Electroplating Wetting Chamber for Bubble-Free Via Wetting
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Solution Overview
Problem
Conventional wetting processes in semiconductor manufacturing fail to adequately remove air bubbles and residues from vias, leading to plating defects and impaired device performance.
Innovation Solution
A method involving the use of a gas with higher solubility than oxygen to displace air and a robust spray operation with a wetting agent to simultaneously remove bubbles and residues, utilizing a controlled atmosphere and rotational translation of the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional wetting processes are used to deposit material onto substrate surfaces, then material deposition can be achieved, but air bubbles and residues remain trapped in vias leading to plating defects
Solution Approach 1:
The substrate undergoes preliminary cleaning and drying operations before material deposition. This includes spray cleaning to remove residues and controlled atmosphere exposure to minimize bubble formation, ensuring the substrate surface is ready for defect-free plating.
Solution Approach 2:
A spray system delivers liquid cleaning agents onto the substrate surface at controlled pressures (e.g., 1-10 bar). The spray operation uses fluid dynamics to effectively remove residues and bubbles from vias and surface features through impingement and shear forces.
2Manufacturing precision
If the substrate is stationary during wetting, then process control is simplified, but uniform wetting and cleaning of all features is inadequate
Solution Approach 1:
The substrate is rotated during spray cleaning and wetting operations, transforming a static process into a dynamic one. This rotation ensures all surfaces and vias receive uniform exposure to cleaning agents and atmosphere, improving wetting consistency without requiring complex multi-axis positioning systems.
Solution Approach 2:
The rotating substrate holder serves multiple functions: it positions the substrate for uniform spray exposure, facilitates even atmosphere distribution across all features, and aids in draining excess liquid. This single mechanical motion addresses multiple process requirements simultaneously.
3Reliability
If air is not displaced from the chamber before wetting, then the process is simpler, but oxygen and other gases reduce wetting agent solubility and increase bubble formation
Solution Approach 1:
The chamber atmosphere is controlled by introducing inert or less reactive gases (e.g., nitrogen or carbon dioxide) to displace air. This creates an environment with reduced oxygen content, minimizing bubble formation and improving wetting agent performance, while using commercially available gases keeps the system relatively simple.
Solution Approach 2:
The chamber atmosphere composition is adjusted by controlling gas flow rates and pressures. By varying the partial pressures of different gases, the solubility of gases in the wetting agent is optimized, and bubble formation is minimized through parameter control rather than complex atmospheric purification.
4Strength
If spray pressure is low, then substrate damage is reduced, but bubble and residue removal effectiveness decreases
Solution Approach 1:
The substrate rotation creates dynamic exposure to the spray, allowing lower static pressures to achieve effective cleaning. The motion ensures continuous fresh spray contact and prevents liquid pooling, maintaining cleaning effectiveness at reduced pressures that are less likely to damage sensitive substrate features.
Solution Approach 2:
Instead of relying solely on high spray pressure for cleaning effectiveness, the substrate rotation adds a temporal and spatial dimension to the cleaning process. This multi-dimensional approach distributes cleaning forces more evenly and effectively removes bubbles from deep vias without requiring excessively high pressures that could damage the substrate.
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
The method significantly reduces bubble entrapment and residue presence, enhancing substrate plating uniformity and quality by ensuring complete wetting and cleaning of semiconductor features.
Implementation Method 1
forming an atmosphere in a basin housing the semiconductor substrate with a gas having a higher solubility in a wetting agent than oxygen
Implementation Method 2
wetting the plurality of features defined in the substrate
Implementation Method 3
spraying the wetting agent with a spray head onto the substrate
Data Source
AI summary
Method and systems for cleaning and wetting a semiconductor substrate, are provided. Methods and systems include forming an atmosphere in a basin housing the semiconductor substrate with a gas having a higher solubility in a wetting agent than oxygen. Methods and systems include spraying the wetting agent with a spray head onto the substrate while maintaining the atmosphere. Methods and systems include rotationally translating the semiconductor substrate, the spray head, or both the semiconductor substrate and the spray head, Methods and systems include wetting a plurality of features defined in the substrate.