Real-Time Plating Current Control for Copper Deposition
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Solution Overview
Problem
In the electrochemical plating of copper for deep submicron integrated circuits, defects such as pits and voids often form due to challenges in controlling the plating current and voltage, particularly for substrates with high aspect features, leading to suboptimal metal film quality and reliability issues.
Innovation Solution
A method and system that determine the electrical properties of a wafer, such as sheet resistance and surface current, to adjust the plating current or voltage in real-time, using a controller with a processor and inline or in situ analyzers, ensuring the plating conditions match an entry peak current level, thereby preventing defects and maintaining constant current density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrochemical plating is used with fixed plating current or voltage, then the process is simple to operate, but defects such as pits and voids form in the deposited metal film
Solution Approach 1:
The system measures the actual plating current in real-time and compares it to a target current value, then automatically adjusts the plating voltage to maintain the desired current. This closed-loop feedback control prevents defects by ensuring consistent plating conditions throughout the process.
Solution Approach 2:
The patent replaces manual control of plating parameters with an automated electronic control system that uses sensors and processors to dynamically adjust plating conditions, eliminating the need for operator intervention and ensuring precise control.
2Productivity
If high plating current is used to increase deposition rate, then productivity improves, but defects such as pits and voids increase in high aspect features
Solution Approach 1:
The system dynamically adjusts plating parameters based on real-time measurements of actual current and waveform characteristics. The control algorithm modifies plating conditions during the process to optimize both deposition rate and film quality, adapting to changing process conditions rather than using fixed parameters.
Solution Approach 2:
The patent changes multiple plating parameters simultaneously, including current waveform, voltage, and timing, to achieve optimal deposition. By coordinating changes in these parameters, the system maintains high productivity while preventing defects in challenging high aspect features.
3Manufacturing precision
If plating voltage is increased to maintain constant current density, then manufacturing precision improves, but energy consumption increases
Solution Approach 1:
The system continuously monitors actual plating current and uses this feedback to adjust voltage only to the extent necessary to maintain target current density. This prevents excessive voltage application and reduces energy consumption while preserving precise current control for high-quality deposition.
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 improves the electroplating process by reducing defects in the metal layer, enhancing the quality and reliability of the deposited copper film, and maintaining consistent current density across multiple wafers, thus improving the yield and reliability of integrated circuit interconnections.
Implementation Method 1
electrochemical plating (ECP) process
Data Source
AI summary
Methods for use in electrochemical plating processes are described herein. An exemplary method includes determining a wafer electrical property associated with a wafer, wherein the wafer electrical property affects the wafer during an electrochemical plating (ECP) process; adjusting a process parameter to be applied to the wafer during the ECP process based on the determined wafer electrical property, wherein the process parameter specifies at least one of a current or a voltage; and applying the adjusted process parameter to the wafer undergoing the ECP process. In some implementations, the process parameter is adjusted, such that a peak entry current of the ECP process substantially matches a plating current of the ECP process induced following the peak entry current.