Articles you may be interested inFocused helium and neon ion beam induced etching for advanced extreme ultraviolet lithography mask repair Testing new chemistries for mask repair with focused ion beam gas assisted etching With continuous reduction in linewidth of the VLSI devices, the pattern integrity of photomasks becomes considerably more important than ever. Consequently, requirement for the defect repair technology on photomasks is more severe and strict. Focused ion beam ͑FIB͒ technology has been widely used for defect repairing in photomask industry. Therefore, the performance of the FIB mask repair tool has to be improved especially in repair accuracy and precision. The FIB repair processes are classified into two kinds; one is additive repair using FIB induced deposition for missing patterns, the other is subtractive repair using gas assisted FIB etching for extra patterns. In both processes, precursor gas is applied onto the processing area through a small nozzle. Thus, the repair processes are controlled by the FIB irradiation and the precursor gas supply. Important characteristics of the repairs, such as size, shape, and placement of the repair area, are defined by the FIB scanning control. As conventional FIB systems used raster type of beam scanning for the repair processes, the size, shape, and placement could be controlled with the unit of pixel size ͑typically about 6 -12 nm͒. However, in order to satisfy the recent requirement, more precise beam control is needed. The authors have developed a vector scanning system to meet the requirement. The vector scanning system enables us to control ion beams more precisely and more arbitrarily. Furthermore, unicursal beam scanning can be applied to the repair processes, which minimizes beam blanking times. By adopting the vector scanning, repair precision is improved. Additionally, sidewall angle of the repair region is also improved because the repair shape is formed without beam blanking.

Testing new chemistries for mask repair with focused ion beam gas assisted etchingFocused ion beam ͑FIB͒ technology has widely been adopted as a defect repair tool on photomasks for semiconductor manufacturing. In the FIB mask repair process, scanning ion image ͑FIB image͒ is used for the defect area recognition. Quality of the FIB images is one of the most important factors in order to improve the repair accuracy. Precise imaging of the small features on the photomasks, however, is a challenging subject due to the surface charge buildup induced by FIB scanning, even though simultaneous electron beam irradiation is used for the charge compensation. The authors have developed new method of the FIB scanning for better image quality. This method utilizes software accumulation of multiple images with different scan directions and results in higher peak-to-background ratio and higher contrast images with isolated mask patterns on the quartz substrate, compared to the images acquired from conventional single scanning. The images also show better uniformity and symmetry of the secondary electron intensity.

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The satisfactory data have been confirmed on the photomask repairing performance for 100nm-node/ArF-generation lithography with the model SIR5000 photomask repair system. In this report, the repairing ability is presented with transmittance and edge placement data. The edge placement was almost 15nm(3sigma) on binary and MoSi-HT masks, and there isn't any transmittance loss in the AIMS193 data.