Microelectronic devices are formed by first forming Si02 on a silicon wafer by chemical va...

Microelectronic devices are formed by first forming Si02 on a silicon wafer by chemical vapor deposition (Figure PS-13B). This procedure is followed by coating the Si02 with a polymer called a photoresist. The pattern of the electronic circuit is then placed on the polymer and the sample is irradiated with ultraviolet light. If the polymer is a positive photoresist, the sections that were irradiated will dissolve in the appropriate solvent, and those sections not irradiated will protect the Si02 from further treatment. The wafer is then exposed to strong acids, such as HF, which etch (i.e., dissolve) the exposed Si02 . It is extremely important to know the kinetics of the reaction so that the proper depth of the channel can be achieved. The dissolution reaction is  

From the following initial rate data, determine the rate law.

A total of 1000 thin wafer chips are to be placed in 0.5 dm3 of 20% HF. If a spiral channel 10 µm wide and 10 m in length were to be etched to a depth of 50 µm on both sides of each wafer, how long should the chips be left in the solution? Assume that the solution is well mixed.

  Semiconductor Etching