Proximity Effect Correction for Mask Writing Taking Resist Development Processes into Account

In this paper, a proximity effect correction method for mask fabrication with taking into account resist development processes is proposed. The idea of our method is that the figure size of a developed resist is determined using a suitable function of exposure dose and the normalized deposited energy by backscattering electrons, under the assumption of high acceleration voltage electron beam mask writing. This suitable function should be determined empirically to include the effects of resist development process, and is called development process function in this paper. Methods of deriving the development process function, proximity effect correction equation, and optimum correction dose from the equation are proposed. To check the accuracy of our method, a sample model of development process function is introduced under the condition that the conventional threshold model has an intrinsic error of 8 nm. The method proposed in this paper is found to be able to suppress the correction error of this sample model to less than 1 and 0.2 nm by two and three iterations, respectively. The method proposed in this paper is expected to provide high accuracy proximity effect correction in future mask fabrication.