Copper Plating via-Hole Filling Voltage Feedback Control
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Solution Overview
Problem
The existing copper plating process for semiconductor devices faces challenges in accurately controlling the concentration of additives, leading to void formation and inconsistent film characteristics due to by-products affecting concentration analysis and improper timing of increasing current density during plating.
Innovation Solution
A plating method and apparatus that measures voltage changes over time to adjust additive concentrations and control current density, ensuring the voltage remains within a predetermined range to fill via-holes with copper uniformly and accurately determine the plating end point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CVS technique is used for concentration analysis of additive, then concentration measurement is performed, but by-products affect the analysis results and measurement precision deteriorates
Solution Approach 1:
The patent extracts the harmful by-products from the analysis system by using a separate reference electrode that does not generate by-products, comparing its stable potential against the working electrode to eliminate by-product interference from CVS measurements
Solution Approach 2:
The patent introduces a reference electrode as an intermediary element that provides a stable potential baseline, allowing the working electrode's potential to be measured relative to it without the interference of by-products generated during CVS analysis
2Productivity
If current density is increased to rapidly fill via-hole with metal, then plating speed increases, but void formation occurs due to improper timing
Solution Approach 1:
The patent implements feedback control by continuously monitoring the potential of the working electrode during plating and using this information to dynamically adjust the current density, ensuring void-free filling while maintaining high plating speed
Solution Approach 2:
The patent transitions from static current density control to dynamic current density adjustment based on real-time potential measurements, allowing the system to adapt to changing plating conditions and prevent void formation at critical moments
3Ease of operation
If plating end point is controlled based only on plating time, then process simplicity is maintained, but insufficient or excessive plating occurs due to process variations
Solution Approach 1:
The patent incorporates feedback control by measuring the potential of the working electrode during plating and using this information to determine the plating end point, ensuring consistent results despite variations in plating conditions
Solution Approach 2:
The patent replaces the mechanical/time-based control system with an electrochemical sensing system that measures potential to determine plating progress, substituting time-based control with real-time electrochemical feedback for more precise end point detection
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 precise control of additive concentrations, preventing voids and ensuring uniform film characteristics, while also shortening plating time by optimizing current density and determining the plating end point based on voltage changes.
Implementation Method 1
A copper plating process is widely used in a technique of manufacturing interconnects of semiconductor devices
Implementation Method 2
measuring a voltage applied to a substrate; calculating an amount of change in the voltage per predetermined time
Data Source
AI summary
A plating method capable of controlling a concentration of an additive within a proper range during plating of a substrate is disclosed. The plating method includes: disposing an anode and a substrate, having a via-hole formed in a surface thereof, so as to face each other in a plating solution containing an additive; applying a voltage between the anode and the substrate for filling the via-hole with metal; measuring the voltage applied to the substrate; calculating an amount of change in the voltage per predetermined time; and adjusting a concentration of the additive in the plating solution to keep the amount of change in the voltage within a predetermined control range.