Study Of DRAM Theory And Process Flow

The requirement for semiconductor technology is increasing rapidly with technological information developing quickly.DRAM (Dynamic Random Access Memory) is applied broadly due to its higher integration density, lower cost, smaller volume and lower power consumer. Demand drives technical progress. Recently DRAM makes fast technical reform which including access speed increasing, memory capability increasing, cell array densify and cell cost down. Therefore, the technology of DRAM is becoming the advanced guideline for semiconductor technology.However, the architecture of basic memory cell is not changed too much since 4K DRAM change to be one cell transistor plus one capacitor. This paper is just based on the 1T/1C that basic memory cell to describe how to make DRAM and achieve data storage, reading and writing. Besides emphasis on description how to achieve for capacitor control and retention time decreasing by semiconductor fabrication integration process improvement. In this paper described two kinds of approaches that applied broadly for storage capacitor architecture and fabrication process which are trench capacitor approach and stack capacitor approach and point out their technical advantage and technical difficulty. It introduced some core technology developing way, for example, HSG technology, BST dielectric technology, leakage control technology and so on, that has semiconductor forecast. Besides, this paper has combined with some issue in my daily working, which described the practical example in semiconductor process improvement, provided issue description, issued analysis and issue solution methodology.