Segmented Anode Copper Plating for Void-Free Narrow Gap Filling
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Solution Overview
Problem
The challenge of filling narrower gaps in copper interconnection structures for semiconductor devices using electroplating is exacerbated by high resistivity and the formation of voids due to direct current plating, particularly with thinner Cu seed layers or new seed layer materials, leading to issues like increased resistance, signal delay, and reliability concerns.
Innovation Solution
A plating method and apparatus that utilizes a divided anode chamber with independent anode zones and controlled power supply switching, combined with a segmented cathode chamber and precise plating solution distribution, to achieve uniform metal layer deposition by periodically adjusting power values and periods on multiple anodes, ensuring effective filling of recessed areas without voids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct current electroplating is used to fill recessed areas, then plating rate increases, but voids form in narrow gaps
Solution Approach 1:
The patent applies pulsed direct current electroplating instead of continuous direct current. The power supply operates in periodic cycles with on-time (ton) and off-time (toff), allowing metal ions to diffuse during the off-period and preventing void formation while maintaining acceptable plating rates. The pulse frequency and duty cycle are optimized to balance deposition rate and filling quality.
Solution Approach 2:
The patent dynamically adjusts plating parameters during the process. Multiple anodes are switched on and off in different sequences and time periods, creating dynamic current distribution patterns that adapt to the evolving plating state. This dynamic control allows optimization of both plating rate and void prevention throughout the filling process.
2Length of moving object
If thinner Cu seed layer or new seed layer materials are used for narrower lines, then device scaling is enabled, but resistivity increases making electroplating difficult
Solution Approach 1:
Pulsed electroplating with optimized duty cycle compensates for the high resistivity of thin seed layers. The periodic current application allows better ion transport and reduces heating effects that would be problematic with thin, high-resistivity seed layers, enabling successful plating on scaled-down interconnects.
Solution Approach 2:
The patent changes multiple parameters including pulse frequency, duty cycle, and current density to optimize plating on thin seed layers. By adjusting these parameters, the process accommodates the electrical and physical characteristics of thinner, higher-resistivity seed layers while maintaining plating quality.
3Manufacturing precision
If multiple anodes with independent power supplies are used, then uniform plating profile is achieved, but device complexity increases
Solution Approach 1:
The anode system is segmented into multiple independently controlled anodes, each with its own power supply. This segmentation allows different regions of the substrate to receive optimized current distribution, achieving uniform plating profiles across the entire substrate area despite variations in distance and geometry.
Solution Approach 2:
Each anode serves multiple functions: it provides current for plating, acts as a current distribution element, and can be independently controlled to address specific plating challenges in different regions. This multi-functionality reduces the need for additional specialized components.
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 enhances the ability to fill narrower gaps in semiconductor devices with copper, reducing void formation and improving the reliability and efficiency of interconnection structures by minimizing resistivity and ensuring uniform plating profiles.
Implementation Method 1
A plating method and apparatus that utilizes a divided anode chamber with independent anode zones and controlled power supply switching
Implementation Method 2
immersing a substrate into plating solution of a plating chamber assembly including at least a first anode and a second anode
Data Source
AI summary
The present invention discloses a plating apparatus and plating methods for plating metal layers on a substrate. In an embodiment, a plating method comprises: step 1: immersing a substrate into plating solution of a plating chamber assembly including at least a first anode and a second anode; step 2: turning on a first plating power supply applied on the first anode, setting the first plating power supply to output a power value P11 and continue with a period T11; step 3: when the period Tn ends, adjusting the first plating power supply applied on the first anode to output a power value P12 and continue with a period T12, at the same time, turning on a second plating power supply applied on the second anode, and setting the second plating power supply to output a power value P21 and continue with a period T21; and step 4: when the period T21 ends, adjusting the second plating power supply applied on the second anode to output a power value P22 and continue with a period T22, wherein step 2 to step 4 are performed periodically.