. In the current report, a very rare case of brain metastasis, which simultaneously invaded the subgaleal region, the skull, and the dural and cavernous sinuses is presented. The patient, a 54-year-old female, complained of a progressive headache and exhibited the symptoms of intracranial hypertension. Coronal contrast-enhanced T1-weighted magnetic resonance imaging (MRI) showed high intensity signals in the subgaleal tissue of the left frontoparietal area, as well as in the dural and the cavernous sinuses. The patient was initially diagnosed with an intracranial infection, however, the administered treatment was ineffective. The patient subsequently underwent a biopsy and the pathological diagnosis was determined as a metastatic adenocarcinoma; a primary tumor was not identified during the examinations. Surgical removal of certain metastases and a decompressive craniectomy were performed to relieve the intracranial hypertension. However, the prognosis was unsatisfactory. The patient’s neurological condition progressively worsened and an axial computed tomography scan with a bone window demonstrated a bulging growth in the brain tissue. The patient succumbed after one month due to the widespread metastasis. Thus, this case presents the unusual clinical development of this type of metastatic adenocarcinoma. In addition, due to the intracranial hypertension, the unusual sites of the high intensity signals in the MRI and the lack of a primary tumor, the patient was misdiagnosed with an intracranial infection. Furthermore, this case highlights the necessity for conducting a biopsy as soon as possible and demonstrates the poor prognosis associated with this type of patient.
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