Electroplating Apparatus with Internally Irrigated Catholyte Chambers
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Solution Overview
Problem
Existing electroplating technologies face challenges in achieving low defect density during the deposition of electrically conductive materials on semiconductor wafers, particularly due to issues like anode passivation, precipitation of metal ion salts, and local concentration of reactive species near the membrane surface, leading to membrane blockage and defects on the wafer.
Innovation Solution
The electroplating apparatus incorporates a catholyte chamber with a mechanism for strong internal mixing and flow distribution tubes to enhance convective flow near the cationic membrane, preventing deleterious effects such as precipitation and electrodeposition of films, thereby reducing defects and improving operational conditions like current, salt concentrations, and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional electroplating is used without internal mixing mechanisms, then the apparatus structure is simple, but defect density on wafers is high due to anode passivation and metal ion salt precipitation
Solution Approach 1:
The electroplating chamber is divided into multiple independently irrigated chambers, each with its own flow distribution tubes and internal mixing mechanisms. This segmentation allows localized control of electrolyte flow and concentration, preventing metal ion salt precipitation and anode passivation while maintaining overall system manageability.
Solution Approach 2:
The patent employs hydraulic flow distribution tubes that deliver electrolyte to specific locations within the chamber. The flow distribution tubes create turbulent flow patterns that enhance mass transfer, prevent concentration polarization, and eliminate precipitation and passivation issues without requiring complex mechanical mixing devices.
2Reliability
If internal mixing mechanisms are added to prevent precipitation and passivation, then operational stability improves, but device complexity increases
Solution Approach 1:
The flow distribution tubes are designed to automatically create turbulent flow patterns and internal mixing without external control systems. The electrolyte flow itself generates the mixing action through proper tube configuration and positioning, eliminating the need for separate pumps, agitators, or control mechanisms while maintaining operational stability.
Solution Approach 2:
The patent changes the flow regime parameter from laminar to turbulent flow by optimizing flow distribution tube configurations. This parameter change naturally enhances mass transfer coefficients, prevents concentration polarization, and eliminates precipitation and passivation issues without adding complex control systems.
3Stability of the object's composition
If conventional flow distribution is used, then the apparatus is simple, but convection near the membrane is insufficient leading to local concentration of reactive species
Solution Approach 1:
The flow distribution tubes are strategically positioned to deliver electrolyte specifically to regions near the membrane where concentration polarization occurs. This localized irrigation creates high-velocity turbulent flow exactly where it is needed to prevent reactive species accumulation, while other regions of the chamber maintain simpler flow patterns.
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 design results in a significant reduction in wafer defects, approximately 46%, and allows for a wider operational range, including higher currents and lower temperatures, while maintaining long-term stability and reducing maintenance needs.
Implementation Method 1
The catholyte manifold and the at least one flow distribution tube are configured to increase convection of an electrolyte at the membrane
Implementation Method 2
a current is supplied to the work piece to plate the metal layer onto the work piece surface
Data Source
AI summary
An apparatus for electroplating a layer of metal onto a work piece surface includes a membrane separating the chamber of the apparatus into a catholyte chamber and an anolyte chamber. In the catholyte chamber is a catholyte manifold region that includes a catholyte manifold and at least one flow distribution tube. The catholyte manifold and at least one flow distribution tube serve to mix and direct catholyte flow in the catholyte chamber. The provided configuration effectively reduces failure and improves the operational ranges of the apparatus.