Plating Apparatus Feedback Circuit for Current Distribution

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Solution Overview

Problem

The Haring cell test experiences disturbances in current distribution and electrode potential differences between cathodes due to wiring resistance and clip contact resistance, affecting accurate measurement of second current distribution during electroplating.

Innovation Solution

A plating apparatus with a feedback circuit that maintains equal electrode potentials between the pair of cathodes while keeping the summation of electric currents constant, using a plating power source, current measuring circuit, and voltage measuring circuit to correct for potential differences and resistive disturbances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional plating system with wiring and clips is used, then the plating apparatus can be assembled and operated, but wiring resistance and clip contact resistance cause disturbance in current distribution and electrode potential differences

Engineering Contradiction:

Improvecurrent distribution accuracyVSAvoidwiring resistance and clip contact resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and eliminates the harmful wiring resistance and clip contact resistance from the measurement circuit by using a four-terminal measurement method. The current terminals and voltage terminals are separated, allowing voltage measurement without current flow through the wiring resistance, thus removing the harmful effect of wiring resistance and contact resistance on measurement accuracy.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces low-impedance current distribution adjustment means as an intermediary component between the power source and the cathodes. This intermediary actively compensates for voltage drops caused by wiring resistance and contact resistance, maintaining accurate current distribution despite the presence of these harmful factors.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If current is supplied through wiring with resistance, then the plating process can proceed, but potential differences between cathodes occur due to wiring resistance and contact resistance

Engineering Contradiction:

Improveplating process executionVSAvoidelectrode potential measurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the electrical connection into separate current supply paths and voltage measurement paths. By dividing the circuit into current terminals (for power supply) and voltage terminals (for measurement), the system can maintain productive current flow while independently measuring electrode potentials without the interference of wiring resistance and contact resistance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs feedback control through current distribution adjustment means that continuously monitors electrode potentials and actively compensates for potential differences caused by wiring resistance and contact resistance. This feedback mechanism ensures accurate measurement and maintains equal potential conditions despite the presence of resistive elements in the current supply path.

Inventive Principle:

Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution prevents disturbances in current distribution and electrode potential differences, ensuring accurate and uniform electroplating by maintaining constant electric currents and potentials, thereby improving the reliability of the Haring cell test results.

Implementation Method 1

a feedback circuit to have an electrode potential of a first cathode of the pair of cathodes equal to an electrode potential of a second cathode of the pair of cathodes while a summation of electric currents flowing through the pair of cathodes is kept constant

Methodology Applied

Scientific EffectFeedback control: Feedback

Implementation Method 2

wiring resistance, a contact resistance of a clip... disturbance in the current distribution is caused

Methodology Applied

Scientific EffectElectrical resistance: Electrical Resistance

Implementation Method 3

plating is performed with an anode disposed between a pair of cathodes... macrothrowing power (uniform electroplating ability) of plating by which a material is plated on the pair of cathodes

Methodology Applied

Scientific EffectElectroplating: Electroplating

Implementation Method 4

plating power source for supplying an electric current between the anode and the pair of cathodes

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS10988855B2Plating device

Publication Date: 2021.04.27 YAMAMOTO MS

AI summary

A plating apparatus capable of preventing difference in an electrode potential between the pair of cathodes and a disturbance in a current distribution in Haring cell test and so on is provided. A plating apparatus (1) has an anode (12) and a pair of cathodes (13X) (13Y) which are provided in a plating bathtub (11); a plating power source (14) to supply an electric current between the anode (12) and the pair of cathodes (13X) (13Y); and a feedback circuit (21) to have an electrode potential of a first cathode (13X) equal to an electrode potential of a second cathode (13Y) while a summation of electric currents flowing through the pair of cathodes (13X) (13Y) is kept constant.