Equipment
A typical (parallel plate) RIE system consists of a cylindrical vacuum chamber, with a wafer platter situated in the bottom portion of the chamber. The wafer platter is electrically isolated from the rest of the chamber, which is usually grounded. Gas enters through small inlets in the top of the chamber, and exits to the vacuum pump system through the bottom. The types and amount of gas used vary depending upon the etch process; for instance, sulfur hexafluoride is commonly used for etching silicon. Gas pressure is typically maintained in a range between a few millitorr and a few hundred millitorr by adjusting gas flow rates and/or adjusting an exhaust orifice.
Other types of RIE systems exist, including inductively coupled plasma (ICP) RIE. In this type of system, the plasma is generated with an RF powered magnetic field. Very high plasma densities can be achieved, though etch profiles tend to be more isotropic.
A combination of parallel plate and inductively coupled plasma RIE is possible. In this system, the ICP is employed as a high density source of ions which increases the etch rate, whereas a separate RF bias is applied to the substrate (silicon wafer) to create directional electric fields near the substrate to achieve more anisotropic etch profiles.
Read more about this topic: Reactive-ion Etching
Famous quotes containing the word equipment:
“Pop artists deal with the lowly trivia of possessions and equipment that the present generation is lugging along with it on its safari into the future.”
—J.G. (James Graham)
“Dr. Scofield’s equipment, which you have just seen, radiated waves direct to Professor Houghland’s laboratory. When these waves came in contact with those the professor’s equipment was radiating, they created the interstellar frequency, which is the death ray.”
—Joseph O’Donnell, and Clifford Sanforth. Arthur Perry (Bela Lugosi)
“Why not draft executive and management brains to prepare and produce the equipment the $21-a-month draftee must use and forget this dollar-a-year tommyrot? Would we send an army into the field under a dollar-a-year General who had to be home Mondays, Wednesdays and Fridays?”
—Lyndon Baines Johnson (1908–1973)