Electroplating Cell with Movable Substrate and Edge Electrodes
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Solution Overview
Problem
Electrochemical plating of high aspect ratio features faces challenges such as the 'terminal effect,' which causes non-uniform plating rates and incomplete filling due to high substrate resistivity, especially at the perimeter of substrates, requiring dynamic adjustment of plating profiles to optimize film properties and prevent voids.
Innovation Solution
An electrochemical plating cell with an encased auxiliary electrode assembly and a diffusion plate with a restricted area, allowing for adjustable plating profiles by varying the electric field and substrate position, and using a substrate support member to move the substrate through different elevations relative to a restrictor, ensuring uniform current distribution and controlled plating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the seed layer thickness is reduced to less than 500 Å (or below 100 Å) to accommodate high aspect ratio features, then the aspect ratio requirement is met, but the substrate resistivity increases causing terminal effect and non-uniform plating rate
Solution Approach 1:
The patent applies local quality by creating non-uniform current distribution across the substrate surface using edge electrodes and guard rings. These electrodes are positioned at specific locations (edges and perimeters) to locally modify the electric field and current density, compensating for the terminal effect at substrate edges while maintaining appropriate plating rates in the center region.
Solution Approach 2:
The patent employs dynamic control of plating parameters including multi-stage plating processes with varying current densities, pulse plating techniques, and real-time adjustment of electrode potentials. This dynamic approach allows the system to adapt to changing substrate conditions during plating, maintaining uniformity despite the reduced seed layer thickness.
2Adaptability or versatility
If conventional plating cells with resistive elements, multi-segment anodes, or passive shields are used to modulate plating profile, then some profile control is achieved, but the ability to dynamically adjust between different plating profiles (uniform or edge-thin) is limited
Solution Approach 1:
The patent segments the electrode system into multiple independent controllable elements including edge electrodes, guard rings, and multi-segment anodes. Each segment can be independently biased or activated, allowing flexible configuration to achieve different plating profiles (uniform, edge-thin, or edge-thick) without requiring complete redesign of the plating cell.
Solution Approach 2:
The patent designs the plating cell with multi-functional electrodes that can serve different purposes depending on bias configuration. The same edge electrodes and guard rings can be used to achieve both uniform plating profiles and edge-thin profiles by adjusting the applied potentials, making the system universally applicable to different plating requirements.
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 solution minimizes the terminal effect, achieves uniform plating profiles, and optimizes film properties by dynamically adjusting the plating rate across the substrate, reducing voids and enhancing the overall plating process efficiency.
Implementation Method 1
Metallization of these features is generally accomplished via an electrochemical plating process
Implementation Method 2
a metal, such as copper, is plated onto a substrate
Implementation Method 3
an electrochemical processing cell configured to have an electric field with different profiles at different locations
Implementation Method 4
a substrate support member configured to move the substrate within the fluid basin among different elevations relative to the restrictor
Data Source
AI summary
A method and apparatus for plating a metal onto a substrate. One embodiment of the present invention provides an apparatus for electroplating a substrate. The apparatus comprises a fluid basin, an anode disposed near a bottom of the fluid basin, a restrictor disposed above the anode, and a substrate support member configured to move the substrate within the fluid basin among different elevations relative to the restrictor. Plating profiles on the substrate may be adjusted by changing the elevation of the substrate during plating.