STI Support Plate Formation to Prevent Active Area Shifting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The formation of shallow trench isolation (STI) in advanced semiconductor devices leads to issues such as bending or shifting of active area islands, causing electrical shorts and alignment difficulties in photolithography, resulting in lower yield.
Innovation Solution
The formation of self-transformed support plates within shallow trenches using silicon dioxide, which are formed by transforming silicon support plates during the thermal oxidation process, providing mechanical support to hold semiconductor structures in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shallow trench isolation is formed in advanced semiconductor devices, then isolation between active areas is achieved, but active area islands bend or shift from their ideal positions
Solution Approach 1:
Silicon support plates are formed in the shallow trenches before the final isolation fill process. These support plates are created by patterning and etching silicon regions that will later transform into structural supports, preventing active area islands from bending or shifting during subsequent processing steps
Solution Approach 2:
The support plates undergo thermal oxidation transformation, changing from silicon to silicon dioxide. This parameter change in material composition and physical properties provides mechanical support to hold active area islands in their ideal positions while maintaining compatibility with the surrounding isolation structure
2Reliability
If shallow trench isolation is formed, then electrical isolation is achieved, but alignment of photolithography becomes difficult
Solution Approach 1:
The support plates are formed and transformed before the photolithography alignment steps. By establishing the mechanical support structure in advance, the active area islands maintain their ideal positions throughout subsequent alignment-critical processes, ensuring accurate photolithography patterning
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
The solution effectively prevents bending or shifting of active area islands, enhancing process window and yield by ensuring accurate alignment in subsequent photolithography steps.
Implementation Method 1
a thermal oxidation process is executed such that a silicon dioxide liner layer is formed along each of the shallow trenches and the silicon support plates are self-transformed to silicon dioxide support plates
Data Source
AI summary
The present invention provides a method for forming self-transformed support plates in shallow trench isolation for advanced semiconductor devices, in which after a photolithography process to define active areas on a silicon substrate, an additional photomask is implemented to add a support plate patterning layer in areas where silicon will be etched during a STI etching step to form STI trenches. Tiny silicon support plates inside the STI trenches are formed after the silicon etching. These silicon support plates may provide mechanical support to hold neighboring patterned strips where the active areas are defined or neighboring active areas islands, and preventing them from bending, deformed or shifting. An alignment of photomask pattern at following photolithography process is eased.