Electrofill Vacuum Plating Cell Bubble Control
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Solution Overview
Problem
Current electroplating methods result in inconsistent feature fill and non-uniform plating due to prolonged immersion times and bubble entrapment, leading to defects and reduced plating quality, especially as the industry transitions to larger wafers.
Innovation Solution
The method involves immersing substrates in an electroplating cell under low pressure (100 Torr or less) with controlled tilt and rotation to minimize bubble formation, using a vacuum environment to facilitate quick and uniform exposure to the electrolyte, and managing dissolved gases to prevent corrosion and enhance plating uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the substrate is immersed quickly to minimize immersion time, then plating uniformity is improved, but bubble entrapment increases causing plating defects
Solution Approach 1:
The patent applies vacuum conditions (inert environment) within the electroplating cell to eliminate air bubbles and atmospheric gases that would otherwise be entrapped during substrate immersion. By maintaining vacuum pressure throughout the immersion and plating process, the harmful effect of bubble entrapment is eliminated while enabling fast immersion for improved plating uniformity.
Solution Approach 2:
The patent changes the pressure parameter from atmospheric to vacuum conditions within the electroplating cell. This parameter change fundamentally alters the bubble formation mechanism, allowing rapid immersion without bubble entrapment while maintaining plating quality and uniformity.
2Reliability
If the substrate is immersed slowly to prevent bubble entrapment, then plating quality is maintained, but immersion time becomes excessively long causing non-uniform plating
Solution Approach 1:
By creating a vacuum environment that prevents bubble formation, the patent enables rapid substrate immersion without compromising plating quality. The vacuum condition eliminates the need for slow immersion to prevent bubble entrapment, thereby reducing immersion time while maintaining reliability.
Solution Approach 2:
The vacuum condition allows continuous, uninterrupted immersion and plating operation without bubble interference. The useful action of plating can proceed continuously from the moment of immersion, eliminating the need to pause or slow down to manage bubble formation, thus optimizing both time and quality.
3Device complexity
If atmospheric pressure is used in the electroplating cell, then equipment complexity is reduced, but dissolved gases cause corrosion and non-uniform plating
Solution Approach 1:
The patent employs a vacuum environment to remove dissolved gases from the electrolyte and prevent atmospheric contamination. This eliminates corrosion and non-uniform plating caused by dissolved gases, achieving superior plating uniformity while the vacuum system integrates seamlessly with existing electroplating equipment.
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 significantly reduces bubble formation, enables faster substrate immersion, and achieves more uniform electroplating with reduced defects, improving feature fill and plating quality across the substrate surface.
Implementation Method 1
immersing the substrate in electrolyte in an electroplating cell, where the pressure in the electroplating cell during immersion is about 100 Torr or less
Implementation Method 2
electroplating material onto the substrate
Data Source
AI summary
The disclosed embodiments relate to methods and apparatus for immersing a substrate in electrolyte in an electroplating cell under sub-atmospheric conditions to reduce or eliminate the formation/trapping of bubbles as the substrate is immersed. Various electrolyte recirculation loops are disclosed to provide electrolyte to the plating cell. The recirculation loops may include pumps, degassers, sensors, valves, etc. The disclosed embodiments allow a substrate to be immersed quickly, greatly reducing the issues related to bubble formation and uneven plating times during electroplating.