Semiconductor Device Isolation Layers With Different Insulation Materials
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Solution Overview
Problem
In semiconductor device fabrication, forming device isolation layers in trenches with varying depths and aspect ratios leads to voids and variations in active region widths, particularly in peripheral circuit regions, affecting gap-filling characteristics and threshold voltage consistency.
Innovation Solution
Different trench formation processes and insulation materials are used for cell array and peripheral circuit regions, allowing for tailored trench depths and widths, and adjusting oxide and liner layer thicknesses to prevent voids and maintain uniform active region widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single insulation material is used to fill all trenches regardless of depth and aspect ratio, then the fabrication process is simple, but voids form in trenches with large aspect ratios
Solution Approach 1:
The patent applies local quality by using different insulation materials for different trench types. Specifically, a first insulation material is used for trenches in the cell array region, while a second insulation material is used for trenches in the peripheral circuit region. This allows each region to be optimized for its specific requirements, preventing void formation in high aspect ratio trenches while maintaining process efficiency.
2Reliability
If trenches in peripheral circuit region have varying depths and aspect ratios, then device isolation can be achieved, but voids form and active region widths vary
Solution Approach 1:
The patent implements local quality by differentiating the insulation material selection based on trench location and characteristics. Trenches in the peripheral circuit region with varying depths receive a second insulation material optimized for their specific geometry, while trenches in the cell array region receive a first insulation material. This localized approach ensures proper filling for each trench type, maintaining active region width uniformity.
Solution Approach 2:
The patent applies parameter changes by selecting insulation materials with different physical and chemical properties suited to different trench configurations. The first insulation material is optimized for cell array trenches, while the second insulation material is optimized for peripheral circuit trenches with varying aspect ratios. This parameter optimization prevents void formation and ensures consistent active region widths.
3Manufacturing precision
If different insulation materials are used for different regions, then void formation is prevented and active region widths are uniform, but the fabrication process becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing the substrate into distinct regions (cell array region and peripheral circuit region) and applying different insulation materials to each region. This segmentation allows for optimized filling in each region while maintaining a systematic and organized fabrication process, reducing the complexity that would arise from attempting to handle all trenches uniformly.
Data Source
AI summary
A semiconductor device comprising a trench device isolation layer and a method for fabricating the semiconductor device are disclosed. The method comprises forming a plurality of first trenches on a first region of a semiconductor substrate, filling the first trenches with a first insulation material to form first device isolation layers, forming a plurality of second trenches on a second region of the semiconductor substrate, and filling the second trenches with a second insulation material different from the first insulation material to form second device isolation layers, wherein the first trenches and the second trenches are formed using different respective processes.