Point-of-use Generation And Recycle Of High Purity Wafer Cleaning Chemicals

The cleaning chemicals presently used in the production of ultra large scale integrated (ULSI) circuits pose two major problems. The chemicals contain impurity levels that decrease the manufacutring yield of the circuits. In addition, they require extensive treatment for safe disposal. The process described in this proposal addresses regenerated to produce high purity chemicals. The process is applicalbe to the on-site, Point-of-Use regeneration of hydrodlouric acid (HF), hydrochloric acid (HC1) and ammonium hydroxide. Regeneration of these chemicals is accomplished using a combination of distillation and absorption. Distillation is used to separate the chemicals from process generated contaminants. Absorption into high purity deionized (DI) water is used to reconstitute the chemicals. The process is expected to produce chemicals with impurity levels well below those of commercially available chemicals. HF and HC1 cannot be distilled directly from the spent chemical solutions as they form azeotropes with water. A proprietary method is employed to break the azeotrope without decreasing the purity of the recovered chemicals or creating a disposal problem. ANTICIPATED BENEFITS: Successful completion of this project is expected to yield a process which increases the manufacturing yield of ULSI circuits and reduces their manufacturing cost. Use of the process will make the US semiconductor industry more competitive with foreign competitive.