Removal of Colloidal Silicon From Hydrofluoric Acid
Original Publication Date: 1987-Nov-01
Included in the Prior Art Database: 2005-Feb-02
This technique allows chemical removal of colloidal SiF6-- from HF, which colloids can impair semiconductor manufacturability by obstructing open Si contacts. A significant concern in the use of wet chemical processing in semiconductor manufacturing is the removal of particulates and chemical contaminants from the process solutions. In particular, colloidal fluorosilicic acid (H2SiF6) in hydrofluoric acid (HF) becomes critical as device geometries reach 1 micron and below. HF is typically used to remove SiO2 and expose bare Si contact areas for subsequent processing. The exposed Si is very chemically active and will adsorb the charged colloidal species. Removal of the colloids by rinsing is very difficult, and subsequent chemical removal may be required, although such is undesirable in most hot process precleaning schemes.