Auxiliary Electrodes Balance Electric Field for Uniform Plating
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Solution Overview
Problem
The existing plating processes face challenges in achieving uniform plated film thickness due to electric field sneaking between the substrate holder and the plating tank, which is difficult to prevent without relying on physical/mechanical structures.
Innovation Solution
A plating apparatus is designed with a substrate holder and a plating tank configuration that includes a first and second tank communicating via a gap, along with auxiliary anode and cathode electrodes and power sources to manage the electric current flow, preventing electric field sneaking by balancing current distribution between the surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a substrate holder with openings on both front and back sides is used to plate both surfaces of the substrate, then productivity is improved by simultaneous dual-side plating, but manufacturing precision deteriorates due to electric field sneaking causing non-uniform plated film thickness
Solution Approach 1:
An auxiliary electrode is introduced as an intermediary element positioned between the substrate holder and plating tank. This auxiliary electrode mediates the electric field distribution by providing an additional current path that prevents electric field sneaking, thereby maintaining uniform plated film thickness while enabling dual-side plating operations
Solution Approach 2:
The invention changes the electrical parameters of the plating system by introducing an auxiliary electrode with controllable potential. By adjusting the potential of the auxiliary electrode, the electric field distribution in the plating tank is optimized to prevent field sneaking through the substrate holder, ensuring uniform current density and consistent film thickness on both substrate surfaces
2Ease of operation
If a large gap exists between the substrate holder and plating tank, then ease of operation is improved by facilitating substrate holder insertion and removal, but manufacturing precision deteriorates due to increased electric field sneaking
Solution Approach 1:
The auxiliary electrode serves as a mediator that compensates for the large gap between the substrate holder and plating tank. By positioning the auxiliary electrode appropriately, it creates a controlled electric field environment that prevents field sneaking even when the substrate holder is positioned far from the plating tank wall, thus maintaining manufacturing precision while preserving operational ease
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 configuration ensures uniform plating thickness by effectively reducing or preventing electric field sneaking, thereby enhancing the consistency of the plated film on substrates.
Implementation Method 1
a part of an electric field, that has an electric field direction from an anode to a substrate, may sneak up on a back surface of the substrate held by a substrate holder
Implementation Method 2
a voltage is applied between the substrate and the anode, so that an electroplated film can be formed on the exposed surface of the substrate
Data Source
AI summary
Provided are a plating apparatus and a plating method for preventing or mitigating electric field diversion irrespective of the physical or mechanical structure. According to one embodiment, provided is a plating apparatus comprising: a substrate holder configured so as to hold a substrate; a plating bath configured so as to accommodate the substrate holder which holds the substrate, and provided with a first tank on a first surface side of the substrate and a second tank on a second surface side of the substrate, the first tank and the second tank communicating with each other with a gap therebetween; a first anode electrode arranged in the first tank of the plating bath; a first power source configured so as to supply a plating current between the substrate and the first anode electrode; an auxiliary anode electrode arranged on the first tank side of the gap; an auxiliary cathode electrode arranged on the second tank side of the gap; and an auxiliary power source configured so as to supply an auxiliary current between the auxiliary anode electrode and the auxiliary cathode electrode.