Electrolyte Loop Pressure Regulator for TSV Plating
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Solution Overview
Problem
The electroplating process for through-silicon vias (TSVs) in semiconductor manufacturing faces challenges due to the large size and high aspect ratio of TSVs, leading to non-uniformity and membrane damage caused by pressure differentials and electroosmotic effects in separated anode and cathode chambers, which increases costs and complexity with existing pressure regulation methods.
Innovation Solution
An open loop recirculation system with a pressure regulator maintains a constant pressure in the anode chamber, using a vertical column and filter to prevent bubble entrapment and pressure fluctuations, allowing ionic species passage while blocking non-ionic additives, and includes a controller for level management and make-up solution delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a membrane is used to separate anode and cathode chambers, then metal deposition uniformity is improved, but membrane damage occurs due to pressure differentials and electroosmotic effects
Solution Approach 1:
A pressure regulator is introduced as an intermediary component between the anode chamber and the electrolyte recirculation system. The pressure regulator includes a vertical column with a top opening exposed to atmospheric pressure, which mediates pressure differentials and prevents direct transmission of pressure fluctuations to the membrane, thereby preventing membrane damage while maintaining deposition uniformity.
Solution Approach 2:
The harmful pressure differential and electroosmotic effects are extracted and isolated from the membrane separation zone by introducing the pressure regulator with its vertical column. The pressure regulator creates a pressure equalization path that removes the harmful pressure gradients from the membrane area, allowing the membrane to function without damage.
2Reliability
If pressure regulation is implemented to prevent membrane damage, then device complexity and cost increase due to precise pumps and pressure sensors
Solution Approach 1:
The pressure regulator is designed to be self-regulating through its simple vertical column structure exposed to atmospheric pressure. The system automatically equalizes pressure without requiring external control mechanisms, precise pumps, or pressure sensors. The electrolyte level in the vertical column naturally adjusts to maintain pressure equilibrium, making the system self-service and eliminating complex control systems.
Solution Approach 2:
The pressure regulator uses a simple, inexpensive vertical column structure that can be easily manufactured and replaced if needed. This simple mechanical design replaces expensive precision pumps and sensors, significantly reducing device complexity and cost while achieving the same reliability goal.
3Productivity
If pressure differentials are allowed to develop in separated chambers, then electroplating efficiency is maintained, but non-uniform plating and membrane damage occur
Solution Approach 1:
The pressure regulator acts as an intermediary that allows pressure differentials to exist in the electroplating chambers for maintaining plating efficiency, while simultaneously equalizing the pressure at the membrane interface. The vertical column with atmospheric pressure exposure serves as a mediator that decouples the pressure driving electroplating from the pressure that would damage the membrane, enabling both efficiency and uniformity.
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 solution reduces membrane damage, maintains uniform electroplating, and decreases costs by eliminating the need for precise pumps and pressure sensors, enhancing the efficiency and reliability of the electroplating process.
Implementation Method 1
The pressure regulator includes a vertical column arranged to provide pressure head that maintains the electrolyte in the anode chamber at a substantially constant pressure
Implementation Method 2
The recirculation system may include a filter fitted around the outside of the vertical column
Implementation Method 3
The membrane may be used to block the insoluble particles, which reduces interference with the metal deposition and contamination of the wafer
Implementation Method 4
An electric field generated by the applied voltage electrochemically reduces metal ions at the cathode. As a result, metal is plated on the seed layer
Implementation Method 5
a pump located outside the anode chamber and configured to draw electrolyte out of the pressure regulating device and force it into the separated anode chamber
Data Source
AI summary
An electrolyte, and particularly anolyte, may be circulated via an open loop having a pressure regulator, so that the pressure in the plating chamber is maintained at a constant (or substantially constant) value with respect to atmospheric pressure. In these embodiments, a pressure regulator is in fluid communication with the anode chamber.