On Mask Fabrication Using an Optical Pattern Generator in the Direct Data Entry Mode

Abstract

Mask making is very important for integrated circuit fabrication. The general trend in semiconductor devices development has been towards diminishing dimensions and higher component density of integrated circuits. Therefore, a mask making system has to fulfil these requirements. Automatic optical pattern generation has been the dominant trend in the semiconductor industry. The quality of the masks produced can be improved if proper exposure and subsequent processing methods are used. The CEERI Electromask optical Pattern Generator/Image Repeater-combination system is being used to expose a variety of single devices such as microwave diodes and transistors, complex devices such as MOS integrated circuits. Traditionally, a computer-aided design system is needed to transfer design data into flash data for a pattern generator. This method is essential for integrated circuits. However, there are several single devices, especially in the microwave region, where state-of-the-art feature sizes are required. For such cases, it is possible to use the pattern generator in direct data entry mode where the use of a computer-aided design system is not needed. In this paper, we present an account of masks made using the Electromask pattern generator in its direct-data-entry mode. It has been shown that in a research type of environment, it is possible to make high quality masks for discrete devices, without the use of a computer-aided design system.