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Mask critical dimension (CD) errors are analyzed in case fogging effect is corrected by dose modulation method with comparison of measurement and simulation. In the test mask, an extreme condition from pattern density 0% to 100% is applied for making fogging effect. On the ground of the utmost pattern densities which is one of the factors of fogging effect, various mask CD errors are observed with optical measurement in spite of fogging correction. Each error factor is distinguished from whole mask error using electron beam simulator which is adopting Monte Carlo (MC) calculation for electron scattering modeling, proximity effect correction (PEC) and even fogging effect correction. From error analysis, 3 kinds of mask error are observed. The first CD error is from an inaccurate modeling of fogging effect, the second is from fogging correction program. The third is error from development loading effect. The two formers are comparatively less important than the latter because they can be soluble problems by careful selection of fogging model or improvement of computing systems. However, error from develop loading effect is hard to solve so that not only chemical but also fluid mechanical approach is needed.

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Verification of full-chip DSA guide patterns (GPs) through simulations is not practical due to long runtime. We develop a decision function (or functions), which receives n geometry parameters of a GP as inputs and predicts whether the GP faithfully produces desired contacts (good) or not (bad). We take a few sample GPs to construct the function; DSA simulations are performed for each GP to decide whether it is good or bad, and the decision is marked in n-dimensional space. The hyper-plane that separates good marks and bad marks in that space is determined through machine learning process, and corresponds to our decision function. We try a single global function that can be applied to any GP types, and a series of functions in which each function is customized for different GP type; they are then compared and assessed in 10nm technology.