Wafer Side Polymer Coating for Damascene Layer Control
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Solution Overview
Problem
Existing semiconductor wafer processing techniques fail to effectively prevent the electrodeposited damascene layer from forming on the side/bevel of the wafer during BEOL processing, leading to undesirable extensions onto the wafer's circumferential side.
Innovation Solution
A system is implemented that applies a polymer coating to the side of the wafer using an electrophoresis technique, driven by a power supply, which acts as a barrier to the formation of the damascene layer, and includes a heat source for thermal curing of the polymer coating, ensuring it covers only the side and optionally a portion of the front and back surfaces, thereby preventing the layer's extension onto the side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electroplating is performed to form the damascene layer, then the conductive interconnect structure is formed, but the electrodeposited layer extends onto the side of the wafer which is undesirable
Solution Approach 1:
A polymer coating is applied as an intermediary barrier layer between the electroplating bath and the wafer side surface. This polymer layer prevents copper ions from depositing on the wafer side while allowing the electroplating process to proceed normally on the front surface, thus eliminating the harmful extension of the electrodeposited layer onto the wafer side.
Solution Approach 2:
The polymer coating is applied to the wafer side surface before the electroplating process begins. This preliminary protective action prevents the unwanted deposition of copper on the wafer side by creating a barrier that repels or blocks the electrodeposited material, thereby preventing the harmful effect before it can occur.
2Object-generated harmful factors
If a polymer coating is applied to protect the wafer side, then the extension of electrodeposited layer is prevented, but the processing complexity increases
Solution Approach 1:
The polymer coating application step is integrated with the existing electroplating process flow, combining the protective function with the deposition process. The polymer coating is applied and then the electroplating is performed in sequence without requiring separate complex equipment or processes, thus preventing the harmful effect while minimizing the increase in processing complexity.
Solution Approach 2:
The polymer coating used is a temporary, disposable protective layer that is applied specifically for the electroplating process and then removed or left as a thin residue. This approach uses a simple, inexpensive polymer layer that serves its protective purpose during electroplating and is then discarded, avoiding the need for complex, permanent protective structures.
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 polymer coating effectively prevents the electrodeposited damascene layer from forming on the wafer's side, maintaining the integrity of the bevel and ensuring precise control over the layer's deposition, enhancing the overall processing efficiency and accuracy.
Implementation Method 1
an arrangement configured to apply a polymer coating to the side of the wafer before electroplating the damascene layer, with the system being configured to apply the polymer coating in accordance with an electrophoresis technique driven by the power supply
Implementation Method 2
the heat source is configured to thermally cure the polymer liquid coating the side of the wafer to thereby form the polymer coating
Implementation Method 3
a semiconductor wafer including opposing, major front and back surfaces joined by a circumferential side, with the wafer undergoing back-end-of-line (BEOL) processing including electroplating a damascene layer on the wafer
Data Source
AI summary
A system is provided that includes a power supply connectable to a semiconductor wafer including opposing, major front and back surfaces joined by a circumferential side, with the wafer undergoing processing including electroplating a damascene layer on the wafer. The system also includes an arrangement configured to apply a polymer coating to the side of the wafer before electroplating the damascene layer, with the system being configured to apply the polymer coating in accordance with an electrophoresis technique driven by the power supply. In this regard, the polymer coating is applied to the side but not at least a portion of the front and back surfaces of the wafer, and the polymer coating provides a barrier to formation of the damascene layer on the side of the wafer.