Effect of temperature on the etching rate of nitride and oxide layer using Buffered Oxide Etch

This paper presents the effect of temperature to the etch rate of nitride and oxide layers in Buffered Oxide Etch (BOE) solution. Either nitride or oxide layer is commonly used in the semiconductor fabrication process as a mask for the next wet etching process. A well-defined frame structure and reduced etching time will increase the productivity of the fabrication process. The approach starts with patterning the silicon nitride to study the frame structure that formed after the BOE process. Then, the patterned silicon nitride is dipped in BOE solution at two different temperatures, which are 25 °C and 80 °C. The structures that formed are compared, and it was evident that 80 °C gives a better mask structure. Next, the effect of temperature on the etching rate for oxide and nitride layers is further studied by varying the temperature from 40 °C up to 90 °C. At the end of experiment, it was found that temperature will improve the BOE etching process in terms of both time needed and the mask structure.