2. a) Inductively-coupled RF plasma (ICP) systems are often used to etch silicon wafers in the...

 

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2. a) Inductively-coupled RF plasma (ICP) systems are often used to etch silicon wafers in the manufacture of microelectronics. These systems utilize external coils as electrodes. i) ii) Explain briefly the fundamental principles of induction, which can lead to the creation of dense plasma away from the coil. Include in your answer a suitable diagram showing the relevant EM fields. Draw a sketch of two ICP designs that employ different geometries for the external coils. Include in your sketch, the chamber walls and the wafer substrates. Label all the important features. In many silicon etching applications CF4 is used as an etchant, however an engineer decides to use CCl4 instead. iii) Write down the main plasma-chemical reactions involving the bombardment of CCl4 by electrons. iv) Which species created in the plasma would be responsible for isotropic etching of the silicon and which would be responsible for anisotropic etching? 2. a) Inductively-coupled RF plasma (ICP) systems are often used to etch silicon wafers in the manufacture of microelectronics. These systems utilize external coils as electrodes. i) ii) Explain briefly the fundamental principles of induction, which can lead to the creation of dense plasma away from the coil. Include in your answer a suitable diagram showing the relevant EM fields. Draw a sketch of two ICP designs that employ different geometries for the external coils. Include in your sketch, the chamber walls and the wafer substrates. Label all the important features. In many silicon etching applications CF4 is used as an etchant, however an engineer decides to use CCl4 instead. iii) Write down the main plasma-chemical reactions involving the bombardment of CCl4 by electrons. iv) Which species created in the plasma would be responsible for isotropic etching of the silicon and which would be responsible for anisotropic etching?