Polygonal Substrate Plating Current Distribution Control
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Solution Overview
Problem
The electrolytic plating method for polygonal substrates results in uneven current density distribution and film thickness due to the ununiform terminal effect, leading to lower in-plane uniformity of the plated film compared to circular substrates.
Innovation Solution
A plating apparatus with a substrate holder that includes power feeding members along the sides of the polygonal substrate, allowing for the simultaneous supply of currents of different values to side central, intermediate, and corner regions, controlled by a device to manage current distribution and alleviate the terminal effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electrolytic plating is applied to polygonal substrates using conventional uniform current supply, then the plating process can be completed, but the film thickness becomes uneven due to ununiform terminal effect
Solution Approach 1:
The substrate perimeter is divided into multiple regions (corner regions, side central regions, intermediate regions), and separate power feeding members are provided for each region to enable independent current control, thereby resolving the uniformity issue caused by the terminal effect
Solution Approach 2:
Different current values are supplied to different regions of the substrate based on their specific terminal effect characteristics, with higher currents to corner regions and lower currents to side central regions, achieving uniform film thickness through localized current optimization
2Manufacturing precision
If conventional substrate holders are used for polygonal substrates, then the substrate can be held, but the terminal effect causes ununiform current density distribution
Solution Approach 1:
The substrate holder is configured with multiple separate power feeding members positioned at different locations (corners, side centers, intermediates), transforming a simple holding structure into a segmented current distribution system that addresses the terminal effect
Solution Approach 2:
The substrate holder acts as an intermediary device that not only holds the substrate but also actively manages current distribution through its integrated power feeding members, mediating between the power supply and the substrate to achieve uniform plating
3Manufacturing precision
If current is supplied uniformly to all regions of the substrate, then the power supply is simple, but the film thickness in corner regions becomes excessively thick
Solution Approach 1:
The power supply system is designed to provide different current values to different substrate regions, with corner regions receiving higher currents and side central regions receiving lower currents, achieving uniform film thickness through localized current optimization
Solution Approach 2:
The power supply is segmented into multiple independent output channels, each connected to specific power feeding members at different substrate regions, enabling independent current control for each region to prevent excessive thickness in corner areas
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
Enhances the in-plane uniformity of the film thickness on polygonal substrates by optimizing current distribution, reducing the disparities in film thickness caused by the terminal effect.
Implementation Method 1
a current which corresponds to a combined resistance of an electric resistance value of a plating solution and an electric resistance value of a seed layer from the central portion of the substrate to the electric contracts flows
Implementation Method 2
When wiring or a bump is formed by an electrolytic plating method, a seed layer (a power feeding layer) with low electric resistance is formed on the surface of a barrier metal
Data Source
AI summary
In-plane uniformity of a film that is plated on a polygonal substrate is enhanced. An anode holder configured to hold an anode, a substrate holder configured to hold a polygonal substrate, a plating bath for accommodating the anode holder and the substrate holder, and dipping the anode and the substrate in a plating solution, and a control device for controlling a current that flows between the anode and the substrate are included. The substrate holder has a plurality of power feeding members that are disposed along respective sides of the polygonal substrate. The control device is configured to be able to control the current so that currents of at least two different values are simultaneously supplied to the plurality of power feeding members.