Masked ion implant with fast-slow scan
AssigneeVarian Semiconductor Equipment Associates, Inc.
InventorsNicholas P. T. Bateman, Steven M. Anella, Benjamin B. Riordon, Atul Gupta
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Abstract
An improved method of producing solar cells utilizes a mask which is fixed relative to an ion beam in an ion implanter. The ion beam is directed through a plurality of apertures in the mask toward a substrate. The substrate is moved at different speeds such that the substrate is exposed to an ion dose rate when the substrate is moved at a first scan rate and to a second ion dose rate when the substrate is moved at a second scan rate. By modifying the scan rate, various dose rates may be implanted on the substrate at corresponding substrate locations. This allows ion implantation to be used to provide precise doping profiles advantageous for manufacturing solar cells.
Claims14
A method of implanting ions into a solar cell substrate comprising:
- directing an ion beam through an aperture of a shadow mask toward a substrate support configured to support a substrate;
- exposing a first portion of said substrate, aligned with said aperture of said shadow mask, to said ion beam;
- moving said substrate support with respect to said ion beam at a first scan rate when said first portion of said substrate is exposed to the ion beam;
- exposing a second portion of said substrate, aligned with said aperture of said shadow mask, to said ion beam;
- and
- moving said substrate support with respect to said ion beam at a second scan rate when said second portion of said substrate is exposed to said ion beam, wherein said first scan rate is slower than said second scan rate.
A method of implanting ions into a substrate comprising:
- directing an ion beam through a plurality of apertures of a shadow mask toward a substrate support configured to support a substrate;
- exposing first portions of said substrate to said ion beam corresponding to said plurality of apertures of said shadow mask;
- moving said substrate support with respect to said ion beam at a first rate when said first portions of said substrate are exposed to said ion beam;
- exposing second portions of said substrate to said ion beam corresponding to said plurality of apertures of said shadow mask;
- and
- moving said substrate support with respect to said ion beam at a second rate when said second portions of said substrate are exposed to said ion beam, wherein said first scan rate is faster than said second scan rate.
Dependencies are inferred from the claim text.