US Patent 7497885 - Nanoparticle abrasive

http://www.freepatentsonline.com/7497885.html

In many semiconductor device manufacturing steps it is necessary to have a uniformly flat surface to work with after processing of a silicon wafer. One technique to achieve such flat surfaces is called chemical mechanical planarization. This patent from 3M teaches using nanoparticulate abrasives to enhance this type of planarization process. Claim 1 reads:

1. A fixed abrasive article comprising:

a plurality of three-dimensional abrasive composites fixed to the abrasive article,

wherein the abrasive composites comprise a plurality of abrasive particles having a volume mean diameter less than 500 nanometers (nm) in a matrix material,

the matrix material comprising a polymeric binder and a plurality of inorganic filler particles having a volume mean diameter no greater than 200 nanometers.