Semiconductor Layer Uniaxial Stress Transfer Without Strip Cutting
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Solution Overview
Problem
Existing methods for creating uniaxial stress in semiconductor layers for CMOS transistors on FDSOI substrates result in material loss and reduced integration density, as they require post-stress modification steps like strip cutting, which is material-intensive and inefficient.
Innovation Solution
A method involving a stack with a substrate, semiconductor layer, and a fusible layer, followed by a stress-donating layer, where a partial alteration of the stress-donating layer modifies the stress state before melting the fusible layer, directly transferring a uniaxial stress to the semiconductor layer, eliminating the need for post-stress modification steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If strip cutting is used to obtain uniaxial stress, then uniaxial stress state is achieved, but material loss occurs and integration density is reduced
Solution Approach 1:
The stress-donating layer is patterned and partially altered before the fusible layer melting step, so that the uniaxial stress state is pre-configured in the stress-donating layer. This preliminary action eliminates the need for post-stress modification steps like strip cutting, thereby preventing material loss while achieving the desired stress state.
Solution Approach 2:
The invention extracts and eliminates the unnecessary strip cutting step from the conventional process. By transferring the uniaxial stress state upstream to the stress-donating layer before fusible layer melting, the method removes the material-intensive post-processing step that causes integration density reduction.
2Stress or pressure
If biaxial stress state is transferred to semiconductor layer, then stress is applied, but crystal defects occur and layer thickness is limited
Solution Approach 1:
The stress-donating layer is partially altered in specific regions to create localized uniaxial stress states. By selectively modifying only the necessary portions of the stress-donating layer, the method achieves precise stress control that applies stress intensity where needed while avoiding the generation of crystal defects in the semiconductor layer, thus allowing greater layer thickness.
3Manufacturing precision
If post-stress modification steps are implemented, then uniaxial stress is achieved, but process complexity and material consumption increase
Solution Approach 1:
The uniaxial stress state is configured in the stress-donating layer before fusible layer melting, eliminating the need for post-stress modification steps. This preliminary configuration simplifies the overall process by removing complex post-processing operations while maintaining precise stress state 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 method allows for a thicker, crystal-defect-free semiconductor layer with increased integration density and versatility in stress state engineering, achieving higher material savings and integration density compared to previous methods.
Implementation Method 1
at least partial melting of the fusible layer, such that the stress-donating layer transfers, at least in part, by relaxation, the second stress state into the semiconductor layer
Implementation Method 2
the stress-donating layer transfers, at least in part, by relaxation, the second stress state into the semiconductor layer
Data Source
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AI summary
Title: Method for realizing a stress state in a semiconductor layer The invention relates to a method for realizing a uniaxial stress state (C3, C3') in a semiconductor layer (13), Said method comprising: - Providing a stack comprising a support (10), the semiconductor layer (13) and an intercalated fusible layer (11), - Forming a stress-donating layer (14) on the semiconductor layer (13), - Partially altering the stress-donating layer (14), modifying a first stress state (C1) of the layer (14) to obtain a second stress state (C2) in a single direction (y), - Melting the fusible layer (11f), so that the stress-donating layer (14) transfers by relaxation the second stress state (C2, C2') into the semiconductor layer (13).