Systems and methods for monitoring plating and etching baths
First Claim
1. A microfluidic system for monitoring the composition of electrolyte bath fluids, the microfluidic system comprising:
- (a) a sampling probe comprising;
(i) a chip substrate having a measurement microchannel wherein the measurement microchannel has areal dimensions of less than 0.006 sq. mm; and
(ii) a set of electrodes disposed on an inner surface of the measurement microchannel;
(b) monitoring electronics connected to the set of electrodes, wherein the monitoring electronics and set of electrodes are configured to measure one or more electrochemical properties of a predetermined volume of the bath fluids pumped through the measurement microchannel of the microfluidic system; and
an external fluid pumping arrangement connectable to an inlet disposed at an end of the measurement microchannel.
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Abstract
Methods and systems for monitoring electrolyte bath fluids are provided. The electrolyte bath fluids can be electroplating, electroless plating or etching solutions. The monitoring systems employ microfluidic devices, which have built in microfluidic channels and microfabricated thin-film electrodes. The devices are configured with fluid pumps to control the movement and mixing of test fluids through the microfluidic channels. The microfabricated thin-film electrodes are configured so that the plating or etching bath fluid composition can be characterized by electrochemical measurements. The monitoring methods and system provide faster measurement times, generate minimal waste, and occupy dramatically reduced physical space compared to conventional bath-monitor systems. The monitoring systems and method also provide low-cost system and methods for measuring or monitoring electroless plating bath rates.
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Citations
21 Claims
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1. A microfluidic system for monitoring the composition of electrolyte bath fluids, the microfluidic system comprising:
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(a) a sampling probe comprising; (i) a chip substrate having a measurement microchannel wherein the measurement microchannel has areal dimensions of less than 0.006 sq. mm; and (ii) a set of electrodes disposed on an inner surface of the measurement microchannel; (b) monitoring electronics connected to the set of electrodes, wherein the monitoring electronics and set of electrodes are configured to measure one or more electrochemical properties of a predetermined volume of the bath fluids pumped through the measurement microchannel of the microfluidic system; and an external fluid pumping arrangement connectable to an inlet disposed at an end of the measurement microchannel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A microfluidic system for determining additive concentrations in an etching bath solution, the microfluidic system comprising:
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a) a chip substrate having at least one microchannel and a set of thin film electrodes disposed on an interior surface of the microchannel wherein the at least one microchannel has areal dimensions of less than 0.006 sq. mm; b) at least one pump connected to the microchannel for flowing fluids through the microchannel; c) at least one of a potentiostat and a power supply that are electrically connected to the electrodes; and d) means for measuring an electric current when a voltage is applied to said electrodes, wherein the electric current is function of the composition of fluids flowing through the microchannel of the microfluidic system. - View Dependent Claims (13, 14, 15)
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16. A method of monitoring the composition of plating or etching bath fluids, the method comprising:
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(a) providing a microfluidic sampling probe that comprises; a chip substrate having a measurement microchannel; a set of electrodes disposed on an inner surface of the measurement microchannel wherein the measurement microchannel has areal dimensions of less than 0.006 sq. mm; and an external fluid pumping arrangement connectable to an inlet disposed at an end of the measurement microchannel; (b) flowing a test sample of the bath fluids through the measurement channel; and (c) applying and measuring electrical voltages and/or currents at the electrodes to determine one or more electrochemical properties of the test sample of the bath fluids flowing through the measurement microchannel, wherein the determined electrochemical properties correspond to a composition of the bath fluids. - View Dependent Claims (17, 18, 19)
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20. A method of monitoring an etching bath, the method comprising:
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providing a microchannel having areal dimensions of less than 0.006 sq. mm; controlling a flow rate of a test solution of the etching bath through a microfluidic sampling probe comprising a chip substrate having a microchannel having a working electrode comprising an etchable material and a reference electrode disposed in the microchannel; applying a voltage between the working and reference electrodes; measuring and recording the current flowing between the working and counter electrodes; and measuring the dissolution of the etchable material from the working electrode. - View Dependent Claims (21)
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Specification