Analysis of microloading effects on SiO2 etching using ECR plasma; ECR plasma wo mochiita SiO2 no etching ni okeru microloading koka no kaiseki

An experiment has discovered a phenomenon that may resolve the problem of microloading effect in the semiconductor device fabrication process. Discussions were carried out by using a new model. Reverse microloading that can improve the microloading effect occurs characteristically when a gas is used that has high C/F ratio and high deposition velocity in a low-pressure high-density plasma. The microloading effect is caused from shortage of flux associated with high aspect ratio of the hole. In the reverse-microloading, an experiment and a simulation indicated that sufficient ions reach the hole bottom as a result of pressure reduction and bias application, and a fluorocarbon film with high deposition velocity impedes the etching. According to the simulation result, performing deep submicron hole etching requires better control of the ion directions. It was shown that the use of a gas with low deposition velocity is better in improving the reverse microloading. 9 refs., 12 figs.