Electroplating Apparatus Ion Balance via Reverse Potential
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Solution Overview
Problem
The increasing complexity of semiconductor devices requires the formation of high-quality micro-sized metal films with 3D structures, which poses challenges in maintaining ion balance during the electroplating process, leading to inefficiencies and potential voids in the metal film.
Innovation Solution
An electroplating apparatus with a membrane dividing the electroplating bath into anode and cathode regions, utilizing a reverse potential electrode and power supply unit to apply specific potentials for electroplating and rinsing, compensating for ion concentration imbalances by reversing potentials after the electroplating process to facilitate hydrogen ion movement across the membrane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a membrane divides the electroplating bath into anode and cathode regions, then ion concentration imbalance is reduced and metal film quality is improved, but device complexity increases
Solution Approach 1:
The electroplating bath is divided into anode and cathode regions by a membrane, separating the electroplating process into distinct zones. This segmentation prevents ion concentration imbalance by controlling ion flow between regions, thereby improving metal film quality while managing the complexity through functional zonation.
Solution Approach 2:
A reverse potential electrode is introduced as an intermediary element between the anode and cathode regions. This electrode mediates the electrochemical reactions by providing an additional electron transfer pathway, which helps maintain ion balance and improves plating uniformity without requiring complete redesign of the basic electroplating structure.
2Manufacturing precision
If reverse potential is applied to compensate ion imbalance, then ion distribution is optimized and film uniformity is improved, but energy consumption increases
Solution Approach 1:
The reverse potential is applied periodically rather than continuously - specifically during rinsing cycles or at intervals during the electroplating process. This periodic application compensates for ion concentration imbalances that develop over time, maintaining film uniformity while minimizing unnecessary energy consumption by activating the reverse potential only when needed.
Solution Approach 2:
The system dynamically changes the electrical potential parameter by switching between forward potential (during active plating) and reverse potential (during compensation phases). This parameter modulation allows the system to optimize ion distribution and film uniformity while controlling energy consumption by applying reverse potential only during specific process stages rather than continuously.
3Manufacturing precision
If reverse anode potential is applied during rinsing, then hydrogen ions move across membrane and ion balance is maintained, but process time increases
Solution Approach 1:
The reverse anode potential is applied during the rinsing phase, which occurs after the main electroplating process. By performing the ion balance compensation during this preliminary/post-processing stage rather than extending the main plating time, the system maintains ion balance without significantly increasing the critical metal film formation time.
Solution Approach 2:
The reverse potential application during rinsing continues the useful action of ion transport and balance maintenance without interrupting the overall process flow. The rinsing phase itself is a necessary step, and applying reverse potential during this time utilizes otherwise idle period to perform additional ion balancing, effectively maintaining ion balance without adding net process time.
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 approach ensures the formation of metal films with excellent characteristics by maintaining ion balance, preventing voids and discoloration, and reducing process expenses by optimizing ion distribution and solution usage.
Implementation Method 1
The electroplating bath includes a membrane dividing the electroplating bath into an anode region and a cathode region
Implementation Method 2
The metal ions in the electroplating solution may be precipitated on the wafer and a metal film may be formed by immersing a wafer in an electroplating bath including an electroplating solution containing metal ions and providing a current thereto
Implementation Method 3
an electroplating apparatus capable of electro-deposition to form a metal film on a wafer
Implementation Method 4
compensating for ion concentration imbalances by reversing potentials after the electroplating process to facilitate hydrogen ion movement across the membrane
Data Source
AI summary
An electroplating apparatus includes: an electroplating bath including an anode region, in which an anode electrode is arranged, a cathode region and a membrane; a head unit including a contact ring holding a wafer and configured so that a first cathode potential is applied to the contact ring during an electroplating process; a reverse potential electrode arranged adjacent to the membrane and configured so that a second cathode potential is applied to the reverse potential electrode during the electroplating process, and a reverse cathode potential is applied to the reverse potential electrode during a rinsing process; and a power supply unit configured to apply the first cathode potential and the second cathode potential during the electroplating process, and further configured to apply the reverse cathode potential and a reverse anode potential to the anode electrode during the rinsing process.