Development of a Digital-Convolution-Based Process Emulator for Three-Dimensional Microstructure Fabrication Using Electron-Beam Lithography

Although electron-beam lithography has been demonstrated to be feasible in creating 3-D micropolymer structures, the proximity effect due to forward and backward scatterings usually makes it difficult to precisely determine the distribution of electron irradiation. The process design for creating the desired shape still largely depends on a trial-and-error basis. Therefore, in order to reduce the cost and to accelerate product development, it is important to utilize computer-aided design tools. A method, called as element growth method, which is based on digital convolution approach, is developed and presented under an OpenGL environment to reduce the cost and the developmental period for fabrication. By using such a convolution approach, this emulator converts the processing parameters into a final spatial-dosage distribution and subsequently into the final geometry of structures. In addition, a physically based kernel function is also proposed and used. Examples of 3-D microstructures such as the microlens are presented. By these tools, it is possible to provide guidelines for optimizing the fabrication process and to reduce the cost for the related e-beam lithography-based 3-D fabrication.