In turn, the photoresist hardens in desired patterns when it is developed. During the etching process, wafers are moved to a plasma reactor where electrically excited gases etch the surface into the pattern defined by the photolithography process. After etching, wafers are cleaned thoroughly. Toward final wafer fabrication, each wafer is subjected to testing to determine defective components. Silicon nitride, a protective coating, is applied.
Wafers are then ready for the final processing step, multiprobe testing.
Each integrated circuit in the wafer is electrically tested to determine whether or not a chip is ready for final assembly, bonding and packaging. 1985 Most inventions, like the loom and the steam engine, are labor-saving devices. They free people from the limitations of their own strength. Other inventions, like the telescope, improve people's ability to comprehend their universe. They extend the senses.