Inert Anode Electroplating Processor with Anionic Membrane Ion Balance
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Solution Overview
Problem
The complexity and cost associated with consumable anodes in electroplating processors, along with inefficiencies and defects caused by inert anodes, pose challenges in maintaining metal ion concentration and stability during the electroplating process for semiconductor integrated circuits and micro-scale devices.
Innovation Solution
An electroplating processor design featuring a vessel with a processor anionic membrane separating two compartments, one for catholyte and the other for anolyte, utilizing inert anodes and a replenisher system with anionic membranes to balance ion concentrations by circulating electrolytes and introducing metal ions from a bulk source, eliminating the need for additional compartments and intermediate electrolytes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If consumable anodes are used to replenish metal ions, then metal ion concentration is maintained, but device complexity and maintenance cost increase
Solution Approach 1:
The patent uses disposable consumable anodes that are periodically replaced to replenish metal ions in the electrolyte bath. These inexpensive sacrificial anodes dissolve during electroplating, releasing metal ions that plate onto the wafer, maintaining bath composition without requiring complex replenishment systems.
Solution Approach 2:
The system discards spent consumable anodes and recovers metal ions through the electroplating process itself. The anodes are intentionally consumed during operation, and the metal ions they release are recovered as plated material on the wafer, creating a self-sustaining cycle.
2Reliability
If consumable anodes are combined with cationic membranes to avoid degradation, then anode stability improves, but metal ion replenishment efficiency decreases
Solution Approach 1:
The patent extracts the membrane component from the system entirely, operating without any membrane between the anode and cathode compartments. This eliminates the barrier that would block metal ion transport, allowing consumable anodes to efficiently replenish metal ions in the electrolyte without membrane-induced resistance.
Solution Approach 2:
Instead of using a cationic membrane to prevent anode degradation (which blocks ion flow), the patent inverts the approach by using consumable anodes that are designed to be replaced periodically. This eliminates the need for membranes entirely, as the simplicity of consumable anode replacement outweighs the protection membranes would provide.
3Device complexity
If inert anodes are used to reduce complexity, then maintenance cost decreases, but metal ion concentration control becomes less effective
Solution Approach 1:
The patent employs inexpensive consumable anodes that are periodically replaced rather than using expensive inert anodes. These sacrificial anodes continuously replenish metal ions in the electrolyte bath through controlled dissolution, maintaining stable metal ion concentration without requiring complex external replenishment systems.
Solution Approach 2:
The consumable anodes perform self-service by automatically replenishing metal ions in the electrolyte bath through their own dissolution during electroplating. As current passes through the cell, the anodes corrode and release metal ions that plate onto the wafer, creating a self-regulating system that maintains bath composition.
4Device complexity
If inert anodes are used to simplify the system, then maintenance requirements reduce, but gas generation causes wafer defects
Solution Approach 1:
The patent uses consumable metal anodes instead of inert anodes to avoid gas generation problems. The consumable anodes undergo controlled dissolution rather than water electrolysis, eliminating harmful gas bubbles that would adhere to wafers and cause defects, while remaining inexpensive and simple to replace.
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 simplifies maintenance, reduces costs, and maintains efficient metal ion concentration, minimizing defects by using a single membrane and compartment system, ensuring stable and balanced ion concentrations for effective electroplating.
Implementation Method 1
an anionic membrane between them... Anions, such as sulfate ions in the case of plating copper, move from the anolyte in the second replenisher compartment, through the anionic membrane, and into the catholyte in the first replenisher compartment
Implementation Method 2
Metal ions in the electrolyte plate out onto the wafer, creating a metal layer on the wafer
Implementation Method 3
Metal ions in the electrolyte plate out onto the wafer, creating a metal layer on the wafer
Implementation Method 4
Electrical current is passed through the electrolyte and the conductive layer
Data Source
AI summary
An electroplating system includes a processor has a vessel having a first or upper compartment and a second or lower compartment containing catholyte and anolyte, respectively, with an processor anionic membrane between them. An inert anode is located in the second compartment. A replenisher is connected to the vessel via catholyte return and supply lines and anolyte return and supply lines, to circulate catholyte and anolyte through compartments in the replenisher separated by a replenisher anionic membrane. The replenisher adds metal ions into the catholyte by moving ions from a bulk metal source, and moves anions from the anolyte through the anionic membrane and into the catholyte. Concentrations or metal ions and anions in the catholyte and the anolyte remain balanced.