Electroplating Oxide Detection via Electrochemical Response
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Solution Overview
Problem
The challenge in semiconductor processing is the difficulty in electroplating metal due to the shrinking feature sizes and thinning metal seed layers, which are often hindered by the presence of oxide on the substrate surface, leading to issues like void formation in recessed features.
Innovation Solution
A method is developed to determine and manage the amount of oxide on a substrate surface by monitoring current and voltage responses during immersion in an electrolyte, using a calibration procedure to set thresholds for acceptable oxide levels, and selecting pre-treatment conditions to remove oxide, thereby ensuring accurate oxide detection and removal without the need for separate metrology tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate metrology tools are used to measure oxide on substrate surfaces, then measurement precision is improved, but device complexity and processing time increase
Solution Approach 1:
The patent combines the oxide detection function with the electroplating process by measuring current and voltage responses during substrate immersion in electrolyte. This integration eliminates the need for separate metrology tools, reducing device complexity while maintaining oxide detection capability through electrochemical response analysis
Solution Approach 2:
The electroplating system is given multiple functions: it both deposits metal and detects oxide presence on the substrate surface. By utilizing the electrolyte immersion step for dual purposes (plating preparation and oxide measurement), the system achieves multi-functionality without requiring additional specialized equipment
2Measurement precision
If separate metrology tools and queue times are used for oxide detection, then measurement precision is improved, but productivity decreases
Solution Approach 1:
The oxide detection is performed continuously during the substrate immersion step in the electroplating process, rather than as a separate discrete operation. This continuity eliminates queue times between detection and plating, maintaining processing flow and improving productivity while achieving accurate oxide measurement
Solution Approach 2:
The oxide detection is performed as a preliminary step integrated into the immersion process before metal deposition begins. By detecting and accounting for oxide presence during the preparation phase, the system ensures accurate plating results without requiring post-processing measurements or rework
3Manufacturing precision
If pre-treatment conditions are optimized to remove oxide, then manufacturing precision is improved, but process complexity increases
Solution Approach 1:
The system uses feedback from the current and voltage response measurements to determine oxide presence and adjust pre-treatment conditions accordingly. This closed-loop control enables optimized oxide removal without requiring complex manual intervention, achieving high deposition quality through automated process adjustment
Solution Approach 2:
The patent adjusts pre-treatment parameters such as immersion time, current density, and voltage based on the detected oxide levels. By dynamically changing these process parameters according to measured conditions, the system achieves precise oxide removal and high-quality metal deposition without fixed complex procedures
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 allows for accurate and efficient oxide detection and removal directly within the electroplating process, reducing queue times and ensuring high-quality metal deposition by eliminating the risk of oxide formation during processing, thus improving productivity and accuracy.
Implementation Method 1
immersing the substrate in electrolyte, where during and/or immediately after immersing the substrate, either: (i) a current applied to the substrate is controlled, or (ii) a voltage applied between the substrate and a reference is controlled; (c) measuring either a voltage response or a current response
Data Source
AI summary
Methods and apparatus for determining whether a substrate includes an unacceptably high amount of oxide on its surface are described. The substrate is typically a substrate that is to be electroplated. The determination may be made directly in an electroplating apparatus, during an initial portion of an electroplating process. The determination may involve immersing the substrate in electrolyte with a particular applied voltage or applied current provided during or soon after immersion, and recording a current response or voltage response over this same timeframe. The applied current or applied voltage may be zero or non-zero. By comparing the current response or voltage response to a threshold current, threshold voltage, or threshold time, it can be determined whether the substrate included an unacceptably high amount of oxide on its surface. The threshold current, threshold voltage, and/or threshold time may be selected based on a calibration procedure.