Upside-Down Resist Coating of Semiconductor Wafers
Original Publication Date: 1989-Jun-01
Included in the Prior Art Database: 2005-Jan-28
Presently, wafers are coated with resist from the top, with the wafer being stationary in a horizontal position or spinning at a given number of revolutions (dynamic coating). It is essential with this type of coating that any "resist puddles" are evenly spread and that the wafer is uniformly covered (which requires a lavish minimum quantity of resist) before any excess resist is spun off and the desired layer thickness is obtained. With this kind of coating, about 99% of the valuable resist are wasted, not to mention the fact that such waste is difficult to dispose of.