Segmented Reference Electrode for Uniform Current Density
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Solution Overview
Problem
Existing electroplating processes face challenges in achieving uniform current density distribution across the substrate during immersion, particularly due to variations in potential and conductivity, which can lead to non-uniform deposition and potential damage to the seed layer.
Innovation Solution
The use of a dynamically shaped and positioned reference electrode, such as a ring or arc-shaped electrode with adjustable segments, allows for precise control of the potential difference and conductivity, ensuring a consistent current density across the substrate by measuring and controlling the potential over a wider area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional reference electrode is used during substrate immersion, then the electroplating process can be carried out, but the current density distribution becomes non-uniform due to variations in potential and conductivity
Solution Approach 1:
The reference electrode is divided into multiple independently controllable segments arranged in an arc or ring shape. Each segment can be individually activated or deactivated based on the immersion depth and position of the substrate, allowing precise control of the reference potential at different locations to achieve uniform current density distribution across the substrate surface.
Solution Approach 2:
The reference electrode configuration is made dynamically adjustable during the immersion process. The controller selectively activates different segments based on real-time immersion conditions, transforming the static reference electrode into a dynamic system that adapts to changing substrate positions and immersion depths, thereby maintaining uniform current density throughout the process.
2Manufacturing precision
If the reference electrode is positioned to monitor potential at a single point, then the measurement is simple, but the current density control is insufficient due to potential variations across the substrate area
Solution Approach 1:
The reference electrode is divided into multiple independently controllable segments arranged in an arc or ring shape. Each segment can be individually activated or deactivated based on the immersion depth and position of the substrate, allowing precise control of the reference potential at different locations to achieve uniform current density distribution across the substrate surface.
Solution Approach 2:
The reference electrode transitions from a single-point measurement to a distributed multi-segment structure arranged in an arc or ring configuration. This spatial distribution across multiple dimensions allows the system to capture potential variations across different areas of the substrate, providing comprehensive control over current density uniformity.
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 approach results in a more uniform and controlled current density distribution during electroplating, reducing the risk of seed layer degradation and improving the quality of the deposited metal layer.
Implementation Method 1
monitoring a potential difference between the substrate and a reference electrode
Implementation Method 2
electroplating metal onto the substrate
Implementation Method 3
electroplating is used to deposit a thicker layer of copper over the seed layer
Data Source
AI summary
Various embodiments herein relate to methods and apparatus for electroplating metal onto substrates. In various cases, a reference electrode may be modified to promote improved electroplating results. The modifications may relate to one or more of the reference electrode's shape, position, relative conductivity compared to the electrolyte, or other design feature. In some particular examples the reference electrode may be dynamically changeable, for example having a changeable shape and/or position. In a particular example the reference electrode may be made of multiple segments. The techniques described herein may be combined as desired for individual applications.