WAFER CLEANING MACHINE FOR TOPOGRAPHIC SUBSTRATES
Original Publication Date: 1997-Jun-30
Included in the Prior Art Database: 2004-Apr-08
Xerox Disclosure Journal
Disclosed is a method and apparatus for cleaning micro-electromechanical die modules having planarized thick film layers. The planarization process uses a slurry which tends to remain behind and becomes trapped in heater pits. To remove the remaining slurry, an improved cleaning unit comprising two counter-rotating sponge rollers which are positioned above a manual or servo movable table below. The sponge surface is made of, for example, polyvinyl alcohol. The sponges are preferably softened with water from a continuous drip assembly mounted over the length of the sponge rollers. The sponge members are rubbed over the wafer surface without damaging the etched patterns formed thereon. Chemicals, such as surfactants, can be optionally included in the water of the drip assembly to further aid in the slurry removal. The movable table allows the entire wafer to be pushed back and forth under the sponges and the slurry is brushed out from the pits. The continuously dipping water also helps to flush away the slurry liberated from the pits. In automated manufacturing embodiments, a vacuum conveyor belt or other robotic wafer transporting system can be used to move the wafers from cassettes to the scrubber rollers in a stepwise or continuous fashion. The apparatus and the method enable significant amounts of slurry to be removed form deep topographic patterns without the use of any surfactant if desired, and is particularly important in polishing operations where surfactant contamination can be a signifcant issue. In thermal ink jet applications, it is known that "dirt" on heaters can cause banding problems in print quality. It is also known that "dirt" on the heater can affect thermal ink jet drop nucleation. The double roller scrubber cleaning system allows slurry to be scrubbed out of pits in several directions so that the slurry does not get pushed up against any topographic feature.