Semiconductor Rear-Side Insertion via Epitaxial Spanning
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Solution Overview
Problem
The existing methods for manufacturing semiconductor devices face challenges in simplifying the formation of patterned structures at the rear side of a semiconductor wafer, particularly due to limited thermal budget and material restrictions, which complicates the formation of dielectric and impurity zones.
Innovation Solution
A method involving the formation of cavities in a semiconductor layer, followed by epitaxial growth of a second semiconductor layer that spans these cavities, allowing for the creation of rear side insertion structures with phase change materials, recombination structures, or impurity zones, thereby simplifying the alignment and processing of rear side structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dielectric structures and impurity zones are formed on the rear side subsequent to front side processing, then the semiconductor device achieves functional requirements, but the process complexity increases due to strict thermal budget constraints and material restrictions
Solution Approach 1:
The patent applies preliminary action by forming the rear side insertion structures (cavities, masks, plugs) before completing the front side processing. This allows the rear side structures to be pre-positioned and protected during front side manufacturing, eliminating the need for subsequent rear side processing steps and reducing overall process complexity while maintaining device functionality
2Temperature
If the thermal budget for rear side processing is limited, then the front side processing requirements are met, but the material selection and process options for rear side formation are restricted
Solution Approach 1:
The patent performs rear side structure formation preliminarily when higher temperatures and broader material options are available during early processing stages. Cavities are etched, mask liners are deposited, and plugs are formed before front side processing constraints are imposed, thereby expanding material selection flexibility while meeting thermal budget requirements
Solution Approach 2:
The patent uses sacrificial mask liners and plugs that are temporarily deposited to define cavity regions, then removed to create openings for insertion structures. These disposable elements enable flexible material selection during formation without compromising the final device, as they are removed after serving their patterning function
3Reliability
If patterned structures are formed at the rear side after front side processing, then the device achieves required functionality, but the alignment precision and processing efficiency decrease
Solution Approach 1:
The patent forms rear side insertion structures preliminarily before front side processing completes, establishing precise patterns and alignments in advance. This eliminates subsequent alignment operations and reprocessing steps, thereby improving manufacturing efficiency while ensuring the required device functionality is achieved
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 the formation of semiconductor devices with improved reverse blocking capability and reduced material constraints, allowing for a wider range of materials and processes to be applied to the rear side, enhancing the manufacturing efficiency and device performance.
Implementation Method 1
A second semiconductor layer is grown by epitaxy on the process surface, wherein the second semiconductor layer spans the cavity
Data Source
AI summary
A semiconductor device includes a semiconductor body and a rear side insertion structure. The semiconductor body has a first surface at a front side and a second surface parallel to the first surface at a rear side, an active area and an edge termination area separating the active area from an outer surface of the semiconductor body. The outer surface connects the first and second surfaces, and element structures in the active area are predominantly formed closer to the first surface than to the second surface. The rear side insertion structure extends from the second surface into the semiconductor body in the edge termination area.