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Method for Providing Multiple and Definable Current Source to a Plating Cathode and n-deflectors from a Single Current Source

IP.com Disclosure Number: IPCOM000013345D
Original Publication Date: 2000-Aug-01
Included in the Prior Art Database: 2003-Jun-18
Document File: 1 page(s) / 28K

Publishing Venue

IBM

Abstract

A method for providing multiple and definable current sources to a plating

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  Method for Providing Multiple and Definable Current Source to a Plating Cathode and n-deflectors from a Single Current Source

   A method for providing multiple and definable current sources to a plating
cathode and n-deflectors from a single current source.

Problems solved by this invention include:

1. A plating system can be built with less power supplies and less channels.
2. Only one wire is needed from a single current source to a cathode and
n-deflectors.

   3. Wiring and packaging is simplified for delivering current to the cathode
and n-deflectors.

4. Less power supplies and channels are needed for a plating station.
5. Current to the wafer and segmented deflectors can be programmed for optimum
plating uniformities.

A well known problem in electroplating processes are the "edge effects" where
thickness uniformities are either too thick or too thin because current density
at the periphery of the workpiece is not the same as at the inner portions. A
method for compensating for this effect is to have segmented deflectors (thiefs)
surrounding the circumference of the wafer and driving high current to the
adjacent deflector when the edge of the wafer is plating high and driving the
current low or no current when the edge of the wafer is plating thin.

This invention provides for a single current sorce or power supply, utilizing a
current divider from the source to the wafer and n-deflectors through the
equivalent of a programmable current divider network. The programming current t...