Mask inspection

About: Mask inspection is a research topic. Over the lifetime, 1072 publications have been published within this topic receiving 8696 citations.

Method of manufacturing semiconductor integrated circuit device

Abstract: A method of manufacturing a semiconductor integrated circuit device, in which pattern on photomasks are transferred to a semiconductor wafer, and particularly techniques are employed for using control data, production condition data and inspection data in common in different production steps. A photomask is produced at a photomask production step by electron beam lithography. The same coordinate system of the pattern data used at the photomask production step are used in inspection/correction steps. The mask pattern of the photomask is transferred to the wafer by a step-and-repeat system. In this instance, the step movement is depending on the coordinate system of the pattern data. The wafer so exposed is then developed and etched to form repeats of reduced patterns on it, that is, this wafer pattern is composed of the reduced pattern produced by a step-and-repeat technique according to the coordinate system of the pattern data. The coordinate system of the pattern data is used to inspect the patterned wafers on a wafer tester. If a defect is found on a wafer, a detailed inspection of the corresponding photomask is carried out in a photomask inspection/correction step based on the results of the patterned wafer inspection step. Since the inspection result data comprises the coordinate system of the pattern data, it can be utilized as the data for the detailed inspection.

Method for inspection of photomask

Abstract: PURPOSE:To increase the reliability of photomask inspection by a method wherein a transparent film having film thickness of nlambda/4 (n: integral number, lambda: light- emission source wavelength) is formed in advance on a substrate, a mask pattern is reproduced on the upper surface of said transparent film, and a comparative detection is performed. CONSTITUTION:A resist film pattern 8 is reproduced on the substrate 1 using the photmask to be inspected, and a defect is detected by comparing the reflected light image coming from the two mask patterns of samd type located on the substrate. At that time, a transparent film 10 having the film thickness of nlambda/4 (n: integral number, lambda: light-emission source wavelength) is formed in advance on the substrate 1. As a result, the difference of quantity of light between the pattern 8 and the surface of the substrate 1 is increased, and a misjudgement can be eliminated even when a visual inspection is performed.

Automatic Mask Pattern Inspection For Printed Circuits Based On Pattern Width Measurement

Abstract: This is a new mask Inspection technique based on pattern width measurement that can check the fatality of defects. Mask quality depends on pattern width and defects in a fatal area where a normal pattern is seriously damage. In this technique, pattern width measurement and fatal defect detection with a laser beam are used for inspection of masks of PC boards. In order to determine the direction of measurement, diffracted laser light at the pattern edge and spatially divided photodetectors are used. The new inspection system (l) measures pattern width, (2)does not require the original data for comparison, (3)detects fatal defects, (4)has no special alignment and (5)detects defects as small as 10μm can be isolated with 100% accuracy.© (1979) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Capability of model EBEYE M for EUV mask production

Abstract: According to the ITRS Roadmap [1], within a few years the EUV mask requirement for defect will be detection of defect size of less than 25 nm. Electron Beam (EB) inspection is one of the candidates to meet such a severe defect requirement. EB inspection system, Model EBEYE M※1, has been developed for EUV mask inspection. Model EBEYE M employs Projection Electron Microscope (PEM) technique and image acquisition technique to acquire image with Time Delay Integration (TDI) sensor while the stage moves continuously [2]. Therefore, Model EBEYE M has high performance in terms of sensitivity, throughput and cost. In a previous study, we showed the performance of Model EBEYE M for 2X nm in a development phase whose sensitivity in pattern inspection was around 20 nm and in particle inspection was 20 nm with throughput of 2 hours in 100 mm square [3], [4]. With regard to pattern inspection, Model EBEYE M for High Volume Manufacturing (HVM) is currently under development in the production phase. With regard to particle inspection, Model EBEYE M for 2X nm is currently progressing from the development phase to the production phase. In this paper, the particle inspection performance of Model EBEYE M for 2X nm in the production phase was evaluated. Capture rate and repeatability were used for evaluating productivity. The target set was 100% capture rate of 20 nm. 100% repeatability of 20 nm with 3 inspection runs was also set as a target. Moreover, throughput of 1 hour in 100 mm square, which was higher than for Model EBEYE M for 2X nm in the development phase, was set as a target. To meet these targets, electron optical conditions were optimized by evaluating the Signal-to-Noise Ratio (SNR). As a result, SNR of 30 nm PSL was improved 2.5 times. And the capture rate of 20 nm was improved from 21% with throughput of 2 hours to 100% with throughput of 1 hour. Moreover, the repeatability of 20 nm with 3 inspection runs was 100% with throughput of 1 hour. From these results, we confirmed that Model EBEYE M particle inspection mode could be available for EUV mask production.