The production of electronics involves several steps that use chemicals. The first step is the manufacturing of semiconductor wafers, for which chemicals (e.g., TEOS, tetraethyl orthosilicate) of very high purity are needed. The next step is the fabrication of chips, which requires the use of chemicals such as acids and solvents for etching and cleaning. The assembly of components involves the use of adhesives, soldering flux, and surface treatment chemicals. The final step of testing and quality control also involves the use of chemicals for testing the electrical properties of the components.