Wafer Support Apparatus for Electroplating Current Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The electroplating process for semiconductor wafers faces challenges in achieving uniform material deposition due to variations in electrical current distribution and exposure of electrical connections to the electroplating solution, leading to non-uniformities and fringing effects.
Innovation Solution
A multi-layered wafer handling system with embedded contact circuitry and sacrificial anodes is used to establish independent electrical connections and maintain a liquid seal, ensuring uniform current distribution and preventing exposure of connections to the electroplating solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional electroplating setup is used with direct electrical contacts, then electrical connection is established, but non-uniform current distribution and fringing effects occur leading to poor deposition uniformity
Solution Approach 1:
The patent introduces an intermediary wafer support structure with embedded conductive traces and contact pads that mediates between the power source and the wafer. This intermediary structure distributes current uniformly across the wafer surface through carefully designed trace patterns, eliminating the fringing effects and non-uniform current distribution that occur with direct electrical contacts.
Solution Approach 2:
The patent replaces traditional mechanical electrical contact methods (such as point contacts or edge contacts) with an integrated circuit board-based electrical connection system. The conductive traces and contact pads embedded in the wafer support structure provide distributed electrical contact across multiple points, substituting simple mechanical contact with a more sophisticated electrical distribution network that ensures uniform current flow.
2Manufacturing precision
If electrical connections are exposed to electroplating solution, then electrical contact is maintained, but contamination and non-uniform deposition occur
Solution Approach 1:
The patent employs a thin film or flexible membrane structure that covers the electrical connections and separates them from the electroplating solution. This thin film barrier allows electrical signals to pass through while preventing direct contact between the solution and electrical contacts, thereby avoiding contamination and the associated non-uniform deposition effects.
Solution Approach 2:
The patent addresses the exposure problem by transitioning from a planar configuration where electrical contacts are in the same plane as the wafer surface to a multi-dimensional structure. The electrical connections are routed through or beneath the wafer support structure, placing them in a different spatial dimension that is protected from solution exposure while maintaining electrical functionality.
3Manufacturing precision
If simple wafer support structure is used, then ease of manufacture is improved, but uniform current distribution and liquid seal cannot be achieved
Solution Approach 1:
The patent divides the wafer support structure into multiple functional segments: a support substrate, embedded conductive traces, contact pads, and sealing regions. This segmentation allows each component to be optimized independently for its specific function while being integrated into a unified structure that achieves both uniform current distribution and effective liquid sealing.
Solution Approach 2:
The patent utilizes composite material structures combining conductive materials (for current distribution) with insulating or sealing materials (for liquid barrier functionality). This composite approach enables a single integrated component to perform multiple functions - electrical conduction, mechanical support, and solution sealing - without requiring separate complex assemblies.
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 solution achieves uniform material deposition across the wafer surface by controlling electrical current profiles and minimizing fringing effects, resulting in consistent electroplating results.
Implementation Method 1
In the electroplating process, an electrolyte is disposed between an anode and the wafer surface to be electroplated. Additionally, the wafer surface to be electroplated is maintained at a lower voltage potential than the anode. As an electric current flows through the electrolyte from the anode to the wafer surface, electroplating reactions occurring at the wafer surface cause material to be deposited on the wafer surface.
Implementation Method 2
The top film layer is defined to provide a liquid seal between the top film layer and the wafer, about a periphery of the open region.
Data Source
AI summary
A multi-layered wafer support apparatus is provided for performing an electroplating process on a semiconductor wafer (“wafer”). The multi-layered wafer support apparatus includes a bottom film layer and a top film layer. The bottom film layer includes a wafer placement area and a sacrificial anode surrounding the wafer placement area. The top film layer is defined to be placed over the bottom film layer. The top film layer includes an open region to be positioned over a surface of the wafer to be processed, i.e., electroplated. The top film layer provides a liquid seal between the top film layer and the wafer, about a periphery of the open region. The top film layer further includes first and second electrical circuits that are each defined to electrically contact a peripheral top surface of the wafer at diametrically opposed locations about the wafer.