Controlled induction by use of power supply trigger in electrochemical processing
AssigneeNovellus Systems, Inc.
InventorsJon Henri, John Floyd Ostrowski
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Abstract
Methods and apparatus are used for triggering and controlling an initial induction period in which a substrate is immersed in an electrochemical bath prior to actual electrochemical processing. This is accomplished by sensing a change in cell potential upon immersion of the substrate or a counter electrode in an electrochemical bath. Appropriate logic then holds the cell potential or current at a fixed value for a defined delay period. After that period ends, the logic allows the cell potential or current to increase to a level where electrochemical processing begins.
Claims19
A method of controlling the induction period of a substrate in an electrolytic solution prior to electrochemical processing, the method comprising:
- (a) applying an entry voltage to the substrate or a counter electrode prior to immersing the substrate or counter electrode in the electrolytic solution;
- (b) immersing the substrate or counter electrode in the electrolytic solution while the entry voltage is applied;
- (c) determining that the entry voltage has passed to a trigger voltage, which passage resulted from immersion of the substrate or counter electrode in the electrolytic solution;
- (d) waiting for a defined delay period after the time of the trigger voltage;
- and
- (e) initiating electrochemical processing of the substrate after the delay period.
Dependencies are inferred from the claim text.