すきま理論に基づくラッピングシミュレーション（第2報）: 小型工具による揺動ラッピング

摘要

フラットパネルディスプレイに使用されるマザーガラスやそのrnリソグラフィ工程に使用されるマスク基板は大型化が進み，それrnぞれ2．85×3.05m，1.22m×1.4mの基板の使用が計画されている．rnまた，マスク基板には，現在，数10μm以下の高い平坦度が要求さrnれているが，近い将兎その値はさらに厳しい10μm以下になるとrn言われている．%The simulation of lapping to correct the surface profile of a workpiece has been made very little study. In contrast, the simulation of polishing has been developed using the gap theory and it has been demonstrated that there is good agreement between simulated and experimental results. Our study investigates the application of polishing simulation to lapping. We have reported that a lapped profile can be calculated if a suitable value of relative elastic coefficient is used. This paper describes workpiece and tool profiles lapped with a small tool, and corresponding simulation results calculated using the gap theory, for oscillation lapping to planarize a quartz glass wafer. Under non-oscillation conditions, the experimental results for workpiece and tool profiles correspond roughly with simulated results. When the tool overhangs the workpiece, to a significant extent, the experimental results do not correspond with the simulated ones. Therefore, the slope of the pressure distribution for the simulation was adjusted to increase rapidly when the amount of overhang is more than 30 % of tool diameter. As a result, the experimental and simulation results corresponded very closely. In uniform-oscillation-speed lapping, it was demonstrated that the achieved workpiece and tool profiles coincide approximately with the results of the simulation.