Elongated Anode Segmentation for Plating Uniformity
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Solution Overview
Problem
The terminal effect in electroplating, where current concentrates at the peripheral edge of a substrate due to a thin seed layer, leads to non-uniform film thickness and reduced plating rates, necessitating increased distances between the anode and substrate to mitigate this issue, resulting in larger plating tanks and higher costs.
Innovation Solution
A plating apparatus with a substrate holder and multiple elongate anodes arranged parallel to the substrate, where the longitudinal direction of each anode faces the electric contact, allowing for a smaller distance between the anode and substrate, thereby reducing the terminal effect without the need for a regulating plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the distance between the anode and substrate is increased to reduce the terminal effect, then the uniformity of film thickness is improved, but the volume of the plating tank and the size of the plating apparatus increase
Solution Approach 1:
The anode is divided into multiple segments (first anode, second anode, third anode) arranged at different positions and orientations. This segmentation allows each anode segment to independently influence specific regions of the substrate, enabling uniform current distribution without increasing the overall tank volume.
Solution Approach 2:
Different anode segments are positioned to address local current distribution issues at different locations on the substrate. The first anode addresses the center region, while the second and third anodes address peripheral regions, creating locally optimized current distribution that eliminates the terminal effect without requiring a large distance between anode and substrate.
2Manufacturing precision
If the distance between the anode and substrate is increased to reduce the terminal effect, then the uniformity of film thickness is improved, but the amount of plating solution required increases
Solution Approach 1:
The segmented anode configuration enables effective terminal effect reduction with a compact anode-substrate distance, thereby minimizing the plating tank volume and the quantity of plating solution required while still achieving uniform film thickness distribution.
3Manufacturing precision
If a regulating plate is installed between the anode and substrate to adjust electric potential distribution, then the uniformity of film thickness is improved, but the device complexity increases
Solution Approach 1:
The function of the regulating plate is extracted and replaced by the segmented anode configuration. Instead of adding a regulating plate to modify the electric field, the patent uses strategically positioned anode segments to directly create the desired current distribution, eliminating the need for additional regulating components.
Solution Approach 2:
The invention changes the geometric parameters and spatial arrangement of the anode itself (dividing it into multiple segments at different positions and orientations) to achieve uniform current distribution, rather than changing the electric potential distribution through an additional regulating plate.
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 minimizes the terminal effect, allowing for a smaller plating tank and reduced plating solution volume, while maintaining uniform film thickness and reducing operational costs.
Implementation Method 1
the electroplating method that allows miniaturization and provides comparatively stable performance has been often used
Implementation Method 2
a current corresponding to a combined resistance of an electric resistance value of a plating solution and an electric resistance value of the seed layer from a center portion of the substrate to the electric contact flows through the center portion of the substrate
Data Source
AI summary
A plating apparatus that reduces a terminal effect is provided. The plating apparatus is provided. The plating apparatus includes a substrate holder for holding a substrate as a plating object, an electric contact disposed on the substrate holder to apply a current to a substrate, and a plurality of anodes arranged to face the substrate holder. Each of the plurality of anodes has a long and thin shape. Each of the plurality of anodes is arranged such that a longitudinal direction of the anode is parallel to a surface of a substrate held onto the substrate holder and such that at least one end in the longitudinal direction of each of the anodes faces the electric contact of the substrate holder.