Uniform chemical etching method
AssigneeS.O.I.Tec Silicon on Insulator Technologies
InventorCêcile Delattre
Life of this patent
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Abstract
The invention concerns a method of wet chemical etching of a wafer comprising at least one surface layer of silicon-germanium (SiGe) for etching by dispensing an etching solution deposited on a rotating wafer, the method being characterized in that it comprises a first etching step in which said etching solution is dispensed from a fixed position located at a predetermined distance from the center of the wafer, and a second etching step in which the etching solution is dispensed radially from the center of the wafer and over a maximum distance which is less than the radius of said wafer.
Claims15
A method of wet chemical etching of a rotating wafer comprising at least one surface layer of silicon-germanium (SiGe) which is to be etched, the method comprising:
- a first etching step in which an etching solution is dispensed onto said wafer from a fixed position located at a certain distance from the center of said wafer, and
- a second etching step in which said etching solution is dispensed onto said wafer while in motion along a radial path from a position varying from the center of said wafer to a maximum distance which is less than the certain distance of said wafer.
A method of wet chemical etching of a rotating wafer comprising at least one surface layer of silicon-germanium (SiGe) which is to be etched, the method comprising:
- a first etching step in which an etching solution is dispensed onto said wafer from a fixed position located at a certain distance from the center of said wafer;
- a second etching step in which said etching solution is dispensed onto said wafer while in motion along a radial path from a position varying from the center of said wafer to a maximum distance which is less than the certain distance of said wafer;
- and
- chemical-mechanical polishing of the SiGe surface layer carried out prior to said first and second etching steps, and wherein the first etching step conducted for a period that is shorter than that conducted for the second etching step.
A method of wet chemical etching of a rotating wafer comprising:
- a first dispensing step for dispensing etching solution from a fixed position onto said wafer away from the center of said wafer so that etching occurs preferentially at the edge of said wafer;
- and
- a second dispensing step for dispensing etching solution from a moving position onto said wafer near the center of said wafer so that etching occurs preferentially at the center of said wafer;
- wherein the first and second dispensing steps are conducted so that etching is substantially uniform across the entire wafer.
Dependencies are inferred from the claim text.