Intelligent control system for electrochemical plating process

摘要

A method and system are disclosed for controlling plating bath compositions. Speciation analyzers including HPLC and mass spectrometry are employed to separate, detect, identify, and quantify additives and degradation products. A control unit is linked to a plating bath interface, analyzer interface, and valves to control the flow of plating bath to an analyzer sampler and back to plating bath. For each degradation product, a response output is determined for at least one performance factor in terms of an additive equivalent amount that produces the same effect. A data processing unit receives concentration data for additives and degradation products from speciation analyzers and calculates an amount of each additive needed to replenish a used bath. As a result, the bleed-and-feed ratio for maintaining plating baths can be substantially reduced with significant productivity improvement and cost savings in terms of chemicals, chemical disposal, less down time and improved product quality.

主权项

1. An integrated process control method for controlling an electroplating bath that is used to deposit an electroplated film on a substrate, comprising:
(a) an additive's effective nominal (target) concentration that is a nominal concentration of a first additive in the presence of “n” degradation products in addition to a plurality of other additives where n is an integer ≦1 and is determined according to the equation:
effective nominal concentration=nominal concentration +additive equivalent amountwherein (1) the nominal concentration is the target concentration of an additive in a new electroplating bath, or in a working electroplating bath under significant bleed and feed in which the concentration of degradation products are kept low and (2) the additive equivalent amount of an additive is the amount of the additive that would produce the same electroplating effect as the presence of the degradation products in an electroplating bath;
(b) calculating an amount of the first additive and each of the plurality of additives (addition amount) required to replenish the consumed additives at periodic intervals according the equation:
addition amount=effective nominal concentration −measured concentrationwherein the measured concentration is the concentration of the additive in the electroplating bath determined by one or more analytical speciation techniques; and
(c) replenishing the electroplating bath by adding the additive amount of the first additive and each of the plurality of additives.