Substrate Holder Protective Electrode for Plating Corrosion
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Solution Overview
Problem
In electroplating, plating solutions can leak into substrate holders due to substrate irregularities or seal deterioration, causing corrosion and poor electrical continuity, and existing techniques fail to effectively prevent this or detect leaks promptly.
Innovation Solution
A substrate holder with a protective electrode biased to a higher potential than the seed layer, along with a holder main body that seals the internal space and stores a liquid to cover the electrode and contact areas, preventing corrosion and detecting leaks through electrical conductivity monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the substrate holder uses a sealed internal space to prevent plating solution entry, then the seed layer is protected from corrosion, but plating solution may still enter due to substrate irregularities or seal deterioration
Solution Approach 1:
The patent applies preliminary anti-action by introducing a protective electrode that creates a counteracting electrochemical environment before plating solution leakage can cause damage. The protective electrode is positioned to preemptively neutralize corrosive effects through electrochemical reactions, preventing seed layer corrosion even when plating solution enters the sealed space.
Solution Approach 2:
The patent converts the harmful presence of plating solution in the sealed space into a beneficial effect by using the protective electrode to create a controlled electrochemical environment. The plating solution that would otherwise cause corrosion is instead utilized as an electrolyte for the protective electrode's electrochemical reactions, transforming the harmful factor into a functional medium.
2Reliability
If a protective electrode is introduced to prevent corrosion, then seed layer integrity is maintained, but device complexity increases
Solution Approach 1:
The protective electrode serves multiple functions: it prevents seed layer corrosion through electrochemical protection, detects plating solution leakage via conductivity changes, and can be integrated with existing substrate holder components. This multi-functionality reduces the need for separate protection and detection systems, thereby limiting the increase in device complexity.
Solution Approach 2:
The protective electrode system is designed to be self-regulating through electrochemical reactions that automatically respond to the presence of plating solution. The system uses the plating solution itself as the electrolyte, eliminating the need for separate protective coatings or complex control mechanisms, thereby maintaining simplicity while providing effective corrosion protection.
3Reliability
If the internal space is filled with liquid to cover contact areas, then electrical continuity is maintained, but detection of plating solution invasion becomes difficult
Solution Approach 1:
The patent implements feedback by using the protective electrode to continuously monitor electrical conductivity changes in the liquid within the sealed space. When plating solution invades the space, it alters the conductivity, which is detected by the electrode and can trigger alarm or shutdown signals, providing real-time feedback on seal integrity without disrupting electrical continuity.
Solution Approach 2:
The patent replaces mechanical detection methods with electrical conductivity measurement. Instead of using mechanical sensors or visual inspection to detect plating solution invasion, the system uses electrical conductivity changes measured by the protective electrode, which is more sensitive and can operate continuously without interfering with the sealed space's liquid coverage.
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 effectively suppresses seed layer corrosion and maintains plating film uniformity even when the plating solution enters the sealed space, while promptly detecting leaks and preventing corrosion.
Implementation Method 1
a protective electrode that is biased to a higher potential side relative to the contact or that comprises a material having a lower spontaneous potential than a spontaneous potential of the seed layer
Implementation Method 2
configured to store therein a liquid that covers at least part of the protective electrode and at least a contact location between the seed layer and the contact
Implementation Method 3
an internal space, the internal space being configured to place therein an outer circumferential portion of the substrate, the contact and the protective electrode such as to be sealed from outside of the substrate holder
Data Source
AI summary
There is provided a substrate holder configured to hold a substrate such that the substrate is exposed to and is brought into contact with a plating solution to be plated. The substrate holder comprises a contact that comes into contact with a seed layer formed on a surface of the substrate to feed electricity; a protective electrode that is biased to a higher potential side relative to the contact or that comprises a material having a lower spontaneous potential than a spontaneous potential of the seed layer and that is electrically connected with the seed layer directly or via an electrical conductor; and a holder main body provided with an internal space being configured to place therein an outer circumferential portion of the substrate, the contact and the protective electrode such as to be sealed from outside of the substrate holder in a state that the substrate is held by the substrate holder and configured to store therein a liquid that covers at least part of the protective electrode and at least a contact location between the seed layer and the contact.