Dynamic Substrate Motion for Uniform Metallization
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Solution Overview
Problem
Conventional metallization methods in electrolyte solutions face challenges in achieving uniform metallic film deposition, particularly in deep cavities like TSVs, due to non-uniform acoustic wave distribution and high energy loss, leading to inefficient deposition rates and potential impurity formation.
Innovation Solution
The use of an ultra/mega sonic device with a dynamically controlled substrate motion and a coupling reflection plate to form a standing wave, ensuring uniform sonic energy distribution across the substrate surface, thereby enhancing film uniformity and deposition rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional metallization methods are used in electrolyte solutions, then deposition can occur, but the acoustic wave distribution is non-uniform and energy loss is high, leading to low deposition rates and poor film uniformity
Solution Approach 1:
The patent applies dynamic motion control to the substrate, making it oscillate in the acoustic field to continuously pass through regions of different acoustic intensity. This dynamic approach ensures uniform cumulative acoustic energy exposure across the substrate surface, resolving the non-uniform deposition problem while maintaining high deposition rates
Solution Approach 2:
The substrate undergoes periodic oscillation motion through the acoustic field, repeatedly passing through high and low intensity regions. This periodic action accumulates uniform acoustic energy exposure over time, achieving both high deposition rate and uniform film quality
2Loss of energy
If standing wave is formed in the plating bath, then acoustic energy is maintained within the bath, but the power intensity distribution between node and anti-node is non-uniform, leading to non-uniform deposition
Solution Approach 1:
By dynamically oscillating the substrate through the standing wave field, the patent ensures that each point on the substrate surface periodically passes through both node and anti-node regions. This dynamic motion compensates for the inherent non-uniformity of standing waves, achieving uniform cumulative acoustic energy exposure and uniform deposition
Solution Approach 2:
The substrate oscillation is designed to pre-determine the path through the acoustic field, ensuring that each location receives equal cumulative acoustic energy exposure before deposition completes. This preliminary motion control guarantees uniformity despite the non-uniform standing wave distribution
3Manufacturing precision
If organic additives are added to control local deposition rate in deep cavities, then gapfill can be achieved, but byproduct formation occurs that acts as nuclei for void formation, reducing device reliability
Solution Approach 1:
The patent uses mechanical vibration (acoustic wave) to enhance mass transport and chemical exchange in and around deep cavities. This physical mechanism replaces or reduces reliance on organic additives, preventing byproduct formation while achieving uniform gapfill through vibration-enhanced diffusion and convection
Solution Approach 2:
The patent replaces chemical mechanisms (organic additives) with physical mechanisms (acoustic wave vibration) to control deposition. This substitution eliminates the formation of harmful byproducts while maintaining effective control over local deposition rates in deep cavities
4Adaptability or versatility
If high aspect ratio cavities like TSV are metallized, then vertical connections are achieved, but diffusion path length is long, limiting chemical exchange and deposition rate
Solution Approach 1:
The acoustic wave vibration mechanically enhances mass transport within deep high aspect ratio cavities, dramatically reducing the effective diffusion path length. This vibration-induced convection and enhanced diffusion enable rapid chemical exchange, achieving high deposition rates even in extremely deep cavities
Solution Approach 2:
The periodic acoustic vibration creates repeated cycles of enhanced mass transport into and out of deep cavities. This periodic action continuously refreshes the chemical environment within cavities, maintaining high deposition rates throughout the entire cavity depth
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 achieves highly uniform metallic film deposition at a significantly higher rate than conventional methods, minimizing energy loss and impurity formation, and stabilizing the acoustic field for consistent performance.
Implementation Method 1
applying at least one ultra/mega sonic device to a metallization apparatus
Implementation Method 2
the maximum deposition rate by electrochemical methods in a mass-transfer limited case is related to the limiting current density, which is inversely proportional to diffusion double layer thickness
Implementation Method 3
A standing wave formed in two parallel planes maintains the energy within the bath to minimize the energy lost
Implementation Method 4
the substrate is dynamically controlled so that the position of the substrate passing through the entire acoustic field with different power intensity in each motion cycle
Implementation Method 5
metallization of substrate from electrolyte solutions
Data Source
AI summary
The present invention relates to applying at least one ultra/mega sonic device and its reflection plate for forming standing wave in a metallization apparatus to achieve highly uniform metallic film deposition at a rate far greater than conventional film growth rate in electrolyte. In the present invention, the substrate is dynamically controlled so that the position of the substrate passing through the entire acoustic field with different power intensity in each motion cycle. This method guarantees each location of the substrate to receive the same amount of total sonic energy dose over the interval of the process time, and to accumulatively grow a uniform deposition thickness at a rapid rate.