Hydrophobic Base Plate for Electroplating Edge Defects
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Solution Overview
Problem
Existing electroplating apparatuses in semiconductor fabrication suffer from contamination of plating solution, leading to edge defects and frequent maintenance due to electrolyte wicking into electrical contacts, which degrades performance and causes particle contamination.
Innovation Solution
A base plate with a hydrophobic coating, including polyamide-imide (PAI) and polytetrafluoroethylene (PTFE), is used to minimize electrolyte wicking, combined with a ring-shaped body and knife-shaped protrusion to support an elastomeric lipseal, excluding electroplating solution from electrical contacts, and a contact ring with angled fingers to reduce contact with the wafer edge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional base plates are used without hydrophobic coating, then electrolyte can reach electrical contacts causing contamination, but the structure is simpler and manufacturing is easier
Solution Approach 1:
The base plate surface property is changed from hydrophilic to hydrophobic through coating application. This parameter change prevents electrolyte wicking into electrical contacts by creating a water-repellent surface, thereby maintaining electrical contact performance without requiring fundamental structural redesign
Solution Approach 2:
A hydrophobic coating layer is introduced as an intermediary between the base plate and the electrolyte. This coating acts as a barrier that prevents direct contact between the electrolyte and the electrical contacts, eliminating contamination while keeping the base plate structure relatively simple
2Reliability
If lipseals are used to exclude electrolyte from contacts, then contact contamination is reduced, but electrolyte still wicks into contact area causing edge defects
Solution Approach 1:
The surface energy characteristic of the base plate is changed from hydrophilic to hydrophobic through coating. This prevents capillary action that causes electrolyte wicking into the contact area, thereby eliminating edge defects while the lipseal maintains its protective function
3Productivity
If multiple plating cycles are performed, then production volume increases, but electrolyte contamination accumulates causing performance degradation
Solution Approach 1:
The hydrophobic coating is applied in advance to the base plate before plating operations begin. This preliminary protective measure ensures that as plating cycles accumulate, electrolyte cannot wick into the contact area, preventing contamination buildup and maintaining reliable contact performance throughout extended production runs
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 configuration significantly reduces wafer edge defects by over 80% and decreases maintenance frequency, maintaining performance even as lipseals age, by effectively preventing electrolyte from reaching sensitive components.
Implementation Method 1
A base plate with a hydrophobic coating covering at least a portion of the plate exposed to electrolyte is used to minimize rinsate and electrolyte wicking into the contact area of the clamshell
Data Source
AI summary
Methods, apparatuses, and various apparatus components, such as base plates, lipseals, and contact ring assemblies are provided for reducing contamination of the contact area in the apparatuses. Contamination may happen during removal of semiconductor wafers from apparatuses after the electroplating process. In certain embodiments, a base plate with a hydrophobic coating, such as polyamide-imide (PAI) and sometimes polytetrafluoroethylene (PTFE), are used. Further, contact tips of the contact ring assembly may be positioned further away from the sealing lip of the lipseal. In certain embodiments, a portion of the contact ring assembly and/or the lipseal also include hydrophobic coatings.