Metal Silicide Contact Formation With Plasma Oxygen Isolation
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Solution Overview
Problem
The traditional semiconductor manufacturing process for cobalt interconnects often results in the formation of an oxide layer due to atmospheric oxygen, increasing contact resistance and potentially leading to open circuits, and requires costly titanium targets for oxygen isolation.
Innovation Solution
A method involving the formation of a contact metal layer on a silicon substrate, followed by a plasma treatment to create an oxygen isolation layer, which reduces oxide formation during silicidation, thereby lowering contact resistance and improving device yield without using titanium targets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional atmospheric oxygen exposure is used during cobalt deposition, then the process is simple, but an oxide layer forms on the cobalt silicide surface increasing contact resistance
Solution Approach 1:
The patent applies preliminary action by forming an oxygen isolation layer on the cobalt film surface before the silicidation process. This isolation layer is created in advance to prevent oxygen from reaching the cobalt silicide during subsequent high-temperature annealing, thereby preventing oxide formation and maintaining low contact resistance without complicating the overall process flow
Solution Approach 2:
The patent introduces an oxygen isolation layer as an intermediary substance between the atmospheric oxygen and the cobalt film. This intermediate layer acts as a barrier that selectively blocks oxygen while allowing the silicidation process to proceed, thus protecting the cobalt silicide from oxidation without requiring complex process changes
2Reliability
If titanium targets are used for oxygen isolation, then oxide formation is prevented, but production costs increase
Solution Approach 1:
The patent replaces expensive titanium targets with a cost-effective oxygen isolation layer formed from abundant materials. The isolation layer is designed to be thin and consumable, serving its protective function during the silicidation process and then being removed or integrated into the final structure, thereby significantly reducing material costs while maintaining reliable contact resistance
Solution Approach 2:
The patent changes the material parameters by substituting titanium with alternative materials that are less expensive and equally effective at oxygen isolation. By adjusting the composition and thickness parameters of the isolation layer, the patent achieves the same protective function at lower cost, eliminating the need for costly titanium targets
3Manufacturing precision
If high-temperature thermal annealing is performed in atmospheric oxygen, then cobalt silicide is formed, but oxide layer formation increases contact resistance
Solution Approach 1:
The patent applies preliminary action by pre-forming the oxygen isolation layer before the high-temperature annealing process. This isolation layer is prepared in advance to protect the cobalt film during the subsequent silicidation annealing, ensuring that oxide formation is prevented while the silicidation reaction completes successfully, thereby maintaining both manufacturing precision and low contact resistance
Solution Approach 2:
The patent introduces an oxygen isolation layer as an intermediary barrier between the atmospheric oxygen and the cobalt film during high-temperature annealing. This intermediate layer allows the silicidation reaction to proceed to completion while blocking oxygen from reaching the cobalt silicide surface, thus preventing oxide formation and maintaining low contact resistance without interfering with the silicidation process
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 method effectively reduces oxide defects in metal-non-metal interconnects, simplifies the process, and decreases production costs by eliminating the need for titanium targets while maintaining device performance.
Implementation Method 1
performing a plasma treatment process, and forming an oxygen isolation layer on a surface of the contact metal layer
Implementation Method 2
performing a silicidation reaction process, and converting the contact metal layer into a metal silicide layer
Data Source
AI summary
Embodiments of the present application relate to a method for manufacturing a semiconductor structure, includes: forming a contact metal layer on a silicon substrate; performing a plasma treatment process, and forming an oxygen isolation layer on a surface of the contact metal layer; and performing a silicidation reaction process, and converting the contact metal layer into a metal silicide layer.