Dynamic-Angle Plasma Etch for Interconnect Alignment
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Solution Overview
Problem
Existing methods for fabricating integrated circuits face challenges in developing improved dielectric and metal interconnection structures, particularly in scaling down processes that increase complexity and require advancements in wiring and interconnects between transistors and other devices.
Innovation Solution
The method involves a dynamic-angle plasma etch process to form interconnect features with varying etching biases along different directions, allowing for a larger overlap and flexibility in connecting substrate and material features, thereby enhancing the interconnection structure and critical dimension design budget.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching processes are used to fabricate interconnect features, then the manufacturing process is simpler, but the alignment precision and critical dimension control deteriorate
Solution Approach 1:
The patent employs a dynamic-angle plasma etch process where the angle of incidence of the plasma flux is varied during the etching operation. This dynamic adjustment allows different etching biases to be applied in different directions, enabling precise control over the critical dimensions and alignment of interconnect features while managing process complexity through controlled variability.
Solution Approach 2:
The invention changes physical parameters of the etching process, specifically the angle of incidence of plasma flux, to achieve varying etching biases along different directions. By modifying this parameter dynamically, the process achieves improved alignment precision and critical dimension control without requiring entirely new fabrication methodologies.
2Productivity
If feature size is reduced to increase functional density, then production efficiency improves, but manufacturing precision and alignment become more difficult
Solution Approach 1:
By implementing dynamic-angle etching, the process can compensate for alignment variations that become more significant at smaller feature sizes. The varying angle of incidence allows for adjusted etching profiles that maintain precision even as feature dimensions decrease, thereby supporting higher functional density without sacrificing alignment quality.
Solution Approach 2:
The patent modifies etching parameters dynamically to maintain manufacturing precision at reduced feature sizes. By adjusting the plasma flux angle during etching, the process achieves the necessary precision for smaller features while maintaining production efficiency gains from scaling.
3Manufacturing precision
If overlay area is increased to improve alignment, then manufacturing precision improves, but device area and complexity increase
Solution Approach 1:
The dynamic-angle plasma etch process achieves improved alignment precision through controlled variation of etching conditions rather than through increased overlay area. This approach maintains structural simplicity while achieving the desired alignment precision through process control.
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 results in a robust interconnection structure with improved alignment and reduced resistance, increasing the critical dimension design budget and manufacturing efficiency by providing a larger overlay area and relaxing feature size constraints.
Implementation Method 1
A dynamic-angle plasma etch process is used to form openings through the dielectric layer
Data Source
AI summary
A method includes receiving a substrate having a substrate feature; forming a first material layer over the substrate and in physical contact with the substrate feature; forming an etch mask over the first material layer; and applying a dynamic-angle (DA) plasma etching process to the first material layer through the etch mask to form a first material feature. Plasma flux of the DA plasma etching process has an angle of incidence with respect to a normal of the first material layer and the angle of incidence changes in a dynamic mode during the DA plasma etching process.