Integrated Deep and Shallow Trench Fabrication With Low Cone Defects
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Solution Overview
Problem
The process for fabricating conductive deep trenches in semiconductor devices is complex and prone to defects, particularly cone defects that can obstruct inspection processes and impact yield.
Innovation Solution
An integrated sequence is introduced where a shallow trench is etched and filled before a deep trench is etched and filled, reducing cone defects and process complexity by integrating the deep trench formation process with the shallow trench formation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If deep trench and shallow trench are fabricated separately with different processes, then each trench can be optimized independently, but the overall process complexity increases and defect density increases
Solution Approach 1:
The patent combines the deep trench isolation process and shallow trench isolation process into a single integrated sequence. The shallow trench is etched and filled first, then the deep trench is etched and filled in the same process run, allowing both trenches to be fabricated simultaneously with coordinated etch and fill parameters, reducing overall process complexity while maintaining optimization for each trench type
Solution Approach 2:
The shallow trench is fabricated in advance before the deep trench in the integrated process sequence. By completing the shallow trench etch and fill operations first, the process establishes a foundation that prevents cone defect formation in subsequent deep trench fabrication, while maintaining independent optimization capabilities for each trench type
2Adaptability or versatility
If conventional separate processes are used for deep trench and shallow trench, then process flexibility is maintained, but cone defects increase and yield decreases
Solution Approach 1:
The integrated process merges deep trench and shallow trench fabrication into a single coordinated sequence, maintaining process flexibility through independent parameter control for each trench type while eliminating cone defects that reduce yield. The simultaneous etch and fill operations are optimized to prevent harmful interactions between the two trench structures
3Manufacturing precision
If multiple separate fabrication sequences are implemented, then each trench type can be independently optimized, but manufacturing time and process complexity increase
Solution Approach 1:
The patent merges multiple fabrication sequences into a single integrated process that fabricates both shallow and deep trenches in one run. The process maintains independent optimization for each trench type through separate etch and fill parameter control, while significantly improving manufacturing efficiency by eliminating the need for separate process runs and reducing overall fabrication time
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 1E~1F
AI summary
A method (200) for fabricating conductive deep trenches in conjunction with shallow trench isolations in a semiconductor device. The described method introduces an integrated sequence during which a shallow trench is etched (210) and filled (220) before a deep trench is etched (230) and filled (240). The described method advantageously reduces cone defects and process complexity associated with the formation of a conductive deep trench within a shallow trench isolation structure. Fabricated under the integrated sequence, the conductive deep trench may extend through a shallow trench dielectric layer and into the substrate, where the top surfaces of both the conductive deep trench and shallow trench dielectric layer are substantially cone free.