Overlapping Transistor Stressors for Package Stress Compensation
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Solution Overview
Problem
Integrated circuits face challenges in maintaining consistent transistor performance due to varying stress imparted by package structures, which can affect carrier mobility and drive current.
Innovation Solution
The use of overlapping compressive and tensile stressors directly over active transistor regions allows for adjustment of stress applied to the channel region to compensate for package structure stress, without requiring additional masks or implantation steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If package structures are used to support the integrated circuit, then mechanical strength and structural stability are improved, but stress variations are introduced that affect transistor performance
Solution Approach 1:
The patent applies preliminary anti-action by forming compensation stressors that generate stress opposite to the expected stress from package structures. The compensation stressors are configured to pre-counteract the package-induced stress variations, thereby maintaining consistent transistor performance despite the mechanical support provided by the package structures.
Solution Approach 2:
The patent implements local quality by selectively placing compensation stressors at specific locations where package-induced stress variations occur. Each compensation stressor is positioned and configured to address local stress conditions, allowing different regions of the integrated circuit to have tailored stress compensation while maintaining overall structural integrity.
2Ease of manufacture
If traditional stressor formation methods are used, then process simplicity is maintained, but the ability to compensate for package structure stress is insufficient
Solution Approach 1:
The patent merges stressor formation with existing manufacturing processes by integrating the formation of compensation stressors into the existing stressor formation sequence. The compensation stressors are formed using the same deposition and patterning processes as traditional stressors, combining stress compensation functionality with standard manufacturing workflows without requiring separate process lines.
Solution Approach 2:
The patent achieves universality by designing compensation stressors that can be formed using the same materials and processes as traditional stressors. The compensation stressors serve dual purposes: they provide the intended stress to their underlying transistor regions while simultaneously compensating for package-induced stress variations across the integrated circuit.
3Manufacturing precision
If stressors are added to compensate for package stress, then transistor performance consistency is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the integrated circuit into distinct regions based on package-induced stress patterns. Compensation stressors are selectively placed in specific regions where stress compensation is needed, rather than uniformly across the entire circuit. This segmented approach maintains performance consistency while minimizing the overall number of compensation stressors required.
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 enables individual adjustment of channel stresses across the integrated circuit, reducing variations in carrier mobility and drive current, and improving overall integrated circuit performance.
Implementation Method 1
A stressor is a dielectric structure that is formed to induce a stress (either compressive or tensile) on surrounding structures of an integrated circuit
Data Source
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AI summary
An integrated circuit includes a compressive stressor and a tensile stressor, each located directly over an active region of a transistor, where a portion of the compressive stressor and a portion of the tensile stressor directly overlap with each other. In some embodiments, utilizing a compressive stressor and tensile stressor located directly over an active region with overlapping portions may allow for an adjustment of the stress applied to a channel region of a transistor to compensate for stress imparted by package structures.