{'fraction_non_alphanumeric': 0.018880208333333332, 'fraction_numerical': 0.007161458333333333, 'mean_word_length': 5.540425531914893, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Submicron calibration strategy for CD control

In the modern semiconductor processing facility CD (critical dimension) measurements on 200-mm diameter wafers proceed in a fully automated mode requiring only wafer loading, measurement recipe loading, and a 'run' command for processing. To provide effective metrology support to this facility the scope of CD measurement automation has been extended to the entire metrology scheme, from job file generation to CD measurement and data collection. Upon completion of all sample measurements, data is uploaded to the factory's data collection software system via a SECS II interface, eliminating the requirement of manual data entry. This paper presents the methodology used to perform calibration of the automated CD metrology scanning electron microscope (SEM) for sub-0.5 micrometer process control. A commercially available SEM pitch standard, traceable to JQA (Japan Quality Assurance) has been characterized and incorporated into a standard, automated calibration procedure performed as part of the regular tool qualification. This standard contains lines with pitch on order of 0.240 micrometer over a 4 mm2 area and is useful at low accelerating voltage. Since the low accelerating voltage CD measurement SEM has assumed an important role in modern semiconductor process control, we investigate the use and performance of the standard in a representative instrument. Evaluation of this reference by SEM CD measurements shows suitable performance for submicron dimension calibration.