Dual Pulse Electroplating for Void-Free Copper Plugs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in semiconductor manufacturing is the difficulty in metal electroplating, particularly copper electroplating, due to void formation in copper plugs, leading to low process capability, low yield, and increased risk of EM failures, as dimensions decrease in semiconductor devices.
Innovation Solution
A method involving dual pulse power and ultrasonic waves is applied during metal electroplating, with specific frequency and power settings, to improve gap filling in trenches and holes, and prevent void formation by enhancing copper ion distribution and plating quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional metal electroplating is used in backend process, then the process is simple and easy to implement, but voids are incurred in copper plugs leading to low yield and reliability issues
Solution Approach 1:
The patent applies dual pulse power with periodic forward and inverse pulses during electroplating. The forward pulse deposits metal while the inverse pulse removes excess metal and prevents void formation. This periodic action continues throughout the electroplating process, ensuring uniform metal deposition without voids in the copper plugs.
Solution Approach 2:
The patent introduces ultrasonic vibration during the electroplating process. The ultrasonic wave frequency (20-100 kHz) creates mechanical vibration that enhances metal ion distribution and prevents void formation. The vibration energy helps eliminate trapped gases and ensures uniform metal deposition in the openings.
2Length of moving object
If via and trench dimensions are reduced in backend process, then the critical dimension is reduced for higher device density, but metal electroplating becomes increasingly difficult
Solution Approach 1:
The patent changes multiple parameters during electroplating: dual pulse power parameters (frequency 1800-5000 Hz, forward-pulse current to inverse-pulse current ratio 5:1 to 10:1, forward-pulse duration to inverse-pulse duration ratio 10:1 to 20:1), ultrasonic wave parameters (frequency 1000-5000 Hz, power 50-1500 W). These parameter changes enable effective electroplating in reduced dimensions while preventing void formation.
Solution Approach 2:
The dual pulse power applies periodic forward and inverse pulses at specific frequencies (1800-5000 Hz). The forward pulse deposits metal and the inverse pulse removes excess metal, creating a self-regulating process that works effectively in small via and trench dimensions. This periodic action ensures uniform deposition even in high-aspect-ratio structures.
3Manufacturing precision
If conventional electroplating process is used, then the process flow is short and simple, but gap filling for holes and trenches is poor
Solution Approach 1:
The dual pulse power process uses periodic forward and inverse pulses to achieve superior gap filling. The forward pulse deposits metal on the opening walls and bottom, while the inverse pulse removes excess metal and prevents protrusion at corners. This periodic deposition and removal cycle ensures uniform gap filling in holes and trenches.
Solution Approach 2:
Ultrasonic vibration (frequency 1000-5000 Hz, power 50-1500 W) is applied during electroplating to enhance gap filling. The mechanical vibration energy promotes uniform metal ion distribution in the electroplating solution, ensuring complete and uniform filling of high-aspect-ratio holes and trenches without voids.
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 increases the wafer acceptance test pass rate, improves yield, and enhances the reliability of semiconductor devices by effectively suppressing voids and improving the electroplating process.
Implementation Method 1
applying a dual pulse power to the semiconductor device during metal electroplating a part of the semiconductor device to be electroplated
Implementation Method 2
applying ultrasonic wave to said semiconductor device in the metal electroplating
Data Source
AI summary
A method for manufacturing semiconductor device comprises: applying a dual pulse power to the semiconductor device during metal electroplating a part of the semiconductor device to be electroplated, and applying ultrasonic wave to said semiconductor device in the metal electroplating.