Dynamic Current Control for High Sheet Resistance Electroplating
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Solution Overview
Problem
Electroplating systems face challenges in maintaining uniformity and desired current density on substrates with thin seed layers, leading to non-uniform, voided, or defective metal layers due to changing sheet resistance and terminal effects, which reduce manufacturing yield.
Innovation Solution
Implementing accelerated dynamic current control with 50 to 1000 current changes within a 10-20 second interval, combined with optimization techniques, to dynamically adjust electrode currents based on measured sheet resistance changes, ensuring consistent current distribution across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional electroplating systems are used with thin seed layers (50 Ohm/sq or higher), then the seed layer can be applied faster and with fewer materials, but the current density becomes non-uniform and the plated layer contains voids and defects
Solution Approach 1:
The patent implements dynamic current control where the electroplating system continuously adjusts current density parameters during the plating process. The system monitors sheet resistance changes in real-time and modifies electrode current distribution dynamically to compensate for resistance variations, maintaining uniform current density across the substrate surface throughout the electroplating cycle.
Solution Approach 2:
The system incorporates feedback mechanisms that measure sheet resistance during electroplating and use this information to adjust current density parameters. The measured sheet resistance values are fed back to the control system, which then modifies the current distribution to compensate for changes in seed layer conductivity, ensuring uniform plated layer formation.
2Manufacturing precision
If dynamic current control is implemented to adjust for sheet resistance changes, then current density uniformity improves, but the system complexity increases
Solution Approach 1:
The electroplating system performs self-diagnosis and self-correction by automatically measuring its own sheet resistance during the plating process and adjusting its current distribution accordingly. The system uses built-in sensors and control algorithms to monitor and compensate for its own performance variations, reducing the need for external intervention and simplifying the overall control architecture.
3Productivity
If the current density is increased to compensate for high seed layer resistance, then plating speed improves, but terminal effects cause higher current density at edges and junctions leading to voids and defects
Solution Approach 1:
The patent applies local quality control by adjusting current density parameters specifically at problem areas such as edges and junctions where terminal effects occur. The system identifies locations prone to excessive current density and applies localized compensation, reducing current at these specific points while maintaining appropriate current levels in other areas, thereby preventing voids and defects without sacrificing overall plating speed.
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 significantly improves electroplating results on highly resistive seed layers by maintaining uniformity and desired characteristics of the plated metal layers, enhancing manufacturing yield and reducing defects.
Implementation Method 1
A challenge in electroplating uniform metal layers in manufacturing semiconductor and other micro-scale devices
Implementation Method 2
electrochemical plating systems
Implementation Method 3
The distribution of electrical current in the plating solution is a function of the uniformity of the seed layer
Implementation Method 4
the resistance of the seed layer, the configuration/condition of the anode
Data Source
AI summary
In an electroplating process, electric current is applied to two or more electrodes, with the current varying over time according to a multi-variable function. The multi-variable current function is integrated over time, for each electrode, to determine a net plating charge delivered. A plating profile of a plated-on layer of material is compared to a target plating profile. Deviations between the actual plating profile and the target plating profile are identified and used to determine new net plating charges for each electrode. One or more variables of the multi-variable function is changed to provide a new multi-variable function. The new net plating charges are distributed according to the new multi-variable current function, and are used to electroplate a layer of material on a second substrate.