Silicon Super Junction Trenches with P-Type Liner Rapid Fill
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Solution Overview
Problem
Conventional technologies face challenges in scaling high aspect ratio features in semiconductor devices due to issues with maintaining straight sidewalls and filling recessed features without seams or voids, leading to performance limitations and structural flaws.
Innovation Solution
The approach involves forming a thin epitaxial P-type liner in trenches and filling them with a passive fill material, allowing for increased aspect ratios and manufacturing throughput without affecting device operation, even with voids or seams in the passive fill material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching and filling methods are used for high aspect ratio features, then device scaling is limited, but manufacturing throughput and efficiency are reduced
Solution Approach 1:
The patent applies preliminary action by forming an epitaxial liner layer in the trench before filling it with passive material. This pre-prepared liner structure enables subsequent rapid filling processes to proceed efficiently without compromising the final feature dimensions, thus resolving the contradiction between manufacturing precision and productivity
Solution Approach 2:
The filling process is segmented into two distinct stages: first forming the epitaxial liner layer, then rapidly filling the remaining trench space with passive material. This segmentation allows each stage to be optimized independently - the liner ensures precision while the rapid fill maximizes throughput
2Manufacturing precision
If longer etching times are used to maintain straight sidewalls, then feature quality improves, but manufacturing cycle time increases
Solution Approach 1:
The epitaxial liner is formed as a preliminary structure before the main filling operation. This pre-formed liner provides the template for straight sidewalls, eliminating the need for prolonged etching cycles to achieve the same quality, thus reducing manufacturing cycle time while maintaining feature quality
3Reliability
If complete trench filling without voids is required, then device reliability improves, but manufacturing complexity and time increase
Solution Approach 1:
The patent uses a disposable epitaxial liner layer that is subsequently filled with passive material. The liner serves its purpose during the filling process and is not required to be perfectly void-free in the final structure, allowing simpler and faster filling processes that maintain sufficient device reliability without excessive complexity
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 enables the creation of high-aspect ratio features with improved manufacturing efficiency and reduced device size, overcoming limitations in conventional technologies by defining pillar widths through the epitaxial liner and rapid backfilling with passive material.
Implementation Method 1
forming a thin epitaxial P-type liner in trenches
Implementation Method 2
filling them with a passive fill material
Data Source
AI summary
A super junction device with an increased manufacturing throughput may be formed by forming narrow trenches lined with a P-type liner and rapidly filled with a passive fill material. Instead of etching trenches with aspect ratio large enough to reliably fill with doped P-type material, the aspect ratio of the trench may be reduced to shrink the size of the device. This smaller trench may then be lined with a relatively thin (e.g., about 1 μm to about 2 μm) P-type liner instead of completely filling the trench with P-type material. Inside the P-type liner, the trench may then be filled with a passive fill material. Filling the trench with the passive fill material may be carried out in a matter of minutes at relatively high temperatures, thereby likely causing a void or seam to form within the passive fill material. However, because the passive fill material does not affect the operation of the device, this type of defect can exist in the device.