3D Stress Modeling for Integrated Circuit Material Conversion
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Solution Overview
Problem
Current 3D stress modeling techniques fail to accurately model material conversions such as oxidation, silicidation, and epitaxial recrystallization in integrated circuits due to the complexity of modeling materials occupying 3D volumes and surface boundaries, leading to unreliable stress distribution estimates.
Innovation Solution
A 3D stress modeling approach that maintains the pre-conversion material boundaries and applies a strain displacement condition based on the spatial change between the pre- and post-conversion material boundaries, effectively capturing the volumetric changes and stress induced during material conversions like oxidation, silicidation, and epitaxial recrystallization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If 3D stress modeling is performed by moving material boundaries to reflect consumption and conversion, then modeling accuracy is improved, but computational reliability deteriorates due to the complexity of modeling 3D volumes and surface boundaries
Solution Approach 1:
The patent creates a copied representation of the material conversion process by introducing virtual material and virtual boundaries that mirror the physical conversion. Instead of directly modeling the complex moving boundaries of actual material conversion in 3D, the system creates a virtual copy of the process where material is consumed and virtual material is added, maintaining boundary integrity while accurately representing the physical phenomenon. This copying approach preserves modeling accuracy while ensuring computational reliability.
Solution Approach 2:
The patent introduces virtual material as an intermediary element that mediates between the consumed physical material and the newly formed material. This virtual intermediary allows the system to track material conversion without directly manipulating complex 3D boundaries, serving as a computational bridge that maintains both accuracy in representing the conversion process and reliability in numerical computation.
2Ease of manufacture
If 2D stress modeling methods are applied to 3D integrated circuits, then ease of manufacture is maintained, but modeling accuracy deteriorates due to the three-dimensional nature of stress distribution
Solution Approach 1:
The patent transitions from 2D to 3D stress modeling by introducing the third dimension (depth) into the stress analysis. The system models stress distribution throughout the full 3D volume of the integrated circuit structure, including variations in the vertical direction. This dimensional expansion captures the true three-dimensional nature of stress fields arising from material conversions, providing accurate stress predictions for deep sub-micron devices while maintaining computational tractability through the virtual material approach.
3Measurement precision
If material boundaries are moved to reflect ongoing material conversion, then modeling precision is improved, but device complexity increases due to dynamic boundary management
Solution Approach 1:
The patent segments the material conversion process into discrete computational steps by dividing the conversion into small time increments. At each increment, a portion of physical material is consumed and a corresponding amount of virtual material is added. This segmentation transforms the continuous, complex boundary movement problem into a series of discrete, manageable steps, reducing the overall computational complexity while maintaining precision in representing the material conversion.
Solution Approach 2:
The patent uses virtual material as a copied representation that simplifies boundary management. Instead of directly tracking the complex moving boundaries of actual material conversion, the system creates a virtual copy where material consumption is balanced by virtual material addition. This copying approach maintains precise representation of the conversion process while significantly reducing the complexity of boundary management through the use of fixed virtual boundaries.
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 provides accurate 3D stress modeling, enabling improved estimation of oxidation-induced stress, reducing defects, and enhancing the electrical performance and manufacturing yields of integrated circuits by accurately simulating the impact of material conversions on transistor behavior.
Implementation Method 1
an oxidant species at the oxide-ambient interface diffuses, e.g. through already formed oxide, according to the diffusion equation
Implementation Method 2
The semiconductor bulk, e.g. silicon, reacts with the dissolved oxidant at the semiconductor-oxide interface, consuming and converting semiconductor bulk material into oxide bulk material
Implementation Method 3
Because the grown oxide requires more space than the consumed semiconductor, the entire structure is deformed
Data Source
AI summary
A method, a computer medium storing computer instructions performing a method, and a computer with processor and memory perform stress modeling as follows. The stress model transforms a representation of a material conversion of a first material in the integrated circuit to a second material in the integrated circuit. Prior to the material conversion the first material occupies a first space having a first boundary. After the material conversion the first material and the second material together occupy a second space having a second boundary. The first space and the second space are different. The stress model performed by the computer system transforms the representation of the material conversion of the first material to the second material into: i) the first material occupying the first space having the first boundary, and ii) a strain displacement condition of the first material. The strain displacement condition is determined by a spatial change from the first boundary to the second boundary.